BRE Housing Guide

Building Research Establishment Report ctisfe 81 (A3) 1993

BRE housing design handbook Energy and internal layout%

EnerRy Effickncy Office

Building Research Establishment Report

BRE housing design handbook: energy and internal layout

Building Research Establishment Garston Watford WD2 7JR

- _-- Prices for all available B E publications can be obtained fiom: CRC Ltd 151 Rosebery Avenue London, EClR 4QX Telephone: 0171 505 6622 Facsimile: 0171 505 6606

BR 253 ISBN 1 86081 163 9

0 Crown copyright 1993 First published 1993 Reprinted 1994 Facsimile reproduction 1997

Applications to copy all are part of this publication should be made to: Construction Research Communications Ltd, PO Box 202, Watford, Herts, WD2 7QG

Contents

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

Chapter 7

Chapter 8

Introduction

Occupants’ requirements An overview Orientation and layout Internal environment

Page 1

7 9

10 13

Site layout, built form and microclimate 17 Principles and objectives 19 How climate varies 20 How to improve microclimate 26 Choosing the right building design and site layout 29

Orientation, sunlight and solar gain Overall guidelines Window design and orientation Room layout Conservatories Safeguarding existing buildings

Orientation and daylight General requirements Site layout for good daylighting Interior daylighting Protection of existing buildinw

Privacy and noise Introduction Describing noise External noise control Insulation against airborne noise Insulation against impact noise Upgrading existing dwellings

Security Introduction Houses Doors and windows Flats

Fire Introduction General Single-family dwelling houses only Flats: internal planning Maisonettes: internal planning Flats and maisonettes Flats and maisonettes: beyond the dwelling Construction: all dwellings

31 33 36 37 38 39

41 43 43 45 47

49 51 52 52 53 55 56

59 61 64 65 68

75 77 78 80 82 84 85 86 89

BRE housing design handbook ... 111 -.

Chapter 9

Chapter 10

Chapter 11

Chapter 12

Chapter 13

Chapter 14

Safety Introduction Doors Floors Windows Check-list on safety

91 93 95 96 98

101

Energy efficient design 105 Introduction 107 Factors affecting energy efficiency 108

112 Calculating energy requirements 110 Good practice in the design of new housing

Thermal insulation Introduction General guidelines The Building Regulations Roofs Wall insulation Doors and windows Floors

Space and water heating Principles of heating System choice Common heating systems Other heating systems Heating system design Hot water system design Controls Radiators Building Regulations

Internal environment Ventilation requirements Airtightness Ventilation requirements Trickle ventilators Passive stack ventilation Extractor fans and controls Mechanical ventilation systems and heat recovery Heat recovery extract fans Ventilation for tumble dryers Ventilation of roof spaces Ventilation under floors Radon

Services and drainage Introduction Basic principles Plumbing design Details

115 117 117 118 119 121 131 133

135 137 137 140 155 157 159 159 161 161

167 169 170 174 175 176 177 180 183 183 184 185 185

187 189 189 194 198

iv BRE housing design handbook

Materials for above-ground drainage Ducts Economies Drainage services Refuse disposal systems Water services Electrical services Gas supply

Chapter 15 Circulation living rooms and bedrooms Introduction Space for activities Mobility standards for ambulant disabled people Furniture and equipment sizes Circulation: eating and sitting areas Circulation: sitting areas Circulation: sitting and writing areas Circulation: living areas Circulation: bedrooms Check-list

Chapter 16 Kitchens Key issues Equipment: food storage Equipment: cleaning materials Equipment: sinks Equipment: dishwashers, cookers and hobs Activities spaces Check-list

Chapter 17 Utility areas Key issues Drying and ironing Check-list

Chapter 18 Bathrooms Introduction The bath The shower The washbasin The bidet The WC Relationship between spaces Layout Check-list

Acknowledgements

References

British Standards Institution publications

Index

200 202 203 204 206 206 207 21 1

213 215 215 222 225 228 229 230 231 232 233

237 239 244 246 247 249 250 261

263 265 268 270

27 1 273 274 275 275 276 276 277 279 281

285

285

288

290

BRE housing design handbook

BR 253

Chapter 1

Introduction

i

Introduction This book will be useful to designers of new and refurbished housing, irrespective of their experience. It will help clients, contractors, developers and all those involved in the process of house building, in both the private and public sectors, to appreciate the wide range of user requirements that must be addressed in the design of housing.

As a reference book it provides a means of checking that housing design criteria have been met adequately. It also suggests how to achieve customer satisfaction by meeting their most important needs.

BRE studies of quality in traditional considerable room for improvement in areas which are the responsibility of the designer; around 30% of all infringement of requirements observed in these studies were directly attributable to the designer. These findings are confirmed by the experience of the BRE Advisory Service.

show that there is

It can be argued that the designer should also help to reduce those faults which are considered to be the responsibility of site staff. Many of these faults relate to recently introduced energy conservation requirements - a topic which is likely to become increasingly important in view of public concern over ‘green issues’.

This book:

covers in depth many of the main criteria upon which design decisions depend, such as the space required to carry out the main activities in the dwelling;

summarises essential dimensional and performance information on dwelling design from official publications - most of which are now out of print - and places it in the context of more recent information and criteria from the energy programme, taking account of ‘green issues’;

gives the basis of choice, rather than ‘hard and fast’ rules, presenting a minimum of information where a wide choice of design criteria (such as room areas and shapes) is allowed;

presents criteria relevant both to new and to rehabilitated dwellings, although with the latter category there is a much reduced range of design options. Only the main criteria are given (sources of supplementary information are given in references).

Design skills Design is always a compromise. The skilled designer minimises conflicts and maximises the number of important items in the brief that can be fully satisfied. It should not be assumed that any one design can satisfy all the separate requirements in this book.

Planning requirements This book cannot deal adequately with all factors which relate to planning and siting of the dwelling and which influence occupier satisfaction, such as pleasant surroundings and easy access to services, particularly public transport. Nor can it deal in detail with some recent trends in the housing

BRE housing design handbook PREVIOUS PAGE IS BIANK~

I

Introduction

BREEAM seeks to: 0 Raise awareness of the important

role buildings play in global warming through the greenhouse effect, in the production of acid rain and in the depletion of the ozone layer

0 Reduce the long-term impact that buildings have on global and local environmental hazards

0 Improve the quality of the indoor environment of buildings

0 Set targets and standards, independently assessed, so that false claims of environmental friendliness can be avoided

0 Provide a means for builders to design, and home buyers to recognise, environmentally better buildings, and so stimulate the market for them

Issues to be considered in an environmental assessment The issues currently addressed by BREEAMiNew Homes are:

0 CO2 emissions resulting from

0 CFC (chlorofluorocarbon) and energy use in the home

HCFC (hydrochlorofluoroaubon) emissions

materials 0 Natural resources and recycled

0 Storage of recyclable materials 0 Water economy 0 The ecological value of the site 0 Ventilation 0 Volatile organic pollutants of

0 Wood preservatives 0 Man-made mineral fibres 0 Asbestos and lead

0 Smokealarms 0 Storage of hazardous substances

Criteria given in bold are summarised in this publication. For the remainder, see Reference 3.

indoor origin

0 Lighting

I

4

market: an increase in one- and two-person households, trading up and down the housing market (as family size and circumstances change), greater experimentation with house types, and greater demand for specialised housing for the elderly, young single people, ethnic minorities, disabled people and others.

User requirements There are rising expectations amongst all income groups for improvements in their accommodation standards. This in turn affects many requirements either directly, such as the standard of service from electrical or mechanical installations, or indirectly, such as the inherent risk of accident in the dwelling.

These changing user expectations are reflected in many ways: for example, through private sector publications or organisations such as the National House Building Council (NHBC) as well as through the policies of the Housing Corporation, Housing Associations and Local Authorities. Some basic requirements are included in national Building Regulations. It is unlikely that the scope of future European regulations will ever be widened to include all habitability and economic considerations, in addition to health, safety and resource conservation.

Green issues Although public awareness of the growing importance of environmental issues has increased, there is generally less awareness of the contribution that good housing design can make in reducing pollution and improving the environment.

This book summarises the main features of BREEAM, (the Building Research Establishment’s environmental assessment method) for the design of new homes3. BREEAIWNew Homes represents the current BRE targets for good practice. Its criteria are valid even though a designer may prefer to carry out a critical analysis of the design personally rather than seeking an independent assessment.

BREEAh4bJew Homes seeks to minimise the adverse effects of new homes on the global and local environment while promoting a healthy indoor environment. In the assessment method, credit is given for housing designs judged to follow improved environmental practice.

Performance and prescriptive requirements Requirements can be expressed in two ways, either by stating the solution (prescriptive) or what is to be achieved (performance). This book contains requirements expressed in both ways. Although requirements should ideally be put to the designer in performance terms, so that solutions are thereby not unnecessarily prejudiced, it is not yet possible to deal with all requirements in this way.

For performance requirements, only the primary ones, which stem more or less directly from human or equipment needs in the finished dwelling, have been given.

Secondary performance requirements have not been included since they are difficult to foresee. Secondary performance requirements result from


design consequences (such as a particular choice of layout of accommodation or use of particular materials) or relate to requirements likely to arise during construction, or a combination of these factors.

See Reference 4 for a full discussion of the use of performance specifications for dwellings.

Conflicts between requirements Some requirements can conflict with each other. For example: there is a direct conflict between a requirement for privacy in the immediate surrounds of the house, and a requirement not to provide cover for a housebreaker; and a conflict exists between the need for a view out of a bedroom window for someone who is ill, and the need in normal circumstances for a higher sill to allow a degree of privacy where the room is overlooked by other buildings.

Some aspects are easier to quantify than others; and there is a danger when trying to define user requirements and preparing briefs for design that the more difficult items suffer in comparison to the easier, even though they may be more important.

In the case of an external door, for instance, there may be two requirements to consider: the door must be weathertight and it must be safe and convenient for the user. To achieve a reasonable degree of weathertightness with current designs of doorset (if there is no porch) a sill or weather-bar must be used. This may solve the weathertightness requirement, but it makes access difficult for pushchairs and wheelchairs. By giving priority at the brief-preparation stage to achieving weathertightness (which is relatively easy to quantify), safety and convenience (which is not so easy to quantify) could suffer.

Specifiers and designers need to show a considerable degree of ability and skill to resolve this sort of conflict of requirements. (See Reference 5 for a full list of user requirements for briefing.)

Trade-offs in design The problems for the specifier and the designer remain. How can those who draw up the brief avoid being unnecessarily prescriptive, and how can the designer be given the widest latitude in seeking trade-offs in design?

Conflicting design aims have been resolved in past practice by cutting quality levels. Many building components now have lives significantly shorter than that expected of the main fabric; if they can be replaced with minimum effort, the quality of the dwelling can be more easily enhanced. An alternative that is more in spirit with the performance approach might be to maximise the initial provision of space to allow a modicum of change of use at an acceptable overall cost. Occupiers’ needs are bound to change more than once within the lifetime of the fabric; the greater the space, the easier it will be to accommodate change.

Performance values should be given as ranges so that the respective merits of some attributes can be traded off against others where compromise is needed. It is useful, therefore, to think of perforniance of which the various levels have differing degrees of acceptability (eg minimum, acceptable, desirable, essential) in various circumstances.


_. -- - - -

Introduction

Evaluation of designs Most requirements in this book relate to the completed dwelling in use rather than to construction techniques or precautionary measures. The evaluation of any proposed building design -whether for energy efficiency, green issues or simply the layout and provision of space - must consider the practicality of construction and the consequences of any likely discrepancies from the design.

Sometimes only a rough prediction can be made of how conditions like air infiltration or cold bridges might affect the behaviour of a dwelling after construction. For this reason, dwellings will need reassessing and monitoring during construction, possibly necessitating design modifications in later versions.

Well designed (not ad-hoc) remedial measures are needed when adopting in-situ testing of completed construction as the primary evaluation method (as some countries have done) and applying it on a large scale. It would seem more efficient to try to develop better predictive methods and controls, wherever possible, but it should also be borne in mind that assessments themselves are subject to variability. This is compounded with the variability of products and site workmanship, and experience shows that this is a strong influence on the assessment of performance in use.

A fundamental dilemma in the design of housing is that any particular design will rarely be ideally suited to the needs of its occupants during its lifetime. On the other hand, the design may prove satisfactory under conditions more demanding than those provided for in the design, simply because the occupants may decide to tolerate some mismatch between the performance of their dwelling and their expectations. The best solution may be for the occupants to move houses as their requirements change, given the availability of a wide range of house designs, but this does point to the undesirability of too much repetition of standard designs.

A draft of this book was circulated to about twenty leading organisations and individuals within the industry and, wherever possible, the text reflects a consensus of the views submitted.

This book does not contain mandatory Government requirements for housing, despite the fact that BRE is a Government Agency. The contents are essentially recommendations of good practice. The best starting point for designers is still mostly found in the publications cited in the Reference section at the end of the book.

6 BRE housing design handbook

_ -

Chapter 2

Occupants’ requirements

Occupants' requirements

An overview Optimal housing design This chapter lists recommendations based on the findings of actual surveys. Some recommendations may appear obvious, but they are included for completeness, and some readers may disagree with views expressed by respondents to surveys, but this illustrates the difficulty of providing single solutions to satisfy everyone.

Figure 1 only shows the links between the items that have the most direct effect on the requirements, but to some extent all the requirements are affected by all the components. Unfortunately this high degree of interaction means that conflict can occur between requirements and the properties of a particular component. For example, although a large window may increase the amount of light entering the home it may also reduce privacy and cause more heat loss. Although perfection may never be reached, the optimum design may be achieved by making compromises. When designing the home, the effect that properties of a specific component have on all occupant requirements should therefore be taken into account.

Insulation I system


figure 1 Relationships between people, requirements and components

I PREVIOUS PAGE IS BLANK I


Orientation and layout Noise control Surveys have shown that most people prefer a new home to have good sound insulation6. Occupants seem particularly concerned about noise caused by neighbours: specifically their children, vehicles and find that their perception of what causes a noise can be more disturbing than its level, especially if it represents an activity which is deemed unnecessaryg. Voices may therefore prove to be more distracting and disturbing than less identifiable sounds. Problems can be mitigated in the following ways:

They

Provide good sound insulation materials in walls and floors. The structure of a building will also determine how it transmits sounds. For example, unsealed pores and ties in cavity walls increase sound transmission and non-rigid layers may vibrate, thus reducing sound insulation.

Place the children’s bedrooms away from the toilet and bathroom. This will prevent the children being awakened by adults preparing for bed later in the night.

Use planted earth mounds to screen-out noise sources, eg traffic noise.

Place footpaths away from windows to reduce the noise from passers-by.

Use good layout to reduce noise on the estate coming from children. For example, incorporate a park into the estate or keep family homes away from those associated with single people or young couples, such as flats and bedsits.

Arrange the layout of dwellings so that old people, while still fully integrated, are protected from the noise generated by the younger households.

Privacy Acoustic and visual privacy If occupants can hear their neighbours, the neighbours can hear them9. Being overlooked by passers-by can infringe privacy. Open planning gives a better sense of space for larger households but reduces visual and acoustic privacy. It may also increase energy consumption.

Adopt the screening methods used for reducing noise for improving privacy. For example, site paths away from windows.

Maintain a careful balance in the levels of screening. Some occupants, particularly the elderly, like views of activity as well as greenery, and parents like to be able to watch over their children.

Provide where possible an enclosed garden in which children can play safely and which occupants can use in private.

Position windows where they are unlikely to interfere with privacy. If possible, avoid positioning large (patio) windows where they can be overlooked from public areas.


~-

Orientation and layout

Domestic privacy Privacy from another occupant or other occupants will often be necessary. Most studies have found that privacy in the home is directly related to the number of people resident.

0 Increase the number of rooms by adding more divisions in the house plan to improve privacy. This also increases circulation space but reduces the size of the rooms and the space available for activities.

This can be expensive but it is one of the key lessons of UK family housing experience in relation to large families and is worth paying for. A n alternative is to include a kitcheddining room.

family homes. Families prefer this because it permits a more flexible arrangement.

This has considerable advantages in family households where a number of activities are taking place at the same time.

0 Provide two living-rooms rather than one.

0 Provide extra smaller rooms rather than fewer larger rooms in

0 Physically separate the dining area from the living space.

Circulation The bedroom is obviously considered one of the most personal areas in a family home. It is also seen as an area where a member of the family can retreat for peace and quiet. The bathroom may be the most private area but, unlike the bedrooms, it tends to be used by the whole household.

0 Provide one bedroom for each child in the household if possible. As the family grows the only practical solution may be to provide extendable dwellings.

rather than through another person’s bedroom. Additional ensuite bathrooms are also popular.

from inside. Access should preferably not be through the living-room, especially in family homes.

0 Provide an area for receiving guests before they enter the more private areas of the home. People like a buffer such as an entrance hallway and possibly the kitchen between private and public areas. Halls and draught lobbies also reduce draughts and heat losses.

0 Provide access to bedrooms and bathroom from the hallway or landing

0 The kitchen should be accessible directly from outside as well as



Living areas BRE studies found that dislikes in a range of new homes mainly related to size - particularly the size of the kitchen and the bedroom and the lack of storage space7J0. As discussed earlier, space and privacy are interrelated and designs which are good for privacy may not be so good for space. The living-room is thought of as a social area where the family can meet; it

also probably the most multi-purpose room.

The living-room needs to be large enough for the family and guests to meet and to hold the equipment and furniture needed for various domestic activities. It may be difficult if not impossible to provide for this in practice, especially where cost is a prime consideration. Extendable dwellings may provide some solution.

Ensure that each member of the household has his or her own bedroom. For large families the bedroom can be used as an alternative to the living area when there is a potential clash of activities.

Use large windows to achieve a better sense of space. This is particularly effective if i f they overlook green areas, although they tend to lose more heat even if double glazed.

Kitchens Several recent surveys have shown that occupants find their kitchens too smal17J0. Kitchens, like living-rooms, tend to be multi-purpose areas which are used for socialising and eating as well as for food preparation and domestic duties. In 1961, the Parker Morris Report recommended that kitchens should be built large enough to take meals in, even if this reduced the living-room areall. However, in many recently built houses space has generally been reduced first in the kitchens.

0 Provide a dining recess in the kitchen in preference to an open plan

0 Provide space for a large table in the kitchen, if possible.

0 Provide enough space in the kitchen for casual meals at least and other

diningfliving-room.

social activities if possible.

Bedrooms Bedrooms are not just used for sleeping in; they may also be used for recreation, study or entertaining guests.

0 Make bedrooms (especially children’s bedrooms) large enough to

0 Provide built-in wardrobes if possible.

accommodate a desk.

Bathrooms 0 Remember that the bathroom needs to be large enough for occupants

0 Provide enough space to wash a bsby safely and in comfort.

to dry themselves in.


’- ~~ -

Internal environment

Storage Occupants feel that new homes lack sufficient storage areas7.10, despite the fact that storage areas do not necessarily take up more living space.

0 Attic space can provide extra storage space.

This is particularly so if the attic has been floorboarded, although this is not practical with current designs of trussed rafter roofs. Such attic spaces, when used for storage, should preferably be included within the heated envelope of the dwelling. Current Building Regulations call for 150 mm thickness of thermal insulation, which is likely to exceed the usual ceiling joist depth. This makes it impossible to board such spaces after completion of the dwelling, unless they are built up. It is also desirable that appropriate floor loadings are taken into account in sizing the ceiling joists.

0 Storage can be in circulation spaces or above work surfaces, especially in bedrooms and kitchens. It must be remembered that these spaces can be dificult for elderly and disabled people to reach.

0 Cupboards can also be built into furniture, such as drawers under beds. If built-in cupboards are notprovided, the occupant makes the choice when buying furniture.

0 Garages, garden stores or outhouses can also be used for storage by occupants.

Note: Care should be taken about building-in cupboards on external walls where there may be a risk of condensation and consequent mould problems.

Internal environment Heating Heating has always been considered a basic requirement in living-roomsI* and bedrooms (especially children's bedrooms). An effective and economic heating system is therefore required. Heating systems with multiple components such as a timer, thermostat and immersion heater switch must be easy to operate and clear, easily understood operating instructions should be supplied.

0 When in use the living-room temperature should not, even by accident, fall below 16"C, particularly in homes for the elderly. The normal requirement is for a minimum of 21 "C. The heat source required by NHBC, for example, should be capable of maintaining this temperature.

0 Heat from the ground floor living areas can be used to advantage. This heat penetrates the upper floor spaces, thereby reducing the amount of direct heat needed in the bedrooms.

from the main living area. Unheated halls can be a source of cold draughts reaching the living areas, however.

0 Lobbied entrance hallways and porches may help to reduce heat loss

0 Stairs which open off living areas may waste heat.

0 Allow easy access to meters so that both the official meter reader and the occupant can easily read them.

13 __ - - BRE housing design handbcok

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Occupants ’ requirements

0 Select meters that can be read and interpreted easily.

0 Keep the controls for central heating systems simple for ease of operation. Tappets are particularly difficult to use if the operator is arthritic or short sighted. Electronic controls are now recommended, but they may need more explanations.

0 Select heating devices with instructions for use printed on them so that they do not get lost.

Refer to Chapter 12 for a fuller treatment of these topics.

Air quality Poor ventilation combined with inadequate heating and insulation may produce condensation problems. This could cause a build up of mould and fungi13. The ventilation requirements for homes are covered in the current Building Regulations and the various means of providing adequate ventilation are described in Approved Document F.

0 It is important that heating, ventilation and insulation are considered as a single design package. This will help to overcome problems of condensation and mould growth that might otherwise occur later.

0 Use ventilators to provide a desirable additional means of ventilation. Opening windows for ventilation may create both a security and a safety risk, and let in noise or pollution from outside. Ventilators are currently required in kitchens and bathrooms under the Building Regulations if there is no other means of ventilation.

Refer to Chapter 13 for a fuller treatment of these topics.

Lighting A survey carried out in 1983 found that two-thirds of the homes visited were inadequately lit14. Poor lighting in particular could be linked to accident@. The public needs better information on lighting matters and designers should be able to do more to assist.

0 Ensure that new homes receive adequate natural lighting, particularly

0 Ensure the windows are well placed and unobstructed by overshadowing.

0 Provide plenty of conveniently placed electrical sockets for lamps.

0 Consider the provision of adequate lighting points but ensure that they

0 Avoid too much screening for privacy as this may affect the amount of

0 Housing layout and orientation will also effect the natural light reaching

around the stairs and in the kitchen as a first priority.

allow for low-energy lighting, fluorescent tubes and bulbs.

daylight penetration.

the home. See Chapter 5.

given to the use of low-emissivity glass. Such windows always give some passive solar heating; it is largely a matter of optimisation. It should be remembered that large windows also increase heat loss.

0 Large south-facing windows should be double glazed, and consideration



Health and safety Occupants preferred7*l0 their homes to be in an area free from heavy traffic, because it is less noisy and also safer for children.

Kitchens are the area in the home most prone to accidents12. Various Department of Trade and Industry home accidents surveillance system reports also indicate kitchens and staircases to be areas most prone to accidents.

Poor lighting may also contribute to risk of accidentsI4.

The safest kitchen layout is a work surface/cooker/work surface/sink/work surface layout uninterrupted by doors or other obstructions.

0 Surfaces should all be the same convenient height and shelves should be well placed (eg not over the cooker) and reachable.

0 Wall-mounted cupboards should not be positioned over cookers. This reduces the risk of objects falling onto hot pans.

0 Ensure that the kitchen is well lit and provide adequate light switches around stairways.

0 Avoid single steps in unexpected places wherever possible.

0 If winding stairs are unavoidable, it is safer to provide them at the bottom of the stairs rather than at the top.

Basic amenities When occupants were asked what they considered to be the basic requirements of a home they listed: electric light, hot water supply, bathroom, refuse disposal, internal WC, living-room heating, ample power points, freedom from damp, good ventilation and daylightg. They also wanted street lighting, an airing cupboard, a ventilated food cupboard, general storage convenient for shops, a back garden, good thermal and sound insulation, bedroom heating, quiet surroundings, greenery, a well maintained property. Also of significance, but outside the control of the designer, were good neighbours and freedom from heavy traffic12. Occupants also preferred the WC separate from the bathroom, and in homes for larger families an extra WC on the ground floor was also required.

Refuse disposal was high on the list of priorities, although it was given scant attention by most designers. It is not covered in this publication.

Shelter, good structure and attractive environment Occupants require much more than a basic shelter and a sound structure from their home. They also need an attractive environment and prefer homes built from materials which complement the surroundings. Owners specified an attractive environment in ‘nice’ easily maintained material^^,'^.

Access and convenience 0 The ideal home has front and rear entrances with easy access to

0 Homes should have ample parking, particularly off-road or garages.

the garden.

BRE housing design handbook 15


0 A home for the elderly should be in a location convenient for shops and

0 All homes should be built with wider doorways without thresholds but

a post office.

with ramped or level entrances. This is more convenient for disabled people and the elderly and requires little modification to standard dwellings. Many family homes end up being occupied by the elderly.

Se curit y Security may imply a safe home but security measures may also conflict with safety requirements. Whereas security is mainly concerned with keeping people out, ease of escape is a ‘safety’ matter. Although fitting locks on doors and windows is a good security measure it may also hinder escape in the case of fire. Similarly, the need for privacy may create too much isolation. This can also be a risk, particularly for the elderly. NHBC have recently altered their preference from a key-operated lock to a snib- operated lock, for this reason.

0 When building a house, security must be balanced against other factors

0 Entryphone systems, and the use of concierges in communal entrances,

such as safety.

are useful security measures.

Security aspects are dealt with in Chapter 7.


-

Chapter 3

Site and

layout, built form microclimate

Site layout, built form and microclimate

Principles and objectives Site layout for climate control Designing site layout, which is one of the first decisions made when planning a housing development, can have important effects on both amenity and energy efficiency. Wind exposure is high in many parts of Britain: on exposed sites wind shelter can improve the comfort and usefulness of external spaces. around buildings and reduce the cost of space heating. Climatically sensitive design of site layout and built form is also likely to add to the attractiveness and marketability of housing. Further information is given in BRE Digest 35016.

Benefits of wind shelter Wind shelter can be provided by designing, siting and orientating housing for mutual protection and by using landscape elements, particularly earth mounds and shelter belts. Walls, fences and smaller scale vegetation between and around buildings are also useful in reducing windiness. Design for wind shelter needs to match the character of the site, in terms of regional climate and microclimate.

Well designed wind shelter can:

0 reduce space-heating energy demand,

0 reduce exposure to driving rain, and thus the risk of water penetration and associated deterioration of exposed walls,

0 reduce wind damage such as tile stripping which is common on exposed sites, and

0 make external spaces warmer by reducing wind-chill and by allowing solar heat to build up in walls, pavings and external spaces generally; such conditions appeal especially to the young, the elderly, and to gardeners.

Development Control context To maximise these benefits, wind control needs to be considered in conjunction with site layout for sunlight, daylight and solar gain (see Chapters 4 and 5) . The balance between these will vary with regional and local climate and especially with topographic setting: for example, different strategies will be appropriate for rural and built-up areas and for sites in valleys, on hills or on the coast.

Opportunities for climate control will be lost or compromised unless they are given priority when road layout is being decided. In this and other respects, interaction with the Development Control system is important. Various Local Authorities wish to encourage climatically sensitive site layout in the interests of energy efficiency and reduced environmental impact.

BRE housing design handbook IPREVIOUS PAGE IS BMNK


How climate varies Regional climates The UK climate has significant variations that affect decisions about site layout and house design. The main influences are:

0 Air temperature This affects the severity and duration of the heating season, and is often expressed in terms of accumulated temperature difference, or ‘degree- days’ (Figure 2).

20

Figure 2 Accumulated temperature difference (degree-day) totals for base temperature of 15.5’C. September to May (average, 1957-76 data reduced to sea level)


--

How climate varies

0 Wind This increases space-heating demand through infiltration and other mechanisms, and reduces external comfort through wind-chill (Figure 3).

I Abbut 6 - 5

9-

0 4

c 7-

Qo

U n Q,"At 10 out 6-5 10

Figure 3 Isopleths of hourly mean wind speeds ( d s ) exceeded for 50% of the time at a height of 10 m above open, level terrain (average, 1965-73; data reduced to sea level)

BRE housing design handbook 21 .

/-


22

0 Solar radiation This offsets heating demand through solar gains, and improves external comfort (Figure 4).

li

11

Figure 4 Annual mean daily irradiation on a horizontal surface (MJ/m*) (average, 1951-70; data not reduced to sea level)


How climate varies

0 Drivingrain This affects the design of the external walls and other weatherproof elements (Figure 5).

0 below 400

0 400-800 ii:-n 10 I a

L/m2 0 800-1600 . . /

I Q P I P

above 1600 I

'he direction of he maximumis rom21O0 230" Ixcept where ndicated:

12 Q 5 6

11

10

9

0

Figure 5 Zones of exposure based on average annual directional driving rain index (rn*/s) for the worst direction in each location (average, 1959-73); data reduced to sea level)


J


/ / I \

I--------( / 0 5%

Figure 6 Wind rose Mean wind speed: percentage of all directions, October-April

Figure 7 Wind-chill rose Wind-chill index >900 W/mzN: percentage of all directions, October-April (Siple-Passe1 formula)

Wind and wind-chill Design for wind shelter requires information on the directional characteristics of the wind. It is often convenient to use a wind rose, which can be related visually to wind-sensitive and wind-protective features on site plans. Alternatively, accumulated totals of wind-chill can be plotted directly on a rose, emphasising the directions of the colder winds that are likely to have a greater impact on energy consumption and external comfort. The roses shown are expressed in terms of percentage of time, so that the totals for different arms of the rose can easily be added or compared.

Site climate General climate data give a broad picture of climatic severity and design needs: this is modified by the location and setting of the site. The severity of site climate is influenced by:

Altitude Generally colder, windier, and cloudier as altitude increases

. _,- @// -..- Figure 8

Coasts and other water bodies Less extreme temperatures, but windier

24

Figure 9


How climate varies

Aspect Solar access better and ground temperatures higher on south-facing slopes; converse on north-facing slopes

Built-up areas Warmer in winter and summer

/Annual accumuhted temperature difference below 15OC (degree days) 1951 -1 960 (from the Climate of London, 1965)

High buildings Surrounding areas experience higher wind speeds and some overshadowing

Figure 10

Figure 11

Figure 12



Trees and vegetation Can improve wind shelter and reduce summer temperatures; may cause overshadowing

Figure 13

How to improve microclimate Shading for solar control

Wind control - buildings 0 Limit extensive shading by trees and mutual shading by buildings,

consistent with the need for wind protection (eg avoid north-facing courtyards), to allow maximum daylight and solar radiation into spaces (winter: low angle sun).

0 Use shade from deciduous trees to protect spaces (and windows) from glare and overheating under strong solar radiation (summer: high angle sun).

Avoid large flank walls fa Wind sensitivity - single buildings dominant wind

0 Avoid large (especially high) walls at right angles to a dominant or

0 Use hipped roofs in preference to gable-ended roofs.

0 Step back facades of higher buildings.

0 Avoid flat and low pitched (up to 10") roofs, especially in low-rise

0 Provide planting or windbreaks to reduce high wind speeds at the

critical wind direction.

construction; use medium-pitched roofs (22' to 45").

corners of buildings. Avoid flat-roofed buildings and large cubical forms

Orientate long axis parallel to dominant wind

Figure 14


How to improve microclimate

Wind sensitivity - groups of buildings 0 Keep building layout irregular, rather than in regular lines or grids.

Avoid long, uninterrupted passages between buildings, which channel the wind.'

changes of height, which can induce down-draughts.

1.5 to 2.5 times their overall height, but avoid small gaps (eg up to 3 m) which can act as wind funnels.

0 Keep the heights of buildings as uniform as possible; avoid abrupt

0 Keep the distance between buildings fairly small, ideally in the range

0 Overlap buildings which meet at an angle, to limit wind funnelling.

0 Create courtyards where maximum shelter is required; orientate open-sided courtyards for shelter from dominant or critical wind direction (but also consider solar access).

0 Avoid tunnels through buildings; if essential, orientate for minimum wind sensitivity, andor couple with wind-breaks.

0 Where straight streets are unavoidable, limit length of flat facades to about 25 m, or introduce steps and staggers.

0 Use landscape techniques to maintain ground roughness in open parts of the site, and to provide local wind shelter for buildings and open spaces; earth mounding, trees, bushes, fences and open or porous walls can all contribute. Mature trees with open space around their trunks may need extra, low-level planting to avoid channelling the wind at ground level.

Wind control - site

Avoid long parallel rows of smooth-faced buildings

X Avoid funnel-like gaps between buildings

X at ground level

BRE housing design handbook 27 7 .- -


28

Value of landscaping Trees, bushes, walls, fences and ground profiling (eg mounds and banks) can all contribute to wind shelter, in addition to providing summer shade and a green environment generally (now a high priority for building users). Landscape design needs to complement the arrangement of buildings, following many of the same principles, eg avoiding funnelling of ground level winds. Fully-grown trees can offer substantial wind protection: being permeable to the wind, they are less inclined than buildings to generate down-draughts.

Major shelter belts may be feasible around or within large developments. More generally, smaller-scale planting can give local protection to buildings and open spaces, block channels for the wind and enhance ground roughness. Free-standing walls and fences also contribute to shelter, and may be designed specifically as semi-porous, artificial windbreaks, giving protection similar to vegetation. Obstruction of south- facing windows, and creation of heavily shadowed external spaces should be avoided, and the influence of vegetation on foundations must be considered.

Figure 16 Spinney Gardens housing; view looking NW. Courtesy of PCKO Partnership and ETSU.


Choosing the right building design and site layout

Choosing the right building design and site layout Strategies for highly exposed sites The benefits of solar gains (especially passive solar designs) may be difficult to realise in some settings. Topography and wind exposure may dictate that high insulation (HI) and wind shelter (causing overshadowing) are more important than larger windows and the resulting solar gains (SG). This needs to be considered for:

0 Sites with edge shelter or mature trees near houses: SG where windows receive more than 67% of potential solar radiation; HI elsewhere

0 Level sites with all-round wind exposure: shelterbelts on all or most edges, plus internal shelterbelts and other tree planting: the likelihood of substantial overshadowing suggests that the majority of dwellings should be highly insulated (eg 25% SG, 25% HI)

directions, and shadows from both buildings and trees are shorter; this suggests worthwhile benefits from solar gains (eg 75% SG, 25% HI)

0 North-facing slopes: topography exposes site to colder wind directions, and shadows are longer; this suggests little benefit from solar gains (eg

0 Cases where edge shelter is difficult to realise (eg hill crests and ridges, exposed sites near coasts): internal planting plus self-sheltering built forms such as enclosed courtyards suggest that most houses should be highly insulated (eg 33% SG, 67% HI)

0 South-facing slopes: topography gives shelter from colder wind

100% HI)


--

Chapter

Orientation, sunlight and solar gain

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Overall guidelines Sunlight in and around buildings is valued because it gives occupants a feeling of warmth and well-being. But the sun is also a valuable source of free energy. By following simple design guidelines, houses can be constructed to make the most of solar gain without costing significantly more to build than houses where the design does not take solar gain into account.

0 Lay out the site to provide as much access to sunshine as possible.

0 Space houses to reduce overshadowing.

0 Avoid overshadowing by nearby existing buildings.

0 Ensure enough sunlight reaches gardens and play areas.

0 Place main living rooms on south facades with ancillary spaces to the

0 Have main glazing areas on south facades; reduce north-facing glazing.

north.

Site layout for good sunlighting Designing for solar availability is much simpler if the site slopes down to the south so that buildings to the south block much less sunlight. On a north-facing slope it may be very difficult to achieve significant solar gains in winter. In these circumstances, the aim should'be at least to obtain sufficient sunlight for amenity purposes (see below)16.

Space out buildings to achieve solar gain in winter All houses benefit from solar heating during the winter months. Those that incorporate passive solar principles especially need solar gain throughout these months to function effectively as low-energy designs.

\. Obstructions in this area should be less than limiting height

Take section about this line

v South

Figure 17a Section F'igurel7b Plan

BRE housing design handbook 33 . - I PREVIOUS PAGE IS BLANK I

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To check whether this can be achieved, draw a section about an axis due south of the main glazed face of the building (Figure 17). Obstructions which lie on plan within 30" of due south of any part of the glazed facade, should subtend an altitude angle of less than 65" minus L when plotted onto the section. Here L is the latitude in degrees of the site. For middle latitudes, this should ensure three hours of possible sunlight throughout the year, and allow winter solar gain around midday when the sun is at its highest.

Narrow obstructions which are taller than this may be satisfactory, provided enough winter sunlight can penetrate around the side of them. This may be checked using the solar gain indicator in the BRE Report Site layout planning for daylight and sunlight'7.

Achieve suficient spacing for rooms for amenity purposes Sufficient spacing should ensure enough sunlight all year round, but where passive solar design is not appropriate (for example on a north-facing slope) sunlight will still be desired for amenity purposes.

British Standard BS 8206:Part 2 recommends that rooms should receive at least one-quarter of annual probable sunlight hours, including at least 5% of these between 21 September and 21 March. This can be checked using the BRE Sunlight Availability Protractor18, or the sunlight availability indicator in Site layout planning for daylight and sunlight. Alternatively, if no obstruction in the 30" arc either side of south (Figure 17) is higher than a line drawn in section at 80 minus L to the horizontal, then the criterion is satisfied. Here L is the latitude in degrees.

Hints on site layout Most roads should run east-west, with north-south link roads. This will allow most houses to have southerly orientations. Terraces in particular should be placed on east-west roads.

Bungalows and low-density housing should be placed at the south of the site to reduce overshading, with terraces and taller buildings to the north (although care should be taken not to obstruct existing buildings on sites to the north). Tall buildings can also be sited to the immediate south of road junctions.

The requirements for orientation should be balanced with other layout requirements; for example, privacy (see Chapter 6) which usually dictates back-to-back gardens. Layouts which slavishly follow one design criterion at the expense of others usually suffer from problems due to an imbalance of design requirements.

Trees and shading

0 Avoid siting trees close to south-facing windows. If trees have to be sited near buildings, choose a deciduous variety, t o allow sun penetration during winter.

Where possible, courtyards should be open to the south to avoid casting shadows over patios and outdoor sitting areas.

and other open space.

0 Limit self shading caused by protruding extensions o r courtyards.

0 Ensure enough sunlight is available in gardens, children's play areas

34 . .

. .


Overall guidelines

Sunlight is especially valued in play areas and gardens. It makes open spaces more pleasant and aids plant growth. As a minimum standard, at least three-quarters of the ground area in a garden or play area should receive some sunlight on 21 March. Sunlight at an altitude of 10" or less does not count in this calculation.

The sun-on-ground indicator described in Site layout planning for daylight and sunlight17 can be used to check whether this standard is met. It should be easily achieved in most open spaces, but areas to the north of east-west terraces, and courtyards, can be problem areas.

This standard is a minimum requirement. For key locations such as patios and sitting-out areas additional checks may be needed to ensure that they get enough sunlight throughout the year.

Figure 18 Passive solar housing at Gifford Park, Milton Keynes, showing the optimum spacing of terraces. The space heating requirements were less than 40% of standard UK dwellings. Much of this saving was due to the layout.

Figure 19 In the NBA TectonicslETSU site layout study, a conventional layout of houses was predicted to have an average heating demand of 8900 kWhlyear. Rearranging the site (plan b) to reduce overshadowing and improve orientation of most dwellings would save an extra 100 kWhlyear. Changing to passive solar design would save an extra 800kWhlyear per house; an overall reduction of 10% in heating demand. Note that there could well be increased road costs to take into account.

BRE housing design handbook 35 c -~ ~ -. I


Window design and orientation Have main glazing areas on south facades South-facing windows provide the greatest solar gain. Over the heating season, south-facing windows which are double glazed or better can have a positive energy balance so it is better if the larger windows are concentrated on this face. Although double glazing will reduce solar gain, the net heat loss over the heating season is likely to be less than with single glazing.

Figure 20 Each house has a large south-facing window

0 Glazing should face near due south Face the main area of glazing within 20-30" of due south to make the most of solar gains. South-west and south-east-facing double glazed windows also save energy but not as significantly.

0 Reduce north-facing glazing North-facing windows have a negative energy balance. Over the heating season they allow more heat to escape from inside the house than they admit from diffuse solar radiation. Windows on the north side of a house should be kept to a minimum although the need for daylight and view out should be borne in mind (see Chapter 5) . Glazed panels within 800 mm of ground level should be of safety glazing.

Closing curtains at night is also a very economical procedure which should be recommended to occupants.

0 Provide adjustable shading Overheating can be a problem in summer with large south-facing windows, though complaints are comparatively rare in housing. Adjustable shading for windows in summer and good natural ventilation can help. Windows should be openable and should be fitted with blinds or curtains to reduce solar heat gain. Shutters are best for keeping out unwanted heat gain in summer. Awnings and overhangs can provide shade from summer sun while admitting low-angle winter sun.


Room layout

Room layout Site main living rooms on south-facing side of house People like sunlight in their living rooms, and are likely to regard a living room which faces more than 90" from due south as insufficiently sunlit.

In flats and maisonettes, ensure every flat has at least one main living room with a window facing within 90" of due south to avoid appearing cold and unappealing. For passive solar heating sunshine should be received directly into living rooms. In this case the main glazing area of principal living rooms should face within 2Ck30" of due south.

Figure 21 On the Parklands Estate, Bournville, garages and car ports are placed on the north side of terraces

Place ancillary and circulation spaces on north-facing elevation Areas which do not require sunlight should be placed on the north side of the house. These could include hallways, bathrooms and storage areas. External accommodation such as garages can be used as buffer zones on northerly facades.

Locate kitchen away from main solar gains Kitchens should be on the north side to minimise overheating in summer.



Conservatories Often a valued addition to a home, a conservatory can save energy by acting as a buffer zone between the cold outside and the warmth inside. To maximise any energy savings:

Do not heat the conservatory since it is extensively glazed and so will act as a weak thermal link. This means that the conservatory may not be habitable for much of the winter.

Face the conservatory south, or within 20-30’ of south, to obtain the greatest solar heat gains. The conservatory should open off the living room and should not be obstructed by other buildings and extensions (see site layout section).

Increase the conservatory’s use as a buffer space by ensuring that it covers the maximum number of openings and the largest area of wall possible.

F i 2 2 a a n d 2 2 b ‘Sunspace’ type conservatories in housing at Gostwick, Peterborough. The windows between the living room and the sunspace can be opened on a sunny day to allow warmed air into the house. Heating energy requirement in these houses was reduced to 46% of a standard UK house


,

Safeguarding existing buildings

0 Use the conservatory to pre-heat incoming air, preferably by using natural ventilation. If warmed conservatory air is moved mechanically, more energy could be used than is gained.

they will overheat. 0 Ventilation and shading devices must be built into conservatories or

The large areas of glazing in conservatories pose a high risk of accident. Building Regulations require the glazing to comply with Approved Document M.

Safeguarding existing buildings 0 Site layout design should ensure that existing buildings, as well as the

new development, enjoy a reasonable standard of sunlighting. Sunlight to the main living room of a dwelling should be considered reasonable if it has a window facing within 90” of due south. This living room should receive at least one quarter of possible annual sunlight hours, including at least 5% of annual probable sunlight hours between September 21 and March 21 (see page 34). If this is not possible, then the living room should receive not less than 0.8 times the number of possible annual sunlight hours it would have received before the new development took place.

The sunlight penetration ‘before’ and ‘after’ can be predicted using the sunlight availability indicator in Site layout planningfor sunlight and daylight”.

0 For sunlight in existing gardens and amenity spaces use the following guideline: at least three-quarters of the garden or amenity area should receive some sunlight on March 21. If this is not possible the area which can receive sunlight should not be reduced (as a result of new development) to less than 0.8 of its former size. A solar altitude of 10” or less is excluded. These criteria should be applied flexibly to determine where sunlight is required in or around a building and to ensure that areas such as patios and conservatories are not overshadowed by new development.

it may be quickest to plot a shadow plan. (This illustrates the location of shadows at different times of day and year.)

0 When designing a passive solar building, anticipate the possibility that future development will block solar access and position the building(s) well back from the southern boundary of the site unless it is clear that no future development is to take place there.

0 For a large development which affects a number of existing properties,

On a solar estate there is the possibility that neighbours will block each other’s solar radiation by erecting large extensions and outbuildings. Guard against this by drawing up legal agreements which protect solar access for each property. This could be in terms of the winter solar radiation calculated by solar gain indicator or an estimate of as the number of hours of sunlight over a particular period.


Chapter 5

Orientation and daylight

r , PREVIOUS PAGE IS BUNK I


General requirements People value daylight in their homes. Good daylighting makes a room look lively and cheerful and also reduces the need for electric lighting. Conversely, people are unhappy with a gloomy room which does not have a reasonable view out, causing them to waste energy by switching on artificial lighting to ‘brighten it up’’’.

Site layout Space houses to reduce obstruction to daylight.

Existing buildings Ensure houses do not significantly obstruct the daylighting of nearby buildings.

Room depth and layout Ensure rooms are shallow enough to achieve good daylight penetration. Avoid creating areas which are permanently shadowed.

Windows Specify windows which are large enough to provide good daylighting to the interior as well as views out.

The quality of natural lighting can be improved if it enters a room from windows on more than one side. Walls can contribute to the quality of light by acting as reflectors.

Roof lights Roof lighting, area for area, usually admits more light than windows.

Site layout for good daylighting Reduce mutual obstruction by spacing-out buildings If houses are too close to each other, daylight entering the windows can be severely reduced. As a rule of thumb, the obstruction angle to the horizontal, measured in cross-section at a point 2 metres above ground level, should be less than 25” (Figure 24).

If obstructions are closer than this, they should not be continuous and enough daylight should be available from other directions. This may be checked by calculating the sky component on the window wall 2 metres above ground level, using the skylight indicator in Site layoutplanning for daylight and sunlight”. The sky component is the ratio of the amount of direct sky light falling on the outer face of the window to the amount measured on an unobstructed horizontal plane. A value of 27% or more corresponds to the recommended obstruction angle of 25” or less. Figure 24

BRE housing design handbook A?

-~


.''.... \ \

. ".. ., \ , " "

. ' .\ .. "

Figure 25

Check positions of trees Avoid siting trees close to and directly opposite windows, or avoid siting dwellings too close to existing trees. If trees are to be sited close to buildings, choose a deciduous variety without dense foliage16.20.

Limit self-inflicted overshadowing from protruding extensions or internal corners of courtyards Windows near projecting extensions or the internal corners of courtyards can be heavily obstructed. The 45" approach can be used as a check.

Figure 25 shows the application of the 45' approach to a domestic extension. Take the elevation of the window wall and draw diagonally down at an angle of 45" away from the near top corner of the extension. Then take the plan and draw diagonally back at an angle of 45" towards the window wall from the end of the extension. If the centre of a main window lies on the extension side of both these 45" lines, the extension may cause a significant reduction in the daylight received by the window.

This approach needs to be interpreted flexibly. For example, if the extension has a much larger building behind it, the daylight from that direction may be blocked anyway. If the extension has a pitched roof, the top of the extension can be taken as the height of its roof halfway along the slope. Special care needs to be taken in cases where there is an extension on the other side of the window, to avoid a 'tunnel effect'.

The 45" approach can also be used for courtyards. As a rule of thumb, if the length of a square courtyard is more' than 6 times its height above the 2 metre mark, ground floor windows facing the courtyard will receive enough daylight.


Interior day lighting

Interior daylighting To achieve good daylighting inside a building, three criteria must be satisfied.

Windows should be large enough 1 The overall level of daylight in a room is quantified using the average

daylight factor DF. It is given by:

WBT cyo DF= ~ ( i - R ~ )

In this equation W is the total glazed area of windows, A is the total area of all the room surfaces (ceiling, floor, walls and windows) and R their area-weighted average reflectance. Typically R = 0.5 for light coloured rooms, 0.3 for rooms with dark finishes. T is the glass transmission factor (0.85 for single glazing, 0.7 for double glazing and 8 the angle of visible sky (Figure 26). Where the obstructions are very complicated, an ‘equivalent 8’ can be calculated using the skylight indicator (Appendix A).

Recommended levels of average daylight factor DF are 2% for kitchens, 1.5% for living rooms and 1% for bedrooms (see BS 8206Part 2). The corresponding glazing area W for a particular DF can be found by rearranging the previous equation:

A(I - R ~ ) D F Glazing area W = 8T

Note that if there are windows in more than one wall, facing different obstructions, the average daylight factors due to each should be found separately, then added together. In this case the target glazing areas cannot be calculated simply; they can be found by trying different values in the first equation.

Minimise permanently shadowed areas 2 If a room is too deep, the back of the room will always look gloomy

compared with the area near the window, no matter how large the windows are. In houses, this usually only happens in rooms with windows in one wall only. The room is too deep if

Here I is the depth of the room from the window wall, w its width and h the height of the window head above the floor. RB is the average reflectance of the back half of the room, typically 0.5 for light finishes, 0.3 with darker finishes.

Note that light coloured rooms generally have a better daylight distribution as well as a higher average level of daylight.

Daylight distribution 3 The daylight distribution in a room may also be poor if it is heavily

obstructed. The worst problems occur when some parts of the room receive no direct light from the sky. The no sky line marks out these

from middle of window 4

Figure 26


. --


areas. Its position is found by drawing a line from the head of the obstruction through the head of the window (Figure 27). It is usually plotted at tabletop height (0.85 m). Areas beyond this no sky line will look gloomy and should be kept to a minimum by increasing the window head height, improving room layout or increasing the spacing between houses.

/

Section

Position of no sky line

1 Position of

This area cannot receive direct skylight

Figure 27

See References 21-23 for further information on daylighting.

View A view out should be provided in all rooms other than those where complete privacy is required (such as bathrooms and toilets). Most people prefer a view of a natural scene: trees, grass, plants and open space. A view allowing supervision of the immediate surroundings of the house is also required for security reasons.

The window should be wide enough to meet these needs.

Sills should normally be below the eye-level of seated people and window heads should be above the eye-level of people who are standing. Special consideration should be given to window heights in homes designed for elderly or disabled people.

The provision of a view needs to be balanced against the need for privacy and safety (see Chapter 9).


Protection of existing buildings

Protection of existing buildings Good site layout design will ensure that the new development receives enough daylight and that existing nearby buildings continue to enjoy a reasonable standard of natural lighting. In some cases this may have legal implications as well as being good practice generally. The following approach is suggested:

1 Ensure enough daylight still enters the windows of the existing building This can be done by adapting and applying the site layout guidelines for new buildings to each window of the existing building.

2 Check the daylighting distribution in the existing building This should not be made significantly worse by new houses opposite. To check this, draw the no sky line (at tabletop height 0.85 m) within the existing building (Figure 28), both with and without the new houses. Ideally the no sky line should not move; in this case the area which can receive direct sky light is unchanged. At worst, no more than 20% of this area should be lost in any one room.

3 Check that rights to light are unaffected Rights to light only apply in certain cases, usually where uninterrupted light has been enjoyed for 20 years or more.

The usual criterion employed in legal disputes is to plot the 0.2% sky factor contour on the working plane, using a special Waldram diagram. If over half the room has a sky factor below this level, the room as a whole is said to be poorly daylit. Any significant further encroachment of the 0.2% contour into the well lit fraction of the room is deemed to be actionable. This criterion is loosely related to movement of the no sky line, but it is not necessarily true that satisfying the guidelines above will prevent rights to light issues arising. See References 24, and 25 for further information.

fj@\ from existing window less

II

II

II

component more '

Figure 28


Chapter 6

Privacy and noise

PREVIOUS PAGE IS B ~ A N K ~

Privacy and noise

Introduction Noise is unwanted sound. It may be a steady background hum from a distant road, or the nearer sound from a neighbour’s hi-fi. People are usually more tolerant of noise when it comes from anonymous sources like traffic than they are of noise from identifiable sources like neighbours. Whatever the source, noise can be disturbing and ways of minimising it should be considered at an early stage of the planning process.

v---

Figure 29


Privacy and noise

Threshold 1 1 m o f pain

Jet engine 130

Microwave oven

e Figure 30 Noise levels

Figure 31 Quiet zone behind a barrier

Describing Noise units

noise

Noise level is usually measured in ‘A-weighted’ decibels (dB(A)). The ‘A’ weighting is an attempt to make the measuring instrument respond to sounds of different frequency (pitch) in the same way as the ear. Since most noises cover a wide range of frequencies the noise has to be broken down for detailed design work to show the energy in different frequency bands, usually 1/3 or one octave wide.

Steady noise levels can be read directly from a meter but, as most noises vary with time, special units have been developed to describe them. LA10,18h is used for road traffic and it shows the level exceeded for 10% o f the 18 hour measuring period. LAeq.~ is used to describe many types of noise and shows the level of an equivalent steady noise, measured over the same period of time (13, which must be stated.

Noise levels A change in level of 3 dB(A) will usually be noticeable, and a change of 10 dB(A) will correspond to a halving or doubling of loudness. Figure 30 gives a rough idea of the noise levels generated by different sources. These levels, with the exception of that of the jet engine, were measured in a room about 0.5 m from the source.

External noise control Site planning Department of the Environment Circular 10/73 Planning and noise26 contains advice on the type of development that is suitable for sites having different noise levels. BS 4142 gives advice on assessing the acceptability of noise in mixed industrial and residential areas.

The main sources of external noise are: road, air and rail traffic, industry and neighbours.

The designer should measure or estimate the noise level in the vicinity of each new noise-sensitive building. Noise from roads can be estimated using Calculation of road traffic noise27. Estimating noise from other sources is more difficult, and it may be easier to take measurements either at the site or at a similar one.

Noise from sources on the ground can be reduced by increasing the separation between the source and the building, but this is often impractical as the separation must be doubled to reduce the noise by 4 to 6 dB(A). Noise barriers (Figure 31) can reduce the noise by around 10 dB(A), but they must be:

0 imperforate.

0 close to either the source or the building,

0 as tall as possible, and

0 either longer than the building or returned at the ends.


Insulation against airborne noise

Barriers also protect gardens and open spaces and so have an advantage over improved facade insulation. Where aesthetic considerations are important, ‘green’ barriers can be made from a living willow frame with an earth core.

Sometimes a terrace of houses can be used as a ‘barrier block’ (Figure 32) to protect the rest of the site, but the design options for the dwellings within the barrier block may be rather limited, as less sensitive rooms must be on the ‘noisy’ side to act as a buffer.

Figure 32 Use of a barrier block

Insulation against airborne noise Insulation against external noise Most noise will enter traditional buildings through the windows, doors, ventilators, roof and chimney2*. The last two paths will be of more importance for aircraft noise than for ground-level sources.

It is very important to insulate windows because of their large area. Their insulation value depends on the source of noise. For traffic noise typical values for closed windows in dwellings are:

0 Single windows 28 dB(A)

0 Sealed double glazed units 33 dB(A)

0 Secondary windows 34 dB(A)

For aircraft noise, secondary windows provide about 3 dB(A) better insulation than sealed units.

A typical roof construction comprising tiles, a plasterboard ceiling and thermal insulation, will provide the same order of sound insulation as that for the sealed or secondary windows. This insulation can be improved by about 3 dB(A) by adding a further layer of 19 mm plasterboard to the ceiling. Other treatments must be designed so as not to reduce ventilation within the roof space.


~ -

Privacy and noise

Figure 33 Diagramatic section through rooms in a pair of flats separated by a floating concrete floor illustrating transmission paths for airborne sound. (Paths are reversed when the source is in the lower room.)

The insulation of a door is often limited by the seals, especially at the threshold. Where high insulation is required (>30 dB(A)), a lobby should be considered. When noise enters a room through more than one surface, the net insulation can be estimated taking account of the insulation and area of each surface28.

Insulating a building against noise also reduces ventilation. This may have to be restored by installing sound-attenuated ventilators to meet air quality and summer cooling requirements. Surveys show that occupiers like the option of opening their windows, even though this greatly reduces sound insulation.

lnsulation against internal noise within a dwelling Blockwork partitions provide better insulation than simple plasterboard on studwork types. In flats, light blockwork may reduce insulation vertically unless the floor is heavy (>365 kg/m2) concrete.

lnsulation against internal noise between dwellings The sound insulation of separating walls and floors is covered by Building Regulations Part E in England and Wales29, H in Scotland30 and G in Northern 1reland3l. The appropriate supporting documents give details of constructions likely to satisfy the,requirements. They describe a range of wall and floor types and also give details of suitable flanking constructions because, as Figure 33 shows, it is not sufficient to consider the wall or floor in isolation32~33.

The importance of good workmanship when filling perpends should be drawn to the attention of the builder by the designer.

Plumbing noises through a separating wall are often a source of complaint. However, noise can be reduced by positioning WC cisterns and other sources of noise away from the separating wall.

ise source

Flanking paths U

ti , /

I I 54 BRE housing design handbook

Insulation against impact noise

Points to remember

0 A wall separating two rectangular rooms will provide better insulation if it forms one of the short walls rather than one of the long ones.

0 Stepped or staggered layouts between dwellings improve insulation (Figure 34). It is good practice to arrange for rooms of similar function in blocks of flats to be juxtaposed at the separating wall, and to be vertically in line. Staircases and halls can provide barriers between living areas.

Insulation against impact noise Floors The main sources of impact noise are footsteps on floors and on stairs, and banging doors.

The Building R e g ~ l a t i o n s ~ ~ - ~ l describe three types of floor: solid concrete, concrete base with floating layer (concrete or timber), and timber (Figures 35 and 38).

Figure 34

For the solid concrete floor a soft covering is essential. Any type of carpet with underlay, or foam-backed material at least 4.5. mm thick should be suitable.

The performance of concrete base with floating screed floors often suffers if the resilient layer is damaged or bridged by concrete or by service pipes.

With a raft, cover the base with a levelling screed; this will seal it and provide a flat surface for the floating raft. Apply the ceiling finish directly to the concrete base; this is preferable to using plasterboard on battens.

For both concrete types, build the base into the walls on all four sides, but do not bridge the cavity.

For the timber floors, it is important to use the type of resilient material recommended in the Regulations because a lower density type may cause the performance to deteriorate when the floor is loaded with furniture. The floor may be supported around the perimeter by a batten, which should be fixed to the wall with a resilient strip on top.

Stairs Footsteps on stairs cause airborne and structure-borne noise which a soft covering on the treads will reduce. To further reduce structure-borne noise which travels to the house next door, build the staircase on the opposite side of the house to the separating wall. If the staircase has to be beside the separating wall, put the staircase for the adjacent house close to it so the hall provides a buffer zone.

Doors Less noise from banging doors will be transmitted to the adjoining house if the doors are in plasterboard rather than blockwork partitions (although


Privacy and noise

this will reduce privacy within the house). Resilient draught-proofing strips round the door frame will give a modest reduction. Provide mechanical closing devices for a more effective solution.

b 1-1 mF1 1-1 mm . .. ........ .... .... ....... . ..... . . ......... so!!. .overi!!s

1 base

a Solid base with soft covering

b Floating concrete screed

Resilient layer turned

c Floating timber raft

d Timber platform

Figure 35 Floors that reduce airborne and impact sound

Upgrading existing dwellings Timber intermediate floors Normal timber floors consisting of floorboarding on joists with a plasterboard ceiling have poor resistance to both airborne and impact sound transmission.

When converting traditionally built houses into flats, the existing timber intermediate floors will almost certainly need upgrading to provide an acceptable level of sound insulation between flats, as required by the Building Regulations.

IAdded ceiling

Figure 36 Timber floors; independent secondary ceiling added below existing structure

Figure 37 Addition of sound insulating materials above and below existing structure.


Upgrading existing dwellings

Strategies for upgrading The most effective way to reduce both airborne and impact sound transmission is to build an independent ceiling below the existing floor (Figure 36). Since this will lower the ceiling by up to 200 mm, it is necessary to check the existing headroom. If sufficient headroom is not available, use the approach shown in Figure 37. By raising the floor, this will reduce the headroom by about 70 mm. (Ensure first that the existing ceiling joists can carry the additional load.)

Figure 38 Concrete floors: Typical sound path via service duct Concrete floors

Concrete floors usually provide good sound insulation but problems may be caused by impact sound in the case of badly built floating floors and by airborne sound in the case of some pre-cast systems.

Problems usually arise from:

0 Air paths in the floor construction -especially in some precast beam- and-pot floor systems which d o not incorporate a wet topping

0 Large unfilled voids around service pipes going through the floor (Figure 38). These are usually hidden from direct view by lightweight Sound-absorbing quilt ducting hung against existing

wall (min 25 mm) 0 Flanking transmission along supporting walls

Repair strategy Timber stud work preferably fixed only to floor and ceiling 0 Fill all voids with fine concrete.

0 Fill residual service pipe voids with concrete after wrapping the pipe with mineral wool.

Masonry walls There are many causes of inadequate sound resistance in separating walls. Some of the more common causes are:

0 Separating walls of inadequate mass

0 Rigid ties in cavity separating walls

0 Lightweight flanking external walls

0 Unfilled perpends in masonry, particularly within floor zones and loft

Figure 39 Separating walls: new insulated stud wall constructed against existing wall

spaces

0 Joists built into the separating walls with inadequate beam filling

0 Deep chases for services cut back-to-back in the separating wall

0 Lack of dry packing under walls in concrete panel systems

between them

Strategies for upgrading Where the lack of sound insulation is due to the design of the separating wall, rather than to flanking paths, the following strategy may be effective.

Air paths allow sound transmission between dwellings

Erect a completely separate timber stud framework on one side of the wall with a sound-absorbing quilt between and with two layers of 12.5 mm

Figure 40 Separating walls: inadequate filling between joists provides sound paths


y- .

Privacy and noise

I ITEl E l

- __. - *

- >:

Er l 3-

1m1 Air paths blocked and

Additional plasterboard on ceiling on both sides of party wall

Figure 41 Separating walls: joists cut back and supported on hangers allow brickwork to be inserted to improve sound insulation

Lightweight wall I;_-I in loft spaces

Insulation batt fitted air path tightly between joists

Recessed switch and socket outlets back- to-back reduce sound

Figure 43 Separating walls: back-to-back electrical boxes may need relocating to eliminate sound paths

58

plasterboard fixed to the studs (Figure 39). Where space is at a premium, use proprietary partition systems provided the mass is not reduced.

If the joists are built into the separating wall, inadequate beam filling between the joists may cause air paths between dwellings (Figure 40).

In the worst situations cut back the joists and support them on joist hangers built into the separating wall. Brick up the redundant holes in the brickwork (Figure 41).

Sometimes the separating wall in the loft space is only a half brick thick. This provides adequate fire resistance but may be inadequate for sound insulation if it is not built well. It is usually impracticable to render this wall because of the proximity of the roof trusses. Sound insulation can best be improved by reducing transmission through the ceilings by adding an additional layer of plasterboard to the ceiling on either side of the wall (Figure 42).

The sound insulation of ceilings can also be upgraded a little by fitting dense mineral fibre batts between the ceiling joists (Figure 42). This is also effective against aircraft noise and doubles as thermal insulation.

On rare occasions, problems may be caused by excessive chasing of the wall for electrical services (Figure 43). In this case, the recessed switch and socket outlets may have to be changed for surface-mounted boxes and the chases filled with mortar.


.-

Chapter 7

Security

Security

Introduction The need for security has always had a major influence on the design of dwellings. The designer’s objectives, when planning a secure dwelling, are: detect, deter, delay and possibly detain the intruders.

This can be achieved by a combination of surveillance, physical security and electrical systems.

Burglary and vandalism present the main security risks for UK dwellings. There are approximately 500 000 recorded cases of burglary per year. This may be only a small proportion of the total number of burglaries committed. The British Crime Survey suggests the actual figure may be more than one million.

The risk of burglary varies according to the location of the dwelling. The highest risk (10% or more per year) occurs in flats, and housing in low- income areas. In typical suburban dwellings the risk is 1 to 3% per year.

Figure 44 ‘Avoid returning to a fortress mentality’

Fear of crime Statistics show that 3040% of residents in high-risk areas Iive in fear of burglary. This can cause occupiers to fit additional security devices or to seek a move to a ‘safer’ area. (This is especially the case in high-risk public sector housing). Incorporating security at the design stage can help to alleviate these fears and prevent a ‘fortress’ mentality.

The typical burglar Most burglaries are committed by opportunist thieves looking for easy pickings. The typical opportunist thief is likely to be a 12-18 year old male who lives locally. He will probably gain entry by an unlocked door or window. The opportunist thief will choose to rob a flat or house where he


Security

62

is unlikely to be detected. There is always an easier target in the next street. Opportunist thieves, however young, are ‘professional’ and can spot an obvious weakness in design and exploit it. The thief will probably prepare his escape route through a door, perhaps by turning the locking snib on a cylinder rim latch to play for time should the owner return unexpectedly.

Figure 45

Assess the risk Adopt a holistic approach to the design to achieve a balance between surveillance and physical measures and, where appropriate, intruder detector systems.

Design strategy Consult local police Crime Prevention and Architectural Liaison Officers on risks to be expected in that neighbourhood.

Security requirements can often conflict with safety requirements, such as ‘means of escape’ in fire, so they should be discussed with the building control and fire officers.

External layout Position outbuildings, fences etc to allow maximum surveillance of the approaches to the house and to minimise features which might provide a place of concealment or easy access to upper windows, balconies and other entry points. For flats, consider access by visitors and for deliveries of mail, milk, etc.

Physical measures 0 Select doors, windows, locks and other associated hardware that are of

appropriate strength and performance.

screws are of appropriate size. 0 Specify appropriate methods for fixing components, eg ensure that

0 Specify tamper-proof fixings if they are accessible from the outside.


Introduction

Provide appropriate concealed cabling or conduits and ensure any external cables are protected if an intruder alarm system or supplementary external lighting is to be installed.

Install trickle vents in windows which are likely to be locked in the closed position because of high security risk. Consider providing conduits to facilitate the later addition of an intruder alarm system, if not originally specified.

Check that the security provisions do not restrict means of escape during a fire.

Electrical measures Electrical measures include:

0 simple time-switched devices to operate internal lights when the house

0 manually or sensor-switched external lighting,

0 intruder alarm systems with local alarms, and

0 intruder alarm systems connected to a central monitoring station.

is unoccupied,

External lighting Properly sited and maintained external lighting, whether time-switched or sensor-operated, will act as a deterrent to a potential intruder. Position lights where they can cast a pool of light around front doors, windows etc, preferably at high level, where they are out of reach of intruders. Conceal cables to protect them from attack. Take care to position the fittings so that they do not allow shadows which could conceal an intruder or annoy neighbours, who may object to being awoken by badly positioned movement sensitive lights.

Intruder alarm systems Intruder alarm systems or burglar alarms should be seen as an addition to, rather than as a replacement for, other security measures. Intruder alarm systems can be local bell, sounder-only or can be connected to a central monitoring station. They can incorporate a range of detectors and sensors from simple micro-switches fitted to doors to infra-red or microwave detectors used for monitoring rooms. As with external lighting systems, intruder alarm systems can irritate neighbours because they often emit false alarms. Approximately 98% of all alarm calls are false and police authorities may refuse to respond to calls from centrally monitored systems owned by persistent offenders. Since the use of intruder alarm systems requires occupiers to follow strict setting procedures, they should be installed only after consultation with the future occupiers of the house, a competent installer and the police. (In some London Boroughs there is a requirement to register all alarm systems. This may become a requirement throughout the UK.) Where the future occupants of a potentially vulnerable dwelling are unknown, a concealed wiring or conduit network should be provided to allow the connection, with minimal disruption, of a range of intruder alarm systems (tailored to the occupiers’ needs and life-styles).


. . . -

Security

During construction 0 Fix all doors, windows and security hardware as specified.

0 Make provisions for the safe keeping of all keys and locks during construction. Hand all keys over to the occupiers on completion. If keys are missing, replace the locks.

0 On large sites, it may be prudent to specify locks with interchangeable cylinders. This enables locks with a common key to be used during construction and the cylinders and keys to be swapped for individual key sets at handover.

Because of the different risks and priorities involved, houses and flats will now be considered separately. Some points are common to both, so there is repetition of advice in both sections.

Houses External layout Risk There is a relatively high risk that thieves will gain access from a rear footpath - especially if this is adjacent to a public footpath and separated only by high screening.

External layout of the house and its surroundings can play an important role in security by providing a private or defensible space where the intruder is vulnerable and can be easily detected.

Figure 46

Apply the following criteria:

0 Provide surveillance by locating houses in groups.

0 Make the front door clearly visible from the street by avoiding alcoves

0 Build a well defined path from the front gate to the front door.

or recesses.

0 Build frontages in open view and restrict the height of walls and hedges.

0 Avoid high walls and fences in front of dwellings.


Doors and windows

However, the demands of privacy impose conflicting requirements, particularly in rear gardens. Planning requirements may also impose restrictions on the height and type of walls/fences on boundaries with public areas.

0 Build garages and parking spaces within the curtilage of the house and where they are overlooked from the house and surrounding houses.

If communal parking facilities are provided, they should be in well defined areas and open to surveillance.

0 Limit access to the rear of the house. Consider providing a strong lockable gate close to the house, set in a fencdwall high enough to deter climbing.

0 Ensure that rear gardens are surrounded by gardens of other houses, if

0 Ensure that the positioning of drain pipes and design features such as

possible.

porches, balconies and boundaries does not give easy access to upstairs windows and other entry paths.

0 Provide additional lighting at the front and rear doors and at garages if street lighting is inadequate.

This can be controlled by time switch, photo electric cell or passive infra-red detector.

0 Site facilities for external meter reading in full view of the street and not within the secure area of the dwelling.

Doors and windows Entrance doors All doors providing access to the dwelling, including doors between the dwelling and garages or other out-houses should be robust and capable of withstanding being kicked or charged. Doors in concealed positions, ie back doors or interconnecting doors, should be able to resist attack by tools; eg hammers, tyre levers etc. Entrance doors should meet the following requirements:

0 Wooden doors should be solid and a minimum of 44 mm thick.

0 Doors made from other materials should be strong and robust.

0 Entrance doors should be securely fixed to the frame by one and half pairs of steel hinges. They should incorporate one pair of hinge bolts, set between the hinges and be fitted with appropriate locks.

0 The frame and threshold should be securely fixed to the surroundings. Use a minimum number of fixing points of two per metre run of frame or threshold with a depth of penetration of the fixing screws or bolts into the sub frame of 100 mm or more.

0 Glass panels fitted to the door or adjacent to the door should be of a size, position or glass-type to prevent their being smashed to allow an intruder direct entry and to prevent manipulation of the locks or bolts fitted to the door.

0 All ironmongery must be fixed with screws of adequate size and length. 25 mm no 10 screws should be considered as the minimum.

0 Additional hinge bolts should be fitted where external hinges are fitted

~~

Figure 47


Security

Figure 48

Surface-mounted bolt

Mortice sashlock

Surface-mounted bolt

Figure 49

and the hinge pin is accessible from outside, eg on outward opening doors.

0 Metal reinforcement plates must be provided at appropriate places to

0 Consider fitting reinforcement plates at the following points to prevent

prevent jemmy attacks on locks.

splitting of the timber:

- around locks rebated into the door leaf - on the frame and door at the hinge points

This is particularly necessary for doors which may be subjected to prolonged and violent attack, eg back doors or interconnecting doors.

Front doors Front doors are the main entry and exit routes from a house and are normally the main escape route in an emergency. Provide front doors with:

0 A mortice deadlock operated from either side by only a key

0 A mortice lockset of the type used for doors to flats, ie operated by a

This should be considered in houses designed for use by elderly or disabled people, although it has the disadvantage of providing an easy escape route for an intruder.

0 A rim automatic deadlock

0 A door chain or limiter

0 A door viewer

0 A letter box, if a suitable position is not available near the main

It should be positioned at least 400 mm from any locks to prevent manipulation of the locks. Do not fit additional bolts to the main entrance door since they may delay escape of the occupants in an emergency.

handle or turn-knob instead of a key

entrance door

Other doors Other external doors do not normally need to perform as escape doors and can generally be secured from the inside before occupants leave the house.

Sliding patio doors are a common point of entry for intruders. Unless precautions are taken during fitting, it is comparatively easy to lever them out of their tracks.

Side, rear or interconnecting doors should be fitted with:

0 Mortice sashlock

0 Two or more surface-mounted or mortised bolts, preferably key- operated versions

Twin-leaf doors should be fitted with:

0 Mortice sashlock, preferably with a hook bolt

0 One pair of surface-mounted or mortice-type key-operated bolts to each door.

66 BRE housing design handbook -

Doors and windows

They should be fitted with:

0 Anti-lifting devices to prevent them from being levered out of their

0 A mortice hook bolt, with either a fixed guide pin or small dead bolt to

0 Either a pair of push-to-lock key-operated bolts or a multi-point

tracks

prevent the door from being lifted

locking system

Windows Windows and glazed doors are particularly vulnerable. The intruder can easily gain entry by breaking the glass, and opening unlocked windows and even the smallest opening light.

0 Glazed areas should be as large as possible. The noise created by breaking glass is a deterrent.

0 Avoid small opening lights which provide access to locks or catches on adjacent windows and doors.

0 Avoid louvre windows.

0 Use trickle ventilators to provide ventilation.

0 Install laminated glass on all vulnerable windows or glazed doors.

0 Install push button or automatic locks, which need a key to open them, on all opening windows. Since this may interfere with means of escape, the fire officer should be consulted.

0 Where an opening light forms part of a fire escape route, place a key in a suitable receptacle next to the window. Position the receptacle where it cannot be reached by an intruder through a broken window.

0 Ensure all glazing is firmly embedded in its frames. Ensure that external glazing beads are firmly fixed and cannot be levered free by a knife, screwdriver etc. It should be impossible to knock out internal beads by kicking, hammering or pushing on the glass.

0 Reinforce the framing sections of PVC-U or aluminium double or triple glazed windows next to the locking gear to prevent the frame from being deflected into the glazing cavity, allowing the lock to disengage. Alternatively, use a hook bolt or long throw bolt.

tamper-proof any fixings.

driven out on hinges which are accessible from the outside.

0 Fix frames adequately to the surroundings and conceal and make

0 When the window is closed, use hinge pins which cannot be removed or

Shutters or grilles Shutters or grilles fixed to downstairs windows or doors can provide an additional level of security. Since they can conflict with requirements for means of escape or access by the emergency services, they should be fitted only after discussions with Building Control Officers and the Fire Service.

0 Ensure that they may be opened rapidly from inside by the occupiers, especially where they cover an opening light, and that they are big enough to be used as a means of escape.

necessary. 0 Securely fix them in position with tamper-proof fixings, where


_-

Security

Electrical or electronic measures Electrical or electronic measures encompass a wide range of options, including:

0 Manually or sensor-switched external lighting

0 Simple time-switched devices to operate internal lights when the house

0 Intruder alarm systems with local alarms

0 Intruder alarm systems connected to a central station

is unoccupied

Since the use of intruder alarm systems requires occupiers to follow strict setting procedures, to minimise false alarms, they should be installed only after consultation with the future occupiers of the house, a competent installer and the police.

Where the future occupants of a potentially vulnerable dwelling are unknown, a concealed wiring or conduit network should be provided to allow the connection, with minimal disruption, of a range of intruder alarm systems (tailored to the occupiers needs and life-style) and conforming to BS 4737.

Flats The risks Flats or other multi-occupancy dwellings are several times more likely to be burgled, suffer from criminal damage, vandalism etc than equivalent individual houses. Flats in inner city areas and run-down council estates are particularly at risk, where the rate of attempted burglary is in the order of 1 in 10.

There are several reasons for this:

0 Surveillance is difficult in the semi-private or common spaces.

0 There are problems in distinguishing residents or legitimate visitors to the flats from opportunist thieves.

0 It is necessary to provide access for deliveries such as post, newspapers, etc and access for meter readers and maintenance staff.

0 The residents’ population tends to be made up of single people or childless families who are absent from the flats for long periods.

0 The regulatory and other requirements for means of escape in case of fire may restrict the extent of physical measures which can be applied to control access.

The problem should not be seen as one confined solely to flats in council estates, however. There is growing evidence that professional thieves are targeting blocks of flats built for sale. The thieves will monitor the occupants’ life-style and wait for them to go to work before gaining entry and burgling most of the flats in a block, within a few hours, with little chance of being seen or disturbed.

The security plan for all blocks of flats should be to reduce the risk to a level comparable with that for individual housing by increasing the level of surveillance in the common areas to that of an average street.


Flats

This can best be achieved by employing porters to control access, supported by closed circuit television (CCTV) etc. Unfortunately such measures are expensive and are only normally considered to be cost effective in larger blocks of flats where the costs can be spread over a large number of flats.

Alternative strategies are therefore required for blocks of flats which are low-rise, three to four storeys, and domestic-scale.

External layout As with individual houses, external layout plays an important role in security.

Create a clear boundary between the street and the ground the block of flats stands in by landscaping and planting to give clearly defined entrance paths for pedestrians and vehicle traffic, and by using different-coloured and textured surfaces.

Make the main entrance and any secondary entrances clearly visible from the street, with no alcoves or recesses.

Limit planting in height and position so as not to provide cover, but at the same time provide well-defined paths.

Garages or off-street parking should be within the curtilage of the flats and clearly visible from the street and flats.

The position of drain pipes, balconies, canopies should be considered to prevent easy access to upper floors.

Additional lighting should supplement street lighting at the main entrance, along paths and around parking and garage areas.

Access control __2_____2 Strategy The design of the main entrance door and adjacent lobby is crucial for controlling access to the block. Apart from the strategy for residents and their visitors, a strategy has to be developed to provide limited access for delivery staff (post, milk, newspapers etc and service staff, meter readers, maintenance staff etc).

Figure 50 Typical external layout

Since a porterkoncierge scheme would prove too expensive for small blocks of flats, the problems of how to provide limited access to public areas and a balance between residents’ convenience and their security and safety should be addressed at the early design stage.

The options are:

(a) Unlimited access to all the public areas

(b) Access for part of the day to all the public areas, with resident- controlled access at all other times

(c) Unlimited access to a foyer area incorporating delivery and meter reading points. Resident controlled access to all other areas

(d) Access for part of the day to a foyer area incorporating delivery and meter reading points. Resident-controlled access to the foyer at all other times, and to all areas at all times

Phone system linked

(e) Delivery and meter points outside the building. Resident-controlled Figure 51 Controlled foyer access to all areas at all times


Security

The most convenient and least secure option is (a). It should be considered only in community-type flats where a continuous resident presence is available to monitor deliveries etc, although there is a high level of risk.

Option (b) is convenient but carries a high security risk because intruders can easily mimic delivery staff; it only works well where deliveries and staff arc constant.

Options (c) and (d) are less convenient because residents have to make a journey or several journeys to the foyer to collect deliveries, but more secure because visitors are restricted.

Option (e) is inconvenient for the same reasons as options (c) and (d) but more secure overall, apart from the added risk to the external delivery points.

Appropriate security measures for each of these options are listed in the table below and discussed in detail in the following sections.

Access control option

Security measure a b c d e

Main door to block N R N R R Flat doors R R R R R Fire escape doors R R R R R Internal door to foyer N N R R N Entryphone N R R R R Meter and delivery points O O R R R Internal areas N R R R R

R = required; N = not required; 0 = optional

Internal areas Internal corridors and stairwells should be well-lit and should provide the minimum of nooks and crannies where an intruder can hide. Escape routes to emergency exits and fire escapes should be clearly marked and obvious. An escape route leading through a poorly used part of the block is unlikely to be used in an emergency.

Doors Main entrance door The main entrance door should:

0 Open outwards

0 Incorporate viewing panels to give a clear view in either direction

0 Be of substantial construction

0 Be hung with one and half pairs of hinges

0 Incorporate hinge-bolts with hinge guards and lock guards where necessary

0 Be fitted with a self-locking mortice lock, opened from the outside only by a key or electronic mechanism and from the inside by a simple push bar or handle, and be fail-safe in the unlocked position in case of emergency


0 Be fitted with a robust self-closing mechanism to ensure positive locking of the door after use

Where the main door forms part of a foyer system of access control, consideration should be given to constructing the door and adjacent walls entirely of glass of suitable strength. This has the advantage of giving maximum exposure to the foyer and its inner door, thereby improving the chances of detecting an intruder who may be attempting to break through the inner door.

Inner foyer doors Inner foyer doors should meet the requirements of the main entrance doors, and should conform to the requirements of the Building Regulations and BS 5588 with regard to fire resistance, means of escape etc.

Main doors to flats The main entrance door to individual flats requires special consideration (refer to BS 8220). Since it is often the only outside door, it has to provide:

0 A barrier to intruders

0 A means of escape for the occupants in an emergency

0 Access for the emergency services

0 On occasions a bamer to fire and smoke

In blocks of flats where there is no access control over visitors, this door may be the only physical security measure available to the residents. As such, it has to be capable of resisting prolonged attack by intruders using tools, but also satisfying the requirements for rapid entry from the Fire Services.

The London Fire Brigade and Civil Defence Authority require a door to be capable of being breached in less than three minutes using hand-held cutting tools. Police records indicate that doors in council estates, in this situation, have been subject to uninterrupted attack by intruders using sledge-hammers and Acrow props for periods of up to 30 minutes.

As a minimum, the doors and frame should be of substantial, unglazed wood or steel construction, to meet the requirements of BS 8220: Part 1. They must be fitted with:

0 One and half pairs of steel hinges

0 One pair of steel hinge bolts

0 An escape mortice lockset, preferably with a split-follower action

0 Hinge and lock guards

0 Doorviewer

0 Door chain or limiter

Using an escape mortice lock is recommended, since it needs to be locked with a key on leaving; this reduces the danger of accidentally locking a child in the flat. The lock can be opened quickly by a simple action from the inside without the use of a key. BRE and DOE believe this will meet the requirements of the England and Wales Building Regulations Part B

Figure 52

Reinforcement plates (door)

Reinforcement strips (frame)

Section through door and

Reinforcement Reinforcement plates (door)

\ \

Reinforcement strips (frame)

Figure 53

Figure 54


Security

with regard to ease of escape and the recommendations contained in BS 8220 for locks to doors of flats34.

Additional locks or bolts should not be fitted because they can delay escape in an emergency. If no form of access control to the block is being used, it may be possible, with the agreement of the building control and fire officers, to improve the security of the door when the flat is empty, by fitting additional locks which can only be locked from the outside.

Letter boxes should be positioned to prevent someone ‘fishing’ through the letter box to operate the door opening handle.

Entrance doors must also meet the fire resistance requirements of the Building Regulations. The complete door set, ie the door, frame and all fittings, should be assessed or tested against the appropriate fire resistance criteria.

Fire escape doors All doors on escape routes should meet the requirements of the Building Regulations. It should be possible to open security locks by a simple action in the direction of escape. Electronic locks should fail open in a power failure, or should have a manual override.

Where a final exit door, ie a door providing a means of escape from the building to the outside, is required to supplement the main entrance, it should:

0 Open outwards

0 Be of substantial construction, eg timber or steel

0 Be hung with one and a half pairs of hinges

0 Be fitted with hinge bolts, hinge and lock guard and a suitable escape

0 Not be openable from the outside by a key

lock or panic bolt

The positioning of the door is also important. It should provide access to a safe area away from the building but it should not encourage the residents to use it as an everyday exit from the building.

Windows Ground-floor windows, or those on upper floors which could be reached by means of external architectural features, should be fitted with suitable window locks.

Since upper-floor windows may form part of a fire escape route, a receptacle should be provided for the safe storage of keys for any window locks. This receptacle should be close to the window but hidden from external view.


Flats

Meter, delivery points and entryphones Lighting External areas surrounding the flats, especially paths and parking areas, should be well lit. Where street lighting is insufficient, additional lighting should be provided. The main entrance, foyer and all internal common spaces should be well lit.

Where internal or external light fittings could be prone to vandalism, anti- vandal fittings should be used.

Meter and delivery points Where a restricted access policy has been adopted, letter boxes, delivery points and remote meter reading points will have to be provided for each flat. These can be positioned on the external wall of the building or placed in the foyer. If positioned on the external wall, residents should be able to gain access to them from inside the building. Since allowing access to these points from both sides may provide a potential method of entry for an intruder, they must be designed and installed with great care. To prevent confusion, their function and the flat they service should be clearly identified. Letter boxes should be provided with a secure lock.

Electronics Entryphones The entryphone should be positioned close to the main entrance door. It should be:

0 Clearly visible

0 Of substantial construction

0 Firmly fixed in position using concealed or tamper-proof fkings

0 Positioned at a height suitable for use of the key pad and the audio link

0 Able to provide direct audio link between each flat and the entrance

All cabling junction boxes should be concealed and protected from attack or interference. The receiving end should be positioned close to the flat entrances.

Depending on the type of access control system adopted, consideration must be given to providing:

0 Automatic door release for each flat

0 An ovemde on the locking system for use by the emergency services

0 An override, with or without a time window, for deliveries, etc

0 A duplicate system on the inner foyer door

door

Where the entryphone system includes a closed circuit television camera link the following must be considered:

0 The type and position of the camera and the lighting of the entrance. These should provide occupants with an adequate view of the callers

0 Signal transmission to the flats via a separate video link or via the common television aerial

Figure 55


Figure 56

73

-

Security

The choice of system will depend on the degree of privacy/security required. Systems using the common aerial normally allow any resident to monitor all comings and goings. This can increase security but cases have been reported of residents taking advantage of the system to break into neighbours flats when they have gone out, or using it as an early warning system of the presence of police in the building.

Entryphones have sometimes been vandalised, perhaps because of insufficient tenant participation in the system. In some cases it has been necessary to introduce a concierge system with entryphones. The costs of the concierge can be partly offset by a saving on the costs of repairs.

Intruder alarm systems Intruder alarm systems may be an additional deterrent to an intruder, but they require careful design to be effective in flats, especially at entrance doors, lobbies and easily-accessible windows. Unless there is a resident caretaker a system relying on a local audible alarm, ie a sounder-only system, is unlikely to be effective; connection to a central monitoring system is therefore necessary. Systems for each individual flat may be more cost-effective if combined with a fire alarm system. To be effective the alarm system should be able to indicate which flat is the source of the alarm.


Chapter 8

Fire

Fire safety in dwellings

Introduction Development of fire In the early stages of a fire, the most important effects will usua j be those of smoke and other products of combustion. Often smoke will be the first evidence of fire detectable by the occupants and thus likely to be the first cause of alarm. When a fire occurs in an enclosed space, hot smoke-laden gases rise to form a layer which at first flows under the entire ceiling and then deepens to fill the whole space. When the smoke layer extends down to head height it will produce discomfort to the eyes and difficulty in breathing, both of which will interfere with the efforts of occupants to find their way towards the exits. People who are prevented from escaping by dense smoke, or who are unduly retarded by it from escaping, may suffer from the toxic effects of the products of combustion that accompany the smoke and the asphyxiant effect caused by lack of oxygen. Intoxication, incapacity, unconsciousness and possibly death may result. These

. considerations are particularly important when dealing with people who may vary widely in age and degree of mobility.

BS 5588:Part Appendix C

As the fire grows in area, the flames spread to nearby combustible furnishings, fittings, exposed papers, etc. The flames increase in height until they reach the ceiling where they are deflected horizontally and, radiating downwards, accelerate fire growth. If the ceiling is combustible it may ignite and add to the volume of flame and speed of fire growth. If the space has insufficient openings to provide a continuous air supply, the burning rate of the fire will diminish as it draws on increasingly vitiated products of combustion, but the gases generated will then be extremely toxic.

The effects of the fire may not always be confined to the space in which it originated. If the enclosing walls do not form a fire-tight joint with the floor (or ceiling) above, where the attack from the flames or hot gases is most severe, the fire will soon penetrate to the adjoining space. Even with fire-resisting construction the buoyancy and expansion of the fire gases can cause them to be driven out of the space to affect other parts of the building. If they penetrate into a vertical shaft, such as a stairwell, liftwell or duct, they will rise rapidly, attacking the top of the shaft and spreading elsewhere if there are any openings in the shaft. In such circumstances, if a substantial flow of air reaches the fire through a window or door, for example, the vertical shaft can act as a chimney and may greatly accelerate fire growth.

Smoke alarms Smoke alarms alert occupants by detecting fires at an early stage and sounding an alarm. If the occupants then take the correct course of action this will help in reducing injuries and deaths due to fires.

The designer should check that suitable mains-powered alarms (BS 5446 Part 1) are specified and that the plans show an appropriate location (BS 5839:Part 1). The guidance in BS 5839 is also given in a free Home Office

BRE housing design hundbook

1990

I 2 11 I PREVIOUS PAGE IS BLANK I I I

Fire

leaflet available from fire stations. The alarms must have a secondary power supply in case of mains power failure and be linked between floors so that all alarms sound when one detects smoke.

General The safety of people in case of fire is an overriding consideration for the designer Where is the fire likely to occur? 0 Anywhere in the dwelling 0 In the common part of the building 0 In an adjoining building 0 In a detached building in the near vicinity 0 In the open air within the vicinity

Who are vulnerable? 0 People of all ages and conditions most at risk are: 0 Very young children 0 The elderly 0 The infirm 0 The disabled 0 Those asleep 0 Firefighters 0 Rescuers

What regulations apply to the design and construction of dwellings? 0 The Building Regulations 1991 0 The Building Standards (Scotland) Regulations 1990 0 Building Regulations (Northern Ireland) 1990

To what dwellings do these regulations apply? 0 New buildings 0 Alterations to existing buildings 0 Conversion of existing non residential premises to form dwellings

Who enforces these regulations? 0 Building Control officers of local councils

Which part(s) of these regulations concern fire? 0 England and Wales - Part B 0 Scotland - Parts D and E 0 Northern Ireland - Parts E and EE

Which documents to use? 0 Building Regulations requirements for different parts of the UK are

slightly different. British Standard BS 5588 provides a common basis to which all the regulations relate; it applies to the whole of the UK, and is therefore adopted in this publication.


General

The fire can originate anywhere to threaten a person’s safety It may originate from: 0 an occupied room, or 0 an unoccupied room, or 0 a circulation area, or 0 within a concealed space.

BS 5588:Part 1:1990 Section 1 (3.1)

BS 5588:Part 1:1990 Section 1 (3.2) Within a dwelling, the fire can originate:

0 Within a room

0 In another room

0 Abovearoom

0 Belowaroom

From outside the dwelling the fire can originate:

BS 5588:Part 1:1990 Section 1 (3.3) 0 From within an adjoining dwelling

0 From outside an open-space or detached building

0 Above a flat or maisonette

Below a flat or maisonette Figure 57

To overcome the risks of fire the designer can use the following safeguards: Maisonettes

Houses andflats

BS 5588:Part 1:1990 Section 1 (3.4)

Automatic fire detection and alarm Structural fire barriers between dwellings Structural fire barriers between dwellings and common escape routes Structural fire barriers within dwellings Self-closing fire doors Selective positioning of rooms within dwellings Alternative exits and escape routes from rooms and dwellings Restriction of travel distance Provision for the control of smoke

0 0 0 0

0

0 0 0 0 0 0

0 0

0 0

Note: Structural fire precautions are required under Building Regulations.

BRE housing design handbook 79 -~~ .

Fire

Single-family dwelling houses only Provisions for means of escape and rescue will vary according to the height above the ground of the building's top floor

BS 55tBPart kl990 Section 2

Bungaiows and two-storey houses BS 5588:Part 1:1990 Section 2 (4.2)

Three-storey houses BS 5588:Part 1:1990 Section 2 (4.3)

Four-storey houses . BS 5588:Part 1:1990 Section 2 (4.4)

Any house with a basement BS 5588Part 1:1990 Section 2 (4.5)

*A room whose only escape route is through another room (this includes any-room on an open- plan upper floor).

. .

Fignre58d' .

Any inner room* is only used as habitable if it is provided with a door or window for access to exit.

Provide fire-resisting separation between top floor and lower floors and provide an alternative escape route; or provide a protected stairway connecting to all floors which either delivers directly'to a final

independent escape routes delivering to alternative final exits.

/ exit or affords access to at least two

No inner room* as habitable room allowed.


Provide an alternative escape route and separate the protected stairway from the lower storeys with a fire-resisting screen and door provided at or near landing level if alternative escape route involves using or crossing the stairway.

No inner room* as habitable room allowed.

Any inner room* is only used as habitable A if it is provided with a door or window for access to exit.

Provide a protected stairway connecting to all floors which either delivers directly to a final exit or affords access to at least two independent escape routes delivering to alternative final exits.

\

Provide an alternative escape route if a bedroom is in a basement. -


Single-family dwelling houses only

The design of doors and windows for escape and rescue purposes should have the following characteristics:

BS 5588:Part 1:1990 Section 2 (4.7)

(a) Window minimum unobstructed opening to be 850 mm x 500 mm

(b) Window sill height above floor to be between 600 mm and 1100 mm

(c) Distance between eaves along roof slope to sill of dormer window or rooflight = 1.5 m maximum

(d) Any door (including a french window or a patio window, above ground level, should lead to a balcony guarded with a protective barrier in accordance with BS 6180.

(e) The ground beneath the window or balcony should be clear of any obstructions and should be of a size and material suitable and safe for supporting a ladder.

Automatic fire detection and alarm should be provided

(a) Self-contained smoke alarms complying with BS 5446:Part 1 and installed as described in BS 5588:Part 1:1990 (appendix D: ref FB2 Smoke alarms in the home 1988, available from local fire authorities) or

BS 5839:Part 1. (b) a type L system designed and installed in accordance with

BS 5588:Part 19990 Section 2 (5.2)

House fitted with ducted warm air heating systems With this form of heating, precautions are necessary within any house having at least one of its floors situated more than 4.5 m above ground or access level, to avoid any risk that such a system would permit the spread of smoke or fire from rooms to the protected stairway.

BS 5588:Part 1:1990 Section 2 (6)

Refer to BS 5588:Part 1:1990 para (6.2) for recommendations.


. - ~-

Fire

BS 5588:Part k1990 Section 3 (9)

Flats on second floor and above entered at same level Section 3 (9.5)

First-floor flat entered at same level Section 3 (9.4)

Ground-floor flat entered at same level Section 3 (9.4)

Basement flat entered at same level Section 3 (9.3)

*A room whose only escape route is through another room (this includes any room on an open- plan upper floor).

Flats: internal planning No inner rooms* as habitable rooms allowed, and either: 0 provide an alternative exit and, if there

is no direct access to the entrance hall, provide a fire-resisting partition separating living and sleeping areas; or provide a protected entrance hall and limit travel distance from habitable rooms to the entrance door to 9 m maximum; or, for smaller flats and bed-sits, limit travel distance from any point in habitable rooms to the entrance door to 9 m maximum .and site cooking facilities away from the entrance door so as not to prejudice egress, and to safeguard the escape route.




If not provided with its own external entrance at basement level, provide an alternative exit. # .

82 B R E housing design handbook

P . _ _ _ - -~ -

Flats: internal planning

No inner rooms* as habitable rooms allowed, and either provide an alternative exit on the upper level or provide a protected landing, or, for smaller flats and bedsitting rooms, limit travel distance.

No inner rooms* as habitable rooms allowed, and provide an alternative exit on the lower level.

Additional considerations to those above:

(a) Travel distance limitations

(b) Position or separation of cooking facilities

(c) Siting and location of access stair

(d) Siting of any necessary alternative exit from a gallery

Alternative exits from flats (11.2) These should be sited remote from main entrance door and provided as shown above.

They should lead to final exit or common stair via:

(a) a door to access corridor, common balcony or deck at same level; or

(b) an internal private stair leading to an access corridor, common balcony or deck at another level; or

(c) a door on to an external stair; or

(d) a door on to an escape route across a flat roof leading to head of common/external stair.

BS 5588:Part 19990 Section 3 (9)

Flats on second floor and above entered from a floor below: BS 5588:Part 1:1990 Section 3 (9.6)

Flats on second floor and above entered from a floor above: BS 5588:Part 1:1990 Section 3 (9.7)

Flats with galleries: BS 5588:Part 1:1990 Section 3 (9.8)

BS 5588:Part 1:1990 Section 3 (11.2)

Figure 61

*A room whose only escape route is through another room (this includes any room on an open-plan upper floor).


Fire

BS 5588:Part 1:1990 Section 3 (10)

Entering at second floor or above into upper level of maisonette

BS 5588:Part 1:1990 Section 3 (10.4)

BS 5588:Part 1:1990 Section 3 (10.4)

Entering at first floor or above into lower level of maisonette

BS 5588:Part 1:1990 Section 3 (10.3)

Entering at ground floor into maisonette

Figure 62e

BS 5588:Part 1:1990 Section 3 (11.3) Alternative exits from maisonettes

(a) provided as shown above (b) should lead to final exit or common

stair to a place of safety via a door to access conidor, common balcony or deck, or

0 a stair separated by fire-resisting construction from rest of dwelling leading to an access corridor, common balcony or deck, or a door on to an external stair or a stair separated by fire-resisting construction from the rest of the dwelling, or a door on to an escape route across a flat roof leading to head of common/external stair.

Figure 63

*A room whose only escape route is through another room (this includes any room on an open plan upper floor).

Maisonettes: internal planning No inner rooms* as habitable rooms allowed on upper floor.

Either provide an alternative exit from each habitable room on the lower floor (if at above 4.5 m); or provide one alternative exit on the lower floor and provide a protected entrance hall and landing (if at above 4.5 m).

No inner rooms* as habitable rooms allowed on upper floor.

Either provide an alternative exit from each habitable room on the upper floor, or provide one alternative exit on the upper floor and provide a protected entrance hall and landing.

Any inner room* is used only as habitable if it is provided with a door or window for access to exit.


Flats and maisonettes

Flats and maisonettes Automatic fire detection and alarm Recommendations for flats and maisonettes needing protection

Mixed-user Normal Sheltered building use

Partly residential

Automatic fire detection and alarm equipment 0 0

Self-contained smoke alarms complying with BS 5446:Part 1 or A type L system designed and installed in accordance with BS 5839Part 1

0

0

Escape over a flat roof Refer to BS 5588:Part 1:1990 (11.4) for recommendations.

Doors and windows for escape or rescue (a) Window’s minimum unobstructed opening to be 850 mm x 500 mm*.

(b) A window sill height above floor to be between 600 mm and 1100 mm*.

(c) Any door (including a french window or a patio window) above ground level should lead to a balcony guarded with a protective barrier in accordance with BS 6180.

(d) The ground beneath the window or balcony should be clear of any obstructions and should be of a size and material suitable and safe for supporting a ladder.

(e) A door or window should not face onto an internal shaft or enclosure unless escape to a place of safety is possible without re-entering the building and there is sufficient space to bring in and safely erect a suitable ladder if escape or rescue would be from a room above ground level.

*These dimensions may be amended in forthcoming British Standards.

Ducted warm air heating systems within flats/maisonettes Refer to BS 5588:Part 1:1990 para (15.2) for recommendations.

Fire safety signs Consult with the fire authority to ensure that recommendations on exits are complied with.

Sheltered housing Special considerations are needed for:

(a) Planning within flats and maisonettes

(b) Escape routes from dwellings

BS 5588:Part 19990 Section 3 (8.2)

BS 5588:Part 1:1990 Section 3 (11.4)

BS 5588:Part 1:1990 Section 3 (11.5)

BS 5588:Part 1:1990 Section 3 (15)

BS 5588:Part 1:1990 Section 3 (16)

BS 5588:Part 1:1990 Section 3 (17)

(c) Communal areas


Fire

BS 5588:Part 1:1990 Section 3 (14.1)

BS 5588:Part 1:1990 Section 3 (14.2)

BS 5588:P.art 1:1990 Section 3 (14.3)

BS 5588:Part 1:1990 Section 3 (14.4)

BS 5588:Part 1:1990 Section 3 (14.5)

BS 5588:Part 1:1990 Section 3 (14.6)

Flats and maisonettes: beyond the dwelling Stairs and final exits Number and siting of common stairs (a) At least one common stair should be available to each storey.

(b) Additional common stairs are necessary to meet requirements for travel distance or for firefighting purposes (balcony/deck access) and afford alternative directions of travel from any dwelling served by stairs or via acceptable dead ends.

Width of common stairs 1 m minimum unobstructed width between walls (1.1 m minimum if a firefighting stair).

Enclosure of common stairs (a) Common stair should not connect directly with stores.

(b) If a common stair projects beyond, or is recessed from, the external enclosures to a building: (1) the distance between any opening in the external enclosures to the building and any opening in the enclosure to the stairway should not be less than 1.8 rn; (2) the enclosures within that distance and up to 9 m vertically below should be of fire-resisting construction that may have fixed fire-resisting glazed areas.

(c) Two adjoining stairs should be separated by imperforate construction.

(d) Access to any alternative escape route should not pass through a common stair en route to an alternative common stair.

(e) If a common stair forms part of the only escape route from a dwelling it should not be connected to any ancillary accommodation.

Basement stairs (a) If a common stair forms part of the only escape route from an upper

storey of a building (or part) it should not be continued down to serve any basement storey.

(b) If there is more than one common stair from an upper storey of a building (or part), at least one such stair serving the upper storeys of the building (or part) should be terminated at ground level; any other stair may connect with the basement storey(s) provided that it is separated from each basement level by a protected lobby.

Stairs within mixed-user developments Special considerations apply to mixed-user buildings. Refer to BS 5588:Part 1:1990 para 14.5.2 for recommendations.

Access lobbies and corridors to protected stairways Lobby protection to protected stairways is necessary to safeguard stairs serving dwellings which also connect with enclosed car parks, boiler rooms and similar risks. Refer to BS 5588:Part 1:1990 para 14.6.2 for recommendations.


Flats and maisonettes: beyond the dwelling

External stairs BS 5588:Part 1:1990 External stairs, whilst not desirable, may, in exceptional circumstances, be provided for small buildings or from storeys near to ground level or a roof or podium with its own escape route. Refer to BS 5588:Part 1:1990 para 14.7.2 for recommendations.

Section 3 (14.7)

Discharge from common stairs and final exits (a) No openings, doors etc in the separating element common to both exit

BS 5588:Part 1:1990 Section 3 (14.8)

passageways from two common stairs adjoining

(b) Any final exit to be immediately apparent for stairs serving storeys above and below the point of final exit

(c) Final exit sited to be clear of any risk from fire or smoke

(d) Boiler rooms and similar risks should not have any openings that would prejudice the means of escape from residential accommodation.

BRE housing desigii handbook

Fire - +

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Construction: all dwellings

Construction: all dwellings Construction BS 5588:Part 1:1990

The recommendations on the above pages are made on the assumption that the provisions for structural fire protection of any building complies with the appropriate building regulations.

Section 4

Structural fire protection measures depend upon: 0 Size of the building

Relation to the site boundary

0 Relation to other buildings on the same site

Structural fire protection embraces the following matters: Fire resistance of structural elements

Sub-division of building into compartments

0 Protection of all shafts connecting different compartments

Provision of cavity barriers and fire stops

0 Restriction of spread-of-flame on surfaces of wallskeilings

0 Construction of roofs and external walls

The provision of structural fire protection is intended to ensure that the building will not collapse prematurely in fire, that the occupants not at risk may safely remain in their dwellings, and that the means of escape will remain unaffected by fire for long enough to ensure that the escape of the occupants can take place without undue risk. It will not necessarily avoid the material loss of property.

AU dwellings BS 5588:Part 1:1990 0 Fire resistance BS 5588:Part 1:1990 section 4 (18.2)

Compartmentation (18.3)

0 Vertical shafts for lifts, hoists, services etc (18.4)

0 Glazed elements in partitions, doors and windows (18.5)

0 Fire doors (ie door leaf/leaves and door frame) (18.6)

0 Hold-open door systems for doors (18.7)

Section 4 (18.1)

0 Construction of escape routes (18.10)

0 Siting of gas and electricity meters (18.14)

Flats and maisonettes 0 Entrance and alternative exit doors

0 Doors on escape routes

0 Common stairs

0 Ladders

0 Lift machine rooms

Refer to BS 5588:Part 1:1990 (18.8) Section 4 for recommendations (18.9)

(18.11)

(18.12)

(18.13)


Chapter 9

Safety

Safety

Introduction User space related to safety Human error and bad design are the main causes of accidents. Many accidents could be avoided by improving design.

The under-fives and the over sixty-fives are most vulnerable to accidents in the home; usually as the result of a fall. A similar event may be a minor mishap for an active adult, but fatal to an elderly person. Good design will help to reduce the strain on people (caused by bad design) that can lead to accidents. Safety must be considered as a permanent factor of design if the likelihood of accidents in the home is to be reduced.

Note: design which is suitable for disabled or elderly people will usually be much safer for the general population.

Stairs and circulation areas Private stairs Stairs and landings should be well lit with no unexpected changes of direction or pitch. Landings should be not less than the full width of the stairs. Stair risers and treads should be not more than 220 mm high and the treads not less than 22 mm deep. The pitch should be less than or equal to 42 degrees. (Experiments carried out at Loughborough in 1966, showed that elderly people preferred deep treads, even if this meant increasing the riser height).

Figure 64

Stairs with minimum headroom and height of handrail // Continue the handrail beyond the lowest riser to provide a support at a crucial point on the stair. A handrail which terminates abruptly or changes in level or pitch could cause a person to lose balance and fall. There should /

/ minimum be a strongly-fixed continuous handrail on at least one side of the stair, of a shape and size which can comfortably be gripped.

/ /

/ /

Single steps 900- 1000 mm

If a single step is isolated from any other change of level or occurs in an unexpected place, it is likely to cause a fall. Where a change of level is expected, at thresholds or entrances to buildings, it is not dangerous. A single step which already exists can be made safer by a definite change of colour and a good light. Provide an adjacent handrail to indicate a change in level.

Clearance To allow for the movement of furniture, BS 5395 calls for a clearance of not less than 1.5 metres between the pitch line and any bulkhead slope. Figure 65

BRE housing design handbook I PRNIOUS PAGE IS BLANK I 93 .

- _ _ - - -

Safety

Figure 66

Figure 67

Balustrade If there is any gap wider than a child's head between railings there is a danger that the child may trap his or her head or climb through the gap. Building Regulations call for a maximum gap of 100 mm. Allowing for construction tolerances, a target spacing of somewhat less than 100 mm is suggested.

Winders and spiral stairs Winders are frequently used in tight planning situations. The design of winders and spiral stairs is covered in British Standards 5395 and BS 585.

Top and bottom steps If top or bottom steps of a flight encroach upon the landing, people may fall down the stairs or trip over a projecting step.

Open risers A stair with open risers has special hazards which may affect some users more than others. Building Regulations provide for a maximum gap where the stair is used by children, but older people may feel uncomfortable and insecure from being able to see through the open spaces.

Lighting The position of light fittings on stairs is very important. Light should shine towards the stairs so that people descending the stairs can see their way clearly without casting shadows in front of them. Two-way switches should be used at top and bottom of the flight. Lighting fittings and windows on stairs should be within normal reach: otherwise changing the bulb or cleaning the window may be a dangerous job.

Doors in circulation spaces A door which opens outwards into a landing or hall, or swings so as to obstruct the top and bottom of the stairs, might collide with people passing. This also applies to cupboard doors.

Figure 68


I

Doors

Doors Thresholds With the increase of factory-made building components, thresholds to internal doors are likely to become more common. These are potentially dangerous and should be tapered off unless a fitted carpet is used each side of them. A threshold associated with a change of level is not so dangerous because the change is expected. A projecting step at the bottom of a flight may also cause a fall.

Mat wells Mat wells are needed at entrance doors to keep doormats flush with the floor.

Floor finish A slip-resistant floor finish is important in circulation areas where people are in a hurry, especially when they are going from one level to another and making sudden turns. Floors near entrance doors may get wet from people’s shoes. Materials which become slippery when wet should not be used where wet conditions may occur.

Glazed doors Glazing in doors is covered by Approved Document N of the Building Regulations which requires that glass in critical locations should either:

0 break safely,

0 be robust or in small panes, or

0 be permanently protected.

The critical areas which are defined by the Building Regulations are illustrated below.

If a door is glazed to the floor people may try to walk through it. Obscured glass or a guard rail will help to make the door obvious (although this is not strictly a requirement under Clause N2 of the Building Regulations with respect to dwellings).

Glass in doors obviously has to be strong enough to withstand everyday use and slamming. Toughened or laminated glass may need to be used in glazed doors in some cases.

Glazing at low level is always a danger for a child or adult who falls over. Glazed doors should never be put at the bottom of stairs.


Figure 69

A threshold forming the nosing of the step IS safer than one which IS set back.

Bad: door opens

Good: door opens outwards

Figure 70

77

I I I 300rnn

Figure 71

95 7 -.

I

Safety

Figure 72 Care is needed with pivot hinges to avoid hazards - especially where young children are concerned

\ Figure 73 A swing door glazed enough for anyone on the other side to be seen and with a guard rail

Floors Floor finishes Most floorings when dry have adequate slip resistance, but many smooth floorings can become dangerously slippery when wet. For floors in kitchens and food preparation areas (which are often wet) and where textured finishes have been specified, there needs to be a trade-off between ease of cleaning and slip-resistance. However, uneven or slippery floors make every activity potentially dangerous. Floor finishes near doors are discussed on page 95.

Durability and slip-resistant performance - the chief safety factors - have to be considered in relation to how the floor will be used; for example, rubber flooring, which has good non-slip qualities when dry, is very slippery when wet and therefore quite unsuitable for washing or cooking areas.

Durability is affected by the care and skill with which the floor is laid, the behaviour of the sub-floor and by the choice of material itself. Failure to provide adequate damp-proofing and ventilation or a proper sound screed can lead to serious deterioration in finish, such as buckling of wood block floors or loss of adhesion in tiled finishes.

Non-slip performance is also bound up with maintenance - an aspect which it is impossible for the designer to control. Both dirt accumulation and polish can make a floor dangerously slippery. Unfortunately many people involved in the cleaning process associate a high degree of polish with cleanliness.

Certain synthetic sealers are specially formulated to provide slip resistance for floors. Polishes made from soft waxes tend to make hard floors more slippery.


Floors

Table of floor finishes and coverings, external and internal ~~

Slip resistance in wet

Material conditions Notes on use

Carpet VG Installation should be to BS 5325. Where carpet adjoins a different floor finish at doorways, a dividing strip or threshold should be provided.

*Clay tiles G-F Installation should be to BS 5385:Part 3. Poor when polished.

*Clay tiles - VG-F textured finish

Suitable for external stairs or steps. Panelled finish easier to clean than ribbed. Tiles are also available with a carborundum finish, which may be useful in kitchens and food preparation areas.

Concrete G

*Concrete paving G slabs and concrete paviors

Linoleum VG-G

Cork tiles VG

Flexible PVC VG-G

Felt-backed VG-G flexible PVC

Flexible PVC inc. VG non-slip granules

*Granolithic G

Rubber - sheet or VP tiles

*Terrazzo G

Timber - softwood G boards or blocks

Timber - hardwood F boards or blocks

Key: *Slippery when wax polished VG - verygood

F - fair G - good

Installation should be to BS 8204:Part 2. Slippery when wet unless a textured finish is applied or slip resistant aggregate used.

‘Ripple finish’ is slip resistant even when wet. Slabs available with carborundum or other non-slip finish.

Susceptible to damp. Can be slippery with waxed finishes.

Susceptible to damp.

Slippery when wet, unless textured. Susceptible to damp. Sheets liable to come up at edges, making a tripping edge if not fixed to base.

Susceptible to damp; slippery when wet unless textured.

Fairly slip resistant even when wet. Hessian-backed types are susceptible to damp.

Installation should be to BS 8204:Part 2. Can be poor when wet. On external steps a carborundum finish should be specified.

Unsuitable for areas connected with cooking, washing or laundering or in spaces near entrance doors. Very poor when wet.

Exceptionally slippery when wax polished. Polish should be avoided on surfaces adjacent to terrazzo as it can be transferred by treading. On stairs slip resistant nosing is necessary.

Can be poor if wax-polished.

Can be very poor if wax-polished. On stair treads a slip resistant nosing is necessary.


- \--

Safety

- __ Figure 74a A projected floor slab

Windows Ways to avoid vertigo The lowest part of a window should not be less than 800 mm above the floor, otherwise it should be guarded at least to that height.

To prevent contact with low level glazing, the Building Regulations Approved Document N requires that a sphere of 75 mm diameter should be prevented from contacting the glazing. In addition, all guarding should be robust and difficult to climb.

Windows need to open out for reasons of weatherproofing. Paths should therefore be kept clear of buildings wherever possible.

Maximum downward reach for cleaning fixed light 550 mm

Maximum downward reach for cleaning fixed light 550 mm, so area below 494 mm above floor level is not cleanable

I Safety rail

I

Figure 74b A solid upstand under the window

Figure 74c A substantial salcty rail as part of thc window dcsign

Figure 74d Suggested ways of providing a safety Figure 74e Safety rail rail at recommended height

98

Figure 74f Danger of collision from projecting windows


Windows

Cleaning windows Wherever possible, in dwellings, provision should be made for cleaning windows from the inside of the building.

BS 8213:Part 1:1991 Code of Practice for safety in use and during cleaning of windows and doors, contains appropriate recommendations. Some points to remember are shown here.

E

- - AU these risks are increased when working from steps, so tbe designer should bear this in mind when spedfying windows above normal arm reach from a standing position on the floor.

_ L - - .._- - - -.- - - _ - _ _ - - - _ _ I - -

Figure 7% Fixed equipment below a window restricts the reach for cleaning

Figure 7% Difficulty of cleaning a horizontally pivoting window if it is not reversible through 180'

Figure 75c The easiest way of cleaning sash windows, by sitting on the sill, has obvious risks. The designer should bear this in mind when specifying sash windows, or perhaps the design of the sill could be such as to obviate the practice.

U \\ I

Figure 75f Difficulty of cleaning a fixed vertical light above a pivot window

3

Figure 75a Maximum arm and shoulder reach for cleaning windows - 850 rnm

Figure 75d Difficulty of cleaning an extended window if it is too deep

\

Figure 75g Difficulty of cleaning a fixed light next to horizontal pivot window

BRE housing design handbook 99 I -

Safety

100

Height of window controls

-

1.7 m

Figure 76a Suggested comfortable vertical reach over a 600 mm wide worktop

2 m

Figure 76b Maximum vertical reach further than is desirable


Check-list on safety

Check-list on safety Food preparation

Provide an uninterrupted sequence of work surface/cooker/work surfacelsinklwork surface in the kitchen working area, near storage and eating areas. Do not place the cooker immediately next to a window or door. Place doors to the kitchen where they will minimise through-traffic. Plan the swings of all doors and cupboard doors to avoid collision. Make the worktop the same height as the boiling-plate or rings. Do not fix a ceiling-mounted airer or a cupboard directly over the cooker or boiler. Light working areas so that shadows are avoided. Provide storage space within normal reach for all articles in daily use. Provide adequate and conveniently located power points at worktop height.

Laundry In the clothes washing area, provide: 10 Safe heating 11 Hotwater 12 Adjustable ventilation 13 Floors which are slip-resistant under wet conditions 14 Drying and airing facilities

Artificial lighting 15 Position switches and socket outlets with safety in mind. 16 Provide artificial light for the roof space with a switch at the access.

Use an indicator light to show when the light is on, to avoid it being left on for long periods.

17 Provide a light by each bed. 18 Place light switches between bedroom and WC so that the way ahead

can be lit from either direction. Pull-switches in bathrooms and WCs should be low enough for a child to reach.

19 Use illuminated switches in circulation areas.

Water storage 20 Fit secure covers on water tanks and butts. 21 Insulate cold water storage to maintain temperatures below the levels

at which legionella proliferates. 22 Ensure hot water storage tanks can be heated to over 65°C to kill off

legionella.

Bathrooms 23 Position switches and earth electrical equipment in strict adherence to

IEE (Institution of Electrical Engineers) Regulations. 24 Ensure that space heating for the bathroom is safe. 25 Store medicines in a lockable cupboard out of small children’s reach. 26 Provide a bath with flat bottom and grab rail or other device for

steadying the balance. 27 Ensure that the bathroom floor is slip-resistant in wet conditions. 28 Ensure that locks on WC and bathroom doors can be opened from

outside in an emergency.

BRE housing design handbook 101 - -

Stairs 29 Make fixed handrail continuous on at least one side of staircase. 30 Do not allow gaps of more than 100 mm between balustrades or

railings or between riser and tread in open riser stairs. 31 Avoid single steps. If unavoidable, differentiate by change of colour. 32 Ensure that tapered steps meet the requirements of BS 585:Part 1. 33 Winders should not be the first choice in design. If unavoidable,

position them at the bottom of the stairs. 34 Do not allow top and bottom steps of a flight to encroach on

circulation areas. 35 Avoid open risers on stairs which will be used by the young and the

elderly. 36 Ensure that artificial lighting shines towards stairs to prevent shadows. 37 Place windows and light fittings on stairs within normal reach.

Circulation and access 38 Avoid placing doors or cupboard doors where they can obstruct

circulation spaces. 39 Detail thresholds to internal doors to minimise tripping. 40 Use special detailing for off-centre pivot doors to avoid trapped

fingers. Glaze swing doors so that people approaching from the other side can be seen.

41 Clearly indicate where doors and panels are glazed to the floor, eg by the use of obscured glass.

42 Make glazing in doors strong enough to withstand slamming, and use toughened or laminated glass to protect the user in case of fracture.

43 Ensure that floor finishes in circulation areas and near entrances are slip-resistant, especially in wet conditions.

44 Provide mat wells at entrance doors. 45 Design thresholds to form the nosings of steps rather than occur on a

flat floor. 46 Design the dimensions of external steps to give easy going, but avoid

shallow steps less than 75 mm. 47 Avoid single external steps and unexpected ramps. If unavoidable,

they should be conspicuously marked by a change of colour or material or a handrail.

48 Ensure that ramps and open access stairways are slip-resistant under both wet and dry conditions. Use canopies to protect against wet and freezing conditions.

49 Avoid open stairwells. If unavoidable, make the balustrade unclimbable.

50 Ensure there is no change of level between the lift and the flat entrance door in blocks of flats.

51 Balcony railings should be unclimbable and bulky enough to give reassurance. There should be no room for a small child’s head or toes between the members of balustrades.

External works 52 Keep paths away from buildings by a separating strip which is uncomfortable

for walking on. This will also keep pedestrians away from open windows. 53 Ensure that paths used at night are well lit. 54 Make fences and gates difficult for small children to climb or open. 55 Make very low fences clearly visible. 56 Provide falls and drainage to paths, steps etc which are exposed to the

weather.


Service installations 57 Follow IEE Regulations. 58 Fix meters, main switches and fuse boxes within normal reach,

preferably near the entrance. 59 Follow British Standard Codes of Practice for gas installations.

Check-list on safety

Heating 60 Do not fit fixed radiant fires in small rooms unless they are fitted at

high level. 61 Provide a permanent fixing for an open fire to allow a guard of

standard design to be installed. The edge of the hearth should be raised. Avoid mantelshelves above an open fireplace.

Windows 62 Use child-proof fastenings to casement and pivot windows above

ground level which limit the initial opening to 100 mrn. Beyond 100 mm they must allow continuous control of the window's movement to prevent swinging in high winds. Use of such fastenings above third floor level is mandatory.

63 Ensure that stair windows are within normal reach for cleaning and opening.

64 Specify glass in accordance with BS 6262 or with Building Regulations Approved Document N.

65 Ensure that side-hung casements have easy-clean hinges with a clearance of 100 mm minimum.

66 Ensure that windows above third storey height (and also below this height where access for ladders is not convenient) can be cleaned and re-glazed (though not necessarily repainted) from inside, unless there are balconies.

67 Ensure that stair windows which are cleaned by contract have no opening lights lower than 1.12 m from the floor and are fitted with budget locks, preferably with a visual indication whether the lock is open or shut.

approximately 180" so that they can be cleaned entirely from inside. A fixed light below the safety level of 1.12 m must not extend beyond 610 mm because of cleaning difficulties.

69 Ensure that windows which are reversible for cleaning have locking bolts to fix them in the fully reversed position. Use independent fastenings at each side of such windows, far enough apart to be beyond a child's reach.

70 Do not exceed a height of 2 m for hand-operated controls. This height should be reduced if there are fixed obstructions below the window.

68 Make windows and high-level glazed vents reversible through

B R E hoiising design handbook 103

Chapter 10

Energy efficient design

I PREVIOUS PAGE IS B M N K ~


Introduction Energy efficiency The importance of energy efficient design has been recognised increasingly over the years as the issues of the ‘energy crisis’, affordable heating and the increasing ‘greenhouse effect’ have become apparent.

Energy used in dwellings accounts for about 30% of all energy consumed in the United Kingdom and a similar proportion of energy-related emissions of carbon dioxide to the atmosphere. The average household spends 6% of its total annual expenditure on domestic energy.

Energy efficiency for individual dwellings can be measured in terms of the amount of energy needed to produce a given performance. So an energy- efficient house is one which needs less energy than other houses of a similar size to meet the occupants needs. This definition allows quantitative comparisons to be made between different dwellings and changes to the performance of the dwelling stock to be measured.

In assessing energy efficiency, two issues must be considered:

1 Defining the required levels of service The ways in which householders use their homes vary widely, leading to large variations in the amounts of energy they consume. It is often convenient to standardise needs, based on typical households with carefully defined living patterns. For space heating, indoor temperatures and heating patterns can be so defined that heating energy requirements can be calculated or measured. Other uses of energy can be based on average consumption derived from measurements and surveys, or by identifying the appliances used.

2 Expressing energy needs Annual energy cost is often the most appropriate measure of energy needs because it allows energy to be assessed on the same basis as other costs and is most meaningful to the consumer. Since prices can change fairly quickly, energy units may be a more satisfactory basis for assessing long-term change if only one fuel is being considered.

BRE housing design handbook I PREVIOUS PAGE IS BLANK 1


Terms used to quantify energy Primary energy - the energy content of fueLentering the energy economy Primary energy represents: the energy content of fuel input to power stations, oil refineries, processing solid fuel, etc; energy used during extraction of the fuel itself; losses in distribution networks; and the energy delivered to users.

Delivered ene& - the energy content of fuel delivered to the consumer For space heating, it is the energy input to the heating system.

Useful energy - the energy re the poiqt of application 1 ~

perform a specific function at

tput of the heating system.

unit of energy. Because of the energy requirements of a

typical household, the GIGAJOULE (GJ) is used. Other familiar units of-energy are the eKILOWATT HOUR (used for electricity).

1GJ = logjoules = 278 'kilowatt hours = 9.48therms

The WATTls the basic unit of POW

_-

Factors affecting energy efficiency Heat losses When a building is heated, indoor temperature is higher than outdoor temperature and heat is lost by conduction through the fabric of the building. The fabric heat loss rate is measured in terms of heat flow in watts per degree of temperature difference between indoors and outdoors (W/K). Heat is also lost through the replacement of heated air by fresh air drawn from outdoors. The amount of air involved is the product of the internal volume of the building and the rate at which air is replaced. This rate includes adventitious ventilation, or infiltration, as well as deliberate ventilation by the use of windows, extract fans etc. The ventilation heat loss rate, like fabric lieat loss rate, is measured in W/K. Fabric and ventilation heat loss rates together make up the specific heat loss rate; this is a good measure of the thermal performance of the building and gives one basis €or comparing its performance with other buildings of similar size.

Heating system efficiency The efficiency of a heating system is the ratio of the energy it produces to that which it consumes; it is usually expressed as a percentage. It can vary widely and has a strong effect on fuel consumption. The benefits of good insulation can be offset by an inefficient heating system while, conversely, a hard-to-heat building can benefit greatly from the installation of a highly


Factors affecting energy efficiency

efficient system. A calculation of running cost allows investment in an improved system to be compared with investment in better insulation and the most cost-effective combination of measures to be selected. The controls fitted to a heating system are also important because they affect both the efficiency of the system and the extent to which it matches the requirements of the occupants.

Internal heat gains Many of the heat gains in dwellings are by-products of activities such as cooking, water heating and the use of electrical appliances. In these cases, energy efficiency considerations dictate that the appliances themselves should be made more efficient. This will, of course, reduce the heat gains and thereby give a marginal increase in the need for space heating. It will have a beneficial overall effect since not all of the gains (many of which occur at times when no heat is needed) will contribute usefully to heating, Moreover, electrical appliances mainly use full tariff electricity which is likely to be much more expensive than the fuel used for space heating.

Solar heat gain is not the result of other energy use and should, therefore, be made as large as possible when space heating is required. Benefit from solar heat gain is determined by the design and orientation of the dwelling as well as the climate and passive solar design sets out to make the best use of these (see Chapter 4.)

Although heat gains should be taken into account when calculating annual energy needs, they should not be considered when sizing a heating system for maximum demand as there will be times when heating is required and gains are at a low level.

Fuel cost The cost of heat, light and power is important for the householder. Clearly the unit cost of the fuel affects this directly and is as important as the physical factors that affect the need for energy. This issue is partly obscured from the layman by the different units used by the fuel industries as their basis for charging.

Electric storage heaters take advantage of off-peak tariffs. It is usual to design systems based on storage heaters so that they are able to meet some of the heating needs by using electricity at the off-peak rate. In practice, the proportion of electricity actually consumed at off-peak rate can vary quite widely according to the way the heating is used, but 90% is a good guide for systems which are designed and used for whole house heating. Systems used for heating only part of a house generally require a greater proportion at peak rate.

Changing the fuel or tariff can sometimes be the most effective improvement. For example, a change of electricity tariff to the off-peak rate can often make a large reduction to space and water heating costs. The benefit from fuel changing must also be considered in the context of the price stability of the fuels in question. In the past decade, oil has varied from being one of the most costly to one of the cheapest fuels available. Coal prices have been more stable but vary considerably with region, being lower in mining areas. Change of fuel, unless accompanied by other measures, may not lead to fuel saving, since the fuel may still be used inefficiently.

BRE housing design handbook 109 ~


110

Calculating energy requirements Calculations of energy requirements in dwellings are normally based on measurements of the consumption patterns of a variety of households in similar circumstances.

Although actual consumption varies considerably between households, even when they occupy similar dwellings, it is practicable to estimate energy needs for a given pattern of use for both new housing and existing housing.

Domestic energy calculations must take account of many factors:

Climate

The physical characteristics of the dwelling and its heating system

0 The way in which the house is used, including the extent of space and water heating

0 Internal temperature and the use of domestic appliances

Figure 77 shows the main flows of energy into and out of a typical house. Note that the heating system is not the only contributor to space heating. Even in a house with average standards of insulation, solar and internal gains supply a significant proportion of the space heating needs.

Figure 77

Traditionally, calculation methods have usually concentrated on heat losses and have ignored heat gains. (See pages 157-158). This meant that they were suitable for estimating the maximum loads to be met by heating systems but were poor at estimating annual energy needs. The BRE Domestic Energy Model (BREDEM)35 has been developed to make realistic estimates of annual needs simply and conveniently. BREDEM is based on experience gained from measurements made in a large number of occupied dwellings and the results of research into many aspects of dwelling design which relate to energy use.

Figure 78 shows the results of some BREDEM calculations on a semi- detached house, illustrating how energy costs vary with insulation levels.

B R E housing design handbook

Calculating energy requirements

0

It shows that space heating costs dominate if the house is poorly insulated but are greatly reduced with better insulation. In very well insulated dwellings, only a small proportion of energy is used for space heating.

Standing charges 1 I I I

Microcomputer versions based on BREDEM allow rapid assessment of designs and changes in designs, and are invaluable in deciding on the most cost effective energy features.

600 House eoorlv insulated

Cooking, lights and appliances 100 L

Figure 78 Typical breakdown of energy costs in well and poorly insulated dwellings.

Information Paper IP13/8836 describes a worksheet version of BREDEM which can be operated using either a hand-held calculator or a personal computer. It includes standardised values for internal temperatures, solar and internal gains, hot water, lighting and appliance use. It provides a robust basis for assessing the energy efficiency of dwellings and the benefits which can be derived from energy efficiency measures.

Energy rating for dwellings An energy rating for a dwelling provides a single expression of its energy efficiency. The rating gives households a means of comparing one dwelling with another, or comparing the same dwelling before and after refurbishment. In particular, the use of energy ratings should enable households to take energy efficiency into account when buying or renting. For architects, ratings can be used as a design tool for optimising energy efficiency.

Two home energy rating schemes were launched in 1990: the National Home Energy Rating (NHER) and Starpoint. Both schemes rely on a computer program to calculate the annual energy requirements of the dwelling from a description of its construction and its heating system. Both also base their respective scales for energy efficiency on estimated annual energy costs, assuming a standard pattern of heating and occupancy. The Government has developed a Standard Assessment Procedure (SAP) for calculating energy ratings to allow comparison between the two methods. Both schemes have agreed to incorporate SAP in their calculations.



Good practice in the design of new housing The Building Regulations set minimum standards of insulation and ventilation for all new housing. There are many reasons why higher energy efficient standards may be appropriate:

Fuel costs are higher in some locations.

0 Above-average temperatures, or longer-than-average heating periods

0 Lower running costs may be required to make heating affordable to low

0 An environmental approach to housing or the adoption of a ‘green

may be required; for example, in old peoples’ dwellings.

income groups.

policy’ may require minimisation of energy use and consequent CO2 production.

In addition, future trends in fuel prices and in the practice of using dwellings for longer periods (as a result of an ageing population) and of working from home, will make energy conservation measures more cost effective over the years.

In most cases, an analysis of energy use can identify cost-effective opportunities to achieve higher energy efficiency. This is best done by using a computer program or worksheet based on BREDEM (see pages 110-1 11).

Method of assessment BREDEM is used to calculate the energy consumption of the proposed design35. Assessors will have the choice of using the National Homes Energy Rating (“ER) procedure or the MVM Starpoint procedure.

If the program shows an interstitial condensation warning, the designer’s attention in the provisional report will be drawn to which building element is responsible.

The final energy consumption figures are converted to COz production in kg/m2 per year, using the fuel multiplication factors given in the BREEAM Report3 and credits awarded according to the scale shown above. The U-values of all elements must meet or exceed the element requirements in the Building Regulations, but without the trade-off option between building elements.


J

- - ~. . -~ -_

Good practice in the design of new housing

BREEAM criteria are used to reduce the amounts of carbon dioxide released into the atmosphere, and thereby to reduce the contribution which the dwelling will make to global warming. The BREEAM criteria give credit, on a 6-point scale, to dwellings which are responsible for the production of less CO2 per square metre of floor area than would necessarily be achieved by complying with the Building Regulations.

0 1 credit for CO2 production of 105-91 kg/m2 per year Example: a house built to Building Regulations insulation requirements, with space heating supplied by a modem well controlled gas boiler

0 2 credits for CO2 production of 90-71 kg/m2 per year Examples: a super-insulated house with all energy supplied by electricity; a house b d t to Building Regulations insulation requirements, with space and water heahg supplied by a modem gas boiler

0 3 credits for CO2 production of 70-56 kg/m2 per year Examples: a house built to Building Regulations insulation requirements, with space and water heating supplied by a modem gas boiler, and all cooking by gas; a super-insulated house with space heating supplied by a gas condensing boiler

0 4 credits for CO2 production of 5546 kg/m2 per year Example: a house built to Building Regulations insulation requirements but with wihdows double glazed with low-emissivity glass and doors and loft' with additional insulation, space.and water heating supplied by a gas condensing boiler and all cooking by gas

0 5 credits for CO2 production of~45-36 kg/m2 per year Example: a super-insulated house with space and water heating supplied by a gas condensing boiler and all cooking by gas

0 6 credits for CO2 production less than 36 kg/m2 per year Example: a super-insulated house with heahg by a gas condensing boiler, a high-efficiency heat exchanger (heat recovery coil) for hot: water . . heating and a low-temperature heat distribution system

.


Chapter 11

Thermal insulation

Thermal insulation

Introduction Thermal insulation The quantity of heat needed to maintain comfortable temperatures in a house depends on how well it is insulated. A poorly insulated house needs a great deal of heat to keep it warm and it cools down quickly when the heating is turned off. It is likely to suffer from condensation on the inner surfaces of its exterior walls, even when it is well heated, which could cause damage to decorations and encourage mould growth.

Installing thermal insulation is often relatively easy when the house is being built but becomes very difficult or uneconomical at a later stage, unless it involves the straightforward task of filling empty wall cavities, or laying quilts in accessible roof voids. The design and construction of the house is therefore very likely to constrain its level of thermal insulation for the lifetime of the house. This is especially so for floor and wall insulation. Design decisions about thermal insulation can therefore have long term consequences, perhaps anticipating a time when energy supplies could be considerably more costly than at present.

Thermal insulation is recognised as an important factor in house design in the Building Regulations (and their counterparts in Scotland and Northern Ireland) which make provisions to ensure that adequate standards of thermal insulation are met. Since the levels of thermal insulation set out in the Building Regulations are only minimum requirements, insulation standards above the minimum are recommended in new housing. Any extra costs are likely to be small in comparison with the overall cost of the dwelling, and may be offset by the smaller and simpler heating systems, which are able to supply the reduced heating demand adequately.

General guidelines Applying a given thickness of insulation to a previously uninsulated element will have much greater effect than applying the same thickness where there is good insulation already. The main aim is to reduce the amount of heat lost from the house as a whole, so there is little point in applying very high levels of insulation to some elements while ignoring others. It is usually most cost-effective to ensure that all elements (floors, walls roofs and windows, doors and their frames) have good insulation rather than very high standards of insulation on a few elements, and low standards on others.

0 Insulation which is not continuous at corners and edges can cause cold bridges, which are small areas less well insulated than those which surround them. These can cause localised condensation and consequent mould growth, although they contribute little to the overall heat loss of the house. Care is needed to avoid cold bridges around windows, doors, edges of ceilings and floors, and structural elements and service ducts in flats.

BRE housing design handbook IPREVIOUS PAGE IS BlANKl 117

Thermal insulation

U-values recommended by the Building Regulations Approved Documents (W/m2 "C)

Roof Walls Floors

1965 1.42 1.70 1.42* 1976 0.60 1.00 1.00* 1982 0.35 0.60 0.60* 1990 0.25 0.45 0.45t

* Applies to exposed floors only. t Applies to all floors including those in

contact with the ground.

118

Fitting insulation generally causes temperatures on the warm side of the insulation to increase but those on the cold side to decrease. Condensation can result when moisture-laden air from within the house reaches those cold areas behind the insulation. Condensation can cause problems in some constructions (eg some designs of timber frame) so vapour control layers must be fitted where required. The effectiveness of vapour control layers must not be compromised by holes for access of services.

Some insulation materials (particularly polyurethane foams) have traditionally used ozone-layer-damaging CFCs or HCFCs in their manufacture. These should be excluded from dwellings and alternative products, which are available for most situations, should be used.

The BRE Publication, Thermal insulation; avoiding risks37, and the more recent NHBC/BRE /BRECSU/EEO publication Thermal insulation and ventilation38 advise on how to avoid cold bridges, condensation, frozen pipes and other hazards and offer practical guidance on the installation of thermal insulation.

The Building Regulations Building Regulations have always had provisions for thermal insulation. Provisions were also included in the model bye-laws which pre-dated the Regulations and have influenced the insulation of most dwellings built since 1945.

The 1965 Regulations for thermal insulation could be met by a standard brick-brick or brick-block cavity wall and 20 mm of glass-fibre quilt in the roof. The international oil crisis of the early 1970s led to growing concern about energy conservation. Regulations were formally revised in 1976 to deal with condensation, but included the specification of better U-values and a provision for limiting the total area of windows. Significant increases in insulation were introduced in 1982 and 1990. The 1990 revision introduced the concept of ground floor insulation for the first time in the UK. It also proved more flexible than previous Regulations by allowing builders to compensate for reduced insulation in one element by increasing it in another. Although many builders use other methods to meet the Building Regulations required standards, the floor should be insulated in highly insulated dwellings. The Table shows the U-values required by successive revisions of the Regulations.

Construction methods have evolved with the Regulations. The 1976 revision could be met by adopting lightweight concrete blocks for the inner leaves of cavity walls. The 1982 revision increased the use of insulation within the cavity itself but also led to the development of high- performance insulating blocks which allowed the cavity to be kept clear. Ground-floor insulation has not been widely used to date, and the most economical solutions will evolve to meet the growing market for such insulation. The Approved Document for Part L of the Building Regulations gives a range of solutions which meet the requirements.


- . -

Roofs

Roofs Insulation for pitched roofs is usually placed at ceiling level. Care is most needed at the eaves to ensure that the insulation extends over the top of the wall but does not block ventilation paths from the eaves. Figure 79 shows typical eaves detail.

A total insulation thickness of 200 mm in two layers is recommended (U-value approximately 0.25 depending on k value) with the top layer across the joists. This method will not be possible where the roof space is boarded, since deeper ceiling joists are needed to support the boards.

Insulated lofts are cold. To prevent tanks and pipes freezing, they should be located inside the heated envelope of the dwelling (see Figure 80). To prevent moist air from the house causing condensation in the loft, ensure that the loft is well ventilated by outdoor air and sealed from the rooms below (Figure 81).

Insulation may also be placed at rafter level, most commonly for room-in- the-roof designs (Figure 82). A total insulation thickness of 200 mm is recommended. This may be incorporated by battening out the rafters and by using insulated laminated plasterboard. Insulation between the rafters is most easily fixed using paperbacked insulation nailed to the rafters.

Ceiling penetrations

Rigid insulation to roof hatch

Figure 81

Typical eaves detail

Baffle to prevent insulation blocking

continuous

Figure 79

Insulate

RlsW main roof spac within heated

Loft insulation

Heat rising from below prevents freezing

Typical detail of room-in-the-roof Inert board used to maintain clear

Cross battens to

depth for services

Services routed on inside of vapour control layer to

to avoid cold avoid puncturing bridge [

Wall and ceiling vapour control layers lapped

Figure 82 and sealed

BRE hoirsing design handbook 119

Thermal insulation

Cold deck Weatherproofing , Roof deck - - Ventilated void

Vapour control layer

\Ceiling

Figure 83

Warm deck (sandwich)

Weatherproofing

-Insulation

\Roof deck


Figure 84

Warm deck (inverted)

,7-Ballast

1 I Insulation

'\Weatherproofing

-Roof deck

Figure 85

Protective treatment to waterproof membrane air space

Minimum 50 mm

I I \ / . ' insulation I I

\ Vapour

V 17 I n H Space \ for Ventilation air I 11 services

Figure 86

120

Insulation for flat roofs may be placed above the roof deck (warm deck) or below the roof deck (cold-deck). See Figures 83 and 84. A total thickness of 200 mm of thermal insulation is recommended, but this may not be possible for upgrading existing construction.

Note: For a flat roof, warm-deck construction should be used since cold-deck construction is more prone to condensation problems.

For cold-deck flat roof construction, ventilation of the void above the insulation is important (see Figure 86).


- z=x<

Wall insulation

El Wall insulation

External

Many types of construction meet the levels of thermal insulation recommended by Building Regulations and Approved Documents. Insulation may be applied internally, externally or in the cavity between the leaves of a cavity wall. Insulating masonry, ie masonry having good insulation properties, may also be used, either alone or in conjunction with other forms of insulation.

Timber framed 'construction allows a large thickness of insulation, while maintaining a clear cavity.

Insulation thicknesses of up to 100 mm are recommended in both fully- filled cavity construction and timber framed construction. Combinations of partial fill, insulating blockwork and insulated dry lining may be used to provide similar levels of insulation.

Care is needed to ensure that cavity insulation does not allow rainwater to penetrate to the inner leaf of the wall.

Filled cavities provide adequate resistance to rain penetration if proper attention is paid to design and workmanship and if certain constructions are avoided in areas of the country with the highest exposure to wind- driven rain. Guidance is given in the BRE Report Thermal insulation: avoiding risks3' and British Standard BS 5628:Part 3. Cavity wall insulation, either as insulation batts built-in during construction, or blown into the cavity post-construction, should be installed in accordance with a relevant British Board of AgrCment Certificate, or, for foam, with British Standard BS 5618. NHBC restricts the exposure zones in which full cavity fill can be used (see NHBC Standards Chapter 6.1 External Masonry W a W ) .

Wall construction

Solid masonry

Cladding or render

Insulation position

Optional cladding or render

0 0 0 U

Unfilled cavity

0 0 0 0

0 0 n

Cavity insulation

0 0 0 0

Insulating masonry

Internal


Internal

Insulating masonry

Partial cavity fill

Full cavity fill

Between studs

Option of layer

brickwork or cladding

to timber

In the cavity

Sheet cladding

Composite construction

Figure 87

BRE housing design handbook 121 r -~

'91

I I

I m

e-

i i i i - i

Doors and windows

Doors and windows Large heat losses are common through window frames and glazing. All glazing should be in factory-sealed double glazed units, preferably with a gap of up to 12 mm between the panes to reduce the U value. Metal frames should include a thermal break, and all frames should be ‘high performance’ to avoid seal breakdown of the double glazed units. (Reference 37 gives advice on how to detail the edge seal to avoid deterioration).

Heat loss through glazing can be further reduced by using a low emissivity coated glazing unit.

Heat loss and condensation at cold bridges can be reduced by placing insulation across the heat flow paths.

Hardwood frames should be avoided unless the wood comes from a sustainable source. The specification of hardwoods from tropical rain forests has been a major factor in their destruction.

Risk of cold bridge

I Lintel

Avoiding action

Jamb Sill

Figure 93 Continue internal insulation to the frame (applies also to external insulation)

BRE housing design handbook 131 I PREVIOUS PAGE IS BLANK I

Thermal insulation

I

Figure 94 Overlap window frame and insulating blockwork

M U

Figure 95 Use box lintel with insulation and use insulating cavity closers

Figure 96 If frame placed forward. insulate soffit. reveal and under sill


.

Floors

Floors Alternative dpm position /

Solid floors can be insulated by a layer of rigid insulation, either above (see Figure 97) or below the slab. Moisture movement has to be resisted by a damp-proof layer (minimum 1200 gauge polyethylene or 3 mm bitumen). Reference 37 advises on the position of the damp-proof membrane. Edge-of-slab insulation is also useful. Figure 97

The minimum thickness of screed over compressible insulation is 65 mm. Screeds thinner than this often cause defects. The screed can be replaced by plywood if the insulation is placed above the slab (Figure 98).

Composite panel

Combined dpm and / moisture barrier

Beam and block floor constructions should be insulated above the slab. Figures 99 and 100 show dpm positions for ground-supported and suspended reinforced concrete slab floors.

Some proprietary systems are available in which the blocks themselves are of thermally i,nsulating material giving, overall, high levels of insulation.

Insulation thicknesses of 50 mm are recommended wherever possible.

~ Loose-laid panels Moisture barrier Thermal insulation

-\\\ dPm Concrete slab

Figure 99 Ground-supported concrete slab floor

t

'Concrete slab

Loose-laid panels Moisture barrier Thermal insulation

I r \ I

' Concrete slab

/.::: battens

\y :?re barrier

Figure 98 Concrete slab

Reinforced concrete slab ,/ ,dpm above slab

\ r- \ 1 I \ ' More suited to reinforced Mesh concrete suspended slabs Figure 100 Suspended reinforced concrete

slab floor


- _ _ .-

Thermal insulation

Substantial thicknesses (eg 100 mm) of insulation can be easily provided under suspended floors (see Figure 101). Cold bridging should be minimised by making the insulation continuous, especially where joists run parallel to and adjacent with external walls (Figure 104).

Avoid using a damp-proof membrane or vapour control layer on suspended timber floors, since it might prevent spilt water from running away.

Insulation quilt

Figure 101 Ventilated void

,Quilt insulation

Nail fixina

Support batten Fw 102 Fibreboard support

Insulation cover continuous

1

I I

F w 103

Figure 104


Chapter 12

Space and water heating


Principles of heating Dwellings in the UK normally have some source of room heating to complement heating produced by cooking, gas and electrical appliances, occupants’ body heat and radiant energy from the sun entering the house through windows. The heating system must be able to warm the house to acceptable temperatures even in the coldest weather. It must also be controllable.

Adequate heating, ventilation and thermal insulation also help prevent condensation, by removing moisture and keeping surfaces warm.

Control should limit maximum temperatures of hot water for washing and cleaning to avoid scalding and reduce energy waste. Flow rates from different water heating systems vary, and should be chosen to be appropriate to the use.

Greenhouse gases As well as avoiding energy waste, the designer will need to consider how to select heating appliances which release the minimum of carbon dioxide into the atmosphere, thus helping to reduce global warming. Comprehensive British and EN standards will eventually be produced to make this task easier.

System choice Fuels The main fuels and methods used for heating are:

0 Naturalgas

0 Low and normal tariff electricity

Oil

0 Coal

0 Liquid petroleum gas (LPG)

Consider the following factors when choosing the heating method for a particular system:

Fuel availability Most fuels are generally available but natural gas is not available in some parts of the country, such as rural areas away from well populated centres.

Convenience Fuels delivered by cable or pipe, such as electricity and natural gas, are generally the most convenient for the user, although regular deliveries of other fuels are available. Coal is not suitable for some groups of people,

137 _- BRE housing design handbook I I 1 PRNOUS PAGE IS B M K I

- -


Factors to convert fuel prices to flGJ

Unit Conversion Fuel of price factor

particularly disabled and very elderly people, since it is less easily controlled than most other fuels and ash needs to be removed regularly from the appliance.

Electricity plkWh 2.78 Gas pltherm 0.096 Solid fuel Utonne 0.033 Oil, paraffin pllitre 0.27

LPG (propane) pllitre 0.39 LPG (butane) Pkg 0.20

Running costs Running costs between systems can vary depending on:

0 Fuelcost

0 System efficiency

0 Accuracy of sizing the system

Housesize

Hours of heating

0 The control system

Make comparisons using the BREDEM calculation method given in Chapter 10 or by referring to the dwelling’s Energy Rating. Standing charges (if applicable) and system maintenance costs should also be considered with fuel costs when calculating running costs.

It is difficult to give general guidance on running costs due to variations in fuel prices over time. The cheapest fuel will usually be natural gas, although off-peak electricity will be very competitively priced for small dwellings. Solid fuel prices vary and can give similar running costs to alternatives. Peak-rate electricity and LPG, which are never likely to give the lowest running costs, may be chosen for other reasons.

Oil costs will probably remain vulnerable to changes in availability and supply caused by political events and international price agreements.

Large fuel storage containers will allow LPG, oil and solid fuel to be bought in large quantities at lower cost, thus reducing overall running costs.

Capital cost of equipment

0 Type

System costs vary with:

0 Size (central systems become cheaper than individual room heating

Efficiencies (condensing gas boilers cost more to buy but less to run)

with size increase)

The cost of fuel storage facilities for coal, oil and LPG should be added into system costs.

Space requirements The amount of space needed for a heating system will depend on the type of fuel it uses. Space is needed outside for storing coal, oil and LPG and inside for heaters or boilers, heat emitters and domestic hot water storage. Space problems in small dwellings can be solved by using an appropriately compact type of heater or boiler, such as wall-hung boilers, back boilers, instantaneous water heaters, mains pressurised heating and unvented hot water systems.


System choice

Environmental factors Minimising fuel use by efficient house and heating system design is important for reducing pollution. However, the emission of carbon dioxide (the main gas contributing to the ‘greenhouse effect’) varies greatly between different fuels. The table shows the emission of CO2 per kilowatt of delivered fuel by type.

Carbon dioxide emission

Fuel kg/kWh delivered

Natural gas 0.198 Electricity 0.832* Coal 0.331 Oil 0.302 LPG 0.234

*Based on the overall mix of fuels used to generate electricity in the UK.



Warm air central heating

Gas burner

Electric storage I

Common heating systems

Ventilation

Heat recovery

Balanced flue boiler /

Balanced flue boiler

Cookers with boiler

Unvented domestic

systems

Other heating I Water storage systems - gas District heating

Block heating

Large scale combined heat and power

systems Communal heating

Micro combined heat and Dower

Underfloor heating

Heat pumps

Active solar heating

Figure 105



Common heating systems Full house heating can be supplied from a central heat source (usually a boiler, sometimes a heat store) and distributed by a radiator or blown air system, or it can be supplied by individual room heaters.'

Hot water is supplied from the central source or from an individual heating source, such as an electric immersion heater in a cylinder.

Wet central heating systems Open vented system The traditional central heating system used an open vented pressurisation system. Figure 106 is not in accordance with present practices.

Both the central heating and domestic hot water circuits should be pumped and separately controlled via thermostats and water valves. The boiler can be gas, oil, coal or LPG-fired or can be an electric heat storage system.

Open vent pipe Open vent pipe

L

Figure 106

Feed and expansion tank

Diverter valve - Isolating valve - Pump

Isolating valve - r ir

To draw-off taps

/-

-- =+l

i Cold storage tank I1 1 1 1

First-floor radiator

-L l p t h e r radiators -

I I II I1

I1 First floor

I 11 Ground-floor radiator {

To other radiators Boiler Ground floor - -

BRE housing design handbook 141 --


142

Automatic air release valve

Filling point

Sealed systems The advantage of mains pressurised (sealed) systems is that they can be used where there is no space for a feed and expansion tank or where there is insufficient headroom to provide the necessary pressure.

Sealed central heating systems As an alternative to an open vented heating system (see previous section), a sealed system may be installed. This system requires:

A boiler which is approved for this purpose

Special safety controls

An expansion vessel which will accept the changing volume of water as the temperature alters

Air in the pipework is generally vented through automatic release valves. The heating circuit must not be permanently connected to the mains water supply. For filling or re-pressurisation purposes, a temporary hose with adequate backflow protection must be used.

n I I K I I cylinder r B

Pressure gauge

Expansion k vessel ( -L Safety

valve

Boiler

Drain 0 cock

Figure 107

Top-up bottle

Alternative /

Heating flow

Heating return


L- A

~- --


Unvented domestic hot water storage systems Mains pressurised domestic hot water (dhw) systems can be used for example where there is insufficient headroom to provide an adequate flow of hot water from a tank feed, for example in a flat, or where it is preferable not to have water storage tanks in a loft space.

The design and installation of unvented domestic hot water systems is covered in the Building Regulations Part G3 (Hot water storage)29.

The conventional feed and expansion tank can be replaced by connecting directly to the mains water supply and by providing an expansion vessel if not accommodated in the cold feed pipework.

The Approved Document recommends:

0 Using a temperature and pressure relief valve, and a non-self-resetting thermal cut-out in addition to the control thermostat

0 For a system with a boiler, connecting the non-self-resetting thermal cut-out to a motorised valve so that water from the boiler is diverted from the primary heating coil if the water temperature becomes excessive

supplied either factory-fitted to the cylinder or in a kit form supplied by the manufacturer

0 All safety devices to be factory-fitted and all functional controls to be

0 Arranging for a competent person to service the systems regularly

Installation of unvented storage systems by a competent person is a requirement.

reducing Expansion

(if required)

water supply Expansion

vessel a safe and visible place

Figure 108 Unvented system with primary coil

BRE housing design handbook 143 --- -


Hot water to all taps and shower

II I

Service main Fignre 109 Combi-boiler installation

Central heating with instantaneous domestic hot water Both the domestic hot water storage cylinder and associated cold water storage tank can be eliminated by using a ‘combi-boiler’, which incorporates central heating and domestic water heating direct from the mains via separate heating coils, so that the central heating coil is cut off automatically when domestic hot water is required. Combi-boilers will always give a supply of (nearly) mains pressure hot water, while storage cylinder systems can run cold when hot water demand is high. Combi- boilers are particularly well suited to smaller dwellings, where hot water demand is limited, since water flow rates are low in comparison with the supply from a storage tank.

Combi-boilers frequently use sealed space-heating systems, though models are available which use sealed or open vented circuits.

All instantaneous water heaters may suffer from pipe scaling in hard water areas as mains water passes directly over the heated surfaces in the heat exchanger. Water softeners or conditioners should be fitted if scaling is a problem in the area.

Central heating using the ‘HomeWarm’ system The HomeWarm system was designed as a low capital cost gas central heating system for small well-insulated new homes, and the modernisation or refurbishment of existing small houses or flats.

It is a simplified wet central heating and stored hot water system, with the following features:

The small boiler heats either hot water or central heating at any time, allowing the use of a smaller boiler than normal.

A manual or thermostatic ‘comfort controller’ diverts the boiler output to either domestic hot water (dhw) or space heating, although 10% always heats the dhw. a* Hot taps

No flow to radiators

3-port Radiators Primatic cylinder - diverter

K 8 valve

Hot water

I rl1 ::::rator Figure llOa HomeWarrn system diverted to cylinder



Radiators Primatic cylinder

Heating

Figure llOb HomeWarm system diverted to radiators

There is an open (ie non-closable) link from boiler to dhw cylinder, with the boiler thermostat set at 65°C.

0 A ‘primatic’ cylinder (where the feed is inside the cylinder) which replaces the separate feed and expansion tank on the space-heating circuit.

Some limitations on comfort may be felt when there is a simultaneous demand for heating and hot water production.

Boilers Gas boilers Balanced flue boilers and condensing boilem Two types of gas boilers are commonly used for new housing: balanced- flue boilers and condensing boilers.

Balanced-flue boilers Balanced-flue (room-sealed) boilers, which can be floor or wall-mounted, draw combustion air from outside the building, emitting the exhaust gases directly through the wall in a concentric duct with the combustion air.

Room-sealed boilers (natural draught and fan-assisted) do not bum room air and so do not cause draughts, giving a higher overall efficiency than the more traditional open or ‘conventional’ flue. Fan-assisted units are smaller and easier to site.

Note: Avoid siting balanced-flue terminals close to windows etc, where fumes could be drawn into the dwelling (see section on flues).

0 Condensing boilers Condensing boilers incorporate two heat exchangers. The first heat exchanger removes the heat from the hot gases in the same way as a conventional boiler. The gases then pass over a second heat exchanger which removes some of the lower temperature heat of these exhaust gases and latent heat. As a result the exhaust gases are cooled to a point at

00 n o / U 0 I I

Air inlet 0 0

Air inlet

n o 00 n o o n n o o u 00

Figure llla

Products of combustion expelled

Figure l l l b

@=-


-


which the water vapour in the gases may condense out to be fed into a drain or soak away.

Condensing boilers achieve efficiencies of nearly 90% - much higher than for other gas boilers - and thus give high overall annual efficiencies with high part load efficiencies; eg when used for hot water production only in summer. Floor-standing and wall-hung condensing boilers are available and all models have r-oom-sealed (balanced) fan-assisted flues. Evidence from a large programme of demonstration projects funded by the Energy Efficiency Office shows condensing boilers to be highly cost- effective.

The exhaust gases from a condensing boiler form a plume in cold weather, due to the lower exhaust temperature. Whilst this is also partly true of conventional boilers, the plume from condensing boilers may cause distress. Take care to locate the flue terminal where it will not spoil views.

Open jlued boilers and back boilers Two other types of gas boilers, open flued and back boilers, have traditionally been installed in houses but are infrequently used today, as balanced-flue boilers are more efficient and cheaper and easier to install.

Open flued boilers Open flued boilers can be floor or wall-mounted with the flue rising to roof height or above. They burn air from the room in which they are situated, which therefore needs a fixed ventilator to the outside. They should only be used if there is no suitable outside wall for a balanced-flue boiler since the burning of room air can-cause draughts and wastes warm air. Flues and chimneys are also expensive to build, or to adapt with flue liners.

A ducted supply of air for combustion can be provided from the outside, emerging close to the boiler. This reduces draughts and encourages outside air to be used directly for combustion.

Back boilers Back boilers installed in a fire place behind a gas fire can supply central heating. The boiler operates independently of the fire but uses the same flue or chimney. As with open flued boilers, warm air is used for combustion, with similar disadvantages.

Choosing between gas boilers Balanced-flue boilers should be used where possible since fixed vents from the room to the outside are not required; thus warmed air is not wasted and draughts not caused. Condensing boilers are the most efficient and will give significantly lower fuel bills. They are more expensive to buy and the condensate drain needs to be plumbed into a drainage system or soakaway. Flue terminal location must take into account the plume of water vapour. Condensing boilers provide greatest savings in larger dwellings and small enough models may not be available for small dwellings. Even when oversized, however, they are still more efficient than a conventional boiler.

It may be necessary to use conventionally flued boilers if no suitable location can be found for a balanced-flue boiler (see page 162). Back boilers (conventionally flued) may be used for similar reasons or because a gas fire is wanted in the living room.



The additional cost of providing or adapting a chimney or flue also favours using a balanced-flue boiler.

Liquid petroleum gas (LPG) boilers LPG boilers are natural gas boilers with different burner assemblies, which are needed due to the higher calorific values and different burning properties of LPG. A full range of boilers is available including open and balanced-flued and condensing boilers. Higher fuel cost will restrict use of LPG to areas without a natural gas supply.

The LPG is delivered by tanker and must be stored fairly close to the house. Three systems are available:

0 A communal tank system If an estate is to be served by LPG, this can be installed with ‘mains’ and a metering system serving each house.

0 A bulk storage tank This can be used for an individual house and located in the garden within reach of the delivery tanker.

0 A four cylinder package This is normally only used where siting or vehicle access is a problem. The cylinders are replaced in pairs when empty.

Location of LPG tanks is subject to some restrictions; they must be installed in the open air, away from buildings, property boundaries and sources of ignition (see Figure 112).

Figure 1U

BRE housing design handbook 147 _ -

/

- .. -


Motor Screw feed

Figure 113

Figure 114

Oil boilers (balanced-flued and open flued) All oil boilers are floor mounted and require an oil storage tank situated close by. Two grades of oil can be used: 28 second and 35 second; but 28 second (kerosene) is recommended for domestic use due to its cleaner burning. Boilers down to 12 kW output are available although this may be too large to be economical for small houses.

Balanced-flue boilers should be used wherever possible. A 2500 litre oil storage tank is recommended (for boilers up to 30 kW output) for economy of delivery.

Coal boilers Two types of solid fuel boilers are commonly used for new housing, open flued boilers and back boilers with room fires or heaters.

Open jlued boilers Floor-mounted open flued boilers are available in all sizes for location in kitchens, utility rooms, garages, etc. Natural and fanned-flue models are available and ‘batched’ gravity feed is normal.

Boilers are normally controlled by their own internal water thermostats which operate dampers or the fan. Minimum full load efficiencies are 65%, with typical efficiencies of above 70%.

Fuelling is normally needed no more than once a day, and maybe only once every two weeks when equipment is used just for hot water production in summer. Mechanical de-ashing is normal and the residue is removed as often as fuelling.

An ‘ash tidy’ should be provided for every appliance. This is simply a closed box into which the ash tray is placed immediately on removal from the boiler. The whole box can then be taken for emptying without ash being spilled or blown away. ‘Coal flow’ underfeed boilers can be used for larger installations. In these boilers coal from a separate hopper is fed automatically by a screw up to the centre of the grate, with ash falling off the edges of the grate. The ash can also be taken away by a screw system. The advantage of the system, apart from the absence of manual stoking, is that bituminous coal can be burnt smokelessly, allowing its use in smoke control areas. This can result in significant running cost savings as bituminous coal is far cheaper than smokeless solid fuel for use in smoke control zones.

Back boiler systems Boilers used in conjunction with open room fires and room heaters (closed behind glass) can supply domestic hot water and a variable number of radiators. All require a conventional flue and are manually ‘batch’ loaded with fuel. Underfloor air supply can be used instead of the more common use of room air for combustion, though adequate openings on at least two sides of the building are needed to counter possible wind suction effects.

Natural and fanned flue models are available, with fanned flue systems having the advantage of a quicker warm-up on demand and the possibility of using time clock control. Thermostatic control of dampers or fans is common practice. Throat restrictors should be fitted to all open fires which can be used when the fire is hot, to reduce the loss of room air up the chimney over the fire.


I

Common heating systems ~ ~~

Recommended coal store sizes

Type of fuel

Boiler output rating Capacity Dense Coke (kW) (tonne) (m2 floor area) (m2 floor area)

Up to 15 1 1 1.5 15-25 1.5 1.5 2.25 25-35 2 2 3 35-45 3 3 4.5

Closed room heaters have higher efficiencies (up to 75%) compared with open fires with back boilers, but even these have efficiencies of between 60% and 70% if high output boilers and throat restrictors are used. Solid fuel cookers which also supply hot water and central heating via radiators can also be used.

Fuel storage facilities of adequate size and location must be provided for all solid fuel heating. Storage capacity should be as large as possible to take advantage of bulk summer storage, with a minimum volume of 2.7 cubic metres for carbonised smokeless fuel and 1.27 cubic metres for other smokeless fuels and coal.

Recommended coal store sizes Location of the store should take into account:

0 Parking and turning of the delivery vehicle

0 The carrying route to the store

0 The route from the store to the boiler or fire

Electric storage boilers Two types of electric storage boilers are available:

0 Dry-core

0 Wet storage

Electric cabling to the house must be adequately sized for the heavy electric loading, and the floor supporting the boiler must be capable of taking the weight.

Dry-core boilers contain high thermal capacity bricks which store the heat, and water-filled piping to transfer the heat via a heat exchanger to the house. They are normally suitable for small one- or two-bedroom flats, being available to store 50 to 100 kWh of heat and designed to fit under a worktop in the kitchen. Larger models up to 250 kWh are available.

Both types can be used as the boiler in a wet central heating system with the usual controls, but domestic hot water is always provided by an independent system (usually a dual immersion, off-peak electric storage

and the heat is stored until there is a demand for heating. Peak rate top-up heating is normally included.

Auxiliary Demineralised Demineralised Heat water water refill water header tank exchanger

cylinder). Both types of boiler are heated overnight by off-peak electricity \

outlet 1 /-

Ra&ator water intlet

/ Water supply to core

Storage core of refactory bricks Solenoid valve 6

Wet storage boilers are suitable for houses with up to four or five bedrooms, the heat being stored by water which is heated by several


Figure 115

Boiling tubes

149 ~. ~.


immersion heater elements. Storage units are about two metres high, and up to one metre in diameter. They can be built into the house or located in a garage or outhouse.

A third central heating system is available for small, highly insulated flats in which the heat source is simply a direct acting (on-peak) electric element in the water flow. Running costs are likely to be high except with moderate use in a flat with very low heat-loss.

Warm air central heating Warm air heating systems comprise a heat generator (gas or electric), fans, a duct system and controls. Domestic hot water can be provided from the same heating unit via a storage cylinder.

Careful design of ductwork and room outlets.is needed to allow good distribution of warm air without noise or draughts. Ceiling, wall or floor room outlets can be used, depending on size, layout and conditions. A return path for air to the heater must also be provided (not from kitchens and bathrooms).

/ 'Feed and ex'pansion I I

air grilles .2+6

supply registers

Gas fire (room sealed . ... Primary flow and

return pipes air L

. . or open flue)

Return air from living room I I Ill& Warm air heater unit

\ \- Low side wall / /

150

Figure 116


/


Operational control is by varying the volume of air delivered at a constant temperature.

Heat recovery from exhaust air is easily incorporated into gas-fired warm air systems. The heat recovery unit can be installed in the roof space, with the fresh warm air being introduced into the return air system to the heater.

Warm air heat recovery is suitable for meeting the mechanical ventilation option in the Building Regulations.

A recent development is the flue heat recovery system in which the flue gases pass through a heat exchanger where they heat fresh air. As with warm air heat recovery, the fresh warm air is introduced into the return air system to the air heater which increases system efficiency substantially.

Note: Warm air heating systems must be provided with effective filters on both the recirculating air and on the fresh air intake. Unless these are regularly cleaned or replaced, the circulation of dust and other matter around the house may exacerbate any sinus or respiratory problems of the occupants.

Ridge t e r m i n a m

\ Ventilation air constant volume drawn from \ rnof mace or outside

relief air grilles in bedroom doors I I

Q Primary flow and return pipes

Return2ir mixed with ventilation air

Flue terminating at ridge terminal

Gas fire (room sealed A k \.-- ~

b or open flue)

A Combustion/ ventilating air grille

Rectangular main di ia

Figure 117



Foul air to A

Figure 118

Room heaters with separate domestic hot water Individual heaters in each room of the house can supply ‘whole house heating’ adequately and can be cheaper to install than a central heating system.

Two systems are in common use: electric storage heaters and gas room heaters.

Electric off-peak storage heater systems Storage heaters use off-peak, night-time electricity to heat up bricks which store the heat until it is required.

A mixture of off-peak storage heaters and small on-peak heaters can be used to provide whole house heating.

0 In living and dining rooms, large bedrooms and (sometimes) halls use

0 In small bedrooms and bathrooms use small storage heaters (0.6 kW

combined storage and direct acting (on-peak) heaters.

rated) or peak-rate convectors.



0 In bathrooms use down-flow fan heaters and heated towel rails.

0 In kitchens use down-flow fan heaters or (slightly more expensive) plinth fan heaters.

Storage heaters should always have:

0 Internal charge controls which regulate the intake of electricity, based

Thermostatically-controlled dampers to regulate the outflow of heat as

on the core temperature and the setting

required

Peak-rate heaters should have thermostatic control.

The larger storage heaters can be fan-assisted to allow better control of heat use, although they are only recommended in particular instances, such as in very large rooms, or where there is a high ceiling or gallery. Misuse of fan-assisted systems can provide poor performance if heat is ‘wasted’ early in the day.

Thermal storage systems, whether of gas or electricity, have a number of advantages where the domestic hot water is mains fed. When the radiators demand heat, water at mains pressure is fed through the thermal store via a heat exchanger. Thermal stores are suitable for all types of dwellings.

Typically, domestic hot water is separately provided by a 210 litre electric dual-immersion cylinder, insulated with at least 50 mm of insulation, although sometimes smaller capacity cylinders are used.

0 The lower immersion element runs on off-peak electricity, providing a full tank of hot water for later use.

The upper immersion element runs on peak rate electricity and is used to boost the water temperature, if required, by manual or automatic control.

Cylinders can be vented or unvented. However, an unvented system can be mains-fed or cistern-fed, sometimes with a booster pump.

In typical use, off-peak electricity provides 90% of the annual heating fuel use, with on-peak electricity providing 10%.

Onloff switch P Room

water

mixing valve

Figure U1

t and ut control

Figure 119

I Heating elements

t

Li

Typical radiator sizes

Rating(kW): 15 2.5 35 Weight (kg): 80 110 150

150 150 150 550 800 1050

c (mm) 750 750 750

A (mm) B (mm)

Figure l2Q

Hot water f- I outlet

Upper element 4; ~

I Thermostats

Cold I element Lower 1 I ;::%itches

Night only


Figure U2

_ _ _ -. .


Heated convected Hot aases in room air out -

heat O m

R

CoolY 0 A\ 1" room air in 0

Gas burner

Figure 123 Gas fire

Heated convected

G i s burner Cool room air in

Figure U4 Wall heater

Waste outlet

Figure 125 Condensing gas fire

Gas room heaters with separate domestic hot water A mixture of gas-fired wall heaters, fires and water heaters is available to provide full house heating. A full system normally consists of

A gas fire in the living room

0 Wall heaters in the dining room, bedrooms, hall, bathroom and (large)

0 An instantaneous or storage domestic hot water system

kitchen

Gas needs to be supplied to all appliances. This is best provided by a whole house copper microbore piping system (eg British Gas-approved Micropoint carcassing system). Appliances are simply plugged into outlet sockets.

Gas fires come in a range of styles but all provide radiant and convective heating. Flames are visible in all, either plain or with simulation burning logs or coal which is open to the room or closed behind glass. Flames closed behind glass give much greater heating efficiencies than open fires: up to 75% compared with around 30%. Balanced and open-flued fires are available. Control is usually manual.

Wall heaters operate only as convectors and are usually balanced-flue type, being located on or near an external wall. Most are manually controlled without time clock or thermostatic control. Models with time clock or thermostatic control are available and these are preferable for best comfort levels with fuel economy.

Condensing gas fires, with efficiencies approaching 90%, expel the products of combustion and the condensate via a 28 mm diameter plastics flue-pipe which can be up to 4 metres long with up to four bends. This gives great flexibility for the location of the heating appliance.

A conventional storage system can provide domestic hot water via a small gas 'circulator' usually with a balanced-flue. Alternatively, instantaneous multi-point water heaters provide hot water without storage and are connected directly to the water mains. balanced-flues are common, but fanned flue versions are available that allow up to three metres of horizontal flue.

Note: In hard-water areas water sopeners or conditioners should befitted to instantaneous water heaters. All water heaters would benejit in hard-water areas.

A system has been developed to reduce the number of room heaters and thus the capital cost in a house while maintaining full comfort temperatures. The system comprises:

0 Two large room heaters, one in the living room and the other in the hall

High-level ducts between kitchen and living room to effect heat transfer

Vents above the door-opening and at the bottoms of doors in upstairs

0 Extractor fans in kitchen and bathroom to help move warm air into

0 An instantaneous gas water heater

rooms to allow warm air from the hall to pass into the rooms

these rooms


Other heating systems

The success of the system depends on house layout since it is only appropriate for two-storey, well insulated houses. Good comfort conditions and high user-satisfaction have been demonstrated. Check for compliance with local fire regulations.

Other heating systems The common heating systems described in the. previous section are most appropriate for the vast majority of new houses and flats, although other heating systems can be appropriate in some circumstances.

Communal heating Where dwellings are grouped together, one heating source can provide space heating and hot water heating to several dwellings. This can be appropriate for sheltered, hostel or other special types of accommodation. It is essential to insulate main distribution pipes, or systems will prove very inefficient.

Block heating is the term used for a number of dwellings in one building heated from a central boiler room.

District heating Groups of houses may be heated by ‘district heating schemes’, which provide circulating hot water from a central boiler. Houses and flats should be individually controlled with a time clock and thermostats, and consumption measured with a heat meter.

Individual metering An individual metering system called DataGas meters each flat on the basis of the flow of hot water used. The system uses a water thermal heat store in each flat with a thermostat controlling the through-flow of hot water from the distribution mains. Consumption is based on a remotely- read simple flow-meter, as the distribution mains water is kept at constant temperature, the heat store providing the space and water heating as required in the flat.

Combined heat and power schemes (CHP) CHP refers to the use for heating of the cooling water from power stations. The hot water is carried in mains and distributed to local commercial, industrial and domestic premises, to provide space and process-heating. No large-scale CHP schemes exist in Britain, but their adoption could provide lower cost heat with a great increase in the overall efficiency in operation of power stations.

Micro CHP Small-scale CHP systems consist of gas-fired internal combustion engines driving electric generators with the cooling water used as the heating for the building. The electricity is either consumed on the premises or sold to the National Grid.

Underfloor heating Underfloor heating using off-peak electricity should only be used in special circumstances; eg in sheltered housing or old people’s dwellings



156

where long periods of even temperature distribution are required. It is not easy to repair.

Underfloor heating can also be provided by a wet system connected to a condensing gas (or oil) boiler. In specific situations, such as old people’s dwellings, the high capital cost of the system can be repaid by the low running costs since it produces efficiencies above 90% all year round.

Note: Due to the slow warm-up rate of underfloor heating systems, a n additional system for rapid warm-up may be needed.

Ceiling heating Ceiling heating is not recommended.

Heat pumps Heat pumps may be used for domestic heating purposes. They work by transferring heat obtained by refrigeration of external air or water sources, to the air or water used for heating the building. Electricity is the usual motive power, though gas-fired heat pumps are under development. They can be used to ‘upgrade’ reclaimed heat (from a ventilation system for example) and may be run on off-peak electricity together with a heat storage system. Heat pumps are generally unlikely to provide the most economic solutions at present.

Active solar space and water heating Active solar space-heating systems can provide between 20% and 40% of the annual costs for space and water heating. Solar heating can only supplement a full heating system, however. so the capital cost of the system is unlikely to make it cost effective under most conditions.

Since hot water is needed all year round, solar hot water heating (dhw) is more common than solar space-heating and can have a simple payback time of between 5 and 8 years. In an energy efficient house where the hot water requirement is 20-50% of the total heating demand, installing solar water-heating may prove more cost effective than further space-heating conservation measures.

n..

Two collector types are commonly used:

Flat plate This is usually single glazed with copper waterways and high absorption surface coating. The use of ‘transparent insulation’ in future may improve performance significantly.

0 Evacuated tubular This is more expensive but more efficient at low ambient temperatures. It usually comprises a ‘heat pipe’ system inside an evacuated tube, feeding to a water manifold.

The hot water storage tanks can be separate or integral, with integral tanks being cheaper and simpler to install but creating a problem with appearance.

Note: Luke-warm solar heated water should not be used directly, but only as pre-heat; ie, as supply to further heating.


L 2

Heating system design

System details Collector-able to withstand high temperatures (1 20°-200° C)

, - - - Thermostatically controlled j Or pam;aneous hotwater Non toxic antifreeze circuit (or automatic drain down , system) Face south f 45O n

Non-return valve capacity 30-50 litres

per m2 of collector area

Figure U6

Water heat storage systems Gas-fired water heat storage systems may be used in small well insulated dwellings. They use a small boiler, or circulator, to maintain a reservoir of hot water which is pumped round the radiator circuit to provide space- heating when needed. Domestic hot water is supplied by mains pressure water passing through a heat exchanger in the storage tank.

Advantages are: - Mains pressure hot water (useful for showers) - Rapid space-heating warm up - Boiler, storage cylinder and feed and expansion tank installed as a

package

Capital costs for these systems are similar to those for a conventional system. Running costs vary with use, storage tank insulation and boiler controls. A well designed system in full use will give running costs similar to conventional systems, but can produce low efficiencies if it is used only to heat water in the summer.

Heating system design Heating systems must be designed to warm the house in a reasonably quickly from cold to the required design temperatures (see Table overleaf). However, systems which are oversized will tend to be inefficient in operation.

System design - central heating source 0 For natural gas, LPG and oil-fired systems use British Gas Design

Guide Central Heating: a guide to the design and operation of domestic wet central heating systems''''.

Economy 7 Boilef'l for central water storage boilers and the Installers Guide42 for central dry-core storage boilers.

appliances approved by the 'Domestic Solid Fuel Appliances Scheme'.

For electric systems use the Electricity Council Guide DOM 10, The

0 For coal systems use similar design criteria as for gas and choose

BRE housing design handbook 157 r -

__ ___


0 For gas-fired warm air systems, use the British Gas Systems Design Manual.

These additional guidelines should be used:

Calculate the individual room heat loss rates at the design conditions (see table below). These calculations must take into account the heat losses or gains between adjoining rooms. Make an additional allowance for heating-up, calculated per unit floor area (see table below).

Determine radiator sizes for wet systems by choosing the smallest radiator which has an output larger than the total room heating requirement. In well-insulated houses it may be possible to replace two very small radiators in adjacent rooms with one larger single radiator located near both rooms.

The boiler size should be the total of the calculated radiator outputs plus an allowance for hot water, if the water is supplied from the same system. The boiler selected should be the smallest boiler available exceeding this total. No other allowances are recommended. (Not applicable to electric storage boilers.)

Temperature Design air change Recommended design conditions ('0 rate (adhour)t

Living areas, lounge, dining, study, bedsit, etc Kitchen Bedrooms (not used as dual purpose,

eg bedsit or study) Circulation areas, landing Toilets Bathroom Adjoining houses (design assumption) External: S England, Wales, N Ireland

N England, Scotland

21 1.0-2.0 18* 2.0

18* 0.5-2.0 18* 1.5-2.0 18* 2.0 22 2.0 11 -1 -3

(NHBC requires -1' external condition throughout UK.)

* For housing for elderly people, 21'C is recommended throughout.

t In dwellings carefully constructed to minimise air infiltration with full draught stripping, the lower air change rates can be used. The higher rates should be used on traditional 'leaky' housing. Use these air change rates only to calculate the maximum size of heating equipment. Use average air infiltration rates for energy consumption calculations.

Heating up allowance for intermittent use: 10 W/m2 floor area. Addition for hot water: if boiler also provides hot water, add 2 kW.

System design - individual room heating For electric systems, use the Electricity Council publication: The design of mixed storage heater/direct systemf13.

For gas appliances, design room heat loss according to note 1 above for central heating, and choose the smallest room heater with an output larger than the calculated room heating requirement.


Hot water system design

Hot water system design Domestic hot water can be supplied from the mains or from a storage tank. Instantaneous systems are usually gas-fired from specially designed boilers (see pages 148-149). Hot water storage systems can be heated by any fuel.

For the design of natural gas, LPG and oil-fired systems, use the British Gas Design Guide Central Heating: A guide to the design of domestic wet central heating systemflO. See also pages 148-149.

For the design of electric systems use the Electricity Council publication, DOM 9, Design of Economy 7 water heating"? (see also page 153).

For domestic hot water cylinders (not Economy 7), in two or three- bedroom properties, a tank of 210 litres (nominal) capacity is generally sufficient. In larger properties, with separate en-suite showers or bathrooms, install cylinders with a higher capacity.

All hot water storage cylinders should:

Where appropriate, have a high recovery heating coil which requires less time to heat up and reduces boiler cycling with commensurately lower hot water running costs

0 Be as near to the bathroom and kitchen as possible to minimise the length of pipework to domestic draw-off points

Have pumped circulation from the boiler to the cylinder, to improve recovery and reduce energy consumption

0 Be lagged with a 50 mm insulating jacket, or equivalent

Controls The provision of heating system controls is required by the Building Regulations. In England and Wales this is covered by Part L.

Controls are important in all housing to ensure that heat is provided when and where it is required, to avoid overheating and to maximise the benefits of conservation measures and solar and incidental gains.

The time switch turns on the heating system to heat up the house and hot water to the required temperatures by the time they are required. It then turns off the system when no more heating is required. The room and cylinder thermostats turn off the pump or fan and the heat source, when temperatures are sufficiently high and turn them on again when temperatures fall below the set temperatures. Better control of the temperature in individual rooms can be achieved with thermostatic valves on radiators.

Note: All controls for heating and hot water must be clearly labelled with their function, unless it is obvious from their design.

Time switches Electronic time controllers with separate provision for both space-heating and water heating times, and for each day of the week should be used.

159 - BRE housing design handbook -_


Choose a time switch that is easy to understand and programme and has default values included. For hot water heating, a time switch incorporating a one hour ‘boost’ facility should be specified.

Boiler control In a typical central heating system (with room and hot water thermostats), both boiler and pump must be switched off when the thermostats are satisfied. When fitted, pump over-run devices (to scavenge heat from the boiler or stop local boiling in lightweight boilers) should run the pump only during the scavenging period. For solid fuel boilers, with fan-assisted combustion, the fan should be switched off but otherwise the controls cannot switch off the boiler.

Room thermostat A room thermostat or thermostatic radiator valves are required by Building Regulations. In England and Wales this is covered by Part L.

A room thermostat should always,be fitted in the main living room, away from the doors and direct sunlight. Circuitry must turn off the boiler (as well as the pump) when there is no demand for heat, to prevent the boiler short cycling inefficiently (except in the case of solid fuel appliances).

Thermostatic radiator valves To maximise the use of solar and incidental gains, thermostatic radiator valves should be fitted in all rooms, with the exception of the one with the room thermostat. Valve heads should be fitted horizontal and not above hot pipes, where localised heating could affect the operation.

Zoning In larger houses, the heating circuit can be zoned into bedrooms and living rooms, and separate time controls fitted. Where there are separate upstairs and downstairs heating circuits, zone control of the upstairs temperature is advisable.

Electric mixed off-peak and on-peak Use storage heaters with integral room temperature charge controls and use off-peak heaters with integral thermostats and time clocks. External weather sensors, which adjust the charge taken by storage heaters depending on external temperatures, should only be used in particular situations; eg in groups of sheltered housing or large blocks of flats.

‘Cyclo-controlled’ systems are available for controlling input to storage heaters in groups or blocks of housing. Mains signalling is used, regulated by the electricity supplier, to switch on the supply to heaters as required by external temperatures and when most beneficial for the supplier in terms of load management. Billing is on a communal basis for all the off-peak electricity used, and a lower tariff may be available.

Central control units for electric heating systems are either ‘hard-wired’ or can be ‘mains’ signalled’. They can provide a comprehensive control strategy for peak and off-peak heating and hot water and can incorporate control of washing machines and dishwashers. They should only be used where special control is necessary.


Radiators

Cylinder thermostat and time clock A cylinder thermostat is recommended by the Building Regulation Approved Document L and a time clock control should also be provided for cylinders with a capacity of more than 150 litres (except those heated by off-peak electricity, where the thermostat is built into the heating element). The cylinder thermostat should be two thirds of the way down the cylinder.

Boiler energy management systems (BEMS) A range of more comprehensive electronic control systems, known as BEMS, are able to improve efficiencies in boiler, water circulation temperatures, start-up times, over-run times, etc. They are only recommended for larger houses, where a high level of control is required, or in sheltered housing.

Unvented hot water systems Building Regulation G3 contains requirements for unvented hot water systems with more than 15 litres storage capacity, to prevent the hot water storage temperature exceeding 100°C.

Radiators The positions of radiators in a room should depend on the layout of the room and possible positions of furniture. See Chapters 15 - 18.

In rooms withovt double glazing, radiators are best placed under windows to reduce cold air movements and the ‘cold radiator’ effect of the glass surface. If full length curtains are likely to be used, place radiators where they will not be covered by the curtains.

If radiators are placed under windows, provide window sills (or shelves) that extend over the radiator. This reduces direct loss to the windows and ensures that curtains insulate the windows from the hot convection air when curtains are drawn. Use shelves above radiators which are not placed below windows since this is useful for reducing staining on the wall and providing better heat distribution in the room.

Steel panel radiators are the most commonly used type of radiator. Fanned units should only be used if specially required; eg in ‘kick’ spaces in kitchens. ‘Cool’ cover radiators are useful where scorching could cause a problem as in nurseries or old people’s dwellings. Skirting heating (finned tube) radiators can be used under low windows.

Building Regulations Cylinder, pipe and duct insulation Insulation of hot water storage cylinders, pipes and ducts is required by the Building Regulations (Part L In England and Wales).

Insulation of pipes and cylinders is inexpensive and most important in reducing heat losses, both to reduce energy consumption and stop overheating of rooms in hot weather.

Hot water cylinders should have well-fitting insulation jackets of 50 mm minimum thickness. Two jackets can be used on top of each other if



162

necessary. Cylinders insulated with factory sprayed insulation are recommended as long as the insulation does not contain CFCs or HCFCs.

All pipework between boiler and storage cylinder, and all pipes one metre from the storage cylinder, should have insulation of thickness (minimum 13 mm) equivalent to the pipe diameter.

Insulate all pipework outside the insulated house envelope, eg in roofs and under floors, to reduce the risk of freezing. British Standard BS 6700 applies.

Use insulation which is manufactured without the use of ozone-damaging CFC or HCFC blowers. Alternatives with no damaging effects on the environment are available.

Insulate all ducts for warm air heating passing through unheated spaces.

Air supply to heaters Air supply to heaters is covered by the Building Regulations (Part J in England and Wales).

All gas, oil and coal heaters must have an adequate supply of air for combustion and working of the chimney or flue. balanced-flue heaters have no special requirements for ventilation of the room in which they are located as their combustion and flueing are sealed from the room (see page 163). If the boiler is located in a compartment, however, the compartment must be ventilated. It is preferable if this can be vented to inside because of the considerable loss of heat if it is vented to the outside. However, rooms containing traditionally flued heaters require permanent ventilation to external air either directly or, if to an adjacent room or space, this must also have the same sized opening direct to external air.

The minimum requirements are:

0 For gas heaters, 450 mm2 of permanent ventilation for each kW of appliance output rating exceeding 7 kW; some kinds of inset gas fires require permanent ventilation even if less than 7 kW capacity

For oil heaters, 550 mm2 of permanent ventilation for each kW of appliance output rating above 5 kW

0 For solid fuel heaters (other than those open to the room), 550 mm2 of permanent ventilation for each kW of appliance output above 5 kW. Where a flue draught stabiliser is used, the total free area should be increased by 300 mm2 for each kW of rated output

For solid-fuel open heaters, an air entry opening or openings with a total free area of a least 50% of the appliance throat opening area is required - as defined in BS 8303: 1986 Code of Practice for installation of domestic heating and cooking appliances burning solid mineral fuels

The fresh air supply should enter the room as near as possible to the heater to reduce draughts and to reduce the waste of warm room air. Underfloor ventilation with fresh air introduced adjacent to the heater (or under the hearth in the case of coal burners) can be worthwhile, but external entry points for the air must not be susceptible to wind direction that might produce negative pressure in the room. Underfloor ventilation is not acceptable in the case of some decorative effect gas heaters.


Building Regulations

Hearths to heaters Hearths to heaters are required by the Building Regulations (Part J in England and Wales).

All fuel burning heating appliances, other than wall-mounted types, require a non-combustible hearth beneath and around the heater to the dimensions laid down in the Building Regulations.

Boiler flues Correct design of flues for space and water heating appliances is of crucial importance for the safety of occupants as well as for the efficiency of the appliance. Flues to heaters are covered by Building Regulations (Part J in England and Wales).

Recommendations are summarised here for two types of flue:

Balanced

Conventional

Balanced flues for gas boilers (room-sealed systems) Balanced-flue appliances are produced with both natural draught and fan- assisted balanced flues. Those appliances with fan-assisted flues normally have smaller outlets than the natural draught versions. Some balanced flues can be fitted from inside the premises, thus avoiding the use of scaffolding for installations considerably above ground level. Some appliances have side flue outlets which can be used where there is insufficient room for the fixing of a rear outlet appliance.

Fan-flued appliances are available with flue extension kits which enable the appliance to be positioned up to 2 metres from the external wall of the building where the flue terminal is to be positioned.

The terminal must be positioned to allow the products of combustion to disperse freely at all times. Dimensions for positioning are shown on the table overleaf.

Under certain weather conditions a terminal may plume. Avoid terminal positions where this would cause a nuisance.

BRE housing design handbook 163 _ _


Balanced flue terminal positions

Minimum distance

Terminal position as illustrated Natural Fanned in Figure U7 draught draught

A

B

C

D

E

F

G

H

I

K

L

Directly below an openable window or other opening; eg air brick

Below gutters, soil pipes or drain pipes

Below eaves

Below balconies

Beside vertical drain pipe and soil pipes

Beside internal or external covers

Above ground or balcony level

From a surface facing a terminal

Where a terminal faces a terminal

300 mm

300 mm*

300 mm*

600 mm

75 mm

600 mm

300 mm**

600 mm

600 mm

Vertically from a tenninal on the same wall 1.5 m

Horizontally from a terminal on the same wall i 300mm

In a car port beside an opening (eg door, window) into dwelling (not illustrated) 1.2 m

300 mm

75 mm*

200 mm*

200 mm

75 mm

300 mm

300 mm**

600 mm

1.2 m

1.5 m

300 mm

1.2 m

*If the terminal is fitted within 850 mm of a plastics or painted gutter or 450 mm of painted eaves, an aluminium shield at least 750 mm long should be fitted to the underside of the gutter or painted surface.

**If a terminal is fitted less than 2 m above either a balcony or ground level, or a flat roof to which people have access, then a suitable terminal guard should be provided.

Vertical flued room sealed gas boilers'are available which draw combustion air from the loft and exhaust the waste gases through a roof mounted terminal.

All room sealed appliances are supplied with their own specifically designed terminals.

A guard over the terminal may be required if the terminal is less than 2 metres above ground level where people could come in contact with it, or the terminal could be damaged.


- _ _ . . .. . - - - .

Building Regulations

\ ---f

Figure U7

Flues for conventionally flued heaters Conventionally flued heaters must discharge to the external air via a flue pipe or chimney. Flue pipes must be sized to that of the flue outlet of the appliance or as given in the Building Regulations.

Flues must be constructed of appropriate durable materials and be insulated from combustible materials in the building. a Ridge

height 'h'

.- . -- - -_ 600 mm minimum

obstruction within

minimum

\or under Parapet or other obstruction \

I

\

minimum

than 4

Less than

Pitched roofs I

250 mm

obstructions

parapets

Adjacent construction within 1.5 m

Figure 128

Flat roofs


Chapter 13


PREVIOUS PAGE IS BLANK


Ventilation requirements All rooms in houses need ventilation to remove excess water vapour, carbon dioxide and smells, as well as other pollutants such as smoke, radon and volatile organic compounds from the use of solvents. Ventilation also provides fresh air for breathing and for combustion in fires and cookers. Older houses tend to have many ventilation paths. New housing is frequently constructed with very reduced paths which allow uncontrolled air movement between the dwelling and outside. This helps to keep the building warm and to reduce fuel consumption for heating.

Layout Where possible, draught lobbies should be included in dwelling layouts, especially where external doors open directly into living areas. Internal draught lobbies are best, but external lobbies, as long as they are unheated, are effective in reducing heat loss.

Air paths in the structure 0 Cracks in ceilings and walls should be sealed after the drying-out period. 0 Seal joints in ground floors between sheet materials. Ensure that all

joints are tongued and grooved wherever possible. The perimeters of floors should be sealed to adjoining walls.

0 Joists fixed on hangers will not allow air infiltration; built-in joists usually will.

0 Where services (pipes, drains, cables, ducts and electrical fittings) enter the dwelling, make a good seal around the entry point with foam, mastic or other flexible material.

0 Draught-strip loft hatches and use ‘pull tight’ catches. 0 Use an effective mastic seal on door and window frames at their

junction with the external wall. This can be either on the external face or the internal face, as appropriate to the design.

Fully filling wall cavities, preferably with post-construction blown insulation, will greatly reduce the movement of air through the cavity. The use of purpose-made cavity closers around door and window frames reduces air movement and alleviates a potential cold bridge.

Draught-stripping All door and window frames should have built-in draught-stripping of the compression tube, or wiping blade type, or alternatives which will perform to the same standard. Door threshold draught-stripping is important.

Testing The airtightness of a dwelling can be tested by pressurising the inside (sometimes called blower door testing) with a door mounted fan and by measuring the air flow. Air change rates under normal conditions are derived from the pressure data. These should give an air change rate per hour of between 0.5 and 1.0 for the whole house. To achieve these rates demands care on the part of the builder.

BRE housing design handbook I PREVIOUS PAGE IS BLANK I 169


Airtightness

~ To satisfy BREEAM criteria for airtightness, a dwelling should have:

0 Windows and doors fully fitted with draught seals.

Window and door frames sealed within the structure (eg with

0 EITHER wet plastering OR dry plasteringhing with continuous

silicone/mastic).

ribbons of adhesive around the edge of each board, including behind kitchen cupboard units, panelled baths and vanity units, and small cut pieces of plasterboard around window and door reveals.

Make good and seal all holes in the airtight structure which allow the entry or exit of gas, electrical and water services.

In a timber-framed structure, fit all walls and upstairs ceilings with a polyethylene vapour control layer (500 gauge) which is properly jointed (the vapour control layer should not use recycled polymer because this reduces its durability).

airtight structure, fit gas, electrical and water services with care to avoid puncturing the vapour control layer, or fit them within a space between the vapour control layer and the plasterboard lining.

If open-flued fuel-burning appliances are used in the dwelling it is essential that the air supply openings required by Building Regulations are provided. Where a very high level of airtightness is achieved in the dwelling structure it may be necessary to oversize the area of these air supply openings to ensure that the appliance operates correctly.

0 If a mechanical ventilation system is to be used, there should be either no chimneys/flues in habitable rooms or the chimneys/flues should be capable of being closed with a good level of airtightness when not in use, without creating a health or safety hazard.

0 With passive stack systems, the general airtightness should be complemented by trickle ventilators as specified in the Building Regulations Approved Documents F24.

In dwellings which rely on a vapour control layer to achieve an

These criteria may be waived if a particular combination of design and building procedure has been subjected to fan pressurisation testing by an authority acceptable to B E . Alternatively, a provisional credit,may be awarded if a commitment is made to such testing when construction is completed. The standard required will be 7 air changes per hour (ach) at a test pressure of 50 pascals for M V and 9 ach for PSV.


A irtigh tness

The indoor environment and health Many pollutants are found in the indoor environment; these include formaldehyde, wood preservatives, other volatile organic compounds, living organisms (eg bacteria, moulds, dust mites), particulates and fibres (eg man-made mineral fibres, asbestos), radon, combustion products (eg nitrogen dioxide), and lead. While there are now satisfactory procedures for dealing with many of these, others are increasingly causing concern.

The issues differ between homes and other buildings. For example, in some office buildings the occupants report a range of minor building- related symptoms (sick building syndrome). This is not commonly reported in homes but it is not clear whether this is due to differences in design (eg the presence or absence of air conditioning) or differences in response (eg individual householders improving their own environment, compared with groups of office workers taking complaints to a building manager). Similarly, Legionnaires’ disease and Pontiac fever, associated with wet cooling towers and domestic hot water systems in complex buildings, are not usually attributed to water services in homes.

In homes, many issues can be dealt with by good provision of ventilation and careful choice of materials and construction practice. There is also scope for improving physical aspects of the environment, and safety in the home, through simple changes in dwelling design.

The designer must either specify no use of coal tar products or obtain assurance from suppliers of any coal tar product (eg cold-applied bituminous damp-proof membrane) that quality control during manufacture will result in no noticeable naphthalene in the completed building. A letter from the manufacturer will be acceptable.

The design must show EITHER loft boarding OR all man-made mineral fibre (MMMF) loft insulation completely enclosed in polyethylene with no cut sections, OR the use of an alternative insulation material. Boarding must be at least 1.2 metres around loft hatch or hatches, 0.6 metre around any water tanks (or to the edge of the roof space) and 1.2 metres wide between any hatches and water tanks. For safety reasons the design must show a light in any boarded loft space, which can be switched on without entering the loft using a switch with an illuminated off/on indicator.

The builder must confirm that complete vacuum cleaning of all floor and worktop surfaces and inside all fitted cupboards and wardrobes will be carried out after all building work is complete and before occupation. Instructions to the sub-contractor must show this requirement.

The materials specification must show the absence of materials containing asbestos and paints containing lead.

EIRE housing design handbook 171 ~

~

-


BREEAM criteria require a reduction of the levels of volatile organic chemicals (VOCs) in the indoor air of new homes at the time of first occupation. .

In particular, credits are given for reducing levels of volatile organics by specifying:

Adherence to BREEAM guidance on ventilation prior to occupation

Urea formaldehyde foamed insulation (TJFFI) either not used, or used only in accordance with British Standards BS 8208, BS 5618 and BS5617. ,

Products which could emit naphthalene either not used, or used only ’with product quality control arkeditation.

The designer should specify that the builder must coniirm that the specified British Standards will be applied and that the specified ventilation practice will be followed.

After internal finishing (decoration of walls, ceiling or internal wood surfaces, floor coverings) has started and until the day before occupatio&

When work is in progress and someone is working inside the

- ,

dwelling, windows andor external doors are to be kept open andor extract fans left on (in at least two rooms on different faces of the

are to be left open at all times in all trickle vents are notpresent, background mechanical ventilation to operate at all times.

- - r 2 .

A statement must-be passed to sub-contractors to ebforce this procedhe: The prokduremust be followed where weather conditions permit: for example, where excessive ivind or rain would not hinder the‘ process of “decoration. From the point of +iew

eed to be used during this time, & volatile organic chemicals, but it -

reqeement. --


Airtightness

Volatile organic pollutants of indoor origin Several commonly occurring substances can be considered as indoor pollutants, although it is only their concentration that causes them to pollute the indoor environment. Other substances may be dangerous to health, even in moderate concentrations.

Carbon dioxide Carbon dioxide, which is produced by people and animals and by burning substances (eg cooking with gas), needs to be removed from the house to be replaced by oxygen. CO2 may also arise from landfill gasses, and from the ground in chalk areas.

Water vapour Water vapour is always present in the air in variable proportions. Various activities within the house produce additional water vapour, people, cooking, bathing and showering, clothes drying, etc. This can cause condensation on windows and other cold surfaces, and possibly mould growth and damage to materials.

Smoke Smoke is produced by tobacco smoking which is widely believed to be injurious to health.

Smells (other than smoke) Smells are produced by people and by food preparation and cooking. Although they are no hazard to health, they may be unpleasant and need to be diluted or removed.

Formaldehyde Formaldehyde is released from many building materials including chipboard, adhesives and urea formaldehyde foam cavity insulation. Formaldehyde vapour has imtant properties and may produce discomfort as a result of eye, nose and throat irritation. Exposure to high levels of formaldehyde, eg in the workplace, can lead to sensitisation. (Sensitisation means that a reaction could occur on subsequent exposure to the substance.) However, this is very unlikely to occur from the much lower levels found in buildings. With ventilation rates above half an air change per hour, concentrations of formaldehyde are not enough to cause problems.

Radon Radon is a natural radioactive gas with no taste, smell or colour. It is formed from the radioactive decay of uranium and is present in variable, small quantities in all soils and rocks. It can seep into houses through any opening between the house and the underlying soil or rock. The air pressure in the house is often slightly lower than that in the soil and so air is drawn from the ground into the house. Exposure to radon and its decay products over many years increases the risk of developing lung cancer.


~~ ~~ ~~

1


(a) Old houses Through holes around water and lighting fittings Around loft hatch Through cracks in ceilings and walls Through air bricks Into cavities via built-in joists Through suspended floors Up chimneys Leaks around doors Through opening windows Through cracks around window frames

(b) Newhouses (without specific ventilation measures)

Service ducts sealed Sealed loft hatch Well sealed structure Joist hangers used Solid floors No chimneys Doors draught-stripped Windows draught-stripped

Figure U% and U9b Reduced ‘natural’ ventilation can lead to problems of condensation, smells and generally poor air quality, especially when in combination with small room sues and the use of non-absorbent wall finishes, which are common today.

Radon routes into house The majority of houses in the UK do not have significant radon levels, although high levels do occur in certain areas. Guidance has been issued under Part C of the Building Regulations describing design solutions within affected parts of the UK. One approach is to provide a completely sealed floor so that no radon can be drawn into the house. See ‘Ventilation under floors’. See also pages 185-186.

Other indoor pollutants Other indoor pollutants may occur in houses from the building materials used; eg from coal tar products used as damp-proof membranes. There is no evidence that any of these occur frequently enough in sufficient concentrations to be unpleasant or to provide a health hazard. However, concentrations creating a health hazard have been known to occur, and these must be dealt with on an individual basis when encountered. Wood preservatives are subject to approval of the Health and Safety Executive under the Control of Pesticides Regulations 1986.

Non-gaseous indoor pollutants In order to eliminate minor or occasional health risks which are not at present covered by regulations, the BREEAM criteria give credit:

0 Either for using an alternative to man-made mineral fibre (MMMF) insulation materials, or for preventing fibres from becoming airborne within the living space (by boarding any loft area or enclosing all MMMF loft insulation in polyethylene), and for vacuum cleaning using a fine final filter after building works are complete

0 For designs which specify no use of asbestos and no use of paints which contain lead

Ventilation requirements Air change rates of between 0.5 and 1 per hour for the whole house are recommended. These can be obtained by using trickle vents, extract fans or whole house ventilation systems. This ‘controllable ventilation’ will maintain good air quality without wasting fuel. The objective should be to remove the main pollutants, particularly excess water vapour at source.

The Building Regulations for England and Wales (Approved Document F) set minimum ventilation standards for all rooms. Table 13 of Reference 38 provides further information.

Habitable rooms Habitable rooms must have an openable window (minimum area 1/20th of the floor area) and a trickle vent (minimum 4000 mm2).

Kitchens Kitchens must have a mechanical extract fan (extracting at a minimum of 60 litres per second, or 30 litres per second if in a cooker hood) which is operated intermittently and a trickle vent (minimum 4000 mm2) or a mechanical extract system which can operate continuously at one room air change per hour. The cooker hood should vent externally and not allow recirculation.


-

Trickle ventilators

Bathrooms and shower rooms Bathrooms and shower rooms must have a mechanical extract system (extracting at a minimum of 15 litres per second) operated intermittently.

Separate toilets Separate toilets must have an openable window (with a minimum area 1/20th of floor area) or a mechanical ventilation system (extracting at a minimum of three air changes per hour) operated intermittently (with 15 minutes minimum overrun).

Utility rooms There are no regulations covering the provision of ventilation in utility rooms. However, due to the likely generation of water vapour in these rooms, an openable window, trickle vent and humidistat controlled extract fan are recommended to combat condensation and mould growth.

Alternatively, whole house mechanical ventilation systems are allowed. Passive stack ventilation systems may be allowed, depending on the Building Control Authority.

Ventilation requirements for heating appliances that bum room air are covered by the Building Regulations for England and Wales (Approved Document J) and described on page 162 of this book. Note: The Regulations for Scotland and Northern Ireland vary slightly.

Trickle ventilators Trickle ventilators are unobtrusive openings in window frames which allow controllable background ventilation in a room with little danger of draughts and minimal unnecessary heat loss.

All types of windows (including skylights) can include trickle vents within the frame, or in the adjacent glass. A total trickle vent open area of 4OOO mm should be provided in each living room and bedroom in a typical dwelling. Larger than average rooms will require more ventilation and through- lounges should be treated as two rooms.

Some special trickle vents automatically reduce the open area depending on the wind speed, or respond to indoor relative humidity.

Vents may be controllable; for example, by a ‘hit or miss’ sliding system, swinging stops, screw down closers etc. They should be secure when partly open.

Through-the-wall ventilators may be used, but care must be taken to avoid cold bridging around the duct, and also to ensure that air entering the room does not cause cold draughts. Noise-attenuating versions are available for use adjacent to noisy roads, etc.

Figure 130


-


Figure 131

Where passive stack ventila~on is used, the BREEAM the following requirements: +

Passive stack in main kitchen (above main cooker if possible) and in main bathroom

Passive stack or extract fan in other kitchens, bathrooms, shower rooms, WCs, utility rooms

Design according to guidance given in BRE Information Paper .IP21/8945, to achieve an average air extract flow rate equivalent to 1-2 room air changes per hour

0 Confirmation from the responsible Building Control Officer that ' passive stack ventilation will be accepted as fulfilling Building Regulations ventilation requirements

Passive stack ventilation Passive stack ventilation is the name given to a system of vertical or near- vertical ducts running from the ceilings of the kitchen and bathroom to terminals on the roof. The ducts extract moist air from the 'wet' rooms of the house, venting it directly outdoors, by the stack effect (the movement of the air due to the differences in temperature between inside and outside) plus the effect of wind moving over the roof of the house.

The system works in conjunction with fresh air which enters the house via trickle ventilators, cracks and other openings. This may reduce the necessary use of the extract fans (although these may still have to be installed to comply with Building Regulations; in England and Wales, check with the Building Control Authority). A passive system will provide continuous ventilation as long as the temperature within the house is higher than that outside, although normally at a slow rate. Higher ventilation rates will occur when temperature differences are higher, as in winter, and when room temperatures rise, eg during cooking. Thus the system should be most effective when it is most needed. The wind also has a great effect on the air flow rate of passive ventilation systems.

System layout The layout shown in Figure 131 is suitable for most two-storey dwellings.

To maximise the stack effect, ducts should be as near vertical as possible (less than 45" to the vertical) and must be well supported.

The inlet of the kitchen duct should be positioned above the cooker, if possible, but consistent with the duct position in the room above. The two ducts should not be joined together.

The positioning of the outlet terminals is constrained by the need to ensure, as far as possible, that air flow in the ducts is not unduly affected by the prevailing wind speed and direction, or sudden changes in these. The preferred place for the ducts to terminate is at outlets on the roof ridge so that wind gusts and certain wind directions are less likely to affect performance adversely.

If the ducts run vertically, penetrating the roof away from the ridge, it is good practice to extend the duct above roof level to at least ridge height, in order to ensure that the duct outlet is in the negative pressure region above the roof.

Outlet terminals For duct systems which terminate on the ridge of the roof, standard ridge terminals with appropriate adaptors are suitable. Gas-flue ridge terminals may offer less resistance to air flow up the duct than other types. Where ducts do not terminate on the ridge, flue or soil-pipe terminals should be used. The design of the outlet terminal should be such that rain is not likely to enter the duct.

Internal grilles Grilles or terminals on the inlet ends of the ducts should present the least possible resistance to the flow of air and should be easy to clean. Most concentric-ring and egg-crate types are suitable.

'


Extractor fans and controls

Duct size and materials To achieve an adequate but not excessive flow rate of air, the diameter of the ducting should normally be between 100 and 150 mm. 'Off-the-shelf' PVC-U pipes and fittings, of the type used for drain-pipes, are suitable. Flexible ducting is more expensive but is easy to install, particularly in the roof space where access may be restricted. It is also available in insulated form.

Duct insulation The duct should be insulated to a thickness of at least 25 mm wherever it is run outside the heated part of the dwelling, eg in the roof space. This helps to maintain the stack effect and reduces the risk of condensation forming inside the duct and running back down into the dwelling.

Fire precautions A duct from the kitchen could act as an easy path for the transfer of smoke and fire to the first-floor living space. A quick-acting fire damper, such as a fusible link type, should be properly fitted close to the inlet of the kitchen duct below the ceiling or within the floor.

Extractor fans and controls Mechanical removal of stale or polluted air is effected directly by extract fans. Fresh air will at the same time be automatically drawn into the room from other rooms or the outside via trickle ventilators, cracks and other openings. All kitchens and bathrooms (even if adjacent to an external wall) are required by Building Regulations to have extract fans fitted or to be connected to a mechanical extraction system (see below) or passive stack ventilation system. Internal toilets also require extract systems, and toilets with external walls may be provided with extract fans as a substitute for an opening window.

Where an open-flued heating appliance is to be fitted in a kitchen, adequate fixed ventilation to outside must be provided, sized to accommodate both the extract fan maximum volume and the requirements of the heating appliance.

Type and location Extract fans can be fitted:

0 On an external wall, expelling stale air directly through the wall (cavity

0 On an internal wall, with a duct to outside through which to expel the

0 In a window, single or double glazed

0 In a ceiling, with a duct through the roof space to outside the house

must be closed tightly where the unit passes through)

stale air

In a kitchen the extract fan can be a cooker hood, the outlet of which should always be connected to outside either directly or via a duct. A recirculating system will not perform adequately and does not comply with Building Regulations.

All systems can work adequately so long as the location is correct in terms of air paths; choice will depend on room layouts and wall space available, etc.

BRE housing design handbook 177 ,


Figure U2a Kitchens: extract fan location

178

Extract fans should be located:

As high as possible in the room

0 As close as possible to the source of pollution; ie the cooker or hob in

So that the fresh air entering the room does not ‘short circuit’ the

Not directly above a cooker hob or where the temperature could rise

0 So that the control cord (if fiued) can be easily operated.

the kitchen, or the shower in the bathroom

source of air to be extracted

above 40°C (except in the case of cooker hoods)

Cooker hoods can be wall-mounted, fixed under cupboards or built-in as part of a canopy or special kitchen cabinet.

sizing Extract systems must be adequately sized for their function, as laid down in the Building Regulations.

The relationship between fan size and room air change rates can be calculated simply by multiplying the volume of the room by the air changes per hour to give the required capacity of the fan, eg in m3 per hour.

Control Extract fans in interior bathrooms and toilets should operate automatically on the light switch and have a minimum 15 minute overrun after the light is switched off.

All extract fans should also be operated (in addition to the above) by a humidistat controller. This causes the fan to run which keeps the humidity level in the room to an acceptable level. ‘Solid state’ sensors are preferred to the cheaper ‘plastic strip’ sensors, as they suffer less from contamination by grease, etc. Three systems can be used:

0

0

0

A

A built-in humidistat controller which turns the fan on and off in relation to a variable pre-set relative humidity level

A built-in humidistat controller which regulates the speed of the fan in relation to the difference between internal and external humidities. This allows good control of internal humidity with minimal energy use and minimal noise level, particularly on start-up when humidity levels are low

A remote humidity sensor and controller, operating as above. It is important to locate a remote sensor close to the main source of water vapour

manual ovemde switch to turn the extract fan on when required, should always be included.

The control must be wired so that the humidistat controller turns on the fan when required and that accidental manual control does not make the humidistat controller inoperable.


Extractor fans and controls

I I I I I I I I I I I

5 . 1

'p

Zone I 0.75 m I

7 /-p---4 - 1

'Landlord-controlled' extract systems In buildings containing several flats or maisonettes, a central extract system can be used, which draws air from kitchens and bathrooms in all units via ducts and a roof mounted fan. Such systems normally operate on a 24 or 18 hour basis and ensure reasonable levels of background ventilation in all units. The advantages are that individual humidistat controllers are eliminated and the likelihood of individual householders not using their extract system is greatly reduced. However, the systems require maintenance by the building operator to ensure continuous use. Information on the system should be brought to the attention of the occupants to stop them from tampering with the extract grilles.

Bath

I I

Bath

I . , I

I

Shower

Fans should always be installed outside the defined zones

Figure 132b Bathrooms: extract fan location

Duct arrangements Ducts from different flats must not be combined, due to the danger of reverse flow.

Ducts should be insulated to reduce the risk of condensation forming inside the duct as it passes through the cold air in the roof space.

" I I I

Figure 132c Ceilings: extract fan location



Mechanical ventilation systems and heat recovery To reduce the heat loss resulting from mechanical extraction of air from a house, the cold incoming air can be heated, by means of a heat exchanger, from the warm outgoing air. Heat recovery can be included in a whole house ventilation system or in conjunction with an extract / input fan.

Whole house ventilation systems The use of mechanical ventilation (MV) in dwellings is becoming more common, either:

as a balanced supply and extract mechanical ventilation with heat

as a mechanical extract ventilation (MEV).

recovery (MVHR), or

In both cases the air is collected or distributed through a duct network. An MEV system consists essentially of the extract components of an MVHR system.

The cost effectiveness of MVHR systems with respect to energy savings is not encouraging, however. A good reason for installing a full mechanical ventilation in dwellings (with or without heat recovery) is control of indoor pollutants, particularly water vapour.


_. . . -

ti 3295

Mechanical ventilation systems and heat recovery

- I

Where mechanical ventilation with heat recovery is chosen, the following criteria and recommendations, incorporated into BREEAM, are relevant.

Criteria 0 Supply to living rooms, bedrooms and other 'habitable rooms' such as

0 Exiract from rooms where moisture and odour usually produced (eg

0 Location of supply and extract terminals as specified in BRE

playrooms and studies.

kitchens, utility rooms, bathrooms, WCs).

Inforrqation Papers IP18/88& and IP21/8P5. * . . .

Recobendations 0 Sensible teplperature effectiveness of the hea

recovery unit should be not less than' 60% at the m flow rate. .

C "

0 ri/ririimum whole-home 'kr change rate'of betweenO.5'and 1.0 ?i.r changes per hour. . .

0 .For optimum operation the dwelling should be as practicable;,a mean background air infiltration ra more than'0.2 air changes per hour. .

0 h e total supply aii flow rate in an MVHR system-should be sekat 90

having a-greater effe to be eliminated by



Ductwork Ductwork must not allow the generation and transmission of noise. It must be airtight and capable of being cleaned internally. It must be insulated where it passes through unheated spaces.

Duct terminal fittings External intake and outlet positions must be covered in mesh against entry of birds etc and must be sited to avoid pollution. Inside the house, grilles must be sited to avoid short circuiting and draughts and where they will heat the whole room. Extract grilles should incorporate a dust filter and, when fitted in a kitchen, a grease filter.

Fan and MVHR unit siting The MVHR unit or MEV fan may be sited anywhere provided there is adequate access for cleaning and maintenance, and provided that any noise produced by the system will not disturb the occupants or their neighbours.

In some cases it may also be necessary to fit flexible couplings between the ductwork and the MVHR unit or MEV fan to prevent transmission of vibration.

Heat exchangers should be provided with a condensate drain.

System controls A master on/off switch should be mounted on or near the MVHR unit or MEV fan to isolate the system electrically during cleaning and maintenance. . ' . The system should include variable fan speed control and/or';ariable damper control to permit air extract boost during periods of cooking, showering or washing.

Fire precautions 0 Ducting connected to the cooker hood in the kitchen should be made of

steel. A fire damper is essential to close off the cooker hood's air extraction opening and should be as close as possible to the hood. Quick-acting fire dampers, such as a spring-loaded or gravity-operated flap with thermal release, are preferred.

switch should be fitted in the air extract system upstream of the MEV fan or MVHR unit. For plastics ducting (supply or extract) fire dampers should also be fitted wherever the duct passes through any floor and through those ceilings and internal walls which are required to be fire resisting.

0 For metal extract ducting, a fire damper and/or thermal fan cut-out

Instructions 0 It is essential that each MVHR unit and MEV fan is supplied with

comprehensive instructions for occupants.

Whole house ventilation systems can be operated in conjunction with warm air heating, and also with heat recovery systems.


Heat recovery extract fans

Heat recovery extract fans The principles of recovering heat from extracted air can also be used with individual extract fans. Small wall-mounted units incorporate cross flow heat exchangers and two fans so that air drawn into the room can be heated from the warm extracted air. This can produce up to 70% thermal efficiency, in terms of heat transfer between exhaust and incoming air, but average efficiency is below 50%. Capital costs are much greater than for extract systems and the heat exchanger requires periodic cleaning.

Exhaust air with heat removed

Figure 134

Heat exc..ange units are unlikely to be cost effective (taking into account the extra electricity used for a double fan system and for overcoming the resistance of the heat exchanger) except where exhaust air temperatures are likely to be high over a long period of time and where there is a requirement in the particular room for heating.

Ventilation for tumble driers Most tumble driers exhaust large quantities of moisture into the atmosphere and this can cause serious condensation problems if the exhaust terminates within the house. All houses should have a vent fitted through an outside wall (sleeved through the cavity) for tumble drier exhaust.



Ventilation of roof spaces At least equal to a continuous strip

[Consult the Building Regulations 1990, Section F for ventilation requirements]

'I 3 Figure 135a

At least equal to a continuous strip 10 rnrn wide

J I Figure 135b

At least equal to a continuous strip 25 rnrn wide

At least 50 rnrn +I k

I' * Ventilation of all roof spaces under cold-deck roofs is necessary for removing moisture which enters from the rooms below. Even if vapour control layers are provided in ceilings, some water vapour inevitably enters the roof space and must be removed.

31 V Figure l35c

At least equal to a continuous ' strip 5 rnrn wide

At least eaual to a /&

Figure 135d

184

Pitched and flat roofs should be ventilated as shown in Figure 135. All ventilation openings should be covered with 3-4 mm mesh to stop birds and vermin. Care should be taken that the mesh does not reduce the free area of the vent below that required.

It is important that the loft insulation does not block ventilation paths. Purpose-made components should be used, particularly at eaves, to hold quilts and loose-fill material in place.

In flat roofs and in those where the ceiling follows the pitch of the roof, more ventilation (0.6% of the roof area) is needed if a span exceeds 10 m or is other than a simple rectangle in plan. The void should always have a free air space of at least 50 mm between the roof deck and the insulation. Where joists run at right angles to the flow of air a suitable air space may be formed by using counter-battens.

Use an alternative form of roof construction (such as a 'warm roof') where the edges of the roof abut a wall or other obstruction in such a way that (a) free air paths cannot be formed to provide cross ventilation, (b) the movement of air outside any ventilation openings would be restricted.

At least equal to a continuous strip 25 rnrn wide At least

50 rnrn +IF c

5 rnrn wide 'A \>

' I ,'A1 least equal to a continuous strip 25 rnrn wide

Figure 1351


-4

Ventilation under floors

Ventilation under floors Suspended timber floors [Ventilation under suspended timber floors is required in the Building Regulations 1991, Approved Document C.]

A ventilated air space must be provided under all suspended timber floors, measuring at least 75 mm from the concrete to the underside of any wall plates and at least 150 mm to the underside of the floor.

Each external wall should have ventilation openings placed so that the ventilating air will have a free path between opposite sides’and to all parts. The openings should be large enough to give an actual opening of at least equivalent to 1500 mm2 for each metre run of wall. Any pipes needed to carry ventilating air should have a diameter of at least 100 mm.

Radon In areas where radon may occur [Precautions are required by the Building Regulations 1990, Approved Document C , to avoid danger to health from radioactive substances found under a house.]

In areas where radon may occur in higher than normal quantities, ground floors and walls built into hillsides should be constructed in accordance with any relevant Guidance issued under the Building Regulations.

For up-to-date information, contact the Building Research Establishment, Garston, Watford, Herts WD2 7JR.

The principles of protection against radon are to provide a continuous polyethylene membrane across the floor and walls and to provide the possibility for future mechanical extraction of radon from under the floor at a later date if this proves necessary.

Guidance is summarised for several types of floor construction.

The membrane The horizontal membrane should be at least 1200 grade polyethylene laid continuously from side to side of the building. Any joints should be well lapped to ensure a good seal. Services should not be brought through the membrane (most can enter through the walls). Where services must penetrate the membrane an airtight seal must be constructed. The membrane must not be punctured by rough fill or concrete. Blinding must be used to provide a smooth surface.

Underfloor ventilation Voids under all suspended floors (timber and concrete) must be ventilated to Building Regulations’ requirements for suspended timber floors.

Underside of floor

Suspended timber floor

I

A Wall plate =---;- A I ‘ DPC 1 ~~~~~ 175 At least mm I I Ventilated

I airspace 1 1 - Ground cover

Adjoining ground level re

Figure 136

185 ,--



Sub-floor depressurisation Where a floor is to be constructed without an underfloor ventilation space, a 100 mm pipe (or pipes) should be laid under the floor terminating in a radon sump in the centre of the house. The pipe should be capped to prevent the entry of rain, birds, insects or vermin. It should be possible at a later date to fit an extract fan to the exit pipe, which should not be located where a future riser would look unsightly.

The pipe should be taken through the wall footings under the membrane or up through the house to exit above the roof, although this should be avoided if possible because of the necessity and difficulty of sealing the membrane.

Q


Chapter 14

Services and drainage


Introduction Services form an ever increasing proportion of building costs. Careful planning could keep to a minimum the considerable expense involved with many services, such as below-ground drainage.

Dwelling layouts are often adopted without any consideration of how they may affect the overall drainage layout for the site, by making extra drain runs necessary. Site layouts are not always planned to take full advantage of the topography of the site; such planning could reduce expensive excavation costs. The benefits to be gained from applying the results of research are also either ignored or unknown.

This section deals with some aspects of sanitary plumbing and drainage which will lead to more economical layouts. Sanitary plumbing and below- ground drainage are sometimes designed by architects themselves. Although this section is not intended to be a comprehensive design guide, it should provide a helpful approach for the design of small housing developments.

Basic principles Requirements Plumbing systems are governed by sections in the Building Regulations 1991, which cover pipework and appliances. Advice and guidance on the design of plumbing systems is also available in British Standards, eg BS 5572, the Digests of the Building Research Establishment, and publications of the Institute of Plumbing.

The purpose of a sanitary plumbing and drainage system is to carry away waste products efficiently and quietly with the minimum risk of blockage and without permitting foul odours from the drains to enter the dwelling.

To prevent the escape of odours from the drainage system, water-sealed traps are used at each sanitary appliance. Large fluctuations in pressure in the pipework system can, under certain conditions, destroy the water seals; for this reason the pressures in the system should be contained within prescribed limits (+ 37.5 mm water gauge in order to preserve the integrity of the smallest water seals).

Excessive fluctuations in pressure can be avoided by venting of the system. Some large installations still sometimes use a system of ventilating stacks and branches connecting each appliance. Although installations of this type use a soil stack and a vent stack, they are referred to as ‘one-pipe’ systems. Variations on these systems have either the WC branch only vented, or simply a direct cross-connection between the two stacks. These are known as ‘modified one-pipe’ and ‘modified one-pipe - vented stack’ respectively.


Figure 138a Ventilated system

,-, r i

i U Figure 138b Modified single stack system

D

Figure l38c Ventilated stack system

.,--lt-,.

11 Figure 138d Unvented single stack system

1 PREVIOUS PAGE IS BLANK I 189 ~-


190

Provided certain principles are observed regarding the number of fittings connected, the lengths of waste and the diameter of discharge stack used, it is now established that a single stack serving as a combined soil-and-vent stack will be adequately self-venting for all domestic work up to 30 storeys. This is the system implicit throughout this section. The stack needs to be not less than 75 mm for two storeys, and not less than 100 mm for three storeys.

The single stack system has obvious planning and economic advantages when compared with the ‘one-pipe’ systems. A 150 mm single stack in a multi-storey block for example, requires considerably less space than a 100 mm soil stack and 50 mm vent stack system, and in many cases a 125 mm single stack would be sufficient.

Note that it is now possible to specify air admittance valves (AAVs) which avoid the need to take ventilation stacks through the roof space, although these should not be used if the more normal practice of using ventilating pipes to the stacks is possible. AAVs should be installed according to the manufacturer’s instructions. To aid clearance of blockages, AAVs should be removable.

Approved Document H of the Building Regulations 1991 permits AAVs only if they are subject to a current British Board of Agrement Certificate, and if the installation is in accordance with the terms of that certificate. The Technical Standards for compliance with the Building Standards (Scotland) Regulations 1990 also have restrictions on the use of AAVs.

Seal loss Seal loss can occur when variations in pressure in the stack overcome the head of water in the trap. The pressures result from water flow in the stack itself causing induced siphonage or back pressure. Seal loss can also occur when full bore water flow in the branch causes self-siphonage.

Seal loss from self-siphonage need not be a serious problem provided the recommendations on traps, length, diameter and inclination of waste branches are followed (see Figure 139 which shows basic principles).

Stack vents should terminate at such a height and position that foul air does not cause a nuisance or a health hazard. This will be achieved if the stack vent is not less than 900 mm above the head of any window or other opening into the building within a horizontal distance of 3 m. Stacks should also be positioned away from parapets and corners of buildings. Note that air admittance valves installed in accordance with manufacturers’ instruction may be used.

Bends at the base of the discharge stack should be of large radius, and preferably two 45’ large radius bends should be used. Alternatively the diameter of the pipe at the foot may be increased. Offsets in the wet part of the stack should be avoided.


- -1

Basic principles

Stack vents should terminate at such a height and position that foul air does not cause a nuisance or a health hazard. This will be achieved if the stack vent is not less than 900 mm above the head of any window or other openings into the building within a horizontal distance of 3 m. Stacks should also be positioned away from parapets and corners of buildings. Note that air admittance valves installed in accordance with manufacturer's instructions may be used.

t 600 mm

I

1700 mm maximum with 32 mm diameter waste --- 3000 mm maximum with 38 mm diameter waste

Slope in this section is determined by its length.

Where waste branch connections are directly opposite each other on the stack at similar levels, it is preferable !I to adjust their positions to exactly the same height to minimise the effects of cross flow.

Where the diameter of the waste pipe 1 800mm is increased to 38 mm it is advisable

to extend the tail of the trap by 50 mm

-L--______=u

I I in 32 mm diameter pipe. --- I f 1 1

50 mm parallel junction to be introduced only when the bath waste would otherwise enter the stack below the WC branch connection centre line and within 200 mm.

2300 mm maximum with 40 mm diameter waste


I b

Waste branches Maximum length shown on this sheet should not be exceeded unless the traps are vented.

Waste traps For this single stack system, deep seal 75 mm traps must be fitted to waste outlets.

In flats with more than five storeys all sanitary appliances on the ground floor should be connected directly to the manhole.


4000 mrn maximum with 50 mm diameter waste

Permitted slopes given in Figure 141.

7 mm

- - 1500 mm maximum length of branch

The WC branch connection should be swept in the direction of flow with a 50 mm minimum radius at the invert. 50mm

Soil and vent stack Bosses for waste pipes facilitate production when set at a constant slope of 92.5 degrees.

Offsets below the topmost connection should be avoided.

Bends at the base of the discharge stack should be of large radius and preferably two 45 degree large radius bends should be used. Alternatively the diameter of the pipe at the foot may be increased. Offsets in the wet part of the stack

In flats with more than twenty storeys all sanitary appliances on the ground floor and first floor should be connected directly to the manhole.

should be avoided.

9 Figure 139


- . -


Flow and usage data of some sanitary appliances ~ ~~ ~

Maximum Duration Minimum Individual discharge of interval probability @) Discharge

Specified rate discharge, of discharge, of discharge, unit Appliance capacity ( I s 1 ) t (9 T (s) p = t/T value

W L

Washdown WC with low or high level cistern

Washdown WC with close coupled cistern

Washdown WC fitted with a macerator

Wash basin (32 mm branch)

Sink (40 mm branch)

Food waste disposal unit

Bath (40 mm branch)

Spray tap basin

Electric shower

Low pressure shower (per spray head)

High pressure shower (per spray head)

Automatic washing machine

Dishwashing machine

7.5 I*

6

7.5 I*

6 I*

7.5 I*

6 1

6 1

23 1

-

80 1

-

7-8 kW

c 0.6 bar head

< 0.6 bar head

4-5 kg dry load

12-14 place

settings

1.8

1.8

1.2

1.2

0.4

0.4

0.6

0.9

0.2

1.1

0.06

0.07

0.15

0.15-0.35

0.6

0.25

6.4

6.2

8

6.5

30

29

10

25

90

75

-

300

300

300

30

20

1 200 600 300

1 200 600 300

1 200 600 300

1 200 600 300

1200 600 300

1 200 600 300

1 200 600 300

1 200 600 300

1500

4 500 1 800

-

1 200 86 400

1 200 86 400

1 200 86 400

0.0053 0.0107 0.0213

0.0052 0.0103 0.0207

0.0067 0.0133 0.0267

0.0054 0.0108 0.0217

0.0250 0.0500 0.1000

0.0242 0.0483 0.0967

0.0083 0.0167 0.0333

0.0208 0.0417 0.0834

0.0060

0.0167 0.0417

-

0.0250 0.0035

0.0250 0.0035

0.0250 0.0035

240 (Note 1) 0.1250 900 0.0333

15 000 0.0200

180 (Note2) 0.1110 I 200 0.0166

86 400 0.0002

6 12 24

6 11 23

4 7 14

3 6 11

Less than 1

Less than 1

1 3 5

7 13 26

7 17

Less than 1

Less than 1

Less than 1

Less than 1

3

Less than 1


L-- -

Basic principles

Requirements for the discharge rates from appliances should be a primary consideration of the designer. Typical discharge rates for the UK are listed in the table opposite. The sizes of outlets, traps and pipework should be such that the discharge from sanitary appliances is not unduly restricted below such values. Pipes serving more than one appliance should be sized taking account of simultaneous discharge. The table also gives information on the duration and frequency of use of appliances that may be used in calculations of simultaneous discharge. A value of 99% is recommended as a minimum criterion of satisfactory service for such calculations.

The data used in this table were correct in 1990. Subsequent changes in appliance design and usage may need to be taken into account in the future.

Notes for table opposite Note 1: A washing machine will discharge at various intervals during any selected programme. The maximum number of discharges will be 6 and the volume discharged each time will be in the order of 20 1; hence:

240 s represents the minimum time between rinses 900 s represents a mean discharge interval of 15 minutes during the use of the machine 15 000 s represents a 4.2 h interval between uses of the machine.

Note 2: A dishwasher will discharge at various intervals during any selected programme. The maximum number of discharges will be 5 and the volume discharged each time will be in the order of 6 1. Hence:

180 s represents the minimum time between rinses 1200 s represents a mean discharge interval of 20 minutes during the use of the machine 86 400 s represents daily use of the machine

The above data apply to 1990 models. Older machines will generally discharge greater volumes at lower flow rates for longer periods; eg a 1970s washing machine would discharge at about 0.1 l/s for around 3 minutes.

Maximum capacity and number of discharge units for vertical stacks

Size Capacity of stack Number of (mm) (W discharge units

75 3.4 200 100 7.2 750 150 21.7 5500



n

Figure 140 Stub stack

Stub stacks A stub stack consists of a short straight 100 mm discharge stack with the top closed, preferably with an access fitting. It can be used to connect various appliances providing the total loading does not exceed 17 discharge units (see table on page 192), and the centre line of the topmost connection is not more than 2.5 m above the invert level of the drain or branch discharge pipe. Where one or more stub stack connections discharge to a drain, the head of the drain should be ventilated by a ventilating stack or discharge stack that terminates externally to the atmosphere.

Showers Flow rates from single head showers are small so that the 40 mm discharge pipe usually fitted does not require venting. However, difficulties may arise in achieving a self-cleansing velocity and adequate provision should be made for cleaning. Multiple shower heads may produce considerable flow rates.

Limitation of noise Noise generated by discharge systems should be limited so as to maintain environmental quality in the dwelling. The discharge from sanitary appliances and pressure fluctuation in the pipework causing loss of seal are important sources of noise, but those systems designed to limit pressure fluctuations will tend to be quiet. Noise may be reduced by sound insulation of the pipework from the structure and containing ductwork. Correct fixing of pipework will contribute to noise limitation.

Thermal movement The movement caused by thermal changes in pipework requires special consideration, and therefore adequate provision for expansion should be made, especially with pipes made of plastics and copper. Where pipes of these materials pass through solid walls and floors, sleeves should be provided.

Plumbing design The effect on self-siphonage of the length, diameter and slope of waste pipes to washbasins is particularly important as the usual 32 mm diameter waste pipe normally runs at full bore. Where the pipe is not ventilated, it is necessary to limit the length and slope of this pipe (see Figures 141 and 142).

Washbasins, unlike baths and sinks, do not have a beneficial final slow ‘tailing off‘ when emptying, that is to say a progressive reduction in the flow, ending with a trickle. When selecting washbasins it is therefore advisable not to choose a model which is too funnel-shaped, but at the same time to bear in mind the type of terminal water fitting to be installed, since too flat a base could give rise to splashing in some situations. It will be noted that the above comments apply to the use of ‘P’ traps. ‘S’ traps are liable to severe siphonage which may require additional venting as in one-pipe systems. Risk of seal loss from induced siphonage depends on the number of appliances connected, the profile and diameter of the branch connections, the height of the stack and its diameter.


- - -

Plumbing design

Sinks and baths are normally fitted with 40 mm discharge pipes. Self- siphonage is not a problem because of the trap seal replenishment which occurs at the tailing off at the end of the discharge due to the flat bottom of the appliance. The tailing off results from the flatter bases to the bowl shape of these appliances; they should be sufficiently inclined to prevent scum deposits but at the same time empty slowly enough to ensure refilling of the trap. Therefore, the length and slope are not so critical and venting is not normally required, although the maximum length should be restricted to 3 m to reduce the likelihood of blockage from deposits. (Slope 8 between 1 and 5 degrees, length L less than 3 m).

Domestic washing machines and dish washing machines normally have a 40 mm discharge pipe, which can be connected either directly to a discharge stack or gully, or to a sink branch pipe. Normally a trap should be fitted in the horizontal section of the discharge pipe, but this is not required for connections via a sink branch pipe, when made at the inlet of a sink trap using a suitable fitting.

WC branch connections should be swept in the direction of flow with a 50 mm minimum radius sweep. Single WC branches of 75 or 100 mm size do not require venting whatever the length or the number of bends included in the run. Bends should have as large a radius as possible to prevent blockage, however. Slope should be greater than 1".

For each diameter of stack there are limitations in height and in the number of appliances which can be connected before risk of seal loss necessitates additional venting, by a separate vent stack or a larger soil and-vent stack.

The designs of bathrooms and kitchens illustrated in this publication have been prepared with emphasis on user requirements. An 'activity space' for each appliance based.,on ergonomics and user studies has been determined and the various activity spaces related to each other in their likely combinations to give layouts which provide satisfactory solutions in terms of space and engineering performance.

I Maximum I I I I I I I I

0.5 0.75 ,1.0 1.25 1.50 1.75 Length beween trap weir and vent. L (m)

Figure 141

n I * I

32 mm branch discharge pipe 75 mm seal depth 'P' trap

Figure 142

BRE housing design handbook 195 -, -

Services and drain age

-2200- E-

forsoil stack $34 D r- rn Alternative position

o -++ 700 + 4 4 0 w

Common dimensions A 254 mm for parallel tub baths

275 rnm for rectangular and shallow baths 285 rnm for rectangular and magna baths

B 178 mrn for 500 mm x 400 mm washbasins 100 rnm for 450 mm x 300 mm washbasins

C 300 mm for P traps (approx.) 345 mm for Straps (approx.)

D 100 mm minimum E 1200 mrn maximum

Figure 143a Combined bathroom and WC

160-k 100

Figure 143b Bathroom and separate WC

1,1500--- 3-

1300

Lt&Y Figure 143c WC and washbasin

Figure 143 Sanitary plumbing layout

196

Diagrams on this page and the next page indicate suggested dimensions for setting out appliances and space requirements for service ducts.

There are also specific points of plumbing design which help when designing simple and economical plumbing layouts. The soil stack, for example, should ideally be located directly behind the WC in a duct. If this is not possible because of the position of windows or the WC flushing cistern being located in the duct, for example, or simply because there is a lack of space behind the WC for the duct, the stack should be placed to one side as near to the WC as possible and between the WC and other appliances - particularly the bath. This design point is important in situations where horizontal outlet WC pans are used, as the bath waste is virtually impossible to connect without using special fittings which increase the cost of the installation.

With the development of internal plumbing, care is required in siting stacks and waste branches to minimise nuisance from noise and from sound transmission where the fitments are adjacent to sleeping or living areas.

1

Figure 143d Figure 143e WC and washbasin WC and washbasin


.. . -

. -

I , ..

Plumbing design

1 1 1

Duct size 2200 x 200 mrn Duct size 700 x 200 rnm Duct size 1500 x 200 mm

f 1900

f 1700

f 'i

Duct sizes 1600 x 200 mm 800 x 200 rnrn

Duct size 800 x 200 rnm Duct sizes 900 x 200 mrn 800 x 200 mrn

160- 130-

i 1900

f 1700

Duct size 800 x 200 mrn Duct size 900 x 200 mrn

Duct size 2200 x 300 rnm

f i

1800

Duct size 800 x 500 rnrn

1 6 0 0 - q

1

Duct size 800 x 200 mm

f 1400

I t l ' 1

Duct size 700 x 200 mm

Duct size 900 x 200 rnrn

0

fl-7 uu Walk-in duct of size 2200 x 600 mm

Figure 144 Sanitary plumbing layouts and ducts


Services and drain age

Details Waste pipes Waste-pipe runs should be kept as short as possible. Kitchen-sink wastes are particularly liable to build up deposits. The deposits from kitchen-sink wastes also appear in stacks, but on stacks taking other appliance wastes as well as sink wastes, the effect of deposit build up is not as marked as in stacks taking kitchen-sink wastes only. The latter have an abnormally high build-up of deposits, making them more susceptible to blockage.

Offsets Offsets on the main stack above the topmost connection have little effect on the performance of the system, but offsets below the topmost connection can give rise to back pressures and should be avoided; otherwise vent pipes may be required to prevent such pressure fluctuations in the stack.

The base of the stack The bend at the base of the stack is a critical point in a plumbing system. Unless properly designed it can give rise to blockages, back pressures, or build-up of detergent foam.

Large-radius bends, preferably composed of two 45'. bends, are essential, but even when using a one-piece bend the radius of the bend should be as large as possible, and should never be less than 200 mm at the centre line.

In single, two, and three-storey houses, the vertical distance from the lowest connection to the invert of the drain or tail of the bend should be 450 mm minimum. For low-rise flats up to five storeys, with ground floor appliances connected into the main stack, this dimension should be increased to 750 mm minimum.

It may be preferable to connect ground-floor fittings separately to the manhole, or use stub stacks.

For high-rise development up to 25 storeys the 750 mm dimension still applies, but from five to 20 storeys the ground floor appliances should be separately connected to the manhole, and above 20 storeys both the ground and first floor appliances should be connected directly to the manhole. An alternative method is to use a bend at the base of the stack one size larger in diameter than the stack, but this could necessitate increasing the drain diameters for the remainder of that section of the layout.

Provision for maintenance Access should be provided to enable all pipework to be tested and maintained effectively. The access covers, plugs or caps should be sited to facilitate the insertion of testing apparatus and the use of equipment for cleaning and/or the removal of blockages. Their use should not be impeded by the structure or other services. Access points should not be located where their use may give rise to nuisance or danger if spillage occurs. This can be mitigated if they are above the spill-over level of the pipework likely to be affected by a blockage and/or are extended to suitable positions at the face of the duct or casing, or at floor level. On


- -

Details

-E+=----

. I Access point

- - - - - - Access to stacks at three-storey intervals or less

- - - - -

easy removal

Figure 145

discharge stacks, access should be provided to the stack at intervals of not less than three storeys.

All access positions and inspection covers should be readily accessible and have adequate room around them for the use of cleaning rods. Provision for cleaning over and above the ability to disconnect the waste at pipe junctions, should also be made at long waste branches. Consideration should also be given to access for replacement of pipes which may become damaged.

Wind effects In high-rise building, suction and turbulence from wind blowing across the top of stacks has been known to cause seal loss in traps. Stacks positioned near corners or close to parapets are particularly susceptible and these positions should be avoided. Protective cowls on the stacks of tall buildings may sometimes be of assistance.

BRE housing design handbook 199 - - ~. . -


Materials for above-ground drainage The Building Regulations 1990 require that materials selected for pipework systems must be resistant to corrosion and not affected by atmospheric conditions. Recommendations regarding choice of materials are also made in BS 5572.

There are a number of materials suitable for sanitary pipework, but those currently in common use for domestic work are cast iron, copper, galvanised mild steel, and plastics.

In some local authority areas the use of particular materials is restricted so it is advisable to clarify the position at an early stage in the design.

In some pipework systems more than one material may be used, but the use of dissimilar metals in the same system should take account of the effects of electrolytic corrosion. The list below shows the relationship of metals. Where dissimilar metals must be used, neoprene or similar non- metallic connectors should be used.

This list shows the effect of combining metals - the upper named metal will be attacked by the lower. The closer the metals are in the scale, the lower the risk of attack.

Zinc Iron Lead Brass Copper and stainless steel

Cast iron pipes to BS 416 The durability of cast-iron pipework depends on the protective coating, and the pipes should be examined carefully before installation to ensure the protective coating is undamaged. The introduction of flexible joints has considerable advantages in labour costs over the previous hemp and lead joints. Cast-iron pipes may be fixed satisfactorily by using:

0 Fixing lugs on the pipe sockets

0 Cast iron, malleable iron or steel holderbats for building-in, nailing or

Purpose-made straps or hangers

screwing to the structure

Copper tubes to BS 2871 Copper tubes are available in long lengths, which reduces labour costs. Copper plumbing assemblies are very suitable for prefabrication techniques. Jointing is by brazing, or compression or capillary fittings. Fixing is by use of

Copper alloy holderbats for building in or screwing to the structure

0 Strap clips of copper, copper alloy, or plastics, or purpose-made straps or hangers

Copper tubing is also available to Table X of BS 2871:Part 1 but as this type cannot be bent or welded it may prove unsuitable for sanitary plumbing installations.


- I

Materials for above -ground drainage

Galvanised mild steel tubes to BS 3868 The component parts of pipework in this material should be hot dip galvanised after manufacture. Cutting of pipework on site should be avoided as this destroys the galvanising protection at critical points in the system; for this reason, assemblies are generally prefabricated. Painting of heavy galvanised pipes is particularly necessary where these are located in service ducts. Where galvanised mild-steel pipes pass through floors or walls they should be protected by a suitable tape or waterproof paper wrapping or should be painted with bitumen to prevent attack by Portland cement, lime, plaster, brickwork and magnesite.

Galvanised steel tubes may be fixed by:

0 Malleable iron brackets for building-in or screwing to the structure

0 Malleable iron pipe rings with back plates or girder clips

0 Purpose-made straps or hangers

Plastics pipes Pipes for soil and waste systems are manufactured in a number of thermoplastics materials including unplasticised polyvinyl-chloride (PVC-U), modified unplasticised polyvinyl chloride (MUPVC), high density polyethylene (HDPE), polypropylene (PP) and acrylonitrile butadiene styrene co-polymer (ABS). All are light in weight, easy to handle and highly resistant to corrosion. Attention should be paid to expansion in the system as the coefficients of expansion of plastics are much higher than for metals. Horizontal runs of plastics pipe require more support than metal pipes. Plastics material exposed to direct sunlight may require protection to resist ultra-violet degradation. It is advisable to seek guidance from manufacturers of any materials other than PVC-U or MUPVC. Also, some solvents or organic compounds can damage plastics materials.

ABS, high and low-density polythene and polypropylene and modified PVC are sometimes suitable for use at higher temperatures but manufacturers should be consulted on the appropriate choice and grade.

PVC-U is the most commonly-used plastics material for domestic discharge pipes but should not be used in applications where large volumes of water above 80°C are discharged, eg in dwellings where boil- wash programme washing machines or water-heating appliances without thermostatic control are used. Jointing is by solvent welding, which necessitates adequate expansion joints in the system, or by rubber ring sealed joints.

Care is required when installing PVC-U pipes in cold weather because the material becomes brittle at low temperatures. Pipes may be fixed with holderbats of metal, plastics-coated metal, or suitable plastics material. Care should be taken to ensure that the clip does not bite into the external surface of the pipe when tightened. Intermediate guide brackets fitted to the pipe barrel should allow thermal movement to take place. In multi-storey dwellings, vertical pipes should be supported by metal brackets because of their greater fire resistance.

Plastics pipes in most cases should be installed in ducts having a fire resistance equal to the building.



Ducts Refer to BS 5572 for advice and guidance on the design of service ducts. Ducts should provide ready access for maintenance, cleaning and testing. They should be constructed appropriately for fire resistance, for sound insulation and to limit the spread of vermin.

Discharge pipes in ducts with high ambient temperatures are likely to 'dry out' between discharges if the flow in the pipe is small and intermittent. This might cause a build-up of deposit in the pipe and bring about a pipe blockage. The ambient temperature in the duct should be controlled to prevent this from happening. In situations where the discharge pipe is receiving hot water, high ambient temperatures will inhibit heat loss through the pipe wall. Consideration should be given to insulating discharge pipes. Pipes passing through walls or solid floors, should be sleeved and fitted with suitable fire stops where appropriate.

The space required for the casing-in of service areas to form ducts depends on the diameter of the pipes or stacks to be cased and the thickness of the 'casing structure or materials. Figure 143 shows some suggested plumbing layouts and Figure 144 indicates overall duct sizes. These ducts can accommodate normal requirements for services, but for unusual requirements the advice of a services engineer should be sought on detailed duct layout.

Table of maximum distances between pipe supports

Vertical Low Pipe size pipes gradient

Pipe material (mm) (m) pipes(m)

Acrylonitrile butadiene styrene

Cast iron

Copper

Galvanised steel

Polyethylene

Modified unplasticised polyvinyl chloride

Polypropylene

Unplasticised polyvinyl chloride

32 40 50

All sizes

25 32 to 40

50 65 to 100

25 32

40 to 50 65 to 75

100

32 to 40 50

32 to 40 50

32 to 40 50

32 to 40 50

75 to'100 150

1.2 0.5 1.2 0.5 1.2 0.6

3.0 3.0

2.4 1.8 3.0 2.4 3.0 2.1 3.1 3.0

3.0 2.4 3.0 2.7 3.1 3.0 4.6 3.7 4.6 4.0

1.2 0.5 1.2 0.6

1.2 0.5 1.2 0.6

1.2 0.5 1.2 0.6

1.2 0.5 1.2 0.6 1.8 0.9 1.8 1.2


Economies

Even in simple duct layouts it should be remembered that where the spaces include soil stacks, allowance should be made for overall socket sizes which vary considerably according to the material used. A 100 mm diameter cast- iron soil stack, for example, requires a space of 160 mm x 160 mm to accommodate the socket sizes. A 150 mm diameter cast-iron stack requires 215 mm x 215 mm. Clearance is also necessary around a stack for jointing, etc. Space should particularly be allowed on the wall behind the stack for water and gas pipe runs and possible electric cables. Stacks in other materials require less space because of their smaller overall socket sizes. When planning bathrooms and ducts to a preferred increment of 100 mm, the areas required are often the same as those for the larger socket pipe.

For a 100 mm diameter stack in cast-iron, the width of space is 200 mm minimum and for 150 mm diameter stacks, 250 mm minimum. Where the duct casing is of thin material and little space is required for framing to the casing, the 200 or 250 mm overall width mentioned above may be wide enough to include the casing construction, but in many cases the duct will be formed in heavier constructions 50,75 or even 100 mm thick. In these cases, the overall duct-width should be increased to the nearest 50 or 100 mm increment to about 250 or 300 mm overall.

Economies Economies in plumbing system design Careful planning of appliance position and pipework leads to considerable economies, not only in materials but in space. The additional pipework required in the systems with all appliances vented is considerable when compared with single stack in the same circumstances. Considerable savings are also possible in some cases by the use of ‘back-to-back’ planning and by the use of multi-branch fittings available from some manufacturers. In cases where this technique is possible the number of stacks and service ducts is halved. Multi-storey developments lend themselves ideally to this type of installation because of the repetitive planning. Maintenance is easier where the ducts can be located opening onto a public access corridor. Examples are shown in Figure 144.

The connection of appliances from two horizontally adjacent dwellings into the same stack should be used only in situations where the stack is in a common service duct, and never directly through the separating wall. It is important to maintain adequate sound insulation between dwellings and special attention should be made when common service ducts are used.

Standardisation can also reduce costs in plumbing, even in mixed developments with flats, maisonettes and houses. Standardisation on one o r two bathroom layouts, for example, would allow pipework to be pre-cut and a high degree of prefabrication, thus reducing waste, cutting and man- hours on the site. Even service duct layouts could be standardised on the lines of those shown in Figure 144.

Considerable savings in man-hour requirements can be made by designing the plumbing to allow complete separation from other trades in order to avoid the situation of trade waiting upon trade. By careful detailing and selection of kitchen and other fittings it should be possible to plan a plumbing installation so that all work can be completed in two visits; the first one for carcassing immediately before plastering or wall-lining, and

BRE housing design handbook 203 _. - .


the second one for surface-run pipework and for fixing the fittings before decorating and installation of pre-finished joinery.

Combined drainage systems Stacks can in appropriate circumstances (those areas permitting combined drainage systems) be used both for accepting discharge from appliances and also collecting rainwater from roof areas, but there are potential dangers. Rainwater pipes are not permitted to receive foul or waste discharges. The rainwater outlet should be trapped unless it is in a position where termination of a stack vent is permitted. In very long stacks, eg a 30-storey building, quite small continuous flows of rainwater can cause excessive pressure fluctuations. There is also a danger of flooding if a blockage occurs in the discharge stack or underground drain during a heavy rainstorm, especially if the roof area is very large.

Where the discharge unit method (see BS 5572) is used as a basis for the design, the roof area drained of rainwater should be not more than 40 m2 per stack, and the building should be not higher than 10 storeys.

Ventilating stack I 'Thermal insulation

U U

Figure 146 Consideration should be given to insulating stacks and vents thermally to prevent the formation of condensation

Drainage services Food waste disposal units Special precautions are necessary where food waste disposal units are connected to a discharge system, and any manufacturers' recommendations on installation should be considered.

Always fit a tubular (not bottle or resealing) type trap, which is easily accessible for cleaning. A discharge pipe from such a unit should be not less than 40 mm diameter, and should be as short as practicable, connecting directly to a main discharge pipe of stack. The discharge pipe gradient should be at least 7.5" (135 mm/m) to the horizontal, although steeper gradients are advisable, and any bends should be of large radius. It is an advantage if other appliances can be connected to the discharge pipe upstream of the waste disposal unit connection, to assist transport of the waste material. The discharge pipe or stack should connect directly to a drain without an intervening gully or trap.


Drain age services

Drainage There are three types of drainage systems for the disposal of foul and surface water - combined, partially combined, and separate.

Excessive loading on sewage purification plant in seasons of heavy rainfall has led to the increased use of the separate system, and this is the one normally used.

Since the separate system involves two pipework layouts, it is essential that care is taken with the initial design to obtain the greatest economies. Site layouts should take account of the topography and contours of the site to ensure the most economical routing of sewers and drains, which incur high excavation costs. Seemingly minor changes in design and layout can have considerable effect on drainage costs.

The aim of a good design is to minimise the amount of excavation, the number of manholes, the total length of drain and the number of connections to the main sewers, while producing a system which is hydraulically sound with a low risk of blockage.

Foul drains - general At the building design stage the designer should endeavour to group the sanitary appliances in bathroom and kitchen as close as possible around the soil stack and within the limits set on waste branch lengths shown in Figures 141 and 142. This will avoid running foul drains on more sides of the house than necessary.

Where kitchens and bathrooms are sited remotely from each other, additional drainage to connect the remotely placed appliances is expensive.

Surface water drains - general Surface water drainage in the separate system is designed to carry surface water from roads, paths, hard standing and other impervious areas, in addition to water from roofs of dwellings and other buildings.

Buildings with pitched roofs necessitate surface drain runs on more than one side, but mono-pitched roofs, and sometimes flat roofs, can be serviced with one run of drain. In some cases, such as buildings with flat roofs or with valley gutters, it is possible to discharge some rainwater from the roofs into the soil stacks but the local authority should be consulted on this point at the earliest design stage.



STORAGE OF RECYCLABLE MATERIALS To encourage recycling of domestic waste on a larger scale, and to increase the utility of non-renewable resources, the BREEAM criteria call for:

0 a set of four containers for household waste, space for them and appropriate access for removal to a collection point.

The specification to be as follows:

at least four bins to be provided which are distinctly identified as being for different purposes (eg different colours) and have a total capacity of at least 240 litres (0.24 cubic metres) per household;

0 bins shown on drawings to be in a suitable hard standing space within 3 metres of an external door of a single-family house and within 10 metres of an external door of other dwellings;

0 in order to accommodate the possibility of additional bins being required in the future, the bin storage space must normally be at least 2 square metres in size, without interfering with pedestrian or vehicle access;

least two sides by a wall, fence or suitable hedge at least as high as the tallest bin,

0 access from bins to a place where a car or refuse collection vehicle can be brought, within 20 metres of the location of the bins.

0 bins protected from wind on at

Refuse disposal systems Communal refuse systems In multi-storey housing schemes refuse disposal systems must be convenient to use and easily accessible for users and for those collecting refuse.

Hoppers Access to hoppers which serve refuse chutes must be unobstructed. The clear space in front of hoppers should be not less than 1.5 m deep.

The preferred height of hopper hinges is 0.6 m above floor level. It can be useful to have a shelf on which rubbish may be placed before disposal; this should be adjacent to the hopper at the level of the hinge. Access to any supplementary refuse store, which is to be used for dry goods too bulky for disposal by chute, should be without steps.

The increasing volume of domestic waste has caused problems of overflowing on some estates.

Dustbins It should be possible to get to the location of refuse disposal under cover and preferably without steps.

Domestic refuse disposal arrangements vary widely according to the policy of the local authority. Some use large wheeled bins, others plastics bags on frames. Whereas in former years the domestic dustbin was a standard article, the situation no longer obtains. Where old style dustbins are still in use, the unobstructed area in front of dustbins should be minimum 1.2 m (deep preferred dimension 1.5 m).

Water services Fittings generally Water connection charges are related to the ‘rating’ of specific water-using fittings. Designers need to consider more carefully than in the past the economics and appropriateness of fittings. See box on the next page for BREEAM criteria.

Isolating valves (stopcocks) Stopcocks must be easy to manipulate and located in accessible positions. Access to stopcocks should be considered when pipe-runs are planned. Drain-down of the system should be possible.

Thermostatic valves, water heaters The temperature of water from a hot water cylinder should be thermostatically controlled, to minimise the risk of injury caused by scalding water. Thermostatic valves may be provided for individual fittings but the temperature is preferably controlled at the point of supply. The temperature at the supply point, which is dependent on the length of draw-offs, should be between 43°C and 5VC, giving a temperature at the point of delivery of approximately 40°C. Delivery rates should be not less


Electrical services

than 0.15 litredsecond at all points, with a preferred rate of not less than 0.30 litres/second at the bath.

Immersion heaters The immersion heater on/off switch should be easily accessible.

Boiling water heaters A boiling water heater adjacent to the sink can replace the use of kettles. These devices are not in common use, but may have specialist applications; for example, for use by some people who find the lifting of kettles difficult and hazardous.

Shower valves Shower fittings must have thermostatic mixing valves to avoid scalding and allow an accurate control of temperature, even though this is not required by legislation.

An alternative to a thermostatic mixing valve is an electric shower heater which is fed from the cold supply and thermostatically controlled. Note that they may be more expensive to use than showers fed from the main hot water supply.

Cold water supply A preferred delivery rate of not less than 0.20 litres/second is suggested at all draw-off points, with 0.30 litreshecond at the bath.

Storage systems There is currently a shift in common practice from storing comparatively large quantities of cold water, to using systems fed directly from the mains. Where potable cold water storage is used, it may be necessary to sterilise the system before use. Hot water storage capacity depends on the recovery capacity of the heating appliance and the amounts of water needed within short periods of time.

In some domestic systems, particularly large ones, it may be necessary to consider precautions against bacterial multiplication.

EIectricaI services Location of light switches All light switches must be conveniently located. Switches by doors should be horizontally aligned with door handles so that the locating of the switch relies on its direct relationship with the door handle. The recommended fixing height of light switches is 1.04 m above floor level. The level of 1.04 m is fixed by the position on all standard doors of the lock/latch. For accessible housing, the door handle preferred height is 900 mm.

To reduce wastage of water, which is a valuable resource, and to increase awareness of its importance, BREEAM criteria call for at least one of the following:

0 all WCs to have a maximum

a rain-water collection butt.

flushing capacity of 6 litres or less;

The butt should be:

at least 1 litre in capacity for each square metre of land allocated to the dwelling (either uniquely alIocated or shared with neighbouring dwellings) which is either planted (including grass) or left as unplanted soil;

minimum of 60 litres per dwelling (for a single-family house or flat);

a maximum of 350 litTes and a

without open access at the top;

provided with a tap for drawing off water;

0 connected to the rain-water down- pipes with automatic ovefflow into the conventional rain-water drainage system;

0 detachable from the rain-water down pipe, with a removable top or base for cleaning the interior.

Ceiling switch cords Knob pulls for ceiling switch cords should be at 1 m above floor level. Where for any special reason a higher position is preferred, the pull should be at maximum 1.5 m. Ceiling switch cords beside walls should pass



through a screw eye, as the user may have difficulty catching hold of a swinging knob pull, particularly in the dark.

Light switches Rocker action switches are recommended. To permit easy manipulation, switches should be as wide as possible; a width of not less than 0.01 m across the dolly is suggested.

Illuminated switches An illuminated switch or surround identifying the switch position can be helpful for finding switches in darkness.

Multi-gang switchplates Not more than two switches should be grouped together, since multi-gang switchplates can be confusing to the user.

Supplementary switches Two-way switches and intermediate switches should be provided.

Socket outlets: general considerations There should be an ample provision of socket outlets. The provision recommended as desirable thirty years ago in the Parker Morris report Homes for today & romorrow l1 was as follows:

Working area of kitchen Dining area Living area First (or only) double bedroom Other double bedrooms Single bedrooms Hall or landing Store/workshop/garage

Current minimum requirements for NHBC dwellings are the same with the exception of living room 4 and utility room 2. These figures should be treated as absolute minima, and can now advantageously be doubled, bearing in mind the proliferation of electrical appliances in the home. To minimise the need for adapters, twin or triple socket outlets are recommended where more than one appliance may be connected.

Location of socket outlets Socket outlets must be carefully positioned where they are most needed Where there are two sockets in a room, they should preferably be placed on opposite walls. Socket outlets in low positions which are difficult to reach may be hazardous.

Some authorities argue that socket outlets should be at the same level as light switches and door handles, ie at approximately 1.04 m above floor level and lower in the case of accessible housing. While lower fixing heights may be preferred in some situations, this is not yet standard practice in the industry; it is suggested that no socket outlet should be lower than 0.5 m above floor level. BS 5619 recommends a 300 mm minimum.


Electrical services

Kitchens Socket outlets over kitchen worktops may be difficult to reach. Consider a location on the fascia of the worktop, particularly where the depth of the worktop is 0.6 m. Where the depth is 0.5 m, outlets over worktops may be more easily reached. In kitchens to be used by elderly or ambulant disabled people, the preferred height for socket outlets over worktops is approximately 1.2 m above floor level.

Distribution boards Fuses, circuit breakers and isolating switches should be placed in accessible positions. For ambulant disabled people, fuses etc ought not to be higher than 1.5 m above floor level. This minimum is suitable for the remainder of the population.

Wiring systems Systems should be in accordance with the requirements of the Regulations of the Institution of Electrical Engineers.

Circuit breakers Circuits protected by a time delay tripping mechanism are suggested. When a fault has been corrected, current is restored by simply turning on the switch controlling the affected circuit. Residual current devices (RCDs) should be provided in a suitable position for garden electrical appliances; this is effectively protection by RCD for all ground floor power circuits.

Pre-payment meters Pre-payment meters, where installed, should be easily accessible. Coin slots should not be higher than 1.4 m above floor level, and not lower than 0.8 m.

Lighting equipment Some people may prefer lampholders on wall brackets in accessible positions to pendants. Many elderly people may be unable to reach pendant fittings to replace faulty bulbs. This factor is less important in family housing than in single or two-person housing. The use of energy- saving compact fluorescent lighting (with appropriate sockets/fixings) can save considerable amounts of electricity.

Lighting requirements Some people, particularly those who are elderly, require good artificial lighting conditions. Since elderly people with restricted mobility may not easily be able to take their work to the light, a better overall provision may be desirable.

BRE housing design handbook 209 _ -


Illumination levels The following levels of general illumination, based on the recommendations of the Illuminating Engineering Society, are suggested:

Entrance halls, passageways 110 lux Staircases 160 lux Kitchens 215 lux Bathrooms 110 lux Bedrooms 110 lux

Supplementary lighting should be provided at local areas where background lighting does not give adequate illumination levels. The following local illumination levels are suggested:

Sitting room, for sewing and darning 750 lux Kitchen, at preparation centre and over sink and cooker 325 lux Bathroom, over mirror 325 lux Bedroom, at bedhead 160 lux

Dimmer switches are recommended. These allow the user to choose lighting levels suitable for the task in hand.

Alarm call systems Alarm call systems are available for elderly people in housing, whether in private or sheltered housing under the supervision of a warden. These systems are generally linked to a central control through the telephone network. Some local authorities and private companies charge for this facility. Alarm call controls should be installed in each bedroom, bathroom, WC and sitting area.

Fire and smoke alarms These should be installed on each floor of all dwellings, following the manufacturers’ instructions.

Controls In bathrooms, controls must be pull cord, or push button on a suspended and insulated fitting.

Suspended fittings in bathrooms should be coloured, or distinguishable in some other way from electric light pull switches.

Television and radio reception Provision for connecting to aerials or to cable supply will normally be required for all dwellings (eg permanently installed screened cable to at least three points in the living areas).

Telephone Consideration should be given to installing permanently wired standard jack sockets in entrance hall, living room, and main bedroom.


Gas supply

Gas supply It is suggested that all new dwellings within suitable distances of a mains gas supply be carcassed for gas distribution. The installation will be governed by the Gas Safety (Installation and Use) Regulations.

Provision should be made to supply for:

1 Cooker 2 Refrigerator 3 Central heating appliance 4 Occasional heating appliance in main living room

BR E housing design handbook ,211 - . - - - -

Chapter 15

Circulation, living rooms and bedrooms


Introduction When planning a room, designers must first define:

0 The activities likely to take place in it

0 The furniture and equipment necessary for these activities

0 Aspect and prospect

0 Communication with other parts of the home

0 Occupiers’ lifestyle

0 The method of heating

0 Other rooms intended for the dwelling

This will help the designer to define minimum dimensions for particular activities and to create spaces that meet these needs. Minimum room sizes are not given; instead dimensions are given for activities carried out in particular spaces.

This chapter contains information on:

1 The activities most likely to occur within the space defined 2 The equipment most likely to be needed to perform these

3 The spaces considered necessary to perform the activities when activities adequately

using the equipment provided

Allowance is made for the physical limitations of the elderly. The needs of people in wheelchairs must be examined separately and met on an individual basis. Simple measures can be adopted to improve access for all. See British Standard BS 5619.

Space for activities Related activities The designer of a home should be aware of the main activities for which different spaces or rooms in the home are likely to be used: these can usefully be divided into ‘primary’ and ‘occasional’ categories, although they will sometimes overlap.

Primary activities in the living room (eg watching television or listening to music) can involve several members of the family and visiting friends, which tends to make the living room a ‘noisy area’. The average time spent in viewing television is over three hours per person per day. People often take their meals while watching television.

Many occasional activities are incompatible with primary activities, so make sure that a quiet space is available for ‘quiet’ activities such as study


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storage

216

++gstokge ++ Living area )

or homework when ‘noisy’ activities are taking place in the living room. If a separate dining room is not available, the bedroom space may be used. This will have design implications for how the bedrooms, the dining room and the living room are heated, what equipment is provided in each room and how it is arranged within the available space. If spaces can be used for a number of different activities the rooms will be better used, allowing a wider choice of activities for the members of the household at any one time.

Activities can also be ‘tidy’ or ‘untidy’. Most activities create some untidiness, especially those involving the preparation of meals and caring for children. If the dining space is separate from the living room, untidy activities can be concentrated in one, leaving the other available for other uses. Combining the dining area with the kitchen allows an adult working in the kitchen area to keep a watchful eye on children playing in the dining space.

South

Figure 147


- -

Space for activities

Time and place of activities

The younger family: parents and three children: a .AY of school age (7) and girls of 3 and 1

0700 In the early morning rush, instant hot water and warmth are needed.

0710 Breakfast has to be served quickly, the school child got ready and the other children looked after as they wake up.

0830 One parent and the school child leave. The other parent feeds the other children and hindherself. A place where food can be eaten near the work area is useful.

0930 The parent puts the baby out in the pram and the toddler plays outside. The toddler wanders in and out of the house. Parent needs to be able to see the children easily while working.

1130 Coming back from shopping loaded up, parent needs somewhere to put the push-chair and the shopping and enough room to take off the children’s outdoor clothes, and somewhere convenient to put them.

1200 When the children play indoors parent needs to be able to see them from the kitchen. If the children play in the kitchen they should not be able to harm themselves (with kitchen equipment) or get in the way of the parent.

Figure 148 Family activities in the morning

BRE hoiising design handbook 217


218

1230

1430

1530

1700

1800

1830

1900

When the family comes home to lunch on week days they have to wash and eat quickly. The dining space should be conveniently reached from the food preparation area.

The baby needs a quiet place to sleep. The toddler needs a place to play with toys, which does not interfere with other household activities.

Space in the tidy area of the house is needed for adult visitors, while the children of both families play within sight but not too close.

The children and the rest of the family watch television.

The family eat their evening meal from a low table while watching television.

Some people sit in other rooms. The children are put in a quiet room before going to bed.

h

Hobbies generating noise may take place, with implications for sleeping children.

Figure 149a Family activities in the afternoon and evening



2000 Visitors are entertained while a child may wish to watch his or her favourite television programme.

2200 Snacks are prepared for visitors while conversation continues.

2330 The parents need to sleep near their young children, so that they can attend to them easily.

0300 The household sleeps. If necessary, one parent will attend to the intermittent needs of the young children.

h

Figure 149b (continued) Family activities in the afternoon and evening



220

The older family: parents (mother working part-time) and boy aged 23, girl 20, boy 14

0700

0730

0830

1630

1830

2000

With four workers and a secondary school child wanting to wash before they leave home, a second WC and wash basin are needed.

There is a crush in and around the kitchen. Sandwiches are being cut, lunches packed and breakfasts eaten, before the family members collect their things and leave the house.

Deliveries (bread, milk, parcels, etc) and calls from meter readers are normally made at this time.

When the first member of the family amves home from work, the house may need warming and food preparation begun.

The evening meal may be the only time of the day when the family sit down together. They may like to eat away from the kitchen area, in particular gathered around the television.

In a family where most members are adult, several individual activities may take place in an evening at home, some of which need separate spaces.

Figure 150a The older family - morning to early evening


L


2100 The family will sometimes split up into groups during an evening and individuals may entertain their own friends separately. Room and privacy are needed for more than one group.

2230 Before going to bed, people at work often have to get things ready for the morning and meantime perhaps have a snack. Room is needed for several people to do their chores at once.

n n

2350 Separate bedrooms are needed by each individual when reaching adolescence, but they do not need to be near the parents.

Figure 150b The older family - late evening



222

Mobility standards for ambulant disabled people There is a growing need for some housing to be designed to what has become known as ‘mobility standards’. With six million disabled people in the country, the aim should be to design all dwellings to such standards. These standards are designed to meet the needs of ambulant disabled people who can move about within their own home without needing a wheelchair but perhaps making use of a walking aid such as a frame, crutch or stick. An ambulant disabled person may need to use a wheelchair when going some distance outside the home, however, so it is important that the entrance space provides easy access for the wheelchair user as well as enough space to store the wheelchair when it is not being used.

Just over 15% of the total population is aged 65 or older compared with less than 5% in 1901, and the ‘over-75’ figure is likely to double by the end of this century. Many over-75s will need housing to mobility standards, which will allow them to live in their own homes for longer.

There is a strong case for designing to mobility standards wherever possible since if all dwellings are designed to similar standards, ambulant disabled people can visit friends who live elsewhere.

The primary need for mobility standards in housing is in dwellings for small households. It is possible to incorporate these standards in ground- floor flats, flats with lift access, and single-storey houses, but more difficult in houses with two storeys or more.

The main features of mobility housing standards are:

0 The entrance to the dwelling must be accessible to the wheelchair user. It must therefore have either a ramped or level approach, or a flush threshold, or both. Weathering problems are such that a 15 mm high threshold may be considered an acceptable compromise. Steps are acceptable for ambulant disabled people, if they do not exceed 150 mm rise and 280 mm going.

Ambulant disabled people who may need to use a walking aid should be able to move easily through the internal spaces. Entrances and principal rooms (living room, dining room, kitchen and a t least one bedroom) should have 900 mm doorsets and circulation spaces serving these rooms should be at least 800 mm wide. Note that BS 5619 gives a clear space criterion of 750 mm.

0 There should be a shower or bath with shower fittings, a basin and a WC and at least one bedroom at the same level as the entrance - usually the ground floor.

Where flats are accessible by lift, the‘ internal lift dimensions must be at least 1400 mm deep x 1100 mm wide; in practice this will mean a depth of approximately 1500 mm. The door must give a clear 750 mm wide opening. The control panel should be within the range 900-1100 mm above floor level.


--

Mobilty standards for ambulant disabled people

Desirable design features Doors and windows 0 900 mm doorsets to bathrooms, WC compartments, bedrooms and

0 Doors hung to facilitate wheelchair manoeuvre

0 Door and window ironmongery which is convenient to manipulate

0 No threshold sills to internal doorsets

0 Windows placed so that a seated person can see out; no window

other rooms at entrance level

transoms at eye level of a seated person

Figure 151 (measurements in mm)

Walls and floors 0 Partition walls to bathroom and WC compartment which allow support

rails to be fixed alongside WC and bath

0 Non-slip flooring materials are important and carpeting is preferred for areas other than kitchen and bathroom, and may be justified in these areas too.

Electrical and heating services Generous provision of socket outlets

Alignment of light switches and socket outlets with door handles

0 Heater controls and coin-in-slot meters placed where they can comfortably be reached by a disabled person


Circulation, living rooms and bedroonzs

Kitchen 0 Fitments arranged to permit economical and efficient use

0 Equipment specified so that height of work surfaces can be adapted to suit particular users. Where worktops are fixed, the preferred height is 900 mm in general-purpose housing and 850 mm in housing for the frail elderly

0 A swivel tap at the sink

Bathrooms and WCs 0 A platform at head end of bath so that a disabled person can transfer in

a seated position. If this is not practicable the use of a portable bath bench may be assumed. Preferred height for the bath rim is 450 mm

0 Screw-down taps which can be replaced by lever taps if necessary

Vehicles 0 Garage or car port within the dwelling curtilage, with undercover access

to the dwelling entrance. A garage need not be made wider for use by a disabled person

Garden paths 0 In-situ paths not less than 900 mm wide although they could usefully be

1000 mm wide

Housing standards for disabled people confined to wheelchairs

.

Mobility housing standards are not a substitute for the specialist standards in housing which disabled people confined to wheelchairs require. Wheelchair standards entail many more design features than are provided in mobility standards to meet the individual needs of the more severely disabled person. The designer must be familiar with the physical problems and limitations of disabled people and design to meet their needs. This design guide concentrates on mobility standards for ambulant disabled people, and does not cover the requirements of those confined to wheelchairs.

There are a number of sources of information on designing for those confined to wheelchairs, such as BS 5619.


- _I

Furniture and equipment sizes

- Figure 1Sb Uprig5t piano, haby granii piano (rheasurerndmts in rnn )

-

B R E housing design handbook 225


~~ ~ ~

Figure l k a Playien, card {able and #ode1 railbay (meafurement! in mm) I 1

f ' 1525 A ) I Figure 1 3b Tab1 : tennis tables (measurement' in mm) 1 -

I I , I

I I I I I I I Figure l$3c Dinidg table fdr four, diding table Ior six (m&asuremebts in mmj 1

Figure l!jM Dini ig chair a Id sideboard (meas irements n mm) -

I , I

Troll y, stool a d high c air (meas rements


Furniture and equipment sizes

BRE housing design handbook 227 ~ --


Circulation: eating and sitting areas

+- soo-* 500 ;I 900 x 5oCst400-1 -


- .-

Circulation: sitting areas

Circu lation: sitting areas T1 t

I 3500 r e 56a Ta!

c ib VOOI

i n

I L

600 :: 850 n 18Eo-4 U

ng and rzading (measurements in mm)

J I

i

I

U -WO -If-850. 185.0 : 450$

ig ad televisioq (measuremer ts in Cm) I




-. -

Circulation: living areas

Circulation: living areas

t l l I I I . I

t l l I I I I

k g w e Betwlen a m c {air and c~

- Fig re lf8d etw:en s'des of a

T 1 I

all (mea urement in mm) - t l I -

ree table (measurements in rnm)

ling tab1 or sideb ard I l l

(m asu eme ts i mm

BRE housing design handbook - ~ ._ 23 1


Circulation: bedrooms


Check-list

Check-lis t Privacy and orientation 1 Does the plan itself give reasonable privacy:

(a) to its living rooms and bedrooms from people calling or passing by? (b) to its private garden from overlooking from other houses? (c) to the gardens and living rooms of other houses?

Entrance 2 What orientations are best suited to the plan to make the most of solar

gain and to minimise heat loss in winter?

3 Is there a reception lobby or hall to provide a buffer against callers intruding on the privacy of the living areas, and to minimise heat loss: (a) which is large enough to receive visitors and to allow a pram and

(b) with space for hanging outdoor clothes? furniture to be brought indoors?

A dwelling should have an entrance hall or lobby with space for hanging outdoor clothes.

4 Is there at or near an entrance: (a) provision for storing a pram without entering the living areas?

For three-person and larger dwellings served by a lift or ramp a space should be provided for a pram (1400 x 700 mm).

(b) a WC and wash-hand basin, accessible without going through the living areas?

Refuse 5 Is there shelter from the rain for callers waiting at the entrance?

6 Is there a covered route from the house to: (a) the garage? (b) the refuse store? (c) the fuel store?

7 Is the refuse store: (a) accessible to the refuse collector without his entering the house, its

(b) inconspicuous from the main entrance? store or its garage?

Meters 8 Can meters be read:

(a) from outside the house? (b) without entering the living areas?

9 If prepayment meters are fitted, is there convenient access to them from inside the house?

BRE housing design handbook 233 -.


Circulation 10 Is there a convenient route for the .push chair and for children through

the house to the garden, without entering the main living area?

11 Can members of the household get from the entrance to their bedrooms without disturbing: (a) any living area? (b) at least the main living area?

12 Can visitors get from the main entrance to the main living area without entering: (a) the kitchen? (b) the dining area?

13 Can members of the household get from bedrooms to the bathroom and a WC without: (a) entering any other room? (b) crossing the entrance hall? (c) going up or down stairs to another floor?

14 Are the circulation spaces: (a) adequate in size for larger items of furniture to be moved about the

(b) suitable for other purposes, eg cupboards, telephone? house?

Living areas 15 Is the kitchen situated where:

main living area?

that children’s play can be supervised, etc?

making it necessary for occupants to go through the main living area?

(a) it has direct access to the dining area and reasonable access to the

(b) it allows a view of, and close access to, the private open space so

(c) the kitchen has convenient access to the refuse store without

Note that in very small dwellings, occupants can prefer open plan for the feeling of spaciousness it provides.

16 Do the living areas have: (a) a view of the garden and easy access to it? (b) privacy from callers approaching the main entrance?

17 Is the general storage provision: (a) conveniently distributed, eg so that bicycles and gardening tools do

(b) likely to be free from damp - for storing the vacuum cleaner, not have to be taken through the house?

trunks etc?

18 Is the main living space large enough to accommodate the necessary furniture: (a) for the whole family and visitors?

The most likely items include: two or three easy chairs and sofas, a television, small tables, a reasonable number of other possessions, such as: video recorder, compact disc, record and tape players, radio, bookcase.

(b) to provide for alternative furniture arrangements?

234 RRE housing design handbook

Check - I is t

19 Can the main living space be shut off from the rest of the house?

20 In houses for four people or more: (a) is there a separate second living space (dining room, dining hall,

(b) can both living spaces be thrown into one for special occasions?

(c) are they well separated on plan to contribute to sound insulation?

kitchen with dining area, or study)?

or alternatively

Dining area 21 Is the main dining area large enough for the whole family and

occasional visitors?

22 If the dining area is separate from the main living space is it large enough to accommodate a sideboard and an easy chair as well as the dining table and chairs?

23 Can the working area of the kitchen be screened from view from the main dining space?

Bedrooms 24 Is there space in each bedroom to:

The occupants will have certain requirements which are likely to include:

In single bedrooms

(a) accommodate the required furniture?

Bed or divan (2000 x 900 mm) Bedside table

0 Chest of drawers A wardrobe or space for cupboard to be built-in

0 Desk

In the main bedroom 0 A double bed (2000 x 1500 mm)

or, where possible, 0 Two single beds (2000 x 900 mm each)

Bedside tables Chest of drawers

0 Double wardrobe or space for built-in cupboard Small dressing table

Note: Spaces for wardrobes, or space or cupboards to be built in later should allow 600 mm run of hanging space per person with not less than 550 mm internally.

(b) allow for realistic alternative arrangements?

25 In addition to the furniture required above is there: (a) space for a cot to be put occasionally in the main bedroom of

(b) space for a desk or dressing table in single bedrooms? houses for three people and above?


.~ -


26 When the house is not fully occupied or when the children are young and sharing bedrooms: (a) can at least one of the unoccupied bedrooms be used to enlarge the

living areas or another bedroom by using folding doors or a demountable partition?

(b) can two of the single bedrooms be used, by the same means, as a double room?

Note that the demountable partitions should be specially designed for effective sound insulation.

27 Does the plan contribute to the sound insulation between the bedrooms and between bedrooms and the living areas?


Chapter 16

Kitchens

Kitchens

Key issues Kitchen as a focal point In most households the kitchen is far more than a workplace; it is the focal point for much social activity - casual meals, children’s play, the pursuit of hobbies, informal entertaining. The kitchen needs to be designed as a family room not just as a workplace.

Private garden Figure 161

Meal preparation Although meal preparation and clearing up afterwards is rarely carried out systematically, several distinct groups of activities can be identified and arranged to form a sequence.

The fitments and appliances needed for these activities can be grouped in three main categories:

1 Storage and preparation of food 2 Cooking and serving 3 Waste disposal and washing up

I . 7

\ ,

Figure 162

ERE housing design handbook I PREVIOUS PAGE IS BUNK I

Kitchens

Diagramatic elevation of fittings

Diagramatic plan of fittings

Activities relating to fittings

The zones for activities may overlap

Figure 163 Eating may be zoned away from the kitchen in a separate dining area

Activity zones Activities in the kitchen, eg preparation, cooking and serving of meals, disposal of waste, washing up and storage of crockery, utensils and cutlery, will inevitably overlap. Someone cooking a meal will frequently double back, preparing one thing while another is cooking, alternately washing utensils and mixing ingredients and so on. The kitchen will need:

Cooking facilities

Sink draining surfaces

0 Work surfaces for food preparation

0 Storage space for food, crockery, cutlery and utensils

0 Serving facilities

Sometimes areas can be used for more than one activity; eg the sink, the draining and work surfaces be used for food preparation as well as washing up.

I -

*& \


- _ _

Key issues

Dimensions The terms used here for length, width. height and depth used in this book are defined in British Standards:

Length 0 One of two horizontal dimensions. When applied to an item of fixtures,

furniture or equipment, this is normally the dimensions from left to right, when the item is viewed from the operating side.

~

~~

i ' - .1.

-L 1.

Width 0 One of two horizontal dimensions. When applied to an item of fixtures,

furniture or equipment, this is normally the dimensions from front to back, when the item is viewed from its operational side. Figure 164

Height 0 The vertical dimension above a horizontal reference datum. Unless

otherwise stated this datum is normally the lower plane of the basic space.

Dimensional co-ordination Following the recommendations of BS 6750:1986 component and space sizes are shown in multiples of 100 mm. Heights, related to ergonomic requirements, are shown in multiples of n x 50 mm. The range of fitment sizes is based on currently available ergonomic and anthropometric research. Appliance sizes are based on the recommendations in BS 11953972.

Equipment and fittings These can be grouped into four categories:

1 The sink unit with wall cupboards above for crockery, etc, and base units below with space for dishwasher, etc.

2 The work top unit with base cupboards, drawers and wall unit above.

3 The cooker, including the hot plates or hob plus grill and oven, with a base cupboard for saucepans, a wall cupboard with an extract provided by a hood above the hot plates or hob.

equipment and refrigerator and space for a freezer, separate high level oven, food cupboard and other tall unit cupboards.

4 Storage cupboards in tall units, including a cupboard for cleaning

The number and size of the fittings and equipment will vary according to the number of people (bed spaces) in the household.


Kitchens

Section T wo 900

I T T min

& 1300c

850b I 11

12008 1000a WO a 500 a

T T

Base units and worktops

Wall units

Tall units

Sink units

Figure 165 Appliance housing units have the same co-ordinating dimensions except that there is no second preferred dimension for depth (measurements in mm)

Key to dimensions shown

a Dimensions given are ranges of commonly available sizes rather than the usual ‘large’, ‘medium‘ and ‘small’ sizes

b Second preference

c Clear height to under side of wall unit. If a zone is required for lighting it shall be included in the wall unit space


-.

Key issues

The worktop The worktop between the cooker and the sink is the most commonly used place in the kitchen. It must not be too short and any extra wall space should be used to extend it. The worktop should also have enough space for electrical appliances, such as mixer, toaster and coffee percolator. In dwellings designed for one or two people, the worktop should be at least 0.8 m long.

In kitchens for 3-5 people the worktop should be at least 1 m long, preferably longer, and in kitchens for more than 5 people, or where several people may work at the same time, 1.5 m.

The table below shows the minimum size of fittings necessary for three sizes of household (1-3 people, 3-5 people and 5 or more people).

Worktops are needed on both sides of the sink and cooker. The sequence of worktop/cooker/worktop/sink/worktop should be continuous. The depth of all kitchen fittings (except wall units) is standardised at 600 mm.

I Bl Sink units

Worktops

Cooker and pan cupboard

Total frontage of worktops

I

Tall units

Total frontage of tall cupboards

I ~ - " - No of people '

1-2 3-5 5t

1.50 1.50 1.50

0.80 1.00 1.50 ' I '

1.00 1.20 1.80

3.30. 3.70 *4.80

0.60 0.60 0.60

> I *

' 0.50 0.60 0.60

0.00 0.60 0.60% , i

1.10 1.80 1.80 '

4.40 ' 5.50 6.60 . " '

, f

- - ___CL__ I -_ Figure 166 Width of equipment, in mm

Space below the worktop There should be at least one drawer unit no less than 500 mm under the worktop. The depth of drawers is often not fully exploited, especially when they are used for cutlery. Drawers should therefore have different depths with shallow drawers above and deeper ones below.

Drawers should be easily accessible and not concealed by doors. There should also be space under the worktop for serving trays and oven trays. An adjustable pull-out board provides comfortable knee-room when working sitting down. It should be at least 600 mm wide at a working height of 630 to 660 mm. It should not be placed above drawers.

When a worktop is arranged in a corner, one frontage should be at least 800 mm.



243

Kitchens

Heights of worktops and sinks Research has shown that no single level provides the optimum height for all users. A worktop which is adjustable between 850 mm and 1050 mm high at intervals of about 50 mm is a possible long-term solution.

For static levels, a height of 900 mm for worktops and sinks with the bowl depth of 175 mm has been adopted by BS 6750.

Widths of base cupboards and wall cupboards 0 Base cupboards

600 mm front-to-back is recommended for storing and housing built-in appliances and their ancillary equipment. The danger of bumping into protruding edges is avoided when the fronts of fitments are in line with appliances.

A width of 300 mm is recommended for wall units as being suitable for storing large plates. If provision has been made elsewhere for the larger pieces of crockery, wall cupboards 200 mm wide are equally suitable, although over 600 mm wide base units the optimum usable shelf height will be lowered.

A standard 300 mm deep wall cupboard can be installed at a height above a 600 mm deep base unit which is safe yet affords a reasonable amount of accessible storage. If the base cupboard is less than 600 mm deep the wall cupboard may have to be shallower or set higher up, so that the users do not bump their heads on its leading edge. A height of 400 to 450 mm between worktop and wall cupboard meets most requirements.

0 Wall cupboards

Sliding doors Sliding doors can only be effectively used on cupboards longer than about 800 mm. They are safer than hinged doors for wall cabinets, although hinged doors are generally preferred by users because they allow the whole cupboard to be opened up at once and because they can improve storage accessibility by supporting racks and shelves. They are also not likely to jam.

Fitments with hinged doors should be carefully placed so that open doors do not clash or obstruct circulation. People are less likely to bump their heads if fully open wall cupboard doors do not overlap the counter by more than 100 mm.

Equipment: food storage Foods divide into four categories for storage purposes:

0 Foods which can be kept at more than 12°C with low humidity

0 Foods requiring a temperature of 612°C

0 Foods requiring a temperature of 2OC-6"C with relatively high humidity

0 Foods requiring freezing

Foods which can be kept at more than 12°C with low humidity High humidity can cause problems with certain foods, eg tinned goods, groceries, biscuits, dried fruit, flour and sugar. The temperature at which


Equipment

they are stored is far less important. Such foods can best be stored in a cupboard immediately above a refrigerator or in one through which a hot water pipe passes so that the atmosphere is kept dry.

Foods requiring a temperature of 6-12'C The ventilated food cupboard probably provides better storage for foods such as fresh vegetables and fruit than a refrigerator. It can also provide storage for meat and dairy produce when there is no refrigerator. However, studies have shown that the temperature in cupboards ventilated to the outside air is rarely much below that of the kitchen itself. The ventilated food cupboard is no longer a requirement of Building Regulations.

A cupboard, whether ventilated or cooled or both, used for cool food storage should therefore be well insulated and have a self-closing door. It is much more convenient to use if it is fitted internally like a refrigerator; ie with easily cleanable surfaces, adjustable shelves and vegetable baskets.

External air inlets, if provided, should be shaded from direct sunlight at all times of the day. For a family of four, a 500 mm run of base unit will usually be adequate.

The type of interior fitting which is standard in refrigerators can be used in cupboards. It can provide:

(a) Sub-divisions which keep the cupboard tidy and make individual

(b) Adjustable shelves and trays

(c) Surfaces and components which are easy to clean

(d) Insulation, when required

items easier to find Figure 168

Foods requiring a temperature of 2"C4"C with relatively high humidity The conventional refrigerator provides storage for this category of food. It will be needed only for milk, dairy products, meat and a few salad vegetables if an efficient cool cupboard is provided.

Eggs, fats and cheese can be more readily used direct from storage when kept at 6-12"C, although a lower temperature is preferable for reserve supplies.

Since the refrigerator usually has to include all the foods which need cool conditions, there is a demand for large ones needing a 600 mm x 600 mm space at least 1500 mm high; as standards rise, this space may be used for separate cold and cool cupboards above each other. 'Larder fridges' can provide more storage space as they contain no freezing compartment and may be housed under worktops in the place of a base unit.

Food requiring freezing Ready-frozen foods require the following temperatures:

* -6 to -12°C short-term storage; ** -12 to -18°C medium-term storage; *** below -18'C long-term storage.

The freezing compartment in conventional refrigerators is usually


‘.

Kitchens

intended for ready-frozen foods only. To freeze fresh foods, temperatures must be below -12°C. Two types of freezer are currently available:

(a) The chest, horizontal, top-opening freezer This takes up a great deal of floor space and is preferably kept in a utility room, cellar or garage. It uses less power and takes in less heat when opened than the upright front-opening type.

This gives easy access to its contents, and can be more easily fitted into a kitchen than the chest, horizontal, top-opening freezer.

(b) The upright front-opening freezer

People who use a freezer mainly for short-term storage may prefer an upright freezer because it can be more conveniently located, despite being somewhat more expensive to run, It is possible to use a combined fridge/freezer by keeping the freezer compartment separate from the refrigerator section and stacking them as a tall unit.

Refrigerators A full-height space should be allowed for the taller refrigerator at the end of a row of fitments. In this position it can conveniently stack with a freezer as suggested earlier. A plan area of 600 mm square will accommodate most appliances sized according to the recommendations of British Standard 11951972.

Equipment: cleaning materials A cleaning cupboard of at least 500 mm x 600 mm x 1500 mm tall should be provided for the larger equipment, such as brooms, vacuum cleaners and an ironing board. This cupboard and other cleaning storage space does not have to be housed in the kitchen. It may be most convenient to store cleaning equipment in several places. Equipment and materials for ‘wet’ cleaning (eg mops and buckets) are usually kept near the sink but this may use space which is badly needed for kitchen equipment.

246

Figure 169


Equipment

Equipment: sinks

The main uses of the sink are for: Pre-soaking dishes Washing up

0 Rinsing dishes after washing 0 Pouring waste water away

0 Getting rid of food scraps. (Some sink units are now made with a small

Cleaning vegetables etc Filling saucepans and buckets

0 Hand-washing between cooking operations 0 Clothes-washing and soaking if provision has not been made elsewhere.

third bowl fitted with disposal unit for waste water and scraps)

Size of single sinks A single sink should be at least 500 mm x 350 mm x 175-200 mm deep to take an oven shelf, the largest object commonly washed there. If the depth is increased to about 250 mm it will also be suitable for washing clothes and household linens.

Difficulties with single sinks Difficulties can often arise, even with a large single sink:

0 Double handling is frequently necessary, as when dirty dishes are put to soak immediately after use and then have to be taken out and re-stacked before washing-up can begin

0 The sink can be used only for one activity at a time

A plastics bowl is frequently used with a single sink. There are many reasons given for this practice which is essentially aimed at overcoming the short-comings of a single sink. The plastics bowl is an inadequate substitute for the double sink. On the other hand, bowls are often used in single sinks to reduce the amount of hot water consumed when only a few items are to be washed, or to protect metal surfaces from cutlery.

Double sinks With a double sink, two activities can be carried out at the same time, giving the user much greater scope in organising the work. In the UK, double sinks are still not in universal use though their many advantages are now more generally recognised.

Sizes of double sinks The type of double sink most usually found in this country has two equal sinks about 400 mm x 400 mm, but a more useful combination might be:

0 One large sink (about 500 mm x 350 mm; 175 mm deep) big enough for cleaning oven trays and, if necessary, washing clothes and household linens

0 One small sink (about 250 mm x 350 mm; 150-175 mm deep) for rinsing

A removable rack may be provided over the rinsing sink so that dishes can be stacked on it and sprayed with hot water; in this case, the sink should be at least 400 mm x 350 mm.

dishes, washing vegetables etc


----

Kitchens

Figure 17Oc

Figure 170d

248

There should be a waste outlet large enough for a waste disposal unit to be fitted later without major alterations. Until then a basket strainer waste will trap food scraps before they clog up the pipe. This outlet should be fitted to the smaller sink if unequal sinks are being used.

A possibly inexpensive alternative to the double sink might be a single large sink about 750 mm x 350 mm x 175 mm (at least) deep with a mixer tap. Two rectangular plastics bowls could then be inserted and used as a double sink when required.

Sink installation There are several ways in which the sink(s) may be installed in a continuous run of fitments. Both double and single sinks are commonly available in three forms:

(a) Combined sink/draining board unit This is the most usual type. The draining board is integral with the sink so that water can drain away easily. Where there are draining boards on both sides there will be no flat counter for food preparation next to the sink. This problem can be solved by fitting the unridged draining board which is used in several continental countries. It is imperceptibly dished towards the sink for easy draining but flat enough to be used for food preparation.

Where a single ridged draining board is used, the direction of work will be fixed and may not suit all users.

An efficient flexible seal will be needed between the sink and adjacent worktop.

(b) Single bowl sink inserted into worktop If sinks are let-in to the worktop, the worktop can run continuously over a range of fitments, giving a constant front edge and wall junction and avoiding awkward dirt-collecting gaps. Since the worktop is generally flat, however, water will not flow naturally back into the sink.

The joint between sink and worktop needs careful detailing so that it is both completely watertight and also does not prevent water from being easily wiped back into the sink.

(c) Narrow sink/draining board unit for letting-in to worktop With this type of sink unit there is nothing to obstruct the flow from the draining board to the sink, but there should be a well sealed joint between unit and worktop. As with (b), the worktop can be continuous over several fitments.


~- -

Equipment

Equipment: dishwashers, Dishwashers

cookers and hobs

More and more people will probably install dishwashers in the future. The natural place to install one is near the sink where water supply and waste connections can be made. The waste container is generally kept near the sink too, for disposal of food scraps before loading the machine.

Front-loading machines can stand permanently in position under a worktop. A plan area of 600 mm x 600 mm will accommodate most machines sized according to the recommendations of BS 1195:Part 2.

It is more energy-efficient to use machines that draw water from the main domestic hot supply, rather than heating it in the machine; this would demand a permanent connection to the hot supply.

Cookers Most households expect to be able to cook by several different methods; eg boiling, frying, baking, grilling, microwaving etc.

If solid fuel is to be used for cooking, the stove will probably be much larger than a gas or electric one and allowance should be made at an early stage to accommodate it. A flue will also be required.

An oven, several burners or hot plates, and a grill are usually combined in a single cooker. Solid fuel ranges may omit the grill but often have more than one oven and sometimes a griddle. If possible, a place for warming plates and keeping food hot should be incorporated unless it is provided separately at a serving counter.

The combined cooker is space saving and economical but has some disadvantages:

0 Hot plates or burners are set at worktop level so the oven and plate-

0 With an eye-level grill there is some risk of fat spitting in the user’s face

With a grill position immediately below the hob unit it is awkward to

warmer can not be at a convenient working height.

and a heavy grill pan may be hard to lift at that height.

see how food is cooking without pulling the tray out.

Cooking by natural gas is more economical than cooking by electricity, and this should be taken into account especially in low-budget housing.

Eye-level ovens with separate grills can be built into 600 mm x 600 mm x 1950 mm or 2250 mm high units.

If equipment is being built-in, and extra space can be made available without reducing worktop length below the minimum, a separate oven, oven and grill or oven and plate-warmer can be provided at a convenient height, so that the user does not have to bend down to put dishes into the oven.

A separate oven is best placed at the end of a row of fitments so that the run of worktop is not interrupted. It need not be near the hob unit.

Figure 171

BRE housing design handbook 249 -

L

-

Kitchens

Figure 172a

An oven, hob unit or combined cooker sized according to the recommendations of BS 1195:Part 2 will be most commonly accommodated in an area 600 mm x 600 mm.

A few years ago, about 40% of households owned a microwave oven, and the proportion will by now almost certainly be higher. The space needed by such items on the worktop should be taken into account at the design stage.

Hob units Gas and electric hob units are available separately for letting-in to the worktop, and individual boiling rings can be arranged in the counter as required. They can, for instance, be spread out along the back of the counter where stirring may be tiring for the user but pans are safely out of reach of small children. Hoods with extract fans over the hob, of 30-59 litredsec extract capacity and ducted to the outside, are a requirement of the BREEAM criteria.

Activity spaces Distances between activity areas To avoid unnecessary walking about, the different activity zones should be placed close together. A quick way to assess the general efficiency of a kitchen is to find out how far the user has to walk between the cooker, sink unit and refrigerator. The distance is measured from centre front of these units. This ‘work triangle’ should be between 3.3 m and 6.6 m.

Separate through-circulation away from activity area As far as possible, through-circulation should be kept away from the work triangle and should never cross the route between cooker and sink, which is used more than any other in the kitchen.

Figure 172b

250

Figure 172c


Activity spaces

Circulation in the kitchen Distance between a person standing or sitting at a worktop and a table or base unit

Figure 173a (measurements in mm)

Distance between a person standing or sitting at a worktop and a wall or tall unit

Figure 173b (measurements in mm)

BRE housing design handbook 25 1 - .

~ - - -

Kitchens

Eld 900 j 900b

T I

Eld 800 7 W a

1

Ovens, cookers and dishwashers High-level ovens Key to dimensions shown a An overall width of 1000-1200 mm is needed to use both the oven and adjoining setting-

down surface.

b The same depth is required for both side- and bottom-hung doors.

Eld = for elderly person

a An overall width of 1000-1200 mm is needed to use both the oven and adjoining setting- ...................................... down surface.

i Eld 800 ......

......................... +Eld 600 -)

4Mb

............................. j TEQTa I I. . ” . ;T t W +

...........................


b A depth of 1000 mm would be adequate for ovens with side-hung doors.


Cookers Key to dimensions shown Eld = for elderly person

Dishwashers

252 B R E housing design handbook

Activity spaces

Worktops and sinks Worktops Key to dimensions shown a Height at front edge of wall unit

b Height 490 mm from front of unit when reaching to back of worktop


Re = for people with restricted mobility

Standing

Sitting

Sinks Key to dimensions shown c Using only the bowl



......................... i ...................... :.. ......................I. : +

/i 750

. . . ......................... , ...................... !

, Eld 550 , t- 450-

Re 300

L ....................... ............................ ......................... -*

ij Eld 960

j j Re 850

. :...

850 Re 850

I Eld 1460

1300 Re 85Oc


BRE housing design handbook 253 , ---

Kitchens

Shelves and cupboards High shelves and cupboards Ideally, it should be possible to adjust the kitchen fitments to the height of the individual user. In some kitchen fitments the height of the base can be adjusted by up to 50 mm. For users of wheelchairs the kitchen fitments need to be specially designed. In principle, the plan is the same as for an ordinary kitchen, but with different working and reaching heights. Usually some of the units have to be replaced by others.

............. Eld 720

loo0 Re 680

Key to dimensions shown a A height of 1650 mm should enable 95 per cent of users to reach items at the front of

the shelf.

b A height of 1400 mm should enable 95 per cent of elderly users to reach with two hands items at the back of a 300 mm deep shelf.'

Eld = for elderly person Re = for people with restricted mobility

Low-level cupboards Key to dimensions shown c A height of 1450 mm should enable 95 per cent of the general users to reach items at the

front of the shelf.

d A height of 1350 mm should enable 95 per cent of elderly users to reach with two hands items at the back of a 300 mm deep shelf.

..........


1450 T 1350

1 I 1 I t - - 1

600 3 Eld490 Shallow cupboards Key to dimensions shown a For the elderly a low shelf should be not less than 300 mm above the floor to allow for full

use with both hands.



.L., ,t :+.

!!q;:.

I : '5 .: I..' ... ' ._ 2

? I 3 W a -L -

! "p

. . 950

> :: ....................... b

(- 600 -) Eld 890 1OOOd

r Eld 900

1000 Re 800

Eld 1140

Re 850

........................

Deep cupboards Key to dimensions shown b Deep shelves at low level should be avoided for elderly users.

c For pullout racks the restricted depth should be 750 mm and the width 1000 mm.

d Suits pullout racks but width should be 1000 mm.



Figure 176 (measurements in mm throughout)


Activity spaces

Storage units, refrigerators, freezers Storage units Storage units include:

0 A cupboard for cleaning materials

0 A refrigerator

0 A freezer (if any)

0 A food cupboard or other tall units

............................... .T

e 1w-l Re 700


The tall unit should be 600 mm wide, anL should pre,,rably extend to the ceiling, as cleaning the top of tall cupboards which do not reach the ceiling can be difficult and potentially dangerous. When planning the kitchen the position of the tall cupboard should be given careful consideration. Tall cupboards must never be placed between the different work units, as they will block the flow of work.

Storage for hazardous substances and medicines To help prevent accidental harm due to contact with hazardous substances and medicines kept in the home, the BREEAM criteria give credit for specifying two secure cupboards, one for the storage of hazardous substances and one for the storage of medicines.

The cupboard for hazardous substances should be located under the kitchen sink and should have a lock and key. The medicine cabinet should be located out of reach of children and should have a lock and key.

Cleaning materials The cupboard for cleaning materials can be placed elsewhere in the dwelling, but is normally found in the kitchen. In family houses it should be 600 mm wide. In smaller dwellings it can be 500 mm wide.

1900 a Height at front of freezer

Height at 450 mm from front of freezer

Refrigerator The refrigerator is usually purchased by the user. A wall space of 600 mm length is necessary for this unit. There should be a worktop next to the refrigerator.

1 1

t W R e m 600


Figure 177 (measurements in mm throughout)


Kitchens

Figure 179

256

Vertical zoning of storage related to accessibility Accessiblity Accessiblity 50% 83%

Inaccessible

0 Not easily accessible

0 Accessible

I E a s i l y - accessible

Fixed Adjustable/ shelves pull-out

shelves

Figure 178

Most available guidance on this subject is more helpful to the user of the kitchen than to the designer. A kitchen designed with shelving within comfortable upper reach of the shortest person and lowest reach of the tallest would waste a considerable amount of storage. A system whose height is adjustable seems to be the most practical way of avoiding this waste. The following principles are generally employed for determining suitable storage heights:

Frequently needed articles should be placed in a zone which extends from arms outstretched at shoulder height to the tips of fingers when arms are down at attention (for the average user 700 mm-1250/1300 mm) . Lighter items can be placed in a zone extending higher to the full reach of arms and lower to the hand height associated with half trunk bending (500 mm-1800/1900 mm).

The zones above and below these should be set aside for storage of seldom-used articles.

The need to be able to hold the articles safely when placing and removing and when reaching to the back of shelves dictates a shelf location about 100 mm shorter than the comfortable heights determined by these rule-of-thumb methods.

The usefulness of a typical cupboard can be greatly increased by substituting adjustable shelving for fixed shelving.

Cupboard storage Shelves capable of 20 mm vertical adjustment give optimum stacking efficiency for crockery in wall cupboards 300 mm deep and for cooking dishes in base cupboards 600 mm deep. The combination of shallow shelves and racks on doors considerably improves accessibility to all types of cupboard. Access to deep tall cupboards can be further improved with swing-out shelving racks, which can be used at high level. Drawers on telescopic runners can help to give easy access to the back of base cupboards and the lower parts of tall cupboards, but should not be used above shoulder level.


,

Activity spaces

Dining space within the kitchen: space for meals A dining space should be allowed for each member of the household and, if possible, for visitors. Furniture can often be temporarily rearranged to make space for visitors when extra 'full size' spaces cannot be provided.

Number of

persons

Table positions Table size (mm)

3 walls I 2walls 1 wall

m

3

4 p q

,5

I 2900 3800

l8O0 I Space for passing Space for cupboards

I I

Figure 180


Kitchens

Cookers The cooker (or hob unit if there is a separate oven) should be placed where steam and fumes can be easily extracted. It should not be placed under a window because there is a risk that curtains might catch fire; it is dangerous to reach over the hob to clean or operate the window; and the window prevents installation of a ventilating hood or eye-level grill above the cooker.

It should not be placed under a wall cupboard because there is a risk of fire. If it is essential to place a wall cupboard over the hob, the cupboard should be placed above the extractor hood. It may still, however, be dangerous to reach over hot-plates or burners to use the cupboard. Nor should the cooker be placed near a door, since draughts are likely to blow gas burners out and the door could open onto someone standing at the cooker.

Sinks Need for daylight On a typical weekday an average of nearly one and a quarter hours is spent at the sink and adjacent worktops. As the tasks done there also tend to involve longer periods of continuous work than those at other zones, good natural light is particularly important. The traditional place for a sink, under a window, meets this need.

Figure 181 (measurement in mm)

Figure 182a (measurement in mm)

Figure 182b (measurement in mm)

Figure 182

Need for adequate storage nearby A window over the sink takes up wall space which could otherwise support wall cabinets and it may be difficult to provide compensatory storage for the preparatiodwash-up zone in a convenient place.

Wall cupboards are satisfactory over the sink but should not be used to store anything likely to be damaged by steam. Doors should fit as closely as possible. If a window is to be provided somewhere in the preparatiodwash-up zone, it is probably best placed over the sink.

Sink drainer and wall cupboards Position of sink and drainer Because of the long time spent at the preparatiodwash-up zone a pleasant outlook is probably more appreciated there than at other parts of the meal preparation area. If there is a limited external wall it may be better to have the outlook from the dining area.

To avoid the need for elaborate and expensive plumbing the sink should not normally be further than 2300 mm from a soil stack or gully and should also be placed so that the run of hot water supply pipe is as short as possible.

Sinks should be installed away from the corners, so that people can stand comfortably in front of them. This is particularly important at the draining side of the sink where there should be room for a second person to help with drying.

If there is a double sink, the washing sink, but not the rinsing sink, may be sited towards the corner. This is because the natural place to stand is at the centre of the double sink, not the centre of either sink.


_- . - ..- - - - -

Activity spaces

Height of wall cupboards above work tops Wall cupboards should be set as low as possible so that the maximum amount of storage is within the user’s reach, provided that:

(a) small appliances can stand on the worktop below the cupboard. A typical mixing machine needs about 350 mm.

(b) there is, in addition to (a), room for the installation of strip-lighting below the cupboard. An allowance of 100 mm should be adequate.

(c) the user can see articles at the rear of the worktop. (200 mm of the rear wall can be seen by 90% of all women when a 300 mm deep wall unit is placed 400 mm above a 900 mm high 600 mm deep worktop.)

(d) articles stored at the rear of the worktop can be retrieved without striking one’s head on the leading edge of the wall unit. (A 1300 mm wall unit height just lies outside the arc scribed by the head when a woman of average height bends over a 900 mm high 600 mm deep worktop.)

If worktop heights above 900 mm are provided, the wall cupboard will need to move up in a constant relationship so that portable appliances can still be accommodated.

The range is composed of the following types of kitchen fitments:

0 Base cupboards below worktops, or sinks, for storage and housing built-

Tall floor-to-ceiling cupboards for storage and housing built-in

Shallow wall cupboards above worktop level for storage

in appliances

appliances

The designer should consider the following points when designing or selecting fitments to provide storage and work surfaces.

0 Efficiency Space above and below worktops should be fully utilised, preferably for storage, so that materials and utensils can be kept near the place where they are first used.

0 Convenience Dimensions should be related to the user. If fitments cannot be adjusted to individual needs, sizes should be chosen to suit the majority of users.

0 Provision for appliances It should be possible to incorporate built-in and free-standing appliances into the system and to connect them to services easily.

0 Maintenance The chosen material should be easy to clean; dirt-collecting crevices should be avoided as far as possible. The junctions between units and at walls, floor and ceiling should be sealed unless specific provision is made to allow easy cleaning.

Figure 183

Figure 184 (measurement in mm)

!SO


Kitchens.

i

Figure 185

260

Worktop heights The convenience of a standard-height meal counter or table will obviously vary according to the chair or stool used but for a dining chair with a seat height of 420 mm a counter or table height of 720 mm is probably the most suitable.

Unless adjustable fitments are used, an adjustable pull-out board is desirable which can be used by shorter people in the working area to provide a stable surface where meals can be taken or lengthy tasks undertaken either sitting or standing.

To cater for as many uses and users as possible, the board should be adjustable to heights at approximately 50 mm intervals between 650 mm and 900 mm. It should be at least 400 mm long (600 mm for meals). The width, which will depend on the type of sliding system used, should be at least 450 mm.


--

Check-list

Check-lis t

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Does the kitchen have reasonable access to the dining area? There should be not more than two doors and a short length of passage between them.

Does the kitchen have a view of, and close access to, the private open space (if any) for supervising children’s play, putting washing on the line, etc?

If an outside door opens directly into the kitchen, is there: (a) adequate protection from wind and driving rain? (b) somewhere to leave outdoor coats, shoes, etc?

Does the kitchen have some view of the outside world, callers, passers-by etc?

Has orientation been considered?

Is there convenient access from the kitchen to the refuse store without going through the main living area?

Is there a convenient place indoors where small children can play within sight of the kitchen working area?

Is there a sequence of work surface/cooker/work surface/sink/work surface, unbroken by doors, passageways or tall fitments?

Is the total ‘work triangle’ distance between sink, cooker and refrigerator (or centralised food store) between 3.6 m and 6.6 m?

Is the ‘work triangle’, or at least the route between sink and cooker, free from through-circulation?

When the working area is separate from the dining area, is there space for a table or a built-in counter for casual meals?

Is there an adequate length of worktop?

Is there enough room for appliances?

IS the kitchen arranged so that work surface, appliances and storage for each activity are grouped conveniently together to form an activity zone?

15 Is enclosed storage adequate?

16 Does the storage space include at least a 400 mm run of base cabinet or equivalent (volume 0.18 m3) in which the temperature can be kept below 12°C for storing vegetables and cooling cooked foods?

17 If it is not provided elsewhere, is there a cupboard at least 500 mm x 600 mm x 1500 mm high (volume 0.5 m3) for cleaning materials, in addition to the minimum storage given in 16 above?


Kitchens

262

18

19

20

21

22

23

24

25

26

27

28

Are clearances between fitments, doors, etc, adequate?

Is there scope for future alteration and improvement?

Are all surfaces easy to clean?

Is there adequate natural and artificial light on worktop surfaces?

Are there enough electrical socket outlets for all the equipment likely to be used? (There should be at least four in the meal preparation area).

Can cooking steam and fumes be extracted near their source? Is there adequate ventilation for the room as a whole?

Are sinks, dishwashers, etc, grouped to allow an efficient water supply and drainage system?

Is the room adequately heated?

Is there space in the kitchen for some members of the family to eat occasional meals?

Do doors which open into the kitchen clear working areas and cupboard door-swings?

Are there adequate means to prevent cooking smells reaching: (a) the main dining area? (b) other parts of the house?


-, -

Chapter 17

Utility areas

Utility areas

Key issues Porch A utility area (eg a large storm porch) is recommended for energy conservation and for storing outside clothes and footwear.

/ ) Utility -$ Circulation <

Kitchen Dining area area

L

Outdoor drying space

i

Figure 186

Laundry It is normal to make provision for laundering in the kitchen or in a utility area linked to the kitchen, but the dangers of cross contamination between dirty clothes and food should be avoided. The laundering process can be ordered in a logical sequence. Washing and drying are necessarily camed out in immediate succession. Space for sorting usually needs to be provided near the washing place. The laundry area needs washing and drying equipment, storage space for washing materials and, if possible, a surface for sorting. Storage for dirty washing and airing space can be provided elsewhere.

. . ._ _ . ._ . . . . . . . . . . . . . - .. . . __.*.-..--~I..- U-- -

Figure 187

BRE housing design handbook I PREVIOUS PAGE IS BlANK I 265

-

Utility areas

I I


A single appliance space (800 or 600 mm x 600 mm) is usually provided for a washing machine under a worktop in the kitchen, and part of the kitchen storage space is used for washing materials. This is unsatisfactory for several reasons:

0 Hygiene There is a danger of cross-contamination through the handling of dirty washing during food preparation. Grease and cooking smells can be passed on to clean clothes.

Conflict with kitchen requirements This occurs when washing appliances, conveniently placed near the sink for easy water supply and waste connections, take up space which is needed for kitchen storage or appliances.

To avoid this problem, a separate area for laundry activities is recommended.

Provide where possible:

0 A separate zone (at least 1200 mm x 600 mm) for equipment, and sortingktorage of materials

0 Storage for an ironing board

0 A separate utility area for laundry

Storing and sorting Storage provision If washing is done weekly, storage will be needed at a rate of about 0.02 m3 per person per week; allowing for an-overlap this works out at roughly one tenth of a cubic metre or so for a five-person family. Many households do their washing in small batches several times a week, which allows them to treat each type of fabric separately. As loads of similar fabrics may be built up over a period of time, storage space should be not less than for a weekly wash.

For reasons of hygiene, dirty washing storage needs to be well ventilated. For sorting, a 900 mm x 600 mm surface should be adequate. Usually, this will not need to be specially provided as nearby surfaces (eg machine tops) in the 700 to 900 mm height range are just as suitable.

Storage location 0 Laundry Dirty clothes kept in the laundry space can be sorted directly into the washing machine.

0 Bathroom The bathroom is a convenient collection point for dirty washing. In many households a laundry basket is kept in the bathroom.

0 Bedroom In one- and two-person households, the bedroom may be a convenient place to keep discarded clothes and household linens, but good ventilation is essential. In large dwellings the dirty linen store should be accessible from a circulation area or a bathroom, unless there is a separate container in each bedroom, so that it is available to all members of the household.


Key issues

1

Washing Sink

A sink at least 500 mm x 350 mm x 250 mm deep is needed if the major wash is done by hand, and a second bowl or tub (which might be on wheels) is highly desirable. The size of the sink is less important when a washing machine is used.

1100

Combining an integral sink and sorting-top unit with deep storage drawers below can be economical.

0 Washing machine Some washing machines (non-automatic or semi-automatic) have attached wringers, although these are becoming less common. Non- or semi- automatic machines generally cost less than automatic ones and need less hot water for a given amount of washing.

Most non- or semi-automatic machines are not attached to the plumbing and need to be temporarily connected to water and waste services at the sink.

0 Work surfaces A work surface at least 600 mm x 600 mm is needed for setting down clothes between washing and rinsing or before drying. A surface 900 mm x 600 mm can also be used for sorting.

0 Storage Storage space of about 0.15m3 will be required for washing materials, basins etc. Where there are small children, base cupboards containing potentially harmful materials like detergents should be lockable.

0 Hand washing (small quantities) Regardless of other arrangements for laundry, it is still necessary to wash by hand some delicate fabrics and small items. A bathroom hand basin is usually adequate for this purpose, provided that there is an adjacent place to hang clothes for drip-drying.

0 Automatic machine When automatic machines are used, a sink is not essential in the laundry area so long as there is provision for light hand-washing elsewhere. Stacking an automatic tumble-drier on its washer counterpart can save space significantly.

600 I700

1000

Figure 189a

L 1000

1100


Figure 189c (measurements in mrn)

Figure 189d (measurements in mm) Figure 190


Utilitv rri-errs

1000


600

1000


600

1100 i

1000

Figure 191c (measurements in mm)

Work surface - A work surface is useful but not essential. as sorting can be done elsewhere and there is usually no need to set down clothes between various stages in the operation. A basket or trolley can be used for clothes when loading or unloading the machine.

Storage - Slightly less storage space is required for an automatic washing installation than for a non-automatic one because fewer basins and buckets are needed. A 500 mm run of wall cupboard 600 mm high (0.09 m') should usually be adequate.

A fully automatic machine requires less space than other types of installation and can be used frequently without disrupting other activities in the room.

Drying and ironing Drying There should be as short a distance as possible between washing and drying places. as wet washing is heavy.

Good ventilation and water-resistant surfaces are essential for indoor drying, which causes much condensation.

When wrung by hand. washing retains 150% of its dry weight in water; a hand wringer reduces this to 100%. A vertical spin-drier can extract up to 50% of the moisture in washing but the washing still needs further treatment for complete drying. The tumble-drier takes washing to a condition in which it is ready for ironing. Other drying systems include ventilated heated cabinets, retractable lines, collapsible racks over baths, or simply a line outside and confidence in the British climate.

The tumble-drier and heated cabinet make economical use of space. requiring about 600 mm x 600 mm for a capacity of 3 to 4 kg. Where possible they should be against outside walls to allow direct extraction of steam. Vents should be taken to the exterior of the dwelling to reduce the amounts of condensation which will form. Combined washers and tumble- driers are now becoming available.

Unless clothes-drying is done mechanically, racks or lines of up to 6 m per person per week will be needed both indoors and outside. When several lines are parallel there should be 200 mm between them to allow for efficient drying.

With a spin-drier, only about 2 m of line per person per week will be needed to allow for the final stages of drying before ironing, and lines can be closer together. Drying racks should never be placed near the cooker, and preferably not in the kitchen at all.

Even with an automatic drier, room will still be needed for drip-dry clothes. A pulley-operated rack, or a line over a bath or shower tray will often be adequate. If drip-dry clothes are dried elsewhere, in a utility room for example, a draining-tray with trapped waste will be required.


~

Drying and ironing

circulation through stored linen. and ideally the shelving should be adjustable.

Pre-ironing storage As the washing cycle is often broken between drying and ironing. two shelves 300 mm x 400 mm x 200 mm high storage may be required for damp washing awaiting ironing for a family of five. .

150

400

Ironing No space needs to be provided for ironing near the laundry area since a portable ironing board can be set up almost anywhere. Storage for the ironing board is usually provided in a tall cleaning cupboard.

Since current designs of hot water cylinder give off very little waste heat. it may be necessary to install a heater in airing cupboards.

300 1350


I 1 850

150

400

850


300 I600

600

1000


- _

269 ~ -7

C heck-lis t Are appliance spaces, work surfaces and storage facilities adequate fdr each stage in the laundering process?

Recommendations are: 0 Dirty washing storage: 0.02 m3 per person per week

Sorting: work surface 900 mm x 600 mm Washing by hand: Sink 500 mm x 350 mm x 250 mm deep Work surface 600 mm x 600 mm Storage for materials 0.135 m3

space* 1400 mm x 600 mm x 900 mm high Work surface 600 mm x 600 mm Storage for materials 0.135 m3

0 Washing and drying by automatic machines: Appliance space* for adjacent washers and driers 1200 mm x 600 mm x 900 mm high; for stacked washers and driers 600 mm x 600 mm x 2300 mm high Work surface not essential Storage for materials 0.09 m3

6 m per person 200 mm apart

Washing and drying by non or semi-automatic machine: Appliance

0 Drying if clothes are wrung mechanically or by hand racks or lines:

0 Spin-dried clothes: 2 m per person

0 Drip-drying: no definite recommendation; as much space as possible

0 Pre-iron storage: 0.5 m3 for a five-person household 0 Ironing: Standing space to use the iron 1000 mm x 1800 mm

(perhaps above a bath or shower space)

Seated 1250 mm x 1800 mm Rotary iron 1300 mm x 1200 mm Storage for ironing board 600 mm x 300 mm (min) x 1500 mm high

0 Airing: 0.02 m3 per person per week 0 Linen storage: 0.6 m3 for 4 people and above 0.4 m3 for one to three

*A space 1400 mm x 600 mm x (at least) 900 mm high will in most cases be adequate for any combination of machines. Does the laundry area have direct access to drying places out of doors (if any)? Are floors strong enough to withstand the weight and vibration of laundry appliances? (A typical automatic washing machine weighs 150 kg.) Are adequate services available for all stages in the process? 0 Electrical socket outlets conveniently placed for any appliance

0 Wherever possible water supply and waste connections should be

people

which may be installed.

available so that washing and drying machines can be easily attached to the plumbing.

Can washing and drying machines be adequately ventilated? Is it convenient to supervise semi-automatic machines while carrying on other domestic activities?


Chapter 18

Bathrooms

Bathrooms

Introduction Bathroom activities In the late 1960s, a Ministry of Housing and Local Government internal survey (based on interviews with nearly 1000 householders) found that just over 50% of single-person households and 85% of households with two or more people preferred the WC to be separate from the bathroom if only one WC was to be provided. This percentage reduced if this resulted in a smaller bathroom.

Bathroom size should be determined by the need to position appliances for comfortable use and to provide space for extra items. Planning enough space is particularly important in bathrooms containing a bath and basin but with a separate WC. There is no evidence that preferences have changed since the 1960s.

In households with young children there must be enough space for an adult to supervise the bathing and washing of children.

The position of the bathroom in the home will affect its use and the amount of washing facilities needed. Children coming indoors from play and adults returning after work or gardening tend to use the kitchen sink for washing rather more often than the basin in the bathroom, especially when the bathroom is situated away from the entrance into the house such as on another floor. This points to a need for washing facilities on the ground floor, preferably supplementary to the kitchen as part of the utility room or as a separate cloakroom. This is important when meeting the needs of a large or growing family household.

The following information on activities, equipment and user space related to bathrooms is based on the minimum activity space for using each item of equipment or appliance rather than on a fixed overall floor area for each bathroom type. Designers can then use various combinations of individual appliances and their activity spaces to make up different bathroom layouts to meet specific client needs. This will help to maintain a consistent allowance of space for the use of each appliance so that the overall bathroom floor area and shape can be determined by other requirements such as the need to provide a dressing area or to include laundry equipment which cannot be accommodated elsewhere.

Appliance sizes Equipment sizes given in this chapter are based on the nearest 100 mm of the most common sizes currently available. Appliances specified by the designer may vary in size from those shown but the dimensions of activity spaces may be considered as constants.

The bath and shower The shower is often considered more efficient than the bath because of its continuous flow of water. It also uses, on average, less water than the bath and its compactness makes it a convenient alternative where installation

BRE housing design handbook I PREVIOUS PAGE IS BLANK I 273

Bathrooms

I . I

700 700

1700 mm x 700 mm on plan Rim height: 500 mm - 600 mm range


space is limited. The popularity of the bath, particularly in family dwellings, is unlikely to diminish in the near future, however, since it is more convenient for relaxation and for washing children.

The shower A wall or partition is normally needed across the tap end of the bath for fixing a shower outlet. In some layouts this may mean that the outlet end of the bath cannot be positioned to give the greatest economy of services runs. When a shower attachment is fitted, the bath activity space should be aligned, where possible, with the tap end unless permanent shower side- screens (which prevent water spraying on to the floor) are fixed to the bath.

Side-screens on a normal-width bath would cramp the user. A wider bath is more comfortable to use and provides a better catchment area for spray.

The bidet The bidet has been included although it is not yet widely used in Britain. It may become more popular and is a convenient alternative to the bath for washing the perineal region and is a great saver of water. It may also prove useful for foot washing.

The bath Appliance dimensions British Standards size 1700 mm x 700 mm, and co-ordinating heights on n x 50 mm. Other plan sizes to be multiples of 100 mm.

The current tendency is to follow a popular preference for a lower bath rim, which for elderly and disabled people may prove easier and safer for getting in and out.

Corner baths have become popular in recent years, but since their dimensions vary considerably, special provision needs to be made at installation. The activity spaces will be identical with those given below.

Activity space 1100 mm x 700 mm clear floor space is needed with the longer dimension adjacent to one side of the bath. This allows for getting in and out of the bath, for drying, and for an adult beside the bath bathing a child. The defined area does not extend for the whole length of the bath and can be positioned at any point along it, preferably at the tap end. The area beside the bath beyond the activity space should be included within the floor area of the bathroom so that bath taps can be reached and the tub cleaned from the activity space whatever its position. The area can be occupied by a second appliance or by other items such as a stool or laundry box.

Full floor-to-ceiling height is needed over the activity space and the length of bath related to it. Beyond this area a change in ceiling plane is possible and could be convenient where, for example, a bathroom is being installed in an existing building with sloping or low ceilings.


The shower

An area 1100 mm x 900 mm is recommended for dressing and drying, and for activities not fully covered by the appliance activity space. It can also be a useful check on bathroom-plan area and shape. When the bath is combined with other appliances, however, space will usually be available within the resulting plan without need for this special provision.

The shower Appliance dimensions 800 mm x 800 mm and 900 mm x 900 mm on plan are the most common sizes. Tray height: 150 mm is considered to be a practical minimum.

These sizes apply to all types of shower, including:

0 an unenclosed but drained corner of the bathroom (as more commonly

0 basic floor trays, which can be fitted with various degrees of screening,

0 the ‘packaged’ shower unit supplied as an integral floor tray and

found abroad);

either set into or standing on the floor plane;

enclosing cabinet.

Activity space If enclosed on one or two sides: use an area on plan of 400 mm x 900 mm (or width of tray used) adjacent to one open side of the shower. This space is for access and allows for drying, partially within the shower.

If enclosed on three sides: use an area 700 mm x 900 mm. This space is for access and towelling. Full floor-to-ceiling height is needed over the shower and its activity space.

As with the bath, an area 1100 mm x 900 mm is recommended clear of the shower for dressing and as an alternative area for drying. This may overlap or include the defined activity spaces.

The washbasin Appliance dimensions 600 mm x 400 mm on plan. Front rim height: 800 mm for pedestal sets.

The 800 mm height is really a compromise for family dwellings: a height of 900 mm would be better for adults; small children have difficulty reaching 800 mm; a lower height is more convenient for washing face and hair.

Activity space Full standing-height is needed over the front half of the basin and over all its activity space. Storage and fittings above the basin should be clear of the arc described by the user when bending over the appliances.

900 700

0 0 a,

Enclosed access one side only

900 400

0 {=I] 0 a, : .- ,, . , > ’ G . .. . . . . . .

. . .,, ... 4.. ,

Unenclosed

Figure 194 (measurements in mrn)

400 700 I r------

Figure 195 (measurements in rnrn)

BRE housing design handbook 275 - -

Cloakroom basins Where a small basin intended primarily for hand-washing is installed in a cloakroom or WC compartment, the basin activity space specified for washbasins can be reduced to 800 mm x 600 mm. A 300 mm x 500 mm basin which would be suitable for WC compartments has been shown on some of the following plans. Many sizes and variations are available including types which can be set in a corner location or into the thickness of a wall. These will affect the size of the compartment required, but the activity space will always be the same in principle.

0 3

0 0 0 N-

muscular action involved in evacuation. But a lower WC could prove too low for elderly people and for standing male use (for which a urinal, though possibly unacceptable in the dwelling, would be far more appropriate). At present it seems that it would be difficult to manufacture

0 0 CO m w I Figure 1% (measurements in mm)

The bidet Appliance dimensions 700 mm x 400 mm on plan. The suggested height for dimensional co-ordination is 400 mm, corresponding to that of the WC.

Activity space A space of 800 mm wide x 600 mm deep on plan is needed, measured from the front lip of the appliance. The activity space should be considered as extending along each side of the appliance up to the full 800 mm width to provide leg room and allow space for the user, who sits facing the controls, and to make cleaning of the side and rear parts of the bowl easy.

Full standing-height is needed over the bidet and its activity space to enable the user to stand astride the bowl and to use it as a footbath.

Most bidets can be filled through the rim. Some are also fitted with an upward douche spray to which special regulations for installation apply. In general, hot and cold supplies must be drawn from a tank, not from a mains supply pipe, and the supply pipes to the bidet must not have any tee-offs to other appliances. Detailed requirements should be checked with the appropriate authority before installation.

The WC

Relationship between spaces

Activity space A space of 800 mm x 600 mm on plan, measured from the front lip of the appliance, is needed; ie the same activity space as for a bidet. The space allows for standing or seated use of the WC and for the necessary removal of clothing. As with the bidet, the space each side of the appliance should remain clear up to the 800 mm width of the activity space to allow the seated user full elbow width and to leave the side and rear parts of the bowl accessible for cleaning.

Full floor-to-ceiling height is needed over the activity space and part of the appliance to allow for standing use, but some slope of ceiling plane is possible over the appliance where, for example, it is being installed in an existing building. Any change in ceiling plane should be outside the arc formed by the user bending to clean the bowl or lift the seat and should not restrict access to a low-level cistern.

Relationship between spaces The application of appliance and activity space data It is possible to determine constant relationships between the defined activity spaces for each appliance when they are combined in a bathroom layout.

These relationships are indicated by:

(a) the dimension measured between centre-lines of adjacent appliances; or, with the bath and shower, to their outer face. (In this way the activity spaces illustrated will not be affected by different sized appliances);

(b) the maximum overlap of activity spaces (where appropriate) for each possible combination of the five bathroom appliances, in 100 mm increments.

Fixed relationships between appliances

400 700 700 400

- Figure W8a (measurements in mm)


Bathrooms

400 400 400 500

278

0 0 d

0 i?

0 0 b

0 0 d

Figure 198b (measurements in mm )

Overlap of spaces Some adjacent activity spaces can overlap, with consequent savings of space and services-runs. An overlap of activity spaces can occur:

(a) if the critical activity space dimensions of two adjacent appliances are related to different horizontal planes; (eg a basin activity space can overlap that of the WC or bidet by 200 mm without obstructing the use of either appliance; a basin or WC, when adjacent to the bath or an unenclosed shower, can overlap these appliances by 100 mm);

simultaneously (eg WC and bidet);

great inconvenience (eg two washbasins).

(b) where two people are unlikely to use two adjacent appliances

(c) where duplicated appliances could be used simultaneously without

There are some possible relationships which are not indicated in the illustrations. These will occur mainly where two appliances are located against two walls at right angles to each other, or where they face each other against two opposite walls. This allows their respective activity spaces to overlap, although the activity space of one appliance should not overlap the other appliance itself.


. ,

Layouts

1100

1300

1400

1500

1600

1800

2200

1000 1500

Layouts The matrix shows space dimensions where single appliances are used, and where two or three appliances are used in combined spaces.

As both the WC and the bidet have similar sized activity spaces they can be interchanged on the layouts shown.

Matrix of combined appliance and activity spacc for one, two and three-appliance layouts



F i i 199b

1300

1400

1500

1600

1800

2000

(measurements in mm)

1900 2100


ti 3296

2500

Layouts

2600

900

1100

1300

1400

1500

1600

F i l99c (measurements in mm)

3200


Bathrooms

C heck-lis t 1 Is the bathroom and WC provision adequate?

If the dwelling provides accommodation for up to three people, one space combining the bath, basin and WC may be adequate. In dwellings accommodating a greater number of people it may be advisable to provide a separate WC compartment with its own wash basin unless the compartment is adjacent to the bathroom. In larger dwellings it may be advisable to provide a second WC and basin in a separate compartment, perhaps as a cloakroom adjacent to the entrance to the dwelling.

2 In houses with a second WC and basin, is the compartment and its basin large enough to be used by an adult for washing, as an alternative to the bathroom?

3 Is there adequate space in the bathroom and WC compartments: (a) around the fittings? (b) to open the door and enter easily? (c) to accommodate a stool in the bathroom in addition to the

fittings?

4 Does the plan contribute to sound insulation between WC and: (a) the main entrance? (b) the living areas? (c) the bedrooms?

5 Are the windows positioned: (a) to give the best possible ventilation? (b) where they may not be overlooked by passers-by? (c) where they may be easily operated without danger to the user.

6 Does the bathroom and WC provision meet the needs of elderly and ambulant disabled people?

The WC and washbasin (a) The WC should be provided with at least one hand-hold

conveniently set at the side of the pedestal. (b) The door to the WC compartment should open outwards and be

fitted with special locks openable from the outside in case of emergency.

The bathroom (a) The bath should be flat-bottomed and of such a length that an

elderly person cannot become completely immersed (a maximum standard length of 1550 mm).

(b) There should be at least one hand-hold to assist an elderly person into or out of the bath.

(c) The door to the bathroom should open outwards and be fitted with special locks openable from the outside.

(d) The floor surface should be non-slip. The shower (a) The floor of the shower compartment should be non-slip and safe

(b) The hot water output to feed the shower must be thermostatically from hazards.


Check-list

controllable.

wall-mounted seat. Spray outlet should be adjustable to varying heights.

(c) The shower compartment should contain a secure hand-hold and

(d) The floor surface should be non-slip.

Is there space in the bathroom to accommodate the sanitary furniture and all the essential items needed by members of the household? These might include:

Bath Washbasin wc Shower (fixed in own compartment) Shower (portable attachable) Bidet Medicine cupboard Open shelving Airing cupboard Any other storage cupboard Laundry basket, box Mirror (not attached to cupboard) Chair Stool Bath mat Clothes line, rack Drying cabinet Towel rail, rack Scales Shaving point Bath soap rack Toilet paper holder Toothbrush holder

8 Are the fittings chosen for economy in the use of hot and cold water?

9 Are tap fittings easy to clean?

10 Is WC provision adequate?

0 The WC may be in the bathroom in one- and two-bedroomed

In three-bedroomed dwellings, where one WC is provided, it should

In dwellings containing more than three bedrooms, at least two WCs

0 A separate WC which does not adjoin a bathroom should contain a

dwellings, where only one WC is provided.

be in a separate compartment.

should be provided, one of which may be in the bathroom.

washbasin. It is preferable for a separate WC to contain a basin even, if it does adjoin the bathroom.

Note: The number of bedrooms is taken in the above as a rough surrogate for number in household.


Acknowledgements

Acknowledgements The following members and former members of BRE contributed to the preparation of this book.

P B Bartlett, D T I G Davies, L C Fothergill, J C Griggs, J Hall, J Harrington-Lynn, H W Harrison, G Henderson, E J Keeble, P J Littlefair, A A B Musannif, F Nowak, N A Oseland, E F O’Sullivan, R E H Read, J R Southern, C R Stableford, G M B Webber, and A W Williams.

The preparation of this book was also funded in part by the Energy Efficiency Office, now of the Department of the Environment.

Chapters 12 and 13 were prepared by Energy Conscious Design Ltd under contract to BRECSUEEO.

Thanks are due to all those in the housebuilding industry who provided comments and criticism of the drafts.

References Harrison H W. Quality in new-build housing. Building Research Establishment Information Paper IP3193. Garston, BRE, 1993.

Bonshor R B and Hamson H W. Quality in traditional housing. V o l l : an investigation into faults and their avoidance. Building Research Establishment Report. London, HMSO, 1982.

Prior J J, Raw G J and Charlesworth J L. BREEAM/New Homes. Version 3/91. An environmental assessment for new homes. Building Research Establishment Report. Garston, BRE, 1991.

Hanison H W and Keeble E J. Performance specifications for whole buildings. Building Research Establishment Report. Garston, BRE, 1983.

O’Reilly J J N. Better briefing means better buildings. Building Research Establishment Report. Garston, BRE, 1987.

Langdon F J, Buller I B and Scholes W E. Noise from neighbours and the sound insulation of party walls in houses. Journal of Sound and Vibration, 1981,79 (2) 205-228.

Oseland N A. An evaluation of space in new homes: a facet approach. MSc Dissertation. Guildford, University of Surrey, 1990.

Utley W A and Keighly E C. Community response to neighbourhood noise. Fifth International Congress on Noise as a Public Health Problem, Stockholm, 1988.

Cohen S. Cognitive processes as determinants of environmental stress. In Stress and anxiety volume 111. (Eds I Sarason and C Spielberger.) Washington DC, Hemisphere Press, 1980.


References

286

10 Oseland N A and Raw G J. Room size and adequacy of space in small homes. Building and Environment, 1 9 9 1 , s (4) 341-347.

11 Ministry of Housing and Local Government (now DOE). Homes for today & tomorrow. (Parker Morris Report). London, HMSO, 1961.

12 Britten J R. What is a satisfactory house? A report of some householders’ views. Housing Review, 1 9 7 7 , s (5).

13 Raw G J and Fox T A. Condensation, heating and ventilation in small homes. CIB proceedings Publication 121. Technical Session I of the proceedings of the International CIB W67 Symposium on Moisture and Climate in Buildings. Chapter 127. Rotterdam, CIB, 1990.

14 Simpson J and Tarrant W S. A study of lighting in the home. Lighting Research and Technology, 1983,s (1) 1-8.

15 Lowry S. Noise, space, and light. British Medical Journal, 1989,299 1439-1442.

16 Building Research Establishment. Climate and site development. Part 1: general climate of the UK. Part 2: Influence of microclimate. Part 3: Improving microclimate through design. BRE Digest 350 Parts 1 to 3. Garston, BRE, 1990.

17 Littlefair P J. Site layout planning for daylight and sunlight: a guide to good practice. Building Research Establishment Report. Garston, BRE, 1991.

18 Building Research Establishment. Sunlight availability protractor. Garston, BRE, 1989.

19 NBA Tectonics. A study of passive solar housing estate layout. ETSU Report S-1126. Harwell, Energy Technology Support Unit, 1988.

U) Clouston B and Stansfield K (Eds). Trees in towns. London, Architectural Press, 1981.

21 The Chartered Institution of Building Services Engineers. Applications manual: window design. London, CIBSE, 1987.

22 Building Research Establishment. Estimating daylight in buildings: Part 1. BRE Digest 309. Garston, BRE, 1986.

23 Building Research Establishment. Estimating daylight in buildings: Part 2. BRE Digest 309. Garston, BRE, 1986.

24 Anstey J. Rights of light and how to deal with them. Surveyors Publications. London, Royal Institute of Chartered Surveyors (RICS), 1988.

25 Ellis P. Rights to light. London, Estates Gazette, 1989.

26 Department of the Environment. Planning and noise. D O E circular 10/73. (To be replaced by a Planning Policy Guidance note in 1993.)


References

27 Department of the Environment. Calculation of road traffic noise. London, HMSO, 1988.

28 Building Research Establishment. Insulation against external noise. BRE Digest 338. Garston, BRE, 1988.

29 Department of the Environment and the Welsh Office. The Building Regulations 1991. Part E: Resistance to the passage of sound. Statutory Instrument 1991 No 2768. London, HMSO, 1991.

30 The Building Standards (Scotland) Regulations 1981. Part H: resistance to transmission of sound.

31 Building Regulations (Northern Ireland) 1990. Technical booklet G: sound. London, HMSO, 1990.

32 Building Research Establishment. Sound insulation of separating walls and floors. Part 1: walls. Part 2: floors. BRE Digests 333 and 334. Garston, BRE, 1988.

33 Fothergill L C and Savage J E. Methods for reducing impact sounds in buildings. Building Research Establishment Information Paper IP 9/88. Garston, BRE, 1988.

34 Harrington-Lynn J. Locks on doors to flats: ergonomic requirements. Building Research Establishment Information Paper IP1/92. Garston, BRE, 1992.

35 Anderson B R, Clark A J, Baldwin R and Milbank N 0. BREDEM: The BRE Domestic Energy Model. Building Research Establishment Information Paper IP16/85. Garston, BRE, 19S5.

36 Anderson B R. Energy assessment for dwellings using BREDEM worksheets. Building Research Establishment Information Paper IP13/88. Garston, BRE, 1988.

37 Building Research Establishment. Thermal insulation: avoiding risks. BRE Report. London, HMSO, 1989.

38 National House-Building Council. NHBC good practice guide. Thermal insulation and ventilation. London, NHBC, 1991.

39 National House-Building Council. Standard 6.1: External masonry walk. Amersham, NHBC, 1990.

40 British Gas. Design Guide. Central Heating: a guide to the design and operation of domestic wet central heating systems. British Gas, 1983.

41 Electricity Council. The Economy 7 boiler. EC 4497. DOM 10. London, Electricity Council, 1983.

42 Electricity Council. Installer’s guide: the electric dry core boiler. EC 4703. London, Electricity Council, 1988.

43 Electricity Council. The design of mixed storage heateddirect systems. EC 5271. DOM 8. London, Electricity Council, 1989 .

BRE housing design handbook 287 - .

-

References

44

45

46

Electricity Council. Design of Economy 7 water heating. EC 4964. DOM 9. London, Electricity Council, 1988.

Stephen R K and Uglow C E. Passive stack ventilation in dwellings. Building ReseaKch Establishment Information Paper IP21/89. Garston, BRE, 1989.

Stephen R K. Domestic mechanical ventilation: guidelines for designers and installers. Building Research Establishment Information Paper IP18/88. Garston, BRE, 1988.

British Standards Institution publications referred to in this handbook BS 416. Discharge and ventilating pipes and fittings, sand-cast or spun in

cast iron.

BS 476. Fire tests on building materials and structures. BS476:Part 22:1987. Methods for determination of the fire resistance of

non-loadbearing elements of construction.

BS 585. Wood stairs. BS 585:Part 1:1989. Specification for stairs with closed risers for domestic

use, including straight and winder flights and quarter or half landings.

BS 2871. Specification copper and copper alloys. Tubes. BS 2871:Part 1:1971. Copper tubes for water, gas and sanitation.

BS 3868:1973 (1980). Specification for prefabricated drainage stack units: galvanised steel.

BS 41421990. Method for rating industrial noise affecting mixed residential and industrial areas.

BS 4737. Intruder alarm systems.

BS 53251983. Code of practice for installation of textile floor coverings.

BS 5385. Wall and floor tiling. BS 5385:Part 3:1989. Code of practice for the design and installation of

ceramic floor tiles and mosaics.

BS 5395. Stairs, ladders and walkways. BS 5395:Part 2 1984. Code of practice for the design of helical and spiral

stairs.

BS 5446. Components of automatic fire alarm systems for residential

BS 5446:Part 1:1990. Specification for self-contained smoke alarms and premises.

point-type smoke detectors.

BS 55721978. Code of practice for sanitary pipework.


,

British Standards Institution publications

BS 5588. Fire precautions in the design, construction and use of buildings. BS 5588:Part 1:1990. Code of practice for residential buildings.

BS 5617d985. Specification for urea-formaldehyde (UF) foam systems suitable for thermal insulation of cavity walls with masonry or concrete inner and outer leaves.

BS 56181985. Code of practice for thermal insulation of cavity walls (with masonry or concrete inner and outer leaves) by filling with urea-formaldehyde (UF) foam systems.

BS 56l!%l978. Code of practice for design of housing for the convenience of disabled people.

BS 5628. Code of practice for use of masonry. BS 5628:Part 3:1985. Materials and components, design and workmanship.

BS 5839. Fire detection and alarm systems for buildings. BS 5839:Part 1:1988. Code of practice for system design, installation and

servicing.

BS 5M1989. Specification for installation in domestic premises of gas- fired ducted-air heaters of rated input not exceeding 60kW.

BS 618k1982. Code of practice for protective barriers in and about buildings.

BS 62621982. Code of practice for glazing for buildings.

BS 67W1987. Specification for design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages.

BS 67509%. Specification for modular coordination in building.

BS 8204. In-situ floonngs. BS 8204:Part 2:1987. Code of practice for concrete wearing surfaces.

BS 8206. Lighting for buildings. BS 8206Part 29992. Code of practice for daylighting.

BS 8208. Guide to assessment of suitability of external cavity walls for filling with thermal insulants.

BS 82l3. Windows, doors and rooflights. BS 8213:Part 1:1991. Code of practice for safety in use and during cleaning

of windows and doors (including guidance on cleaning materials and methods).

BS 8220. Guide for security of buildings against crime. BS 8220:Part 1:1986. Dwellings.

BS 83031986. Code of practice for installation of domestic heating and cooking appliances burning solid mineral fuels.


Index Above ground drainage, 200 Access

control options, 70 occupants’ requirements, 15 solar, 39

Accidents, 15,93 Active solar heating, 157 Activities, timing, 217 Activity zones

baths, 274 bidets, 276 kitchens, 239,250 sanitary appliances, 196 et seq showers, 275 washbasins, 275 WCs, 277

Adjustable heights of worktops, 260 Adventitious ventilation, 108 Affordable heating, 107 Air admittance valves (AAVs), 190 Air change rates, 158,174 Air paths in the structure, 169 Air quality, occupants’ requirements, 14 Air supply to heaters, 162 Air temperature, 20 Airing cupboards, 269 Airing, laundry, 269 Airtightness

testing of dwelling, 169 BREEAM criteria, 170

call systems, 210 fire, 210 smoke, 77,210

Altitude, effect, 24 Ambulant disabled people

Alarms

bathrooms for, 224 desirable design features for, 223 garden paths for, 224 provision for, 222 vehicles for, 224 WCs for, 224

Amenities, occupants’ requirements, 15 Annual efficiencies, boilers, 146 Annual energy cost, 107 Areas, play, 35 Armchair sizes, 225 Aspect, 25 Assessments, variability, 6 Attic space, 13 Awnings, 36

Back boiler systems, 146,148 Balance

negative energy, 36 positive energy, 36

for gas boilers, 163 terminal positions, 164

Balanced flue boilers, 145 Balanced flues

Balustrades, 94 Bamers, noise, 53 Basement stairs, 86 Bases of stacks, 198 Basket strainer wastes, 248

Bathroom layouts, typical, 279-281 Bathrooms, 273 et seq

check-list, 282 occupants’ requirements, 12 space relationships, 277

activity spaces, 274 sizes, 274

Baths

Beam and block floors, insulation, 133 Beam filling, effects of inadequate, 57 Beam-and-pot floors, 57 Bedrooms

check-list, 235 circulation, 215,232 occupants’ requirements, 12

Beds, sizes, 227 Below ground drainage, 189 Belts, shelter, 28 Bidets, sizes, 276 Block heating, 156 Boards

distribution, 209 draining, 248

Boiler energy management system (BEMS), 161

Boilers, 141 annual efficiencies, 146 back, 146 balanced flue, 145 coal 148 condensing, 145 electric storage, 149 flues, 163 gas, choosing between, 146 liquid petroleum gas (LPG), 147 oil, 148 open flued, 146 thermostats, 145

Boiling water heaters, 207 Bolts, hinge, 65 Branch discharge pipes, 195 BRE Domestic Energy Model

Breakers, circuit, 209 BREEAM (Building Research

Establishment Environmental Assessment Method), 4

(BREDEM), 110,138

BREEAM criteria airtightness, 170 gas, choosing between, 146 general, 113 mechanical ventilation with heat

refuse disposal, 206 storage of hazardous substances, 255 criteria, water conservation, 207

recovery, 181

Bridges, cold, 117 Brief, design, 3 Buffer space, conservatories, 38 Building Regulations

condensation, 118 insulation of hot water storage, 161 national, 78 radon, 185

Built-up areas, 25 Burglary, 61 Butane (LPG) for space and water

heating, 138

Carbon dioxide, 173 emissions from various fuels, 139 production, 112,113

Cast iron pipes, 200 Cavity walls, filling, 121 Ceilings

heating, avoidance of, 157 sound insulation of, 58 switches, 207

Central heating, warm air, 150 CFCs (chlorofluorocarbons), 4,118 Chains, door, 67 Check-lists

bathrooms, 282 kitchens, 261 living rooms and bedrooms, 233 et seq safety, 101 utility areas, 270 et seq

Circuit breakers, 209 Circulation, 11

bedrooms, 215,232 kitchens, 250 living rooms, 215 sitting and eating, 228 space between furniture, 231 space between furniture and walls, 231

Cleaning materials storage, 255 cupboards, 246

Cleaning windows, 99 Clearance

over stairs, 93 for furniture, check-list, 233

Climate control, site layout, 19 Cloakroom washbasins, 276 Closed circuit television (CCTV), 69 Clothes drying, 268 Coal boilers, 148 Coal store sizes, 149 Coal tar products, avoidance of, 171 Coils, heating, 159 Cold bridges, 117 Cold deck roofs, 119 Cold water supply, 207 Combi-boiler, 144 Combined drainage systems, 204 Combined heat and power (CHP), 156 Common stairs, 86 Communal heating systems, 156 Compartmentation, 89 Compressible insulation in floors, 133 Concentration of activities, 216 Concierges, 69 Concrete floors, 57 Concrete panel systems, 57 Condensation, 14

loft space, 119 Building Regulations, 118

Condensing boilers, 145 Condensing gas fires, 154 Conflicts

between requirements, 5 in the brief, 3

Conservatories, 38 Control layers, vapour, 118 Controller, humidistat, 178


Controls heating, 159 height of, 100

Convenience, occupants’ requirements,

Conventional flues, terminal positions,

Cookers, 249 hoods, 174 positioning, 258

Copper microbore piping system, 154 tubes, 200

Costs, fuel, 109 Courtyards, 35

Crime prevention

15

165

overshadowing, 44

external layout, 64 Police officers, 62

Crime survey, British, 61 Cross-flow heat exchangers, 183 Cupboards, 13,256

airing, 269 cleaning materials, 246 on external walls, 13 deep, 254 high, 254 shallow, 254,259 wall, 244

Curtains, 36 Cutlery, storage, 243 Cyclo-controlled systems, 160 Cylinders, 141

insulation, 161 primatic, 145 thermostats, 159,161

Damage, wind, 19 Damp-proof membranes, 133 Daylight, 43,45 Daylight factor (DF), 45 Daylighting, distribution, 45 Degree-days, 20,25 Delivered energy, 108 Delivery points, security, 73 Depressurisation, sub-floor, 185 Design

skills, 3 trade-offs, 5 windows, 36

Detection systems, intruder, 62,63 Development control, 19 Development of fires, 77 Dimensional co-ordination of kitchen

fittings, 241 Dining areas, check-list, 235 Disabled people see Ambulant disabled

people Discharge pipes

branch, 195 in high ambient temperatures, 202 waste disposal units, 204

Discharge rates, sanitary appliances, 190, 192

Dishwashers, 249 Distances

between buildings, 27

between pipe supports, 202 Distribution boards, 209 District heating, 156 Domestic hot water systems (dhw), 142 Door chains, 67 Doors

escape, 82 sliding, 244 sound insulation, 54,55

units, 131

below ground, 189 requirements, 189

Draining boards, 248 Draught lobbies, 11,169 Draught-stripping, 169 Drawers, kitchen unit, 243 Driving rain, 19,23 Dry pack, concrete panel systems, 57 Dry-core boilers, 149 Drying racks, 268 Ducts, 182

insulation, 161 passive stack ventilation, 177 service, 202

Dustbins, 206 Dwelling energy ratings, 111

Eating and sitting areas, circulation,

Economies, plumbing system design, 203 Efficiency, heating system, 108 Electric off-peak storage systems, 152 Electric storage boilers, 149 Electrical appliances, space, 243 Electrical services, 207 er seq

Electricity for space and water heating,

Energy

Double glazing, 45

Drainage

228-230

sound insulation, 58

138

costs, 107 delivered, 108 efficiency, 107 main flows, 110 primary, 108 rating for dwellings, 111,138 units, 108 useful, 108

Entrance doors, robustness, 65,66 Entrances, check-list, 232 Entryphones, security, 73 Escape

doors, 82 lockset, mortice, 71 route, flat roof, 85 windows, 82

Evacuated tubular solar heaters, 157 Evaluation of designs, 6 Exchangers, heat, 145,151 Exhaust gases, 146 Existing buildings, preserving sunlight,

39,47 Exits

alternative, from flats, 82 final, 79,86

Exposure, wind, 19

Extensions, overshadowing by, 44 External layout for crime prevention, 64 External lighting

crime prevention, 63 security, 68

location, 177 type, 177

Fabric heat loss rate, 108 Factor, sky, 47 Fans

controls, 178 extractor, 174 location, 177 sizing, 178 type, 177

Filled cavities, walls, 121 Final exit, 79 Fire

alarms, 210 dampers, cooker hoods, 182 escape doors, security, 72 precautions, passive stack ventilation,

safety

Extractor fans, 174

177

in dwellings, 77 signs, 85

structural protection, 89 Fires, gas, condensing, 154 Flanking sound transmission, 57 Flat plate solar heaters, 157 Flat roof

escape over, 85 insulation, 120

Flats, inner foyer doors, 71 Floating screed floors, sound insulation,

Floor finishes, slipperiness, 97 Floors

55

beam-and-pot, 57 compressible insulation, 133 concrete, 57 intermediate, timber, 56 sound insulation, 55

draught stabilisers, 162 to boilers, 163 room-sealed fan-assisted, 146

storage, 244 et seq waste disposal units, 204

Formaldehyde release, 173 Foul drains, 205 Freezers, 245 Fuel cost, 109 Fuels, main, for heating, 137 Furniture and equipment sizes, 225 et seq

Garden paths for ambulant disabled, 224 Gas

Flues

Food

boilers, choosing between, 146 fires, condensing, 154 for space and water heating, 138 heaters, balanced flues, 163 heaters, permanent ventilation, 162 room heaters. 154


Gas (cont)

Gases, exhaust, 146 Glass

supply, 211

transmission factor, 45 low-emissivity, 14

Glazed doors, safety, 95 Glazing

double, 45 main areas, 36

Global warming, 4 reduction of, 137

Green issues, 3,4 Greenhouse effect, 4 Grilles, 67

Grills, 249 Ground roughness, 27 Guards, lock and hinge, 71

Habitable room, prohibition of use as, 79 Hand washing provision, 267 Hardwood window frames, avoidance of,

131 HCFCs (hydrochlorofluorocarbons), 4,

118 Health and safety, occupants’

requirements, 15 Hearths to heaters, 163 Heat exchangers, 151,154

condensate drain, 182 cross-flow, 183

internal, 109 solar, 109

Heat losses, 108 Heat metering, individual, 156 Heat pumps, 157 Heat recovery, 180

Heat storage systems, water, 157 Heaters

passive stack ventilation 176

Heat gain

gas-fired systems, 151

boiling water, 207 hearths for, 163 immersion, 141,153,207 room, 141 wall, 154

affordable, 107 block, 156 coils, 159 communal systems, 156 controls, 159 occupants’ requirements, 13 space, 137 system design, central source 157 system design, individual rooms, 158 system efficiency, 108 systems, communal, 156 underfloor, 156 water, 137

wall cupboards above worktops, 259 sinks, 244 worktops, 243,260

buildings, effects of, 25

Heating

Heights of

High

cupboards, 254 shelves, 254

Highly exposed sites, 29 Hinge bolts, 65 Hobs, 249,250 Home-warm systems, 144 Hoods, cooker, 174 Hoppers, 206 Hot water systems

design, 159 unvented, 161

Hotplates, 249 Hourly mean wind speeds, 21 Hours of sunlight, 34 Housing design, optimal, 9 Humidistat controller, 178 Hydrofluorocarbons (HCFCs), 4,118 Hygiene, kitchen and laundry, 266

Illuminated switches, 208 Illumination levels, 209 Immersion heaters, 141,153,206 Impact noise, insulation against, 55 Index, driving rain, 23 Individual heat metering, 156 Infra-red detectors, passive, 65 Inner foyer doors, flats, 71 Installation, sinks, 248 Insulation

against impact noise, 55 against noise, 53 cylinder, 161 duct, 161 flat roofs, 120 pipe, 161 pitched roofs, 119 thermal, 117 thickness, walls, 121

Intermediate floors, timber, 56 Internal heat gains, 109 Intruder alarm systems, 74 Intruder detection systems, 62 Inverted roofs, 120 Ironing

clothes, 268 space, 269

Isolating valves, 206

Kitchen fittings, dimensional co-

Kitchens, 239 et seq check-list, 261 occupants’ requirements, 12 sinks, 247

sizes, 242,243 units, sizes, 242,243

Labelling of controls, 159 Laminated glass, 67,95 Landlord-controlled extract systems, 179 Landscaping, value, 28 Laundry, 265

sink, 267 storage, 266,269

site, 34 bathroom, 279-281

ordination, 241

Layout

staggered, 55 stepped, 55

Legionnaires’ disease, 171 Letter box, position, 66 Levels

illumination, 210 noise,52 ,

Lift dimensions, 222 Lights

fittings on stairs, 94

switches, 207 Light, rights to, 47 Lighting

strip,

natural, occupants’ requirements, 14 occupants’ requirements, 14 strip, 259

Linen storage, 269 Liquid petroleum gas (LPG) boilers, 147 Living areas

check-list, 234 circulation, 215 occupants’ requirements, 12 temperature, 13

draught, 169 sound insulation, 54

Lobbies

Locks and keys, safe keeping, 64 Locksets, mortice, 67 Louvre windows, 67 Low-emissivity glass, 14

Main entrance doors, flats, 70,71 Main flows of energy, 110 Mains pressurised system, 142 Maintenance

floors, 96 provision, pipework, 198,199

Mat wells, 95 Materials

cleaning, cupboards for, 246 for above ground drainage, 200

Maximum discharge rates for stacks, 193 Meals

preparation, 239 space for, 257

Means of escape flats, 82 maisonettes, 84 single family houses, 79

Mechanical extract ventilation (MEV),

Mechanical ventilation (MV), 180 180

systems, 180 with heat recovery, (MVHR), 180

Medicines, storage, 255 Membranes, damp-proof, 133 Meters

check-list, 232 positioning, 13 prepayment, 209 security, 73

Micro combined heat and power, 156 Microbore piping system, copper, 154 Microwave ovens, 250 Mild steel tubes, 201 Mobility standards, 222

292 BRE housing des@ handbook

Mortice locksets, 67 Mould growth, 117 Multi-gang switches, 208 Mutual obstruction, 43

Naphthalene, products emitting, 172 National Home Energy Rating (NHER),

Negative energy balance, 36 Noise, 51

111

barriers, 53 control, 10 insulation against, 53 insulation, windows, 53 levels, 52 limitation, sanitary appliances, 194 plumbing, 54 road traffic, 52 units, 52

Non-slip floors, 96

Obstruction, mutual, 43 Occupants’ requirements, 9 Off-peak electric storage systems, 152 Off-peak rate, 109 Offsets, pipes, 198 Oil boilers, 148 Oil for space and water heating, 138 Open flued boilers, 146, Open risers, 94 Open vented pressurisation system, 141 Operating instructions for heating, 13 Optimal housing design, 9 Options for access control, 70 Orientation, 43

Outlet terminal positioning, passive

Ovens, 249

check-list, 232

stack, 176

high level, space, 252 low level, space, 252 microwave, 250

Overlap of activity spaces, bathrooms,

Overshadowing, 29,44 Ozone layer, 4

Paraffin for space and water heating, 138 Parker Morris Report, 12 Parking, occupants’ requirements, 15 Partitions, sound insulation, 54 Passive infra-red detectors, 65 Passive solar buildings, 39 Passive stack ventilation, 176 Paths, air, in the structure, 169 Performance requirements, 4 Permanent ventilation, gas heaters, 162 Pianos, sizes, 225 Pipes

cast iron; 200 discharge, branch, 195 discharge, in high ambient

temperatures, 202 insulation, 161 offsets, 198 plastics, 201 suppox‘t distances, 202 waste, runs, 198

278

Pipework maintenance provision, 198,

Pitched roofs, insulation for, 119 Planning requirements, 3 Plastics pipes, 201 Play areas, 35 Plumbing

199

design, 194 et seq layouts, standardisation, 203 noise, 54 system design economies, 203 sanitary, 189

Police officers, crime prevention, 62 Pollutants, 171 Pontiac fever, 171 Porches, 265 Porters, 69 Positive energy balance, 36 Prams, check-list, 232 Preparation of meals, 239 Prepayment meters, 209 Prescriptive requirements, 4 Preservatives, wood, 174 Primary energy, 108 Primatic cylinders, 145 Privacy, 10

check-list, 233 domestic, 11

Private stairs, sizes, 93 Projecting windows, avoidance, 98 Propane (LPG) for space and water

Protected stairs, 79,86 Pumps, heat, 157

Quality in housing, 3

Racks, clothes drying, 268 Radiators, 141,161

sizes, typical, 153 Radon, 185

description, 173 protective membrane, 185 routes into houses, 174

safety, 98 support, 223

heating, 138

Rails

Rain, driving, 19,23 Ratings, energy, for dwellings, 111 Refrigerators, 245,255 Refuse collection

check-list, 232 disposal systems, 206 occupants’ requirements, 15

Regional climates, 20 Relationship between people,

Resident-controlled access, flats, 69 Residual current devices (RCDs), 209 Ridge terminals, passive stack

ventilation, 176 Rights t o light, 47 Risers, open, 94 Road traffic noise, 52 Rocker switches, 208 Roof construction against noise, 53 Roof spaces, ventilation, 184

requirements and components, 9

Roofs cold deck, 119 pitched, insulation, 119

Room heaters, 141 gas, 154

Room layout, for sunlight, 37 Room thermostats, 159,160 Room-in-the-roof, 119 Room-sealed fan assisted flues, 146 Running costs, heating systems, 138

Safety, 93 check-list, 101 devices, unvented systems, 143 rails, 98

activity spaces, 196 et seq discharge rates, 190,192 noise limitation, 194

Sanitary plumbing, 189 Sanitary systems, thermal movement in,

Screed, minimum thickness, 133 Screening, for reducing noise, 10 Sealed central heating systems, 142 Security, 61

Sanitary appliances

194

occupants’ requirements, 15 of windows in flats, 72

Sensors, weather, external, 160 Separating walls, beam filling in, 58 Service ducts, 202 Services

electrical, 207 et seq requirements, 189

Shading for solar control, 26 Shadow plan, 39 Shallow cupboards, 254,259 Shelter belts, 28 Shelves, high, 254 Showers, 194

activity spaces, 275 sizes, 275 valves, 207

Shutters, 67 Signs, fire safety, 85 Single stack drainage systems, 190 Single steps, avoidance of, 93 Sinks, 253

heights, 244 installation, 248 kitchen, 247

laundry, 267 positioning, 258

Site layout, 34 for climate control, 19

Sitting and eating areas, circulation, 228,229,230

Sizes, furniture and equipment, 225 et seq

Sky factor, 47 Sliding doors, 244 Slip-resistant floors, 95 Smells, 173 Smoke, 173 Smoke alarms, 77,210 Socket outlets

sizes of, 242,243

general provision, 208

BRE housing design handbook 293 __ ~.

Socket outlets (cont) location of, 208

Solar access, 39 Solar control, shading for, 26 Solar gain, winter, 33,109 Solar heating, active, 157 Solar radiation, 22 Solid fuel for space and water heating,

138 Sound insulation, 10

ceilings, 58 doors, 54 electrical services, 58 flanking, 57 floating screed floors, 55 floors, 55 lobby, 54 partitions, 54 stairs, 55

Space between furniture, circulation, 231 Space for

electrical appliances, 243 heating systems, 138 ironing, 269 meals, 257 ovens, 252

Space heating, 137 Spiral stairs, 94 Stabilisers, flue draught, 162 Stack bases, 198 Stack effect, maximising, 176 Stack vents, 190 Stacks

maximum discharge rates, 193 stub, 194

Staggered layouts, 55 Stairs

protected, 79,86 sound insulation, 55 winding, 15

Standard Assessment Procedure (SAP), 111

Standard designs, 6 Standardisation of plumbing layouts, 203 Standards for wheelchair access, 224 Starpoint, 111 Stepped layouts, 55 Storage

cutlery, 243 food, 244 er seq laundry, 266,269 linen, 269 medicines, 255 occupants’ requirements, 13

Storage systems, cold water, 207 Storage tanks (LPG), 147 Storage, occupants’ requirements, 13 Stores, coal, sizes, 149 Strainer wastes, basket, 248 Strip lighting, 259 Structural fire protection, 89 Stub stacks, 194 Sub-floor depressurisation, 185 Sunlighting, 33

existing buildings, 39 hours, 34

Supply of gas, 211 Support rails, 223

Surface water drains, 205 Surveillance, 61 Switches

ceiling, 207 light, 207 time, 159

System design, hot water, 159

Table sizes, 225 Table tennis table sizes, 226 Tariffs, 109 Telephones, 210 Television watching, 210,215 Temperature

external air, 20 living room, 13 recommended for spaces, 158

Terminal positions, balanced flues, 164 conventional flues, 165

Terminals, ducts, 182 Testing for airtightness, 169 Thermal insulation, 117

Thermal movement, in sanitary systems,

Thermostatic valves, 159, 160,206 Thermostats

timber frame construction, 121

194

boilers, 145 cylinder, 159 room, 159

Thresholds, 95 Timber floors, vapour control layer,

Timber frame construction, thermal

Timber intermediate floors, 56 Time switches, 159 Timing of activities, 217 Tobacco smoking, pollution, 173 Toughened glass, 95 Trade-offs in design, 5 Transmission factor, glass, 45 Traps, 189

vent pipe distances, 195 Trees, effects, 26 Trickle ventilators, 175 Tubes

avoidance, 134

insulation, 121

copper, 200 mild steel, 201

Tumble-driers, 268 venting, 183

Typical radiator sizes, 153

Underfloor heating, 156 Units

storage, 255,259

Units of measurement energy, 108 noise, 52

143

for hazardous substances, 255

Unvented domestic hot water systems,

Unvented hot water systems, 161 Urea formaldehyde foamed insulation,

172 Useful energy, 108 User requirements, 4

Utility areas, check-list, 270 et seq

Valves isolating, 206 shower, 207 thermostatic, 159,160,206

Vandalism, 61 Vapour control layers, 118

in timber floors, avoidance, 134 Vegetation, effects, 26 Vehicle access for ambulant disabled,

Vent pipe distances from trap, 195 Ventilated food cupboard, 245 Ventilation

224

adventitious, 108 occupants’ requirements, 14

roof spaces, 184 systems, whole house, 180 under floors, 185 underfloor, 162

bathrooms and shower rooms, 175 habitable rooms, 174 kitchens, 174 separate toilets, 175 utility rooms, 175

Ventilators, 14 trickle. 175

Venting drainage systems, 189 tumble driers, 183

stacks, 190 tumble driers, 268

Vertical zoning of storage, 256 Vertigo, avoidance, 98 View, 46 Volatile organic chemicals (VOCs), 172

Waldram diagram, 47 Wall cupboards, 244

height, 259 Wall heaters, 154 Wardrobe sues, 227 Warm air central heating, 150 Warm deck roofs

(inverted), 120 (sandwich) roofs, 120

Washbasin cloakrooms, 276 sizes, 275

passive stack, 176 I‘

Ventilation requirements, 169

Vents

Washing machines, sizes, 267 Waste disposal units, food, 204 Waste pipes, runs, 198 Wastes, basket strainer, 248 Watching television, 215 Water

conservation, 207 heat storage systems, 158 heating, 137 services, 206 et seq vapour, 173

activity spaces, 277 sizes, 276

WCS

Weather sensors, external, 160


,

Wheelchair standards, 224 Wheelchair users, provision for, 222 Whole house ventilation systems, 180 Wind, 21

damage, 19 direction, 26 effects, sanitary systems, 199 exposure, 19 shelter, benefits, 19 speeds, hourly mean, 21

Wind-chill, 19,24 Windbreaks, 26 Winders, 94 Winding stairs, 15 Windows

cleaning, 99 design, 36 escape, 82 flats, security, 72 noise insulation, 53 vulnerability to burglary, 67

Winter solar gain, 33 Wood preservatives, health and safety

aspects, 174 Worktops, 243,253

heights, 243,260

Zoning, for heating design, 160


BR 253