Introduction • Agenda • Learning Aims • Brett Martinc.wcea.education/training/file/1126760620f1f11673a358f... · 2014. 10. 7. · Section 2 – Rainwater Harvesting Systems

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Introduction • Agenda • Learning Aims • Brett Martin

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Agenda

Introduction – Learning aims – Brett Martin

Section 1 – Why Harvest Rainwater? Our Demand for water

The cost of water

Population growth

Climate Change

Legislation

Section 2 – Rainwater Harvesting Systems Key components

Design & Application

Calculating storage capacity

Tank installation

Section 3 – Conclusion (Learning outcomes), Q&A


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Learning aims

• To outline the key factors which place pressure on

water resources.

• To demonstrate how RW Harvesting can contribute to providing a sustainable water resource.

• To gain a full appreciation of the legislative requirements in place to conserve water.

• To understand the options & key components associated with a RW Harvesting system.


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Brett Martin Plumbing & Drainage • Part of the Brett Martin Group of Companies

• Manufacturers of specialist plastics

• Turnover £112 million

• HQ in Co Antrim

• P&D Division HQ in Derbyshire

• Export to 70 countries

• Employ over 800 people

• Over 6 sites


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Service & Support

•Certification & Accreditation

•Expert Technical Advice


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Our demand for water

Water for life

Our demand for water -- The cost of water -- Population Growth -- Climate Change -- Legislation

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150 Litres The amount of water used pppd

50% Could be supplied by

rainwater harvesting

How we use our water in the home


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Embedded Water

3400Litres pppd

2608 Litres (689 gallons) of water

to produce 3.8 Litres (1 gallon) of Beer

65% of water we consume is in our food

One slice of bread requires

40 Litres of water


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Water metering UK Average household water bill for 2012-13

Water bills will increase on Average 3.5% April 2013 – March 2014


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Water metering

30% - UK Households have a water meter

10% - Household water consumption is reduced after a meter is fitted. Surface water Rebate - If no surface water from your property enters a public sewer then you may qualify for a reduction in your sewerage charge ('surface water drainage rebate').


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The daily cost of domestic water use


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The Anglian Water region

£2 billion (2010-2015)

Investment to improve water services.

£588 million To meet the demand of 145000 new

homes.

6 million customers,

20% population growth in 20 years


One the driest regions of the country.

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Population Growth ONS data

62.2 million

UK population (2010)

Rising to 67.2 million by 2020

Reaching 70 million by 2027

In 2000 UK population was 58.8 million Are living Longer? 1 in 6 (16.4%) of the population are 65 and over


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The surface area of England by land use

Population Growth Are we a crowded Island?

The UK population as 247 inhabitants per square kilometre.

Compared with the Netherlands 395

Belgium 341

Japan 339


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Population Growth – Housing Shortage

300,000 new homes required each year.

The industry is currently producing 100,000 new homes each year.

At the height of the market in 2007,

over 190,000 new homes were built.


The Future Homes Commission (October 2012) set by the RIBA

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Climate Change

‘It is too early to say whether the weather we've witnessed over the last three

years demonstrates that the climate is definitely changing,

But we have certainly seen exceptional weather with high temperatures and

droughts causing significant problems’

In stark contrast, this was then followed by the wettest April to September on

record, which resulted in many people suffering the misery of being flooded’

Dr Paul Leinster, Chief Executive of the Environment Agency – Dec 2012 Our demand for water -- The cost of water -- Population Growth -- Climate Change -- Legislation

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Climate Change – Winter floods 2014

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Climate Change – Drought

Sept 2010 to March 2012

Many parts of England experienced the driest

18 months for over 100 years

April 2012

Seven water companies in the South &

East of England imposed a ‘temporary use ban’

on 20 million customers to conserve resources.


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Climate Change – Rainfall & Floods

April – September 2012

The wettest period on record, over 4500 properties flooded.

Around 5 million people, in 2 million properties, live in flood risk areas in

England and Wales.

Floods are now on average nearly twice as

frequent as they were 100 years ago.


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Climate Change – Rainfall & Floods

Summer floods of 2007

• Over 55,000 homes & businesses were flooded.

• Estimated insurance losses at £3 billion.

Surface water flooding

Two thirds of properties flooded was

because drains & sewers were overwhelmed.

Currently 80,000 properties are at very significant risk from surface water flooding.


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Legislation – The Code for Sustainable Homes

The Code for Sustainable Homes (the Code) is an environmental assessment method

for rating and certifying the performance of new homes.

It is a national standard for use in the design and construction of new home

with a view to encouraging continuous improvement in sustainable home building.

The code covers 9 categories of sustainable design.

2 of which concern water usage & have mandatory

performance requirements.


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Code for Sustainable Homes - Category 2 – Water – Wat1 - Internal Water Use

• Aim – To reduce the consumption of potable water in the home

• To achieve Levels 5 & 6 (80 Litres p/day) rainwater or greywater recycling will be required

• By 2016 all new homes must comply to level 6


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Code for Sustainable Homes

Category 2 – Water – Wat2 – External Water Use

• Aim - To encourage the recycling of rainwater and reduce the amount of mains

potable water used for external water uses.

• The simplest method for rainwater collection is a water butt.

• A rainwater harvesting system can contribute to Wat1 & 2


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Category 4 – Surface Water Run-Off – Sur1

Aim - To design housing developments which avoid, reduce and delay the discharge of

rainfall to public sewers and watercourses.

This will protect watercourses and reduce the risk of localised flooding, pollution and other

environmental damage.

Specifying rainwater recycling as part of a sustainable drainage system (SUDS) to manage

surface water run-off.


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Category 4 – Surface Water Run-Off – Sur2 – Flood Risk

Aim - To encourage housing development in low flood risk areas, or to take measures

to reduce the impact of flooding on houses built in areas with a medium or high risk

of flooding.


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Legislation

Building Regulations Approved Document

Part G


G – Water Efficiency

125 Litres ppd of wholesome water

consumptions

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Legislation

Other legislation & standards to consider:-

Building Regulations Approved Document H & G

H - Drainage & Waste Disposal

BS8515:2009

The BSI rainwater harvesting code of practice

PPS25 – Planning Policy Statement 25

Development and flood Risk Practice Guide.

Environmental assessment method

best practice in sustainable design


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Section 2

Rainwater Harvesting Systems

• Key Components

• Storage Capacity

• Design & Application

• Tank Installation

• Maintenance

Key Components -- Storage Capacity -- Design & Application -- Tank Installation -- Maintenance

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Rainwater Harvesting Home & Garden Systems

Direct Feed System


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Rainwater Harvesting Home & Garden Systems

Gravity Feed System

• Additional cost of header tank & associated

plumbing.

• Restricted by building design

• Warm loft space temperatures;

potential breeding grown for Legionnaires.

• The benefit of a stored water supply;


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Rainwater Harvesting

Key components

• Pipework

• Filter Unit

• Calming Inlet

• Floating intake

• Pump & Control Unit


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Key components – Pipework

In accordance with BS8515 & WRAS

Pipework for non potable water (rainwater)

Recommended pipes should be Green or

Black & Green.

Blue pipework is a recognized standard used

for potable water.

Not for drinking water


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Key components – Filter Unit

• To comply with BS8515:2009

• Designed as a ‘in-tank’ or ‘pre-tank’ filter

• Stainless steel –water & weather resistant

• Removable 35 micron fine mesh filter

• 15˚ fall on flow

• 3 x 110mm inlets (160mm Channel option)

Independently tested at Newcastle University for flow efficiency.

Achieved 98% efficiency on flow rates up to 5 litres per second


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Key components

Calming Inlet

• To comply with BS8515:2009

• Fitted to drainage pipe feeding

rainwater into storage tank.

• Minimises turbulence, slows water

flow into tank

• Prevents disturbance of any sediment

at the base of the tank

• Ensures oxygenation, to discourage Algae growth Key Components -- Storage Capacity -- Design & Application -- Tank Installation -- Maintenance

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Key components

Floating Intake

• In accordance with BS8515:2009

• Extracts the cleanest water available.

• Located approximately 100 to 150mm

below the surface of the water.

• Further filters the water.


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Key components

Submersible Pump

• Direct feed system.

• Delivers water to the point of demand.

• In the unlikely event that there is no

water in the tank:-

The system is equipped with run dry protection.

Pump will switch off to prevent burn out.

Pump should be removable for maintenance purposes


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Key components – Control Unit

Tundish – AA Air Gap Prevents ‘backflow’ & contamination

of mains water supply, meets requirements of

BS EN 13076

Float switch Should the tank run dry the float switch will drop to

provide mains water back up.

Positioned around 300mm from base of tank


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Design & Application – RWH

Low profile tank Systems

• 1500 Litre tank weighs only 62 kilos (9.5 stone)

• Can be lifted by two persons, reduces the requirement

for plant machinery.

• Easier access through properties

(through doorways)

• Lower levels of excavation.


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Low profile tank systems

• Multiple tank connections

• Large underground storage

• Attenuation


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Commercial Systems

•Hotels

•Offices

•Leisure Facilities

•Schools

•Industrial Buildings

•Flushing Toilets

•Irrigation

•Laundry

•General Cleaning

•Vehicle Washing

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Calculating Storage Capacity

In accordance with BS8515:2009

The following factors should be identified in order

to calculate the size of the system;

• The amount & intensity of rainfall

• The size & type of collection surface

• The number & type of intended applications, both present & future

As set out in BS8515:2009 – The three approaches, simplified, intermediate &

detailed, are recommended for sizing. Key Components -- Storage Capacity -- Design & Application -- Tank Installation -- Maintenance

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Building

Guttering &

pipework

Catchment surface

Runoff losses

Yield Co efficient 0.8

Rainfall

Filter efficiency 0.9 Storage Tank

Calculating storage capacity The intermediate approach

Roof Area –168.75m²

Annual Rainfall – 1151.9mm

(Taken from Cardiff Weather station)

Annual rainwater yield

Roof area in m² 168.75

X

Annual regional rainfall in mm 1151.9

X

Yield Coefficient % 0.8

X

Filter efficiency 0.9

= 139955.84

5% of Annual rainfall 6997.80

(18 days) litres


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Building

Guttering &

pipework

Catchment surface

Effective runoff

Rainfall

Storage Tank


Calculating storage capacity The intermediate approach

WC

Annual (non-potable) water demand

Daily requirement per person 75 Litres

X

Number of persons per dwelling 2

X

365 days per year

= 54750

5% Annual (non potable) water demand 2737.50

(18 days)

Do not oversize the tank!

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Tank Installation

In accordance with BS8515:2009

To ensure structural stability the following

issues should be considered.

• Avoiding flotation

• Resisting ground pressures

• Water table fluctuations

• Resisting vehicle loadings


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Polyethylene material (HDPE)

Rotationally moulded one piece mould

Lightweight material

Excellent impact resistance

High tensile strength

GRP Tanks

Brittle material.

Potential for tank to split/crack, through

tensile stress.

Susceptible to ‘creep’

Graf Tanks

German manufacture

Two piece mould

Requires on-site construction, labour

intensive.

Sealing requires testing with large

volume of water.

Tank Installation


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Tank Installation

Excavation area Height 2.55m

Width 1.56m

Depth 1.56m

Total 6.21m³

Complete Tank Volume – 2.382m³

Therefore 3.828m³ concrete required!

£100 to £150 per M³ of Concrete (depending on plant location)

Plus cost of plant & labour


Figures calculated on a 2000litre tank

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Tank Installation

250mm Slab Base Depth

Vehicle Loading A load bearing slab should

be constructed

Filter run off

& overflow

Concrete Surround To be poured & completed in

multiple lift (approx 300mm)

Fill tank Continue to fill tank with water

whilst backfilling

Ensure water level remains

300mm above concrete level


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Maintenance guidance in accordance with BS8515:2009

& as per manufacturers instruction.

Gutters/Downpipes - Annual inspection

Filter- Annual inspection

Storage Tank- Annual inspection

Pump & Controls (associated fittings) - Annual inspection

Wiring- Annual inspection

Pipework- Annual inspection

Storage Tank - Drained down & cleaned – every 10 years

(dependant on usage)


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Maintenance - Commissioning

• Poor installation

‘Read installation instruction’

• Ensure there is no debris in the tank or pipework.

• System should be flushed before use, open an appliance to create demand.

• Ensure there are no leaks in the pipework

Pump will continue to run, increasing water temperature, tripping mains top-up

• Pay-back period – depending on which web-site you read!

Estimated 10-15 years

Dependant on area, amount of rainfall & cost of mains water


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Design & Application – Domestic RWH Home & Garden System


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Design & Application – Agriculture RWH Garden System


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Design & Application – Agriculture RWH Garden System


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Design & Application – Domestic

RWH Home & Garden System


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To Conclude, learning outcomes;

Harvesting rainwater can ease the pressure placed on our water

resources, caused by factors such as climate change & population

growth.

Contributing to providing a sustainable water resource with the

capabilities to satisfy legislation and the potential to save money.

Thank you, any questions?

Conclusion --- Thank you

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Brett Martin Plumbing & Drainage Email. [email protected]

Tel: 01246 280000

Mobile: 07900 906157

Websites: www.brettmartin.com

www.ribaproductselector.com

Conclusion --- Thank you

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We also supply:-

Grease Traps

Sewage Treatment systems

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Documents

Introduction • Agenda • Learning Aims • Brett Martinc.wcea.education/training/file/1126760620f1f11673a358f... · 2014. 10. 7. · Section 2 – Rainwater Harvesting Systems