VEKA Group - A Guide to Sustainable Curtain Walling Final

7/30/2019 VEKA Group - A Guide to Sustainable Curtain Walling Final

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A Guide toSustainable

Aluminium CurtainWalling

Continuing ProfessionalDevelopment Seminar


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Welcome to

X Architects

Continuing Professional Development(CPD) Presentation by

Mr X

Bowater Architectural Limited

A Guide to Sustainable

Aluminium Curtain Walling


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Agenda of Todays CPD Seminar

1. Bowater Introduction

2. What is Curtain Walling?

3. Types of Curtain Walling Systems

4. Design Criteria

5. Regulation & Standards

6. Environmental Considerations

7. Case Studies

8. Conclusion

9. Q&A

10. Further Study


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The VEKA Group


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Learning Objectives of Todays

CPD Seminar

An introduction to the principles of curtain walling, specificallydiscussing related sustainability issues and including:

What is curtain walling?

Types of curtain walling systems

Design criteria

Regulations & Standards


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Traditionally it was the name givento the outermost wall surrounding acastle or similar building

Curtain walling is a form of vertical

building enclosure which supports no

load other than its own weight, that ofancillary components and the

environmental forces which act upon it

For our purposes, it describes a

glazed screen in any area of a building

and is usually supported from the floor

slab and / or from intermediate fixings

e.g. steel beams or floor slabs


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Oriel Chambers in Liverpool,England was one of the worldsfirst metal framed glass curtainwalled building in 1864 designedby local architect Peter Ellis.

The extensive glass walls allowedlight to penetrate further into thebuilding utilising more floor spaceand reducing lighting costs in

short winter months.

The stone mullions are decorative


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It is a non-structural method ofenclosing a vertical space by use of

glazed cladding

It can be used to any height (withinreason).

Highly flexible kit of parts thatallows the architect / specifier manydesign freedoms and opportunities

Glass curtain wall of the Bauhaus, Dessau


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2. Types of Curtain Walling System

- Stick

Stick Curtain Wall is supplied inpre-machined mullions and transoms

for site assembly and installation

Used as vertical and sloped facadeson buildings

Performance of the system dependsupon the quality of the installation

Mostly used on low to medium riseapplications where there is a highdegree of uniformity and relativesimplicity of design


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- Unitised Unitised Curtain Wall is supplied instorey height, pre-assembled panelsand may include factory fitted glazing

Units are hung from buildingstructure to form enclosure and oftenused in high-rise applications,particularly in difficult access areas

Pre-assembly guarantees qualitydue to fabrication in a controlledenvironment

Fast site installation

Lower on-site installation costs withstandard scaffolding not required


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- Bespoke and Rainscreen

Bespoke Curtain Wall- Typically high specification, complex, large span projects

- Potential Long lead-in times, due to long design period

Structural Glazing / RainscreenUnframed panes of glass that are attached to a buildingssupport structures using silicone adhesive or bolt connectors

Roof GlazingModified versions of vertical stick curtain wall systems


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3. Design Criteria

Ten Issues to Consider :-

1) Material2) Loads

3) Spans4) Fixings5) Weather Performance6) Thermal Performance7) Ventilation

8) Cleaning and Maintenance9) Appearance and Finish10) Glazing / Panels


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3. Design Criteria - Material

Curtain Walling can be made of aluminium, PVC-U, steel or

timber Aluminium represents 80% of the market.

Why is aluminium the most popular material for curtain

walling? Relative strength to weight ratio

Life span

Flexibility

Serviceability Grid structure


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3. Design Criteria - Material

Strength to weight ratio = specificstrength

Component TensileStrength

Density SpecificStrength

FormabilityVersatility

OverallRating

Aluminium 600 2.7 222.22 9 2000

Steel 2000 7.86 254.45 6 1527

Oak 60 0.69 86.96 7 609

PVC 14 1.4 10.00 10 100

Concrete 10 2.3 4.35 1 4


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3. Design Criteria - Loads

Dead Loads

Wind LoadsCalculated using BS6399based on local windspeed, topography,

height above sea level,distance from sea andincluding potentialchanges to adjacentbuildings or effects of

the surroundings

Typical Flow Patternaround a high,rectangular building

Wind velocities in zones A& B may be twice that offree wind at the sameheight

A

B

B


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3. Design Criteria - Loads

Seismic Loads

Snow Loads

Thermal Loads

Blast Loads

Terrorist attack Oklahoma City, USA in 1995 in which resultingexplosion killed 168 people


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3. Design Criteria - Spans


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The Curtain Walling can be fixed back to the structure in a

number of ways:

1. Fix to floors 2. Fix between floors 3. Fix to edge beam 4. Fix to Wind post 5. Combination

3. Design Criteria - Fixings


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Typically, fixings can be fabricated from:

Steel or aluminium angles

Customised extruded shapes

Steel or aluminium spigots


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3. Design Criteria


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3. Design Criteria


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System10 Aluminium Keyway System


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3. Design Criteria-Weather Performance

There are two methods of drainage used by the major systems:

Mullion DrainedAny water that enters into the system runs along thetransoms, and runs down the mullions to the floor andthe outside

Zone or Field DrainedAny water that enters into the system passes throughslots in the pressure plates and external transom caps


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3. Design Criteria

Pressure EqualisationAll systems approved by the CWCT

must be fully sealed and pressureequalised - which means that thepressure inside the system must bethe same as that externally. Thisencourages drainage to the outside,

mainly through the mullions. Allinternal joints must be sealed toensure that air penetration is notpossible

Diagram showing the generalisedpattern of wetting on a zone in awindward facing elevation


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3. Design Criteria-Thermal Performance

is the amount of heat

transferred through a material.The lower the U-value,the slower the rate of heat flow

and the better the insulating quality


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3. Design Criteria-Thermal Performance

Typically, the industry is looking for 2.0 W/m2K or better

Bowater Architectural curtain walling can achieve 1.0W/m2K

The basic design recommendations are:

Keep the metal on the outside in glazed screens to a minimum

Avoid small pane sizes

More glass than frame


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3. Design Criteria - Ventilation

Ventilation can be provided by:

Glaze in trickle vents (in the glass area) or slot vents

Opening windows including features such as night ventlocking

Alternative methods e.g. through the eaves, spandrel panels,or mechanical ventilation

Louvres Electronically operated sash openers


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3. Design Criteria- Cleaning & Maintenance

It should always be

remembered that CurtainWalling cannot normally becleaned from the inside, andexternal means such as scissorlifts or cherry pickers are

required for low rise buildingsor cradles for high rise.


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3. Design Criteria - Finishes

Aluminium can be treated to enhance a buildings appearance,most often by polyester powder coating (PPC) or anodising.

Finishes available:

Polyester Powder Coat (PPC), wide range of standardcolours

Syntha Pulvin

Interpon D

Anodising Silver (natural)

Bronze

Coloured


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3. Design Criteria - Glazing / Panels

Glazing Vision Areas

For vision areas, glass is the only reliable option.

Glass can retain heat, expel heat, be clear or obscure. It canbe screen printed, toughened, or have safety inter-layers(which can also provide obscurity). It can also be patterned,can be self-cleaning or can be look-alike backed with insulationand can have acoustic effects as well as many other attributes.

Infill or spandrel panels can be made in many materials such asaluminium, steel, plastic, composite or solar.


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4. Regulations & Standards

Building Regulations:Part L Conservation of Fuel & PowerPart F VentilationPart N Glazing Safety in relation to impact, opening and

cleaning

Standards / Codes of Practice:BS EN 13830 Specification for Curtain WallingBS EN 12207 Air Permeability Classification

BS EN 12208 Water tightness ClassificationBS EN 12210 Resistance to Wind Load Classification

BS 6262 Code of Practice for Glazing of BuildingsBS 6399 Wind Load

CWCT Testing (Centre for Window & Cladding Technology)

Code for Sustainable Homes (CSH)


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4. Regulations & Standards

-CWCT required specifications

Type of test Standard Result

Air permeability BS EN 12153:2000CWCT Section 5

600 Pa

Water tightness

under static pressure

BS EN 12155:2000

CWCT Section 6600 Pa

Wind resistance

serviceability

BS EN 12179:2000

CWCT Section11

2400 Pa

Water penetration

dynamic aero engineCWCT Section 7 600 Pa

Water penetration

hose testCWCT Section 9 no leakage

Wind resistance

safety CWCT Section 12 3600 Pa

Impact resistance

heavy soft bodyCWCT Section 15

no damage

no deformation


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Test screen size 7.2 m x 8.0 m with 42 fixed lights


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Rigorous testing -screen exposed to 14,170 litres

per hour


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Water penetration dynamic aero engine


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Water penetration hose test


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Window testing versus CW testing

Window CW screen Difference

Window/screen size 1.30 m x 1.30 m 7.20 m x 8.00 m

Total area 1.69 m 57.60 m 3300%

Air permeability 600 Pa 600 Pa

Water tightness 300 Pa 600 Pa 100%

Wind resistance 2000 Pa 2400 Pa 20%


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Curtain Walling Testing versus Nature

Highest Rainfall 24 hours

Monsoon on record in India

1,840 litres/day.m2

Curtain Walling water flowexposure over 24 hours

5,904 litres/day.m2

Ratio 24 hours CurtainWalling Testing vs Monsoon

3.2:1

Curtain Walling Water flowintensity

340,070 litres/day/area

Total Curtain Walling ScreenArea

57.60m2


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Durability

Component Material

Design life

BS 7543:2003

Table 2

Life expectancy

Curtain wall sections Aluminium 6063 T6 30 years 60 years

Powder coating Polyester 20 years over 25 years

Fixing brackets Aluminium 6063 T6 30 years 60 years

Fixing screws Stainless steel 30 years 60 years

Thermal break PVC-U 30 years over 35 years

External gasket co-extruded TPE 10 years over 10 years

Internal gasket EPDM 10 years over 10 years

Butyl shim tape EPDM shim cord 20 years over 20 years

Double/triple glazing Float/low E glass 30 years 10 to 30 yeas

Assembly sealants Silicone 30 years 60 years


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5. Environmental considerations

- Why choose aluminium? Availability: Aluminium is made from Bauxite, the third most

abundant element in the Earths Crust*

It is not oil based and current known supplies will last 300 years*

Environment: 60% of the energy used in processing is hydro-electric*

The industry only mines approximately 1 sq mile per annum*

Life Span: Aluminium does not rust, is corrosion resistant andtherefore has a long life

Weight: Lightweight, it is only one third of the weight of steel Recyclability: Aluminium is fully recyclable with minimal loss in

quality*

Requires only 5% of initial energy to recycle*

Maintains a good recycling value

At least 70% Building industry scrap is recycled*

Flexibility: Aluminium can be extruded to high tolerances and can bedesigned to incorporate aesthetically attractive features

*Source:- ALFED Aluminium Federation

i l id i


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- External Solar Shading Purpose:

Maintain 24C in offices and schoolsduring summer peak

Overheating prevention, CO2 andenergy cost reduction

Total solar gain is limited to 35W/m (Part L2)

The Challenge is to maximise theday light entry, whilst minimisingsolar gain

5 E i t l id ti


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- Photovoltaic Consider:

Photovoltaic (PV) offers the abilityto generate electricity in a clean,quiet, renewable way

Commercial PV systems can

generate electricity for export tothe National Grid

Availability of preferential feed-in

tariffs for solar-generatedelectricity

6 C St d


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6. Case Study

- Curtain walling in Notting Hill

6 Case Study


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6. Case Study

- Curtain walling in Notting Hill


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Riverside College project brief

5 Elevations

Remove existing facades

Design, manufacture and install new curtain wall screens

Project size 1970 square metres

Minimal disruption to college

8 week contract period


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Elevation 2 - Before


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Elevation 2 - After


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We delivered our promise

On site for only 5 weeks

The college opened on Monday 7th

September for enrolment with a newfaade and no disruption to the College

7 Conclusion


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7. Conclusion

Curtain walling is highly flexible allowing you the architect manydesign freedoms and opportunities

Design criteria of: material, load, span, fixings, weatherperformance, thermal performance, ventilation, cleaning andmaintenance, appearance and finish, glazing / panels

7 Conclusion


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7. Conclusion

4. Choose energy efficient systems

5. Solar shading 6. Photovoltaic


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Why Bowater Architectural?

A Revolution with Heritage

Code for Sustainable HomesAesthetics and Performance

Meeting the Standard

Exceptional Performance

The most cost effective

8. Q&A


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8. Q&A

Thank you

Questions?

9. Further Study


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9. Further Study

Sources of InformationBowater Architectural

- website www.bowaterarchitectural.com

Regulations and Standards

- Building Regulation Documents www.planningportal.gov.uk

- British Standards Institute (BSi) www.bsi-global.co.uk

Organisations

- ALFED Aluminium Federation-www.alfed.org.uk

- The Green Organisationwww.greenappleawards.com

- Act On CO2 official government websitewww.actonco2.direct.gov.uk