This document provides information on ethylene tetrafluoroethylene (ETFE), a transparent polymer material used in construction. ETFE is lightweight, durable, and energy efficient. It is made through a process involving chemicals like fluorine and ethylene. ETFE systems are used in buildings as single or multilayer inflated cushions to form roofs or facades. Compared to glass, ETFE has advantages like flexibility, low weight, and insulation properties. It has been used successfully in notable structures like the Eden Project and Beijing National Stadium. The document discusses properties, applications, manufacturing, and case studies of ETFE.

1. ETHYLENE
TETRAFLUOROETHYLENE
A NEWBORN MEMBER IN CONSTRUCTION INDUSTRY
ARAVIND P
M.Tech – BUILDING TECHNOLOGY AND
CONSTRUCTION MANAGEMENT
IIT MADRAS

2. Water cube, Beijing
Bird’s nest, Beijing
REMEMBER ME??

3. WHAT IS ETFE?
 A transparent polymer that is used instead of glass
 Very lightweight, high daylight transmittance,
energy efficient
 High tear resistance, long life and smooth
 High flexibility, attractive, less maintenance

4. WORLD ENERGY DEMAND
• The embodied energy of building materials is one of the prime
cause

5. FATHERS OF ETFE
Dr. Stefan Lehnert Dr. Roy.J.Plunkett

6. HISTORY OF ETFE
 Originally invented by DuPont as an insulation
material for aeronautics industry
 In 1980s German mechanical engineering student
Stefan Lehnert introduced ETFE to construction
industry
 Even though some atriums during 1980s used
ETFE as covering, it became globally recognised
with the introduction of EDEN project

7. HOW IT IS MADE
 Co-polymer of ethylene and tetrafluoroethylene
Fluorspar (CaF2) Sulphuric acid (H2SO4) Fluoridic acid (HF)
Chlorine Methanol (CH2OH) Trichloromethane

8. Trichloromethane Fluoridic acid (HF) Chlorodifluoromethane(CHClF2)
Chlorodifluoromethane(CHClF2)
Pyrolysis at 700°C
Tetrafluoroethylene
Tetrafluoroethylene Ethylene
Polymerisation
Ethylene-tetrafluoroethylene

9. ETFE SYSTEMS
 ETFE panels are either created by tensioning into a single-skin
membrane or by inflating two or more layers to form cushions
 Generally cushions up to 4 foils are made, with 3-layer system being
the most common
 The air trapped between layers adds to insulation property
 Addition of more layers decreases the transparency of ETFE system

10. DOUBLE LAYER ETFE SYSTEM
These are laid as sheets with proper connections at suitable locations with
sufficient tension
SINGLE LAYER ETFE SYSTEM
This system consists of two foils with an air cushion trapped in between.
This internal pressure prestresses the foils to carry external loads

11. TRIPLE LAYER ETFE SYSTEM
1. Additional middle layer to increase the thermal performance and to decrease
transparency
2. Can be kept arched towards outer layers
3. LED lights can be incorporated
4. Can be kept fritted to control thermal performance

12. FOUR-LAYERED ETFE SYSTEM
1. A pair of foils enclosed within a double layer system
2. Three chambers of air to increase the insulation
3. More air pressure to carry more live loads
4. Least transparency

13. PHYSICAL CHARACTERISTICS
 Non-stick characteristics makes it virtually self-cleaning
 Serves a wide temperature range
 Less permeability to gas and water vapour
 Good translucency and light transmission qualities
 Can be coated to help further in control of heat and light transmission
 Excellent thermal control properties
 Excellent mechanical properties for engineering purposes in the
design of roofs or cladding systems

14. PROPERTIES OF ETFE

15. MECHANICAL PROPERTIES
o ETFE’s greater structural asset is its ductility and flexibility
o High elongation percentage helps the material to maintain tension and stability despite large
deflections
o Absorbs structural movements by conforming to changing geometries
o Dampens the effects of sudden wind gusts, reducing the design wind loads

17.  Very light weight, with thickness ranging in micro scales
 Minimal use of roof trusses or facades
 High translucency
 Transmits up to 95% of visible light and 85% of UV light
 Milky appearance and distortion of images
 More the layers, higher the insulation
 Insulating materials like rubber can be incorporated within foils
 Very low U-value
 Service temperature range from -200°C to 150°C
 Shrinks under fire and self ventilates
 Since size of material is small, drops of molten ETFE is not generally felt
 Can be used with building management system and connect with heat,
smoke, wind and rain sensors
OPTICS
WEIGHT
INSULATION
FIRE PERFORMANCE

18.  Very low embodied energy
 Long life (estimated between 50-100 years)
 Can be recycled with ease
 Low maintenance
 ETFE foils can be printed with shading patterns to control heat transmission
 ETFE can be tinted to any colour, printed with any pattern, or fitted with lights
 Poor acoustical property
SUSTAINABILITY AND ENVIRONMENTAL IMPACT
OTHER FEATURES

19. COMPARISON WITH GLASS
 ETFE is a very flexible material and cushions as long as 25m x 3m can be
easily made. Glass on the other hand is very brittle and structural dimensions
are limited
 ETFE achieves low thermal transmittance with addition of layers
 ETFE foil is transparent across the visible and UV ranges allowing about 95%
and 85% respectively. Clear glass possess a visible light transmittance of
90% and UV transmittance of about 75%. Both absorbs a fair amount of infra-
red light. Glass blocks longwave radiation but ETFE doesn’t

20.  Since the solar gain for ETFE is higher, it is preferred to have ETFE fritted or
shaded. Higher the frit density, lower the absorption of shortwave radiation
 Global warming potential and ozone depletion potential of ETFE is higher
than glass
 ETFE can take extremely high short term loading. Glass is brittle and cannot
absorb shock loads like in a bomb blast
 ETFE has low flammability and is self-extinguishing. Glass being brittle
breaks up at high temperature. ETFE releases toxic gases when burnt, but
requires very high temperature to get it burnt
 Poor acoustical properties . Glass is slightly better in this criterion

21.  Surface layer of ETFE is very smooth and it is anti-adhesive. Glass surface is
not smooth as ETFE
 ETFE panel weighs 1% of the weight of glass panel of same dimension
 Only minimal data is available on the durability criterion. Accelerated weather
test shown excellent weathering and durability qualities. Glass, being a
viscous liquid may become opaque at bottom as time pass by

22. INFLATION SYSTEM
 Foil cushions are inflated with an air hose and pump system
 Generally 200-600Pa pressure is maintained
 Central air pump system monitors the temperature, pressure and humidity of
cushions
 A single inflation unit can pressurise about 1000m2 of ETFE foils

23. AREAS OF APPLICATION
 Roof element in many stadiums, botanical/zoological gardens
 In many buildings to enhance aesthetic appeal
 Protective cover for photovoltaic (PV) cells
 PV cells are installed inside ETFE cushions to generate electricity
 Building facade integration or roof integration
 Suitable medium to house PV cells due to its visible light and UV
transmittance
INTEGRATION OF PV CELS INTO ETFE CUSHIONS

24.  Integrating PV onto the outer layers of ETFE is not generally preferred
 Primary electricity is used to control the inflation unit of ETFE
 Idea of providing motorways with PV integrated roofs
 Currently in its infancy
 Expected to meet all the energy demands of transportation field
PERMANENT MOTORWAY ROOFS

25. CASE STUDIES
 1. Geodesic Domes-EDEN Project, UK
 Consists of two grids of steel and used two layer ETFE cushions
 Structural deflections up to 20cm are easily carried
 Larger panels reduced the number of nodes to be fabricated

26.  2.Parkview Green, Beijing
 Envelope enclosing four buildings, surrounded by glass walls and ETFE roof
 Creates its own microclimate
 High thermal efficiency
 Venting of heat and smoke prevents the rapid spread of fire from building to
building
 Microclimatic envelope maintains the atrium several degrees warmer in winter
and cooler in summer

27. PHOTOGRAPHS

28. DomAquarée aquarium atrium, UK

29. Kings dale School, London

30. Allianz Arena, Germany

31. Forsyth Barr Stadium, New Zealand

32. CONCLUSION
 ETFE proves to be an efficient material to be used
in buildings. It is highly energy efficient, light weight,
strong and durable
 ETFE also suffers from disadvantages like high
initial cost, poor acoustical properties and also
compromised fire performance
 ETFE is still in its infancy and there are much more
potential to tap into

33. REFERENCES
 A. Escoffier, A. Albrecht, F.Consigny (2014), “Nice Stadium: Design of a Flat Single
Layer ETFE Roof”, International Journal of Civil, Architectural, Structural and
Construction Engineering, vol.8, pp. 298-301
 Amy Wilson (2009), “ETFE: Why this Building Material is Gaining Popularity”,
http://www.architen.com/articles/etfe-the-new-fabric-roof.html
 Architen Landrell (2011), “ Introductiong tensile fabric into your school”,
http://www.architen.com/articles/introducing-tensile-fabric-into-your-school.html
 Carol Monticelli, Andrea Campioli, Alessandra Zanelli (2009), “Environmental load of
ETFE cushions and future ways for their self-sufficient performances”, Proceedings of the
International Association for Shell and Spatial Structures (IASS) Symposium 2009,
Valencia, Spain,vol-1,pp. 754-766
 Elsa Sanaei Rad, Parisa Dorraj (2014), “Using ETFE Technology in the Field of
Optimization of Energy Consumption in Building”, Journal of Social Issues & Humanities,
vol.3, pp. 206-210
 Hannah McCann (2010), “ Material Review: One to watch”,
http://www.greenbuildingsolutions.org/Main-Menu/Home/Modern-Materials-Archive/New-
Materials-Application/Material-Review-One-to-Watch.html
 Harris Poirazis, Mikkel Kragh, Charlie Hogg (2009), “Energy Modelling if ETFE
Membranes in Building Applications”, Eleventh International IBPSA Conference,
Glasgow, Scotland
 Jianhui Hu, Wujun Chen, Bing Zhao, Hao Song (2013), “Experimental studies on
summer performance and feasibility of a BIPV/T ethylene tetrafluoroethylene (ETFE)
cushion structure system”, Energy and Buildings, vol. 69, pp. 394-406