ETFE cushions have become increasingly popular as a cost effective alternative to glass in rooflights and facades. They offer many benefits over glass; they are very light, so require much reduced structural support and they are able to absorb large deflections without fracturing. They have been used successfully in numerous projects – among them the very distinctive Biomes of the Eden Project, in Cornwall.
Why would they be any good for smoke control?
It has been argued that because ETFE can melt, the cushions are able to ‘self vent’ in the event of fire, ‘shrinking back from flames to allow the fire to vent to atmosphere,’ eliminating the need for smoke control.
Why is it not a good idea?
There are some very real concerns about using ‘low-melt’ panels for smoke control. First of all, the claim that a rooflight will ‘self vent’ means that there will be no design input into the arrangement of smoke control measures in the building. This could leave the responsibility for smoke control design to a contractor who may not have the necessary expertise.
The second concern is whether the ETFE panels, with a melting point in excess of 200oC have the ability to ventilate the smoke in the necessary timeframe and quantities.
ETFE is no substitute for a smoke control system
When considering ETFE as an alternative to glass in a rooflight, its ability to melt is not a substitute for the installation of a properly designed automatic smoke control system. And it doesn’t negate the need for a fire engineer or smoke control specialist to competently design a complete system that will take into account all aspects of the building and its usage.
Designing a smoke control system when using ETFE cushions
There are a number of important considerations about effective smoke control when designing a building with ETFE rooflights. You will find useful advice in our whitepaper, which you can download here.
Conor Logan is a Technical Manager of Colt UK, Smoke and Climate Control Division. Conor is also Chairman of the Smoke Control Association.