First of all a big thank you to those who attended my webinar last Friday on the above subject. If you missed it or would like to watch it again a recorded version is available here. Many questions were asked after the presentation and I decided to post the most interesting ones up here for everybody’s benefit.
Before I do, I confirm that the presentation I made has been CPD approved and if that you watch either the entire recorded or live version, you may request that we send you a CPD attendance certificate.
Q: How can a glass panel or gypsum board be certified as a smoke barrier, as they are very often used in these kinds of applications?
A: Since CE marking has not been essential in the UK up to now, not many, if any, of these materials have been certified to EN 12101-1. In general, the authorities accept this, e.g. if the material is fire-rated glazing. The fact that Construction Products Regulation states that CE marking for these products is to be mandatory and that a smoke curtain should be tested to EN 12101-1 means that this will be a grey area unless manufacturers of these products get them tested and approved.
Q: With regards to the emergency access switch, how do we determine the insulation period?
A: In terms of using the radiation measurement, in BS 8524 there is a simple table for simple dwellings, but for more complex buildings a competent fire engineer or similar expert should be involved to understand what is written there.
Q: How can a curtain really substitute a fire door? The issue is psychological: the advantage of fire door is that it opens and closes using a spring, and in the case of a fire anyone will see that the exit is generally blocked, so they are used to pushing open a door.
A: Yes, this could lead to confusion if a fire curtain is used across an escape route. This makes it essential that there is an egress switch and that people are aware that it is there. The main advantage of a fire curtain or barrier in this application is that it is hidden away when not used. It is a free choice.
Q: What is the price difference between a fire door and a fire curtain? Anyway I believe that that a fire curtain is much more expensive than doors, so why use a curtain, which may lead to provoking confusion, since people only see a blocked means of escape rather than an opening door?
A: I cannot confirm that the price difference is big or not. The building owner / designer has to make a choice - do they want the device to be hidden or not? In any case, at the time when the majority are escaping, it is unlikely that the curtain will be lowered.
Q: Most uses of fire curtains are essentially fire engineered solutions, but often suggested by architects without FE supporting the design. Would manufacturers such as Colt check the correct spec or would that be left solely to building control?
A: Any reputable manufacturer of fire curtains should look at the uses of the curtain and make sure that they are happy for their curtain to be used in that application. Obviously building control should be involved as well. Colt would not want to provide a curtain without knowing where it was to be installed, what it is going to do or understanding if it is indeed suitable for the application.
Q: A fire service access button also allows a barrier to rise slightly, preventing flashover.
A: Indeed this would allow some air into the space and this hopefully would help to prevent flashover.
Q: Should a smoke or fire curtain descending across a means of escape move on heat detection only?
A: Generally a curtain will be controlled by a heat or smoke detector local to the curtain. If a fire curtain is installed across a means of escape, then it is indeed important that it is controlled by local detection rather than from a general detection over a widespread zone, because you don't want the curtain to drop any earlier than it really needs to. If it is a smoke curtain, then it is not so critical, as it will be above people's heads.
Q: The use of fire curtains as a replacement for fire doors is fairly common but is there a problem when the fire service arrive? Gaining access to the area by raising the curtain and starting fire fighting activities. Firstly how do you keep the curtain open? You mentioned a button which had to be held in to raise the curtain, so do you expect the fire service to deploy a fireman to do this job? Secondly if the fire service pull back the curtain would take time to close leaving the fire men exposed to the fire for a longer period than closing a fire door.
A: If you are looking at gaining access into a building well away from the actual location of the fire, then obviously the fireman's switch will provide perfectly adequate access. A hose can be run under the bottom bar, even if it holds the curtain open a bit. In the actual location of the fire, if the fire curtain is between where the fireman wants to stand and the fire, then the remedy would be either to keep the button pressed, which is not ideal, to put the hose through an overlap or to cut away the fire curtain locally. This is an issue for the fire service to consider and for those designing the fire strategy of the building - all of this needs careful consideration at the design stage.
Q: Have you got any fire curtains in situ in London that would be good to see?
A: Yes, Colt has installed fire curtains across the UK, so please talk with our sales people to obtain a reference list.
Paul is a Technical Director for Colt, experienced in smoke control, HVAC, solar shading and louvre systems.