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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: Pip on November 06, 2006, 04:59:53 PM
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Anybody have experience in actual fires with this building system?Whilst having to believe that these boards will stand up to fire (when appropriately protected by plasterboard etc) long enough to allow people to escape, I feel a little uneasy about how much 'property' protection is afforded.A client is about to build nearly 50 premises of up to 2 storeys using this system(which I know has been about for a while now) and I have a concern over internal fire spread when using polystyrene insulation material in a board that provides the structural integrity of the building.As I mention, M.O.E. is not the issue, but credibility, if the building will likely to require complete rebuild after a serious fire.
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Pip, can you give more detail on the type of panel you refer to?
Ashley
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There is a brief article in the latest 'Fire Prevention and FE Journal' about the use of these panels. Apparently there is a 'Engineered Panels in Construction' website www.epic.uk.com from which a publication "Insulated Panels and the RR(FS)O" can be down-loaded. I have not looked at this myself.
BRE's 'Fire and Risk Sciences' division has done quite a bit of work in recent years for HO, Building Regs and ODPM etc. including both visiting fires and carrying out fire tests. Their website www.bre.co.uk may be worth a look also.
A number of articles on the problems and use of these panels has appeared in the FP & FE Journal in recent years as well and if you have access to these it would be worth having a look through them
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Pip: you are joking - aren't you? Be very careful!
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It would be worth contacting the Insurer of these buildings, as they will be very interested in providing input/advice into the nature and type of combustible materials that are going to be present in the construction of these buildings.
If you were to get internal fire spread within a building of this type of construction, you might as well assume a total loss.
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The first thing to know is what type of structural insulated panels [SIPS] is proposed. The most common core materials used [polystyrene, polyurethane] behave differently particularity when it comes to fire and structural strength.
The Engineered Panels in Construction site focuses on non-structural steel faced panels used for cladding and roofing and the data is not directly relevant to SIPS.
There is over 50 years experience of SIPS construction in Europe and longer in North America. Fire has not been highlighted as a particular risk with this form of construction. In fact many so called conventional houses are safely built using large amounts combustible materials such as wood, plastic foam insulation, upvc etc.
The normal SIPS internal wall has plasterboard over the SIPS inner face which is generally 15mm OSB/3 board a very high quality material. This delivers class O surface spread of flame plus 30 minutes fire resistance as required by AD B of the Building Regulations. There are also constructions that deliver 60 minutes plus for separating and compartmentation walls. Reputable SIPS manufacturers will have tested these constructions to BS476 Part 22 with realistic axial loading.
Comparing this to a conventional internal timberframe construction, the plasterboard would be the same, there is likely to be a plastic vapour barrier under the plasterboard and there is no OSB protecting possibly combustible plastic foam insulation between the timber studs.
With regard to fire I would suggest the SIPS construction is likely to be safer.
I would suggest you ensure the SIPS come from a manufacturer with BBA approval and the recommended construction details are followed. You could also look for the LPS 2020 standard developed by BRE Certification - at the request of insurers, mortgage lenders, regulators and manufacturers.
If you use an independently certified product there is no problem getting a warranty from NHBC, Zurich etc which I suggest means they do not see extra risk.
In the event of a fire there could be advantages in a SIPS house. High level of airtighness would delay spread of smoke and high structural strenth would limit danger of progressive colapse.
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Peter,
1) He said it was to be polystyrene - the worst of the lot! There are, of course, other insulation materials that would perhaps be more suitable: PIR or Mineral Fibre for example.
2) Cladding and roofing has been much less of a problem than internal panels in real fire experiences.
3) How could you fire risk assess a building where the structure is highly combustible and then say: "it is 'normal' risk"? Therefore Pip, means of escape may well be a problem for you.
4) How can you fight a fire in such a panel? And how can B5 of the Building Regs be satisfied if firefighters refuse to enter such a building (which is a likely scenario)?
I could go on....
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Ian,
In most fire the problem is knowing the construction of a dwelling. From the outside or inside a SIPS house looks just like, timberframe, brick and block, steelframe etc.
I cannot see firefighters refusing to enter a dwelling just in case it might be SIPS construction.
In the event of a fire that penetrates 15mm of plasterboard, 15mm of OSB and is then sufficient to sustain burning of the polyurethane SIPS insulation, I would say it is more an issue of containment and not firefighting. If a fire in any type of house construction involves its combustible cavity or roof insulation the intensity is most likely to involve total write off.
When it comes to choice of building materials my philosophy is:
Most materials and components are in themselves satisfactory and most faults are due to them not being used correctly.
Similarly, most materials are fit for a purpose - but they are not always fit for the purpose for which they are used.
No product is "best" for every application. Simply that some products are superior to others in specific applications.
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Peter,
The original post does not make it clear that we are only talking about single private dwellings - but maybe we are? I have to say, my experience and knowledge comes more from the industrial/commercial use of panels although I've expected problems to arise in the domestic/residential sector with increasing use.
That being said, my experience of fires in some of the more modern timber frame dwellings gives me even more concern when someone is considering cladding those with polystyrene panels. And I certainly, therefore, would not make any assumptions as to what the fire service will or not do in these cases!
Indeed, that's another particular problem for Pip - because he won't know either until he asks (and, of course, asking a question sometimes makes people think and then give an answer you really didn't want).
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From my experience of construction sites, someone will need to keep a careful eye on the installation of these. Finished work does not always entirely accord with design plans and ad-hoc variations as unforseen issues are encountered on site can compromise the integrity of fire protection.
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One of the problems I am aware of with all panels of this type, even Rockwool or fire retardent foams, is de-lamination. This is when the adhesive that holds the face board, be it steel or plaster board, fails to adhere correctly. The fire then effects the strength of the panel resulting in collapse. Additionally, with polystyrene type sandwich panels, once the fire has entered the panel it can propagate unseen inside the panel resulting in collapse with little or no warning, hence the reason the fire service is not happy to commit fire fighters into a building using this type of panel i. e supermarkets, cold stores, food production facilities, etc.
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Guys - you keep confusing sandwich panels (steel face) with SIPS - OSB (chipboard to the rest of us) faced.
SIPS are mainly used in building single family dwellinghouses but there is a move to using them in flats.
We dont have much UK data on SIPS in real fires yet. I gues thats where the question came from.
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Thank you all for your input, was out of office for a day or so, so have only just read the replies.Basically wee brian hit the nail on the head-SIPS are not the same as the more familiar 'sandwich' panels that we have grown to love/hate where they have been used as 'cladding' on warehouses etc and resulting major lossess and trajedies.SIPs are basically slabs of Expanded Polystyrene foam sandwiched between two sheets of oriented strand board (OSB) that can be used as elements of structure ie support floors and roofs.There appears to be little published(on the internet anyway) information on these SIPS in regards to how well they will survive in a fire(Structurally).As has been pointed out by other posters, and manufacturers literature (who shout about their ability to withstand surface spread etc but silent on how well they last structuraly),when lined with plasterboard etc they are compliant with our B.Regs.My question was how well do they survive after everybody has got out ie would heat damage weaken their structure (they are able to support walls/roofs up to 2 stories) to an extent that the building would have to be demolished?The expanded polystyrene between the OSB can be treated with a fire retardent and this would be the prefered type.However through out europe both treated and untreated expanded polystyrene SIPs are used.I have read a comment that some Fire services in the US are not keen on them,where they are widely used in domestic house construction but no detail.The particular project that my client will be involved in are not 'domestic premises' but will be relatively small single story structures, and as I said,M.O.E. is not the issue.But as public money is involved, it would not look so good if, after a relatively small fire, the structural integrity may be suspect resulting in a demolish and re build rather than, as in most cases with a traditional masonary build,it probably could be repaired.Of course steel framed structures etc are possibly of a similar ilk,they have a tendency to collapse after a decent fire.I suppose it may be a trade off-a cheap and quick system that will last long enough so that everybody can get out, but after that it is expendable.
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I wonder how the improved insulation and sealing of a building constructed using these materials would contribute to the risk of more rapid flashover or possibly backdraft on opening up?
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Pip, try e-mailing the NFPA in the USA. I have had a look in my copy of NFPA 5000 2006 but cannot find anything that may be of help. I would imagine the fire departments concerns in the US are related to toxic smoke once the core is attacked by the fire. I would also have said that once the core is heated to a level where it 'shrinks away' (as it says in NFPA 5000), then it must effect its strength!
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toxic smoke Ashley!
Is there another kind?
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I'm confused Brian???? I suggest by calling something by different names is where the confusion arises.
How much information do you folks need about polystyrene?
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Well spotted Brian, you win the prize for picking me up on that!
What would you call the heavy, dense & acidic smoke produced by polystyrene rather than the smoke produced by wood etc? : - )
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heavy, dense & acidic smoke is a good start - wood smoke will kill you too. Sorry mate, I know its pedantic but people get confused.
I suspect that a SIPS built house will behave rather differently to a Sandwich Panel structure so some research is going to be a good idea. As has been suggested it wiould be interesting to know what experiences fire fighters across the pond have had.
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The Timber Research & Development Association (TRADA) say they've looked at these systems:
www.trada.co.uk/techinfo/research/293-HealthNsafety_evaluation.htm?hl=sips%2Csip
I'd be pretty sure that fire safety was part of the remit. Doesn't say what the conclusions are.
Intuitively, I'd say that you could design them so they comply with the Reg's fairly easily, but if/when the fire breaks through the linings and through/around openings total loss is probably on the cards.
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Insurers will assume 100% loss for these structures (always assuming that they can recognise them, which is a real problem in many cases). This estimation process is often a little pessimistic, but not for this construction method, IMHO.
It will be relatively easy to construct a SIP that will pass the current tests: not least because currently the wall/ceiling junctions are not tested. This is where I would expect real weakness.
The structures are likely to be deteriorating, at least in fire performance terms. throughout their lives, not only as adhesives/foams etc age, but also as a result of ordinary human occupation. These buildings have a lifespan. Would you buy one that was thirty years old?
The lifespan issue isn't necessarily a problem, provided everyone is aware. For commercial buildings, where the cost can be amortised over the lifespan, no problem. Potential owner-occupiers may wish to consider the longer term, however.
Incidentally, much of above is true for other 'Modern Methods of Construction'.
And don't get me started about MMC fire performance during the construction phase. I didn't see much comment on this forum about the fire at Colindale a few months back, which surprised me. That was scary!
All above opinions my own, of course.
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What's so suprising about a big pile of wood producing a big fire?
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Or anything combustible. Build safely how you like reduce and prevent fire risk, get people out where necessary and let the FRs adapt their offensive or defensive tactics to suit. Mind you, they may have to undertake a little more training than the stuff most firefighters and officers get at present.
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Nothing at all, Wee B.
What was surprising was the amount of damage done to other, apparently occupied, buildings that were 'officially' far enough away not to be affected by the radiated heat from what turned out to be a test crib on steroids.
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The space seperation rules are dependant on both buildings, iether side of the boundary, being compliant.
An incomplete timber frame would/did produce much more radiation than it would when complete.
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In practice PUR cored sips perform much better that Timber frame panel buildings,
Principly because, there is no oxygen to sustain combustion within the sip and there is NO CHIMNEY EFFECT with air venting up the void.
EPS Sips are nothing like as safe as PUR cored Sips,
Unscrupulas firms quote BS 476 fire resistance this is usually part 6 7 and only applies to surface spread of flame.
This is where BS gets confusing BS476 Part 21 is a toatly different fire test not only in price but application.
My firms products have been tested on three ocasions to part 21 and passed sustained loading thermal insulation.
structural integrity.
I have never seen eps panels pass this part 21 fire tset.
I have also witnessed and photographed a accidental fire started in a Sip building hotel by a careless plumber.
IT REALY DID SELF EXTINGUISH despite the attendance by half of the Cheshire fire service terning up to an auto alarm.
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www.epic.uk.com have a free download on insulated panels and the RR(FS)O in pdf for anyone interested.