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FIRE SAFETY => Fire Risk Assessments => Topic started by: Golden on January 09, 2013, 04:44:01 PM
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I've been assessing some 9-12 storey blocks where as part of a 'community energy saving solution' the RSL is fitting a community heating system consisting of a gas boiler on the roof with a pipework system of 2 x 100mm risers and various range pipes leading off into the individual flats; these pipes are all in the lobby area between the flats and the staircase. Having conducted a rudimentary test on these pipes it is found that they are thermoplastic and will burn and produce flaming droplets, burning is sustained after the heat source is removed from the sample.
The installers have put a scraping of intumescent around the pipes but clearly this isn't good enough. Has anybody else come across this situation and if so what fire stopping have you recommended - boxing in or pipe closures? Or am I simply going OTT?
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You'd normally use intumescent surface mounted pipe collars for that application. Clip them round the pipe and fasten them to the ceiling. Worrying that they're not already doing this though.
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I've been assessing some 9-12 storey blocks where as part of a 'community energy saving solution' the RSL is fitting a community heating system consisting of a gas boiler on the roof with a pipework system of 2 x 100mm risers and various range pipes leading off into the individual flats; these pipes are all in the lobby area between the flats and the staircase. Having conducted a rudimentary test on these pipes it is found that they are thermoplastic and will burn and produce flaming droplets, burning is sustained after the heat source is removed from the sample.
The installers have put a scraping of intumescent around the pipes but clearly this isn't good enough. Has anybody else come across this situation and if so what fire stopping have you recommended - boxing in or pipe closures? Or am I simply going OTT?
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Not OTT if destruction of pipe work can cause breech of compartmentation. Boxing in or Int collar, both properly done, is a solution.
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You are certainly not being over the top at all. It is critical that the level of compartmentation is maintained in high rise blocks.
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Thats not pink expanding foam I can see in the pic? Dear oh dear.
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Thanks for the responses guys - I wanted to double check as the RSL has a problem that could cost some serious money!
I think the pipe collars are the answer for the main breaches but they will have to be secured to the adjoining surfaces so it will be expensive as there are at least six block where this is happening and that concrete slab is not easy to drill! The pipes entering the flats aren't so much of a worry regarding the penetration as these go down to 20mm diameter and below but will need some fire stopping plus the flammability aspect is of concern and is under further investigation.
And yes that is a little bit of pink foam you can see!!
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On the plus side.... Should the pipe get burnt through, the water inside will act like a sprinkler system. :)
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On the plus side.... Should the pipe get burnt through, the water inside will act like a sprinkler system. :)
Does your ADB not permit pipework of low diameter penetrating compartments just to be smoke stopped? Something in the back of my brain...... Check it out.
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If there is water in the pipe it won't burn through at all. The water will absorb the heat and prevent it. Have you never seen the experiment with water being heated in paper cup or a balloon filled with water having a Bunsen flame played over it?
http://www.youtube.com/watch?v=5Y_L5n0CeiY (http://www.youtube.com/watch?v=5Y_L5n0CeiY)
http://www.youtube.com/watch?v=HK6G4-DaFv0 (http://www.youtube.com/watch?v=HK6G4-DaFv0)
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Hi Sam, my colleague and I did discuss this aspect of the heating pipes and it is one of the reasons I posted here to gather opinion. There is a worry that the heat of a fire may be enough to turn water to steam in a small section of the pipe and cause it to break? We are also assuming that there is water in the system at all times.
Do others consider that this may permit the pipes to remain unprotected?
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Interesting. I understand the compartmentation issues and the need for ensuring that smoke and fire spread can not happen. However, where is the heat source which will damage the pipe runs to such an extent that you will get heat and smoke travel?
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Does your ADB not permit pipework of low diameter penetrating compartments just to be smoke stopped? Something in the back of my brain...... Check it out.
It does but it requires the pipe to be a snug fit in the hole - the image shown looks like the proverbial p**ck in a welly. :D
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Interesting. I understand the compartmentation issues and the need for ensuring that smoke and fire spread can not happen. However, where is the heat source which will damage the pipe runs to such an extent that you will get heat and smoke travel?
Its more to do with the risk of fire in a flat for example spreading into service ducts / risers rather than the other way round.
I don't subscribe to the idea that water in pipe will mean it won't burn. I've seen those experiments that SAM refers to, but theres a difference between controlled experiments to real life conditions, and it all depends on numerous factors.
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Jokar - it works both ways for me - mainly the fire spreading from the flat into the common areas and then spreading through the common areas, secondly a fire in the common areas from combustibles that shouldn't be there (mattress/TV/Fridge all found in the common areas at the time of inspection) into the flats.
With respect to the water in the pipes and making them non-combustible in theory at least I am trying to get some clarification elsewhere but appreciate all of the contributions.
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The pipe looks more like Mapress plastic coated steel, rather than PE or PVC. It's unusual to see crimped steel fittings on plastic tube of that size, usually glued or fusion welded.
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Hi Goodsparks - a colleague of mine took some home to carry out the 'test' and there was no mention of plastic coating; if this was the case then the situation would be worse as the water in the pipe wouldn't figure significantly in reducing its combustibility.
Here's a pic of the range pipes for a bit more detail.
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if this was the case then the situation would be worse as the water in the pipe wouldn't figure significantly in reducing its combustibility
Yes it would as the heat in the plastic coating would be conducted through the metal into the water and the latent heat capacity effect would still apply. Granted there may be some scorching of the plastic as there is a delay in transferring the heat into the metal, like the sooting on the balloon in the U tube clip I posted.
Fill the pipe with water and apply a blowtorch. I would be very interested in the result.
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If you’re in England & Wales, look at Section 10 of the Approved Document B.
The water filling is irrelevant, for many reasons, not least because a) you can’t guarantee that the pipes will always be filled & b) as soon as they melt the system will drain.
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as soon as they melt the system will drain.
They won't melt it there is water in them. So they can't drain. Obviously if they are not filled with water then they will pyrolyse, scorch, char, melt or ignite; depending on what they are made from.
Can't comment on ADB.
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as soon as they melt the system will drain.
They won't melt it there is water in them. So they can't drain. Obviously if they are not filled with water then they will pyrolyse, scorch, char, melt or ignite; depending on what they are made from.
Can't comment on ADB.
I'm not sure that I agree that they wouldn't melt. The 'paper saucepan' works because the paper is thin so the heat is rapidly absorbed by the water. The polymer is likely to be a good insulator & so if subjected to direct flame it'll get above its glass transition temperature (80-odd degrees C if it's unplasticised PVC) on its exposed face. I really can't see a conventional polymer pipe keeping its integrity if directly exposed to a significant fire, no matter whether it's filled with water or not.
Having said this, I do know that sprinkler systems can utilise polymeric pipework (e.g. CPVC & Polybutylene), but I think that this is normally done either on the basis of the pipework being protected from direct flame impingement, or being protected by the activation of the sprinklers themselves (not really my area of expertise)?
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It would be an interesting test.
Perhaps someone should do it.
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Having said this, I do know that sprinkler systems can utilise polymeric pipework (e.g. CPVC & Polybutylene), but I think that this is normally done either on the basis of the pipework being protected from direct flame impingement, or being protected by the activation of the sprinklers themselves (not really my area of expertise)?
Either that or fire melts sprinkler pipe that then bursts dumping water onto fire.
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BS1285 recommends that steel or copper are used and that for dry, alternate or pre-action installations, galvanized steel should preferably be used, 9251 recommends that "Plastics and other pipes and fittings should be in accordance with a standard as recognized by the authority having jurisdiction and suitable for residential and domestic sprinkler systems and should be installed in accordance with the supplier’s instructions." but makes on mention apart from giving dimension guides on CPVC.
CPVC is a thermoplastic material that chars and will not support combustion, it is rated as self extinguishing. They are approved for wet systems only which will allow the water flow to carry away the heat once a sprinkler has actuated. There is no mention of static water in this note http://www.ribaproductselector.com/Docs/8/23138/external/COL68349.pdf
I think I'll get the full specification for the pipe and fire this one off to the passive fire protection guys to see what they say.
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Plus CPVC is a damn sight cheaper, lighter, easier and quicker to install...