Are wooden buildings not fireproofed?
Discussion
Mods, please don't put in a Youtube thread, I'm just using the link to illustrate a point! 
So, whilst wasting evenings looking at Youtube I've noticed something that surprises me, it seems that timber buildings are really rather popular abroad, particularly US, Canada etc. I guess this makes sense due to cheapness and availability of the wood.
When they catch fire however, they seem to burn with a speed and ferocity that makes an average UK brick built house seem significantly more sturdy. I've watched quite a few videos and in almost all cases, the house looks like a borderline total loss, and often they end up taking the neighbour's house with them too.
This video illustrates my point best, 400 apartments arranged over several storeys, totally obliterated by a small fire in one flat. How in god's name are such weak building standards allowed?
https://youtu.be/yQJMJ6E-OYY?t=4m23s
Before anyone points it out, I know there have been examples of high rise fires spreading in the UK, but generally, the brick and concrete buildings seem a LOT more robust most of the time. I'm pleased my flat is in a nice solid concrete block...
So, whilst wasting evenings looking at Youtube I've noticed something that surprises me, it seems that timber buildings are really rather popular abroad, particularly US, Canada etc. I guess this makes sense due to cheapness and availability of the wood.
When they catch fire however, they seem to burn with a speed and ferocity that makes an average UK brick built house seem significantly more sturdy. I've watched quite a few videos and in almost all cases, the house looks like a borderline total loss, and often they end up taking the neighbour's house with them too.
This video illustrates my point best, 400 apartments arranged over several storeys, totally obliterated by a small fire in one flat. How in god's name are such weak building standards allowed?
https://youtu.be/yQJMJ6E-OYY?t=4m23s
Before anyone points it out, I know there have been examples of high rise fires spreading in the UK, but generally, the brick and concrete buildings seem a LOT more robust most of the time. I'm pleased my flat is in a nice solid concrete block...
We lost our wooden house to fire 30 years ago. Modern ones are much, much more advanced.
http://www.rethinkwood.com/wood-meets-code/fire
http://www.rethinkwood.com/wood-meets-code/fire
In the UK and elsewhere with half-reasonable building codes, once the timber-framed building is finished, then spread of fire is pretty limited by the way the frame is enclosed in fire-resisting material and so a lot of risk goes away. Multi-storey timber framed buildings are actually most vulnerable during construction as a result, while framing remains exposed, and there have been a couple of high-profile UK constrcution site fires in the last 3-4 years which are still under review from a design-standards perspective for teh temporary condition.
That said - a serious point often missed - the function of fire compartmentation is not ever to save the building: it is to buy time to get the occupants out safely. Once that's done, the fabric can be a total loss* - that's an insurance problem, not a life-safety one. Timber buildings do not have a significant problem on the life-safety front, in fact, in certain regards, can perform very, very well in that regard, becasue the behaviour is very predictable (known charring rates etc make this so). If timber frames didn't behave well - they simply would not be built, because no insurer would cover this design route (i.e. back the necessary construction financing & post-occupation risks)
That said - a serious point often missed - the function of fire compartmentation is not ever to save the building: it is to buy time to get the occupants out safely. Once that's done, the fabric can be a total loss* - that's an insurance problem, not a life-safety one. Timber buildings do not have a significant problem on the life-safety front, in fact, in certain regards, can perform very, very well in that regard, becasue the behaviour is very predictable (known charring rates etc make this so). If timber frames didn't behave well - they simply would not be built, because no insurer would cover this design route (i.e. back the necessary construction financing & post-occupation risks)
- NB - this is entirely true of wholly-masonry buildings too - e.g. concrete frames tend to be inherently resistant to fire, and of course present no fire load themselves - but having survived a fire, the building will often be razed simply because it cannot be guaranteed to perform properly structurally to the original design loading, let alone, resist any further fire load again in future: masonry calcines, loses strength etc. Steel frames - definitely forget it, after a fire the affected area will be dismantled.
Edited by Huff on Thursday 23 July 22:02
Kentish said:
Ouch!It seems to me though that an apartment building shouldn't need razing to the ground following a small fire in an airing cupboard, who signs this stuff off!? Surely they should burn slowly enough that the fire can be contained and extinguished before this happens?
Can't agree to a previous post above where they say fire compartmentation isn't ever to save property as I spent a significant part of my career doing just that. Fire department and building regs have their strategies and input but they are just interested in preserving life. And as such often want half hour rated escape routes Insurers want a higher degree of fire separation in many situations where there is a lot of property at risk. Many will want 2 hour fire break walls/floors as a minimum others go for 4 hours. I've seen 6 hour rated compartments where there are serious amounts of money at risk in terms of actual physical and consequential loss. (I've even seen a 4 hour rated wall between a superstore and their warehouse breached by fire in around 40 minutes such was the fire load in the warehouse which I believe was rammed to capacity and beyond by very combustible Xmas stock)
OP you think your concrete building is safe? I found many blocks of flats where the fire stopping had not been completed from day one and it cost them many thousands to have it put in retrospectively. Even found one landmark building probably with a rebuild cost today of £100M which had stood for 40 years where this hadn't been done. That one cost an awful lot to put right. You could look into a shaft and look up and down many floors, a fire in there would spread rapidly causing a fire to break out on multiple floors.
I'd suggest you check your service risers (if you are lucky there just one but maybe several) where utilities etc pass up through the the building, if you can see there is no preferably concrete between the floors you may have a problem. I'd be interested to hear what you find.
OP you think your concrete building is safe? I found many blocks of flats where the fire stopping had not been completed from day one and it cost them many thousands to have it put in retrospectively. Even found one landmark building probably with a rebuild cost today of £100M which had stood for 40 years where this hadn't been done. That one cost an awful lot to put right. You could look into a shaft and look up and down many floors, a fire in there would spread rapidly causing a fire to break out on multiple floors.
I'd suggest you check your service risers (if you are lucky there just one but maybe several) where utilities etc pass up through the the building, if you can see there is no preferably concrete between the floors you may have a problem. I'd be interested to hear what you find.
Blue Oval84 said:
Ouch!
It seems to me though that an apartment building shouldn't need razing to the ground following a small fire in an airing cupboard, who signs this stuff off!? Surely they should burn slowly enough that the fire can be contained and extinguished before this happens?
Multi story timber frame relies on good detailing to fire stop penetrations between protected areas. Often difficult as this can be some of the last work to be carried out on-site as services need to pass through these penetrations. It seems to me though that an apartment building shouldn't need razing to the ground following a small fire in an airing cupboard, who signs this stuff off!? Surely they should burn slowly enough that the fire can be contained and extinguished before this happens?
This will have been signed off by a commercial company acting as an Approved Inspector for Building Regulations purposes. Commercial and time pressures at the end of major projects can often mean that fire stopping is not fully checked, but the building is 'signed off' anyway.
The Regulations are entirely about life safety, so the only objective is to keep the Building standing until all occupants can be evacuated (usually 60 or 90 mins). After that, the design can allow it collapse.
elanfan said:
I'd suggest you check your service risers (if you are lucky there just one but maybe several) where utilities etc pass up through the the building, if you can see there is no preferably concrete between the floors you may have a problem. I'd be interested to hear what you find.
Interesting point, I'll have a look in the cupboard soon and report back. Our building is unusual in that, apparently, the stairwells used to be external (they're now enclosed in glass). The service riser is located within this stairwell, and separate from the "block" where the flats are.However, in theory if the service cupboard ever caught fire (how much of a problem would the burning mains cables, Virgin cable and electricity meters be?) and it spread, then the fire would render escape from the flats impossible. I live on the third floor and there is only the one enclosed stairwell leading from my flat to the ground. I suppose even if it didn't spread then smoke alone could be enough to trap me and my neighbours in the flat...
elanfan said:
Can't agree to a previous post above where they say fire compartmentation isn't ever to save property as I spent a significant part of my career doing just that. Fire department and building regs have their strategies and input but they are just interested in preserving life. And as such often want half hour rated escape routes Insurers want a higher degree of fire separation in many situations where there is a lot of property at risk. Many will want 2 hour fire break walls/floors as a minimum others go for 4 hours. I've seen 6 hour rated compartments where there are serious amounts of money at risk in terms of actual physical and consequential loss. (I've even seen a 4 hour rated wall between a superstore and their warehouse breached by fire in around 40 minutes such was the fire load in the warehouse which I believe was rammed to capacity and beyond by very combustible Xmas stock
Good clarification, well made. I was restricting myself to the kinds of buildings timber frames are most-commonly used for.The points made also about the sensitivity to fire-stopping is a material consideration; there always remains a workmanship risk, even if the design is deliberately simplified to minimise the requirement and ease of installation/inspection.
Blue Oval84 said:
Interesting point, I'll have a look in the cupboard soon and report back. Our building is unusual in that, apparently, the stairwells used to be external (they're now enclosed in glass). The service riser is located within this stairwell, and separate from the "block" where the flats are.
However, in theory if the service cupboard ever caught fire (how much of a problem would the burning mains cables, Virgin cable and electricity meters be?) and it spread, then the fire would render escape from the flats impossible. I live on the third floor and there is only the one enclosed stairwell leading from my flat to the ground. I suppose even if it didn't spread then smoke alone could be enough to trap me and my neighbours in the flat...
The stairwell should be a sterile area with nothing combustible within (so don't allow anyone to store their crap there). If you have an automatic fire alarm ensure they've extended it into the new enclosed areas. The toxins and corrosives given off by plastic covered wiring, possibly plastic pipes could kill you. The riser should ideally have a fire rated door on it with an intumescent seal a minimum of half hour though I'd prefer an hour. Also a smoke detector in the risers wouldn't hurt.However, in theory if the service cupboard ever caught fire (how much of a problem would the burning mains cables, Virgin cable and electricity meters be?) and it spread, then the fire would render escape from the flats impossible. I live on the third floor and there is only the one enclosed stairwell leading from my flat to the ground. I suppose even if it didn't spread then smoke alone could be enough to trap me and my neighbours in the flat...
Get yourself one if those roll up ladders you can throw out a window (don't forget to bolt it to the wall first).
Would like to hear what you find.
Troubleatmill said:
Way back in times of old....
They used very thick oak beams etc.
Because.... if it caught fire.... the outside seared... and protected the rest of the wood.
The structure would be sound.
I don't believe that was the main reason for using the timber frame. Just serendipitous.They used very thick oak beams etc.
Because.... if it caught fire.... the outside seared... and protected the rest of the wood.
The structure would be sound.
You're quite right about the heavy beams, though. The burnt outer forms a sacrificial layer. Those oak beams would last longer than a steel RSJ. Once steels get hot they lose their strength very rapidly.
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