Fire Resisting Furniture for within a Protected Route

[Fishy]

Bit of advice re: the treatment of timber furniture - if you ask for this (e.g. Class 1 / Class 0, C or B etc) then the tendency will be for suppliers to use an intumescent paint/varnish. 

Many of these work fine as far as fire goes, but are relatively soft and aren't at all hard-wearing - might be OK for walls/ceilings that are rarely touched but and are pretty much incompatible with constant physical contact (i.e. being sat on).  The impregnation treatments are much better for this type of application, but these have to be applied using an off-site process & compatibility with whatever the final finish will be needs to be checked.

[Messy]

Fishy - I agree in that I am not happy with treating existing furniture that is bound to be knocked and chipped over the years.

Anthony - No, these landings do not form refuges or any such useful purpose. One staircase has landings of around 20m x 8m - a combined area of 1,600m2 of largely unused space in one staircase alone and in an expensive city centre location. You can see why there's a demand to utilise them for something

I have stuck to my guns and recommended completely non combustible furniture only, supported by a policy of no waste bins and regular housekeeping inspections. I have even hit the interweb and supplied examples of adequate furniture. That's it, job done - other than batting away any resistance that is bound to follow

Many thanks to all for your assistance

[AnthonyB]

I do know of a similar situation where the answer was in the form of a fire curtain operated by local detection - if the fire is in the furnished area it get's isolated from the stair by the curtain (floor to ceiling type used, more akin to a shutter). Whilst costly the client preferred the cost than more traditional separation.

[Messy]

The curtain idea would most certainly be feasible in this case. But I have been told in no uncertain terms that this has all got to be done on the hurry up and at as close to nil cost as possible. So  a suggestion of installing of 20 x of these rather expensive fire curtains would not be welcomed!!! However, its a useful point to put in as an option at the end of the report in order that funds be made available in future budgets.

Thanks

[kurnal]

Personally I struggle to see what a curtain would achieve. Unlike a permanent structure it would not provide any protection until after a fire was confirmed, detected and the curtain descended. By this time that particular staircase would almost certainly be untenable. Curtains of this size are also very expensive and smoke control and integrity issues arise at the junctions and corners.

[Phoenix]

I understand all the concerns expressed but do not think that there is much of a problem here.

You don't treat timber furniture with intumescent paint but you can use timber that can be categorised as being a material of limited combustibility (i.e. a relatively dense hardwood, see ADB or other sources). 

Guidance allows a smallish reception to be situated in a staircase when the building has more than one staircase, so provided that the furniture presents no greater fire loading than such a reception area then we remain, in essence, code compliant.

If you wanted to put furniture in two or more of the staircases then I really cannot see the problem in a well managed building.  If there is a fire, it will only involve one staircase, it's not going to leap from staircase to staircase.  The risk of arson would need to be considered here.

I understand that the building is full to capacity and that all the stairs are required for evacuation.  I also understand that if the fire is in one of the staircases then there are a restricted number of escape routes and occupants will take longer to clear the floors and reach a place of 'relative safety'.  But this is not important because the fire is enclosed in a staircase and people have at least half an hour to clear the floors in an environment protected from the fire, longer if there are lobbies, longer still if it is a firefighting stair.  The floors themselves are places of 'relative safety' if the fire is in a staircase.  Confidence in the compartmentation is required for this argument to be valid.  Also, of course, the building must not have pressure differential systems installed.

If the staircase has disabled refuges in it then don't use them, use other ones.

If the relevant staircase is a firefighting staircase then this makes little difference.

I am slightly concerned that people can pass through some of the storey exits into the staircases and have the door lock shut behind them.  This is not a good idea in any building and has implications for means of escape and for firefighting.  I deal with many large multi-tenanted buildings and rarely come up against objections to having all the doors unlock on the alarm.  There should be even less reason to object if the building is all occupied by the same organisation.  If there are good reasons to have doors remain locked then specific solutions should be put in place to deal with each case.

Care should be taken to ensure that the furniture does not obstruct escape routes and that other more combustible items do not creep in.  A daily check should be sufficient.

Yes, the building has to be well managed, yes the locking door issue should be sorted out and yes, we would really prefer it if the furniture didn't catch fire so it should pass the 5852 cigarette and match ignition tests and generally comply with the furniture, etc, regs but otherwise I see no problem.

Finally, you won't be setting a precedent by allowing furniture in the stairs, there are thousands of safe buildings that already have small amounts of controlled fire loading in staircases.

[Messy]

Guidance allows a smallish reception to be situated in a staircase when the building has more than one staircase, so provided that the furniture presents no greater fire loading than such a reception area then we remain, in essence, code compliant.

...............

Finally, you won't be setting a precedent by allowing furniture in the stairs, there are thousands of safe buildings that already have small amounts of controlled fire loading in staircases.

Phoenix

Thank you for your post as its this type of scrutiny I was after to check I hadn't missed anything and that I wasn't being OTT. In fact I like your 'make it happen' approach as this is how I try to operate, which is why I am struggling here as I simply cannot give a green light to this proposal.

With reference to the doors locking behind evacuees, the RP does have systems in place which make this necessary security measure suitable from a MOE perspective

It is the aggregate staircase fire loadings  + the high occupancy which I am concerned about. I am not content with proposing strategy which permits significant amounts of combustibles in staircases and  accepts the possibility (however low) of thousands of people queuing up to 30 minutes in a protected routes where one staircase is impassable.

The  RP had placed 4 x sofas on a landing before I discovered it with a plan for 2 more. The proposal was this would be repeated on all floors. This would have meant this particular staircase would have had 54 x sofas and some tables in it!!!! Perhaps more fire loading than an average DFS furniture shop and a little more than a desk, a couple of sofas and a PC that any reception may involve. The second staircase landings are somewhat smaller, but would still have had 36 more sofas spread across the 10 floors.

So all I am saying is lets have these spaces, but use non combustible furniture.

[Fishy]

I understand all the concerns expressed but do not think that there is much of a problem here.

You don't treat timber furniture with intumescent paint but you can use timber that can be categorised as being a material of limited combustibility (i.e. a relatively dense hardwood, see ADB or other sources).  

Guidance allows a smallish reception to be situated in a staircase when the building has more than one staircase, so provided that the furniture presents no greater fire loading than such a reception area then we remain, in essence, code compliant.

If you wanted to put furniture in two or more of the staircases then I really cannot see the problem in a well managed building.  If there is a fire, it will only involve one staircase, it's not going to leap from staircase to staircase.  The risk of arson would need to be considered here.

I understand that the building is full to capacity and that all the stairs are required for evacuation.  I also understand that if the fire is in one of the staircases then there are a restricted number of escape routes and occupants will take longer to clear the floors and reach a place of 'relative safety'.  But this is not important because the fire is enclosed in a staircase and people have at least half an hour to clear the floors in an environment protected from the fire, longer if there are lobbies, longer still if it is a firefighting stair.  The floors themselves are places of 'relative safety' if the fire is in a staircase.  Confidence in the compartmentation is required for this argument to be valid.  Also, of course, the building must not have pressure differential systems installed.

If the staircase has disabled refuges in it then don't use them, use other ones.

If the relevant staircase is a firefighting staircase then this makes little difference.

I am slightly concerned that people can pass through some of the storey exits into the staircases and have the door lock shut behind them.  This is not a good idea in any building and has implications for means of escape and for firefighting.  I deal with many large multi-tenanted buildings and rarely come up against objections to having all the doors unlock on the alarm.  There should be even less reason to object if the building is all occupied by the same organisation.  If there are good reasons to have doors remain locked then specific solutions should be put in place to deal with each case.

Care should be taken to ensure that the furniture does not obstruct escape routes and that other more combustible items do not creep in.  A daily check should be sufficient.

Yes, the building has to be well managed, yes the locking door issue should be sorted out and yes, we would really prefer it if the furniture didn't catch fire so it should pass the 5852 cigarette and match ignition tests and generally comply with the furniture, etc, regs but otherwise I see no problem.

Finally, you won't be setting a precedent by allowing furniture in the stairs, there are thousands of safe buildings that already have small amounts of controlled fire loading in staircases.

The key issue, though, is you're assuming that everyone who needs to escape knows there's a fire in that staircase & no-one uses it.  I'm personally not convinced that's a safe assumption.  You would potentially be compromising the Basis of Design for the entire premises.  We don't design buildings with too many protected staircases - we put in just enough and no more.

Also:

There is no such thing as a timber that is a "material of limited combustibility" and there is no treatment that would allow any timber to meet that performance (as defined in the guidance to the Building Reg's).  Density is not necessarily a good indicator of reaction-to-fire performance (for example, Ash is relatively dense but it has that name for a reason)!

You should never equate fire resistance ratings with the length of time you'll be 'safe' from a fire - they are simply a means of ranking fire resistance performance and the length of time something may stand up to a 'real' fire will in all likelihood be completely different (longer or shorter).

If you compromised a fire-fighting staircase / lobby by placing furniture in it then (if you're in England & Wales) you might arguably be committing an offence under Regulation 38 (Maintenance of measures provided for protection of fire-fighters).

At the end of the day, though it might be convenient it is rarely (if ever) necessary to install combustible items in staircases - so the first port-of-call for any risk assessment - eliminate the hazard - ought to be applied in most cases.

[Phoenix]

Yes, ok about the timber, Fishy.  But that's not the issue here. You state that the key issue is that everyone has to know there is a fire in the staircase.  I don't think anyone would have to be in a staircase for long, if at all, to detect that there is a fire, or at least smoke, in it.  In which case they can leave the staircase and use another route.  This is the principle that is accepted when we allow reception desks in staircases so it cannot be argued that this is an unacceptable principle.  This is why I was concerned about the locking doors.

I find it hard to imagine the RP being prosecuted for contravening Article 38 but you're right that this should be considered.  However, I do know of a few new fire engineered buildings where firefighting access to upper floors is via routes that contain some fire loadings.  The thinking is that if the fire is not in the firefighting access route then the fire loading makes no difference and if the fire is in the firefighting access route then they can either use one of the alternative routes (if distances permit) or simply tackle the fire directly from within the space.  I agree that there could be firefighting issues if the nearest alternative firefighting staircase is far removed from the one with the fire and if the fire is higher than about the 6th floor.

Messy, if the sofas are reasonably spread out it could be reasonable to suppose that a fire would be slow to spread from one landing to the next if, indeed, this is even deemed possible.  When we sprinkler a building we assume that, in the event of a fire, only a relatively small proportion of the many hundreds of sprinkler heads in the building actuate because the sprinklers control the size of the fire.  Similarly here, if you are satisfied that the space separation between sofas on adjacent landings is sufficient to control fire spread from one level to the next then we don't have to be concerned about the sheer number of sofas in the staircase, we only have to be concerned about the number that could be expected to be involved in the largest reasonably foreseeable fire.  The desire to restrict fire spread is why, if sofas were allowed, there would have to be regular checks, at least daily, to ensure that other combustibles are not permitted (maybe one or two magazines).

[Fishy]

Yes, ok about the timber, Fishy.  But that's not the issue here. You state that the key issue is that everyone has to know there is a fire in the staircase.  I don't think anyone would have to be in a staircase for long, if at all, to detect that there is a fire, or at least smoke, in it.  In which case they can leave the staircase and use another route.  This is the principle that is accepted when we allow reception desks in staircases so it cannot be argued that this is an unacceptable principle.  This is why I was concerned about the locking doors.

I find it hard to imagine the RP being prosecuted for contravening Article 38 but you're right that this should be considered.  However, I do know of a few new fire engineered buildings where firefighting access to upper floors is via routes that contain some fire loadings.  The thinking is that if the fire is not in the firefighting access route then the fire loading makes no difference and if the fire is in the firefighting access route then they can either use one of the alternative routes (if distances permit) or simply tackle the fire directly from within the space.  I agree that there could be firefighting issues if the nearest alternative firefighting staircase is far removed from the one with the fire and if the fire is higher than about the 6th floor.

Messy, if the sofas are reasonably spread out it could be reasonable to suppose that a fire would be slow to spread from one landing to the next if, indeed, this is even deemed possible.  When we sprinkler a building we assume that, in the event of a fire, only a relatively small proportion of the many hundreds of sprinkler heads in the building actuate because the sprinklers control the size of the fire.  Similarly here, if you are satisfied that the space separation between sofas on adjacent landings is sufficient to control fire spread from one level to the next then we don't have to be concerned about the sheer number of sofas in the staircase, we only have to be concerned about the number that could be expected to be involved in the largest reasonably foreseeable fire.  The desire to restrict fire spread is why, if sofas were allowed, there would have to be regular checks, at least daily, to ensure that other combustibles are not permitted (maybe one or two magazines).

I have to say we'll have to agree to disagree... how do they get out of the staircase when everyone else is trying to get in (which is what all the fire exit signs are telling them to do)? 

As I said, when we design buildings we spend good money (sometimes a lot of money) constructing  these routes to be protected and sterile, as recommended in the various standards, so why compromise them unless it's absolutely necessary (which it rarely - if ever -is)?   You can always come up with scenarios whereby if everything goes right & a fire event is perfectly managed then some of this stuff might not be absolutely necessary, but the standards don't assume everything goes right - they assume it doesn't & build in a certain amount of resilience to cope with the unforeseen. I'm not normally brave enough to assume that in the rare event of a large fire everything will be perfectly managed....

...and so far as the combustible stuff in the fire-fighting routes is concerned... again it relies upon everything going perfectly & the Brigade knowing exactly where the fire is before they commit.  I wouldn't have written that fire strategy with a clear conscience!

[Messy]

  We don't design buildings with too many protected staircases - we put in just enough and no more.

Is this really true? When determining the occupancy of a building, one method is to discount a staircase. So in effect, that becomes a 'spare' staircase which is surplus to requirements in terms of a MOE strategy. It could be lost due to fire and there would be sufficient capacity in the remaining stairs

The building I have been referring has a lobbied staircase situation on all cores. Therefore no staircase has been discounted when the building's capacity has been determined and it will be running at max capacity soon. Therefore all staircases will be needed to satisfactorily evacuate those present - Thus my rationale for maintaining 'sterile' environments in the protected MOEs

[kurnal]

Is the capacity of each staircase limited by the staircase width  (ie table 7 ADB calcs) or by the doors? Table 7 is based on a 2.5 minute evavuation time, in some non combustible buildings it might be appropriate to consider 3 minutes as a reasonable time?

If all staircases are used to full capacity without discounting, then clearly if a staircase is unavailable queues are inevitably going to arise at storey exits leading to other staircases, starting on the fire floors and those above. Simple arithmetic, together with a judgement on the quality of fire doors and screens  will indicate if this is likely to be a problem during the evacuation phase. I guess that with 10 staircases and reasonable fire safety management by fire wardens queues may not place persons at risk.
Personlly I never compromise on firefighting shafts. I see the "alternatives"  argument presented by Phoenix so often as being justified by fire engineers without a fire fighting background. If it were so simple as maintaining  alternative routes all we would need is compartmentation. Trouble is firefighting is a dynamic event and often the fire does not behave as expected,  other weaknesses or failings in the building lead to rapid or unexpected fire and smoke spread and this requires often a review of tactics, including evacuation strategies for relevant persons.

[Phoenix]

I respect all your views and I agree that fire safety is about providing layers of safety to guard against degradation of safety features.  But, without knowing the building involved here, I still consider that there is scope to examine the alteratives without rejecting any approach just because the book says so.  I know, you'll jump on that comment and say it's not 'just because the book says so', you've thought this through logically and objectively - but I would disagree because I can still see gaps in the argument for rejecting the furniture without closer analysis.

We cannot closely analyse this matter because we, except messy, haven't inspected the building.  In view of the lack of direct information in this case I will agree to disagree.

how do they get out of the staircase when everyone else is trying to get in (which is what all the fire exit signs are telling them to do)? 

There is very little probability that the pressure of people thrusting forward out of their safe office environment that contains no threat or signs of fire into a staircase that contains, at least, smoke and possibly other signs of fire will be so great that people will not be able to turn round and tell others not to go that way.  Remember, in their safe office environment no is going to be panicing, no one will be highly motivated to evacuate and many will be slow to respond, whereas any person who happens to be in the staircase will be reasonably well motivated to leave the staircase.  If this were not the case then how could we accept reception desks in staircases?

[Fishy]

  We don't design buildings with too many protected staircases - we put in just enough and no more.

Is this really true? When determining the occupancy of a building, one method is to discount a staircase. So in effect, that becomes a 'spare' staircase which is surplus to requirements in terms of a MOE strategy. It could be lost due to fire and there would be sufficient capacity in the remaining stairs

The building I have been referring has a lobbied staircase situation on all cores. Therefore no staircase has been discounted when the building's capacity has been determined and it will be running at max capacity soon. Therefore all staircases will be needed to satisfactorily evacuate those present - Thus my rationale for maintaining 'sterile' environments in the protected MOEs

I agree with your analysis is correct - but I'd have to say that I don't think 'spare' is the right term - discounting staircases gives you the resilience in your evacuation strategy that I was promoting earlier. 

If the staircases in this building are lobbied then that strongly indicates that they were all considered necessary when the building was designed - which (in my view) makes your judgement to recommend they be kept sterile spot on.

[Fishy]

...Personally I never compromise on firefighting shafts. I see the "alternatives"  argument presented by Phoenix so often as being justified by fire engineers without a fire fighting background. If it were so simple as maintaining  alternative routes all we would need is compartmentation. Trouble is firefighting is a dynamic event and often the fire does not behave as expected,  other weaknesses or failings in the building lead to rapid or unexpected fire and smoke spread and this requires often a review of tactics, including evacuation strategies for relevant persons.

Well put.  I sometimes have to remind my younger colleagues of the inconvenient truth that fires don't read fire strategies...