cross corridor doors in sprinklered hotel

[TickityBoo]

Are cross corridor smoke control doors really necessary in a sprinklered hotel? While I would expect subdivision of long corridors in an unsprinklered hotel (particularly if the bedroom doors onto the corridor are without strips and seals), in a sprinklered building the size of fire should be severely limited and hence the volume of smoke generated is likely to be much less.   L2 detection is a given btw (HDs in bedrooms).

[kurnal]

The cross corridor doors are there to ensure a fire cannot affect the routes to more than one storey exit. The sprinkler system should ensure that the fire is suppressed to an extent that it is unlikely to affect any storey exits.So you proposal seems sound to me- but consider contingencies should the sprinkler system be down for some reason.

[jokar]

In that case a fire can start in an escape route and produce large volumes of smoke prior to any heat detection going off and block the escape routes   I beleive there was a fire in a hotel which started in the trolley used by the cleaning staff.  Without adequate corridor protection the escape routes, more than one will always be compromised.

[nearlythere]

In that case a fire can start in an escape route and produce large volumes of smoke prior to any heat detection going off and block the escape routes   I beleive there was a fire in a hotel which started in the trolley used by the cleaning staff.  Without adequate corridor protection the escape routes, more than one will always be compromised.

How would a corridor door have helped in this situation Jokar? What if the trolley had gone on fire within a seperated area of the corridor? The control measure should be to determinate the risk posed by a cleaners trolley and remove or significantly reduce the risk to a tolerable level.

[jokar]

Simple you can not stop a fire starting and whilst eleimination of the ignition sources would be the best risk reduction method, a fire could occur.  The idea of the cross corridor doors is in part to separate the escape routes so that when people leave they still have a choice.  I agree if you walk out into a smoke filled corridor there is still smoke there but you may not have to walk to far to get the other side of the cross corridor doors.  The sprinkler system will do nothing to alleviate this situation.

[Dragonmaster]

Assuming the fire produces smoke before the sprinkler system operates, the sprinklers themselves are more likely to increase the smoke volume (albeit not a dense), so with out smoke stop doors in the corridor, both alternatives have to be approached through smoke.

[TickityBoo]

If the fire starts in a bedroom, its behind a 30min s/c FD and the HD/sprinkler head in the bedroom will not only raise the alarm but extinguish, or at least control, the fire should it take hold and grow.  HDs in bedrooms are to raise the alarm incase cold smoke/pyrolysis products are not buoyant enough to activate the optical SDs in the corridor. Let's not go into the argument of alerting the person in the room of origin.

As the corridor is a protected zone, there should not be any combustible storage/obstructions.  But assuming sods law and a fire does take hold in the corridor, the optical SDs should raise the alarm before the sprinklers go off - giving early warning (as would be the case in a non-sprinklered building) - but here's the difference: the sprinklers should either extinguisher or limit fire growth in the corridor.  The smaller the fire - the less smoke will be produced and so the longer it will take for the smoke layer to descend to head height and threaten egress.  Therefore, the need for doors for smoke control purposes may not be as vital....I take the point re. keeping the storey exits separated and thus "containing the fire" to a smaller compartment but some would argue that sprinklers do the same job. 

Sure, cross corridor doors might increase the level of safety a bit...but then where do you stop: there is always more that can be done.  In other words, are the benefits justified by the time, cost, expense etc i.e. is it reasonable to ask someone to fit corridor doors when they have a sprinkler system.

I've not totally made up my mind on this and, to some extent, I'm playing Devil's Advocate - hence why I'm interested in views. 
 

[Paul2886]

I think there's been some good points made regarding this subject. Sprinklers in a sleeping risk just might not be a single method of ensuring peoples safety because, as stated, they will not activate in the early stages of a fire. I personnally think they have a place but that is in the the protection of property not necessarily life. We all know its the smoke and other beasties that do the harm to persons in a fire. Whilst this stuff is spreading the sprinklers will just sit there observing things until conditions rupture the bulbs and the HD will join them

[kurnal]

Since it is reputed by BASA and others that nobody has ever died as a result of fire in the UK in a building fitted with sprinklers that were maintained and operational that would indicate that thy make a very significant contribution to life safety.
OK they are just taking off in sleeping risks- but the outcome of the Rosepark fire in Scotland seems to indicate that they would have prevented loss of life. Otherwise why would the Scottish Parliament have acted to make them mandatory in Scots care homes?

We cant keep expecting building owners and designers to install sprinklers and then not offer any variation to existing  traditional prescriptive standards. IMO we need to have the courage of our convictions and measure the benefits offered by sprinklers and re-evaluate our requirements elsewhere in the light of these benefits. 

[TickityBoo]

In answer to Paul Martin's point re. HDs and sprinklers doing nothing while smoke spreads: that's why the means of escape has smoke detectors - to give early warning to occupants of a smoke layer just below ceiling level.  If the fire started in a bedroom and the corridor is filling up with smoke, there's a very good chance the HD or sprinkler will have activated in the bedroom limiting fire growth/extinguishing the fire in the bedroom.  Even if they haven't activated (eg. due to a smouldering fire), the optical SDs in the corridor should eventually actuate before egress is comprimised i.e. before the smoke layer descends to head height - (but if its a smouldering fire in the bedroom, is smoke likely to comprimise egress in the corridor before the corridor SD's actuate? - doubtful). Moreover, dare I mention the fact that many hotel bedrooms now have SD's which would have given even earlier warning (although not the hotel I have in mind)?!

If the fire kicks off in the protected corridor - despite the fact that they should be clear of combustibles etc - then the optical smoke detectors will alert occupants. The sprinklers - which can be quick response for life safety purposes - will do their bit in either extinguishing or containing fire growth for all occupants (not just those protected by cross corridor doors).  Without sprinklers, there's a good argument for having cross corridor doors but with them, are these doors justified???...the debate continues!

[CivvyFSO]

I would say that providing that the sprinklers are not there to make up for some other shortcoming, i.e. Extended corridors, single stairs etc, and they were of a life safety standard, then it would definitely be reasonable to omit the cross corridor doors.

It would be a good scenario for probabilistic analysis.

[Izan FSO]

We cant keep expecting building owners and designers to install sprinklers and then not offer any variation to existing  traditional prescriptive standards. IMO we need to have the courage of our convictions and measure the benefits offered by sprinklers and re-evaluate our requirements elsewhere in the light of these benefits. 

Bring on BS 9999 and all the design freedoms it offers....its the way forward...the future!!

[davio1960]

cross doors are required cos tenability levels meybe extremely low

Is that how ten-ab-ility is spelt?

[CivvyFSO]

Davio, the question is, what will make the corridor untenable first... A fire being controlled (hopefully) by a sprinkler system in a room opening up onto a 30m corridor, or an uncontrolled fire opening up onto the same corridor with a cross-corridor door halfway down it? With working fire doors neither should cause much of an issue, so lets assume we have a fire door related problem....

The first scenario, we are still going to have products of combustion, and it could affect the whole corridor meaning everyone would potentially have to be subjected to some of these products of combustion. However, there should be less heat, less CO and CO2, better visibility due to a far less severe fire. Also some people may claim that since the products are in a larger volume of space there will be more dilution, aiding tenability a little more.

But... For 50% of the people on the corridor the second scenario works particularly well. In fact for the people who can make a short dash through the cross-corridor door the second scenario is also quite good. In fact there are a few people who can make a quick dash in the opposite direction into the staircase enclosure or final exit on the affected side too... Hmmm... The longest anyone has to travel is 7.5m into safety...

Decisions decisions... 


And yes, that it how "tenability" is spelt.

However... That is NOT how "maybe" is spelt.

[davio1960]

 6 goals from 32 shots is that similer to mine spellin