windows on escape stairwells

[ps]

I've been given 2 FRAs of the same property and one one, somebody says "seal the windows in the fire escape stairwell as they introduce oxygen into the escape route and may aid a fire.

The other does not mention it, even though the windows were wide open on the day of the visit?

Anyone give me a steer on who was right?  Stair well in question covers 4 floors and is surrounded by 30 mins fire doors at each level.

[FSO]

Best we start sealing up AOVs then!

[Midland Retty]

It depends on the use of the building, but from a life safety point of view people should have evacuated the building well before the fire is significant size to be aided or effected by things like window openings / ventilation factors and such like.

In general I wouldn't take too much notice about the assessors comments about sealing up windows (IF we are talking about a conventional building - such as an office block, hotel, other sleeping accomodation) etc etc.

Escape routes should be sterile to ensure there is little chance of a fire occurring with in them in the first place. Thus the issue of windows allowing additional air into the area should be of little concern.

People should have evacuated long before considerations relating to the effect of ventilation and other openings have on the behaviour and spread of fire within the building.

There are some exceptions to this and it does depend on what use the building is put to, whether you are looking at building protection, and fire growth factors and if there are any special risks within the building which could aid to rapid or sustained fire spread.

[kurnal]

Is it an office, flats, hotel or a care home?

Windows can be essential to keep an escape route clear of smoke, the issue of oxygen is only a problem if there were combustible materials in the escape route or a lack of fire doors protecting the staircase against fire in the rooms- both of which would be much more significant hazards.

So no the first assessment report is most likely wide of the mark. sounds like an elf and safety person rather than a fire person.

[ps]

Cheers guys, as always, blinding logic and sound sense. 

[nearlythere]

This seems to be someone having difficulty interpreting the principles of fire prevention and their application to buildings.  
The idiots guide to the completion of Fire Risk Assessments recommends the RP identify sources of heat, fuel and oxygen and take measures to control them and this has been taken literally.
The first risk assessor obviously reckons the solution for controlling the source of oxygen to the stairway is to make it air tight.
Struth.

[Mushy]

I've never seen the need for any FR on external windows other than where an external escape is involved. Are they FR glazing?...no...so therefore leave them be

[Phoenix]

Struth.

Absolutely.  What a load of twaddle. 

What do they mean, any way, "Seal the windows..?"  Would that be hermetically?  Or would simple silicone sealant be sufficient?  Comments like that must raise questions about the competence of the assessor.

Stu

[Hightower]

As Mushy implies there is a need for FR on windows opening onto external escape routes as defined in BS9999:2008 18.7. and these windows should be fixed shut.  Obviously not to reduce oxygen but rather to protect the emergency route from products of combustion.

I take it that the windows mentioned were external windows to the emergency route and not between the building and the protected route thus compromising the protected routes necessary 30 minutes fire protection?

It sounds like the first RA may have gotten himself muddled with the different requirements or is it that the protected stairway was added to the building at a later date than the original build and therefore windows from the building open into it?  If so I would treat it as an external escape and indeed seal the windows.

[CivvyFSO]

Mushy and Hightower, I think you have got the wrong end of the stick here. We are not talking about fire resistance to escape routes, I think we are talking about someone who has seen a picture of the fire triangle and thinks that qualifies them to do fire risk assessments.

*** CivvyFSO gets a bag of nails and seals the doors to the BRE shafts up.

Pesky oxygen!

 

[nearlythere]

Mushy and Hightower, I think you have got the wrong end of the stick here. We are not talking about fire resistance to escape routes, I think we are talking about someone who has seen a picture of the fire triangle and thinks that qualifies them to do fire risk assessments.

*** CivvyFSO gets a bag of nails and seals the doors to the BRE shafts up.

Pesky oxygen!

 

I think you mean the square of fire Civvy. Heat, Fuel, Oxygen and Senior Officer. Remove any one and ................

[Mushy]

Mushy and Hightower, I think you have got the wrong end of the stick here. We are not talking about fire resistance to escape routes, I think we are talking about someone who has seen a picture of the fire triangle and thinks that qualifies them to do fire risk assessments.

*** CivvyFSO gets a bag of nails and seals the doors to the BRE shafts up.

Pesky oxygen!

 

no I knew what i was saying 

I mentioned both scenarios in my post...and said that FR to external winders aint necessary...unless it's for external escapes

[GB]

The original question posed states that the windows lead onto a fire escape stairwell. It also states that the doors leading onto the 4 storey stairwell are provided with 30 minutes fire resistance. I would concur with Mushy that if the stairwell is used as an escape stair, that people would have to pass the windows as part of their escape, they should be fixed shut and in addition at least 30 minutes fire resisting. Otherwise what on earth is the point of having a well fitted FD30(s) in the 1st place? Could it be the case that the 1st FRA has confused the term 'sealed' and 'fixed shut'?

Saying that....I may have the scenario completely wrong and I haven't had my first coffee this morning

[kurnal]

Good point GB - you read the posting in a different way to the rest of us. But PS did say that the hazard was that the windows would introduce oxygen to the  escape route and may aid the fire.

Your perspective is different - do the windows negate the fire resistance of the protected route? Are the windows likely to allow the fire to spread from the accommodation into the escape route?

Thats not the way I read the original posting but if this is what the fire risk assessor was getting at then it is a very valid point.

[Tom Sutton]

The original question posed states that the windows lead onto a fire escape stairwell.

No not quite it said "seal the windows in the fire escape stairwell" as these will be on an external wall, where is the fire treat coming from, the adjacent building? If they are not on an external wall then they would be borrowed lights different scenario. I am with NT on this one.