(Factory) Corridor Doors

[TickityBoo]

I'd be interested to hear views on the following:

I accept that doors off an unprotected corridor do not require to be s/c fire doors.  Nevertheless, any door will, to some extent, when closed, restrict the spread of smoke/fire into the means of escape (corridor).

However, in many premises, particularly factories, it is common to find wide doorways off corridors with vertical hanging plastic strips which allow for pallets of stock etc to be easily moved between rooms. 

My question is - what is the point of keeping a corridor clear of hazards if the rooms off the corridors have hazards within them and are effectively "open" to the corridor? I know that high ceilings in the "open" rooms off the corridor will reduce smoke travel into the corridor but is this enough?  Perhaps high ceilings and comprehensive detection combined is enough to reduce the risk to persons on the premises?

On the other hand, many factories may not have corridors and so the means of escape is through open plan areas which have hazards aplenty, so what's the problem? 

NB in all these examples, I am assuming that travel distance is not a problem.  Thoughts please...

[wee brian]

what is the point of keeping a corridor clear of hazards ?

So people don't fall over them whilst escaping.

[nearlythere]

I'd be interested to hear views on the following:

I accept that doors off an unprotected corridor do not require to be s/c fire doors.  Nevertheless, any door will, to some extent, when closed, restrict the spread of smoke/fire into the means of escape (corridor).

However, in many premises, particularly factories, it is common to find wide doorways off corridors with vertical hanging plastic strips which allow for pallets of stock etc to be easily moved between rooms. 

My question is - what is the point of keeping a corridor clear of hazards if the rooms off the corridors have hazards within them and are effectively "open" to the corridor? I know that high ceilings in the "open" rooms off the corridor will reduce smoke travel into the corridor but is this enough?  Perhaps high ceilings and comprehensive detection combined is enough to reduce the risk to persons on the premises?

On the other hand, many factories may not have corridors and so the means of escape is through open plan areas which have hazards aplenty, so what's the problem? 

NB in all these examples, I am assuming that travel distance is not a problem.  Thoughts please...

Are you talking about fire hazards or trip or obstruction hazards?
The point of keeping hazards out of corridors, unless in a dead end condition, is more to do with keeping the escape route clear of obstruction. It is the same in work rooms off corridors where clearways must be maintained around stock and plant so that persons can also escape from the room without hinderance.  Travel distances also apply within rooms and you can have dead end conditions where you have fixed shelving or plant and associated equipment.

[TickityBoo]

Wee Brian and Nearlythere, I should clarify that I'm talking about significant fire hazards i.e. combustibles and potential sources of ignition and not obstructions.  Any fire safety guide (and common sense) will tell you to keep escape routes i.e. corridors (particularly protected but also unprotected) clear of fire hazards viz electrical equipment, portable heaters, refuse and catering supplies, cooking appliances etc, etc.  This is more to do with reducing the likelihood of a fire occurring in the first place - a fire in an escape route places occupants at significant risk. There could also be an issue with escape route width but that was not the point of my question; sorry if that wasn't clear.

[nearlythere]

Wee Brian and Nearlythere, I should clarify that I'm talking about significant fire hazards i.e. combustibles and potential sources of ignition and not obstructions.  Read any fire safety guide and it will tell you to keep escape routes i.e. corridors (particularly protected but also unprotected) clear of fire hazards viz electrical equipment, portable heaters, refuse and catering supplies, cooking appliances etc, etc. 

TB. If you consider them to be significent fire hazards then control measures are needed to reduce them to a tolerable hazard.
Items that are a source of fuel, pose an ignition risk, or are combustible and likely to increase the fire loading or spread of fire, should not be located on any corridor or stairway that will be used as an escape route. Such items include:
• portable heaters, e.g. bottled gas (LPG) or electric radiant heaters and electric convectors or boilers;
• gas cylinders for supplying heaters;
• cooking appliances; and
• unenclosed gas pipes, meters, and other fittings.

However, depending on the findings of your risk assessment and where more than one escape route is available, items such as those below may be acceptable if the minimum exit widths are maintained and the item presents a
relatively low fire risk:
• non-combustible lockers;
• vending machines;
• small items of electrical equipment (e.g. photocopiers); and
• small coat racks and/or small quanities of upholstered furniture which meets BS 7176 or the Furniture and Furnishings (Fire Safety) Regulations 1988.

[PhilB]

I accept that doors off an unprotected corridor do not require to be s/c fire doors.  Nevertheless, any door will, to some extent, when closed, restrict the spread of smoke/fire into the means of escape (corridor).

Hi TickityBoo

There are two reasons that we would want corridors clear. The obvious one, as has been pointed out is so that the means of escape is not obstructed.

The other is that our building design guides and codes work on the premise that we may have fires in rooms but we should not have fires in corridors. If we had a fire load in a corridor it would be more like a room with an increased likelihood of fire and an increased severity of fire. Also it would in effect make every room off the corridor an inner room.

ADB correctly points out, as do you that even in unprotected corridors the doors and partitions do restrict fire and smoke spread.

Some of the older guides required corridor or lobby approach to stairs if they required additional protection. Note that corridors, not protected corridors were required. The premise being that a fire that occurs in a room would generate smoke pressure but that the pressure would reduce as the smoke entered the corridor and so would not compromise the stair. The unprotected corridor performed the same function as the lobby, i.e smoke control.

So you are quite correct to be concerned in the situation you describe, but only if the corridor is there to afford addtional protection to a stairway. You need to understand how the building was designed and what purpose the corridor is intended to fulfil.

If this is a single storey factory with escape in two directions I would not care if the corridor doors were removed, wedged open, or replaced with blinds.

If this corridor links to stairways serving upper floors the corridor may require doors to be in place for smoke control purposes.

[TickityBoo]

Thanks Nearlythere, and I agree with what you've said.  Going back to the original point though about these vertical hanging thick plastic strips across wide doorways - you can see my point.  In a factory you can have processing areas with significant fire hazards which are effectively open to the corridor means of escape as these strips will not hold back fire or smoke.  There doesn't seem much point therefore in asking for the corridor means of escape to be as free of fire hazards as possible if an open room off the corridor has them aplenty.

I'm just curious to hear if people think this is ok where you've got high ceilings and adequate detection or whether the doorways should really have doors.  Perhaps I'm answering my own question here as I am aware of open plan factories where there are no corridor means of escape and there are loads of fire hazards(not presenting an obstruction) around.  You can't keep a corridor means of escape free of fire hazards if you don't have a corridor in the first place!  

[nearlythere]

TB. Have a look at this.
http://www.communities.gov.uk/documents/fire/pdf/150952.pdf

[PhilB]

TB. Have a look at this.
http://www.communities.gov.uk/documents/fire/pdf/150952.pdf

Problem is Nearlythere those books with lots of pictures don't really explain any reasoning behind the principles. Never mind I shall go and lie down again.

[nearlythere]

TB. Have a look at this.
http://www.communities.gov.uk/documents/fire/pdf/150952.pdf

Problem is Nearlythere those books with lots of pictures don't really explain any reasoning behind the principles. Never mind I shall go and lie down again.

No, but it does help to give one an understanding of the principles of risks and hazards and their control and the protection of corridors and stairways and, there is lots of other relevant written bits around the many pictures.

[TickityBoo]

Hi Phil

So you are quite correct to be concerned in the situation you describe, but only if the corridor is there to afford addtional protection to a stairway. You need to understand how the building was designed and what purpose the corridor is intended to fulfil.

If this is a single storey factory with escape in two directions I would not care if the corridor doors were removed, wedged open, or replaced with blinds.

The corridors I've got in mind do not serve a stair.  It is a single storey factory.  Interesting that you say you're not bothered about removing corridor doors to rooms where the corridor does not serve a stair or is a dead end.  I follow your logic re. other available escape routes but will this not potentially lead to extended travel times - alarm sounds, evacuation starts, occupants enter corridor then round a corner to discover smoke ahead, they then have to retrace their steps potentially against the flow of evacuation...?

I've always thought of corridors as having doors to prevent fire spread/smoke spread and to remove doors would seem to open the corridor up to include possibly high hazard areas.  My take was that corridors are low risk due to very few, if any, fire hazards and very low risk where they are protected zones as these should be totally sterile areas.

Nearlythere - I've looked at the CLG guide before but it doesn't really go into the area of removing doors from unprotected corridors.

[PhilB]

Hi Phil


The corridors I've got in mind do not serve a stair.  It is a single storey factory.  Interesting that you say you're not bothered about removing corridor doors to rooms where the corridor does not serve a stair or is a dead end.  I follow your logic re. other available escape routes but will this not potentially lead to extended travel times - alarm sounds, evacuation starts, occupants enter corridor then round a corner to discover smoke ahead, they then have to retrace their steps potentially against the flow of evacuation...?

I've always thought of corridors as having doors to prevent fire spread/smoke spread and to remove doors would seem to open the corridor up to include possibly high hazard areas.  My take was that corridors are low risk due to very few, if any, fire hazards and very low risk where they are protected zones as these should be totally sterile areas.

No I don't think it will cause a problem with extended travel times (distances) because we have never measured travel time or distance to a corridor, protected or unprotected.

The removal of the doors does not effect how far you need to travel to a place of comparative safety. If occupants encounter smoke, they can turn their backs and walk to safety in another direction. Against the flow??? not a problem in a factory I would suggest...but you do need to take occupants likely behaviour into account together with many other factors.

I think you asked a very sensible question i.e. are doors required on unprotected corridors...the answer is yes they are sometimes but to undertsand when they are you need an understanding of the basic principles of fire safety, unfortunately you will struggle to find the answer in the CLG guides.

[colin todd]

Tickers, Its all about pragmatism. The difference between an open plan office and an office corridor is the volume available to fill with smoke before the smoke layer descends to a level that will pose a threat to escaping occupants. In an office, the ceiling height might be low, a fire in a cellular office may go undiscovered before detection and each of the occupants of other cellular offices may be unaware until its too late. Thats why doors cannot be removed even if the corridor is not a protected zone.
In a factory, the corridors you are talking about are often high spaces and quite wide for transport of materials. The spaces off are often under human surveillance, although the need for AFD might be considered. Usually a different scenario and in practice doors would impede flow and get a hammering.