BS 5839-1 Category L3 Systems

[Suttonfire]

Hi,

Could anyone confirm whether loft areas above an escape route (with an access hatch in the escape route), and larger cupboards (which open on to an escape route) should be fitted with detection in accordance with BS 5839-1. I can only find reference to cupboards in relation to L1 systems (small cupboards defined as less than 1m2). Would a larger cupboard be comparable to a 'room opening on to an escape route'.

I can also see no direct reference to roof voids accessed via an escape route in relation to an L3 system.

Thanks

[John Webb]

Is a fire in the loft space likely to develop to the stage where it could break through the ceiling of the escape route before building users are aware of the fire? If so, then I would consider fitting the loft with detectors so that the escape route is protected.

[Davo]

Suttonfire

Access to what?
Contractors, need I say more, if I remember correctly some 30% of business premise fires are caused by contractors hot work


davo

[kurnal]

I think this is covered either as a room adjoining an escape route or a void exceeding 800mm?
If I recall Toddy goes into it in his book on BS5839-1.

[Bill J]

Hi

There are a number of factors, but the simplest point is that if the void is greater than 1.5m it could be considered as a room, otherwise it should be specifically risk assessed and confirmed to be free of ignition sources and combustible materials, it should be provided with detection.

If the void is free of ignition sources, has no fire load, and is compartmented adequately, if there is no reason for persons to gain access, could the hatch be removed and the void sealed?

If it is likely that service or other works are required within the void this may increase a risk then either adequately manage, or provide detection.

Same goes for cupboards.

Also, as it is mentioned in "L1" it also applies to other "L" categories in the areas they apply.

Bill

[David Rooney]

I would only further add:

22.2 d) If the system Category is such that automatic fire detection should be provided in any area that contains a horizontal void of 800 mm or more in height, automatic fire detection should also be provided in the void. Voids less than 800 mm in height need not be protected, unless either:

1) the void is such that extensive spread of fire or smoke, particularly between rooms and compartments, can take place before detection; or

2) on the basis of a fire risk assessment, the fire risk in the void is such as to
warrant protection of the void.


So regardless of category, if the escape route requires AFD to meet the category then any accessible void above it should have AFD subject to the conditions above.