Fire Safety in blocks of flats Â– Means of Escape Â– Surface finishes and Benchmark GuidanceÂ– Part 9
Surface finishes within escape routes of a block of flats can affect the spread of fire and are therefore defined within Approved Document B. Surfaces which are combustible are not permitted and only those materials which fall under “Class 0” (equivalent to European class B-s3, d2) are considered appropriate.
Non-combustible materials are finishes such as masonry, brick, concrete, plaster or plaster-board and although walls and ceilings in common areas and corridors may be constructed using some or all of these processes, it may be that there are additional elements which might be difficult to ascertain in an existing block of flats.
An example of this would be a block in which those areas have received multiple coats of paint over the years. This layering of paint can act as a combustible source for a fire and in those cases, the paint should be removed or treated. There are products available which can be used to provide a protective outer coating to painted walls to reduce the chances of fire spread.
If false ceilings have been installed in an existing block and these are made from non-combustible materials, as above, it may be that it is not necessary for cavity barriers to be installed, to sub-divide the area above the ceiling. However, each case should be considered upon its own merits.
Current Benchmark Design Guidance
Where there is a single escape route from a flat door to the stairway, current benchmark guidance is that flats should be separated from the main stairway by a protected lobby or corridor and that the distance of travel from the flat to the protected lobby or stairway should be no more than 7.5m. Ventilation should be in place in both the stairway and protected lobby or corridor, either natural or automatic, and the smoke vents on the floor of fire origin and the vent at the head of the stairway should be opened automatically, where smoke detectors in the common corridor or lobby detect smoke.
In smaller blocks (where the top floor is no more than 11m above ground, there are no more than four storeys in total, the stairway does not connect to a covered car park, the stairway does not serve ancillary rooms – except where they are in protected lobbies, and where adequate venting is in place), there are some relaxations in the provision if given criteria is met.
In those cases, the separation of flats from the single stairway by a protected lobby or corridor remains essential, travel distance is reduced to 4.5m except in those cases where smoke control is installed within the lobby, in which case it reverts to 7.5m as above. However, in blocks where there are only two flats per storey, the dividing lobby is not obligatory if each flat has a protected entrance hall. Where this is the case, the vent which is at the head of the stairway should be automatically opening via smoke detectors.
Next week’s blog will look at blocks of flats with more than one stairway. In the meantime, if you have any queries about a project or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.
The Complete Fire Safety Management Platform is the only fully comprehensive online fire risk assessment and fire risk management platform. Our aim, at CFSM, is to make the process of becoming fire safe, straightforward and, to use our expertise in fire risk assessment and fire safety management to guide you through each step, resulting in your premises meeting all legal, insurance and ethical fire safety considerations.