Fire Safety in blocks of flats - Flats in Mixed Use Buildings – Part 21

Whilst many purpose built residential blocks contain just flats, a number of blocks are deemed to be 'mixed use'. The most common configuration is residential units housed above retail space, but also restaurants, shops and offices are commonplace. Typically the commercial space has different entrances and exits, however, they remain part of the building and must therefore be considered from a fire safety point of view.

It is essential, therefore, that the fire-resistant construction of walls and floors is of a high standard allowing a minimum fire resistance of 60 minutes between compartments. These fire precautions will help to sustain the ‘Stay Put’ evacuation policy usually in place in blocks of flats, where only the occupants of the flat – or in this case – alternative use compartment, are evacuated from the building, pending the Fire Service intervention.

It is usually necessary that the common (protected) escape routes provided for the flat occupants, are totally separated from the alternative use parts of the building. These routes should be built with fire-resistant construction.

There are some risk based instances where shared escape routes have been acceptable, for example in buildings of up to and including four storeys, stairways may serve both residential occupancy and alternative use occupancy, however a protected lobby must be in place to separate the stairway from the residential occupancies at each level, thereby reducing the likelihood of smoke ingress into the escape way.

In the case of buildings over four storeys in height, where flats are the main occupancy, the flats should have an escape stairway which is independent of alternative use. However, there may be circumstances where a shared stairway is acceptable, for example in those cases where flats do not comprise the majority of building usage.

In those cases where a block of flats shares a common stairway with alternative use premises, such as shops, other arrangements should be put into place to ensure that occupants of the flats have additional protection in case of fire. One such remedy is that the fire alarm systems present in the non-residential part of the building is extended into the flats. This would, of course, mean that the ‘Stay Put’ evacuation policy is not likely to be appropriate. The likely disruption from having to evacuate a whole block of flats in case of fire means that altering or re-designing the system to avoid this is likely and desirable.

In the case of businesses or shops operating from the non-residential parts of the block, it is possible that each is individually owned and so the responsibility for completing a fire risk assessment would fall to the business owner. However, in the case of smaller shops, where less than 5 employees are involved, it is likely the business owner will not complete a written, formal fire risk assessment. It is possible that owners of small businesses may not be aware of their responsibilities, they may have no formal training in health and safety. It is therefore essential both that the construction and fire safe design of the block as a whole is considered at the time of building and that the owner or manager of the block takes into account the activities of any small businesses operating on the premises and what impact that is likely to have upon the residential areas.

Next week’s blog will look at flats within sheltered housing. 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.