The LWF Blog

Fire Safety for Facilities Management Personnel – Structural Fire Protection – Part 148

May 9, 2022 12:29 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 147, LWF began to look at building construction and structural fire protection. In part 148, we look at how the requirements within the building regulations, that a building should be constructed to maintain stability for a reasonable period in the event of a fire, translates into structural engineering practicalities.

The actual effects of a fire on the structural stability of a building is a very complex subject matter and would involve an understanding of structural engineering principles. The basic fire safety objective is clear, however, the probability of structural collapse due to fire should be minimised.

Structural elements require a certain level of fire resistance. Approved Document B states the following are structural elements:

• A member forming part of the structural frame of a building or any other beam or column
• A loadbearing wall or part thereof
• Floors
• Galleries (with some exceptions, see below)
• External walls
• Compartment walls (including walls common to two or more buildings)

There are some exclusions, as follows:

• A structure which supports only a roof unless the roof is also used as a floor (e.g. as a car park or means of escape) or, the structure is needed for stability of an external wall needing fire resistance.
• The lowest floor of the building
• A platform floor
• Loading gallery, fly gallery, stage rid, lighting bridge or any gallery provided for similar purposes, or for maintenance/repair.

Approved Document B also sets out periods of fire resistance for elements of structure, according to various categorisations, such as:

• Building usage – different requirements are in place for each of the 11 purpose groups.
• Building height, or building depth where basement levels are involved.
• Sprinkler protection – only relevant in some circumstances.

As a building’s insurers may not feel the standards set out in the Building Regulations are sufficient for property protection purposes (being intended for life safety purposes), and they may have a requirement for longer periods of fire resistance. It is important, therefore, that the fire insurers are consulted at the design stage of a building so that adequate protection can be provided and any additional premiums avoided.

In part 149 of this series, LWF will look at how a building’s construction can help protect against the spread of fire and smoke. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.

Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.