News special: Smoke signals

Important new fire safety rules governing building design and construction are about to come into force. Approved Document, Part B will be adopted in England and Wales on 6 April this year. It draws on the lessons learnt following 9/11, and on the years since the 2000 edition of Part B Building Regulations was introduced. Any Building Regulations applications made after that date must comply with the changes.

One of the most significant changes is the introduction of a new Building Regulation, 16B, which requires that “where building work involves the erection or extension of a relevant building, or a relevant change of use of a building, fire safety information shall be given to the responsible person at the completion of the project or when the building or extension is first occupied”. The word “relevant” here refers to all buildings covered by the Regulatory Reform (Fire safety) Order 2005 – ie all buildings except single-family dwelling houses, but including the common parts of blocks of flats. The scope of information required to satisfy this regulation will vary with the complexity of the building, but should cover the design and construction of the building or extension, and the services, fittings and equipment provided in connection with the building.

As a minimum, the information should include:

• any assumptions made in the development of the fire safety strategy and the design of any fire safety systems
• any assessment or analysis of fire risk
• all assumptions made regarding the management of the building
• details of the evacuation strategy and escape routes
• details of passive fire compartmentation, including the location of fire walls, floors, cavity barriers fire doors etc.
• the location of active fire systems, including fire detector locations, call points, alarm sounders and emergency communication systems, CCTV, automatic suppression systems, firefighting equipment and facilities provided for use by the fire service, both internally and externally
• details of facilities for the evacuation of disabled people.

Significantly, apartment buildings over 30 m in height should now be provided with domestic sprinklers, and there are also some changes

to the way in which common areas are to be kept free from smoke during a fire, including the use of mechanical ventilation to these areas in lieu of smoke shafts or automatic opening vents. In recognition of the fact that there is no ongoing control over individual flats once occupied, the need to provide self-closing devices to fire doors within flats and apartments has been removed – a move expected to result in a saving of more than £8 million a year.

Also changing is the way in which access for the fire service is provided to tall buildings. Additional rising mains now need to ensure that every part of every storey over 18 m in height is within 45 m of a fire main outlet located in a protected escape stair; and within 60 m from a fire main outlet located within a firefighting shaft. Thought must also be given to the interaction between fire crews entering the building and the escaping occupants – possibly requiring additional protected stair cores. Both of these provisions are included as a result of the experiences of 9/11.

Facades that are shared must now be designed to limit the potential for spread of fire between adjacent buildings and buildings that are on the same site but operated by different organisations. Compartment walls must be designed to accommodate the predicted deflection of the floor above during a fire, either by having a suitable head deflection detail or by being designed to carry the additional load imposed by the sagging floor.

Warehouses

There is a new national limit on the size of single-storey warehouses, which supersedes any limitations imposed by the local Acts, which will, in time, be repealed. The maximum floor area for any single-storey warehouse will be 20,000 m2, with an associated height limit of 18 m to the underside of the roof or ceiling. Any building that exceeds these limits should either be provided with an automatic sprinkler system or with additional fire compartmentation. Related to this, ‘self-storage warehouses’ have been assigned to building Purpose Group 4 (shop and commercial), rather than Purpose Group 7 (storage), thereby limiting the size of any single compartment to 2000 m2 in the absence of sprinklers.

Lesser impact

Other amendments that come into force, but which are likely to have less impact include:

• guidance on the third-party certification and accreditation schemes, and how these should be used by Building Control bodies
• new guidance on the specification and installation of fire dampers
• reference to DfES Building Bulletin 100 for the design of schools
• guidance on the means of escape for disabled people and for buildings with open spatial planning
• guidance on additional private hydrants for buildings located some distance from a highway.

When the government was investigating the need to update the fire rules it conceded that the changes would have a higher cost for both industry and the public sector. However, it concluded that “these would be outweighed by the benefits, particularly in terms of a lower incidence of fires and to reductions in both deaths and injuries as a result of fires”. Only time will tell whether the new regulations will achieve these important goals.