Items where Subject is "Section 00: Approved Document B: Fire safety – dwellings"
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This approved document has been published in two volumes. Volume 1 deals solely with dwellings, including blocks of flats, while Volume 2 deals with all other types of building covered by the Building Regulations
Volume 1 purpose groups
Purpose for which the building or compartment of a building is intended to be used
Residential(dwellings)
1(a)(1)Flat.
1(b)(2)Dwellinghouse that contains a habitable storey with a floor level a minimum of 4.5m above ground level up to a maximum of 18m.
(3)1(c)(2)(4)Dwellinghouse that does not contain a habitable storey with a floor level a minimum of 4.5m above ground level.
Where Part B applies to existing buildings, particularly buildings of special architectural or historic interest for which the guidance in this document might prove too restrictive, some variation of the provisions in this document may be appropriate. In such cases, it is appropriate to assess the hazard and risk in the particular case and consider a range of fire safety features in that context.
While many of the provisions in this approved document for means of escape from flats are applicable to sheltered housing, the nature of the occupancy may necessitate some additional fire protection measures. The extent of such measures will depend on the form of the development. For example, a group of specially adapted bungalows or two storey flats, with few communal facilities, will not need to be treated differently from other single storey or two storey dwellinghouses or flats.
Fire safety engineering might provide an alternative approach to fire safety. Fire safety engineering may be the only practical way to achieve a satisfactory standard of fire safety in some complex buildings and in buildings that contain different uses.
Fire safety engineering may also be suitable for solving a specific problem with a design that otherwise follows the provisions in this document.
BS 7974 and supporting published documents (PDs) provide a framework for and guidance on the application of fire safety engineering principles to the design of buildings.
Where a building or compartment has more than one use, it is appropriate to assign each different use to its own purpose group in the following situations.
a. If the ancillary use is a flat.
b. If both of the following apply.
i. The building or compartment has an area of more than 280m2.
ii. The ancillary use relates to an area that is more than one-fifth of the total floor area of the building or compartment.
c. In ‘shop and commercial’ (purpose group 4) buildings or compartments, if the ancillary use is storage and both of the following apply.
i. The building or compartment has an area of more than 280m2.
ii. The storage area comprises more than one-third of the total floor area of the building or compartment.
Where there are multiple main uses that are not ancillary to one another (for example, shops with independent offices above), each use should be assigned to a purpose group in its own right.
Where there is doubt as to which purpose group is appropriate, the more onerous guidance should be applied.
In sheltered housing, the guidance in Approved Document B Volume 2 should be consulted for the design of communal facilities, such as a common lounge.
This approved document includes reference to selected guidance for buildings other than dwellings. For the design of mixed use buildings, Approved Document B Volume 2 should be consulted in addition to the guidance contained in this approved document.
Where a complex mix of uses exists, the effect that one use may have on another in terms of risk should be considered. It could be necessary to use guidance from both volumes, apply other guidance (such as from HTM 05-02 or Building Bulletin 100), and/or apply special measures to reduce the risk.
Requirements B1–B5 of Schedule 1 to the Building Regulations are dealt with separately in one or more sections. Each requirement is shown at the start of the relevant sections.
The provisions in this document have the following aims.
Requirement B1: When there is a fire, ensure both:
a. satisfactory means of sounding an alarm
b. satisfactory means of escape for people.
Requirement B2: Inhibit the spread of fire over internal linings of buildings.
Requirement B3: The building must be built such that all of the following are achieved in the event of a fire:
a. the premature collapse of the building is avoided
b. sufficient fire separation is provided within buildings and between adjoining buildings
c. automatic fire suppression is provided where necessary
d. the unseen spread of fire and smoke in cavities is restricted.
Requirement B4: Restrict both:
a. the potential for fire to spread over external walls and roofs (including compliance with regulations 6(4) and 7(2))
b. the spread of fire from one building to another.
Requirement B5: Ensure both:
a. satisfactory access for the fire service and its appliances
b. facilities in buildings to help firefighters save the lives of people in and around buildings.
Regulation 38: Provide fire safety information to building owners.
Guidance is given on each aspect separately, though many are closely interlinked. The document should be considered as a whole. The relationship between different requirements and their interdependency should be recognised. Particular attention should be given to the situation where one part of the guidance is not fully followed, as this could have a negative effect on other provisions.
Guidance on matters that refer to more than one section of this document can be found in the following appendices.
Appendix A: Key terms
Appendix B: Performance of materials, products and structures
Appendix C: Fire doorsets
Appendix D: Methods of measurement
Appendix E: Sprinklers
Appendix F: Standards referred to
Appendix G: Documents referred to
The Building Regulations do not impose any requirements on the management of a building, but do assume that it will be properly managed. This includes, for example, keeping protected escape routes virtually ‘fire sterile’.
Appropriate fire safety design considers the way in which a building will be managed. Any reliance on an unrealistic or unsustainable management regime cannot be considered to have met the requirements of the regulations.
Once the building is in use, the management regime should be maintained and a suitable risk assessment undertaken for any variation in that regime. Failure to take proper management responsibility may result in the prosecution of an employer, building owner or occupier under legislation such as the Regulatory Reform (Fire Safety) Order 2005.
The Building Regulations are intended to ensure a reasonable standard of life safety in a fire. The protection of property, including the building itself, often requires additional measures. Insurers usually set higher standards before accepting the insurance risk. Many insurers use the RISC Authority Design Guide for the Fire Protection of Buildings by the Fire Protection Association (FPA) as a basis for providing guidance to the building designer on what they require. Further information on the protection of property can be obtained from the FPA website: www.thefpa.co.uk.
The fire safety aspects of the Building Regulations aim to achieve reasonable standards of health and safety for people in and around buildings. People, regardless of ability, age or gender, should be able to access buildings and use their facilities. The fire safety measures incorporated into a building should take account of the needs of everyone who may access the building, both as visitors and as people who live or work in it. It is not appropriate, except in exceptional circumstances, to assume that certain groups of people will be excluded from a building because of its use. The provisions in this approved document are considered to be of a reasonable standard for most buildings. However, some people’s specific needs might not be addressed. In some situations, additional measures may be needed to accommodate these needs. This should be done on a case- by-case basis.
The fire safety requirements of the Building Regulations will probably be satisfied by following the relevant guidance in this approved document. However, approved documents provide guidance for some common building situations, and there may be alternative methods of complying with the Building Regulation requirements. If alternative methods are adopted, the overall level of safety should not be lower than the approved document provides. It is the responsibility of those undertaking the work to demonstrate compliance. If other standards or guidance documents are adopted, the relevant fire safety recommendations in those publications should be followed in their entirety. However, in some circumstances it may be necessary to use one publication to supplement another. Care must be taken when using supplementary guidance to ensure that an integrated approach is used in any one building. Guidance documents intended specifically for assessing fire safety in existing buildings often include less onerous provisions than those for new buildings and are therefore unlikely to be appropriate for building work that is controlled by the Building Regulations. Buildings for industrial and commercial activities that present a special fire hazard, e.g. those that sell fuels, may require additional fire precautions to those in this approved document.