Section 0 General introduction Fire safety

Fire safety

  1. Scope
    1. Arrangement of sections
      1. Appendices: provisions common to more than one of Part B’s requirements
        1. Fire performance of materials, products and structures
          1. Fire doors
            1. Methods of measurement
              1. Purpose groups
                1. Definitions
                2. Building maintenance and the provision of information
                  1. Property protection
                    1. Independent schemes of certification and accreditation
                      1. Residential sprinklers
                        1. Inclusive design
                          1. Material alteration
                            1. Alternative approaches
                              1. Registered group homes
                                1. Adult placements
                                  1. Sheltered housing
                                    1. Fire safety engineering
                                      1. Buildings of special architectural or historic interest

                                      Scope

                                      0.1 Approved Document B (Fire safety) has been published in two volumes. Volume 1 deals solely with dwellinghouses (see Appendix E and Building Regulation 2(1)), while Volume 2 deals with all other types of building covered by the Building Regulations. Where very large (over 18m in height) or unusual dwellinghouses are proposed some of the guidance in Volume 2 may be needed to supplement that given by Volume 1.

                                      Arrangement of sections

                                      0.2 The functional requirements B1 to B5 of Schedule 1 of the Building Regulations are dealt with separately in one or more Sections. The requirement is reproduced at the start of the relevant Sections, followed by an introduction to the subject. 0.3 The provisions set out in this document deal with different aspects of fire safety, with the following aims:

                                      • B1: To ensure satisfactory provision of means of giving an alarm of fire and a satisfactory standard of means of escape for persons in the event of fire in a building.
                                      • B2: To ensure fire spread over the internal linings of buildings is inhibited.
                                      • B3: To ensure the stability of buildings in the event of fire; to ensure that there is a sufficient degree of fire separation within buildings and between adjoining buildings; to provide automatic fire suppression where necessary; and to inhibit the unseen spread of fire and smoke in concealed spaces in buildings.
                                      • B4: To ensure external walls and roofs have adequate resistance to the spread of fire over the external envelope, and that spread of fire from one building to another is restricted.
                                      • B5: To ensure satisfactory access for fire appliances to buildings and the provision of facilities in buildings to assist firefighters in the saving of life of people in and around buildings.
                                        0.4 Whilst guidance appropriate to each of these aspects is set out separately in this document, many of the provisions are closely interlinked. For example, there is a close link between the provisions for means of escape (B1) and those for the control of fire growth (B2), fire containment and/or suppression (B3) and facilities for the fire and rescue service (B5). Similarly there are links between B3 and the provisions for controlling external fire spread (B4), and between B3 and B5. Interaction between these different requirements should be recognised where variations in the standard of provision are being considered. A higher standard under one of the requirements may be of benefit in respect of one or more of the other requirements. The guidance in the document as a whole should be considered as a package aimed at achieving an acceptable standard of fire safety.

                                      Appendices: provisions common to more than one of Part B’s requirements

                                      0.5 Guidance on matters that refer to more than one of the Sections is in a series of Appendices, covering the following subjects:

                                      • Appendix A: fire performance of materials, products and structures
                                      • Appendix B: provisions regarding fire doors
                                      • Appendix C: methods of measurement
                                      • Appendix D: a classification of purpose groups
                                      • Appendix E: definitions
                                      • Appendix F: Standards and other publications referred to.
                                       

                                      Fire performance of materials, products and structures

                                      0.6 Much of the guidance throughout this document is given in terms of performance in relation to standard fire test methods. Details are drawn together in Appendix A to which reference is made where appropriate. In the case of fire protection systems, reference is made to standards for system design and installation. Standards referred to are listed in Appendix F.

                                      Fire doors

                                      0.7 Guidance in respect of fire doors is set out in Appendix B.

                                      Methods of measurement

                                      0.8 Some form of measurement is an integral part of much of the guidance in this document and methods are set out in Appendix C.

                                      Purpose groups

                                      0.9 Much of the guidance in this document is related to the use of the building. The use classifications are termed purpose groups, and they are described in Appendix D. This document deals only with buildings in Purpose Groups 1b and 1c.

                                      Definitions

                                      0.10 The definitions are given in Appendix E.

                                      Building maintenance and the provision of information

                                      0.11 For the provisions of this Approved Document to be effective it is essential that the measures incorporated into the design of a dwellinghouse are adequately maintained. Building Regulations do not impose any requirements on the management of a building. However, the eventual owners and occupiers should be provided with sufficient information to operate, maintain and use the building in reasonable safety. For individual dwellinghouses, basic advice on the proper use and maintenance of systems provided in the building, such as emergency egress windows, fire doors, smoke alarms, sprinklers etc., can help to ensure that these systems are maintained and kept available for use. Householders should also be made aware that unauthorised material alterations (see paragraph 0.20) may leave them liable to prosecution. In providing fire protection of any kind in dwellinghouses, it should be recognised that measures which significantly interfere with the day-to-day convenience of the occupants may be less reliable in the long term.

                                      Property protection

                                      0.12 There are often many stakeholders, including insurers, who have a valid interest in the fire protection measures which are incorporated into a building's design. To ensure that the most effective fire protection measures are applied which are appropriate to the specific property, early consultation with the main stakeholders is essential. Failure to consult with stakeholders at an early stage could result in additional measures being required after completion, the use of the building being restricted, or insurance premiums and/or deductibles being increased. Building Regulations are intended to ensure that a reasonable standard of life safety is provided in case of fire. The protection of property, including the building itself, often requires additional measures and insurers will, in general, seek their own higher standards before accepting the insurance risk. Guidance for asset protection in the Civil and Defence Estates is given in the Crown Fire Standards published by the Property Advisers to the Civil Estate (PACE).

                                      Independent schemes of certification and accreditation

                                      0.13 Much of the guidance throughout this document is given in terms of performance in relation to standard fire test methods. Details are drawn together in Appendix A to which reference is made where appropriate. In the case of fire protection systems, reference is made to standards for system design and installation. Standards referred to are listed in Appendix F. 0.14 Since the performance of a system, product, component or structure is dependent upon satisfactory site installation, testing and maintenance, independent schemes of certification and accreditation of installers and maintenance firms of such will provide confidence in the appropriate standard of workmanship being provided. Confidence that the required level of performance can be achieved will be demonstrated by the use of a system, material, product or structure which is provided under the arrangements of a product conformity certification scheme and an accreditation of installers scheme. Third party accredited product conformity certification schemes not only provide a means of identifying materials and designs of systems, products or structures which have demonstrated that they have the requisite performance in fire, but additionally provide confidence that the systems, materials, products or structures actually supplied are provided to the same specification or design as that tested/assessed. Third party accreditation of installers of systems, materials, products or structures provides a means of ensuring that installations have been conducted by knowledgeable contractors to appropriate standards, thereby increasing the reliability of the anticipated performance in fire. Many certification bodies which approve such schemes are accredited by UKAS. 0.15 Building Control Bodies may accept the certification of products, components, materials or structures under such schemes as evidence of compliance with the relevant standard. Similarly, Building Control Bodies may accept the certification of the installation or maintenance of products, components, materials or structures under such schemes as evidence of compliance with the relevant standard. Nonetheless, a Building Control Body will wish to establish, in advance of the work, that any such scheme is adequate for the purposes of the Building Regulations.

                                      Residential sprinklers

                                      0.16 Sprinkler systems installed in dwellinghouses can reduce the risk to life and significantly reduce the degree of damage caused by fire. Sprinkler protection can also sometimes be used as a compensatory feature where the provisions of this Approved Document are varied in some way. 0.17 Where a sprinkler system is recommended within this document it should be designed and installed in accordance with BS 9251:2005 Sprinkler systems for residential and domestic occupancies - Code of practice and DD 252:2002 Components for residential sprinkler systems - Specification and test methods for residential sprinklers. Where sprinklers are provided, it is normal practice to provide sprinkler protection throughout the building. However, where the sprinklers are being installed as a compensatory feature to address a specific risk or hazard it may be acceptable to protect only part of a building. Further guidance can also be found in Sprinklers for Safety: Use and Benefits of Incorporating Sprinklers in Buildings and Structures, BAFSA (2006) ISBN: 0 95526 280 1. 0.18 There are many alternative or innovative fire suppression systems available. Where these are used it is necessary to ensure that such systems have been designed and tested for use in domestic buildings and are fit for their intended purpose.

                                      Inclusive design

                                      0.19 The fire safety aspects of the Building Regulations are made for securing reasonable standards of health and safety of persons in and about buildings. This is intended to include all people including people with disabilities. The provisions set out in this Approved Document are considered to be a reasonable standard for most buildings. However, there may be some people whose specific needs are not addressed. In some situations additional measures may be needed to accommodate these needs. This should be done on a case by case basis.

                                      Material alteration

                                      0.20 Under Regulation 3, the term "material alteration" is defined by reference to a list of "relevant requirements" of Schedule 1 to the Building Regulations. That list includes the requirements of Parts B1, B3, B4 and B5. This means that an alteration which, at any stage of the work, results in a building being less satisfactory than it was before in relation to compliance with the requirements of Parts B1, B3, B4 or B5 is a material alteration, and is therefore controlled by Regulation 4 as it is classed as "building work". Regulation 4(1) requires that any building work carried out in relation to a material alteration complies with the applicable requirements of Schedule 1 to the Regulations, while Regulation 4(3) requires that once that building work has been completed, the building as a whole must comply with the relevant requirements of Schedule 1 or, where it did not comply before, must be no more unsatisfactory than it was before the work was carried out.

                                      Alternative approaches

                                      0. 21 The fire safety requirements of the Building Regulations should be satisfied by following the relevant guidance given in this Approved Document. However, Approved Documents are intended to provide guidance for some of the more common building situations and there may well be alternative ways of achieving compliance with the requirements. If other codes or guides are adopted, the relevant recommendations concerning fire safety in the particular publication should be followed, rather than a mixture of the publication and provisions in the relevant sections of this Approved Document. However, there may be circumstances where it is necessary to use one publication to supplement another. Guidance documents intended specifically for assessing fire safety in existing buildings will often include provisions which are less onerous than those set out in this Approved Document or other standards applicable to new buildings. As such, these documents are unlikely to be appropriate for use where building work, controlled by the Regulations, is proposed.

                                      Registered group homes

                                      0.22 Depending on the nature of the occupants and their management needs, it may be acceptable to treat an unsupervised group home with up to six residents as an ordinary dwellinghouse. However, because such places have to be registered, the registration authority should be consulted to establish whether there are any additional fire safety measures that the authority will require. Where an existing house of one or two storeys is to be put to use as an unsupervised group home for not more than 6 mental health service users, it should be regarded as a Purpose Group 1(c) building if the means of escape are provided in accordance with HTM 88: Guide to fire precautions in NHS housing in the community for mentally handicapped (or mentally ill) people. Where the building is new, it may be more appropriate to regard it as being in Purpose Group 2(b).

                                      Adult placements

                                      0.23 Where a dwellinghouse is used for the purposes of an Adult Placement Scheme and fulfils the criteria of the Adult Placement Schemes (England) Regulations (SI 2004 No 2070) and where no building work is proposed, the guidance in the joint code of practice published by the National Association of Adult Placement Services (www.naaps.co.uk) should be sufficient to satisfy Part B of the Building Regulations if a material change of use has taken place.

                                      Sheltered housing

                                      0.24 Where a sheltered housing scheme consists of individual houses then each unit may be designed in accordance with this volume of Approved Document B. Any communal facilities that are provided within the scheme should be designed in accordance with Approved Document B Volume 2 (Buildings other than dwellinghouses).

                                      Fire safety engineering

                                      0.25 Fire safety engineering can provide an alternative approach to fire safety. It may be the only practical way to achieve a satisfactory standard of fire safety in some large and complex buildings. Fire safety engineering may also be suitable for solving a problem with an aspect of the building design which otherwise follows the provisions in this document. British Standard BS 7974:2001 Application of fire safety engineering principles to the design of buildings and supporting published documents (PDs) provide a framework and guidance on the design and assessment of fire safety measures in buildings. Following the discipline of BS 7974 should enable designers and Building Control Bodies to be aware of the relevant issues, the need to consider the complete fire safety system, and to follow a disciplined analytical framework. 0.26 Factors that should be taken into account include:

                                      • a. the anticipated probability of a fire occurring;
                                      • b. the anticipated fire severity;
                                      • c. the ability of a structure to resist the spread of fire and smoke; and
                                      • d. the consequential danger to people in and around the building.
                                        0.27 A wide variety of measures could be considered and incorporated to a greater or lesser extent, as appropriate in the circumstances. These include:
                                      • a. the adequacy of means to prevent fire;
                                      • b. early fire warning by an automatic detection and warning system;
                                      • c. the standard of means of escape;
                                      • d. provision of smoke control;
                                      • e. control of the rate of growth of a fire;
                                      • f. the adequacy of the structure to resist the effects of a fire;
                                      • g. the degree of fire containment;
                                      • h. fire separation between buildings or parts of buildings;
                                      • i. the standard of active measures for fire extinguishment or control;
                                      • j. facilities to assist the fire and rescue service;
                                      • k. the availability of powers to require staff training in fire safety and fire routines;
                                      • l. consideration of the availability of any continuing control under other legislation that could ensure continued maintenance of such systems; and
                                      • m. management.
                                        0.28 It is possible to use quantitative techniques to evaluate risk and hazard. Some factors in the measures listed above can be given numerical values in some circumstances. The assumptions made when quantitative methods are used need careful assessment.

                                      Buildings of special architectural or historic interest

                                      0.29 Some variation of the provisions set out in this document may also be appropriate where Part B applies to existing buildings, particularly in buildings of special architectural or historic interest, where adherence to the guidance in this document might prove unduly restrictive. In such cases it would be appropriate to take into account a range of fire safety features, some of which are dealt with in this document, and some of which are not addressed in any detail, and to set these against an assessment of the hazard and risk peculiar to the particular case.

                                      • Diagram1- Means of escape form dwellinghouses Diagram1 - Means of escape form dwellinghouses
                                      • Diagram 2 - Alternative arrangements for final exits Diagram 2 - Alternative arrangements for final exits
                                      • Diagram 3 - Fire separation in houses with more than one floor over 4.5m above ground level Diagram 3 - Fire separation in houses with more than one floor over 4.5m above ground level
                                      • Diagram 4 - Ground or basement storey exit into an enclosed space Diagram 4 - Ground or basement storey exit into an enclosed space.
                                      • Diagram 5 - Gallery floors with no alternative exit
                                      • Diagram 6 - Alternative cavity barrier arrangements in roof space over protected stairway in a house with a floor more than 4.5m above ground level Diagram 6 - Alternative cavity barrier arrangements in roof space over protected stairway in a house with a floor more than 4.5m above ground level
                                      • Diagram 7 - Fire resistance of areas adjacent to external stairs Diagram 7 - Fire resistance of areas adjacent to external stairs
                                      • Diagram 8 - Lighting diffuser in relation to ceiling Diagram 8 - Lighting diffuser in relation to ceiling
                                      • Diagram 9 - Layout restrictions on Class 3 plastice rooflights, TP(b) rooflights and TP(b) lighting diffusers Diagram 9 - Layout restrictions on Class 3 plastice rooflights, TP(b) rooflights and TP(b) lighting diffusers
                                      • Diagram 10 - Separation between garage and dwellinghouse Diagram 10 - Separation between garage and dwellinghouse
                                      • Diagram 11 - Junction of compartment wall with roof Diagram 11 - Junction of compartment wall with roof
                                      • Diagram 12 - Interrupting concealed spaces (cavities) Diagram 12 - Interrupting concealed spaces (cavities)
                                      • Diagram 13 - Cavity walls excluded from provisions for cavity barriers Diagram 13 - Cavity walls excluded from provisions for cavity barriers
                                      • Diagram 14 - Pipes penetrating structure Diagram 14 - Pipes penetrating structure
                                      • Diagram 15 - Enclosure for drainage or water supply pipes Diagram 15 - Enclosure for drainage or water supply pipes
                                      • Diagram 16 - Fules penetrating compartment walls or floors Diagram 16 - Fules penetrating compartment walls or floors
                                      • Diagram 17 - Relevant boundary Diagram 17 - Relevant boundary
                                      • Diagram 18 - Notional boundary Diagram 18 - Notional boundary
                                      • Diagram 19 - Status of combustible surface material as unprotected area Diagram 19 - Status of combustible surface material as unprotected area
                                      • Diagram 20 - Unprotected areas which may be disregarded in assessing the separation distances from the boundry Diagram 20 - Unprotected areas which may be disregarded in assessing the separation distances from the boundry
                                      • Diagram 21 - The effect of a conopy on separation distance Diagram 21 - The effect of a conopy on separation distance
                                      • Diagram 22 - Permitted unprotected areas for Method 1 Diagram 22 - Permitted unprotected areas for Method 1
                                      • Diagram 23 - Limitations on spacing and size of plastic rooflights having a Class 3 (National class) or Class D-s3, d2 (European class) or TP(b) lower surface Diagram 23 - Limitations on spacing and size of plastic rooflights having a Class 3 (National class) or Class D-s3, d2 (European class) or TP(b) lower surface
                                      • Diagram 24 - Turning facilities Diagram 24 - Turning Facilities
                                      • Table 1 - Classification of linings Table 1 - Classification of linings
                                      • Table 3 - Maximum nominal internal diameter of pipes passing through a fire separating element Table 3 - Maximum nominal internal diameter of pipes passing through a fire separating element
                                      • Table 3 - Maximum nominal internal diameter of pipes passing through a fire separating element Table 3 - Maximum nominal internal diameter of pipes passing through a fire separating element
                                      • Table 4 - Permitted unprotected areas for Method 2 Table 4 - Permitted unprotected areas for Method 2
                                      • Table 5 - Limitations on rood coverings Table 5 - Limitations on rood coverings
                                      • Table 6- Class 3 (National class) or Class D-s3, d2 (eurpean class) plstic rooflights - limitations on use and boundary distance Table 6- Class 3 (National class) or Class D-s3, d2 (eurpean class) plstic rooflights - limitations on use and boundary distance
                                      • Table 7 - TP (a) and TP (b) plastic rooflights- limitations on use and boundary distance Table 7 - TP (a) and TP (b) plastic rooflights- limitations on use and boundary distance
                                      • Table A8 - Typical performance ratings of some generic materails and products Table A8 - Typical performance ratings of some generic materails and products
                                      • Table A1 - Specific provisions of test for fire resistance of elements of structure etc Table A1 - Specific provisions of test for fire resistance of elements of structure etc
                                      • Table A1 continued Table A1 continued
                                      • Table A2 - Minimum periods of fire resistance for dwellinghouses Table A2 - Minimum periods of fire resistance for dwellinghouses
                                      • Table A3 - Limitations on fire - protecting suspended ceilings (see Table A1, Note 4) Table A3 - Limitations on fire - protecting suspended ceilings (see Table A1, Note 4)
                                      • Table A4 - Limitations on the use of uninsulated glazed elements on escape routes Table A4 - Limitations on the use of uninsulated glazed elements on escape routes
                                      • Table A5 - Notional designations of roof coverings Table A5 - Notional designations of roof coverings
                                      • Table A6 - Use and definitions of non-combustible materials Table A6 - Use and definitions of non-combustible materials
                                      • Table A7 - Use and definitions of materails of limited combustibillty Table A7 - Use and definitions of materails of limited combustibillty
                                      • Table A8 - Typical performance ratings of some generic materails and products Table A8 - Typical performance ratings of some generic materails and products
                                      • Table B1 Provision for fire doors Table B1 Provision for fire doors
                                      • Table  C1 - Height of top storey in building Table C1 - Height of top storey in building
                                      • Table D1 - Classification of Purpose Groups Table D1 - Classification of Purpose Groups