site wide search

B1 – Fire Safety


The Approved Documents are ‘standard’ ways of getting Building Regulations approval. There are other ways. see more

If you follow the principles and rules given in the documents you can be sure that they will be approved. Of course you don’t have to use the Approved Documents, as the Regulations make clear:

Approved Documents are intended to provide guidance for some of the more common building situations. However, there may well be alternative ways of achieving compliance with the requirements. Thus there is no obligation to adopt any particular solution contained in an Approved Document if you prefer to meet the relevant requirement in some other way.

In fact the Approved Documents are a bit of a mishmash of traditional ‘rules of thumb’ and technical standards and they have gaping holes in them. Whereas, for instance, there are many pages on how to construct traditional masonry walls, there is nothing about timber frame construction except the odd reference to British standards.

See our page on timber frame design

They are also struggling to keep up with the times. If the Passivhaus Standard or zero energy new house building is introduced at some point then whole swathes of the Approved Documents will need rewriting because many of the constructional principles are based on quite low levels of insulation.

There are other ways of satisfying the regulations. For instance they make copious references to BS, BS EN and BS EN ISO standards which may be another way of fulfilling the criteria. It is even possible in some very rare cases to prove that something works by building it first and then testing it afterwards (though this is not for the faint hearted).

Although a self builder cannot be expected to understand all the building regulations, it often pays to have a grasp of what is involved, especially if last minutes changes need to be made to construction details.

The full official set of Approved Documents is available HERE.

The full official Approved document B1 is available HERE

Below is an edited extract from Approved Document, B: Fire safety, with notes for self builders. The purpose is to draw attention to the main aspects of the document. If in doubt check the full Approved Document B.

 General introduction: Fire safety


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.


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

Sprinklers are now mandatory in new Welsh houses. See our page on 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 ( 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:

  1. the anticipated probability of a fire occurring;
  2. the anticipated fire severity;
  3. the ability of a structure to resist the spread of fire and smoke; and
  4. 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:

  1. the adequacy of means to prevent fire;
  2. early fire warning by an automatic detection and warning system;
  3. the standard of means of escape;
  4. provision of smoke control;
  5. control of the rate of growth of a fire;
  6. the adequacy of the structure to resist the effects of a fire;
  7. the degree of fire containment;
  8. fire separation between buildings or parts of buildings;
  9. the standard of active measures for fire extinguishment or control;
  10. facilities to assist the fire and rescue service;
  11. the availability of powers to require staff training in fire safety and fire routines;
  12. consideration of the availability of any continuing control under other legislation that could ensure continued maintenance of such systems; and
  13. 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.

Section 1: Fire detection and fire alarm systems


1.1      Provisions are made in this section for suitable arrangements to be made in dwellinghouses to give early warning in the event of fire.


1.2      The installation of smoke alarms, or automatic fire detection and alarm systems can significantly increase the level of safety by automatically giving an early warning of fire. The following guidance is appropriate for most dwellinghouses. However, where it is known that the occupants of a proposed dwellinghouse are at a special risk from fire, it may be more appropriate to provide a higher standard of protection, e.g. additional detectors.

1.3      All new dwellinghouses should be provided with a fire detection and fire alarm system in accordance with the relevant recommendations of BS 5839-6:2004 to at least a Grade D Category LD3 standard.

1.4      The smoke and heat alarms should be mains-operated and conform to BS EN 14604: 2005, Smoke alarm devices or BS 5446-2:2003, Fire detection and fire alarm devices for dwellinghouses, Part 2 Specification for heat alarms, respectively. They should have a standby power supply, such as a battery (either rechargeable or non-rechargeable) or capacitor. More information on power supplies is given in clause 15 of BS 5839-6:2004.

Note: BS EN 14604 covers smoke alarms based on ionization chamber smoke detectors and optical (photo-electric) smoke detectors. The different types of detector respond differently to smouldering and fast-flaming fires. Either type of detector is generally suitable. However, the choice of detector type should, if possible, take into account the type of fire that might be expected and the need to avoid false alarms. Optical detectors tend to be less affected by low levels of ‘invisible’ particles, such as fumes from kitchens, that often cause false alarms. Accordingly, they are generally more suitable than ionization chamber detectors for installation in circulation spaces adjacent to kitchens.

Large houses

1.5      A dwellinghouse is regarded as large if it has more than one storey and any of those storeys exceed 200m².

1.6      A large dwellinghouse of 2 storeys (excluding basement storeys) should be fitted with a fire detection and fire alarm system of Grade B category LD3 as described in BS 5839-6:2004.

1.7     A large dwellinghouse of 3 or more storeys (excluding basement storeys) should be fitted with a Grade A Category LD2 system as described in BS 5839-6:2004, with detectors sited in accordance with the recommendations of BS 5839-1:2002 for a Category L2 system.

Material alterations

1.8     Where new habitable rooms are provided above the ground floor level, or where they are provided at ground floor level and there is no final exit from the new room, a fire detection and fire alarm system should be installed. Smoke alarms should be provided in the circulation spaces of the dwellinghouse in accordance with paragraphs 1.10 to 1.18 to ensure that any occupants of the new rooms are warned of any fire that may impede their escape.

Sheltered housing

1.9     The detection equipment in a sheltered housing scheme with a warden or supervisor should have a connection to a central monitoring point (or alarm receiving centre) so that the person in charge is aware that a fire has been detected in one of the dwellinghouses and can identify the dwellinghouse concerned. These provisions are not intended to be applied to the common parts of a sheltered housing development, such as communal lounges, or to sheltered accommodation in the Institutional or Other residential purpose groups (see Approved Document B Volume 2).

Positioning of smoke and heat alarms

1.10   Detailed guidance on the design and installation of fire detection and alarm systems in dwellinghouses is given in BS 5839-6:2004. However, the following guidance is appropriate to most common situations.

1.11   Smoke alarms should normally be positioned in the circulation spaces between sleeping spaces and places where fires are most likely to start (e.g. kitchens and living rooms) to pick up smoke in the early stages of a fire.

1.12   There should be at least one smoke alarm on every storey of a dwellinghouse.

1.13   Where the kitchen area is not separated from the stairway or circulation space by a door, there should be a compatible interlinked heat detector or heat alarm in the kitchen, in addition to whatever smoke alarms are needed in the circulation space(s).

1.14    Where more than one alarm is installed they should be linked so that the detection of smoke

or heat by one unit operates the alarm signal in all of them. The manufacturers’ instructions about the maximum number of units that can be linked should be observed.

1.15    Smoke alarms/detectors should be sited so that:

  1. there is a smoke alarm in the circulation space within 7.5m of the door to every habitable room;
  2. they are ceiling-mounted and at least 300mm from walls and light fittings (unless, in the case of light fittings, there is test evidence to prove that the proximity of the light fitting will not adversely affect the efficiency of the detector). Units designed for wall-mounting may also be used provided that the units are above the level of doorways opening into the space and they are fixed in accordance with manufacturers’ instructions; and
  3. the sensor in ceiling-mounted devices is between 25mm and 600mm below the ceiling (25-150mm in the case of heat detectors or heat alarms).

Note: This guidance applies to ceilings that are predominantly flat and horizontal.

1.16    It should be possible to reach the smoke alarms to carry out routine maintenance, such as testing and cleaning, easily and safely. For this reason smoke alarms should not be fixed over a stair or any other opening between floors.

1.17    Smoke alarms should not be fixed next to or directly above heaters or air-conditioning outlets. They should not be fixed in bathrooms, showers, cooking areas or garages, or any other place where steam, condensation or fumes could give false alarms.

1.18    Smoke alarms should not be fitted in places that get very hot (such as a boiler room) or very cold (such as an unheated porch). They should not be fixed to surfaces which are normally much warmer or colder than the rest of the space, because the temperature difference might create air currents which move smoke away from the unit.

Power supplies

1.19    The power supply for a smoke alarm system should be derived from the dwellinghouse’s mains electricity supply. The mains supply to the smoke alarm(s) should comprise a single independent circuit at the dwellinghouse’s main distribution board (consumer unit) or a single regularly used local lighting circuit. This has the advantage that the circuit is unlikely to be disconnected for any prolonged period. There should be a means of isolating power to the smoke alarms without isolating the lighting.

see our page on Electrics

1.20   The electrical installation should comply with Approved Document P (Electrical safety).

1.21   Any cable suitable for domestic wiring may be used for the power supply and interconnection to smoke alarm systems. It does not need any particular fire survival properties except in large houses (BS 5839-6:2004 specifies fire resisting cables for Grade A and B systems). Any conductors used for interconnecting alarms (signalling) should be readily distinguishable from those supplying mains power, e.g. by colour coding.

Note: Mains-powered smoke alarms may be interconnected using radio-links, provided that this does not reduce the lifetime or duration of any standby power supply below 72 hours. In this case, the smoke alarms may be connected to separate power circuits (see paragraph 1.19)

1.22   Other effective options exist and are described in BS 5839-1:2002 and BS 5839-6:2004. For example, the mains supply may be reduced to extra low voltage in a control unit incorporating a standby trickle-charged battery, before being distributed at that voltage to the alarms.

Design and installation of systems

1.23   It is essential that fire detection and fire alarm systems are properly designed, installed and maintained. Where a fire alarm system is installed, an installation and commissioning certificate should be provided. Third party certification schemes for fire protection products and related services are an effective means of providing the fullest possible assurances, offering a level of quality, reliability and safety.

1.24   A requirement for maintenance cannot be made as a condition of passing plans by the Building Control Body. However, the attention of developers and builders is drawn to the importance of providing the occupants with information on the use of the equipment, and on its maintenance (or guidance on suitable maintenance contractors). See paragraph 0.11.

Note: BS 5839-1 and BS 5839-6 recommend that occupiers should receive the manufacturers’ instructions concerning the operation and maintenance of the alarm system.

Section 2: Means of escape


see our page on Design it Yourself

2.1      The means of escape from a typical one or two storey dwellinghouse is relatively simple to provide. Few provisions are specified in this document beyond ensuring that means are provided for giving early warning in the event of fire (see Section 1) and that suitable means are provided for emergency egress from each storey via windows or doors.

With increasing height more complex provisions are needed because emergency egress through upper windows becomes increasingly hazardous. It is then necessary to protect the internal stairway. If there are floors more than 7.5m above ground level, the risk that the stairway will become impassable before occupants of the upper parts of the dwellinghouse have escaped is appreciable, and an alternative route from those parts should be provided. See Diagram 1.

Note: Ground level is explained in Appendix C, Diagram C1.

2.2      In providing any kind of fire protection in houses 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.

Provisions for escape from the ground storey

2.3      Except for kitchens, all habitable rooms in the ground storey should either:

  1. open directly onto a hall leading to the entrance or other suitable exit; or
  2. be provided with a window (or door) which complies with paragraph 2.8.

Note: See also General Provisions.

Provisions for escape from upper floors not more than 4.5m above ground level

see our page on Staircase Design

2.4      Except for kitchens, all habitable rooms in the upper storey(s) of a dwellinghouse served by only one stair should be provided with:

  1. a window (or external door) which complies with paragraph 2.8; or
  2. direct access to a protected stairway (as described in 2.6 (a) or (b)).

Note: A single window can be accepted to serve two rooms provided both rooms have their own access to the stairs. A communicating door between the rooms should also be provided so that it is possible to gain access to the window without passing through the stair enclosure.

Note: See also General Provisions.

Provisions for escape from upper floors more than 4.5m above ground level

2.5     The provisions described in 2.6 and 2.7 need not be followed if the dwellinghouse has more than one internal stairway, which afford effective alternative means of escape and are physically separated from each other.

Note: The necessary degree of separation is a matter of judgement, e.g. stairs may be separated by fire-resisting construction or by a number of rooms.

Dwellinghouses with one floor more than 4.5m above ground level

2.6     The dwellinghouse may either have a protected stairway as described in (a) below, or the top floor can be separated and given its own alternative escape route as described in (b).

  1. The upper storeys (those above ground storey) should be served by a protected stairway (protected at all levels) which should either:i. extend to a final exit, see Diagram 2(a); or
    ii.  give access to at least two escape routes at ground level, each delivering to final exits and separated from each other by fire-resisting construction and fire doors, see Diagram 2(b); or
  2. The top storey should be separated from the lower storeys by fire-resisting construction and be provided with an alternative escape route leading to its own final exit. See Diagram 3.

Note: See also General Provisions.

Dwellinghouses with more than one floor over 4.5m above ground level

2.7     Where a dwellinghouse has two or more storeys with floors more than 4.5m above ground level (typically a dwellinghouse of four or more storeys) then, in addition to meeting the provisions in paragraph 2.6:

  1. an alternative escape route should be provided from each storey or level situated 7.5m or more above ground level. Where the access to the alternative escape route is via:
    i.    the protected stairway to an upper storey; or
    ii.   a landing within the protected stairway enclosure to an alternative escape route on the same storey; then
    iii.  the protected stairway at or about 7.5m above ground level should be separated from the lower storeys or levels by fire- resisting construction, see Diagram 3; or
  2. the dwellinghouse should be fitted throughout with a sprinkler system designed and installed in accordance with BS 9251:2005.

Note: See also General Provisions.

General provisions

Emergency egress windows and external doors

2.8      Any window provided for emergency egress purposes and any external door provided for escape should comply with the following conditions:

  1. the window should have an unobstructed openable area that is at least 0.33m² and at least 450mm high and 450mm wide (the route through the window may be at an angle rather than straight through). The bottom of the openable area should be not more than 1100mm above the floor; and
  2. see our page on Basements

    the window or door should enable the person escaping to reach a place free from danger from fire. This is a matter for judgement in each case, but, in general, a courtyard or back garden from which there is no exit other than through other buildings would have to be at least as deep as the dwellinghouse is high to be acceptable, see Diagram 4.

Note 1: Approved Document K Protection from falling, collision and impact specifies a minimum guarding height of 800mm, except in the case of a window in a roof where the bottom of the opening may be 600mm above the floor.

Note 2: Locks (with or without removable keys) and stays may be fitted to egress windows, subject to the stay being fitted with a release catch, which may be child resistant.

Note 3: Windows should be designed such that they will remain in the open position without needing to be held by a person making their escape.

Inner rooms

2.9      A room whose only escape route is through another room is termed an inner room and is  at risk if a fire starts in that other room (access room). This situation may arise with open-plan layouts and galleries. Such an arrangement is only acceptable where the inner room is:

  1. a kitchen;
  2. a laundry or utility room;
  3. a dressing room;
  4. a bathroom, WC, or shower room;
  5. any other room on a floor, not more than 4.5m above ground level, provided with an emergency egress window which complies with paragraph 2.8; or
  6. a gallery which complies with paragraph 2.12.

Note: A room accessed only via an inner room (an inner-inner room) may be acceptable if it complies with the above, not more than one door separates the room from an interlinked smoke alarm and none of the access rooms is a kitchen.

Balconies and flat roofs

2.10   A flat roof forming part of a means of escape should comply with the following provisions:

  1. the roof should be part of the same building from which escape is being made;
  2. the route across the roof should lead to a storey exit or external escape route; and
  3. the part of the roof forming the escape route and its supporting structure, together with any opening within 3m of the escape route, should provide 30 minutes fire resistance (see Appendix A, Table A1).

see our page on Balconies

2.11   Where a balcony or flat roof is provided for escape purposes guarding may be needed, in which case it should meet the provisions in Approved Document K Protection from falling, collision and impact.


2.12    A gallery should be provided with an alternative exit or, where the gallery floor is not more than 4.5m above ground level, an emergency egress window which complies with paragraph 2.8. Alternatively, where the gallery floor is not provided with an alternative exit or escape window, it should comply with the following;

  1. the gallery should overlook at least 50% of the room below (see Diagram 5);
  2. the distance between the foot of the access stair to the gallery and the door to the room containing the gallery should not exceed 3m;
  3. the distance from the head of the access stair to any point on the gallery should not exceed 7.5m; and
  4. any cooking facilities within a room containing a gallery should either:
    i.  be enclosed with fire-resisting construction; or
    ii. be remote from the stair to the gallery and positioned such that they do not prejudice the escape from the gallery.


2.13   Because of the risk that a single stairway may be blocked by smoke from a fire in the basement or ground storey, if the basement storey contains any habitable room, the dwellinghouse should be provided with either:

  1. an external door or window suitable for egress from the basement (see paragraph 2.8); or
  2. a protected stairway leading from the basement to a final exit.

Cavity barriers

2.14   Cavity barriers should be provided above the enclosures to a protected stairway in a dwellinghouse with a floor more than 4.5m above ground level (see Diagram 6).

External escape stairs

2.15    Where an external escape stair is provided, it should meet the following provisions:

  1. All doors giving access to the stair should be fire-resisting, except that a fire-resisting door is not required at the head of any stair leading downwards where there is only one exit from the building onto the top landing.
  2. Any part of the external envelope of the building within 1800mm of (and 9m vertically below) the flights and landings of an external escape stair should be of fire-resisting construction, except that the 1800mm dimension may be reduced to 1100mm above the top level of the stair if it is not a stair up from a basement to ground level (see Diagram 7).
  3. There is protection by fire-resisting construction for any part of the building (including any doors) within 1800mm of the escape route from the stair to a place of safety, unless there is a choice of routes from the foot of the stair that would enable the people escaping to avoid exposure to the effects of the fire in the adjoining building.
  4. Any stair more than 6m in vertical extent is protected from the effects of adverse weather conditions. (This should not be taken to imply a full enclosure. Much will depend on the location of the stair and the degree of protection given to the stair by the building itself).
  5. Glazing in areas of fire-resisting construction mentioned above should also be fire-resisting (integrity but not insulation) and fixed shut.

Air circulation systems in houses with a floor more than 4.5m above ground level

2.16   Air circulation systems which circulate air within an individual dwellinghouse with a floor more than 4.5m above ground level should meet the guidance given in paragraph 2.17. Where ventilation ducts pass through compartment walls into another building then the guidance given in Approved Document B Volume 2 should be followed.

2.17   With these types of systems, the following precautions are needed to avoid the possibility of the system allowing smoke or fire to spread into a protected stairway:

  1. Transfer grilles should not be fitted in any wall, door, floor or ceiling enclosing a protected stairway.
  2. Any duct passing through the enclosure to a protected stairway or entrance hall should be of rigid steel construction and all joints between the ductwork and the enclosure should be fire-stopped.
  3. Ventilation ducts supplying or extracting air directly to or from a protected stairway, should not serve other areas as well.
  4. Any system of mechanical ventilation which recirculates air and which serves both the stairway and other areas should be designed to shut down on the detection of smoke within the system.
  5. A room thermostat for a ducted warm air heating system should be mounted in the living room, at a height between 1370mm and 1830mm, and its maximum setting should not exceed 27ºC.

see our page on Disabled Access

Passenger lifts

2.18   Where a passenger lift is provided in the dwellinghouse and it serves any floor more than 4.5m above ground level, it should either be located in the enclosure to the protected stairway (see paragraph 2.6) or be contained in a fire- resisting lift shaft.

Work on existing houses

see our page on Windows

Replacement windows

2.19   Regulation 4(1) requires that all “building work”, as defined by Regulation 3, complies with the applicable requirements of Schedule 1 to the Building Regulations. The definition of building work in Regulation 3(1) includes the provision or extension of a “controlled service or fitting” in or in connection with a building. The definition of controlled service or fitting is given in Regulation 2(1), and includes a replacement window.

Where windows are to be replaced (but not where they are to be repaired only, as repair work to windows does not fall within the definition of building work) the replacement work should comply with the requirements of Parts L and N of Schedule 1. In addition, the building should not have a lesser level of compliance, after the work has been completed, with other applicable Parts of Schedule 1.

For the purposes of Part B1, where a window is located such that, in a new dwellinghouse, an escape window would be necessary and the window is of sufficient size that it could be used for the purposes of escape then:

  1. the replacement window opening should be sized to provide at least the same potential for escape as the window it replaces; or
  2. where the original window is larger than necessary for the purposes of escape, the window opening could be reduced down to the minimum specified in paragraph 2.8.

Note: Part B3 makes provisions for cavity barriers around window openings in some forms of construction. Where windows are replaced it may be necessary to consider if adequate protection is maintained.

Material alterations

2.20    Paragraph 0.20 sets out the requirements relating to material alterations. What constitutes reasonable provision where undertaking material alterations would depend on the circumstances in the particular case and would need to take account of historic value (see paragraph 0.29). Possible ways of satisfying the requirements include:

a.  Smoke alarms

Where new habitable rooms are provided then smoke alarms should be provided in accordance with paragraph 1.8.

b.  Loft conversions

Where a new storey is to be added by converting an existing roof space, the provisions for escape need to be considered throughout the full extent of the escape route. For example, a loft conversion to a two-storey house will result in the need to protect the stairway (by providing fire-resisting doors and partitions) where previously no protection may have existed (see paragraph 2.6a).

Note: If it is considered undesirable to replace existing doors (e.g. if they are of historical or architectural merit) it may be possible to retain the doors or upgrade them to an acceptable standard.

Note: Where an ‘open-plan’ arrangement exists at ground level it may be necessary to provide a new partition to enclose the escape route (see Diagram 2).

Alternatively, it may be possible to provide sprinkler protection to the open-plan area, in conjunction with a fire-resisting partition and door (E20), in order to separate the ground floor from the upper storeys. This door should be so arranged to allow the occupants of the loft room to access an escape window at first floor level (in accordance with paragraph 2.8) in the event of a fire in the open-plan area. Cooking facilities should be separated from the open-plan area with fire-resisting construction.

Section 3: Wall and ceiling linings

Classification of linings

3.1      Subject to the variations and specific provisions described in paragraphs 3.2 to 3.16, the surface linings of walls and ceilings should meet the following classifications:

Definition of walls

3.2      For the purpose of the performance of wall linings, a wall includes:

  1. the surface of glazing (except glazing in doors); and
  2. any part of a ceiling which slopes at an angle of more than 70º to the horizontal.But a wall does not include:
  3. doors and door frames;
  4. window frames and frames in which glazing is fitted;
  5. architraves, cover moulds, picture rails, skirtings and similar narrow members; or
  6. fireplace surrounds, mantle shelves and fitted furniture.

Definition of ceilings

3.3      For the purposes of the performance of ceiling linings, a ceiling includes:

  1. the surface of glazing;
  2. any part of a wall which slopes at an angle of 70º or less to the horizontal;
  3. the underside of a gallery; and
  4. the underside of a roof exposed to the room below.But a ceiling does not include:
  5. trap doors and their frames;
  6. the frames of windows or rooflights (see Appendix E) and frames in which glazing is fitted; or
  7. architraves, cover moulds, picture rails, exposed beams and similar narrow members.

Variations and special provisions


3.4     Parts of walls in rooms may be of a poorer performance than specified in paragraph 3.1 (but not poorer than Class 3 (National class) or Class D-s3, d2 (European class) provided the total area of those parts in any one room does not exceed one half of the floor area of the room, subject to a maximum of 20m².

Fire-protecting suspended ceilings

3.5     A suspended ceiling can contribute to the overall fire resistance of a floor/ceiling assembly. Such a ceiling should satisfy paragraph 3.1. It should also meet the provisions of Appendix A, Table A3.

Fire-resisting ceilings

3.6     Cavity barriers are needed in some concealed floor or roof spaces (see Section 6), however, this need can be reduced by the use of a fire-resisting ceiling below the cavity.


3.7     Rooflights should meet the relevant classification in 3.1. However, plastic rooflights with at least a Class 3 rating may be used where 3.1 calls for a higher standard, provided the limitations in Table 2 and in Table 6 are observed.

Note: No guidance is currently possible on the performance requirements in the European fire tests as there is no generally accepted test and classification procedure.

Thermoplastic materials


3.8     Thermoplastic materials (see Appendix A, paragraph 17) which cannot meet the performance given in Table 1, can nevertheless be used in windows, rooflights and lighting diffusers in suspended ceilings if they comply with the provisions described in paragraphs 3.10 to 3.14. Flexible thermoplastic material may be used in panels to form a suspended ceiling if it complies with the guidance in paragraph 3.16. The classifications used in paragraphs 3.11 to 3.16, Table 2 and Diagram 9 are explained in Appendix A, paragraph 20.

Note: No guidance is currently possible on the performance requirements in the European fire tests as there is no generally accepted test and classification procedure.

Windows and internal glazing

3.9      External windows to rooms (though not to circulation spaces) may be glazed with thermoplastic materials, if the material can be classified as a TP(a) rigid product.

Internal glazing should meet the provisions in paragraph 3.1.


  1. A ‘wall’ does not include glazing in a door (see paragraph 3.2).
  2. Attention is drawn to the guidance on the safety of glazing in Approved Document N Glazing – safety in relation to impact, opening and cleaning.


3.10 Rooflights to rooms and circulation spaces (with the exception of protected stairways) may be constructed of a thermoplastic material if:

  1. the lower surface has a TP(a) (rigid) or TP(b) classification
  2. the size and disposition of the rooflights accords with the limits in Table 2 and with the guidance to B4 in Table 7.

Lighting diffusers

3.11    The following provisions apply to lighting diffusers which form part of a ceiling. They are not concerned with diffusers of light fittings which are attached to the soffit of, or suspended beneath a ceiling (see Diagram 8).

Lighting diffusers are translucent or open- structured elements that allow light to pass through. They may be part of a luminaire or used below rooflights or other sources of light.

3.12    Thermoplastic lighting diffusers should not be used in fire-protecting or fire-resisting ceilings, unless they have been satisfactorily tested as part of the ceiling system that is to be used to provide the appropriate fire protection.

3.13   Subject to the above paragraphs, ceilings to rooms and circulation spaces (but not protected stairways) may incorporate thermoplastic lighting diffusers if the following provisions are observed:

  1. Wall and ceiling surfaces exposed within the space above the suspended ceiling (other than the upper surfaces of the thermoplastic panels) should comply with the general provisions of paragraph 3.1, according to the type of space below the suspended ceiling;
  2. If the diffusers are of classification TP(a) (rigid), there are no restrictions on their extent;
  3. If the diffusers are of classification TP(b), they should be limited in extent as indicated in Table 2 and Diagram 9.

Suspended or stretched-skin ceilings

3.14   The ceiling of a room may be constructed either as a suspended or stretched-skin membrane from panels of a thermoplastic material of the TP(a) flexible classification, provided that it is not part of a fire-resisting ceiling. Each panel should not exceed 5m² in area and should be supported on all its sides.

Section 4: Loadbearing elements of structure


see our page on Main Structure

4.1      Premature failure of the structure can be prevented by provisions for loadbearing elements of structure to have a minimum standard of fire resistance, in terms of resistance to collapse or failure of loadbearing capacity. The purpose in providing the structure with fire resistance is threefold, namely:

  1. to minimise the risk to the occupants, some of whom may be unable to make their own escape if they have become trapped or injured;
  2. to reduce the risk to firefighters, who may be engaged in search or rescue operations; and
  3. to reduce the danger to people in the vicinity of the building, who might be hurt by falling debris or as a result of the impact of the collapsing structure on other buildings.

Fire resistance standard

4.2      Elements of structure such as structural frames, beams, columns, loadbearing walls (internal and external), floor structures and gallery structures should have at least the fire resistance given in Appendix A, Table A1.

Application of the fire resistance standards for loadbearing elements

4.3      The measures set out in Appendix A include provisions to ensure that where one element of structure supports or gives stability to another element of structure, the supporting

element has no less fire resistance than the other element (see notes to Table A2). The measures also provide for elements of structure that are common to more than one building or compartment, to be constructed to the standard of the greater of the relevant provisions. Special provisions about fire resistance of elements of structure in single storey buildings are also given and there are concessions in respect of fire resistance of elements of structure in basements where at least one side of the basement is open at ground level.

Exclusions from the provisions for elements of structure

4.4      The following are excluded from the definition of element of structure for the purposes of these provisions:

  1. structure that only supports a roof, unless:
    i.  the roof performs the function of a floor, such as a roof terrace, or as a means of escape (see Section 2), or
    ii.  the structure is essential for the stability of an external wall which needs to have fire resistance; and
  2. the lowest floor of the building.

Additional guidance

4.5     Guidance in other sections of this Approved Document may also apply if a loadbearing wall is:

  1. a compartment wall (this includes a wall common to two buildings), (see Section 5);
  2. a wall between a dwellinghouse and an integral garage, (see Section 5, paragraph 5.4);
  3. protecting a means of escape, (see Section 2); or
  4. an external wall, (see Sections 8 to 9).

4.6     If a floor is also a compartment floor, see Section 5.

Floors in loft conversions

4.7     In altering an existing two-storey single family dwellinghouse to provide additional storeys, the provisions in this Approved Document are for the floor(s), both old and new, to have the full 30 minute standard of fire resistance shown in Appendix A, Table A1. However, provided that the following conditions are satisfied, namely:

  1. only one storey is being added;
  2. the new storey contains no more than 2 habitable rooms; and
  3. the total area of the new storey does not amount to more than 50m2;

then the existing first floor construction may be accepted if it has at least a modified 30 minute standard of fire resistance, in those places where the floor separates only rooms (and not circulation spaces).


  1. The ‘modified 30 minute’ standard satisfies the test criteria for the full 30 minutes in respect of loadbearing capacity, but allows reduced performances for integrity and insulation (see Appendix A, Table A1, item 3(a)).
  2. A floor which forms part of the enclosure to the circulation space between the loft conversion and the final exit needs a full 30 minute standard.

Conversion to flats

4.8     Where an existing dwellinghouse or other building is converted into flats the guidance in Volume 2 should be followed.

Section 5: Compartmentation


5.1      The spread of fire within a building can be restricted by sub-dividing it into compartments separated from one another by walls and/or floors of fire-resisting construction. The object is twofold:

  1. to prevent rapid fire spread which could trap occupants of the building; and
  2. to reduce the chance of fires becoming large, on the basis that large fires are more dangerous, not only to occupants and fire and rescue service personnel, but also to people in the vicinity of the building. Compartmentation is complementary to provisions made in Section 2 for the protection of escape routes, and to provisions made in Sections 8 to 10 against the spread of fire between buildings.

Provision of compartmentation

5.2      Compartment walls and compartment floors should be provided in the circumstances described below, with the proviso that the lowest floor in a building does not need to be constructed as a compartment floor. Provisions for the protection of openings in compartment walls and compartment floors are given in paragraph 5.13 and Section 7.

5.3      Every wall separating semi-detached houses, or houses in terraces, should be constructed as a compartment wall and the houses should be considered as separate buildings.

5.4      If a domestic garage is attached to (or forms an integral part of) a dwellinghouse, the garage should be separated from the rest of the dwellinghouse, as shown in Diagram 10.

5.5      Where a door is provided between a dwellinghouse and the garage, the floor of the garage should be laid to fall to allow fuel spills to flow away from the door to the outside. Alternatively, the door opening should be positioned at least 100mm above garage floor level.

Construction of compartment walls and compartment floors


5.6      Every compartment wall and compartment floor should:

  1. form a complete barrier to fire between the compartments they separate; and
  2. have the appropriate fire resistance as indicated in Appendix A, Tables A1 and A2.

Note: Timber beams, joists, purlins and rafters may be built into or carried through a masonry or concrete compartment wall if the openings for them are kept as small as practicable and then fire-stopped. If trussed rafters bridge the wall, they should be designed so that failure of any part of the truss due to a fire in one compartment will not cause failure of any part of the truss in another compartment.

Compartment walls between buildings

5.7     Compartment walls that are common to two or more buildings should run the full height of the building in a continuous vertical plane. Thus adjoining buildings should only be separated by walls, not floors.

5.8     Compartment walls in a top storey beneath a roof should be continued through the roof space (see definition of compartment in Appendix E).

Junction of compartment wall or compartment floor with other walls

5.9     Where a compartment wall or compartment floor meets another compartment wall, or an external wall, the junction should maintain the fire resistance of the compartmentation. Fire-stopping should meet the provisions of paragraphs 7.12 to 7.14.

5.10   At the junction of a compartment floor with an external wall that has no fire resistance (such as a curtain wall) the external wall should be restrained at floor level to reduce the movement of the wall away from the floor when exposed to fire.

Junction of compartment wall with roof

5.11    A compartment wall should be taken up to meet the underside of the roof covering or deck, with fire-stopping where necessary at the wall/ roof junction to maintain the continuity of fire resistance. The compartment wall should also be continued across any eaves.

5.12    If a fire penetrates a roof near a compartment wall there is a risk that it will spread over the roof to the adjoining compartment. To reduce this risk either:

  1. the wall should be extended up through the roof for a height of at least 375mm above the top surface of the adjoining roof covering (see Diagram 11a). Where there is a height difference of at least 375mm between two roofs or where the roof coverings on either side of the wall are AA, AB or AC this height may be reduced to 200mm; or
  2. a zone of the roof 1500mm wide on either side of the wall should have a covering of designation AA, AB or AC. Any combustible boarding used as a substrate to the roof covering, wood wool slabs, or timber tiling battens that are carried over the compartment wall should be fully bedded in mortar or other suitable material over the width of the wall (see Diagram 11b).

Note: Double-skinned insulated roof sheeting with a thermoplastic core should incorporate a band of material of limited combustibility at least 300mm wide centred over the wall.

Openings in compartmentation

Openings in compartment walls separating buildings or occupancies

5.13   Any openings in a compartment wall which is common to two or more buildings should be limited to those for:

  1. a door which is needed to provide a means of escape in case of fire and which has the same fire resistance as that required for the wall (see Appendix B, Table B1) and is fitted in accordance with the provisions of Appendix B; and
  2. the passage of a pipe which meets the provisions in Section 7.


5.14   Information on fire doors may be found in Appendix B.

Section 6: Concealed spaces (cavities)


6.1      Concealed spaces or cavities in the construction of a building provide a ready route for smoke and flame spread e.g. in walls, floors, ceilings and roofs. As any spread is concealed, it presents a greater danger than would a more obvious weakness in the fabric of the building.

Provision of cavity barriers

6.2      Provisions are given below for cavity barriers in specified locations. The provisions necessary to restrict the spread of smoke and flames through cavities are broadly for the purpose of sub-dividing cavities, which could otherwise form a pathway around a fire separating element, and closing the edges of cavities; therefore reducing the potential for unseen fire spread. See also paragraph 2.14.

Note: These should not be confused with fire stopping details, see Sections 5 and 7.

Consideration should also be given to the construction and fixing of cavity barriers provided for these purposes and the extent to which openings in them should be protected. For guidance on these issues, see paragraphs 6.6 to 6.9 respectively.

6.3     Cavity barriers should be provided at the edges of cavities, including around openings (such as window and door openings). Additionally, cavity barriers should be provided at the junction between an external cavity wall and a compartment wall that separates buildings, see Diagram 12; and at the top of such an external cavity wall, except where the cavity wall complies with Diagram 13.

It is important to continue any compartment wall up through a ceiling or roof cavity to maintain the standard of fire resistance – therefore compartment walls should be carried up to the roof, see paragraph 5.11. It is not appropriate to complete a line of compartment walls by fitting cavity barriers above them.

Double-skinned insulated roof sheeting

6.4      Cavity barriers need not be provided between double-skinned corrugated or profiled insulated roof sheeting, if the sheeting is a material of limited combustibility; and both surfaces of the insulating layer have a surface spread of flame of at least Class 0 or 1 (National class) or Class C-s3, d2 or better (European class) (see Appendix A); and make contact with the inner and outer skins of cladding.

Note: When a classification includes “s3, d2”, this means that there is no limit set for smoke production and/or flaming droplets/particles.

Construction and fixings for cavity barriers

6.5     Every cavity barrier should be constructed to provide at least 30 minutes fire resistance and may be formed by any construction provided for another purpose if it meets the provisions for cavity barriers (see Appendix A, Table A1, item 10).

However, cavity barriers in a stud wall or partition, or provided around openings may be formed of:

  1. steel at least 0.5mm thick; or
  2. timber at least 38mm thick; or
  3. polythene-sleeved mineral wool, or mineral wool slab, in either case under compression when installed in the cavity; or
  4. calcium silicate, cement-based or gypsum- based boards at least 12mm thick.

Note: Cavity barriers provided around openings may be formed by the window or door frame if the frame is constructed of steel or timber of the minimum thickness in (a) or (b) above as appropriate.

6.6     A cavity barrier should, wherever possible, be tightly fitted to a rigid construction and mechanically fixed in position. Where this is not possible (for example, in the case of a junction with slates, tiles, corrugated sheeting or similar materials) the junction should be fire-stopped. Provisions for fire-stopping are set out in Section 7.

6.7     Cavity barriers should also be fixed so that their performance is unlikely to be made ineffective by:

  1. movement of the building due to subsidence, shrinkage or temperature change; and movement of the external envelope due to wind; and
  2. collapse in a fire of any services penetrating them; and
  3. failure in a fire of their fixings (but see note below); and
  4. failure in a fire of any material or construction which they abut. (For example, if a suspended ceiling is continued over the top of a fire- resisting wall or partition, and direct connection is made between the ceiling and the cavity barrier above the line of the wall or partition, premature failure of the cavity barrier can occur when the ceiling collapses. However, this may not arise if the ceiling is designed to provide fire resistance of 30 minutes or more.)

Note: Where cavity barriers are provided in roof spaces, the roof members to which they are fitted are not expected to have any fire resistance (for the purpose of supporting the cavity barrier(s)).

Openings in cavity barriers

6.8      Any openings in a cavity barrier should be limited to those for:

  1. doors which have at least 30 minutes fire resistance (see Appendix B, Table B1, item 1(a)) and are fitted in accordance with the provisions of Appendix B;
  2. the passage of pipes which meet the provisions in Section 7;
  3. the passage of cables or conduits containing one or more cables;
  4. openings fitted with a suitably mounted automatic fire damper; and
  5. ducts which are fire-resisting or are fitted with a suitably mounted automatic fire damper where they pass through the cavity barrier.

Section 7: Protection of openings and fire-stopping


7.1      Sections 7 and 8 make provisions for fire-separating elements and set out the circumstances in which there may be openings in them. This section deals with the protection of openings in such elements.

7.2      If a fire-separating element is to be effective, then every joint, or imperfection of fit, or opening to allow services to pass through the element, should be adequately protected by sealing or fire-stopping so that the fire resistance of the element is not impaired.

7.3      The measures in this section are intended to delay the passage of fire. They generally have the additional benefit of retarding smoke spread but the test specified in Appendix A for integrity does not directly stipulate criteria for the passage of smoke.

7.4     Consideration should also be given to the effect of services that may be built into the construction that could adversely affect its fire resistance. For instance, where downlighters, loudspeakers and other electrical accessories are installed, additional protection may be required to maintain the integrity of a wall or floor.

7.5     Detailed guidance on door openings and fire doors is given in Appendix B.

Openings for pipes

7.6     Pipes which pass through fire-separating elements (unless the pipe is in a protected shaft), should meet the appropriate provisions in alternatives A, B or C below.

Alternative A: Proprietary seals

(any pipe diameter)

7.7     Provide a proprietary sealing system which has been shown by test to maintain the fire resistance of the wall, floor or cavity barrier.

Alternative B: Pipes with a restricted diameter

7.8     Where a proprietary sealing system is not used, fire-stopping may be used around the pipe, keeping the opening as small as possible. The nominal internal diameter of the pipe should not be more than the relevant dimension given in Table 3.

Alternative C: sleeving


7.9    A pipe of lead, aluminium, aluminium alloy, fibre-cement or uPVC, with a maximum nominal internal diameter of 160mm, may be used with a sleeving of non-combustible pipe as shown in Diagram 14. The specification for non-combustible and uPVC pipes is given in the notes to Table 3.

see our page on Ventilation

Ventilation ducts, flues etc.

7.10   Air circulation systems which circulate air within an individual dwellinghouse with a floor more than 4.5m above ground level should meet the guidance given in paragraph 2.16. Where ventilation ducts pass through compartment walls into another building then the guidance given in Approved Document B Volume 2 should be followed.

7.11    If a flue or duct containing flues or appliance ventilation duct(s), passes through a compartment wall or compartment floor, or is built into a compartment wall, each wall of the flue or duct should have a fire resistance of at least half that of the wall or floor in order to prevent the by-passing of the compartmentation (see Diagram 16).


7.12   In addition to any other provisions in this document for fire-stopping:
a.   joints between fire-separating elements should be fire-stopped; and
b.  all openings for pipes, ducts, conduits or cables to pass through any part of a fire-separating element should be:
  1. kept as few in number as possible; and
  2. kept as small as practicable; and
  3. fire-stopped (which in the case of a pipe or duct should allow thermal movement).
7.13   To prevent displacement, materials used for fire-stopping should be reinforced with (or supported by) materials of limited combustibility in the following circumstances:
  1. in all cases where the unsupported span is greater than 100mm; and
  2. in any other case where non-rigid materials are used (unless they have been shown to be satisfactory by test).
7.14   Proprietary fire-stopping and sealing systems, (including those designed for service penetrations) which have been shown by test to maintain the fire resistance of the wall or other element, are available and may be used.

Other fire-stopping materials include:

•  cement mortar;
•  gypsum-based plaster;
•  cement-based or gypsum-based vermiculite/perlite mixes;
•  glass fibre, crushed rock, blast furnace slag or ceramic-based products (with or without resin binders); and
• intumescent mastics.

These may be used in situations appropriate to the particular material. Not all of them will be suitable in every situation.

Guidance on the process of design, installation and maintenance of passive fire protection is available in Ensuring Best Practice for Passive Fire Protection in Buildings(ISBN: 1 87040 919 1) produced by the Association for Specialist Fire Protection (ASFP).

Further information on the generic types of systems available, information about their suitability for different applications and guidance on test methods is given in the ASFP Red Book: Fire Stopping and Penetration Seals for the Construction Industry – the ‘Red Book’ published by the Association for Specialist Fire Protection and freely available from the ASFP website at

Section 8: Construction of external walls


see our page on wall construction

8.1   Provisions are made in this section for the external walls of the building to have sufficient fire resistance to prevent fire spread across the relevant boundary. The provisions are closely linked with those for space separation in Section 9 which sets out limits on the amount of unprotected area of wall. As the limits depend on the distance of the wall from the relevant boundary, it is possible for some or all of the walls to have no fire resistance, except for any parts which are loadbearing (see paragraph B3.iii).

External walls are elements of structure and the relevant period of fire resistance (specified in Appendix A) depends on the use, height and size of the building concerned. If the wall is 1000mm or more from the relevant boundary, a reduced standard of fire resistance is accepted in most cases and the wall only needs fire resistance from the inside.

8.2   Provisions are also made to restrict the combustibility of external walls of buildings that are less than 1000mm from the relevant boundary. This is in order to reduce the surface’s susceptibility to ignition from an external source.

In the guidance to Requirement B3, provisions are made in Section 4 for internal and external loadbearing walls to maintain their loadbearing function in the event of fire.

Fire resistance standard

8.3   The external walls of the building should have the appropriate fire resistance given in Appendix A, Table A1, unless they form an unprotected area under the provisions of Section 9.

External surfaces

see our section on external wall finishes

8.4   The external surfaces of walls within 1000mm of the relevant boundary should meet Class 0 (National Class) or Class B-s3,d2 or better (European class). The total amount of combustible material on walls more than 1000mm from the relevant boundary may be limited in practice by the provisions for space separation in Section 9 (see paragraphs 9.7 to 9.17.).

Section 9: Space separation


9.1   The provisions in this Section are based on a number of assumptions and, whilst some of these may differ from the circumstances of a particular case, together they enable a reasonable standard of space separation to be specified. The provisions limit the extent of unprotected areas in the sides of a building (such as openings and areas with a combustible surface) which will not give adequate protection against the external spread of fire from one building to another.

A roof is not subject to the provisions in this Section unless it is pitched at an angle greater than 70º to the horizontal (see definition for ‘external wall’ in Appendix E). Similarly, vertical parts of a pitched roof such as dormer windows (which taken in isolation might be regarded as a wall), would not need to meet the following provisions unless the slope of the roof exceeds 70º. It is a matter of judgement whether a continuous run of dormer windows occupying most of a steeply pitched roof should be treated as a wall rather than a roof.

9.2   The assumptions are:
  1. that the size of a fire will depend on the compartmentation of the building, so that a fire may involve a complete compartment, but will not spread to other compartments;
  2. that the intensity of the fire is related to the use of the building (i.e. purpose group), but that it can be moderated by a sprinkler system;
  3. that Residential (1 and 2) and Assembly and Recreation (5) Purpose Groups represent a greater life risk than other uses;
  4. that there is a building on the far side of the boundary that has a similar elevation to the one in question and that it is at the same distance from the common boundary; and
  5. that the amount of radiation that passes through any part of the external wall that has fire resistance may be discounted.
9.3   Where a reduced separation distance is desired (or an increased amount of unprotected area) it may be advantageous to introduce additional compartment walls and/or floors.


9.4   The use of the distance to a boundary, rather than to another building, in measuring the separation distance, makes it possible to calculate the allowable proportion of unprotected areas, regardless of whether there is a building on an adjoining site and regardless of the site of that building and the extent of any unprotected areas that it might have.

A wall is treated as facing a boundary if it makes an angle with it of 80º or less (see Diagram 17).

Usually only the distance to the actual boundary of the site needs to be considered. But, in some circumstances, when the site boundary adjoins a space where further development is unlikely, such as a road, then part of the adjoining space may be included as falling within the relevant boundary for the purposes of this section. The meaning of the term boundary is explained in Diagram 17.

Relevant boundaries

9.5   The boundary which a wall faces, whether it is the actual boundary of the site or a notional boundary, is called the relevant boundary (see Diagrams 17 and 18).

Notional boundaries

9.6   The distances to other buildings on the same site also need to be considered. This is done by assuming that there is a boundary between those buildings. This assumed boundary is called a notional boundary. The appropriate rules are given in Diagram 18.

Unprotected areas

Unprotected areas and fire resistance

9.7   Any part of an external wall which has less fire resistance than the appropriate amount given in Appendix A, Table A2, is considered to be an unprotected area.

Status of combustible surface materials as unprotected area

9.8   If an external wall has the appropriate fire resistance, but has combustible material more than 1mm thick as its external surface, then that wall is counted as an unprotected area amounting to half the actual area of the combustible material, see Diagram 19. (For the purposes of this provision, a material with a Class 0 rating (National class) or Class B-s3, d2 rating (European class) (see Appendix A, paragraphs 7 and 13) need not be counted as unprotected area.)
Note:  When a classification includes ‘s3, d2’, this means that there is no limit set for smoke production and/or flaming droplets/particles.

Small unprotected areas

9.9   Small unprotected areas in an otherwise protected area of wall are considered to pose a negligible risk of fire spread and may be disregarded. Diagram 20 shows the constraints that apply to the placing of such areas in relation to each other and to lines of compartmentation inside the building. These constraints vary according to the size of each unprotected area.


9.10   Some canopy structures would be exempt from the application of the Building Regulations by falling within Class 6 or Class 7 of Schedule 2 to the Regulations (Exempt Buildings and Work). Many others may not meet the exemption criteria and, in such cases, the provisions in this section about limits of unprotected areas could be onerous.

In the case of a canopy attached to the side of a building, provided that the edges of the canopy are at least 2m from the relevant boundary, separation distance may be determined from the wall rather than the edge of the canopy (see Diagram 21).

External walls within 1000mm of the relevant boundary

9.11   A wall situated within 1000mm from any point on the relevant boundary, including a wall coincident with the boundary, will meet the provisions for space separation if:
  1. the only unprotected areas are those shown in Diagram 20; and
  2. the rest of the wall is fire-resisting from both sides.

External walls 1000mm or more from the relevant boundary

9.12   A wall situated at least 1000mm from any point on the relevant boundary will meet the provisions for space separation if:
  1. the extent of unprotected area does not exceed that given by one of the methods referred to in paragraph 9.13; and
  2. the rest of the wall (if any) is fire-resisting.

Methods for calculating acceptable unprotected area

9.13   Two simple methods are given in this Approved Document for calculating the acceptable amount of unprotected area in an external wall that is at least 1000mm from any point on the relevant boundary. (For walls within 1000mm of the boundary see paragraph 9.11 above.)

Method 1 may be used for small residential buildings and is set out in paragraph 9.16.

Method 2 may be used for most buildings or compartments for which Method 1 is not appropriate, and is set out in paragraph 9.17.

There are other more precise methods, described in a BRE report External fire spread: Building separation and boundary distances

(BR 187, BRE 1991), which may be used instead of Methods 1 and 2. The ‘Enclosing Rectangle’ and ‘Aggregate Notional Area’ methods are included in the BRE report.

Basis for calculating acceptable unprotected area

9.14   The basis of Methods 1 and 2 was originally set out in Fire Research Technical Paper No 5, 1963. This has been reprinted as part of the BRE report referred to in paragraph 9.13. The aim is to ensure that the building is separated from the boundary by at least half the distance at which the total thermal radiation intensity received from all unprotected areas in the wall would be 12.6 kw/m2 (in still air), assuming the radiation intensity at each unprotected area is 84 kw/m2.

see our page on sprinkler systems

Sprinkler systems

9.15   If a building is fitted throughout with a sprinkler system, it is reasonable to assume that the intensity and extent of a fire will be reduced. The sprinkler system should meet the relevant recommendations of BS 9251 Sprinkler systems for residential and domestic occupancies. Code of practice. In these circumstances the boundary distance may be half that for an otherwise similar, but unsprinklered, building, subject to there being a minimum distance of 1000mm. Alternatively, the amount of unprotected area may be doubled if the boundary distance is maintained.

Note: The presence of sprinklers may be taken into account in a similar way when using the BRE report referred to in paragraph 9.14.

Method 1

9.16 This method applies only to a building, which is 1000mm or more from any point on the relevant boundary and meets the following rules for determining the maximum unprotected area, which should be read with Diagram 22:
  1. The building should not exceed 3 storeys in height (basements are not counted) or be more than 24m in length; and
  2. Each side of the building will meet the provisions for space separation if:
    i.  the distance of the side of the building from the relevant boundary; and
    ii  the extent of the unprotected area, are within the limits given in Diagram 22; and
    Note: In calculating the maximum unprotected area, any areas falling within the limits shown in Diagram 20, and referred to in paragraph 9.9, can be disregarded.
  3. Any parts of the side of the building in excess of the maximum unprotected area should be fire-resisting.

Method 2

9.17   This method applies to a dwellinghouse which is more than 1000mm from any point on the relevant boundary. The following rules for determining the maximum unprotected area should be read with Table 4.
  1. The building or compartment should not exceed 10m in height.
    Note: For any building or compartment more than 10m in height, the methods set out in the BRE report External fire spread: Building separation and boundary distances can be applied.
  2. Each side of the building will meet the provisions for space separation if either:i.   the distance of the side of the building from the relevant boundary; or
    ii.  the extent of unprotected area, are within the appropriate limits given in Table 4.Note: In calculating the maximum unprotected area, any areas shown in Diagram 20, and referred to in paragraph 9.9, can be disregarded.
  3. Any parts of the side of the building in excess of the maximum unprotected area should be fire-resisting.

Section 10: Roof coverings

see our page on roof design


10.1   The provisions in this section limit the use, near a boundary, of roof coverings which will not give adequate protection against the spread of fire over them. The term roof covering is used to describe constructions which may consist of one or more layers of material, but does not refer to the roof structure as a whole. The provisions in this Section are principally concerned with the performance of roofs when exposed to fire from the outside.

10.2   The circumstances when a roof is subject to the provisions in Section 9 for space separation are explained in paragraph 9.1.

Other controls on roofs

10.3 There are provisions concerning the fire properties of roofs in other Sections of this document. In the guidance to B1 (paragraph 2.10) there are provisions for roofs that are part of a means of escape. In the guidance to B2 there are provisions for the internal surfaces of rooflights as part of the internal lining of a room or circulation space. In the guidance to B3 there are provisions in Section 4 for roofs which are used as a floor and in Section 6 for roofs that pass over the top of a compartment wall.

Classification of performance

10.4   The performance of roof coverings is designated by reference to the test methods specified in BS 476-3:2004 Fire tests on building materials and structures. Classification and method of test for external fire exposure to roofs or determined in accordance with BS EN 13501-5:2005 Fire classification of construction products and building elements. Classification using data from external fire exposure to roof tests, as described in Appendix A. The notional performance of some common roof coverings is given in Table A5 of Appendix A.
Rooflights are controlled on a similar basis, and plastic rooflights described in paragraphs 10.6 and 10.7 may also be used.

Separation distances

10.5   The separation distance is the minimum distance from the roof (or part of the roof) to the relevant boundary, which may be a notional boundary.

Table 5 sets out separation distances according to the type of roof covering and the size and use of the building. There are no restrictions on the use of roof coverings designated AA, AB or AC (National class) or B ROOF(t4) (European class) classification. In addition, roof covering products (and/or materials) as defined in Commission Decision 2000/553/EC of 6 September 2000 implementing Council Directive 89/106/EEC as regards the external fire performance of roof coverings can be considered to fulfill all of the requirements for performance characteristic ‘external fire performance’ without the need for testing provided that any national provisions on the design and execution of works are fulfilled.

Note: The boundary formed by the wall separating a pair of semi-detached houses may be disregarded for the purposes of this Section (but see Section 5, Diagram 11(b), which deals with roofs passing over the top of a compartment wall).

Plastic rooflights

10.6   Table 6 sets out the limitations on the use of plastic rooflights which have at least a Class 3 (National class) or Class D-s3, d2 (European class) lower surface, and Table 7 sets out the limitations on the use of thermoplastic materials with a TP(a) rigid or TP(b) classification (see also Diagram 23). The method of classifying thermoplastic materials is given in Appendix A.

10.7   When used in rooflights, a rigid thermoplastic sheet product made from polycarbonate or from unplasticised PVC, which achieves a Class 1 (National class) rating for surface spread of flame when tested to BS 476-7:1997 (or 1987 or 1971), or Class C-s3,d2  (European class) can be regarded as having an AA (National class) designation or BROOF(t4) (European class) classification, other than for the purposes of Diagram 11.

Unwired glass in rooflights

10.8   When used in rooflights, unwired glass at least 4mm thick can be regarded as having an AA designation (National class) or BROOF(t4)(European class) classification.

Thatch and wood shingles

10.9   Thatch and wood shingles should be regarded as having an AD/BD/CD designation or EROOF(t4) (European class) classification in Table 5 if performance under BS 476-3:2004 (or 1958) or BS EN 1187:xxxx cannot be established.

Note:  Consideration can be given to thatched roofs being closer to the boundary than shown in Table 5 if, for example, the following precautions (based on Thatched buildings. New properties and extensions [the ‘Dorset Model’]) are incorporated in the design:
  1. the rafters are overdrawn with construction having not less than 30 minutes fire resistance;
  2. the guidance given in Approved Document J Combustion appliances and fuel storage is followed; and
  3. the smoke alarm installation (see Section 1) extends to the roof space.

Section 11: Vehicle access


11.1   For the purposes of this Approved Document, vehicle access to the exterior of a building is needed to enable high reach appliances, such as turntable ladders and hydraulic platforms, to be used and to enable pumping appliances to supply water and equipment for firefighting, search and rescue activities.

Vehicle access routes and hard-standings should meet the criteria described in paragraph 11.4 where they are to be used by fire and rescue service vehicles.

Note:  Requirements cannot be made under the Building Regulations for work to be done outside the site of the works shown on the deposited plans, building notice or initial notice. In this connection it may not always be reasonable to upgrade an existing route across a site to a small building such as a single dwellinghouse. The options in such a case, from doing no work to upgrading certain features of the route, e.g. a sharp bend, should be considered by the Building Control Body in consultation with the fire and rescue service.

11.2   There should be vehicle access for a pump appliance to within 45m of all points within the dwellinghouse.

11.3   Every elevation to which vehicle access is provided in accordance with paragraph 11.2 should have a suitable door(s), not less than 750mm wide, giving access to the interior of the building.

Design of access routes and hard-standings

11.4   A vehicle access route may be a road or other route which, including any inspection covers and the like, meets the standards in Table 8 and paragraph 11.5.

11.5   Turning facilities should be provided in any dead end access route that is more than 20m long (see Diagram 24). This can be by a hammerhead or turning circle, designed on the basis of Table 8.

Appendix A: Performance of materials, products and structures


1.   Much of the guidance in this document is given in terms of performance in relation to British or European Standards for products or methods of test or design or in terms of European Technical Approvals. In such cases the material, product or structure should:
  1. be in accordance with a specification or design which has been shown by test to be capable of meeting that performance; or
    Note:For this purpose, laboratories accredited by the United Kingdom Accreditation Service (UKAS) for conducting the relevant tests would be expected to have the necessary expertise.
  2. have been assessed from test evidence against appropriate standards, or by using relevant design guides, as meeting that performance; or
    Note: For this purpose, laboratories accredited by UKAS for conducting the relevant tests and suitably qualified fire safety engineers might be expected to have the necessary expertise. For materials/products where European standards or approvals are not yet available and for a transition period after they become available, British standards may continue to be used. Any body notified to the UK Government by the Government of another Member State of the European Union as capable of assessing such materials/products against the relevant British Standards, may also be expected to have the necessary expertise. Where European materials/products standards or approvals are available, any body notified to the European Commission as competent to assess such materials or products against the relevant European standards or technical approval can be considered to have the appropriate expertise.
  3. where tables of notional performance are included in this document, conform with an appropriate specification given in these tables; or
  4. in the case of fire-resisting elements:
    i. conform with an appropriate specification given in Part II of the Building Research Establishments’ Report Guidelines for the construction of fire-resisting structural elements (BR 128, BRE 1988); or
    ii. be designed in accordance with a relevant British Standard or Eurocode.

    Note 1:  
    Different forms of construction can present different problems and opportunities for the provision of structural fire protection. Further information on some specific forms of construction can be found in:
    • Timber–BRE 454 Multi-storey timber frame buildings – a design guide 2003 ISBN: 1 86081 605 3
    • Steel–SCI P197 Designing for structural fire safety: A handbook for architects and engineers 1999 ISBN: 1 85942 074 5Note 2: Any test evidence used to substantiate the fire resistance rating of a construction should be carefully checked to ensure that it demonstrates compliance that is adequate and applicable to the intended use. Small differences in detail (such as fixing method, joints, dimensions and the introduction of insulation materials etc.) may significantly affect the rating.
2.  Building Regulations deal with fire safety in buildings as a whole. Thus they are aimed at limiting fire hazard.
The aim of standard fire tests is to measure or assess the response of a material, product, structure or system to one or more aspects of fire behaviour. Standard fire tests cannot normally measure fire hazard. They form only one of a number of factors that need to be taken into account. Other factors are set out in this publication.

Fire resistance

3.  Factors having a bearing on fire resistance, that are considered in this document, are:
  1. fire severity;
  2. building height; and
  3. building occupancy.
4.  The standards of fire resistance given are based on assumptions about the severity of fires and the consequences should an element fail. Fire severity is estimated in very broad terms from the use of the building (its purpose group), on the assumption that the building contents (which constitute the fire load) are similar for buildings in the same use. A number of factors affect the standard of fire resistance specified. These are:
  1. the amount of combustible material per unit of floor area in various types of building (the fire load density);
  2. the height of the top floor above ground, which affects the ease of escape and of firefighting operations, and the consequences should large scale collapse occur;
  3. occupancy type, which reflects the ease with which the building can be evacuated quickly;
  4. whether there are basements, because the lack of an external wall through which to vent heat and smoke may increase heat build-up and thus affect the duration of a fire, as well as complicating firefighting; and
  5. whether the building is of single storey construction (where escape is direct and structural failure is unlikely to precede evacuation).
5.   Performance in terms of the fire resistance to be met by elements of structure, doors and other forms of construction is determined by reference to either:
  1. (National tests) BS 476 Fire tests on building materials and structures, Parts 20-24:1987, i.e. Part 20 Method for determination of the fire resistance of elements of construction (general principles), Part 21 Methods for determination of the fire resistance of loadbearing elements of construction, Part 22 Methods for determination of the fire resistance of non-loadbearing elements of construction, Part 23 Methods for determination of the contribution of components to the fire resistance of a structure, and Part 24 Method for determination of the fire resistance of ventilation ducts (or to BS 476-8:1972 in respect of items tested or assessed prior to 1 January 1988); or
  2. (European tests) Commission Decision 2000/367/EC of 3 May 2000 implementing Council Directive 89/106/EEC as regards the classification of the resistance to fire performance of construction products, construction works and parts thereof.
Note:  The latest version of any standard may be used provided that it continues to address the relevant requirements of the regulations.

All products are classified in accordance with BS EN 13501-2:2007 Fire classification of construction products and building elements. Classification using data from fire resistance tests, excluding ventilation services (excluding products for use in ventilation systems).

BS EN 13501-3:2005 Fire classification of construction products and building elements. Classification using data from fire resistance tests on products and elements used in building service installations: fire resisting ducts and fire dampers (other than smoke control systems).

BS EN 13501-4:2007, Fire classification of construction products and building elements, Part 4 – Classification using data from fire resistance tests on smoke control systems.

The relevant European test methods under BS EN 1364, 1365, 1366 and 1634 are listed in Appendix F.

Table A1 gives the specific requirements for each element in terms of one or more of the following performance criteria:
  1. resistance to collapse (loadbearing capacity), which applies to loadbearing elements only, denoted R in the European classification of the resistance to fire performance;
  2. resistance to fire penetration (integrity), denoted E in the European classification of the resistance to fire performance; and
  3. resistance to the transfer of excessive heat (insulation), denoted I in the European classification of the resistance to fire performance.

Table A2 sets out the minimum periods of fire resistance for elements of structure.

Table A3 sets out criteria appropriate to the suspended ceilings that can be accepted as contributing to the fire resistance of a floor.

Table A4 sets out limitations on the use of uninsulated fire-resisting glazed elements.

These limitations do not apply to the use of insulated fire-resisting glazed elements.


Information on tested elements is frequently given in literature available from manufacturers and trade associations.

Information on tests on fire-resisting elements is also given in such publications as:

Association for Specialist Fire Protection Yellow Book – Fire protection for structural steel in buildings, 4th edition. See Appendix F.


6.   Performance in terms of the resistance of roofs to external fire exposure is determined by reference to either:
  1. (National tests) BS 476-3:2004 External fire exposure roof tests; or
  2. (European tests) Commission Decision 2005/823/EC amending Decision 2001/671/ EC Establishing a classification system for the external fire performance of roofs and roof coverings.

Constructions are classified within the National system by two letters in the range A-D, with an AA designation being the best. The first letter indicates the time to penetration; the second letter a measure of the spread of flame.

Constructions are classified within the European system as BROOF(t4), CROOF(t4), DROOF(t4), EROOF(t4) or FROOF(t4) (with B

ROOF(t4) being the highest performance and FROOF(t4) being the lowest) in accordance with BS EN 13501-5:2005 Fire classification of construction products and building elements – Classification using data from external fire exposure to roof tests.

BS EN 13501-5 refers to four separate tests. The suffix (t4) used above indicates that Test 4 is to be used for the purposes of this Approved Document.

Some roof covering products (and/or materials) can be considered to fulfil all of the requirements for the performance characteristic “external fire performance” without the need for testing, subject to any national provisions on the design and execution of works being fulfilled. These roof covering products are listed in Commission Decision 2000/553/EC of 6th September 2000 implementing Council Directive 89/106/EEC as regards the external fire performance of roof coverings.

In some circumstances roofs, or parts of roofs, may need to be fire-resisting, for example if used as an escape route or if the roof performs the function of a floor. Such circumstances are covered in Sections 2, 4 and 6.

Table A5 gives notional designations of some generic roof coverings.

Reaction to fire

7.   Performance in terms of reaction to fire to be met by construction products is determined by Commission Decision 200/147/EC of 8 February 2000 implementing Council Directive 89/106/EEC as regards the classification of the reaction to fire performance of construction products.

Note: The designation of xxxx is used for the year reference for standards that are not yet published. The latest version of any standard may be used provided that it continues to address the relevant requirements of the Regulations.

All products, excluding floorings, are classified as †A1, A2, B, C, D, E or F (with class A1 being the highest performance and F being the lowest) in accordance with BS EN 13501-1:2002 Fire classification of construction products and building elements, Part 1 – Classification using data from reaction to fire tests.

†  The classes of reaction to fire performance of A2, B, C, D and E are accompanied by additional classifications related to the production of smoke (s1, s2, s3) and/or flaming droplets/particles (d0, d1, d2).

The relevant European test methods are specified as follows:

  • BS EN ISO 1182:2002 Reaction to fire tests for building products – Non-combustibility test
  • BS EN ISO 1716:2002 Reaction to fire tests for building products – Determination of the gross calorific value
  • BS EN 13823:2002 Reaction to fire tests for building products – Building products excluding floorings exposed to the thermal attack by a single burning item
  • BS EN ISO 11925-2:2002 Reaction to fire tests for building products,Part 2 – Ignitability when subjected to direct impingement of a flame.
  • BS EN 13238:2001 Reaction to fire tests for building products – conditioning procedures and general rules for selection of substrates.

Non-combustible materials

8.  Non-combustible materials are defined in Table A6 either as listed products, or in terms of performance:
  1. (National classes) when tested to BS 476-4:1970 Fire tests on building materials and structures – Non-combustibility test for materials or BS 476-11:1982 Fire tests on building materials and structures – Method for assessing the heat emission from building materials.
  2. (European classes) when classified as class A1 in accordance with BS EN 13501-1:2002 Fire classification of construction products and building elements. Classification using data from reaction to fire tests when tested to BS EN ISO 1182:2002 Reaction to fire tests for building products – Non-combustibility test and BS EN ISO 1716:2002 Reaction to fire tests for building products – Determination of the gross calorific value.
Table A6 identifies non-combustible products and materials, and lists circumstances where their use is necessary.

Materials of limited combustibility

9. Materials of limited combustibility are defined in Table A7:

  1. (National classes) by reference to the method specified in BS 476-11:1982;
  2. (European classes) in terms of performance when classified as class A2-s3, d2 in accordance with BS EN 13501-1:2002 Fire classification of construction products and building elements. Classification using data from reaction to fire tests when tested to BS EN ISO 1182:2002 Reaction to fire tests for building products – Non-combustibility test or BS EN ISO 1716:2002 Reaction to fire tests for building products – Determination of the gross calorific value and BS EN 13823:2002 Reaction to fire tests for building products – Building products excluding floorings exposed to the thermal attack by a single burning item.

Table A7 also includes composite products (such as plasterboard) which are considered acceptable, and where these are exposed as linings they should also meet any appropriate flame spread rating.

Internal linings

see our section on internal linings

10.   Flame spread over wall or ceiling surfaces is controlled by providing for the lining materials or products to meet given performance levels in tests appropriate to the materials or products involved.

11.   Under the National classifications, lining systems which can be effectively tested for ‘surface spread of flame’ are rated for performance by reference to the method specified in BS 476-7:1997 (or 1987 or 1971) Fire tests on building materials and structures. Method of test to determine the classification of the surface spread of flame of products under which materials or products are classified 1, 2, 3 or 4 with Class 1 being the highest.

Under the European classifications, lining systems are classified in accordance with BS EN 13501-1:2002 Fire classification of construction products and building elements, Part 1 – Classification using data from reaction to fire tests. Materials or products are classified as A1, A2, B, C, D, E or F, with A1 being the highest. When a classification includes ‘s3, d2’, it means that there is no limit set for smoke production and/or flaming droplets/particles.

12.  To restrict the use of materials which ignite easily, which have a high rate of heat release and/or which reduce the time to flashover, maximum acceptable ‘fire propagation’ indices are specified, where the National test methods are being followed. These are determined by reference to the method specified in BS 476-6:1989 or 1981. Index of performance (I) relates to the overall test performance, whereas sub-index (i1) is derived from the first three minutes of test.

13.  The highest National product performance classification for lining materials is Class 0. This is achieved if a material or the surface of a composite product is either:

  1. composed throughout of materials of limited combustibility; or
  2. a Class 1 material which has a fire propagation index (I) of not more than 12 and sub-index (i1) of not more than 6.

Note: Class 0 is not a classification identified in any British Standard test.

14.  Composite products defined as materials of limited combustibility (see paragraph 9 and Table A7) should in addition comply with the test requirement appropriate to any surface rating specified in the guidance on requirements B2, B3 and B4.

15.  The notional performance ratings of certain widely used generic materials or products are listed in Table A8 in terms of their performance in the traditional lining tests BS 476-6:1989 and BS 476-7:1997 or in accordance with BS EN 13501-1:2002.

16.  Results of tests on proprietary materials are frequently given in literature available from manufacturers and trade associations.

Any reference used to substantiate the surface spread of flame rating of a material or product should be carefully checked to ensure that it is suitable, adequate and applicable to the construction to be used. Small differences in detail, such as thickness, substrate, colour, form, fixings, adhesive etc, may significantly affect the rating.

Thermoplastic Materials

17.   A thermoplastic material means any synthetic polymeric material which has a softening point below 200ºC if tested to BS EN ISO 306:2004 method A120 Plastics – Thermoplastic materials – Determination of Vicat softening temperature. Specimens for this test may be fabricated from the original polymer where the thickness of material of the end product is less than 2.5mm.

18.  A thermoplastic material in isolation can not be assumed to protect a substrate when used as a lining to a wall or ceiling. The surface rating of both products must therefore meet the required classification. If, however, the thermoplastic material is fully bonded to a non-thermoplastic substrate, then only the surface rating of the composite will need to comply.

19.   Concessions are made for thermoplastic materials used for window glazing, rooflights, and lighting diffusers within suspended ceilings, which may not comply with the criteria specified in paragraphs 11 to 16. They are described in the guidance on requirements B2 and B4.

20.  For the purposes of the requirements B2 and B4 thermoplastic materials should either be used according to their classification 0-3, under the BS 476-6:1989 and BS 476-7:1997 tests as described in paragraphs 11 to 16, (if they have such a rating), or they may be classified TP(a) rigid, TP(a) flexible, or TP(b) according to the following methods:

TP(a) rigid:
  1. Rigid solid pvc sheet;
  2. Solid (as distinct from double- or multiple-skin) polycarbonate sheet at least 3mm thick;
  3. Multi-skinned rigid sheet made from unplasticised pvc or polycarbonate which has a Class 1 rating when tested to BS 476-7:1997 or 1971 or 1987; and
  4. Any other rigid thermoplastic product, a specimen of which (at the thickness of the product as put on the market), when tested to BS 2782:1970 as amended in 1974: Method 508A Rate of burning (Laboratory method), performs so that the test flame extinguishes before the first mark and the duration of flaming or afterglow does not exceed five seconds following removal of the burner.

TP(a) flexible:

Flexible products not more than 1mm thick which comply with the Type C requirements of BS 5867-2:1980 Specification for fabrics for curtains and drapes – Flammability requirements when tested to BS 5438:1989 Methods of test for flammability of textile fabrics when subjected to a small igniting flame applied to the face or bottom edge of vertically oriented specimens, Test 2, with the flame applied to the surface of the specimens for 5, 15, 20 and 30 seconds respectively, but excluding the cleansing procedure; and


  1. Rigid solid polycarbonate sheet products less than 3mm thick, or multiple-skin polycarbonate sheet products which do not qualify as TP(a) by test; or
  2. Other products which, when a specimen of the material between 1.5 and 3mm thick is tested in accordance with BS 2782:1970, as amended in 1974: Method 508A, has a rate of burning which does not exceed 50mm/minute.

Note: If it is not possible to cut or machine a 3mm-thick specimen from the product then a 3mm test specimen can be moulded from the same material as that used for the manufacture of the product.

Note: Currently, no new guidance is possible on the assessment or classification of thermoplastic materials under the European system since there is no generally accepted European test procedure and supporting comparative data.

Fire test methods

21.  A guide to the various test methods in BS 476 and BS 2782 is given in PD 6520 Guide to fire test methods for building materials and elements of construction (available from the British Standards Institution).

A guide to the development and presentation of fire tests and their use in hazard assessment is given in BS 6336:1998 Guide to development and presentation of fire tests and their use in hazard assessment.

1.Part 21 for loadbearing elements, Part 22 for non-loadbearing elements, Part 23 for fire-protecting suspended ceilings, and Part 24 for ventilation ducts. BS 476-8 results are acceptable for items tested or assessed before 1 January 1988.
2.Applies to loadbearing elements only (see B3.ii and Appendix E).
3.Guidance on increasing the fire resistance of existing timber floors is given in BRE Digest 208 Increasing the fire resistance of existing timber floors (BRE 1988).
4.A suspended ceiling should only be relied on to contribute to the fire resistance of the floor if the ceiling meets the appropriate provisions given in Table A3.
5.The guidance in Section 9 allows such walls to contain areas which need not be fire-resisting (unprotected areas).
6.Unless needed as part of a wall in item 5a or 5b.
7.Except for any limitations on glazed elements given in Table A4.
8.See Table A4 for permitted extent of uninsulated glazed elements.
9.The National classifications do not automatically equate with the equivalent classifications in the European column, therefore products cannot typically assume a European class unless they have been tested accordingly.

‘R’ is the European classification of the resistance to fire performance in respect of loadbearing capacity; ‘E’ is the European classification of the resistance to fire performance in respect of integrity; and ‘I’ is the European classification of the resistance to fire performance in respect of insulation.

Application of the fire resistance standards in table A2:

a.  Where one element of structure supports or carries or gives stability to another, the fire resistance of the supporting element should be no less than the minimum period of fire resistance for the other element (whether that other element is loadbearing or not).

There are circumstances where it may be reasonable to vary this principle, for example:
  1. where the supporting structure is in the open air, and is not likely to be affected by the fire in the building; or
  2. where the supporting structure is in a different compartment, with a fire-separating element (which has the higher standard of fire resistance) between the supporting and the separated structure; or
  3. where a plant room on the roof needs a higher fire resistance than the elements of structure supporting it.

b.  Where an element of structure forms part of more than one building or compartment, that element should be constructed to the standard of the greater of the relevant provisions.

c.  Although most elements of structure in a single storey building may not need fire resistance (see the guidance on requirement B3, paragraph 4.4(a)), fire resistance will be needed if the element:
  1. is part of (or supports) an external wall and there is provision in the guidance on requirement B4 to limit the extent of openings and other unprotected areas in the wall; or
  2. is part of (or supports) a compartment wall, including a wall common to two or more buildings, or a wall between a dwellinghouse and an attached or integral garage; or
  3. supports a gallery.

For the purposes of this paragraph, the ground storey of a building which has one or more basement storeys and no upper storeys, may be considered as a single-storey building. The fire resistance of the basement storeys should be that appropriate to basements.

Appendix B: Fire doors

1.   All fire doors should have the appropriate performance given in Table B1 either:
  1. by their performance under test to BS 476-22 Fire tests on building materials and structures. Methods for determination of the fire resistance of non-loadbearing elements of construction, in terms of integrity for a period of minutes,e.g. FD30. A suffix (S) is added for doors where restricted smoke leakage at ambient temperatures is needed; or
  2. as determined with reference to Commission Decision 2000/367/EC of 3 May 2000 implementing Council Directive  89/106/EEC as regards the classification of the resistance to fire performance of construction products, construction works and parts thereof. All fire doors should be classified in accordance with BS EN 13501-2:2003 Fire classification of construction products and building elements. Classification using data from fire resistance tests (excluding products for use in ventilation systems). They are tested to the relevant European method from the following:BS EN 1634-1:2008 Fire resistance and smoke control tests for door and shutter assemblies, openable windows and elements of building hardware. Fire resistance tests for doors, shutters and openable windows;BS EN 1634-2:2008 Fire resistance and smoke control tests for door and shutter assemblies, openable windows and elements of building hardware. Fire resistance characterisation test for elements of building hardware;BS EN 1634-3:2004 Fire resistance and smoke control tests for door and shutter assemblies, openable windows and  elements of building hardware. Smoke control test for door and shutter assemblies.

The performance requirement is in terms of integrity (E) for a period of minutes. An additional classification of Sa is used for all doors where restricted smoke leakage at ambient temperatures is needed.

The requirement (in either case) is for test exposure from each side of the door separately. Any test evidence used to substantiate the fire resistance rating of a door or shutter should be carefully checked to ensure that it adequately demonstrates compliance and is applicable to the adequately complete installed assembly. Small differences in detail (such as glazing apertures, intumescent strips, door frames and ironmongery etc.) may significantly affect the rating.

Note 1: The latest version of any standard may be used provided that it continues to address the relevant requirements of the Regulations.

Note 2: Until such time that the relevant harmonised product standards are published, for the purposes of meeting the Building Regulations, products tested in accordance with BS EN 1634-1 (with or without pre-fire test mechanical conditioning) will be deemed to have satisfied the provisions provided that they achieve the minimum fire resistance in terms of integrity,

as detailed in Table B1.

2.    Fire doors serving an attached or integral garage should be fitted with a self-closing device.

3.    Unless shown to be satisfactory when tested as part of a fire door assembly, the essential components of any hinge on which a fire door is hung should be made entirely from materials having a melting point of at least 800ºC.

4.   Tables A1 and A2 set out the minimum periods of fire resistance for the elements of structure to which performance of some doors is linked. Table A4 sets out limitations on the use of uninsulated glazing in fire doors.

5.   BS 8214:1990 gives recommendations for the specification, design, construction, installation and maintenance of fire doors constructed with non-metallic door leaves.

Guidance on timber fire-resisting doorsets, in relation to the new European test standard, may be found in Timber fire-resisting doorsets: maintaining performance under the new European test standard published by TRADA (Timber Research and Development Association).

Guidance for metal doors is given in Code of practice for fire-resisting metal doorsets published by the DSMA (Door and Shutter Manufacturers’ Association) in 1999.

6.  Hardware used on fire doors can significantly affect performance in fire. Notwithstanding the guidance in this Approved Document guidance is available in Hardware for fire and escape doors published by the Builders’ Hardware Industry Federation.

Appendix C: Methods of measurement

1.  Some form of measurement is an integral part of many of the provisions in this document. Diagram C1 shows how the height of the top storey should be measured.

Appendix D: Purpose groups

1.   Many of the provisions in this document are related to the use of the building. The use classifications are termed purpose groups and represent different levels of hazard. They can apply to a whole building, or (where a building is compartmented) to a compartment in the building, and the relevant purpose group should be taken from the main use of the building or compartment.

2.  Table D1 sets out the purpose group classification.
Note: This is only of relevance to this Approved Document.

Appendix E: Definitions

Note: Except for the items marked * (which are from the Building Regulations), these definitions apply only to Part B.

Access room A room through which the only escape route from an inner room passes.

Accommodation stair A stair, additional to that or those required for escape purposes, provided for the convenience of occupants.

Alternative escape routes Escape routes sufficiently separated by either direction and space, or by fire-resisting construction, to ensure that one is still available should the other be affected by fire.

Note: A second stair, balcony or flat roof which enables a person to reach a place free from danger from fire, is considered an alternative escape route for the purposes of a dwellinghouse.

Alternative exit  One of two or more exits, each of which is separate from the other.

Appliance ventilation duct A duct provided to convey combustion air to a gas appliance.

Automatic release mechanism  A device which will allow a door held open by it to close automatically in the event of each or any one of the following:
  1. detection of smoke by automatic apparatus suitable in nature, quality and location;
  2. operation of a hand-operated switch fitted in a suitable position;
  3. failure of electricity supply to the device, apparatus or switch;
  4. operation of the fire alarm system if any.

Basement storey  A storey with a floor which at some point is more than 1200mm below the highest level of ground adjacent to the outside walls.

Boundary  The boundary of the land belonging to the building, or where the land abuts a road, railway, canal or river, the centre line of that road,railway, canal or river (See Diagram 17.)

*Building Any permanent or temporary building but not any other kind of structure or erection. A reference to a building includes a reference to part of a building.

Building Control Body  A term used to include both Local Authority Building Control and Approved Inspectors.

Cavity barrier  A construction, other than a smoke curtain, provided to close a concealed space against penetration of smoke or flame, or provided to restrict the movement of smoke or flame within such a space.

Ceiling  A part of a building which encloses and is exposed overhead in a room, protected shaft or circulation space. (The soffit of a rooflight is included as part of the surface of the ceiling, but not the frame. An upstand below a rooflight would be considered as a wall.)

Circulation space  A space (including a protected stairway) mainly used as a means of access between a room and an exit from the building or compartment.

Class 0  A product performance classification for wall and ceiling linings. The relevant test criteria are set out in Appendix A, paragraph 13.

Compartment (fire)  A building or part of a building, comprising one or more rooms, spaces or storeys, constructed to prevent the spread of fire to or from another part of the same building, or an adjoining building. (A roof space above the top storey of a compartment is included in that compartment.) (See also ‘Separated part’.)

Compartment wall or floor  A fire-resisting wall/floor used in the separation of one fire compartment from another. (Constructional provisions are given in Section 5.)

Concealed space or cavity  A space enclosed by elements of a building (including a suspended ceiling) or contained within an element, but not a room, cupboard, circulation space, protected shaft or space within a flue, chute, duct, pipe or conduit.

Dead end  Area from which escape is possible in one direction only.

Direct distance  The shortest distance from any point within the floor area, measured within the external enclosures of the building, to the nearest storey exit ignoring walls, partitions and fittings, other than the enclosing walls/partitions to protected stairways.
Dwellinghouse  A unit of residential accommodation occupied (whether or not as a sole or main residence):
  1. by a single person or by people living together as a family
  2. by not more than six residents living together as a single household, including a household where care is provided for residents.(See also paragraphs 0.22 and 0.23.)
* Dwellinghouse does not include a flat or a building containing a flat.
Element of structure:
  1. a member forming part of the structural frame of a building or any other beam or column;
  2. a loadbearing wall or loadbearing part of a wall;
  3. a floor;
  4. a gallery (but not a loading gallery, fly gallery, stage grid, lighting bridge, or any gallery provided for similar purposes or for maintenance and repair);
  5. an external wall;
  6. a compartment wall (including a wall common to two or more buildings). (However, see the guidance to B3, paragraph 4.4, for exclusions from the provisions for elements of structure.)
Escape lighting  That part of the emergency lighting which is provided to ensure that the escape route is illuminated at all material times.
Escape route  Route forming that part of the means of escape from any point in a building to a final exit.
European Technical Approval  A favourable technical assessment of the fitness for use of a construction product for an intended use, issued for the purposes of the Construction Products Directive by a body authorised by a Member State to issue European Technical Approvals for those purposes and notified by that Member State to the European Commission.
European Technical Approvals issuing body   A body notified under Article 10 of the Construction Products Directive. The details of these institutions are published in the ‘C’ series of the Official Journal of the European Communities.
Evacuation lift  A lift that may be used for the evacuation of people in a fire.
Exit passageway  A protected passageway connecting a protected stairway to a final exit (exit passageways should be protected to the same standard as the stairway that they serve).
External wall (or side of a building)  Includes a part of a roof pitched at an angle of more than 70º to the horizontal, if that part of the roof adjoins a space within the building to which persons have access (but not access only for repair or maintenance).
Final exit  The termination of an escape route from a building giving direct access to a street, passageway, walkway or open space, and sited to ensure the rapid dispersal of persons from the vicinity of a building so that they are no longer in danger from fire and/or smoke.
Note:Windows are not acceptable as final exits.
Fire door  A door or shutter, provided for the passage of persons, air or objects, which together with its frame and furniture as installed in a building, is intended (when closed) to resist the passage of fire and/or gaseous products of combustion, and is capable of meeting specified performance criteria to those ends. (It may have one or more leaves, and the term includes a cover or other form of protection to an opening in a fire-resisting wall or floor, or in a structure surrounding a protected shaft.)
Fire-resisting (fire resistance)  The ability of a component or construction of a building to satisfy, for a stated period of time, some or all of the appropriate criteria specified in the relevant part of BS 476.
Fire-separating element  A compartment wall, compartment floor, cavity barrier and construction enclosing a protected escape route and/or a place of special fire hazard.
Fire stop  A seal provided to close an imperfection of fit or design tolerance between elements or components, to restrict the passage of fire and smoke.
* Flat  A separate and self-contained premises constructed or adapted for use for residential purposes and forming part of a building from some other part of which it is divided horizontally.
Gallery  A raised area or platform around the sides or at the back of a room which provides extra space.
Habitable room  A room used, or intended to be used, for dwellinghouse purposes (including; for the purposes of Part B, a kitchen, but not a bathroom).
Height (of a building or storey for the purposes of Part B)  Height of the top storey above ground is measured as shown in Appendix C, Diagram C1.
Inner room  Room from which escape is possible only by passing through another room (the access room).
Material of limited combustibility   A material performance specification that includes non-combustible materials, and for which the relevant test criteria are set out in Appendix A, paragraph 9.
Means of escape  Structural means whereby [in the event of fire] a safe route or routes is or are provided for persons to travel from any point in a building to a place of safety.
Non-combustible material   The highest level of reaction to fire performance. The relevant test criteria are set out in Appendix A, paragraph 8.
Notional boundary   A boundary presumed to exist between buildings on the same site (see Section 9, Diagram 18).
Occupancy type  A purpose group identified in Appendix D.
Pipe (for the purposes of Section 7)   Includes pipe fittings and accessories; and excludes a flue pipe and a pipe used for ventilating purposes (other than a ventilating pipe for an above around drainage system).
Places of special fire hazard   Oil-filled transformer and switch gear rooms, boiler rooms, storage space for fuel or other highly flammable substances, and rooms housing a fixed internal combustion engine.
Protected circuit   An electrical circuit protected against fire.
Protected stairway   A stair discharging through a final exit to a place of safety (including any exit passageway between the foot of the stair and the final exit) that is adequately enclosed with fire-resisting construction.
Purpose group   A classification of a building according to the purpose to which it is intended to be put. See Appendix D, Table D1.
Relevant boundary   The boundary which the side of the building faces, (and/or coincides with) and which is parallel, or at an angle of not more than 80º, to the side of the building (see Section 9 Diagram 17). A notional boundary can be a relevant boundary.
Rooflight   A dome light, lantern light, skylight, ridge light, glazed barrel vault or other element intended to admit daylight through a roof.
Room (for the purposes of B2)   An enclosed space within a building that is not used solely as a circulation space. (The term includes not only conventional rooms, but also walk-in cupboards that are not fittings, and large spaces such as warehouses and auditoria. The term does not include voids such as ducts, ceiling voids and roof spaces.)
Sheltered housing   Includes:
  1. two or more dwellings in the same building;
  2. two or more dwellings on adjacent sites where those dwellings are, in each case, designed and constructed for the purpose of providing residential accommodation for vulnerable or elderly people who receive, or who are to receive, a support service.
Single-storey building   A building consisting of a ground storey only. (A separated part which consists of a ground storey only, with a roof to which access is only provided for repair or maintenance, may be treated as a single storey building.) Basements are not included in counting the number of storeys in a building.
Site (of a building)  The land occupied by the building, up to the boundaries with land in other ownership.
Smoke alarm   A device containing within one housing all the components, except possibly the energy source, necessary for detecting smoke and giving an audible alarm.
Self-closing device   A device which is capable of closing the door from any angle and against any latch fitted to the door.
Storey   includes:
  1. any gallery if its area is more than half that of the space into which it projects; and
  2. a roof, unless it is accessible only for maintenance and repair.
Storey exit  A final exit, or a doorway giving direct access into a protected stairway, firefighting lobby or external escape route.
Suspended ceiling (fire-protecting)   A ceiling suspended below a floor, which contributes to the fire resistance of the floor. Appendix A, Table A3, classifies different types of suspended ceiling.
Technical specification   A standard or a European Technical Approval Guide. It is the document against which compliance can be shown in the case of a standard and against which an assessment is made to deliver the European Technical Approval.
Thermoplastic material   See Appendix A, paragraph 17.
Unprotected area   In relation to a side or external wall of a building means:
  1. window, door or other opening; and Note: Windows that are not openable and are designed and glazed to provide the necessary level of fire resistance need not be regarded as an unprotected area.
  2. any part of the external wall which has less than the relevant fire resistance set out in Section 8.
  3. any part of the external wall which has combustible material more than 1mm thick attached or applied to its external face, whether for cladding or any other purpose. Combustible material in this context is any material which does not have a Class 0 rating.)