BR App Doc B Vol 1

7/26/2019 BR App Doc B Vol 1

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Fire safety

The Building Regulations 2000

B1 Means of warning and escapeB2 Internal fire spread (linings)

B3 Internal fire spread (structure)

B4 External fire spread

B5 Access and facilities for the fire

VOLUME 1 DWELLINGHOUSES

APPROVED DOCUMENT

Coming into effect April 2007


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VOLUME 1

MAIN CHANGES IN THE

2006 EDITIONThis edition of Approved Document B, Fire safety,replaces the 2000 edition. The main changes are:

General

a. Approved Document B: The ApprovedDocument has been split into two volumes.Volume 1 deals with dwellinghouses, Volume 2deals with buildings other than dwellinghouses.

Wherever possible the guidance in Volume 1has been tailored and simplified to be moredirectly relevant to dwellinghouses.

Introduction

b. Certification Schemes: Suitable schemesmay be accepted by Building Control Bodiesas evidence of compliance.

c. Residential Sprinklers: The use of sprinklersystems in accordance with BS 9251:2005is recognised.

d. Adult Placements: Reference is made tothe code of practice for fire safety in adultplacements.

B1

e. Fire Alarms: The guidance on smoke alarmshas been amended such that alarms should beinstalled in accordance with BS 5839- 6:2004.

Simple guidance has been retained, in theform of a commentary on this standard, sothat most users of the Approved Documentwill not necessarily need to obtain a copy ofthe standard.

All smoke alarms should have a standbypower supply.

Where a dwellinghouse is extendedsmoke alarms should be provided in thecirculation spaces.

f. Means of escape: The guidance on meansof escape has been restructured to make it

vi. Guidance on the appreplacement window

vii. Guidance on the usesystems in houses wstairways is given.

B3

g. Integral Garages: The pfloor has been included the 100mm step betweeand integral garages.

h. Compartmentation: Gu

junction between comparoofs has been clarified

i. Cavity Barriers: Windoware only suitable for usethey are constructed of appropriate thickness.

B4

j. Roof Coverings: The gucoverings incorporates tsystem of classification 13501-5:2005.

B5

k. Vehicle Access: There sa pump appliance to witwithin a dwellinghouse.

Appendix Bl. Self-Closing Devices: O

between a dwellinghousgarage, fire doors need self closing devices.


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Use of guidance 4

The Approved Documents 4

Limitation on requirements 4

Materials and workmanship 4

Interaction with other legislation 5

General introduction: Fire safety 8

Scope 8

Arrangement of sections 8

Building maintenance and the provisionof information 8

Property protection 9

Independent schemes of certificationand accreditation 9

Residential sprinklers 9

Inclusive design 10

Material alteration 10

Alternative approaches 10

B1 Means of warning and escape The Requirement 12

B1 Guidance 13

Performance 13

Introduction 13

Analysis of the problem 13

Security 14

General 14

B1 Section 1: Fire detection andfire alarm systems 15

Introduction 15

General 15

Large houses 15

Provisions for escapmore than 4.5m abo

General provisions

Work on existing hou

B2 Internal fire spre The Requirement

B2 GuidancePerformance

Introduction

B2 Section 3: Wall a

Classification of linin

Variations and speci

Thermoplastic mater

B3 Internal fire spre The Requirement

B3 Guidance

Performance

Introduction

B3 Section 4: Loadof structure

Introduction

Fire resistance stand

B3 Section 5: Comp

Introduction

Provision of comparConstruction of comcompartment floors

Openings in compar

B3 Section 6: Conc

Contents

PAGE


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B4 External fire spread The Requirement 41

B4 Guidance 42

Performance 42

Introduction 42

B4 Section 8: Construction ofexternal walls 43

Introduction 43

Fire resistance standard 43

External surfaces 43

B4 Section 9: Space separation 44

Introduction 44

Boundaries 44

Unprotected areas 45

Methods for calculating acceptableunprotected area 46

B4 Section 10: Roof coverings 49

Introduction 49

Classification of performance 49

Separation distances 49

B5 Access and facilities forthe Fire and Rescue Service The Requirement 52

B5 Guidance 53

Performance 53

Introduction 53

B5 Section 11: Vehicle access 54

Introduction 54

Design of access routes and hard-standings 54

Appendices

Appendix A: Performance of materials,

Appendix B: Fire doors

Appendix C: Methods of m

Appendix D: Purpose grou

Appendix E: Definitions

Appendix F: Standards anpublications referred to

Diagrams

B1

1. Means of escape fro

2. Alternative arrangem

3. Fire separation in houthan one floor over 4ground level

4. Ground or basementan enclosed space

5. Gallery floors with no

6. Alternative cavity barin roof space over prin a house with a flooabove ground level

7. Fire resistance of are

external stairs

B2

8. Lighting diffuser in re

9. Layout restrictions onrooflights, TP(b) roofllighting diffusers

B3

10. Separation between dwellinghouse

11. Junction of compartmwith roof

12. Interrupting conceale( iti )

PAGE

B CONTENTS


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20. Unprotected areas which may bedisregarded in assessing the separation

distance from the boundary 4721. The effect of a canopy on

separation distance 47

22. Permitted unprotected areas forMethod 1 48

23. Limitations on spacing and size ofplastic rooflights having a Class 3(National Class) or Class D-s3,

d2 (European class) or TP(b)lower surface 49

B5

24. Turning facilities 54

Appendix C

C1. Height of top storey in building 68

Tables

B2

1. Classification of linings 26

2. Limitations applied to thermoplasticrooflights and lighting diffusers insuspended ceilings and Class 3plastic rooflights 28

B3

3. Maximum nominal internal diameter ofpipes passing through a fire separatingelement 38

B4

4. Permitted unprotected areas forMethod 2 48

5. Limitations on roof coverings 50

6. Class 3 (National class) or ClassD-s3, d2 (European class) plasticrooflights: limitations on use andboundary distance 51

7 TP( ) d TP(b) l ti fli ht

A4. Limitations onuninsulated g

on escape rouA5. Notional desig

A6. Use and definnon-combust

A7. Use and definlimited combu

A8. Typical perforof some gene

and products

B1. Provisions for

D1. Classification

PAGE

CONTENTS


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THE APPROVED DOCUMENTS

This document is one of a series that has beenapproved and issued by the Secretary of Statefor the purpose of providing practical guidancewith respect to the requirements of Schedule 1to and Regulation 7 of the Building Regulations2000 (SI 2000/2531) for England and Wales.

At the back of this document is a list ofall the documents that have been approvedand issued by the Secretary of State for

this purpose.

The Approved Documents are intended toprovide guidance for some of the more commonbuilding situations. However, there may well bealternative ways of achieving compliance withthe requirements.

Thus there is no obligation to adopt anyparticular solution contained in an Approved

Document if you prefer to meet the relevantrequirement in some other way.

Other requirements

The guidance contained in an ApprovedDocument relates only to the particularrequirements of the Regulations which thatdocument addresses. The building work will alsohave to comply with the Requirements of anyother relevant paragraphs in Schedule 1 to theRegulations.

There are Approved Documents which giveguidance on each of the other requirements inSchedule 1 and on Regulation 7.

LIMITATION ON REQUIREMENTS

In accordance with Regulation 8, therequirements in Parts A to D, F to K, N and P(except for paragraphs H2 and J6) of Schedule 1to the Building Regulations do not requireanything to be done except for the purpose ofsecuring reasonable standards of health andsafety for persons in or about buildings (andany others who may be affected by buildings ormatters connected with buildings) This is one

MATERIALS AND W

Any building work which is srequirements imposed by SBuilding Regulations shouldRegulation 7, be carried outand in a workmanlike manne

You may show that you havRegulation 7 in a number ofthe appropriate use of a promarking in accordance with

Products Directive (89/106/Voltage Directive (73/23/EEC93/68/EEC)2and the EMC DEEC)3, as amended by the C(93/68/EEC)4, or a product cappropriate technical specifiin those Directives), a Britishalternative national technicaMember State of the Europe

or of another State signatoryon the European Economic provides an equivalent levelprotection, or a product covor European certificate issueTechnical Approval Issuing bconditions of use are in accterms of the certificate.

You will find further guidanc

Document supporting Reguand workmanship.

Independent certification

There are many UK productschemes. Such schemes cethe requirements of a recogwhich is appropriate to the pmaterial is to be used. Matecertified may still conform to

Many certification bodies wschemes are accredited by Accreditation Service (UKAS

Use of guidanceB


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Since the fire performance of a product,component or structure is dependent uponsatisfactory site installation and maintenance,independent schemes of certification and

accreditation of installers and maintenancefirms of such will provide confidence inthe appropriate standard of workmanshipbeing provided.

Building Control Bodies may accept thecertification of products, components, materialsor structures under such schemes as evidence ofcompliance with the relevant standard. Similarly,Building Control Bodies may accept the certification

of the installation or maintenance of products,components, materials or structures under suchschemes as evidence of compliance with therelevant standard. Nonetheless, a BuildingControl Body will wish to establish, in advanceof the work, that any such scheme is adequatefor the purposes of the Building Regulations.

Technical specifications

Building Regulations are made for specificpurposes, such as health and safety, energyconservation and the welfare and convenienceof people. Standards and technical approvals arerelevant guidance to the extent that they relateto these considerations. However, they may alsoaddress other aspects of performance such asserviceability, or aspects which, although theyrelate to health and safety, are not covered bythe Regulations.

When an Approved Document makes referenceto a named standard, the relevant version ofthe standard is the one listed at the end of thepublication. However, if this version of thestandard has been revised or updated by theissuing standards body, the new version maybe used as a source of guidance provided itcontinues to address the relevant requirementsof the Regulations.

The appropriate use of a product which complieswith a European Technical Approval as defined inthe Construction Products Directive will meet therelevant requirements.

The Department intends to issue periodicamendments to its Approved Documents

INTERACTION

LEGISLATION

Houses in multiple

This guidance may adesign and construcconsidered to be ho(HMOs), as defined iproviding there are nin any self-containedof HMOs is typically Authority who may rover and above this guidance on the assfire and preventive mcontained in the HouRating System OperFebruary 2006 (ISBN

The Workplace (HeRegulations 1992

The Workplace (Heal

Regulations 1992 cowhich affect buildingrequirements are nowRegulations but for fWorkplace health, saWorkplace (Health, Sa1992, Approved CodThe Health and Safepublished by HMSO

The Workplace (HealRegulations 1992 apof flats and similar bcleaners, wardens anto work in these comrequirements of the covered by this Part the provisions may ssituations described

the Workplace ReguThe Construction (DRegulations 2006

The purpose of this Aprovide guidance onfor the completed buth i k f fi d i

USE OF GUIDANCE


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The Construction Products Directive

The Construction Products Directive (CPD) is oneof the New Approach Directives, which seek toremove technical barriers to trade within the

European Economic Area (EEA) as part of themove to complete the Single Market. The EEAcomprises the European Community and thosestates in the European Free Trade Association(other than Switzerland).

The intention of the CPD is to replace existingnational standards and technical approvalswith a single set of European-wide technicalspecifications for construction products (i.e.

harmonised European standards or EuropeanTechnical Approvals). Any manufacturer whoseproducts have CE marking showing that theyare specified according to European technicalspecifications cannot have these productsrefused entry to EEA markets on technicalgrounds. In the UK, the CPD was implementedby the Construction Products Regulations, whichcame into force on 27 December 1991 and were

amended on 1 January 1995 by the ConstructionProducts (Amendment) Regulations 1994.

This document refers to, and utilises within itsguidance, a large number of British Standards,in relation to Codes of Practice and fire testmethods (typically the BS 476 series ofdocuments). In order to facilitate harmonisationand the use of the new technical specificationsand their supporting European test standards,

guidance is also given on the classification ofproducts in accordance with those standards.

Guidance is given for the appropriate use and/orspecification of a product to which one or moreof the following apply:

1. a product bearing CE marking in accordancewith the Construction Products Directive(89/106/EEC) as amended by the CE markingDirective (93/68/EEC);

2. a product tested and classified in accordancewith the European Standards (BS EN)referred to in the Commission Decision2000/147/EC1and/or Commission Decision2000/367/EC2;

3. a product complying with an appropriate

relation to the European fire tclearly defined.

As new information becomefurther harmonised Europea

to this document are publiswill be made available.

Designation of standards

The designation of xxxx is referred to for standards thapublished. The latest versionbe used provided that it conrelevant requirements of the

Commission guidance pap

The following guidance papDecisions are directly relevaunder the Construction Prod

Guidance paper G

The European classification sto fire performance of const

Guidance paper J

Transitional arrangements uProducts Directive.

Commission Decision of 8 F(2000/147/EC) implementing89/106/EEC as regards the reaction to fire performance of

Commission Decision of 3 MEC) implementing Council Das regards the classificationto fire performance of constconstruction works and part

Commission Decision of 26(2000/605/EC) amending Deestablishing the list of produClasses A No contribution t

for in Decision 94/611/EC imArticle 20 of Council Directivon construction products.

Corrigenda Corrigendum tDecision 2000/147/EC of 8 implementing Council Direcregards the classification of

B USE OF GUIDANCE


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Environmental Protection

Requirements under Part B of the BuildingRegulations and the guidance in this ApprovedDocument are made for the purpose of ensuring

the health and safety of people in and aroundbuildings.

The Environment Agency publishes guidance onthe design and construction of buildings for thepurpose of protecting the environment. Thisincludes Pollution Prevention Guidelines (PPG18)on Managing Fire Water and Major Spillages,which seeks to minimise the effects of waterrun-off from firefighting. It is aimed at medium

to large (and small, high-risk) commercial andindustrial sites and sets out requirements forthe construction of containment areas forcontaminated water and such other measures.

It should be noted that compliance with theBuilding Regulations does not depend uponcompliance with other such guidance.

USE OF GUIDANCE


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Scope

0.1 Approved Document B (Fire safety) hasbeen published in two volumes. Volume 1 dealssolely with dwellinghouses (see Appendix E andBuilding Regulation 2(1)), while Volume 2 dealswith all other types of building covered by theBuilding Regulations.

Where very large (over 18m in height) or unusualdwellinghouses are proposed some of theguidance in Volume 2 may be needed to

supplement that given by Volume 1.

Arrangement of sections

0.2 The functional requirements B1 to B5 ofSchedule 1 of the Building Regulations are dealtwith separately in one or more Sections. Therequirement is reproduced at the start of therelevant Sections, followed by an introduction

to the subject.0.3 The provisions set out in this documentdeal with different aspects of fire safety, with thefollowing aims:

B1: To ensure satisfactory provision ofmeans of giving an alarm of fire and asatisfactory standard of means of escapefor persons in the event of fire in a building.

B2: To ensure fire spread over theinternal linings of buildings is inhibited.

B3: To ensure the stability of buildingsin the event of fire; to ensure that there is asufficient degree of fire separation withinbuildings and between adjoining buildings;to provide automatic fire suppressionwhere necessary; and to inhibit the unseenspread of fire and smoke in concealedspaces in buildings.

B4: To ensure external walls and roofshave adequate resistance to the spread offire over the external envelope, and thatspread of fire from one building to anotheris restricted.

B5: To ensure satisfactory access

where variations in the standbeing considered. A higher

of the requirements may be of one or more of the other guidance in the document aconsidered as a package aiacceptable standard of fire s

Appendices: provisions coone of Part Bs requiremen

0.5 Guidance on matters

than one of the Sections is iAppendices, covering the fo

Appendix A fire perforproducts

Appendix B provisions

Appendix C methods

Appendix D a classificgroups

Appendix E definitions

Appendix F Standardspublicatio

Fire performance of materand structures

0.6 Much of the guidancedocument is given in terms

relation to standard fire testdrawn together in Appendixis made where appropriate. protection systems, referenstandards for system designStandards referred to are lis

Fire doors

0.7 Guidance in respect

in Appendix B.

Methods of measurement

0.8 Some form of measupart of much of the guidancand methods are set out in A

General introduction: Fire safetyB


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measures incorporated into the design of adwellinghouse are adequately maintained.Building Regulations do not impose anyrequirements on the management of a building.

However, the eventual owners and occupiersshould be provided with sufficient informationto operate, maintain and use the building inreasonable safety.

For individual dwellinghouses, basic advice on theproper use and maintenance of systems providedin the building, such as emergency egress windows,fire doors, smoke alarms, sprinklers etc., can helpto ensure that these systems are maintained and

kept available for use. Householders should alsobe made aware that unauthorised materialalterations (see paragraph 0.20) may leave themliable to prosecution.

In providing fire protection of any kind indwellinghouses, it should be recognised thatmeasures which significantly interfere with theday-to-day convenience of the occupants maybe less reliable in the long term.

Property protection

0.12 There are often many stakeholders,including insurers, who have a valid interestin the fire protection measures which areincorporated into a buildings design. To ensurethat the most effective fire protection measuresare applied which are appropriate to the specificproperty, early consultation with the main

stakeholders is essential. Failure to consult withstakeholders at an early stage could result inadditional measures being required aftercompletion, the use of the building beingrestricted, or insurance premiums and/ordeductibles being increased.

Building Regulations are intended to ensure thata reasonable standard of life safety is providedin case of fire. The protection of property,

including the building itself, often requiresadditional measures and insurers will, in general,seek their own higher standards before acceptingthe insurance risk.

Guidance for asset protection in the Civil andDefence Estates is given in the Crown FireSt d d bli h d b th P t Ad i

upon satisfactory sitmaintenance, indepecertification and accand maintenance firm

confidence in the apworkmanship being

Confidence that the can be achieved willuse of a system, matwhich is provided unproduct conformity caccreditation of insta

Third party accredite

certification schemeof identifying materiaproducts or structurethat they have the rebut additionally provsystems, materials, pactually supplied arespecification or desi

Third party accredita

materials, products omeans of ensuring thconducted by knowlappropriate standardreliability of the antic

Many certification boschemes are accred

0.15 Building Cont

certification of produor structures under scompliance with the Building Control Bodcertification of the inproducts, componenunder such schemeswith the relevant staBuilding Control Bodadvance of the work

adequate for the purRegulations.

Residential sp

0.16 Sprinkler systdwellinghouses can

GENERAL INTRODUCTION: FIRE SAFETY


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throughout the building. However, where thesprinklers are being installed as a compensatoryfeature to address a specific risk or hazard it maybe acceptable to protect only part of a building.

Further guidance can also be found in Sprinklersfor Safety: Use and Benefits of IncorporatingSprinklers in Buildings and Structures, BAFSA(2006) ISBN: 0 95526 280 1.

0.18 There are many alternative or innovativefire suppression systems available. Where theseare used it is necessary to ensure that suchsystems have been designed and tested foruse in domestic buildings and are fit for their

intended purpose.

Inclusive design

0.19 The fire safety aspects of the BuildingRegulations are made for securing reasonablestandards of health and safety of persons in andabout buildings. This is intended to include allpeople including people with disabilities. The

provisions set out in this Approved Document areconsidered to be a reasonable standard for mostbuildings. However, there may be some peoplewhose specific needs are not addressed. In somesituations additional measures may be needed toaccommodate these needs. This should be doneon a case by case basis.

Material alteration

0.20 Under Regulation 3, the term materialalteration is defined by reference to a list ofrelevant requirements of Schedule 1 to theBuilding Regulations. That list includes therequirements of Parts B1, B3, B4 and B5. Thismeans that an alteration which, at any stage ofthe work, results in a building being lesssatisfactory than it was before in relation tocompliance with the requirements of Parts B1,

B3, B4 or B5 is a material alteration, and istherefore controlled by Regulation 4 as it is classedas building work. Regulation 4(1) requires thatany building work carried out in relation to amaterial alteration complies with the applicablerequirements of Schedule 1 to the Regulations,while Regulation 4(2) requires that once thatb ildi k h b l t d th b ildi

If other codes or guides arerelevant recommendations csafety in the particular publifollowed, rather than a mixtu

and provisions in the relevanApproved Document. Howecircumstances where it is nepublication to supplement a

Guidance documents intendassessing fire safety in exisoften include provisions whthan those set out in this Apother standards applicable t

such, these documents are appropriate for use where bcontrolled by the Regulation

Registered group homes

0.22 Depending on the naand their management needsto treat an unsupervised groto six residents as an ordinaHowever, because such plaregistered, the registration aconsulted to establish whetadditional fire safety measuwill require.

Where an existing house of to be put to use as an unsupfor not more than 6 mental hit should be regarded as a Pbuilding if the means of escaccordance with HTM 88: Guin NHS housing in the commhandicapped (or mentally ill)building is new, it may be mregard it as being in Purpos

Adult placements

0.23 Where a dwellinghoupurposes of an Adult Placem

fulfils the criteria of the AduSchemes (England) Regulat2070) and where no building guidance in the joint code oby the National Association Services (www.naaps.co.ukto satisfy Part B of the Build

B GENERAL INTRODUCTION: FIRE SAFETY


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buildings. Fire safety engineering may also besuitable for solving a problem with an aspect ofthe building design which otherwise follows theprovisions in this document.

British Standard BS 7974:2001Application offire safety engineering principles to the design ofbuildings and supporting published documents(PDs) provide a framework and guidance on thedesign and assessment of fire safety measuresin buildings. Following the discipline of BS 7974should enable designers and Building ControlBodies to be aware of the relevant issues, theneed to consider the complete fire safety system,

and to follow a disciplined analytical framework.0.26 Factors that should be taken intoaccount include:

a. the anticipated probability of a fire occurring;

b. the anticipated fire severity;

c. the ability of a structure to resist the spreadof fire and smoke; and

d. the consequential danger to people in andaround the building.

0.27 A wide variety of measures could beconsidered and incorporated to a greater or lesserextent, as appropriate in the circumstances.These include:

a. the adequacy of means to prevent fire;

b. early fire warning by an automatic detection

and warning system;c. the standard of means of escape;

d. provision of smoke control;

e. control of the rate of growth of a fire;

f. the adequacy of the structure to resist theeffects of a fire;

g. the degree of fire containment;

h. fire separation between buildings or partsof buildings;

i. the standard of active measures for fireextinguishment or control;

j. facilities to assist the fire and rescue service;

k th il bilit f t i t ff

Buildings of speciainterest

0.29 Some variatioin this document ma

Part B applies to exiin buildings of speciainterest, where adhethis document mightIn such cases it wouaccount a range of fiwhich are dealt with of which are not addset these against an

and risk peculiar to t

GENERAL INTRODUCTION: FIRE SAFETY


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This Approved Document deals with the followingRequirement from Part B of Schedule 1 to the

Building Regulations 2000 (as amended).

Requirement Limits on application

Means of warning and escape

B1. The building shall be designed and constructed so that

there are appropriate provisions for the early warning of

fire, and appropriate means of escape in case of fire from

the building to a place of safety outside the building capable

of being safely and effectively used at all material times.

Requirement B1 does no

provided under Section 3

1952 (power to provide p

The RequirementB1 MEANS OF WARNING AND ESCAPE


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Performance

In the Secretary of States view the RequirementB1 will be met if:

a. there is sufficient means for giving earlywarning of fire for persons in the building;

b. there are routes of sufficient number andcapacity, which are suitably located to enablepersons to escape to a place of safety in theevent of fire; and

c. the routes are sufficiently protected from theeffects of fire, where necessary.

Introduction

B1.i These provisions relate to building workand material changes of use which are subjectto the functional requirement B1; they maytherefore affect new or existing buildings. Theyare concerned with the measures necessary toensure reasonable facilities for means of warningand escape in case of fire. They are only concernedwith fire precautions where these are necessaryto safeguard escape routes.

They assume that in the design of the building,reliance should not be placed on external rescueby the fire and rescue service nor should it bebased on a presumption that they will attendan incident within a given time. This ApprovedDocument has been prepared on the basis that,in an emergency, the occupants of any part of abuilding should be able to escape safely withoutany external assistance.

It should also be noted that the guidance fora typical one or two storey dwellinghouse islimited to the provision of smoke alarms andto the provision of openable windows foremergency egress.

Analysis of the problem

B1.ii The design of means of escape and theprovision of other fire safety measures, such assmoke alarms, should be based on an assessmentof the risk to the occupants in the event of fire

not controlled by theless likely that the fire

of the building itself accidentally in circulprovided that the coareas is restricted.

B1.iv The primary dits early stages is nonoxious gases produmost of the casualtiethe way to escape ro

designed to provide therefore provide aplimit the rapid spread

Criteria for means o

B1.v The basic prinmeans of escape are

a. that there shouldescape from mos

b. where direct escnot possible, it splace of relative stairway, which ia reasonable trav

c. in certain conditiescape (a dead eproviding reason

depend on the uassociated fire riof the building, tand the numberswithin the dead e

The ultimate place oof the effects of the

B1.vi For the purposfollowing are not acc

a. lifts (except for ainstalled evacuat

b. portable ladders

c. manipulative appfold-down ladde

Guidance


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Even with protected horizontal escape routesthe distance to a final exit or protected stairwayneeds to be limited because the structure doesnot give protection indefinitely.

B1.viii Protected stairways are designed toprovide virtually fire sterile areas which lead toplaces of safety outside the building. Once insidea protected stairway, a person can be consideredto be safe from immediate danger from flame andsmoke. They can then proceed to a place of safetyat their own pace. To enable this to be done,flames, smoke and gases must be excludedfrom these escape routes, as far as is reasonablypossible, by fire-resisting construction and doorsor by an appropriate smoke control system, or bya combination of both of these methods.

Security

B1.ix The need for easy and rapid evacuationof a building in case of fire may conflict with thecontrol of entry and exit in the interest of security.Measures intended to prevent unauthorised

access can also hinder entry of the fire andrescue service to rescue people trapped by fire.

Potential conflicts should be identified andresolved at the design stage and not left untilafter completion of the work. The architecturalliaison officers attached to most police forcesare a valuable source of advice.

This document does not intend for the types

of lock used on windows (see paragraph 2.8)and entrance doors to dwellinghouses to becontrolled under the Building Regulations.

General

Use of the document

B1.x Section 1 deals with fire detection andalarm systems. Section 2 deals with means

of escape.

B1 GUIDANCE


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Introduction1.1 Provisions are made in this section forsuitable arrangements to be made in dwellinghousesto give early warning in the event of fire.

General

1.2 The installation of smoke alarms, or

automatic fire detection and alarm systemscan significantly increase the level of safetyby automatically giving an early warning of fire.The following guidance is appropriate for mostdwellinghouses. However, where it is knownthat the occupants of a proposed dwellinghouseare at a special risk from fire, it may be moreappropriate to provide a higher standard ofprotection, e.g. additional detectors.

1.3 All new dwellinghouses should be providedwith a fire detection and fire alarm system inaccordance with the relevant recommendationsof BS 5839-6:2004 to at least a Grade DCategory LD3 standard.

1.4 The smoke and heat alarms should bemains-operated and conform to BS 5446-1:2000or BS 5446-2:2003, respectively: Fire detectionand fire alarm devices for dwellinghouses,

Part 1 Specification for smoke alarms; or Part 2Specification for heat alarms. They should havea standby power supply, such as a battery (eitherrechargeable or non-rechargeable) or capacitor.More information on power supplies is given inclause 15 of BS 5839-6:2004.

Note:BS 5446-1 covers smoke alarms based onionization chamber smoke detectors and optical(photo-electric) smoke detectors. The different

types of detector respond differently tosmouldering and fast-flaming fires. Either typeof detector is generally suitable. However, thechoice of detector type should, if possible,take into account the type of fire that might beexpected and the need to avoid false alarms.Optical detectors tend to be less affected byl l l f i i ibl ti l h f

1.7 A large dwelli(excluding basementwith a Grade A Categin BS 5839-6:2004, waccordance with theBS 5839-1:2002 for

Material altera

1.8 Where new haabove the ground floprovided at ground flexit from the new rooalarm system shouldshould be provided ithe dwellinghouse in1.10 to 1.18 to ensurnew rooms are warnimpede their escape

Sheltered hous

1.9 The detectionhousing scheme withshould have a connepoint (or alarm receivperson in charge is adetected in one of th

can identify the dweThese provisions areto the common partsdevelopment, such asheltered accommodOther residential purDocument B Volume

Positioning of

heat alarms1.10 Detailed guidainstallation of fire detin dwellinghouses is However, the followito most common situ

Section 1: Fire detection and firealarm systems


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1.14 Where more than one alarm is installed theyshould be linked so that the detection of smokeor heat by one unit operates the alarm signal inall of them. The manufacturers instructionsabout the maximum number of units that canbe linked should be observed.

1.15 Smoke alarms/detectors should be sitedso that:

a. there is a smoke alarm in the circulationspace within 7.5m of the door to everyhabitable room;

b. they are ceiling-mounted and at least 300mmfrom walls and light fittings (unless, in thecase of light fittings, there is test evidenceto prove that the proximity of the light fittingwill not adversely affect the efficiency of thedetector). Units designed for wall-mountingmay also be used provided that the units areabove the level of doorways opening into thespace and they are fixed in accordance withmanufacturers instructions; and

c. the sensor in ceiling-mounted devices isbetween 25mm and 600mm below the ceiling(25-150mm in the case of heat detectors orheat alarms).

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

1.16 It should be possible to reach the smokealarms to carry out routine maintenance, such astesting and cleaning, easily and safely. For this

reason smoke alarms should not be fixed overa stair or any other opening between floors.

1.17 Smoke alarms should not be fixed nextto or directly above heaters or air-conditioningoutlets. They should not be fixed in bathrooms,showers, cooking areas or garages, or any otherplace where steam, condensation or fumescould give false alarms.

1.18 Smoke alarms should not be fitted inplaces 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 arenormally much warmer or colder than the rest ofthe space, because the temperature differencemight create air currents which move smoke

f th it

1.20 The electrical installawith Approved Document P

1.21 Any cable suitable fobe used for the power suppl

to smoke alarm systems. It particular fire survival propehouses (BS 5839-6:2004 spcables for Grade A and B sysused for interconnecting alashould be readily distinguishsupplying mains power, e.g

Note:Mains-powered smokinterconnected using radio-

this does not reduce the lifeany standby power supply bthis case, the smoke alarmsto separate power circuits (s

1.22 Other effective optiondescribed in BS 5839-1:2002For example, the mains supto extra low voltage in a cona standby trickle-charged b

distributed at that voltage to

Design and installat

1.23 It is essential that firealarm systems are properly and maintained. Where a firinstalled, an installation andcertificate should be providecertification schemes for fireand related services are an providing the fullest possiblea level of quality, reliability a

1.24 A requirement for mabe made as a condition of pBuilding Control Body. Howof developers and builders iimportance of providing theinformation on the use of thon its maintenance (or guidamaintenance contractors). S

Note:BS 5839-1 and BS 58that occupiers should receivinstructions concerning the maintenance of the alarm sy

B1 FIRE ALARM AND FIRE DETECTION SYSTEMS


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Introduction

2.1 The means of escape from a typical oneor two storey dwellinghouse is relatively simpleto provide. Few provisions are specified in thisdocument beyond ensuring that means areprovided for giving early warning in the event offire (see Section 1) and that suitable means areprovided for emergency egress from each storeyvia windows or doors.

With increasing height more complex provisions

are needed because emergency egress throughupper windows becomes increasingly hazardous.It is then necessary to protect the internal stairway.If there are floors more than 7.5m above groundlevel, the risk that the stairway will becomeimpassable before occupants of the upper partsof the dwellinghouse have escaped is appreciable,and an alternative route from those parts shouldbe provided. See Diagram 1.

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

2.2 In providing any kind of fire protection inhouses it should be recognised that measureswhich significantly interfere with the day-to-dayconvenience of the occupants may be lessreliable in the long term.

Provisions for escape from the

ground storey

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

a. open directly onto a hall leading to theentrance or other suitable exit; or

b. be provided with a window (or door) whichcomplies with paragraph 2.8.

Note: See also General Provisions.

Provisions for escape from upper

floors not more than 4.5m above

ground level

Provisions for

floors more thaground level

2.5 The provisionneed not be followedmore than one interneffective alternative physically separated

Note:The necessary

matter of judgement, efire-resisting construc

Dwellinghouses witabove ground level

2.6 The dwellinghprotected stairway athe top floor can be alternative escape ro

a. The upper storeysshould be served(protected at all

i. extend to a fi

ii. give access tat ground levexits and sepfire-resisting

see Diagram b. The top storey sh

lower storeys by fibe provided withleading to its ow

Note: See also Gene

Dwellinghouses wit4.5m above ground

2.7 Where a dwelstoreys with floors mlevel (typically a dwestoreys) then, in addiin paragraph 2.6:

a. an alternative es

Section 2: Means of escape

B1


20/86

B1 MEANS OF ESCAPE

4.5m

4.5m

b. Dwellinghouse with upper flo

below 4.5m (see paragraph 2

a. Single storey dwellinghouse

(see paragraph 2.3)

Escape via protected

stair. No inner rooms

allowed.


stair. No inner rooms

allowed.


stair. Provide alternative

escape or sprinklers.

No inner rooms allowed.


stair. Inner rooms

provided with egress

windows.


stair. Inner rooms


windows.

Escape via entrance

hall. Inner rooms


windows or doors.

Escape via entrance

hall. Inner rooms


windows or doors.

Escape via stair and

egress windows.

Alternatively provide a

protected stair.

Escape via entrance hall.

Inner rooms provided withegress windows or doors.

Escape via entrance hall.

Inner rooms provided withegress windows or doors.

d Dwellinghouse with more thac Dwellinghouse with one floor

Diagram 1 Means of escape from dwellinghouses

MEANS OF ESCAPE


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General provisions

Emergency egress windows and external doors

2.8 Any window provided for emergencyegress purposes and any external door providedfor escape should comply with the followingconditions:

a. the window should have an unobstructedopenable area that is at least 0.33m2andat least 450mm high and 450mm wide (theroute through the window may be at an angle

Note 1:Approved Dfalling, collision and guarding height of 8of a window in a rooopening may be 600

Note 2: Locks (with and stays may be fitsubject to the stay bcatch, which may be

Note 3: Windows shthat they will remain

Diagram 2 Alternative arrangementsfor final exits

See para 2.6(a)

Diagram 3 Fire swith

over 4

MEANS OF ESCAPE

B1 MEANS OF ESCAPE


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Inner rooms2.9 A room whose only escape route is throughanother room is termed an inner room and isat risk if a fire starts in that other room (accessroom). This situation may arise with open-planlayouts and galleries. Such an arrangement isonly acceptable where the inner room is:

a. a kitchen;

b. a laundry or utility room;c. a dressing room;

d. a bathroom, WC, or shower room;

e. any other room on a floor, not more than4.5m above ground level, provided with anemergency egress window which complieswith paragraph 2.8; or

f. 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 itcomplies with the above, not more than one doorseparates the room from an interlinked smokealarm and none of the access rooms is a kitchen.

Balconies and flat roofs2.10 A flat roof forming paescape should comply with th

a. the roof should be part from which escape is be

b. the route across the roostorey exit or external es

c. the part of the roof formand its supporting strucany opening within 3m oshould provide 30 minut(see Appendix A, Table A

2.11 Where a balcony or flfor escape purposes guardiin which case it should meeApproved Document K Protcollision and impact.

B1 MEANS OF ESCAPE

Mid point of roof slopeFor an escape route to be

acceptable into an enclosed

courtyard or garden, the depth

of back garden should exceed:

a. the height of the house

above ground level (X); or

b. where a rear extension is

provided, the height of the

extensions (Y)

whichever is greater.

E

w

p

o

YY

X

X

Diagram 4 Ground or basement storey exit into an enclosed space

See para 2.8(b)

MEANS OF ESCAPE


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Galleries

2.12 A gallery should be provided with analternative exit or, where the gallery floor isnot more than 4.5m above ground level, an

emergency egress window which complies withparagraph 2.8. Alternatively, where the gallery flooris not provided with an alternative exit or escapewindow, it should comply with the following;

a. the gallery should overlook at least 50% ofthe room below (see Diagram 5);

b. the distance between the foot of the accessstair to the gallery and the door to the roomcontaining the gallery should not exceed 3m;

c. the distance from the head of the accessstair to any point on the gallery should notexceed 7.5m; and

d. any cooking facilities within a roomcontaining a gallery should either:

i. be enclosed with fire-resistingconstruction; or

ii. be remote from the stair to the galleryand positioned such that they do notprejudice the escape from the gallery.

Basements

2.13 Because of thmay be blocked by sbasement or ground

contains any habitabshould be provided w

a. an external door egress from the b2.8); or

b. a protected stairbasement to a fin

Cavity barriers

2.14 Cavity barriersthe enclosures to a pdwellinghouse with aabove ground level (

MEANS OF ESCAPE

Visible area to

be at least 50%

of floor area in

lower room

7.5m

max

3mmax

1 This diagram does not apply where the gallery is

i. provided with an alternative escape route; or

ii. provided with an emergency egress window

Diagram 5 Gallery floors with noalternative exit

See para 2.12

Roof spac

a. With cavity ba

Diagram 6 Alterarran

over in a hmoregroun

See para 2.14

B1 MEANS OF ESCAPE


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External escape stairs

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

a. All doors giving access to the stair shouldbe fire-resisting, except that a fire-resistingdoor is not required at the head of any stairleading downwards where there is only oneexit from the building onto the top landing.

b. Any part of the external envelope of thebuilding within 1800mm of (and 9m verticallybelow) the flights and landings of an externalescape stair should be of fire-resistingconstruction, except that the 1800mm dimensionmay be reduced to 1100mm above the toplevel of the stair if it is not a stair up from abasement to ground level (see Diagram 7).

c. There is protection by fire-resistingconstruction for any part of the building(including any doors) within 1800mm of theescape route from the stair to a place ofsafety, unless there is a choice of routes fromthe foot of the stair that would enable thepeople escaping to avoid exposure to theeffects of the fire in the adjoining building.

d. Any stair more than 6m in vertical extent isprotected from the effects of adverse weatherconditions. (This should not be taken to implya full enclosure. Much will depend on thelocation of the stair and the degree of protectiongiven to the stair by the building itself).

e. Glazing in areas of fire-resisting constructionmentioned above should also be fire-resisting(integrity but not insulation) and fixed shut.

Air circulation systems in more than 4.5m above gro

2.16 Air circulation systemwithin an individual dwelling

more than 4.5m above grouthe guidance given in paragventilation ducts pass throuwalls into another building tgiven in Approved Documenbe followed.

2.17 With these types of sprecautions are needed to athe system allowing smoke

a protected stairway:a. Transfer grilles should n

wall, door, floor or ceilinprotected stairway.

b. Any duct passing througa protected stairway or be of rigid steel construbetween the ductwork ashould be fire-stopped.

c. Ventilation ducts supplydirectly to or from a proshould not serve other a

d. Any system of mechanicrecirculates air and whicstairway and other areasto shut down on the detwithin the system.

e. A room thermostat for aheating system should bliving room, at a height band 1830mm, and its mshould not exceed 27C

Passenger lifts

2.18 Where a passenger lidwellinghouse and it serves

4.5m above ground level, it located in the enclosure to t(see paragraph 2.6) or be coresisting lift shaft.

Work on existing ho

B1 MEANS OF ESCAPE

No fire resistance

required for door

1100mm

zone

above1800mm zone

Diagram 7 Fire resistance of areasadjacent to external stairs

See para 2.15

MEANS OF ESCAPE


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Schedule 1. In addition, the building should nothave a lesser level of compliance, after the workhas been completed, with other applicable Partsof Schedule 1.

For the purposes of Part B1, where a window islocated such that, in a new dwellinghouse, anescape window would be necessary and thewindow is of sufficient size that it could be usedfor the purposes of escape then:

a. the replacement window opening should besized to provide at least the same potentialfor escape as the window it replaces; or

b. where the original window is larger thannecessary for the purposes of escape, thewindow opening could be reduced down tothe minimum specified in paragraph 2.8.

Note: Part B3 makes provisions for cavitybarriers around window openings in some formsof construction. Where windows are replaced itmay be necessary to consider if adequateprotection is maintained.

Material alterations

2.20 Paragraph 0.20 sets out the requirementsrelating to material alterations. What constitutesreasonable provision where undertaking materialalterations would depend on the circumstances inthe particular case and would need to take accountof historic value (see paragraph 0.29). Possibleways of satisfying the requirements include:

a. Smoke alarmsWhere new habitable rooms are provided thensmoke alarms should be provided in accordancewith paragraph 1.8.

b. Loft conversions

Where a new storey is to be added by convertingan existing roof space, the provisions for escapeneed to be considered throughout the full

extent of the escape route. For example, a loftconversion to a two-storey house will result inthe need to protect the stairway (by providingfire-resisting doors and partitions) wherepreviously no protection may have existed(see paragraph 2.6a).

Note: If it is considered undesirable to replace

Alternatively, it may sprinkler protection tconjunction with a fidoor (E20), in order tfrom the upper storearranged to allow thto access an escape(in accordance with of a fire in the open-should be separatedwith fire-resisting co

MEANS OF ESCAPE

B2 INTERNAL FIRE SPREAD (LININGS)


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This Approved Document deals with thefollowing Requirement from Part B of Schedule 1

to the Building Regulations 2000 (as amended).

Requirement Limits on application

Internal fire spread (linings)

B2.(1) To inhibit the spread of fire within the building, the

internal linings shall:

(a) adequately resist the spread of flame over their

surfaces; and

(b) have, if ignited, a rate of heat release or a rate of

fire growth, which is reasonable in the circumstances.

(2) In this paragraph internal linings mean the materials

or products used in lining any partition, wall, ceiling or

other internal structure.

The RequirementB2 INTERNAL FIRE SPREAD (LININGS)


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Performance

In the Secretary of States view the Requirementsof B2 will be met if the spread of flame over theinternal linings of the building is restricted bymaking provision for them to have low rates ofsurface spread of flame and, in some cases, tohave a low rate of heat release, so as to limit thecontribution that the fabric of the building makesto fire growth. In relation to the European firetests and classification system, the requirementsof B2 will be met if the heat released from the

internal linings is restricted by making provisionfor them to have a resistance to ignition and arate of fire growth which are reasonable in thecircumstances.

The extent to which this is necessary isdependent on the location of the lining.

Introduction

Fire spread and internal linings

B2.i The choice of materials for walls andceilings can significantly affect the spread of afire and its rate of growth, even though they arenot likely to be the materials first ignited.

It is particularly important in circulation spaceswhere linings may offer the main means by whichfire spreads and where rapid spread is most likely

to prevent occupants from escaping.Several properties of lining materials influencefire spread. These include the ease of ignitionand the rate at which the lining material gives offheat when burning. The guidance relating to theEuropean fire tests and classification provides forcontrol of internal fire spread through control ofthese properties. This document does not givedetailed guidance on other properties, such as

the generation of smoke and fumes.

Floors and stairs

B2.ii The provisions do not apply to the uppersurfaces of floors and stairs because they arenot significantly involved in a fire until it is welldeveloped and thus do not play an important

Classification of pe

B2.v Appendix A dof performance and test (see paragraphs

The national classifictests in BS 476 Fire and structures, nameof test for fire propagBS 476-7:1997 Meththe classification of tof products. Howevecombustibility test fo11:1982 Method for from building producmethod of meeting Cavailable for classificmaterials if they do nrating under BS 476referred to as TP(a) rTP(b), are used.

The European classiBS EN 13501-1:2002construction producPart 1 Classification fire tests. They are bfour European test m

BS EN ISO 1182for building produ

BS EN ISO 1716for building prodgross calorific va

BS EN 13823:20for building prodexcluding flooringattack by a single

BS EN ISO 1192tests for buildingwhen subjected to

For some building prgenerally accepted gprocedure for testingaccordance with thetests. Until such a tim

Guidance

B2


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Classification of linings

3.1 Subject to the variations and specificprovisions described in paragraphs 3.2 to 3.16,the surface linings of walls and ceilings shouldmeet the following classifications:

Table 1 Classification of linings

Location Nationalclass (1)

Europeanclass (1)(3)(4)

Small rooms (2)of areanot more than 4m2

3 D-s3, d2

Domestic garages of areanot more than 40m2

Other rooms (2)(including garages)

1 C-s3, d2

Circulation spaceswithin dwellinghouses

Notes:

1. See paragraph B2.v.

2. For meaning of room, see definition in Appendix E.

3. The National classifications do not automatically equate withthe equivalent classifications in the European column, thereforeproducts cannot typically assume a European class, unless theyhave been tested accordingly.

4. When a classification includes s3, d2, this means that there is nolimit set for smoke production and/or flaming droplets/particles.

Definition of walls

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

a. the surface of glazing (except glazing indoors); and

b. any part of a ceiling which slopes at an angleof more than 70 to the horizontal.

But a wall does not include:

c. doors and door frames;

d. window frames and frames in which glazingis fitted;

But a ceiling does not includ

e. trap doors and their fram

f. the frames of windows oAppendix E) and framesfitted; or

g. architraves, cover mouldexposed beams and sim

Variations and spec

Walls

3.4 Parts of walls in roomperformance than specifiednot poorer than Class 3 (NaD-s3, d2 (European class) pof those parts in any one roone half of the floor area of maximum of 20m2.

Fire-protecting suspended3.5 A suspended ceiling overall fire resistance of a floSuch a ceiling should satisfyshould also meet the provisTable A3.

Fire-resisting ceilings

3.6 Cavity barriers are ne

concealed floor or roof spachowever, this need can be rof a fire-resisting ceiling belo

Rooflights

3.7 Rooflights should meclassification in 3.1. Howevewith at least a Class 3 rating3.1 calls for a higher standa

limitations in Table 2 and in Note: No guidance is currenperformance requirements itests as there is no generallclassification procedure.

Section 3: Wall and ceiling linings

WALL AND CEILING LININGS


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Note: No guidance is currently possible on theperformance requirements in the European firetests as there is no generally accepted test andclassification procedure.

Windows and internal glazing3.9 External windows to rooms (thoughnot to circulation spaces) may be glazed withthermoplastic materials, if the material can beclassified as a TP(a) rigid product.

Internal glazing should meet the provisions inparagraph 3.1.

Notes:

1. A wall does not include glazing in a door(see paragraph 3.2).

2. Attention is drawn to the guidance onthe safety of glazing in Approved Document NGlazing safety in relation to impact, openingand cleaning.

Rooflights

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

a. the lower surface has a TP(a) (rigid) or TP(b)classification

b. the size and disposition of the rooflightsaccords with the limits in Table 2 and withthe guidance to B4 in Table 7.

Lighting diffusers

3.11 The following provisions apply to lightingdiffusers which form part of a ceiling. They arenot concerned with diffusers of light fittingswhich are attached to the soffit of, or suspendedbeneath 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 orused below rooflights or other sources of light.

3.12 Thermoplastic lighting diffusers should notbe used in fire-protecting or fire-resisting ceilings,unless they have been satisfactorily tested aspart of the ceiling system that is to be used to

id th i t fi t ti

3.13 Subject to the rooms and circulatiostairways) may incordiffusers if the follow

a. Wall and ceiling sspace above thethan the upper spanels) should coprovisions of partype of space be

b. If the diffusers arthere are no rest

c. If the diffusers ar

should be limitedTable 2 and Diag

Suspended or stret

3.14 The ceiling of either as a suspendedfrom panels of a therTP(a) flexible classifipart of a fire-resisting

not exceed 5m2in aron all its sides.

Diagram 8 Lightto ce

See para 3.11

B2 WALL AND CEILING LININGS


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Table 2 Limitations applied to thermoplastic rooflights and lightingin suspended ceilings and Class 3 plastic rooflights

Minimumclassification of

lower surface

Use of space belowthe diffusers or

rooflight

Maximum area ofeach diffuser panel or

rooflight (1)

(m)

Max total area ofdiffuser panels

and rooflights aspercentage of floorarea of the space inwhich the ceiling is

located (%)

TP(a) Any exceptprotected stairway

No limit (2) No limit

Class 3 (3)or TP(b) Rooms 5 50 (4)

Circulation spacesexcept protectedstairways

5 15

(4)

Notes:

1. Smaller panels can be grouped together provided that the overall size of the group and the space between one groudimensions shown in Diagram 9.

2. Lighting diffusers of TP(a) flexible rating should be restricted to panels of not more than 5m2each, see paragraph 3.14

3. There are no limits on Class 3 material in small rooms see Table 1.

4. The minimum 3m separation specified in Diagram 9 between each 5m must be maintained. Therefore, in some caseuse the maximum percentage quoted.

Diagram 9 Layout restrictions on Class 3 plastic rooflights, TP(b) roTP(b) lighting diffusers

See Table 2

INTERNAL FIRE SPREAD (STRUCTURE)


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This Approved Document deals with the followingRequirement from Part B of Schedule 1 to the

Building Regulations 2000 (as amended).

Requirement Limits on applicat

Internal fire spread (structure)

B3. (1) The building shall be designed and constructed so

that, in the event of fire, its stability will be maintained fora reasonable period.

(2) A wall common to two or more buildings shall be

designed and constructed so that it adequately resists the

spread of fire between those buildings. For the purposes of

this sub-paragraph a house in a terrace and a semi-detached

house are each to be treated as a separate building.

(3) Where reasonably necessary to inhibit the spread

of fire within the building, measures shall be taken, to an

extent appropriate to the size and intended use of the

building, comprising either or both of the following:

(a) sub-division of the building with fire-resisting

construction;

(b) installation of suitable automatic fire suppression

systems.

(4) The building shall be designed and constructed sothat the unseen spread of fire and smoke within concealed

spaces in its structure and fabric is inhibited.

Requirement B3(

alterations to any p

33 of the Prison A

The Requirement

B3


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Performance

In the Secretary of States view the Requirementsof B3 will be met:

a. if the loadbearing elements of structure ofthe building are capable of withstanding theeffects of fire for an appropriate periodwithout loss of stability;

b. if the building is sub-divided by elements offire-resisting construction into compartments;

c. if any openings in fire-separating elements(see Appendix E) are suitably protected inorder to maintain the integrity of the element(i.e. the continuity of the fire separation); and

d. if any hidden voids in the construction aresealed and sub-divided to inhibit the unseenspread of fire and products of combustion, inorder to reduce the risk of structural failureand the spread of fire, in so far as they posea threat to the safety of people in and aroundthe building.

The extent to which any of these measuresare necessary is dependent on the use of thebuilding and, in some cases, its size, and on thelocation of the element of construction.

Introduction

B3.i Guidance on loadbearing elements ofstructure is given in Section 4. Section 5 isconcerned with the sub-division of a buildinginto compartments, and Section 6 makesprovisions about concealed spaces (or cavities).Section 7gives information on the protection ofopenings and on fire-stopping which relates tocompartmentation and to fire spread in concealedspaces. Common to all these sections and toother provisions of Part B, is the property of

fire resistance.

Fire resistance

B3.ii The fire resistance of an element ofconstruction is a measure of its ability towithstand the effects of fire in one or more ways,

f ll

function of a floor, are not trstructure. External walls, su

other forms of cladding whiweight and wind loads and load, are not regarded as lopurposes of B3.ii(a), althougfire resistance to satisfy reqSections 8 to 9).

Loadbearing elements may fire-separating function. Simelements may or may not b

Guidance elsewhere in theDocument concerning fire

B3.iv There is guidance in the use of fire-resisting consmeans of escape. There is gabout fire resistance of extethe spread of fire between bgives information on methodperformance for elements oAppendix B gives informatioAppendix C gives informatiomeasurement. Appendix D gon purpose group classificagives definitions.

Guidance

S


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Introduction4.1 Premature failure of the structure can beprevented by provisions for loadbearing elementsof structure to have a minimum standard of fireresistance, in terms of resistance to collapse orfailure of loadbearing capacity. The purpose inproviding the structure with fire resistance isthreefold, namely:

a. to minimise the risk to the occupants, someof whom may be unable to make their ownescape if they have become trapped or injured;

b. to reduce the risk to firefighters, who may beengaged in search or rescue operations; and

c. to reduce the danger to people in the vicinityof the building, who might be hurt by fallingdebris or as a result of the impact of thecollapsing structure on other buildings.

Fire resistance standard

4.2 Elements of structure such as structuralframes, beams, columns, loadbearing walls(internal and external), floor structures and gallerystructures should have at least the fire resistancegiven in Appendix A, Table A1.

Application of the fire resistance standards forloadbearing elements

4.3 The measures set out in Appendix Ainclude provisions to ensure that where oneelement of structure supports or gives stabilityto another element of structure, the supportingelement has no less fire resistance than the otherelement (see notes to Table A2). The measuresalso provide for elements of structure that arecommon to more than one building orcompartment, to be constructed to the standardof the greater of the relevant provisions. Specialprovisions about fire resistance of elements ofstructure in single storey buildings are also givenand there are concessions in respect of fireresistance of elements of structure in basements

b. the lowest floor o

Additional guidance

4.5 Guidance in oApproved Documentloadbearing wall is:

a. a compartment wcommon to two

b. a wall between aintegral garage, (s

c. protecting a mea(see Section 2); o

d. an external wall,

4.6 If a floor is alssee Section 5.

Floors in loft conve

4.7 In altering an efamily dwellinghousethe provisions in thisfor the floor(s), both 30 minute standard oAppendix A, Table Athe following conditio

a. only one storey i

b. the new storey chabitable rooms;

c. the total area of amount to more

then the existing firsaccepted if it has at standard of fire resiswhere the floor sepa

circulation spaces).Notes:

1. The modifiedsatisfies the test critin respect of loadbeareduced performanc

Section 4: Loadbearing elementsof structure

S ti 5 C t t tiB3


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Introduction

5.1 The spread of fire within a building can berestricted by sub-dividing it into compartmentsseparated from one another by walls and/orfloors of fire-resisting construction. The objectis twofold:

a. to prevent rapid fire spread which could trapoccupants of the building; and

b. to reduce the chance of fires becominglarge, on the basis that large fires are more

dangerous, not only to occupants and fireand rescue service personnel, but also topeople in the vicinity of the building.Compartmentation is complementary toprovisions made in Section 2 for the protectionof escape routes, and to provisions made inSections 8 to 10 against the spread of firebetween buildings.

Provision of compartmentation5.2 Compartment walls and compartmentfloors should be provided in the circumstancesdescribed below, with the proviso that thelowest floor in a building does not need to beconstructed as a compartment floor. Provisionsfor the protection of openings in compartmentwalls and compartment floors are given inparagraph 5.13 and Section 7.

5.3 Every wall separating semi-detachedhouses, or houses in terraces, should beconstructed as a compartment wall and thehouses should be considered as separatebuildings.

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

5.5 Where a door is provided between adwellinghouse and the garage, the floor of thegarage should be laid to fall to allow fuel spills toflow away from the door to the outside. Alternatively,the door opening should be positioned at least100mm above garage floor level

Note: Timber beams, joistsmay be built into or carried or concrete compartment wthem are kept as small as pfire-stopped. If trussed raftethey should be designed sopart of the truss due to a fire

will not cause failure of any another compartment.

Compartment walls betwe

5.7 Compartment walls ttwo or more buildings shoulof the building in a continuoThus adjoining buildings shoseparated by walls, not floo

5.8 Compartment walls ibeneath a roof should be cothe roof space (see definitioin Appendix E).

Junction of compartment

Section 5: Compartmentation

Diagram 10 Separatio

garage anSee paras 5.4 and 5.5

COMPARTMENTATION


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Junction of compartment wall with roof

5.11 A compartment wall should be taken up tomeet the underside of the roof covering or deck,with fire-stopping where necessary at the wall/

roof junction to maintain the continuity of fireresistance. The compartment wall should alsobe continued across any eaves.

5.12 If a fire penetrates a roof near a compartmentwall there is a risk that it will spread over the roofto the adjoining compartment. To reduce thisrisk either:

a. the wall should be extended up through theroof for a height of at least 375mm above the

top surface of the adjoining roof covering(see Diagram 11a). Where there is a heightdifference of at least 375mm between tworoofs or where the roof coverings on eitherside of the wall are AA, AB or AC this heightmay be reduced to 200mm; or

b. a zone of the roof 1500mm wide on eitherside of the wall should have a covering ofdesignation AA, AB or AC. Any combustible

boarding used as a substrate to the roofcovering, wood wool slabs, or timber tilingbattens that are carried over the compartmentwall should be fully bedded in mortar or othersuitable material over the width of the wall(see Diagram 11b).

Note:Double-skinned insulated roof sheetingwith a thermoplastic core should incorporate aband of material of limited combustibility at least

300mm wide centred over the wall.

Openings in co

Openings in compabuildings or occupa

5.13 Any openingsis common to two orlimited to those for:

a. a door which is nof escape in cassame fire resistathe wall (see Appfitted in accordanAppendix B; and

b. the passage of aprovisions in Sec

Doors

5.14 Information onAppendix B.

B3 COMPARTMENTATION


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X

X

The wall should be extended up through the roof for

least 375mm above the top surface of the adjoining

Where there is a height difference of at least 375mm

roofs or where the roof coverings on either side of th

or AC the height of the upstand/parapet wall above t

may be reduced to 200mm.

Roof covering to be designated AA, AB or AC for at

Boarding (used as a substrate), wood wool slabs or t

may be carried over the wall provided that they are fu

mortar (or other no less suitable material) where over

Thermoplastic insulation materials should not be car

Double-skinned insulated roof sheeting with a therm

should incorporate a band of material of limited com300mm wide centred over the wall.

Sarking felt may also be carried over the wall.

If roof support members pass through the wall, fire p

members for a distance of 1500mm on either side of

needed to delay distortion at the junction (see note t

Fire-stopping to be carried up to underside of roof co

or slab.

a.

b.

Section XX

Roof covering to be designated AA, AB or AC for at

side of wall.

Roofing battens and sarking felt may be carried over

Fire-stopping to be carried up to underside of roof co

below sarking felt.

Notes

1 Fire-stopping should be carried over the full thickn2 Fire-stopping should be extended into any eaves.

3 The compartment wall need not necessarily be co

Diagram 11 Junction of compartment wall with roof

See para 5.11

Section 6: Concealed spaces (ca


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Introduction

6.1 Concealed spaces or cavities in theconstruction of a building provide a ready routefor 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 moreobvious weakness in the fabric of the building.

Provision of cavity barriers

6.2 Provisions are given below for cavity

barriers in specified locations. The provisionsnecessary to restrict the spread of smoke andflames through cavities are broadly for the purposeof sub-dividing cavities, which could otherwiseform a pathway around a fire separating element,and closing the edges of cavities; thereforereducing the potential for unseen fire spread.See also paragraph 2.14.

Note: These should stopping details, see

Consideration shouldconstruction and fixifor these purposes aopenings in them shguidance on these is6.6 to 6.9 respective

6.3 Cavity barriersedges of cavities, inc(such as window and

cavity barriers shoulbetween an external cwall that separates band at the top of sucexcept where the caDiagram 13.

Section 6: Concealed spaces (ca

Diagram 12 Interrupting concealed spaces (cavities)

See para 6.3

B3 CONCEALED SPACES (CAVITIES)


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It is important to continue any compartment wallup through a ceiling or roof cavity to maintain thestandard of fire resistance therefore compartmentwalls should be carried up to the roof, seeparagraph 5.11. It is not appropriate to complete

a line of compartment walls by fitting cavitybarriers above them.

Double-skinned insulated roof sheeting

6.4 Cavity barriers need not be providedbetween double-skinned corrugated or profiledinsulated roof sheeting, if the sheeting is amaterial of limited combustibility; and bothsurfaces of the insulating layer have a surface

spread of flame of at least Class 0 or 1 (Nationalclass) or Class C-s3, d2 or better (Europeanclass) (see Appendix A); and make contact withthe inner and outer skins of cladding.

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

Construction and fix

cavity barriers

6.5 Every cavity barrier sto provide at least 30 minute

may be formed by any consanother purpose if it meets thbarriers (see Appendix A, Ta

However, cavity barriers in aor provided around opening

a. steel at least 0.5mm thic

b. timber at least 38mm th

c. polythene-sleeved minewool slab, in either casewhen installed in the cav

d. calcium silicate, cementbased boards at least 12

Note: Cavity barriers providmay be formed by the windif the frame is constructed oof the minimum thickness in

as appropriate.

6.6 A cavity barrier shoube tightly fitted to a rigid comechanically fixed in positiopossible (for example, in thewith slates, tiles, corrugatedmaterials) the junction shouProvisions for fire-stopping a

6.7 Cavity barriers shouldthat their performance is unineffective by:

a. movement of the buildinshrinkage or temperaturmovement of the externto wind; and

b. collapse in a fire of any them; and

c. failure in a fire of their fixbelow); and

d. failure in a fire of any mawhich they abut. (For exaceiling is continued over

Diagram 13 Cavity walls excludedfrom provisions forcavity barriers

See para 6.3

O i i it b i

CONCEALED SPACES (CAVITIES)


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Openings in cavity barriers

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

a. doors which have at least 30 minutes fire

resistance (see Appendix B, Table B1, item1(a)) and are fitted in accordance with theprovisions of Appendix B;

b. the passage of pipes which meet theprovisions in Section 7;

c. the passage of cables or conduits containingone or more cables;

d. openings fitted with a suitably mounted

automatic fire damper; and

e. ducts which are fire-resisting or are fitted witha suitably mounted automatic fire damperwhere they pass through the cavity barrier.

Section 7: Protection of openingsB3


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Introduction7.1 Sections 7 and 8 make provisions forfire-separating elements and set out thecircumstances in which there may be openingsin them. This section deals with the protectionof openings in such elements.

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

7.3 The measures in this section are intendedto delay the passage of fire. They generally havethe additional benefit of retarding smoke spreadbut the test specified in Appendix A for integritydoes not directly stipulate criteria for thepassage of smoke.

7.4 Consideration shouldthe effect of services that mconstruction that could advresistance. For instance, whloudspeakers and other elecinstalled, additional protectito maintain the integrity of a

7.5 Detailed guidance onfire doors is given in Appen

Openings for pipes

7.6 Pipes which pass threlements (unless the pipe isshould meet the appropriatealternatives A, B or C below

Alternative A: Proprietary (any pipe diameter)

7.7 Provide a proprietaryhas been shown by test to mresistance of the wall, floor

Alternative B: Pipes with a

7.8 Where a proprietary sused, fire-stopping may be keeping the opening as smanominal internal diameter of

not be more than the relevain Table 3.

Section 7: Protection of openingsand fire-stopping

Table 3 Maximum nominal internal diameter of pipes passing throua fire separating element(see paragraph 7.6 to 7.9)

Pipe material and maximum nominal int

Situation (a)

Non-combustiblematerial (1)

(b)

Lead, aluminiumaluminium alloy,uPVC (2), fibrecement

1. Wall separating dwellinghouses 160 160 (stack pipe) (3

Alternative C: sleeving

PROTECTION OF OPENINGS AND FIRE-STOPPING


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Alternative C: sleeving

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

Diagram 14 Pipes penetratingstructure

Notes:

1 Make the opening in the structure as small

as possible and provide fire-stopping

between pipe and structure.

2 See Table 3 for materials specification.

See para 7.9, alternative method C

Diagram 15 Encwat

Notes:

1 The enclosure should

a. be bounded by a c

outside wall, an int

specification at 2 b

b. have internal surfac

Class 0 (National c

(European class) N

s3, d2, this mean

smoke production

c. not have an access

circulation space o

d. be used only for dr

pipes for a drainag

2 The casing should:

a. be imperforate exc

access panel;

b. not be of sheet me

c. have (including any

minutes fire resista

3 The opening for a pipcasing, should be as

around the pipe.

See para 7.8

B3 PROTECTION OF OPENINGS AND FIRE-STOPPING


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7.11 If a flue or duct containing flues orappliance ventilation duct(s), passes through acompartment wall or compartment floor, or isbuilt into a compartment wall, each wall of theflue or duct should have a fire resistance of atleast half that of the wall or floor in order toprevent the by-passing of the compartmentation(see Diagram 16).

Fire-stopping7.12 In addition to any other provisions in thisdocument for fire-stopping:

a. joints between fire-separating elementsshould be fire-stopped; and

b. all openings for pipes, ducts, conduitsor cables to pass through any part of afire-separating element should be:

i. kept as few in number as possible; and

ii. kept as small as practicable; and

iii. fire-stopped (which in the case of a pipeor duct should allow thermal movement).

7 13 To prevent displacement materials used

7.14 Proprietary fire-stoppsystems, (including those dpenetrations) which have bemaintain the fire resistance element, are available and m

Other fire-stopping material

cement mortar;

gypsum-based plaster;

cement-based or gypsuperlite mixes;

glass fibre, crushed rocor ceramic-based produresin binders); and

intumescent mastics.

These may be used in situathe particular material. Not

suitable in every situation.Guidance on the process ofand maintenance of passiveavailable in Ensuring Best PFire Protection in Buildings (produced by the Associatio

Diagram 16 Flues penetrating compartment walls or floors(note that there is guidance in Approved Document J conceadjacent to compartment walls)

See para 7.11

The RequirementEXTERNAL FIRE SPREAD


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This Approved Document deals with thefollowing Requirement from Part B of Schedule 1to the Building Regulations 2000 (as amended).

Requirement Limits on applicat

External fire spread

B4. (1) The external walls of the building shall adequately

resist the spread of f ire over the walls and from one buildingto another, having regard to the height, use and position of

the building.

(2) The roof of the building shall adequately resist the

spread of fire over the roof and from one building to another,

having regard to the use and position of the building.

The Requirement

GuidanceB4


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Performance

In the Secretary of States view the Requirements

of B4 will be met:

a. if the external walls are constructed so thatthe risk of ignition from an external source,and the spread of fire over their surfaces, isrestricted by making provision for them tohave low rates of heat release;

b. if the amount of unprotected area in the sideof the building is restricted so as to limit the

amount of thermal radiation that can passthrough the wall, taking the distance betweenthe wall and the boundary into account; and

c. if the roof is constructed so that the risk ofspread of flame and/or fire penetration froman external fire source is restricted.

In each case so as to limit the risk of a firespreading from the building to a building beyondthe boundary, or vice versa.

The extent to which this is necessary is dependenton the use of the building, its distance from theboundary and, in some cases, its height.

Introduction

External walls

B4.i The construction of external walls and the

separation between buildings to prevent externalfire spread are closely related.

The chances of fire spreading across an openspace between buildings, and the consequencesif it does, depend on:

a. the size and intensity of the fire in thebuilding concerned;

b. the distance between the buildings;

c. the fire protection given by their facingsides; and

d. the risk presented to people in the otherbuilding(s).

B4 ii Provisions are made in Section 8 for the

Guidance

Section 8: Construction of extern


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Introduction

8.1 Provisions are made in this section for the

external walls of the building to have sufficientfire resistance to prevent fire spread across therelevant boundary. The provisions are closelylinked with those for space separation in Section 9which sets out limits on the amount of unprotectedarea of wall. As the limits depend on the distanceof the wall from the relevant boundary, it ispossible for some or all of the walls to have nofire resistance, except for any parts which are

loadbearing (see paragraph B3.iii).External walls are elements of structure and therelevant period of fire resistance (specified inAppendix A) depends on the use, height and sizeof the building concerned. If the wall is 1000mmor more from the relevant boundary, a reducedstandard of fire resistance is accepted in mostcases and the wall only needs fire resistancefrom the inside.

8.2 Provisions are also made to restrictthe combustibility of external walls of buildingsthat are less than 1000mm from the relevantboundary. This is in order to reduce the surfacessusceptibility to ignition from an external source.

In the guidance to Requirement B3, provisionsare made in Section 4 for internal and externalloadbearing walls to maintain their loadbearingfunction in the event of fire.

Fire resistance standard

8.3 The external walls of the buildingshould have the appropriate fire resistancegiven in Appendix A, Table A1, unless theyform an unprotected area under the provisionsof Section 9.

External surfaces8.4 The external surfaces of walls within1000mm of the relevant boundary should meetClass 0 (National Class) or Class B-s3,d2 or better(European class). The total amount of combustiblematerial on walls more than 1000mm from the

Section 9: Space separationB4


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Introduction

9.1 The provisions in this Section are based

on a number of assumptions and, whilst someof these may differ from the circumstancesof a particular case, together they enable areasonable standard of space separation tobe specified. The provisions limit the extentof unprotected areas in the sides of a building(such as openings and areas with a combustiblesurface) which will not give adequate protectionagainst the external spread of fire from one

building to another.A roof is not subject to the provisio

BR App Doc B Vol 1

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