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Design, Installation and Maintenance of Fire

Detection and Alarm Systems in Dwellings

ELECTRONIC F IRE &SEC

UR

ITY

SYST

EM

S

Fire & Security Association, ESCA House, 34 Palace Court, London W2 4HY T 020 7313 4888 F 020 7221 7344 E [email protected]

www.fireandsecurityassociation.co.uk

Supporting the Profession to Safeguard the Client

The FSA Short Guide Series

Smoke Alarms, Fire Detection and Alarm Systems in Dwellings

An Introduction to BS 5839-6:2004and the associated legislative framework

The FSA is a specialist division of the ECA.

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CONTENTS

1. Introduction.............................................................................................3

2. Legislation ..............................................................................................3

3. The Building Regulations 2007 .................................................................4

4. Fire Risk Assessment ...............................................................................6

5. System Definitions, Grades and Categories .................................................7

6. Types of Detector ...................................................................................14

7. Location and Positioning of Fire Detectors ................................................15

8. Limitation of False Alarms.......................................................................18

9. Wireless Fire Detection and Alarm Systems ..............................................18

10. Alarm Systems for the Deaf and Hearing Impaired.....................................19

11. Audibility of Fire Alarm Warning Devices ..................................................20

12. Zoning of Systems..................................................................................21

13. Wiring and Installation ...........................................................................22

14. Maintenance and Servicing .....................................................................23

15. System Certification ...............................................................................24

16. Example Certificates...............................................................................25

17. Documentation ......................................................................................27

18. References ............................................................................................27

19. FSA Training Courses..............................................................................28

20. Frequently Asked Questions ....................................................................28

1. Introduction

There have been many books published as detailed guides to BS 5839 and its many parts,some of which extend to more than 200 pages. In this document, we are focusing onclarifying some of the more popular issues and the questions which are commonly asked bydesigners, installers and maintenance personnel.

This guide is not a substitute for BS 5839-6: 2004 nor a definitive guidance document. Anyonewho intends to design, install, commission or maintain domestic fire detection and alarm systems,should hold a current authorised copy of the standard. They should also ensure that theyhave a sound understanding of the legislation, that applies, to all forms of domestic dwelling.

It is important to be aware that BS 5839-6 states, “Compliance with a British Standarddoes not in itself confer immunity from legal obligations. In particular, attention is drawn toBuilding Regulations and, in cases of Houses of Multiple Occupation, to the relevant housinglegislation. Guidance on Building Regulations is given in Approved Document B in Englandand Wales, the Technical Standards that support the relevant building regulations inScotland and in Technical Booklet E in Northern Ireland”.

2. Legislative Framework

The Fire Safety Order 2005 (FSO) and the implications affecting BS 5839-6:2004 recommendations

The FSO and the parallel Scottish legislation the Fire Safety (Scotland) Regulations 2006(FSSR) do not apply to single-family dwellings. However, they do apply to Houses of MultipleOccupation (HMO), flats and maisonettes constructed to current building regulations.

Prior to October 2006, these HMOs, flats, and maisonettes required a fire certificate. Today allof these dwellings require a fire risk assessment, which must be provided by the “responsibleperson”. This is the person who has day-to-day responsibility for the building. In the case of theHMO and blocks of flats, this will be either the landlord or the agent responsible for the building.Therefore, before undertaking the design of the fire detection and alarm system, the installershould obtain a copy of the building’s fire risk assessment from the responsible person. This willidentify the grade and category of system that needs to be installed in that particular building.

The responsible person for the premises is required by law to provide a fire riskassessment. In many cases the installer will find that no fire risk assessment has been

Acknowledgements

The FSA would like to thank the following organisations for assistance with materialsand pictures used in this document.

AICO Smoke Alarms and Accessories 0870 758 4000

D-LINE Mini trunking with integral clips 0191 293 0909

DRAKA Fire-resistant clips 01332 345431

GENT Control and Indicating panels 01162 462000

In 2004 when the standard was written, around 80% of all fire deaths and injurieswere in dwellings and totalled 450-500 deaths and 14,000 injuries per annumrespectively. The fatality rate in dwellings where there is no working smoke detectoris between two and three times the fatality rate in dwellings where a smoke detectoris present and functioning correctly.

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prepared for the building. In this case the installer must consider the risks involved inspecifying the Grade and Category of the system, unless he is able to demonstrate thathe is competent (a person with sufficient training, knowledge and experience andother qualities) to do so. Any person who contracts to carry out the fire riskassessment should meet these criteria, and also hold appropriate professionalindemnity insurance, which covers the work undertaken in the preparation of a firerisk assessment.

Special guidance documentation has been provided related to the FSO relating tosleeping risks in HMOs, flats and maisonettes constructed to current building regulations.This guidance differs from BS 5839-6. Since the FSO is legislation, this supersedesBS5839-6 recommendations.

On page 55 of the FSO guidance document. http://www.communities.gov.uk/documents/fire/pdf/151339 for sleeping risks, the normal HMO is treated differently from flats andmaisonettes, which are constructed to current building regulations. In these types ofdwelling each flat and maisonette will be a separate fire compartment with fire seals onthe front door of each unit, and which open onto the common areas.

Note 4 of Table 1 states: “Flats and maisonettes constructed to current buildingregulations will not require automatic fire detection in common areas. However self-contained smoke alarms will normally be fitted in each accommodation unit”.

This may be varied where the fire risk assessments required by the FSO or a technicalspecification determines that the common areas pose a significant fire risk and should beprovided with a Grade A system L1 or LD1 system.

The Housing Act 2004 (THA) and the implications affecting BS 5839-6:2004 recommendations

The Housing Act 2004 (THA) applies to housing authorities and landlords and broughtin a new system of regulation for fire safety in existing residential premises with theHousing Health and Safety Rating System (HHSRS) and Licensing of HMOs, bothenforced by Local Housing Authorities (LHAs). Alongside this, the FSO imposed dutieson landlords and gave powers to the Fire and Rescue Services (FRS) in relation to thecommon areas of HMOs, flats and maisonettes and sheltered accommodation in whichcare is not provided, supporting the FSA and thereby introducing a dual enforcementregime in these types of premises.

3. The Building Regulations 2007

The installation of smoke alarms and automatic fire detectors is a requirement under PartB of the Building Regulations which relates to new and materially altered dwellings,which are governed under the auspices of building control. In most cases it also fallsunder the requirements of Part P relating to competence.

BS 5839-6 recommends that existing dwellings generally may have a lesser grade andcategory of system and still comply with national building regulations. However, in existingdwellings where the structural fire precautions are of a lower standard, the grade andcategory recommended is the same as that for new and materially altered dwellings. Itshould be noted that owner-occupiers of existing dwellings are not forced by law to installsmoke alarms. At this time they can only be advised to do so. However, as the installer ofa fire detection and alarm system you have a duty of care to your customer to ensure thatthe system that you provide is fit for purpose.

Note: The FSO (fire risk assessment), Building Regulations (new and materially altered premises)and THA (requirements for LHAs and landlords) supersede all earlier fire safety legislation.

What does British Standard BS 5839: Part 6: 2004 recommend?

This is the definitive Code of Practice specified within the Building Regulations to whicharchitects, building professionals, enforcing authorities, landlords and installers should referfor recommendations on the design, installation, commissioning, maintenance and use ofsmoke and heat alarms in domestic dwellings.

BUILDING REGULATIONS PART B: THE REQUIREMENTMeans of warning and escape

B1. The building shall be designed and constructed so that there are appropriateprovisions for the early warning of fire, and appropriate means of escape in case offire from the building to a place of safety outside the building capable of being safelyand effectively used at all material times.

Requirement B1 does not apply to any prison provided under Section 33 of thePrison Act 1952 (power to provide prisons, etc).

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4. Fire Risk Assessment

BS 5839-6 recommends that a Fire Risk Assessment be carried out prior to installingfire detection and alarm systems. Section 4 and Appendix A of BS 5839-6 provideextensive guidance on how this assessment should be carried out. The FSO requires thatthis should be carried out by a competent person.

For Houses of Multiple Occupation (HMO), flats, and sheltered housing, either thelandlord or the managing agent should provide the fire risk assessment. This individualis called the “Responsible Person”. It is he who must provide the installer with the clearinformation related to the Grade and Category of the system, which is to be installed inthat particular building. The contractor then takes responsibility for the design of thesystem in accordance with the information provided within the fire risk assessment andin accordance with BS 5839-6: 2004.

Where properties are rented, the landlord has a legal duty of care for the safety of histenants. Not only must he deal with the issue of fire safety in the common areas, hemust also accept responsibility for the individual rented units.

For a single-family dwelling unit e.g. house or bungalow, the householder would not beexpected to provide a fire risk assessment. In the event that there is no fire riskassessment available, then reference should be made to BS 5839-6 Tables 1 and 2 inSection 9, Choice of systems. These tables can be used to determine the grade andcategory of system needed for each particular dwelling. A guide is provided below.

5. System Definitions, Grades and Categories

BS 5839-6: 2004 is unlike BS 5839-1: 2002 in that it is not a prescriptive standard, butis based on the principal of risk assessment. The descriptions recommended below, whichare derived from Table 1 should be regarded as base guidelines and are appropriate forpremises of normal risk. Where the risk is higher or indeed lower, then a higher or lowerlevel of detection and warning may be appropriate.

Six different grades of fire detection system are defined and, generally speaking, the greaterthe fire risk, the more comprehensive the system should be. Briefly, the grades are as follows:

GRADE A A full system with control and indicating equipment installed to BS 5839: - 1GRADE B Detectors and sounders using simpler specified equipment.GRADE C Detectors and sounders or alarms with central controlGRADE D Interlinked mains powered smoke alarms with an integral standby power supplyGRADE E Interlinked mains powered smoke alarms with no standby supplyGRADE F Battery powered smoke alarms

There are two system definitions covered by BS 5839-6: 2004:

1. Life safety systems which cover sleeping risks Definition - L2. Property protection systems which generally cover insurable risks Definition - P

Three different categories of life protection system are defined. Briefly, these are (starting atthe highest):

LD1/PD1 Alarms in all circulation spaces that form part of escape routes and all areas where a fire might start, but not bathrooms, shower rooms or toilets

LD2/PD2 Alarms in all circulation spaces that form part of escape routes and rooms or areas that present a high fire risk

LD3/P Alarms in circulation spaces that form part of escape routes

The Code emphasises that no one type of alarm is most suitable for all applications.Consideration must be given to the most suitable type of detection - optical, ionisation orheat detection.

What do Building Regulations require for dwellings?

Fire detection and alarm systems in most dwellings should be installed in accordancewith the recommendations of BS 5839-6 or as required by local Building Control orFire Officers.

Architects, builders, engineers, contractors and installers must comply with BuildingRegulations and install battery-mains-powered smoke alarms or fire detection and alarmsystems in new and materially altered dwellings, existing rented maisonettes, rented twostorey houses, three or more storey houses, and houses of multiple occupation (HMO)

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Grades and Categories of System - Clause 9 Table 1 and Annex B of BS 5839-6

Grade A, LD1 HMOs, Single-family dwellings and shared houses with one or more floorsgreater than 200sq metres. (Note: FSO guidance for sleeping risks allows HMOs of morethan two storeys (more than one storey above ground), flats and conversions (includingholiday flats) that have not been constructed to building regulation standards may have anLD2 category of system installed.)

These dwellings consist of - Three or more storey houses. Houses of Multiple Occupation - Communal areas only.

• Conventional or addressable control and indication panel with battery back-up(conforming with EN 54-2 and EN 54-4) covering the communal areas

• Where rented individual flats are included these systems should be self-contained andinstalled to Grade D LD2 standard

• System is designed in accordance with the recommendations of BS 5839-1 sections 1-4, withBS 5839-6 clauses 13,14,18,15.20 and 21 replacing the similar clauses of BS 5839-1

• Fire detectors in all the communal areas (the fire risk assessment may define that aheat detector and sounder should be located inside each flat, within 1 metre of themain door and directly connected to the communal system)

• Manual call points should be sited on the fire exit route of the common parts at allstorey exits and to the open air

• May be interconnected using radio links

• The communal system should be wired in standard or enhanced fire-resistant cable;this includes the mains supply

• The communal system should have its own dedicated mains supply

• The independent system in each flat may derive its mains supply from a dedicatedsupply or a regularly used local lighting circuit

• Each system in the flats may be wired in non-fire-resistant cable

• If a conventional control and indicating panel is used, a remote indicator should belocated outside the flat or the flat number or the location should be indicated in text onan addressable control and indication panel

• The sound pressure level of the alarm signal measured at the doorway of eachbedroom with the door open should be at least 85dB(A), unless a fire risk assessmentdetermines that the sound pressure level should be higher. 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation orliving space a smoke detector may be used, subject to a fire risk assessmentestablishing that the kitchen extract system will be able to prevent false alarms beingcaused by food preparation

• Depending on the fire risk assessment the communal system may be connected to analarm receiving centre (ARC)

Grade A, PD1 as LD1 above. PD2 Property protection of dwellings only where specified(no sleeping risk), see recommendations below. This is usually for insurance purposes.

• Conventional or addressable control and indication panel with battery back-up(conforming with EN 54-2 and EN54-4)

• System generally specified by insurers and is solely for the protection of the property

• System is designed in accordance with the recommendations of BS 5839-1 sections 1-4with BS 5839-6 clauses 13,14,18,15.20 and 21 replacing those of BS 5839-1

• Fire detectors in a PD2 system would be installed in defined areas of the building. Onthe rare occasion that a PD1 system is specified the detectors would be locatedthroughout the building except toilets, bath and shower rooms


• Should be wired in standard or enhanced fire-resistant cable; this includes the mains supply

• System should have its own dedicated mains supply

• The system will generally have a minimum of two sounders, one of which will be onthe external face of the building adjacent to the control and indication panel

• Will be connected to an alarm receiving centre (ARC)

Grade B, LD2 New or materially altered dwellings or existing dwellings where structuralfire precautions are of a lower level. Single-family dwellings and shared houses with nofloor greater than 200sq metres in area. These consist of four or more storey houses.

New or materially altered dwellings or existing dwellings where structural fire precautionsare of a lower level. Single-family dwellings and shared houses with one or more floorgreater than 200sq metres in area. These consist of maisonettes or two-storey houses.

• With the exception of the indicator panel the system should conform to BS 5839-1,and may accommodate fire detectors other than smoke and heat alarms

• Basic indication panel with battery back-up (conforming with EN 54-2, EN54-4 or annexC of BS 5839-6); this is not a standard panel; Consider using standard conventional firealarm panel as used for Grade A system. This may be more competitive

• Optical alarms in hallways and landings, heat detectors in the kitchen and lounge.(Additional detectors may be needed subject to the fire risk assessment)


• Should be wired in standard fire-resistant cable, particularly for the mains supply



• Where the design of the flat has no door separating the kitchen from the circulation or livingspace a smoke detector may be used, subject to a fire risk assessment establishing that thekitchen extract system will be able to prevent false alarms being caused by food preparation

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Grade C, LD1 Houses providing NHS supported living in the community. Dwellings of one,two or three storeys occupied by no more than six residents. Other dwellings of this usage- see Grade A, Category LDI above.

• Control and indication panel with battery back-up for use in sheltered housing

• Intruder alarm system may also support 12 Volt smoke and heat alarms

• Social alarm system may also support 12 Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system.

• System is designed in accordance with the recommendations of BS 5839-1 Sections 1-4 withBS 5839-6 clauses 13,14,18,15.20 and 21 replacing the similar clauses of BS 5839-1

• Fire detectors in all the communal areas (the fire-risk assessment may define that aheat detector and sounder should be located inside each flat, within 1 metre of themain door and directly connected to the communal system)

• Manual call points may be sited on the fire exit route of the common parts, at allstorey exits and to the open air


• May be wired in standard non-fire resistant cable

• Requires a dedicated mains supply

• The sound pressure level of the alarm signal measured at the doorway of eachbedroom with the door open should be at least 85dB(A), unless a fire risk assessmentdetermines that the sound pressure level should be higher 75dB(A) at the bed head

• Where the design of the flat has no door separating the kitchen from the circulation or livingspace, a smoke detector may be used, subject to a fire risk assessment establishing that thekitchen extract system will be able to prevent false alarms being caused by food preparation

• Intruder and social alarm systems may be considered for connecting to an alarmreceiving centre (ARC)

Grade C, LD2 Sheltered housing (individual dwelling units only) - New or materially altereddwellings or existing dwellings where the structural fire precautions are of a lower standard.

• Control and indication panel with battery back-up for use in sheltered housing.

• Intruder alarm system may also support 12Volt smoke and heat alarms

• Social alarm system may also support 12Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system

• Optical alarms in hallways and landings, heat detectors in the kitchen and lounge


• May be wired in standard non-fire-resistant cable


• The sound pressure level of the alarm signal measured at the doorway of eachbedroom with the door open should be at least 85dB(A), unless a fire risk assessment

determines that the sound pressure level should be higher. 75dB(A) at the bed head



Grade C, LD3 Sheltered housing (Individual dwelling units only) - Existing dwellings only.

• Control and indication panel with battery back-up for use in sheltered housing

• Intruder alarm system may also support 12Volt smoke and heat alarms

• Social alarm system may also support 12Volt smoke and heat alarms

• Carbon monoxide detectors can be added to the system

• Optical alarms in hallways and landings


• May be wired in standard non-fire-resistant cable


• The independent system in each unit should derive its mains supply from a dedicated supply




Grade C, PD2 Property protection only where specified.

These consist of - Single or two-storey dwellings. Other dwellings as PD1.

• Control and indication panel with battery back-up for use in sheltered housing.

• System is used solely for the protection of the property

• Fire detectors in a PD2 system would be installed in specified areas of the building.


• May be wired in standard cable


• The system will generally have a minimum of two sounders, one of which will be onthe external face of the building adjacent to the control and indication panel

• Will be connected to an alarm receiving centre (ARC)

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Grade D, LD2 This is the most commonly used grade and category.

Single-family dwellings and shared houses with no floors greater than 200sq metres - Newor materially altered dwellings and existing dwellings where the structural fire precautionsare of a lower standard. (Note: The FSO guidance document for sleeping risks allowsHMOs and small premises e.g. bed and breakfast of up to two storeys (up to one floorabove ground) with no floor greater than 200sq metres to have Grade D LD2 systems butthis does not need to be interconnected with the common areas of the building.)

These dwellings consist of owner occupied bungalow, flat or other single storey unit, rentedbungalow, flat or other single-storey unit. Owner occupied maisonette or owner occupiedtwo-storey house, rented maisonette or rented two-storey house. Three-storey house or anexisting four storeys or more house, unaltered with sound structural fire precautions.

Single-family dwellings and shared houses with one or more floors greater than 200sq metres.

New or materially altered or, existing dwellings, where structural fire precautions are of alower standard.

These dwellings consist of bungalow, flat or other single-storey unit.

New or materially altered HMOs or HMOs with no floors greater than 200sq metres, orwhere structural fire precautions are of a lower standard.

These dwellings consist of HMOs of one or two storeys and individual dwelling units,within the HMO, comprising of two or more rooms.

• Mains powered smoke and heat alarms with battery back-up

• Optical smoke alarms in hallways and landings, heat alarms in the kitchen and lounge

• Heat alarms as best suited for the particular circumstance in the main living room toprevent false alarms

• All smoke and heat alarms should be interconnected, including those using wireless(radio) links

• Grade D type alarms may be connected to a local frequently used lighting circuit or beserved by a dedicated circuit

• Standard domestic cable may be used for this grade of system

• The sound pressure level of the alarm signal measured at the doorway of eachbedroom with the door open should be at least 85dB(A), unless a fire risk assessmentdetermines that the sound pressure level should be higher. 75dB(A) at the bed head.


Grade D, LD3 This grade and category applies to existing dwellings only.

Existing single-family dwellings and shared houses with no floor greater than 200sq metres.

These consist of rented maisonette or rented two-storey house. Three-storey house (Note:

The FSO guidance document for sleeping risks allows HMOs and small premises e.g. bedand breakfast of up to two storeys (up to one floor above ground) with no floor greater than200sq metres may have Grade D LD3 but this does not need to be interconnected withthe common areas of the building).

Existing single-family dwellings and shared houses with one or more floors greater than200sq metres.

These dwellings consist of bungalow, flat or other single-storey unit.

• Mains powered smoke and heat alarms with battery back-up

• Optical alarms in circulation spaces - hallways and landings

• If a fire risk assessment shows the property or occupier to be a high fire risk, or thestructural fire precautions are of a lower standard increase the number of alarmsinstalled to meet the risk - e.g. follow new build recommendations for an LD2installation

• All alarms should be interconnected. Mains powered smoke and heat alarms may beinterconnected using radio links

• Mains powered smoke and heat alarms with battery back-up may be wired to afrequently used lighting circuit or a dedicated circuit



Grade E, LD3 See Grade D LD3 above

• Grade E “mains only” systems are contained in BS 5839 but are almost never used.The failure of the mains supply will prevent this grade of system from working.Professional installers should consider using Grade D systems in place of Grade E.

Grade F, LD3 This grade and category applies to existing dwellings only.

• Battery powered with a minimum battery life of five years

• Optical smoke alarm in circulation spaces - hallway

• Where there is more than one, smoke alarms should be linked together by standarddomestic cable or wireless (radio)

The only buildings which may have battery-only smoke alarms, Grade F, are:

1. Existing owner occupied bungalow, flat or other single-storey units2. Existing rented bungalow, flat or other single-storey unit3. Existing owner occupier maisonette or other single-storey unit

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BS 5839-6: 2004 identifies a special occasion where Grade F systems should not beused. The proviso specifically relates to the above three types of building:

• Proviso. Use Grade E (see note on Grade E LD3 systems above) if there is any likelihoodthat the occupier may not be able to replace the battery following the battery low warningsignal on a Grade F system, or if there is a risk that the occupier is unable to pay fornew batteries. In these situations, then mains powered smoke alarms should be used.

Important note:

Even though BS 5839-6 permits the use of battery powered smoke alarms, the aboverecommendations are really intended to allow the owner-occupier to buy and fit a low-costsmoke alarm, on the basis that something is better than nothing.

Due to the popularity of Grade D smoke alarms, Grade E smoke alarms are not alwaysreadily available. The professional installer should give careful consideration to avoiding theuse of Grades E and F smoke alarms, particularly when Grade D mains/battery poweredsmoke alarms are readily available and are less prone to the problems identified above.

However, some local building control officers administering the Building Regulations willaccept the use of single Grade F smoke alarm in the above types of premises. Therefore,you should make time to consult them in order to determine the minimum requirementsprior to commencing the installation, or you could find yourself being uncompetitive. Youneed, however, to assess the risk to your customer when selecting particular grades andcategories of system. Regardless of the opinions of others, the person installing the systemhas a duty of care to ensure that the system he provided is fit for purpose.

6. Types of Detector

Optical Alarms - where should they be used?

Optical sensors are more responsive to smouldering fires producing large particle smoketypical of fires involving furniture and bedding. They are more immune to invisible smokeproduced by ‘burning the toast’ and similar cooking fumes. This makes them ideal forlocating in hallways close to kitchens, where false alarms from ionisation alarms may be aparticular problem. BS 5839: Pt.6: 2004 recommends the use of optical alarms incirculation spaces of a dwelling, such as hallways and landings. Optical alarms are proneto false alarm if exposed to steam and should not be located too close to poorly ventilatedbathrooms or shower rooms.

1. A light beam is pulsed in the sensor chamber every 10 seconds to ‘look’ for smoke.Any smoke present has to be visible to the naked eye so that the receptor can ‘see’ it.If no smoke is detected, the alarm will remain in a standby state.

2. When large particle smoke is detected, the light beam will be scattered onto the lightreceptor.

3. This will then send an electrical signal to the Integrated Circuit (IC).

4. If the IC receives two consecutive signals, the alarm will sound.

Heat Alarms - where should they be used?

Heat alarms are less likely to cause false alarm problems, as they are not responsive toany type of smoke or fumes. They only detect heat. This type of detector will provide aslower response than smoke alarms. All of the alarm units should be inter connected.

BS 5839-6: 2004 recommends that heat alarms should be used in kitchens. It goes on tosuggest that they may also have a role to play in the main living room but they should notbe installed in circulation spaces or areas where fast response to fire is required.

1. A thermistor (a heat sensitive resistor) is sited in the sensor chamber of the alarm.

2. When heat is detected the thermistor will send an electrical signal to the IntegratedCircuit (IC).

3. If the IC receives two consecutive signals the alarm will sound.

Ionisation Alarms - where should they be used?

Ionisation sensors are particularly sensitive to the almost invisible smoke produced by fastflaming fires. This makes them more liable to false alarm due to cooking fumes if sited in ahallway close to a kitchen. Ionisation alarms are less vulnerable to false alarms caused bydense tobacco smoke, excessive dust or insect ingress. BS 5839: Pt.6: 2004 recommendsthat ionisation alarms should not be used in hallways and landings, where there is a risk offalse alarms caused by cooking fumes.

1. An Ionisation detector is designed to provide an early warning of a fast burning fire (notsmoke). The ionisation device has two electrodes within an ionisation chamber,between which a measured resistance of negative ions flow. This circuit is connected toa potential divider in the Integrated Circuit (IC), which remains in a constant closedstandby state.

2. In consuming fuel, fire creates combustion gas, which gives off positive ions. Whenthese positive ions enter the ionisation chamber, the positive ions join themselves tothe negative ions flowing from the radioactive source and between the electrodes,changing the resistance of the flow.

3. The resistance is applied to the potential divider in the IC and allows current to flow.

4. If the IC receives a continuous signal, the alarm will sound.

7. Location and Positioning of Fire Detectors

When siting detectors in a hallway, no smoke detector should be more than 7.5 metreshorizontally from any point in the hallway. In rooms, again no smoke detector should

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be sited more than 7.5 metres from any point of the room. For heat detection, thisdistance should be reduced to 5.3 metres. No smoke alarms should be installed lessthan 300mm from any wall or beam. In a room or hallway, 10m x 10m or 50 m2

where ceiling mounting is impractical, detectors may be mounted on the wall between150mm and 300mm from the ceiling. Do not install smoke or heat alarms inbathrooms, shower rooms or toilets, except where the fire risk assessment identifies aspecific need e.g. the presence of a boiler.

Which type of detector is suitable for mounting in any given location?

Average two-storey house

Single-storey dwelling

Note: For roofs with a pitch deeper than 600mm, smoke detectors should be within thetop 600mm and heat detectors within 150mm. Allow increased coverage over 7.5m forsmoke detectors and 5.3m for heat detector spacings due to the angle of the roof whichwill then be applicable at 1% for each degree of slope up to a maximum of 25%.

Typical three floor house (HMO) with flats and apartment units on each floor, installedto Grade A (BS 5839-1) Category LD3 in the units and L3 in the common areas

INDEX

Optical or Ionisation smoke alarm as best suited for the particular circumstances

Optical smoke alarm

Smoke or heat alarm as best suited for the particular circumstances

Heat alarm

Correct ceiling siting position for alarms

Do not install alarms here

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The diagram above shows a house converted into flats (HMO). In this typical system eachflat has its own dedicated system (see the symbol above). There is also a communalsystem, which covers the escape routes and rooms opening onto the escape routes.Should a false alarm occur in any of the flats, it will not affect any of the others.

Some specifiers require that if a flat is unoccupied and a fire occurs, a heat alarm insidethe flat (connected to the escape route system, but not the system in the apartments) willoperate the communal system in the escape routes plus the heat alarm adjacent to themain entrance door in each of the other flats, thus providing a vital early warning.

Please see guidance on the FSO requirements for flats and maisonettes constructed undercurrent building regulations. Unless the specification or fire risk assessment requires it,there is no need for smoke alarms or manual call points within the communal areas.

8. Limitation of False Alarms

The main problem for users and the Fire and Rescue Service are the false or unwantedalarms experienced with many fire alarm systems.

These cause inconvenience to the occupants and unnecessary call outs for the Fire andRescue Service. A common response from the occupant is to disable the system. Falsealarms put lives at increased risk, and waste valuable resources.

It is important when locating and positioning fire detectors that the risk of false alarms isconsidered. Annex D of BS 5839-6: 2004 covers false alarms and Section 3 of BS 5839-1devotes 13 pages of information to the subject of Limitation of False Alarms, which isbeyond the scope of this guide.

The ODPM (now CLG Communities and Local Government) in association with CFOA (ChiefFire Officers Association), produce a specific document relating to the reduction of false alarms.

This document can be downloaded free of charge at: -

http://www.eca.co.uk/_includes/Downloads/Technical/Fire%20and%20Security/ODPM%20False%20Alarm%20Booklet1.pdf

9. Wireless Fire Detection and Alarm Systems

Interconnection of smoke alarms and fire detection and alarm systems is an important elementsince it allows all of the sounder devices within the building to operate at the same time.

There are occasions when hard-wired interconnection will be impractical and indeedexpensive. In these situations current standards recommend the use of wireless (radio) forfire detection and alarm systems Grades A, B and C, as well as smoke alarm systems D, Eand F. This means that it is much easier to comply with the interconnection and extendedalarm coverage recommended in BS 5839-6.

10. Alarm Systems for the Deaf and Hearing Impaired

BS 5839-6 makes recommendations for people with hearing difficulties who require adifferent approach to fire protection, as a conventional alarm sounder will probably not besufficient for their needs.

Those with hearing difficulties will need to use strobe units and a vibrating pad locatedunder the pillow. This equipment can be connected to the Grade A, B, C or D systemseither by hard wire or wireless (radio) installation.

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11. Audibility of Fire Alarm Warning Devices

A fire detection and alarm system only providessatisfactory protection if it is capable of rousing atleast the principal occupants of the dwelling. It isknown that greater sound levels are required torouse children, older people with poor hearing andimpaired persons (alcohol and drugs). Internationaltests have shown that from these groups 120dB(A)has failed to wake some of those tested.

As we have identified earlier, BS 5839-6recommends 85dB(A) at the doorway of eachbedroom (with the door open). A closed door canreduce this by as much as 30dB(A). The documentdoes, however, go on to say that higher levels mayby required to rouse certain groups of people.

The international research regarding soundpressure levels suggests that 75dB(A) at the bedhead is a minimum sound pressure level and thateven this may not be enough. Whilst the text ofBS 5839-6 identifies this sound pressure level itmakes no specific further recommendation, statingonly that higher sound pressure levels should bedetermined as part of a fire risk assessment.

Great care should be taken when installingsystems in buildings such as single-familydwellings, where there is likely to be no fire risk assessment available. Such an assessmentshould be carried out in close consultation with the occupants, building control or theperson responsible for the dwelling. It is not the installer’s responsibility to specify soundpressure levels outside those recommended by BS 5839-6. However, you should be ableto draw the attention of the interested persons to the existence of this particular risk.

Use of manual call points

Manual call points should be provided in verylarge single-family dwellings or studentaccommodation. This will also generally apply tohouses with four storeys or more, multi-storeymansions, country houses and houses ofmultiple occupation (HMO).

It would be appropriate to consider the use ofmanual call points in all Grade A systems.

12. Zoning of Systems

Zoning is generally restricted to Grades A, B, and C systems. These are systems which willhave a control and indicating panel.

In most dwellings the zonal configuration wouldbe on a floor-by-floor basis. However, in largerHMOs there will probably be a complex zoneconfiguration and even a cause and effectmatrix. In these buildings addressable systemswould be appropriate.

• For Grade A systems in HMOs there should bea means of identifying the dwelling unitwhere the fire signal originated. This couldbe addressable text or a remote indicatoroutside each flat. The panel should becompliant with EN 54.

• For Grade B systems each floor is generallytreated as a zone. This does not need to bean EN 54 panel, although it may becheaper to use a standard small EN 54panel than to build one with the lesserfacilities allowable in this Grade of system.

• Grade C systems do not normally need to bedivided into zones for fire.

Smoke Alarm unit with integral85dB(A) sounder

EN 54 Addressable or Zoned fire alarmpanel

Basic fire alarm panel

Burglar or social alarm panel whichsupports 12 V smoke alarms

Fire Warning Sounder up to 110 dB (A)

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13. Wiring and Installation

The wiring of fire alarm and detection systems is carried out in accordance with BS5839Parts 1 and 6, which reference compliance with BS 7671 Requirements for ElectricalInstallations (IEE Wiring Regulations Seventeenth Edition).

• Grade A systems recommend the use of fire-resistant cables

• Grade B systems recommend the use of fire-resistant cables

• Grade C systems recommend that cable should be suitable for the current and voltageof the circuits concerned

• Grades D and E cables used may comprise of any cable suitable for domestic wiring

• Grade F cables used to interconnect the battery powered smoke alarms may be anytype of cable suitable for the current and voltage concerned

14. Maintenance and Servicing

System maintenance is critical in the performance of the system over its lifetime. Thesystem users should be encouraged to have their systems maintained at the appropriateintervals by a competent person.

• To comply with BS 5839-6 recommendation, BS 5839-1 based Grade A systemsshould be inspected at periods not exceeding six months

• Grades B and C systems should be inspected at periods not exceeding six months

• Grades D, E and F systems should be tested and cleaned in accordance with themanufacturer’s instructions

• Weekly sound checks by the user

• System servicing should be carried out by an organisation that can provide 24-hourservice availability and by competent service and maintenance personnel. FSAmembers are able provide this level of service.

Fire-Resistant Clips in Plastic TrunkingGrades A & B Systems

Fire-Resistant Cable ClipGrades A & B Systems

Remote Control OptionalGrade D & E System

Sealing of holes where cables passthrough the fabric of the building

Installation and maintenanceof wireless systems

Hard wiring of smoke alarms

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15. System Certification

Upon completion of a system, the appropriate certificates should be completed and signedby a competent person.

1) Grade A system (BS 5839-1/6)

a) BS 5839-6 Design certificate

b) BS 5839-6 Installation certificate (plus a BS 7671 Electrical Installation Certificate to support the registration for a Part P Certificate)

c) BS 5839-6 Commissioning certificate

d) BS 5839-6 Acceptance certificate

2) Grades B, C, D, E and F systems (BS 5839-6)

a) BS 5839-6 single certificate should be completed for all the above types of system (and should include a BS 7671 Electrical Installation Certificate or a Minor Electrical Installation Works Certificate to support the reporting procedure for a Part P Certificate)

16. Example Certificates(these can be downloaded free of charge from the ECA website www.eca.co.uk/common/pdf/menu.asp)

BS 5839 Grade A Certificates: Design, Installation, Commissioning and Acceptance

Important Note:

Fire Detection and Alarm Systems in dwellings come under Part P of the BuildingRegulations. This relates in particular to systems which require a dedicated mainssupply or where a device is installed in a special location, such as a kitchen. Thismeans that all Grades D and E - LD1 and LD2 category systems must be reportedunder Part P. Grades A, B and C systems must also be reported under Part P,since each of these systems requires a dedicated 230Volt mains supply.

Grades D and E - LD3 category systems do not need to be reported under Part P,where the mains supply is taken from a local lighting circuit. However, a BS 7671Minor Electrical Installation Works Certificate will be required, in addition to theBS 5839-6 Installation Certificate.

In the event that a dedicated mains supply is provided for Grades D and E - LD3category systems, then a BS 7671 Electrical Installation Certificate is required inaddition to a BS 5839-6 Installation Certificate and the system must be reportedunder Part P.

It should be clearly understood that a Competent Person who has been assessedby an approved Part P certification scheme must carry out any electrical workassociated with Part P.

Installation Certificate Commissioning Certificate

Design Certificate Page 1 Design Certificate Page 2

Required for Part P of the BuildingRegulations

Required for Part P for mains suppliestaken from an existing lighting circuit wherethere is a head detector in the kitchen

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*Companies’ logos may be used on the certificates, depending on the member’s requirements

17. Documentation

The installer is required to provide documented information to the interested partiesrelating to the maintenance and operation of the system which has been installed. This, inthe case of small systems D, E and F, may be as little as the manufacturer’s instructions.

18. References

The following reference documents are indispensable for the application of this document.For dated references, only the reference cited applies. For undated references, the latestedition of the document (including any amendments) applies.

BS 476 (relevant parts) Fire tests on building materials and structures.

BS 3955:1986 Specification for electrical controls for household and similargeneral purposes.

BS 5446-1:2000 Fire detection and fire alarm devices for dwellings - Part 1:Specification for smoke alarms.

BS 5446-2 Fire detection and fire alarm devices for dwellings - Part 2:Specification for heat alarms.

BS 5446-3 Fire detection and fire alarm devices for dwellings - Part 3:Specification for smoke alarms for deaf and hard of hearingpeople.

BS 5839-1:2002 Fire detection and fire alarm systems for buildings - Part 1: Code of+A2:2008 practice for system design, installation, commissioning and

maintenance.

BS 5979 Code of practice for remote centres receiving signals from securitysystems.

BS 7671 Requirements for electrical installations - IEE Wiring Regulations -Seventeenth edition.

BS EN 54-2 Fire detection and fire alarm systems - Part 2: Control andindicating equipment.

BS EN 54-3 Fire detection and fire alarm systems - Part 3: Fire alarm devices -Sounders.

BE EN 54-4 Fire detection and fire alarm systems - Part 4: Power supplyequipment.

BS EN 54-5 Fire detection and fire alarm systems - Part 5: Heat detectors -Point detectors.

BS 9999:2008 Fire Safety in the Design, Management and Use of Buildings.

BS 7671 Electrical Installation Certificate

Acceptance Certificate Completion Certificate (Single Certificate)For Grades B, C, D, E, and F systems

BS 7671 Minor Electrical InstallationWorks Certificate

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BS EN 54-7 Fire detection and fire alarm systems - Part 7: Smoke detectors -Point detectors using scattered light, transmitted light or ionization.

BS EN 54-11 Fire detection and fire alarm systems - Part 11: Manual call points.

BS EN 54-12 Fire detection and fire alarm systems - Part 12: Smoke detectors -Optical beam detectors.

BS EN ISO 13943 Fire safety - Vocabulary.

LPS 1265: Issue 1.0 Requirements and testing procedures for the LPCB approval andlisting of carbon monoxide fire detectors using electrochemical cells.Garston: Building Research Establishment, 2004.

LACORS Guide 2008 Local Authorities Coordinators of Regulatory Services - Housing Act2000 and Fire Safety Order 2005 - National Guidance on FireSafety Standards in Existing Residential Accommodation.

FSO Guidance Doc. Fire Risk Assessment - Sleeping Accommodation.

19. FSA Training Courses

Accredited training courses for the design, commissioning, installation and maintenance offire detection and alarm systems are available from the FSA on 0207 313 4888 from itsEducation and Training Department.

Course details on application:

Course T19-004 - Design, Installation, Commissioning and Maintenance of Fire Detectionand Alarm Systems in Dwellings

20. Frequently Asked Questions

Q Is BS 5839-6 a legal document and am I forced by law to implement its recommendations?

A Firstly, BS 5839-6 is only a Code of Practice and on its own it has no legal standing.BS 5839-6 is one way of complying with the Building Regulations and to some extentit is accepted as the best way to achieve compliance. If a project specification calls forBS 5839-6 and a contract is placed for the work to be carried out to this standard,BS 5839-6 becomes enshrined in the contract and therefore becomes a legalrequirement under contract law.

Q Battery-powered detectors - can they be used in new and materially altered buildings?

A No, these are listed as Grade F systems in BS 5839-6. They are there in order torecognise the existence of these units for use by owner-occupiers of existing single-storey dwellings. There are warning provisos regarding the use of Grade F systems.

Q I am rewiring two houses one of which has a number of flats. Both have battery-only smoke alarms at the top of the stairs. Do I have to add additional units,supply them from the mains and link them together?

A To answer the question we need to deal with these as separate functional buildingsalthough they belong to the same person. One is the single-family dwelling of theowner of both dwellings and the other is a small two-floor rented HMO containingfour flats. With the single-family dwelling it is the occupier who will dictate thesystem grade or category of any rewired smoke alarm system. He has no legalobligation to have any form of smoke alarm in his dwelling but may wish topurchase an upgrade if only for his own sense of safety. Since this is an existinghouse a BS 5839-6 Grade F LD3 system would be acceptable. Please refer to thesection on Grades and Categories relating to Grade F LD3 systems. Where thestructural fire precautions are of a lower standard a Grade D LD2 system should berecommended. Remember, all decisions on what is to be installed are theoccupier’s.

In considering the two-storey house, HMO, with the four rented flats, this will besubject to a fire risk assessment provided by the landlord (the responsible person).The landlord has a legal duty of care to his tenants to ensure that they are kept safefrom harm due to the effects of fire within the rented property. In this existingbuilding the minimum would be subject to the outcome of the fire risk assessment,a Grade D LD3 system in the common areas, and if there are two or more rooms inthe flats a Grade D LD3 system in each flat. In existing HMOs where the structuralfire precautions are of a lower standard, the fire risk assessment should call forGrade D LD2 systems in both the communal areas and each flat. In the event thatthe flats have only one room, then there is no requirement in BS 5839-6 for asmoke alarm. However, it would be prudent to recommend to the landlord, that as aminimum, a battery or mains-powered smoke alarm should be installed in the roomto cover the sleeping risk. These do not need to be connected to the communalsystem.

Q BS 5839-1 recommends that detectors should not be sited less than 500mm fromwalls and beams and BS 5839-6 recommends that they should not be sited lessthan 300mm. Which one is right?

A BS 5839-1 was written before BS 5839-6 when it was realised that where somecorridors were less than 1m wide, 500mm from the wall would not be workable.Since BS 5839 permits detectors to be mounted on the wall, the 500mm quoted inBS 5839 is irrelevant. 300mm is acceptable.

Q Do Grades C, D and E systems need to be wired in fire-resistant cable?

A These grades of system need only to be provided with general cables, which aresuitable for the voltage and current being used by the system. Only Grades A and Brequire fire-resistant cables.

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Q BS 5839-1 says that for reasons of electrical safety, the mains supply to all parts ofthe fire alarm system should be supplied via an isolating protective device (such as acircuit-breaker). BS 5839-6 on the other hand, says that the circuit serving the firedetection and alarm system should preferably not be protected by any residualcurrent device (RCD). Which is right?

A Dedicated circuits are required for Grades A, B and C systems, so the use of an RCDdoes not present a problem. With the introduction of the 17th edition of BS 7671 -IEE Wiring Regulations, all new dwellings will be required to have RCD units.

Where Grades D and E smoke alarms are supplied from a frequently used lightingcircuit, it is likely that by default, this will be provided with an RCD unit. In certaincircumstances, there is a risk that the unit could trip out. BS 5839-6 states that firealarm and detection systems should preferably not be protected by an RCD. However,this recommendation would be satisfied if a time delayed 100mA RCD served the entireelectrical installation including the smoke alarms. BS 7671 17th Edition will changethis. Now new and altered domestic installations, which include fire systems, will berequired to have 30mA RCD protection throughout. Careful consideration needs to begiven to the possibility of accidental trip-out incidents when considering using thelighting circuits as the source of the mains supply. The use of a separate dedicatedcircuit is a means of ensuring that the risk of trip-out due to other equipment is reduced.

Q Which Grades of system have to be wired in fire-resistant cable?

A Only systems which are covered by BS 5839-1. These are Grades A and B systems.

Q Do the supporting clips and fixings have to be fire-resistant?

A Fire-resistant clips and fixings are only required for Grades A and B systems. All othersystems, Grades C, D and F, do not require fire-resistant cables, clips or fixings.Equipment, cables and clips should under no circumstances be simply stuck to thesurfaces on which they are mounted or run.

Q Does a dwelling come under the Fire Safety Order (FSO)?

A The only dwellings that are covered by the Fire Safety Order 2005 are Houses ofMultiple Occupation (HMO). These are houses that are occupied by persons who donot form a single household.

Q Which room is the principal room of habitation?

A Any room in a dwelling other than a kitchen, utility room, bathroom, dressing room orWC. It is normally the most frequently used room for general daytime living.

Q Which grades of system require the circuits to be monitored?

A Only Grades A, B and C systems, which are those that use a control and indicationpanel, can have their circuits monitored.

Q Can I use a lighting circuit to power a Grade D system?

A Yes, but you need to be aware that a fluorescent light can affect the smoke alarmwhen the light is switched on and off. Reference should be made to the manufacturer’srecommendations when using lighting circuits to power smoke alarms.

Q When should remote transmission of signals be considered?

A Where occupants are at risk due to impaired mobility, or where occupants have speechimpairment, which would stop them communicating by phone. Insurers will normallyrequire remote transmission connections for category P systems.

Q Do I need smoke detectors in bedrooms?

A BS 5839-6 does not require this. It is therefore a question for the occupiers to assesstheir fire risk and to judge if they need additional protection over and above what isrecommended in the standard.

Q I have a loft conversion where Building Control requires a smoke detector in theextension. The smoke alarms on the ground and first floors are not interlinked. Dowe need to interlink all the smoke alarms?

A It is important that smoke alarms are linked together so that, in a fire situation, all theintegral sounders and warning devices operate at the same time.

Q Do we need to install a heat detector in an integral garage?

A Integrated garages should be fire compartments in their own right. However, a fire riskassessment would normally recommend that, since the category of system is an LD1or LD2, then a heat detector should be installed in the garage, particularly if there isan internal door opening into the dwelling. If the recommended category is defined asLD3 and there is no internal door then the installation of a heat detector in the garagewould not normally be required. However, the client should be consulted regarding thewisdom of installing a heat detector in these areas.

While every care has been taken to ensure the accuracy of information containedin this booklet, neither the author nor the publisher can accept any liability forany inaccuracies or omissions from the information provided or any loss ordamage arising from or related to its use.

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