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BSI 24/30473259 DC 2024

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BS 5839-1 Fire detection and fire alarm systems for buildings – Design, installation, commissioning and maintenance of systems in non-domestic premises. Code of practice

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BSI 2024 170
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10 Section 1: General
Introduction
12 1 Scope
13 2 Normative references
15 3 Terms and definitions
3.1 access room
3.2 addressable system
3.3 alarm receiving centre (ARC)
3.4 alarm zone
3.5 area of low fire risk
3.6 aspirating smoke detection system
3.7 audibility
3.8 automatic fire detection and fire alarm system
3.9 circuit
3.10 circulation area
3.11 coincidence
16 3.12 combustion gas detector
3.13 commissioning
3.14 competent person
3.15 control and indicating equipment (CIE)
3.16 critical signal path
3.17 designer
3.18 detection zone
17 3.19 dual path alarm transmission system
3.20 false alarm
3.21 fire alarm device
3.22 fire alarm sounder
3.23 fire detection and fire alarm system
3.24 fire detector
3.25 fire engineering solution
3.26 fire hazard level
3.27 fire resistance
3.28 fire-resisting
18 3.29 fire risk
3.30 fire signal
3.31 flame detector
3.32 heat detector
3.33 inner room
3.34 installation
3.35 installer
3.36 lantern-light
3.37 line detector
3.38 maintenance
3.39 manual call point
3.40 manual system
3.41 maximum alarm load
3.42 mimic diagram
3.43 minimum static response temperature
19 3.44 multi-sensor fire detector
3.45 networked system
3.46 normal supply
3.47 phased evacuation
3.48 point detector
3.49 pre-alarm warning
3.50 premises management
3.51 protection
3.52 purchaser
3.53 radio-linked system
3.54 rate of rise heat detector
3.55 repair
3.56 search distance
3.57 sector
20 3.58 servicing
3.59 short circuit isolator
3.60 smoke
3.61 smoke detector
3.62 soak period
3.63 staff alarm
3.64 staged fire alarm
3.65 standby supply
3.66 storey
3.67 storey exit
3.68 time-related system
21 3.69 unwanted fire alarm signal
3.70 user
3.71 visual alarm device
3.72 visual display unit
3.73 voice alarm system
3.74 voice sounder
3.75 zone plan
4 Categories of system
22 4.1 If the category of system is stipulated in the requirements imposed by an enforcing authority, by property insurers or by the purchaser of the system, that category should be used.
23 4.2 If the designer has not been informed as to the category of system required, they should make a proposal based on the fire strategy together with professional knowledge and experience, and should discuss this with the purchaser (see 5.4).
4.3 Category L1, L2, L3 and L4 systems should also satisfy the recommendations of this part of BS 5839 for a Category M system.
4.4 Category P1/M, P2/M and L5/M systems should satisfy the recommendations of this part of BS 5839 for a Category M system together with those for a Category P1, P2 or L5 system, respectively.
4.5 Category X/Y systems (e.g. L2/P2 or L3/P2) should satisfy the recommendations of this part of BS 5839 for for both the “X” system (e.g. L2 or L3) and the “Y” system (e.g. P2).
4.6 Where a Category P system is to be installed, it should be determined whether there would be benefit in providing manual call points. If this is the case then a Category P/M system should be installed.
5 Exchange of information and definition of responsibilities
5.1 Consultations should take prior to the design stage between the following relevant interested parties:
24 5.2 Consultations should take place at the design stage between the following relevant interested parties:
5.3 Consultations should take place at the installation stage between the following relevant interested parties:
5.4 If the designer has made a proposal for the category of system (see 4.2), this should be discussed and agreed with the purchaser.
5.5 The designer of the system should ascertain from the user/purchaser whether the fire detection and fire alarm system is to incorporate a visual alarm device.
5.6 Before an order is placed for the system, the responsibility for each of the following stages should be clearly defined and documented:
5.7 Before an order is placed for the system, the responsibility for the provision of a zone plan (see 22.2.5) should be clearly defined, agreed and documented.
5.8 Where a fire detection and fire alarm system is to be integrated with a voice alarm system, one organization should take responsibility for the interface connections and all necessary communications between the fire detection and fire alarm system…
5.9 Where a fire detection and fire alarm system is to be interfaced with another system or facility (such as a fire extinguishing system, smoke control system or lift grounding facility) that is the responsibility of an organization other than the in…
25 6 Variations from the recommendations of this document
6.1 Variations from this part of BS 5839 incorporated within a specification or design proposal should be clearly identified so that they are obvious to any party from whom approval of the specification or design proposal might be sought, such as the …
6.2 Variations from this part of BS 5839 identified or proposed during installation or commissioning, but not clearly identified in the documented design, should be documented (other than in the case of errors or “snags” for which rectification is pro…
26 6.3 All variations should be agreed amongst the interested parties (see Clause 5).
6.4 All variations should be listed in the relevant system certificate (see Clause 39).
6.5 All variations should be clearly recorded in the logbook so that they are readily available for future reference by maintenance companies and any other interested parties.
6.6 Certain departures from the recommendations of this part of BS 5839 are likely to be so detrimental to the safety of life that they should not be regarded as acceptable variations. For example, the following departures should not be regarded as ac…
27 Section 2: Design considerations
7 Relationship between system category and protected areas
28 7.1 System documentation, including any specification, design proposal, submission to enforcing authorities and the certificate issued by the designers (see Clause 39), should clearly identify the system category as well as, where appropriate, the are…
7.3 The description of the system should include information on the areas of the building that are to be protected for a Category L2, L5 or P2 system.
7.4 Any specification or proposal for a Category L2, L5 or P2 system should clearly identify the rooms or areas that are to be protected by automatic fire detectors.
29 7.5 In Category L1, L3 and L4 systems, smoke detectors, multi-sensor detectors conforming to the fire sensitivity requirements of BS EN 54-7 or a mixture of smoke and combustion gas detectors, should be provided in:
7.6 Multi-sensor detectors used in Category L1, L3 and L4 systems (see 7.5) should have the smoke sensor enabled to meet the fire sensitivity requirements of BS EN 54-7.
7.7 In Category L3 systems, heat, smoke, combustion gas or multi-sensor detectors should be installed on the accommodation side of any door that opens onto the escape routes described in 7.5, except for rooms opening onto corridors of less than 4 m in…
7.8 In a Category L2 system, the rooms or areas protected should meet the recommendations in 7.5 and 7.7 for a Category L3 system, but, in addition, automatic fire detectors should be installed in rooms in which the fire risk (see 3.29) is high enough…
7.9 In a Category L1 or P1 system, automatic fire detectors should be installed in all rooms and areas of the building, except that the following rooms or areas need not be protected if they are of low fire risk (see 3.29):
7.10 In a Category L1 system in a room in which there is a need for automatic activation to protect the occupants of the room in the event of a fire in that room (e.g. if they are asleep), smoke detectors, combustion gas detectors or multi-sensor dete…
7.11 In a Category P2 system, the rooms or areas to be protected by automatic fire detectors should be clearly identified in the specification or proposal. There should be physical barriers between protected and unprotected areas to limit the spread o…
30 7.12 Where occupants of a building are likely to need assistance from staff to evacuate the building (e.g. in residential care premises and hospitals), the fire detection and fire alarm system should be addressable if the building has facilities for m…
8 Actuation of other fire protection systems or safety facilities
8.1 The recommendations given in 8.2 to 8.4 should be met in the case of systems intended to actuate other fire protection systems or safety facilities (e.g. by triggering an automatic fire extinguishing system, closing fire-resisting doors, shutting …
8.2 The fire detection and fire alarm system should meet the recommendations in any applicable part of BS 7273.
8.3 If is anticipated that operation of the fire detection and fire alarm system during routine testing could have an undesirable effect on other systems or equipment, means should be provided for disabling the automatic actuation of the system or equ…
8.4 Other systems, where reasonably practicable, should be prevented from drawing power from the fire detection and fire alarm system. Where it is necessary for the fire detection and fire alarm system to provide power to operate other equipment or sy…
9 Systems in explosive gas or dust atmospheres
9.1 Any system (or part of a system) protecting an area, or with cables passing through an area, in which there might be an explosive gas, vapour or mist atmosphere should conform to BS EN 60079-14.
9.2 Any system (or part of a system) protecting an area, or with cables passing through an area, in which there might be an explosive dust atmosphere should conform to BS EN 60079-17.
31 10 System components
10.1 Manual call points should conform to BS EN 54-11:2001 for Type A (single action) manual call points.
10.2 Point heat detectors should conform to BS EN 54-5:2017+A1 for Class A1 or A2 detectors, unless the foreseeable maximum ambient temperature in the protected area is 40 C or above, in which case a Class B-G detector should be used as appropriate (…
10.3 Point smoke detectors should conform to BS EN 54-7.
10.4 Flame detectors should conform to BS EN 54-10.
10.5 Optical beam smoke detectors should conform to BS EN 54-12.
10.6 Aspirating smoke detectors should conform to BS EN 54-20:2006.
10.7 Components and systems using radio links should conform to BS EN 54-25.
10.8 Multi-sensor, optical and heat detectors should conform to either:
10.9 Multi-sensor, carbon monoxide and heat detectors should conform to BS ISO 7240-8 or BS EN 54-30.
10.10 Multi-sensor detectors combining smoke, carbon monoxide and heat sensors should conform to BS EN 54-31.
10.11 If there is a facility in a multi-sensor detector to disable sensors leaving a single active sensor, the multi-sensor detector should also meet the performance requirements of the appropriate part of BS EN 54 relevant to that single active sensor.
10.12 Carbon monoxide fire detectors should conform to BS EN 54-26.
32 10.13 CIE should conform to BS EN 54-2.
10.14 Audible fire alarm devices should conform to BS EN 54-3.
10.15 Visual alarm devices should conform to BS EN 54-23.
10.16 Power supply equipment should conform to BS EN 54-4.
10.17 Cables should meet the recommendations in Clause 25.
10.18 Those functions of the system that are recommended in this part of BS 5839, for which the storage of programs and data are necessary to control the fire detection and fire alarm system, should conform to the additional design requirements for so…
10.19 Where a computer or similar IT equipment is used as a user interface, e.g. in networked systems, it should be treated as a supplementary interface and there should be CIE conforming to BS EN 54-2 mounted nearby.
10.20 Radiopaging transmitters and receivers should conform to the relevant British or harmonized European Standards.
10.21 Alarm transmission and fault warning routing equipment should conform to the product requirements specified in BS EN 54-21.
11 Monitoring, integrity and reliability of circuits external to control equipment
33 11.1 Fault monitoring
11.1.1 A fault indication should be given at the CIE within 100 s of the occurrence of any of the following conditions:
11.1.2 A fault indication should be given, within the times indicated below, in the event of any of the following:
11.1.3 Visual indications of the faults identified in 11.1.1c) and 11.1.1i) should continue to be given at the CIE during a fire alarm condition.
11.1.4 Where any standby power supply comprises a number of batteries connected in parallel, a fault indication should be given in the event of disconnection of any one battery (within 15 min of occurrence).
34 11.1.5 If the system incorporates a separate voice alarm system or fire warning system for people who are Deaf or have a hearing impairment, any short circuit or disconnection of the communicating link between the fire detection and fire alarm system …
11.1.6 If the system is used to actuate other fire protection systems or safety facilities (see Clause 8), the recommendations given in the relevant part of the BS 7273 series, BS 7346-8, or other code of practice applicable to the specific system, sh…
11.1.7 Where tactile fire alarm devices provided for people who are Deaf or have a hearing impairment are installed, the system should conform to Annex C and should indicate the failure to receive a monitoring signal correctly (see 17.1.2).
11.2 System integrity
11.2.1 A fault on one circuit containing manual call points, fire detectors or fire alarm devices, or a combination of them, should not affect any other circuit.
11.2.2 A single short circuit or open circuit fault on an automatic fire detector circuit should not disable protection:
11.2.3 Two simultaneous faults on a manual call point or fire detector circuit should not disable protection within an area greater than 10 000 m2.
11.2.4 For software controlled CIE that has more than 512 detectors and/or manual call points connected, the manufacturer’s instructions should be followed with regard to the means by which conformity with BS EN 54-2 is to be achieved.
11.2.5 Where detectors are designed to be detachable from their bases for the purpose of routine maintenance of the system:
11.2.6 Any facility specifically provided for deliberate disablement of manual call point or detector circuits should be such that it is possible to disable protection throughout one zone of the system without disabling protection in other zones. Use …
11.2.7 Removal of any manual call point or detector from its circuit should not affect the ability of any fire alarm device to respond to an alarm signal, other than in the case of fire alarm devices and detectors that are combined at a single fixing …
11.2.8 Fire alarm devices should be capable of being removed only by the use of a special tool.
35 11.2.9 In the event of a single open circuit or short circuit fault on any circuit that serves fire alarm sounders, at least one single fire alarm sounder, normally located in the vicinity of the CIE, should still sound correctly if a fire alarm condi…
11.2.10 In buildings designed to accommodate the general public in large numbers (e.g. transport terminals, shopping centres, places of public entertainment, department stores and leisure centres), at least two sounder circuits should be provided in e…
11.2.11 The recommendation in 11.2.10 should be achieved either:
11.2.12 Where two or more independent sounder circuits are required to maintain system integrity [see 11.2.11a)], the circuits should not be contained within a common cable sheath. For example, two circuits intended to satisfy the recommendations in 1…
11.2.13 If the CIE is supplied with power from power supply equipment contained in a separate enclosure, the cables between the equipment should be duplicated such that a single open or short circuit in the connections does not completely remove power…
11.2.14 Where a power supply unit or a standby battery(ies) is housed in a separate enclosure from the CIE, any cable between that enclosure and the CIE should be protected against overcurrent in accordance with BS 7671:2018+A2.
37 12 Detection zones
38 12.1 All detection zones
12.2 Detection zones that contain only manual call points
12.3 Detection zones that contain non-addressable automatic fire detectors
39 12.4 Detection zones containing addressable automatic fire detectors
40 12.5 Remote indication of detector operation
12.5.1 Any remote indicators should be clearly labelled to indicate their function. They should be sited and/or labelled in such a way as to assist in determining the location of the detectors that they serve.
12.5.2 Any cable between a detector and a remote indicator that is needed for conformity to this part of BS 5839 should meet the recommendations in Clause 25.
13 Alarm zones
13.1 The boundaries of every alarm zone (other than external walls) should comprise fire-resisting construction.
13.2 Signals between alarm zones should not overlap.
13.3 A common signal should be used throughout all alarm zones to convey the need for evacuation, and a (different) common signal should be used throughout all alarm zones for any alert signal that can be given by the system.
13.4 The boundaries of alarm zones should coincide with the boundaries of the relevant detection zones (see Figure 4). A detection zone should not incorporate more than one alarm zone.
41 14 Communication with the fire and rescue service
42 14.1 The user should be informed that there need to be suitable arrangements for summoning the fire and rescue service when the fire detection and fire alarm system operates, and that these arrangements need to be such as to minimize the risk to any p…
43 14.2 The user should be informed that in occupied buildings, the primary means of summoning the fire and rescue service should always comprise a call to the fire and rescue service by occupants, using the public emergency call system.
14.3 Systems that automatically transmit a pre-recorded message direct to the fire and rescue service, via the public emergency call system, should not be used.
14.4 In any area specifically designated as that from which the fire and rescue service is to be summoned in the event of fire, the fire alarm signal should not be so loud as to interfere with telephone speech.
14.5 The designer should determine from the purchaser or user whether automatic means of transmission of alarm signals to an ARC is required by the user.
14.6 If the early summoning of the fire and rescue service is deemed to be critical to the safety of occupants (e.g. on the basis of a fire risk assessment), facilities should be provided for automatic transmission of alarm signals to an ARC, unless t…
14.7 In residential care premises, facilities should be provided for automatic transmission of alarm signals to an ARC.
14.8 Except in the case of continuously occupied premises, Category P systems should incorporate a means for automatic transmission of fire signals to an ARC.
14.9 In non-domestic premises in multiple occupation, Category L systems should incorporate an automatic means for transmission of alarm signals to an ARC, unless there are arrangements in place for summoning the fire and rescue service by occupants o…
14.10 Where facilities for automatic transmission of fire alarm signals to an ARC are arranged, the ARC should be provided with all relevant information about the premises (e.g. whether they incorporate sleeping accommodation). Where practicable, the …
14.11 Any ARC to which fire alarm signals are relayed should conform to BS EN 50518 and BS 9518 in respect of the processing of alarm signals, and should have in place an agreement with the appropriate fire and rescue service to pass on fire signals f…
14.12 If a Category L or Category P system incorporates facilities for automatic transmission of fire signals to an ARC, any telephone switch room or frame room on which automatic transmission depends should be protected by automatic fire detection or…
44 14.13 Automatic transmission of alarm signals should not be prevented by the act of silencing fire alarm sounders and should not depend on the state of any silencing switch.
14.14 Where an alarm transmission device is mounted in an enclosure separate from that of the fire alarm CIE, the connection from the CIE to the alarm transmission device should be monitored and comprise cables of standard fire resistance. The CIE sho…
14.15 Mains power supplies for any facility used for the transmission of fire alarm signals to an ARC should conform to Clause 24, with the exception of mains power supplies for an intruder alarm system, which should conform to 14.15.
14.16 Where fire alarm signals are routed via the routing equipment of an intruder alarm system, the standby power supplies for the routing equipment should conform to 25.4. The power supply unit should conform to either BS EN 54-4 or BS EN 50131-6:20…
14.17 If it is intended for the CIE to signal a fault from the fire alarm system to an ARC, the CIE should have a suitably monitored means of interfacing with the relevant fault routing equipment.
14.18 Faults in either the alarm transmission equipment or in the alarm transmission path should be displayed on the CIE.
14.19 Where the alarm transmission path relies upon a physical TCP/IP or similar data connection, the following recommendations should be met.
45 14.20 Where the functionality is provided for automatic transmission of alarm signals to an ARC, there should be a label on or adjacent to the CIE to avoid a false activation that could summon the fire and rescue service.
15 Audible alarm signals
46 15.1 Category M and L systems (other than in hospitals and residential care premises)
15.1.1 The sound pressure level of alarm signals should, when measured with all doors shut, be:
15.1.2 Where the sound pressure level of background noise is greater than 60 dB(A), the sound pressure level of the fire alarm signal should be 5 dB(A) above the sound pressure level of the background noise.
47 15.1.3 The fundamental frequency(ies) produced by fire alarm sounders should lie in the range of 500 Hz to 1 000 Hz, unless the frequency of background noise is such as to mask these frequencies, in which case the use of sounder frequencies outside th…
15.1.4 All fire alarm sounders within a building should have similar sound characteristics, unless particular conditions, such as an area of high background noise, make this impracticable. The sounders should be distinctive in sound from the sounds of…
15.1.5 In premises designed for public entertainment, retail and similar premises, in which the sound pressure level of music is likely to be greater than 80 dB(A), the music should be muted automatically when a fire alarm signal is given.
15.1.6 The fire and rescue service should be consulted to determine whether there is a need to provide external sounders and/or visual alarm devices. Where external sounder(s) and/or visual alarm device(s) are provided, they should be clearly marked w…
15.1.7 A facility should be provided to enable silencing of alarm signals. The operation of this facility should:
15.1.8 Alarm signals should not silence automatically (i.e. after a predetermined time period), other than in the following circumstances.
48 15.1.9 The system should incorporate at least two fire alarm sounders. At least one sounder should be provided in each fire compartment.
15.1.10 If audible alarms comprise speech messages generated by a voice alarm system or voice sounder (see 3.74), the relevant recommendations of BS 5839-8 should be followed in respect of message content, sound pressure levels and speech intelligibil…
15.1.11 Fire alarm evacuation tones should not be used for purposes other than warning of fire, except where:
49 15.2 Category P systems
15.3 Hospitals and residential care premises
15.3.1 Audible alarms in hospitals should conform to Department of Health publications HTM 05-03 Part B [N1] (in England and Wales) or SHTM 82 [N2] (in Scotland).
15.3.2 Audible alarms in residential care premises should meet the relevant recommendations in 15.1.1.
16 Visual alarm signals
50 16.1 Visual alarm signals should be provided in areas where ambient noise levels exceed 90 dB(A) and in other areas where hearing protection is likely to be used under normal circumstances.
16.2 Visual alarm devices should be sufficient in number and distribution to be readily visible from all normally accessible locations, throughout the area in which they are provided, under normal ambient lighting levels.
16.3 The visual alarm signal should flash at a rate within the range of 30 to 120 flashes per minute.
16.4 The visual alarm signal should be clearly distinguishable from any other visual signal used in the premises. Visual alarm signals should be white or red, or both white and red, in colour, unless use of another colour is necessary to distinguish t…
16.5 The intensity of output of visual alarm devices should be sufficient to attract attention, but not so high as to cause difficulty with vision due to glare.
16.6 Visual alarms should be securely fixed in accordance with the mounting position (ceiling or wall) and orientation specified by the manufacturer. The mounting height should be not less than 2.1 m.
17 Fire alarm warnings for people who are Deaf or have a hearing impairment
51 17.1 General
17.1.1 Visual alarm signals provided for people who are Deaf or have a hearing impairment should conform to Clause 16. The visual alarm devices should be regarded as fire alarm devices for the purpose of this part of BS 5839 and, for example, circuits…
17.1.2 Fixed or moveable tactile devices should be regarded as fire alarm devices for the purpose of this part of BS 5839. For example, circuits serving the devices should be monitored and flexible cables attached to devices should be protected agains…
52 17.1.3 Where a tactile device is intended to rouse people from sleep, the intensity and frequency of the alarm signal should conform to BS 5446-3:2015, 6.4 and 6.5 for vibrating alerters used as vibrating pads.
17.1.4 Where tactile devices are provided, control and transmission equipment should meet the recommendations given in Annex C.
17.2 Portable alarm devices
17.2.1 Portable alarm devices to supplement the primary means of giving an alarm of fire, if activated by radio signals, should meet the recommendations given in 17.2.2 to 17.2.12.
17.2.2 The alarm should be given at the portable alarm device within 5 s of the generation of the alarm signal at the fire detection and fire alarm CIE.
17.2.3 The alarm signal emitted by the portable alarm device should continue for at least 60 s after reception of every alarm transmission or until it is acknowledged at the portable alarm device.
17.2.4 In a fire condition, the transmission equipment should either:
17.2.5 Where the portable alarm device is also used for other purposes (e.g. general paging), the recipient should, by means of the cadence pattern, be able to tell the difference between a signal of fire and a signal for other non-emergency purposes.
17.2.6 Where the portable alarm device is also used for other purposes (e.g. general paging), the fire signal should have priority over any other signal so that the recommendation in 17.2.2 is satisfied regardless of the occurrence of other system act…
17.2.7 A failure of the interconnection (e.g. radio transmission) between the transmission equipment and the portable alarm device should be identified at the portable alarm device by a visual and tactile signal within 5 min of the failure. The visual…
53 17.2.8 For portable alarm devices that are operated from a single power source (typically a battery), a low power source voltage should be identified at the portable alarm device by a visual and tactile signal. If the tactile signal is given continuou…
17.2.9 If a portable alarm device is fitted with an off switch, or a switch disabling the alarm signal, the design of the switch should be such as to avoid inadvertent operation.
17.2.10 All faults identified at the control equipment for the portable alarm system should result, in, at least, a common fault warning at the fire detection and fire alarm system CIE within 100 s of the fault being identified at the portable alarm c…
17.2.11 The portable alarm system should meet the recommendations in this part of BS 5839 for:
17.2.12 Vibratory devices should conform to BS 5446-3:2015, 6.5.2.
18 Staged fire alarms
54 18.1 Staged alarm systems for phased evacuation
18.2 Staff alarms
18.2.1 Staff alarms should be used only where staff, including any night staff, are sufficient in number and fully trained in the action they are to take in the event of fire.
18.2.2 In residential care premises, a staff alarm should not incorporate any delay in summoning of the fire and rescue service when the fire alarm system operates.
55 18.2.3 In other premises, if the fire and rescue service is not summoned immediately at the start of any investigation period associated with a staff alarm, they should be summoned immediately on expiry of this period, unless it has been determined th…
18.2.4 Staff alarms should normally be generated only in response to signals from automatic fire detectors, but not in response to signals from manual call points, heat detectors or sprinkler systems. If it is proposed to use a staff alarm as the init…
18.2.5 Staff alarm signals comprising visual fire alarm devices should conform to Clause 16.
18.2.6 In premises with a staff alarm system, there should be provision, throughout all areas of the building, for sounding an audible fire warning conforming to Clause 15. Facilities should be provided at the CIE, and at additional locations if appro…
18.2.7 A staff alarm signal should automatically change to an audible fire warning in at least the relevant alarm zone after a preset period, unless manual intervention to stop the associated timer occurs at the control equipment. The period for the s…
18.2.8 A staff alarm signal should automatically change to an audible fire warning in at least the relevant alarm zone if a second detector operates before the system is reset.
18.2.9 In buildings with a staff alarm, smoke detectors in access rooms that form the only means of escape from inner rooms should give an immediate local warning of fire to occupants of the inner rooms, unless there is adequate vision between the in…
56 18.3 Audible “Alert” signals
18.3.1 The audible alert signal should be intermittent (1 ±0.5) s on and (1 ±0.5) s off.
18.3.2 Signals from different fire alarm devices should be synchronized. Synchronization should be sufficient that the “Alert” signal cannot be confused with a continuous “Evacuate” signal.
18.3.3 Provision should be made for manually changing the “Alert” signal to the “Evacuation” signal in any area.
18.3.4 If provision is made for the “Alert” signal to cease automatically after 30 s, then, at periods not exceeding 3 min, the signal should be restored for a period of at least 10 s until it is manually silenced.
19 Manual call points
57 19.1 The method of operation of all manual call points in a system should be that of Type A as specified in BS EN 54-11:2001. The method of operation of all call points should be identical unless there is a specific reason for differentiation.
19.2 All manual call points should be fitted with a transparent protective cover, which is moved to gain access to the frangible element.
19.3 The delay between operation of a manual call point and the giving of an “Evacuate” signal in, at least, the alarm zone within which the call point is located should not exceed 3 s.
19.4 Manual call points should be located on escape routes and at all storey exits and all exits to open air that lead to an ultimate place of safety (whether or not the exits are specifically designated as fire exits). Manual call points located at s…
19.5 Distribution of manual call points should be such that no one need travel more than 45 m to reach the nearest manual call point, measured along the route that a person would follow taking into account the layout of walls, partitions and fittings….
19.6 Where specific equipment or activities result in a high fire hazard level (e.g. kitchens or cellulose paint spraying), a manual call point should be sited in close proximity.
58 19.7 In buildings with phased evacuation, a manual call point should be located at every designated exit from an alarm zone.
19.9 Where manual call points will be viewed from the side (e.g. in corridors), they should be surface-mounted or semi-recessed with the front face proud of the mounting surface by not less than 15 mm.
19.10 In public car parks, if an emergency voice communication system is used in lieu of manual call points, the system should conform to BS 5839-9. All outstations should be Type B outstations in accordance with BS 5839-9. The master station should b…
20 Types of fire detector and their selection
63 20.1 The type(s) of fire detector used in a system should protect occupants, property or both, as appropriate to the category of system, while minimizing the risk of false alarms as far as practicable (see Section 3). The detectors should be maintaina…
20.2 Heat detectors should not be used in:
20.3 Smoke detectors should not be used in:
64 20.4 In Category L systems, smoke detectors installed within corridors and stairways that form part of the means of escape should be of the optical type or a mixture of optical smoke and combustion gas detectors, unless the use of optical detectors wo…
20.5 In areas in which early detection of a smouldering fire is required, optical smoke detectors, optical beam smoke detectors, aspirating smoke detection systems, carbon monoxide fire detectors or suitable multi-sensor fire detectors should be used.
20.6 In areas in which early detection of a relatively fast and clean-burning flaming fire is required, one of the following should be used, with a) and b) being the preferred options:
20.7 Carbon monoxide fire detectors should be used only to protect any of the following areas:
20.8 Flame detectors should be used only in situations in which it is sufficient for the fire detection system to respond to flaming fires, but not fires that produce smoke without significant flame (e.g. smouldering fires). For flame detectors to be …
20.9 Ultraviolet flame detectors should not be used as the sole means of fire detection in areas within buildings in which a fire can produce significant quantities of smoke before flaming occurs.
20.10 When video fire detectors are used as the sole means of detection, the recommendations of the product manufacturer and/or suppliers in terms of detection performance and application limitations should be followed, and specialist knowledge should…
65 20.11 Where detection can be set to a number of different operating modes (e.g. a multi-sensor fire detection system with a number of different response characteristics), the designer should record the selection of the detector type and configuration….
21 Siting and spacing of automatic fire detectors
66 21.1 Provision of automatic fire detectors
21.1.1 Fire detectors should be provided in accordance with Clause 7.
21.1.2 In stairways, fire detectors should be sited at the top of the stairway and on each main landing.
67 21.1.4 If the system category is such that automatic fire detection should be provided in any area that contains a horizontal void of 800 mm or more in height, automatic fire detection should also be provided in the void. Voids less than 800 mm in hei…
21.1.5 If any lantern-light (see 3.36) within a protected area is 800 mm or more in depth, or is used for ventilation, a fire detector should be sited in the lantern-light.
21.2 Siting of heat, smoke and multi-sensor detectors
21.2.1 Under flat ceilings (see Note 1), the horizontal distance between any point in a protected area and the detector nearest to that point should not exceed the following values or those given in BS 7273-4, whichever are the lower (see Note 4):
21.2.2 If the protected area has a pitched ceiling, for detectors at or near the apex, the horizontal distances between any point in a protected area and the detector nearest to that point should not exceed the values recommended in 21.2.1 plus an inc…
68 21.2.3 In apex roofs, fire detectors should be sited at or near each apex (see also Note 1 to 21.2.1 and Note to 22.2.2). For roofs with a pitch deeper than 600 mm, fire detectors should be within the top 600 mm (see Figure 10) and increased coverage …
21.2.4 Other than within rooms in a Category L3 system (see 21.2.5), in voids (see 21.2.6) or where a horizontal ceiling comprises a series of small cells (see 21.2.12 and 21.2.13), fire detectors should be sited on ceilings, such that their sensitive…
21.2.5 Detectors within rooms that open onto escape routes in a Category L3 system should either be sited in accordance with 21.2.4 or be sited on a wall, close to any door that opens onto an escape route. Wall-mounted detectors should be sited such t…
21.2.6 In unventilated voids not greater than 1.5 m in depth, the sensing element of fire detectors should be sited within the top 10% of the void or the top 125 mm, whichever is the greater (see Figure 11). Voids greater than 1.5 m in depth should be…
21.2.7 Where practicable due to the layout of the ceiling, and with the exception of enclosed areas with no horizontal dimension greater than 1 m and detectors within rooms opening into escape routes in a Category L3 system, heat and smoke detectors s…
21.2.8 Where practicable due to the layout of the ceiling, structural beams, ductwork, light fittings or other isolated ceiling attachments not greater than 250 mm in depth create obstacles to the flow of smoke, detectors should not be mounted closer …
21.2.9 Where an area contains partitions or storage racks that reach within 300 mm of the ceiling, the partitions or storage racks should be treated as walls that extend to the ceiling (see Figure 13).
69 21.2.10 Ceiling obstructions, such as structural beams, deeper than 10% of the overall ceiling height should be treated as walls (see Figure 14). Within horizontal voids, beams or obstructions that are deeper than 10% of the overall depth of the void,…
21.2.11 Where obstructions are installed close to the ceiling, these obstructions should be treated as a wall if:
21.2.12 Where a horizontal ceiling comprises a series of small cells (a honeycomb ceiling), detector spacing and siting should be in accordance with Table 1, Figure 15 and Figure 16. The shortest dimension should be taken as the width of a cell.
21.2.13 Where there are a number of closely spaced structural beams (approximately 1 m or less from centre to centre), such as floor joists, the following recommendations should be met.
21.2.14 If detectors above a perforated false ceiling are used for protection of the area below the false ceiling, all of the following recommendations should be met.
21.2.15 In all other cases, detectors should be mounted below the false ceiling, and if protection of the void above the false ceiling is necessary (see 21.2.3), further detectors should be installed on the true structural ceiling within the void.
21.2.16 Detectors should not be mounted within 1 m of any air supply point of a ventilation system. Where air is forced through a perforated ceiling, the ceiling should be imperforate for a radius of at least 600 mm around each detector (see Figure 19).
21.2.17 Detectors should be sited such that a clear space of 500 mm is maintained below each detector (see Figure 20).
80 21.3 Siting of carbon monoxide fire detectors
21.4 Siting of optical beam smoke detectors
21.4.1 Optical beam smoke detectors should be sited in such a way that the horizontal distance between any point in the protected space and the centre line of the optical beam does not exceed 7.5 m (see Figure 21).
21.4.2 If the protected area has a pitched ceiling, for optical beam smoke detectors at or near the apex, the horizontal distance between any point in the protected space and the centre line of an optical beam should not exceed 7.5 m plus an increase …
21.4.3 In apex roofs, where practicable due to the layout of the ceiling, optical beam smoke detectors should be sited at or near each apex (see Notes to 21.4.2). For roofs with a pitch deeper than 600 mm, optical beam smoke detectors should be within…
81 21.4.4 In voids (see 21.4.6), and where practicable due to the layout of the ceiling, optical beam smoke detectors should be sited on ceilings, such that their sensitive elements are between 25 mm to 600 mm.
21.4.5 Where optical beam smoke detectors are installed at a distance of more than 600 mm below ceiling level (or 600 mm below the apex of a pitched roof), the following recommendations should be met.
21.4.6 In unventilated voids not greater than 1.5 m in depth, the sensing element of optical beam smoke detectors should be sited within the top 10% of the void or the top 125 mm, whichever is the greater (see Figure 11). Voids greater than 1.5 m in d…
82 21.4.7 Where an area contains partitions or storage racks that reach within 300 mm of the ceiling, the partitions or storage racks should be treated as walls that extend to the ceiling (see Figure 13).
21.4.8 Ceiling obstructions, such as structural beams, deeper than 10% of the overall ceiling height should be treated as walls (see Figure 14). Within horizontal voids, beams or obstructions that are deeper than 10% of the overall depth of the void, …
21.4.9 If detectors above a perforated false ceiling are used for protection of the area below the false ceiling, all of the following recommendations should be met.
21.4.10 Where optical beams run closer than 500 mm to any wall, partition or obstruction to the flow of hot gases, such as structural beams and ductwork, then that section of the optical beam should be discounted from providing detection.
21.4.11 If there is a probability of people walking within the area of the optical beam, then the optical beam should be at least 2.7 m above floor level. The optical beam detector should be mounted at such a height as to avoid the possibility of the …
21.4.12 Transmitters, receivers and any reflectors should be mounted on solid construction that is not subject to movement, or likely to adversely affect the alignment of the optical beam, as a result of changes in temperature or imposed load.
21.4.13 The path length of the optical beam should not exceed that recommended by the manufacturer.
21.4.14 The area covered by an optical beam smoke detector should not exceed that of a single detection zone given in Clause 12.
83 21.5 Siting of line heat detectors
21.5.1 Line heat detectors should be sited in such a way that the horizontal distance between any point in the protected space and the nearest point on a line heat detector does not exceed 5.3 m.
21.5.2 If the protected area has a pitched ceiling, for line heat detectors at or near the apex, the horizontal distance between any point in the protected space and the nearest point on a line heat detector should not exceed 5.3 m plus an increase of…
84 21.5.3 In apex roofs, line heat detectors should be sited at or near each apex (see also Notes to 21.5.2). For roofs with a pitch deeper than 150 mm, fire detectors should be within the top 150 mm (see Figure 10) and increased coverage should be appli…
21.5.4 Other than within rooms in a Category L3 system (see 21.5.6), in voids (see 21.5.7) or where a horizontal ceiling comprises a series of small cells (see 21.5.11 and 21.5.12), line heat detectors should be sited on ceilings, such that their sens…
21.5.5 Line heat detectors within rooms that open onto escape routes in a Category L3 system should either be sited in accordance with 21.2.5 or be sited on a wall, close to any door that opens onto an escape route. Wall-mounted detectors should be si…
21.5.6 In unventilated voids not greater than 1.5 m in depth, the sensing element of line heat detectors should be sited within the top 10% of the void or the top 125 mm, whichever is the greater (see Figure 11). Voids greater than 1.5 m in depth shou…
21.5.7 Where an area contains partitions or storage racks that reach within 300 mm of the ceiling, the partitions or storage racks should be treated as walls that extend to the ceiling (see Figure 13).
21.5.8 Ceiling obstructions, such as structural beams, deeper than 10% of the overall ceiling height should be treated as walls (see Figure 14). Within horizontal voids, beams or obstructions that are deeper than 10% of the overall depth of the void, …
21.5.9 Within horizontal voids, beams or obstructions that are deeper than 10% of the overall depth of the void, regardless of whether the void is above the ceiling or below the floor, should be treated as walls that subdivide the void.
21.5.10 Where obstructions are installed close to the ceiling, these obstructions should be treated as a wall if:
85 21.5.11 Where a horizontal ceiling comprises a series of small cells (a honeycomb ceiling), detector spacing and siting should be in accordance with Table 1, Figure 15 and Figure 16. The shortest dimension should be taken as the width of a cell.
21.5.12 Where there are a number of closely spaced structural beams (approximately 1 m or less from centre to centre), such as floor joists, the following recommendations should be met.
21.5.13 If detectors above a perforated false ceiling are used for protection of the area below the false ceiling, all of the following recommendations should be met.
21.5.14 Other than where a line heat detector is within 500 mm of its control equipment, where the detector runs closer than 500 mm to any wall, partition or obstruction to the flow of hot gases (such as structural beams and ductwork), then that secti…
21.5.15 Where a line heat detector is installed to protect a particular item of plant or cabling, as opposed to providing general area protection, the detector should be mounted as close as possible to the place where fire or overheating might occur, …
21.6 Siting of aspirating smoke detection systems
21.6.1 Where an aspirating smoke detection system is intended to provide general area protection, and provided that a single sampling point has equivalent sensitivity to a point smoke detector, each aspirating sampling point should be regarded as a po…
21.6.2 Where an aspirating smoke detection system is intended to provide very early warning that is supplementary to other forms of automatic fire detection (e.g. by monitoring return air to air conditioning equipment or monitoring specific items of e…
21.6.3 Where an aspirating smoke detection system is used to protect spaces with high ceilings (>25 m) and there is a risk that the smoke could stratify before reaching the ceiling, sampling should be provided at multiple levels using drop-pipe arrang…
86 21.7 Siting of flame detectors
21.7.1 Spacing of flame detectors should be within maximum limits specified by the manufacturer.
21.7.2 Where flame detectors are intended to provide general area protection, there should be a clear line of sight between all points within the protected area and one or more flame detectors.
21.7.3 Where flame detectors are intended to provide protection for a specific hazard(s), there should be a clear line of sight between the hazard(s) and one or more flame detectors.
21.8 Limits of ceiling height
21.8.1 For ceilings over large, open areas, heat, smoke and combustion gas detectors should not be mounted on ceilings higher than the limits recommended in Table 3, as follows.
21.8.2 For ceilings over large, open areas, multi-sensor detectors should not be mounted on ceilings higher than the limits recommended in Column 1 of Table 3, taking into account the lowest limit expressed for the type of detection and mode of operat…
21.8.3 The limits given in Table 3 should not be used for vertical or flue-like structures, such as lift shafts and stairwells, but may be adapted for such structures (see Note 1 and Note 2).
87 21.9 Smoke detectors in ventilation ducts
21.9.1 The recommendations given in 21.9.2 to 21.9.4 should be met where smoke detectors are provided within air extraction ducts.
21.9.2 Smoke detectors or duct probes should be installed in straight stretches of ductwork, at a distance downstream from the nearest bend, corner or junction of at least three times the width of the duct.
21.9.3 The suitability of the smoke detector for this type of application should be determined from guidance produced by the manufacturer.
21.9.4 The sampling inlet probe and the holes in the probe should be arranged, according to the manufacturer’s instructions, to cover as much of the duct as possible.
22 Control and indicating equipment
88 22.1 Siting of CIE
22.1.1 Indicating equipment, in conjunction with suitable manual control facilities, should be sited at an appropriate location for both staff and firefighters responding to a fire signal, such that controls can be readily operated and indications are…
22.1.2 All control, indicating and power supply equipment that is likely to need routine attention for maintenance should be sited in readily accessible locations that facilitate safe maintenance work.
22.1.3 The ambient light level in the vicinity of all CIE should be such that visual indications can be clearly seen, controls easily operated and any instructions or legends can be easily read.
22.1.4 The ambient noise level in the vicinity of all CIE should not be such as to prevent audible indications (such as the fault warning sounder) from being heard.
22.1.5 The fire alarm CIE, extra low voltage (ELV) power supply equipment for the CIE and other essential control facilities should be sited in areas of low fire hazard level, so that the equipment is unlikely to be involved in a fire before adequate …
89 22.1.6 In Category L and Category P systems, the area(s) in which any CIE(s), power supply (or supplies) for the CIE and other essential control facilities should be protected by automatic fire detection, unless:
22.1.7 In premises in multiple occupation with communal parts, main CIE should be located within a communal area, such as an entrance hall. Where no communal parts exist, the equipment should be sited in an area to which access is possible at all time…
22.2 Facilities provided for visual indication of fire signals
22.2.1 The indicating facilities should be suitable for the fire and evacuation procedures intended for the building. In complex premises, there should be consultation between the interested parties (see Clause 5) to determine which indicating facilit…
22.2.2 The primary indication of the area(s) from which a fire signal(s) has originated should comprise an indication of the zone.
22.2.3 The form of zone indication should comprise a separate light-emitting indicator for each zone of the system (e.g. a LED matrix or illuminated mimic diagram), such that the indicating equipment is capable of simultaneous display of fire signals …
22.2.4 If a visual display unit (VDU) is used to provide the display recommended in 22.2.2:
22.2.5 On or adjacent to indicating equipment, there should be a diagrammatic representation of the building, showing at least the building entrances, the main circulation areas and the division into zones. The diagrammatic representation should compr…
90 22.3 Facilities provided for control of the system
22.3.1 The control facilities should be suitable for the fire and evacuation procedures intended for the building. In complex premises, there should be consultation between the interested parties (see Clause 5) to determine which control facilities ne…
22.3.2 In addition to the sounder silence and re-sound control provided by the CIE, there should also be an evacuate control. A clearly labelled facility should be provided on or immediately adjacent to the control equipment to enable fire alarm sound…
22.3.3 Where the premises are divided into two or more alarm zones (see 3.4), the strategy for phased evacuation should be implemented by the system designer (see 18.1). Normally a separate evacuate control, conforming to 22.3.2, should be provided fo…
22.3.4 The operation of certain manual controls (for example, a disablement control) should be limited to authorized personnel. Where this limitation is not provided on the control equipment (for example, by use of a key operated switch), then it shou…
23 Networked systems
91 23.1 Sub-panels not required for indication purposes should still be readily accessible for maintenance purposes.
23.2 The communications link between sub-panels should be monitored in accordance with 12.1 for wired networks and BS EN 54-25:2008, 4.2.6, for radio networks.
23.3 A fault on the communications link between sub-panels should not affect the operation of any sub-panel.
23.4 In networked systems in which the communications link forms a critical signal path and comprises one or more cables, the cable installation should conform to Clause 25, except that standard fire-resisting cables may be used in all circumstances i…
23.5 The delay between operation of any manual call point and the giving of an “Evacuate” signal in, at least, the alarm zone within which the manual call point should not exceed 3 s. The delay in the giving of appropriate alarm signals in alarm zones…
23.6 In networked systems in which the communications link forms an ancillary circuit and comprises one or more cables, the cable installation should conform to Clause 25 for the ELV supply from an external power supply unit.
24 Power supplies
92 24.1 Mains power supplies
24.1.1 The recommendations in this subclause should be met for the low voltage mains supply to the system. This supply should be treated as an integral part of the fire detection and fire alarm system, regardless of whether the electrical installation…
24.1.2 For reasons of electrical safety, the mains supply to all parts of the fire detection and fire alarm system should be supplied, via an isolating protective device (such as a circuit-breaker), from the load (“dead”) side of the main isolating de…
24.1.3 The mains supply final circuit(s) to all parts of the fire detection and fire alarm system should be dedicated solely to the fire detection and fire alarm system, and should serve no other systems or equipment. The circuit(s) should be derived …
93 24.1.4 To facilitate local isolation during maintenance, suitable means should be provided for local isolation of the low voltage supply circuit that serves the power supply and control equipment. The isolation facilities should be suitably sited, in …
24.1.5 The number of isolating devices between the incoming power supply to the building and the fire detection and fire alarm system power supply unit should be kept to the minimum practicable.
24.1.6 In certain systems within very large buildings, in which networked control panels or distributed power supply units are used, if the mains power supply to this equipment is derived from one or more local distribution boards in the building (as …
24.1.7 Every isolator and protective device that can isolate the supply to the fire detection and fire alarm system, other than the main isolator for the building, should be labelled either:
24.1.8 Labels should be clear and in durable fade-resistant material.
24.1.9 Every isolator, switch and protective device that is capable of disconnecting the mains supply to the fire detection and fire alarm system should either be situated in a position inaccessible to unauthorized persons or be protected against unau…
24.1.10 The circuit supplying the fire detection and fire alarm system should not be protected by a residual current device unless this is necessary to conform to BS 7671:2018+A2. Where a residual current device is necessary for electrical safety, a f…
94 24.1.11 Irrespective of the condition of any standby battery (e.g. disconnected or fully discharged), the mains power supply should be capable of supplying the maximum alarm load of the system (see 3.41).
24.2 Fire detection and fire alarm system power supply units
24.2.1 The recommendations in 24.2.2 to 24.2.5 should be met for every power supply unit that forms part of the fire alarm system.
24.2.2 Transition between the normal supply and the standby supply, and vice versa, should not cause any interruption to the operation of the system or result in a false alarm.
24.2.3 A fault in the normal supply should not adversely affect the standby supply or vice versa. The operation of a single protective device should not result in failure of both the normal and the standby supply.
24.2.4 The presence of the normal or the standby supply should be indicated by a green indicator, located in a position that makes it readily obvious to any person responsible for monitoring faults on the fire detection and fire alarm system (e.g. at …
24.2.5 Normal and standby supplies should each be independently capable of supplying the maximum alarm load of the system (see 3.41), irrespective of the condition of the other supply.
24.3 Standby supplies
24.3.1 The standby supply should comprise a secondary (rechargeable) battery with an automatic charger.
24.3.2 The secondary battery should be of a type having a life of at least 4 years under the conditions of use likely to be experienced in the fire detection and fire alarm system. Automotive batteries (of the type used for starting car engines) shoul…
24.3.3 The date of installation should be indicated. To achieve this, either:
24.3.4 The charging rate of the battery should be such that, having been discharged to its final voltage, the battery can be charged sufficiently to reach the capacity recommended in 24.3.5 after a charging period of 24 h.
24.3.5 When calculated in accordance with Annex D, the capacity of standby batteries should be as follows.
95 24.3.6 If additional CIE is provided over and above that recommended in Clause 22, and the additional equipment is used as the normal method of indication of fire to persons responsible for monitoring the system, a standby supply should be provided fo…
25 Cables, wiring and other interconnections
96 25.1 The electrical characteristics of all cables, such as voltage drop for the ELV supply from an external power supply, current-carrying capacity, impedance and, where appropriate, ability to transmit data, should be in accordance with BS 7671:2018+A2.
25.2 Cables used for all parts of the critical signal paths (see 3.16), for the ELV supply from an external power supply unit and for the final circuit providing low voltage mains supply to the system, should conform to 25.5 or 25.6 and comprise one o…
97 25.3 Cable systems used for all parts of the critical signal paths, and for the low voltage mains supply to the system, should resist the effects of fire. For most fire detection and fire alarm systems, standard fire-resisting cables (see25.5) should …
25.4 For fire detection and fire alarm systems for the following applications, cable systems comprising enhanced fire-resisting cables (see 25.6), with appropriate methods of support (see 35.3) and jointing (see 35.4), should generally be used:
25.5 Standard fire-resisting cables should have a duration of survival of 30 min when tested in accordance with BS EN 50200:2015, including the optional water spray test in BS EN 50200:2015, Annex E.
25.6 Enhanced fire-resisting cables should have a duration of survival of 120 min when tested in accordance with BS EN 50200:2015 and with BS 8434-2.
25.7 All conductors should have a cross-sectional area of not less than 1 mm2.
25.8 Where multicore cable is used for interconnection of fire alarm circuits, none of the conductors should be used for circuits other than those of the fire alarm system.
98 25.9 All fire alarm cables and the low voltage mains supply should be of a single, common colour that is not used for cables of general electrical services in the building, to enable these cables to be distinguished from those of other circuits.
100 26 Radio-linked systems
26.1 Components of a radio-linked system should conform to BS EN 54-25.
101 26.2 Although BS EN 54-25 permits the use of a single battery in each device, radio-linked systems should also meet the following recommendations.
26.3 Cables of antennae that are external to components of a radio-linked system should be monitored for open and short circuits. A fault condition should be given at the CIE within 300 s of the occurrence of such a condition.
26.4 Cables of antennae that are external to components that form part of the critical signal path should either:
26.5 If facilities are provided for automatic silencing of radio-linked fire alarm sounders, they should meet the recommendations in 15.1.8.
26.6 Unless the visual indication at the detector of initiation of a fire alarm signal is manually reset at the control panel, it should remain illuminated for not less than 20 min after initiation.
26.7 Installation of a radio-linked system should take place only after a comprehensive radio survey has been undertaken to ascertain the following:
102 26.8 Only radio survey test equipment that has been approved by the manufacturer, and regularly calibrated in accordance with the manufacturer’s recommendations, should be used to carry out the survey.
26.9 At the time of commissioning and after the installation of all equipment, including remote antenna(e), the following records relating to the radio data should be recorded where applicable:
26.10 The signal levels recorded should be within the specifications set by the manufacturer of the radio system.
26.11 A copy of the signal levels should be kept on site with the system logbook.
27 Electromagnetic compatibility
27.1 Fire detection and fire alarm systems should be so designed and installed that they do not cause, and are not unduly susceptible to, electromagnetic interference. The manufacturer’s recommendations in respect of electromagnetic compatibility shou…
103 27.2 Every system component should satisfy the relevant requirements of the product standard for that component in respect of electromagnetic capability (see Clause 20).
27.3 Cables should be segregated in accordance with 35.8 and 35.9.
27.4 Installation workmanship should meet the relevant recommendations in Section 4. For mineral insulated copper sheathed cables, terminations of screens should be effective around the entire 360 of the screen. For other cables, the screen of the ca…
27.5 Any cable specifications stipulated by the manufacturer should be adhered to, provided that they meet the recommendations in Clause 25. Where these cables do not meet the recommendations in Clause 25, they should be used only with the prior agree…
27.6 Equipment should be earthed in accordance with Clause 28 and 35.10.
27.7 Exposure of the cores outside of the screen should be kept to a minimum, consistent with practical installation requirements.
27.8 Where required, the screen should have continuity throughout the whole circuit (see 35.10).
27.9 Where it is necessary to cross fire detection and fire alarm system cables with those that can potentially cause interference, the cables should be crossed at right angles.
28 Electrical earthing
28.1 The system design should be such as to satisfy the relevant requirements of BS 7671:2018+A2.
28.2 The colour of the functional-earth sleeving required by BS 7671:2018+A2 should be used for fire alarm installations.
28.3 The CIE manufacturer’s instructions or product marking should be followed.
28.4 LV and ELV circuits should be segregated throughout in accordance with Clause 27 and 35.9. If any ELV fire alarm cables share the same wiring containment with other cables, the cable insulation of the fire alarm cables should be rated for the hig…
28.5 For ELV circuits with removable components (e.g. detectors or parts of detectors) that expose to touch conductive circuit parts at ELV potential, the following recommendations should be met.
105 Section 3: Limitation of false alarms and unwanted fire alarm signals
29 Responsibility for limitation of false alarms and unwanted fire alarm signals
29.1 The system designer should record on the design certificate (see Clause 39) the measures incorporated within the design to limit false alarms and unwanted fire alarm signals.
29.2 Where an installer identifies any circumstances that might lead to a high rate of false alarms and unwanted fire alarm signals, the designer, purchaser or user should be informed accordingly (see also 6.2).
29.3 At commissioning, a check should be carried out to verify that there is no obvious potential for an unacceptable rate of false alarms and unwanted fire alarm signals.The completion of the check should be recorded on the commissioning certificate …
29.4 The designer and the supplier of the system should jointly provide the user (or a suitable representative of the user) with sufficient information to enable a user who is unfamiliar with the technology of fire detection and fire alarm systems to …
29.5 Any person responsible for verification of the compliance of a system with this part of BS 5839 (see Clause 41) should verify, as far as reasonably practicable, that the need to limit false alarms has been taken into account in the design, instal…
106 29.6 The commissioning/handover organization should advise the user to arrange for suitable investigation and, if appropriate, action to be taken on every occasion that a false alarm occurs.
29.7 The commissioning/handover organization should advise the user to record appropriate details regarding every false alarm and/or unwanted fire alarm signal that occurs. Information recorded should include:
30 Categories and causes of false alarms
107 30.1 Any person responsible for specification, design, commissioning or maintenance of fire detection and fire alarm systems should be conversant with the major causes of false alarms. The potential for unwanted alarms and malicious false alarms shoul…
30.2 The user should be advised that where false alarms are recorded (see 29.7), the category of false alarm (if known) should also be recorded. Where any doubt exists, the cause should be recorded as “unknown” (e.g. it should not be assumed that, in …
31 Investigation of false alarms
108 31.1 At the time of every service visit, the system false alarm record should be checked to determine the following:
31.2 At least a preliminary investigation should be carried out as part of the service work in any of the following circumstances:
109 31.3 The user should be informed of the outcome of the investigation and be given appropriate advice, including advice regarding the need for a more in-depth investigation.
31.4 For systems that incorporate more than 40 automatic fire detectors, the user should be advised to instigate an in-depth investigation by suitable specialists if, in any rolling period of 12 months, either:
31.5 For systems that incorporate fewer than 41 automatic fire detectors, the user should be advised to instigate an in-depth investigation, as described in 31.4, if, in any rolling 12 month period, more than two false alarms occur.
32 Design process for limitation of false alarms and unwanted fire alarm signals
32.1 At the design stage of every system, the potential for false alarms and unwanted fire alarm signals should be assessed, to determine whether the design is such that the frequency of false alarms and unwanted fire alarm signals is likely to be acc…
110 32.2 Each major area of the building should be assessed separately, with an iterative design process being undertaken if necessary. If the initial design is found to be inadequately robust in its limitation of false alarms and unwanted fire alarm sign…
32.3 Any relevant design information regarding false alarms and unwanted fire alarm signals should be recorded and documented in accordance with Clause 38.
33 Measures to limit false alarms and prevent unwanted fire alarm signals
33.1 Selection and siting of manual call points
33.1.1 In existing systems in which there is frequent unwanted operation of manual call points, protective covers should be fitted (see 19.2.
33.1.2 Manual call points should not be sited where they are likely to be exposed to accidental damage (e.g. by normal operations in the building, trolleys or forklift trucks), unless such siting is necessary to meet the recommendations in Clause 19. …
33.1.3 In areas in which manual call points are exposed to moisture, water-resistant devices should be used.
33.1.4 To minimize the potential for malicious operation, manual call points should not normally be located within the malls of covered shopping complexes.
33.2 Selection and siting of automatic fire detectors
33.2.1 In areas with high levels of dust and dirt which could contaminate detectors and/or lead to an unwanted alarm, aspirating smoke detectors should be used as the first preference, provided that they incorporate mechanical filtration of the air sa…
111 33.2.2 In areas in which automatic fire detectors are likely to result in a high level of unwanted alarms, they should only provided where they are necessary to satisfy the objectives of the fire detection and fire alarm system (see Clause 4).
33.2.3 Since, in most premises, heat detectors are likely to give rise to lower rates of unwanted alarms than other forms of automatic fire detector, other types should not be used unless heat detectors would be insufficent to satisfy both the objecti…
33.2.4 The minimum static response temperature (see 3.43) of heat detectors should be at least 29 C above the normal operational temperature of the air surrounding the detector, and at least 4 C above the maximum short-term temperature of the air su…
33.2.5 Rate of rise heat detectors should not be installed in locations in which rapid fluctuations in temperature might occur (e.g. kitchens, boiler rooms, loading bays with large doors to open air and lantern-lights).
33.2.6 Optical beam smoke detectors should not be installed in areas in which obstruction of the beam might occur in normal circumstances.
33.2.7 Where optical beam smoke detectors are installed in any area, they should be suitably mounted (see 21.4.12).
33.2.8 Where there is likely to be a high false alarm rate from point-type smoke detectors, multi-sensor detectors should be used.
33.2.9 High sensitivity (Class A) or enhanced sensitivity (Class B) aspirating smoke detection systems should not be used if they are likely to result in an unacceptable rate of unwanted alarms.
33.2.10 Carbon monoxide fire detectors should not be used in locations in which carbon monoxide might occur, under normal circumstances, in quantities sufficient to create the potential for unwanted alarms.
112 33.2.11 Carbon monoxide fire detectors should not be used in locations in which contamination of the electro-chemical cell could result in unwanted alarms. The guidance of the manufacturer on avoidance of unwanted alarms should be taken into account.
33.2.12 Flame detectors should not be located in areas in which sources of infrared or ultraviolet radiation create the potential for unwanted alarms. The detector manufacturer’s guidance should be followed.
33.3 Selection of system type
Systems that incorporate a high number of smoke detectors should be addressable or analogue addressable.
33.4 Protection against electromagnetic interference
33.4.1 Equipment should be sited such as to avoid the likely sources of electromagnetic radiation in the building (e.g. mobile telephones, two-way radios, mobile telephone base stations and other high power transmitters).
33.4.2 In cases where unusually high electromagnetic field strengths occur (e.g. radio transmitter sites, airport terminals and radar stations), guidance should be sought from the system manufacturer in respect of suitability of the proposed system an…
33.5 Performance monitoring of newly commissioned systems
33.5.1 In the case of systems incorporating more than 50 automatic fire detectors, after commissioning, a soak period (see 3.62) should follow. The duration of the soak period should be defined by the designer but should be not less than one week. Sys…
33.5.2 Until successful completion of the soak test, the system should not be regarded as the operational means of giving warning of fire in the building. During the soak period, each manual call point should bear an indication that it is not to be used.
33.5.3 The soak test should be regarded as successfully completed only if:
33.6 Filtering of false alarms
113 33.6.1 General
33.6.1.1 Filtering measures should be adopted under the following circumstances:
33.6.1.2 Filtering should not be applied to signals initiated by manual call points, heat detectors or sprinkler systems.
33.6.1.3 In time-related systems, the change of state of the system to unmanned mode should not rely on human action; it should occur automatically at predetermined times. The change of state to manned mode should be by human action at the fire alarm …
114 33.6.1.4 Staff alarms should conform to 18.2.
33.6.1.5 Any arrangements for filtering of automatic summoning of the fire and rescue service by an ARC should conform to BS EN 50518. Such filtering should not be applied to signals from fire alarm systems in residential care premises.
33.6.1.6 Where a signal from an automatic sprinkler system that is supplied from water mains is used as an input to the fire detection and fire alarm system (e.g. by means of a pressure or flow switch), there should be liaison with the organization re…
33.6.2 System management
33.6.2.1 The user should be informed that staff in the building and visiting contractors need to be made aware of the presence of any automatic fire detectors, and of the measures necessary to minimize the likelihood of false alarms and unwanted fire …
33.6.2.2 Tender documents for contract work to be carried out in a protected area should contain a clause making the contractors responsible for informing their staff of the presence of any automatic fire detectors, and of the precautions to be adopte…
33.6.2.3 Where temporary work involving the generation of dust, smoke, paint spray, etc., is to be carried out in an area protected by smoke detectors, precautions should be taken to prevent unwanted alarms.
33.6.2.4 Suitable notification of building occupants, and any ARC to which fire alarm signals are transmitted, should occur prior to routine testing or maintenance work on the fire alarm system that might result in the occurrence of a fire alarm signal.
33.6.2.5 The user should be informed that any building defects (e.g. leaking roofs), plant defects (e.g. steam leaks) and environmental problems (such as inadequate ventilation) that could cause unwanted alarms need to receive suitable attention.
33.6.2.6 All false alarms should be recorded in the system logbook (see 29.7, 30.2 and Clause 48].
115 33.6.2.7 The user should be advised to take appropriate action should be taken when false alarms occur (see 29.6, 31.4 and 31.5).
33.6.3 Service and maintenance
116 Section 4: Installation
34 Responsibility of installer
34.1 The responsibilities associated with the installation of the system should be clearly defined, agreed and documented prior to the commencement of the installation work.
34.2 Manual call points should be installed in accordance with 19.5 to 19.10.
34.3 Point, heat, smoke and carbon monoxide detectors should be installed in accordance with 21.2.4, 21.2.7 and 21.2.13.
34.4 Beam-type smoke detectors should be installed in accordance with 21.4.5, 21.4.10, 21.4.11 and 21.4.12 and any manufacturer’s recommendations for the mounting distance below the ceiling.
34.5 Line heat detectors should be installed in accordance with 21.5.3, 21.5.4, 21.5.6, 21.5.7, 25.1.8, 21.5.13 and 21.5.15.
34.6 Smoke detectors in ventilation ducts should be installed in accordance with 21.9.2 and 21.9.4.
34.7 Where an installer identifies any circumstances that might lead to a high rate of false alarms, the designer, purchaser or user should be informed accordingly (see also 6.2).
34.8 The mains power supplies to the fire alarm system should be installed in accordance with 24.1.
34.9 All equipment that is likely to need routine attention for maintenance should be sited in readily accessible locations that facilitate safe maintenance work.
34.10 All metallic parts of the installation, including conduit, trunking, ducting, cabling and enclosures, should be separated from any metalwork forming part of a lightning protection system.
117 34.11 The installer should provide as-fitted drawings to the purchaser or user of the system, in accordance with Clause 38c), unless it has been agreed that this is to be the responsibility of a different person or organization.
34.12 On completion of the installation work, the installer should issue an installation certificate, signed by a competent person.
34.13 If the designer accepts responsibility for variations and this is communicated in the form of specific written requirements (e.g. within a specification), the installer should record these variations within the installation certificate.
35 Installation practices and workmanship
35.1 Installation practices and workmanship should conform to BS 7671:2018+A2, except where otherwise recommended in this part of BS 5839.
35.2 Cables which are directly fixed to surfaces should be neatly run and securely fixed at suitable intervals, in accordance with the cable manufacturer’s recommendations. Cables should not rely on suspended ceilings for their support.
35.3 Methods of cable support should be non-combustible3F ) and such that circuit integrity is not reduced below that afforded by the cable used, and should be capable of withstanding a similar temperature and duration to that of the cable.
35.4 Cables should be installed without external joints wherever practicable. All terminations and other accessories should be such as to minimize the probability of early failure in the event of fire. Other than in the case of joints at or within sys…
118 35.5 To avoid the risk of mechanical damage to fire alarm cables, they should not be installed within the same conduit as the cables of other services. Where fire alarm cables share common trunking, a compartment of the trunking, separated from other …
35.6 Where cables are used with no additional mechanical protection, they should be mineral insulated copper sheathed cables conforming to BS EN 60702-1 and BS EN 60702-2) or steel wire armoured cables conforming to BS 7846. Cables that do not conform…
35.7 Where conduit is used to satisfy the recommendations given in 35.6, the conduit should conform to the relevant part of BS EN 61386. Any non-metallic trunking used in the system should conform to BS EN 50085-1.
35.8 To avoid electromagnetic interference with fire alarm signals, any recommendations by the manufacturer of the fire alarm equipment in respect of separation of fire alarm cables from the cables of other services should be followed.
35.9 Fire alarm cables carrying power in excess of ELV should be segregated from ELV fire alarm circuits by use of cables conforming to 25.2 and with 35.8. The mains supply cable to any control, indicating or power supply equipment should not enter th…
35.10 Arrangements for earthing should be in accordance with the manufacturer’s recommendations. The electrical continuity of electromagnetic screens, including metallic sheaths of cables, should be maintained (see Figure 23 and Figure 24).
35.11 Where new conduit, trunking or tray is installed, its capacity should be in accordance with BS 7671:2018+A2.
35.12 Where a cable passes through an external wall, it should be contained in a smooth-bore sleeve of metal or other non-hygroscopic material sealed into the wall. This sleeve should slope downwards towards the outside and should be plugged with a su…
35.13 Where a cable passes through an internal wall, a small clearance hole should be provided. If additional mechanical protection is necessary, a smooth-bore sleeve should be sealed into the wall.
35.14 The ends of any sleeves should be free from sharp edges which might damage cables during installation.
35.15 When a cable passes through a floor, the recommendations in 35.12, 35.13 and 35.14 should be met. In addition, the sleeve should extend as far above floor level as is required for protection of the cable it is to carry, up to a maximum height of…
35.16 Where cables, conduits, trunking or tray pass through floors, walls, partitions or ceilings, the surrounding hole should be as small as reasonably practicable and made good with fire-stopping materials providing fire resistance not less than tha…
119 35.17 If cables or conduits are installed in channels, ducts, trunking or shafts that pass through floors, walls, partitions or ceilings, barriers with the appropriate level of fire resistance should be provided within the channels, etc. to prevent th…
120 36 Inspection and testing of wiring
36.1 For all installed cables with a manufacturer’s voltage rating suitable for mains use, when tested at 500 V DC, the insulation resistance between conductors, between each conductor and earth, and between each conductor and any screen, should be at…
36.2 Earth continuity and, for mains supply circuits, earth fault loop impedance, should conform to BS 7671:2018+A2.
36.3 On completion of the installation work, the following tests should be carried out, unless there is specific agreement that they are to form part of the commissioning process:
36.4 The results of all tests should be recorded and made available to the organization responsible for commissioning the system.
121 Section 5: Commissioning and handover
37 Commissioning
37.1 The recommendations in 37.1 to 37.9 should be met for new systems, and to modifications and additions to existing systems.
37.2 The system should be commissioned by a competent person (see 3.14) who has access to the requirements of the designer (i.e. the system specification) and any other relevant documentation or drawings.
37.3 Any person responsible for commissioning a fire detection and fire alarm system in accordance with the recommendations of this part of BS 5839 should possess, at least, a basic knowledge and understanding of Section 2, Section 3 and Section 4.
37.4 At commissioning, the entire system should be inspected and tested to verify that it operates satisfactorily and that, in particular:
123 37.5 All fault indicators and their circuits should be checked, where practicable, by simulation of fault conditions.
37.7 Unless already undertaken and documented by the installer, the tests recommended in 36.3 should be carried out and the results recorded. Where specifically agreed that the tests recommended in 36.3 should be carried out at commissioning, these te…
37.8 Labels, visible when batteries are in their normal position, should be fixed to batteries, indicating the date of installation.
37.9 On completion of commissioning, a commissioning certificate signed by a competent person should be issued.
38 Documentation
124 39 Certification
39.1 On, or as soon as practicable after, completion of each of the following processes, a certificate should be issued by the organization responsible for the process, certifying compliance with the recommendations of this part of BS 5839 in respect …
125 39.2 Where modifications are carried out to a fire detection and fire alarm system, the recommendations in 44.2 should be met.
40 Handover
40.1 Acceptance procedures should be carried out in accordance with the agreed purchase specification (see 5.6), including any tests that are to be witnessed and details of the witnessing procedure.
40.2 Before a system is accepted, the organization handing over the system should ask the purchaser (or appropriate representative of the purchaser) to check that:
126 40.3 As evidence of acceptance, the organization handing over the system should ask the purchaser (or appropriate representative of the purchaser) to sign an acceptance certificate (see Clause 39).
41 Verification
41.1 Any person responsible for verification should be competent in the design of fire detection and fire alarm systems in accordance with this part of BS 5839, and familiar with the relevant installation practices.
41.2 If the purchaser or user requests verification of conformity to this part of BS 5839, the scope and extent of the verification process should be agreed between the purchaser or user and the verifying organization.
41.3 On completion, a verification certificate should be issued. The certificate should also contain information on the scope and extent of the verification carried out or identify where this information is available (e.g. a report).
127 Section 6: Maintenance
42 Routine testing
42.1 Weekly testing
42.1.1 The manufacturer’s recommendations regarding weekly testing should be followed.
42.1.2 Every week (see Note 3), a manual call point should be operated during normal working hours. It should be confirmed that the control equipment is capable of processing a fire alarm signal and providing an output to fire alarm sounders, and that…
42.1.3 The weekly test should be carried out at approximately the same time each week; occupants should then be instructed that they should report any instance of poor audibility of the fire alarm signal. In systems with staged alarms incorporating an…
42.1.4 In premises in which some employees only work during hours other than that at which the fire detection and fire alarm system is normally tested, an additional test(s) should be carried out at least once a month so that these employees can becom…
42.1.5 A different manual call point should be used at the time of every weekly test, so that all manual call points in the building are tested in rotation over a prolonged period. The result of the weekly test and the identity of the manual call poin…
42.1.6 The duration for which any fire alarm signal is given (other than solely at CIE) at the time of the weekly test should be at least 5 s, but should not normally exceed 60 s, so that, in the event of a fire at the time of the weekly test, occupan…
42.1.7 Voice alarm systems should be tested weekly in accordance with BS 5839-8.
128 42.2 Monthly checks
42.2.1 If an automatically started emergency generator is used as part of the standby power supply (see 24.3.5), it should be started up once each month by simulation of failure of the normal power supply and operated on-load for at least 1 h. The tes…
42.2.2 If vented batteries are used as a standby power supply, a visual inspection of the batteries and their connections should be made to verify that they are in good condition. Action should be taken to rectify any defect, including low electrolyte…
43 Inspection and servicing
43.1 Quarterly inspection of vented batteries
43.2 Periodic inspection and test of the system
43.2.1 For all detectors, tests should be carried out to verify that products of combustion are capable of passing unhindered from the protected area to the sensing chamber/elements of the detector, and not simply to test the ability of the detector t…
43.2.2 The recommendations in this subclause should be carried out by a competent person (see 3.14). Successive inspection and servicing visits should be undertaken at intervals of approximately 6 months (see Note 1).
129 43.2.3 The system logbook should be examined. It should be determined whether any faults recorded have received appropriate attention. Any outstanding faults should be reported to the premises management for appropriate action to be taken.
43.2.4 A visual inspection should be made to check whether structural or occupancy changes have affected the conformity of the system to this part of BS 5839 for the siting of manual call points, automatic fire detectors and fire alarm devices. The fo…
43.2.5 The records of false alarms should be checked and the rate of false alarms during the previous 12 months should be recorded (see 31.1). Further investigation should be carried out where necessary (see 31.2).
43.2.6 The steady state charge voltage of the battery should be measured with the mains on to verify that it is within the manufacturer’s recommendations. This should be done before any other tests that might discharge the battery, and with no load on…
43.2.7 The standby battery should be disconnected, the alarms activated and the power supply output voltage checked to verify that it is close to the nominal voltage.
43.2.8 Batteries and their connections should be examined and momentarily load tested with the mains disconnected (other than those within devices such as manual call points, detectors and fire alarm sounders of a radio-linked system), to verify that …
43.2.9 The fire alarm functions of the CIE should be checked by the operation or functional testing of at least one detector or manual call point on each circuit. An entry should be made in the logbook indicating which initiating devices have been use…
43.2.10 It should be verified that a fire alarm signal is given on operation or functional testing of at least one manual call point or fire detector.
43.2.11 All controls and visual indicators at CIE should be checked for correct operation, and any timeclock should be checked and adjusted appropriately.
130 43.2.12 The operation of any facility for automatic transmission of alarm signals to an ARC should be checked. Where more than one form of alarm signal can be transmitted (e.g. fire and fault signals), the correct transmission of each signal should be…
43.2.13 All ancillary functions of the system should be tested.
43.2.14 All fault indicators and their circuits should be checked, where practicable, by simulation of fault conditions.
43.2.15 All printers should be tested to verify that they operate correctly and that characters are legible.
43.2.16 All printer consumables should be sufficient in quantity or condition that the printer can be expected to operate until the time of the next service visit.
43.2.17 Radio systems of all types should be serviced in accordance with the manufacturer’s recommendations.
43.2.18 All further checks and tests recommended by the manufacturer of the CIE and other components of the system should be carried out.
43.2.19 Where the process of servicing involves the disablement of protection in significant parts of the system, this should be kept to a practicable minimum, and the premises management or their appointed representative should be informed of the are…
43.2.20 Following the work carried out in 43.2.1 to 43.2.19, any outstanding defects should be reported to the premises management and the logbook (see Clause 48) should be completed.
43.2.21 On successful completion of the work, an inspection and servicing certificate should be issued.
43.3 Inspection and test of the system over a 12-month period
43.3.1 In addition to the work recommended in 43.2, the work described in 43.3.2 to 43.3.26 should be carried out every year.
43.3.2 The switch mechanism of every manual call point should be tested, either by removal of a frangible element, insertion of a test key or operation of the device as it would be operated in the event of fire.
43.3.3 All automatic fire detectors and remote detectors (including any with remote indicators) should be examined, as far as practicable, to verify that they have not been damaged, painted, or otherwise adversely affected. Thereafter, every detector …
43.3.4 Where fitted, detector remote indicators should also be checked for correct operation.
43.3.5 Every heat detector should be functionally tested by means of a suitable heat source, unless operation of the detector in this manner would then necessitate replacement of part or all of the sensing element (e.g. as in fusible link point detect…
131 43.3.6 Point smoke detectors should be functionally tested by a method that demonstrates whether smoke can enter the detector chamber and produce a fire alarm signal (e.g. by use of apparatus that generates simulated smoke or suitable aerosols around …
43.3.7 Optical beam smoke detectors should be functionally tested by introducing signal attenuation between the transmitter and receiver, either by use of an optical filter (or any similar method of simulating obscuration by smoke), smoke or simulated…
43.3.8 Where practicable (see 43.3.9), aspirating fire detection and fire alarm systems should be functionally tested by a method that determines whether smoke can enter the detector chamber and produce a fire alarm signal. Tests should also be undert…
43.3.9 Where access is restricted or other site conditions prevent the tests recommended in 43.3.8 from being undertaken, an appropriate alternative verification technique should be employed, which should be agreed with all parties and recorded.
43.3.10 Carbon monoxide fire detectors should be functionally tested by a method that determines whether carbon monoxide can enter the detector chamber and produce a fire alarm signal (e.g. by use of apparatus that generates carbon monoxide or a gas t…
43.3.11 Flame detectors should be functionally tested by a method that determines whether the detector responds to a suitable frequency of radiation and produces a fire alarm signal. The manufacturer’s guidance on the testing of detectors should be fo…
132 43.3.12 In fire detection systems that enable analogue values to be determined at the CIE, it should be verified that each analogue value is within the range specified by the manufacturer.
43.3.13 Multi-sensor detectors should be operated by a method that determines whether products of combustion in the vicinity of the detector can reach the sensors and that a fire signal can be produced as appropriate. The following specific actions sh…
43.3.14 All fire alarm devices should be checked for correct operation. It should be verified that visual fire alarm devices are not obstructed from view and that their lenses are clean.
43.3.15 All unmonitored, permanently illuminated filament lamp indicators at CIE should be replaced.
43.3.16 Radio signal strengths in radio-linked systems should be checked to verify that they are within the manufacturer’s recommendations (see Clause 26), and the results recorded in the logbook.
43.3.17 A visual inspection should be made to verify that all readily accessible cable fixings are secure and undamaged.
43.3.18 The cause-and-effect programme should be checked by activating at least one cause and observing the operation of the effects. Where there are different types of devices (e.g. manual call points and automatic fire detectors), one cause and its …
43.3.19 The standby power supply capacity should be checked to verify that it remains suitable for continued service.
43.3.20 A check should be made to determine whether a suitable zone plan (or other suitable diagrammatic representation) of the premises is provided on or adjacent to all CIE and repeat indicating equipment.
133 43.3.21 All further annual checks and tests recommended by the manufacturer of the CIE and other components of the system should be carried out.
43.3.22 Video fire detectors should be subject to the manufacturer’s guidelines in relation to annual test and inspection. Any lighting provided specifically to aid the detection of flame or smoke should be regarded as an integral part of the video fi…
43.3.23 During detector testing, all readily visible integral and/or remote visual indicators should be checked for correct operation. It should also be verified that visual indicators are not obstructed from view by changes in their environment or co…
43.3.24 Following the work carried out in 43.1, 43.2 and 43.3, any outstanding defects should be reported to the premises management and the logbook (see Clause 48) should be completed.
43.3.25 On successful completion of the work, an inspection and servicing certificate should be issued.
43.4 Remote services and cybersecurity
43.4.1 Not all systems or applications will require cybersecurity, but if it is required then the following recommendations should be met.
43.4.2 Before any remote service is performed, especially before any read, control or write functions are executed, a risk assessment should be made of the potential impact on the operation of the CIE. If there is any possibility that the remote servi…
44 Non-routine attention
134 44.1 Special inspection on appointment of a new servicing organization
44.1.1 When a servicing organization takes over servicing arrangements for an existing system, they should carry out an inspection, and study existing records (see Clause 38) where these are available, to obtain sufficient information to be documented…
44.1.2 Areas of non-conformity should be documented and identified to the premises management and, although the degree of a non-conformity might be subjective, the following non-conformities should be addressed:
44.1.3 If there is no logbook (see Clause 48), a suitable logbook should be provided by the servicing organization.
135 44.2 Arrangements for repair of faults or damage
44.2.1 Where maintenance is carried out by a third party, such as a fire alarm maintenance organization, there should be an agreement for emergency call out to deal with any fault or damage that occurs to the system. The agreement should be such that,…
44.2.2 The name and telephone number of any third party responsible for maintenance of the system should be prominently displayed at the main CIE, and the records and documentation as identified in Clause 38 should be kept updated.
44.2.3 All faults or damage should be recorded in the system logbook, and arrangements should be made for repair to be carried out as soon as possible.
44.2.4 Where any defect cannot be rectified during the attendance of the servicing organization, any fault indications should not be concealed (i.e. by suppressing the fault indication).
136 Section 7: Extensions and modifications
45 Extensions
45.1 Any work involving the extension of an existing system should conform to this part of BS 5839, albeit that the extended system might not, overall, conform to this part of BS 5839.
45.2 Responsibility for extension of a fire detection and fire alarm system should rest, ultimately, with a person who is competent in at least the basic principles of fire detection and fire alarm system design and is conversant with this part of BS …
45.3 The extended system should be subject to recommissioning in accordance with Clause 37, to the extent applicable for the new work.
45.4 On completion of the recommissioning, an extensions or modifications certificate, signed by a competent person, should be issued.
46 Modifications
137 46.1 General
46.1.1 The recommendations given in 46.1.2 to 46.1.13 should be met for all modification work, regardless of whether it is carried out on site or remotely.
46.1.2 Responsibility for modification of a fire detection and fire alarm system should rest, ultimately, with a person who is competent in at least the basic principles of fire detection and fire alarm system design and is conversant with this part o…
46.1.3 The user should be made aware of any modifications proposed for the system, and their written agreement should be obtained.
46.1.4 Any person carrying out modifications should have access to current as-fitted drawings of the system and to the current system configuration, indicating full details of cause-and-effect logic, available with the system documentation (see Clause…
46.1.5 All components, circuits, system operations and site-specific software functions known to be affected by the modifications should be tested for correct operation following the modifications.
46.1.6 In addition to the tests recommended in 46.1.5, the following tests should be carried out to verify that there is no adverse effect on the overall system.
46.1.7 Where a system has been modified and equipment is no longer in use, to avoid confusion, the redundant devices should either be removed (where practicable), or clearly identified as no longer in use.
46.1.8 On completion of the modifications, all as-fitted drawings, the operation and maintenance manual (including a record of the type and configuration of detectors) and other relevant system records should be updated as appropriate and made availab…
138 46.1.9 On commissioning of the work and completion of the tests, an extensions or modifications certificate should be issued, confirming that the work has been carried out in accordance with this part of BS 5839, or identifying any variations.
46.1.10 Where responsibility for the conformity, or otherwise, of the modified system with Section 2 rests with any person other than the organization carrying out the modification, that person should sign the appropriate section of the extensions or …
46.1.11 Any investigation into an unacceptable rate of false alarms, and any subsequent modifications to the system, should be in accordance with Clause 31.
46.1.12 Any modifications to an existing, older system that does not conform to this part of BS 5839 should not result in additional non-conformities being introduced.
46.1.13 Any relevant documentation should be made available with the system documentation (see Clause 38).
46.2 Inspection and test of the system following a fire
46.2.1 The recommendations given in 46.2.2 to 46.2.5 should be carried out as soon as possible after any fire.
46.2.2 Every manual call point, automatic fire detector and fire alarm device that might have been affected by the fire or fire-fighting action should be inspected and tested in accordance with 43.3.
46.2.3 A visual examination and tests should be carried out on any other part of the system that lies within the fire area and other areas affected by corrosive smoke from the fire and that might have been damaged by the fire (e.g. power supplies, con…
46.2.4 Circuits external to the CIE that could have been affected by the fire should be tested for correct operation.
46.2.5 On completion of the work, any defects found should be recorded in the system logbook, and the premises management should be notified accordingly.
46.3 Inspection and test of the system following long periods of disconnection
139 Section 8: User responsibilities
47 Premises management
47.1 A single, named member of the premises management should be appointed to supervise all matters pertaining to the fire detection and fire alarm system. This person should be given sufficient authority to carry out the following duties and should n…
140 47.2 In the event of a pre-alarm, the following actions should be taken:
48 Logbook
141 Annex A (informative) Choice of appropriate category of fire detection and fire alarm system
143 Annex B (informative) Typical noise levels in buildings
145 Annex C (normative) Control and transmission equipment for tactile alarm devices provided for people who are Deaf or have a hearing impairment
C.1 Control and transmission equipment for tactile alarm devices provided for people who are Deaf or have a hearing impairment should be designed in accordance with BS EN 54-2:1997+A1, other than in respect of the colours used for visual indicators.
C.2 The control and transmission equipment should conform to the following (sub)clauses of BS EN 54-2:1997+A1:
C.3 The design should meet the following recommendations.
C.4 Power supplies should conform to BS EN 54-4.
146 Annex D (normative) Method for calculating standby battery capacity
D.1 Valve-regulated lead acid batteries
D.1.1 The minimum capacity of valve-regulated lead acid batteries should be calculated in accordance with the following formula:
D.1.2 Where Cmin/20 is equal to or greater than I2, it can be assumed that D = 1. When Cmin/20 is less than I2, the value of D should either be based on the battery manufacturer’s data or should be 1.75.
D.1.3 Where Cmin does not correspond exactly to an available battery capacity, the next highest available capacity size should be used.
D.2 Batteries other than valve-regulated lead acid batteries
147 Annex E (informative) Selection and application of fire detectors
154 Annex F (informative) Model format for system logbook
157 Annex G (informative) Model certificates
G.1 Design certificate
160 G.2 Installation certificate
161 G.3 Commissioning certificate
163 G.4 Acceptance certificate
165 G.5 Verification certificate
166 G.6 Inspection and servicing certificate
167 G.7 Extensions or modifications certificate
BSI 24/30473259 DC 2024
$18.97