BS5839 - Fire Alarm Systems

BS

and Alarm systems for BuildingsCode of practice for system design, installation and servicing

BS 1:2002

Fire detection and Alarm systems for BuildingsCode of practice for system design, installation and servicing

Due to the on going and continued advances in Fire Alarm System Technology and the changes in Building Design and Construction the previous British Standard 5839:Part 1:1988 had become out of date. Consequently the Standard taking into account these advances/changes made over the years has been revised. 1. GENERAL BS 5839:Part 1:2002 like its predecessor provides guidance by recommendations from the initial Planning Stage, through the Design, Installation, Commissioning and Final Maintenance of Fire Alarm Systems in and around buildings other than Domestic Dwellings, these being covered by Part 6 of the Standard. It should be noted that the Standard does not recommend or identify whether a Fire Alarm System need be or should be installed within any given premises. This should/must be subject to, in the respect of new buildings, Fire Precautions Act (1971) and Building Regulations.

Existing Buildings consequently are subject to the Workplace Regulations and the subsequent Risk Assessment. It should be noted that the Standard does not cover Extinguishing/Fire Control Systems, Voice Alarms (BS5839:Part 8), 999 Public Emergency Call Systems, Audible/Visual Way Guidance Systems, Critical Electronic Systems (BS 6266) or Fire Alarm Systems covered under NHS Estates Publication HTM 82. NHS Estates Publication HTM 82 generally calls for the recommendations of BS 5839:Part 1 but also contains its own requirements which may be in variance from the Standard. With regard to existing Fire Alarm Systems the new Standard generally applies to Extensions and Alterations of these system, at least in respects of the Planning, Design, Installation, Commissioning, Maintenance and Certification of the new works. Albeit that the extended/altered system might not, overall, comply with the recommendations of the Standard. 2. CATEGORIES OF SYSTEM BS 5839:Part 1:2002 like the 1988 Standard Categorises Fire Alarm Systems to satisfy one, or both, of two principle objectives… The Protection of Life and The Protection of Property.

The 1988 Standard sub-categorized these objectives into the following levels of protection; Life L1:Automatic Protection Throughout the Premises. L2:Automatic Protection as L3, but also including Defined areas of High Risk. L3:Automatic Protection along Escape Routes and all Rooms opening onto these Escape Routes. M:Manual. (Manual Call Point) Property P1:Automatic Protection Throughout the Premises. P2:Automatic Protection in Defined Areas of High Risk. The new 2002 Standard has recognized and consequently identified the need to expand these categorises further and now include both L4 and L5 in the Life category. L4:Automatic Protection along Escape Routes. L5:Automatic Protection in Defined Areas only. It should be noted that a very comprehensive and recorded record of Risk Assessment should be made if a system is to be designed and categorized as L5 due to the implication and ramifications of a Fire Alarm System being installed for the protection of life with Automatic Detection ONLY COVERING DEFINED AREAS!

P1: All areas covered by Automatic Fire Detection. If Manual Call Points are installed, i.e. Giving the implication, that at times the building will/may be occupied consideration must be given to the provision of adequate Audible Fire Alarm Sounders to warn the occupants of an activation of the Fire Alarm System. All Systems installed for the Protection of Property must have means of remote indicating that the Fire Alarm System has activated. Usually achieved by means of a Digital Communicator or the alike. P2: Defined Areas of High Risk covered by Automatic Fire Detection. Like a P1 System if Manual Call Points are installed, the provision of adequate Audible Fire Alarm Sounders to warn the occupants of an activation of the Fire Alarm System must be installed. Plus the provision of remote signalling. L1: All areas covered by Automatic Fire Detection. L2: As an L3 System. i.e. Automatic Fire Detection on Escape Route, Rooms opening onto Escape Routes, and including Defined Areas of High Risk. L3: Automatic Fire Detection on Escape Routes, Rooms opening onto Escape Routes.

L4: Automatic Fire Detection on Escape Routes. As well as only covering Escape Routes an L4 System does not exclude other Areas of Defined High Risk L5: Automatic Fire Detection covering only defined areas of High Risk. As previously stated a Life System to this category must be subject to a very comprehensive and detailed and recorded Risk Assessment due to the possible ramifications of this type of system. M or Manual. These systems purely rely on possibly the most reliable and effective Fire Detection device for the protection of life in existence! i.e. A Human Being. Consequently this type of system requires the need of Manual Call Point “Break Glass” Units. 3. POSITIONING OF EQUIPMENT There have been no discernable changes in the new standard regarding the spacing and coverage of Automatic Fire Detectors. Smoke Detectors still can cover an overall area of 100 square metres. Heat Detectors like wise with an overall coverage of 50 square metres. The standard it should be noted now recognizes the use of the newly developed CO (Carbon Monoxide) Detectors which it must be said can reduce the causes of false

alarms, however like wise they may not detect a real fire condition, thus it is recommended that they are not used on their own but installed interleaved with optical detection. The only major changes in recommendations for manual call points is the change of distance between call points to 45m. A further recommendation concerns call points located on stairways or landings. To aid in locating the possible area of activation the standards suggest that the call points can either located on the routes/exits leading to the Stairways/landings or on the landings. With either method it is recommended that the units are always connected to the same detection zone of adjacent storey. i.e.

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4. AUDIBLE ALARM SIGNALS The 1988 Standard called for a Minimum Alarm Sound Level of 65dB. The revised 2002 Standard appreciates that a Sound Pressure Level difference of 2 to 3 dB is only just perceivable by the human ear. Consequently the new standard now calls for a general level of 65dB in open areas with a minimum of 60dB at specific points of limited extent within the area. A level of 60dB is now also acceptable in small enclosed spaces such as Cellular Offices, Stairways etc. The requirement of 75dB at a bed-head is required if the intention is to rouse a person from sleep. The new recommended minimum alarm sound levels must still take into account any background noise which is in excess of 60dB with the requirement that the Fire Alarm Audibility Level should be at least 5dB above the Background Noise. The maximum Level of 120dB at any normally accessible point should still not be exceed. If this is not attainable the recommendations require that any Alarm Sounders be supplemented with Visual Alarm Signals, such us Xenon Beacons.

Should the protected premise be used for either Public Entertainment, Retail or Similar in which any background noise may be caused by Music etc. that is greater than 80dB, the new 2002 Standard recommends that in the event of a Alarm Activation the Music and alike be automatically muted by the Fire Alarm System. Both the New and Old Standards recommend that there be at least 2 off individual Alarm Sounder Circuits within the protected premises, even if only 1 sounder was on the second circuit. This recommendation allows that in the event of a Sounder Circuit Failure that at least an alarm sounder would operate to draw the attention of the building occupants to a Fire Condition. Recommendations in the new standard in particular to larger areas accessible to the

general public (typically areas of 4000sq m or more) or where in excess of 500 members of the public are present that the Fire Alarm Sounders within these areas are distributed or interleaved across 2 or more sounder circuits. These individual circuits not being contained within the same common cable sheath. ( i.e. Precluding the use of 4 Core Cable)

5. CONTROL EQUIPMENT BS5839:Part 1:2002 recommends that the Control and Indicating Equipment used for Fire Alarm Systems, including their associated power supplies should confirm to the requirements of EN54 Parts 2 and 4. (Partly due to some recommendation included within the new

BS5839 Standard, both parts 2 and 4 of EN54 are under review.) A fundamental requirement with regard to Fire Alarm Control and Indicating Equipment conforming to EN54 is to limit the number of Automatic Devices (Fire Detectors, Manual Call Points, Interface Units etc.) controlled by a single Micro-Processor within the Control Panel to a Maximum of 512 Devices. This generally limits Single Conventional non-addressable Fire Alarm Panels to 16 Zones (larger panels are generally however made up of one or more interlinking mother boards). This application however, with regards to Addressable Panels limits most single control Panels to 4 Detection Loops. This limitation can be over come with use of “Networked” Indicator Control Panels distributing the Fire Alarm system amongst a number of “SubPanels”, these sub-panels usually being located remote from each other. The practical use of this type of networked system may reduce the cabling for the entire system as the remote panels can be located within specific areas of the buildings, particularly adjacent to the areas to which the connected detection loops are protecting. However there may be some instances, particularly in larger addressable systems

here the use of Networked Systems may not be practical to achieve the desired/required number of detection loops. BS5839:Part 1:2002 being only a guidance document therefore does not preclude the use of Panels that do not confirm with the requirements of EN54. Therefore Multi-Loop Panels manufactured to confirm to the previous standard for panels BS5839:Part 4:1988 can still be used if desired, subject to agreement between the Client and the Designer. This agreed variation must be recorded and noted on the Designers Design Certificate for the system. A major revision to the standard is the requirement for standby power supplies. The 1988 standard related standby capacity to the type and occupancy of the premises protected. The 2002 standard recommends that sufficient backup capacity can now be met by: L Category Systems 24 Hours plus 30 minutes in alarm should suffice. P Category Systems should provide for any unoccupied time of the protected premise plus 24 hours up to a maximum of 72 hours plus 30 minutes in alarm. Should the 72 hour period expire and fault signal should be sent to the connected remote monitoring centre.

6. CABLING Unlike the earlier standard where the use of Non-Fire Rated Cabling would have been acceptable for the Detection Circuits and Fire Rated Cables used for the Alarm Circuits. The 2002 standard recommends the use of Fire Rated Cables for Critical Signal Paths, this includes both the Detection and Alarm Circuits. Even though the Indicating and Control Equipment is provided with means of a “Standby Supply” (i.e. Battery Backup) the normal Electrical Mains Supply to the equipment is now considered as a Critical Circuit and consequently should be adequately protected from the effects of fire. Cabling for Critical Signal Paths are now categorized to two standards; Standard Grade Fire Resisting Cables, generally of the Soft Skinned type, FP200/Firetuf and the similar. Enhanced Grade Until recently only M.I.C.C. Cable, but now includes both FP200 Plus & Firetuf Plus Soft Skinned cables Standard Cabling in most instances will usually be adequate for a great majority of installations. Detection, Alarm Circuits etc.

Apart form the previously mentioned FP200 and FireTuf, Fire Rated Steel Wired Armoured cable would also be acceptable particularly for external applications. Where a buildings Fire Alarm System incorporates a four or more phased evacuation procedure, or the building is greater than 30metres in height, or being identified by a Fire Risk Assessment or as part of a Fire Engineered solution which compensates for shortfalls in building construction than the use of Enhanced cabling should be used. The standard recommends the use of Enhanced Grade cabling for Network Communication Cables between networked Panels. However if all the following criteria can be met standard Grade and Communications Cables (i.e. Beldon Type Cables etc.) would be acceptable; 1. The Network is configured as a loop; and 2. There is diverse routing of both the incoming and out going circuits of the Network Loop; and 3. There will be no loss of communication to any sub-panel in the event of a single open or short circuit on the Network Loop.

7. REMOTE MONITORING BS 5839:Part 1:2002 has identified possible inherent faults with the current methods of providing Fire Alarm Activations to Remote Monitoring Centres by means of Digital Communicators and consequently provides the recommendations to alleviate the short comings of current equipment; All interconnections including the telephone line should be monitored (usually only achievable by means of BT Redcare or similar). Interconnecting cables to be run through areas of low Fire Risk. Digital communicator Unit located within area of low Fire Risk or protected by means of Automatic Fire Detection. Standby Capacity of any communicator should match that as of the

Fire Alarm System and should be a minimum of 24 hours. Which would preclude the use of security Digital Communicators which only usually have a backup capacity of 8 hours. 8. FIRE ALARM SYSTEM DESIGN BS5839:Part 1:2002 has identified, in particular for new Fire Alarm Systems the need to manage and limit the numbers of false alarms. Consequently the revised/updated standard recommends and emphasizes for a more detailed roll and resultant responsibility for the designer of new Fire Alarm System. The standard as previously stated does not identify the need for a fire alarm system. This is the responsibility of the purchaser, be they a Developer or Final User of a building. This process will evolve consultation with the Fire Authorities, Building Control Officers and Insurers. The decision/consultation process for new buildings would progress through and with reference to general compliance to; FIRE PRECAUTIONS ACT (1971) BUILDING REGULATION Which would identify and provide solutions to enable the building to be issued with the necessary resultant Fire Certificate. From this point and for existing buildings this decision/consultation

process would continue with reference to the "WORK PLACE REGULATIONS" and the resultant RISK ASSESSMENT would identify the need (if any) for the provision of a Fire Alarm System.

Upon completion of the decision process the purchaser should be in procession of all the necessary information to identify the need and category for a fire alarm system. This information should then be passed to the Designer whom, with regard to the identified Risk and Category of System, provide a suitable design inline with the recommendation of the new standard. The ultimate responsibility for the need and category of the system solely rest with the purchaser. However the designer can propose a category should the situation arise. But

the final decision must be taken by the client/purchaser. The proposed new Fire Alarm System must take into account all the findings of the provided Risk Assessment which has identified the category of the new system. Vital importance in the design is the need to identify and resolve/eliminate any potential causes of false alarms. Any variations from the standard should be agreed between the Designer and the Purchaser. These if agreed variations should be documented. Upon completion of the design a signed DESIGN CERTIFICATE would be submitted detailing all aspects of the final design including any agreed variations from the standard. This Certificate will form an integral part of the proposed system and must be forwarded through the entire process from the installation, commissioning and final acceptance by the purchaser. 9. INSTALLATION BS 5839:Part 1:2002 in keeping with the recommendation about responsibilities for both the Purchaser/Client/User as well as the system Designer has also identified the need for the Competency and subsequent responsibilities for both the Installation and Commissioning Engineers. The installation engineer(s) responsibility extends to ensuring that they, as well as any

sub-contracts they use carry out the installation in compliance to both the new standard and the designers design. They also have a responsibility to make the designer aware of any building features that the designer was not or could not have known which would effect the design. They should not however alter the design with out written confirmation from the designer. The installers responsibility also extends to ensuring compliance for installed components to both manufactures and the British Standards recommendations. Consequently any installer engaged in the installation of fire alarm systems should be fully conversant with BS 5839:part 1:2002. The installation and in particular the cabling should be installed to the requirements of BS 7671 (Wiring Regulations) Fixing of cables should be as per the manufactures requirement, generally ensuring that Metal Fixings are used where necessary (i.e. Stainless Steel Cable ties when securing below steel cable trays). Particular attention should be made to the use of metal fixing within PVC Trunking, where the trunking forms the only means of support for the Fire Alarm Cabling installed within. Cabling installed should meet either Standard or Enhanced Grade dependent on both the

designers specification and the probable intended routing of the cables as well as any system and cabling requirements regarding Earth/Screening continuity as required by the manufacture. As with any electrical or mechanical installation protection and fire stopping should always be considered. As per BS 7671 (Wiring Regulations) all the cabling should be tested for insulation resistance. BS 5839:Part 1:2002 recommends that these test should always be carried out to prevent damage to equipment with all equipment disconnect. Also it is recommended (which may be at variance with the wiring regulations) that thes test be carried out using a Test Instrument set at 500v. The standard also calls for the mains supply to the Indicator and Control Equipment and any other relevant supplies associated with the Fire Alarm System should be tested for both Earth Continuity and Earth Fault Loop Impedance. The field wiring and most particularly Loop Wiring to be tested for Circuit Resistance. All these test must be recorded for the system final documentation plus a copy of the results must also be forwarded to the commissioning engineer.

Once the installation and test are completed the installation engineer would sign of the system and provide the next Certificate for the system, the Installation Certificate. 10. COMMISSIONING Once the Fire Alarm System has been installed the system should be set-up and functionally tested, the commission. Like the installer the Commissioning Engineer should be competent with a good knowledge of Fire Alarm Design, False Alarms and their Avoidance and Fire Alarm Installation. The engineer should be able to deal directly with the purchaser/client and other interested parties. To facilitate the commissioning all documentation for the Fire Alarm System, System Specification, Design Documents (including a copy of the Final Design Certificate), consultation documents, Original and the Installers “As Fitted” Drawings and the installers Test Records must be made available to the Commission Engineer. Apart from carrying out any programming of any addressable Fire Alarm Panels, the commissioning engineer must ensure that the system is fully functionally tested. Call points, Automatic Detectors, Interfaces etc. operate and indicate correctly, audibility levels should be measured for sounders and where Voice Alarms are installed their

intelligibility is satisfactory. Signals required to be transmitted to “Alarm Receiving Centres” are correctly received. Cause and Effects of the system are functionally checked and operate as per the specification. They should also note any changes to the building since the original design that may effect the design and performance of the system. The engineer would also check that the installed components, Manual Call Points, Detectors, Control and Indicating Equipment, Visual Alarms are suitable and correctly sited and consequently acceptable to the relevant clauses of the British Standard. Also recommend by the standard and to be checked by the Commission Engineer is that a suitable Zone Plan is displayed. During the commission the engineer would also inspect and check the suitability of the Mains Supply, Standby Power (i.e. Battery Backup) functions correctly both on and off load and has sufficient backup capacity. There is also a recommendation that the batteries are labelled with the date of installation. The engineer would also check that the correct/specified cable has been installed (as as far as it is reasonably practical to ascertain), as well as the workmanship of the installation. As far as reasonably practical to ascertain the engineer would also check for immunity to

false alarms. Any non-compliances with the design should be noted and the designer informed. Upon satisfactory completion of the system commissioning following a "SOAK TEST" (during which time the system would be deemed as not operational) the system would be signed off by the engineer and a Commissioning Certificate submitted. Like both the Design and Installation Certificates all details pursuant to the Design including any agreed variations from the new standard would be noted on the Commission Certificate, all of which should be consistent through all the Certificates. 11. FIRE ALARM SYSTEM ACCEPTANCE The final stage of the installation process, not taking into account the necessary ongoing maintenance of the system would be the handover of the system to the purchaser/client/user. Arrangements for the handover should include for full training to the "Users Responsible Person" on the operation of the system and the provision of full documentation for the system. Including all the original consultation documents, design documentation, “As Fitted” installation drawings, a system Log Book, Maintenance Instructions and the Design, Installation and Commissioning Certificates to

be handed to the purchaser/client/user. Once the purchaser/client/user has formally accepted the Fire Alarm System they will sign the Final Acceptance Certificate as evidence of their satisfaction of the system. It should be noted that the new standard has a strong recommendation that a minimum and this duration may/should be increased for larger systems that the new system be left on a “Soak Test” for at least a week before the system is certified as being functional and can consequently be formally handed over to the purchaser/client/user. 12. FIRE ALARM SYSTEM MAINTENANCE BS 5839:Part 1:2002 provides recommendations and consequently suggested procedures regarding the Maintenance/Servicing of Fire Alarm Systems. The new Standard recognizes that modern Fire Alarm Systems may incorporate a high degree of monitoring, so that any faults that develop are indicated automatically, usually on the Control and Indicating Equipment. These fault indications are only effective if they are identified and appropriate action taken. Consequently a need has been identified that the monitoring of these systems should be carried out by the Fire Alarm System Users nominated Responsible Person, this person

should be some one whom is normally employed within the protected premises. The Responsible Person shall ensure that Routine Tests of the Fire Alarm System are carried out. Every week, a Manual Call Point should be operated during normal working hours, it should be confirmed that the Control Equipment functions correctly, Alarm Sounders Sound and should a link to a Remote Monitoring Centre be connected that a signal is correctly received. The weekly test should be carried out at approximately the same time each week with the alarm sounders not operating for longer than 1 minute. A different Call point should be tested each week so over a period all points are tested. (i.e. 80 Call Points would take 80weeks to test) Premises provided with means of Standby Power Supplies (Generator) should be test Monthly by simulating failure of the normal power supply. As previous identified provision of a Fire Alarm System both new buildings would be subject to a consultation process with reference to: Fire Precaution Act Building Regulations and as well for both new and existing buildings: Work Place Regulations resultant Risk Assessment

The Fire Precautions (Workplace) Regulations require that any equipment and devices provided in respect of the regulations SHALL be subject to a suitable system of maintenance and be maintained in an efficient state, in efficient working order and in good repair. Failure to provide this may warrant the user liable for prosecution. The Health & Safety (Safety Signs & Signals) Regulations 1996 requires that Fire Alarm warning system must be provided with a guaranteed emergency supply in event of interruption of the normal mains supply, unless the hazard has thereby been eliminated. Consequently systems not having a standby power supply (i.e. Battery Backup) are no longer legal! BS5839:Part 1:2002 recommends that maintenance of Fire Alarm Systems be carried out by Competent Persons (i.e. Maintenance Organisations). A Periodic Service Inspections of a period not exceeding six months, subject to a Risk Assessment and agreement between all interested parties this period may be reduced. Tests and Checks should include operation of one Manual Call Point or Detector on each Circuit, changes that may effect the operation of the system, signals if connected to Remote Monitoring Centre. An annual inspection (over a 12month period) to include a complete

function and operational test of all equipment connected and interfaced to the Fire Alarm System, including all “Cause and Effects”. Upon satisfactory completion of the Inspection; All Devices operated correctly Transmission to Remote Monitoring Centre correctly received Analogue Levels on Addressable Equipment within acceptable range Radio Signal Strength for Radio Equipment within acceptable range Cause & Effect programme proved Standby Power Supply Capacity Satisfactory a Inspection and Service Certificate would be issued with any recommendations noted. During the annual inspection confirmation of the number of false alarms would be checked in the Log Book to see if within acceptable limits.