Presentation on theme: "FIRE DETECTION AND ALARM SYSTEMS for Lancashire County Council."— Presentation transcript:
1 FIRE DETECTION AND ALARM SYSTEMS for Lancashire County Council. Presented byMike TurnerECA Fire and Security Sector
2 AGENDA UNDERSTANDING OF: Changes to BS5839 pt 1 :2002 Cable grades and requirementsDetection selectionDetector coverageDifferences between Non addressable and AddressableEN54 / BSFalse alarm managementMains fire AlarmsWarning for people with impaired hearing and sightCertification for:Design, Installation, Commissioning and Maintenance
4 CATEGORIESCategories previously known as TypesDesigner alone can not select CategoriesRisk AssessmentEnd userbuilding Control / Fire OfficerDesignerInsurance
5 CATEGORIES M and L1 to L4 (Previously known as Types) Activation methodAlarm devicesMMCPThroughoutL4MCP + AFD on escape routes onlyL3MCP + AFD on escape routes AFD in rooms opening onto*L2MCP + AFD as L3 + specified areasL1MCP + AFD throughoutCategories, clause 5, (previously Types)M comprises manual call points where recommended and alarms throughout the building. No AFD.L4 could be regarded as “enhanced M”. L4 might be agreed as a result of a risk assessment and consultation with the fire authorities.In Category L3 and L4 systems, smoke detectors, or a mixture of smoke and combustion gas detectors, should be provided in the following: — all escape stairways; — all corridors; — any other areas that form part of the common escape routes. NOTE Main access and egress stairways normally form part of escape routes, and should be treated as escape stairways.The objective with Category L3 or L2 systems is to enable all occupants, other than possibly those in the room of fire origin, to escape safely, before the escape routes are impassable owing to the presence of fire, smoke or toxic gases.*L3: In Category L3 systems, heat, smoke or combustion gas detectors should be installed in all rooms that open onto the escape routes, except that rooms opening onto corridors of less than four metres in length need not be protected, provided that fire resisting construction, including fire doors separates these corridors from any other section of the escape routes, see clause 8.2 d).In a Category L2 system, the rooms or areas protected should comply with the recommendations for a Category L3 system, but, in addition, automatic fire detectors should be installed in rooms in which the fire risk (see definition 3.23) is high enough to warrant individual protection. NOTE Any reference to a Category L2 system (e.g. in a specification, proposal or submission to an enforcing authority) should clearly identify the rooms or areas in which these additional detectors are to be installed and should identify the type of detector required (e.g. heat, smoke or combustion gas).L1: The intention with a Category L1 system is to protect the lives of all the occupants in a building including those in the room where a fire might start. For this reason smoke detectors would be used in bedrooms to comply with Category L1, (see clause 8.1.2)AFD on escape routes should be optical smoke detection or CO mix
6 CATEGORY L5 –Fire safety engineering Activation methodAlarm devicesL5AFD where specifiedThroughoutL5/MAFD where specified + MCPFor category L5, the person or organisation doing the risk assessment takes on the legal responsibilityThis requires serious design ability, risk assessment procedures, knowledge of fire safety engineering, professional indemnity insuranceComplying with the recommendations for category L3, for example, is relatively straightforward and in the event of a claim, responsibility may ultimately reside with BSI.Responsibility for L5To take on this properly would require personnel with detailed design ability, competence in risk assessment procedures and knowledge of fire safety engineering (usually a 3 year university degree course). The organisation should have professional indemnity insurance (PII) and cover for legal risk.See Annex A for guidance on the choice of appropriate category of fire detection and alarm system.For detailed recommendations on fire precautions in buildings, including the likely need for fire detection and alarm systems, detailed advice is given in BS For advice on fire engineering solutions, reference can be made to BS 7974 and PDPrescriptive Categories Most organisations will specify and use one of the prescriptive categories such as M, L4, L3 etc., to avoid taking on the responsibility of risk assessment and fire safety engineering. However it should be remembered that making the initial choice of category is a responsibility in itself and should not be taken lightly. The sales engineer or designer should not be expected to make this decision in isolation – the client / owner / employer / insurer / may also be part of the decision and consultation process.
7 CATEGORIES P1 and P2 Cat Activation method Alarm devices P1 AFD throughoutWhere requiredP1/MAFD throughout + MThroughoutP2AFD where specifiedP2/MAFD where specified + MIn a Category L1 or P1 system, automatic fire detectors should be installed in all rooms and areas of the building, but the following rooms or areas need not be protected if they are of low fire risk:— toilets, shower rooms and bathrooms;.— stairway and toilet lobbies;— small cupboards (typically, less than 1 sq m);— some shallow voids (less than 800 mm in depth).NOTES In some public buildings, such as hospitals and shopping centres, toilets might not be of low fire risk, owing to the potential for arson. A risk assessment should be done in this case.A riser in which there is a fire resisting floor may be treated as a cupboard.(see clause 8.2 f))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 of smoke and hot gases in, at least, the early stages of fire. It is not the job of the fire detection and alarm designer to suggest design changes for the building, but to fit the fire alarm system into the existing physical barriers.
8 COMMUNICATIONS WITH THE FIRE SERVICE Designer to ascertain if automatic comms requiredFor Cat P, Communications recommended unless continuously occupiedBS 5979 for ARCCommunication unit to be protected by AFDCommunication cables routed through:Areas of low fire risk; ORAreas protected by AFD or extinguishing; ORUsing fire resistant cablesCommunications with fire service, clause 15 The Designer should ascertain if automatic communications with the fire service are required. If automatic communications are not required (e.g. for a Category L system), then a quiet area away from the alarms may be required for someone to dial in an emergency (a momentary silence switch for local alarms in that room or visual alarms may be acceptable).For Category P, Automatic Communications are recommended unless continuously occupied (i.e. 24h 7day).For multi occupancy (e.g. several tenants in a building) automatic communications is recommended.BS 5979 is the relevant standard for an Alarm Receiving Centre (ARC).Using a connection to an ARC including fault transmission can keep battery sizes to acceptable limits where the building is unoccupied for long periods of time (e.g. Easter holiday Thursday evening to Tuesday morning).AFD is recommended for the room where the Automatic Communication equipment is located.Any interconnection cable from the cie to the Automatic Communication equipment should be monitored.The power supply for the Automatic Communication equipment should have the same standby duration capability as the cie.Cables in the building associated with Auto Communication should be routed through one of the following:a) Areas of low fire risk; or b) Areas protected by AFD or an automatic fire suppression system; or c) Using fire resistant cables from the fire alarm cie to the auto transmission equipment and on to the exterior of the building. Note: When outside the building cable routing or type is not critical for fire protection reasons, but the usual telecom requirements apply.
9 SITING THE Control and Indicating Equipment Consult user / fire authoritiesNear entrance – repeaters may be required at other entrances – consultationAdequate light – normal and emergencyLow ambient noise – fault buzzerLow fire hazardAFD – unless continually occupied or negligible fire hazardAccessible for servicing if necessary.Siting the Control and Indicating Equipment (cie), clause 23In residential and certain other premises the panel should be easily accessible to staff, but not a temptation to residents.When the brigade enter the premises they may want to examine the panel to ascertain the extent of the fire. The panel should therefore preferably be on the ground floor near to an entrance used by the brigade. If the panel has to be sited in a fire control centre, remote from an entrance, then functional repeaters may be installed at the entrance(s).Emergency lighting will be required near to the panel(s) to illuminate the controls. If not on an escape route the floor of the room in the vicinity of the panel should be illuminated to 5 lux (ref BS5266 pt ).The area should be quiet enough to enable the control sounder (fault buzzer) to be heard.It is important that the panel is positioned in an area of low fire risk, so that the alarms are sounding before the fire affects the panel. Automatic detectors should be positioned near to and in the same room as the panel, unless the room is continually occupied such as a security office, or the content of the room comprises a negligible fire hazard.
10 VARIATIONS from BS 5839-1 Variations were previously deviations Not an excuse for ignoring non-compliances to BSMost jobs will not need variationsVariations apply to intentional and appropriate aspects, following a risk assessmentFeatures found by installer not known to designer should be documented for action / agreementAll variations to be agreed with interested partiesowner/user/client/insurer/fire authorityVariations, clause 7Variations were previously Deviations which implied shortcomings. Variations from the recommendations to BS apply to intentional and appropriate aspects, e.g. :-area of zone slightly increased due to size of buildingdBA target slightly reduced due to very quiet area such as a libraryA variation should not be introduced because certain cover was forgotten or overlooked. There should be an engineering justification for a variation.Features that the designer was not aware of, but noticed by the installer or commissioning engineer should be documented for later action / agreement. The feature (e.g. obstruction or partition) may require additional detection or alarms after consultation with the interested parties. All interested parties (e.g. the fire authorities) should be involved in the consultation process to agree any variations.Some variations can arise from a fire risk assessment, in which it is determined, for example, that an area of the building may be unprotected by automatic fire detection, albeit that, in the Category of system otherwise deemed necessary, protection is recommended in BSOther variations may be based on the engineering judgement of a competent person, who might, for example, consider that the extent of protection disabled in the event of a single cable fault can slightly exceed the limitations recommended in this standard, without any significant decrease in the integrity of the system.Documentation should show the parties consulted in agreeing the variation and its justification.
11 MCP ZONES - LANDINGSZone 2Zone 3Z4Z5Zone 1Z1Z2Z3EITHERORPREFERABLEMCP in accommodation zone, not in stairway zone, at that level (in main area or on landing)Detection Zones with MCPs, clauseThe zones for a category M are less critical because someone may operate a call point away from the fire. To try and make the operation of a call point more indicative of where the fire has started, the MCPs on stairway landings should be wired into the zone for that storey. This shows options for where to place the MCP. Wherever it is placed physically, it should be in the same zone as the accommodation area. BFPSA advice is to fit the MCP both physically and zonally in the accommodation area. This will match requirements for phased evacuation in clause 19. For an MCP at the final exit at the bottom of a stairway, the allocation of zone should be consistent with the remainder of MCP in that stairway.
12 MANUAL CALL POINTS BS EN 54-11, single action, RED Breaking frangible element operates switchAll the call points must be similardo not mix hammer and thumb push typesUse plastic element (not glass) in food prep areas if requested (consultation)If necessary, use drip proof, waterproof or hazardous area typesSome shops do not have public call pointsManual call points, clause 20Manual call points should be red to comply with BS EN The call point is possibly the simplest and most easily understood device in a fire alarm system, but arguably the most important.The frangible element is often glass protected with a plastic film.When operated a switch mechanism is released and this raises the alarm.Some older style call points required a hammer to break the glass, modern types need thumb pressure. Do not mix the types in an installation.Food preparation areas usually do not allow the possibility of broken glass nearby, so use plastic types of elements.Weatherproof and waterproof types are available for outdoor areas.In hazardous areas with flammable gas or explosive dust, if using an approved IS barrier it is not usually necessary to use explosion proof types of MCP. However advice should be sought for IS and flameproof devices if designing a system for use in an explosive atmosphere.For fully manned shops or certain other premises where there is the possibility of malicious operation, the public may not have access to call points, but the staff have concealed call points. This prevents malicious operation. This is always decided in consultation with the fire authorities and subject to a Variation. The decision is not the responsibility of the designer.
13 SITING manual call points Final exit to open airLandingStairway1.4mExit15mm projectionEscape routeUp to 90mMCPs should be located on escape routes and, in particular, at all storey exits and all exits to open air (whether or not the exits are specifically designated as fire exits), so that it is impossible to leave the storey or the building without passing a manual call point.In multi-storey buildings with phased evacuation, in which only a limited number of floors are evacuated at one time, MCPs should be located on the accommodation side (not located on stairway landings), because persons travelling down the stairway might operate a manual call point several floors below that on which a fire is located, resulting in evacuation of inappropriate areas.Mounting height: 1.4m +/- 0.2m above floor level.Call points should project by 15mm (i.e not flush), this allows search and find when view from the side.See also slide 42 for call points on the accommodation side of landings.
14 SITING manual call points Paint booth45m30mTravel distance up to 45mStairwayDistribution of MCPs should be such that no one need travel more than 45 m to reach the nearest MCP, measured along the route that a person would actually follow taking into account the layout of walls, partitions and fittings. If, at the design stage, the final layout of the premises in unknown, the maximum straight line distance of 30m between any point in the building and the nearest manual call point applies; after final fit-out of the premises, the limit of 45 m should still then apply.NOTE These distances are arbitrary, but reflect the maximum acceptable distances between any point and the nearest storey exit commonly applied to any premises.Near any high risks or special hazards (e.g. kitchens or cellulose paint spraying), a manual call point should be sited in close proximity. For special hazards, the maximum straight line distance should be 16m, or the actual travel distance allowing for fit-out in the premises should be a maximum of 25m.NOTE In both examples given above other considerations also apply. Kitchens or food preparation areas may require the use of a non-glass frangible element to avoid the possibility of food contamination with glass fragments. The spraying area might require the use of equipment certified for use in potentially explosive atmospheres (see clause 10). Manual call points with non-glass frangible elements should comply with the requirements of BS ENTEST D
15 ALARM warning devices Large qty of low power, not small qty high power 125dBALarge qty of low power, not small qty high power65dBA generally, or 5dBA above ambient noise (30s)75dBA to awake at bed head120dBA max500 TO 1000Hz20 to 30dBA loss at doors20dBA30dBA95dBAAlarms, clause 16Care should be taken when designing to these figures not to use a small number of very powerful sounders as these may cause an adverse reaction in an emergency. It is therefore better to use a number of low powered sounders, if necessary, individually in each room. Specifically designed bedroom sounders and detector base sounders are available for this purpose.Alarms, whether sounders or bells, should be arranged to provide 65dBA in general areas, where the ambient noise is no more than 60dBA. If this is exceeded for more than 30s, then the alarm sounders should be increased so as to exceed the ambient noise by 5dBA.NOTE This recommendation does not apply to noise created by running water in bathrooms and shower rooms.For sleeping risk areas, sounders should be arranged to provide 75dBA at the bed head to awake a sleeping person.Damage to hearing may occur above 120dBA, so it is better to avoid over-powerful sounders in a small space.The frequency of sounders should be 500 to 1000Hz. Most sounders, intended for fire alarm use, operate in the region of 800 to 1000Hz.Sound passes through a door with a loss of about 20dBA and through a fire door with a loss of about 30dBA.For environments where alarms may not be heard visual alarms or strobes may be necessary in addition.Further details on alarm sounders and dBA calculations are included in BFPSA Training UNIT 3, Advanced Sounder Design.85dBA
16 ALARMS 65dBA is the general recommendation 65dBA CORE AREA,IGNORE 0.5m BORDERROOM65dBA is the general recommendation2 or 3dBA is not noticeable to the human earMay be relaxed to 60dBA:stairways, offices up 60sq m, limited pointsSimilar sounds, i.e. not mixing bells/soundersAlarm requirements and relaxations65dBA is the general recommendationBS (2002) recognises that 2 or 3dBA is not noticeable to the human ear.Consequently a pragmatic view is taken and if some specific points of limited extent, enclosures up to 60sq m (e.g. small cellular offices) or stairways reach only 60dBA, this would be regarded as acceptable.The premises should only use one type of sounder, i.e. bells and sounders should not be mixed.Core area measurements In carrying out measurements to verify compliance with the recommendations, account need not be taken of sound pressure levels within 500 mm of any walls or partitions.No relaxation for 75dBA None of the relaxations above apply in the case of the 75dBA recommendation to awake a sleeping person.
17 VISUAL ALARMSVisual alarms if ambient noise more than 90dBA, or ear protection is wornReadily visible, different from other visual indicators30 to 100 flashes per minutePreferably red light flashAttracts attention, but not glare, min 2.1m Height and no closer than 150mm to ceiling2.1m min height150mm minVisual alarms, clause 17Visual alarms should be used where there is a high ambient noise (90dBA) or people are wearing hearing protection.Visual alarms should be sufficient in quantity and bright enough in the normal ambient lighting to be noticed.The flash rate recommended is 30 to 100 per minute. Most visual alarms available flash at about 60 per minute.The colour recommended is “preferably” red, so if another facility has visual alarms that happen to be red, then choosing a different colour for the fire alarms would be acceptable. Note that this refers to the colour of the light output, not the colour of the housing.If the visual alarm is too low it may not be seen, 2.1m is recommended as the minimum mounting height, but most applications would be higher than this. The visual alarm may not be as effective to close to the ceiling, so a mounting distance of at least 150mm from the ceiling is recommended.Alarms for people with impaired hearing, clause 18Visual alarm signals provided for people with impaired hearing should comply with clause 17. The visual alarm devices should be regarded as fire alarm devices for the purpose of this standard and, for example, circuits serving the devices should be monitored and protected against fire accordingly.Tactile alarm devices provided for people with impaired hearing may be fixed, moveable or portable. The intensity of output of tactile alarm devices should be sufficient to attract attention. Approval of devices for people with impaired hearing would be the subject of consultation with the users.
18 FIRE ALARMS DEVICES Meeting rooms, 60dBA Bedrooms, 75dBA general quiet offices, greater than 60sq m area, 65dBALimited area 60dBA minPress shop, 95dBA noise, 65dBA + VISUALMachine shop, 78dBA noise, 83dBAStairs, 60dBAExternal audio/visual for Category P
20 WIRING: fire resistance All cables for critical signal paths and mains supply should be fire resistant for 30 minuets(Fire shock and water spray resistant tests)Specification for cable performance Clause 26.2.dGRADES OF FIRE RESISTANT CABLEMost premises – Standard grade, BS 7629soft skinned (modified plastic cable)Higher risk – Enhanced grade, MI or equivalent30m high, long evacuation or 4 stage evacuationor as required by risk assessmentLCC stipulate MICC for all InstallationsWiring, clause 26 The basic rules of wiring are:All cables for critical signal paths and mains supply (final circuit) should resist the effects of fire for 30 minutes. These effects include fire, shock and water spray.Surface plastic or metal conduit does not improve cable fire resistance.Fire resistance for cables can be achieved using mineral insulated cable or certain pliable cables (“soft skinned”).The specification for cable fire performance is given BS (2002) clause 26.2 d). Tests are applied to one sample of cable.THERE ARE TWO GRADES OF FIRE RESISTANT CABLE:Standard grade. This may be soft skinned cable (including steel wire armoured fire resistant cable) and this will be adequate for the great majority of installations.Enhanced grade. Mineral Insulated Copper Clad cable would pass the test for enhanced grade. There may also be other cables that pass this test. This cable is recommended for any of the following:1. Phased evacuation with 4 or more stages for unsprinklered buildings2. Unsprinklered buildings greater than 30m high3. Where evacuation is, in part, delayed and critical signal cables pass through areas at risk of fire4. Where a risk assessment identifies a need for enhanced cable.Note: Fire retardant or low smoke and fume cable may not be fire resistant grade.Further details on cables and cable calculations are included in BFPSA Training UNIT 3, Advanced Design.
21 WIRING: requirements Mechanical protection – Below 2m 1sq mm minimum MI or steel wire armoured self protected1sq mm minimumSegregation from other services for EMCSame colour cable throughout – red preferredIntegrity not compromised by fixings or jointsjoints minimisedjunction boxes labelled “fire alarm”Mechanical protectionWhere exposed cables are below 2m and vulnerable to mechanical damage “particular consideration” should be given to protection. MI and steel wire armoured is considered to be mechanically robust not to need further protection, except in very arduous environments. Other cables can be mechanically protected with plastic / metal trunking or conduit.Conductor sizes should be not less than 1sq mm.EMC is very important in fire alarm installations. Cables should be segregated from other services according to guidance from the manufacturer’s.The colour of fire alarm cable should differentiate it from other cables in the building. Red is the preferred colour.Integrity should be similar throughout (with the possible exception of internally in the devices, interfaces and cie) with preferably no joints or minimal joints and with fixings likely to withstand fire with similar integrity to the cable. Metal cable fixings would comply with this recommendation [ref clause 26.2 e) and f)].
23 TYPES OF FIRE DETECTOR Heat Smoke Combustion gas, CO Flame Point, fixed, rate of riseLinear heat sensing cableSmokePoint, ionisation, opticalLinear optical beamAspirating, sampling points – holes in pipeVideo, image processingCombustion gas, COIncomplete combustion, not smoke detectionFlameInfra-redUltra-violetMulti-sensore.g. heat and optical smokeTypes of fire detector, clause 21.Fire detectors are designed to detect one or more of the four characteristics of fire, namely:— heat;— smoke;— combustion gas (such as carbon monoxide);— infra-red or ultraviolet radiation.All these will be covered in the following slides.Smoke may also be detected by video techniques, in which closed circuit television cameras monitor the protected space; the signals from each camera are analysed electronically to detect the presence of smoke by the obscuration of part of the camera’s field of view that it creates. Detection therefore relies on illumination of the field of view by normal lighting or specially installed infra-red light sources. Such systems are still in their infancy at the time of publication of BS (2002). They are used for special applications and require specialist design.
24 Prot life where fire starts EXAMPLE DETECTOR CHOICESEscape routesRooms opening ontoProt life where fire startsLiquid fuel storeCategoryL1L3-4L3Heat pt. fixed Heat pt. RoR Heat linearOPOptical pointIonisation pointOptical beamCOmixAspiratingFlameFor Category L1 systems, in rooms in which there is a need for automatic detection of fire in order to protect the occupants of these rooms, smoke or combustion gas detectors should to be provided. In other rooms, heat detectors might be acceptable (ref clause 8.1.2). For Category L3 systems, protection can be achieved in rooms opening onto escape routes using sprinklers, provided that the sprinkler system automatically initiates a fire alarm signal via the fire alarm system, on flow of water from a single sprinkler head. See also slide 8 and clause 22.3 e) Note. Multi-sensor fire detectors including optical smoke detection as one of the elements, could be used where optical smoke detectors are shown (ticked). Flame detectors are not suitable as the sole means of detection in a room opening onto an escape route. If flame detection (or any detector other than heat, smoke, CO or sprinkler as above) is used to cover a particular risk in a room opening onto an escape route, then it should in addition to heat, smoke, CO detection, or sprinkler as above. Optical Detectors and CO detectors (mix) in escape routes BS clause d) recommends that where smoke detectors are used on escape routes they should be the optical type. Clause 8.2 recommends that smoke detectors or a mixture of smoke and CO detectors should be used. This means that escape routes may be protected with: a) optical smoke detectors only OR, b) a mixture of optical smoke and CO detectors, but the ratio is not stated (for example, 3 optical to 1 CO or 1 optical to 1 CO). NOTE. CO detectors only on an escape route are not recommended.
25 CHOICE OF FIRE DETECTION Speed – To suit fire hazard – min false alarmsHeat – alcohol fire - good immunity to false alarms, easy maintenance, RoR most sensitiveIonisation smoke – small invisible particlesOpt smoke – visible smoke, escape routesMulti-sensor fire detectorFlame – specialist e.g. atria, range see manf. datafixedRoRT deg Cfixed heat det thresholds807060No one type of detector is the most suitable for all applications. Final choice will depend primarily on: — the speed of response required (to satisfy the fire safety objective); — the nature of the fire hazard; — the need to minimize false alarms (e.g. multi-sensor fire detectors may be considered). However, other factors, such as cost, suitability for the environment and maintenance requirements might need to be considered. All fire detectors will respond to some extent to phenomena other than fire. Heat detectors , clause Heat detectors may take the form of either point type detectors or line type detectors. The detection system may be designed to respond when a fixed temperature is reached. The heat detector may also include a sensor that responds to the rate of rise of temperature. In this case the detector responds when either the temperature rises at more than a certain rate, or when the fixed temperature is reached. Heat detectors complying with BS EN 54-5 operate in the manner described above. Smoke detectors, clause Point smoke detectors utilize one (or both) of two principles: a) Ionization chamber smoke detectors detect small particles of smoke, or invisible products of fire, by the reduction it causes in the current that flows between electrodes in an ionization chamber within the detector. Ionization detectors are sensitive to invisible products such as cooking fumes and, to avoid false alarms, should not be used near cooking facilities. b) Optical smoke detectors detect smoke by means of a small light source within the chamber. If smoke enters the chamber the light scatter from the smoke particles can be detected. Optical detectors detect visible smoke. For this reason they are used on escape routes where it is important that fire is detected before the escape route becomes impassable due to (visible) smoke. Multi-sensor fire detectors, Multi-sensor fire detectors contains more than one sensor, e.g. heat and smoke sensors. The purpose of combining sensors in this way is to enhance the performance of the system in detection of fire, or its resistance to at least certain categories of false alarm, or both. Signals from the internal sensors may be combined for potential reduction of many types of false alarm. With some multi-sensor fire detectors it is possible to disable an individual detection sensor. This might be used in a time related system to reduce false alarms. For example, with a heat and optical multi-sensor detector the optical sensor might be disabled during the day. If this is the case it is vital that the detectors are spaced for the least sensitive sensor, in this case, heat. Flame detectors, clause Flame detectors detect the infra-red and/or ultraviolet radiation that is emitted by flame. Both types use radiation-sensitive cells that “see” the fire either directly or through built-in lenses or reflectors. Infra-red flame detectors are usually designed to respond to flame characteristics such as flicker, size or more than one specific radiation frequency. Types intended for outdoor use might be designed to respond to specific infra-red frequency bands that are not characteristic of solar radiation. Ultraviolet flame detectors normally operate within wavelengths that the ozone layer filters out of solar radiation. Hence, ultraviolet detectors do not normally respond to sunlight and may generally be used outdoors.
26 ASPIRATING SMOKE DETECTION ...it actively draws a continuous air sample through a sampling pipe networkSampling PipesEndSamplingCapPipesAtmosfireAir Samples
27 CHOICE OF FIRE DETECTION Opt beam – large areas, high levelAspirating – aesthetics, high level, vert pipesTxRxTx/RxreflectorOptical beamAspirating detectorX Sampling points (holes)Optical beam smoke detectors are effectively line type smoke detectors. They comprise a light source (usually operating at infra-red frequencies) and a receiver. The two are either separate units or housed within a single unit, in which case reflectors are used to reflect light from the transmitter back to the associated receiver. Optical beam detectors operate by detecting the obscuration of the light source that occurs in the presence of smoke.In an aspirating smoke detection system, air samples are drawn, by a pump or fan, through sampling points (holes in the pipework) within the protected area, to a central detector.Combustion gas detectors, clause Combustion gas detectors are point-type detectors that respond to one (or more) of the gases produced by a fire. For example, carbon monoxide (CO) is produced when incomplete combustion occurs as a result of restriction of the amount of oxygen available to support the combustion process.Carbon monoxide can spread by diffusion through certain forms of construction. In the event of fire, therefore, carbon monoxide detectors could operate at a considerable distance from the fire, and on floors other than the floor of fire origin. Care needs to be taken to ensure that this does not result in misleading information for fire-fighters or others responding to a fire signal. Electrochemical sensors within combustion gas detectors have a finite life, after which replacement is necessary. It is important that the user is made aware of the likely lifetime of any combustion gas detector used within a fire detection and alarm system.
29 SITING DETECTORS Vertical structures: Enclosed stairways L1,L2,L3,L4,P1,P2Top of stairwayEach main landingFlue-like structuresLifts, Risers etcL1,L2,L3,P1TopWithin 1.5m of opening e.g.lift shaftSiting detectors, clause 22For Categories L1, L2, L3, L4, P1, P2, in enclosed stairways, detectors should be sited at the top of each stairway and on each main landing. Stairways are escape routes, so optical smoke detectors should preferably be used, [ref clause 8.2 c) and 21.8 d)]For L1, L2, L3, P1, in flue like structures (e.g. lift shaft, open riser, dumb waiter) a fire detector should be sited at the top of each flue like structure and within 1.5m of each ceiling penetration (outside the shaft).BS does not recommend the type of fire detectors to be used at the top of flue like structures, but the most suitable is likely to be optical smoke detection.
30 SITING DETECTORS - VOIDS Voids, smoke or heat to suit riskIf appropriate to Category,L1,L2,L3,P1all voids more than 800mm deepFloor or ceiling voidsConsider for smaller voids if risk assessment justifiesLantern lights (sky lights) more than 800mm deep800mm or moreLess than 800mmData and power cablesProtection of voids, clause 22.2 d)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 height need not be protected, unless either:1) the void is such that extensive spread of fire or smoke, particularly between rooms and compartments, can take place before detection; or2) on the basis of a fire risk assessment, the fire risk in the void is such as to warrant protection of the void.Lantern Lights (sky lights)If any lantern-light within a protected area (as determined by the Category) is 800 mm or more in depth, or is used for ventilation, a fire detector should be sited in the lantern-light.800mm or more
31 COVERAGE for point detectors Spacings specified in BS 5839 part 1 (2002)Any point in a room to a detector should be less than:7.5m for smoke detectors5.3m for heat detectorsEscape route up to 2m wideSmoke detectors up to 15m apart, 7.5m to endCorridor up to 2m wide – (Category P only)Heat detectors up to 10.6m apart, 5.3m to endDetector coverage, clause 22.3Detectors should be spaced at up to the stated limits for sufficient sensitivity to detect a fire quickly.BS 5839 part 1 requires that no point in a room should be further than 7.5m from a smoke detector and 5.3m from a heat detector.These figures are arbitrary and if in an installation there was a slight extension in a specific small area, then this would be the subject of a variation.For an aspirating detection system each sampling point may be regarded as a point detector, so the figures given for smoke detectors apply.For escape routes and corridors up to 2m wide there is no need to calculate the exact spacings, the figures given can be used.
32 SMOKE DETECTOR: spacing CORRIDOR 5m WIDE detectors on centre line5m7.5m14.1m15mUp to 2m wide corridorarea x 10.6 = 112sq mOPEN AREA10.6m5.3mSmoke detector spacing distance into a corner is 7.5m and in a regular square array a diagonal of 15m and a side to a square of 10.6m.Note that 10.6 x 10.6 = 112 sq m.The total area of the 7.5m radius circle would be 176 sq mIn corridors the spacing becomes greater than 10.6m and approaches 15m because of the way the radii intersect the width of the corridor.These spacings also apply to CO combustion gas detectors.When used in an escape route CO detectors should not be used as the sole means of detection, but mixed with optical smoke detectors.
33 HEAT DETECTOR: spacing 5mCORRIDOR 5m WIDE detectors on centre line5.3m9.4marea 7.5 x 7.5 = 56sq mOPEN AREA7.5m3.8m10.6mUp to 2m wide corridorHeat detector spacing distance into a corner is 5.3m and in a regular square array a diagonal of 10.6m and a side to a square of 7.5m.Note: heat detectors (fixed or rate of rise) are not suitable for escape routes.Note that 7.5 x 7.5 = 56 sq m.The total area of the 5.3m radius circle would be 88 sq m
34 Wall mounting 150mm to 300mm below ceiling DETECTION IN ROOMSWall mounting 150mm to 300mm below ceilingL3 escape route150300Wall mounting of detectors, clause 22.3 e)Wall mounting of detectors is permitted in BS (2002) and figures for positioning the detector on the wall below the ceiling level and above the top of the door are included. The detector should be close to any door opening onto the escape route.Wall mounted detectors should be sited such that: the top of the detection element is between 150 mm and 300 mm below the ceiling; and the bottom of the detection element is above the level of the door opening. NOTE Care should be taken in rooms with a high ceiling height (for example height exceeding four metres).i.e. No closer than 150mm from ceiling levelNo further than 300mm from ceiling levelAbove the level of the top of the door (i.e. not necessarily directly above the door).NOTE Where an automatic sprinkler installation initiates a fire alarm signal, via the fire alarm system, on flow of water from a single sprinkler head, a sprinkler head within a room may be regarded as an automatic fire detector, i.e. it is equivalent to the recommendation requiring detection in rooms opening onto escape routes for Category L3.Presenter’s note: This does not imply that all rooms opening onto an escape route can be protected with wall mounted detectors. If there is an increased risk of ignition in the room, such as a kitchen, or the room is quite large with a sleeping risk above, then the system would become Category L2 and ceiling mounted detectors should be fitted at the normal spacings. The decision on the Category should be part of the risk assessment process.Above door onlyGreen = o / kRed = not allowed.Wall mounted L3.Ceiling mounted L1 to L3.
35 DETECTORS: partitions and walls 500mm minimum if = wallceilingceilingless than300mm = wallmore than 300mm ignore500mm minimum clear space500mm minimum from wallPartitions and walls, clause 22.3Partitions can obstruct the flow of smoke/heat but if the gap between the top of a partition and the ceiling is more than 300mm the partition can be ignored.Partitions, clause 22.3 i)Closer than 300mm below ceiling - treat as a wall*More than 300mm below ceiling - no effect*When treating as a wall, detectors should be fitted both sides of the partition and no closer than 500mm.Walls, clause 22.3 g)Detectors should be at least 500mm from a wall.NOTE. If an enclosed area has no horizontal dimension greater than one metre, it is impossible to comply with this [500mm from a wall] recommendation; this should not be regarded as a variation, but the detector should be sited as close as possible to the centre of the space.Clear space around a detector, clause 22.3 n)There should be a clear space of a least 500mm below and around each detector.wallfloor
36 Differences between Non addressable and Analogue Addressable.
37 TECHNOLOGY : non-addressable RADIAL SOUNDER WIRING (FIRE RESISTANT)Z1Z2Z3Non-addressablepanel (P)RADIAL CIRCUIT WIRING IN FIRE RESISTANT CABLEAncillary (door retainer)Single fault limit 2000sq mConsider two systems each with the same detectors, but this one non-addressable, the analogue addressable follows.In this non-addressable system the radial zone circuits and radial alarm circuits are separately wired, in fire resistant cable.Notice that multiple fires in a zone circuit will only indicate once at the cie. Also after the alarms have been silenced, they will not resound if the fire in the original zone grows.Installation of detectors, call points and sounders is straightforward because no address settings are required.
38 TECHNOLOGY: Addressable or Analogue addressable I/FAll loop wiring in fire resistant cable654321Addressable or Analogue addressablepanel789101112131415161817Ancillary19Max. loop area 10,000sq.mThe zones shown are identical to the Non-addressable system.The loop should not exceed 10,000sq m so that the effect of two simultaneous faults is limited.Isolators limit the effect of a s/c fault. Isolators should be sited so that if a fault occurs between two isolators, the area affected is limited to 2000sq m.Most cie panels have isolators in the panel.Installation of each addressable device needs an address number to be set This may be using hardware switches or using auto/soft addressing. In either case address details are noted on a plan or table and location text is entered.Addressable interface units are available for use on addressable or analogue addressable systems for receiving from or sending to other equipment, such as:a) Sounders for phased evacuation or alert on an area by area basisb) A non-addressable zone of detectors and/or call pointsc) Another fire alarm paneld) An ancillary service, e.g. door retainer/releasee) An optical beam detectorAll loop cable should be fire resistant.
39 TECHNOLOGY : states Analogue addressable Non-addressable Detector outputNon-addressableAlarmPre-alarmNormalFire stateNormal stateFaultThe major advantage of an analogue addressable system is that the output of an analogue addressable detector is variable and is a proportional representation of the sensed effect of fire (i.e. smoke, heat, flame). In an analogue addressable system the analogue addressable detectors are transducers which send status information to the cie. Microprocessor based circuitry in the cie interprets the analogue value received and decides the condition of the cie, whether or not to indicate an alarm, pre-alarm, normal or fault condition.Normally the analogue signal is at a low level, but if there is a slow building fire the analogue level will slowly rise and reach the pre-alarm threshold. The responsible person or duty person can then investigate. If the fire continues to build the cie will sense the fire threshold and sound the alarms.In certain applications the sensitivity may be adjusted depending on the time of day or usage. For example in a night club the smoke detectors may be set less sensitive at night, but in an office they may be set more sensitive at night.Non-addressable detectors can signal only two output states, that is 'normal' and 'fire alarm'. Consequently, with these detectors it is impossible to know how close the device is to an alarm condition at the panel. However, devices on non-addressable systems can have additional device functionality e.g. individual identification of device, for maintenance and fault finding, and interrogation for levels of contamination.In both types of system, in a fire condition or state, the LED indicator on the detector shows to identify locally the origin of the fire.timePanel indicationPanel indicationDetector indicationDetector indication
40 TECHNOLOGY : comparisons Non-addressableAnalogue addressableday/night sensitivity NO YESDisablementby zonesby zonesonlyindividual detectors,zones or areasLocationsingle fireZONESZONESZONESZONE 1, ADDRESS 33ROOM 127, FLOOR 1ZONE 2, ADDRESS 60multiple fires different zonesTechnology The decision of whether to use smoke rather than heat detectors will be taken in the risk assessment and in the previous L, P categorisation stage. However, an important decision on whether to use Non-addressable or analogue addressable technology needs to be taken. The dividing line between the two technologies is not necessarily determined by the size (area) of the system, the number of detectors, or the number of zones. The user may want to know exact information regarding the location of a fire, the fire authorities may have a problem with search distances, the designer may want to phase the evacuation in a particular way, or a safety procedure may require a pre-alarm function, variable day/night sensitivity or multiple detector identification in a zone.Notice that in all cases the analogue addressable system provides exact location information comprising, address, zone, room, event and device type (e.g. MCP). This may be useful in the case of multiple fires in the same zone, where the Non-addressable only shows one indicator, but the analogue addressable shows all fires (using a scroll facility) with exact locations thus confirming the spread of fire or confirming that it is not a false alarm.ROOM 227, FLOOR 2scrollmultiple fires same zoneZONE 1, ADDRESS 33ROOM 127, FLOOR 1scroll
41 TECHNOLOGY : features Cost Faults, e.g. detector removed non-addressable is lower cost for smaller systemsFaults, e.g. detector removedAddressable or analogue addressable, the address is identifiedNon-addressable, identified to radial circuits (zone 0nly)Faulty detector or incorrect type of deviceA-A identifies address - not in non-addressableWiring faultNon-addressable, radial circuitAddressable identifies between devices if sequentialServicingContamination can be displayed on A-A panelCost of non-addressable is historically lower, but the cost of analogue systems is reducing. Non-addressable is likely to be economical for small systems and straightforward premises. Installation can be simpler.Analogue addressable is more expensive to install, the component parts being more expensive. Savings can often be made on cable and life costs in maintenance.Other advantages may be more important than installed cost. For example device fault and fire indication on non-addressable systems is by radial circuit only, but for addressable it is by individual devices.For Analogue addressable systems the identification of the device (e.g. heat or smoke detector) can be used to display a fault if the wrong type has been plugged in.The exact location of non-addressable wiring faults would have to be found on radial circuits by individual tests.Analogue addressable wiring faults on long loop circuits may be difficult to locate. It is advisable to connect the device addresses in sequence to aid fault identification.To service a non-addressable detector and check whether contaminants are affecting the sensitivity the detector will need to be cleaned or re-furbished. However, devices on non-addressable systems can have additional device functionality e.g. individual identification of device, for maintenance and fault finding, and interrogation for levels of contamination.Presenter’s note: final sentence repeated from slide 24.For analogue addressable detectors, the back ground level of contamination can be displayed and compensated for at the panel, simplifying maintenance decisions.
43 Some legislation updates… BS5839 PT 1 :1988WILL BE WITHDRAWN ON 15 JULY 2003ALLSERVICING, DESIGNS AND INSTALLATIONS WILL BE TO THE NEW BS 5839PT 1:2002 FROM 15/7/2003.
44 SYSTEM COMPONENTS Voice alarm systems BS 5839-8 Alarms BS EN 54-3 Heat det BS EN 54-5Smoke det BS EN 54-7Linear heat det draft BSInterfaceOptical beam det BS pr EN 54-12MCP BS EN 54-11CIE BS EN 54-2POWER SUPPLY BS EN 54-4System components, clause 11BS EN Standards:Control and indicating equipment BS EN 54-2.Audible fire alarm devices BS EN 54-3.Power supply equipment BS EN 54-4.Point heat detectors BS EN 54-5 for Class A1 or A2 detectors, unless the foreseeable maximum ambient temperature in the protected area is 40 ºC or above, in which case a Class B-G detector should be used as appropriate, taking into account the avoidance of false alarms.Point smoke detectors BS EN 54-7.Flame detectors BS ENManual call points BS EN for Type AThe closest EN to BS is the draft (pr)EN 54-14, but this is mainly informative and is likely to be published as a guide rather than a Code of Practice or Standard.BS:BS Code of practice for the design, installation and servicing of voice alarm systems.BS (1988) Specification for optical beam smoke detectors. This is likely to be replaced by the draft pr ENbs for linear heat detector devices is in draft form.TEST AFlame det BS EN 54-10
46 FALSE ALARM MANAGEMENT Consultation with all partiesAppoint a responsible person - RPSupervise painting, decorating, hot workRecord and compensate for any change of useKeep fire alarm logbook up to dateAgree an acceptable rate of false alarms (e.g. less than 1 false alarm per 100 detectors per annum)Ensure service and maintenance carried outIf no effort to limit – system is not compliantFalse alarm management, Section three, clauses 30, 31, 32Most importantly, to help avoid false or unwanted alarms, a responsible Most importantly, to help avoid false or unwanted alarms, a Responsible Person (RP) should be appointed at the premises to take action and avoid a recurrence of any unwanted event by procedures and equipment control. Procedures would include supervising painting and decorating or hot work. The responsible person would also be able to record and control any change of use of the building.The RP should ensure that the log book is kept up-to-date, with a record of all fire drills, routine tests, servicing and false alarms.Agreement on an acceptable rate of false alarms is essential so that a target is set. The example of less than 1 false alarm per 100 detectors per annum could be achieved in a clean office environment with good maintenance and careful working procedures. In less favourable conditions, the target may be lower.Ongoing false alarm management would include keeping the fire alarm system logbook up to date and ensuring that service and maintenance is properly carried out and recorded. If there is no attempt by the RP to limit false alarms, the fire alarm system should no longer be considered as compliant with BS
47 CATEGORIES OF FALSE ALARM False alarm categories:Equipment false alarmsFaults in equipmentUnwanted alarms (equipment works perfectly)Fire-like phenomena, e.g. smoking, burning toast, hot work, building workMalicious false alarmsFalse alarms with good intentCategories of false alarm, clause 31Equipment false alarms should be avoidable with good design, installation and maintenance.Unwanted alarms are dependent on building management procedures. The equipment is working perfectly, but something is creating a fire-like phenomenon. The handover and maintenance engineers should be able to instruct the user on avoiding unwanted false alarms.Malicious false alarms might be reduced by carefully placing manual call points, or by agreeing certain procedures with the fire authorities.False alarms with good intent. Someone has made a mistake. Training for personnel might reduce this type of false alarm.
48 CAUSES OF FALSE ALARMS fumes steam tobacco smoke; dust insects aerosol sprayhigh air velocitieshot workbonfiresincensecandleselectromagnetic interferencehigh humiditywater ingresstemperature changesaccidental damageCauses of false alarms, clause 33Fumes from cooking processes (including toasting of bread); Steam (from bathrooms, shower rooms and industrial processes); Tobacco smoke; Dust (whether built up over a period of time or released from an industrial process); insects; aerosol spray (e.g. deodorants and cleaning fluids); high air velocities; smoke from sources other than a fire in the building (e.g. from an external bonfire); cutting, welding and similar “hot work”; processes that produce smoke or flame (e.g. flambéing of food); cosmetic smoke (e.g. in discotheques and theatres); incense; candles; electromagnetic interference; high humidity; water ingress; substantial fluctuation in temperature; accidental damage (particularly to manual call points); testing or maintenance of the system, without appropriate disablement of the system or warning to building occupants and/or an alarm receiving centre. pressure surges on town mains serving automatic sprinkler systems that are interfaced with the fire alarm system.Most of these causes can be minimized by appropriate choice of detection system and suitable management arrangements
49 FALSE ALARMS (SEC35.2.6)Systems with 50 or more devices require a 1 week soak test (defined by the Designer and built into the Tender).If it False Alarm’s then identify the Alarm, rectify it and start the 1 week soak test againUntil successful the system should not be regarded as an operational means of giving warning of a fire in the building. During this soak all MAC’S should bear an indication that it is not to be used. When all clear carry out the final hand over.
51 MAINTENANCE and the LAW Fire Precautions (Workplace) Regulations require a system of maintenanceSystems with no battery backup are not legalCompetent Person should advise users to replace urgentlyFailure to keep the fire detection and alarms in good working order is a criminal offenceArranging a suitable system of maintenance is so easy to do, that neglecting to do it is blatant flouting of the law.If a fire alarm system is deemed to be necessary then a system of maintenance is required. Otherwise the user may be liable for prosecution.Quote from the Fire Precautions (Workplace) Regulations :“6. Maintenance. Where necessary in order to safeguard the safety of employees in case of fire, the workplace and any equipment and devices provided in respect of the workplace under regulations 4* and 5 shall be subject to a suitable system of maintenance and be maintained in an efficient state, in efficient working order and in good repair”. end of quote * Regulation 4 refers to Fire detection and alarms..The “shall” means that it is obligatory, failure to comply being an offence. The HEALTH & SAFETY (SAFETY SIGNS & SIGNALS) REGULATIONS (1996) requires that fire alarm warning systems must be provided with a guaranteed emergency supply in the event of a power cut, unless the hazard has thereby been eliminated. This means that systems not having a standby power supply (battery back-up) are no longer legal.This is also a law, failure to comply being an offence.Reference BS , clause 46.2 b) 4. BSThe Competent Person (CP) should follow the recommendations in the Code of Practice BS All fire equipment should be kept clear of obstructions. Regular maintenance and replacement of faulty and worn out parts should reduce the likelihood of false alarms.
52 The HEALTH & SAFETY (SAFETY SIGNS & SIGNALS) REGULATIONS (1996) Require that fire alarm warning systems must be provided with a guaranteed emergency supply in the event of a power cut, unless the hazard has been eliminated.This means that systems not having a standby power supply (battery back up) are no longer legal.This is also a law, failure to comply being an offence.
53 MAINTENANCE - Non Routine Attention Special inspection on appointment of new service companyAttendance available 24/7 within 8hTests following modificationsAction to address unacceptable false alarmsTests following long periods of disconnectionMaintenance, section Six clause 46. Non Routine Testing New Service Contract. When a service company takes over a service arrangements for an existing site, special inspection should be carried out to investigate and report on major areas of non compliance of: MCPs; detection; sound pressure levels; standby power supplies; cabling; monitoring; electrical safety; false alarms; layout and construction.Attendance to be available 24/7 and on site within 8 hours (otherwise subject to variation) ref clause The service organisation contact details should be prominently displayed. Modifications Any modification work complies with BS and certificate issued. Tests of all areas affected by field modifications Tests of one detector in every circuit if cie has been modified.False alarms Where there is an unacceptable rate of false alarms the CP may be requested to investigate and modify accordingly. After any modification, the system should as compliant as before the modifications. Documentation to be issued.Tests and inspection following long periods of disconnection, clause Maintenance as per the recommendations over a 12 month period should carried out.
55 BS5839 PT 1 :2002 (sec18.1&2)If people are moving freely around the building then visual indication preferably RED should be installed in all necessary places, and associated toilets.Caution consider photosensitive epileptics when using strobes.If they are sleeping in the building then tactile devices may be required. For example placed under a pillow wired into the fire alarm circuit.Other options may be vibrating pagers.
57 DOCUMENTATION AND CERTIFICATION Installation CertificateCommissioning certificateAcceptance CertificateVerification certificate (optional)Maintenance CertificateDocumentation, clause 40Relevant information discussed earlier for all aspects from consultation through design to installation and commissioning should be available to hand to the responsible person or user on site.Certification, clause 41BS (2002) now recommends that Certificates should be issued for all aspects of the fire alarm system:Design, clauses 5.2 h) and 41.2Installation Certificate, clause 36.2 n)Commissioning certificate, clause 39.2 f)Acceptance Certificate, clause 42Verification certificate (optional), clause 43Maintenance Certificate, clause 45.4 (end of clause)BAFE SP203 This is a modular scheme covering all aspects from design, installation, commissioning, verification to maintenance, each being a separate module. Companies would be certified to one or more of the modules.LPS 1014 This scheme covers all aspects (design, installation, commissioning, verification, maintenance) in one certificate. Companies are approved to all aspect of the scheme.Service and Maintenance Schedule, clauses 44 to 46 For continuing safety it is important that the fire alarm system is tested and maintained on a regular schedule, and it is recommended that a contract for this is agreed at commissioning. Records and evidence of this should be kept with the logbook.FINAL TEST