CC1608 Fire Systems Design Guide Update1 Layout 1

1 FireA Guide to fire alarm Systems designBS 5839 Part 1:2002 The fire Installers MateCC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 12A Guide to bs 5839 Part 1:2002 DisclaimerThis booklet is not intended to be acomprehensive Guide to all aspects of fire alarm Design but rather a very usefulsource of background information. Whilst every care has been taken to ensurethat the contents of this document arecorrect at the time of publication, it shouldnever be used as any form of substitutionfor the bs 5839 standard itself. CooperSafety shall be under no liabilitywhatsoever in respect to such should be noted that there may bespecific additional requirements dependentupon local authority building regulationsand/or fire use this Guide in conjunction witha current issue of the bs 5839 Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 23P1P2L1L2L3L4 Property Protection fire SystemsPAFD designed to primarily protect property categories:P1 AFD installed throughout all areasP2 AFD installed only in defined areasLife Protection fire SystemsLAFD designed to primarily protect human life categories.

2 L1M plus AFD installed throughout all areasL2 AFD installed in defined areas of higher risk of ignition, in addition to L3L3M plus AFD installed in escape routes and rooms opening into these routesL4M plus AFD installed in escape routes comprising circulation areas and space such as corridors and stairwaysL5A non-prescriptive system in which protected area(s) and/or the location of detectors is designed to satisfy a specific fire risk objective (other than that of L1 to L4)MSystem designed to be operated manually (no AFD)AFD - Automatic fire DetectionCategorisation of fire alarm and detection systemsBS 5839 Clause 5 CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 3465dB(A)@500Hz to 1000Hz+5dB(A)@500Hz to 1000 HzBackground noiseThe minimum sound level of a sounder device should be 65dB(A)or 5dB(A)above a background noise (if lasting more than 30 seconds) and at a frequencybetween 500 Hzand maximum sound level should not exceed120dB(A).

3 Sounder device cabling should be arranged so that in the event of a fault atleast one sounder located within the vicinity of the control and indicating panelwill remain in 5839 Clause 5839 Clause Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 460m MAX45m MAXThe maximum zone floor area should not exceed 2000m2. A person searchinga zone for a fire should not have to travel more than 60m from the zoneentrance to identify the source of the person should not have to travel more than 45malong an escape route toreach a manual callpoint, when the Layout of the building is 5839 Section 5839 Clause 5CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page (+/-200mm) centre of the element of the manual callpoint should be positioned (+/-200mm)from floor level (unless a wheelchair user is likely to be the firstperson to raise the alarm, when this is applicable it should be noted on anycertification).

4 Visual alarms such as beacons should always be mounted at a minimum heightof floor level, in a position that is likely to attract 5839 Clause 5839 Clause 17CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 62m75dB(A)Unless MICC or armoured cable to BS7846 standard is used, considerationshould be given to the protection against physical damage from floor level tothe height of 2m. Except in relatively benign areas, such as shops, offices andsimilar, where cabling can be clipped to robust areas where people are sleeping, sounder devices should produce aminimum 75dB(A) at the bed-head with all doors shut. In buildings likely toprovide sleeping accommodation for the hearing impaired, considerationshould be given to the incorporation of both audio and visual 5839 Clause bs 5839 Clause Systems Design Guide_Update1_Layout 1 11/03/2010 09:56 Page 7 Smoke x = x = mounted on a flat ceiling, smoke detection devices have an individualcoverage of However these radii must overlap to ensure there areno blind spots.

5 Therefore individual coverage can be represented by a squaremeasuring x an actual coverage area of 112m2per mounted on a flat ceiling, smoke detection devices have an individualcoverage of However these radii must overlap to ensure there areno blind spots . Therefore individual coverage can be represented by a squaremeasuring x an actual coverage area of 5839 Clause bs 5839 Clause 8CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 8In corridors less than 2mwide the horizontal spacing of detectors can beincreased, the area of coverage need not overlap as in the case of a room. Any corridor over 2mwide is deemed as a room and most adhere as specified (see page 8).

6 Please note:Heat detectors are not recommended for use in corridors thatmay be used as escape detectors15m MAX2mBS 5839 Clause For ease of Design and assessment of coverage dimensions used fordetectors are usually taken as:Smoke:5m to wall / 10m between detectorsCoverage 100m2 to wall / 7m between detectorsCoverage 50m2CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 910X<1m>1mAir vent / Air conDecibel loss occurs through doors: Approximately -20dB(A) through a normaldoor, and approximately -30dB(A)through a fire door. Unless a sounder isinstalled in a bedroom, it is unlikely that 75dB(A) will be achieved. Do not site detectors less than 1mfrom air inlets or air circulating 5839 Clause fire doorBS 5839 Clause CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 10 Apex < 150mmHeat detectorApex < 600mmSmoke detectorTreat as a flat ceilingApex > 600mmSmoke detectorApex > 150mmHeat detectorCeiling with a apexFor ceilings that feature an apex: As long as the height of the apex fromthe rest of the ceiling is less than 150mm for heat detectors or lessthan 600mmfor smoke detectors, then these can be treated the sameas flat ceilings.

7 For higher apexes, a device should be installed at thehighest point. The distance to adjacent devices can be increased by1%per degree of angle of the roof up to a maximum of 25%. bs 5839 Clause 11 Detector TypeCeiling Heights (m)General LimitsRapid Attendance*(category P Systems only)Heat Detectors Smoke & CO fire SmokeNormal SystemsEnhanced (category 1)Very high high Beam Smoke Detectors A1 Other Classes* Rapid attendance within 5 minutesCC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 1112Z x 2 XZLight fitting/obstructuionA device should not be mounted within 500mmof any obstruction. If the top ofa solid partition is less than 300mmfrom the ceiling then it should be treatedas a wall.

8 Similary, ceiling obstructions such as beams should be treated aswalls if deeper than 10%of the ceiling height (particularly important in voids).For obstructions less than 250mmdeep never mount devices closer than twicethe depth of light fittings or other obstructions in the ceiling. bs 5839 Clause BeamPartition>10%ceilingheight<500mmX<500mmX<300mmBS 5839 Clause CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 12>800mmLift ShaftLift less than 800mmin height are required to have a risk assessment todetermine if AFD is required. Voids in excess of 800mmdo require shafts like lift shafts and stairways should have a device mountedwithin of any 5839 Clause bs 5839 Clause 13CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09.

9 57 Page 1314X102030405060708090100 Time of day<29 C<4 CMaximum temperatureAverage ambient temperatureXXTemperatureEnclosed stairways should have a detector on the topof the stairway and oneach main minimum static response to heat devices should not be less than29oCabove the average ambient temperature, or less than 4oCabove the highesttemperature the device can be expected to 5839 Clause bs 5839 Clause CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 14 Smoke detectorsOptical/Ionisation ChamberX25mm600mmXHeat detectorThermistorX25mm150mmXThe sensing element of a smoke detection device (optical smoke chamber)should not be less than 25mmbelow the ceiling, and not greater than 600mmbelow the sensing element of a heat detection device should not be less than 25mmbelow the ceiling, and not greater than 150mm below the 5839 Clause bs 5839 Clause Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 1516 SecondGroundFirstZone 1 Zone 2 Zone 3 Zone 4 Zone 1 Zone 2 Zone 3 Zone 4 Zone 2 Zone 3 XLess than 300m2can be covered by a single zone.

10 When the total floor areaexceeds300m2, each floor would require a zone (or zones if the floor areaexceeds 2000m2) with access, stairwells or lifts covered by a zone should not cross 5839 Clause bs 5839 Clause CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:57 Page 1617 Mains supplyEOL fittedEOL fittedTo comply with the current version of the bs 5839 Part 1, the use of fireresistant cables are required for all critical circuits, this includes detection,sounders and mains a loop system , short circuit isolators are required to limit the effect of onefault to less than 2000m2 floor area. 2 simultaneous faults on a circuit shouldnot disable protection within an area greater than 10, 5839 Clause 26 bs 5839 Clause CC1608_Fire Systems Design Guide_Update1_Layout 1 11/03/2010 09:58 Page 1718 For local isolation during maintenance, a suitable double pole isolator should be provided, suitablymarked ( & f).