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N o t e b o o k Fire Alarm r ea t ed 28-Se -12 10:03 AM Upda ted 23-Se -13 8:46 AM

Fire Alarm according to BS5839 Part1:2002

Zone R equirements:

1. The total area of a zone must not exceed 2000m22. Only one zone is required if the total area is not greater than 300m23. Zone boundaries shall f ollow compartments boundaries4. No zone shall be split between two occupancies5. A person searching a zone f or a f ire should not have to travel more

than 60m to identif y the source of a f ire.

Fir e Alar m System ClassificationsBS5839 Splits f ire alarm systems into 3 categories. These 3 categories areCategory P Systems, Category L Systems and Category M Systems.

All the systems described below are expected to have manual call points onall f inal exits, entrances to stairwells and corridors where persons are notexpected to walk more than 45 metres to operate a call point.

1. Categor y P: Category P Fire Alarm Systems designed specif ically f or protection of

property only. Category P systems are split into 2 classif ications P1 or P2.The dif f erence between a P1 and a P2 system is that a P1 system isdesigned to protect the whole building, whereas a P2 system is installed indef ined parts of the building only. These def ined parts of the building maybe areas with an extraordinary high f ire risk or hazard.

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2. Category L: Category L Fire Alarm Systems These systems are split into 5classif ications L1, L2, L3, L4 and L 5.

L1: BS5839 L1 classif ication includes automatic f ire detection in allrooms , on all escape routes and in all voids over 600mm inheight . Sounders positioned throughout the building to achieve a minimumof 65dB(A) throughout the building and 75dB(A) at bedhead where there isa sleeping risk. In areas of high ambient noise sound levels the f ire alarmsound levels should be 5dB(A) above the normal noise level although notexceeding 120dB(A).

L2: BS5839 Classif ication L2 System should include automatic f ire

detection on all escape routes and r ooms leading onto escaperoutes . An L2 system can also include additional areas deemed as ahigh r isk not included in the escape routes and adjoining rooms, such asboiler houses. The sounders in the building should be according to thedescription in the BS5839 Category L1 description as above.

L3: BS5839 Classif ication L3 system is very similar to a category L2system in that automatic f ire detection should be positioned on escaperoutes and adjoining rooms , although it does not have to include f or

additional areas deemed to have a high f ire risk. The sounders in thebuilding should be according to the description in the BS5839 Category L1description as above.

L4: BS5839 Classif ication L4 system includes automatic f ire detection onescape r outes only , and not in the adjoining rooms as per the L2 and L3classif ications. The sounders in the building should be according to thedescription in the BS5839 Category L1 description as above.

L5: BS5839 Classif ication L5 System is designed for buildings thathave a par ticular fir e r isk identif ied which warrants some specialattention. For example if there is an area of high f ire risk which isconsidered worthy of having some automatic detection but a manual systemis also needed, then this will be termed as L5/M. The sounders in thebuilding should be according to the description in the BS5839 Category L1description as above.

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8. When mains voltage sounder are used in addition to 24V DC sounders,the mains sounder sypply must be monitored.

Smoke Detectors:

1. Smoke detectors have an individual coverage of 7.5m radius. however,these radii must overlap to ensure there are no "blind spots". theindividual coverage can theref ore be represented by a squaremeasuring 10.6mx10.6m giving an actual area coverage of 112m2 perdevice. Overlapped radius 5.3m

2. In corridors less than 2m wide, the radius can be increased to 7.5m.There is no need f or overalp. Any corridor over 2m wide is deemed aroom and device spacing should f ollow the standards f or rooms.

Heat/Rate of Rise Detectors:

1. Fixed temperature heat detectors suitable in environments wherethere is a high ambient temperature or in areas where sudden chagesin the ambient temeratures are common e.g. biler rooms, dryingrooms, kitchens.

2. Rate of rise detectors are designed to detect a f ire as the temperatureincreases. These detectors are suitable where the ambient tempratureis stable and a f ast to sudden temperature increase is reuired, e.g.

areas unsuitable f or smoke detection due to dust.3. Heat detection have an individual covetage of 5.3m radius. However,

these radii must overlap to ensure there are no "blind Spots"/ Theindividual coverage can theref ore be represented by a squaremeasuring 7.5mx7.5m giving an actual area coverage of 56.25m2 perdevice. Overlapped radius 3.5m.

4. In corridors less than 2m wide, the radius can be increased to 5.3m.There is no need f or overalp. Any corridor over 2m wide is deemed aroom and device spacing should f ollow the standards f or rooms.

Maximum Ceiling Heights for detectors:

1. Smoke detector 10.5m2. Fixed heat detector (58C) 9m3. Fixed heat detector (78C) 6m4. Optical beam smoke detector 25m

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General Notes: 1.Do not site detectors less than 1m f rom air inlets or air conditioningunits.

2. Detectors should be mounted within 500 mm of any obstruction.3. If the top of a solid partition is less than 300mm f orm the ceiling, it

should be treated as a wall.4. Ceiling obstructions such as beams should be treated as walls if they

are deeper than 10% of the ceiling height. 5. Minimum distance between detector (other than beam detectors) andwall or partition should be 500mm 6. Corridors greater than 5 metres wide treat as f or f lat horizontalceilings.f or a corridor with a width of say 1.5m, the maximum distance f rom adetector can be increased:f or a smoke detector by: (5m - 1.5m)/2 = 1.75m + 7.5m = 9.25f or a heat detector by:- (5m - 1.5m)/2 = 1.75m + 5.3m = 7.05

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5. Fire resistant cable is required within the whole f ire alarm system

including the mains supply cables. (the use of non-f ire resisting cables willno longer comply with BS5839) 6. Never mount detectors closer than twice the depth of a luminaire. 7. Voids more than 800mm need to have independent coverage, unlessf ire or smoke is able to spread f rom one area to another through the void.

8. Vertical shaf ts like lif ts and stairways should have a detector mountedwithin 1.5m of any opening.

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9. Enclosed stairways should have a detector on each main landing. 10. The sensing element of a heat detector should not be less than25mm below the ceiling and not greater than 150mm below the ceiling. 11. The sensing element of a smok e detector should not be less than 25

mm below the ceiling and not greater than 600 mm below the ceiling. 12. Any non mechanically protected cable medium should have additionalprotection up to 2m f rom f loor level. 13. If the height of a ceiling apex is less than 150 mm f rom the rest ofthe ceiling f or heat detectors and 600mm f orm the rest of the ceiling f orsmoke detectors, it can be treated as f lat ceilings. For higher apexes, adevice should be installed at the highest point. The distance to adjacentdevices can be increased by 1% per 1 degre of the angle of the roof up to amaximum of 25%.