Source: http://elc-ltd.com/firealarm.php
Timestamp: 2019-05-20 18:33:11
Document Index: 541326087

Matched Legal Cases: ['art 2', 'art 1', 'art 6', 'art 6', 'art 1', 'art 1', 'art 6', 'art 6', 'art 6']

Type L2 Fire syste m only installed in a defined part of the building.
A fire compartment is an area bordered by a fire resisting structure with a resistance of at least 30 minutes. If a stairwell or a similar structure extended beyond one floor but was in one fire compartment, the stairwell should be a separate zone. If the zone covered more than one fire compartment, the zone boundaries sh ould follow the compartment boundaries.
The type of control panel will depend upon the size of the building and the extent of the automatic protection provided. The panel is chosen according to the number of zone and sounder circuits, ancillary control relays, battery standby time and any other individual customer requirements. The central control panel must be positioned in a low fire risk area that provides the Fire Brigade with easy access in cases of emergency. The area must be well lit, therefore provision of emergency lighting may be necessary. A plan of the building and the zone locations must be kept beside the control panel.
Smoke and heat detectors are placed at the highest points of the enclosed areas, as this is where smoke and heat from fires is most concentrated. The heat sensitive element of a heat detector should be sited between 25mm and 150mm below the ceiling or roof. The smoke detector's sensor element should be sited between 25mm and 600mm below the ceiling or roof. If the area has a pitched o r north light roof, smoke detectors should be installed in each apex.
If a call point is to be used on a 240V AC supply the provision of earth continuity between external circuits is required in order to20comply with paragraph 4.1.7 of BS 5839, Part 2.
No matter how small the system, a minimum of two sounders are required and the correct sound levels must be maintained in all parts of the building. The sound level is reduced by approximately 20dBA by a door and by approximately 30dBA by a fire door.
Multiple small sounders produce a better sound distribution than a few large ones. In some areas, a large number of quieter sounders may be preferable to a f ew very loud sounders to prevent noise levels becoming too loud. Due to individual site characteristics, sound level checks should be carried out to ensure minimum sound levels are obtained.
Connections to the mains should be via an isolating protective device e.g. an isolating switch fuse, the cover of the device should be red and should be labelled "Fire Alarm: Do Not Switch Off", Cables other than M.I.C.C. should be provided with mechanical protection when necessary i.e. if physical damage or rodent attack is likely, or if they are less than 2.25 metres above the floor. Mechanical protection may be provided by conduit, trunking or by laying in cable tray.
A commissioning certificate, log book and system diagram are required to be given to the system user upon the completion of an installation. After installation, every system should be regularly tested and serviced. BS5839 , Part 1 recommends the following:
The purpose of this simple guide is to assist specifiers and installers in complying with the recommendations of BS 5839 Part 6 when installing smoke alarms in dwellings and while every reasonable endeavor has been made to ensure the accuracy of the information, it is the responsibility of the reader to ensure that they satisfy the recommendations of the British Standard in any particular case. No liability is accepted for the consequences of any errors or omissions in this guide. The guide is not intended to be a substitute for the British Standard, the c ontents of which should be carefully studied by contractors installing smoke alarms in dwellings. There are a lot of similarities between the latter part 6 of BS 5839 1995 and the earlier BS 5839 Part 1 for commercial properties but in essence part 1 demands a fully monitored centrally controlled system with alert devices throughout the premises achieving at least 65 Db(A) with the following levels most commonly implicated but there are others.
For new dwellings, battery operated smoke alarms should not be used. These should only be used for retrofitting in existing bungalows, flats and owner occupied two storey houses in which there is adequate means of escape in the event of fire. Mains operated smoke alarms should be used for all new dwellings and for retrofitting in rented maisonettes and two storey houses. (They should also be used for single storey bungalows and flats if, for example, occupants could be trapped in a lounge, dining room or bedroom, due to a fire in another room through which it is necessary to pass in order to escape from the property; this might occur if, for example, there is a bedroom off a lounge, and there is no window in the bedroom suitable for escape.) Mains operated smoke alarms sh ould also be used in preference to battery operated devices if the occupants are considered to be at high risk from fire or if they may not be able to replace batteries soon after a low battery fault warning is given.
Warning: Installation of mains powered smoke alarms should be undertaken only by a qualified electrician. Installation should be undertaken in accordance with BS 5839 : Part 6 and BS 7671 (IEE Wiring Regulations). Mains-only smoke alarms with no battery back-up should be connected on a single independent, dedicated circuit at20the dwelling’s distribution board. No other electrical equipment should be connected to this circuit. The circuit should preferably not be protected by any r.c.d., whether dedicated to the circuit or common to all circuits derived from the distribution board. If, however, r.c.d. protection is essential for electrical safety, the British Standard recommends two options:
or (ii) The r.c.d. protection should be arranged so that the r.c.d. serving the smoke alarm circuit operates independently of any r.c.d. protection for circuits supplying socket outlets or portable equipment. (For example, this could be satisfied by a distribution board with a time delayed 100mA r.c.d. serving the entire board, and 30mA r.c.d. protection on socket outlets, etc. It would be expected that, in the event of earth leakage on a socket outlet circuit, the 30mA r.c.d. would operate without the 100mA r.c.d. necessarily operating.)
BS 5839 : Part 6 recommends that there be a method of silencing or disabling smoke alarms in the event of a prolonged false alarm, perhaps due to a fault or a build p of pollution in the detector chamber. However, to comply with BS 5839 Part 6, there20must be a means of silencing or disablement. This recommendation can be satisfied if the dedicated circuit serving the smoke alarms is protected by a miniature circuit breaker (as opposed to a fuse); the British Standard recognizes a miniature circuit breaker as a suitable and readily accessible means of silencing.
or (ii) a separately electrically protected, regularly used local lighting circuit. However, if the smoke alarms are connected to a lighting circuit, isolation of the detector for maintenance may be less convenient due to the need to isolate the lighting circuit.
Where cables pass through walls, a smooth clearance hole should be provided. If additional mechanical protection is necessary, a smooth-bore sleeve should be sealed into the wall. Care should be taken to ensure20that the ends of the sleeve are free from sharp edges. Cable penetrations should be filled and should maintain the fire resistance of any fire resisting walls or floors. Joints in cables should be avoided but, where unavoidable, should be enclosed in a suitable and accessible junction box. Reliable termination methods should be adopted.
Smoke alarms should be sited in accordance with the following guidance to ensure both adequate detection and alarm sounder audibility: ¯ At least one smoke alarm should be located between the sleeping areas and the most likely sources of fire (living room and kitchen).
¯ In a two storey house, at least one smoke alarm should be located on each storey. In a conventional two storey house, one smoke alarm should be sited on the ground floor between the staircase and any room in which fire might start. A further smoke alarm should be sited on the upstairs landing. ¯ Additional smoke alarms should be provided in long hallways of all dwellings. Within such circulation areas, no door to any room should be further than 7.5 m from the nearest smoke detector. In open-plan accommodation, where a stair may be open to a living/dining area, the living/dining area should be treated as a circulation area.
Occasional false alarms from smoke alarms are inevitable, but installers should site smoke alarms in such a way as to avoid unnecessary false alarms. However, avoidance of false alarms should never take precedence over effective fire detection. Guidance on selection of the most suitable type of smoke alarm in order to provide optimum fire detection while avoiding unnecessary false alarms. Note that the smoke alarm nearest to any kitchen should be of the optical type. This will normally be the case, because all smoke alarms in circulation spaces should normally be of the optical type. However, optical smoke alarms should not be sited close to bathrooms, showers or rooms from which steam may escape. Nevertheless, because these rooms normally open off circulation spaces, false alarms should normally be avoided by careful siting of the smoke alarms, rather than using ionisation chamber detectors. Alarm Sound Levels