BUILDING REGULATIONS Fire detection and fire …

1 6 NAPIT0870 444 1392 this article we shall look at the requirements of BS5839: fire detection and fire Alarm Systems forBuildings. Due to the volume of information in thisstandard we will limit the content to an overviewinvolving the following parts Part 1: Code of PracticeFor System Design, Installation, Commissioning andMaintenance; Part 6: Code of Practice for the Design,Installation and Maintenance of fire Alarm Systems 1In general, it is appropriate to install some form of firealarm system in all buildings other than very smallpremises that are open plan in cases where there is uncertainty regarding theneed for a fire alarm system, or the category of asystem, reference should be made by the developer,potential purchaser or user to the following: guidance documents that support fire safetylegislation any authority responsible for enforcing fire safety legislation the insurer of the property any relevant fire risk of systemFire alarm systems are usually installed in buildings tosatisfy one or more of the following objectives.

2 Protection of life protection of property protection against business interruption protection of the M systems are manual systems, forexample a manually operated bell. Category Lsystems are automatic fire detection systemsintended for the protection of systemsare installed throughout all areas of abuilding, to offer the earliest possible warning of a fireto allow the longest possible time for escape. L2 systemsare installed in defined parts of abuilding. The system should meet the requirements ofa category L3 system, with the additional objective ofproviding early warning of fire in specified systemsare designed to give a warning of fireat the early stage to enable all occupants, other thanthose in the room where the fire originated to escapesafely, before the escape routes become impassabledue to the presence of fire , smoke or toxic systemsare installed within escape routesconsisting of circulation areas and spaces, egcorridors and stairways, to enhance the safety of theoccupants by providing early warning of systemsprotect areas.

3 The location ofdetectors is designed to satisfy a specific fire safetyobjective not covered by any of the previous Psystems are automatic fire detectionsystems intended for the protection of property sub-divided into two systemsare installed throughout all areas ofthe BUILDING , to offer the earliest possible warning of afire in order to minimise the time between the ignitionof the fire and the arrival of the fire systemsare installed only in defined parts of abuilding, in order to provide early warning of a fire inhigh fire hazard areas or areas in which the risk toproperty or business continuity from fire is 6 This code of practice covers fire detection and alarmsystems specific to risk assessment for dwellingsThe final design of a fire detection and fire alarmsystem for a particular dwelling should wherereasonably practical be based on a fire assessing the fire risk each room needs tobe considered separately.

4 Account needs to be takenof the statistical data when assessing the probabilityof fire . Table in part 6 of BS5839 titled RelativeFrequency Of fire in Rooms Within Dwellingsprovides such information. The table is based oninformation provided by The Office of The DeputyPrime Minister, which has been replaced by TheDepartment for Communities and Local simplified version of this table is shown , bedsitting room12 Living room, dining room12 Access area6 Refuse area3 Store room2 Bathroom, cloakroom, WC2 Roof space1 Laundry1 Airing cupboard, drying cupboard1 Miscellaneous and unknown7 Other factors which need to be considered are: the detection and warning objectives characteristics of the occupants lifestyle factors sources of ignition considerations for protection of detection and fire alarm systemsFire detection and fire alarm systemsDon Holmeslooks in detailat the lawregardingthis importantarea of firepreventionBUILDING REGULATIONSG rades of system for dwellingsThe standard provides detail of six grades of A systemis a fire detection and fire alarmsystem which incorporates control, indicatingequipment and power supply equipment conformingto standards BS EN54-2 and BS EN54-4 B systemis a fire detection and fire alarmsystem comprising fire detectors (other than smokeand heat alarms).

5 fire sounders, control andindicating equipment and power supplies conformingto BS EN54-2 and BS C systemis a system of fire detectors andalarm sounders connected to a common powersupply, consisting normal mains and a standbysupply with central control D systemis a system of one or moremains powered smoke alarms, where each alarm hasan integral standby E systemis a system of one or moremains powered smoke alarms with no F systemis a system of one or morebattery powered smoke of systems for dwellingsForthe purpose of Part 6 of BS5839 systems areclassified as LDis a fire detection and alarm systemintended for the protection of life and is sub dividedinto three 1is a system installed throughout a dwelling,incorporating detectors in all circulation spacesforming part of an escape route, also in all rooms andareas, in which a fire may start (excluding toilets,bathroom and shower rooms).

6 LD 2is a system incorporating detectors in allcirculation spaces that form the escape route and inall rooms or areas that are of high fire risk to 3is a system incorporating detectors in allcirculating spaces that form the escape PDis a fire detection and fire alarmsystem intended for the protection of property and issub divided into two a system installed throughout a dwellingincorporating detectors in all rooms and areas inwhich a fire may start (excluding toilets, bathroom andshower rooms).PD2is a system incorporating detectors installedonly in rooms or areas of a dwelling in which the riskof fire to the property is judged to warrant 1 of the standard provides information on theminimum grade and category of fire detection and firealarm systems for the protection of life in typicaldwellings.

7 Illustrated below is a simplified version of some ofthe information from that table. Table 2 of the standard providesrecommendations for the minimum grade andcategory of system that should be installed for theprotection of property in typical dwellings. Illustratedis a simplified version of that and sharedhouses with no floorgreater than 200m2 Bungalow, flat or othersingle-storey unitMaisonette or owner-occupied two-storeyhouseThree-storey houseFour (or more) storeyhouseSingle-familydwellings and sharedhouses with one ormore floors greaterthan 200m2 Bungalow, flat or othersingle-storey unitMaisonette or two-storey houseThree (or more) storeyhouseGrade A, Category LD2, with detectors sited inaccordance with the recommendations of BS 5839-1for a Category L2 systemDWELLING CLASSNAPIT0870 444 1392 7fire alarm systemsfire alarm systemsDLD2 DLD2 DLD2 BLD2 FLD3 FLD3 DLD3 DLD2 DLD2 DLD2 DLD2 BLD2 New or materiallyaltered dwellingscomplying withGRADE CATEGORYGRADE CATEGORYGRADE CATEGORYE xisting dwellingscomplying withExisting dwellingswhere structuralfire precautionsare of a lowerstandard thanBS 5588-1 or guidance supporting BUILDING RegulationsDLD2 BLD2 DLD3 BLD2 DLD2 BLD2 Dwelling ClassGradeCategorySingle-storey and two-storey dwellingsCPD2 Other types of dwellingsA system conforming to the recommendations ofBS 5839-1 for a Category P1 systemIn the

8 Next issue of The Competent PersonI shallcontinue with types of fire detectors and theirinstallation.