Fire Safety Building Regulations

Means Of Warning And Escape

An Approved Document, which takes effect on 1 July 2000, dealing with the following Requirement from Part B of Schedule 1 to the Building Regulations 1991.

Fire Alarm And Fire Detection Systems

Introduction

1.1 Provisions are made in this section for suitable arrangements to be made in all buildings to give early warning in the event of fire.............

Dwellings (1.2 - 1.4 )

General

• 1.2 In most houses the installation of smoke alarms or automatic fire detection and alarm systems, can significantly increase the level of safety by automatically giving an early warning of fire.

• 1.3 If houses are not protected by an automatic fire detection and alarm system in accordance with the relevant recommendations of BS 5839: Part 1 Fire detection and alarm systems for buildings, Code of practice for system design, installation and servicing to at least an L3 standard, or BS 5839: Part 6 Code of practice for the design and installation of fire detection and alarm systems in dwellings to at least a Grade E type LD3 standard, they should be provided with a suitable number of smoke alarms installed in accordance with the guidance in paragraphs 1.4 to 1.22 below.

• 1.4 The smoke alarms should be mains-operated and conform to BS 5446 Components of automatic fire alarm systems for residential premises, Part 1 Specification for self-contained smoke alarms and point-type smoke detectors.

  They may have a secondary power supply such as a battery (either rechargeable or replaceable) or capacitor. More information on power supplies is given in clause 13 of BS 5839: Part 6: 1995.

  Note: BS 5446: Part 1 covers smoke alarms based on ionization chamber smoke detectors and optical (photo-electric) smoke detectors.

  The different types of detector respond differently to smouldering and fast flaming fires. Either type of detector is generally suitable.

  However, the choice of detector type should, if possible, take into account the type of fire that might be expected and the need to avoid false alarms.

  Optical detectors tend to be less affected by low levels of ‘invisible’ smoke that often cause false alarms.

  BS 5839: Part 6 suggests that, in general, optical smoke alarms should be installed in circulation spaces such as hallways and landings, and ionization chamber based smoke alarms may be the more appropriate type in rooms, such as the living room or dining room where a fast burning fire may present a greater danger to occupants than a smouldering fire.

• 1.5 A house may be regarded as large if any of its storeys exceed 200SqM.

• 1.6 A large house of more than 3 storeys (including basement storeys) should be fitted with an L2 system as described in BS 5839: Part 1: 1988, except that the provisions in clause 16.5 regarding duration of the standby supply need not be followed.

  However with unsupervised systems, the standby supply should be capable of automatically maintaining the system in normal operation (though with audible and visible indication of failure of the mains) for 72 hours, at the end of which sufficient capacity remains to supply the maximum alarm load for at least 15 minutes.

• 1.7 A large house of no more than 3 storeys (including basement storeys) may be fitted with an automatic fire detection and alarm system of Grade B type LD3 as described in BS 5839: Part 6 instead of an L2 system.

• 1.8 Where a loft in a one or two storey house is converted into habitable accommodation, an automatic smoke detection and alarm system based on linked smoke alarms should be installed (see paragraph 2.26).

• 1.9 The same principles apply within flats and maisonettes as for houses, while noting that:

  1. the provisions are not intended to be applied to the common parts of blocks of flats and do not include interconnection between installations in separate flats;
  2. a flat with accommodation on more than one level (ie a maisonette) should be treated in the same way as a house with more than one storey.

  Note: Some student residential accommodation is constructed in the same way as a block of flats. Where groups of students share one flat with its own entrance door, it is appropriate to provide an automatic detection system within each flat. In student flats constructed on the compartmentation principles for flats in Section 9 (B3), the automatic detection system will satisfy the requirements of building regulations if it gives a warning in the flat of fire origin. Where a general evacuation is required, the alarm system should follow the guidance in paragraph 1.30.

• 1.10 The detection equipment in a sheltered housing scheme with a warden or supervisor, should have a connection to a central monitoring point (or central alarm relay station) so that the person in charge is aware that a fire has been detected in one of the dwellings, and can identifythe dwelling concerned. These provisions are not intended to be applied to the common parts of a sheltered housing development, such as communal lounges, or to sheltered ccommodation in the Institutional or Other residential purpose groups.

• 1.11 Smoke alarms should normally be positioned in the circulation spaces between sleeping spaces and places where fires are most likely to start (eg kitchens and living rooms) to pick up smoke in the early stages, while also being close enough to bedroom doors for the alarm to be effective when occupants are asleep.

• 1.12 In a house (including bungalows) there should be at least one smoke alarm on every storey.

• 1.13 Where more than one smoke alarm is installed they should be linked so that the detection of smoke by one unit operates the alarm signal in all of them. The manufacturers’ instructions about the maximum number of units that can be linked should be observed.

• 1.14 Smoke alarms should be sited so that:

  1. there is a smoke alarm in the circulation space within 7.5m of the door to everyhabitable room;
  2. where the kitchen area is not separated from the stairway or circulation space by a door, there should be a compatible interlinked heat detector in the kitchen, in addition to whatever smoke alarms are needed in the circulation space(s);
  3. they are ceiling mounted and at least 300mm from walls and light fittings (unless in the case of light fittings there is test evidence to prove that the proximity of the light fitting will not adversely affect the efficiency of the detector). Units designed for wall mounting may also be used provided that the units are above the level of doorways opening into the space, and they are fixed in accordance with manufacturers’ instructions; and
  4. the sensor in ceiling mounted devices is between 25mm and 600mm below the ceiling (25-150mm in the case of heat detectors).

  Note: This guidance applies to ceilings that are predominantly flat and horizontal.

• 1.15 It should be possible to reach the smoke alarms to carry out routine maintenance, such as testing and cleaning, easily and safely. For this reason smoke alarms should not be fixed over a stair shaft or any other opening between floors.

• 1.16 Smoke alarms should not be fixed next to or directly above heaters or air conditioning outlets. They should not be fixed in bathrooms, showers, cooking areas or garages, or any other place where steam, condensation or fumes could give false alarms.

  Smoke alarms should not be fitted in places that get very hot (such as a boiler room), or very cold (such as an unheated porch). They should not be fixed to surfaces which are normally much warmer or colder than the rest of the space, because the temperature difference might create air currents which move smoke away from the unit.

  A requirement for maintenance can not be made as a condition of passing plans by the Building Control Body. However the attention of developers and builders is drawn to the importance of providing the occupants with information on the use of the equipment, and on its maintenance (or guidance on suitable maintenance contractors).

  Note: BS 5839: Part 1 and Part 6 recommend that occupiers should receive the manufacturers’ instructions concerning the operation and maintenance of the alarm system.

  System classifications

• 1.17 The power supply for a smoke alarm system should be derived from the dwelling’s mains electricity supply................If alarm comprises no stand by power supply, [ie AC ONLY] no other electrical equipment should be connected to this circuit. [ie AC only alarms, must only be wired back to main consumer unit on dedicated circuit].
• 1.18 A smoke alarm, or smoke alarm system, that includes a standby power supply or supplies, [ie AC with battery back up], can operate during mains failure. It can therefore be connected to a regularly-used local lighting circuit. ...............
• 1.19 Devices for monitoring ...............

  ...............If a continuous audible warning is given, it should be possible to silence it.

• 1.20 The smoke alarm circuit should preferably not be protected by any residual current device (rcd). However if ...............
• 1.21 Any cable suitable for domestic wiring may be used for the power supply and interconnection to smoke alarm systems. It does not need any particular fire survival properties. ...............

  Note: Smoke alarms may be interconnected using radio-links, provided that ..............

Please Note:

The above are only extracts taken 21st April 2001 and shown for information only select the link above each section for an un-edited version

The full version ( date 21st April 2001 ) an Acrobat PDF file can be downloaded from our site

The Requirement B1: Means of Warning and Escape: Section 1: Fire Alarm and Fire Detection Systems.........44kb

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