On Mon, 17 Sep 2018 23:21:58 +0200, Brian Reay wrote:
There are different types, at least 3, of detectors which are
recommended for different rooms/areas for just the reasons you say.
Placing the right one in the right location/checking it has been done is
the kind of thing I'd expect a competent Building Inspector to be able
to do. May be a call to the local council?
All a building inspector will do is point you Volume 1 of Part B of
the Building Regulations
https://www.gov.uk/government/public...ved-document-b
which says :-
Positioning of smoke and heat alarms
1.10 Detailed guidance on the design and installation of fire
detection and alarm systems in dwellinghouses is given in BS
5839-6:2004. However, the following guidance is appropriate
to most common situations.
1.11 Smoke alarms should normally be positioned in the circulation
spaces between sleeping spaces and places where fires are most
likely to start (e.g. kitchens and living rooms) to pick up smoke in
the early stages of a fire.
1.12 There should be at least one smoke alarm on every storey of a
dwellinghouse.
1.13 Where the kitchen area is not separated from the stairway or
circulation space by a door, there should be a compatible interlinked
heat detector or heat alarm in the kitchen, in addition to whatever
smoke alarms are needed in the circulation space(s).
1.14 Where more than one alarm is installed they should be linked so
that the detection of smoke or heat 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.
1.15 Smoke alarms/detectors should be sited so that:
a. there is a smoke alarm in the circulation space within 7.5m of the
door to every habitable room;
b.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 c.
the sensor in ceiling-mounted devices is between 25mm and 600mm below
the ceiling (25-150mm in the case of heat detectors or heat alarms).
Note: This guidance applies to ceilings that are predominantly flat
and horizontal.
1.16 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 or any
other opening between floors.
1.17 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.
1.18 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.
Power supplies
1.19 The power supply for a smoke alarm system should be derived from
the dwellinghouse’s mains electricity supply. The mains supply to the
smoke alarm(s) should comprise a single independent circuit at the
dwellinghouse’s main distribution board (consumer unit) or a single
regularly used local lighting circuit. This has the advantage that the
circuit is unlikely to be disconnected for any prolonged period. There
should be a means of isolating power to the smoke alarms without
isolating the lighting
1.20 The electrical installation should comply with Approved Document
P (Electrical safety).
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 except in large houses (BS
5839-6:2004 specifies fire resisting cables for Grade A and B
systems). Any conductors used for interconnecting alarms (signalling)
should be readily distinguishable from those supplying mains power,
e.g. by colour coding.
Note:
Mains-powered smoke alarms may be interconnected using radio-links,
provided that this does not reduce the lifetime or duration of any
standby power supply below 72 hours. In this case, the smoke alarms
may be connected to separate power circuits (see paragraph 1.19)
1.22 Other effective options exist and are described in BS 5839-1:2002
and BS 5839-6:2004. For example, the mains supply may be reduced
to extra low voltage in a control unit incorporating a standby
trickle-charged battery, before being distributed at that voltage to
the alarms.
Design and installation of systems
1.23 It is essential that fire detection and fire alarm systems are
properly designed, installed and maintained. Where a fire alarm system
is installed, an installation and commissioning certificate should be
provided. Third party certification schemes for fire protection
products and related services are an effective means of providing the
fullest possible assurances, offering a level of quality, reliability
and safety.
1.24
A requirement for maintenance cannot 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). See
paragraph 0.11.
Note:
BS 5839-1 and BS 5839-6 recommend that occupiers should receive the
manufacturers’ instructions concerning the operation and maintenance
of the alarm system.