Definitions
Conventional Fire Alarm These systems are traditionally installed in small offices and commercial premises. Normally no more than 8 zones, they require a cable for each fire alarm zone and fire alarm sounder
Two Wire System These systems are again normally no more than 8 zones and require less cabling as the sounders and detectors can be combined in one housing. This makes them very useful for small hotels and guest houses
Analogue Addressable Systems Reserved for very large premises, each detection device and siren are fully programmable, enabling easy tracing of faults and activations. They require a single loop of cable, making them easy to install.
Wireless Systems These systems are extremely useful for premises for which it would be very costly or impossible to close parts during installation, eg. Large hotels
Alarm systems must conform to the current British Standard, which is BS5839
Under these regulations, all systems should be graded as follows:
L - Life Protection
P - Property Protection
M - Manually operated systems ie. Fire alarm call points All automatic fire alarm systems require manual call points
These definitions are further divided as follows:
L1 - Automatic detection installed in all areas of a building. Typically used in nursing homes or hospitals
L2 - Automatic detection installed in high risk areas, eg. Kitchen, exit routes, corridors and adjoining rooms. Typically used in hotels, guest houses and multi-storey buildings
L3 - Automatic detection installed in exit routes, corridors and adjoining rooms Typically used in multi-storey buildings
L4 - Automatic detection installed in exit routes, corridors. Typically used in offices and small commercial buildings
L5 - Automatic detection installed as determined by a specialist fire risk assessor
P1 - Automatic detection installed in all areas
P2 - Automatic detection installed where required
Noise Levels Normal alarm siren noise levels must not be below 65 decibels. However, if a person is likely to be sleeping on the property, the noise levels must be a minimum of 75 decibels at the bed head. As a fire door absorbs a surprising amount of noise, this normally requires a fire alarm siren to be installed in each individual bedroom
Definitions above are only meant as a guide. The exact specification of equipment required for a premise should only be determined after consultation with a qualified fire risk assessor
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