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There are many types of fire alarm systems each suited to different building
types and applications. A fire alarm system can vary dramatically in both price
and complexity, from a single panel with a detector and sounder in a small comercial property
to an addressable fire alarm system in a multi-occupancy building. As can be
seen from this example these systems have to protect both buildings and occupants.
The categories of fire alarm systems are L if they are designed to protect
life, P to protect buildings and M if they are manual systems.
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M Fire Alarm System
Manual systems e.g. hand bells, gongs etc. These may be purely manual
or manual electric, the latter may have call points and sounders. They
rely on the occupants of the building discovering the fire and acting
to warn others by operating the system. Such systems form the basic requirement
for places of employment with no sleeping risk. |
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P1 Fire Alarm System
The system is installed throughout the building - the objective being
to call the fire brigade as early as possible to ensure that any damage
caused by fire is minimised. Small low risk areas can be excepted, such
as toilets and cupboards less than 1m². |
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P2 Fire Alarm System
Detection should be provided in parts of the building where the risk
of ignition in high and/or the contents are particularly valuable. Category
2 systems provide fire detection in specified parts of the building where
there is either high risk or where business disruption must be minimised. |
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L1 Fire Alarm System
A category L1 system is designed for the protection of life and which
has automatic detectors installed throughout all areas of the building
(including roof spaces and voids)with the aim of providing the earliest
possible warning. A Category L1 system is likely to be appropriate for
the majority of residential care premises. In practice detectors should
be placed in nearly all spaces and voids. With category 1 systems, the whole of
a building is covered apart from minor exceptions. |
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L2 Fire Alarm System
A category L2 system designed for the protection of life and which has
automatic detectors installed in escape routes, rooms adjoining escape
routes and high hazard rooms. In a medium sized premises (sleeping no
more than ten residents) a category L2 system is ideal. These fire alarm
systems are identical to an L3 system but with additional detection in
an area where there is a high chance of ignition e.g. kitchen) or where
the risk to people is particularly increased (e.g. sleeping risk). |
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L3 Fire Alarm System
This category is designed to give early warning to everyone. Detectors
should be placed in all escape routes and all rooms that open onto escape
routes. Category 3 systems provide more extensive cover than category
4. The objective is to warn the occupants of the building early enough
to ensure that all are able to exit the building before escape routes
become impassable. |
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L4 Fire Alarm System
Category 4 systems cover escape routes and circulation areas only. Therefore,
detectors will be placed in escape routes, although this may not be suitable
depending on the risk assessment or if the size and complexity of a building
is increased. Detectors might be sited in other areas of the building,
but the objective is to protect the escape route. |
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L5 Fire Alarm System
This is the ‘all other situations’ category e.g. computer
rooms which may be protected with an extinguishing system triggered by
automatic detection. Category 5 systems are the ‘custom’ category
and relate to some special requirement that cannot be covered by any other
category. |
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