Fire alarm categories
In the UK fire alarm systems are categorised by application, with significantly different setups installed depending on the building, what is being safeguarded by the fire alarm and how the alarm itself operates.
The categories of fire alarm can be split into one of several types: M (manual), L (designed to protect life) and P (designed to protect property). Each of the latter categories has sub-categories specifying more precisely when they are to be used:
M – A manual system is the most basic of fire alarm types and relies on the occupants of a building being able to raise the alarm in the event of a fire. An example of a manual alarm would include a bell to ring that would warn other people in the building there was a fire. This type of system relies on there always being someone awake and alert to raise the alarm and is only suitable for some work situations.
UK fire alarm sub-categories
P1 – Automatic detection to protect buildings and minimise losses in the event of a blaze. Although this would be throughout the building, very small low-risk rooms (e.g. cupboards and toilets) may be excepted.
P2 – Automated fire detection to protect the building, but only in certain areas of the building designated as high-risk (e.g. where there are flammable materials or electrical equipment).
L1 – Automatic fire detection to safeguard life, with sensors throughout the building apart from minor exceptions. This system, also covering roof spaces and voids, will provide early warning to building occupants and would be particularly suitable for care homes etc.
L2 – Automated detection which is designed to protect life. Sensors are placed in high risk areas (e.g. kitchens), escape routes and rooms adjoining escape routes. Suitable for mid-sized premises where occupants are sleeping in the building and need to be alerted so that they can escape the fire.
L3 – Life protection alarm system where detectors are placed on the escape routes and in adjacent rooms, aimed to ensure the escape route is as clear as possible for occupants to be alerted and exit the building safely.
L4 – A category L4 alarm system offers detection for the escape route. Detectors might also be placed elsewhere in the building, but the priority is to keep the escape route clear.
L5 – This category is where custom solutions are required, generally when the building or application doesn’t fit into any of the other categories. The system might fit into L5 if there are specialist fire hazards present e.g. in a factory situation.