Fire Alarm Categories

 Category Type M

Category Type M systems are Manual systems (Call Points Only) and therefore, incorperate no automatic fire detectors.

Category Type L

Category Type L systems are Automatic Fire Detection systems intended for the protection of life. They are further subdivided into:

Category L1:

Systems installed throughout all areas of the building. The objective of a Category L1 system is to offer the earliest possible wardning of fire, so as to achieve the longest available time for escape.

Category L2:

Systems installed only in defined parts of the building. A Category L2 systm should include the coverage necessary to satisfy the recommendations of this standard for a Category L3 system; the objective of a Category L2 system is identical to that of a Category L3 system, with the additional objective of affording early warning of fire in specific areas of high fire hazzard level and/or high fire risk.

Category L3:

Systems designed to give a warning of fire at an early enough stage to enable all occupants, other than possibly in the room of the fire origin, to escape safely, before the escape routes are impassable owing to the presence of fire, smoke or toxic gases; NOTE To achieve the above objective it will normally be necessary to install detectors in rooms which open onto an escape route, circulation spaces, such as corridors and stairwells.

Category L4

Systems are designed to enhance the safety of occupants by providing warning of smoke within escape routes; NOTE the installation of detectors in additional areas is not precluded, and the system could then still be regarded as a Category L4 system.

 Category L5:

A systems in which the protected area(s) and/or location of detectors is designed to satisfy a specific fire safty objective (other than that of a Category L1, L2, L3 or L4 system). Often, the design is based on a localised need for fire detection in only part of a building. Protection might be provided to compensate for some departure from normal guidance elsewhere or as a part of the operating system for a fire protection system. Such a system could be as simple as one that incorperates a single automatic fire detector in one room (in wwhich outbreak of a fire would create undue risk to occupants, either in the room or elsewhere in the building), but the system could comprise comprhensive detection throughout large areas of a building in which, for example, structural fire resistance is less than normally specifies for building of that type: NOTE  the protection afforded by a Category L5 system might, or might not incorporate that provided by a Category L2, L3 or L4 system,