Categories of fire alarm

Even in buildings with comprehensive fire detection, the provision of manual call points will still normally be of great value; people in the vicinity of a fire will normally be aware of the fire, and able to raise the alarm by use of a manual call point, before it is detected automatically.

If a fire alarm/wireless fire alarm is intended to fulfil the objectives of more than one Category of system, then the system needs to
comply with the recommendations for each of the Categories. For example, a fire alarm system whose sole purpose is to provide property protection throughout the building (a Category P1 fire system) might not need to give an alarm signal of sufficient audibility to rouse all occupants who might sleep in the building. If, however, the system
were also installed for the purpose of life safety (a Category L system), sufficient fire alarm sounders to rouse sleeping occupants would be necessary.

This part of BS 5839 does not recommend which Category of system needs to be installed in any given premises. The various system Categories need to be regarded as a “menu”, from which purchasers, users, specifiers, enforcing authorities, insurers or system designers may select a suitable system for any building. A fire risk assessment is advisable as this gives an assessment of the fire risk as to how the building is used and in operation.

Because of the wide range of fire alarm systems, including wireless fire alarm systems, covered by the recommendations of part of BS 5839, the specification of requirements for a system, by a purchaser, user, enforcing authority or insurer or fire risk assessment personnel, or the description of a system by a designer or installer, by reference to this standard, without a reference to system Category, will have little meaning. The Category of system to be installed always needs to be included in the specification. Similarly, the
specification of any Category of system, other than Category L1 or P1, always needs to include details of
those areas of the building that are to be protected.