BS 5839-1:2025 Fire Detection and Fire Alarm Systems for Buildings

This flashcard set covers the key terminology, system categories, and technical requirements defined in the BS 5839-1:2025 code of practice for fire detection systems in non-domestic buildings.

Category M

Manual fire detection and fire alarm systems that incorporate no automatic fire detectors and rely on manual call points.

Category L

Automatic fire detection and fire alarm systems specifically intended for the protection of life.

Category L1

Systems installed throughout all areas of a building to offer the earliest possible warning of fire for the longest available escape time.

Category L2

Systems providing early warning in defined parts of a building, including sleeping areas and high fire hazard/risk rooms, in addition to L3 objectives.

Category L3

Systems installed in escape routes and rooms opening onto escape routes to allow occupants to exit before routes become impassable.

Category L4

Systems installed only within escape route circulation areas like corridors and stairways to enhance safety by detecting smoke.

Category L5

Custom systems designed to satisfy a specific fire safety objective, often localized or compensating for departures from normal guidance.

Category P

Automatic fire detection and fire alarm systems intended for the protection of property.

Category P1

Systems installed throughout all areas of a building to minimize the time between ignition and the arrival of firefighters.

Category P2

Systems installed only in defined parts of the building with high fire hazard levels or high risk to property/business continuity.

Alarm Receiving Centre (ARC)

A continuously staffed remote location where fire system information is displayed or recorded so that the fire and rescue service can be summoned.

Fire Detection Zone

A geographical subdivision of a building in which the occurrence of fire is indicated separately from other subdivisions.

Search Distance

The distance a searcher must travel within a zone to visually determine the position of a fire, limited to a maximum of 60m.

Maximum Alarm Load

The maximum power demand imposed on a system supply under fire conditions, including all sounders, detectors, and transmission equipment.

Phased Evacuation

A strategy where different parts of a building are evacuated in a controlled sequence, starting with those at the greatest risk.

Soak Period

A period of at least one week after commissioning, but before handover, where a system is monitored for false alarms and faults.

Standard Fire-Resisting Cable

Cables designed to survive for 30 minutes when tested under fire and water spray conditions (Class PH 30).

Enhanced Fire-Resisting Cable

Cables designed to survive for 120 minutes under fire and water spray conditions, required for complex phased evacuation or buildings over 30m.

Control and Indicating Equipment (CIE)

The central hardware that monitors circuits, supplies power, indicates fire or fault signals, and allows manual control of the system.

False Alarm

A fire alarm signal resulting from a cause other than fire, categorized as unwanted, equipment, malicious, or good intent.

Unwanted Fire Alarm Signal

A specific type of false alarm where an automatic fire detection signal is passed on to the fire and rescue service.

Zone Plan

A diagrammatic representation of the building showing entrances, circulation areas, and zone divisions, placed near the CIE.

Coincidence (Double Knock)

An arrangement where an alarm output is only triggered when at least two independent input signals are received simultaneously.