Fire Detection & Alarm Systems

A fire detection and alarm system detects fire, warns occupants, calls the fire brigade and drives the building's fire responses. It comprises detectors and manual call points; the fire indicator or control panel; occupant warning, from simple sounders to emergency warning and intercommunication systems (EWIS) with voice messages and wardens' phones; alarm signalling to a monitoring centre or brigade; and the interfaces that shut down or switch air handling to fire mode, home lifts, release doors, start smoke control and signal sprinkler and suppression status.

Systems are conventional (detectors grouped in zones, so the panel knows only the zone) or addressable (each device reported individually, with drift compensation and fault reporting). Large buildings network several panels. What a system must include depends on building class and height under each jurisdiction's building code; what it must do in an alarm is set out in the cause-and-effect matrix, which is the document most often out of date.

What shortens life:

• Contamination: dust, steam, insects and construction dust drift detectors toward false alarms.
• Fit-outs that cover, remove, relocate or add detectors and change zones without reprogramming.
• Panel obsolescence that stops the system being extended or reprogrammed.
• Neglected batteries in panels and EWIS.
• Building works during which detectors are covered or zones isolated and never restored.

Panel obsolescence

A panel keeps passing its routine tests until the day it cannot be repaired, extended or reprogrammed because its maker no longer supports it. That day usually comes with a tenancy change: a fit-out needs new devices and new cause-and-effect programming, and the panel cannot take them. Unsupported panels are therefore end of life whatever their test results.

False and unwanted alarms

Contaminated detectors, the wrong detector type for the space (smoke detectors in kitchens and near showers), cooking, steam, dust from works, and insects cause unwanted alarms. Brigades charge for repeated unwanted alarms in many jurisdictions; occupants learn to ignore alarms; and the response to repeated false alarms is often to isolate zones, which leaves areas unprotected.

Isolations and covered detectors

Detectors are covered and zones isolated during building works and cleaning, then forgotten. A building can run for months with floors effectively unprotected. Addressable panels show isolations; the question is whether anyone reads them.

Coverage gaps

Fit-outs add rooms, partitions, ceilings and voids without adding detectors; concealed spaces above ceilings and below floors are left unprotected where required; detectors end up too close to air supply diffusers, which blow smoke away from them.

Cause-and-effect drift

Over the years the interfaces the panel drives change: air handling units replaced, lifts modernised, access control upgraded, smoke control added. Unless the cause-and-effect matrix and interfaces are updated and tested together, lifts do not home, doors do not release, and smoke control does not start in a real fire.

Occupant warning failures

Sounders and speakers that are inaudible in parts of the building, EWIS amplifiers with failed batteries, and messages that are unintelligible in noisy or reverberant spaces leave occupants unwarned.

Alarm signalling failures

Alarm signalling equipment that dials out over a copper line stops working when the line is retired; monitoring contracts lapse; dual-path signalling is reduced to one path. The panel alarms locally but nobody is called.

Domestic alarm failures

Smoke alarms in dwellings are removed, painted over, disconnected after nuisance alarms, or simply past their ten-year life; interconnection between alarms fails; tenancies change without checks.

At the panel

• Panel make, model and age; vendor support status.
• Faults, isolations and disabled devices on the display or event log.
• Battery dates; standby charge indication.
• Zone block plan or graphics matching the building as it now is.
• Logbook entries for tests, faults and false alarms.

In the building

• Detectors covered with caps, bags or tape; painted detectors.
• Rooms and voids without detectors; detectors next to supply diffusers.
• Smoke detectors in kitchens, bathrooms and dusty areas.
• Call points obstructed or missing at exits.
• Sounders and speakers absent from new rooms.
• Domestic alarms missing, beeping or dated more than ten years ago.

In the records

• Routine service records at each required frequency.
• Annual fire safety statement or essential safety measures report.
• Unwanted alarm history and brigade charges.
• Cause-and-effect matrix and the last full interface test.
• Alarm signalling contract and the line or network it uses.
• Fire engineering report or fire strategy.

Findings are graded by what they demand: safety (can hurt someone now), failure (failed and damaging the building), condition (distress present and progressing), lifecycle (renewal due on age and exposure), deadline (a regulator or ordinance sets the date), check (investigate before sizing works) and nil (cosmetic or stable).

A fire services engineer or fire safety consultant leads, with the maintenance contractor and, for complex buildings, a fire engineer.

• Records review: service records against the required frequencies, annual statements, event logs, unwanted alarm history, cause-and-effect matrix, fire strategy and any performance solutions.
• Panel inspection: make, model, firmware, vendor support, spare capacity, isolations, faults, battery age and standby test.
• Coverage survey against the current layout, including ceiling and floor voids where detection is required, detector types against spaces, and call points at exits.
• Detector sampling: sensitivity and contamination readings from the panel for addressable systems; functional tests of a sample.
• Occupant warning test: sound levels and, for voice systems, speech intelligibility in representative spaces.
• Signalling test end to end with the monitoring centre, and identification of the communication path.
• Full integrated test of the cause-and-effect matrix with every interface operating: air handling, smoke control, lifts, doors, sprinkler and suppression signals.
• Domestic alarms: type, power, interconnection and age in a sample of dwellings, or all where the law requires.

The report should state compliance, coverage gaps, unwanted alarm causes, interface results, signalling path, panel support status, and a plan for repair or replacement.

• Restore protection: remove covers, clear isolations, and manage future isolations through a permit and daily check.
• Reduce unwanted alarms: right detector for each space (heat or multi-sensor in kitchens and near bathrooms), clean or replace contaminated detectors, relocate detectors away from diffusers, and manage hot works.
• Coverage additions after fit-outs, designed to the standard, with the zone plan and graphics updated.
• Cause-and-effect update and full integrated testing whenever any interfaced system changes.
• Panel replacement with a supported addressable system, reusing compatible cabling where possible, with temporary protection during changeover.
• Detector replacement programme on age, by floor or zone.
• Occupant warning upgrade: additional sounders or speakers, or a voice system where intelligibility is required.
• Signalling upgrade to supported, preferably dual-path, communications before copper lines are retired.
• Domestic alarms: interconnected photoelectric alarms, hard-wired or with ten-year sealed batteries, where required.

Routine servicing and annual certification are recurring contracts. Detector replacement is priced per device. Coverage additions per device, with design and reprogramming. Panel replacement is a lump-sum project including the panel, reprogramming, interfaces, commissioning and full integrated testing, with temporary fire watch or temporary panels during changeover. Signalling upgrades are a lump sum plus a recurring monitoring fee. Unwanted alarm charges are an operating cost that the remedies reduce.

Servicing, rectification and signalling are code compliance; detector and panel replacement are lifecycle; the integrated test is the check line that sizes the rest.

• Australia. The National Construction Code sets required detection and warning by building class; AS 1670.1 covers detection system design, AS 1670.4 emergency warning and intercommunication, and AS 1851 routine service at monthly, six-monthly and yearly frequencies. Systems are essential safety measures with annual certification (the Annual Fire Safety Statement in New South Wales and the annual essential safety measures report in Victoria). Brigades charge for unwanted alarms. Queensland requires interconnected photoelectric smoke alarms in all dwellings by 1 January 2027.
• United Kingdom. The Regulatory Reform (Fire Safety) Order 2005 places duties on the responsible person; BS 5839-1 covers non-domestic systems (weekly call point tests and periodic servicing, with every device tested annually), BS 5839-6 dwellings and BS 7273 interfaces; the Building Safety Act 2022 and Fire Safety (England) Regulations 2022 add duties for higher-risk residential buildings. Rented homes must have smoke alarms under the smoke and carbon monoxide alarm regulations.
• United States. NFPA 72 governs installation, inspection and testing, including annual functional testing of initiating devices and periodic smoke detector sensitivity testing; NFPA 101 and the International Fire Code set where systems are required; NFPA 4 covers integrated system testing; many jurisdictions charge for false alarms.

• Routine service records for the last twelve months against the required frequencies.
• Current annual fire safety statement or essential safety measures report, with any qualifications.
• Panel make, model, firmware and vendor support status.
• Event log extract showing faults, isolations and unwanted alarms.
• Cause-and-effect matrix and the latest full integrated test report.
• Alarm signalling contract and communication path.
• Zone block plan and as-built drawings.
• Fire strategy or fire engineering report, and any performance solutions.
• Domestic smoke alarm records for residential buildings.