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Fire & Security FAQ Database

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Technical guidance only. Confirm current project requirements against the applicable standards, legislation, system documentation and site-specific fire strategy.

Showing 11 of 11 matching FAQs

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How should AOV (automatic opening vent) actuation be tested?

Trigger the mapped detection zone or control input and confirm the vent opens fully within the expected time, then closes/resets correctly. Check the manual override controls at the fire service access point, the standby supply, and that fault monitoring reports to a supervised location. Wind and weather interlocks can legitimately block a test — understand the control logic before recording a failure. Note travel times and any struggling actuators; they fail on the day they're needed, not on the bench. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS EN 12101AOV actuation
What do fire and security engineers need to know about IP networking?

Enough to be safe and useful: how the equipment gets its address (static vs DHCP), what a subnet is, how to ping a device, and how to check a link light before blaming the equipment. Get graphics terminals, gateways and remote monitoring onto documented addresses with the site's IT involved — undocumented static IPs cause outages years later. Never change network settings on shared infrastructure without the client's IT; a fire system that takes down a corporate VLAN is a bad day. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1IP networking
How should fire alarm defects be prioritised?

Judge each defect by its effect on the system's ability to detect and warn: anything that stops detection or alarm in an occupied area, or takes the panel or signalling down, needs immediate action and formal notification to the responsible person. Degraded redundancy, single-device faults and non-urgent wear items follow, with agreed timescales. Put the priority and the consequence in writing — clients act on "this means the second floor has no automatic detection" far faster than on a code. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1defect prioritisation
Why do detectors report dirty or drift warnings, and what should I do?

Optical chambers accumulate dust, insects, steam residue and decorating debris; the analogue value creeps up until the panel flags contamination or pre-alarm. Check the environment first — a detector near an air-handling vent or in a workshop will foul repeatedly no matter how often it's swapped. Clean or replace per the manufacturer's guidance (many heads are exchange-only), record the analogue values before and after, and note repeat offenders: a location that fouls every few months needs a detection-type review, not another clean. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsEN 54-7detector contamination
How are emergency lighting duration tests carried out?

Simulate mains failure for the rated duration and inspect every luminaire at the end — not the start — of the test, because failing batteries drop out late. Record failures by location, replace or repair, and re-test what was fixed. Schedule full-duration tests for times when the building can tolerate discharged batteries afterwards (they need recharge time before they can protect again). Short functional tests in between confirm operation but don't prove duration. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5266-1emergency lighting duration tests
How do I reduce false alarms on a fire alarm system?

Start with the event log, not opinions: identify which devices, times and conditions generate the unwanted alarms. Then match the fix to the cause — wrong detector type for the environment (steam, dust, cooking), detector siting too close to vents or kitchens, transient activities without temporary management, or genuine faults presenting as alarms. Multi-sensor or heat detection, relocation, cause-and-effect delays where the standard permits them, and client housekeeping all have their place. Change one thing at a time and monitor the log after each change so you know what actually worked. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1false alarm reduction
What do intruder alarm grades mean in practice?

The graded framework matches the system's resistance to the anticipated intruder skill level — higher grades demand more supervision, tamper security and signalling resilience. The grade is set by the risk assessment and, where relevant, insurer requirements, and it drives component selection and signalling: you can't mix a low-grade signalling path with a high-grade requirement and stay compliant. Check the current standard's edition and the insurer's spec before quoting or modifying a graded system. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS EN 50131intruder alarm grades
What does risk-based maintenance mean for fire alarm servicing?

Service effort is weighted by the risk profile of the site and the system's history rather than treated as a uniform checklist: a sleeping-risk premises or a site with recurring faults gets more attention than a low-occupancy unit with a clean record. The maintenance regime still has to meet the recommendations of the applicable standard and the site's fire strategy — risk-based means prioritising within that framework, not cutting visits below it. Document the reasoning so the regime can be defended. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1risk-based maintenance
What should a fire alarm service report actually say?

What you found, what you tested, what you changed, what remains outstanding, and what the client should do next — with device references and readings, not vague phrases. "Fault cleared" is only acceptable when the report shows the checks that prove it. Record impairments and isolations explicitly, get outstanding defects in writing to the responsible person, and keep the site history so recurring problems are visible across visits rather than rediscovered each time. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1service reporting
What should be verified when fire alarm systems control smoke dampers?

Prove the chain: alarm input → control output → damper movement → position feedback to the panel or BMS. Witness the damper actually travel where access allows, don't just trust the status LED. Check the fail-safe state matches the design (open or closed varies by strategy), and that damper faults report somewhere someone watches. Record which dampers were exercised — on large sites rotate through them across the maintenance programme with the ventilation contractor where needed. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1smoke damper control
How do I check sounder circuit loading?

Add up the alarm-state current of every sounder, beacon and VAD on the circuit from the datasheets — then compare against the circuit's rated output with the manufacturer's derating applied. Measure the actual current in full alarm where practicable; installations drift from their paperwork. An overloaded circuit may work on a bench-fresh PSU and fail on batteries at the end of the standby period, which is precisely when it matters. Fix by re-balancing circuits, not by hoping. Standards are referenced for orientation only — always confirm requirements against the current edition of the applicable standard, the site's fire strategy and manufacturer documentation.

GeneralAll systemsBS 5839-1sounder circuit loading