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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 6 of 6 matching FAQs

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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
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
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 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