BS 5839-1: commercial categories.
| Category | Coverage | Typical application |
|---|---|---|
| M | Manual call points and sounders only — no automatic detection | Simple, low-risk workplaces occupied by alert, awake people |
| L5 | Detection engineered for a specific objective/location | Bespoke risk solutions — e.g. protecting an inner room's escape |
| L4 | Escape routes: corridors and stairways | Minimum automatic cover where routes need early warning |
| L3 | Escape routes plus rooms opening onto them | Common commercial benchmark — warns before rooms make routes impassable |
| L2 | L3 plus defined high-risk rooms (kitchens, plant, sleeping areas) | The working standard for hotels and guest houses |
| L1 | Automatic detection throughout the building | Care homes, complex sleeping-risk and vulnerable-occupancy premises |
| P2 / P1 | Defined areas / whole building — for property protection | Insurer-driven; specified alongside an L category, not instead of one |
Categories describe detection coverage; the system behind them also needs zoning or addressable indication proportionate to the building, call points at exits, audibility throughout (75 dB(A) at the bedhead in sleeping premises), and VADs where occupants may not hear sounders.
BS 5839-6: dwellings and HMOs.
Part 6 splits the specification into hardware grade and coverage level:
| Grade | Hardware |
|---|---|
| A | Full system to Part 1 principles: control panel, detectors, call points — expected in larger and higher-risk HMOs |
| C | Detectors/sounders with central control equipment |
| D1 / D2 | Mains-powered interlinked alarms — D1 with tamper-proof standby supply (the standard specification), D2 with replaceable batteries |
| F1 / F2 | Battery-only alarms — generally inadequate for rented and licensed stock |
| Coverage | Detection located in |
|---|---|
| LD1 | All circulation spaces and all risk rooms — the sleeping-risk gold standard |
| LD2 | Circulation spaces plus specified high-risk rooms (kitchen, living room) — the common HMO benchmark |
| LD3 | Circulation/escape routes only — the legal floor for single dwellings, rarely sufficient in HMOs |
A typical licensing outcome for a two/three-storey shared HMO is Grade D1 LD2, escalating to Grade A in larger houses and bedsit conversions — the determination sits in the fire risk assessment and the LACORS-derived standards the council applies.
Testing and records.
- Weekly: user test from a call point (rotated), logged.
- Periodic servicing: by a competent contractor at intervals per BS 5839 recommendations — six-monthly is the norm for commercial systems — with inspection certificates retained.
- False alarm management: recurring unwanted alarms are a finding, not a nuisance — they drive occupant complacency and brigade-response consequences, and the assessment will require cause analysis.
These records are core evidence for the assessment, the auditing officer and the insurer alike — and alarm certificates are one of the documents people actually mean when they ask for a "fire certificate".