Life-safety systems
Smoke, heat & CO alarms
The alarm system fitted to a dwelling is graded under BS 5839-6. New-build and most rented properties in England need at minimum Grade D LD2 — mains-powered with battery back-up, interlinked, and covering escape routes plus the highest-risk rooms.
Grade & category — what the letters mean
Grade D
Mains-powered alarms with an integral tamper-proof standby battery. The minimum grade for most new and rented dwellings.
Category LD2
Detection in escape routes (halls, landings) and in rooms presenting a high fire risk (typically the living room / lounge, plus a heat alarm in the kitchen).
Typical Grade D LD2 layout
- Hall / landing on every storey: optical smoke alarm.
- Living room / principal habitable room: optical smoke alarm.
- Kitchen: heat alarm (not smoke — cooking causes nuisance alarms).
- All units interlinked — wired or wireless — so any alarm sets off every alarm.
- Supplied from a dedicated regularly-used lighting or independent circuit; separate battery back-up in every unit.
Carbon monoxide alarms
English rental law (Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022) requires landlords to fit a CO alarm in everyroom used as living accommodation that contains a fixed combustion appliance (excluding gas cookers). Alarms should meet BS EN 50291-1 and be sited to manufacturer's instructions — typically at head height and within 1–3 m of the appliance.
England, Wales, Scotland — key differences
- Scotland requires Grade D LD2 in every home (not just rentals) since February 2022 — the tightest regime in the UK.
- England & Wales — Grade D LD2 is required for new builds and rented properties; strongly recommended for owner-occupied.
- All jurisdictions require CO alarms in rooms with fixed solid-fuel or (in England from 2022) gas appliances.