BS 5839-1 is the code of practice for fire detection and alarm systems in non-domestic premises. It groups systems into categories according to their purpose: protecting life (L), protecting property (P), or manual-only systems (M). Your fire risk assessment determines which category you need.
The categories
| Category | Coverage | Typical use |
|---|---|---|
| M | Manual call points only, no automatic detection | Small, low-risk workplaces where people are awake and alert |
| L1 | Automatic detection throughout the building | Care homes, hospitals, high-risk sleeping premises |
| L2 | Escape routes plus defined high-risk rooms | Hotels, buildings with specific high-risk areas |
| L3 | Escape routes plus rooms opening onto them | Many offices and multi-occupied buildings |
| L4 | Escape routes only (corridors, stairways) | Simple, low-risk premises |
| L5 | Bespoke coverage to meet a specific objective | Where the risk assessment identifies a particular need |
| P1 | Property protection throughout | Warehouses, heritage buildings, insurer-driven |
| P2 | Property protection in defined areas | High-value or high-risk rooms such as server rooms |
Homes and HMOs: BS 5839-6
Dwellings, including many HMOs and sheltered housing, follow BS 5839-6. It uses grades for the type of equipment (for example Grade A panel systems, Grade D1 and D2 mains-powered interlinked alarms with battery backup, and Grade F battery alarms) and categories LD1, LD2 and LD3 for the extent of coverage. See the HMO checklist for typical arrangements.
Testing and servicing
- Weekly: test a different manual call point each week and record it in the log book
- Every six months (maximum): periodic inspection and servicing by a competent engineer
- After alterations: check the category still matches the layout and risk
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