A house in multiple occupation (HMO) needs much more than a couple of battery smoke alarms. Councils expect a proper, interlinked fire detection system — so that a fire in one room sets off every alarm in the house. The system is described with two pieces of jargon from the British Standard BS 5839-6: a Grade and a Category.
🔧 Grades: How the System Is Built
The Grade tells you what kind of equipment it is and how it’s powered.
| Grade | What it is | Where you’ll see it |
|---|---|---|
| A | Separate detectors, sounders and a control panel, with manual call points and backup power | Larger HMOs, bedsit HMOs of 3+ storeys |
| C | Detectors and sounders on a common power supply with simple central control | Less common in HMOs |
| D1 | Mains-wired alarms with a sealed (tamper-proof) backup battery, interlinked | Most shared-house HMOs and rented homes |
| D2 | Mains-wired alarms with a user-replaceable backup battery | Owner-occupied homes; usually not enough for an HMO |
| F1 / F2 | Battery-only alarms (sealed / replaceable battery) | Not suitable on their own for an HMO |
The 2019 edition of BS 5839-6 (amended 2020) split the old Grade D and Grade F into “1” and “2” versions and dropped Grade E. If your installation certificate says plain “Grade D”, it was probably installed to the older standard.
📍 Categories: Where the Detectors Go
The Category tells you how much of the house is covered. “LD” means it’s there to protect lives.
| Category | Coverage |
|---|---|
| LD3 (minimum) | Escape routes only — hallways and landings |
| LD2 (medium) | Escape routes plus rooms where a fire is more likely to start — kitchen, living room, often bedrooms |
| LD1 (highest) | Every room where a fire could start, including bedrooms and cupboards — not bathrooms or toilets |
Kitchens get a heat alarm, not a smoke alarm, so cooking doesn’t cause constant false alarms. Smoke alarms go in hallways, landings, living rooms and bedrooms.
🏘️ What Does Your HMO Typically Need?
London councils base their HMO standards on BS 5839-6 and the national LACORS fire safety guidance, but the details differ from borough to borough. As a guide:
| Type of HMO | Typical system |
|---|---|
| Shared house (one group sharing, joint tenancy or rooms), 1–2 storeys | Grade D1, LD2: interlinked smoke alarms in hallways, landings and lounge, heat alarm in the kitchen |
| Shared house, 3–4 storeys | Grade D1, LD2 — many councils also want smoke alarms in every bedroom |
| Shared house, 5+ storeys | Grade A, LD2 with a control panel and call points |
| Bedsits (separate lets, cooking in rooms), 1–2 storeys | Grade D1 interlinked in common areas; interlinked heat alarm in each bedsit with cooking, plus its own smoke alarm |
| Bedsits, 3+ storeys | Grade A in the common areas, with alarms in each bedsit as above |
⚖️ What the Law Says
- HMO management regulations (2006): the manager must keep fire alarms and fire-fighting equipment in good working order.
- Licensed HMOs: licence conditions require a smoke alarm on every storey used as living accommodation and a CO alarm in any room with a fixed combustion appliance (such as a boiler), kept in working order — plus whatever fire system the council specifies.
- Fire risk assessment: the shared parts of an HMO fall under the Fire Safety Order 2005, so you need a fire risk assessment and must act on it.
- Housing Health and Safety Rating System: councils can take enforcement action if fire safety is inadequate — licensed or not — including improvement notices and fines.
📅 Testing, Servicing & Certificates
| What | How often |
|---|---|
| Press the test button / check all alarms sound together | At least monthly (many councils ask for weekly in HMOs) |
| Grade D1 system inspection and service | Every year, by a competent person |
| Grade A system service | Every 6 months, by a competent fire alarm engineer |
| Logbook of tests, faults and repairs | Keep it up to date — councils often ask to see it |
Keep two kinds of certificate: the installation and commissioning certificate from when the system was fitted, and a periodic inspection / servicing certificate each year (or every 6 months for Grade A). Councils commonly ask for both with a licence application or renewal.
🏆 HMO Fire Alarms with FE Maintenance
- All HMO fire alarm systems — from interlinked Grade D1 alarms to Grade A panel systems — installed, tested and serviced by us to BS 5839, with the certificates your council asks for
- Maintenance visits on the schedule your system needs: yearly for Grade D1, every 6 months for Grade A
- Gas safety, EICR and PAT for the same HMO, all done on the same day
- Free online client portal — every certificate stored in one place, with expiry alerts. See how it works
We cover North, West and Central London. See our fire alarm service or read our HMO certificates guide.
General information based on BS 5839-6:2019+A1:2020, the Management of Houses in Multiple Occupation (England) Regulations 2006 and published London council HMO standards, as of October 2026. Requirements vary by council — always check your local HMO standards and licence conditions. Not legal advice.
Frequently Asked Questions
Need an HMO Fire Alarm Installed or Serviced?
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