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Fire Safety Guide — Blocks of Flats

Do Blocks of Flats Need Fire Alarms in Communal Areas?

By Sebastian Grabowski, Managing Director — fire and security systems for residential blocks across Bedfordshire, Hertfordshire and London since 2010. Updated June 2026.

One of the most misunderstood questions in residential fire safety. The answer surprises most landlords and managing agents: in a purpose-built block with a stay-put strategy, a communal fire alarm is usually the wrong thing to install.

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Quick answer

Usually no. Purpose-built blocks of flats designed for a stay-put strategy should normally not have a communal fire alarm system — national guidance advises against it because it undermines stay-put and breeds false-alarm complacency. Each flat needs its own BS 5839-6 detection instead. Communal detection is needed where it operates smoke vents (AOVs), in converted houses without proper compartmentation, and in buildings moved to simultaneous evacuation. Your fire risk assessment makes the call.

Building by Building

What Does Your Building Actually Need?

The right answer depends on how the building was constructed and what evacuation strategy its fire risk assessment supports.

Purpose-built block, stay-put strategy

Usually NO communal alarm

Purpose-built blocks rely on compartmentation — each flat is a fire-resisting box. National guidance for purpose-built blocks of flats specifically advises against communal fire alarm systems where a stay-put strategy applies, because a sounding alarm encourages everyone to evacuate into the very escape routes the strategy keeps clear, and repeated false alarms breed dangerous complacency.

Block with smoke ventilation (AOV)

Detection only — no sounders

Many blocks have smoke detectors in corridors and lobbies that exist solely to trigger automatic opening vents (AOVs) and keep escape routes clear of smoke. This is a smoke control system, not a fire alarm — it operates silently with no sounders, and residents are often unaware it exists. It must still be maintained.

Converted house (pre-1991 conversion)

YES — mixed system common

Houses converted into flats that don't meet modern Building Regulations standards often cannot rely on compartmentation. Housing fire safety guidance (LACORS) typically calls for a BS 5839-6 Grade A mixed system: smoke detection in communal areas and heat detectors in each flat, sounding throughout the building so all residents evacuate together.

Simultaneous evacuation building

YES — and possibly BS 8629

Where a fire risk assessment has moved a building from stay-put to simultaneous evacuation — common where cladding or compartmentation defects are found — an interlinked alarm system covering all flats and communal areas is needed (it replaces waking watches under NFCC guidance). New residential buildings over 18m in England also require a BS 8629 evacuation alert system for fire service use.

The deciding document: your fire risk assessment

Whether a block needs communal detection is not a matter of opinion or habit — it follows from the building's construction, compartmentation and evacuation strategy, all assessed in the fire risk assessment required under the Regulatory Reform (Fire Safety) Order 2005 (as clarified by the Fire Safety Act 2021). If your assessment is out of date, or a contractor has proposed a communal alarm without reference to it, get the assessment reviewed first. We carry out PAS 79-2 fire risk assessments for residential blocks and install whatever the assessment actually calls for — including detection-for-AOV systems, Grade A mixed systems in conversions, and BS 8629 evacuation alert systems.

FAQs

Communal Fire Alarms in Flats — Frequently Asked Questions

Do blocks of flats need fire alarms in communal areas?
Usually not. In a purpose-built block of flats designed for a stay-put strategy, national fire safety guidance advises against installing a communal fire alarm system — each flat is built as a fire-resisting compartment, and a communal alarm would prompt unnecessary full evacuations and false-alarm complacency. Communal detection is normally only needed to operate smoke vents (AOVs), in converted buildings, or where the building has moved to a simultaneous evacuation strategy.
What is a stay-put policy in a block of flats?
Stay put means that if a fire breaks out in another flat or in a communal area, residents not directly affected are safer remaining in their own flats with doors closed than evacuating through potentially smoke-filled corridors. It relies on each flat being a 60-minute fire-resisting compartment. Residents in the flat where the fire started, or anyone affected by smoke or heat, should always leave and call 999.
Why is a communal fire alarm a bad idea in a stay-put building?
Three reasons: it contradicts the evacuation strategy by sounding throughout the building and pushing all residents into escape routes at once; false alarms (cooking, steam, vaping) quickly teach residents to ignore it; and mass evacuation can obstruct fire crews arriving to fight the fire. This is why guidance for purpose-built blocks of flats specifically recommends against communal alarm systems where stay-put applies.
What smoke detection is required inside each individual flat?
Each flat needs its own detection to BS 5839-6 — for new-build flats that means mains-powered interlinked alarms with battery back-up (Grade D1), typically smoke alarms in hallways and living rooms and a heat alarm in the kitchen (Category LD2). Detection inside the flat protects the people in it; it does not and should not sound in neighbouring flats in a stay-put building.
What are the smoke detectors in our corridors for, if not a fire alarm?
Almost certainly to operate the smoke control system. Detectors in corridors and lobbies trigger automatic opening vents (AOVs) at the head of stairs or in corridor walls, clearing smoke from escape routes so residents and firefighters can use them. These detectors operate vents silently — no sounders — and many residents never realise the system exists. It still requires regular maintenance.
Do converted flats need a communal fire alarm?
Often yes. Houses converted into flats — particularly conversions done before the 1991 Building Regulations — frequently lack proper compartmentation between flats. LACORS housing fire safety guidance typically recommends a BS 5839-6 Grade A mixed system: smoke detection in the communal stairway and escape routes plus heat detectors in each flat, all sounding together so the whole building evacuates simultaneously.
What is a BS 8629 evacuation alert system?
BS 8629 covers evacuation alert systems installed for the fire and rescue service — not for residents or the responsible person to use. The fire service can trigger sounders flat-by-flat or floor-by-floor if it decides to evacuate part of the building during an incident. Since December 2022, Approved Document B requires them in new residential buildings over 18 metres in England. They are entirely separate from any communal detection.
When does a block of flats switch to simultaneous evacuation?
When the fire risk assessment concludes the building can no longer support stay-put — most commonly because of combustible cladding, failed compartmentation, or serious fire-stopping defects. An interlinked temporary or permanent alarm system covering flats and communal areas is then installed so every resident hears a warning, in line with NFCC guidance for buildings where a waking watch would otherwise be needed.
Who decides whether our building needs a communal fire alarm?
The fire risk assessor, through the building's fire risk assessment. The Fire Safety Act 2021 confirmed the Fire Safety Order applies to the structure, external walls and flat entrance doors of multi-occupied residential buildings, and the responsible person must act on the assessment's findings. No managing agent, freeholder or contractor should add or remove communal detection without the fire risk assessment supporting it.
What does the Fire Safety (England) Regulations 2022 require for blocks of flats?
For buildings over 11 metres: quarterly checks of communal fire doors and annual checks of flat entrance doors. For buildings over 18 metres: monthly checks of firefighting lifts and key firefighting equipment, floor identification signage, secure information boxes, and building plans for the fire service. In all multi-occupied residential buildings, residents must be given fire safety instructions and information about fire doors.
Who maintains the AOV and smoke control system in a block of flats?
The responsible person — usually the freeholder or managing agent — must keep smoke control systems maintained as part of the general fire precautions. Best practice (and BS 7346 / EN 12101 guidance) is a weekly function check by the building manager and professional servicing at least twice a year. A stuck AOV is a common and serious fire risk assessment finding because escape routes then fill with smoke.
Do HMOs follow the same rules as blocks of flats?
No — HMOs (houses in multiple occupation) are treated differently because bedsits and shared houses rarely have compartmentation between units. LACORS guidance typically requires interlinked detection throughout an HMO — commonly a Grade D1 LD2 system in shared houses, or Grade A mixed systems in larger or higher-risk HMOs — so the whole house is alerted together. Licensing conditions from the local authority frequently specify the exact system.

Unsure What Your Block Actually Needs?

We work with managing agents, freeholders and RTM companies across Bedfordshire, Hertfordshire and London — fire risk assessments to PAS 79-2, detection and smoke control maintenance, conversions to BS 5839-6 Grade A systems, and BS 8629 evacuation alert installations. Straight answers first, quotes second.

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