Fire Detection in Residential Blocks and Common Parts
Blocks of flats are one of the most scrutinised areas of fire safety, and detection in them is more nuanced than in a single occupied building. A flat is usually its own fire-resisting compartment, the traditional strategy is often stay-put, and different parts of the building fall under different standards. Getting the arrangement right — and knowing which code applies where — matters enormously. This guide covers detection in residential blocks and their common parts.
The recurring theme is that the detection has to work with the building's compartmentation and fire strategy, not against it.
Who this is for
This is for competent fire alarm and security engineers working on blocks of flats. The experience level assumed is competent engineer. Use it for the principles; the specific design and strategy come from the fire risk assessment, BS 5839-1 and BS 5839-6, the relevant Building Regulations guidance, and the building's fire strategy.
Detection in blocks of flats
Many purpose-built blocks have traditionally relied on a stay-put strategy: each flat is built as a fire-resisting compartment, so that a fire in one flat can be contained while residents elsewhere stay put. In that model, detection within each flat is typically a domestic-type system that warns that flat's occupants, while common parts may have a separate arrangement. The overall approach depends on the building's construction and fire strategy — and, as with much residential fire safety, it has been under active review following major incidents.
BS 5839-1 vs BS 5839-6
A key distinction for engineers is which code applies. BS 5839-1 is the code of practice for fire detection and alarm systems in non-domestic buildings; BS 5839-6 covers systems in domestic premises, including dwellings and individual flats. In a block, detection within the flats typically follows BS 5839-6, while communal or non-domestic areas such as commercial units or certain common parts may follow BS 5839-1. Knowing which standard applies to which part of the building is essential to designing and maintaining the system correctly.
Common-parts detection
Whether and how the common parts — corridors, stairs, plant rooms — are protected depends on the building's fire strategy and construction. This needs care: in a stay-put building, adding unnecessary or poorly considered common-area detection that raises a communal alarm can trigger evacuations that conflict with the strategy the building was designed around. The right arrangement follows the fire risk assessment and the relevant standards for the specific building, balancing protection against the intended evacuation approach.
Evolving guidance
Fire safety in residential blocks has been under significant review, with greater scrutiny of stay-put strategies, compartmentation, and the means to change to evacuation where needed — including evacuation alert systems in some higher-rise buildings. The practical point for engineers is that guidance and expectations in this area have moved, and continue to, so the design for a specific building must follow current guidance and the building's own fire strategy rather than long-standing assumptions.
Common points to check
Recurring issues include confusion over which standard applies to which part of a block, common-area detection that conflicts with a stay-put strategy, and systems designed to superseded assumptions. Confirming the arrangement against the current fire strategy and the correct standard for each area is central to this work.
When not to rely on this alone
When not to use this article: do not use it to design detection or set the strategy for a specific block. Those come from the fire risk assessment, BS 5839-1 and BS 5839-6, the relevant Building Regulations guidance, and the building's fire strategy, applied by competent professionals.
Relevant standards
Detection in flats follows BS 5839-6, and in non-domestic parts BS 5839-1 — both codes of practice — within the building's fire strategy and Building Regulations statutory guidance. The legal duty for fire precautions in the relevant parts sits under the Regulatory Reform (Fire Safety) Order 2005 and related residential fire-safety legislation. Separate the legal duty from the recommended methods when advising a client, and always work to current editions.
Professional disclaimer
This is an educational and workflow resource for competent engineers and does not replace the current British Standards, the fire strategy, the relevant guidance, or competent judgement. Verify residential block detection against current documentation.
Related documentation
Use this with the current BS 5839-1 and BS 5839-6, the building's fire strategy and risk assessment, and the relevant residential fire-safety guidance. Record clearly which standard applies to each part of the building.