Why build quality matters
Fire alarm expectations in residential buildings are shaped by more than occupancy. Construction quality, compartmentation, fire doors, escape routes, common parts, and the reliability of passive protection all affect what is appropriate.
A purpose-built block with strong compartmentation is not the same risk as a poorly converted building with weak separation, even if both contain flats.
Purpose-built blocks and stay put
Many purpose-built blocks are designed around compartmentation and a stay put strategy. If each flat is a good fire-resisting compartment, a fire in one flat should not quickly affect the protected escape routes or other flats.
In that context, BS 5839-6 provision is often focused inside the individual flats, with the building relying heavily on passive protection in common parts.
Typical provision in well-compartmented flats
- Domestic detection within each flat, such as smoke alarms in circulation areas and heat detection in kitchens where appropriate
- No automatic common alarm in some purpose-built blocks where compartmentation and strategy support that approach
- Fire doors and construction quality doing much of the safety work
- Management arrangements to keep common parts clear and maintained
HMOs and conversions
HMOs and converted buildings often rely less confidently on compartmentation. Older layouts, mixed construction, shared escape routes, and unknown voids can make early detection and warning more important.
In those settings, simultaneous evacuation and more extensive detection may be needed, depending on the fire risk assessment and applicable guidance.
Common parts: BS 5839-1 or BS 5839-6
Staircases and common parts can create confusion. Domestic standards and non-domestic standards may both be relevant depending on the building, the system objective, and the management arrangements.
The answer should come from competent assessment and design rather than simply copying what was done in another building.
Post-Grenfell changes
The Fire Safety Act 2021 clarified that the Fire Safety Order applies to the structure, external walls, and flat entrance doors that open onto common parts in buildings containing two or more domestic premises.
Responsible persons should make sure fire risk assessments consider these areas where relevant and should not assume older assessments are still complete.
Linked measures that depend on build quality
- Compartmentation to keep fire and smoke out of escape routes
- Fire doors that close and seal properly
- Emergency lighting so escape routes remain usable
- Suitable detection and warning for the building strategy
- Competent management and record keeping
Key takeaway
Two residential buildings can need different alarm arrangements because the construction and management are different. Standards are there to be applied intelligently, with the fire risk assessment connecting the building condition to the right practical measures.