Fire Alarm Installation in North London: Commercial Units and Communal Areas

Commercial units: what a BS 5839-1 system involves

Design first, then install, then commission, then maintain. Each step has paperwork.

BS 5839-1:2017 is the code of practice for fire detection and alarm systems in non-domestic buildings. It sets out how to choose a category, place detectors and sounders, and keep the system working. The category is a decision for the responsible person, informed by the fire risk assessment. L categories protect life, P categories protect property, and M is manual call points only. Our categories guide explains them.

1. 1Survey and design. We walk the building, mark the zones and the cause-and-effect, and agree the category with you.
2. 2Install. Addressable or conventional, wired or wireless, depending on the building. Wireless suits occupied units and listed fabric where cable routes are hard.
3. 3Commission. Every device tested, and a certificate issued with the zone plan.
4. 4Maintain. Regular servicing, a logbook and a named contact. Article 17 of the Fire Safety Order makes maintenance the responsible person's duty.

Typical commercial settings in this area: shops and takeaways on high streets, offices over retail, trade counters and warehouses in industrial estates, and restaurants where kitchens create nuisance alarms. See alarms for restaurants and kitchens, alarms for warehouses and alarms for small offices.

Blocks of flats: BS 5839-1, stay put and when a common alarm applies

This is the most misunderstood part. The alarm has to match the evacuation strategy.

Most purpose-built blocks are designed on a stay-put basis. If there is a fire in one flat, that flat evacuates and the others stay where they are unless told otherwise. This works because the walls, floors and flat entrance doors hold the fire back. A single alarm that sounds in every flat undermines it, so these blocks typically have detection and an alarm only where the fire strategy calls for it.

Other buildings need everyone out at once. Converted houses and older blocks with weak compartmentation, no protected stair or poor fire doors often rely on early warning of residents. In those, a communal system to BS 5839-1 covering the shared stairs, hallways and lobbies may be needed. Whether you need it is a fire strategy and fire risk assessment question, not a choice we can make for you from the outside. Our guide on whether flats need fire alarms in communal areas covers it, and buying a fire alarm for a block covers what to ask for.

Alarms inside individual flats are outside this page. We install and service communal and commercial systems.

Evacuation alert systems for blocks that must switch strategy

A different system with a different job.

When a building with a stay-put strategy is found to have serious defects, such as combustible cladding or failed compartmentation, the strategy can change to simultaneous evacuation. An evacuation alert system gives the fire and rescue service a way to tell residents to leave, under the code of practice BS 8629. It is not a fire alarm and it does not replace one. See BS 8629 evacuation alert systems. The wider rules for tall blocks are in the Building Safety Act explained guide.

What else fails an inspection on alarm systems

Three jobs that sit next to the alarm.

• Emergency lighting to BS 5266-1, tested and logged. See the emergency lighting guide.
• Fire doors that do not close, so smoke spreads regardless of the alarm. See fire door inspections in North London.
• Servicing gaps. A system with no service record is a finding in any fire risk assessment. See how often fire alarms need servicing.

Price and how we quote

A service visit starts from about £400 + VAT for a small system.

An installation price depends on the category, the number of devices, the cable routes and whether the building is occupied during works. We cannot give a sensible figure without a survey or good photos and a plan. We then give one fixed price including travel. London parking and congestion are in it already. For comparison tips, see how to compare fire alarm quotes. The national service page is fire alarms and the hub is North London.

Sources

• Regulatory Reform (Fire Safety) Order 2005 (legislation.gov.uk)
• London Fire Brigade: fire safety in the workplace

Updated October 2026 by Sebastian Grabowski, DC Fire & Security, 2 Winsdon Court, Luton LU1 5LZ.