A practical guide to BS 5839-1:2025 and BS 5839-6:2019+A1:2020 fire alarm categories and requirements across residential and commercial premises.
The latest revision includes enhanced requirements for system design, installation, commissioning, and maintenance of fire detection and alarm systems.
Core compliance requirements that all systems must meet under the new standard.
The required fire alarm category depends on the building use, occupancy type, and whether occupants are sleeping. Below is guidance for common premises types — always confirm with a competent fire risk assessor.
Self-contained holiday lets and short-term rentals require adequate early warning systems.
Specific Requirements:
Commercial accommodation requires comprehensive automatic detection throughout.
Specific Requirements:
HMOs require comprehensive fire alarm coverage due to higher risk from multiple occupancies.
Specific Requirements:
Industrial premises require systems based on property protection and life safety needs.
Specific Requirements:
Commercial office spaces require life protection systems appropriate to occupancy and risk.
Specific Requirements:
Healthcare premises require enhanced protection due to vulnerable occupants and sleeping risks.
Specific Requirements:
Choosing the right detector type for each area is critical for reliable detection and minimising false alarms.
Detect visible smoke particles using a light beam. Best for slow-burning fires that produce large smoke particles.
Best for: Living rooms, hallways, bedrooms
Detect invisible smoke particles from fast-flaming fires using ionised air.
Best for: Areas where fast-flaming fires are likely
Respond to increases in temperature rather than smoke. Ideal for areas where smoke detectors may cause false alarms.
Best for: Kitchens, garages, boiler rooms
Combine optical smoke and heat detection technology for improved detection and reduced false alarms.
Best for: All areas, especially prone to false alarms
Detect the presence of carbon monoxide gas, a colourless and odourless toxic gas.
Best for: Near boilers, gas appliances, fireplaces
Detect flames using ultraviolet and infrared sensors. Provide rapid detection of hydrocarbon fires with minimal false alarms.
Best for: Industrial areas, aircraft hangars, fuel storage
Fire alarm systems in the UK are governed by two key British Standards depending on whether the premises are commercial or domestic.
Commercial & Non-Domestic Premises
This British Standard provides recommendations for the design, installation, commissioning and maintenance of fire detection and fire alarm systems in non-domestic premises. It covers automatic fire detection systems (Categories L1-L5) and manual fire alarm systems (Category M).
Domestic & Residential Premises
This standard covers fire detection and fire alarm systems for dwellings. It specifies different system grades (A, B, C, D, F) and categories of protection (LD1, LD2, LD3) to suit various domestic requirements, from basic battery-operated systems to sophisticated monitored installations.
Installed throughout all areas of the building for maximum life protection.
Best suited for: High-risk premises, sleeping accommodation
Detection in defined areas plus escape routes for early warning.
Best suited for: High-risk areas identified by risk assessment
Designed to give a warning of fire at an early enough stage to enable all occupants to escape.
Best suited for: Most common in commercial buildings
Installed within escape routes only.
Best suited for: Buildings where occupants are awake and familiar with premises
Designed to satisfy a specific fire safety objective other than life protection.
Best suited for: Property protection, heritage buildings
System installed throughout all areas of the building for property protection.
Best suited for: High-value property, critical infrastructure
Detection installed in specified areas only, for property protection.
Best suited for: High-value or high-risk areas, unmanned premises
Professional fire alarm system installed throughout the home.
Best suited for: New build properties, highest level of protection
Professional system with detectors in circulation spaces and high-risk rooms.
Best suited for: Recommended for rental properties
Professional system with detectors in circulation spaces only.
Best suited for: Minimum standard for rental properties
BS 5839-1:2025 categorises fire alarm systems by the level of protection they provide. Categories M, L and P define manual and automatic systems for life and property protection.
Fire alarm systems operated manually by people discovering fire.
Includes manual call points, sounders, and control panel. No automatic detection.
Automatic fire detection systems to protect life.
Subcategories:
Automatic systems primarily for property protection.
Subcategories:
Under The Regulatory Reform (Fire Safety) Order 2005, landlords must ensure adequate fire detection and warning systems are installed and maintained. Failure to comply can result in unlimited fines and imprisonment.
Need more guidance?
Browse our other fire safety resources or get in touch if you can't find what you're looking for.
We use essential cookies to run the site. Optional analytics and advertising cookies help us understand and improve visits — only used with your consent.