Free online tool
Fire Alarm Category Finder (BS 5839-1:2025)
Find out which fire alarm system category is usually used for your type of building under BS 5839-1:2025, what M, L1 to L5, P1 and P2 mean, and what to agree with your fire risk assessor.
About this tool
The SPS Technical Fire Alarm Category Finder is a free interactive guide for UK non-domestic premises. It uses the premises type and factors such as sleeping accommodation, insurer requirements, inner rooms, unoccupied areas and phased evacuation to show the BS 5839-1 fire alarm category usually seen in practice, based on Annex A of BS 5839-1:2025 as published by the Fire Industry Association. It explains each category, highlights relevant 2025 changes, and produces a PDF guide with sources. It is guide only: the category must be set by the fire risk assessor or a fire safety specialist.
Designed for Responsible Persons, facilities managers, estates teams, landlords, architects and business owners. SPS Technical provides commercial fire and security design, installation, maintenance and monitoring across Yorkshire, Lincolnshire and the Humber.
Start Fire Alarm Category Finder
Choose your type of premises and tick any factors that apply. You'll see the category usually used in practice, what it means, the 2025 changes to be aware of, and a PDF guide with sources. This is a guide only: your fire risk assessment sets the category.
This tool is a guide only. It shows the category of fire alarm system usually found in practice for the type of premises selected, based on the informative Annex A of BS 5839-1:2025 as published by the Fire Industry Association, and on GOV.UK fire safety guidance. It is not a design, specification or fire risk assessment, and it is not SPS Technical's advice for your building. The category must be set by your fire risk assessor or another fire safety specialist.
This tool provides an initial indication only. Results are based on the information you have provided and recognised industry standards. They are not a substitute for a site-specific technical assessment, insurer advice or formal compliance review. Maintenance requirements may vary depending on system type, site conditions, monitoring arrangements, certification status and insurer requirements. SPS Technical can confirm the correct requirements following a review of your system.
Fire Alarm Categories Explained
BS 5839-1 is the British Standard code of practice for fire detection and fire alarm systems in non-domestic premises. It groups systems into categories by what they are designed to protect: people (Category L), property (Category P), or manual alarm only (Category M).
Category M (Manual): Manual call points and sounders only, with no automatic fire detectors. People who discover a fire raise the alarm.
Category L1 (Life, whole building): Automatic detection throughout all areas of the building, to give the earliest possible warning to occupants.
Category L2 (Life, defined areas): Everything in L3, plus detection in defined areas where a fire is more likely to start or the risk to people is high. From 2025, rooms where people sleep count as high-risk rooms.
Category L3 (Life, escape routes and rooms off them): Detection on escape routes and in most rooms opening onto them, to warn people early enough to escape before routes become impassable.
Category L4 (Life, escape routes): Detection on escape routes only, such as corridors and stairways.
Category L5 (Life, specific objective): Detection designed to meet a specific fire safety objective set by the fire risk assessment, such as protecting an inner room or releasing door hold-open devices.
Category P1 (Property, whole building): Automatic detection throughout the building to protect property and business continuity, often required by insurers.
Category P2 (Property, defined areas): Automatic detection in defined high-risk or high-value areas to protect property.
Categories are often combined, for example M/P2 (manual call points plus property detection in defined areas) or M/L5 (manual call points plus detection for a specific objective).
Who Decides the Category?
The category is not chosen by the fire alarm designer or installer. According to the Fire Industry Association's guidance on BS 5839-1, it is set by a fire safety specialist, such as a fire risk assessor, fire engineer or the enforcing authority, usually as part of the fire risk assessment required by the Regulatory Reform (Fire Safety) Order 2005.
The agreed category should be written into the specification. For L2, L3, L5 and P2 systems, the specification should also say which areas are protected and what types of detector are used.
Typical Categories by Type of Premises
Annex A of BS 5839-1:2025 gives the categories usually found in practice for common types of premises. It is informative, meaning it reflects custom and practice rather than a requirement. In summary:
- Office, shop, factory, warehouse or restaurant (no one sleeps there): M, M/P2 or M/P1
- Hotel, hostel, student accommodation or HMO: L1 or L2 (in practice, usually L1)
- Residential care home: L1
- Hospital or other healthcare with overnight patients: L1 (with variations agreed for the building)
- Healthcare without sleeping (surgery, clinic, health centre): L2 or L3
- School or college (not a small single-storey school): M, M/P2, M/P2/L4 or M/P2/L5
- Pub or bar without sleeping accommodation: M or M/P2
- Pub or bar with sleeping accommodation (rooms or a flat): L2
- Place of assembly for fewer than 300 people (hall, church, small venue): M
- Place of assembly for 300 people or more (theatre, cinema, large venue): L1 to L4, set by the fire risk assessment
- Covered shopping centre: L1 to L3, decided case by case
- Transport terminal (station, airport, bus or ferry terminal): M/L5
What Changed in BS 5839-1:2025
The 2025 edition treats rooms where people sleep as high-risk rooms, so they are covered in Category L2, and heat detectors should no longer be used in sleeping rooms in new work. This change is not retrospective, so existing systems don't need altering unless they are undergoing new works.
Stairway lobbies can no longer be left without detection as low-risk areas. Residential care homes without an Alarm Receiving Centre connection, and premises with more than one zone per storey but no zone plan, are no longer acceptable variations. The FIA's guide to the changes covers these in detail.
SPS Technical designs, installs and maintains fire alarm systems to BS 5839-1 as a BAFE SP203-1 registered company. See our fire alarm services and fire alarm maintenance.
Fire Alarm Category Finder FAQs
What fire alarm category does an office need?
Offices, shops and other workplaces where nobody sleeps usually have a Category M system, which is generally enough for fire safety legislation. Automatic detection (P1 or P2) is often added for insurers. Your fire risk assessment decides.
What is the difference between L1 and L2?
L1 provides automatic detection throughout the whole building. L2 covers escape routes, rooms opening onto them, and defined higher-risk areas, which from 2025 include rooms where people sleep.
What does M/P2 mean?
Manual call points throughout the building (Category M), plus automatic detection in defined areas to protect property (Category P2), such as stores, plant rooms or server rooms.
Who is responsible for choosing the category?
A fire safety specialist, such as your fire risk assessor, fire engineer or the enforcing authority. The designer and installer then design the system to that category.
Is this tool SPS Technical's advice for my building?
No. It is a guide based on published sources: BS 5839-1:2025 Annex A as summarised by the FIA, and GOV.UK fire safety guidance. It cannot replace a fire risk assessment or a system design.
Want a Professional to Verify Your Findings?
Complete the tool above, then request a professional review from SPS Technical. We can confirm the findings on site and explain any remedial options.