Buyer guide
Required if…Do I need a fire alarm system?
The law requires a way of warning everyone in the building. For a small simple premises that can be a shout or a hand bell. For most others it is a system to BS 5839-1. What category you need and how servicing works. What the weekly test is and why the service contract is where small businesses get locked in.
Applies to: England and Wales under the Fire Safety Order. The same duty exists in Scotland and Northern Ireland under their own fire law. BS 5839-1:2025 is the standard everywhere in the UK.
Looking for the technical detail? Read the version for professionals → BS 5839-1:2025 categories and design. Commissioning and servicing schedules. False alarm management.
Do I need one? You need a way of warning everyone in the building that there is a fire. What that means for your premises comes out of your fire risk assessment. For a small single room shop it can be a shout. For most businesses it means an installed system.
Who decides what system? Your fire risk assessment. Not the alarm company. That order matters because the alarm company has an obvious interest in the answer.
Where does it go wrong for buyers? Not usually on the install. On the service contract. Twice yearly visits sold on three and five year terms with auto renewal. And a weekly test you are paying someone to do that takes you five minutes.
What the law actually requires
Article 13 of the Regulatory Reform (Fire Safety) Order 2005 says the responsible person must ensure the premises are equipped with appropriate fire detectors and alarms to the extent appropriate. Article 17 says any fire safety equipment must be kept in efficient working order and in good repair.
"To the extent appropriate" is the whole game. The fire risk assessment decides what is appropriate. The Order does not specify a category or a standard or a servicing interval. Scotland and Northern Ireland impose the same duty under their own legislation.
This is the code of practice for fire detection and alarm systems in non domestic premises. It is not law. It is what fire officers and insurers and courts treat as the benchmark for "appropriate" and "maintained". It sets the system categories and the design rules. It sets the servicing regime. A weekly user test. A six monthly inspection and service. All devices tested across the year. The 2025 edition replaced BS 5839-1:2017. An existing system does not have to be upgraded because the edition changed.
Insurers frequently require a system to BS 5839-1 of a particular category, serviced by a third party certified company. BAFE SP203-1 is the usual scheme. They will ask for the service records after a fire. Check the policy wording. "Serviced by a competent person twice a year" is common. "On a maintenance contract" is rarer than the sales pitch suggests.
What this means for your premises
The category is the decision that drives everything else and it is your assessor's decision.
Small and simple with one occupier and no sleeping. A small shop or a café or a ground floor office. Often Category M with manual call points and no automatic detection. Sometimes a very simple L4. Some are small enough that the assessment concludes a shouted warning is adequate. Domestic smoke alarms sometimes get accepted here. They are not a BS 5839-1 system and an insurer may say so.
Ordinary commercial premises with more rooms and people: L4 (detection on escape routes) or L3 (escape routes plus the rooms opening onto them). This is most offices, shops and restaurants.
Sleeping risk. Hotels and B&Bs. HMOs and care homes. Flats above. L2 or L1 with detection in bedrooms and high risk rooms. No shortcuts here.
Property protection (P categories): only where you or your insurer want the building protected when it is empty. Usually in addition to a life safety category.
Your options
Installation
Get the category from the fire risk assessment first. Then get two or three quotes to that specification from BAFE SP203-1 registered companies. Make sure each quote says which category it is designing to. A quote that does not name the category is not a quote for your building.
A conventional system is zoned and cheaper and fine for small premises. An addressable system identifies each device at the panel and suits larger or complex buildings. For a small premises conventional is usually the right answer whatever the salesperson prefers.
Servicing: the two layers
Layer 1: the weekly test by you. Operate a different manual call point each week. Confirm the sounders and the panel respond. Reset. Write it in the log book. Five minutes. Free. The standard requires it and it is the single most common gap fire officers find. Do not pay anyone to do this.
Layer 2: six monthly inspection and service by a competent engineer. Two visits a year. The engineer tests all devices across the year and checks the panel and the batteries. It all goes in the log book. Use a BAFE SP203-1 company or an equivalent third party certified one. Pay per visit or on a one year agreement with a 30 day notice clause. That is the whole requirement.
Monitoring
Connection to an alarm receiving centre is an option and not a requirement for most premises. Sleeping risk premises and some insurers want it. Everyone else should decide on the merits and not because it came in the package.
What it should cost
A small conventional system installed: £900 for the simplest premises and £2,520 for an office or shop with 5 to 19 people. A medium addressable commercial system: £5,000. Large or complex sites: £10,000 upwards.
Six monthly servicing for a small system: £150 a year for the simplest premises and £350 for 5 to 19 people. It is priced by the number of devices. Extra visits for false alarms or faults are usually charged per call out. Get the rate in writing.
Figures are typical prices taken from published commercial price guides and checked October 2026. Same method on every page. Larger or more complex premises sit above them.
What you shouldn’t be sold
- A higher category than your assessment requires. L1 everywhere is not "safer" for a small shop. It is more detectors to buy and service. The assessment sets the category.
- The weekly test as a paid service. It is yours to do and it takes five minutes. It goes in the log book either way.
- A three or five year service contract with auto renewal. The requirement is two visits a year by a competent person. Nothing about that needs a term. Read the notice clause before you sign anything.
- A new panel because of BS 5839-1:2025. The new edition does not make an existing system non compliant.
- An addressable system for a two room premises. Conventional is cheaper to buy and to service. It is adequate for small buildings.
- Monitoring "included" in the package. It is a separate service with a separate monthly cost. Decide whether you need it.
- Assessment and installation from the same company on the same day. The assessment sets the category and the installer builds to it. When one company does both the category tends to grow.
Check what else your business needs
The alarm is one part of your fire precautions. The same assessment covers emergency lighting and extinguishers. Run the Compliance Check to see everything your premises needs.
Quick answers
- Is a fire alarm a legal requirement for a business?
- The law requires appropriate means of detecting fire and warning people. Your fire risk assessment decides what that is. For a small single room shop with a clear exit a shouted warning or a manual bell can be enough. For anything larger or with more people or sleeping risk it means an installed system to BS 5839-1.
- What are the fire alarm categories, and which do I need?
- Category M is manual call points only. L1 to L5 are life protection systems with automatic detection. L1 is everywhere and L5 is targeted at a specific risk. P1 and P2 protect property. Most small commercial premises need M or L4 (escape routes) or L3 (escape routes plus rooms opening onto them). Sleeping risk usually needs L2 or L1. Your fire risk assessment sets the category. The alarm company installs to it.
- How often does a fire alarm need servicing?
- BS 5839-1 recommends inspection and servicing at intervals not exceeding six months. So twice a year, with every device tested over the course of a year. Plus a weekly test of one call point by you, recorded in the log book.
- Can I do the weekly fire alarm test myself?
- Yes, and you should. Operate a different manual call point each week. Check the alarm sounds and the panel responds. Reset it and record it in the log book. It takes five minutes and needs no contractor.
- How much does a fire alarm system cost?
- A small conventional system is £900 installed for the simplest premises and £2,520 for 5 to 19 people. A medium commercial addressable system is £5,000. Large or complex sites run from £10,000. Six monthly servicing is £150 a year for the simplest premises and £350 for 5 to 19 people.
- Do I need a fire alarm service contract?
- You need the system serviced twice a year by a competent person. You do not need a multi year contract to achieve that. Pay per visit or take a one year agreement with a 30 day notice clause. Anything longer is a lock in you have no reason to accept.
- Are smoke alarms enough for a business?
- Domestic grade smoke alarms are for homes and are not a BS 5839-1 system. They can be adequate for very small simple premises where the fire risk assessment says so. They are not what an insurer or a fire officer means by a fire alarm system.
- What is BS 5839-1:2025?
- The current British Standard for fire detection and alarm systems in non domestic premises. It was published in 2025 and replaced the 2017 edition. It is a code of practice and not law, but it is what the Fire Safety Order treats as the benchmark. An existing system installed to the 2017 edition does not have to be replaced.
Find and check
Who can I use for this?
We do not recommend suppliers. Here is the official register and what to check before you book.
The register
- BAFE SP203-1 registered companies Third party certified for fire detection and alarm systems.
- FIA members Fire Industry Association member companies.
Check
- BAFE SP203-1 certification for the company.
- That they will design to the category your fire risk assessment set and not a higher one.
- A log book they will complete at every visit.
Ask
- What category does my assessment call for and are you quoting to that?
- What is the price per six monthly visit and what is the call out rate for a fault?
- Can I pay per visit or on a one year agreement with thirty days notice?
Insist on
- Two visits a year with every device tested across the year. That is the standard.
- The weekly test stays with you. It is not on the invoice.
- No term longer than a year and no automatic renewal.
General information about UK compliance, written for the person paying the bill. Not legal advice. If your situation is unusual, get a professional to look at it. See our editorial standards.