Trawling the internet with your fire risk assessment or insurers document in your hand? You know you need to find an approved designer and installer of fire alarm systems, but you also need to cut through the jargon so you understand what it is you’re getting.

Understanding the different categories of fire alarms and adhering to the latest fire safety laws and standards, such as BS5839-1: 2025, is essential for compliance and safety. It involved processing a lot of technical information with industry specific details. Your fire risk assessment, and documents from insurers may be full of terms such as L4 or addressable system or BS5839-1:2025.

Here’s a quick guide to some of the common terms you’ll find in those documents.

Fire Alarm Categories

Fire alarms typically fall into three main categories: manual, automatic, and addressable systems. Beyond these, fire alarm systems are further divided into categories based on the level of coverage they provide, commonly referred to as L1, L2, etc.

  1. Manual Systems: These require human intervention to activate. They include break-glass units and manual call points, commonly found in public spaces where staff can quickly alert others in case of a fire.
  2. Automatic Systems: These alarms detect smoke, heat, or flames automatically. They are ideal for areas where immediate detection is critical, such as manufacturing plants or hotels.
  3. Addressable Systems: These advanced systems allow precise identification of the fire’s location within a building. They’re particularly useful in large premises, enabling swift response and evacuation.

L category fire alarms are designed to protect Life. P category fire alarms are designed to protect Property. P1 protects the whole building, whereas P2 protects only defined parts of the building. It is designed to prevent the loss of property.

Category L fire alarm systems range from L1 to L5 as follows;

  • L1 Systems: Provide the highest level of coverage, with detectors in all areas of the building. They are suitable for high-risk environments where early detection is crucial. This provides for Automatic Fire Detection to be installed in all areas of a building.
  • L2 Systems: Offer coverage in defined areas of high risk or hazardous, such as boiler rooms, non fire resistant store rooms, sleeping risk etc. In addition automatic fire detection should be installed on escape routes as well as rooms opening onto escape routes.
  • L3 Systems: Focus on escape routes and areas that lead to exits, ensuring that these paths are clear in case of evacuation.
  • L4 Systems: Provide automatic fire detection on escape routes only
  • L5 Systems: These are more specialised, targeting specific risks unique to the building’s use and generally specified by the fire risk assessor.

UK Fire Alarm Law

In the UK, businesses must comply with the Regulatory Reform (Fire Safety) Order 2005, which mandates that all commercial spaces perform a fire risk assessment. This assessment determines the necessary fire alarm systems and other safety measures. Regular maintenance and testing of fire alarms are also legally required to ensure they remain functional.

BS5839-1: 2025

The British Standard BS5839-1: 2025 provides comprehensive guidelines on the design, installation, commissioning, and maintenance of fire detection and fire alarm systems in non-domestic premises. It emphasises the importance of choosing a system that suits the specific needs of the building and its occupants. Key updates in this standard include enhanced requirements for system testing and documentation, ensuring systems are always up-to-date and reliable.

Selecting the right fire alarm system involves understanding these categories, complying with current legislation, and following established standards. By doing so, you can ensure that your premises are safe and compliant, providing peace of mind for everyone involved.

Keybury Fire and Security are fire alarm experts, designing, installing, commissioning and maintaining fire alarm systems. We protect businesses across Yorkshire, Lancashire and the North of England. Keybury Fire and Security are BAFE Certified and NSI GOLD approved. Our team of designers and installers are FIA trained and highly skilled. Schedule your free fire alarm consultation today. Book online or contact us directly on 0800 458 7486 or sales@keybury.co.uk.