Understanding Fire Alarm System Categories
🔥 Understanding BS 5839-1: Fire Alarm System Categories & Grades
At Kings Fire Ltd, we regularly help businesses across Bedfordshire, Hertfordshire, Buckinghamshire, the wider Home Counties and London stay compliant with UK fire safety standards. One of the most important standards is BS 5839-1, which sets out how fire alarm systems should be designed, installed, and maintained in non-domestic buildings.
Whether you manage an office, school, warehouse, or commercial premises, understanding the categories and grades of fire alarm systems is essential for compliance, safety, and insurance purposes.
📌 Categories of Fire Alarm Systems (BS 5839-1)
Fire alarm systems are divided into three main categories:
🖐️ Category M – Manual Systems
- The most basic type of fire alarm.
- Relies solely on manual call points (break-glass units).
- No automatic detection.
- Typically used in small, low-risk buildings where occupants can easily raise the alarm and evacuate.
👩👩👧👦 Category L – Life Protection Systems
These systems are designed to protect human life by giving early warning of fire.
- L1 – Maximum Protection
🔹 Detectors installed in all areas of the building.
🔹 Provides the earliest possible warning.
🔹 Often used in hotels, care homes, and large public buildings. - L2 – Additional Protection
🔹 Detectors in escape routes and high-risk areas (e.g. kitchens, boiler rooms).
🔹 Suitable for buildings with identified fire hazards. - L3 – Standard Life Protection
🔹 Detectors in escape routes and rooms opening onto escape routes.
🔹 Ensures occupants are alerted before fire blocks escape paths. - L4 – Escape Route Protection
🔹 Detectors only in escape routes and circulation areas.
🔹 Best suited for low-risk workplaces where staff know the layout well. - L5 – Custom Systems
🔹 Tailored solutions for specific fire risks.
🔹 Used when none of the standard categories (L1–L4) are suitable.
🏢 Category P – Property Protection Systems
These systems are designed to protect business assets and property.
- P1 – Maximum Property Protection
🔹 Detectors in all areas of the building.
🔹 Detects fire as early as possible, reducing the risk of major damage.
🔹 Often required by insurance companies. - P2 – Partial Property Protection
🔹 Detectors only in high-risk areas.
🔹 More cost-effective than P1.
🔹 Suitable for protecting valuable equipment or stock.
⚙️ Grades vs Categories: What's the Difference?
It's common to confuse grades and categories.
- Categories (M, L, P) → Refer to the coverage and purpose of the system (BS 5839-1, non-domestic buildings).
- Grades → Refer to the reliability and power supply of systems (BS 5839-6, domestic premises).
👉 For example:
- A Category L1 system may be installed in a hotel for maximum life protection.
- A Grade A system in a domestic setting would require mains power with battery backup.
✅ Why This Matters for Businesses in Bedfordshire, The Home Counties & London
Understanding BS 5839-1 ensures your business:
- Meets legal fire safety obligations.
- Remains compliant with insurance requirements.
- Provides the earliest possible warning to protect staff, visitors, and property.
At Kings Fire Ltd, we design, install, and maintain fire alarm systems across Bedfordshire, Hertfordshire, Buckinghamshire, the wider Home Counties and London . Our team will guide you through the right category of system for your building as the category for your fire alarm system is based on a detailed and professional fire risk assessment.
📞 Speak to the Experts
If you're unsure whether your current fire alarm system meets the requirements of BS 5839-1, our friendly team can help.
Contact us via our online enquiry form
Call our friendly fire safety team for expert advice on 01462 337037
Prefer an in-person consultation? We're happy to offer a free site visit to discuss your fire safety requirements