Most commercial fire alarm systems in the UK are one of three types: conventional, addressable or wireless. All three can meet BS 5839-1 when they are designed properly. The right choice depends on the size of the building, how it is used and how quickly you need to find a fire.
Conventional systems
A conventional system groups detectors and call points into zones, each wired back to the panel on its own circuit. When a device operates, the panel shows which zone is in alarm, but not which device.
- Good for: small buildings with a handful of zones, such as shops, small offices and small HMOs with a panel.
- Strengths: lower equipment cost and simple to understand.
- Weaknesses: in a large zone, staff and firefighters have to search for the device that operated, and tracing false alarms takes longer.
Addressable systems
An addressable system connects every device on a loop, and each device has its own address. The panel shows exactly which detector or call point has operated, often with a text description such as "Flat 12 lobby smoke detector".
- Good for: larger or multi-storey buildings, blocks of flats with communal systems, care homes, hotels and anywhere with complex cause and effect.
- Strengths: pinpoints the device, makes false alarms easier to trace, supports more sophisticated cause and effect, and usually needs less cable because devices share a loop.
- Weaknesses: higher equipment cost and needs programming by a competent engineer.
As a rough guide, buildings that would need more than eight zones on a conventional system usually suit addressable better.
Wireless (radio) systems
Wireless systems use battery-powered devices that communicate with the panel by radio, certified to BS EN 54-25. Many are addressable.
- Good for: listed buildings, occupied homes and HMOs, temporary buildings and anywhere cabling would cause damage or disruption.
- Strengths: fast installation with little making good.
- Weaknesses: higher device cost, and batteries need replacing on a schedule.
Hybrid systems
Many sites combine a wired addressable loop with radio devices where cabling is difficult. This is often the most practical answer in refurbishments.
How to decide
- How many zones would a conventional system need?
- Do people sleep in the building?
- How important is pinpointing the device for evacuation and false alarm management?
- Is the building listed or occupied during the works?
Your fire risk assessment and a site survey should settle it. Our guide to fire alarm categories explains how coverage is decided.
This guide is general information about UK fire safety law and standards, not legal advice for a specific building. If you are unsure what applies to yours, ask us or a qualified adviser.