A wireless fire alarm system uses radio links instead of cables to connect battery-powered detectors, call points and sounders to the control panel. It makes most sense where cabling would be difficult, disruptive or damaging, such as listed and heritage buildings, occupied premises, temporary sites and extensions. Designed to BS 5839-1 with components that conform to BS EN 54-25, a wireless system can give the same protection as a wired one. It costs more per device, and you will need to plan for battery replacement.
How a wireless fire alarm system works
Each wireless device contains a radio and its own batteries. It communicates with a control panel, or with a radio hub or translator connected to a panel. The system constantly checks the radio links. If a device stops responding, suffers interference or runs low on battery, the panel reports a fault. A radio-linked fire alarm system has three main parts:
- Control and indicating equipment: either a dedicated wireless panel or a wired addressable panel with a radio interface
- Radio hubs, translators or expanders: these link wireless devices to the panel and extend coverage
- Field devices: smoke, heat and multi-sensor detectors, manual call points, sounders, visual alarm devices (VADs), input/output units and door controls
EN 54-25 explained
BS EN 54-25 is the part of the EN 54 series that covers fire alarm components using radio links. It sets requirements, test methods and performance criteria for radio-linked components. Where a system uses both wired and radio links, the relevant parts of EN 54 apply together with Part 25. Key points include:
- Battery life: a component powered by its own battery must be able to operate normally for at least 36 months. The manufacturer must back this up with a calculation that allows for battery self-discharge.
- Low-power warning: components are tested to make sure they signal a fault when their power source runs low.
- Monitored communication: if a radio component can no longer reach the panel, the loss must be recognised in under 300 seconds and indicated in under 100 seconds. Removing a device from its base must also show as a fault.
- Interference: other users of the same radio band must not cause false alarms or fault warnings.
The Fire Industry Association (FIA) explains that BS 5839-1 requires radio components to comply with EN 54-25 and adds recommendations for the system as a whole. In particular, BS 5839-1 recommends a dual power supply for each component. A component powered by primary batteries should have two, so one keeps it working if the other fails. EN 54-25 itself allows a single primary battery, provided it fails in a predictable way, so check how each device is powered with your system designer.
Fully wireless vs hybrid systems
| Fully wireless | Hybrid (wired + wireless) | |
|---|---|---|
| Panel | Dedicated wireless panel | Wired addressable panel with a radio hub or loop interface |
| Best for | Buildings where almost no cabling is acceptable | Extending or filling gaps in an existing wired system |
| Example ranges | EMS SmartCell, or EMS FireCell with a Syncro AS panel and radio hub | EMS FireCell radio hubs on an addressable loop, and the EMS FireCell Fusion range with its Fusion Radio Loop Module |
| Main check | Radio coverage across the whole building | Compatibility with the existing panel's protocol |
Our wireless fire detection range also includes hybrid options from other manufacturers. Examples are Apollo XPander and REACH devices for Apollo loops, and Hochiki Ekho devices with the Ekho translator module.
When a wireless fire alarm makes sense
Listed and heritage buildings
Running fire-resistant cable through historic fabric, decorative ceilings and panelled walls can cause lasting damage and may need consent. Wireless devices keep that disruption to a minimum.
Occupied premises
Schools, hotels, offices, care settings and shops often cannot close for cabling work. Wireless devices can go in room by room with little dust, noise or downtime.
Temporary sites and phased works
On construction and refurbishment projects, the layout keeps changing. Wireless devices can be moved and re-used as the work progresses, subject to the fire strategy for the site.
Extensions and outbuildings
A radio hub can add detection to a new extension or nearby building without running cable back to the main panel, provided the panel is compatible and a radio survey confirms the link.
Pros and cons
Advantages
- Faster installation with far less disruption and making good
- Protects building fabric in listed and heritage properties
- Devices can be relocated as room layouts change
- Continuous monitoring of every radio link and battery
Disadvantages
- Devices cost more than their wired equivalents
- Batteries need scheduled replacement, which adds to the maintenance workload
- Thick walls, concrete floors and metalwork can limit radio range, so a survey is essential
- Each additional device must be checked for radio coverage
Radio surveys and design
Before installation, carry out a radio survey to prove every device position and signal path. Survey kits such as the EMS FireCell wireless survey kit let the designer test signal strength before any device is fixed. Where a hub sits in a plant room or metal enclosure, a remote aerial on suitable cable may be needed. The system must be designed, installed and commissioned by a competent person to the recommendations of BS 5839-1. Our guide to BS 5839-1 fire alarm categories explains how the level of protection is chosen.
Battery maintenance
Batteries are the main extra maintenance item for a wireless fire alarm, so plan for them from the start:
- Check the manufacturer's stated battery life for each device type. Life varies with device type, settings and how often the device is activated.
- Deal with low-battery faults promptly, and keep a stock of the correct spares, such as the EMS SmartCell 3.6V AA lithium battery. Only use the battery type specified in the device manual.
- Budget for battery changes across the whole system, since devices installed together tend to reach end of life together.
- Include wireless devices in routine testing and servicing, and record battery changes in the fire alarm log book.
Browse wireless fire detection or the full EMS range. All products supplied by JEM Systems UK are genuine, brand new and factory sealed, with fast, tracked UK delivery.
FAQs
Are wireless fire alarm systems allowed in commercial buildings?
Yes. BS 5839-1 covers radio-linked systems, and radio components should conform to BS EN 54-25. A competent person should design, install and commission the system.
How long do wireless fire alarm batteries last?
EN 54-25 requires battery-powered components to operate normally for at least 36 months. Actual life depends on the device and how it is used, so check the manufacturer's datasheet.
Can I add wireless devices to my existing wired fire alarm?
Often, yes, provided a hybrid interface exists for your panel's protocol, such as an EMS FireCell radio hub on an addressable loop or Apollo XPander on an Apollo loop. Confirm compatibility and carry out a radio survey first.
Is a wireless fire alarm as reliable as a wired one?
An EN 54-25 system continuously monitors its radio links and batteries and reports faults. If it is properly surveyed, installed and maintained, it can give the same level of protection as a wired system.
Do I need a radio survey?
Yes. Building construction affects radio range, and a survey proves each device position before installation.
This guide is general information; follow your fire risk assessment and a competent person's advice.