A wireless fire alarm system is not a cheap alternative to a wired system — in buildings where the cost of running cable is very high, it is a different way of doing the same job. When used in the right place, it reduces a renovation that would take weeks to just days; when used in the wrong place, it results in a system that is both expensive and burdensome to maintain.
Where wireless solutions are truly the right choice
What wireless detection saves is not the cost of cable, but the cost incurred in pulling the cable. There are five situations where this cost is high:
- Historic and listed buildings. Cutting channels in walls, drilling ceilings, or adhesive-mounting cable trays is often not a permitted intervention. Wireless devices are mounted with minimal contact to surfaces; in some applications visibility is also reduced by using an existing case or niche.
- Active and occupied buildings. In hotels, hospitals, shopping centers, dormitories and office buildings, renovation means closed rooms and floors. In wireless installation, the time spent per device is measured in minutes; operations remain largely open.
- Temporary and construction site use. If detection is needed during construction on a building site, a wired system represents both investment loss and decommissioning loss. A wireless set is installed, collected when the job is finished, and reused at another site.
- Spaces subsequently divided or repurposed. In locations where office floors are reorganized with partition walls, the wired loop is re-run each time; the wireless device is moved and re-registered to the panel.
- Spaces where it is not possible to safely route cable. Building elements containing asbestos, inaccessible ceiling voids, and walls where drilling new cable passages would compromise fire compartments.
Apart from these — in newly built, under-construction, or open-ceiling buildings — wired loop is almost always the better choice: no battery logistics, low cost per device, and simple maintenance.
EN 54-25: being wireless is not an exemption
Components of fire alarm systems are assessed under the EN 54 series. There is a separate section for components communicating via radio link: wheeled devices must have. A wireless smoke detector is assessed both according to its own device type section (such as EN 54-7 for smoke detectors) and according to EN 54-25 because of the radio link.
The basic expectations introduced by this section take wireless systems beyond being "simple radio communication":
- Communication interruption must be reported as a fault. When connection to a device is lost, the panel must indicate this as a fault within a specified time; a silently lost device is not acceptable.
- Battery depletion must be reported in advance. The device is designed to transmit a fault signal before the battery is fully depleted and to continue operating for a period after this signal. Thus battery replacement becomes a planned maintenance item.
- Resistance to signal degradation is required. The system must not lose its function due to a single frequency or single path becoming impaired.
The document to consult when selecting a product is not the manufacturer's promotional brochure but performance statement. If EN 54-25 does not appear in the scope, that product can only be evaluated as an auxiliary device, not as a component of a fire alarm system. For the standards aspect, see our EN 54 page .
Hybrid installation: the most frequently used form in practice
Entirely wireless systems are a minority in practice. The common form is hybrid configuration: the panel and main loop remain wired, and a wireless extender (translator) powered from the loop is placed in sections where cable cannot be run, and devices in that area communicate with this extender.
Hybrid configuration has three practical advantages:
- Battery load is limited. Only devices that truly need to be wireless run on batteries; maintenance burden is not distributed across the entire building.
- Existing systems are preserved. In a building with an existing wired system, the entire system is not replaced for an additional area.
- Addressing is centralized to one panel. Wireless devices also appear addressed on the panel; no burden of managing two separate systems on the operations side.
The important point here is that the location of the extender must be reachable by the wired loop and simultaneously at the center of radio coverage . These two conditions do not meet at the same location in most buildings; extender placement must be chosen by measurement, not for convenience.
Coverage and site survey
The most expensive mistake in a wireless project is estimating device count by looking at floor plans. Radio signal attenuates very differently depending on building materials:
| Obstacle | Effect | Field significance |
|---|---|---|
| Drywall partition, wooden door | Low | Generally causes no problems |
| Reinforced concrete wall, floor slab | High | Repeaters may be needed for inter-floor coverage |
| Metal cladding, sheet panels, suspended ceiling structure | Very high | Reflects signal; creates dead zones |
| Fire door, steel safe | High | Coverage changes completely when door is closed |
| Elevator shaft, wet area shaft | Very high | Usually requires a separate coverage island |
| High shelving, metal stock | Variable | In a warehouse, coverage changes as shelves fill — measurements taken in an empty warehouse are misleading |
For this reason the correct procedure is: first, on-site signal level measurement is performed with actual devices, dead zones are marked, the required number of repeaters is determined, and the proposal is based on this number. Wireless proposals given without measurement almost always grow during installation.
What is sought in measurement is not "is there signal" but safety margin. A connection operating at the limit will drop once furniture is placed, the warehouse is stocked, or a fire door is closed. An acceptable installation is one where each device can reach the panel through multiple independent paths .
Battery: the system's true operational item
The most obvious difference of wireless systems from wired systems is that devices carry their own power. This has three implications for operations:
- Battery life is not a fixed number. It varies depending on how frequently the device communicates, signal strength, temperature, and whether it serves a repeater function. Batteries of devices also serving as repeaters are noticeably depleted faster.
- Replacement must be planned. In a building with hundreds of devices, waiting for batteries to deplete individually means continuous service calls. In practice batteries are changed in groups according to device groups and this is written into the contract as a maintenance item.
- The correct battery type is critical. Devices typically use long-shelf-life lithium batteries; equivalent batteries purchased from stores both shorten life and impair the device's stated performance.
Battery management is a distinguishing part of wireless system periodic maintenance; is part of detection system maintenance it is planned within the scope.
Frequent objections and reality
| Objection | Reality |
|---|---|
| "Wireless is cheaper" | Cost per device is higher than wired equivalent. What becomes cheaper is labor, remedial work, and operational downtime; if these items are small, total cost on wireless comes out higher. |
| "Wi-Fi interferes" | Fire systems do not use Wi-Fi bands; they operate on bands reserved for short-range devices. Nonetheless, heavy radio traffic on the same band is accounted for in measurement. |
| "If signal is cut we won't know" | On the contrary, communication interruption is reported as a fault per EN 54-25. A broken wire in a wired circuit also generates a fault; there is no difference. |
| "Can be installed anywhere" | It cannot. Metal-intensive industrial spaces, large-span warehouses, and multi-story reinforced concrete buildings rapidly increase repeater count; beyond a certain point wired solution is both cheaper and more reliable. |
| "Battery life is ten years" | Catalog value is for a specific communication frequency and ambient temperature. On devices serving as repeaters and stationed in weak signal areas, the period is noticeably shorter. |
Items to be checked at commissioning and handover
- For each device, measured signal level and acceptance report containing redundant path information.
- Device–address–location list; because wireless devices are portable, this list is more critical than in wired systems.
- Battery type, quantity, and planned replacement schedule.
- Extender and repeater positions marked on the plan.
- Demonstration to operations staff of how communication interruption and battery fault appear on the panel.
Project and product
For wireless smoke detector, wireless call point, siren-sounder and wireless extender modules, see our fire detection products ; to have signal measurement performed in your building and determine actual device and repeater count, see contact us. For introductory explanation of the topic, see our article on wireless detection; for specification equivalent of wired addressed installation, see addressed fire detection specification .
Frequently Asked Questions
Is a wireless fire alarm system safe?
Radio-linked components are evaluated within the EN 54-25 scope, and this scope requires that communication interruption be reported as a fault, battery depletion be announced in advance, and the system does not lose function if a single path fails. If the product performance statement includes EN 54-25, it stands on equal ground with its wired equivalent in terms of security.
Is a wireless fire alarm system cheaper than a wired system?
Per-device cost is higher. The gain does not come from cable cost, but from the expense of cable installation: broken plaster, closed floors, stopped production, intervention on historical surfaces. In small new buildings where these items are minimal, the wired system remains more economical overall.
How long does a wireless detector battery last?
Catalog values are specified for a given communication frequency and ambient temperature. Detectors that dwell in weak signal areas and serve as repeaters for other devices experience significantly shortened operating life. For this reason, battery replacement is planned by device groups rather than waiting for individual device failures.
Can I add wireless devices to my existing wired system?
Usually yes. The common solution is hybrid installation: a wireless expander is connected to the existing wired loop, and devices in the area where cable cannot be run communicate through this module. Devices still appear as addressed points on the panel. Compatibility of the expander brand and loop protocol, as well as positioning determined by measurement, are mandatory.
How is fire detection performed in historical buildings?
In protected structures, surface intervention is often limited; opening channels, drilling holes, and running cable ducts may not be permitted. Wireless devices stand out in such buildings because they can be mounted with minimal contact. Beam-type detectors are also a frequently used alternative because they limit wiring to two endpoints; the two are evaluated together.
How many repeaters are needed in a wireless system?
It cannot be determined by looking at a floor plan. Reinforced concrete walls, metal cladding, fire doors, and elevator shafts attenuate signal very differently; the required number can only be determined by conducting actual signal measurements with devices in the building. Wireless quotations given without measurement almost always increase during installation.
Does a wireless system work in a warehouse?
It works but requires caution. Coverage in a warehouse varies based on shelf occupancy; measurement taken in an empty warehouse does not represent a full warehouse. Metal stock and high shelving reflect signal and can create dead zones. In large-span warehouses, repeater count increases rapidly, so a wired loop is often more suitable.