Linear Heat Detection Systems
BS 5839-aligned linear heat detection for environments where conventional point detection isn’t practical, reliable or sufficient. Cable trays, underground tunnels, conveyor systems, car parks, warehouses and industrial process areas, designed, installed, commissioned and maintained by WSD’s own engineers.
Linear heat detection is a specialism most generalist fire contractors won’t take on. We do. It’s a discipline that needs the design done properly, the cable installed cleanly, and the integration with the main fire alarm panel programmed precisely. Our engineers handle all three.
Linear heat detection (LHD) uses a continuous sensor cable run along the length of the area being protected, rather than discrete detection points spaced at fixed intervals. When the temperature anywhere along the cable rises above a defined threshold, the system identifies the alarm condition and signals the main fire panel.
That continuous coverage is what makes LHD the right answer for environments where point detectors don’t work:
- Long, narrow runs – cable trays, service ducts, tunnels, conveyors – where point spacing would miss the gaps
- Inaccessible locations – underground tunnels, sealed voids – where servicing point detectors is impractical
- High dust or harsh conditions – waste facilities, industrial processes – where conventional smoke detection contaminates quickly
- Large open volumes – warehouses, car parks – where point coverage becomes excessive
- High air movement – tunnels, plant rooms with significant ventilation – where smoke doesn’t accumulate predictably
In short: where the geometry, environment or accessibility makes conventional smoke or heat point detectors unreliable, LHD is usually the right call.
Linear heat detection systems we install
We install and maintain LHD systems from the leading manufacturers in the discipline:
- Protectowire – one of the established benchmarks for digital and analogue linear heat cable
- Thermocable – UK-manufactured linear heat detection systems
- Patol – widely specified across industrial and commercial UK installations
- Safe Fire Detection – including specialist sensor cable applications
- Kidde – integrated detection systems
- FFE (Honeywell) – flame and heat detection systems
- Other approved specialist linear heat detection systems where the project requires it
Product selection is driven by the environmental conditions, the specific fire risk profile of the application, and the project specification. The cable for a high-temperature foundry process is a different choice from the cable for a chilled cold-store conveyor or a low-temperature cable tray.
Design, install, commission and integrate
We deliver the complete LHD service end-to-end. The same engineers handle design through to handover. Nothing is sub-contracted out.
Design
Either to a consultant’s specification or as a fully designed solution. Cable routing, panel selection, interface design and cause-and-effect strategy.
Installation
Cable laid, terminated and fixed by our own engineers, with proper attention to bend radii, fixing intervals, expansion provision and environmental protection.
Integration
Interface modules wired into the fire alarm panel, BMS, suppression and any other linked systems.
Commissioning
End-to-end functional testing, alarm verification, fault simulation, cause-and-effect testing across the full programmed matrix.
Handover documentation
As-fitted drawings, commissioning records, BS 5839 compliance documentation, asset register, O&M manual and maintenance recommendations.
Got questions? We've answered the common ones.
Quick answers on cover, callout times, accreditations and what working with us actually looks like. Still got a question? Get in touch.
What is linear heat detection?
A fire detection method that uses a continuous sensor cable run along the length of an area, rather than discrete point detectors at fixed spacings. When the temperature anywhere along the cable rises above a defined threshold, the system signals the main fire panel. It gives reliable coverage in environments where point detection isn’t practical: cable trays, tunnels, conveyors, warehouses, car parks, industrial processes.
How does linear heat detection work?
The sensor cable contains conductors separated by a heat-sensitive insulating material. When the temperature reaches the cable’s rated alarm threshold (typically 68°C, 88°C or higher depending on the application), the insulation breaks down and the conductors short, triggering the alarm signal. Digital cables register the exact location of the activation along the cable run; analogue systems indicate which zone has alarmed.
Linear heat vs point detection – which do I need?
Point detection (smoke or heat detectors at fixed spacings) is the default for most enclosed rooms and standard commercial spaces. Linear heat detection becomes the right answer where point spacing wouldn’t reliably cover the geometry (long narrow runs), where the environment makes point detectors unreliable (dust, vapour, high airflow) or where the location is too inaccessible for routine point detector maintenance. Many sites use both: point detection in occupied areas, LHD in plant rooms, cable trays and process areas.
Can you integrate LHD with our existing fire alarm panel?
Yes. LHD systems are routinely integrated with existing addressable or conventional fire alarm panels through interface modules. The integration also extends to suppression release, smoke control, plant shutdown, BMS and remote monitoring where required.
Which manufacturers do you install? (LHD)
Protectowire, Thermocable, Patol, Safe Fire Detection, Kidde, FFE (Honeywell) and other approved specialist systems where the project specification calls for them.
How often does linear heat detection need to be tested?
Routine LHD testing is aligned to BS 5839 recommendations alongside the wider fire alarm maintenance regime. For most installations that means an annual full functional test as part of the fire alarm service contract, with interim checks where the environment or risk profile warrants it.
Do you cover the whole UK?
Yes, we deliver maintenance contracts and projects nationally from our Bromsgrove HQ. Most of mainland Britain is within a routine response window for reactive maintenance work.
Sites further from the Midlands may have slightly longer response windows for reactive call-outs; we can provide a map of typical response times by area during the initial survey if it’s relevant to your site.