BS 5839 is the British Standard that sets out the guidelines for designing, installing, commissioning, and maintaining fire detection and alarm systems in buildings, ensuring they are reliable and suited to the specific risks of the premises.
BS 5839 is typically reviewed and updated every 5 to 10 years, but updates can occur sooner if significant industry changes, new technologies, or safety concerns arise.
BS 5839‑1:2025, which came into effect on 30 April 2025, updates the 2017 edition with clearer guidance and enhanced safety measures—extending detection to lift shafts and low-risk lobbies, requiring distinct lockdown tones, 90-second signal monitoring, updated battery backup calculations, and mandatory red mains cable labelling; it also reinforces maintenance protocols by mandating 6-month service flexibility (5–7 months), CPD for engineers, battery recording, clock sync, zone chart updates, and removal of obsolete components, along with refreshed certification templates, a new section for system modifications, and modernised terminology to improve inclusivity and clarity.
But that is not all. BS5839-1:2025 now also makes specific mention of the latest Linear Heat Detection standards BS EN 54-22 and BS EN54-28.
What are BS EN 54-22 and BS EN 54-28?
A BS EN standard ensures the UK uses the same technical and safety requirements as other European countries, promoting consistency, quality, and easier trade across borders.
For example, BS EN 54 is a widely used European standard for fire detection and alarm systems.
BS5839-1:2025 makes specific mention of using Linear Heat Detection in enviornmentally harsh areas. e.g car parks, watch our explainer here
What Does BS5829-1:2025 say about using Linear Heat Detection?
The 2017 BS5829 revision recognised Linear Heat Detection as a suitable alternative to point-type heat detectors, particularly in areas where environmental conditions (e.g. dust, high ceilings, or heat) make point detectors unsuitable.
Clause 22.3(l) of BS 5839-1 notes that linear heat detection may be used in difficult environmental conditions, such as cable tunnels, industrial spaces, and transport infrastructure.
However, the BS5839-1:2025 revision makes clear recommendation for using Linear Heat Detection in enviornmental harsh conditions and will lead to less unwanted and false alarms (clause 33.2.2)
Which applications should Linear Heat Detection be used in?
Linear heat detection should be used in environments where traditional point detectors are unsuitable, such as:
Harsh or dirty environments (e.g. tunnels, factories, cable trays)
Areas with high ceilings or long distances (e.g. warehouses, conveyors)
Hazardous or explosive areas
Outdoor or exposed locations
When early heat detection along a continuous path is needed
It’s ideal where precise, continuous temperature monitoring is critical and conditions may affect standard detectors.
For examples of where Signaline Linear Heat Detection can be used please check out our applications pages.
Which Signaline Linear Heat Detection cables are approve to BS5839-1:2025?
Please note that BS5839-1 is an installation standard and not a product standard. However, to comply to the installation standard approved products must be used. BS5839-1:2025 makes specific mention of BS EN54:22 and BSEN54:28 as discussed above.
Our approved products to these standards are as follows
Signaline HD+ is our Programmable Linear Heat Detector that is approved to EN54:22 (please click here for the certificate)
Signaline FT-EN is our Non-Resettable Linear Heat Detector that is approved to EN54:28 (please click here for the certificate)
Signaline HD+ Programmable Linear Heat Detector is EN54 part 22 approved
Summary
BS 5839-1:2025 is the updated British Standard for fire detection and alarm systems, effective from 30 April 2025. It offers improved guidance on system design, installation, commissioning, and maintenance, with a focus on enhanced safety and clearer requirements. The revision formally references BS EN 54-22 and BS EN 54-28, endorsing Linear Heat Detection (LHD) for challenging environments like tunnels and hazardous areas. Approved products such as Signaline HD+ and Signaline FT-EN are recommended to ensure compliance.
For further information on BS5839 or on our Signaline Linear Heat Detection cables please contact sales@lgmproducts.com
Signaline is very proud to announce the launch of its latest innovative linear heat detection cable; Signaline HD+
Signaline HD+ is a smart solution for linear heat detection. It uses a special sensor cable that monitors for temperature changes along its whole length.
This means it provides ongoing and full monitoring. Thanks to this technology, it can quickly find any rise in heat, which may point to a fire risk.
Signaline HD+ is very sensitive. It can catch even the smallest changes in normal temperature. This helps with quick action to prevent fires.
Approved to EN54 part 22, by VdS, and UL approved, Signaline HD+ is Signaline’s first globally approved product.
Used in combination with the programmable linear heat detection controller Signaline HD+ can be set to variable alarm and pre-alarm temperatures.
Signaline HD+ is available in standard pvc, nylon or stainless steel braiding
What is a Programmable Linear Heat Detector?
Linear heat detection is a simple and easy to use form of heat detection. It utilizes a temperature sensitive cable and control unit to indicate if over-heating has occurred in the protected area.
Signaline now offers both resettable and non-resettable linear heat detection.
Non Resettable linear heat detection, such as Signaline FT or Signaline FT-EN, uses a two core cable that will activate at a certain temperature. Once activated the length of cable in alarm will need replacing.
Whereas Signaline HD+ will return to a normal state after an alarm event providing the cable hasn’t been damaged.
What makes Signaline HD+ programmable is that it has the capability to have set pre-alarm and alarm temperatures.
Meaning that you can tailor the linear heat detection to the required specification of the area that you are protecting.
Signaline HD+ Controller and End of Line Complete the system and allow for user selectable alarm temperatures
What are the benefits of Programmable Linear Heat Detection?
Linear Heat Detection is unique in being a detector in cable form. Meaning you can run cable into areas that other fire detections devices cannot go. For example, running linear heat detection around car parks or solar panels is a very affective form of heat detection.
Signaline HD+ has a number of additional benefits compared to current Linear heat detection products.
Firstly, the programmable alarm temperature allows installers to set specific alarm and pre-alarm temperatures. Ensuring that any over-heating is detected and reported at the earliest opportunity.
The construction of the cable also ensures protection against environmental factors like moisture, dust and saline environments, eliminating false alarms.
Being available in various outer coatings allows Signaline HD+ to be used in nearly any application regardless of environmental conditions
Signaline HD+ is also UL approved and carries EN54 part 22 approval from VdS. This dual approval allows this product to be used across European and global markets.
With easy fire and fault connections Signaline HD+ programmable linear heat detector can be connected to any fire detection system or used as a stand-alone over-heat detector for special applications.
Where do you use programmable linear heat detection?
Linear heat detection is not affect by environmental conditions. Therefore it is a perfect solution for fire detection in environmentally challenging conditions.
For example, car parks are often exposed to moisture, dust and exhaust fumes. Yet, as seen in recent car park fires in Luton airport or Liverpool arena, fire detection in these environmentally difficult areas is imperative.
Other applications for Signaline HD+ Programmable Linear Heat Detection include –
False ceilings void – Signaline HD+ can be placed in the space between the hard constructed ceiling and false ceiling.
Industrial kitchens – where fluctuations in ambient temperature and environmental gases and oil are to be expected programmable linear heat detection is an excellent solution to detect over heating conditions
Escalators and moving walkways – hard to access and with likely mechanical risks using Signaline HD+ can be used to ensure detection of any over heating
Recycling centers – the mixture of materials that converge at recycling centers can lead to an increase risk of fire. Signaline HD+ is not affected by environmental conditions and can provide affective early warning of over heating
Power cables – from renewable to non-renewable power generation, power cables are critical to modern day infrastructure. Often exposed and in unmanned areas power cables can be a source of fire. Signaline HD+ programmable linear heat detection will pick up the early increases in temperature across power cables.
Combined with our range of high quality and EN54 compatible fixing and installation accessories such as the Q clip, Signaline HD+ will always be the right choice for fire detection and increased compliance.
