Frequently Asked Questions
We’ve answered some of the most common questions across our product range below.
For more detailed information, explore our in-depth FAQ overviews by product type.
Linear heat detection is a cable-based type of fire detection. A physical or electronic process occurs within the detection cable and initiates an alarm once the temperature around the cable reaches a certain threshold (i.e. alarm temperature).
Digital linear heat detection cable is often referred to as non-resettable as a physical change takes place in the detection cable once the alarm temperature is reached and the cable must be replaced following a fire or overheat condition. It is constructed of two metal core wires that come into contact at a certain temperature and, in doing so, create a short circuit. This triggers a resulting alarm on the interface unit or fire control panel.
Analogue linear heat detection cable is commonly known as resettable line-type heat detection as the system can be restored following the event of a fire if the detection cable is not exposed to a temperature above 125 ⁰C. Rather than a physical change taking place, the control unit measures for changes in resistance along the entire length of cable. An alarm is triggered once the resistance along the cable falls below a threshold determined by the chosen alarm temperature setting.
One of the main benefits of linear heat detection cable is its versatility. It can be installed in both indoor and outdoor environments and in hazardous areas if required. Please contact Thermocable if you have any installation or design-related questions.
A typical system will consist of:
- Detection cable
- An end of line unit (for each zone of detection cable)
- A control unit or interface unit
Other components such as junction boxes, which used for splicing or connecting two lengths of detection cable together, or non-sensing (‘leader’) cable are also available.
Analogue linear heat detection systems identify fires or overheat conditions by continuously measuring changes in electrical resistance along the detection cable. An alarm is triggered once the resistance along the cable falls below a set threshold.
Digital linear heat detection cable is often referred to as non-resettable as a physical change takes place in the detection cable once the alarm temperature is reached and the cable must be replaced following a fire or overheat condition. It is constructed of two metal core wires that come into contact at a certain temperature and, in doing so, create a short circuit. This triggers a resulting alarm on the interface unit or fire control panel.
Simply connect the linear heat detection cable or interface module / control unit into a conventional fire panel or into an addressable loop using an input/output module. Detailed instructions of how to make the connections should be provided within the installation manual of a linear heat detection system.
Please find the range of settings below:
ProReact EN Analogue = Class A1I / A2I (VdS approved), Class BI (VdS approved), 54⁰C, 64⁰C, 72⁰C, 79⁰C, 86⁰C, 100⁰C
(Other Pre-Alarm temperatures also available).
Yes, this is possible. Please note that two lengths of digital linear heat detection cable should be connected using a junction box.
Yes. For Class A1I / A2I, 54⁰C and 64⁰C alarm settings, the rate-of-rise alarm is activated when 2 to 5% of the sensor cable is heated at more than 15⁰C per minute for more than 3 minutes.
Another key advantage of using linear heat detection systems is that the ongoing testing and maintenance is hassle free and cost friendly. Thermocable recommends that a linear heat detection system is tested once a year following installation to ensure it is operating as expected.
There are now sophisticated methods of testing a linear heat detection system whereas previously users tested systems by simply imitating a fire by heating up a section of detection cable. Whilst this still an effective test method, it is a costly exercise as the section of cable must be replaced following a test. Testing is now frequently incorporated into the design and operation of the end of line units and interface modules or control units. Instructions on how to test will be enclosed in the installation manual of a linear heat detection system.
Please get in touch with us if you require further clarification on testing or maintenance.
Linear heat detection cable is most commonly installed using fixing clips and tie wraps. It is critical that the operating temperature range of the clips used are suitable for the given environment.
Thermocable’s ProReact Accessories are a comprehensive range of metal clips and supports with suitable maximum ambient operating temperatures for any application thus giving our customers piece of mind.
Plastic clips should be avoided as these are likely to have an unsuitable maximum ambient operating temperature.
If digital linear heat detection cable has been exposed to a temperature above its maximum ambient operating temperature or the desired alarm temperature or if analogue linear heat detection cable has been exposed to > 125⁰C, the affected detection cable must be replaced.
We recommend that the affected section of detection cable and 3 metres either side is replaced with new cable and connected to the existing zone using a junction box. Please get in touch if you have any queries on replacing detection cable in an existing system.
This European Standard applies to non-resettable line-type heat detectors consisting of a sensing element using an electrical sensor cable which can be connected to a sensor control unit or either directly or through an interface module to a control and indicating equipment intended for use in fire detection and fire alarm systems installed in and around buildings and civil engineering works.
The ProReact EN Digital LHD cable (various alarm temperatures available), the ProReact Digital Sensor Control Unit (DSCU) and the ProReact Digital End of Line Unit (EOLU) are all listed as components on the system approval certificate.
Please find below the list of components certified according to UL521:
- ProReact Analogue LHD cable – PVC
- ProReact Analogue LHD Cable – Nylon
- ProReact Analogue Control Unit – Self-Programmable inc. EOL unit
- ProReact Analogue Control Unit – Laptop-Programmable inc. EOL unit
Yes, to our knowledge we were the first manufacturer to have a full system (consisting of detection cable, an interface unit and end of line unit) certified according to EN54-28.
They provide a technical basis to assess the performance of construction products and they enable manufacturers to draw up declarations of performance and affix CE and UKCA marking. Products that are resistant to fire or react to fire fall under the definition of construction products in the European Union.
Low smoke zero halogen cables are being increasingly specified and used in environments where smoke and harmful emissions released in the event of a fire could endanger human life. ProReact Plus Digital LHD cable is a low smoke zero halogen, UV stable and hydrocarbon resistant alternative to traditional digital linear heat detection cable.
There are no restrictions in place for the minimum amount of detection cable installed per zone or system.
Each zone of ProReact Digital Linear Heat Detection cable can contain up to 3,000 metres. Two zones of detection cable can be connected into a ProReact Digital Interface Monitor Module allowing the maximum length of detection cable per system to be up to 6,000 metres.
The installation manual and data sheet are available in English, German, Polish and French. Further languages may be available on request.
