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Linear Heat Detectors: Safeguarding Diverse Environments

Linear heat detectors (LHD) have emerged as a crucial technology in fire detection and prevention, offering a versatile and reliable solution to safeguard various environments. Unlike traditional point detectors, linear heat detectors provide continuous monitoring over extended lengths, making them ideal for multiple applications.

Understanding Linear Heat Detectors

Linear heat detectors operate on the fundamental principle of detecting temperature changes along a continuous cable length. These cables are designed with a heat-sensitive element that reacts to increases in temperature, triggering an alarm when a predefined threshold is surpassed. Linear heat detectors are typically wired directly into a fire alarm control panel (FACP) or a fire detection and suppression system, allowing them to communicate with the panel and trigger appropriate responses in case of a temperature increase or fire hazard. The detection technology can be broadly classified into two main types: digital and analogue.

Digital Linear Heat Detectors

Digital linear heat detectors operate on a binary principle—either triggered or not triggered. These detectors are characterised by discrete zones, each with its own set temperature threshold. Digital detectors are often used in environments where distinct zones or areas require individualised temperature monitoring.

Analogue Linear Heat Detectors

Analogue linear heat detectors provide a more granular approach to temperature sensing. Unlike digital detectors, analogue variants can monitor temperature changes continuously along the entire length of the cable. This allows for a more precise identification of the location and severity of a temperature increase. Analogue detectors are commonly employed when a more nuanced understanding of the thermal environment is crucial.

Applications of Linear Heat Detectors

Linear heat detectors find diverse applications across various industries due to their adaptability and effectiveness in detecting potential fire hazards. A few key applications include:

Parking Garages

Fire hazards in parking garages are multifold, ranging from vehicle fires and flammable liquids to electrical faults and deliberate acts of arson. Smoking, littering, malfunctioning HVAC systems and electric vehicle charging stations also pose a risk. Linear heat detectors, strategically installed, offer a proactive solution. By continuously monitoring temperature changes, they swiftly identify potential fire risks.

Tunnel Fire Detection

Linear heat detectors are extensively used in tunnels to enhance fire detection capabilities. The extended length coverage makes it feasible to monitor large tunnel structures effectively and provide early warnings to mitigate potential disasters.

Petrochemical Industry

The petrochemical industry relies on linear heat detectors to monitor critical areas such as storage tanks and processing units. Continuous monitoring helps in early fire detection, reducing the risk of catastrophic incidents and ensuring the safety of personnel and assets.

Power Generation Plants

In power generation plants, linear heat detectors play a vital role in monitoring critical equipment, electrical panels, and cable trays. The continuous monitoring capability helps identify overheating issues before they escalate, ensuring the reliability of the electrical infrastructure.


Linear heat detection plays a critical role in enhancing fire safety measures in electrical substations. These high-risk environments, characterised by the presence of electrical equipment, transformers, and intricate wiring, are susceptible to fire hazards. Linear heat detectors, strategically deployed in substations, provide continuous temperature monitoring along extended cable lengths. This allows for early detection of overheating issues, electrical faults, or equipment malfunctions that could lead to fires.

Solar Panel Installations

Linear heat detectors are increasingly finding application in solar panel installations. Monitoring temperature changes in and around solar panels is critical to prevent potential fire hazards. The extended coverage of linear heat detectors ensures comprehensive monitoring, enhancing the safety of solar energy systems.

Some installation considerations for linear heat detectors

Familiarise yourself with local regulations, codes, and standards relevant to linear heat detector installations. Compliance with these standards is crucial for ensuring the effectiveness and legality of the system. Plan the cable routing carefully, considering the space layout and potential fire risks. Ensure that the linear heat detector cables cover all critical areas and are installed in locations where they can effectively detect temperature changes. Cable management is key; therefore, the cables should be securely installed and properly supported using suitable clips, clamps, or other approved methods to prevent sagging or damage. It is advisable that a thorough site survey is conducted at the start of your project to identify the areas that require linear heat detection. The survey should also consider the installation area's layout, environmental conditions, and potential fire hazards. The ADI Support Services Team is always on hand to help you with your site survey and any other installation issues.

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