Alarmline Linear Heat Detection (LHD) is a cable based system that provides economical temperature monitoring at the precise point of risk. The system is reliable, flexible and has the ability to detect abnormal temperature variances before fire breaks out.

The comprehensive LHD portfolio allows a wide range of commercial and industrial fire and overheats risks to be protected, in ambient temperatures of -40°C to +200°C.

Alarmline is especially suitable for confined areas or harsh environment, where other types of detector are not an option.


  • Detection at point of risk.
  • Provides a fast response.
  • Economical, simple and easy to install.
  • Minimal maintenance.
  • Long service life.
  • Electrical and mechanical flexibility.
  • Suitable for hazardous areas, using approved Zener Barriers or Galvanic Isolators.
  • Able to work in conjunction with interposing cables.
  • Integration with fire extinguishing systems, control and monitoring systems.



Alarmline cables provide protection over a wide range of applications. They are installed close to risks, provide best coverage and ensure rapid detection.

  • Cable trays and risers
  • Escalators
  • Conveyor belts
  • Road tunnels
  • Covered/ underground car parks
  • Rack storage
  • Floating roof tanks
  • Engine bays
  • Transformers

and many more

Product Range


Digital Cable

Employing a twin conductor switching cable, the Alarmline Digital cable operates by melting of internal insulation between the conductors at a predetermined temperature. This results in a short circuit which provides a fire alarm signal. Fault conditions are detected by continuous monitoring for an open circuit state.


Analogue Cable

Alarmline Analogue cable is a four-conductor flexible cable, and senses temperature variations by continuously monitoring the resistance of specially doped Negative Temperature Coefficient (NTC) polymeric insulation. A change in temperature produces a relative change in resistance which is monitored by an Alarmline controller, allowing continuous monitoring for fire and open/short circuit faults.