How it works
Linear Heat Detection (LHD) is a continuous heat detector designed to detect heat along the length of a sensor cable. This sensor cable is made up of two conductors, both insulated by heat sensitive polymers.
The heat sensitive polymer is protected by an outer jacket. Beneath this jacket and heat sensitive polymer coating is a pair of steel conductors. When the ambient temperature meets or exceeds the detector’s fixed temperature, the polymer melts. As it melts, the steel conductors make contact and initiate an electrical short that then sends a signal to the fire alarm panel of an alarm condition.
Once a signal has been sent, the panel will then release the fire suppression agent or set of the fire alarm system. For example, if the LHD is connected to a fire alarm that initiates the fire sprinkler system upon alarm, when the heat from fire melts the wire, the system is alerted, and the fire sprinkler valves open to allow water to flow in. LHD work with most any type of fire alarm system (wet, dry, etc.).