Equipment supplier Carrier Fire & Security is a global leader in the design, manufacture and distribution of life safety equipment. 

With industry-leading brands and products, the company has pioneered solutions for the modern world borne out of a legacy of knowledge and experience.

AlarmLine II linear heat detection is a cable-based temperature monitoring system that provides detection of abnormal changes in the ambient temperature within commercial and industrial applications. AlarmLine II linear heat detection provides an economical solution for applications where other forms of detection may not be suitable.

The AlarmLine II product range is split into two sub-ranges, AlarmLine II Analogue and AlarmLine II Digital, providing customers and end-users with a range of solutions to meet the requirements of different applications.

The simplest form of linear heat detection, AlarmLine II Digital, is a non-resettable line type heat detector. AlarmLine II Digital consists of a range of twin conductor cables with each cable providing a different alarm temperature rating to meet the requirements of a range of applications. 

The sensor cable is constructed of two cores each insulated with a special polymer which is designed to break down at a specific temperature; the two cores are twisted together creating tension. As the temperature around the cable increases, the insulation breaks down and the tension created by the twists forces the two cores to make contact. The contact between the two cores is detected by the monitoring equipment which then triggers an alarm condition. 

AlarmLine II Digital provides an unrivalled range of five different alarm temperature rated cables to choose from - 68 °C, 88 °C, 105 °C, 185 °C and 218 °C.  It can be interfaced to any main fire alarm system through a monitored zone input without the need for a dedicated control unit. 

The AlarmLine II Digital system can be enhanced by using the AlarmLine II Digital location control unit, which identifies the alarm point along the length of sensor cable that could extend up to 3 km.

Unlike AlarmLine II Digital, the analogue system provides a higher level of control over system operation. AlarmLine II Analogue uses sensor cable which is monitored by a dedicated control unit, changes in the surrounding temperature causing changes in the characteristics of the sensor cable which will activate the control unit at the programmed alarm temperature.

This sensor cable is provided with different protective outer sheaths allowing it to be installed in a wide variety of applications.  AlarmLine II Analogue is a resettable line type heat detector whereby, providing that the cable has not been physically damaged, the system can be reset following an alarm condition.

AlarmLine II Analogue can also provide an early warning through a programmable pre-alarm activation threshold.  A preset range of programmable alarm and pre-alarm thresholds make configuration of the system quick and easy, with no difficult calculations or graphs required.

AlarmLine II Analogue allows for superior detection capability over many competitors’ sensor cables because it compensates for ambient temperature fluctuations. This feature not only ensures better and more accurate detection at the programmed alarm temperature, but also ensures smaller detection areas across the full cable length of up to 500 m. 

AlarmLine II Analogue is easily interfaced with the main fire system using potential free contacts providing for alarm, pre-alarm and fault notifications.  Dedicated control units are provided with or without a liquid crystal display (LCD). These are either programmable on the unit itself (on units with an LCD) or fully configurable through a personal computer.

Fires in densely packed racking, typical in warehousing, can be detected with a localised AlarmLine II detection system.  AlarmLine II can be installed within the racking to provide detection close to the point of risk, providing a discrete detection system which is unaffected by the normal working environment.  It can be zoned within the racking and is often used to trigger the preaction stage of a sprinkler system to ensure rapid detection and control the spread of a fire.

The recommendation is to install AlarmLine II at the ceiling and within the rack, fixing it to the existing shelf supports in a position where it will not be damaged when loading and unloading the shelves. 

The warehouse and racking can be split into zones to reduce the search area and to activate the relevant sprinkler or suppression system. The interface used for monitoring AlarmLine II may be in the detection zone or it may be installed remotely. 

If the interface is to be located remotely, an interposing cable from the interface to the detection zone is required - this is connected to AlarmLine II using a suitable junction box and fire rated cable.

Where a warehouse is used for cold storage and operates at low temperatures AlarmLine II can be used to provide general area protection. The design follows the guidelines for point type heat detectors or is installed as ‘in-rack’ protection.