What Is Digital Type Linear Heat Detection System?

Digital Type Linear Heat Detection System (LHDS) is a device in which detection is continuous along a path. It is designed to provide an early detection of fire and overheating in situations where other forms of detection would not be practical. The linear heat detector cable is capable of sensing heat anywhere along its length, initiating an alarm once its fixed activation temperature has been reached. When the ambient temperature meets or exceeds the detector peaks temperature the heat-sensitive insulation that is softens allows the wires to make electrical contact, initiating an electrical short triggering an alarm.

Composition Of Linear Heat Detector Cable

• Steel Conductors – composed of (a) steel, to provide tensile strength, (b) copper, to increase conductivity, and (c) tin, to resists corrosion
• Protective Tape – advanced insulation provides temperature specific activation, it softens on certain temperature
• Outer Jacket – comes with 4 jacket types for various 

Applications and environments

a.EPC & CTI (Polyvinyl Chloride) – ideal for general, multi-purpose applications

b.Type XCR & CTI (Fluoropolymer) – ideal for extreme environments and includes excellent resistance to chemicals and UV.

c.Type XLT (Proprietary Polymer) – ideal for low temperature such as cold storage

d.Type PLR (Polypropylene Elastomer) – ideal for outdoor applications

Advantages Of Linear Heat Detector Cable

• Detects heat at any point along its length
• Minimal false alarms
• Easy installation and low maintenance
• Can be installed near to hazards
• Can be use in extreme conditions and can resist corrosion, hemicals, moisture and extreme temperatures
• Long life span

The detector can be used with any domestic and foreign manufacturers of fire alarmcontroller connection glance at automatic fire detection system, which can effectively protect the following objects:

• Cable facilities: cable tunnel, shaft, mezzanine,cable tray, etc:
• Electric utilities: distribution equipment, switchgear, transformers and reactors;
• Oil, gas, hydraulic, lubricating oil storage, oil tank, gas tank, oil boilers, gas boilers, fuel injection(baked) booth:
• Belt transmission facilities, coal delivery, transport belts and automated production lines.

Linear Heat Detection System Design Parameters

On smooth ceilings installation, the distance between parallel detector runs shall not exceed the maximum listed spacing there, shall be a detector run within a distance of ½ listed spacing measured at a right angle from all walls or partitions that extend to within top 15% of the ceiling height.

On solid joist ceiling installations, with open joists or other similar structures heat travels freely down the joists channel, however heat has trouble spreading across the joists, so the distance in this direction must be reduced the linear heat cable detector shall be mounted on the bottom of the joists and the spacing of the detector on all runs measure at right angles parallel to the joists shall not exceed 50% of the smooth ceiling spacing, on runs the parallel both joists and wall the spacing shall not exceed 25%

On solid beam ceiling installations, in the case of beam construction, where the beams are 4” or less in the depth, the ceiling shall be treated the same as a smooth ceiling. If the beams project more than 4” below the ceiling, the spacing at right angles to the direction of beam travel shall not exceed 2/3 of the smooth ceiling spacing.

How To Testing Linear Heat Detection System

1.Fixed-temperature, rate-of-rise, rate-of-compensation, restorable line, spot type (excluding pneumatic tube type)

oHeat test shall be performed with a heat source per the manufacturer’s published instructions for the installed equipment, or other method shall be used that will not damage the non-restorable fixed temperature element of a combination rate-of-rise or fixed-temperature element detector.

2.Fixed-temperature, non-restorable line type (Protectowire)

oHeat test shall not be performed. Functionality shall be tested mechanically and electrically. Loop resistance shall be measured and recorded. Changes from acceptance test shall be investigated.