Which type of heat detection uses two steel conductors coated with a heat-sensitive polymer that melts away to allow contact?

Which type of heat detection uses two steel conductors coated with a heat-sensitive polymer that melts away to allow contact?

• A. Rate-of-rise
• B. Line-type
• C. Spot-type
• D. Fiber-optic

Answer: (B)

Line-type heat detectors monitor a length of area by using two metal conductors with a heat-sensitive polymer coating between them. When the ambient temperature reaches the detector’s set point, the polymer melts away, allowing the two conductors to contact and complete the circuit, which triggers the alarm. This bridging action along a line provides continuous coverage along corridors, aisles, or other long runs. This mechanism is distinct from rate-of-rise detectors, which respond to rapid temperature increases without any contact between conductors; spot-type detectors, which are individual devices with fixed temperature thresholds; and fiber-optic detectors, which sense temperature changes by observing alterations in light signals along a fiber.

Line-type heat detectors monitor a length of area by using two metal conductors with a heat-sensitive polymer coating between them. When the ambient temperature reaches the detector’s set point, the polymer melts away, allowing the two conductors to contact and complete the circuit, which triggers the alarm. This bridging action along a line provides continuous coverage along corridors, aisles, or other long runs.

This mechanism is distinct from rate-of-rise detectors, which respond to rapid temperature increases without any contact between conductors; spot-type detectors, which are individual devices with fixed temperature thresholds; and fiber-optic detectors, which sense temperature changes by observing alterations in light signals along a fiber.