________ detector is one which responds to rapid changes in temperature?

• A. Disk-Thermostat
• B. Infrared
• C. Bimetallic
• D. Rate of Rise

Answer: (D)

Rate of rise detectors focus on how fast the temperature increases. They trigger when the temperature climbs rapidly within a short period, regardless of the final temperature reached. This makes them ideal for catching rapidly developing fires that heat the surroundings quickly. Fixed-temperature detectors like disk-thermostats and bimetallic devices only react when the ambient temperature hits a set point, not how quickly it gets there. Infrared detectors sense radiant heat energy, which is a different sensing principle from tracking the rate of temperature change. So, when the detector’s response is about rapid temperature changes, the rate-of-rise type is the best fit.