Heat detectors include the following types EXCEPT

• A. Rate-of-Rise
• B. Fixed Temperature
• C. Differential
• D. Deluge

Answer: (D)

Understanding how heat-detection works: heat detectors sense temperature changes, but they do so in different ways. Fixed-temperature detectors trigger when the ambient temperature reaches a specific threshold. Rate-of-rise detectors respond to a rapid increase in temperature, signaling a fire even if the absolute temperature isn’t yet very high. Differential detectors monitor a temperature difference between two points to catch abnormal heating more quickly than a single-temperature sensor alone.

Deluge, on the other hand, is a type of fire suppression system configuration where water is discharged through all sprinkler heads when the system is activated. It is part of the suppression gear, not a device that detects heat. So it isn’t a heat detector, which is why it’s the correct choice for the item that doesn’t belong among heat detectors. The other three options are heat detectors by their operating principles.