Which detection method measures the rate of temperature increase?

• A. Fixed temperature
• B. Rate of rise
• C. Smoke
• D. Vapor

Answer: (B)

Heat develops in fires in two ways: how hot it gets and how fast it gets hot. A rate-of-rise detector is designed to monitor how quickly the temperature climbs over time and will trigger when that rate exceeds a set threshold. This means it can alert early in a rapidly developing fire before the temperature reaches a high fixed value. Fixed temperature detectors, on the other hand, wait for a specific temperature to be reached, which can delay warning in fast fires or produce false alarms in hot environments. Smoke detectors respond to smoke particles, not heat, and vapor detectors respond to gases or vapors, which are different hazards. So the detector that measures the rate of temperature increase is the rate-of-rise detector.