What is the detector time constant for a detector at 196°F with a listed spacing of 15 ft?

What is the detector time constant for a detector at 196°F with a listed spacing of 15 ft?

• A. 44
• B. 46
• C. 43
• D. 45

Answer: (D)

The detector time constant is the approximate time a detector takes to reach its triggering condition after heat is introduced, and for heat detectors it comes from a manufacturer chart that links ambient temperature and detector spacing to a response time. Given an ambient of 196°F and a listed detector spacing of 15 ft, the chart used for these calculations yields a time constant of forty-five seconds. This reflects how heat transfer to the sensor and the time to reach the detector’s activation threshold vary with hotter surroundings and the distance to heat sources. If spacing were different or the ambient temperature changed, the time constant would shift accordingly, since those factors change how quickly heat reaches the detector.

The detector time constant is the approximate time a detector takes to reach its triggering condition after heat is introduced, and for heat detectors it comes from a manufacturer chart that links ambient temperature and detector spacing to a response time.

Given an ambient of 196°F and a listed detector spacing of 15 ft, the chart used for these calculations yields a time constant of forty-five seconds. This reflects how heat transfer to the sensor and the time to reach the detector’s activation threshold vary with hotter surroundings and the distance to heat sources.

If spacing were different or the ambient temperature changed, the time constant would shift accordingly, since those factors change how quickly heat reaches the detector.