If a door release detector is listed for door frame mounting, how many detectors are required if installed according to the manufacturer's published instructions?

If a door release detector is listed for door frame mounting, how many detectors are required if installed according to the manufacturer's published instructions?

• A. 2
• B. 3
• C. 4
• D. 1

Answer: (D)

When a detector is listed for door frame mounting, the listing shows that a single device installed in the door frame is enough to monitor the door release as designed. Following the manufacturer’s published instructions is the guiding rule, and in this case that guidance specifies one detector to fulfill the monitoring requirement. Using more detectors would not only be unnecessary but could also conflict with the listing and complicate the system, without improving reliability. So, one detector is the correct approach because the frame-mounted device is designed and tested to perform its function from that single mounting point.

When a detector is listed for door frame mounting, the listing shows that a single device installed in the door frame is enough to monitor the door release as designed. Following the manufacturer’s published instructions is the guiding rule, and in this case that guidance specifies one detector to fulfill the monitoring requirement. Using more detectors would not only be unnecessary but could also conflict with the listing and complicate the system, without improving reliability. So, one detector is the correct approach because the frame-mounted device is designed and tested to perform its function from that single mounting point.