If there is a break in a single-wire continuous-loop fire detector element, and the system tests bad, will it indicate the presence of a fire?

If there is a break in a single-wire continuous-loop fire detector element, and the system tests bad, will it indicate the presence of a fire?

• A. Yes, it will indicate presence of a fire.
• B. No, it will never indicate a fire.
• C. Only if the other detector also indicates fire.
• D. It will indicate the presence of a fire only during maintenance.

Answer: (A)

In a single-wire continuous-loop detector, the loop is continuously supervised so that any interruption is quickly noticed. If a break occurs in the detector element, the loop can no longer be monitored properly, and the system’s self-test will flag that condition as a fault. To avoid missing a real fire when detection is compromised, many designs escalate a fault in a monitored loop to an alarm state. That safety approach means a broken loop, when the test indicates bad, will still produce a fire indication at the panel. The other detectors don’t have to participate for this alarm to occur, and it isn’t limited to maintenance time.

In a single-wire continuous-loop detector, the loop is continuously supervised so that any interruption is quickly noticed. If a break occurs in the detector element, the loop can no longer be monitored properly, and the system’s self-test will flag that condition as a fault. To avoid missing a real fire when detection is compromised, many designs escalate a fault in a monitored loop to an alarm state. That safety approach means a broken loop, when the test indicates bad, will still produce a fire indication at the panel. The other detectors don’t have to participate for this alarm to occur, and it isn’t limited to maintenance time.