What does a pressure supervisory signal indicate when it detects a change?

A pressure supervisory signal is an essential component in fire protection systems, particularly in relation to the integrity of sprinkler systems and standpipes. When a change in pressure is detected, it typically indicates that there may be a potential issue with the system, such as a leak or other malfunction. This is crucial because pressure loss can impair the effectiveness of the fire protection system, leading to possible system failure during an emergency.

In this context, the detection of a change signals that something is wrong within the system that could affect its operation. Therefore, interpreting the supervisory signal as an indication of potential system failure aligns with the purpose of monitoring pressure—ensuring that firefighting systems are operating effectively and can respond when needed.

The other options do not accurately represent the implications of a change in pressure. For instance, a normal operating condition would not trigger a supervisory signal, nor would scheduled maintenance be indicated directly by a pressure change. Additionally, fire alarm activation is a distinct event not related to pressure variations within the system. Thus, identifying the supervisory signal as indicative of a potential system failure is fundamentally aligned with the proactive approach of maintaining fire safety systems.