What does a pressure supervisory signal for a dry pipe sprinkler system indicate?

A pressure supervisory signal for a dry pipe sprinkler system indicates both high- and low-pressure conditions. This type of signal is essential for monitoring the integrity of the system and ensuring that it is ready for operation. In a dry pipe system, the pipes are filled with air or nitrogen rather than water, and water is released only when a sprinkler head operates. The pressure supervisory system alerts to any abnormal pressure conditions that could affect the system's readiness.

If the pressure drops too low, it may indicate a leak or another problem that needs to be addressed to ensure reliable operation during a fire event. Conversely, high pressure could indicate system malfunctions or over-pressurization that also needs immediate attention. Thus, monitoring both ends of the pressure spectrum helps maintain the system's functionality and safety effectively.

Other choices do not fully encompass the purpose of the supervisory signal; for instance, water pressure only would not indicate potential issues that could compromise the system. Similarly, flow of water and pump activation status pertain to very specific operational conditions, rather than the overall readiness that the supervisory signal aims to monitor.