What time should be recorded during a main drain test?

During a main drain test, the time for pressure to return to normal at the end of the test when closing the main drain valve is crucial. This measurement indicates how efficiently the system is able to restore pressure after the drain has been opened.

Monitoring the time it takes for pressure to normalize can provide insights into the overall functionality of the water-based fire protection system, as it suggests whether there are any leaks or restrictions that may be affecting the system's performance. A significant delay in pressure recovery, for example, could indicate underlying issues that need to be addressed to ensure the system operates effectively in the event of a fire. Thus, recording this specific time is essential for evaluating the reliability and efficiency of the system after the test is completed.