What is the closure step in the main drain test?

The closure step in the main drain test involves closing the valve. This step is important as it involves sealing off the drain to measure the system's ability to maintain pressure and ensure there are no leaks or weaknesses in the piping system or any connected components. The closure of the valve helps in determining whether the system can hold the water and whether the shut-off features are functioning properly.

In the context of fire protection systems, this step is crucial for testing the effectiveness and reliability of the water supply in the event of a fire. By observing how the system reacts when the main drain is closed, one can gather valuable data regarding its integrity and performance capabilities.