Which step comes first in conducting the main drain test of automatic sprinkler systems?

The first step in conducting the main drain test of automatic sprinkler systems involves recording the pressure on the system side. This is crucial because it establishes a baseline for the system pressure before any water is discharged or any changes are made. By capturing this initial pressure, you can accurately assess how the system performs under the conditions of the test, monitor any changes that occur during the process, and evaluate the overall functionality of the sprinkler system.

Recording this pressure right away allows for an accurate comparison with the subsequent measurements obtained once the main drain is opened and water is allowed to flow. This is essential for ensuring that the system is functioning properly and that there are no issues that could compromise its effectiveness in a fire event.