How should you prepare a boiler before a hydrostatic test?

Preparing a boiler for a hydrostatic test is a critical step to ensure safety and effectiveness. The correct approach involves locking and tagging all valves. This action is essential because it prevents any accidental operation during the test, which could lead to dangerous situations or compromised test results.

When a hydrostatic test is performed, the boiler is filled with water and subjected to pressure beyond its normal operating conditions. If valves remain in an open or partially open state, the pressure can escape, leading to inaccurate test readings or potentially catastrophic failures. Locking and tagging all valves helps ensure that they remain in the desired position throughout the duration of the test, maintaining system integrity.

In contrast, draining all water and leaving the boiler empty is not appropriate for a hydrostatic test, as the test requires the boiler to be filled with water to assess its integrity under pressure. Filling the boiler with oil is also incorrect, as hydrostatic tests specifically use water. Heating the boiler to maximum pressure should not occur prior to a hydrostatic test since the test itself will determine the boiler's ability to withstand pressure without leveraging heat. Thus, the practice of locking and tagging valves is crucial to maintaining a safe testing environment.