how to perform hydrostatic test for pressure vessel?

Performing a hydrostatic test on a pressure vessel is a crucial step in ensuring its safety and integrity. This test involves filling the vessel with a liquid, typically water, and pressurizing it to a specified level to check for leaks and confirm that it can safely withstand its rated pressure. Here are the steps to perform a hydrostatic test on a pressure vessel:


Ensure that the pressure vessel is clean and free of any debris, corrosion, or contaminants that could interfere with the test or damage the vessel.

Verify that all openings, including valves and vents, are properly sealed and closed.

Safety Precautions:

Ensure that all personnel involved in the test are trained in safety procedures and are wearing appropriate personal protective equipment (PPE).

Establish a safe working area around the pressure vessel and secure it to prevent unauthorized access.

Make sure there are appropriate emergency response measures in place, including access to first-aid equipment and emergency shut-off procedures.

Select Test Pressure:

Determine the test pressure based on applicable codes, standards, and design specifications. The test pressure is usually a percentage (e.g., 1.5 times) of the vessel’s maximum allowable working pressure (MAWP).

Fill the Vessel:

Fill the pressure vessel with the test fluid, typically water. Ensure that the water is clean and free of any contaminants.

As you fill the vessel, vent any trapped air to prevent air pockets, which can affect the accuracy of the test.


Gradually increase the pressure inside the vessel to the specified test pressure. This can be done using a hydraulic pump, air compressor, or other suitable means.

Monitor the pressure gauge closely to ensure a controlled and gradual increase in pressure.

Hold Period:

Maintain the test pressure for a specified duration (often 30 minutes to 2 hours) while continuously monitoring for pressure fluctuations and any signs of leakage.


Visually inspect the entire pressure vessel for any signs of leakage, including welds, seams, and connections.

Use soapy water or another suitable method to detect even small leaks; bubbles will form at leak points.

If any leaks are detected, release pressure immediately and address the issues before retesting.

Pressure Release:

Gradually release the pressure from the vessel once the test is complete. This should be done slowly and controlled to prevent sudden depressurization.

Drain the Vessel:

Drain the test fluid from the pressure vessel, ensuring it is disposed of properly.


Maintain detailed records of the hydrostatic test, including test pressure, duration, temperature, and inspection results.

Ensure that the vessel is labeled with the test information, including the date of the test and the responsible parties.

Review and Certification:

Have a qualified inspector or engineer review the test results and certify the vessel’s safety and compliance with relevant codes and standards.


After successfully passing the hydrostatic test, the pressure vessel can be recommissioned for service.

Always consult applicable codes, standards, and regulations for specific requirements and guidelines related to hydrostatic testing of pressure vessels, as these may vary depending on the jurisdiction and industry. Additionally, consider involving qualified professionals in the testing process to ensure safety and compliance.

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