Hydrostatic Pressure Testing

Hydrostatic pressure testing is a non-destructive method of finding leaks or verifying strength and durability in pressure vessels such as pipe, tubing, and coils by completely filling the test piece with liquid, removing the air contained within the unit, and pressurizing the piece, then holding the pressure for a specific amount of time to examine the system for leaks or permanent changes in shape. A weakness in the structural integrity of a pipe could dramatically impact both the environment and our economy. It is necessary to conduct hydrostatic pressure testing on the vessels involving the storage and transportation of fuel, chemicals, and other hazardous materials which can explode if they fail under pressure.

STEMart performs hydrostatic pressure testing on a wide range of pressure vessels, pipework, components, and systems to assess their suitability for future service.

Test Methods

• Water jacked method: The test vessel filled with water is placed into a sealed chamber (called the test jacket) which is also filled with water. The pressure inside the vessel causes vessel to expand within the test jacket, which forces the water out into a glass tube. The volume of the water indicates the total expansion of the vessel. Once the total expansion is recorded, the vessel is depressurized and shrinks to its approximate original size. As the vessel deflates, water flows back into the test jacket. The volume of water which remains in the glass tube indicates the permanent expansion.
• Direct expansion method: The test vessel is filled with a specified amount of water and then pressurized. The amount of water forced into the vessel and the water expelled once the pressure is released is recorded to measure the permanent expansion and the total expansion values.
• Proof pressure method: The test vessel is applied with an internal pressure and then is checked if it has any leaks or other weakness such as wall thinning that may lead to failure.

Test Material Types

For more information about our hydrostatic pressure testing, please contact us.