A Hydrostatic Test (or Hydro Test) is a verification test method for the strength and leaks of the mechanical component and system after assembled, manufactured, or erected piping and stationary equipment items or systems that will operate under desired conditions. The Hydrostatic Test for the vessel or pipe system is filling up a liquid, usually water as the test medium, and pressuring to the specified test pressure. The Hydrostatic Test is often required after shutdowns and repair works in order to validate under desired conditions.

Reference Definition by whatispiping.com: A hydrostatic test is performed by using water as the test medium, whereas a pneumatic test uses air, nitrogen, or any non-flammable and nontoxic gas. Pressure tests (both hydrostatic and pneumatic) must be performed under controlled conditions, following an approved test plan, and documented in a test record. A single approved test plan could be used for several similar tests, but for each test a separate test record is required.

Related Definitions in the Project: The Construction; Quality Management; Operation and Maintenance