Hydrostatic tests are a type of pressure test that works by filling a component with water and removing the air contained in the device to pressure the system up to 15 times the design pressure limit of the device. Hydrostatic tests include filling a tank or pipe system with liquid water and dyes to support visual leak detection and pressure of the tank and pipe to a specified test pressure.

The test begins by filling the component with liquid water until the pressure reaches a certain level.
Detection pressure tests exert pressure internally to determine whether the vessel has leaks or other weaknesses, such as wall thinning, that could lead to failure. Direct expansion methods are permitted in the United States but federal regulations do not require that a permanent total expansion value be recorded.
Hydrostatic test requirements and restrictions for pipelines carrying hazardous liquids are specified in 49 CFR 195 (Lower E) and the requirements and restrictions for natural gas pipelines in 49 CFR 192 (Lower J).1 Hydrostatic tests for pipelines carrying hazardous liquids require testing at 125% of the maximum operating pressure (MOP) for 4 continuous hours and another 4 hours at a pressure of 110% when the mop pipelines are not visible.

Hydrostatic (hydro-) tests are the most commonly used method for the leak testing of pipeline systems, boilers, gas cylinders, fuel tanks and other pressure vessels [2]. Hydrostatic tests are a more accurate method of testing pressure vessels than using points such as pipes or chemical cylinders for possible leaks. After construction, hydrostatic pressure tests are used for high stress (30% SMYs) and natural gas pipelines.
Hydrostatic testing is a method of testing equipment such as flammable cylinders, storage tanks, gas cylinders and chemical pipelines using hydrostatic testing equipment. Hydrostatic tests are a way for pressure vessels such as pipelines, sanitary facilities, gas cylinder boilers and fuel tanks to test the strength of leaks. Integrity assessment pressure tests are designed to determine whether a hazardous liquid or gas pipeline has sufficient strength and integrity to prevent leaks, cracks and normal operation in disturbed conditions.

The hydrotest ensures that the cylinder can withstand the necessary operating pressure to make it operational, while ensuring that it does not exhibit any leaks or other deformations that could compromise its effectiveness. The low pressure test is a water test of a high-pressure cylinder that tests whether the cylinder can withstand the required pressure and whether there are no leaks or other deformations that would release the pressure.

When testing low-pressure cylinders, it is put into a protective cage in the event it fails or explodes and connected to a water hose to measure how quickly the system is under pressure. At Koorsen, the high pressure cylinders used in CO2-SCUBA and SCBA systems are emptied before the test and filled with water so that the water temperature remains the same in the cylinder and the water jacket to ensure the same accurate readings.
Water jacket is a type of hydrostatic test in which a small pressure vessel is filled with water and deposited in a filled test chamber, the so-called test jacket. The vessel is then pressurized to measure the amount of water displaced by the water that fills the chamber and its expansion. When the vessel is pressurized and sealed, the test jacket is filled with water for a certain period of time.

The total expansion value is determined by measuring the amount of water pressed into the vessel by the test pressure and the amount of water discharged from the vessel.
This method provides the same measurements as hydrostatic tests in the water mantle (percent permanent expansion and expansion pressure), but is less accurate.

During hydrostatic testing, the pipes of the container are pressurized at normal operating pressure, which has the advantage, however, that a greater margin of confidence in the usability of the system is created.