A hydrostatic test is a widely used pressure testing method used to verify the integrity, strength, and leak-tightness of pressure vessels, pipelines, boilers, air receiver tanks, and other pressurized equipment.
The test involves filling the equipment completely with water and pressurizing it to a specified test pressure to ensure it can safely withstand working conditions.
Detect leaks, cracks, or weld defects
Confirm the equipment can withstand design or test pressure
Ensure the equipment meets safety regulations and industry standards
Fulfill inspection and certification requirements from authorities like DOSH / JKKP
Hydrostatic testing is commonly performed on:
Air receiver tanks
Boilers and water heaters
Pressure piping systems
Chemical or oil storage tanks
Fire suppression piping systems
Isolate the equipment and ensure it’s depressurized and cleaned
Fill the equipment with clean water, removing all trapped air
Use a manual or electric pump to pressurize the system to the required test pressure (usually 1.3–1.5 × working pressure)
Hold the pressure for a set time (typically 10–30 minutes), and monitor for pressure drop, leakage, or deformation
Record the results. If there’s no leakage or visible defect, the equipment passes the test
Tests must be performed by qualified personnel
Pressure should be increased gradually
Establish a safety perimeter and restrict access during the test
If any leaks or abnormalities occur, stop the test immediately
After testing, drain and dry the equipment properly
Under the Factories and Machinery Act 1967 and DOSH / JKKP regulations in Malaysia:
Air receiver tanks and pressure vessels must undergo periodic hydrostatic testing
Typically required every 15 years, or based on equipment condition and regulation
Tests must be performed by DOSH-approved competent parties or third-party inspectors
Test reports must be documented and submitted to DOSH for record-keeping
| Item | Hydrostatic Test | Pneumatic Test |
|---|---|---|
| Test Medium | Water | Air or Nitrogen |
| Risk Level | Lower (water is non-compressible) | Higher (compressed gas is explosive) |
| Common Use | Standard, routine pressure tests | For small leaks or sensitive systems |
| Safety | Safer | Riskier |
Ensure pressure equipment operates safely
Detect hidden faults early
Comply with legal and industry standards
Whether for pre-commissioning checks or scheduled maintenance, hydrostatic testing plays a vital role in protecting both equipment and personnel.
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