Hydrostatic testing is the most common procedure used to qualify newly manufactured cylinders, spheres and tubes used for the transportation of dangerous goods. Hydrostatic testing is also required periodically to re-qualify these pressure vessels for continued service. During a hydrostatic test, a pressure vessel is placed inside a closed system, usually a test jacket filled with water, and a specified internal water pressure is applied to the container inside this closed system. The applied internal pressure causes an expansion of the container being tested, and the total and permanent expansion that the container undergoes are measured. These volumetric expansion measurements, in conjunction with an internal and external visual inspection of the container, are used to determine if a pressure vessel is safe for continued use, or has suffered from a degradation in its structural integrity and must be condemned.
Some pressure vessels may be re-qualified by means of a proof-pressure test. This method, also known as a modified hydrostatic test, consists of subjecting a pressure vessel to a specified internal pressure and inspecting the pressurized container for leaks, bulges or other defects. This method is permitted only when the applicable regulations do not require the determination of volumetric expansion measurements (e.g. for certain types of low pressure cylinders such as those used on many portable fire extinguishers).
Pressure testing services
Internal pressure test:
- Hydrostatic pressure proof, burst and leak test
- Maximum static pressure up to 30,000 psi
- Test media is water
- Impulse pressure test in any waveforms up to 10,000 psi
- Cyclic pressure test anywhere between 0 and 15,000 psi
- Data acquisition system records pressure time history and burst point