Pressure testing is a way to provide quality assurance/demonstration of installation and helps identify damaged or defective pipe, fittings, joints, valves, hydrants and thrust restraint systems. There are many advantages of pressure testing such as decreasing expense risks and decreasing health and safety risk.  We can divide pressure testing into 2 cases:
1. Hydrostatic Pressure Test.
2. Pneumatic Pressure Test.

Hydrostatic Pressure Test: is a way in which leaks can be found in pressure vessels, pipelines and plumbing. Using this test helps maintain safety standards and durability of a vessel over time. Newly manufactured pieces are initially qualified using the hydrostatic test, they are then continually re-qualified at regular intervals using the proof pressure test which is also called the modified hydrostatic test. Hydrostatic testing is also a way in which a gas pressure vessel, such as a gas cylinder or a boiler, is checked for leaks or flaws. Testing is very important because such containers can explode if they fail when containing compressed gas.

Pneumatic Pressure Test: This involves higher final pressure and also involves higher risk, so this method must only be used when hydrostatic testing is not practicable. No work should be carried out on the piping during the test, if the compressed air supply cannot be controlled from outside the test area then the pipe work in the test area should be protected to limit damage if an explosive failure of the piping occurs.