Low pressure closure test
Low pressure closure test
(OP)
What is the main purpose of low pressure closure test in API598.according to mentioned standard there are also high pressure closure test which is done by higher pressure.
so when we use it?
and what is the advantage of that?
so when we use it?
and what is the advantage of that?





RE: Low pressure closure test
Another important thing to note is that the low pressure closure and low pressure back seat tests can only be performed with air or gas, whereas the high pressure test can be performed with liquids.
Even if the test is listed as optional in the Tables 1-A or 1-B, the valve is still required to be ABLE to pass the test as described.
The reason there is a high pressure and low pressure sealing test is because some valve styles and seating styles will seal better at higher pressures (harder seating materials typically) and not so great at low pressures, and vice-verse. This specification ensures that the design is capable of sealing to the required extent at a wide range of pressures.
RE: Low pressure closure test
Also consider that in these types of valves with plastic seats, testing at the maximum pressure applies higher forces of the plastic sealing parts and can cause them to deform more than they would when they are installed and running at lower pressures. More deformation can shorten the operational life of the plastic sealing elements.
Keep in mind that the factory tests are intended to be checks of the production quality and should be selected to be the most discerningand minimize the impact to the future operational life. In such plastic seated valves, the ability to seal at maximum pressure is a design validation that should be done indepedent of the factory tests to prove the design is appropriate.
RE: Low pressure closure test