question about alternative test
question about alternative test
(OP)
Hi everybody,
Q1. What is combination test (in piping)? And when can we use...?
Q2. There is a large diameter process pipe (24") with 10 bar design pressure(& 15 bar hydrotest pressure). Can we test it with N2 and 15 bar pressure, instead of water?
Thanks.
Q1. What is combination test (in piping)? And when can we use...?
Q2. There is a large diameter process pipe (24") with 10 bar design pressure(& 15 bar hydrotest pressure). Can we test it with N2 and 15 bar pressure, instead of water?
Thanks.





RE: question about alternative test
Q1. A combination test is a two part test, the first part involves pneumatic testing with low pressure air (or nitrogen) for major leaks. The second part involves the standard hydrostatic test.
A low air (or nitrogen) pressure, most often 25 psig, is first used to see if there are major leaks. This low pressure reduces the danger of personal injury but still enables major leaks to be quickly located. Repairs, if needed, can then be done before the hydrostatic test. This method can be very effective in saving time, particularly if it takes a long time to fill a system with water only to find leaks on the first try. If leaks are found in a hydrostatic test, it will take longer to remove the water and dry the piping sufficiently to make repairs.
Q2. Testing to 15 Bar pressure with nitrogen is not recommended as a test with that high of a gas pressure is unsafe.
RE: question about alternative test
RE: question about alternative test
2) Yes you can, but there are a numbe rof issues to check first. This paper highlights some http://www.engineering.com/DesignerEdge/DesignerEd...
and if you search pneumatic testing on this site you find lots of others. A good risk assessment is key and protection of people and plant is required.
Normally requires special permission and you need to justify it. Cryogenic pipe is often tested this way to avoid water contamination.
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