Maximum pipeline hydrotest pressure
Maximum pipeline hydrotest pressure
(OP)
I have a question related to the maximum hydrotest pressure for a natural gas pipeline.
API 5L X52 pipe material, 24” OD with 0.375” wall thickness will be shop hydrotested per API requirements to a hoop stress that is a minimum of 90% SMYS. This value turns out to be an internal pressure of 1462.5 psig.
When this piping is used for a natural gas pipeline, what should the maximum field hydrotest pressure be? I already know that the minimum pressure required by the design codes is 1000 psig, based on Maximum Operating Pressure.
Thanks for your help!
API 5L X52 pipe material, 24” OD with 0.375” wall thickness will be shop hydrotested per API requirements to a hoop stress that is a minimum of 90% SMYS. This value turns out to be an internal pressure of 1462.5 psig.
When this piping is used for a natural gas pipeline, what should the maximum field hydrotest pressure be? I already know that the minimum pressure required by the design codes is 1000 psig, based on Maximum Operating Pressure.
Thanks for your help!





RE: Maximum pipeline hydrotest pressure
RE: Maximum pipeline hydrotest pressure
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RE: Maximum pipeline hydrotest pressure
RE: Maximum pipeline hydrotest pressure
RE: Maximum pipeline hydrotest pressure
RE: Maximum pipeline hydrotest pressure
First the actual yield stress of the pipe is likely to be higher than the SMYS.
Second the stress is not uniform through the pipe wall.
You should be able to test to around 105% of SMYS at the lowest point of the pipeline.
The best option is a volume controlled test where the pressure is increased until the pressure change vs volume added has fallen to half of the slope evident during early pressuring. The pipe is basically pressurised until it shows clear signs of the onset of yielding.
You do need nerves of steel for this though and very good test equipment. I would strongly suggest an experienced and quality endorsed hydrotesting contractor for this.
The payoff is that you can get the maximum benefit from every mm of pipe wall put in the ground with a higher MAOP.
There are additional benefits in that the first yielding will be at locations with residual stresses from installation and welding and these will be stress relieved and left with the internal surfaces in compression.
Dennis Kirk Engineering
www.ozemail.com.au/~denniskb
RE: Maximum pipeline hydrotest pressure
as an example:
location class 1 division 2, test fluid is water, the min test pressure is 1.1 max. operating pressure and the max. is 1.1 design pressure.
Also you have to consider that the test pressure at any point of the test section shall at least be equal to the test pressure required in the B31.8 (ref. table 841.322 and A847.2), as applicable, or to the pressure creating a hoop stress of 90% SMYS of the line pipe material, based on the minimum wall thickness, whichever is higher, or unless otherwise specified by the design office.
During the hydrostatic pressure test the combined stress shall not exceed 100% SMYS of line pipe material based on minimum wall thickness. The combined stress shall be calculated in accordance with B31.8 (ref. A842.223).