NDT (radiography) and Hydrotesting
NDT (radiography) and Hydrotesting
(OP)
Hi All,
In order to comply with B31.3, do I need to carry out both hydrostatic testing and NDT (radiography) for a pressure piping system (say instrument air piping) or can I eliminate NDT and carry out hydrostatic testing only?
please help
Thanks
In order to comply with B31.3, do I need to carry out both hydrostatic testing and NDT (radiography) for a pressure piping system (say instrument air piping) or can I eliminate NDT and carry out hydrostatic testing only?
please help
Thanks





RE: NDT (radiography) and Hydrotesting
Hydrotest is for making sure there is no leak in the system. And at the same time you may have welds with problems and they don't show up during the hydrotest.
Usually up to 10% random X-Ray is a common practice for making sure the welds have been performed properly (acceptable quality).
On a different note:
B31.3 is a code and not a design guide. It won't dictate all the tests that you MUST perform for a specific service.
It is up to the design body to make sure the design is safe.
Usually the piping class for the service in this case Instrument Air contains the required tests, or company specific piping installation specification may list the tests required.
Hope this helps.
Frank
Saipem
RE: NDT (radiography) and Hydrotesting
RE: NDT (radiography) and Hydrotesting
RE: NDT (radiography) and Hydrotesting
Would you please specify which part of B31.3 is talking about this?
I searched all over the 2010 edition and was not able to find it.
I really appreciate your feedback.
Thanks,
Frank
RE: NDT (radiography) and Hydrotesting
So tell you what, send me your current copy and I will look it over and if it is still there I yellow high-lite it and send it back to you.
Let me know and I will send you my address.
RE: NDT (radiography) and Hydrotesting
RE: NDT (radiography) and Hydrotesting
You are absolutely right and it is still called for Category D fluid service.
My apology.
The reason I followed up with you on this subject is I can see in if not all but most of the companies they use the same rules as applied to process lines to Cat. D lines as well.
Thanks again,
Frank
RE: NDT (radiography) and Hydrotesting
As much as possible, do it right the first time...
RE: NDT (radiography) and Hydrotesting
I cannot even begin to imagine that some major or minor Refiner/Energy Company would consider such hair brained idea.
I cannot imagine any responsible Instrument manufacturer would allow hydrocarbon gas to be used in their instruments.
I also do not think it would pass the HAZOP Review.
RE: NDT (radiography) and Hydrotesting
I agree I wouldn't want to see it used in a Refinery or significant sized processing plant.
RE: NDT (radiography) and Hydrotesting
The instrument air design pressure (1320kPag) in this case exceeds Category D therefore this piping system belongs to Normal Fluid hence require hydrotest. It is now clear that 5% RT (min) is also required.
RE: NDT (radiography) and Hydrotesting
I cannot even begin to imagine that some major or minor Refiner/Energy Company would consider such hair brained idea.
I cannot imagine any responsible Instrument manufacturer would allow hydrocarbon gas to be used in their instruments."
Sales gas is used a lot over here in Aus to drive actuated valves/ESD's on remote sites, it's common practice as long as the actuators/instrument MOC are suitable for sales gas.
RE: NDT (radiography) and Hydrotesting
For instrument air piping systems, the code-permissible alternative to hydrotesting (the pneumatic test at 110% of design pressure) is usually pretty low risk, and not all that different than the commodity test.