Hydro-static testing
Hydro-static testing
(OP)
I have a question concerning welds in a hydro-static test. Simply do welded Temporary caps in a test section have to be fully welded and x-rayed.
I need to know if there is a code that states this one way or another. I have looked thru CFR 49- 192 & 195 ASME Section 9 and cannot find any thing. and before you bring up the obivious. I am working with a fab shop and refinery that are questioning my requirement that ALL welds in the test sections have to be full, complete and Xrayed. Their normal practice is to put in a bead and hotpass for all Temp. welds in a hydrotest section. FYI test pressure is 1875psi for 4 hrs.
I need to know if there is a code that states this one way or another. I have looked thru CFR 49- 192 & 195 ASME Section 9 and cannot find any thing. and before you bring up the obivious. I am working with a fab shop and refinery that are questioning my requirement that ALL welds in the test sections have to be full, complete and Xrayed. Their normal practice is to put in a bead and hotpass for all Temp. welds in a hydrotest section. FYI test pressure is 1875psi for 4 hrs.





RE: Hydro-static testing
You wrote, "I am working with a fab shop and refinery". This suggests you should be looking at ASME B31.3.
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It has been a while since I have looked but I think B31.3 only requires a small percentage of the joints to be Xrayed, not 100 percent Xray.
I also think B31.3 does not require Xray of temperature test closer welds. You are just going to cut them off after hydrotest to make the final Installation welds. Those final installation Welds do need to be Xrayed.
Sometimes its possible to do all the right things and still get bad results
RE: Hydro-static testing
RE: Hydro-static testing
Neither the cap nor the weld know that it is "temporary", hence there is no reason why this weld, compared to the one next door to it is treated ANY DIFFERENTLY.
The reason you won't find this quite frankly sloppy and dangerous practice in the code is is because it is sloppy and dangerous. The shop may well have been getting away with it for years, but that doesn't make it right.
Simply tell the shop that a weld is a weld is a weld and treat them all the same. There is no reduction specified in any design code I've ever seen so the absence of something means it is not covered. Codes don't like telling you things you can't do because if they miss one off the list then they are in trouble. They tell you things you can do or should do. Thus your comment "I have looked thru CFR 49- 192 & 195 ASME Section 9 and cannot find any thing" is correct. Therefore their practice is NOT ALLOWED.
Sorry for shouting, but this really annoys me and poor practice in testing leads to accidents, injuries and death. Those small caps can shoot off faster than a bullet...
Rant over. Stick to your guns.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydro-static testing
https://www.osha.gov/pls/imis/accidentsearch.accid...
https://www.cdc.gov/niosh/face/stateface/ok/99ok01...
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydro-static testing
General statement, not arguing this is acceptable.....Good engineering judgement must be used....
RE: Hydro-static testing
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydro-static testing
RE: Hydro-static testing
RE: Hydro-static testing
Without laboring the point "You can still be code compliant if you do something that the code doesn't specifically state you are allowed to do. " - I disagree.
when you look at the words you quote it simply means it is not prohibited, but then you're on your own. It may very well be justifiable and be acceptable, but it is not IMHO, "code compliant".
Anyway I think we've got the main jist out there and I hope John manages to get them to do it properly. The biggest danger for a hydrotest is actually the small caps / nozzles as they can get a big velocity before the pressure in the pipe falls very rapidly. Big ends just tend to fall off and crush your foot....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydro-static testing
I have to agree with David. "Engineering Judgement" plays its most important role. The code only requires the minimums of all things needed, as there are theoretically an infinite number of additional requirements which may be necessary at times to provide a safe design for any given specific system. Rather than attept to create a code addressing an infinite list of cases and covering an infinite^2 list of requirements for of all of them, the code provides only the collective minimum requirements for any system within its scope and defining all remaining requirements for any specific system at hand is left up to the responsible engineer.
For example B31.8
The way I learned to read that is ... Codes, or the CFRs, tell you ONLY the MINIMUM of what you MUST do. You (as the responsible engineer) are perfectly free to do anything that is not mentioned in the code, as long as (presumably) you consider it necessary to meet the intent of the code, which is pretty much simply put only to provide a safe, useable and workable design. (That might even include drilling a hole in the pipe wall, or through the disk of a check valve, if you think you need to, although you won't find either of those in the codes). In fact you are REQUIRED TO DO MORE than the code requires, each and every time that you, as the responsible engineer, believes it is necessary to result in a safe and workable design.
What you must do all the time is at least what the code, or CFRs say you must do. You only have to follow their recommendations when you, as the responsible design engineer, agrees. What you must not do is anything the code says you cannot do. What you can do is ANYTHING else that you as the responsible engineer considers necesary to meet the intent of the code (ie. whatever results in a safe and workable design). What you also MUST DO is anything else you think is necessary to get to that point.
Getting back to the OP question, which appears to be in regard to "temporary" pieces of pipe and fittings that are only neeed for testing purposes and will be removed after testing is completed. There is not and answer to be found in these design codes. These design codes do not address the requirements for non-permanent portions of piping systems. We have prevoiusly discussed this topic in this forum and failed to come to a uniform agreement. Some of us considered that these temporary components should be designed exactly as permanent components, using the "test pressure" as their "design pressure". Others, of whom I was not one, considered that the temporary test components could be stressed to 100% of yield anytime they were being used. I wouldn't want to ride Chuck Yeager's Bell X-1 test airplane, if it was designed to like be at 90% yield crossing the sound barrier. Ha ha ha ha. I'd say ... At least complete the welds ... the X-ray question is up to whoever survives the test.
If a (the, any) un-hydrotested weld remains within the permanent pipe and components of a pipeline after testing and repair under B31.4 or 31.8 codes, the weld(s) must be X-rayed. Thus pipe assemblies made for repairs are pretested, temporary end caps, or other non-permanent fittings and headers, etc. are cut off and removed, then the remaining assembly is dropped in and welded into the original pipe. Those "golden" welds have not been hydrotested, so they must be X-rayed. There are (usually) only two such golden welds allowed for any given repair, one on each side of the pre-tested assembly. The pipeline codes specifically prohibit making a longer pipeline by joining pretested pipes or assemblies together by the use of un-hydrotested, X-rayed, "golden" welds.
Reaction to change doesn't stop it