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.
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 Code sets forth engineering requirements deemed necessary for the safe design and construction of pressure piping. To the greatest possible extent, Code requirements for design are stated in terms of basic design principles and formulas. These are supplemented as necessary with specific requirements to ensure uniform application of principles and to guide selection and application of piping elements. The Code prohibits designs and practices known to be unsafe and contains warnings where caution, but not prohibition, is warranted.
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
![[cannon]](/data/assets/smilies/cannon.gif "[cannon] [cannon]")
