Ultrasonic Weld Testing vs. Radiographic Weld Testing
Ultrasonic Weld Testing vs. Radiographic Weld Testing
(OP)
Hey guys, I question came up were I work today that I would like to try and get some better information on.
Here is the issue, a spec for a project we are working on requires Ultrasonic Testing of all pipe welds being performed in accordance with B31.9 Building Services Piping. The systems are basic chilled water, condenser water, hot water, etc... All pipe is ERW carbon steel.
My questions are as follows;
1) I had always thought that an Ultrasonic Test was the best method of performing NDE on a welded joint. It shows the defects to the operator the best. However, since there is no film produced, it is up to the operator to determine the pass or fail. Here in NYC everyone likes to have an Xray done because it gets you a film that can be reviewed by anyone.
Can you guys provide me with any other reasons to perform a UT test vs an RT test and what are advantages and dis-advantages of both?
2) Granted that B31.9 Building Services piping is very lienient as far as NDT requirements are concerned (it actually doesnt require it at all but has a suggested minimum quality level,) However since all welds are to be UT tested to B31.9 standards, I still feel there is a considerable difference between a weld that will not be tested and the minimum quality level of B31.9.
What do you guys think of this? This is a major project with as many as 10,000 welds being performed for the entire building, so this could become a cost issue for us.
Please provide any insight on quality levels for welding to B31.9.
If you need further information or clarification please let me know and thanks in advance for any help.
Rob
Here is the issue, a spec for a project we are working on requires Ultrasonic Testing of all pipe welds being performed in accordance with B31.9 Building Services Piping. The systems are basic chilled water, condenser water, hot water, etc... All pipe is ERW carbon steel.
My questions are as follows;
1) I had always thought that an Ultrasonic Test was the best method of performing NDE on a welded joint. It shows the defects to the operator the best. However, since there is no film produced, it is up to the operator to determine the pass or fail. Here in NYC everyone likes to have an Xray done because it gets you a film that can be reviewed by anyone.
Can you guys provide me with any other reasons to perform a UT test vs an RT test and what are advantages and dis-advantages of both?
2) Granted that B31.9 Building Services piping is very lienient as far as NDT requirements are concerned (it actually doesnt require it at all but has a suggested minimum quality level,) However since all welds are to be UT tested to B31.9 standards, I still feel there is a considerable difference between a weld that will not be tested and the minimum quality level of B31.9.
What do you guys think of this? This is a major project with as many as 10,000 welds being performed for the entire building, so this could become a cost issue for us.
Please provide any insight on quality levels for welding to B31.9.
If you need further information or clarification please let me know and thanks in advance for any help.
Rob





RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
Actually it is usually a full body UT, not only weld sealm.
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
RT , UT, PT, EMI, have different strengths and weaknesses. I prefer RT of field welds; It is not nearly as sensitive to "artifact" orientation as is UT.Of course there are many books on the subject.
Being a cremudgeon, I suspect the objective is to have a certification in a file that the welds are good.
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
Blacksmith, what do you mean when you say Artifact orientation? I agree with you on RT of field welds. I think that is the best way to go. Also then, what would be the strengths of a UT vs. an RT?
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
UT can be just as bad. For it you need references, sample joints with known artificial defects in them. Sloppy welds can swamp the defect signal.
It would be tough to see imposing a signal to noise ratio requirement on field welds in steel.
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Plymouth Tube
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
At this point I think examination (RT) of a % of each weldors work is what can be done.
Weld quality generally increases significantly if the weldor knows there will be NDE (even if no NDE is done).
Old guy story: Contractor says the owner cannot do NDE after the job is done because there was no prior notification, (ie. if they knew there was NDE, they would have done a better job).
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
Further, RT can be done on small diameter pipes in a single shot, but requires multiple exposures for larger diameters.
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
Most are now using this method during construction for baseline inspections and compare it to future in-service inspections.
RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing
Hg
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RE: Ultrasonic Weld Testing vs. Radiographic Weld Testing