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Technical Discussions
Nick Welland
Nick Welland
07:25 Nov-07-2003
Inadvertant testing

What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?


    
 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1266

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1266
05:13 Nov-08-2003
Re: Inadvertant testing
Nick:
This is an interesting topic.
You have asked about the "prevailing attitude". Perhaps the "attitude" will vary based on several considerations. At some level this must be an ethical item. The NDT inspector that has made the discovery should not be burdened by the "restrictions" of the Code or specification for "location". I agree with your recommendation that it be reported and the position noted.

An NDT operator is not to worry about the engineering aspects so the NDT report should provide the engineer with information on which to assess service-ability. A good engineer would consider the implications if the assessment was related to fitness for service. If outside the area where flaws are critical the engineer can quickly decide.
If the finding is in a "spot check" region and a workmanship criteria is applied this COULD open the door to many more spot checks or even 100% inspection....but spot checks now enters the realm of statistics where it is probably commonplace to cheat. If a fabricator knows the "spots" to be inspected they might put their best welders on the area and sometimes even do a pre-NDT check to verify that no rejectable condition would be detected . But when it IS detected adjacent to the "spot" who is at fault? The NDT inspector that reports findings or the production supervisor that set up the non-statistical inspection condition or the engineer that ignores the NDT inspector's report?
Good question! Good topic!

----------- Start Original Message -----------
: What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
------------ End Original Message ------------




    
 
 Reply 
 
Uli Mletzko
R & D, Retired
Germany, Joined Nov 1998, 89

Uli Mletzko

R & D, Retired
Germany,
Joined Nov 1998
89
02:33 Nov-10-2003
Re: Inadvertant testing
----------- Start Original Message -----------
: What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
------------ End Original Message ------------

If, just by case, an inspector finds a flaw outside of the intended inspection area, this flaw has to be recorded and to be evaluated according to those codes, which are valid for that 'outside' area.

E.g., one has to inspect circumferental site welds of a pipeline, and he detects a flaw in the longitudinal shop weld of the pipe. This case, or similar cases, where one detects something in the base metal near the weld, are very common. And from the view points of quality, safety and NDT ethics, you can't then close your eyes. If necessary, the flaws have to be repaired or the object has to be rejected.

The argument, that the flaw can be tolerated or that the object can be accepted, because the flaw was outside of the intended inspection area or above the intended sample rate,

due to my opinion is not legitimate.

Regards
Uli Mletzko

NDT Group, Materials Testing Institute,
University of Stuttgart, Germany


    
 
 Reply 
 
David Harvey
Engineering
ATI - Wah Chang, USA, Joined Nov 2002, 42

David Harvey

Engineering
ATI - Wah Chang,
USA,
Joined Nov 2002
42
06:53 Nov-10-2003
Re: Inadvertant testing
----------- Start Original Message -----------
: : What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
: If, just by case, an inspector finds a flaw outside of the intended inspection area, this flaw has to be recorded and to be evaluated according to those codes, which are valid for that 'outside' area.
: E.g., one has to inspect circumferental site welds of a pipeline, and he detects a flaw in the longitudinal shop weld of the pipe. This case, or similar cases, where one detects something in the base metal near the weld, are very common. And from the view points of quality, safety and NDT ethics, you can't then close your eyes. If necessary, the flaws have to be repaired or the object has to be rejected.
: The argument, that the flaw can be tolerated or that the object can be accepted, because the flaw was outside of the intended inspection area or above the intended sample rate,
: due to my opinion is not legitimate.
: Regards
: Uli Mletzko
: NDT Group, Materials Testing Institute,
: University of Stuttgart, Germany
------------ End Original Message ------------

Such an indication should definitely be reported - described, located, and detailed as much as possible - but if it is outside of the required evaluation area, reporting is as far as the inspector can go. The responsible engineers must have the final word, but they must first have the detailed report from the inspector to be able to make a decision. One certainly cannot ignore possible defects just because they happened to be seen on the "wrong" side of the location marker.


    
 
 Reply 
 
Kip Mankenberg
Consultant
USA, Joined Nov 2003, 9

Kip Mankenberg

Consultant
USA,
Joined Nov 2003
9
04:29 Nov-11-2003
Re: Inadvertant testing
----------- Start Original Message -----------
: : : What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
: : If, just by case, an inspector finds a flaw outside of the intended inspection area, this flaw has to be recorded and to be evaluated according to those codes, which are valid for that 'outside' area.
: : E.g., one has to inspect circumferental site welds of a pipeline, and he detects a flaw in the longitudinal shop weld of the pipe. This case, or similar cases, where one detects something in the base metal near the weld, are very common. And from the view points of quality, safety and NDT ethics, you can't then close your eyes. If necessary, the flaws have to be repaired or the object has to be rejected.
: : The argument, that the flaw can be tolerated or that the object can be accepted, because the flaw was outside of the intended inspection area or above the intended sample rate,
: : due to my opinion is not legitimate.
: : Regards
: : Uli Mletzko
: : NDT Group, Materials Testing Institute,
: : University of Stuttgart, Germany
: Such an indication should definitely be reported - described, located, and detailed as much as possible - but if it is outside of the required evaluation area, reporting is as far as the inspector can go. The responsible engineers must have the final word, but they must first have the detailed report from the inspector to be able to make a decision. One certainly cannot ignore possible defects just because they happened to be seen on the "wrong" side of the location marker.
------------ End Original Message ------------

Most codes/specs require that the fabricator is responsible for doing work in accordance with the requirements of the code/spec. Therefore, if a defect (i.e. a discontinuity that would be rejectable based on the applicable acceptance criteria - RT for instance in your example) is noted outside of the area of interest, it is generally very easy to argue that the area or work in question does not meet the requirements of the code/spec and needs to be repaired/reworked in accordance with the requirements of the code/spec.
Mankenberg



    
 
 Reply 
 
DJ Kallhof
DJ Kallhof
03:20 Nov-11-2003
Re: Inadvertant testing
----------- Start Original Message -----------
: What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
------------ End Original Message ------------

What is found cannot be ignored, period. The discovery must be presented to the customer. The type, size and location of the indication. The emphasis is on indication. What applies to the area of interest may not apply to an area further removed from the weld and or HAZ. Without specific acceptance criteria, short of being a design engineer, the inspector is not qualified to disposition an indication accept/reject. If the customer is concerned about inadvertent findings, assure them the inspectors are using the smallest film possible, to complete the inspection.


    
 
 Reply 
 
David Davies
David Davies
08:51 Nov-12-2003
Re: Inadvertant testing
The case in question seems to be that a percentage inspection revealed discontinuities outside the code.
The percentage method is chosen so as to give a representative indication of the general quality of the whole item.
In my opinion the area marked as the area to be inspected is irrelevant once the work has been shown to include non acceptable discontinuities then further investigation needs to be made, whether going to 100% or increasing the percentage.
The quality of work has been shown to be not acceptable, as a percentage of the area actually inspected it may be large. If this assessment is applied to the whole item then the possibility exists of there being widespread defects which could seriously impair the items suitablility for purpose.
Any fabricator who tries to hide behind the "it's not in the marked area" excuse needs to be educated. If they truly care about their product they will investigate the matter and apply more testing and/or other measures to improve product quality.
Remember, a major defect just out of the film coverage may lead to a failure and severe injury or death to some innocent party. How will you feel knowing that the item was demonstrably faulty and you turned a blind eye???
Alternatively, in the pipeline example quoted, the repair cost may be thousands of dollars. What is the clean up cost of a burst??? Who is responsible for this cost?

In the subsequent investigation the films will certainly be pulled and the defect so easily ignored will be seen. Where does this leave you and your company? You can guarantee the fabricator will say that he relied on your expert advice.



    
 
 Reply 
 
Mike Trinidad
Consultant,
LMATS Pty Ltd , Australia, Joined Jan 2003, 138

Mike Trinidad

Consultant,
LMATS Pty Ltd ,
Australia,
Joined Jan 2003
138
05:57 Nov-15-2003
Re: Inadvertant testing
----------- Start Original Message -----------
: Nick:
: This is an interesting topic.
: You have asked about the "prevailing attitude". Perhaps the "attitude" will vary based on several considerations. At some level this must be an ethical item. The NDT inspector that has made the discovery should not be burdened by the "restrictions" of the Code or specification for "location". I agree with your recommendation that it be reported and the position noted.
: An NDT operator is not to worry about the engineering aspects so the NDT report should provide the engineer with information on which to assess service-ability. A good engineer would consider the implications if the assessment was related to fitness for service. If outside the area where flaws are critical the engineer can quickly decide.
: If the finding is in a "spot check" region and a workmanship criteria is applied this COULD open the door to many more spot checks or even 100% inspection....but spot checks now enters the realm of statistics where it is probably commonplace to cheat. If a fabricator knows the "spots" to be inspected they might put their best welders on the area and sometimes even do a pre-NDT check to verify that no rejectable condition would be detected . But when it IS detected adjacent to the "spot" who is at fault? The NDT inspector that reports findings or the production supervisor that set up the non-statistical inspection condition or the engineer that ignores the NDT inspector's report?
: Good question! Good topic!
: : What is the prevailing attitude to "inadvertant testing", as in RT when a defect is seen outside the length marked for inspection. My own attitude is, call it but note where it is. Some Codes are specific on the subject, but other remain silent as if this never happened. What is the concensus of the Forum?
------------ End Original Message ------------

Yes a very interesting topic. I have had an experience where a contractor doing large cross sectional welds on a chrome moly pipe normally to each other but in one location to a valve. Radiograpy found a defect in the actual valve material not the weld or the pipe. Turned into an interesting scenario as obviously the welding contractors didn't want anything to do with it.




    
 
 Reply 
 
David Harvey
Engineering
ATI - Wah Chang, USA, Joined Nov 2002, 42

David Harvey

Engineering
ATI - Wah Chang,
USA,
Joined Nov 2002
42
06:44 Nov-15-2003
Re: Inadvertant testing

: Yes a very interesting topic. I have had an experience where a contractor doing large cross sectional welds on a chrome moly pipe normally to each other but in one location to a valve. Radiograpy found a defect in the actual valve material not the weld or the pipe. Turned into an interesting scenario as obviously the welding contractors didn't want anything to do with it.
------------ End Original Message ------------

In my experience, defect indications in an adjacent weld are usually pretty easy to handle, and very difficult to argue against. Usually repair is more or less straightforward, since there are usually welders available to do the repair. But if the defect is found in base material, or as in your example a valve body that probably was bought off with RT at the manufacturer, it really can get sticky. The weld inspectors probably don't know what the acceptance criteria are for the valve body, and may not be expert in dealing with castings. Sometimes it takes a lot of research to find out just who made the part or base material, and just what those criteria are. So, back to my original statement, it is up to the inspector to report what he/she has seen and allow the Level III and Quality Engineering to deal with the design engineers to make sure all is OK.

Thinking about castings a bit, what about the casting that has a particular area that requires RT, an area which is adjacent to an area that requires no RT. Now if a "defect" is inadvertently found there, in the area that does not require RT, do we typically get concerned?




    
 
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