Forum Technical Discussions      Re: Aggressive Radiographic Auditors Need to Take a Closer Look! Posted by: Michel Couture (PID_2805), E-mail: Address, on January 04, 2009 at 18:08 : In Reply to: Re: Aggressive Radiographic Auditors Need to Take a Closer Look! posted by : Ed Ginzel    , E-mail: Address, on January 04, 2009 at 16:22 : Hi Everyone, I totally agree with all the comments that have been made so far on this topic, yet I must say that some ''agressive auditors'' do have a mind set no matter what. I'm experiencing this situation with a third party customer regarding our UT inspection. Sometimes, we discover some small flaws in the forging that are acceptable to code and that will be removed during final machining, yet the auditor will request that the forging be repaired prior to leaving the plant. This in my opinion is totally unacessary and increses the cost of manufacturing. I always said that there are two kind of people in the world. Those who makes mistakes because they don't know and those who knows but are too stubborn to change. You can educate the first one and solve your problem, the latter you should get rid of. Cheerio's Michel ----------- Start Original Message ----------- : Hi all…just a word about my comment on ‘aggressive’ auditors. After university my humble start in NDT 35 years ago was as a “radiographer’s helper” under a feisty Ulsterman who taught me this method of discriminating flaw from illusion. 18 years later he hired me as an auditor on pipeline construction and made sure I instructed radiographers on his pipelines about the technique. Over the years the pipeline owner had experienced failures that resulted at through-wall repairs (typically delayed cracking). When the original film was reviewed it was seen that this illusion was often the rationale for the repair. : However, this “instructional” function of the auditor that I was given is not a common practice around the world. It is because of the authority that the “auditor” has as the company representative that his judgement can over-rule that of an experienced radiographer. If there is no reference in a Code or Standard that provides guidance on this aspect of interpretation then the most conservative evaluation will be imposed (even if it is an illusion). Codes often have instructional phrases inserted in them so I thought that perhaps those forum members on radiographic committees might be able to submit a recommendation for revision to include a small phrase to address the potential for optical illusions being called as false rejects. : Ed : : Excellent! But usually it all comes down to experience, a sound knowledge of the welding process and a good 20/20 vision. I still see a lot of interpreters who would disregard other discontinuities or call them something else not because it was some sort of optical illusion. : : In my experience the usual cause of excessive repairs was not because of optical illusions but because of the Interpreters' lack of experience and bad vision. : : : : : : : : This is an excellent post by Ed and points up the importance of mentoring and experience in radiographic interpretation. The question of optical illusions was not raised when I first studied RT some thirty years ago and it was something I had to work out for myself. I too must report, like William, falling into the same trap. : : : I don't know that administrative action is the most effective here; maybe an article for Materials Evaluation is in order? And certainly an alert to training schools. : : : Nick : : : : Wow, one of the most interesting posts I have seen here in a while. I have some experience with this and have made the mistake myself (the call, not the bullying!). Thanks for the tip on how to possibly prevent this mistake and I look forward to seeing other comments. : : : : : I wonder if there have been others with experiences of radiographic auditors bullying their opinions of so-called lack of fusion or undercut on films where most radiographers see none? The origins of “perceived” lines of so-called undercut can be attributed to a well known optical illusion known by its illustrative image the “Herman Grid”. Here a series of black squares is separated by straight white lines and the observer perceives gray blobs in the intersections of the white crosses formed by the black squares. A similar perception is had when the black squares are made smaller and the viewer perceives faint diagonal lines in the “Springer” illusion (see http://www.sapdesignguild.org/resources/optical_illusions/contrast_phenomena.html) : : : : : Apparent brightness of a stimulus depends not only on its own luminance but also on that of the surrounding stimulation. The effect of perceiving a contrast where none exists has been documented since 1828 (Eugene Chevreul) and is generally called simultaneous contrast. : : : : : This effect has probably be responsible for more than its fair share of unnecessary repairs due to aggressive radiographic auditors calling the fine line that they “perceive” at the boundary between the pipe wall and the weld reinforcement (cap and root). : : : : : The verification that it is an illusion is easily seen by covering the “whiter” region (with a piece of dark paper) to reduce the contrast at the boundary. The faint grey line disappears, thereby verifying it to be an illusion and not a real flaw. : : : : : Yet failure to recognise this or to use this simple test, results in countless unfounded weld repairs around the world. Perhaps this issue could be (should be?) addressed in the radiographic codes and standards now used. : : : : : Ed ------------ End Original Message ------------ Follow Ups: Post a Followup: Name: E-Mail: Subject: Comments: ----------- Start Original Message ----------- : Hi Everyone, : I totally agree with all the comments that have been made so far on this topic, yet I must say that some ''agressive auditors'' do have a mind set no matter what. I'm experiencing this situation with a third party customer regarding our UT inspection. Sometimes, we discover some small flaws in the forging that are acceptable to code and that will be removed during final machining, yet the auditor will request that the forging be repaired prior to leaving the plant. This in my opinion is totally unacessary and increses the cost of manufacturing. : I always said that there are two kind of people in the world. Those who makes mistakes because they don't know and those who knows but are too stubborn to change. You can educate the first one and solve your problem, the latter you should get rid of. : Cheerio's : Michel : : Hi all…just a word about my comment on ‘aggressive’ auditors. After university my humble start in NDT 35 years ago was as a “radiographer’s helper” under a feisty Ulsterman who taught me this method of discriminating flaw from illusion. 18 years later he hired me as an auditor on pipeline construction and made sure I instructed radiographers on his pipelines about the technique. Over the years the pipeline owner had experienced failures that resulted at through-wall repairs (typically delayed cracking). When the original film was reviewed it was seen that this illusion was often the rationale for the repair. : : However, this “instructional” function of the auditor that I was given is not a common practice around the world. It is because of the authority that the “auditor” has as the company representative that his judgement can over-rule that of an experienced radiographer. If there is no reference in a Code or Standard that provides guidance on this aspect of interpretation then the most conservative evaluation will be imposed (even if it is an illusion). Codes often have instructional phrases inserted in them so I thought that perhaps those forum members on radiographic committees might be able to submit a recommendation for revision to include a small phrase to address the potential for optical illusions being called as false rejects. : : Ed : : : Excellent! But usually it all comes down to experience, a sound knowledge of the welding process and a good 20/20 vision. I still see a lot of interpreters who would disregard other discontinuities or call them something else not because it was some sort of optical illusion. : : : In my experience the usual cause of excessive repairs was not because of optical illusions but because of the Interpreters' lack of experience and bad vision. : : : : : : : : : : : This is an excellent post by Ed and points up the importance of mentoring and experience in radiographic interpretation. The question of optical illusions was not raised when I first studied RT some thirty years ago and it was something I had to work out for myself. I too must report, like William, falling into the same trap. : : : : I don't know that administrative action is the most effective here; maybe an article for Materials Evaluation is in order? And certainly an alert to training schools. : : : : Nick : : : : : Wow, one of the most interesting posts I have seen here in a while. I have some experience with this and have made the mistake myself (the call, not the bullying!). Thanks for the tip on how to possibly prevent this mistake and I look forward to seeing other comments. : : : : : : I wonder if there have been others with experiences of radiographic auditors bullying their opinions of so-called lack of fusion or undercut on films where most radiographers see none? The origins of “perceived” lines of so-called undercut can be attributed to a well known optical illusion known by its illustrative image the “Herman Grid”. Here a series of black squares is separated by straight white lines and the observer perceives gray blobs in the intersections of the white crosses formed by the black squares. A similar perception is had when the black squares are made smaller and the viewer perceives faint diagonal lines in the “Springer” illusion (see http://www.sapdesignguild.org/resources/optical_illusions/contrast_phenomena.html) : : : : : : Apparent brightness of a stimulus depends not only on its own luminance but also on that of the surrounding stimulation. The effect of perceiving a contrast where none exists has been documented since 1828 (Eugene Chevreul) and is generally called simultaneous contrast. : : : : : : This effect has probably be responsible for more than its fair share of unnecessary repairs due to aggressive radiographic auditors calling the fine line that they “perceive” at the boundary between the pipe wall and the weld reinforcement (cap and root). : : : : : : The verification that it is an illusion is easily seen by covering the “whiter” region (with a piece of dark paper) to reduce the contrast at the boundary. The faint grey line disappears, thereby verifying it to be an illusion and not a real flaw. : : : : : : Yet failure to recognise this or to use this simple test, results in countless unfounded weld repairs around the world. Perhaps this issue could be (should be?) addressed in the radiographic codes and standards now used. : : : : : : Ed ------------ End Original Message ------------ Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP Page Title: is important! Optional Image URL: http://www....gif Attention! Please click the button only once. This may take a moment to process Forum Technical Discussions Help