Let’s Be Frank: Nondestructive Testing or ‘Black Magic’?

By Inspector Frank. February 25, 2021

Editor’s Note:  Writing under the pseudonym Inspector Frank, the author of this column offers a first-hand, candid view of what he has witnessed throughout his career. His purpose in sharing these experiences and opinions is to encourage readers to think deeper about what they do, why they do it, and the possible impact of their decisions.

Inspectioneering is committed to protecting the anonymity of pseudonymous authors. We do, however, hold these contributors to the same editorial standards as those writing under their own name. In this, we know the author’s identity and maintain communications regarding the author’s published works. If you have any questions, feedback, or concerns stemming from this article, please send an email to and we will forward your correspondence to the appropriate party.


So why do a lot of us think tubular inspections are acts of ‘black magic’? What about shear wave ultrasonic testing or phased array ultrasonic testing? Why do some facility owner/operators consider a lot of advanced nondestructive testing (NDT) to be a necessary evil? 

If I had a dollar for every maintenance lead who thought tubular inspection was no better than ‘rolling the bones’ in terms of providing accurate data, I would be a rich man, or at the very least, I’d be able to take everyone who reads these articles out for a nice dinner.

Has a contractor or consultant ever told you that you don’t know what you’re talking about? I don’t mean someone trying to educate you or even show why ‘Inspection Gizmo A’ is better then ‘Inspection Gizmo B’. I mean they outright told you that you have no idea what you are talking about, and that you had better let them (“the experts”) just play the wizard behind the curtain.

When you are dealing with an inspection technique that is poorly understood and a company representative that is downright combative, you get a perfect storm that can quickly lead to that particular technique losing its credibility.

Back in 2007, an owner/operator at a large refinery put a freeze on NDT tubular inspection techniques (i.e., eddy-current testing, remote field testing, near field testing, IRIS, etc.). They went back to borescope, radiography, and pulling/cutting tubes in order to ascertain the remaining life of the tubular bundle. Why? They said they had so many bad experiences with tubular testing techniques and believed they were getting no useful data out of them.

So how did things get so bad? Why did things go so wrong?

Making a Bad Situation Worse

I was once involved, as a third party, in investigating a problem with a tubular inspection company. The company had been hired to perform eddy-current testing (ECT) on a brass tube bundle that was part of an HVAC system on top of a rather large office building. The HVAC system was leaking refrigerant into the glycol/water system. They assumed the leak was in the condenser exchanger, so the inspection company tested the brass bundle (around 100 tubes, approximately 20’ long) and reported the majority of the tubes had linear through-wall indications. The bundle was rigged off the top of the office building using heavy lift helicopters and a new one was flown in and installed, at a significant cost. They fired up the new unit and found that they still had a leak. That’s when they discovered the actual issue was with some incorrectly installed seals and gaskets in another part of the system. The owner of the office building then proceeded to conduct a leak test on the old tubes and found no leaks. They also had some radiographic testing performed and found no issues with tube thickness.

This is when I got involved. Obviously, the owner of the building (or their insurers) was looking to recover some or all of the costs associated with replacing a bundle that hadn’t actually needed replacement. Upon close visual examination, we found that there were little steel wires that had been stuck to the sides of the tubes by the glycol. Turns out they had a steel mesh filter that came apart years before and some of the strands ended up in the brass exchanger. These strands gave a very strange response during the ECT. The analyst, rather than saying he had a response that didn’t match his calibration, called out “through-wall cracking.” We spent some time documenting this and writing up a report using our own ECT analysis experts. These true SMEs, because of their experience, reported that those signals should never have been called out as cracking of any sort. They stated that this anomalous reading should have been a flag for further testing and discussion with the client. If that had occured, funds would not have been needlessly spent.

The inspection company took the stance that it was unreasonable to expect the analyst to know what the signal from steel wire in a brass tube should look like. The insurance company lawyers fought against this claim. At the end of it all, the small inspection company was out of business and a bunch of decision-makers had been soured on what can be an effective NDT technique, when properly applied and understood. Instead of claiming it was unreasonable for the analyst to know what a response from carbon steel wires should look like during testing, this should (and could) have been used as a learning tool for both the inspection company and their client. Even taking this minor step could have had a drastic impact on the final outcome.

There were multiple issues that brought about this particular problem:

  1. The owner of the building had a mechanical HVAC engineer on contract. He had no prior experience with testing HVAC systems or NDT in general. If someone would have considered doing pressure/leak testing on isolated segments of the circuit, they would have found out where the leaks were occurring without needing any advanced NDT, and only had to do a minor seal replacement.

  2. No one, including the contract NDT tubular inspection company, had any understanding of what the actual potential for damage of the brass tubes in this service was. The reality was that, unless someone had introduced something new and exciting into the HVAC unit, there was nothing in the system that would cause corrosion degradation or cracking of the brass tubes.

  3. Because no one on the client side fully-understood the NDT they were doing or the potential damage mechanisms, no one questioned the ‘through-wall cracking’ assessment.

  4. The tubular analyst, when confronted with a signal that didn’t conform to expectations, called it out as cracking with no follow-up and made no comments that the signals didn’t actually match with the reported damage mechanism. At the very least, he should have flagged this to the client.

  5. The client accepted the findings and acted on them in the quickest, most expensive way possible, mainly because of a lack of understanding of the system.

  6. When follow-up showed that the tubular inspection company had made a mistake, rather than anyone trying to learn and improve, everyone immediately entrenched themselves into preparing for a (court) battle.

Validating the NDT

Substitute any bad NDT experiences you have had into the above narrative and you will probably find similarities. And I’ll bet that unfortunate experience left you forever questioning the validity of that technique.

Forewarned is forearmed. What can you do right now to ensure that, when you are getting the NDT you need, it is being performed and analyzed correctly? Here are some things to consider:

You can’t manage what you don’t understand! 

If you are the owner/operator, ensure the person overseeing NDT has at least some familiarity with and understanding of the NDT techniques being used. They don’t need to be SMEs, but they need to know the capabilities and limitations of the given NDT technique(s) being deployed. There are plenty of introductory and more advanced NDT courses out there if you have no one in your organization that fits this bill already. 

Owner/operator employees should also observe the technician’s work and ask questions. I have found the only people that don’t like talking about their jobs are people who either don’t really know what they are doing or hate what they are doing. Either of which you need to know, as you are paying them to perform NDT on your behalf.

Test the technicians and analysts! 

Set up some tests to run the NDT technicians and analysts through so you can find out if they possess certain basic competencies before you bring them on site. If you don’t have the in-house capacity to do this, there are third parties that can run these on your behalf. ASNT NDT certifications only mean something if the issuing company has set up a good training and testing program. I worked for a company where to get your ASNT UT Level I, all you had to do was sit through a brief online course. You could get the certification without ever having turned on a UT machine or taking a thickness reading (or even calibrating the machine for that matter). At the very least ask for references and phone up some people to verify if the technician(s) can ‘walk the walk.’ 

Here is an interesting aside of information. Over a three-year period, I ran UT Level II technicians through test pieces at the facility where I worked. This was done before they would be approved to do in-service shear wave flaw detection. The tests were not meant to be tricky, but were instead very straightforward. Out of about 50 technicians tested in that time frame, there were 12 who couldn’t write a report (on a given template) that documented flaw locations and sizes that were usable. There were another 5 who couldn’t set-up and calibrate the UT machine properly for the specific test parameters. These were all Level II certified technicians with at least five years experience. This was a very concerning revelation to say the least.

Work on an open and honest relationship with the NDT company. 

Problems will always occur and people will always make mistakes. This is for certain. So how should the NDT company and the owner/operator deal with these things when they happen? Does the NDT company blame others for the technical mistakes, or do they work with their clients to overcome these inevitable issues? Will they deflect and say the problem is that their owner/operator client just didn’t understand the technique or maybe called out the wrong technique for the job, or will they work with their client to improve and collaborate on selecting the best inspection technique(s) for accomplishing the desired result? Are owner/operators taking the time to learn and understand why that technician and that technique had problems on that piece of equipment, or are they simply calling the NDT company/technician incompetent and running them offsite? 

By working together to learn and better-understand the issues that have led to ‘bad data’ being used for making decisions, we can build more useful and productive working relationships. Or conversely, you can just continue to run ‘those incompetent fools’ offsite. I believe we would all be much better off if when a competent technician runs into a problem, that problem is openly discussed, analyzed, and collectively solved. These moments present an opportunity for everyone involved to learn and grow into better technicians, managers, and organizations.

Make sure you understand the systems you are inspecting! 

As an owner/operator or as an NDT technician/analyst, try to gain an understanding of the systems you are inspecting and the potential damage mechanisms in those systems. If you think you have through-wall cracking in exchanger tubes, but through-wall cracking is not a reasonable damage mechanism in that process/material situation, then it should probably be further investigated. Knowledge is power! More importantly, knowledge saves everyone from repeating avoidable mistakes.


As a final note, I would say that there are a lot of people in the inspection/NDT industry that take bad customer relations to whole new levels. Combine this with a poor understanding of NDT techniques and applications on the owner/operator side, and you have the perfect recipe for having entire NDT processes blacklisted. Oftentimes, this is because of inadequate or misunderstood results and a failure to properly evaluate what went wrong. 

Just remember, the only things we consider magic are the things we don’t understand.

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Comments and Discussion

Posted by Dana Baham on February 25, 2021
Frank, the incompetence's of NDE technicians that... Log in or register to read the rest of this comment.

(Inspectioneering) Posted by Inspector Frank on March 4, 2021
Totally agree. Other countries (i.e. Canada's... Log in or register to read the rest of this comment.

Posted by Don MacIsaac on March 15, 2021
Agree with the above. Here in Australia, I will... Log in or register to read the rest of this comment.

Posted by Rajaram Chidambaram on April 17, 2021
Frank, thanks for your article which touched on... Log in or register to read the rest of this comment.

Posted by Scott Ostland on April 19, 2021
Confirmation bias. The building management and... Log in or register to read the rest of this comment.

Posted by Andy Gysbers on April 20, 2021
Good job Frank. A few further issues to raise.... Log in or register to read the rest of this comment.

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