Back to Basics
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What is Basics?
by Frank A. Iddings*
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I get questions. Mostly, they boil down to "what is basic?" What I have tried to do this month is give my answer to that question in the form of a short article. This is certainly not a standard or a law carved into stone, but it may be something that will help you develop your own answer to the question. Frank Iddings Tutorial Projects Editor |
Introduction
What are the basics for nondestructive testing (NDT)? The number of different answers would probably equal the number of people answering and they could all be correct in terms of how the individual was involved in NDT. Certainly the basics include the physical laws that are involved, the fundamentals of each method and the rules of thumb that we follow because they work. In addition, there are the properties of the materials being tested, a knowledge of the fabrication techniques involved, the influence of a discontinuity that causes it to become classifiable as a flaw, how well the selected technique works and so on and so forth.Do the basics include everything? No, but there are a lot of things that are basic. Does it seem there are more things that are basic than there used to be? Yes, I think so. That is because there are more complicated problems to solve, more difficult materials to test and more demanding criteria to be met. The world has changed and in many respects it has not gotten easier to do NDT. However, we do have better equipment and some new and more sophisticated methods (and, hence, more and different basics to master!). To have the improved inspectors to go with the new methods, we must have inspectors who are really good with the basics as well as all of the details that go into doing a job well.
Definition and Synonyms
So what are the basics (at least as I see them)? Let's start with a definition and the synonyms for "the basics." My working definition - developed during my 40 years in this field - is that the basics are the necessary information that allows you to understand how a technique works, permits you to perform the inspection and gives you the ability to evaluate the useful integrity of the specimen. Of course, there are also a lot of details that are not basic that come into play as well. To me, however, omitting a basic results in fatally flawed NDT.
To me, something is basic if you need to know it to do the job correctly, reliably and safely.
Looking at some of the synonyms of the word "basic" should help us better understand what the basics are in NDT. These synonyms include such words as "crucial," "fundamental," "important," "indispensable," "major," "necessary" and "vital." When we satisfy these words, we satisfy the basics. Substitute these words when you think of basics and you will begin to feel about the basics of NDT as I do.
Knowledge
Knowing that there are basics is not enough. You must know the basics and have enough experience applying them that they become second nature to you. That is asking you to know a lot. There are the fundamentals of the technique, properties of the materials, fabrication effects on the materials, service use effects, differences between discontinuities and flaws (as well as knowing when an indication is one or the other) and knowing how reliable your information is. This means asking you to know about probability of detection for the procedure you are doing in appropriate circumstances. Something new has been added to our basics, again. You also must know when you need to know these things. Knowing how to do some NDT is not enough. You must know if it is properly done to answer the question: "Is this specimen satisfactory to perform its designed task for the time required?" That used to be an easier question to answer. The basics needed were simpler, too.Knowledge of how to do the job safely is also basic. The theme of an early "Back to Basics" column was that nondestructive testing should not only be nondestructive to the material or component being tested, but be nondestructive to the inspector and to the public as well. As I wrote at the time, "safety is just as basic to the nondestructive test as are good results and good interpretations. Certainly safety without results and interpretation is worthless but the reverse is equally true" (Iddings, 1979). While a lot has changed since I wrote this in 1979, this remains true today.
Conclusion
Does it begin to sound like basics are all inclusive? Some things, like the fundamentals of a technique, always are. Some things may or may not be depending upon the circumstances. Other things never are. Who signs your time sheet is important but not basic. Leaving out something basic would be the same as cutting off a leg on a three legged stool. It won't work right that way.To me, something is basic if you need to know it to do the job correctly, reliably and safely. I hope that comes close to what basic means in NDT to you.
References
Iddings, Frank A., "Editorial," Materials Evaluation, Vol. 37, No. 11 (October 1979), p. 20.
* 1635 Rob Roy Lane, San Antonio, TX 78251; (210) 647-7717; e-mail <profiddings@satx.rr.com>.
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