Before specifying the use of NDT in any program, several things should be considered. First, determine exactly why, or if, NDT is required. There are many reasons why NDT may be desired or necessary: to increase the production rate (by assuring a higher success rate), to increase reliability,to improve or maintain safety, to meet legal requirements, to differentiate or identify improved processing methods, or to detect changes in the product before they become a problem. There is a danger that specifying NDT has become routine practice rather than the result of a real need: i.e., it was done this way last time: it is always done this way; they did it, we have to do it; everyone else is doing it; or let’s do it just to be safe. Sometimes NDT is specified just for administrative reasons: the contract requires it. Often, although the use of NDT is specified to satisfy a legitimate requirement, it may actually be inappropriate. For example, the ultimate purpose of a test may be to ensure that a part has its required designed strength.
Replaced/Superseded by document(s)
Although this handbook is provided as a guide to all those employed in nondestructive testing (NDT), it will be of specific interest to administrators, designers, production engineers, quality assurance personnel, and nondestructive test engineers and technicians. It has been formulated to cover both broad and specific applications of NDT, so as to satisfy individuality, as well as conformity, of interests and knowledge among the divisions of responsibility in NDT. Not everyone will be interested in all of the specially identified sections. However, to obtain optimum benefits, it is recommended that users of this document review it in its entirety, while paying particular attention to those section,often identified by a heading or subnote, which may be of specific concern to them.
The handbook, which currently incorporates general principles and procedures (as well as safety items) of eddy current, liquid penetrant, magnetic particle, radiographic and ultrasonic testing, will be updated, to include chapters on other NDT methods as they become appropriate.