Terminology

The standard US terminology for Nondestructive testing is defined in standard ASTM E-1316.[36] Some definitions may be different in European standard EN 1330.

Indication 

The response or evidence from an examination, such as a blip on the screen of an instrument. Indications are classified as true or false. False indications are those caused by factors not related to the principles of the testing method or by improper implementation of the method, like film damage in radiography, electrical interference in ultrasonic testing etc. True indications are further classified as relevant and non relevant. Relevant indications are those caused by flaws. Non relevant indications are those caused by known features of the tested object, like gaps, threads, case hardening etc.

Interpretation

Determining if an indication is of a type to be investigated. For example, in electromagnetic testing, indications from metal loss are considered flaws because they should usually be investigated, but indications due to variations in the material properties may be harmless and nonrelevant.

Flaw

A type of discontinuity that must be investigated to see if it is rejectable. For example, porosity in a weld or metal loss.

Evaluation

Determining if a flaw is rejectable. For example, is porosity in a weld larger than acceptable by code?

Defect

A flaw that is rejectable – i.e. does not meet acceptance criteria. Defects are generally removed or repaired

https://en.wikipedia.org/wiki/Nondestructive_testing#Terminology

 

Document Definitions

 

  1. Normative document: Document that provides rules, guidelines or characteristics for activities or their results.

The term normative document is a generic term that covers such documents as standards, technical specifications, codes of practice and regulations [ISO GUIDE 2].

  1. Standard: Document established by consensus and approved by a recognised body, that provides, for common and repeated use, rules, guidelines or characteristics for activities or their results, aimed at the achievement of the optimum degree of order in a given context [ISO GUIDE 2].
  2. Code of practice: Document that recommends practices or procedures for the design, manufacture, installation, maintenance or utilization of equipment, structures or products.

A code or practice may be a standard, a part of a standard or independent of a standard [ISO GUIDE 2].

  1. Specification: The document that prescribes the requirements with which the product or services has to conform.

A specification should refer to or include drawings, patterns or other relevant documents and should also indicate the means and the criteria whereby conformity can be checked [BS 4778: Part1].

  1. NDT Procedure: A written description of all essential parameters and precautions to be observed when applying an NDT technique to a specific test, following an established standard, code or specification [PCN/GEN].
  2. NDT Instruction: A written description of the precise steps to be followed in testing to an established standard, code, specification or NDT procedure [PCN/GEN].