Technical Justification 

TJ Technical Justification – a document used in Inspection Qualification (IQ – see link to the left).

A TJ is most commonly used for a collection of all the necessary information which provides evidence that the inspection system can meet its stated objective. However, a TJ may be used to justify the defects or test-pieces for use in trials, or alternatively to justify the use of an inspection which is similar to one which has already been qualified, ie to cover an equipment upgrade of a similar geometry.

Typically, a TJ follows a set format. It starts by providing a summary of all relevant input information such as the component geometry, defects to be detected and the required inspection performance. It then provides an overview of the inspection system before analysing the 'influential parameters' which affect the outcome of the inspection. Qualitative arguments for why the choice of procedure and equipment parameters will achieve the inspection requirements are presented in a section called Physical Reasoning. The use of computer modelling is then described before experimental evidence is reported. This experimental evidence can include work reported in the literature. Experimental evidence which examines the effect of a particular parameter on the inspection, such as the transmission of ultrasound through cladding or paint, is presented in a separate chapter entitled Parametric Studies. Finally, evidence to support the use of the particular hardware and software and any data analysis scheme is considered before a chapter provides a summary of all the evidence.

For more information on the use of a TJ see:
ENIQ Recommended Practice 2: Recommended Contents for a Technical Justification Issue 1
July 1998 ENIQ Report no 4 EUR 18099 EN

ENIQ Recommended Practice 3: Strategy Document for Technical Justification, Issue 1
July 1998 ENIQ Report no 5 EUR 18100 EN

Both documents can be downloaded from:

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