This guide will include post-process non-destructive testing of additive manufacturing (AM) of metallic parts with a comprehensive approach. It will cover several sectors and a similar framework can be applied to other materials (e.g. ceramics, polymers, etc.). In-process NDT and metrology standards will be referenced as they are being developed. This guide will present current standards capability to detect which of the Additive Manufacturing (AM) flaw types and which flaws require new standards, using a standard selection tool. NDT methods potential to detect AM flaws not covered by current standards will be recommended, and as new standards for flaws not covered by current standards are developed, they will be referenced in this standard via document updates. This part of the International Standard: ⎯ Categorises AM defects ⎯ A review of relevant current standards ⎯ Enables suitable current standard NDT method/s to be used; ⎯ Details method specific to additive manufacturing and complex 3D geometries; ⎯ Outlines existing non-destructive testing techniques applicable to some AM types of defects; This part of the International Standard is aimed at users and producers of additive manufacturing processes. It applies wherever additive processes are used, and to the following fields in particular: ⎯ Safety critical applications; ⎯ Assured confidence in additive manufacturing; ⎯ Reverse engineered products manufactured by additively manufactured; ⎯ Test bodies wishing to compare requested and actual geometries. NOTE Most metal inspection methods in NDT use ultrasound or X-rays, but these techniques cannot always cope with the complicated shapes typically produced by AM. In most circumstances X-ray computed tomography (CT) is a more suitable method, but it also has limitations and room for improvement or adaptation to AM, on top of being a costly method both in time and money.