CAN/CGSB-48.5-95 Part II: Chapter 8

8.1 Introduction The technique used to radiograph a specimen generally refers to the sum total of all procedures, equipment and accessories used to examine it. This chapter deals primarily with the geometrical considerations, i.e., the positioning and orientation of the source of radiation energy, in relation to the specimen and the film. Each arrangement is unique to the shape of the specimen in question, its size, the material or materials of which it is composed, the section of specimen to be examined, its location in relation to other features and practical difficulties associated with obtaining a set-up that will provide an acceptable examination. There are certain techniques or arrangements that can be considered fundamental to the geometry and size of the part regardless of its fabrication process or its end use. In this case we need not be concerned whether the specimen is, for example, a weld or a casting or an electrical component or a structure such as a nuclear plant. We need only to be concerned that the technique used complies with the standards or specifications relating to the end product. In some cases the geometry of the part may be peculiar to a specific component or structure. The radiographic technique must then be compatible with the product, and its end use.