Reference Radiographs are nondestructive testing standards universally accepted because of their high reliability in accept-reject actions.

These reference radiographs for heavy-walled steel castings are applicable to nominal section thicknesses of 4-1/2 to 12 in. ( 114 to 305 mm) and consist of two sets as follows:

• RRE028001 — (Volume I): 2-MV X Rays and Cobalt-60. This includes cobalt-60 or equivalent isotope radiation and from 2 MV up to 4 MV X Rays. Set of 28 plates 8-1/2 by 11 in. ( 216 by 279 mm) ring binder.