Abstract: A system for determining pipe wall thickness includes a supporting framework removably attachable to the outer surface of a pipe or pipe covering and supportive of an x-ray film holder. The holder and an x-radiation source are disposed on opposite sides of the pipe in a first plane which includes the axis of the pipe. The source may be moved along the axial plane to make successive exposures of the pipe on a single piece of film. Each image includes both the upper-and lower side walls of the pipe. The film holder may be radially indexed to the pipe on the supporting framework so that the film holder and source may be disposed successively in a plurality of other axial planes radially displaced from the first axial plane. For each plane, a fresh piece of film is installed in the holder.