Gauging plates are aluminum plates sized close to the pipeline’s internal diameter. They indicate out-of-specification pipeline geometry through impact marks or dents. They are used to help verify pipeline installation and determine whether larger or more demanding pigs, such as inspection or smart pigs, can pass safely. Plate outside diameters range from 90% to 95% of the pipe’s internal diameter, and slots can be cut into the perimeter for easier deformation identification. Depending on the size of the pig, plates can be 1/8 in, 1/4 in, 3/8 in or 1/2 in thick. The standard material is aluminum, but steel can also be used.