Can pigs miss defects?
All pigs are designed against a target inspection performance. The first step in the inspection process is to develop an inspection specification which, if achieved, means that no defect that could lead to pipeline failure remains undetected. Since there are many types of defects, including all forms of corrosion and cracking, there are also several types of pig with performance tuned for a particular type of defect. Provided the full range of pigs are available, all common types of defect can be detected before they grow sufficiently to cause a pipeline to fail.
