Profile: Pigging Products & Services Association (PSA) plays a major role in providing information and sourcing pigging equipment and services for pipeline operators. Pipeline pigs are devices that are inserted into and travel throughout the length of a pipeline driven by a product flow. They are developed to remove deposits which could obstruct or retard flow through a pipeline. Gel pigs are a series of gelled liquid systems which have been developed for use in pipeline operations, either during initial commissioning, or as a part of a continuing maintenance program.