While pigging is commonly associated with pipeline maintenance, it also plays several critical roles in hydrostatic testing. TDW can help pipeline owners and operators select the right pigging equipment and services for each step of the testing process.
Hydrostatic testing (hydrotesting) calls for filling a pipeline with water at high pressures to test the line’s structural integrity. The process is a mandatory part of the pre-commissioning process, but it also can be performed on in-service pipelines as part of the U.S. Department of Transportation’s periodic due diligence testing for service.
The role of pigging begins with ensuring that the line is clean and that debris from the pipeline’s construction, which could damage the pipeline and/or inspection equipment, has been cleared away. TDW can guide operators through the company’s wide array of cleaning pig options.
Pigs also are used to fill pipelines with water for the hydrotesting, and later, for de-watering. Drying the line is necessary to prevent product contamination, eliminate equipment freeze, reduce the possibility of corrosion once the pipeline is in full service, and to meet most customer contract delivery requirements. TDW can offer recommendations for batching and liquid displacement pigs, and also can help operators determine if chemical services are advisable to enhance pipeline cleaning.