Pipeline pigs play a role both in the commissioning of new and renovated pipelines and in the operational maintenance of pipelines. During the pre- and commissioning phase of pipeline construction, specific pigs are used to prepare the pipeline for operation and to perform a baseline assessment for validation that the pipeline condition meets physical design specifications. Anticipating threats to the pipeline during operation will help determine the pigs to be used to keep the pipeline safe and to manage risk.

Some pig assemblies can be rebuilt, and others will be discarded after use and we will discuss the benefits of each. This paper will explore the differences between commissioning and maintenance pigs and describe the value of each type. It will also provide insight into establishing an appropriate interval for maintenance pigging.