To comply with federal Integrity Management Program requirements, a confidential utility client planned to complete pipeline integrity direct assessment inspections along unpiggable pipelines within its city gates and other valve site and interconnect facilities. Unpiggable pipelines are difficult to inspect internally with conventional in-line tools and require direct excavation and inspection, including internal corrosion direct assessment (ICDA) and external corrosion direct assessment (ECDA). The client retained Barr to draft outage procedures to detail necessary steps to temporarily route gas around the isolated area. The steps involved implementing temporary gas supply and meter and regulation skids; bypass piping; and alternative city gate supplies, followed by isolating, depressurizing, and purging the piping systems out-of-service; conducting pipe replacement; purging the system into service; and restoring the pipeline and facilities to regular operation.
The purge was completed according to AGA Principles and Practices guidance manual using air movers and throttling pipeline supply gas. Barr reviewed the requirements for temporary gas compression and supplementary compressed natural gas (CNG) trucks to supply downstream pipelines during the facility outage. Barr also coordinated with other facility and/or pipeline outages to minimize gas blowdown volumes and maximize the construction that could be safely executed during planned outages.
For instances where the client conducted direct assessment that resulted in the immediate execution of pipeline remediation, Barr’s design team expedited detailed design engineering to release construction plan drawings for the identified pipe sections to complete inspection and construction activities within the pre-planned outage timelines.
Vice President Senior Mechanical Engineer