Overview

TC Energy contracted with Entech to provide design services for pneumatic testing of four pipelines covering six (6) Hazardous Classification Areas (HCAs). To allow for continuous service through the nearby town, two one-hour pneumatic tests were utilized and temporary Compressed Natural Gas (CNG) services were utilized in high-usage locations. In addition to the pneumatic testing of the pipeline, one branch pipeline and additional equipment were replaced during the outage.

Entech worked closely with TC Energy to review the existing pipeline condition, maintenance records, and pipeline information. Each of the six HCA locations was visited for site walk-downs, risk assessment, and documentation of existing conditions.

Two pneumatic tests were utilized to test the combined HCA locations, consisting of an upstream mainline and downstream service line test. Isolation for the first, upstream test was provided by blind flanges, spectacle blinds, and cutting and capping of the mainline. A temporary steel bypass was constructed to allow for a local meter station to continue to receive and distribute gas locally. Through the first pneumatic test, one of the branch lines and equipment was replaced to allow for ease of testing in the future.

Isolation for the second, downstream test was provided by blind flanges, spectacle blinds, and cutting and capping on the mainline and branch lines. At two locations CNG tankers were utilized to allow for uninterrupted service to each location. In addition to testing the downstream HCAs, Nondestructive Examination (NDE) was used to examine an area of a branch line that did not have sufficient documentation prior to testing.