On an isolated section of a gas pipeline being upgraded and replaced, TDW employed three new applications of its technology, along with the first use of ZEVAC® cross-compression equipment.
Isolating the Lines
A gas line on the East Coast was being upgraded and replaced with bare steel replacement. The gas utility was installing a new regulator station. This section included 3,200 feet of pipeline, transitioning from 16 inches to 10 inches in diameter. To isolate the 16-inch line without interrupting gas for any customers, TDW technicians deployed a STOPPLE® Train, a patented system designed to isolate sections of pipeline for maintenance or repairs while the line remains in service. The STOPPLE® Train Isolation Machine uses double block and bleed technology, featuring two plugging heads to ensure secure isolation.
For isolating the 10-inch line, TDW introduced the 10-inch ProStopp® DS Isolation Tool, which also uses double block and bleed technology with two hydraulically activated plugging heads.
Redirecting Gas Instead of Venting
Once the isolations were set on the 16-inch and 10-inch lines, the trapped gas between the isolated sections needed to be removed so that the line could be cut and capped. Rather than venting the gas into the atmosphere, TDW technicians utilized a ZEVAC® (Zero Emission Vacuum and Compressor) Quad to extract the gas from the isolated section and redirect it back into the existing 16-inch line. Gas utilities implement cross-compression technology like ZEVAC for methane emissions reduction during live gas operations.
After depressurizing the line, the team secured the area overnight. Upon returning, they verified that the isolation seals were intact, providing a 100% shut-off. With no gas remaining, the utility safely cut out the old section and welded in the rerouted line.
Conditioning the Line
Another TDW first, TDW’s new 2-inch THREAD-O-RING™ (TOR) 3-WAY™ Tee was used to build a bypass line between the new and old pipelines. The utility did this two weeks before the isolation, when they were conditioning (pickling) the line. The TOR 3-WAY™ Tee fitting served as a purge and equalization fitting, compatible with TDW’s STOPPLE® plugging machines and other TDW equipment. Once set, the TOR Bypass was employed as the suction and discharge point for the ZEVAC® machine during line conditioning.
When the bypass was no longer needed, the TOR 3-Way™ Tee was isolated using TDW’s new Temporary Isolation Plug (TIP). Used for the first time on site, the TIP allowed the utility to safely decommission the outlet on the TOR 3-Way Tee. After both lines were capped off, the TOR Plugs were set in the TOR fittings, enabling the utility to complete the fittings.
Results
This complex isolation project was completed on schedule, allowing the utility to safely install the sections of pipeline without shutting off service to any customers. The new TDW technologies utilized in this project included:
TDW 10-inch ProStopp® DS Isolation Tool
TDW 2-inch THREAD-O-RING™ (TOR) 3-WAY™ Tee
TDW Temporary Isolation Plug (TIP)
Additionally, TDW technicians effectively operated a ZEVAC® Quad cross-compression unit to redirect gas back into the 16-inch line, effectively reducing the utility’s methane emissions. The collaboration between TDW’s isolation tools and ZEVAC® marked a successful first use of these combined technologies.
Our application specialists at Kerr Engineered Sales Company are available for demonstrations, team presentations, lunch and learns and site visits. We are here to help you optimize your gas utility operations and ensure the safety and efficiency of your equipment.
Kerr Engineered Sales Company has been representing leading pipeline repair and performance companies in Eastern US since the company was founded in 1952. Seventy two years later, KERR remains a family business delivering the highest quality service and expertise.
