Converting a Pipeline to a Piggable Asset
A multi-phased operation transformed a ten mile segment of a 12-inch transmission line into a piggable asset. The project was completed without interrupting gas service to customers.
An eastern utility had a critical transmission line that wasn’t piggable. When pigging, a device is run through a pipeline for cleaning, inspection, and maintenance. It’s an essential tool for an operator to perform in-line inspections and compliance with evolving regulatory requirements
Success wasn’t by chance. Nearly three years of planning and coordination between the utility, construction crews and technicians laid the groundwork for a disciplined, methodical execution. Over the course of six months, the ten-mile segment of a 12-inch bare steel pipeline was successfully transformed.
12-inch TDW Double STOPPLE® in action
Each phase was carefully sequenced to maintain system integrity while advancing the line toward full piggability. Today, the modernized asset supports in-line inspection, proactive maintenance, and long-term operational reliability.
Phases & Challenge
Converting the line was a multi-phase operation that required modifying a live pipeline under pressure. Dozens of precision isolation and tie-in activities were coordinated before the final commissioning.
Each step was executed while the line remained in service, maintaining continuous gas delivery across rural, suburban, and urban areas. The high-pressure transmission line traversed varied terrain and fed into multiple regulator stations with stops supplying gas to communities, schools, and businesses.
Equipment and services from KERR principals T.D. Williamson, CECO Peerless and ZEVAC® were deployed at different stages. Technologies included double STOPPLE® operations, hot taps, bypass, cross compression, separation and ultimately, pigging.
Pipeline Modifications
Multiple bends and fittings throughout the system that prevented pig passage had to be systematically cut out and replaced. One by one, these components were removed and replaced with configurations suitable for pig passage.
Each modification required isolating a section of the live pipeline. This was accomplished using double STOPPLE® operations with bypass.
At each location:
Fittings and valves were installed on the live line
Hot tapping services created access points
TDW STOPPLE® heads were inserted to isolate the section
Temporary bypass lines maintained flow around the work area
There were multiple 12-inch STOPPLE® operations, with additional 4-inch double TDW STOPPLE® bypasses. STOPPLE® train?
The approach allowed crews to cut out bends, install new sections including TDW 3-WAY™ tees. Then, the pipeline configuration was restored in stages, while gas continued to flow.
Emissions Reduction Through Cross Compression
Managing trapped gas between isolated sections was a critical project component. Rather than venting methane to the atmosphere, cross compression technology was used.
ZEVAC® cross compression was used to capture gas from isolated sections.
TDW crews were trained to operate a ZEVAC® system, allowing gas to be extracted from isolated sections and redirected back into the pipeline.
This approach:
Eliminated unnecessary methane emissions
Avoided costly third-party service dependencies
Maintained operational efficiency throughout the project
Additional System Upgrades
During the project, the utility used the opportunity to complete additional operational improvements, including:
Replacing and upgrading sections of pipe
Relocating pipeline components for improved performance
Testing of a new advanced isolation technology, TDW SHiiELD® double block and bleed system with dual independent barriers during live pipeline isolation.
Preparing for Pigging
TDW D2000 Proseries closure on the pipeline.
Once the pipeline was fully modified, pigging operations were introduced using TDW pipeline pigs and D2000® closures.
A CECO Peerless filter separator was installed at the end of the line. During pigging, accumulated debris such as rust and sediment carried through the pipeline had to be removed from the gas stream. The filter separator ensured effective removal of these materials before gas re-entered the system.
Peerless Filter Separator removed sediment and debris from the gas stream
Results
The project was completed within six months without service interruptions or safety incidents.
[Need #] STOPPLE® operations completed successfully
Continuous gas service maintained throughout the project
Significant cost savings achieved by avoiding shutdowns
Methane emissions reduced through cross compression
Today, the transmission line is a modern, fully piggable asset compliant for ongoing inspections, maintenance, and long-term integrity management.
A winning formula for complex operations like these consists of meticulous coordination, proven technology and highly skilled teams.
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 assets.
Kerr Engineered Sales Company has been representing leading pipeline repair and performance companies in Eastern US since the company was founded in 1952. Seventy four years later, KERR remains a family business delivering the highest quality service and expertise.
ZEVAC Ventless Purge on a New Pipeline
See how ZEVAC cross compression purged a five mile section of new construction pipeline without venting. Using compressed air as a vacuum, the pipeline was cleared and feed gas was introduced into the system the next day.
ZEVAC technology purged a 12" diameter new construction pipeline.
See how ZEVAC cross compression was used to do a ventless purge on five mile segment new pipe, using compressed air as a vacuum. Pipeline feed gas was introduced into the system the next day.
Instead of releasing gas to the atmosphere, ZEVAC helps utilities safely capture and manage natural gas in pipelines. The pneumatic (air) powered and controlled technology eliminates the noise, permits, notifications, hazards, and difficulties of venting and flaring.
ABOUT ZEVAC
From mobile gas evacuation units to fully customized equipment and field services, ZEVAC enables a closed-loop system of capturing, transferring, and reusing natural gas during pipeline operations. The methane mitigation equipment reduces product loss, minimizes costly service calls, and supports safer, more efficient maintenance across the gas distribution network.
Since 1952, Kerr Engineered Sales Company has represented leading pipeline and performance equipment manufacturers across the Eastern U.S. With four generations of family leadership, Kerr continues to serve the industry with the same commitment to quality, reliability, and personal service that has defined our company for more than 74 years.
AGMSC APPALACHIAN GAS MEASUREMENT SHORT COURSE
Join the KERR team at 2025 AGMSC Appalachian Gas Measurement Short Course August 4-7, 2025 at Robert Morris University in Pittsburgh, PA.
Join the KERR team August 4-7, 2025 at the AGMSC.
The Appalachian Gas Measurement Short Course is the most highly regarded educational forum in the Natural Gas Industry. Since 1976, it has been hosted by Robert Morris University in Pittsburgh, PA. The KERR team will be exhibiting.
The 2025 schedule can be found here.
David Kerr, President of Kerr Engineered Sales, will be giving a hands- on workshop about Catalytic Heater Operations, Troubleshooting and Maintenance on Tuesday, August 5th. Bruest Catalytic Heaters are the world leader in flameless, gas infrared Catalytic Heaters.
Consolidated Analytical Systems (CAS) infrastructure will be on display outside the venue. Seth Cloran and Mathieu Touzin from CAS will be running a course on Online Measurement of Odorant and Natural Sulphurs Wednesday August 6, 8:30 am.
ZEVAC and other principals that KERR represents will be present at the exhibits and events.
Kerr Engineered Sales Company has been representing leading pipeline repair and performance companies in Eastern US since the company was founded in 1952. Seventy three years later, the company remains a family business serving customers with the highest quality service and expertise.
Our application specialists at Kerr Engineered Sales Company are also available for team presentations, lunch and learns and customer visits.
TDW FIRSTS: ISOLATION TOOLS & FITTINGS IN ACTION
To help a customer isolate a 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.
To help a customer isolate a 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
TDW ProStopp® DS Isolation Tool
An East Coast gas company needed to replace a section of bare steel pipe as part of their infrastructure upgrade program. They were also installing a new gas regulator station on the same project. The 3,200 foot section of 16” and 10” pipeline, needed to be replaced without shutting off service to any customers.
TDW recommended the use of Spherical 3-WAY Tees at both locations. With Stops set thru the Spherical Tees, the line could be isolated while gas was still allowed to travel thru the system thru the new permanent bypass that was welded between the outlet of the two spherical tees.
To isolate the section of pipe, TDW technicians deployed a 16” 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 Sealing Cups with a bleed port between to ensure secure isolation.
For isolating the 10-inch line, TDW deployed 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 the traditional method, 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.
ZEVAC® extracts gas from the isolated section and redirects it into the 16-inch line.
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 end caps. This permanently rerouted gas thru the spherical tees and into the new section of pipe.
Conditioning the Line
TDW TOR 3-WAY Tee Bypass
Another TDW first on this project, 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. Once the STOPPLE and the ProStopp were set, the TOR 3-WAY Tee 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 about 25,000 scf of 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 three years later, KERR remains a family business delivering the highest quality service and expertise.