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.
TIPS TO CONSIDER WHEN PURCHASING CLOSURES
When selecting Closures, pipeline operators should consider safety and performance factors. The TDW D2000 Closures with the ProSeries™ Advantage is the safest, most trusted closure on the market.
“Imitation is the sincerest form of flattery that mediocrity can pay to greatness.”
Don’t compromise safety and performance by settling for imitations. When it comes to closures, cutting corners isn’t an option. The safety of your crews, the integrity of your pipeline, and the efficiency of your operation all hinge on choosing the right product.
TDW’s D2000 ProSeries closures are backed by more than 100 years of engineering expertise, field experience, and continuous innovation.
When you invest in the D2000 ProSeries, you’re not just buying a closure—you’re choosing the best-in-class solution backed by a manufacturer who will be here for the lifetime of your pipeline.
the manufacturer
Proven track record – Does the manufacturer have decades of field-proven reliability, or are they new to the market? TDW closures have been rigorously tested and trusted by operators worldwide for generations.
Life cycle support – A closure is only as good as its support. Look at availability of parts, repair services, and consumables like O-rings and Pressure Warning Locks (PWLs). TDW ensures long-term support for every component.
See the D2000 Closure in action
SAFETY FIRST
The primary question: Does the design keep the operator out of the danger zone?
Operator positioning – With the D2000, operators can safely open the closure from outside the direct line of danger.
Pressure Warning Locks – Placement matters. PWLs located in the 12 o’clock position are less likely to collect debris than those on the door face. The D2000 design directs any retained pressure safely away from the operator.
Durability and spares – Unlike metal-to-metal seals that wear out quickly, TDW’s PWLs are supported with readily available O-rings and replacement parts, ensuring reliability and uptime.
Design AND FEATURES that matter
Simplicity of operation – Fewer moving parts mean fewer failure points and easier maintenance.
Ease of alignment – A single pivot point makes aligning the door with the collar straightforward and efficient.
Clamping surface design – Closures with parallel, non-wedging clamp-rings eliminate force transfer to holding components, reducing wear compared to tapered, wedging surfaces.
O-Ring LOCATION and performance
Sealing performance is critical, and O-ring placement makes a big difference.
Protected placement – O-rings positioned on the external outer edge of the collar are less likely to be damaged during pig loading or removal, and they’re better protected from debris.
Leak prevention – Properly compressed O-rings perform even at low pressure, reducing leak risks.
Material options – TDW offers multiple O-ring materials to suit varying operating conditions, giving operators flexibility and reliability.
TDW closures are there for the lifetime of your pipeline.
DOWNLOAD CLOSURE BROCHURE
At Kerr Engineered Sales Company, we know closures inside and out. For over 73 years, we’ve been helping operators make the right decisions for pipeline safety and efficiency. As TDW’s representative since 1952, we stand firmly behind their products and their commitment to excellence.
CLOSING TDW D2000 CLOSURES
The D2000 quick-actuating closure combines operator safety with ease of operation. After depressurization, closing operations are performed in a fast, single motion. Here’s a quick guide to closing procedures.
TDW PIGGING INSIGHTS - Episode 6
A quick guide to closing and maintaining the D2000 Closure.
D2000 Quick-Actuating Closure
The D2000 quick-actuating closure combines operator safety with ease of operation. After depressurization, opening and closing operations are performed in a fast, single motion, with the operator standing safely to the side. The D2000 closure maximizes efficiency and reduces both, personal operator risk and company operational cost.
CLOSING PROCEDURES
Before closing, inspect, clean, and lubricate the O-Ring on the barrel collar, including the O Ring grooves and sealing surfaces
Push the door firmly shut with no gap between the door face and hub face.
Pull down on the clamp ring handle to close the door.
Install the pressure warning lock screw, make sure it is not cross threaded.
Hand tighten the pressure warning lock screw and then add about one eighth of a turn with a wrench. Do not over tighten.
MAINTENANCE TIPS TO BE DONE REGULARLY
Lubricate all the pivot point on top of the clamp ring assembly, front and back, as well as door hinge, top and bottom
Keep all the exterior surfaces painted to prevent rust
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If you have questions, please contact the Kerr Engineered Sales Company who are also available for team presentations, lunch and learns and customer visits.
OPENING TDW D2000 CLOSURES
The D2000 quick-actuating closure combines operator safety with ease of operation. After depressurization, opening and closing operations are performed in a fast, single motion. Here’s a quick guide to opening the closure.
TDW PIGGING INSIGHTS - Episode 5
A quick guide to opening and maintaining the D2000 Closure.
D2000 Quick-Actuating Closure
The D2000 quick-actuating closure combines operator safety with ease of operation. After depressurization, opening and closing operations are performed in a fast, single motion, with the operator standing safely to the side. The D2000 closure maximizes efficiency and reduces both, personal operator risk and company operational cost.
OPENING
To safely open the TDW D2000 clamp ring closure door, follow these procedures:
Isolate the vessel from line pressure, bleed the pressure to 0 psig and drain.
Always stand on the side of the closure that is opposite the door hinge.
Open the pressure warning lock by turning the screw counterclockwise. If there is still gas in the line, tighten pressure warning lock and continue to bleed pressure until 0 psig, then continue procedure again.
Inspect the pressure warning lock, O-Ring and the bushing.
Lift the clamp ring handle and put the pressure warning lock in the hole furthest to the right.
Clean and lubricate the interior surface of the clamp ring.
MAINTENANCE TIPS TO BE DONE REGULARLY
Lubricate all the pivot point on top of the clamp ring assembly, front and back, as well as door hinge, top and bottom
Keep all the exterior surfaces painted to prevent rust
Check out our Pig Resource page.
If you have questions, please contact the Kerr Engineered Sales Company who are also available for team presentations, lunch and learns and customer visits.