Swagelining’s versatility

Colorado water utility managers assess the versatility of a pipe-lining method called Swagelining.

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Owner: City of Fort Collins Utilities, Colo.


Engineer: Stantec Consulting
Prime contractor: Garney Construction
Prime contractor: Hydro Construction
Subcontractor: SAK Construction LLC

Why Swagelining?

The design/construction team was selected using the city’s Alternative Product Delivery System (APDS) methodology. With APDS, the team is selected based on qualifications, then works together and with the utility for the project’s duration.

After evaluating the full roster of trenchless rehabilitation methodologies, the team decided on Swagelining for both projects.

Swagelining is a method of lining using an HDPE pipe that can be a stand-alone pipe or a lining system that depends on the host pipe for structural strength.

A frame with a dye that’s about 10% smaller than the host pipe is set at an entrance pit just outside the host pipe. The HDPE pipe is pulled through the dye at continuous pressure, which reduces its outside diameter. When the pipe’s been pulled all the way through, the tension is released and the pipe begins to revert to its original diameter. After 24 hours, the liner pipe is tight against the host pipe and closure pieces (Fort Collins used steel) can be installed.

The primary reasons were the ability to maintain inner diameter, NSF approval for potable water, proximity of a local contractor, and HDPE’s ability to provide a continuous liner.

Swagelining: a very specific tool for a very specific job

For at least 30 years, U.S. water and sewer utilities have been able to slipline water, sewer, and storm pipelines with a trenchless construction method that has virtually no impact on capacity. Read More

Another advantage was that hydraulic capacity can be maintained, and even increased, depending on liner thickness and the existing pipeline’s C factor. Maintaining capacity was critical for the Poudre Canyon raw waterline due to water rights.

Probably the biggest benefit was being able to line upwards of 2,000 feet with one installation. The 2,000-foot spacing for entry pits satisfied Poudre Canyon’s strict surface-damage limits and enabled crews to avoid the Foothills project’s many street and yard obstructions.

In both cases, the host pipe remained the structural pipe to minimize liner thickness.

Next page: Pipe failed during installation

About the Author

Ken Matthews and Owen Randall

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