LMK Dual Pipe CIPP Process

By Jeff Griffin, Senior Editor | May 2014, Vol. 69 No. 5
View from main showing the dual laterals.

LMK Technologies has developed and introduced a technology that permits the simultaneous application for a single-piece of CIPP (cured-in-place-pipe) liner for the main pipe and multiple branch pipes.

CIPP lining of sewer mains and laterals is not new, but until now, those methods required mainline pipes and laterals to be rehabilitated separately, said Larry M. Kiest Jr., LMK president and founder.

The technology was unveiled at the 2014 Underground Construction Technology International Conference & Exposition (UCT) and has been successfully used on several projects, said Kiest.

Qualified contractors can license use of the technology from LMK which manufactures lining and installation equipment.

“We developed a liner that would invert in the main pipe as the liner passed by two or three laterals and liner tubes begin to invert up the lateral pipes.” he explained. “The mainline liner continues to invert past the sewer service lateral pipes.

“The result is a single unit liner that renews a portion of the main pipe and multiple laterals all at one time.”

Kiest cites an example of a project in Fort Myers, FL, where a short section of main pipe and two opposing Siamese laterals, each 65 feet long, were lined with the process. Siamese laterals, he said, are two laterals exactly across from each other at 3 and 9 o’clock.

Compression gasket

All ends of the liner tubes are sealed by use of a compression gasket. “This is most important,” Kiest emphasized. “Otherwise the liners will leak because they do not bond to the mainline liner, allowing water to track behind the liner and reenter the sewer.

“We have done as many as three service laterals at one time. Our research and development department works continually to perfect the system to renew the entire pipe length from manhole to manhole and renew each lateral along the way through a continuous inversion of many liner tubes. In some cases, the lateral connects to the main pipe at 12 o’clock, extends up five to six feet, and deadheads into a bullheaded tee fitting that splits off into separate lateral pipes. We refer to this pipe configuration as double stack lateral liners.”

Basic equipment to implement the process is the same used for conventional CIPP installations and includes push cameras, lateral launch camera, steam boiler, wet-out trailer, robotic “positioner” and launchers to invert the lateral liner from the launcher into multiple lateral pipes.

Kiest describes the steps in making an installation:

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