Line Stopping Procedure

Bypassing large diameter sewers for repair, replacement, or rehabilitation. Line stopping involves using special equipment and techniques to stop the flow in the pipe and bypass it around tha damaged section so that replacement can be made.

The process goes like this:
step 1: First, a saddle and tapping valve is placed on the old pipe and the hot tapping (Cutting) machine is mounted on top of the tapping valve.

step 2: The tapping valve is opened, and the cutter is advanced through the top of the pipe. The housing of the hot tapping machine contains

step 3: Then, the cutter is retracted back into its housing, the cutter and hot tap machine are removed, and the linestopping machine is placed on top of the tapping valve.

step 4: The bypass pipe is attached to the linestopping machine, the tapping valve is opened, and the flow fills the bypass pipe.

step 5: The plugging head is dropped into position, stopping the flow and isolating the downstream section of old pipe.


When the permanent bypass is complete, the plugging head is retracted, the tapping valve is closed, and the linestopping machine is removed.

Thank you for good information from
Paul Wilting, P. Eng.
Senior Project Engineering
Greater Vancouver Regional District.
& Allan Herle, P. Eng.

Presented at:
No Dig 1999 Conference
North America Society for Trenchless Technology
orlando Florida May 23-26, 1999