TRENCHLESS

UNDERGROUND PIPE REPLACEMENT

Prepared by Lee Clifton, Sr. Building Inspector

City of Los Angeles

Trenchless Underground Pipe Replacement

• The method of replacing sewer lateral replacement of old sanitary sewer laterals without the need to excavate trench by “ Trenchless Replacement & Inspection Corporation” using tools made by “TRIC Trenchless”.

• RR-5508

Details

• This method uses a special splitting head attached to the new sewer pipe at its tip. The splitting head is pulled through the existing pipe with the new sewer pipe trailing.

The approval is subject to the following conditions:

• 1. This method may be used for gravity drainage systems up to 6 inches only.

• 2. The replacement tubing, fittings, couplings and cleanouts shall be approved type in accordance with the city of Los Angeles plumbing Code and ASTM F714 and D2683.

• 3. An accurate and complete video inspection shall be performed in order to determine the location and depth of all “wye” connections, tees and access holes.

• 4. The pulling hole shall have the most stable soil available to withstand the large forces developed by the ram.

• 5. The pulling hole shall be large enough to allow the set-up of the hydraulic puller, pulley base and resistance plate.

• 6. The side from which the host pipe comes through shall be flat and completely perpendicular to the host pipe.

• 7. The entry hole and the exit port for the splitting head and new pipe shall not force the new pipe to make an excessively tight radius bend in order to enter or exit, respectively. The minimum allowed bend radius shall be per the new pipe listing.

• 8. A plumbing permit shall be obtained.

• 9. Tools used in this pipe replacement method shall be permanently marked with manufacturer’s name and appropriate model number.

TRENCHLESS UNDERGROUND PIPE REPLACEMENT

• In the past underground pipeline has been replaced by digging a trench, and removing, then replacing the existing line before back filling it. This process is extremely labor intensive, and in some cases leads to extensive rebuilding to reconstruct surface improvements or landscaping.

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TRENCHLESS UNDERGROUND

PIPE REPLACEMENT ACEMENT

• Trenchless pipe replacement is a method of replacing existing underground plumbing without the need to dig a trench through its entire length. This eliminates the costs associated with rebuilding surface improvements, and the costs of digging the trench itself. In many cases the savings will be very significant.

BUTT FUSION

• Polyethylene pipe is joined by heat fusion. The ends of the pipe are melted and then the melted ends are held together and allowed to cool. The result is a seamless connection that provides the same strength as any other part of the pipe.

BUTT FUSION

• Normal pipe couplings can be used for attachment to existing plumbing. High density polyethylene pipe is used worldwide for pressure, water and natural gas utilities. Heat fusion and the pipe itself have been proven in these applications.

Square each pipe end to be fused.

Check the line-up of the pipe ends. Adjust the high-low.

Heater plate inserted between the alignedends and ends brought firmly into contact with the plate.

INSTALLER WATCHING FOR PROPER MELT

Heater plate removed while heated ends examinedfor completeness of melt.

Splitting head attached to pipe.

Pipe laid out ready to enter hole.

Pipe reamer.

Pipe reamer attached to drill.

Pipe cable being inserted.

Cable being fished through existing pipe.

End of cable connected to splitting head.

Opening for sewer connection at street.

Backing plate being lowered into place.

Hydraulic ram lowered onto pulley assembly.

Pulley assembly

Backing plate

Hydraulic ram

3/4” steel braided cable

Close up of hydraulic ram & pulley assembly.

Splitting head

Pulley assemblyHydraulic ram

Hydraulic ram

Ram operated by remote control.

Hydraulic power unit

Here the splitting head starts its approach towards the existing pipe opening.

Splitting head enters opening at sewer lateral.

Head cut & removed for final connection.

This method has long been popular below streets.

Slip lining

14” Bursting Head

Existing sewer ran parallel to sidewalk under planter.

ENTRY HOLE

A rod pusher cable is pushed through the damaged host pipe and attached to the pulling head.

Pipe bursting head starts entry into existing pipe.

Broken pipe expands into soil as new pipe is pulled through.

Operator controls equipment via remote control.

The pulling whole shall have the most stable soil available to withstand the large forces developed by the ram.

The pulling hole shall be large enough to allow the set-up of the hydraulic puller, pulley base and resistance plate.

Hydraulic ram pulls a foot a minute.

THE END