As the demand for sewer lateral replacements continues to rise, the trenchless replacement method of pipe bursting is a continued practice used by plumbers.
What does that mean for the homeowner? Replacing their sewer lateral with pipe bursting means the job can happen while their driveway, porch, garden, and sidewalk are intact with no need to disassemble or destroy. Removing any unnecessary damage to their property that could happen with open-cut lateral replacement.
You can also replace the existing pipeline with a larger diameter pipeline.
For this article, the lateral bursting system that will be referenced is a Portaburst PB30 and PB13 Power Pack. The PB30 is an ideally designed 30-ton hydraulic cable machine that is specifically used for 2- to 6-in. work.
It uses a ¾-in. swaged cable that is strong and rigid making it easy to feed it through your existing pipeline without a problem. The machine is engineered to do a maximum pull of 150 ft at one time. Ideally, most lateral services are in the 20- to 80-ft range.
First, when a customer comes to our trenchless technology specialists with a project, they lay the project out on our burst questionnaire. We have modified this questionnaire over the years to require specific information that sets the job up for success.
This questionnaire requires the following:
- The location of the project.
- The specifications of the project.
- The pipe diameter that exists in the ground.
- The length and material of the existing pipe.
- The HDPE product it will be replaced with.
- The diameter of the new pipe.
All those questions are answered before anything else. Our application specialists will contact the customer and go above and beyond the original questions to get more clarification on the job, if they have been to the site, are they going to be able to fuse the pipe together as one unit and extend in or are we going to have to fuse it as we pull.
Before Pipe Bursting Begins
Before bursting, you will need to know how many aspect changes there are in the line, does the aspect change angles, or any 22-degree, 45-degree, 90-degree bends. All this information will determine how you set up the project. These are all the preliminary items you want to have before you set equipment up and to ensure you have everything you need to accomplish the project.
From a contractor standpoint, the first thing that needs to take place is excavation. You are going to excavate inside the home/basement where the sewer line exits the house and goes underneath the foundation. You will also excavate outside, usually right at the sidewalk before it becomes the municipalities property as there will be a clean out there.
After they excavate the two pits, then you’re going to set your machine up in the pit making sure that the face of the machine is sitting parallel to the flow of your pipes. Next, you’re going to feed the cable from the outside pit to the inside pit.
Inside the home, you connect your tooling. A PB30 uses a quick grip burst head that will slide on the end of the new pipe that when you tighten down the nose of it, it expands jaws from the inside out compressing against the steel on the outside of the head reducing the chance that it would pull off the end of your pipe. The head has a blade on it creating a high energy point to help fracture the existing pipe.
HammerHead offers two different style bursting heads, one specifically for lateral lines, the other has an off shoot that allows for you to pull your sewer service and a brand-new water service in at the same time. This is beneficial if you have a joint buried trench where they put more than one utility together. In older homes, with the possibility of lead lines in the same trench, you can pull a new water line in at the same time as the sewer line and reconnect it. This eliminates lead water lines and upgrades it to a new HDPE line at the same time you are replacing your sewer line.
Ready for Pipe Bursting
You have your head set up, you have determined if you need a blade or not and now the tooling string is set up. The cable that was fed through the pits now hooks up to your burst head and you are done setting up the inside work.
Outside, connect the cable to the pulling apparatus, such as your PB30, then you hook the machine up to its hydraulic power pack. If using the PB13 you will have a single level operation for consistency. It has a powered top jaw that grips that cable with a positive lock to minimize slippage to virtually zero and a mechanical lower jaw that allows you to pull without the pipe rebounding back.
The system cycles back and forth, pulling material from inside the home to the outside. If your new pipe is completely fused, you do not need to stop until job is complete. If you must stop to fuse the new pipe, stop at a designated length, and then continue pulling. Stopping to fuse does not cause interruption to the burst itself, it is a more time-consuming process.
Once the burst head enters the outside pit, it will go into the extraction cage/docking area and the new pipe has been installed.
Finishing the Work
To begin disassembly, you will need to release the tension on the cable first. You can then remove your jaws and lift the PB30 out of the pit. Once out of the pit, disconnect the cable from the burst head. Remove the extraction cage from the pit and now you are ready to disconnect the burst head from the pipe.
Once disconnected the piece of pipe that is sticking out will afford you enough area to reconnect to the existing line that continues to the municipalities mainline sewer. Once the connection is made, the job is complete.