One of the most common ways to replace severely damaged or broken sewer pipes is through the use of what is known as pipe bursting. It is a modern trenchless technology, which means that there is no need for a backhoe or major digging to repair the sewer line.
The basic idea is to replace the existing sewer line with a new, longer lasting material that will last for a number of years. Older sewer lines were made of cast iron or concrete.
The steps in pipe bursting are actually quite simple once you understand that the goal is not to remove the old pipe, but use it as a way to properly align the new pipe.
First, a medium sized hole is drilled to access one end of the existing sewer line. A device known as the bursting heads that is slightly larger in size than the existing pipe is inserted into to end of the line.
Right behind the bursting head is the new pipe.
The bursting head is pulled through the original line, breaking the original pipe while at the same time creating the hole for the new pipe.
As the bursting head makes its way through the original line, the space created is filled by the new pipeline.
There are certain conditions that must be present in order for pipe bursting technology to produce the results the property owner is looking for. Geological conditions are a big factor in determining suitability as well as the length and material of the original pipe.
Though the process is simple and straightforward, there are actually two types of pipe bursting techniques that can be applied: pneumatic and static. We will avoid being overly technical, but it is useful to know the differences so you can have a better idea of why one is preferred over the other in your particular situation.
The pneumatic method is used when pushing the bursting head through the old sewer line can be done through the pushing force of air. The front end of the head is connected to a winch which maintains a constant tension that works to keep the bursting head aligned and straight. You can think of the process as a hammer hitting a nail, with the other end of the nail being guided through the end point.
The second method is the static method. This is the one generally described in the step-by-step process above. Instead of the push from the insertion point of the bursting head, the bursting head is pulled through from the other end using a winch. Like the pneumatic method, the alignment of the bursting head depends on the guidance of the winch line.
Once the new sewer line is in, it will be tested for inner wall integrity and then connected to the other ends of the main line. A water flow test will be conducted to make sure no leaks or cracks occurred during installation.
One important point that can be overlooked is that pipe bursting is both a technology and a system. There are companies who manufacture pipe bursting systems, so it is not a matter of throwing different parts together and following the steps. How pipe bursting technology can replace sewer pipe lines is simple when a layperson thinks about it, but is actual execution requires professional training and equipment.