Definition - What does In-line Replacement mean?
In-line replacement is the process of installing or upgrading an old sewer line with a new pipeline on the same line. This process is similar to pipe bursting. Often the new installation has a higher load carrying capacity to improve the function of the sewer when there is a known increase in load. Old, cracked pipelines which cannot be restored are also replaced using this method.
Using directional drilling it is possible to replace old pipes without having to dig up yards, roads, and driveways.
Trenchlesspedia explains In-line Replacement
Most homes have plumbing that is over 40 years old which need to be replaced. Evidence of overworked sewer lines can be found in extremely green patches of vegetation, backups, and blocks. Traditionally it was required to dig up an entire stretch to replace the old pipes. Using techniques like pipe bursting, in line replacement can be done right from manholes. It also helps increase the existing capacity of the pipeline. Pipe bursting is done by inserting a bursting head through the insertion pit or manhole, ahead of the new pipe.
The nose diameter of the bursting head is slightly smaller than the host pipe to gain entry, while the base of the bursting head is slightly larger than the diameter of the host pipe to help fracture it. As the bursting head pushes out the broken pieces of the old pipe into the adjacent soil, the new pipe is pulled in and replaces the old pipe.