Relining in the context of sewer rehabilitation can be defined as the process of repairing a damaged sewer pipeline by inserting a liner coated with resins that is expanded into the damaged pipe to create a lining within the pipe. This process is used in trenchless technology to repair leaking or broken pipes without having to replace the entire pipe and without the need for excavation.
Trenchlesspedia Explains Relining
Before the relining process is started, the affected pipe is inspected and cleaned of debris. Once cleaning is completed, the necessary length of liner is cut for insertion. The relining process uses a lining material of polyester felt coated with PVC. This liner is saturated with an epoxy resin and an hardening agent. The felt tube is then inverted into the pipe using water or compressed air, bringing the resin coated side towards the inner side of the pipe.
The tube is expanded until it fits into the pipe and left to cure or harden into the old pipe. These liners are strong and last for a very long time (at least 50 years) which makes the process cost effective.