What is the term for placing a smaller diameter pipe inside a larger pipe?

The correct term for placing a smaller diameter pipe inside a larger pipe is known as slip lining. This method is primarily used in the rehabilitation of existing pipeline systems, allowing for the renewal of the structural integrity of the larger pipe without the need for extensive excavation. By inserting the smaller pipe, slip lining effectively restores the flow capacity and minimizes leakage while maintaining the existing infrastructure.

This technique is advantageous because it causes minimal disruption to the surrounding environment and infrastructure compared to more invasive methods. It can be employed for various types of pipes, including those made from different materials, making it a versatile solution for many water and wastewater systems.

Other terms may refer to specific methods or expect different applications; for instance, pipe relining often involves applying a resin or lining to the existing pipe surface instead of inserting a separate pipe. Pipe bursting refers to a different technique where the old pipe is broken apart and simultaneously replaced with a new pipe, which is not the case with slip lining. Pipelining is less commonly used and can be ambiguous, often referring generically to the process of putting in pipelines rather than a specific technique for rehabilitation.