This International Standard is a guidance document, defining families of techniques for renovation of non-pressure and pressure pipelines by use of plastics pipes, fittings and ancillary components. It provides guidance on the principles of, but not detailed methodologies for, the design of plastics piping systems applied as linings to existing pipelines, covering: - liner functions; - existing pipeline and site conditions; - technique related aspects; - structural aspects; - hydraulic aspects. It does not specify the calculation methods to determine, for each viable technique, the required amount of lining material needed to secure the desired performance of the renovated pipeline.