ISO 4435:2003 specifies the requirements for unplasticized poly(vinyl chloride) (PVC-U) pipes, fittings and piping systems intended for use for non-pressure underground drainage and sewerage for the conveyance of soil and waste discharge of domestic and industrial origin, as well as surface water.

It covers buried pipework but does not apply to piping systems buried within the building structure.

It is applicable to PVC-U pipes with or without an integral socket.