This International Standard specifies the nature, the method of application, the surface condition and the minimum thickness of internal linings of cement mortar for ductile iron pipes and fittings for pressure and non-pressure pipelines as defined in ISO 2531 and ISO 7186. It covers cement mortar linings which are used to improve the hydraulic properties of pipes and fittings compared to un-lined pipes and fittings and/or to prevent corrosion damage and includes special requirements for linings of gravity sewers operating partially filled. It also covers linings used for the conveyance of particularly aggressive fluids, where the following solutions may be used either separately or in combination: a) an increase in the thickness of the lining; b) a change of the type of cement; c) a coating over the lining.