This European Standard specifies the requirements for the structural design of water supply pipelines, drains and sewers, and other water industry pipelines, whether operating at atmospheric, greater or lesser pressure. In addition, this European Standard gives guidance on the application of the nationally established methods of design declared by and used in CEN member countries at the time of preparation of this European Standard. This guidance is an important source of design expertise, but it cannot include all possible special cases, in which extensions or restrictions to the basic design methods may apply. Since in practice precise details of types of soil and installation conditions are not always available at the design stage, the choice of design assumptions is left to the judgement of the engineer. In this connection the guide can only provide general indications and advice. This European Standard specifies the requirements for structural design and indicates the references and the basic principles of the nationally established methods of design (see Annexes A and B).