This European Standard applies to waste water drainage systems which operate under gravity. It is applicable for drainage systems inside dwellings, commercial, institutional and industrial buildings. Differences in plumbing within Europe have led to a variety of systems being developed. Some of the major systems in use are described but this Standard has not attempted to detail the intricacies of each system. Detailed information additional to that contained in this Standard may be obtained by referring to the technical documents listed in Annex A.