Specifies the requirements for screwed couplings. Section 1 applies to recessed ring joint type. Section 2 applies to trapezoidal threads type. These couplings are used for effecting joins in pipelines in food processing plants. Both sections propose dimensions, tolerances, surface roughness materials, assembling and hygienic requirements for both welded-type and expanded-type male parts and liners and for nuts, ring joints or gaskets. In this revision new dimensions have been included. Appendices irrelevant for the industry with changing technologies have been deleted.