This standard covers the thickness design of ductile iron pipe complying with the requirements of ANSI/AWWA C151/A21.51, Ductile Iron Pipe, Centrifugally Cast, for Water. Included are: an outline of the design procedure and an example; and, the basis of design or design methods. The bulk of the standard comprises tables that list thicknesses for standard laying conditions and certain depths of cover, water working pressure, working pressures and maximum depths of cover for standard laying conditions and standard pressure classes, and special thickness classes of ductile iron pipe. The major revisions in this edition of ANSI/AWWA C150/A21.50-96 include the following: the format has been changed to AWWA standard style; the acceptance clause (Sec. I.C) has been revised to approved wording; the truck load equation (Eq. 5) and the surface load factor (Eq. 6) have been modified to allow for a correct distribution of units; Table 6, surface load factors for a single truck on unpaved road, has been changed to match the revised surface load factor equation (Eq. 6); and, the statement concerning surge allowance in the hoop stress formula (Sec. 4.1.2 and Sec. 4.2.2) has been modified to note that if anticipated surge pressures are other than 100 psi (689 kPa), the actual anticipated pressure should be used.