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. Includes an outline of the design procedure and an example with the basis of design or design method. 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.