This standard covers the various types and classes of cold water compound type meters in sizes 2 in. (50 mm) through 10 in (250 mm) and the materials and workmanship used in their fabrication. Compound meters shall consist of a combination of a main line meter of the turbine type for measuring high rates of flow and a bypass meter of appropriate size for measuring low rates of flow. The compound meter shall have an automatic valve mechanism for diverting low rates of flow through the bypass meter.