This standard covers the various types and classes of cold water compound type meters in sizes 2 in. (50 mm) through 8 in. (200 mm) and the materials and workmanship used in their fabrication. Compound meters shall consist of a combination of a turbine-type mainline meter for measuring high rates of flow and a bypass meter of an 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.