C702-78: AWWA Standard for Cold-Water Meters--Compound Type (PDF)

This standard covers 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 employed 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. Included are sections on the following: affidavit of compliance, basis for rejection, and metrication, choice of materials, main castings, register box rings and covers, measuring cages or chambers, measuring turbines and discs, disc and turbine spindles, intermediate gear trains, external fasteners, companion flanges, automatic valves, general design including size, capacity, length, pressure requirements, interior parts, registration accuracy, and markings, detailed design of the main case, external case screws, bolts, nuts, and washers, main case connections, companion flanges, tapped bosses, registers, register boxes, intermediate gear trains, measuring chambers or cages, measuring turbines and discs, magnetically coupled or direct drives, automatic valves, bypass meter, strainers, and seal wire holes. The appendix includes information on units of measurement, register types, tests and testing equipment, under and over registration, periodic tests, meter storage, bypass shutoff valves, service bypass around meter.