1. (1) Each meter test of a diaphragm type meter with a capacity of 2,400 cubic feet per hour or less shall consist of one proving at a rate of flow of 15 to 30% of the rated capacity of that meter and one proving at a rate of flow at 90 to 120% of the rated capacity of the meter. The capacity of the meter for test purposes shall be the capacity at one-half inch water column differential pressure.
2. (2) Each meter test of a diaphragm type meter having a capacity greater than 2,400 cubic feet per hour shall consist of one proving at a rate of flow of 15 to 30% of the rated capacity of that meter and one proving at a rate of flow of 90 to 120% of the rated capacity of the meter but not less than 2,500 cubic feet per hour. The capacity of the meter for test purposes shall be the capacity at one-half inch water column differential pressure.
3. (3) Rotary meters shall be tested at 2 loads with the minimum load at 10% of rating by the use of a portable or volumetric meter or other approved proving devices, or be given a differential test. In the latter case an original test record shall be set up immediately after installation; future differential test results shall be recorded and compared with the original test record.
4. (4) A test of an orifice meter shall consist of tests of the recording gauges, and the removal, inspection and measurement of the orifice.
5. (5) Temperature-compensated gas displacement meters when tested shall be proved to a base temperature of 60° Fahrenheit.
6. (6) Turbine-type meters shall be tested at 2 loads with the minimum load at 10% of rating by the use of a portable or volumetric meter or other approved proving devices, or be given a turbine blade, rotor and gear assembly spin test, either by manual or velocity rotation. Before a particular type turbine meter can be used, the manufacturer must file with and be accepted by the commission a minimum coasting time which will satisfactorily indicate the operating condition of the internal metering mechanism. For the spin test method a test record shall be set up; and the original and subsequent spin test results shall be recorded and compared with the specified minimum coasting time as filed with the commission for that type meter.

History

History: Cr. Register, February, 1959, No. 38, eff. 3-1-59; am. (3), Register, November, 1962, No. 83, eff. 12-1-62; cr. (5), Register, January, 1965, No. 109, eff. 2-1-65; cr. (6), Register, April, 1969, No 160, eff. 5-1-69; am. (1) and (2), Register, November, 1989, No. 407, eff. 12-1-89.