Illinois Administrative Code
Title 83 - PUBLIC UTILITIES
Part 501 - STANDARDS OF SERVICE FOR GAS UTILITIES AND ALTERNATIVE GAS SUPPLIERS
Subpart B - NATURAL GAS MEASUREMENT REQUIREMENTS
Section 501.210 - Orifice Meters

a) A utility shall install all new orifice meters in accordance with the recommendation of AGA Report No. 3, Orifice Metering of Natural Gas and Other Related Hydrocarbon Fluids, Part 2, Specification and Installation Requirements, XQ0002 (April 2000 and June 2003).

b) A utility furnishing metered gas service through orifice meters shall provide and have available instruments capable of accurately determining the accuracy of the orifice plate diameters and instruments used to measure meter pressure and temperature to within 0.5 %.

c) At least every six months, a utility shall inspect an orifice meter's orifice plate and meter body and inspect and verify the proper operation of all transmitters used to measure pressures and temperatures.

d) If a utility discovers that the orifice plate is deformed, damaged or bowed, the utility shall replace the plate within seven days. If the utility finds that the orifice plate is deformed, damaged or bowed on two consecutive inspections, the utility shall document the problem and conduct inspections at least every three months on the orifice plate until three consecutive inspections show no damage. If the utility cannot obtain three consecutive inspections showing no damage after 24 months, the utility shall take corrective action, such as installing a strainer upstream of the meter, to avoid continued damage to the orifice plate.

e) A utility shall maintain five years of inspection records.