(a) Each utility shall establish its own standard heating value for the gas it furnishes the public. At no time shall the daily average heating value be less than the established standard. The standard adopted by the utility shall be stated in its tariff as required by Puc 504.01(a).
(b) Each utility shall, unless it only takes gas from interstate pipelines, maintain equipment for measuring thermal content as follows:
(1) Each utility shall maintain a standard calorimeter outfit or gas chromatograph for the regular determination of the heating value of gas sold; and
(2) Each utility shall use the manufacturer's recommended procedures as a basis for:
a. Maintaining the accuracy of all calorimeters and gas chromatographs; and
b. The method of measuring heating value tests.
(c) The total heating value of the gas shall be determined at least once daily and more often as is necessary to obtain an accurate record of the average heating value and of the fluctuation in heating value.
(d) Each utility shall provide a definition in its tariff of the methodology used to determine the thermal heating value as required by En 504.01(b).
(e) To obtain the monthly average heating value the results of all tests of heating value made on any day during the calendar month shall be averaged, and the average of all daily averages shall be taken as a monthly average.
(f) If a utility's calorimeter or gas chromatograph is of the recording type, its record shall be used in determining the average heating value provided that the recording calorimeter or gas chromatograph is checked at least annually.
(g) Heating value reports shall be made on department “Form E-6, Heating Value and Purity Report,” dated October 2023 once a month pursuant to Puc 509.06.