Calculation of heating value and volume

§ 3175.125 Calculation of heating value and volume (a) The heating value of the gas sampled must be calculated as follows: (1) Gross heating value is defined by API 14.5, Subsection 3.7 (incorporated by reference, see § 3175.30) and must be calculated under API 14.5, Subsection 7.1 (incorporated by reference, see § 3175.30); and (2) Real heating value must be calculated by dividing the gross heating value of the gas calculated under paragraph (a)(1) of this section by the compressibility factor of the gas at 14.73 psia and 60 °F. (b) Average heating value determination. (1) If a lease, unit PA, or CA has more than one FMP, the average heating value for the lease, unit PA, or CA for a reporting month must be the volume-weighted average of heating values, calculated as follows: ER17NO16.066 (2) If the effective date of a heating value for an FMP is other than the first day of the reporting month, the average heating value of the FMP must be the volume-weighted average of heating values, determined as follows: ER17NO16.067 Where: HV i = the heating value for FMP i , in Btu/scf HV i , j = the heating value for FMP i , for partial month j, in Btu/scf V i , j = the volume measured by FMP i , for partial month j, in Btu/scf Subscript i represents each FMP for the lease, unit PA, or CA Subscript j represents a partial month for which heating value HV i , j is effective m = the number of different heating values in a reporting month for an FMP (c) The volume must be determined under § 3175.94 (mechanical recorders) or § 3175.103(c) (EGM systems).