Transcolorado Gas Transmission Company LLC

Second Revised Volume No. 1

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Effective Date: 12/28/2007, Docket: RP08-167-000, Status: Effective

Original Sheet No. 261 Original Sheet No. 261 : Effective






10.1 Unit of Measurement and Metering Base. The volumetric measurement

base shall be one cubic foot of gas at a pressure base of 14.73 psia, at a

temperature base of 60 degrees Fahrenheit, without adjustment for water vapor.


10.2 Atmospheric Pressure. For the purpose of measurement, the

atmospheric pressure shall be the barometric pressure calculated for the

elevation at the point of measurement.


10.3 Temperature. The temperature of the gas shall be determined at

the points of measurement by means of a properly installed recording

thermometer or continuous electronic transducer input to a computer that

conforms to A.P.I. Standard 21.1 installed in accordance with the

recommendations contained in ANSI/API 2530 (Orifice Metering of Natural Gas),

as amended from time to time. The arithmetic average of temperatures for each

day shall be used in computing temperatures of the gas during such day for

conventional chart measurement. When electronic computer measurement is used,

average daily temperature will be computed as a running average of data

determined by computer scan.


10.4 Determination of Gross Heating Value and Specific Gravity. Where

TransColorado elects to install electronic computer measurement equipment and

field chromatographs, the determination of gross heating value and specific

gravity shall be made from the composition by calculation using physical gas

constants for gas compounds as outlined in GPA Standard 2145 (Table of

Physical Constants of Paraffin Hydrocarbons and Other Components of Natural

Gas) with any subsequent amendments or revisions that TransColorado may adopt.


Where TransColorado elects to install conventional chart

measurement, the arithmetic average of the hourly heating value and specific

gravity recorded during periods of flow each day by a recording calorimeter

and gravitometer or recording chromatograph, if installed, shall be considered

as the gross heating value and specific gravity of the gas delivered during

each day. If a continuous gas sampling device is used, determinations shall

be made not less than once every month. Such determinations shall be

considered as the gross heating value and specific gravity of all gas

delivered during the applicable sampling period.