Horizon Pipeline Company, L.L.C.

Original Volume No. 1

Effective Date: 04/18/2002, Docket: CP00-129-001, Status: Effective

Original Sheet No. 202 Original Sheet No. 202 : Effective

GENERAL TERMS AND CONDITIONS

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the arithmetical 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 Heating Value and specific

gravity of the gas delivered during each day. In the event

electronic computer measurement is used, the determination of

Heating Value and specific gravity from chromatograph or

calorimeter and gravitometer transducers shall input continuously

into the computer for volume calculations. In the event a

continuous gas sampler is installed, then the Heating Value and

specific gravity shall be determined in the laboratory by

chromatograph and/or running a portion of test sample through a

calorimeter and gravitometer. Such determinations shall be

considered as the Heating Value and specific gravity of all gas

delivered during the applicable period of sampling. All Heating

Value and specific gravity determinations made with a

chromatograph shall use physical gas constants for gas compounds

as outlined in ANSI/API 2530 First Edition (Orifice Metering of

Natural Gas) with any subsequent amendments or revisions which

Horizon may adopt in exercise of his reasonable judgment. The

calculations (for Btu) shall be based on dry gas if the gas at the

measurement points contain less than five (5) pounds of water per

MMcf. If the gas at the measurement points contains more than

five (5) pounds of water per MMcf, the appropriate factor

determined by Horizon in the exercise of his reasonable judgment

for the actual water vapor content will be applied to the Btu

calculations to correct for this water content.

18.5 SUPERCOMPRESSIBILITY

The measurement hereunder shall be corrected for

deviation from Boyle's Law at the pressures and temperatures under

which gas is measured hereunder by the use of the Formula NX-19

appearing in the manual entitled, "PAR Research Project NX-19,

Extension of Range of Supercompressibility Tables," AGA Catalog

No. 48/PR published by the American Gas Association in 1963 as

supplemented or amended from time to time. Inert content of the

metered gas stream used in the Formula NX-19 calculations shall be

determined by a chromatographic analysis using spot sample when

deliveries begin and thereafter by chromatographic analysis no

less than semiannually or by more frequent continuous sampling or

by continuous computer input at each of the points where the gas

is received and delivered.