Northern Natural Gas Company

Fifth Revised Volume No. 1

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Effective Date: 11/01/2003, Docket: RP03-398-011, Status: Effective

First Revised Sheet No. 210 First Revised Sheet No. 210 : Effective

Superseding: Original Sheet No. 210




gas sample collected daily during the month, or any other method

mutually agreed upon. Such chromatographs shall be owned, operated

and maintained by Northern at representative locations on Northern's

transmission system, or as agreed upon.


The heating value of the natural gas received by Northern from its

various sources of supply and of gas received for transportation will

vary. However, Northern will operate its system such that the

heating value will not fall below 950 Btu per cubic foot.


The unit of volume "at 1,000 Btu per cubic foot" or "as adjusted to

1,000 Btu per cubic foot" shall mean one cubic foot of gas as defined

above and having an average total heating value of one thousand

(1,000) British Thermal Units. Such units of volume shall be

determined by multiplying the number of cubic feet of gas delivered

during any billing day by the factor arrived at by dividing the

average total heating value per cubic foot delivered on the previous

day by 1,000 unless otherwise agreed to by Northern.


To the extent that Northern does not have chromatograph information

for a Field Area point, and if the Btu changes after the 20th of the

production month, such Btu change will not become effective until the

beginning of the following month. If the Btu changes during the

period from the first of the month through the 20th, such Btu change

can be effective for the beginning of such month.


Supercompressibility. Determination of supercompressibility of

natural gas shall be calculated from chromatographic analysis of gas

samples taken at representative points as determined by Northern.


Gas Sampling and Analysis. Gas samples may be obtained and analyzed

by one of the following methods:


Portable Chromatograph. Chromatographic analysis of a spot

sample of gas taken at a representative location and analyzed on

site by means of a portable gas chromatograph.


Spot Sample. Spot sample of gas taken at a representative

location using a sample bottle and analyzed using a gas

chromatograph at a location remote from the sampling location.


Continuous Sample. Sampling continuously into a sample bottle

for a period of time at a representative location