Wisconsin Administrative Code
Public Service Commission
Chapter PSC 134 - Standards For Gas Service
Section PSC 134.251 - Use of recording calorimeter for therm billing

Universal Citation: WI Admin Code ยง PSC 134.251

Current through August 26, 2024

(1) In the application of gas rates based on the therm, a recording calorimeter shall be used to determine the heating value of the gas being distributed to utility customers. These calorimeters will be located as set forth in s. PSC 134.25(2) and (3). They shall have such accuracy characteristics as to be able to measure the heating value of the gas to within + or -2 B.t.u., shall be able to reproduce these readings to within +or - 2 B.t.u., and shall be able to hold their accuracy over an extended period of time. The instruments shall be installed in accordance with the manufacturer's recommendations.

(2) Each utility selling gas shall file with the commission a complete installation report stating the following information: location of calorimeter, kind of gas tested, type of scale, uniform or split scale range, date installed, publication number of manufacturer's applicable book of instructions, outline of the building, the location of the calorimeter or calorimeters within the building, the size, length, gas pressure, and general route of the gas sample pipe from the supply main to each calorimeter and location of all secondary equipment necessary for the operation of the recording calorimeter.

(3)

(a) Each utility selling gas shall keep a chronological record of dates and results of tests and operations performed on the calorimeter to test and maintain accuracy.

(b) Twice every month the following tests shall be made:
1. Two days of each month shall be selected for the performance of an "as found" accuracy test, mechanical tests, adjustments, and an "as left" accuracy test of each recording calorimeter, and thereafter the specified accuracy tests, adjustments, and maintenance work shall be performed on the same days of each month insofar as practicable.

2. In making the accuracy tests on the calorimeter, the utility shall use reference natural gas which has been certified by the Institute of Gas Technology before cleaning parts or making any adjustments to either the tank unit or the recorder mechanism. The change from line gas to the certified gas should be made so as to have a continuous chart recording. The inlet pressure used should be the same for both calibration and subsequent operation.

3. If the "as found" accuracy test is within + or -3 B.t.u., no adjustment will be required and the instrument may be returned to service. If the "as found" accuracy test is not within + or - 3 B.t.u., maintenance shall be performed to restore the accuracy of the instrument.

4. In order that adequate information concerning each cylinder of natural gas which is to be used for the semi-monthly check tests be available at all times, the following information shall be entered on a form or in a log book provided for the purpose and also on a label or tag securely attached to each cylinder in which the gas is stored:
a. Institute of Gas Technology Cylinder Number.

b. Institute of Gas Technology Certificate Number.

c. Date cylinder was certified.

d. Date cylinder was received by the utility.

e. Heating value certified by Institute of Gas Technology.

f. Basis of the heating value in subd. 4. e.

g. Heating value to be used in the semi-monthly accuracy tests. This heating value will not include any plus or minus values. For example, if the heating value is 1,000 + or - 0.9 B.t.u. per cubic foot, the heating value is 1,000 B.t.u. per cubic foot.

h. Basis of the heating value in subd. 4. g.

(5) The original chart records produced by the recording calorimeters shall be dated, labeled, and kept on file for 6 years. A copy of the daily average heating value of gas and the results of the semi-monthly"as found" and "as left" test shall be sent to the commission each calendar month.

(6) A gravitometer may be substituted for the calorimeter equipment required to control standby or peak shaving plants in subs. (1) and (5) provided the heat content of the standby or peak shaving gas produced does not directly affect the therm billing of the gas customer receiving it.

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