Indiana Administrative Code
Title 170 - INDIANA UTILITY REGULATORY COMMISSION
Article 5 - GAS UTILITIES
Rule 1 - Standards of Service
Section 1-9.2 - Statistical quality control program; meters in service

(a) The statistical quality control program may apply to all temperature compensated and noncompensated standard type diaphragm displacement gas meters in service. One (1) of the following must be used as a reference in implementing the statistical quality control program:

(b) All meters in service shall be separated into homogenous groups by year set and may be further separated by manufacturer, capacity rating (or model), case type, diaphragm material, or other distinguishing characteristics. Where one (1) or more groups established are believed to be too small for practical quality control sampling, they may be combined with other groups of similar characteristics to establish a larger sampling base.

(c) The sample for each group, so far as possible, shall be taken from routine meter exchanges and removals for each year, except that those meters removed or exchanged because of known or suspected defects and for special tests may be excluded from the quality control sample. If the number of routinely changed or removed meters exceeds the sample required, the test sample will be randomly selected from these meters in accordance with widely accepted tables of random numbers. If an inadequate number of meters are routinely exchanged or removed, the balance of meters required for sampling will be obtained from meters in service by removal on a randomly selected basis in accordance with widely accepted tables of random numbers.

(d) During the first through fourteenth year in service, a meter group may be sampled to forecast service life and exchange requirements or to predict work loads. If this sampling is done, service life shall not be required to be curtailed because of results obtained in these premature sampling tests. In the fifteenth and subsequent service years, meter groups shall be sample tested annually, being allowed to continue in service until an annual sample reaches its rejection number or maximum allowable percent defective number of deviant meters.

(e) A meter group in its fifteenth or later year in service shall be removed from service during the calendar year following that in which the group sample test indicates a rejected lot. Removed meters shall be adjusted to meet the limits established under section 8 of this rule before being returned to service.

(f) If it becomes obvious that the rejected meters are predominantly from an identifiable subgroup, which may be shown by test data to have been affected by location, age, or other common factors, the suspect subgroup may be separated. The remaining members of the original group may be evaluated separately with the newly established group then becoming subject to the action indicated by its acceptance-rejection numbers.

(g) Any meter tested which exceeds an average accuracy figure of one hundred two percent (102%) or two percent (2%) above absolute accuracy of one hundred percent (100%) when tested at check and open rates shall be classed as rejected. The entire meter group from which the sample was taken shall be classed as rejected when the number of sample meters rejected equals or exceeds the appropriate reject number for that sample quantity or when the percentage of defective meters, from Table B-5 of the United States Military Standard #414, exceeds the maximum allowable percent defective for that sample quantity.

(h) The sample size code shall be determined from Table I, General Inspection Level II of the United States Military Standard #105-D, or a tighter level at the utility's option. The sample quantity and rejection number are then determined from Table II A of the United States Military Standard #105-D for the code letter determined and acceptable quality level (AQL) ten (10.0).

(i) The sample size code shall be determined from Table A-2, General Inspection Level IV of the United States Military Standard #414, or a tighter level at the utility's option. Sample quantity and the maximum allowable percent defective are then determined from Table B-3 of the United States Military Standard #414 for the code determined and acceptable quality level (AQL) ten (10.0). The population percent defective is then determined from Table B-5 of the United States Military Standard #414 and compared to the maximum allowable percent defective to determine acceptance or rejection.

(j) A public utility that elects to follow the sixteen (16) year periodic testing requirement, under section 9 of this rule, shall, by not later than March 1 of the succeeding year, file with the commission natural gas division a report of sufficient detail to verify compliance with the periodic testing requirement for a given year.

(k) A public utility that verifies the accuracy of meters by an approved statistical quality control program under section 9 of this rule, shall, by not later than March 1 of each year, file with the commission natural gas division a report of the results of sample tests for the preceding calendar year. This report shall be in such detail as to verify that the statistical quality control sampling tests were performed as set out in subsections (b) through (e).

(l) All flow and differential meters shall be checked for accuracy and, if found incorrect, be adjusted as near zero (0) error as practicable, at periods not to exceed three (3) months, in a manner satisfactory to the commission.