170 IAC 5-1-9.1 Approved statistical quality control program

Sec. 9.1. (a) A utility, at its option, may elect to use either of the following statistical quality control programs hereby incorporated by reference into the rules of the Indiana utility regulatory commission. Copies are available from the U.S. Government Printing Office Bookstores, One Congress Center, 401 South State Street, Suite 124, Chicago, IL 60605. (1) United States Military Standard #105-D, "Sampling Procedures and Tables for Inspection by Attributes", April 29, 1963. (2) United States Military Standard #414, "Sampling Procedures and Tables for Inspection by Variables for Percent Defective", June 11, 1957. (b) When using the method in subsection (a)(1), sample size code letters shall be taken from Table I, General Inspection Level II, or a tighter level at the utility's option. Sample size and acceptance-rejection numbers shall then be determined from Table II A, single sampling plan for normal inspection, using acceptable quality level (AQL) ten (10.0). (c) When using the method in subsection (a)(2), sample size code letters shall be taken from Table A-2, General Inspection Level IV, or a tighter level at the utility's option. Sample size and maximum allowable percent defective (M) shall then be determined from Table B-3, master table for normal and tightened inspection for plans based on variability unknown, using an AQL ten (10.0). (d) Meters for quality control sampling 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, at the utility's option, be combined with another group of similar operating characteristics to establish a larger sampling base. Combined groups shall have sample size and acceptance-rejection numbers based on the combined total of meters. (e) All meter groups, or combined meter groups, shall be subject to acceptance or rejection on the basis of the statistical results unless it becomes obvious that the rejected meters are predominantly from one (1) identifiable subgroup which may be shown by test data to have been affected by location, age, or other common factors. If this result should occur, the identifiable subgroup may be separated and the remaining meters treated as a new combined group with appropriate sample size and acceptance-rejection numbers. (f) Rejected groups, or subgroups, shall be scheduled for removal from service during the next calendar year and shall be adjusted to meet the limits established under section 8 of this rule before being returned to service.