PSC 134.291 Statistical sample testing plan for new meters.

PSC 134.291Statistical sample testing plan for new meters. The following new meter sample testing plan may be used for testing new meters instead of the new meter test requirements of s. PSC 134.26 (1), if the commission authorizes the adoption of the plan by a utility.#

(1)Meters, as received from the manufacturer, shall be divided into homogeneous lots by manufacturers and types. The maximum number of meters in any lot may not exceed 1,000 or be less than 96. From each such lot assembled, there shall be drawn a coded sample size specified in Military Standard 414 (MIL-STD-414) dated 11 June 1957, as shown for the various group sizes using Inspection Level IV of Table A-2 on page 4 and a corresponding actual sample size as shown on Table B-3 on page 45. The sample shall be drawn by a random method that ensures that each meter in the lot has an equal chance of being selected.#

(2)The test criterion for acceptance or rejection of each lot shall be based on a separate analysis conducted at both the open and check flow rate, as specified in s. PSC 134.28 (1) by means of the Standard Deviation Method, Double Specification Limit and with an Acceptable Quality Level (AQL) of.25 for the open accuracy analysis and an AQL of.40 for the check accuracy analysis as shown in Table B-3, MIL-STD-414, page 45. The statistical analysis calculations shall be made following the example on page 43 of MIL-STD-414 with the upper and lower specification limits U and L designated at 101% and 99% respectively.#

(3)One nonregistering meter may be removed from the sample lot for analysis purposes and replaced with another randomly selected meter. If more than one meter in a sample is found not to be registering, the entire lot shall be rejected.#

(4)A lot shall be deemed acceptable for installation if the total estimated percent defective (P) is less than the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub. (2). All meters in an acceptable lot shall be deemed to have met the accuracy requirements of s. PSC 134.26 (1) for placement in service without further testing.#

(5)A lot shall be considered rejected and not acceptable for installation if the total estimated percent defective (P) exceeds the appropriate maximum allowable percent defective (M) as determined from Table B-3 under the procedures of sub. (2). All meters in a rejected lot shall be tested and adjusted in accordance with the procedures of s. PSC 134.27 or replaced with meters meeting these requirements.#

Note: Military Standard 414 is on file at offices of the Public Service Commission, Secretary of State and Legislative Reference Bureau offices.#

History: Cr. Register, November, 1989, No. 407, eff. 12-1-89.#