1. (1) Each utility shall maintain or have access to a meter shop for the purposes of inspecting, testing, and repairing meters. The shop shall be open for inspection by authorized representatives of the Commission at all reasonable times, and the facilities and equipment, as well as the methods of measurements and testing employed, shall be subject to the approval of the Commission.

   1. (a) The area within the meter shop used for the testing of meters shall be designed so that the meters and meter testing equipment are protected from drafts and excessive changes of temperature. The meters to be tested shall be stored in such manner that the temperature of the meters is substantially the same as the temperature of the prover.

   2. (b) Working Standards Each utility shall own and maintain, or have access to, at least one (1) approved bell type prover of five (5) cubic foot capacity, and all other equipment necessary to test meters, which shall be installed in the meter room.

      1. 1. Means shall be provided to maintain the temperature of the liquid in the meter prover at substantially the same level as the ambient temperature in the prover room.
      2. 2. The meter prover shall be maintained in good condition and correct adjustment so that it shall be capable of determining the accuracy of any service meter to within one-half of one percent (.5%). Each utility having meters which are too large for testing on a five (5) cubic foot bell prover may use a properly designed flow prover for testing the large meters.

   3. (c) Working standards must be checked periodically (see Rule 1220-04-05-.26(e)) by comparison with a secondary standard.

      1. 1. Bell provers must be checked with a one (1) cubic foot bottle which has been calibrated by the National Bureau of Standards.
      2. 2. Rotary displacement test meters must be checked with a bell prover of adequate capacity which has been calibrated by representatives of the National Bureau of Standards.
   4. (d) Extreme care must be exercised in the use and handling of standards to assure that their accuracy is not disturbed.
   5. (e) Each standard must be accompanied at all times by a certificate or calibration card, duly signed and dated, on which are recorded the corrections required to compensate for errors found at the customary test points at the time of the last previous test.
   6. (f) Each utility must have properly calibrated orifices, as may be necessary, to achieve the rates of flow required to test the meters on its system.

Authority: T.C.A. § 65-2-102. Administrative History: Original rule certified May 9, 1974. Editorial changes made by the Secretary of State pursuant to Public Chapter 305 of 1995; “Commission” and references to the “Commission” were changed to “Authority” and references to the “Authority”; effective March 28, 2003. Administrative changes made to this chapter on April 27, 2018 pursuant to Public Chapter 94 of 2017; “Tennessee Regulatory Authority” references were changed to “Tennessee Public Utility Commission,” “Authority” references were changed to “Commission,” “Authority Director” references were changed to “Commissioner,” and “Chief” references were changed to “Director.”