The accuracy of the primary volume standards of the laboratory should be appropriate for the accuracy class of services provided. 7.3.5.3 Gravimetric methods, which generally use water as calibration media, require the verification of an adequate supply of deionized or distilled water. 7.3.5.4 Gravimetric methods require the use of weighing equipment with adequate accuracy and precision for the uncertainty of the measurement procedure. Appropriate control charts or range charts should be maintained to verify the measurement process. 7.3.5.5 Gravimetric methods require the means to adequately measure barometric air pressure, air temperature, water temperature, and relative humidity of the laboratory environment.
Volumetric methods require temperature measurements.
Environmental measuring equipment should be available with the accuracy indicated in Table 11. Relative humidity may need to be monitored more closely if evaporation is a concern. The algorithm chosen for the measurement, the reference standard to be used, and the equipment to be used for a particular calibration should be correct for that calibration. A documented procedure should be available in the laboratory to determine the correct algorithm. 7.3.6.2 Computer programs should have passed software quality analysis.