NIST (National Institute of Standards and Technology) Measurement Services: Mass Calibrations

摘要

The NIST calibration service for standard masses is described. Weights which are accepted for calibration range in nominal values from 1 mg to 13,600 kg (30,000 pounds). Weights used to generate standard pressures in piston gages are also accepted. Cleaning procedures used on weights prior to calibration are described. The measurement algorithms (including density determinations of single-piece kilogram weights) and the uncertainties assigned to calibrated weights are discussed. The system now in place to monitor the quality of calibrations is described. Finally, the limitations of the present controls on measurement quality and outline improvements which are underway are assessed.