Precision Weights: Traceable vs. NVLAP* Weight Calibration Certificates

Do your requirements call for an internationally accepted quality standard?

Compliance to internationally recognised standards is important because this provides insight into the calibration process. The NVLAP* Weight Calibration Certificate, unlike the Traceable Certificate, adheres to the strict requirements of numerous quality standards that are proven to meet the customer’s needs. NVLAP* Weight Calibration Certificates that meet the ISO/IEC 17025:2005 (General requirements for the competence of testing and calibration laboratories) and ANSI/NCSL Z-540-1-1994 (Calibration Laboratories and Measuring and Test Equipment – General Requirements) standards, demonstrate Troemner’s quality processes are competent and support the scope of accreditation. This is accomplished through rigorous third-party independent audits of Troemner’s quality systems and measurement assurance processes. The NVLAP* Weight Calibration Certificate meets the requirements of these international standards for quality, and increases the level of competence for customers complying with the GMP and GLP requirements for their laboratories.

Do your SOP’s require documentation for the standards used and environmental conditions at the time of calibration?

Identification of the standards used allows the customer to view the type of mass comparator utilised for the calibration. Knowing the mass standards used, allows the customer to verify the right equipment has been operated to perform a competent calibration. The environmental data captured at the time of calibration is useful for the weight that was used to verify the balance. The air density at the time of calibration can be determined, and a correction for the customer’s laboratory can be calculated. The greater the difference in the air densities results in a greater error on the balance.

Lower uncertainties on the calibration matter?

Traceable Certificates have a higher uncertainty due to the nature of the calibration process. Weight calibrations performed by manual comparison will have an uncertainty component caused by the technician’s interaction with the mass comparator. In contrast, NVLAP* Weight Calibration Certificates for precision weights ranging from 1 milligram to 1 kilogram, are completed on a robotic mass comparator where the repeatability of the process becomes a smaller uncertainty factor than that of the manual calibration process. The robotic mass comparators provide the NVLAP* Weight Calibration Certificate with lower uncertainties and a greater confidence in the measurements.