So, if your lab uses this method, you'll maintain NIST traceability, but you will also have greater measurement uncertainty. Remember that NIST traceable refers to an unbroken chain of measurements. A cal lab is not traceable to NIST, only the calibrations that the lab performs are traceable. But just because a lab uses equipment with NIST-traceable calibrations doesn't mean the lab follows accepted procedures for calibration. So, you can have a NIST-traceable calibration with unacceptable uncertainty.
Cal labs can, however, gain accreditation.
Accreditation means someone has verified that the lab uses appropriate equipment and follows acceptable procedures. The 1-VDC standard remains 1.018 V because that was the value of a DC voltage saturated standard cell. It's left over from when NIST used an artifact to generate the US national volt. Cahners Business Information , a division of Reed Elsevier . All rights reserved.