What does ‘NIST traceability’ mean?

Everyone knows what “NIST traceability” is, right? Someone ‘checked’ your thermometer or hydrometer or other measuring device against another device which was “NIST traceable”, so now your instrument is ‘NIST traceable’...

What is the “traceability chain”?

Simply put, the number of “links” between the primary calibration (NIST) and the customer. The more “links’, or calibration transfers, the larger the measurement uncertainty. That cannot be avoided. Calibrate with ICL and minimize the links in the traceability chain...