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5622: Mass Calibration at NIST in the Revised SI

This 2-hour webinar will describe the planned transition from consensus value to individual realizations that will take place during the next decade, and specifically discuss how the National Institute of Standards and Technology (NIST) plans to disseminate mass during this period. The unit of mass was realized by the International Prototype Kilogram (IPK) for over 130 years. On May 20, 2019, all fundamental quantities of the International System of Units (SI) were tied to natural constants. In this revision of the SI, mass is tied to the Planck constant. For several years, the world has been engaged in measuring the Planck constant to very high precision, and with the recent Committee for Data on Science and Technology (CODATA) adjustment in 2017, the value of the Planck constant has been fixed with no uncertainty. For the first few years after redefinition, the world will use a consensus value for the kilogram realization rather than individual realizations from the Planck constant.

Learning Objectives:

At the end of the two webinar sessions, using notes and reference materials, participants will be able to:

  • EXPLAIN how NIST plans to disseminate mass in the next decade;
  • DESCRIBE the planned transition from the current mass traceability to the IPK, to traceability to a consensus value, to individual realizations from the Planck constant; and
  • EXPLAIN the criteria that will be used to determine when individual realizations will become in accepted.


OPTIONAL - Read the NCSLI article found at

Minimum Requirement(s):

This is an informational webinar.  No certificates will be issued.


This training webinar is open to government and industry metrologists working in the field of mass measurement. Priority will be given to state laboratory personnel who are part of the OWM recognition or NVLAP accreditation process.


There is no fee for this learning event.


Patrick Abbott
Phone: 301-975-4216
Email: [at] (patrick[dot]abbott[at]nist[dot]gov)

Technology Requirement(s):

The webinar will be a live stream, so participants must have a constant connection during the webinar (hard-wired is preferred).

1. Operating System (browser) configurations:

  • Windows
    • Windows 10, 8.1 (32-bit/64-bit), Windows 7 (32-bit/64-bit)
    • Microsoft Internet Explorer 11 or later, Windows Edge browser, Mozilla Firefox, and Google Chrome
    • For HTML Client - Google Chrome (v70.0 & above), Mozilla Firefox (v65.0 & above), and Edge (v42.0 & above)
  • Mac OS
    • Mac OS X 10.12, 10.13 and 10.14
    • Mozilla Firefox, Apple Safari, Google Chrome
    • For HTML Client - Google Chrome (v70.0 & above), Apple Safari (v12.0 & above), and  Mozilla Firefox (v65.0 & above)
  • Linux
    • Ubuntu 16.04; Red Hat Enterprise Linux 6
    • No application support is available for Linux. Users on Linux can attend meetings in a browser.
    • Google Chrome, Adobe Flash Player 23.02.

2. Mobile

  • The Adobe Connect app for iOS and Android requires Adobe Connect Server version 8.2 or later
  • Some features may not be enabled in all Adobe Connect meetings if one is using an Adobe Connect Server older than version 9.4.2 (required for Custom pods)
  • Google Android 4.4 or later
  • Apple iOS: iOS 8.1.2 or later

3. Media players

  • In order to access the event, you must have, at a minimum, Adobe® Flash® Player 13 or higher installed on your computer. Please visit to download the Flash Player.

4. Optional: If you have never attended an Adobe Connect meeting before:

* Adobe, the Adobe logo, Acrobat and Adobe Connect are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and/or other countries.




NIST / Office of Weights and Measures
NIST / Mass & Force Group

Created October 18, 2019, Updated July 23, 2020