SI units Archives

Realization of the Kelvin

ByRandy Long, Senior Manager of Accreditation June 23, 2023May 21, 2025

Until 2019, the kelvin (K) was defined as “the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.” The temperature measurement world…

Measuring mass is confusing on 2019 World Metrology Day from the change to the kilogram SI unit.

ANAB | Laboratory

Happy World Metrology Day: A Change to SI Units

ByRandy Long, Senior Manager of Accreditation May 20, 2019June 5, 2025

Effective on this World Metrology Day (May 20, 2019), the International System of Units is now based on a set of definitions each linked to…

Twisting measuring tape representing the metric system (SI units), which are reflected in standards by an M.

ANSI | Welding

The “M” in Standards

ByBrad Kelechava March 12, 2018May 29, 2025

Regardless of industry, each standard has a unique designation, each component of which conveys its background. In these designations, numbers (and some letters) represent the…