Overview
EN ISO 80000-3:2020/A1:2025 is Amendment 1 to Part 3 of the ISO 80000 series, Quantities and units - Space and time. Published as a CEN-endorsed amendment in 2025, it updates terminology, notations and normative references used to express physical quantities and units related to space and time. The amendment aligns Part 3 with the International System of Quantities (ISQ) and the International System of Units (SI) where applicable and clarifies several mathematical expressions in the standard’s tables.
Key Topics
- Normative references: Adds an explicit normative reference to the BIPM publication The International System of Units (SI), 9th edition (2019).
- Terminology alignment: Revises wording to reference the International System of Quantities (ISQ) (see ISO 80000-1) rather than older phrasing about base quantities in the SI.
- Table 1 revisions: Updates names, remarks and notational details for multiple items in the Part 3 quantity table, including:
- Clarified area and spherical-coordinate descriptions (explicitly defining A as the area delimiting a solid angle).
- Corrected notation for differential area elements.
- Replaced instances of the terms “phase velocity” and “group velocity” with “phase speed” and “group speed”, and removed the older velocity entries from the index.
- Small editorial corrections to formulae and symbol usage (e.g., c = ω/k, c = λ f, and dg/dk forms retained but expressed using “speed” nomenclature).
- Index updates: Deletes legacy index entries for “phase velocity” and “group velocity” to reflect the new terminology.
Applications
This amendment is practical for professionals and organizations that require consistent and up-to-date definitions, symbols and notations for spatial and temporal quantities:
- Scientists and engineers working in physics, astronomy, geodesy, acoustics and electromagnetics who must use standardized terminology and formulae.
- Standards bodies and technical committees implementing or endorsing EN/ISO standards at national and regional levels.
- Technical authors, educators and publishers preparing instructional material, scientific papers or textbooks that must comply with current international conventions.
- Software developers and metrology system designers who implement physical quantity libraries, unit conversion tools or measurement-data formats.
Related standards
- ISO 80000-1 (General principles of quantities and units / ISQ)
- BIPM The International System of Units (SI), 9th edition (2019) - now a normative reference for this part
This amendment ensures clearer, consistent usage of terminology and notation for space-and-time quantities, improving interoperability across scientific, engineering and metrology applications.