ISO 80000-3:2019/AMD1:2025

Overview

ISO 80000-3:2019/AMD1:2025, titled Amendment 1 - Quantities and units - Part 3: Space and time, is an important update to the international standard governing the definitions, symbols, and units related to spatial and temporal quantities. Published by the International Electrotechnical Commission (IEC) in collaboration with ISO, this amendment supplements the second edition of ISO 80000-3:2019. The document ensures alignment with the latest scientific and technical consensus for quantities and units used to describe space and time, reinforcing uniformity across scientific, engineering, and industrial applications worldwide.

This amendment addresses terminological refinements, clarifications of fundamental quantities such as length and area, and updates in the use of velocity-related terms, especially phase and group speeds. By maintaining consistency with the International System of Quantities (ISQ) and the International System of Units (SI), ISO 80000-3:2019/AMD1 helps practitioners and organizations apply precise and standardized measurements vital for global interoperability.

Key Updates

• Terminology Enhancements
  The amendment revises terms like "phase velocity" and "group velocity," replacing them with "phase speed" and "group speed" to reflect current usage and reduce ambiguity in physics and engineering contexts.

• Normative References Update
  ISO 80000-3:2019/AMD1 introduces references to the 9th edition (2019) of The International System of Units (SI) by BIPM, emphasizing adherence to the authoritative unit definitions.

• Clarification of Quantities and Symbols
  Updates include clarifying length as a base quantity of the International System of Quantities rather than the International System of Units, aligning terminology more closely with ISQ principles.

• Mathematical Expression Corrections
  The amendment refines remarks in tables to accurately define physical relationships, such as correcting the differential area element expressions and defining the surface area curving a solid angle using spherical coordinates.

• Removal of Outdated Terms from Index
  Outdated velocity terms have been removed from the index to match revised terminology introduced throughout the document.

Applications

ISO 80000-3:2019/AMD1:2025 is essential for multiple industries and technological fields requiring precision in spatial and temporal measurements, including:

• Scientific Research
  Enables researchers to communicate and replicate measurements involving space and time quantities with universally accepted units and definitions.

• Engineering and Manufacturing
  Supports standardized design specifications and quality control processes in sectors such as aerospace, automotive, and civil engineering where spatial measurements are critical.

• Electrotechnical Systems
  Collaborates with IEC standards, guiding the uniform use of quantities in electronic and electrical equipment, including timing devices and electromagnetic wave studies.

• Metrology and Calibration
  Provides a foundation for national and international measurement standards, ensuring traceability and comparability of length and time measurements across laboratories.

• Academic and Technical Education
  Acts as a reference for textbooks, academic curricula, and professional training programs on measurement science and engineering.

Related Standards

• ISO 80000-1 – General principles on quantities and units, forming the basis for ISO 80000-3 and the entire 80000 series.
• BIPM SI Brochure (9th Edition, 2019) – Provides the definitions of units referenced normatively in this amendment.
• IEC/TC 25 Standards – Related electrotechnical standards developed jointly with ISO technical committees, ensuring harmonized unit usage for electrical and electronic fields.
• ISO 80000 Series – Covers other measurement categories such as mechanics, thermodynamics, electromagnetism, and acoustics, useful for interdisciplinary applications involving space and time.

Summary

ISO 80000-3:2019/AMD1:2025 enhances clarity and consistency in the representation of spatial and temporal quantities and units. Its precise terminology revisions and normative updates are vital for global scientific communication and industrial standardization. Organizations and professionals involved in metrology, engineering, physics, and electrotechnology benefit from incorporating these updated standards, ensuring accuracy, compatibility, and compliance with international measurement frameworks.

Keywords: ISO 80000-3 Amendment 1, space and time quantities, International System of Units, ISQ, phase speed, group speed, measurement standards, spatial measurement, temporal quantities, international standards, metrology