Overview
EN ISO 80000-3:2020 (ISO 80000-3:2019) - "Quantities and units - Part 3: Space and time" is a sector-neutral standard that defines names, symbols, definitions and units for quantities of space and time. Where relevant, it provides conversion factors and concise formulations (for example, differential elements and basic relations). The document was prepared by ISO/TC 12 and adopted by CEN as EN ISO 80000-3:2020, superseding earlier editions.
Key topics
The standard organizes space- and time-related quantities into a consistent, machine- and human-readable table format. Major topics include:
- Fundamental quantities: length and duration (noting they are base quantities in the International System of Quantities - ISQ).
- Linear and geometric measures: length, width/breadth, height/depth, thickness, diameter, radius, path length, distance, radial distance.
- Vector and curve quantities: position vector, displacement, radius of curvature and curvature (κ = 1/ρ), path differential expressions.
- Area and volume: surface and volume elements (including expressions in Cartesian and spherical coordinates).
- Angular quantities: plane angle, rotational/angular displacement (ϕ = s/r), phase angle, solid angle (sr) and its differential in spherical coordinates.
- Kinematic quantities: velocity (vector) and speed, acceleration, angular velocity (ω) and angular acceleration (α).
- Time-related parameters: period (T), time constant (τ) for first-order responses, number of rotations.
- Units and symbols: SI-derived units and commonly used symbols (m, s, rad, sr, m·s−1, m·s−2, etc.) and guidance on signs and conventions (e.g., signed height, direction conventions for angular velocity).
Applications
EN ISO 80000-3 provides authoritative, standardized terminology and units that help eliminate ambiguity across disciplines. Typical uses:
- Technical documentation, specifications and engineering drawings (consistent symbols and units).
- Metrology, calibration and laboratory reporting (clear definitions and conversion factors).
- Scientific publications and education (uniform definitions of curvature, path elements, solid angles).
- Software, CAD, simulation and GIS systems (standardized variable names and units for data exchange).
- Instrument and sensor manufacturers (consistent unit labeling and metadata).
Who uses this standard
- Engineers (mechanical, civil, aerospace)
- Physicists and metrologists
- Technical authors and standards developers
- Software developers for simulation/CAD/GIS tools
- Educators and researchers
- Test laboratories and calibration providers
Related standards
- ISO 80000-1 (General principles; ISQ base quantities and units)
- ISO 80000-2 (Mathematical signs and symbols used in the physical sciences)
- Other parts of the ISO/IEC 80000 series and IEC 80000 documents for domain‑specific quantities
EN ISO 80000-3 is essential for anyone needing authoritative, interoperable definitions of space and time quantities and their units.