Overview
ISO 24496:2021 - Office furniture - Office chairs - Methods for the determination of dimensions specifies standardized measurement methods for determining the dimensions of office chairs. It provides a consistent test framework and measurement procedures (including use of a Chair Measuring Device, CMD) so manufacturers, test laboratories and specifiers can compare chair dimensions reliably. Important: this document does not set dimensional specifications or pass/fail criteria - it only defines how to measure.
Keywords: ISO 24496:2021, office chairs, measurement methods, chair dimensions, CMD, ergonomic dimensions.
Key Topics and Technical Content
- Scope and intent: Methods for determining chair dimensions; clarifies that dimensional requirements are not included.
- Terms and definitions: Standardized vocabulary for chair dimensions (e.g., backrest height, armrest height, lumbar support protrusion).
- Reference seating posture: A theoretical anthropometric posture (feet on floor, ~90° joint angles, erect trunk) used to relate chair measures to human dimensions.
- General measurement conditions: Preparation, tolerances, measurement uncertainty and angle sign conventions.
- Test equipment: Specification and use of the Chair Measuring Device (CMD) (Annex A contains CMD drawings/specifications).
- Measurement procedures:
- Chair set‑up and placement of CMD (initial and final positions).
- Initial measurements, measurements with components at minimum and maximum adjustments, and measurements without the CMD.
- Specific measured items include armrest height/length/width, distance between armrests, backrest angle to vertical, backrest height/width, lumbar support height/protrusion, horizontal backrest radius, and backrest/seat movement ratio.
- Reporting: Required test report items to ensure repeatable, comparable results.
- Supporting annexes:
- Annex A (normative) - CMD drawings and measurement method details.
- Annex B (informative) - anthropometric equivalents.
- Annex C (informative) - rationale for provisions.
Practical Applications and Who Uses It
- Manufacturers & product designers: to measure and document chair dimensions consistently during development and QA.
- Test laboratories & certification bodies: to produce repeatable measurement data for datasheets and comparisons.
- Procurement teams & specifiers: to compare candidate office chairs on an apples‑to‑apples basis.
- Ergonomists & researchers: to relate chair geometry to anthropometric data and ergonomic guidance.
- Trade standards harmonization: useful where national methods varied (draws on BIFMA, EN, DIN and other national CMD methodologies).
Related Standards
- ISO 9241‑5 (ergonomic principles for office work)
- ISO 7250‑1, ISO 20685, ISO 14738 (anthropometric data references)
- National and industry chair measurement methods referenced in the standard (e.g., BIFMA, EN 1335)
Using ISO 24496:2021 ensures consistent, reproducible measurement of office chair geometry, improving comparability, product specification clarity, and ergonomic assessment.
