EZUD Accessibility Standards Compared: ISO, ANSI, EN, and WCAG
Accessibility Standards Compared: ISO, ANSI, EN, and WCAG
Navigating the landscape of accessibility standards can be overwhelming. Multiple organizations produce overlapping standards covering buildings, products, digital content, and organizational processes. This article maps the major standards bodies, their key accessibility standards, and how they relate to each other.
Standards Bodies Overview
ISO — International Organization for Standardization
A global federation of national standards bodies from over 160 countries. ISO standards are internationally recognized and often adopted as the basis for national standards.
CEN/CENELEC — European Committee for Standardization
Develops European standards (designated “EN”) that become mandatory in EU member states when referenced by EU directives.
ANSI — American National Standards Institute
Coordinates the U.S. voluntary consensus standards system. ANSI itself does not develop standards but accredits standards developers and approves American National Standards.
W3C — World Wide Web Consortium
An international community that develops web standards. The W3C’s Web Accessibility Initiative (WAI) produces the Web Content Accessibility Guidelines (WCAG), the dominant digital accessibility standard globally.
Key Standards by Domain
Built Environment
| Standard | Scope | Notes |
|---|---|---|
| ISO 21542:2021 | Building accessibility and usability | International standard for accessible built environments |
| ADA Standards for Accessible Design | U.S. building accessibility | Referenced by the Americans with Disabilities Act |
| EN 17210:2021 | European building accessibility | Functional requirements for built environment accessibility |
| ANSI A117.1 | U.S. accessible and usable buildings | Technical standard referenced by building codes including IBC |
| BS 8300:2018 | UK building accessibility | Design of an accessible and inclusive built environment |
ISO 21542 and EN 17210 cover similar ground with regional variations. ANSI A117.1 provides the technical basis for U.S. building code accessibility requirements, which are then enforced through the ADA and state/local building codes.
Digital/ICT
| Standard | Scope | Notes |
|---|---|---|
| WCAG 2.2 (W3C) | Web content accessibility | 87 success criteria at three levels (A, AA, AAA) |
| ISO/IEC 40500:2012 | Identical to WCAG 2.0 | Gives WCAG ISO status |
| EN 301 549 V3.2.1 | European ICT accessibility | Harmonized standard for EU Accessibility Act compliance |
| Section 508 (U.S.) | Federal ICT accessibility | References WCAG 2.0 Level AA |
| ATAG 2.0 (W3C) | Authoring tool accessibility | Standards for tools that produce content |
| UAAG 2.0 (W3C) | User agent accessibility | Standards for browsers and media players |
EN 301 549 is particularly important because it maps WCAG requirements to non-web ICT (software, hardware, documents) and adds requirements for things WCAG does not cover, like physical hardware interfaces and real-time communication.
Organizational Process
| Standard | Scope | Notes |
|---|---|---|
| EN 17161:2019 | Design for All management | Process standard for integrating universal design |
| ISO 9241-220:2019 | Accessible design | Processes for enabling accessibility in systems |
| BS 8878:2010 | Web accessibility code of practice | Organizational approach to web accessibility (UK) |
EN 17161 is notable because it is a management system standard — it specifies how organizations should integrate universal design into their processes, not what the end product should look like. This makes it complementary to product-level standards like WCAG.
Products and Services
| Standard | Scope | Notes |
|---|---|---|
| ISO 24751 series | Access for all in education/learning | Individualized accessibility in learning, education, and training |
| IEC 62803:2016 | Assistive technology interoperability | Specification for AT interoperability |
| EN 17161:2019 | Design for All in products and services | See above |
How Standards Relate
Several alignment relationships exist:
- ISO/IEC 40500 = WCAG 2.0 — identical content, different designation
- EN 301 549 references WCAG 2.1 — extends WCAG to non-web ICT
- Section 508 references WCAG 2.0 Level AA — may be updated to reference 2.1 or 2.2
- ADA references ANSI A117.1 — through building code adoption
- EU Accessibility Act references EN 301 549 and EN 17161 — for digital and organizational compliance
Choosing Which Standards to Follow
The appropriate standards depend on jurisdiction, domain, and organizational goals:
- U.S.-based digital products: WCAG 2.2 Level AA (exceeds Section 508 requirements)
- EU-based digital products: EN 301 549 (required by EU Accessibility Act)
- International digital products: WCAG 2.2 Level AA (globally recognized)
- U.S. buildings: ADA Standards for Accessible Design + ANSI A117.1
- EU buildings: EN 17210 (as adopted into national building codes)
- Organizational process: EN 17161 (regardless of jurisdiction)
For certifications built on these standards, see universal design certifications and standards. For the legal frameworks referencing them, see universal design legislation.
Key Takeaways
- Multiple standards bodies (ISO, CEN, ANSI, W3C) produce overlapping accessibility standards for buildings, digital content, products, and organizational processes.
- WCAG is the dominant digital accessibility standard globally; EN 301 549 extends it to non-web ICT for EU compliance.
- EN 17161 addresses organizational process; most other standards address product or content outcomes.
- Standards align through cross-referencing (EN 301 549 references WCAG; ISO/IEC 40500 is identical to WCAG 2.0).
Sources
- W3C — WCAG 2.2 Full Specification: https://www.w3.org/TR/WCAG22/
- W3C WAI — W3C Accessibility Standards Overview: https://www.w3.org/WAI/standards-guidelines/
- Section508.gov — IT Accessibility Laws and Policies: https://www.section508.gov/manage/laws-and-policies/
- ADA.gov — ADA Standards for Accessible Design: https://www.ada.gov/law-and-regs/design-standards/
- Centre for Excellence in Universal Design — Standards: https://universaldesign.ie/what-is-universal-design