EN ISO 22081:2021 PDF

Overview

EN ISO 22081:2021 (ISO 22081:2021) is a GPS (Geometrical Product Specifications) standard published by CEN/ISO that defines rules for the definition and interpretation of general geometrical specifications and general size specifications as referenced in ISO 8015:2011, clause 5.12. It provides a consistent framework for indicating general tolerancing on technical product documentation (TPD) and 3D models, reducing repetitive individual annotations while clarifying scope and applicability.

Key topics and requirements

• Scope and applicability
  • Applies to general geometrical specifications and general size specifications (linear and angular) for integral features only (including features of size).
  • Does not apply to derived features, integral lines, or non-linear/non-angular dimensions (see ISO 17450-1 and ISO 14405-2).
• Rules for definition and interpretation
  • Specifies how to indicate general specifications in TPD and how they are interpreted when attached to multiple features.
  • Clarifies datum-system rules and how general specifications interact with individual feature specifications.
• Indication tools
  • Introduces tools and conventions to reduce the number of repeated annotations on drawings and models (an evolution from ISO 2768-2).
• Designer responsibilities and decision rules
  • Emphasises that designers must define functional requirements and select appropriate tolerances to avoid overlooking functions or over-constraining parts.
  • Default decision rules from ISO 14253-1 apply unless otherwise stated.

Practical applications

• Use ISO 22081 to:
  • Apply uniform tolerance rules across multiple similar features (holes, slots, faces) to simplify drawings and 3D annotations.
  • Improve clarity in technical product documentation for manufacturing, inspection and quality control processes.
  • Ensure consistent interpretation of general tolerances in CAD models and downstream verification workflows.
• Benefits include reduced drafting time, fewer drawing errors, and clearer communication between design, manufacturing and metrology teams.

Who should use this standard

• Mechanical designers and CAD modelers preparing TPD or 3D annotations
• Quality and metrology engineers responsible for verification and inspection
• Technical drafters and manufacturing engineers standardizing tolerancing practices
• Standards committees and organizations aligning GPS implementation across enterprises

Related standards

• ISO 8015 - GPS fundamentals and rule references used by ISO 22081
• ISO 17450-1 / ISO 17450-2 - GPS general concepts and models
• ISO 14405 (parts 1 & 3) - Size measurement (linear and angular)
• ISO 22432, ISO 25378 - GPS features and definitions
• ISO 2768-2 (superseded) - previous general tolerance practice

Keywords: EN ISO 22081:2021, ISO 22081, GPS, geometrical tolerancing, general size specifications, integral features, technical product documentation.