EN ISO 14405-2:2019

Overview

EN ISO 14405-2:2019 - Geometrical product specifications (GPS) - Dimensional tolerancing - Part 2: Dimensions other than linear or angular sizes (ISO 14405-2:2018) explains the limits of using traditional ± tolerancing for dimensions that are not linear or angular sizes and shows why geometrical specifications (GD&T) are the preferred, unambiguous option. The standard, adopted by CEN as EN ISO 14405-2:2019, illustrates specification ambiguity that arises on real workpieces due to form and orientation deviations and demonstrates how geometrical tolerancing avoids that ambiguity.

Key topics and requirements

• Specification ambiguity: For dimensions other than linear or angular sizes, ± tolerancing can be ambiguous when applied to a real part. The document explains this ambiguity and why it is problematic.
• ± tolerancing vs. geometrical specifications: ± tolerancing is acceptable only for linear sizes (see ISO 14405‑1) and angular sizes (see ISO 14405‑3). For other distances and dimensions, use geometrical tolerancing (ISO 1101) to create clear, testable requirements.
• Illustrative examples and guidance: Clause 7 contains examples (linear distances between integral/derived features, radii, non‑planar features, two‑directional distances, etc.) showing ambiguous ± tolerancing and how to replace it with unambiguous geometrical specifications.
• Annex A: Informative explanations and examples demonstrating ambiguity introduced by ± tolerances (including references to common general tolerance standards such as ISO 2768‑1 and ISO 8062‑3).
• Annex B: Relation to the ISO GPS matrix model and how this part fits in the GPS system.
• Normative links: The standard references ISO 1101, ISO 14405‑1, ISO 14405‑3, ISO 8015, ISO 14253‑1 and other GPS foundational documents.

Practical applications and users

Who uses EN ISO 14405‑2:2019:

• Mechanical designers and CAD modelers specifying tolerances
• Quality engineers and metrologists defining inspection criteria
• Manufacturing engineers and process planners ensuring producibility
• Standards committees, technical writers, and auditors implementing GPS practices

Practical benefits:

• Reduces ambiguity in drawings and 3D models
• Improves manufacturability and inspection reproducibility
• Clarifies acceptance criteria for derived features, distances and non‑size dimensions
• Enables consistent application of GD&T (ISO 1101) across supply chains

Related standards

Relevant documents to use together with EN ISO 14405‑2:

• ISO 14405‑1 (linear sizes) and ISO 14405‑3 (angular sizes)
• ISO 1101 (geometrical tolerancing - form, orientation, location, run‑out)
• ISO 8015, ISO 14253‑1, ISO 14638, ISO 17450 series
• ISO 2768‑1, ISO 8062‑3, ISO 2538‑1/2 (wedges), ISO 3040 (cones)

Using EN ISO 14405‑2:2019 helps teams move from ambiguous ± indications to robust geometrical specifications, improving design clarity, inspection, and quality control.