ISO 18526-4:2020

Overview

ISO 18526-4:2020 - "Eye and face protection - Test methods - Part 4: Headforms" specifies the dimensions, tolerances and reference distances for the headforms used to test eye and face protectors. It defines adult and children headform classifications, provides anthropometric background (Annex A and B) and points testers and manufacturers to CAD files and measurement methods used to ensure consistent, repeatable testing of personal protective equipment (PPE).

Key topics and technical requirements

• Headform classification: Six adult headforms (1-S, 1-M, 1-L, 2-S, 2-M, 2-L) covering approximately 95% of the measured population. Child headforms include 1-C12 and 1-C6 (per CSA Z262.6), with guidance for type 2 child headforms when standardized forms are not available.
• Critical dimensions: Interpupillary distance (PD), bizygomatic breadth, outer/inner canthal distances, nasal breadths, nose bridge length, corneal apex-to-pinna distances and other facial landmarks important to eye/face protection fit and coverage. (Detailed tables and CAD files carry the nominal millimetre values.)
• Tolerances and drawing practice: Tabulated values and Annex dimensions are given with ±0.1 mm precision in the document; manufacturers’ headforms may deviate by ±2% from CAD data. Figures in the standard are illustrative - use the ISO CAD files for exact construction.
• Test features: Small test details such as pupil diameter (5 mm), pinhole for ear-point attachment (2.0 mm) and a 1.0 mm vertical reference for corneal apex-to-pinna placement are specified to standardize test set-up.
• Anthropometric basis: Annex A/B reproduce NIOSH 3D scan datasets (including US, Chinese and Japanese samples) and the NIOSH 2003 anthropometric survey (3,997 subjects), documenting the data sources used to derive headform sizes.

Applications and users

• Who uses it: PPE manufacturers, test laboratories, certification bodies, standards writers, and designers of safety eyewear, face shields and other facial protectors.
• Practical uses:
  • Building compliant headforms for performance testing (impact, coverage, optical alignment).
  • Verifying fit and coverage across a representative range of head sizes.
  • Harmonizing test procedures with other parts of the ISO 18526 series and product requirement standards (ISO 16321).
  • Supporting third‑party certification and market conformity checks.

Related standards

• ISO 18526 (test methods series for eye/face protection)
• ISO 16321 (requirements for occupational eye and face protectors)
• ISO 4007 (vocabulary for eye and face protection)
• CSA Z262.6:2014 (facially featured headforms) - referenced for children headforms and sizing.

ISO 18526-4:2020 is essential for anyone needing standardized, anthropometrically grounded headforms to test and certify eye and face protection products.