Overview
EN ISO 18526-1:2020 - Eye and face protection - Test methods - Part 1: Geometrical optical properties (ISO 18526-1:2020) defines reference test methods for measuring the geometrical optical properties of non‑corrective (plano) lenses used in eye and face protectors. It specifies how to determine spherical, cylindrical and prismatic refractive power of both unmounted and mounted plano lenses, and sets requirements for test conditions and uncertainty of measurement. Alternative test methods are permitted only if shown equivalent and with no greater measurement uncertainty than the reference method.
Key topics and technical requirements
- Scope: Applies to plano lenses for eye and face protection; does not replace product requirement standards that specify other test methods.
- Primary test method: The telescope method for measuring refractive and prismatic power of plano lenses (described in detail, including apparatus and procedure).
- Apparatus guidance: Example telescope setup (nominal aperture ~20 mm, magnification ×10 to ×30, adjustable eyepiece with reticule). Calibration of the telescope must achieve a measurement uncertainty of 0.01 D (dioptre) using the specified calibration procedure.
- Targets and optics: Details on illuminated target patterns and alignment for accurate measurements.
- Environmental and test conditions: Default ambient temperature range 16 °C to 32 °C and relative humidity (50 ± 20) % unless otherwise specified; tests to be performed at defined reference points on the lens.
- Uncertainty of measurement: Each measurement must include an evaluated uncertainty per Annex A and ISO/IEC Guide 98‑3 (GUM).
- Additional methods: Procedures for prism imbalance, spatial deviations and calibration methods are included; test reports and procedural requirements are specified.
Applications and who uses this standard
EN ISO 18526-1:2020 is intended for practical use by:
- PPE manufacturers designing and producing safety goggles, face shields and visors to verify optical quality of plano lenses.
- Testing laboratories and certification bodies performing standardized optical measurements for compliance and certification.
- Product designers and R&D teams assessing lens geometry, prismatic effects and optical uniformity.
- Regulators and procurement specialists specifying accepted test methods in tender or regulatory documents.
This standard supports consistent PPE testing, ensures optical safety and compatibility with occupational eye and face protection requirements, and aids international trade by aligning test methods.
Related standards
- ISO 18526 series (other parts, e.g., Part 2 / Part 4)
- ISO 16321 (requirements for occupational eye and face protectors)
- ISO 4007 (vocabulary for eye and face protection)
- ISO/IEC Guide 98‑3 (GUM: uncertainty of measurement)
Keywords: EN ISO 18526-1:2020, eye and face protection, geometrical optical properties, refractive power, prismatic power, plano lenses, test methods, PPE testing, optical safety standards.
