Overview
EN ISO 16474-2:2013 (ISO 16474-2:2013) defines standardized laboratory methods for exposing paints, varnishes and similar materials to xenon‑arc lamps to reproduce weathering effects caused by daylight (including daylight filtered through window glass). The standard specifies controlled exposure to filtered xenon‑arc light in the presence of moisture, with measurement of light dose and environmental parameters to enable reproducible, accelerated weathering tests.
Key topics and technical requirements
- Purpose: Simulate spectral power distribution of natural daylight (UV + visible) using xenon‑arc lamps fitted with appropriate filters.
- Controlled conditions: Specify and control irradiance, radiant exposure, temperature, relative humidity and wetting to replicate end‑use environments.
- Wetting methods: Spray, immersion or condensation as means to introduce moisture during exposure.
- Filters and lamp selection: Use various xenon lamp types and filter combinations to match test requirements (e.g., unfiltered daylight or daylight through glass).
- Measurement and instrumentation:
- Radiometers and procedures to measure irradiance and calculate radiant exposure in the plane of the specimens.
- Use of black‑standard / black‑panel thermometers to monitor specimen surface temperature.
- Exposure cycles: Definition of light/dark cycles, spray cycles and dark period options; annexes provide additional cycle examples.
- Specimen handling: Mounting, exposure duration, and post‑exposure property assessments. (Note: specimen preparation and specific evaluation methods are covered in other standards.)
- Intercomparability caveat: Results from different equipment should only be intercompared if an appropriate statistical relationship has been established for the material under test.
Applications and who uses it
- Accelerated weathering testing for:
- Coatings durability (color, gloss, chalking, cracking, adhesion)
- Material selection and product development
- Quality control and batch consistency
- Comparative performance claims and R&D
- Typical users:
- Paints and varnishes manufacturers and formulators
- Independent test laboratories and certification bodies
- Automotive, architectural and consumer goods manufacturers
- Material scientists and polymer/plastics testing labs
Related standards
- ISO 16474-1 - General guidance for laboratory light source exposures
- ISO 4892-2 - Xenon‑arc exposures for plastics
- ISO 4618 - Terms and definitions for paints and varnishes
- ISO 9370 - Instrumental determination of radiant exposure in weathering tests
- Supersedes: EN ISO 11341:2004 (technical revision)
This standard is essential for consistent, reproducible xenon‑arc accelerated weathering tests and for ensuring test results are meaningful for real‑world daylight exposure scenarios. Keywords: xenon‑arc lamps, accelerated weathering, paints and varnishes, radiant exposure, irradiance, laboratory light sources, ISO 16474-2.
