Overview
ISO 2810:2020 - Paints and varnishes - Natural weathering of coatings - Exposure and assessment - defines how to plan, carry out and report natural weathering tests for coatings. The standard covers selection of exposure type (direct outdoor exposure or weathering behind window glass), environmental and procedural parameters that influence durability, and the measurement and recording of climatic factors and solar radiation. Note: ISO 2810:2020 excludes special atmospheric influences such as industrial pollution.
Key topics and requirements
- Scope and purpose: Determine resistance of coatings to solar radiation and atmospheric exposure using natural weathering; results apply specifically to the environment tested.
- Exposure strategy: Choose site (marine, rural, temperate, etc.), rack height, orientation and tilt to match intended end use. Racks normally face the equator; common tilt angles include 45°, 5° (automotive/roofing) or vertical (walls). Panels should be ≥0.45 m above ground.
- Exposure duration: Recommended minimum exposure period is one year (or multiples); reproducibility improves if exposure starts at the same time of year (preferably spring). Alternative endpoint definitions use a specified degree of degradation or radiant exposure (dosage) integrated over time.
- Climate and radiation measurement: Monitor and report air temperature, surface temperature, relative humidity, rainfall, time of wetness and sunshine hours. Use calibrated radiometers:
- Pyranometers (WMO second-class minimum; annual calibration traceable to WRR) for total irradiance.
- Pyrheliometers (WMO first-class minimum; annual calibration traceable to WRR) for direct beam irradiance.
- Total-UV and narrow-band UV radiometers with appropriate passbands and cosine correction; follow calibration guidance.
- Specimen preparation and racks: Use standard test panels and mounting that avoid mechanical stress and cross-drainage. Consider masked/covered areas and simulated backing (e.g., “black box” or insulation) where relevant.
- Reporting and references: Full climatic records, test parameters and any washing/polishing during exposure must be included in the test report. Normative references include ISO 1514, ISO 2808, ISO 4618 and WMO Publication No. 8.
Applications and users
ISO 2810:2020 is used by:
- Coatings and paint manufacturers for product development and durability claims
- Independent test laboratories and QA/QC facilities for comparative testing
- Specifiers, architects and façade/roofing designers assessing long-term performance
- Automotive and building product developers for glass-filtered or direct exposure tests
- Certification bodies and regulatory officials evaluating weathering resistance
Keywords: ISO 2810:2020, natural weathering, coatings durability, paints and varnishes, exposure racks, solar radiation measurement, pyranometer, pyrheliometer, radiant exposure, weathering behind glass.
Related standards
- ISO 1514, ISO 2808, ISO 4618 (referenced normative documents)
- WMO Publication No. 8 (radiometric instrument classes)
- ISO 877-1:2009 (climate classification referenced in Annex B)
- Relevant industry practices such as ASTM/GUIDES and EN standards (e.g., EN 13523-19) for specialized applications.
