ISO 877-3:2018

Overview

ISO 877-3:2018 - "Plastics - Methods of exposure to solar radiation - Part 3: Intensified weathering using concentrated solar radiation" specifies a standardized method for accelerated outdoor weathering of plastics using reflecting concentrators (often described as Fresnel reflectors) to concentrate natural sunlight. The standard defines how to expose specimens to intensified solar radiation, monitor exposures, control specimen temperature, and report property changes after defined exposure stages.

Key Topics and Requirements

• Purpose: Assess property changes in plastics produced by accelerated, concentrated solar exposure.
• Apparatus: Use of solar concentrating devices with single- or dual-axis tracking and mirror arrays; schematic configurations are described. Measurement of climatic factors and irradiance in the exposure area is required.
• Exposure site: Best suited to locations receiving at least 3 500 hours of sunshine per year and average daytime relative humidity below 30%; where the ratio of direct to global normal solar radiation is typically ≥ 0.75.
• Orientation and operation: Mirror orientation and concentrator operation follow guidance referenced from ASTM G90.
• Temperature control: Specimens are cooled by blowers; typical specimen temperatures are about 10 °C higher than for non-concentrated direct sunlight. Optional active temperature control methods (black/white panel or sensor-based) are described; note of a patent declaration related to temperature control (Atlas Material Testing Technology LLC).
• Exposure staging and measurement: Defines exposure stages by solar radiant exposure and provides guidance on selecting stages and instrumentally measuring solar radiant exposure.
• Test procedure and reporting: Specifies specimen mounting, climatic observations (temperature, RH, precipitation, time of wetness), expression of results, and required contents of the test report.

Applications and Who Uses It

ISO 877-3:2018 is used by:

• Materials and polymer testing laboratories performing accelerated outdoor weathering tests
• Polymer and additives manufacturers evaluating UV/stability performance
• Product developers and quality engineers assessing long-term outdoor durability (e.g., exterior plastics, coatings, automotive trim)
• Certification bodies and standards organizations requiring reproducible concentrated-sunlight exposure data

Practical benefits include faster discrimination between materials, realistic outdoor degradation mechanisms (when site criteria are met), and standardized reporting for regulatory or comparative studies.

Related Standards

• ISO 877-1 - General guidance for exposure to solar radiation
• ISO 877-2 - Direct weathering and exposure behind window glass
• ISO 4892-1 - Laboratory light source exposure (general)
• ASTM G90 - Practice for concentrated natural sunlight weathering (referenced for concentrator and site requirements)
• ASTM G179 - Black/white panel temperature devices for natural weathering

Keywords: ISO 877-3:2018, plastics, concentrated solar radiation, Fresnel reflectors, accelerated weathering, solar concentrating devices, ASTM G90.