Overview
ISO 877-2:2025 - "Plastics - Methods of exposure to solar radiation - Part 2: Direct weathering and exposure behind window glass" describes two outdoor test methods for assessing how solar radiation affects plastics. It defines Method A (direct exposure) and Method B (glass‑filtered exposure, i.e. behind window glass) to evaluate property changes after specified exposure stages. The document supplements general guidance given in ISO 877-1:2025.
Key topics and technical requirements
- Two exposure methods
- Method A: direct weathering in the open atmosphere.
- Method B: exposure behind a glass cover to simulate glass‑filtered solar radiation.
- Test fixtures and racks
- Racks must allow the desired tilt, keep specimens at least 0.5 m from ground/obstructions, and permit free shrinkage/warping.
- Under‑glass fixture: open‑bottomed box with framed glass cover, minimum 75 mm ventilation gap to specimens.
- Glass cover guidance (Method B)
- Flat, transparent, non‑laminated window glass; thickness 2.0–3.2 mm (preferably 3.0–3.2 mm).
- Glass pre‑age for about 3 months to reduce UV transmission variability (see ASTM G24 guidance).
- Monitor transmission at 320 nm; replace glass when transmission falls to ≤80% of initial, or at least every 5 years if not measured.
- Radiometry and climatic measurement
- Radiometers positioned 75 mm ± 5 mm behind glass, parallel within ±2° to cover each rack.
- Radiant exposure measurement, climatic observations, and documented exposure stages (duration and solar radiant exposure) are specified.
- Exposure orientation
- Tilt angle fixed, facing the equator; selectable 0°–90° (commonly 5° or 45° for plastics).
- Reporting
- Procedures for mounting, exposure, property determination, expression of results and test reporting are specified (see Clauses 9–11).
Applications and users
ISO 877-2:2025 is used to simulate real‑world solar weathering effects on plastics to support:
- Product development and material selection (automotive, building façade, glazing, consumer goods)
- Quality control and durability claims
- Comparative performance testing for coatings, polymers, composites and additives
- Regulatory compliance and procurement specifications
Typical users: materials scientists, R&D engineers, test laboratories, manufacturers of plastics and glazing, standards bodies and certification organizations.
Related standards
- ISO 877-1:2025 - Plastics - Methods of exposure to solar radiation - Part 1: General guidance
- ASTM G24 - Guidance on glass pre‑ageing, maintenance and lifetime (referenced for Method B)
Keywords: ISO 877-2:2025, plastics, solar radiation exposure, direct weathering, window glass exposure, glass‑filtered solar radiation, radiometer, UV transmission, test fixtures, outdoor weathering.
Open preview (PDF)Plastics — Methods of exposure to solar radiation — Part 2: Direct weathering and exposure behind window glass
