ISO 877-2:2025

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.