ISO 877-1:2025

Overview

ISO 877-1:2025 - Plastics - Methods of exposure to solar radiation - Part 1: General guidance provides high‑level guidance on choosing and using outdoor exposure methods for plastics. It applies to plastics materials, products and product portions and defines how to determine radiant exposure. The document guides selection between direct natural weathering, glass‑filtered exposure and intensified solar exposure (covered in ISO 877-2:2025 and ISO 877-3), and explains measurement, monitoring and reporting best practices. Note: black‑box (high‑temperature) exposures are excluded (see ASTM G7 / ASTM D4141).

Key topics and technical requirements

• Principle of testing: expose specimens to natural solar radiation (direct or glass‑filtered) or intensified solar radiation and evaluate changes (colour, optical, mechanical, etc.) after defined exposure stages.
• Radiant exposure measurement: instrumental measurement and integration of irradiance to obtain total or UV radiant exposure is preferred; results expressed in terms of radiant exposure reduce seasonal and location variability.
• Apparatus and instruments: general apparatus requirements and instruments for measuring radiant exposure and other climatic factors are specified; monitoring of specimen temperature, moisture and irradiance is recommended.
• Specimen preparation and conditioning: requirements for form, number, conditioning and storage of test specimens prior to exposure.
• Exposure conditions and stages: classification of climates, exposure orientations (e.g., vertical vs near‑horizontal), types of exposure and duration criteria; exposure stages may be defined by time or by specified radiant exposure.
• Procedure and mounting: guidance on mounting test and reference specimens, making climatic observations and determining property changes.
• Results and reporting: how to express changes in properties, exposure levels, climatic conditions and required content of the test report; Annex A provides a climate classification framework.

Practical applications and intended users

ISO 877-1:2025 is intended for:

• Materials scientists and polymer formulators assessing outdoor durability.
• Test laboratories and certification bodies performing natural weathering or concentrated solar tests.
• Manufacturers, product designers and procurement teams validating plastics for outdoor use (building facades, automotive trim, outdoor furniture, signage, coatings).
• R&D teams evaluating additives, stabilizers, coatings and comparative performance.

Use cases include material selection, product qualification, life‑expectancy estimation, benchmarking and correlation with accelerated tests (ISO 877-3).

Related standards

• ISO 877-2:2025 (direct and glass‑filtered weathering)
• ISO 877-3 (concentrated solar radiation)
• ISO 9370 (radiant exposure measurement)
• ISO 4582, ISO 4892-1, ISO 2818, ISO 10640, ISO 291, ISO 472
• ASTM G7, ASTM D4141, ASTM G179, ASTM G183

Keywords: ISO 877-1:2025, plastics, solar radiation, natural weathering, radiant exposure, outdoor exposure, weathering tests, test methods.