Overview
ISO 4892-4:2013 - Plastics - Methods of exposure to laboratory light sources - Part 4: Open‑flame carbon‑arc lamps - specifies laboratory methods to reproduce the weathering effects plastics experience in real daylight (or daylight filtered through glass). The standard defines controlled exposure to filtered open‑flame carbon‑arc radiation together with moisture (humidity, spray or condensation), plus requirements for measuring irradiance and reporting results.
Key topics and technical requirements
- Purpose and principle: Expose plastic specimens to glass‑filtered open‑flame carbon‑arc light with controlled heat and moisture to simulate end‑use daylight ageing.
- Apparatus: Details on the open‑flame carbon‑arc light source (carbon rods containing rare‑earth salts and metal coatings), test chambers, radiometers, thermometers, specimen holders and moisture systems.
- Filters and spectral irradiance: Describes three filter types - daylight (type 1), window‑glass (type 2) and extended‑UV (type 3) - and requires spectral irradiance measurement (typically from 250–400 nm in 2 nm increments) to characterise the light reaching specimens.
- Exposure conditions: Defines control of temperature, relative humidity, spray cycles, and light/dark cycling to reproduce various weathering regimes.
- Procedure and measurements: Guidance on specimen mounting, exposure, measurement of radiant exposure and post‑exposure assessment of changes in properties (colour, mechanical properties etc.). Use of a concurrent control material of known behaviour is recommended.
- Intercomparison caution: Results from different apparatus should not be directly compared unless an established statistical relationship exists between devices for the tested material.
- Reporting: Required exposure report elements and references to material‑specific specimen preparation and evaluation standards.
Applications and who uses it
ISO 4892-4 is used for accelerated weathering testing of plastics where open‑flame carbon‑arc radiation is appropriate. Typical users include:
- Test laboratories and certification bodies performing accelerated weathering and durability testing
- Polymer formulators and R&D teams evaluating UV/stress resistance of plastics and coatings
- Quality assurance teams validating material performance for outdoor or sun‑exposed products
- Manufacturers of automotive glazing, building products, outdoor furniture, signage and electrical housings where window‑filtered daylight effects matter
This standard helps predict long‑term colour change, embrittlement, loss of mechanical properties and other weathering phenomena under reproducible laboratory conditions.
Related standards
- ISO 4892‑1 - General guidance on laboratory light source exposure
- ISO 4892‑2 - Xenon‑arc lamps
- ISO 4892‑3 - Fluorescent UV lamps
- ISO 4582 - Determination of changes in colour and variations in properties after exposure
Keywords: ISO 4892-4:2013, open‑flame carbon‑arc, plastics weathering, accelerated weathering testing, spectral irradiance, daylight filters, laboratory light sources.