Specimens are mounted directly onto a solid substrate (like plywood or insulation board). This simulates materials used in roofing or automotive interiors where heat is trapped behind the material, driving up the specimen's temperature. Benchmark Weathering Climates

of materials like plastics, coatings, and textiles to the environment. Unlike accelerated laboratory tests, this standard focuses on exposure to natural sunlight, moisture, and temperature. Atlas Weathering Services 📋 Key Standard Requirements Direct Exposure

Simulates higher heat-retention scenarios like building sidings.

Natural weathering is complex. While accelerated weathering devices (like xenon arc or fluorescent UV) provide faster results, provides the "real-world" validation that these accelerated tests aim to simulate.

While accelerated laboratory testing (like ASTM G154 or G155) is faster, ASTM G7 remains the "gold standard." There is no substitute for the complex interaction of heat, humidity, and the full spectrum of natural sunlight. Many industries use ASTM G7 data to validate the results they see in their accelerated weathering chambers. How to Get the Document