Quality testing of PVC-coated steel roofing tiles primarily focuses on impact resistance, weather resistance, and resistance to aging. Impact resistance is assessed by striking the tiles with a steel ball or by listening to the sound they make upon impact; high-quality tiles produce a crisp sound. Weather resistance and resistance to aging are evaluated by observing fading and chalking after exposure to direct sunlight outdoors, or by wiping the surface with an alcohol-soaked cotton swab to check for color loss; high-quality tiles have a fine, uniform cross-section. These indicators are directly related to service life and safety...
