GB/T 18631-2002

GB/T 18631-2002 specifies the requirements for north sky daylighting in textile fibre classing rooms, ensuring consistent and standardized lighting conditions for visual colour grading and quality assessment of raw textile fibres. This standard is applied in textile industry laboratories and grading facilities where natural daylight from the north sky is used to evaluate fibre colour, lustre, and other visual characteristics. It provides guidelines for window design, light diffusion, and room layout to minimize shadows and glare, enabling accurate and repeatable fibre classification.