This standard specifies a test method primarily used to assess the color fastness to hot water of wool and wool-containing textiles. The test specimen is wound together with a standard adjacent fabric onto a glass rod, treated with slightly acidified hot water, and subsequently dried. After completion of the test, the degree of color change of the specimen itself and the degree of staining on the adjacent fabric are evaluated by comparing them with standard grey scales, thereby assessing the color durability of the textile in hot water environments. Conducting this test typically requires a water bath apparatus capable of providing specific temperature and environmental conditions.