This standard is applicable to the surface state of products manufactured with materials and methods that can ensure, under normal conditions, the following limits of the numerical values of the parameters: 0.008 um ≤ Ra ≤ 400 /xm 0.025 pim ≤ Rz and Ry ≤ 1 600 txm 0.002 mm ≤ S and Sm ≤ 12.5 m This standard establishes the list of parameters, the types of direction of surface irregularities and gives general rules for determining surface roughness. NOTE — In particular cases, it is allowed to use other parameters than those specified in this standard, but they must be, for each case, clearly defined. This standard is not applicable to surfaces whose characteristics make it impossible to measure surface roughness by the methods generally used.