Not withstanding 4-6-2/5.1.1 or 4-6-2/5.1.2, the minimum wall thickness of pipes is not to be less than that indicated in 4-6-2/Table 4 for steel pipes, and 4-6-2/Tables 5A and 5B for other metal pipes. The wall thicknesses listed in these tables are nominal wall thicknesses. When using the tables, no allowances need be made to account for negative tolerance or reduction in thickness due to bending.