Here Pipe and unit indication guide the wall thickness of pipe /pipe fittings ,In simple words how thick the pipe is given by schedule , According to Asme standard For butt weld fittings B16.9 std gives you schedule. Pipe class refers to the material specifications of pipe ,it gives you the grade of pipe. including copper chain, red copper 1mm thickness , size of tags must have 50mm or 45mm for more details download this file .
