HDPE ground protection boards 1/2 Inch for architecture-HDPE 10.2.1.1 Fittings manufactured in accordance with Table 10.2.1.1 shall be permitted to be used. [24:Table 10.2.1.1] Table 10.2.1.1 Fittings Materials and Dimensions Materials and Dimensions Standard Cast Iron Gray Iron Threaded Fittings, Classes 125 and 250 ASME B16.4 Gray Iron Pipe