SPF Ductile Iron Threaded Fittings SPF/MI-1.15 page 1 PS-SUB-3221-v01 20220118 Coupling Fig. 3221 Material Specifications Dimensions: ASME B16.3 Material: ASTM A536 Grade 65-45-12 Finish: Black Threads: NPT per ASME B1.20.1 Agency Approvals: All ductile iron threaded fittings are UL/ULC Listed and FM Approved. Note: Ductile iron fittings have higher tensile strength than that of steel pipe. Therefore, over tightening can cause damage to pipe threads which may cause leakage. Ductile iron fittings should be tightened approximately three turns beyond hand tight, but no more than four turns.
