SCI Ductile Iron Pipe Fittings conform to ASME B16.3 dimensions. Bushings and couplings conform to ASM B16.14. The threads are NPT per ANSI/ASME B1.20.1. Ductile iron is ASTM A536 Class 65-45-12. All SCI Ductile Iron Fittings are UL & ULC Listed and FM Approved.