1.1 This specification covers hot-dipped galvanized welded steel pipe in sizes ranging from 1.315–8.625 in. (33.4 – 219.1 mm) outside diameter (OD) inclusive, with nomi This specification covers hot-dipped zinc-coated (galvanized) welded steel pipe in NPS 1, NPS 1 ¼, NPS 1 ½, NPS 2, NPS 2 ½, NPS 3, NPS3