Electric-Fusion (Arc)-Welded Steel Pipe (NPS 4 and Over) to ASTM A 139 Standard
A 139 specification covers five grades of electric-fusion (arc)-welded
straight-seam or helical-seam steel pipe. Pipes are manufactured in
nominal diameters of 4 inches and larger with nominal (average) wall
thickness of 1.0 in. [25.4 mm] and less.
A 319 pipes are intended for conveying liquid, gas and vapour.