1.1 This specification covers black or galvanized welded or seamless threaded steel couplings for use with steel pipe in NPS 1/8 to NPS 20 inclusive (Note 1). Couplings ordered under this specification are intended for the uses outlined in the pipe specifications referencing this specification.

Note 1—The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as nominal diameter, size, and nominal size.

1.2 The values stated in inch-pound units are to be regarded as standard. The metric values may be approximate.