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 [DN 6 to DN 500] 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) and DN [diameter nominal] has been substituted in this standard for such traditional terms as nominal diameter, size, and nominal size.