ASTM A139 covers five grades of electric -fusion (arc)-welded straight-seam or spiral-seam steel pipe in NPS 4 to 92 inclusive with nominal (average) wall thick-dimensions may be furnished provided such pipe complies with all other requirements of this specification. The grades of steel are pipe mill grades having mechanical properties which differ from standard plate grades, The pipe is intended for conveying liquid , gas, or vapor.

The dimensionless designator NPS nominal pipe size has been substituted in this standard for such traditional terms as "nominal diameter," "size," and "nominal size." A comprehensive listing of standardized pipe dimensions is contained in ANSI B36.10. The suitability of pipe for various purposes is dependent on its dimensions, properties, and conditions of service.

Pipe having other dimensions may be furnished provided such pipe complies with all other requirements of this specification and the grades of steel of the manufactured pipes. The pipe is intended for conveying liquid, gas, or vapor. The values stated in inch-pound units are to be regarded as the standard.

Defects in the welds, such as sweats or leaks, shall be repaired or the piece rejected at the option of the manufacturer. Repairs of this nature shall be made by completely removing the defect, cleaning the cavity, and then welding. All repaired pipe shall be subject to hydrostatic testing.

JIS Number and Corrensponding Foreign Standard