API STD 599:2013 covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination,inspection, and test requirements for metallic plug valves as follows.
— Steel, nickel base, and other alloy plug valves with flanged or butt-welding ends and ductile iron plug valves with flanged ends in sizes 15 ≤ DN ≤ 600 ( 1 / 2 ≤ NPS ≤ 24).
— Threaded or socket-welding ends for sizes 15 ≤ DN ≤ 50 ( 1 / 2 ≤ NPS ≤ 2). Valve bodies conforming to ASME B16.34 may have one flange and one butt-welding end, or one threaded and one socket-welding end.
— Lubricated and nonlubricated valves that have two-way coaxial ports. Three-way and four-way plug valves do not fall under the scope of this standard.
— Tandem plug valves which have two independent operating plugs in a single body.
