This International Standard specifies the requirements for a series of compact steel gate, globe and check valves for petroleum and natural gas industry applications. It is applicable to valves of - nominal sizes DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80 and 100, - corresponding to nominal pipe sizes NPS 1/4, 3/8, 1/2, 3/4, 1, 1 1/4, 1 1/2, 2, 2 1/2, 3 and 4, and to pressure designations of Class 150, Class 300, Class 600, Class 800 and Class 1500. Class 800 is not a listed class designation, but is an intermediate class number widely used for socket welding and threaded end compact valves. It includes provisions for the following valve characteristics: - outside screw with rising stems (OS & Y), in sizes 8 <= DN <= 100 and pressure designations 150 <= Class <= 1500 including Class 800; - inside screw with rising stems (ISRS), in sizes 8 <= DN <= 65 and pressure designations of Class <= 800; - socket welding or threaded ends, in sizes 8 <= DN <= 65 and pressure designations of Class 800 and Class 1500; - flanged or butt-welding ends, in sizes 15 <= DN <= 100 and pressure designations of 150 <= Class <= 1500, excluding flanged end Class 800; - bonnet joint construction - bolted, welded, threaded with seal weld, and union nut for nominal pressure rating Class <= 800; - body seat openings; - materials, as specified; - testing and inspection. This International Standard is applicable to valve end flanges in accordance with ASME B16.5 and valve body ends having tapered pipe threads to ISO 7-1 or ASME B1.20.1. It is applicable to extended body construction in sizes 15<= DN <= 50 and pressure designations of Class 800 and Class 1500, and to bellows and bellows assembly construction as may be adaptable to gate or globe valves in sizes 8 <= DN <= 50. It covers bellows stem seal type testing requirements.