Alcance
                            This document specifies the requirements for a heavy-duty series of bolted bonnet steel gate valves for petroleum refinery and related applications where corrosion, erosion and other service conditions can indicate a need for full port openings, heavy wall sections and large stem diameters.This document sets forth the requirements for the following gate valve features:—     bolted bonnet;—     outside screw and yoke;—     rising stems;—     non-rising handwheels;—     single or double gate;—     wedge or parallel seating;—     metallic seating surfaces;—     flanged or butt-welding ends.It covers valves of the nominal sizes DN:—     25; 32; 40; 50; 65; 80; 100; 150; 200; 250; 300; 350; 400; 450; 500; 600;corresponding to nominal pipe sizes NPS:—     1; 1�; 1�; 2; 2�; 3; 4; 6; 8; 10; 12; 14; 16; 18; 20; 24;applies for pressure Class designations:—     150; 300; 600; 900; 1 500; 2 500;and applies for pressure PN designations:—     16, 25, 40, 63, 100, 160, 250 and 400.