The International Organization for Standardization (ISO). Second edition, 2004-07-15. This second edition cancels and replaces the first edition (ISO 10434:1998), which has been technically revised. 40 p. This International Standard 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 would indicate a need for full port openings, heavy wall sections and large stem diameters.