This standard applies to sliding stem flangeless control valves@ sizes 20 mm (3/4 inch) through 600 mm (24 inches) for Classes 150@ 300@ and 600. The face-to-face dimensions listed apply only to control valves that will be bolted between flanges. This standard is not intended to include rotary valves@ such as butterfly valves. Purpose The purpose of this standard is to aid users in their piping designs for sliding stem flangeless control valves by providing valve face-to-face dimensions without giving special consideration to the equipment manufacturer to be used