This Recommended Practice addresses the special needs of control valve applications in re?nery services. The knowledge and experience of the industry has been captured to provide proven solutions to well-known problems. This document provides recommended criteria for the selection@ speci?cation@ and application of piston and diaphragm- actuated control valves. It also outlines control valve design considerations@ and discusses control valve sizing@ noise@ and fugitive emissions as well as de?ning types of commonly used control valves and their actuators. Recommendations for emergency block and vent valves@ on/off valves intended for emergency isolation or venting@ and special design valves for re?nery services@ such as FCCU slide valves and vapor depressuring systems@ are also included in this Recommended Practice.