This International Standard specifies requirements for centrifugal pumps, including pumps running in reverse as hydraulic power recovery turbines, for use in petroleum, petrochemical, and gas industry process services. It does not cover sealless pumps. This International Standard is applicable to overhung pumps, between-bearings pumps, and vertically-suspended pumps (see Table 1). Clause 8 applies to specific types of pumps. All other clauses of this International Standard apply to all pump types. The figures in 4.1 show the various specific pump types and the designations assigned to each specific type.