scope:

This standard covers the minimum requirements for special-purpose, enclosed, precision involute gear single- and double-helical one- and two-stage speed increasers and reducers of parallel-shaft design for use in petroleum, chemical, and gas industry services. This standard is intended for gear units that are in continuous service without installed spare equipment. Gear sets furnished to this standard are considered matched sets.

NOTE The purchase of a spare set of gear rotors or a complete gear unit does not mean that the gear unit in continuous service has an installed spare.

This standard includes related lubricating systems, controls, instrumentation, and other auxiliary equipment. This standard is not intended to apply to gear units in general-purpose service, which are covered by API 677; to gears integral with other equipment, such as integrally geared compressors and expanders covered by API 617 or API 672; or to gears other than involute helical.