Covers the minimum requirements for centrifugal compressors used in petroleum, chemical, and gas industry services that handle air or gas. Does not apply to fans or blowers that develop less than 34kPa (5 pounds per square inch) pressure rise above atmospheric pressure; these are covered by API Standard 673. This standard also does not apply to packaged, integrally-geared centrifugal air compressors, which are covered by API Standard 672.