This standard now covers the minimum requirements for axial compressors, integrally geared process centrifugal compressors and expander-compressors, as well as single shaft centrifugal compressors for use in the petroleum, chemical, and gas industries services that handle air or gas.This standard does not apply to fans (covered by API 673) or blowers that develop less than 34 kPa (5 psi) pressure rise above atmospheric pressure. This standard also does not apply to packaged, integrally-geared centrifugal plant and instrument air compressors, which are covered by API Std 672. Hot gas expanders over 300 C (570 F) are not covered in this standard.