This standard is intended to cover the minimum requirements for centrifugal compressors used in refinery services handling air or gas. It does not cover machines which may be classed as fans or blowers that develop less than 5 pounds per square inch (0.34 bar) from atmospheric pressures or packaged integrally geared centrifugal air compressors@ which are covered by API Standard 672. NOTE: A bullet (e) in the margin indicates where a decision by the purchaser is required. These decisions should be indicated directly on the data sheets when provisions are made for them; otherwise@ they should be stated in the quotation request or in the order.