Air-Conditioning, Heating and Refrigeration Institute (AHRI). 2004. This standard supersedes ARI Standard 540-99.16p. This standard applies to electric motor driven, single and variable capacity positive displacement refrigerant compressors and compressor units. This standard also applies to the presentation of performance data for positive displacement refrigerant compressors and compressor units for air-cooled, evaporatively-cooled or water-cooled air-conditioning, heat pump and refrigeration applications