The General Standards Committee of the Air-Conditioning and
Refrigeration Institute (ARI, Arlington, VA) has approved and released an addendum to ARI
Standard 550/590-1998 "Standard for Water Chilling Packages Using the Vapor
Compression Cycle." Standard 550/590-98 combines two previously separate standards: ARI Standard
550-92, "Centrifugal and Rotary Screw Water Chilling Packages," and ARI
Standard 590-92, "Positive Displacement Compressor Water Chilling Packages." The standard and addendum can be downloaded for free at www.ari.org.