ASHRAE Standard 127 establish a uniform set of test requirements for rating both existing and emerging cooling technologies that support DC and ITE systems. Regulatory agencies and industry advocates control precise efficiency ratings and performance requirements for identified product types. These requirements evolve with time and magnitude of installed base. This document serves to provide overarching test methodologies for DC and ITE cooling technologies, regardless of their state of adoption, to support rapid product evolution.Changes in the 2020 edition include modification of title, purpose, and scope (TPS), as well as extensive changes to Section 3, “Definitions, Section 4, “Classification,” and Section 5, “Rating Requirements.” Revisions include the addition of new cooling types (e.g., row-based cooling, rear rack door heat exchanger, and others). Substantial effort was given to Normative Appendix E, which provides illustrations of additional types of cooling technologies now included within the scope of this standard.