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Energy Standard for Data Centers Published by ASHRAE

Sept. 13, 2016
ANSI/ASHRAE Standard 90.4-2016, Energy Standard for Data Centers, is performance-based, offering the design components for mechanical load and electrical loss.

ASHRAE today announced the publication of ANSI/ASHRAE Standard 90.4-2016, Energy Standard for Data Centers.

“We worked very hard to craft this standard in a manner that does not stifle innovation in the data-center industry while simultaneously offering criteria to help ensure energy savings,” Ron Jarnagin, chair of the 90.4 committee, said. “It is important to keep in mind that data centers are mission-critical facilities where risk management is the primary concern.”

Jarnagin noted that high plug loads and rapidly advancing information technology make data-center applications significantly different from their commercial-building counterparts.

Standard 90.4 is a performance-based design standard offering the design components for mechanical load and electrical loss. Calculations of mechanical load and electrical loss are made and then compared to the maximum allowable values shown in the standard. Compliance with Standard 90.4 is achieved when calculated values do not exceed the values contained in the standard. An alternative compliance path allowing tradeoffs between mechanical load and electrical loss is provided.

“The committee initially pursued a Green Grid power-use-effectiveness- (PUE-) like process for setting the criteria in the standard, but the Green Grid’s PUE metric is actually based on measured energy-use data, rather than design-criteria calculations,” Jarnagin said. “We realized that the design calculations contained in Standard 90.4 would not likely match up with the actual energy-use data, so this approach was amended. We feel that we’ve recommended the requirements for 90.4 based on a justifiable 80/20 rule where only the lower-performing systems will be affected.”

The Standards Committee, which has oversight of all ASHRAE standards, will work with the chairs of Standard 90.4 and ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, to remove data centers from Standard 90.1. Standard 90.4 already refers users to Standard 90.1 for requirements on lighting, service water heating, and building envelope.

Standard 90.4 includes:

  • A sample compliance checklist.
  • Diagrams to illustrate compliance.
  • Sample calculations.

The standard is under a continuous-maintenance process, which will allow for changes as needed to keep pace with the rapidly changing technologies in the industry, Jarnagin said.

The cost of Standard 90.4-2016 is $89 for ASHRAE members and $105 for non-members. Copies can be ordered by phone at 1-800-527-4723 (United States and Canada) or 404-636-8400, by fax at 678-539-2129, or online at