Proposed Energy Standard for Data Centers, Telecommunications Buildings Open for Public Comment

March 18, 2015
Proposed ASHRAE Standard 90.4P, Energy Standard for Data Centers and Telecommunications Buildings, is open for public review—its first—until March 30, 2015.

Proposed ASHRAE Standard 90.4P, Energy Standard for Data Centers and Telecommunications Buildings, is open for public review—its first—until March 30, 2015.

“The proposed standard is intended to work in concert with ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings,” Ron Jarnagin, chair of the Standard 90.4 committee, said. “There is no intent to duplicate what is contained in Standard 90.1, but, rather, we are proposing criteria to support the specialized nature of the larger data centers. When adopted, design and construction of data centers will require the use of both standards 90.1 and 90.4 for compliance with building codes.”

David Quirk, chair of ASHRAE Technical Committee 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment, noted the intent of Standard 90.4P is to create a performance-based approach that would be more flexible and accommodating of innovative change, which can occur rapidly in data-center design, construction, and operation.

Data-center applications are unlike their commercial-building counterparts in two significant ways, Quirk noted. First, they include significantly higher plug loads. Second, they employ rapidly changing technology for information-technology equipment and associated power/cooling approaches.

“It has been acknowledged that these differences drive a fundamentally different approach to regulating minimum efficiency requirements for the electrical and mechanical systems that support the plug loads,” Quirk said. “By using an approach that requires compliance to a ‘system’ level of performance, designers and end-users can utilize various tradeoffs in their optimization strategies, depending on their company-specific business models.”

There is recognition that current industry modeling tools do not possess all of the necessary mathematical models to accurately and appropriately model data-center HVAC and power design, Jarnagin said.

The standard is based on the principles of power-use effectiveness (PUE) as defined by The Green Grid. Because PUE is an operational-measurement metric, and this is a design standard, however, use of PUE terminology is not technically accurate. The committee recognizes language needs to be developed to relate the calculations of energy efficiency set forth in this standard to a total efficiency number, as well as to allow tradeoffs between electrical and mechanical elements. Suggestions from reviewers as to how best to accomplish this are welcome, Jarnagin said.

Jarnagin said the 90.4P and 90.1 committees are aware of potential conflicts between the definitions of computer rooms and data centers in the standards. The intent is to address those conflicts once Standard 90.4 is approved and published.

The proposed standard applies to new data centers and telecommunications buildings and their systems, new additions to data centers and telecommunications buildings and their systems, and modifications to systems and equipment in existing data centers and telecommunications buildings.

To read the draft standard and to comment, go to

About the Author

Scott Arnold | Executive Editor

Described by a colleague as "a cyborg ... requir(ing) virtually no sleep, no time off, and bland nourishment that can be consumed while at his desk" who was sent "back from the future not to terminate anyone, but with the prime directive 'to edit dry technical copy' in order to save the world at a later date," Scott Arnold joined the editorial staff of HPAC Engineering in 1999. Prior to that, he worked as an editor for daily newspapers and a specialty-publications company. He has a bachelor's degree in journalism from Kent State University.