ATLANTA - Since the publication of itsThermal Guidelines for Data Processing Environmentsin 2004, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) said there has been a continued focus on providing guidance to data center operators regarding how to best maintain high reliability while operating their facilities in the most energy efficient manner.

In a new whitepaper, “2011 Thermal Guidelines for Data Processing Environments – Expanded Data Center Classes and Usage Guidance,” published by ASHRAE Technical Committee (TC) 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment, a roadmap has been outlined to facilitate a significant increase in the operational hours during which economizer systems are able to be used, and to increase the opportunity for data centers to become “chillerless,” eliminating mechanical cooling systems entirely, in order to realize improved Power Usage Effectiveness (PUE). The Green Grid created the PUE metric that is widely used to compare the total power to the IT power.

The major change that is introduced in the whitepaper is the addition of two new data center classes. The classes have been added primarily for facilities that are willing to explore the tradeoffs associated with the additional energy saving of the cooling system through increased economizer usage and what that means in terms of the impact to IT equipment attributes such as reliability, internal energy, cost, performance, contamination, etc.

“This whitepaper is truly ground-breaking in that it achieves alignment between representatives of the major IT equipment manufacturers on wider environmental tolerances for IT equipment while providing guidance and a methodology for owners and operators to optimize the operating environment of their data center based on the criteria most important to their business needs,” said Don Beaty, chair of the Publications Subcommittee for TC 9.9. “In order to most quickly meet the current demands of the industry, we are using a two-step approach to introduce this important information sooner rather than later. The information in this whitepaper will be incorporated into the third edition of theThermal Guidelinespublication.”

The whitepaper can be obtained at

Publication date:05/30/2011