ASHRAE continues to widen the temperature and humidity ranges for servers through a soon-to-be-published third edition of the datacom book, “Thermal Guidelines for Data Processing Environments.”
The first edition was published in 2004 and was groundbreaking in that it created the first global, vendor neutral environmental specification for data centers, according to Don Beaty, chair of the Publications Subcommittee of ASHRAE’s Technical Committee (TC) 9.9, Mission Critical Facilities, Technology Spaces and Electronic Equipment. Prior to its publication, data center temperature requirements were set individually by each equipment manufacturer. This typically resulted in using the most stringent temperature plus a safety factor being used across the entirety of the data center.
The approach used by TC 9.9 for the first edition through to the present was to assemble a team of thermal engineers from the major commercial IT manufacturers to develop requirements. The first edition created a recommended temperature upper limit of 77° F (25 C), promoting the use of higher temperatures and endorsed by all of the IT manufacturers.
The second edition (2008) took considerable deliberation amongst the manufacturers and raised the recommended upper limit to 81 F (27 C). Both the first and second editions were groundbreaking (the first edition in unifying the industry and the second edition in enabling the potential to use economizers in many locations and applications), according to Beaty.
The third edition will be equally groundbreaking in that it will enable compressorless cooling (all cooling through economizers) in many applications. Accomplishing this has been a challenge since major tradeoffs (equipment size, equipment cost and operating cost) surface above a certain temperature threshold. This challenge is complicated because the threshold is not the same for all the manufacturers.
“Different locations, applications and business philosophies make it ineffective to force all equipment to be capable of the same high temperature tolerance (in some cases higher thresholds would negatively impact the return on investment),” Beaty said. “To address this, the third edition creates multiple server classes and therefore provides freedom of choice. This is particularly important since the thermal guidelines are used throughout the world.”