Atlanta, Georgia: ASHRAE has announced publishing a new performance-based standard for data centres that establishes the minimum energy efficiency requirements of data centres for design and construction, for creation of a plan for operation and maintenance (O&M) and for utilisation of on-site or off-site renewable energy resources.

ANSI/ASHRAE Standard 90.4-2016, Energy Standard for Data Centers, the announcement said, offers the design components for mechanical load (MLC) and electrical loss (ELC). Calculations of the MLC and ELC, the announcement explained, are made and then compared to the maximum allowable values shown in the standard based on climate zones. The announcement mentioned that compliance with Standard 90.4 is achieved when the calculated values do not exceed the values contained in the standard. It added that an alternative compliance path is provided that allows trade-offs between the MLC and ELC.

“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,” said, Ron Jarnagin, Chair of the 90.4 committee. “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 IT technology make data centre applications significantly different from their commercial building counterparts. He added: “The committee initially pursued a Green Grid power use effectiveness-like (PUE) 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. 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.”

According to the Society, the Standards Committee, which has oversight of all ASHRAE standards, will work together 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 centres from Standard 90.1. Standard 90.4 already refers users to Standard 90.1 for requirements on lighting, service water heating and the building envelope, it added.

A sample compliance checklist, diagrams to illustrate compliance and sample calculations are included in the standard, said the Society.

ASHRAE said that further details, such cost and to purchase, are available on its website.