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2019 Update to Standard 90.4

ASHRAE’s Data Centers Standard Updated to Align with Industry’s Evolving Technologies


ANSI/ASHRAE Standard 90.4-2019, Energy Standard for Data Centers

From HVAC&R Industry Newsletter, Dec. 5, 2019

ASHRAE’s newly updated data centers energy standard includes a reduction of the maximum mechanical load component (MLC) and electrical loss component (ELC) for compliance in order to evolve with the IT industry’s constantly changing technologies.

ANSI/ASHRAE Standard 90.4-2019, Energy Standard for Data Centers was published yesterday and is the second version of the standard that establishes the minimum energy efficiency requirements for the design and operation of data centers. The 2019 version includes two key updates. The updated standard includes:

  • a reduction of the maximum MLC values required for compliance. The standard also removes the design MLC compliance path in favor of a more accurate maximum annualized MLC calculation.
  • a reduction of the maximum ELC values for the UPS segment required for compliance. This change was made to recognize improvements in the efficiency of core electrical distribution equipment.

The changes better align with the industry’s evolving uninterruptible power supply (UPS) technology, said Richard Zbin, Life Member ASHRAE, HFDP, chair of SSPC 90.4.

“The designers will need to adhere to the lowered MLC values and create two distinct values for each climate zone based on room size,” he said.

Standard 90.4 offers a framework for the energy efficient design of data centers with special consideration to their unique load requirements compared to other buildings. The standard was developed under the guiding principle that data centers are mission critical facilities demanding careful attention to the potential impact of its requirements. This year, ANSI/ASHRAE/IES Standard 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings, referenced Standard 90.4 as an alternative compliance path for large computer rooms such as data centers.

Standard 90.4 is under continuous maintenance to ensure the standards keeps pace with the ever-changing nature of IT, according to Zbin. The 2019 version of the standard incorporates six addenda from the 2016 edition, and some changes better align Standard 90.4 with Standard 90.1.

“The industry on its own is driving towards better efficiencies and Standard 90.4 is working with designers and manufacturers to ensure the standard does not inhibit innovation but drives the industry towards energy efficiencies,” said Zbin. “The industry and others are starting to embrace this standard. To give an example, the State of Washington has adopted a portion of Standard 90.4, which will become law on July 1, 2020. The (90.4) committee has also been notified that a few owners have adopted this standard in their design requirements for their corporate designs.”

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