ANSI/ASHRAE Standard 90.4 offers a framework for the energy-efficient design of data centers, with special consideration given to their unique load requirements as compared to other buildings. Standard 90.4 was developed under the guiding principle that data centers are mission-critical facilities, and careful attention must be paid to the potential impacts made by the standard’s requirements. This philosophy continues to guide successive editions, while acknowledging energy-efficiency breakthroughs in the industry.

The newly revised 2022 edition of the standard arrives with significant changes:

• Additional options for mechanical load component calculations
• A further reduction to the maximum ELC values required for compliance
• The elimination of incoming service segment from ELC calculation in recognition that designers must already account for public utility transformers and feeders in most projects
• New ELC segment calculation breakpoints of 25%, 50%, 75%, and 100% design load to make ELC and MLC congruent
• A new methodology for applying a credit to combined MLC and ELC for the deployment of onsite renewable energy
• Specific language to give credit for recovered heat shared with non-data-center spaces