Ashrae 904 Pdf Upd May 2026

The ANSI/ASHRAE Standard 90.4, established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, serves as the primary energy efficiency standard for data center design and operation. As of early 2026, the standard is transitioning from the widely adopted 2022 edition to the newly released 2025 edition, which expands its focus from pure energy efficiency to broader sustainability goals. Core Purpose and Scope

: Designers can now achieve compliance without a traditional economizer by following the ASHRAE TC 9.9 Thermal Guidelines (5th Edition). ashrae 904 pdf upd

Expanded Sustainability Scope: The 90.4-2025 edition shifts from just energy efficiency to a holistic view of environmental impact, now specifically regulating greenhouse gas emissions and water consumption. The ANSI/ASHRAE Standard 90

This article explores the key provisions, technical updates, and compliance pathways in the 2022 version of ASHRAE 90.4 — a document often mistakenly referred to as "ASHRAE 904." They drop the decimal point mentally (90

• They drop the decimal point mentally (90.4 → 904)
• ASHRAE’s numbering system includes 90.1, 90.2, 90.4 – no 904 exists
• Search autocomplete sometimes corrects “90.4” to “904”

Official Standard: You can purchase the full Standard 90.4-2022 from the ASHRAE Bookstore.

• Maximum allowable IT equipment load (ITE load)
• Maximum allowable cooling power
• Maximum allowable fans & auxiliary power
• Compliance paths: Prescriptive or Performance-based (Energy Recovery Efficiency – ERE)