90.4 Pdf - Ashrae

ASHRAE Standard 90.4-2022 serves as the energy standard for data centers, focusing on specialized metrics like Mechanical Load Component (MLC) and Electrical Loss Component (ELC) rather than traditional PUE. It is frequently updated through a continuous maintenance cycle, with read-only versions and official PDFs available directly through ASHRAE. For more details, visit ASHRAE. Standards and Guidelines - ASHRAE

ASHRAE Standard 90.4, Energy Standard for Data Centers , is a copyrighted document that can be purchased, though free read-only versions of the 2022, 2019, and 2016 editions are available through the ASHRAE website ashrae 90.4 pdf

• Higher operating temperatures: Newer revisions allow data centers to run at 27°C (81°F) or higher, reducing cooling needs.
• Liquid cooling integration: As GPUs and AI racks hit 100 kW+, direct-to-chip and immersion cooling are being integrated into the MLC calculations.
• Carbon metrics: Future versions may include embodied carbon or grid-interactive efficient building (GEB) concepts.

You can download a PDF of ASHRAE 90.4 from the ASHRAE website: ASHRAE Standard 90

Overview

Step 4: Design Electrical Distribution

Sum up the losses from utility feed to the server rack. Include transformer losses, UPS losses (at 50% and 100% load), and PDU losses. If total losses meet the ELC table – you comply. You can download a PDF of ASHRAE 90

Final Verdict: Stop Designing to 90.1

If you are building a new colocation facility or a hyperscale campus, design to 90.4. It is the law of the land in most US jurisdictions (via IECC 2021/2024).

If you are designing a data center for a 10-year lifespan, you should download the current ASHRAE 90.4 PDF but also monitor the standing standard project committee (SSPC 90.4) for public review drafts.