Many municipalities and state energy codes adopt ASHRAE 90.4 by reference. For example, Title 24 (California) aligns partially with 90.4. If you are submitting plans for a new data center permit, the building inspector will ask for your MLC/ELC calculations. You cannot do these without the official standard.

The standard requires metering at three points:

Data centers serve as the modern backbone of global commerce, cloud computing, and artificial intelligence. However, their immense computational power demands vast amounts of energy. For years, engineers struggled to apply generalized building energy codes to these highly specialized, mission-critical environments.

ASHRAE 90.4 uses the same climate zones as 90.1 (0 through 8). But unlike 90.1, the MLC allowance varies significantly. You must look up your location in the PDF’s annex tables.

Enter .

Standard 90.4 officially replaced Standard 90.1 for data centre spaces to fix this mismatch. The critical differences include:

PASSED.

If your calculated MLC ≤ the table allowance → You comply. If it exceeds → You must redesign (add economizers, higher efficiency fans, or liquid cooling).

Standard 90.4 is a that focuses on two primary metrics: the Mechanical Load Component (MLC) and the Electrical Loss Component (ELC).

ASHRAE provides a of its popular standards, including 90.4, on their official website. This version cannot be downloaded, printed, or searched via Ctrl+F, but it allows you to verify quick technical tables or paragraphs without paying upfront. A Warning on Free PDF Downloads

What is the for your data centre project?