ASHRAE fifth-edition equipment air and liquid classes; separate 2024 liquid-cooling resiliency bulletin
A1–A4 + H1 / W17, W27, W32, W40, W45, W+observed
| Value kind | observed — Reported measurements, counts, and specifications keep the precision and scope stated by their source; an exact specification is not treated as a range. |
|---|---|
| Scope | Equipment capability classes, not chosen operating points. Do not infer a rack TCS temperature, FWS setpoint, return temperature, or PUE from a class alone. |
| As of | 2021 |
| Source | ASHRAE AI Data Center Energy Performance Framework, Figure 2, confirms W17/W27/W32/W40/W45/W+. H1 is recorded in ASHRAE’s fifth-edition Thermal Guidelines; the 2024 resiliency publication is a separate Technical Bulletin. H1 primary reference: https://www.ashrae.org/file%20library/technical%20resources/bookstore/emergence-and-expansion-of-liquid-cooling-in-mainstream-data-centers_wp.pdf (2021), fifth-edition discussion. · Introduction and Purpose, Figure 2; companion fifth-edition Thermal Guidelines documentation |
| Review | checking…review by 2027-03-05 · slow cadence |
| Recorded changes | last 2026-09-16 · 3 revisions tracked |
| Claim id | ashrae-tc-9-9-air-classes-and-liquid-w-classes |
Where the guide uses it
← Full numbers register — every date-stamped figure in the guide, with revision history.