ASHRAE
The engineering society whose thermal guidelines define the temperature and humidity envelopes for IT equipment.
Current numbers
~41 °C FWS -> 45 °C rack coolantwarm-water facility-loop target (NVIDIA Vera Rubin) enabling dry-cooler / compressor-less rejection; ASHRAE roadmap argues ~30 C standard
W17–W45+ASHRAE liquid classes by max supply water temp (17/27/32/40/45 °C, plus W+); all share a 2 °C lower limit
Gd 0 / 1.1 / 1.6ASHRAE commissioning-process / Basis-of-Design / data-center-specific Cx guidelines; Std 202 formalizes the Cx-Process