The ASHRAE Allowable Envelope is the broader range of inlet temperature and humidity within which IT equipment is designed to function, defined by classes such as A1 through A4. In data centers brief excursions beyond the recommended envelope but inside the allowable range are acceptable, enabling more economizer hours and energy savings. Class A3 and A4 extend upper limits to 40-45 degrees C.
Category: Cooling & Environmental Control · Subcategory: Environmental Monitoring · Part of the AIDC Technical Terminology reference.