Dell PowerEdge M1000e Getting Started Manual page 12

Environmental
Storage
Airborne contaminant level
Class
12
NOTE: For altitudes above 2950 ft, the maximum
operating temperature is derated 1 ºF per 550 ft.
–15.2 m to 10,668 m (–50 ft to 35,000 ft)
G1 as defined by ISA-S71.04-1985