Dell OptiPlex 990 (Early 2011) - Manual (Page 92)

Environmental
Storage 105 G
Altitude:
Operating –15.2 m to 3048 m (–50 ft to 10,000 ft)
Storage –15.2 m to 10,668 m (–50 ft to 35,000 ft)
Airborne contaminant level G1 or lower as defined by ANSI/ISA-
S71.04-1985
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