Dell Latitude 5420 Owner's Manual page 222

Altitude
(maximum):
Operating –15.20 m to
3048 m (–50 ft
to 10,000 ft)
Non- –15.20 m to
Operating 10,668 m (–50
ft to 35,000 ft)
Airborne G1 or lower as
contaminant defined by ISA-
level S71.04–1985