The McKinley Climatic Lab facility at Eglin AFB. We use them for hot and cold weather testing, where we don't have a requirement to fly immediately after the soak. Running engines, APU's etc in the chamber is possible up to TOP.
If we need to carry out a cold soak followed immediately by a flight, we generally resort to the Frobisher, Resolute Bay, Iqaluit option.
http://www.aiaa.org/tc/gt/facility_d...imatic2008.pdf
Edit: The chamber also has the capibility to generate snow and ice for accretion testing.