TEMPERATURE-HUMIDITY REQUIREMENTS. Experimental data relating comfort
to temperature and humidity for hyperbaric conditions is very scarce.
However, guidelines can be established from past chamber experience.
Temperature. Chamber temperatures in the range of 70 to 80 deg. F
are required for air missions to 200 feet, however, helium-oxygen missions
require higher-than-normal temperatures to keep occupants comfortable.
Chamber temperatures in the range of 85 to 95 deg. F are required at the 400
to 2000-foot depths. Helium heat transfer properties and increased density
are responsible for greater quantities of heat being convected away from the
body. Lower pressures and gas mixes more closely resembling air dictate
progressively lower gas temperatures for comfortable body temperature
The designer should note that the comfort range for
helium dives is very narrow. Adequate control equipment
must be provided.
b. Humidity. Experience has shown humidity requirements to be the same
for hyperbaric atmospheres as for normal atmospheres. In general, the
humidity should not be under 30 percent and normally controlled between 50
and 70 percent.