Thermal measurements on divers in hyperbaric helium-oxygen environments

Area of Science:

• Physiology
• Diving Medicine
• Environmental Extremes

Background:

• Saturation diving operations often occur in environments with uncontrolled temperatures.
• Cold stress poses significant risks to divers, impacting their physiological tolerance and safety.
• Understanding heat loss mechanisms is vital for establishing safe diving protocols.

Purpose of the Study:

• To quantify the rate of heat loss in unclad divers exposed to helium-oxygen environments at simulated depths.
• To determine the temperature-time relationship defining diver thermal limitations in cold hyperbaric conditions.
• To assess physiological thermal insulation and identify body areas most susceptible to heat loss.

Main Methods:

• Conducted three saturation dives to simulated depths of 1000, 1200, and 1400 fsw.
• Monitored body core and mean skin temperatures of up to four subjects over 2-hour periods.
• Measured mean body convective heat loss in some subjects to calculate thermal insulation.

Main Results:

• Established heat loss rates for divers in heliox at 15, 20, and 25°C.
• Developed depth-time-temperature graphs illustrating diver thermal limitations based on core and skin temperature changes.
• Ranked body areas by susceptibility to heat loss and temperature decrease.

Conclusions:

• The study provides critical data for defining safe thermal exposure limits for saturation divers.
• Findings are applicable to divers in cold diving bells and uncontrolled hyperbaric chambers.
• Results aid in mitigating risks associated with cold stress in deep-sea operations.