Performance of life support breathing apparatus for under-ice diving operations

Area of Science:

• Physiology and Performance
• Marine Biology
• Equipment Engineering

Background:

• Cold-water diving presents risks of scuba regulator malfunction, including air supply failure.
• Single-hose regulators are particularly susceptible to freezing and malfunction in sub-zero water temperatures.

Purpose of the Study:

• To evaluate the under-ice performance of commercially available scuba regulators in Antarctic conditions.
• To identify regulators with superior reliability for extreme cold-water environments.

Main Methods:

• Seventeen science divers conducted 305 dives in -1.86°C Antarctic seawater under 6m thick ice.
• Sixty-nine regulators of 17 models from 12 manufacturers were tested.
• Dive profiles averaged 30 msw depth and 29 minutes, with freeflow events recorded.

Main Results:

• A total of 65 freeflows occurred across all regulators.
• Seven regulators classified as 'acceptable' had a 6% freeflow incidence (9/146 exposures).
• Ten regulators classified as 'unacceptable' had a 35% freeflow incidence (56/159 exposures).

Conclusions:

• The performance of the seven best-performing regulators was significantly better than the remaining ten.
• This study provides critical data for selecting reliable scuba equipment for extreme cold-water diving.
• Regulator choice significantly impacts diver safety in sub-zero marine environments.