Low Temperature Limit Evaluation of Mk 21 Mod 1 UBA Using Reduced Overbottom (O/B) Pressure and Extended Gas Umbilical Length
Test rept. Jun-Dec 1993
NAVY EXPERIMENTAL DIVING UNIT PANAMA CITY FL
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This report addressed three issues regarding the performance of the MK 21 MOD 1 UBA during unmanned testing. First, the influence of oral-nasal OIN mask seal integrity on work of breathing WOB levels was characterized. WOB Levels were measured with the ON mask in three configurations 1 cemented directly to a test mannequin 2 fitted to, but not cemented on the mannequin and 3 removed from the UBA. Second, the low temperature operating Limit, defined by the absence of ice formation in the UBA when operated to 60.65 msw 198 fsw, was established. Third, the performance of M 21 MOD 1 UBAs, modified by Navy Experimental Diving Unit and Diving Systems International to reduce the likelihood of free-flow, was compared using 621 and 931 kPa 90 and 135 psi overbottom 0B pressure air delivered through 91.44 m 300 ft 9.5 mm .375 in ID umbilicals. MK21 MOD 1, WOB work of breathing, 0B overbottom pressure, Cold water limits.
- Life Support Systems