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Manned Certification Tests of the Modernized MK 16 MOD 1

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Technical Report,01 May 2010,30 Nov 2013

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Navy Experimental Diving Unit Panama City United States

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The MK 16 MOD 1 closed-circuit underwater breathing apparatus UBA has received modernized oxygen control electronics. As part of the certification process for these electronics, manned dives were performed during which PO2 was monitored with an independent oxygen sensor placed in the UBA inspiratory hose. Twenty-four divers using six modernized MK 16 MOD 1 UBAs performed 63 dives 20 each at 130 feet of sea water fsw for 30 minutes and 150 fsw for 35 minutes, and 23 at 300 fsw for 20 minutes 40, 45 and 91 msw. Decompression was according U.S. Navy Diving Manual. Recordings of steady-state oxygen control around the nominal 1.3 atm PO2 set point, oxygen overshoot PO2 above 1.45 atm due to descent, and oxygen undershoot PO2 below 1.15 atm due to ascent from the present dives were compared to specified oxygen control performance criteria and to data from previous manned dives with the legacy MK 16 MOD 1. The modernized MK 16 MOD 1 passed the predefined performance criteria and was comparable to the legacy UBA. Compared to the legacy MK 16 MOD1, the modernized MK 16 MOD 1 had less oxygen overshoot and a lower steady-state PO2 on the bottom, although the latter was above the nominal 1.3 atm set point. These PO2s did not result in a significantly increased estimated risk of decompression sickness in the modernized compared to the legacy MK 16 MOD 1 for the schedules tested, but a significantly increased risk might result from longer dives four hours. Modernized MK 16 MOD 1 steady-state PO2 drifted down during the course of a dive. The downward drift in PO2 decompression was explained by poor temperature compensation in the UBA oxygen control sensors available at the time.

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