Unmanned Evaluation Of Various Umbilical Supplied Open Circuit Demand Uba Underwater Breathing Apparatus For Ptc Personnel Transfer Capsule Bell Diving

During July and August 1986 NEDU conducted unmanned studies to evaluate a number of umbilical supplied, open circuit, demand UBAs for potential use in saturation diving from PTCs. The following UBAs were tested at various depths and RMVs to 1000 FSW using both 100 ft 3/8 in ID and 100 ft 1/2 in ID diver's umbilicals: USN MK 1 MOD O Bandmask, USN MK 1 MOD Bandmask, AGA Divator MK II Full Face Mask, DSI Superlite 17B, DSI Heliox 18B, DSI Superlite 17B/GSOL Ultraflow 350, and DSI Superlite 17B/GSOL Ultraflow 500. The use of a volume tank in the PTC was also investigated. The results of the testing showed that only the DSI Superlite 17B of Heliox 18B fitted with GSOL Ultraflow 500 and GSOL Ultraflow 350 were able to meet current NEDU performance goals to 1000 FSW. All other UBAs failed to meet NEDU performance goals for work of breathing.

The Navy Experimental Diving Unit (NEDU) conducted unmanned performance testing on two first production article MK 16 underwater breathing apparatus (UBA) in October 1982. Breathing resistance/breathing work and oxygen (O2) set-point control studies were conducted in the NEDU Experimental Diving Facility (EDF) on air and helium oxygen (Heo2) at depths to 300 FSW using a hyperbaric breathing simulator. In addition, carbon dioxide (CO2) absorbent canister durations were conducted on both air and HeO2 at depths to 300 FSW in water temperatures ranging from 29 to 90F. Results of the unmanned performance testing revealed the breathing resistance/breathing work and CO2 absorbent canister durations were slightly improved over the pre-production model tested in January 1980. Initial testing of the MK 16 first article O2 set-point control system showed both units to be operating properly and within established limits. However, each UBA O2 add system completely failed to calibrate in the latter stages of the evaluation. This serious life support system failure requires tht follow-on testing of the MK 16 O2 add system be conducted by NEDU after the problem is corrected.

The Navy Experimental Diving Unit (NEDU) performed unmanned testing on a U.S. Navy MK 15 and modified MK 15 closed-circuit (C/C) underwater breathing apparatus (UBA) using a hyperbaric breathing simulator. The purpose of these tests was twofold: (1) to evaluate breathing resistance/breathing work characteristics of the MK 15 and modified MK 15 UBAs using a variety of mouthpiece and hose configurations and (2) to evaluate carbon dioxide (C02) absorbent canister duration for the modified MK 15 UBA at a depth of 50 feet-of-seawater (FSW) in a wide range of water temperatures. Breathing resistance/breathing work studies were made using five different mouthpiece and hose configurations at depths to 150 FSW at simulated work rates ranging from light to extreme. C02 canister duration tests were conducted in water temperatures ranging from 29 to 90 F. The modified MK 15 UBA (MK 15 1/2) was equipped with the following changes effecting rig performance: (1) a MK 16 UBA center section providing increased scrubber capacity and better thermal protection and (2) the Rexnord prototype mouthpiece with the larger diameter MK 16 hoses.

The Navy Experimental Diving Unit (NEDU) evaluated the prototype U.S. Navy Underwater Breathing Apparatus EX-16 in the following configurations: (1) standard hoses with MK-6 mouthpiece; (2) enlarged breathing hoses with MK-6 mouthpiece; and (3) enlarged breathing hoses and the AGA full face mask. A series of unmanned tests was conducted to determine performance characteristics of the various EX-16 configurations. Data derived from these tests will be used in follow-on development and testing of the EX-16 UBA. Results indicate the AGA full face mask with its larger breathing hoses to be the optimum combination for low diver respiratory work. The scrubber canister design is deemed adequate and further modifications are unnecessary. (Author).