Emergency Breathing Apparatus MK 18 Mod 1 Canister Performance Study at 844 FSW

摘要

The MK 18 MOD 1 emergency breathing apparatus (EBA) is a semi-closed circuit breathing apparatus designed to operate as a component of a built-in breathing system (BIBS) in a diver support facility. The EBA design includes two gas flow orifices, one to support a working diver, Oxygen consumption rate 3.0 slpm, the other to support a resting diver, Oxygen consumption rate 0.75 slpm. High Performance Sodasorb or LiOH can be used as the Carbon dioxide absorbents within the canister. The design canister duration was 3 hours. Testing was performed at 844 FSW during an HeO2 saturation dive at the Navy Experimental Diving Unit, Panama City, FL. The chamber temperature was 28 + or - 1 C. The diver performed 15 minutes of work at a 175 watt load on calibrated bicycle ergometer within a dry chamber. The diver then rested for 195 minutes. The divers' successful completion of the exercise, a canister effluent CO2 level below 1% SEV, and their subjective comments determined the acceptability of the EBA. Only 2 trials were performed using Lithium hydroxide because of the high inhalation gas temperature of 43 C which restricted the diver's work performance. Four trials were performed using HP Sodasorb. The maximum inhalation gas temperature was 39 C. At rest the gas temperature was approximately 33 C. The CO2 levels never exceeded 1.5% surface equivalent value during work or rest. The divers did not find the EBA any more difficult to use than the BIBS.