Development of Oxygen Monitoring Capability for the Existing Hyperbaric Carbon Dioxide Analyzer Used in Dry Deck Shelter Operations

摘要

The Dry Deck Shelter (DDS) is a hyperbaric system used on submarines to transport SEAL delivery vehicles into an operating area. The system uses air from submarine banks to ventilate the DDS for carbon dioxide (CO(2)) removal and provide breathing air to the divers. In order to improve the efficiency of ventilation, we previously developed a portable hyperbaric analyzer for monitoring CO(2) within DDSs. This analyzer was approved by NAVSEA (PMS-399) in 1998 as the primary control of ventilation during DDS operations. However, when divers operating from the DDS develop decompression sickness, they can be treated in the chamber compartment of the DDS using recompression and oxygen (O(2)) for breathing via masks connected to the built-in- breathing System (BIBS) . Concern exists about leakage of O(2) from the masks producing a rise in the O(2) levels within the chamber, thus increasing the fire hazard. Consequently, we were tasked to add an O(2) monitoring capability to the hyperbaric CO(2) analyzers now used inside the DDS. preliminary laboratory testing of candidate 0(2) sensors allowed selection of a commercially available sensor, which was then incorporated into the CO(2) analyzer. Experiments evaluating the performance of the C0(2)/O(2) analyzer in the laboratory demonstrated 0(2) accuracy of +5% relative over 1-4 atmospheres absolute (ATA), although greater error at 5-6 ATA, and confirmed previously reported CO2 accuracy of +10% relative over the same pressure range. Because neither long- term testing nor field evaluation of the C0(2)/O(2) analyzers has been performed, analyzer reliability will need to be followed carefully during any transition to Fleet use. In addition to meeting the requirements for 0(2) and CO(2) measurement during DDS operations, this analyzer may also fill the existing need for reliable 0(2) and CO(2) measurement inside other types of hyperbaric chambers and diving apparatus.