The US Navy monitors atmospheric constituents aboard nuclear submarines with a ruggedized mass spectrometer called the Central Atmosphere Monitoring System (CAMS). The CAMS aboard each submarine is capable of sensing oxygen, nitrogen, carbon dioxide, carbon monoxide, water vapor and refrigerants in all regularly occupied spaces. This setup fulfills the majority of the Navy’s needs, however, the CAMS is not capable of “sniffing” enclosed spaces nor providing data after certain casualty situations.
To meet these two critical needs and provide backup monitoring capability for the CAMS, the US Navy currently uses various gas-sensing colorimetric tubes. Aside from the traditional unpopularity of these tubes with the fleet, recent investigations have shown them to be inefficient, expensive and difficult to obtain. With that background, testing was funded to determine if the colorimetric tubes could be replaced with modern portable atmosphere monitoring equipment. Testing was required because submarines can have a high background hydrogen level, up to 10,000 ppm, that interferes with portable atmosphere monitoring equipment. Overall, testing showed that portable analyzers could replace the colorimetric tubes used to monitor life gases, such as, oxygen, carbon dioxide and carbon monoxide when carefully selected based on cross sensitivity data. Results of testing and performance comparisons for these gases will be provided. Testing to replace colorimetric tubes used to monitor for other gases are ongoing.