Effects on Scrubber Endurance of Storing Soda Lime in CF Rebreathers

摘要

Canadian Forces divers using rebreather diving apparatus are currently restrictedto pre-dive preparation times of only 6 hours. A proposal was made to increase this time to 7 days. Theoretically, this was possible; however, no empirical data were available to indicate that the chemical carbon dioxide absorbent could survive an extended storage period in Canadian Forces rebreathers. Consequently, the Experimental Diving Unit of the Defence and Civil Institute of Environmental Medicine conducted a study to determine if storage of soda lime would reduce the carbon dioxide scrubber endurance. The tests measured scrubber endurance using proposed NATO standard procedures under three conditions: (a) no storage; (b) seven days of storage; and (c) 1 hour under the endurance test conditions, followed by 7 days storage and then completion of the endurance test. The results indicated no difference between the three conditions; thereby, supporting the proposal for up to 7 days of storage. On the other hand, issues related to cold weather operations biological hazards, heavy exertion and accelerated material wear imposed some restrictions on rebreather storage.