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The CO2 readings are definitely high, especially in the test without
life support. I know that when I used the monitor out in the open
the CO2 percentage was between .01 and .03 so I don't expect a
calibration error is the cause of the high readings unless something
happened to the device during shipment. That should be easy enough
for Alec to test however by simply going to an open area and
checking the CO2 reading. Because the oxygen levels are also low it sounds feasible that the initial environment was the result of respiration while getting both people settled in the cabin and starting the test, although it doesn't really explain the drop in CO2 from 1.6 percent at the end of the no-life-support test to the beginning of the radial-fan test. It looks to me like even the radial fan had a problem keeping up with the CO2 levels. It rises from .2 to .3 percent in the first four minutes and then goes back down to .2 percent at 15 minutes and then starts rising again. Given the CO2 data from both fan tests it might appear that the scrubber is not efficient enough to handle two people in the cabin. Perhaps another scrubber is necessary or a larger one, or there is something wrong with the airflow over the sofnolime (packed too hard, obstruction, or fan is not powerful enough). I would have expected the scrubber to handle not only the respiration of the occupants but also reduce the CO2 concentration of the existing atmosphere from the time the test started. I find the no-life-support CO2 levels very interesting given how quickly the levels accumulate. At about 43 minutes the CO2 level would have been at 3% or the maximum short term exposure allowed by OSHA. Simultaneously, the O2 level would have hovered around 16%, borderline survivable and certainly requiring immediate surfacing. What it really illustrates is that getting into a situation where you cannot surface at the end of your planned dive, is really going to ruin your day. Without life support, there's no room for error, accident, or circumstance. Jon On 8/7/2011 2:37 AM, Cliff Redus wrote:
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