result of repeated test at CE conditions, now plug pushed inside the EAC to avoid any leak
1.6l STPD, 40 RMV, 2liter tidal, 40m depth, 4°C
5 mbar 49 minutes 20 mbar 68 minutes
if anyone is confused, because of all the fog that has been created here, between the 5 mbar end of inhale and the max 20 mbar VWA, take a look at the standard:
chapter 5.6.6: scrubber endurance is given when the end of inhale inspired partial pressure reaches 5mbar: the end of inhale gas is the same gas as in the inhale lungs, as after the complete inhale breath, the mouthpiece is completely rinced with the inhaled gas coming from the inhale lung: you also see this in the breath by breath graphs
why sample the gas from the inhale lung: simple: to get far more accuracy: the max % you reach in the inhale lung at break trough is 0.1% at 40 meter, and 0.4% at 20 mbar: so we use a CO2 sensor with a max span of 0.5%, calibrated with a 5000PPM gas
in the mouthpiece, the % peaks to 10/20 times higher easely, so to measure there, we take a 5% or 10% span CO2 sensor
everybody knows that exactly measuring 0.1% with a 10% span CO2 meter is... bad laboratory practice
there is a second requirement:
chapter 5.6.1.5: max volume weighted inspired partial pressure of CO2 may never reach 20mbar, during any stated endurance: this is to avoid big mouthpieces
for normal sized mouthpieces, this is never a problem as when reaching the endurance limit of 5mbar, the VWA in the moutpiece is maybe between 6.5 and 7.5 mbar, depending on the dead volume and shape: so this one never limits the endurance
so all the fuzz about people that state false endurance because of sampling gas in the inhale lung, and not taking the VWA from the mouthpiece.... once again, all fuzz, nothing more....
anyone cares to show the graphs, mail me, I will PM them
