As I have said elsewhere at the moment the recommended duration of 3 hours is not an issue based on profiles I am doing now, but if everything goes according to plan, eventually I would envisage getting to a point where 3 hours may not be enough.
I am interested to hear what others views are on the duration of the scrubber, I have read various approaches on RBW Scrubber duration on the KISS and Mark has used the following to give some kind of calculated stab at what the canister should at more realistic breathing rates than the tests specify:
KISS is prety good due to the long scrubber housing increasing dwell time. Conversly this affects WOB, but as I have said before the WOB issues on the KISS were mainly in the hoses and mouthpiece IMHO
Theres a mathematical calculation for theoretical scrubber time which can be simplified with a margin of error built in.
C02 = 85% of V02
V02 = 4% RMV
SO take an RMV of 20lpm and you get 0.8 of which 85% = 0.68 (call it .7)
SO the KISS scrubber tested at 40m at 4c and 1.6lpm co2 = 157min run
1.6 devided by .7 = 2.28
Multiply 157 by 2.28 and you get 359mins or 5.9hours
If you accept water temperature has a significant effect on scrubber efficiency then you will appreciate the same test done in 15c water would give better results
But depth is also a factor as the testing is all at 40m. So there needs to be a view on time spent at depth?
Personally I have done 6 hours on a KISS several times but the water temp was 20c and my max depth was 14m
OW diving deep, I never did more than 4 hours 15mins after about an hour around 60-65m
Again personally, I never got excited about pushing 5-6 on a single deep dive (though only did that on the Inspo) and I never got excited about 6 doing 20c+ 14m max multiple Mexico cave dives
However I'd never do three X two hour 40m dives (if that makes sense) Id do two no problem, but being at 40m for 45mins for the third dive was a no no in my book
TOTAL Chasey voodo but I would stay happy and confident in my own belief bubble and that's the point. If your belief bubble is 3 hours, stick with that as theres no need to push scrubbers and the consequences of them failing are dire.
I am interested to hear what others views are on the duration of the scrubber, I have read various approaches on RBW Scrubber duration on the KISS and Mark has used the following to give some kind of calculated stab at what the canister should at more realistic breathing rates than the tests specify:
KISS is prety good due to the long scrubber housing increasing dwell time. Conversly this affects WOB, but as I have said before the WOB issues on the KISS were mainly in the hoses and mouthpiece IMHO
Theres a mathematical calculation for theoretical scrubber time which can be simplified with a margin of error built in.
C02 = 85% of V02
V02 = 4% RMV
SO take an RMV of 20lpm and you get 0.8 of which 85% = 0.68 (call it .7)
SO the KISS scrubber tested at 40m at 4c and 1.6lpm co2 = 157min run
1.6 devided by .7 = 2.28
Multiply 157 by 2.28 and you get 359mins or 5.9hours
If you accept water temperature has a significant effect on scrubber efficiency then you will appreciate the same test done in 15c water would give better results
But depth is also a factor as the testing is all at 40m. So there needs to be a view on time spent at depth?
Personally I have done 6 hours on a KISS several times but the water temp was 20c and my max depth was 14m
OW diving deep, I never did more than 4 hours 15mins after about an hour around 60-65m
Again personally, I never got excited about pushing 5-6 on a single deep dive (though only did that on the Inspo) and I never got excited about 6 doing 20c+ 14m max multiple Mexico cave dives
However I'd never do three X two hour 40m dives (if that makes sense) Id do two no problem, but being at 40m for 45mins for the third dive was a no no in my book
TOTAL Chasey voodo but I would stay happy and confident in my own belief bubble and that's the point. If your belief bubble is 3 hours, stick with that as theres no need to push scrubbers and the consequences of them failing are dire.
Comment