Scurbber duration on Evolution Rebreather

Johnny Christensen · 9th August 2006, 17:39

Quote: (Originally Posted by mortenstigbach)

Yes .... there are heated pools in Denmark, but at the moment water temperature is about 22-23 degress celcius at the surface.....

Yes... but go for a dip in the Baltic Sea and it drops to 2-4 degrees on the bottom.
Just got a new eletrical divers vest, can't wait to try it out

**Gill Envy** · 9th August 2006, 17:42

Quote: (Originally Posted by mortenstigbach)

How long time is the scrubber duration on a Evolution Rebreather?

What if you only dive 1 hour a day - do you then "loose" the rest of the scrubber (trash it??) or can it last in the canister box ? - Temp stic ?

Morten Stig Bach

We factor in the rating, the conditions under which the rating is based (pretty much worst case) and the dive(s) we are doing (usually significantly shallower and under less work load than the rating). We use the temp stick to help us get a more precise sense of the real time remaining capacity. We do a lot of dives within recreational limits. The limits i feel comfortable with at this point are: I'm willing to use the same sorb for multiple dives, with up to a week or so inbetween, if the dives are within recreational limits (130 fsw). Each consecutive dive tends to be shallower. I will not start a dive to or below 100 fsw if i have 3 + hours on the sorb, in that case i'll dump old sorb and dive fresh. if i'm planning on going below 130 fsw, i start with fresh sorb. We get somewhere between 4-5 hours typically to a fill, staying within the temp stick's safety margine and within recreational limits. I see no reason to exceed 4-5 hours regardless of what the temp stick showes, my overall sense of it's actual ability would trump the temp stick at that point and the sorb would get chucked. if i was diving deeper than 130 on a regular basis my habits would be adjusted accordingly...i'd chuck the scrubber after each dive and probably be reporting that the temp stick allows me more like 2-3.5 hrs, i'm guessing.

when diving within recreational limits, I take the canister out at the end of the day and let dry in open air for about 8 hours, then seal it up in a plastic bag for storage. There are no hard facts on what the effect of storing partially used sorb has on it's remaining duration, but it seems like common sense to not push it much beyond a week, though i've read on this board that some people keep it for several weeks with no incident. One time i had a fill that had one hour on it on a shallow dive and it was three weeks before i dove again...I winged it a bit i guess, pre breathed it to see what it would do and then did another shallow dive at that point and the temp stick picked up right where it left off once pre-breahed and at depth.

since sorb is stored sometimes for years before being used the first time, it seems very up in the air as to the effect that time has on used sorb. Certainly it's at a higher moisture content for the storage period post use, and since exposed to near saturated high humidity during the dive there are questions in my mind as to what effect that has...if it degrates further if stored for prolonged periods?...I've decided for me, it's best to just not keep it beyond a week and under previously stated limits but my guess is that time has very little effect on it as long as it's not exposed to a suply of CO2.

I'm working on a tag that will go with the scrubber once out of the unit that identifies who's unit it came from (my wife has an evo too), the max depth and duration of each dive and perhaps what the temp stick showed at the max depth of the last dive (so that i can plan the next dive with more information).

01RMB · 10th August 2006, 02:16

I have tended to use the sorb (the recommended Sofnolime 1025 - fine grain) in the Evo over multiple dives for up to 4-5 hours at about 20-24 degrees c depending on the depth and work load. I will reuse sorb for multiple dives and will let the head and sorb dry overnight if I am doing dives over multiple days.

Experience with the temp stik has proven a good guide to how much the sorb has been used and an indication of how long you could reasonable expect it to last on future dives. The temp stik reading is not definitive and does not show you in minutes the remaining time. You have to use it like a fuel gauge in your car and know that if you are at depth or working hard then it will not last as long like if you were driving in peak hour city traffic the remaining fuel in your tank will not get you as far.

If the black bar is full width and you are planning another dive which won’t be too long, too deep or too hard work then you can go again without changing the sorb. If it shows only a little black bar on the right then it is time to change the sorb. If it shows only one bar and the warning has gone off - it is time to surface and if the warning says the sorb has been totally used up it is time to go open circuit NOW.

If I am planning on doing a longer, deeper dive or potentially more risky dive then I will make sure that there will be enough sorb duration remaining for the dive by changing it. And as is prudent I allow enough margin to allow for contingencies and always have enough bail out to go to open circuit if required. BUT - If in doubt throw it out.

After a dive I will take the inner sorb cannister out and after leaving the scrubber canister to dry overnight I will seal it back up in a waterproof sealed dry bag or I put it back into the outside canister and seal it using the plugs and cap from Narked@90 (http://www.narkedat90.co.uk/33.html)

diverrob · 10th August 2006, 04:23

Quote: (Originally Posted by 01RMB)

After a dive I will take the inner sorb cannister out and after leaving the scrubber canister to dry overnight I will seal it back up in a waterproof sealed dry bag or I put it back into the outside canister and seal it using the plugs and cap from Narked@90 (http://www.narkedat90.co.uk/33.html)

I agree with your thinking I too reuse my sorb and also monitor the temp stick. As for storing my sorb between dives I came up with a sealed and bullet proof way that works very well! It is really handy on boat trips where space is limited and your sorb may get bumped or banged around.

mortenkjerulff · 10th August 2006, 06:33

Quote: (Originally Posted by Gillenvy)

...

perhaps a cogent question would be, has anyone using vision electronics gotten what they think was a co2 hit when the scrubber indicated they were still in the green and if so, under what conditions?

Yes. I have seen this happen. Not to me, but to a diver on the same liveaboard. It was on an inspiration, and as far as I remember well within the 3 hour CE-limit and the temp-stick showed no sign of troubles. Water temperature was about 6-8 degrees, and depth about 35 meters.

Morten

decoweenie · 10th August 2006, 10:12

Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one!

I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else.

There are a lot of factors that contribute to the symptoms that people think is a CO2 hit.

mortenkjerulff · 10th August 2006, 10:38

Quote: (Originally Posted by decoweenie)

Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one!

I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else.

There are a lot of factors that contribute to the symptoms that people think is a CO2 hit.

Point taken.
But how will one ever know for sure?

The symptoms did include headache and fattigue after the dive.

MattDuke · 10th August 2006, 11:24

Quote: (Originally Posted by decoweenie)

IMHO, the answer is... "2 hours under the worse possible conditions".

And that'd be the shortest duration limit since they are not practical test conditions that normally could be repeated in reality.

Someone could adhere to this 2-hour limit, and have a lot (and I mean A LOT) of safety. But, IMHO, it is not correct to interpret it as the upper limit.

Again, just IMHO...

OK, I am a complete novice on CCR, but I thought that by sticking to this limit a diver gives himself a degree of safety for the "Unexpected" Perhaps the surface condtions/current require more exercise than expected. Perhaps the buddy has a problem and you (Righly or wrongly) drop down and try and help.

If you stick to the "worse possible conditions" standard for your scrubber, maybe it will save you one day when an unexpected event happens?

Perhaps as I get more experienced on CCR I will see my thoughts as very nieve, but for me the simple answer would be. If you need more than 2 hours scrubber, don't by an evo. Whatever unit you buy, stick to the scrubber run time as instructed and hopefully give your self that lucky break if something really bad happens.

As I said. Matt=CCR noob. But that's how I see it for my novice position.

As always more knowledge may explain why you would overrun a scrubber, but it seems dodgy to me.

EDIT: I have been diving by the rule of thirds for so long now OC; that I kinda see the same need on a scrubber, to a lesser extent. When underwater, I don't want any lifesupport system being used to the "Limit".

Johnny Christensen · 10th August 2006, 11:48

Quote: (Originally Posted by decoweenie)

Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one!

I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else.

There are a lot of factors that contribute to the symptoms that people think is a CO2 hit.

Well, it was my buddy it happened to. And in the past I've seen him still being in control of the situation when other people would have run away screaming. So for him to completly loose control of his breathing, there had to be a very good reason.

All the "right" conditions where there. Semi rough surface conditions when we jumped in. A bit of current when we pulled us down. He used only his ADV to supply gas on the way down, thereby having a bit higher WOB compared to manual gas addition when you are a adding gas before you bottom out on the CL.
We went against a mild current on the wreck, he was less streamlined than I was.
I ducked down to the stern of the wreck, to get out of the current and relax. He never made it so far and had to return by current to the shotline. I missed that part and started searching at the bottom of the wreck, where I expected to find him on the opposite side.
Meanwhile he was flushing the unit and going back to the shotline. At the time where he was there again, his breath was so out of control that he could only look at the OC bailout reg he was holding in his hand, but in no way perform the switch. He looked at the scrubber gauge and it told him that everything was just fine...
For some kind of reason, he did not quite believe that.

Afterwards he had a headache, and had to take a couple of hours in his bunk.
He reported that while it went on, he had a very rapid heart rate.

Scrubber use was 2 hrs 45 min.

GolemGear BOV is to be fitted as soon as it arrives

decoweenie · 10th August 2006, 13:10

Johnny,

In the context of the current discussion, it sounds more like your buddy got winded from the heavy work. And over-breathed the loop rather than a scrubber exhaustion.

9th August 2006, 17:39	#11 (permalink)
Johnny Christensen Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Apr 2006 Location: Denmark Posts: 304	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by mortenstigbach) Yes .... there are heated pools in Denmark, but at the moment water temperature is about 22-23 degress celcius at the surface..... Yes... but go for a dip in the Baltic Sea and it drops to 2-4 degrees on the bottom. Just got a new eletrical divers vest, can't wait to try it out __________________ www.johnnychristensen.com Wreckphotography from the cold north
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9th August 2006, 17:42	#12 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,314	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by mortenstigbach) How long time is the scrubber duration on a Evolution Rebreather? What if you only dive 1 hour a day - do you then "loose" the rest of the scrubber (trash it??) or can it last in the canister box ? - Temp stic ? Morten Stig Bach We factor in the rating, the conditions under which the rating is based (pretty much worst case) and the dive(s) we are doing (usually significantly shallower and under less work load than the rating). We use the temp stick to help us get a more precise sense of the real time remaining capacity. We do a lot of dives within recreational limits. The limits i feel comfortable with at this point are: I'm willing to use the same sorb for multiple dives, with up to a week or so inbetween, if the dives are within recreational limits (130 fsw). Each consecutive dive tends to be shallower. I will not start a dive to or below 100 fsw if i have 3 + hours on the sorb, in that case i'll dump old sorb and dive fresh. if i'm planning on going below 130 fsw, i start with fresh sorb. We get somewhere between 4-5 hours typically to a fill, staying within the temp stick's safety margine and within recreational limits. I see no reason to exceed 4-5 hours regardless of what the temp stick showes, my overall sense of it's actual ability would trump the temp stick at that point and the sorb would get chucked. if i was diving deeper than 130 on a regular basis my habits would be adjusted accordingly...i'd chuck the scrubber after each dive and probably be reporting that the temp stick allows me more like 2-3.5 hrs, i'm guessing. when diving within recreational limits, I take the canister out at the end of the day and let dry in open air for about 8 hours, then seal it up in a plastic bag for storage. There are no hard facts on what the effect of storing partially used sorb has on it's remaining duration, but it seems like common sense to not push it much beyond a week, though i've read on this board that some people keep it for several weeks with no incident. One time i had a fill that had one hour on it on a shallow dive and it was three weeks before i dove again...I winged it a bit i guess, pre breathed it to see what it would do and then did another shallow dive at that point and the temp stick picked up right where it left off once pre-breahed and at depth. since sorb is stored sometimes for years before being used the first time, it seems very up in the air as to the effect that time has on used sorb. Certainly it's at a higher moisture content for the storage period post use, and since exposed to near saturated high humidity during the dive there are questions in my mind as to what effect that has...if it degrates further if stored for prolonged periods?...I've decided for me, it's best to just not keep it beyond a week and under previously stated limits but my guess is that time has very little effect on it as long as it's not exposed to a suply of CO2. I'm working on a tag that will go with the scrubber once out of the unit that identifies who's unit it came from (my wife has an evo too), the max depth and duration of each dive and perhaps what the temp stick showed at the max depth of the last dive (so that i can plan the next dive with more information). __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 9th August 2006 at 17:56.
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10th August 2006, 02:16	#13 (permalink)
01RMB Evolving Current Rebreather/s: Evolution Other Rebreather/s: Join Date: May 2005 Location: Brisbane, Australia Posts: 190	Re: Scurbber duration on Evolution Rebreather I have tended to use the sorb (the recommended Sofnolime 1025 - fine grain) in the Evo over multiple dives for up to 4-5 hours at about 20-24 degrees c depending on the depth and work load. I will reuse sorb for multiple dives and will let the head and sorb dry overnight if I am doing dives over multiple days. Experience with the temp stik has proven a good guide to how much the sorb has been used and an indication of how long you could reasonable expect it to last on future dives. The temp stik reading is not definitive and does not show you in minutes the remaining time. You have to use it like a fuel gauge in your car and know that if you are at depth or working hard then it will not last as long like if you were driving in peak hour city traffic the remaining fuel in your tank will not get you as far. If the black bar is full width and you are planning another dive which won’t be too long, too deep or too hard work then you can go again without changing the sorb. If it shows only a little black bar on the right then it is time to change the sorb. If it shows only one bar and the warning has gone off - it is time to surface and if the warning says the sorb has been totally used up it is time to go open circuit NOW. If I am planning on doing a longer, deeper dive or potentially more risky dive then I will make sure that there will be enough sorb duration remaining for the dive by changing it. And as is prudent I allow enough margin to allow for contingencies and always have enough bail out to go to open circuit if required. BUT - If in doubt throw it out. After a dive I will take the inner sorb cannister out and after leaving the scrubber canister to dry overnight I will seal it back up in a waterproof sealed dry bag or I put it back into the outside canister and seal it using the plugs and cap from Narked@90 (http://www.narkedat90.co.uk/33.html) __________________ Cheers Rod
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10th August 2006, 06:33	#15 (permalink)
mortenkjerulff Customise Me! Current Rebreather/s: Megalodon Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: Denmark Posts: 143	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by Gillenvy) ... perhaps a cogent question would be, has anyone using vision electronics gotten what they think was a co2 hit when the scrubber indicated they were still in the green and if so, under what conditions? Yes. I have seen this happen. Not to me, but to a diver on the same liveaboard. It was on an inspiration, and as far as I remember well within the 3 hour CE-limit and the temp-stick showed no sign of troubles. Water temperature was about 6-8 degrees, and depth about 35 meters. Morten
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10th August 2006, 10:12	#16 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Scurbber duration on Evolution Rebreather Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one! I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else. There are a lot of factors that contribute to the symptoms that people think is a CO2 hit. __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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10th August 2006, 10:38	#17 (permalink)
mortenkjerulff Customise Me! Current Rebreather/s: Megalodon Other Rebreather/s: Not Bought Yet Join Date: Mar 2005 Location: Denmark Posts: 143	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by decoweenie) Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one! I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else. There are a lot of factors that contribute to the symptoms that people think is a CO2 hit. Point taken. But how will one ever know for sure? The symptoms did include headache and fattigue after the dive.
(Online)

10th August 2006, 11:24	#18 (permalink)
MattDuke New Member Current Rebreather/s: Not Bought Yet Other Rebreather/s: Inspiration Classic Not Bought Yet Join Date: May 2006 Location: Bergen, Norway Posts: 24	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by decoweenie) IMHO, the answer is... "2 hours under the worse possible conditions". And that'd be the shortest duration limit since they are not practical test conditions that normally could be repeated in reality. Someone could adhere to this 2-hour limit, and have a lot (and I mean A LOT) of safety. But, IMHO, it is not correct to interpret it as the upper limit. Again, just IMHO... OK, I am a complete novice on CCR, but I thought that by sticking to this limit a diver gives himself a degree of safety for the "Unexpected" Perhaps the surface condtions/current require more exercise than expected. Perhaps the buddy has a problem and you (Righly or wrongly) drop down and try and help. If you stick to the "worse possible conditions" standard for your scrubber, maybe it will save you one day when an unexpected event happens? Perhaps as I get more experienced on CCR I will see my thoughts as very nieve, but for me the simple answer would be. If you need more than 2 hours scrubber, don't by an evo. Whatever unit you buy, stick to the scrubber run time as instructed and hopefully give your self that lucky break if something really bad happens. As I said. Matt=CCR noob. But that's how I see it for my novice position. As always more knowledge may explain why you would overrun a scrubber, but it seems dodgy to me. EDIT: I have been diving by the rule of thirds for so long now OC; that I kinda see the same need on a scrubber, to a lesser extent. When underwater, I don't want any lifesupport system being used to the "Limit". __________________ Born 1975 Started Diving 1984 Started CCR Diving 2006. Stopped CCR Diving 2006. CCR isn't for everyone, but it was a lot of fun trying. Last edited by MattDuke : 10th August 2006 at 11:27.
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10th August 2006, 11:48	#19 (permalink)
Johnny Christensen Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Apr 2006 Location: Denmark Posts: 304	Re: Scurbber duration on Evolution Rebreather Quote: (Originally Posted by decoweenie) Just be careful... Just because someone thinks it is a CO2 hit doesn't necessarily make it one! I have lost count the number of times people claiming a CO2 hit, then after a long discussion, it was something else. There are a lot of factors that contribute to the symptoms that people think is a CO2 hit. Well, it was my buddy it happened to. And in the past I've seen him still being in control of the situation when other people would have run away screaming. So for him to completly loose control of his breathing, there had to be a very good reason. All the "right" conditions where there. Semi rough surface conditions when we jumped in. A bit of current when we pulled us down. He used only his ADV to supply gas on the way down, thereby having a bit higher WOB compared to manual gas addition when you are a adding gas before you bottom out on the CL. We went against a mild current on the wreck, he was less streamlined than I was. I ducked down to the stern of the wreck, to get out of the current and relax. He never made it so far and had to return by current to the shotline. I missed that part and started searching at the bottom of the wreck, where I expected to find him on the opposite side. Meanwhile he was flushing the unit and going back to the shotline. At the time where he was there again, his breath was so out of control that he could only look at the OC bailout reg he was holding in his hand, but in no way perform the switch. He looked at the scrubber gauge and it told him that everything was just fine... For some kind of reason, he did not quite believe that. Afterwards he had a headache, and had to take a couple of hours in his bunk. He reported that while it went on, he had a very rapid heart rate. Scrubber use was 2 hrs 45 min. GolemGear BOV is to be fitted as soon as it arrives __________________ www.johnnychristensen.com Wreckphotography from the cold north
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10th August 2006, 13:10	#20 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Scurbber duration on Evolution Rebreather Johnny, In the context of the current discussion, it sounds more like your buddy got winded from the heavy work. And over-breathed the loop rather than a scrubber exhaustion. __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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