How long can absorbent be stored?!

Barrie Law · 10th February 2007, 11:34

Quote: (Originally Posted by bourskov)

Hi out there...

We are two new Rebreather divers, and we have discussed an issue about absorbent. The question is, for how long can you store absorbent in a scrubber, before it's gone bad?

Example: I've packed my scrubber today, and used 30 mins (5 degrees Celsius is cold for longer times

) and after the dive, I took my unit apart for cleaning. My scrubber will be in normal air until tomorrow (to get some of the moisture out), where I'll put it in an plastic bag and make it airtight, more or less.

So, is there a rule of thumb about how long it's still safe to dive a used and stored scrubber?!

Don't think of this post as a way to compromise safety, but I just think it is stupid to throw away absorbent, if it's stil usable...

Best regards...
Bo Urskov

Hi Bo,

As you can see opinions differ regarding the amount of time or even the method for storing sofnolime.

I have used the following rational over the years;

If I have dived the unit and the sofno is still be good I will use it for the next dive providing that is within 24 Hours.

If the next dive is after 24 Hours I would bin it and use fresh sofnolime partly because I would be prepping the unit from scratch but also if I dive the sofno after 24 Hours a little voice in the back of my head will be casting doubts on the scrubber during the whole dive and I am there to enjoy myself not to be worrying about the "Dodgy" sofnolime during the dive.

That said most of my dives these days require a scrubber change after every dive so it's not really an issue for me.

Regards

PacketSniffer · 10th February 2007, 11:56

Quote: (Originally Posted by bourskov)

So, is there a rule of thumb about how long it's still safe to dive a used and stored scrubber?!

I've been taught that one week is acceptable if stored in a sealed bag in a cool environment.

It's fine to leave the moisture in the absorbent canister if you have just made a dive. Personally, I wouldn't let the absorbent canister dry out overnight. I would seal it in a bag right away. The chemical reactions will eventually stop in the absense of heat. However, I would allow the plenum (the can) to dry out.

jptaylor9 · 10th February 2007, 12:00

Quote: (Originally Posted by Barrie Law)

little voice in the back of my head will be casting doubts on the scrubber during the whole dive

One of the benefits of the Temp Stik, you do have some visual data on that it's doing (bit off topic I know). Not suggesting you push the scrubber because of the temp stik.

Dutchy · 10th February 2007, 12:25

Quote: (Originally Posted by PacketSniffer)

The chemical reactions will eventually stop in the absense of heat

No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate.
I wouldn't leave it out that long though

PacketSniffer · 10th February 2007, 13:48

Quote: (Originally Posted by Dutchy)

No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate.
I wouldn't leave it out that long though

Ok, maybe in a week the chemical reaction is still going, albeit barely, smarty pants.

Thanks for the info.

jptaylor9 · 10th February 2007, 13:52

Quote: (Originally Posted by Dutchy)

No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate.
I wouldn't leave it out that long though

I think you just made my point for me

**fireman** · 10th February 2007, 14:01

sorb=cheep, life=priceless...Why mess around.

***EBT*** · 10th February 2007, 14:03

cheep=canary. Might be useful as a CO2 detector.

PacketSniffer · 10th February 2007, 14:30

I don't see anything cheap about it. The practice of saving a 1/4 used canister for the next weekend (on a easy dive) is a practice that is being employed successfully without any issue. If it was to be a deep or strenuous dive, well, duh, change it.

jaap · 10th February 2007, 14:37

Obviously the best is to follow the recomendations from the manufacturer (of the sorb and the unit)...

But...I have dived sorb that was most probably stored for 33 years in the scrubber attached to the unit. It worked just fine. The fill date was from the paper filling protocol attached to the cannister.

But it was in warm water, shallow (O2-Rebreather) and I did a few minutes of pre breathing.

I normally store my sorb in the scrubber if I think I will use it in a few weeks time and it has not already been used up to much. If the sorb is very wet I toss it out (like from some flooding). If its somewhat wet I might leave the scrubber open overnight or so to dry it a bit.

I belive that very dry sorb is _very_ dangerous if the user does not perform a long prebreathing (>5min) to moisen the sorb and get a chance to feel if its working OK.

I don't worry to much about the CO2 in the air sneaking in and recting with the sorb. Storage temperature is normally a lot lower compared to the
working temp of the scrubber and the CO2 conc in air is low (like 0.03-0.07 %). All this makes for a very slow sorb consumption.

And besides since there is normally no flow of air into the scrubber that also hinders the sorb consumption.

10th February 2007, 11:34	#11 (permalink)
Barrie Law RebreatherWorld Sponsor Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jun 2005 Location: Ireland Posts: 726	Re: How long can absorbent be stored?! Quote: (Originally Posted by bourskov) Hi out there... We are two new Rebreather divers, and we have discussed an issue about absorbent. The question is, for how long can you store absorbent in a scrubber, before it's gone bad? Example: I've packed my scrubber today, and used 30 mins (5 degrees Celsius is cold for longer times ) and after the dive, I took my unit apart for cleaning. My scrubber will be in normal air until tomorrow (to get some of the moisture out), where I'll put it in an plastic bag and make it airtight, more or less. So, is there a rule of thumb about how long it's still safe to dive a used and stored scrubber?! Don't think of this post as a way to compromise safety, but I just think it is stupid to throw away absorbent, if it's stil usable... Best regards... Bo Urskov Hi Bo, As you can see opinions differ regarding the amount of time or even the method for storing sofnolime. I have used the following rational over the years; If I have dived the unit and the sofno is still be good I will use it for the next dive providing that is within 24 Hours. If the next dive is after 24 Hours I would bin it and use fresh sofnolime partly because I would be prepping the unit from scratch but also if I dive the sofno after 24 Hours a little voice in the back of my head will be casting doubts on the scrubber during the whole dive and I am there to enjoy myself not to be worrying about the "Dodgy" sofnolime during the dive. That said most of my dives these days require a scrubber change after every dive so it's not really an issue for me. Regards __________________ Barrie Law Rebreather World Store Supplying the Rebreather World Tel:US +19548403892 Fax:US+19543333792 Tel:EU+442071930496 Fax:EU+442077606344 Mobile+353876880628 Skype:barrielaw Email: barrie@rebreatherworldstore.com
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10th February 2007, 11:56	#12 (permalink)
PacketSniffer ~~~~~ #417 ~~~~~ Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2006 Location: Houston Posts: 437	Re: How long can absorbent be stored?! Quote: (Originally Posted by bourskov) So, is there a rule of thumb about how long it's still safe to dive a used and stored scrubber?! I've been taught that one week is acceptable if stored in a sealed bag in a cool environment. It's fine to leave the moisture in the absorbent canister if you have just made a dive. Personally, I wouldn't let the absorbent canister dry out overnight. I would seal it in a bag right away. The chemical reactions will eventually stop in the absense of heat. However, I would allow the plenum (the can) to dry out. __________________ Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.
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10th February 2007, 12:00	#13 (permalink)
jptaylor9 Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: London, UK Posts: 318	Re: How long can absorbent be stored?! Quote: (Originally Posted by Barrie Law) little voice in the back of my head will be casting doubts on the scrubber during the whole dive One of the benefits of the Temp Stik, you do have some visual data on that it's doing (bit off topic I know). Not suggesting you push the scrubber because of the temp stik. Last edited by jptaylor9 : 10th February 2007 at 17:20.
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10th February 2007, 12:25	#14 (permalink)
Dutchy Rene Warries Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Nieuwegein (The Netherlands) Posts: 763	Re: How long can absorbent be stored?! Quote: (Originally Posted by PacketSniffer) The chemical reactions will eventually stop in the absense of heat No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate. I wouldn't leave it out that long though __________________ = This post is environmentally friendly. It is composed of 100% recycled electrons only. =
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10th February 2007, 13:48	#15 (permalink)
PacketSniffer ~~~~~ #417 ~~~~~ Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2006 Location: Houston Posts: 437	Re: How long can absorbent be stored?! Quote: (Originally Posted by Dutchy) No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate. I wouldn't leave it out that long though Ok, maybe in a week the chemical reaction is still going, albeit barely, smarty pants. Thanks for the info. __________________ Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.
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10th February 2007, 13:52	#16 (permalink)
jptaylor9 Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: London, UK Posts: 318	Re: How long can absorbent be stored?! Quote: (Originally Posted by Dutchy) No it won't. The chemical reaction goes at every temperature! But at room temperature it is very slow. (as a rule of thumb 2 times slower per three degrees celcius resulting in an approximate 2^10 = approx 1000 times slower) Given that the concentration of CO2 in ambient air is lower as well (thus slowing reaction speed) makes it safe to assume that is still a conservative estimate. I wouldn't leave it out that long though I think you just made my point for me
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10th February 2007, 14:01	#17 (permalink)
fireman rEvo combat swimmer Current Rebreather/s: rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Nov 2006 Location: chicago Posts: 526	Re: How long can absorbent be stored?! sorb=cheep, life=priceless...Why mess around.
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10th February 2007, 14:03	#18 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,995	Re: How long can absorbent be stored?! cheep=canary. Might be useful as a CO2 detector. __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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10th February 2007, 14:30	#19 (permalink)
PacketSniffer ~~~~~ #417 ~~~~~ Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jun 2006 Location: Houston Posts: 437	Re: How long can absorbent be stored?! I don't see anything cheap about it. The practice of saving a 1/4 used canister for the next weekend (on a easy dive) is a practice that is being employed successfully without any issue. If it was to be a deep or strenuous dive, well, duh, change it. __________________ Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.
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10th February 2007, 14:37	#20 (permalink)
jaap Normal people worry me Current Rebreather/s: Classic Kiss Other CCR RB80 / Clone Ray Other SCR Home Build Other Rebreather/s: Other CCR RB80 / Clone Ray Other SCR Home Build Join Date: Jun 2005 Location: Stockholm Sweden Posts: 451	Re: How long can absorbent be stored?! Obviously the best is to follow the recomendations from the manufacturer (of the sorb and the unit)... But...I have dived sorb that was most probably stored for 33 years in the scrubber attached to the unit. It worked just fine. The fill date was from the paper filling protocol attached to the cannister. But it was in warm water, shallow (O2-Rebreather) and I did a few minutes of pre breathing. I normally store my sorb in the scrubber if I think I will use it in a few weeks time and it has not already been used up to much. If the sorb is very wet I toss it out (like from some flooding). If its somewhat wet I might leave the scrubber open overnight or so to dry it a bit. I belive that very dry sorb is _very_ dangerous if the user does not perform a long prebreathing (>5min) to moisen the sorb and get a chance to feel if its working OK. I don't worry to much about the CO2 in the air sneaking in and recting with the sorb. Storage temperature is normally a lot lower compared to the working temp of the scrubber and the CO2 conc in air is low (like 0.03-0.07 %). All this makes for a very slow sorb consumption. And besides since there is normally no flow of air into the scrubber that also hinders the sorb consumption. __________________ My initials: JAAP
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