Carbon Monoxide tank risks and protections .

[tamas970]

I see threads growing on the topic for years, and so far I saw only detectors mentioned. Is there any CO burning catalysts/CO trapping filter (e.g. hopcalite) units, that could be simply screwed on the regualtor hose?

Honestly, as an engineer, I don't trust much devices measuring at their detection limit... 5ppm could already be too much for certain individuals (low body weight+deep dive with 15L air) - if that can be reduced to 1, it can be a lifesaver. Also, if a smoked 100ppm bottle can be safely reduced to 20, the diver wouldn't die... The life/death question is the total CO dose. If a filter can capture large amounts of CO during ~80% of the dive and saturates during ascent, the fellow's life is saved. At the end, a color change (such in case of the CO-PRO disk) indicates, that the filter should be recharged.

Come on, confirmed CO-poisoning fatalities, like this cannot make a change in the industry?:

Rebreather Pro: Report on Mexico Rebreather Fatality

Firefighters and miners use these kind of units, why isn't it available for diving? The only thing to do, is to copy this unit:

http://www.fireengineering.com/arti...ir-emergency-using-technology-to-survive.html

(filter with Active coal and hopcalite - for diving, a layer of desiccant has to be added as well. Raw material costs should be below 50$ including inox or brass housing...)

 

[Ayisha]

Honestly, as an engineer, I don't trust much devices measuring at their detection limit... 5ppm could already be too much for certain individuals (low body weight+deep dive with 15L air) - if that can be reduced to 1, it can be a lifesaver.

Tamas, some CO analyzers have no blanked out band and can detect even 1 ppm CO. For example, the Toxi Rae 3 can detect 0 - 500 ppm; the Oxycheq Expedition can detect 0 - 100 ppm; and the Analox EII can detect from 1 - 50 ppm (or beyond as seen elsewhere). Most of those figures are a couple of years old, and may have changed, but those units are all very sensitive.

Is there any CO burning catalysts/CO trapping filter (e.g. hopcalite) units, that could be simply screwed on the regualtor hose?...If a filter can capture large amounts of CO during ~80% of the dive and saturates during ascent, the fellow's life is saved.

Hopcalite, in the presence of oxygen in a dry environment, catalyzes (converts) the Carbon Monoxide into less deadly CO2. I don't think that CO is mechanically filtered out because CO and O2 molecules are too similar, correct me if I'm wrong. It would be awesome though.

 

[tamas970]

Tamas, some CO analyzers have no blanked out band and can detect even 1 ppm CO. ....

I have yet to find an equivalent european version... (or take a diving holiday in US soil)
Over here the Greisinger GCO 100 is advertised as "diver's CO detector" but I am not much fun of its "0-1000ppm range" and 5ppm error limit. (Meaning the real CO content is 10ppm and you see 5 and decide to join the dive).

The TPI 770 seems to get closer to my expectations but I have to do some more research. l like it's price, I don't want to pay 400€ for something, that can be solved with 100.

Hopcalite, in the presence of oxygen in a dry environment, catalyzes (converts) the Carbon Monoxide into less deadly CO2. I don't think that CO is mechanically filtered out because CO and O2 molecules are too similar, correct me if I'm wrong. It would be awesome though.

You are exactly right, I should have wrote that (especially that I am a chemical engineer ) Anyway, I am not worried about 10, 100 even 1000ppm CO2 produced by CO combustion.

 

[DandyDon]

I have yet to find an equivalent european version... (or take a diving holiday in US soil)

Your profile doesn't say where you are. Germany? Finding equivalent brands and international shipping and customs can get pricey I know. We have an exchange student from Berlin whose dad is a physician, and when the boy came down with a head cold - the dad told us what nose drops to get him, except it's not available here. I suggested Actifed, still easily available without script in Texas, but my daughter compromised on some OTC drops. I doubt that they helped much, but he's young and survived easily enough.

Analox is a European brand tho, headquartered in the UK not far from Middlesbrough and the English Channel, so I wouldn't think it'd be too difficult to get on the mainland? I am such a fan that some have thought I was involved. I am not in the least, but the company has really come to our aid well in this area, the unit's sensor is designed to be accurate in low ranges as well as fast, small & easy to use, even water resistant. With its field calibration knob, you can really dial in accurate comparisons. We use non-smoker human breath to test it for still working, altho a smoker's breath can give bigger results.

Over here the Greisinger GCO 100 is advertised as "diver's CO detector" but I am not much fun of its "0-1000ppm range" and 5ppm error limit. (Meaning the real CO content is 10ppm and you see 5 and decide to join the dive).

EASYBUS Datenlogger Greisinger electronic GmbH It looks like it's designed for building heater and fireman inspections, as you said - high ranged. It claims an accuracy for 5% but as you said only 5ppm in lower ranges so while better than not testing for a dive tank, not really what we want.

The TPI 770 seems to get closer to my expectations but I have to do some more research. l like it's price, I don't want to pay 400€ for something, that can be solved with 100.

It looks interesting, another UK product, but high ranged and accurate ±3ppm or 5% (whichever is the greater). Got to wonder how large it is to carry around and how easily it works on tanks. $130 GBP is more like $211 USD, by the way and just not as accurate as we want.

You are exactly right, I should have wrote that (especially that I am a chemical engineer ) Anyway, I am not worried about 10, 100 even 1000ppm CO2 produced by CO combustion.

No, CO2 is relatively harmless in comparison so using such a filter on a compressor is a good idea. It might work on a diver's reg, but I'd still want to test each and every tank - and once doing so, not really see the point of having the filter. If a tank has a positive CO reading, I am going to wonder what else they let in so wouldn't dive it even with such a filter.

 

[Ayisha]

Tamas, the Oxycheq Expedition has an accuracy of +/- 2 ppm, so it's a little closer to your ideal. Not sure if that one works for you, but Oxycheq is a very respected brand in hand-held oxygen and helium analyzers and other equipment.

 

[swamp diver]

I have yet to find an equivalent european version... (or take a diving holiday in US soil)
Over here the Greisinger GCO 100 is advertised as "diver's CO detector" but I am not much fun of its "0-1000ppm range" and 5ppm error limit. (Meaning the real CO content is 10ppm and you see 5 and decide to join the dive).

Contact Analox in Germany or whatever country you are in. Here are their contacts for Europe. The Analox CO EII has a minimum detection limit of 1 ppm and a resolution of 1 ppm. Plenty accurate for our diving needs and it is calibrated using a 10 ppm CO span gas so the linearity in the 0 to 10 ppm range is excellent.
Sport Distributors in Europe
[url]http://www.aquanauts.co.uk/accessories/analox-eii-co-carbon-monoxide-analyser
[/URL]

 

[tamas970]

I just did a bit more research and figured, that most (all fuel-cell based?) CO-analyzers need sensor replacement in 3 years. In case of the analox, this adds 158$ (+~50$ shipping& customs for me) to the initial cost every 2-3 years is quite costly (yearly ~70$ plus device price).

Even worse, the setup has to be properly calibrated after sensor replacement (=either by sending back to supplier or buying a standard CO sample). At the end, we approach the cost of a new analyzer...

Unfortunately, the budgeting of the Oxycheck is similar (Initial price: 450$, replacement sensor: 140$)

I feel, the market really needs a user-friendly solution. Practically paying 2-300+$ every 3 years is not being one for doing the job of the Dive center...

 

[swamp diver]

Having used the Analox compressor monitors for over 4 years now with a similar (not identical) sensor to the EII CO I can say the sensor will likely last at least 4 years possibly five.

Your local distributor should be able to calibrate the unit when a new sensor is purchased and if not Analox UK is not far away. So assuming a 4 year sensor life your annual cost will be in the ball park of $160. If you have a regular buddy you could split the cost with him or her.

You might want to reflect on the 8 divers that I know of who have died from CO-contaminated breathing gas over the last 7 years and what their answer would be if asked about an annual cost of $160 to ensure their breathing gas was CO-free?

 

[tamas970]

That 8 is exactly 8 too many And how many are there that we don't know?

I don't take compromise in terms of measurement-capabilities: the device has to measure reliably in the
1-10ppm range with max 2ppm error. I'd say I refuse tanks over 5ppm reading - worst case: real concentration 7ppm (5+error), at 120' this is equivalent to 35ppm, borderline of the dangerous territory: Air Quality: Carbon monoxide, a deadly gas.

Where I am ready to make some compromise is confort of use and response time (within reasonable limits...) if there is a significant discount in price. If the Pocket CO specifications are right, I don't have to give up accuracy, just need to take a bit more care of the unit and wait a little longer to the result.

BTW I haven't given up hope for a personal CO filter, new catalyst candidates are emerging:
http://www.saimm.co.za/Conferences/WorldGold2009/259-264_McPherson.pdf
Key points:
->Not sensitive to humidity (unlike Hopcalite),
->More efficient than hopcalite & co.
->resistance to deactivation - here there is some more development to do, the author's cigarette concept deactivated in 2 weeks. This cigarette concept gives me hope, if the tobacco industry puts some money in
the project, the only thing we have to do is to upgrade an Apollo bio filter with a nano-gold cigarette filter.

Having used the Analox compressor monitors for over 4 years now with a similar (not identical) sensor to the EII CO I can say the sensor will likely last at least 4 years possibly five.

Your local distributor should be able to calibrate the unit when a new sensor is purchased and if not Analox UK is not far away. So assuming a 4 year sensor life your annual cost will be in the ball park of $160. If you have a regular buddy you could split the cost with him or her.

You might want to reflect on the 8 divers that I know of who have died from CO-contaminated breathing gas over the last 7 years and what their answer would be if asked about an annual cost of $160 to ensure their breathing gas was CO-free?

 

[DandyDon]

That 8 is exactly 8 too many And how many are there that we don't know?

I don't take compromise in terms of measurement-capabilities: the device has to measure reliably in the
1-10ppm range with max 2ppm error. I'd say I refuse tanks over 5ppm reading - worst case: real concentration 7ppm (5+error), at 120' this is equivalent to 35ppm, borderline of the dangerous territory: Air Quality: Carbon monoxide, a deadly gas.

Where I am ready to make some compromise is confort of use and response time (within reasonable limits...) if there is a significant discount in price. If the Pocket CO specifications are right, I don't have to give up accuracy, just need to take a bit more care of the unit and wait a little longer to the result.

The ones we don't know about, the hits survived but not reported, the "travelers flu" cases from less serious hits. And it's not just the equivalent to 35 ppm that I worry about, but also the way CO binds with blood and hits you harder on ascent while PPO is dropping. Besides, if a compressor allows 5 ppm CO in, what else is getting in?

The Pocket CO300 will work, with the limitations and cautions I offered in the other thread: http://www.scubaboard.com/forums/basic-scuba-discussions/414866-competition-co-analyzer-market.html My first one did not start reading until 5ppm, while my replacement started at 3ppm, and I think it's accurate from there. I used to wear mine to cafes, on planes, etc.

BTW I haven't given up hope for a personal CO filter, new catalyst candidates are emerging:
http://www.saimm.co.za/Conferences/WorldGold2009/259-264_McPherson.pdf
Key points:
->Not sensitive to humidity (unlike Hopcalite),
->More efficient than hopcalite & co.
->resistance to deactivation - here there is some more development to do, the author's cigarette concept deactivated in 2 weeks. This cigarette concept gives me hope, if the tobacco industry puts some money in
the project, the only thing we have to do is to upgrade an Apollo bio filter with a nano-gold cigarette filter.

Technology is a wonderful thing.