Carbon Monoxide tank risks and protections .
- Thread starter DandyDon
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OP
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Ah, that one. I called the original manufacturer when I first got interested, but he had stopped making them. He used to use a yoke attachment so you could blow air thru it for 5 or 10 minutes.
I guess they brought it back when they saw Analox introduce their unit. The balloon approach is better, but still - 5 to 10 minutes for a color code vague idea? I suspect a lot of balloons will get lose and fly overboard, others break, etc. And then there is their warning...
But try it if you'd like. Not much invested to see...
My Analox gives me a final reading in 30 seconds, then on to the next tank.
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It came Friday. Now you're going to freak out a bit here so ... The reason I bought it is because I own a Coltri gas engine compressor. :crazyeye: So for me, testing is a must. Right away I tested a tank that was filled at the local dive shop. Big fat "0". I then tested one I filled to 3600 from 1000 pounds. I watched the detector in the bag, and after about 3 minutes, it did finally register a "1" after toggling back and forth from 0 to 1 for a while.
Here's the scary part. I put the detector at the air intake while filling a tank, and it eventually registered a 24. So I will be ordering an intake extension tube for my unit tomorrow. Obviously the filtration is working, but I don't want to depend on it. I will be continuing to test.
Oh and as for the unit, it is fine for what I'm doing. Would I use it to test every tank on a boat? No way. But for what I'm doing, it seems to be fine. Thanks for all the information you are sharing on this.
Mr. Willoughby
Contributor
After reading this thread and some of the incidents in the A&I forum I am seriously considering getting one of the Analox units. I'll see if my LDS can get a good price on them the next time I'm in.
Dr. Lecter
Contributor
There was a group buy through Scubatoys at around $283 per unit earlier this year. Perhaps enough interest could be generated to do another one?
manni-yunk
Contributor
I have the Analox Co tester and use it religiously. I have my own compressor and I test every tank I fill. I also bring it when I get fills from dive shops, dutch, on trips, etc.
So far - Ive almost always had a ZERO reading. On my compressor - Ive never had anything other than zero. Every once in a while I get a 1 from someoen elses compressor. I recently came across a fill (not my fill) that was a 14. At first I though that the tester might be failing. So I tested a few other tanks filled by the same compressor - readings from 4 - 14. I recallibrated and tested again - same reading.
Turns out that a gas compressor had a snorkel that had come loose at a connection right above the engine exhaust.
I know those readings might not be to bad - but - thanks to the tester - the connection was immediately fixed and tanks refilled with better readings.
I think the CO tester is as important as my O2 tester. I like the Analox so much that Im strongly leading towards their He tester as well.
So far - Ive almost always had a ZERO reading. On my compressor - Ive never had anything other than zero. Every once in a while I get a 1 from someoen elses compressor. I recently came across a fill (not my fill) that was a 14. At first I though that the tester might be failing. So I tested a few other tanks filled by the same compressor - readings from 4 - 14. I recallibrated and tested again - same reading.
Turns out that a gas compressor had a snorkel that had come loose at a connection right above the engine exhaust.
I know those readings might not be to bad - but - thanks to the tester - the connection was immediately fixed and tanks refilled with better readings.
I think the CO tester is as important as my O2 tester. I like the Analox so much that Im strongly leading towards their He tester as well.
DandyDon, A big thanks for all your effort, extensive writings and concern for the safety of our diving community. Learning through your discussions I also purchased an Analox CO tester. My typical diving is the West Palm Beach area of FL were the profile is 2-3 dives to 80-90'. Over the last year of testing every tank I've found only one instance of 2 tanks with 3 ppm CO.
This last week I picked up my 2 - Steel 100s and discovered 11 ppm in each. Normally, I will test the tanks before filling and right after. My mistake this day was to test the of morning of the dive, 140 miles from the filling dive shop. I made a call back to inform the owner of the issue. He was concerned yet couldn't figure how it might of happened, his equipment tested fine on the last inspection and has inline filters/alarms.
This reaffirms your point, CO poisoning could happen at any time from any dive store, even those in the USA that regularly test, have CO filters/alarms. It's our lives at risk and it's only smart to mitigate out this through a decent tester. My two buddies diving with me saw first hand what can happen and now are believers.
Keep up the good work, and again thanks!
This last week I picked up my 2 - Steel 100s and discovered 11 ppm in each. Normally, I will test the tanks before filling and right after. My mistake this day was to test the of morning of the dive, 140 miles from the filling dive shop. I made a call back to inform the owner of the issue. He was concerned yet couldn't figure how it might of happened, his equipment tested fine on the last inspection and has inline filters/alarms.
This reaffirms your point, CO poisoning could happen at any time from any dive store, even those in the USA that regularly test, have CO filters/alarms. It's our lives at risk and it's only smart to mitigate out this through a decent tester. My two buddies diving with me saw first hand what can happen and now are believers.
Keep up the good work, and again thanks!
OP
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Thanks for sharing that experience. Some might question just how bad 11 ppm could be, even at depth - but the risk process is complicated, plus you have to wonder - if that got thru, what else might have. The filler seems sincere enough, and you have to wonder how it happened - but it happens.
bongabonga
Registered
I purchased analox analyzer after my gf told me that she got headache for a week after diving a bad fills...
I agree that we can't be too careless about CO...
I will go diving next week in Bali, I will post the trip CO reading on this thread
I agree that we can't be too careless about CO...
I will go diving next week in Bali, I will post the trip CO reading on this thread
swamp diver
Contributor
I think what this thread is beginning to confirm with the number of CO contaminated tanks identified over the last few months is exactly what the accredited compressed breathing air laboratories have been saying for the last decade which is that 3% to 5% of "dive" air samples sent to them are contaminated with CO which is a failure rate that is exceedingly high.
When asked the same question about US fire service compressed air quality these same laboratories will tell you that about 0.1% to 0.3% of samples sent to them fail on carbon monoxide so we have a significant problem in the dive industry with respect to compressed breathing air quality.
These are sample failures with CO concentrations > 10 ppm.
The CO contamination is usually from one of three sources:
1) Exhaust from internal-combustion engine driving compressor
See post #43 above, the Maldivian CO fatality, etc.
There can be leaks in the snorkel-inlet connection as above, holes or cracks in the compressor snorkel as in the Maldivian fatality incident, or simply poor placement of the snorkel relative to exhaust outlet.
The most dangerous conditions are the windless days since the exhaust plume travels horizontally along the ground and upwards.
Many portable fire service compressors are at the back of the truck with the intake up and above the cab. Even with this compressor inlet-exhaust outlet separation, on windless days testing has shown that the CO plume will show up at the intake after a sufficient interval of time. I know several fire services that now hang a CO monitor at the inlet with a 95 dB alarm for this reason.
2) Exhaust entrained from vehicular or boat traffic
One need only look at the compressor intake location and determine if a car, truck, boat, gas furnace, or BBQ exhaust could get into the intake. I inspect the intake location for each and every compressor I use. A few years back I came across a compressor inlet 36 inches from the exhaust outlet for the building's gas furnace and routinely see dive compressor inlets above or close to where boats are idling.
3) Carbon monoxide produced within an electric compressor.
This is the most common source of CO according to the compressed air laboratories. The compressor is typically located in a high temperature ambient environment, poorly installed with insufficient cooling, and often running a mineral oil or worse with a low auto-ignition point. Many of these tropical compressors are not running a catalyst bed in the filter used to convert CO to less harmful CO2 so any CO produced will go straight into the fill or banks.
Be very leery of a compressor in a very tight space with the intake fan jammed up against the wall. Most compressors require a hole in the wall with access to cooler intake air, or at least one meter (36 inches) of space between the intake fan and wall.
The take home message is to check each and every tank with a CO analyzer prior to use and to be aware that electrically-driven compressors can and do produce CO from within by burning (dieseling) the compressor's lubrication oil.
Be extremely cautious if purchasing compressed breathing air produced by an internal-combustion engine driven compressor.
Always check the location of the compressor inlet and whether or not a vehicle's or boat's exhaust could get access to it.
When asked the same question about US fire service compressed air quality these same laboratories will tell you that about 0.1% to 0.3% of samples sent to them fail on carbon monoxide so we have a significant problem in the dive industry with respect to compressed breathing air quality.
These are sample failures with CO concentrations > 10 ppm.
The CO contamination is usually from one of three sources:
1) Exhaust from internal-combustion engine driving compressor
See post #43 above, the Maldivian CO fatality, etc.
There can be leaks in the snorkel-inlet connection as above, holes or cracks in the compressor snorkel as in the Maldivian fatality incident, or simply poor placement of the snorkel relative to exhaust outlet.
The most dangerous conditions are the windless days since the exhaust plume travels horizontally along the ground and upwards.
Many portable fire service compressors are at the back of the truck with the intake up and above the cab. Even with this compressor inlet-exhaust outlet separation, on windless days testing has shown that the CO plume will show up at the intake after a sufficient interval of time. I know several fire services that now hang a CO monitor at the inlet with a 95 dB alarm for this reason.
2) Exhaust entrained from vehicular or boat traffic
One need only look at the compressor intake location and determine if a car, truck, boat, gas furnace, or BBQ exhaust could get into the intake. I inspect the intake location for each and every compressor I use. A few years back I came across a compressor inlet 36 inches from the exhaust outlet for the building's gas furnace and routinely see dive compressor inlets above or close to where boats are idling.
3) Carbon monoxide produced within an electric compressor.
This is the most common source of CO according to the compressed air laboratories. The compressor is typically located in a high temperature ambient environment, poorly installed with insufficient cooling, and often running a mineral oil or worse with a low auto-ignition point. Many of these tropical compressors are not running a catalyst bed in the filter used to convert CO to less harmful CO2 so any CO produced will go straight into the fill or banks.
Be very leery of a compressor in a very tight space with the intake fan jammed up against the wall. Most compressors require a hole in the wall with access to cooler intake air, or at least one meter (36 inches) of space between the intake fan and wall.
The take home message is to check each and every tank with a CO analyzer prior to use and to be aware that electrically-driven compressors can and do produce CO from within by burning (dieseling) the compressor's lubrication oil.
Be extremely cautious if purchasing compressed breathing air produced by an internal-combustion engine driven compressor.
Always check the location of the compressor inlet and whether or not a vehicle's or boat's exhaust could get access to it.
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