co2 - safe handling?
Just got myself a co2 tank designed to fill small paintball tanks.
I plan to use this mostly for combat robotics and possibly for a MIG set up when I get MIG. I do have SCUBA experience, an air compressor and a TIG set up. But co2 seems to be a bit of a different horse as it is stored in liquid form. Looking for information sources on handling this safely. Favorite books, web sites, free advice... Tanks :-) for any help. DOC |
co2 - safe handling?
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co2 - safe handling?
Just got myself a co2 tank designed to fill small paintball tanks.
I plan to use this mostly for combat robotics and possibly for a MIG set up when I get MIG. Did you get one for paintball filling or for welding? the paintball unit has a tube inside the tank so liquid comes out when its upright, can't be used to weld. A weld tank has to be upside down to dispense liquid. a small tube and valve kit is sold to hook the paintball tank up to the big tank. Comes with directions. basically you vent a little gas out of the paintball can and the pressure difference forces liquid across. Biggest issue with filling is freezing a line up - go slow. DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled paintball tanks for all his friends when he was home. He overfilled one and, not knowing of a problem, put it in the car and started driving. It popped the relief valve with a bang while they were driving. They almost had an accident trying to jump out of the car cause they thought a bomb had went off. Karl |
co2 - safe handling?
Newshound wrote:
Not quite the only issue. Even a CO2 tank in a fire is a bomb,... I don't think so - they have pressure relief valves. Plugs, actually, IIRC. And if you happen to have confined spaces, particularly a cellar or similar, there is a real asphyxiation risk from a leak. ... I don't think so - breathing just a little would be so distressing that you'd immediately get-the-hell-out. It's the rise in CO2 concentration in our lungs that makes it so hard to hold your breath for very long. There's still plenty of oxygen in your lungs but the rising CO2 says: BREATH! BREATH!! You start experiencing that in your cellar and you'll be out of there long before asphyxiation is a risk. Bob |
co2 - safe handling?
Hi Bob,
My experience has been a bit different to yours. Regarding CO2 cyllinders as a potential source of explosions, about 3 weeks ago my best friend was in his caravan when it caught on fire. he had a mid size co2 cyllinder inside, which ruptured. The temperature was extremely hot inside the van, hot enough that it melted all the aluminum sheeting. The cyllinder ruptured in an unusual way, splitting right down the side. It blew through the relatively thin wall and landed about 30 feet away on the road. I was outside the van trying to get in when it exploded. the safety release valve did not operate, there is a current investigation being made by BOC as to why. Regarding risk of asphyxiation, this is a very real risk. I work in mount isa australia, a fairly large mining town. The company i work for is frequently doing confined spaces work inside tanks and other vessels. we follow standard procedures of using forced fan ventillation and extraction, an air sniffing machine and having a spotter who is qualified to do a confined spaces recovery in case of the worst. We have thankfully never experienced an incident, but we do receive safety bulletins from other companies as part of our safety network. I have seen quite a few bulletins concerning deaths in these types of situations. One particular case that comes to mind ivolved the death of 3 people - the person in the confined space, and the deaths of two people trying to recover him. We did have a near miss last year while welding inside a copper smelting pot. These pots are used by the mine and hold about 90 tonnes of copper. You climb up a ladder to get inside, its like sitting in a giant coffee cup. We weld tham back up with a dual shield filler with CO2 as the gas. The two staff welding the pot had gone for lunch and had turned off the extraction system for some peace and quiet. What had happened was the valve on the welding unit which controls the gas flow had stuck 'on'. gas was continuously pouring out the end of the nozzle at 20 litres a minute. They had a fairly long lunch and there wasnt much wind blowing that day. the Co2 filled up the copper pot much like water - displacing all the breathable air. The guys came back, and the welder climbed into the pot while the other fellow went to turn the extractor back on. once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. Thankfully the extractor system came on and fresh air was forced inside. It was a big wake up call for us. Ive never actually breathed Co2 myself, though i have done my share of confined spaces welding. Im very concerned about following the right procedures for this type of work. Best Regards, Shaun "Bob Engelhardt" wrote in message . .. Newshound wrote: Not quite the only issue. Even a CO2 tank in a fire is a bomb,... I don't think so - they have pressure relief valves. Plugs, actually, IIRC. And if you happen to have confined spaces, particularly a cellar or similar, there is a real asphyxiation risk from a leak. ... I don't think so - breathing just a little would be so distressing that you'd immediately get-the-hell-out. It's the rise in CO2 concentration in our lungs that makes it so hard to hold your breath for very long. There's still plenty of oxygen in your lungs but the rising CO2 says: BREATH! BREATH!! You start experiencing that in your cellar and you'll be out of there long before asphyxiation is a risk. Bob |
co2 - safe handling?
On Aug 17, 4:38 pm, "Pete C." wrote:
.... SCUBA tanks are a lot higher pressure than CO2. The only real issue with CO2 is the potential for frostbite if you manage to release it in liquid form on yourself. Just download the MSDS from the Airgas site. I recall the air tanks were around 3000 PSI and gather that co2 is somewhere around the 600 mark. And I gather that the co2 stays at a constant pressure as long as there is liquid in the tank. That sound right? And paintball tanks are loaded by weight, not pressure. So there's no point in putting a gage on a tank? DOC |
co2 - safe handling?
Shaun Van Poecke wrote:
... The cyllinder ruptured in an unusual way, splitting right down the side. ... the safety release valve did not operate, ... ... the Co2 filled up the copper pot ... the welder climbed into the pot ... once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. ... Shaun - thanks for the real-world input. Too many of our posts are speculation, sometimes not based on much knowledge. While accepting that CO2 is more dangerous than I believed, I'm still going to store my cylinder in the cellar. It's a probability thing (like most things in life). The probability that there'll be a fire AND the safety will fail is small enough for me. Likewise the probability that my cylinder will leak fast enough to fill up my drafty basement is small enough. It's a small cylinder. Bob |
co2 - safe handling?
On Aug 17, 5:03 pm, "Karl Townsend"
wrote: .... Did you get one for paintball filling or for welding? I don't plan to do any paintball. It's more for combat robotics. But I would assume that. from a procedure point of view, this would be like paintball. The tank I have is for paintball and has a siphon. the paintball unit has a tube inside the tank so liquid comes out when its upright, can't be used to weld. A weld tank has to be upside down to dispense liquid. Does securing the tank upside down make any sense? a small tube and valve kit is sold to hook the paintball tank up to the big tank. Comes with directions. basically you vent a little gas out of the paintball can and the pressure difference forces liquid across. Biggest issue with filling is freezing a line up - go slow. I've got a small tube like that. Made by Pure Energy. Didn't get any instructions. But it wasn't too hard to figure out. I was able to use it to "fill" a 9 oz tank but don't have a scale to check the wieght. DON'T OVERFILL. You need 20% headspace. Use a scale. "The kid" filled paintball tanks for all his friends when he was home. He overfilled one and, not knowing of a problem, put it in the car and started driving. It popped the relief valve with a bang while they were driving. They almost had an accident trying to jump out of the car cause they thought a bomb had went off. When you say don't overfill I assume you mean that there shouldn't be too much liquid in a tank? Thanks, DOC |
co2 - safe handling?
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co2 - safe handling?
On Aug 17, 7:02 pm, "Shaun Van Poecke"
wrote: .... an unusual way, splitting right down the side. It blew through the relatively thin wall and landed about 30 feet away on the road. I was outside the van trying to get in when it exploded. the safety release valve did not operate, there is a current investigation being made by BOC as to why. This sounds to me like there was a problem with the overpressure burst disk. Should have gone before the tank. Maybe the heat caused it to not preform as it should have. .... We did have a near miss last year while welding inside a copper smelting pot. These pots are used by the mine and hold about 90 tonnes of copper. You climb up a ladder to get inside, its like sitting in a giant coffee cup. Ah... I should be OK here. I don't drink that much coffee! :-)oo We weld tham back up with a dual shield filler with CO2 as the gas. The two staff welding the pot had gone for lunch and had turned off the extraction system for some peace and quiet. What had happened was the valve on the welding unit which controls the gas flow had stuck 'on'. gas was continuously pouring out the end of the nozzle at 20 litres a minute. Actually this story does bring up a good point. I usually keep the tank in an area that is relatively closed in. So if the tank were to start leaking, the co2 might be able to build up in the area. Appreciate the comments. DOC |
co2 - safe handling?
And if you happen to have confined spaces, particularly a cellar or similar, there is a real asphyxiation risk from a leak. ... I don't think so - breathing just a little would be so distressing that you'd immediately get-the-hell-out. It's the rise in CO2 concentration in our lungs that makes it so hard to hold your breath for very long. There's still plenty of oxygen in your lungs but the rising CO2 says: BREATH! BREATH!! You start experiencing that in your cellar and you'll be out of there long before asphyxiation is a risk. Bob In the UK I believe there's about one fatality a year, often people cleaning fermenting vessels in breweries. That said, I did some measurements and "calcs" for my local small brewery (Uley) which is in Victorian premises and managed to convince the Health & Safety inspector that the natural ventilation meant there was no risk in the cellar and that they therefore didn't need multiple linked detectors. |
co2 - safe handling?
On Fri, 17 Aug 2007 23:02:04 +0000, Shaun Van Poecke wrote:
Ive never actually breathed Co2 myself, though i have done my share of confined spaces welding. Im very concerned about following the right procedures for this type of work. I'd think if it was that concentrated, your mucus membranes would let you know RIGHT NOW, from the tingling, burning sensation as it dissolves in the moisture and turns to carbonic acid. I've accidentally sniffed "concentrated" CO2, and it was pretty obvious, and not pleasant at all. Thanks, Rich |
co2 - safe handling?
On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt wrote:
Shaun Van Poecke wrote: ... The cyllinder ruptured in an unusual way, splitting right down the side. ... the safety release valve did not operate, ... ... the Co2 filled up the copper pot ... the welder climbed into the pot ... once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. ... Shaun - thanks for the real-world input. Too many of our posts are speculation, sometimes not based on much knowledge. While accepting that CO2 is more dangerous than I believed, I'm still going to store my cylinder in the cellar. It's a probability thing (like most things in life). The probability that there'll be a fire AND the safety will fail is small enough for me. Likewise the probability that my cylinder will leak fast enough to fill up my drafty basement is small enough. It's a small cylinder. I don't think drafts will help that much, since CO2 sinks in air. But, you'd get an early warning when your pilot lights went out. ;-) Cheers! Rich |
co2 - safe handling?
Bob Engelhardt wrote:
Shaun Van Poecke wrote: ... The cyllinder ruptured in an unusual way, splitting right down the side. ... the safety release valve did not operate, ... ... the Co2 filled up the copper pot ... the welder climbed into the pot ... once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. ... Shaun - thanks for the real-world input. Too many of our posts are speculation, sometimes not based on much knowledge. While accepting that CO2 is more dangerous than I believed, I'm still going to store my cylinder in the cellar. It's a probability thing (like most things in life). The probability that there'll be a fire AND the safety will fail is small enough for me. Likewise the probability that my cylinder will leak fast enough to fill up my drafty basement is small enough. It's a small cylinder. Bob It's pretty easy to figure out how much breathable air a leaking cylinder could displace at atmospheric pressure, since that's typically the cylinder spec for most gasses (CO2 an exception). An 80cf Argon cylinder for TIG could at most displace 80cf of breathable air, or less than a foot off the floor even in a small ~10'x10' shop. Basically, a single home sized cylinder of inert gas completely emptying in a typical home size shop couldn't pose a threat to a human, though it could be a problem for your shop cat. In a house fire it is very likely that you would be out of the house long before a cylinder with a defective safety or no safety got hot enough to potentially fail catastrophically. Basically under normal home shop conditions you only have to worry about flammable gasses and oxygen, anything inert just can't realistically pose a safety hazard. Pete C. |
co2 - safe handling?
Dave Hinz wrote:
On Sat, 18 Aug 2007 11:07:43 -0700, wrote: On Aug 17, 4:38 pm, "Pete C." wrote: ... SCUBA tanks are a lot higher pressure than CO2. The only real issue with CO2 is the potential for frostbite if you manage to release it in liquid form on yourself. Just download the MSDS from the Airgas site. I recall the air tanks were around 3000 PSI and gather that co2 is somewhere around the 600 mark. Our SCBA tanks are pressurized up to 2215PSI. I have no idea where that number comes from. There are also 6000PSI tanks I seem to recall but...in a fire, one 2215PSI tank is all I can go through without being tired, not sure how much longer the 6000PSI would last but, longer than me. Aluminum SCUBA tanks are usually 3,000PSI, some are 3,300PSI. Steel SCUBA tanks are usually 2215PSI, though there are some HP versions. I've seen composite SCUBA tanks that run at 4,500PSI and that is also a common pressure for fire fighting SCBA tanks. The 2215PSI SCBA tanks are typically older ones from what I've seen and seen to be going away. I've not seen any portable SCUBA or SCBA tanks running at 6,000PSI, but cascade tank banks often operate that high so that they can fully fill the 3,000PSI tanks for a sizable draw down before the compressor needs to operate again. Pete C. |
co2 - safe handling?
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co2 - safe handling?
Pete C. wrote:
wrote: Just got myself a co2 tank designed to fill small paintball tanks. I plan to use this mostly for combat robotics and possibly for a MIG set up when I get MIG. I do have SCUBA experience, an air compressor and a TIG set up. But co2 seems to be a bit of a different horse as it is stored in liquid form. Looking for information sources on handling this safely. Favorite books, web sites, free advice... Tanks :-) for any help. DOC SCUBA tanks are a lot higher pressure than CO2. The only real issue with CO2 is the potential for frostbite if you manage to release it in liquid form on yourself. Just download the MSDS from the Airgas site. The bulk tank itself should require no more care than your other high pressure bottles. I understand that care is required in filling the small paintball tanks to insure there's always an adequate gas headspace above the liquid. If not, heat can cause the liquid to expand and explode the tank. |
co2 - safe handling?
Does securing the tank upside down make any sense?
You don't need to, you got the one for filling tanks. But you can't weld with this tank. When you say don't overfill I assume you mean that there shouldn't be too much liquid in a tank? Correct. If you put too much in you're going to pop something when everything warms back up from the filling process. Buy a scale, eBay is your friend here. Karl |
co2 - safe handling?
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co2 - safe handling?
On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt
wrote: Shaun Van Poecke wrote: ... The cyllinder ruptured in an unusual way, splitting right down the side. ... the safety release valve did not operate, ... ... the Co2 filled up the copper pot ... the welder climbed into the pot ... once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. ... Shaun - thanks for the real-world input. Too many of our posts are speculation, sometimes not based on much knowledge. While accepting that CO2 is more dangerous than I believed, I'm still going to store my cylinder in the cellar. It's a probability thing (like most things in life). The probability that there'll be a fire AND the safety will fail is small enough for me. Likewise the probability that my cylinder will leak fast enough to fill up my drafty basement is small enough. It's a small cylinder. Bob Wouldn't worry about it for the normal 5-pound or 10-pound CO2 cylinder you'd have for home shop use - you can't flood a room that well unless it's a full-size 50-pound tall bottle with several hundred CF of gas inside and a really small basement. Oh, and it may not be a pop-type resetting relief valve, they use a rupture disc relief on some cylinders, once it pops it fully vents. Ask the supplier what you have on any particular bottle. As that fire proved, even if the cylinder relief valve vents, it may not vent fast enough to prevent cylinder rupture in a fire. But I'll bet there was a time delay between venting and popping, and everyone had a chance to get out of the way. -- Bruce -- |
co2 - safe handling?
Bob Engelhardt writes:
It's the rise in CO2 concentration in our lungs that makes it so hard to hold your breath for very long. There's still plenty of oxygen in your lungs but the rising CO2 says: BREATH! BREATH!! CO2 is not just an inert oxygen-displacing gas like other shielding gases or fuels. Respiration takes O2 in and sends CO2 out. Too little pO2 or too much pCO2 in the ambient will kill you, either one. Yes, CO2 is a sensible respiratory stimulant in low concentrations, and not toxic in the sense that it is something your body produces and a strong whiff will not hurt you. But even with enough pO2 it doesn't take much pCO2 in the ambient air to prevent you from clearing CO2 from the blood and getting very distressed, even if the rest is pure O2. |
co2 - safe handling?
Rich Grise wrote:
On Sat, 18 Aug 2007 14:12:03 -0400, Bob Engelhardt wrote: Shaun Van Poecke wrote: ... The cyllinder ruptured in an unusual way, splitting right down the side. ... the safety release valve did not operate, ... ... the Co2 filled up the copper pot ... the welder climbed into the pot ... once he was inside the pot he was overcome pretty quickly by dizziness and was unable to get out. ... Shaun - thanks for the real-world input. Too many of our posts are speculation, sometimes not based on much knowledge. While accepting that CO2 is more dangerous than I believed, I'm still going to store my cylinder in the cellar. It's a probability thing (like most things in life). The probability that there'll be a fire AND the safety will fail is small enough for me. Likewise the probability that my cylinder will leak fast enough to fill up my drafty basement is small enough. It's a small cylinder. I don't think drafts will help that much, since CO2 sinks in air. But, you'd get an early warning when your pilot lights went out. ;-) Or when the furnace comes on and starts pumping out CO.. John Cheers! Rich |
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