Enviro chamber liquid CO2 question?

So the wiring is already a fire hazard! And if the wiring is old and brittle I would bet the seals are the same.

NOT a good thing. If you don't know how to work with it tell him to get someone else to set the damn thing up.

VERY, VERY wrong. CO2 IS toxic. It will KILL YOU easily enough if it builds up. Your boss is an IDIOT.

How can carbon dioxide affect my health?

Carbon dioxide in its gas form is an asphyxiant, which cuts off the oxygen supply for breathing, especially in confined spaces. Exposure to concentrations of 10 percent or more of carbon dioxide can cause death, unconsciousness, or convulsions. Exposure may damage a developing fetus.

Exposure to lower concentrations of carbon dioxide can cause hyperventilation, vision damage, lung congestion, central nervous system injury, abrupt muscle contractions, elevated blood pressure, and shortness of breath. Exposure can also cause dizziness, headache, sweating, fatigue, numbness and tingling of extremities, memory loss, nausea, vomiting, depression, confusion, skin and eye burns, and ringing in the ears.

You may be more affected by exposure to carbon dioxide if you have a cardiac, lung, or blood disease or condition.

CO2 is an acidic oxide: an aqueous solution turns litmus from blue to pink. CO2 is toxic in higher concentrations: 1% (10,000 ppm) will make some people feel drowsy. Concentrations of 7% to 10% cause dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour.

ANY environmental chamber should have venting if it uses any compressed gas other than room air.

VERY STUPID IDEA.

Turn him in to OSHA. If he is willing to kill his employees to save a buck he deserves jail time.

Look harder ;)

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

** Posted from **

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CO2 can be dangerous.

I spent a lot of time as an engineer in the brewing industry,and we worked with it all the time. The 1000psi solenoid is pretty low as co2 can reach

1200 psi on a hot day. We used conventional steel pipe and flaged fittings, but as you are only using small sizes flared stainless steel would probably be appropriate.

Vent the room or you may kill someone

[snip]

There is one exception - treating cases of carbon monoxide poisoning. If I recall, the mix is 5% CO2 and 95% O2. The CO2 displaces the CO, and the almost pure oxygen keeps you alive while this happens. Reportedly it is very stressful to breathe this stuff - you feel that you cannot get enough air, and yet are perfectly OK.

Joe Gwinn

Well, there is clearly more than one exception since my med O2 cylinders contain *gasp* 100% O2. Also all my medical literature related to emergency O2 use refer to 100% O2.

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I would suggest SS tubing and the Swage-lock fittings to avoid the tooling hassle of flared fittings.

Ordinary copper tubing isn't rated for that kind of pressure. Use steel or stainless. A visit to a good welding store should get you some knowledgable advice and the materials you'll need.

All occupied spaces must be ventilated to some extent or the occupants would eventually suffocate. HVAC systems handle this for normal occupancy.

Fresh air has a natural CO2 content of about 385 ppm. Due to the health risks associated with carbon dioxide exposure, the U.S. Occupational Safety and Health Administration says that average exposure for healthy adults during an eight-hour work day should not exceed 5,000 ppm (0.5%).

0.5% - 385ppm = 0.462%. An amount of CO2 necessary to approach this concentration could be released in a space once per air change. I think OSHA regs call for a minimum of 4 air changes per hour but there are various conditions that require more. Ask an HVAC expert about that or do a bit of web research on the subject.

If you release 125 cubic feet of CO2 in 15 minutes (about one 5' tall cylinder, 4 air changes per hour), the room/space would need to contain about 27,000 cu ft of air to achieve the necessary dilution. With 10 ft ceilings that would be an area of 2700 sq ft.

Scale accordingly for use of less CO2. I strongly doubt that your box will use CO2 at anywhere near this rate of 500 cu ft/hr. That'd be about 61 lb of liquid or dry ice.

I recall using boxes like this 40 years ago. Some used liquid CO2, others dry ice. They weren't very big; a few cubic feet of capacity inside. They worked surprisingly well, holding set temp to within a couple of degrees. No special ventilation measures were used. A 10 lb block of dry ice lasted most of an 8 hour shift.

1200 PSI at hot room temperatures in a steel cylinder yes, but not in a Cryo Dewar style bottle - for those the 300 PSI solenoid would be plenty. And if you are getting it in bulk they will deliver in a big truck-mount tank and pump it into your dewar.

Plus, most steel cylinders do not have a siphon inside for delivering liquid CO2 for use. For an enviro chamber you will be using the "Liquid" tap on the dewar, and counting on internal pressure to deliver the product - might even have to pressurize the dewar with shop air or Nitrogen to keep the flow constant. Or have an electric heater inside to keep the pressure up.

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On Thu, 30 Oct 2008 23:18:46 -0500, the infamous "Pete C." scrawled the following:

Hey, Pete, have you old farts with the oxy carts seen this video?

Oops, I thought I remembered her with O2. Sorry.

(metal content, somewhere)

-- Everything I did in my life that was worthwhile I caught hell for. -- Earl Warren

I'm not an old fart with an oxy cart, I'm a diver with an O2 emergency kit and an oxygen analyzer.

On Fri, 31 Oct 2008 08:53:01 -0500, the infamous "Pete C." scrawled the following:

Aww, you're no fun at all, Pete.

-- Everything I did in my life that was worthwhile I caught hell for. -- Earl Warren

Sadly, I've never been accused of being fun, well except when I'm making LN2 ice cream...

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I think any 1/4" metal tubing should handle it fine. it is about 900 PSI in the bottle. Do you use this without a regulator? I guess so. Any, you want a siphon-tube bottle for the CO2.

It is a small chamber, unless the room is SEALED, I wouldn't worry about it. If you DO worry, just get a window fan and set it in the open door while it is running, should be plenty of ventilation.

I don't know about your regulatory environment, if there are OSHA inspectors popping in every week, you'd better go legal.

Jon

They may use two bottles and a proportional mixing valve.

Joe Gwinn

Further to your comments, 40 years ago the rooms may have been far more "leaky" than they tend to be nowadays.

5% CO2 will cause unconsciousness in some individuals and 10% will eventually cause unconsciousness and death in all individuals.

I speak as one who lost consciousness due to an environment that was later measured with a Dreager tester to have 5% CO2. Since that environment happened to be a very well sealed full-face crash helmet in a rain storm, I was extremely lucky to get away with only a broken leg and a written off motorcycle...

Mark Rand RTFM

No, they do not. The two bottles are both 100% O2, the regulator connects to one cylinder and directly feeds the mask(s), supporting one adjustable continuous flow mask and/or up to two demand valve masks. The two cylinders are strictly for run time.

I've not read any medical literature referring to administration of less than 100% O2. Indeed the only place I'm aware of where breathing gas mixes regularly contain more than 21% O2 and less than 100% O2 is diving where it's called Nitrox or Enriched Air Nitrox (EANx). No breathing gas mix I have ever seen deliberately contains any CO2, the mixes that do contain it only contain it due to containing some percentage of ambient air.

>> >

Yes you're right. We also used those to good effect and they were easier to use. As some of our lines were 2" those were always welded and flanged. We kept the liquid at about minus 30 Deg Fahrenheit so the pressure ran about 300 PSI if I remember correctly. It was handy to have a few tons of liquid CO2 around if you wanted a shrink fit on anything. We'd expand it through a rag stuffed into a reducing bush. Instant dry ice. It would cool things down to about minus 50.

I'll bet you meant Draeger, as in Draeger rebreather, rather than Dreager.

Luck counts, both ways. Glad you had good luck that day.

On Sat, 01 Nov 2008 01:00:59 -0500, the infamous Don Foreman scrawled the following:

I'm reading _First Seal_ by Roy Boehm right now and he just cursed his supply officer for putting Scott rebreathers (open circuit, bubbles to the surface) on the sub which was taking them to Cuba to scout around. Upon release from the sub at 60', one of his men urgently swam to the surface with brine in the damned thing. He got lucky with inferior product that day, too. Boehm had specified Draeger closed circuit) rebreathers for safety and stealth, and had actually tossed the idiot officer (a Naval engineer, no less) into the pool once, knowing that the guy couldn't swim. The guy didn't learn his lesson, so I'm waiting to read (later this morning) how Roy got back at him for that second sleight. I'll bet it's a doozy.

Anywho, I find it fun when the group topic parallels my current book. (Yes, I'm easily amused.)

-- Everything I did in my life that was worthwhile I caught hell for. -- Earl Warren