On Thu, 30 Oct 2008 17:33:17 -0800, bart wrote:

Hi all,

I hope I'm not too way off base here in asking for advice, but you guys
seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to "make
it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTAL-
CHAMBER-0_W0QQitemZ320301576211QQcmdZViewItem?_trksid=p328 6.m20.l1116)

When we recieved it, it didn't "do" anything. I kept flipping the
switch back & forth and eventually some sticky relays started
"working", that is, the heater /fan started working and the gas solenoid
clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2. Somebody
retrofitted it with a 300PSI solenoid - We have since then gotten a
1000PSI liquid CO2 solenoid. The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by next
week.
Now I have a basic oxy/acetylene rig at home, but have never played with
liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper, stainless,
double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)

I'm gonna say a bunch of stuff, some of which I'm not 100% sure of. So
before you do anything actionable you should check on everything I say.

In the sense that too much of it will cause biochemical changes in your
body that will kill you, he's wrong. CO2 _is_ toxic. It's a lot _less_
toxic than a lot of other things, but your breathing is regulated by the
level of CO2 in your blood. If I recall correctly too much CO2 will tend
to make you hyperventilate at first, then it will overwhelm the
regulatory system and you'll stop breathing. This is why deep-sea diving
systems that use rebreathers have CO2-absorbing packs (with what, lime?)
in spite of the hazards they pose (caustic fluid if you get water in it,
I think). Just adding oxygen to your breath and re-breathing it will
kill you, so I'm sure that dumping a bunch of CO2 in a room can't be good.

Too little CO2 and you'll just stop breathing. Your body thinks you're
better than fine, and the pump stops*. This is why medical oxygen has
some CO2 mixed in.

I honestly don't know if this thing is going to vent enough CO2 in there
to be fatal. I'm pretty sure it won't be good, though. At the very
least it'll make everyone in range uncomfortable without them necessarily
knowing why (it'll feel very stuffy in there).

Even chambers that use LN2 have to be vented, or at least be installed in
ventilated rooms, and the rooms they're in are (I believe) supposed to
have oxygen monitors present and operating. And this is all for a gas
that simply isn't toxic at normal atmospheric pressures -- N2 + CO2 + O2
will keep you alive forever, but enough N2 will displace the oxygen in
the air and you'll keel over without ever being aware of a problem.

So I would think that your boss is demanding that you make your working
environment unsafe, then he's demanding that you work in it. Not only do
I not think it's wise to do as he says, I'm not even sure that it would
be ethical to quit and keep your mouth shut about it (more on that later).

Depending on how reasonable he is I would suggest that you do some web
searching on the toxicity of CO2 and show him your results. It may make
him think, and at least you will have tried.

If you don't think that's wise, then much as I hate to say this** you
should consider turning him in to your local OSHA. They're a bunch of
pricks, but if LN2-cooled enviro chambers merit the level of care than I
see them being treated with, a CO2-cooled enviro chamber can only be
worse. In most states your boss won't be able to fire you for turning
him in, but if he's an a**hole he can make you miserable in a million and
one different ways. (such fights are never good -- it seems like the
only people that come out unscathed by such experiences are a**holes to
the point of being diseased).

The problem with quietly getting another job is that you _know_ he's
gonna tell your replacement to do exactly the same thing -- do you want
to read about the death(s) in your local paper?

Oregon _used_ to have a portion of their "OSHA" dedicated to helping
employers set up a safe work place -- basically it was state-funded
industrial hygienists who did _not_ report back to the enforcers, who
would advise business on how to comply with the law. Your local
government may have something like that, although I would have no clue of
how you or your boss could go about finding them.

* This is yet another example of how the human body is very poorly
designed, if designed it is. A good designer would have taken high CO2
concentrations into account and made a better breathing controller. If
we're designed then God was paying a bit too much attention to the
production schedule instead of doing the engineering right.

** I find this very hard to write, because my father's company got
absolutely reamed by a couple of disgruntled employees who turned him in
to the state Accident Prevention Division. When that didn't damage him
enough for their vindictive little hearts, they started sabotaging
tooling and fixtures. When he fired them, they sued on the grounds that
they had turned him in to APD. He won, but it was expensive, it lasted
for almost two years, and it did _really bad_ things to employee moral
(not to mention giving me some very ambivalent feelings toward government
regulators).

On the other hand, there's enough a**hole bosses around that you can't
ignore them; OSHA cops are like any others -- you don't want them around
unless you're in trouble, then you want them right there, immediately and
in force.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!
B

bart wrote:
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work". ( this one's sibling:

When we recieved it, it didn't "do" anything. I kept flipping the
switch back & forth and eventually some sticky relays started
"working", that is, the heater /fan started working and the gas
solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2. Somebody
retrofitted it with a 300PSI solenoid - We have since then gotten a
1000PSI liquid CO2 solenoid. The wiring in it is OLD and BRITTLE,
BTW.

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


A few hours ago my boss is on my ass to get the cooling working by
next week. Now I have a basic oxy/acetylene rig at home, but have
never played with liquid CO2.

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.


I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't
going to vent it. (it's setup in the back of a kitchen, where I work
{our "lab"}- with zero ventilation)

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.

http://www.uigi.com/carbondioxide.html

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


I don't mind doing potentially dangerous stuff in my own garage (
with the door open), but this is an office full of people.

VERY STUPID IDEA.


Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without
ventilation?)

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



Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance! B


--
Steve W.
Near Cooperstown, New York


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Tim Wescott wrote:

On Thu, 30 Oct 2008 17:33:17 -0800, bart wrote:

Hi all,

I hope I'm not too way off base here in asking for advice, but you guys
seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to "make
it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTAL-
CHAMBER-0_W0QQitemZ320301576211QQcmdZViewItem?_trksid=p328 6.m20.l1116)

When we recieved it, it didn't "do" anything. I kept flipping the
switch back & forth and eventually some sticky relays started
"working", that is, the heater /fan started working and the gas solenoid
clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2. Somebody
retrofitted it with a 300PSI solenoid - We have since then gotten a
1000PSI liquid CO2 solenoid. The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by next
week.
Now I have a basic oxy/acetylene rig at home, but have never played with
liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper, stainless,
double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)

I'm gonna say a bunch of stuff, some of which I'm not 100% sure of. So
before you do anything actionable you should check on everything I say.

In the sense that too much of it will cause biochemical changes in your
body that will kill you, he's wrong. CO2 _is_ toxic. It's a lot _less_
toxic than a lot of other things, but your breathing is regulated by the
level of CO2 in your blood. If I recall correctly too much CO2 will tend
to make you hyperventilate at first, then it will overwhelm the
regulatory system and you'll stop breathing. This is why deep-sea diving
systems that use rebreathers have CO2-absorbing packs (with what, lime?)
in spite of the hazards they pose (caustic fluid if you get water in it,
I think). Just adding oxygen to your breath and re-breathing it will
kill you, so I'm sure that dumping a bunch of CO2 in a room can't be good.

Too little CO2 and you'll just stop breathing. Your body thinks you're
better than fine, and the pump stops*. This is why medical oxygen has
some CO2 mixed in.

I honestly don't know if this thing is going to vent enough CO2 in there
to be fatal. I'm pretty sure it won't be good, though. At the very
least it'll make everyone in range uncomfortable without them necessarily
knowing why (it'll feel very stuffy in there).

Even chambers that use LN2 have to be vented, or at least be installed in
ventilated rooms, and the rooms they're in are (I believe) supposed to
have oxygen monitors present and operating. And this is all for a gas
that simply isn't toxic at normal atmospheric pressures -- N2 + CO2 + O2
will keep you alive forever, but enough N2 will displace the oxygen in
the air and you'll keel over without ever being aware of a problem.

So I would think that your boss is demanding that you make your working
environment unsafe, then he's demanding that you work in it. Not only do
I not think it's wise to do as he says, I'm not even sure that it would
be ethical to quit and keep your mouth shut about it (more on that later).

Depending on how reasonable he is I would suggest that you do some web
searching on the toxicity of CO2 and show him your results. It may make
him think, and at least you will have tried.

If you don't think that's wise, then much as I hate to say this** you
should consider turning him in to your local OSHA. They're a bunch of
pricks, but if LN2-cooled enviro chambers merit the level of care than I
see them being treated with, a CO2-cooled enviro chamber can only be
worse. In most states your boss won't be able to fire you for turning
him in, but if he's an a**hole he can make you miserable in a million and
one different ways. (such fights are never good -- it seems like the
only people that come out unscathed by such experiences are a**holes to
the point of being diseased).

The problem with quietly getting another job is that you _know_ he's
gonna tell your replacement to do exactly the same thing -- do you want
to read about the death(s) in your local paper?

Oregon _used_ to have a portion of their "OSHA" dedicated to helping
employers set up a safe work place -- basically it was state-funded
industrial hygienists who did _not_ report back to the enforcers, who
would advise business on how to comply with the law. Your local
government may have something like that, although I would have no clue of
how you or your boss could go about finding them.

* This is yet another example of how the human body is very poorly
designed, if designed it is. A good designer would have taken high CO2
concentrations into account and made a better breathing controller. If
we're designed then God was paying a bit too much attention to the
production schedule instead of doing the engineering right.

** I find this very hard to write, because my father's company got
absolutely reamed by a couple of disgruntled employees who turned him in
to the state Accident Prevention Division. When that didn't damage him
enough for their vindictive little hearts, they started sabotaging
tooling and fixtures. When he fired them, they sued on the grounds that
they had turned him in to APD. He won, but it was expensive, it lasted
for almost two years, and it did _really bad_ things to employee moral
(not to mention giving me some very ambivalent feelings toward government
regulators).

On the other hand, there's enough a**hole bosses around that you can't
ignore them; OSHA cops are like any others -- you don't want them around
unless you're in trouble, then you want them right there, immediately and
in force.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

If you find an instruction and safety manual for the chamber or a
similar one and read that I expect you'll be fine.

In article ,
bart wrote:

Just wanted another opinion.

(And yes, I am looking for another job)

Look harder

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/
** Posted from http://www.teranews.com **

"bart" wrote in message
...
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!
B

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

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

Grumpy wrote:

"bart" wrote in message
...
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!
B

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.

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


Vent the room or you may kill someone

And liquid CO2 will not cool anything, unless you make it cold, which
I presume you plan to do by venting some of it into your "controlled
space".

"Pete C." wrote:


Tim Wescott wrote:

On Thu, 30 Oct 2008 17:33:17 -0800, bart wrote:

Hi all,

I hope I'm not too way off base here in asking for advice, but you guys
seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to "make
it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTAL-
CHAMBER-0_W0QQitemZ320301576211QQcmdZViewItem?_trksid=p328 6.m20.l1116)

When we recieved it, it didn't "do" anything. I kept flipping the
switch back & forth and eventually some sticky relays started
"working", that is, the heater /fan started working and the gas solenoid
clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2. Somebody
retrofitted it with a 300PSI solenoid - We have since then gotten a
1000PSI liquid CO2 solenoid. The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by next
week.
Now I have a basic oxy/acetylene rig at home, but have never played with
liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper, stainless,
double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)

I'm gonna say a bunch of stuff, some of which I'm not 100% sure of. So
before you do anything actionable you should check on everything I say.

In the sense that too much of it will cause biochemical changes in your
body that will kill you, he's wrong. CO2 _is_ toxic. It's a lot _less_
toxic than a lot of other things, but your breathing is regulated by the
level of CO2 in your blood. If I recall correctly too much CO2 will tend
to make you hyperventilate at first, then it will overwhelm the
regulatory system and you'll stop breathing. This is why deep-sea diving
systems that use rebreathers have CO2-absorbing packs (with what, lime?)
in spite of the hazards they pose (caustic fluid if you get water in it,
I think). Just adding oxygen to your breath and re-breathing it will
kill you, so I'm sure that dumping a bunch of CO2 in a room can't be good.

Too little CO2 and you'll just stop breathing. Your body thinks you're
better than fine, and the pump stops*. This is why medical oxygen has
some CO2 mixed in.

I honestly don't know if this thing is going to vent enough CO2 in there
to be fatal. I'm pretty sure it won't be good, though. At the very
least it'll make everyone in range uncomfortable without them necessarily
knowing why (it'll feel very stuffy in there).

Even chambers that use LN2 have to be vented, or at least be installed in
ventilated rooms, and the rooms they're in are (I believe) supposed to
have oxygen monitors present and operating. And this is all for a gas
that simply isn't toxic at normal atmospheric pressures -- N2 + CO2 + O2
will keep you alive forever, but enough N2 will displace the oxygen in
the air and you'll keel over without ever being aware of a problem.

So I would think that your boss is demanding that you make your working
environment unsafe, then he's demanding that you work in it. Not only do
I not think it's wise to do as he says, I'm not even sure that it would
be ethical to quit and keep your mouth shut about it (more on that later).

Depending on how reasonable he is I would suggest that you do some web
searching on the toxicity of CO2 and show him your results. It may make
him think, and at least you will have tried.

If you don't think that's wise, then much as I hate to say this** you
should consider turning him in to your local OSHA. They're a bunch of
pricks, but if LN2-cooled enviro chambers merit the level of care than I
see them being treated with, a CO2-cooled enviro chamber can only be
worse. In most states your boss won't be able to fire you for turning
him in, but if he's an a**hole he can make you miserable in a million and
one different ways. (such fights are never good -- it seems like the
only people that come out unscathed by such experiences are a**holes to
the point of being diseased).

The problem with quietly getting another job is that you _know_ he's
gonna tell your replacement to do exactly the same thing -- do you want
to read about the death(s) in your local paper?

Oregon _used_ to have a portion of their "OSHA" dedicated to helping
employers set up a safe work place -- basically it was state-funded
industrial hygienists who did _not_ report back to the enforcers, who
would advise business on how to comply with the law. Your local
government may have something like that, although I would have no clue of
how you or your boss could go about finding them.

* This is yet another example of how the human body is very poorly
designed, if designed it is. A good designer would have taken high CO2
concentrations into account and made a better breathing controller. If
we're designed then God was paying a bit too much attention to the
production schedule instead of doing the engineering right.

** I find this very hard to write, because my father's company got
absolutely reamed by a couple of disgruntled employees who turned him in
to the state Accident Prevention Division. When that didn't damage him
enough for their vindictive little hearts, they started sabotaging
tooling and fixtures. When he fired them, they sued on the grounds that
they had turned him in to APD. He won, but it was expensive, it lasted
for almost two years, and it did _really bad_ things to employee moral
(not to mention giving me some very ambivalent feelings toward government
regulators).

On the other hand, there's enough a**hole bosses around that you can't
ignore them; OSHA cops are like any others -- you don't want them around
unless you're in trouble, then you want them right there, immediately and
in force.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

If you find an instruction and safety manual for the chamber or a
similar one and read that I expect you'll be fine.

jk

On Thu, 30 Oct 2008 17:33:17 -0800, bart wrote:

Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!

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.

On Fri, 31 Oct 2008 14:53:19 +1100, "Grumpy"
wrote:

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

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.

-- Bruce --

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


Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

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

http://www.kewego.com/video/iLyROoaftIDS.html

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

Larry Jaques wrote:

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


Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

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

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:

Larry Jaques wrote:

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

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

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

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

Larry Jaques wrote:

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

Larry Jaques wrote:

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

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

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

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

bart wrote:
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

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.
Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

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 mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)
I don't know about your regulatory environment, if there are OSHA
inspectors popping in every week, you'd better go legal.

Jon

jk wrote:
And liquid CO2 will not cool anything, unless you make it cold, which
I presume you plan to do by venting some of it into your "controlled
space".
No, it goes through coils brazed to the sides of the chamber. There's
an orifice at the solenoid valve, then the liquid expands in the coils
at low pressure, absorbing lots of heat.

Jon

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

They may use two bottles and a proportional mixing valve.

Joe Gwinn

On Thu, 30 Oct 2008 23:43:59 -0500, Don Foreman
wrote:

On Thu, 30 Oct 2008 17:33:17 -0800, bart wrote:


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.


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

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

They may use two bottles and a proportional mixing valve.

Joe Gwinn

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.

"Pete C." wrote in message
ster.com...

Grumpy wrote:

"bart" wrote in message
...
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!
B

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.

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


Vent the room or you may kill someone


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.

On Fri, 31 Oct 2008 22:55:58 +0000, Mark Rand
wrote:


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

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:

On Fri, 31 Oct 2008 22:55:58 +0000, Mark Rand
wrote:


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

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

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

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

On Sat, 01 Nov 2008 01:00:59 -0500, Don Foreman
wrote:

On Fri, 31 Oct 2008 22:55:58 +0000, Mark Rand
wrote:


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

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

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


I typed Draeger as in Dräger Tube but it came out as Deager.

Bloody keyboard can't spell :-|


Mark Rand
RTFM

On Oct 30, 6:33*pm, bart wrote:
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)

Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:http://cgi.ebay.com/AES-ENVIRONMENTA...mZ320301576211...)

When we recieved *it, it didn't "do" anything.
I kept flipping the switch back & forth *and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)

Just wanted another opinion.

(And yes, I am looking for another job)

Thanks in Advance!
B

you must vent he co2 out side. It is heavier than air and in
concetrations of 2% will kill you. Call liquid air-linde compant they
do a lot of this. You can get cylinders with both a liguid and a gas
tap.

Grumpy wrote:

"Pete C." wrote in message
ster.com...

Grumpy wrote:

"bart" wrote in message
...
Hi all,

I hope I'm not too way off base here in asking for advice, but you
guys seem to know everything!! :-)


Boss at work bought a $99.00 environmental chamber and told me to
"make it work".
( this one's sibling:
http://cgi.ebay.com/AES-ENVIRONMENTA...8 6.m20.l1116)

When we recieved it, it didn't "do" anything.
I kept flipping the switch back & forth and eventually some sticky
relays started "working", that is, the heater /fan started working and
the gas solenoid clicked in - depending on the temperature dial.

A label on the back says it is to be cooled with liquid CO2.
Somebody retrofitted it with a 300PSI solenoid - We have since then
gotten a 1000PSI liquid CO2 solenoid.
The wiring in it is OLD and BRITTLE, BTW.

A few hours ago my boss is on my ass to get the cooling working by
next week.
Now I have a basic oxy/acetylene rig at home, but have never played
with liquid CO2.

I'm not exactly sure of what fittings/tubing to use ( copper,
stainless, double flare??).

Also, the boss says that CO2 isn't toxic, so therefore we aren't going
to vent it.
(it's setup in the back of a kitchen, where I work {our "lab"}- with
zero ventilation)

I don't mind doing potentially dangerous stuff in my own garage ( with
the door open), but this is an office full of people.

Am I way off base telling him to hire a professional to do the gas
fitting ( and leave the premises when he runs it without ventilation?)


Just wanted another opinion.

(And yes, I am looking for another job)



Thanks in Advance!
B

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.

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


Vent the room or you may kill someone

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.

Dry ice is -109.something I believe.

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled
chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it
tends
to be a greater risk to children and animals, which probably aren't
an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a
couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

They may use two bottles and a proportional mixing valve.

Joe Gwinn

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.

I do recall reading such articles, but a trip to Google revealed only
hints, perhaps a residue of pre-internet medical approaches. The
standard of care for carbon monoxide poisoning is now the hyperbaric
chamber, at 3 atmospheres. Hyperbaric chambers were uncommon 20 years
ago, so it does fit together.

Joe Gwinn

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

Joseph Gwinn wrote:

In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled
chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it
tends
to be a greater risk to children and animals, which probably aren't
an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a
couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

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.

They may use two bottles and a proportional mixing valve.

Joe Gwinn

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.

I do recall reading such articles, but a trip to Google revealed only
hints, perhaps a residue of pre-internet medical approaches. The
standard of care for carbon monoxide poisoning is now the hyperbaric
chamber, at 3 atmospheres. Hyperbaric chambers were uncommon 20 years
ago, so it does fit together.

Joe Gwinn

CO2 in the O2 probably dates back to the days of iron lungs...