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