Medal Winners: Air Traffic Control Tapes

On Fri, 3 Feb 2006 23:31:17 -0600, "JJS" jschneider@remove socks
cebridge.net wrote:


"Drew Dalgleish" wrote in message ...
On Fri, 03 Feb 2006 06:05:45 GMT, Richard Lamb
wrote:

Morgans wrote:


"Roger" wrote

Then he committed a sin for which job termination is usually
proscribed at most companies now days. You never, ever enter a vessel
that has been N2 purged unless bringing your own breathing air by
tank or hose. He entered without checking the O2 level and almost
suffocated.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The first post about this said:

The catalyst vessel he was working in was under
nitrogen atmosphere to prevent the catalyst from going pyrophoric.
There was no pressure on the vessel and the
manway was open. He removed is mask to spit, then inhaled before
putting it back on. Instead of passing out, he
instantly went into violent convulsions and dropped the mask. Even with
an attendant equipped with a radio, and a
tripod, winch, and lanyard already set up and attached we only got him
out of the vessel alive by the grace of God.

There HAD to be something else in the atmosphere, Jim.

N2 just doesn't do that (does it???)

Richard

N2 doesn't do anything except displace O2 Lack of O2 normally causes
the victim to just pass out almost instantly followed by convulsions
then the cessation of respiration. ( quoted directly from the ontario
mine rescue handbook)

Drew, Can you point me to a link. A very quick google search didn't turn up much from Ontario. I'd like to verify
the "lack of O2 normally causes the victim to pass out almost instantly". Ever see someone in a choke lose
consciousness instantly or go into convulsions after they pass out. I've seen them go unconscious but it took
minutes not seconds and I've never witnessed follow up convulsions.

Joe Schneider
8437R

Joe The ontario mine rescue website is www.masha.on.ca but I
couldn't find an on line copy of our training manuel so I'll type out
the appropriate couple paragraphs per vatim

When there is no oxygen in the atmosphere, loss of consciosness is
quicker than in drowning. Not only is the supply of oxygen cut off,
but the oxygen in the lungs is rapidly depleted. Loss of conscionsness
is followed by convulsions, then cessation of respiration.
The effects of extreme oxygen deficiency are so rapid that ones life
is in peril before one relizes the danger.

The answer to the second question is no. I ocasionally do confined
space work but not normally in irrespirable atmospheres. For
firefighting we wear BG4 appatatus witch is a pure oxygen rebreather.

JJS jschneider@remove socks cebridge.net wrote:

"Drew Dalgleish" wrote in message ...
snip
N2 doesn't do anything except displace O2 Lack of O2 normally causes
the victim to just pass out almost instantly followed by convulsions
then the cessation of respiration. ( quoted directly from the ontario
mine rescue handbook)

Drew, Can you point me to a link. A very quick google search didn't turn up much from Ontario. I'd like to verify
the "lack of O2 normally causes the victim to pass out almost instantly". Ever see someone in a choke lose
consciousness instantly or go into convulsions after they pass out. I've seen them go unconscious but it took
minutes not seconds and I've never witnessed follow up convulsions.

Totally different situations.

In one, you've got lungs full of stale air.
There is a reasonable amount of O2 in it, even after you pass out
(IIRC).

Hemeoglobin is very clever, but it's not magic.
It releases the molecule it's bound to (O2 or CO2) when it reaches somewhere
there isn't much of that gas.

Normally this is a good thing, but when the lungs are full of N2, not
only do you get the normal release of CO2, but the lungs now actively
strip oxygen from the blood, something which normally never happens.

And, any further breaths simply make this worse, as they get rid of any
oxygen that may have been in the lungs as a remenant, or stripped from
the blood flowing through them.

Much the same thing (though slightly more severe, with the additional
possible complication of burst lungs) happens when you breath vacuum.

"Ian Stirling" wrote in message ...
Totally different situations.

In one, you've got lungs full of stale air.
There is a reasonable amount of O2 in it, even after you pass out
(IIRC).

Hemeoglobin is very clever, but it's not magic.
It releases the molecule it's bound to (O2 or CO2) when it reaches somewhere
there isn't much of that gas.

Normally this is a good thing, but when the lungs are full of N2, not
only do you get the normal release of CO2, but the lungs now actively
strip oxygen from the blood, something which normally never happens.

And, any further breaths simply make this worse, as they get rid of any
oxygen that may have been in the lungs as a remenant, or stripped from
the blood flowing through them.

Much the same thing (though slightly more severe, with the additional
possible complication of burst lungs) happens when you breath vacuum.

Ding! The light bulb is flickering. Thanks Ian, for being patient enough with me and taking the time to educate. I
was aware that hemoglobin exchanges CO2 and O2. I wasn't aware that it did so in the manner you describe releasing
either in a low presence of the gas in question. That is very interesting. I still do not understand why it took
the victim so long to recover from a lack of oxygen unless there really was some brain damage that he recovered from
over time?? Do you have any links to the CO2/O2 exchange mechanism for further reading?

Joe Schneider
N8437R



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JJS wrote:
"Ian Stirling" wrote in message ...

Totally different situations.

In one, you've got lungs full of stale air.
There is a reasonable amount of O2 in it, even after you pass out
(IIRC).

Hemeoglobin is very clever, but it's not magic.
It releases the molecule it's bound to (O2 or CO2) when it reaches somewhere
there isn't much of that gas.

Normally this is a good thing, but when the lungs are full of N2, not
only do you get the normal release of CO2, but the lungs now actively
strip oxygen from the blood, something which normally never happens.

And, any further breaths simply make this worse, as they get rid of any
oxygen that may have been in the lungs as a remenant, or stripped from
the blood flowing through them.

Much the same thing (though slightly more severe, with the additional
possible complication of burst lungs) happens when you breath vacuum.


Ding! The light bulb is flickering. Thanks Ian, for being patient enough with me and taking the time to educate. I
was aware that hemoglobin exchanges CO2 and O2. I wasn't aware that it did so in the manner you describe releasing
either in a low presence of the gas in question. That is very interesting. I still do not understand why it took
the victim so long to recover from a lack of oxygen unless there really was some brain damage that he recovered from
over time?? Do you have any links to the CO2/O2 exchange mechanism for further reading?

Joe Schneider
N8437R


I have to offer my thanks too, Ian.

Pretty Scary Stuff.


Richard

On Fri, 3 Feb 2006 23:23:13 -0600, "JJS" jschneider@remove socks
cebridge.net wrote:


"Roger" wrote in message news
Then he committed a sin for which job termination is usually
proscribed at most companies now days. You never, ever enter a vessel
that has been N2 purged unless bringing your own breathing air by
tank or hose. He entered without checking the O2 level and almost
suffocated.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Roger, did you miss my post and just reply to the response that was snipped by Bryan Martin without him indicating he
did so?

Yup. Never saw it and I *tried" to cover the whole thread.

It was I who filled out and signed the safe work and confined space entry permits. One of my direct reports took the
gas samples with a handheld gas meter. The confined space entry was done correctly per OSHA 1910.146 confined space
procedures. At my place of employment we have to make confined space entries on a routine basis.

As did I, even though at the time I was an Instrument tech. They put
instruments in some strange places. :-))

An attendant was present. An Emergency Response Team was on standby. One thing though, there was no forced air
ventilation. He was using a supplied air respirator (air line mask) with a backup egress system. This was a
professional contract company that does IDLH confined space entries for catalyst work as their sole source of income.
Forced air ventilation will not make a "confined space" a "non-confined space" per OSHA. Ability to egress is a
consideration unto itself. There are permit required and non-permit required confined spaces. (I never liked that
terminology as they both require permits). IDLH atmospheres are permit required.

Roger, I've been reading your posts here for years and you have my respect. It seems as we both have some job
related experience with confined space entries. I've been doing it for 28 years and I sure don't consider myself an
expert on the subject. But please help educate me. Why did the victim go into convulsions instantly if he was
suffocating and why did it take months for him to recover? Like I said, I am not an expert on this, I'm only
relating my experiences. And in my experience nitrogen can be deadly even without being pressurize and without
"suffocating" you. And yes I know that air is 78% nitrogen.

Nor am I an expert on the subject either, but with similar time in the
field (26 years) before going back to college, but I stress that was
nearly 20 years ago.

"My Guess" which is all I can do from here, is there may have been
some traces of something other than N2 there. BUT as has been
mentioned, loss of consciousness is quite rapid in a pure N2
atmosphere. It's not usually instantaneous but quick. More like 5
to10 seconds which is about the time it takes for the process of
"removing" O2 from the blood in the lungs and the oxygen depleted
blood reaching the brain. However from my training (which was a long
time ago) the convulsions appear very soon, or almost as soon as the
loss of consciousness.

"My understanding" which could be flawed both by time and changes in
industry understanding since I left:

Our lungs work based on the "partial pressure" of O2 in the air. When
the partial pressure of O2 in the air is normal the lungs pass O2 into
the blood where the red blood cells bind the molecules of Oxygen and
carry it to where it is needed. Just about the first location being
the brain.
When the partial pressure drops below a given value (I've forgotten
the actual value) the lungs cease to pass the O2 into the blood
stream. Only a slight decrease from that point will cause the process
to reverse. Two things will cause this. remove the O2 from the
atmosphere and/or reduce the atmospheric pressure. This is the reason
why breathing pure O2 at high altitudes using a canula doesn't work.
You need the pressure of a mask.

OTOH blood that has had the O2 removed has an effect on the brain that
is quite different than Oxygen starved blood. It really messes with
the brain and does so quickly which accounts for the rapid onset of
convulsions. It's my understanding that the onset of brain damage is
also much faster as the blood is actually scavenging Oxygen from those
cells. The whole system has been thrown into reverse. The drop in O2
in the brain causes the neurons to start firing randomly which of
course results in convulsions.

That makes getting not just fresh air, but pure O2, to the patient as
quickly as possible, *essential* as you only have a small fraction of
the time normally available that you would have in the case of
asphyxiation. Even when pure O2 is applied you not only have to get
the amount of O2 in the blood up to normal, but it has to re oxygenate
areas that have less than normal amounts of O2, maybe way less. That
means the lungs themselves are going to be using up the O2 for a short
time before there is enough to supply the brain and the lungs are
going to be dealing with Oxygen starved blood for some time.

The brain is supposed to be capable of lasting up to 3 minutes or
possibly more without fresh air, the time available in this case may
be less than a minute. So, it is possible that this was a case of
inhaling pure N2 which would have given him just about time enough to
put the mask back in place before going down. The convulsions would
have probably started about the time he hit the floor.

Again, though, I stress it has been a long time since I had to deal
with this stuff on a day-to-day basis and I have not kept up with it
since then. "I think" which means I don't really know for sure, but
the treatment is pure O2 as quickly as possible and then like CO
poisoning, you keep the patient still as movement can make the
situation worse if done before the blood has been completely re
oxygenate.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


I think this thread has drifted way to far off topic. For anyone else still interested go here Go here if you'd like
to read up on confined space requirements.
http://www.osha.gov/pls/oshaweb/owad...able=STANDARDS

Joe Schneider
8437R



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"Roger" wrote in message ...
snip

"My Guess" which is all I can do from here, is there may have been
some traces of something other than N2 there. BUT as has been
mentioned, loss of consciousness is quite rapid in a pure N2
atmosphere. It's not usually instantaneous but quick. More like 5
to10 seconds which is about the time it takes for the process of
"removing" O2 from the blood in the lungs and the oxygen depleted
blood reaching the brain. However from my training (which was a long
time ago) the convulsions appear very soon, or almost as soon as the
loss of consciousness.
snip

Our lungs work based on the "partial pressure" of O2 in the air. When
the partial pressure of O2 in the air is normal the lungs pass O2 into
the blood where the red blood cells bind the molecules of Oxygen and
carry it to where it is needed. Just about the first location being
the brain.
When the partial pressure drops below a given value (I've forgotten
the actual value) the lungs cease to pass the O2 into the blood
stream. Only a slight decrease from that point will cause the process
to reverse. Two things will cause this. remove the O2 from the
atmosphere and/or reduce the atmospheric pressure. This is the reason
why breathing pure O2 at high altitudes using a canula doesn't work.
You need the pressure of a mask.

OTOH blood that has had the O2 removed has an effect on the brain that
is quite different than Oxygen starved blood. It really messes with
the brain and does so quickly which accounts for the rapid onset of
convulsions. It's my understanding that the onset of brain damage is
also much faster as the blood is actually scavenging Oxygen from those
cells. The whole system has been thrown into reverse. The drop in O2
in the brain causes the neurons to start firing randomly which of
course results in convulsions.

That makes getting not just fresh air, but pure O2, to the patient as
quickly as possible, *essential* as you only have a small fraction of
the time normally available that you would have in the case of
asphyxiation. Even when pure O2 is applied you not only have to get
the amount of O2 in the blood up to normal, but it has to re oxygenate
areas that have less than normal amounts of O2, maybe way less. That
means the lungs themselves are going to be using up the O2 for a short
time before there is enough to supply the brain and the lungs are
going to be dealing with Oxygen starved blood for some time.

The brain is supposed to be capable of lasting up to 3 minutes or
possibly more without fresh air, the time available in this case may
be less than a minute. So, it is possible that this was a case of
inhaling pure N2 which would have given him just about time enough to
put the mask back in place before going down. The convulsions would
have probably started about the time he hit the floor.

Again, though, I stress it has been a long time since I had to deal
with this stuff on a day-to-day basis and I have not kept up with it
since then. "I think" which means I don't really know for sure, but
the treatment is pure O2 as quickly as possible and then like CO
poisoning, you keep the patient still as movement can make the
situation worse if done before the blood has been completely re
oxygenate.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Thanks Roger. I believe this "disagreement" turned into a relevant discussion and good learning experience, (at
least for me). I wish all newsgroup threads would follow this example. The ERT did try and start high flow oxygen
on the victim as the first priority, however he was so combative that he kept knocking the nasal canula/mask, off.
(I can't remember which was used, perhaps both. This incident happened circa 1999). He was physically restrained and
tied down in a stokes basket on a back board while one guy held the mask in place as best he could.

From what I've gleaned from the discussion I still wouldn't consider nitrogen poisoning a true "poisoning". I can't
really say I'd consider it suffocation either, at least as I previously viewed suffocation. And if you type
"definition of toxic" in Google and peruse what comes up you can argue all day long whether nitrogen is toxic and
both sides could be considered correct. There is much more to this oxygen, carbon dioxide exchange than I was aware
of. And it amazes me that the exchange works fine when breathing in air that contains 78% nitrogen and 21% oxygen...
but in atmospheres containing less than 19% O2 we start starving for oxygen and at some point the exchange actually
reverses and O2 is stripped from the body? The older I get the less I know! And how in the heck we went from medal
winners: ATC tapes to this!

I'm headed to the airport. It's pretty outside!

Joe Schneider
8437R




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Might we go a bit farther?

The reason I ask is that I've seen people take big lungfuls of Helium,
which (obviously) doesn't produce the same effect.

Can someone explain why N is such a disaster but He doesn't?

(Should have paid more attention in chemistry classes!)


Richard

On Sun, 05 Feb 2006 17:50:04 GMT, Richard Lamb
wrote:

Might we go a bit farther?

The reason I ask is that I've seen people take big lungfuls of Helium,
which (obviously) doesn't produce the same effect.

A really big lung full can make you light headed in a hurry, but
beyond that?


Can someone explain why N is such a disaster but He doesn't?

"I think" it has to do with the partial pressure of He compared to N,
but I really don't know. There are warnings about inhaling He, but
I've not heard of any reactions like those of N2. Still, He is used
as an N2 replacement in diving air at times to reduce the likely hood
of getting the bends on deep dives.

There *must* be some one who reads this group who knows.


(Should have paid more attention in chemistry classes!)

I should have gotten better grades!

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com



Richard

JJS wrote:
...

From what I've gleaned from the discussion I still wouldn't consider nitrogen poisoning a true "poisoning". I can't
really say I'd consider it suffocation either, at least as I previously viewed suffocation.

I think the proper term is asphyxiation.

--

FF

Roger wrote:
On Sun, 05 Feb 2006 17:50:04 GMT, Richard Lamb
wrote:

Might we go a bit farther?

The reason I ask is that I've seen people take big lungfuls of Helium,
which (obviously) doesn't produce the same effect.

A really big lung full can make you light headed in a hurry, but
beyond that?


Can someone explain why N is such a disaster but He doesn't?

"I think" it has to do with the partial pressure of He compared to N,
but I really don't know.

Partial Pressure of a gas is what the pressure would be if all the
other gasses were removed without changing the volume.

Equal volumes of gas at the same temperature and pressure have
equal numbers of molecules (Avogadro's law). So no, that isn't
the explanation.

There are warnings about inhaling He, but
I've not heard of any reactions like those of N2.

The warnings I have heard regard hydrocarbon contaminants
like compressor oils, putting the huffer at risk for chemical
pneumonia.

Still, He is used
as an N2 replacement in diving air at times to reduce the likely hood
of getting the bends on deep dives.


One presumes contaminants like compressor oils are filtered out
when the Helium is intended for that purpose, something one might
not bother to do for balloons.

--

FF