Re: Can welding Oxygen be used in place of medical oxygen?

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HeyBub

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Jun 19, 2010, 8:52:45 AM6/19/10
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LSMFT wrote:
>
> Seems like my dad had a machine that created (or condensed) oxygen
> from the air for him to breath. No bottles to change.
> Why can't they do that for welding?

Large scale O2 generation involves cooling air to liquify it, then pulling
off the components: Oxygen, Nitrogen, CO2, Argon, etc.

You CAN get Oxygen by electrolysis of water (plus Hydrogen), but the energy
expenditure is horrendous.

Certainly O2 generators can be powered by chemical means; the Oxygen masks
on airliners rely on chemical release of O2 by the burning of chlorates or
perchlorates.

All that said, you can get O2 generators for small applications (bedside,
veterinary, etc.) use, up to, and including, institutional generation, say,
for hospitals.

To answer your question directly: Bottled O2 is far cheaper than the
alternatives.


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Doug Miller

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Jun 19, 2010, 9:01:18 AM6/19/10
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In article <SK2dnRfBjvQiJ4HR...@giganews.com>,
Steve Barker <ichasepa...@notgmail.com> wrote:
>On 6/18/2010 8:58 PM, Some Guy wrote:
>> Is there any difference between a tank of welding oxygen vs medical
>> oxygen as far as purity, concentration, hazardous impurities, etc, that
>> would render welding oxygen insufficient (or even dangerous) for helping
>> to supplement breathing / respiration ?
>
>it's the same.
>
Ummm..... no, it's not. Read the other responses in this thread from people
who actually know the difference.

AZ Nomad

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Jun 19, 2010, 9:25:46 AM6/19/10
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On Sat, 19 Jun 2010 07:40:35 -0500, Steve Barker <ichase...@notgmail.com> wrote:
>On 6/18/2010 8:58 PM, Some Guy wrote:
>> Is there any difference between a tank of welding oxygen vs medical
>> oxygen as far as purity, concentration, hazardous impurities, etc, that
>> would render welding oxygen insufficient (or even dangerous) for helping
>> to supplement breathing / respiration ?

>it's the same.

no it isn't

Jay Hanig

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Jun 19, 2010, 9:33:55 AM6/19/10
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On 6/18/2010 11:56 PM, Some Guy wrote:
> AZ Nomad wrote:
> Even welding supply stores will stock only "medical grade" oxygen?
>
> You people might want to read this:
>
> http://www.avweb.com/news/pelican/182079-1.html

*That* was a great article. The writer has great credibility to my
mind, as I am a registered nurse, former scuba instructor, and former
commercial pilot. I thought I knew a lot about oxygen. It turns out I
wasn't as well informed as I had assumed.

You guys really need to read this if you're interested in compressed
oxygen in any form.

Jay

Harry K

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Jun 19, 2010, 10:43:10 AM6/19/10
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On Jun 18, 9:47 pm, "Ed Pawlowski" <e...@snetnospam.net> wrote:
> "Some Guy" <S...@Guy.com> wrote in messagenews:4C1C41BB...@Guy.com...
> > Ed Pawlowski wrote:
>
> >> Certification.  Medical oxygen has to be certified to a certain
> >> purity, welding does not.
>
> > How exactly can compressed oxygen be "impure" ?
>
> > Are some oxygen molecules more pure than other oxygen molecules?
>
> The content of bottled oxygen is not 100% pure.  It is 99.xxx% pure.  That
> other tiny amount can be anything in the atmosphere or it can be some
> contaminant from the bottle.    I used to work with medical oxygen and every
> batch had a certification giving the purity.
>
>
>
> > Or does the Medical oxygen tank look nicer and cleaner than the Welding
> > oxygen tank?
>
> >> You pay for that test and the potential liability that goes
> >> along with it.
>
> > I think you pay more for medical and aviation O2 because the
> > consequences can be more expensive if there is a problem with the
> > product (the product being compressed oxygen).
>
> That is what I just said above.
>
> >The product itself is no
> > more expensive or different or has any additional processing steps done
> > to it on the basis of it's sale in it's variously-labelled forms.
>
> It has a step that does not have to be taken with welding oxygen.
> Certification.  O2 tanks have been contaminated in the past.  Rare, but it
> has happened.   Filling my own tanks, I'd not be concerned about using
> welding oxygen, but I'm not so quick to grab a tank off the back of a truck
> at a job site and start breathing it.  If you get the certification with
> welding grade, then it is the same.  That piece of paper is worth a lot of
> money if there ever was a problem.

One must differentiate between the "oxygen" tanks (that contain pure
oxygen) and the tanks used in the breathing apparatuses - those
contain just compressed air with the usual nitrogen, co2, etc. still
in it. The 'grab a tank off the back of a truck" implies tanks for
the SCBAs - air, not oxygen.

Harry K

Frank

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Jun 19, 2010, 10:49:01 AM6/19/10
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The concentrators work by reverse osmosis. You can travel with them and
use rechargeable batteries. If you are home, immobile, the medical
supplier will often give you liquid and tubing is strung around the
house. For short trips of a few hours, you can take liquid. You hire a
supplier and it is up to him to satisfy all your requirements, tank,
liquid or concentrator.

dpb

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Jun 19, 2010, 10:48:21 AM6/19/10
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Some Guy wrote:

> Tom Horne wrote:
>
>>>>> Is there any difference between a tank of welding oxygen vs
>>>>> medical oxygen (...)
>
...

>
> From what I've been reading tonight, ALL forms of compressed oxygen
> (Aviation, Medical, Welding) come from the SAME source (a tank of Liquid
> Oxygen - LOX) and are transfered to variously labelled tanks and charged
> various prices based on the label on the tank.
...

> So the bottom line is that if you walk into a welding supply store to
> buy an oxygen tank, don't let on that you intend to use it to fill your
> plane's on-board tank, or you want to make an oxygen tent for your sick
> pet. ...

The bottom line is how confident do you want to be that what comes out
of that refilled tank is, indeed, fit for breathing purposes and hasn't
been contaminated since that point?

The scenario in the posting link later of a single large bottle
refilling known smaller ones is reasonably well controlled; just taking
the next random welding bottle returned from who knows where...errr, not
so much. As someone else pointed out, you don't know what was done with
those bottles previously nor what has been done since w/o the
certification--that's the role it plays.

As for cost; it's a lot like the "N-stamp" nuclear-grade
components--many of them are, in fact, identical to their non-graded
cousins but they've been through the qualifications to prove their
pedigree; the poor red-headed stepchild _may_ be just as good but
doesn't have the papers to prove it.

--


--

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Jim Yanik

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Jun 19, 2010, 11:52:45 AM6/19/10
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Some Guy <So...@Guy.com> wrote in news:4C1C3F57...@Guy.com:

> Tom Horne wrote:
>
>> > > > Is there any difference between a tank of welding oxygen vs
>> > > > medical oxygen (...)
>

>> > And just to be clear -
>> >
>> > Welding oxygen is more (way more) than just compressed "air".
>> > And what I mean by "air" is the stuff that's all around us
>> > right now.
>> >
>> > Yes?
>>
>> To be precise it is way less. The air we breath is roughly twenty
>> percent oxygen.
>
> And what I meant by "way more" was that welding oxygen has a higher
> oxygen content (or oxygen concentration) vs ordinary air. So I don't
> know why you'd say it's "way less".

it's "way less" because for a given volume of gas,you get only ONE
element;oxygen,while "air" also gives you
nitrogen,argon,helium,krypton,xenon.
Not that they have any benefit,but it's "more" than what you get with pure
O2. ;-)


--
Jim Yanik
jyanik
at
localnet
dot com

Ed Pawlowski

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Jun 19, 2010, 2:06:58 PM6/19/10
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<gfre...@aol.com> wrote
>
> If it is labeled USP, it has to be medical grade or someone will be
> sued. BTW if you go in the back of a hospital you will see "welding"
> bottles hooked up to their system.


Not only have I looked at the back of the hospital, I've hooked up the
bottles. I've also filled thousands of bottles for medical use. Every one
has a tag with the purity listed and usually a traceability batch number.
Oxygen is oxygen, but unless it has proper certification, it is not for
medical use.

The content may be the same, but the paperwork is not. Without the proper
paperwork, it is not medical grade.

jeff_wisnia

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Jun 19, 2010, 2:32:30 PM6/19/10
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gfre...@aol.com wrote:
> On Sat, 19 Jun 2010 07:46:10 -0400, "Ed Pawlowski"
> <e...@snetnospam.net> wrote:
>
>
>><gfre...@aol.com> wrote
>>
>>>I buy lots of oxygen from the welding store and the label always says
>>>USP grade. I have never seen any other kind. The answer is on the
>>>label tho.
>>
>>That is because the oxygen itself it USP grade. One difference I forgot to
>>mention. Filling procedure. You can fill a welding grade bottle by making
>>the connection, opening the valve, and filling. When filling medical
>>bottles, they must be emptied, hooked to a vacuum pump and evacuated, then
>>filled.
>>
>>Welding grade can be used in many ways by many different people. You can
>>hook it to a manifold along with other gasses. If the cylinder pressure
>>drops below what other gas on that manifold it, it can be back-fed some of
>>the other gas and contaminated.

>>
>
>
> If it is labeled USP, it has to be medical grade or someone will be
> sued. BTW if you go in the back of a hospital you will see "welding"
> bottles hooked up to their system.
> It is more expensive to have 2 types of oxygen at the welding store
> than to just have one.
> They have to watch contaminants, just for safety. In the presence of
> pure oxygen, lots of things you think are pretty safe, become
> explosive. Try some steel wool.

Fine steel wool will burn pretty darn well in air too.

About 25 years ago one of my toddlers managed to touch some fine steel
wool across the terminals of a 9 volt "transistor radio" battery which
set the steel wool ablaze. The kid wasn't harmed, but I had to replace a
kitchen floor vinyl tile. <G>

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.

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Some Guy

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Jun 19, 2010, 2:55:20 PM6/19/10
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HeyBub wrote:

> To answer your question directly: Bottled O2 is far cheaper than the
> alternatives.

The question was not if bottled O2 is cheaper than the alternatives.

The question was - are all forms or labels of bottled O2 essentially
equivalent.

Some Guy

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Jun 19, 2010, 3:13:50 PM6/19/10
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dpb wrote:

> The bottom line is how confident do you want to be that what comes
> out of that refilled tank is, indeed, fit for breathing purposes
> and hasn't been contaminated since that point?

I presume that the first time that any brand-new O2 bottle is filled
with it's first batch of O2, that it has been cleaned and vacuum
evacuated first.

After that point, unless the air pressure in that tank ever falls below
ambient atmospheric pressure, it's hard to see how anything other than
pure O2 could ever re-enter it - even if it was ever connected to a
manifold system where other bottles of similarly-clean O2 are also
connected.

> The scenario in the posting link later of a single large bottle
> refilling known smaller ones is reasonably well controlled; just
> taking the next random welding bottle returned from who knows
> where...errr, not so much.

I understand that I can buy, or rent, oxy-acetelene tanks. If I buy,
I'm not sure if I can have my bought-tank re-filled and returned to me,
or if I simply exchange it for filled (but used) tank.

If I buy a brand new tank, and if I keep refilling that same tank when I
need more, then I am removing the uncertainty of what could have been in
the tank before it was filled.

And when it comes to refilling returned tanks, is it normal practice to
at least let the tank fully depressurize itself before it's refilled?
Wouldn't that dillute any potential non-oxygen gas or even particulate
contaminent that it *may* have once the tank has been refilled with
known-pure O2?

Some Guy

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Jun 19, 2010, 3:16:40 PM6/19/10
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George wrote:

> Next time watch the significant difference on how medical use vs
> other tanks are filled. Any medical use tanks are first evacuated
> to insure there is nothing else in the tank before it is filled.

How exactly could something get into the tank in the first place?

If it's connected to a manifold system, then yes, the gas from a
higher-pressure tank could flow into it. But doesn't that
higher-pressure tank already contain known-pure O2?

If it's never connected to a manifold system or to another tank, then
how exactly could something get into it? Deliberate tampering?

Some Guy

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Jun 19, 2010, 3:22:20 PM6/19/10
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Kurt Ullman wrote:

> > Are some oxygen molecules more pure than other oxygen molecules?

> No, but other gasses can be introduced. Even the compressors for
> the regular air firefighters have to be carefully maintained. Oils,
> etc., can be introduced that cause failure of the seals.

Do compressed air suppliers have different compressors for filling
different O2 bottles from their bulk LOX source supply?

Hasn't it already been mentioned that even welding O2 gas needs to be
just as clean as medical-grade O2?

> At least for medical oxygen you pay more because the tests and
> tracking requirements of medical oxygen is more expensive.

I'm not convinced that there are any such tests.

Paperwork and barcode scanning? Yes, sure. I can see that. But unless
someone posts something indicating that such "testing" is done, then I
think it's pure speculation that there is this testing step.

> These are additional processing steps (at least the
> testing and certification).

Testing is the same as certification. So what are these additional
processing steps beyond testing?

Do you work at a compressed air supply company?

Steve Barker

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Jun 19, 2010, 4:15:35 PM6/19/10
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On 6/19/2010 7:19 AM, LSMFT wrote:

> Some Guy wrote:
>> Tom Horne wrote:
>>
>>>>>> Is there any difference between a tank of welding oxygen vs
>>>>>> medical oxygen (...)
>>
>>>> And just to be clear -
>>>>
>>>> Welding oxygen is more (way more) than just compressed "air".
>>>> And what I mean by "air" is the stuff that's all around us
>>>> right now.
>>>>
>>>> Yes?
>>>
>>> To be precise it is way less. The air we breath is roughly twenty
>>> percent oxygen.
>>
>> And what I meant by "way more" was that welding oxygen has a higher
>> oxygen content (or oxygen concentration) vs ordinary air. So I don't
>> know why you'd say it's "way less".
>>
>>> Medical oxygen is nearly one hundred percent oxygen.
>>
>> And likewise for welding oxygen - yes?
>>
>> Harry K wrote:
>>
>>> Yes there is a difference according to my first aid training (years
>>> ago). You can use in the case of emergency. It is IIRC too dry to
>>> use for extended periods (I should have paid more attention to that
>>> discussion).

>>
>> From what I've been reading tonight, ALL forms of compressed oxygen
>> (Aviation, Medical, Welding) come from the SAME source (a tank of Liquid
>> Oxygen - LOX) and are transfered to variously labelled tanks and charged
>> various prices based on the label on the tank.
>>
>> My guess is that the price differential is caused by liability insurance
>> and the need to recoup that cost based on the end-use of the gas. The
>> insurance industry might perceive that aviation oxygen (as a product)
>> carries the highest risk to the producer / seller, with medical oxygen
>> less risky, and welding oxygen the lowest risk. Risk in this context
>> means what sort of incident could happen if the wrong gas is
>> accidentially sold to the end user, or could happen if the tank fails.
>>
>> The humidity of compressed oxygen seems to be a red herring. In medical
>> situations such as the hospital bedside, oxygen supply lines are passed
>> through a bubbler or some other humidification device to add humidity to
>> the air. This is a stationary situation where the person is likely to
>> be on the air supply for an extended period, and humidification is done
>> more for comfort or to prevent airway irritation than anything else. In
>> other medical situations (EMS O2 respirator tanks) the air is dry -
>> because it simply can't supply O2 for an extended period anyways.
>>
>> And you don't want to get water in your high-pressure tanks anyways - if
>> only so they don't rust.
>>
>> Aviation air also can't contain a lot of humidity because (or so the
>> story goes) the water could freeze at high altitudes and mess up the
>> supply and metering lines.

>>
>> So the bottom line is that if you walk into a welding supply store to
>> buy an oxygen tank, don't let on that you intend to use it to fill your
>> plane's on-board tank, or you want to make an oxygen tent for your sick
>> pet. The guy behind the counter will most likely go ape-shit and either
>> deny your purchase, or force you to buy the more expensive tank -
>> probably because their insurance company forces them to do that.
>>
>> The insurance industry plays a far larger role behind the scenes in our
>> daily lives than we realize. The products we can buy, the services we
>> use, the way they are delivered or sold to us, etc, exist because the
>> manufacterers, retails or providers have reached a stable (perhaps even
>> strained) coexistance with the insurance industry.

>
> Seems like my dad had a machine that created (or condensed) oxygen from
> the air for him to breath. No bottles to change.
> Why can't they do that for welding?
>
>
>
they can and do. Most Midas muffler shops make (concentrate) their own
o2 for the oxy/acy setup.

--
Steve Barker
remove the "not" from my address to email

Steve Barker

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Jun 19, 2010, 4:17:04 PM6/19/10
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i read the responses. It's the same.

Ed Pawlowski

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Jun 19, 2010, 4:23:17 PM6/19/10
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"Some Guy" <So...@Guy.com> wrote in message news:4C1D1798...@Guy.com...

Temperature changes. If you have an open tank and let the gas inside
expand, then contract, it will draw in outside air, moisture, or whatever.
Leave that tank long enough and you can get all sorts of contamination, not
all of which is harmful, but it would still not meet medical criteria.

AZ Nomad

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Jun 19, 2010, 4:48:58 PM6/19/10
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It *can* be the same. However, oxygen graded for welding, but not
for medical use, isn't safe for medical use.

Wether or not a store sells medical grade oxygen to welders is up
to the store and not universally true.

Doug Miller

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Jun 19, 2010, 6:08:18 PM6/19/10
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So the people who said it's not the same are wrong?

Jim Yanik

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Jun 19, 2010, 7:39:41 PM6/19/10
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spam...@milmac.com (Doug Miller) wrote in
news:hvjf4r$2e4$1...@news.eternal-september.org:

the people who said they're different said it a long time ago when they
actually were different.
Times have changed,they no longer actually are different.

did you not read the article cited? it was very informative.

HeyBub

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Jun 19, 2010, 7:57:34 PM6/19/10
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If the other tank contained, say, acetylene.


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Doug Miller

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Jun 19, 2010, 10:02:39 PM6/19/10
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Uh-huh. Right. Welding oxygen is certified just as pure as medical oxygen, no
contaminants. Suuuurrrrre it is. That's why they use welding oxygen in
hospitals.

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Pete C.

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Jun 19, 2010, 11:27:17 PM6/19/10
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The purity standard for welding O2 is higher than the purity standard
for medical O2. In reality all three normal grades you can get, welding,
medical and aviator exceed all of the standards. Only the analytical
grade is higher purity.

Pete C.

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Jun 19, 2010, 11:31:14 PM6/19/10
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Ed Pawlowski wrote:
>
> "Some Guy" <So...@Guy.com> wrote in message news:4C1C41BB...@Guy.com...

> > Ed Pawlowski wrote:
> >
> >> Certification. Medical oxygen has to be certified to a certain
> >> purity, welding does not.
> >
> > How exactly can compressed oxygen be "impure" ?
> >
> > Are some oxygen molecules more pure than other oxygen molecules?
>
> The content of bottled oxygen is not 100% pure. It is 99.xxx% pure. That
> other tiny amount can be anything in the atmosphere or it can be some
> contaminant from the bottle. I used to work with medical oxygen and every
> batch had a certification giving the purity.
>
> >
> > Or does the Medical oxygen tank look nicer and cleaner than the Welding
> > oxygen tank?
> >
> >> You pay for that test and the potential liability that goes
> >> along with it.
> >
> > I think you pay more for medical and aviation O2 because the
> > consequences can be more expensive if there is a problem with the
> > product (the product being compressed oxygen).
>
> That is what I just said above.
>
> >The product itself is no
> > more expensive or different or has any additional processing steps done
> > to it on the basis of it's sale in it's variously-labelled forms.
>
> It has a step that does not have to be taken with welding oxygen.
> Certification. O2 tanks have been contaminated in the past. Rare, but it
> has happened. Filling my own tanks, I'd not be concerned about using
> welding oxygen, but I'm not so quick to grab a tank off the back of a truck
> at a job site and start breathing it. If you get the certification with
> welding grade, then it is the same. That piece of paper is worth a lot of
> money if there ever was a problem.
>
>

Medical 99.95% pure
Welding 99.99% pure

AZ Nomad

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Jun 20, 2010, 12:24:19 AM6/20/10
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On Sat, 19 Jun 2010 22:27:17 -0500, Pete C. <aux3....@snet.net> wrote:

>The purity standard for welding O2 is higher than the purity standard
>for medical O2. In reality all three normal grades you can get, welding,
>medical and aviator exceed all of the standards. Only the analytical
>grade is higher purity.

Nope. Why don't you look it up, starting with 1) the percentage of oxygen
and ending with 2) the levels of impurities.

You can't use welding O2 for medical purposes but you can use medical O2
for welding.

Jay Hanig

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Jun 20, 2010, 2:24:42 AM6/20/10
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On 6/19/2010 10:02 PM, Doug Miller wrote:

> Uh-huh. Right. Welding oxygen is certified just as pure as medical oxygen, no
> contaminants. Suuuurrrrre it is. That's why they use welding oxygen in
> hospitals.


There is a LOT of shit done in hospitals simply because that is the way
they've always done it. To suggest otherwise to them will get you a
look that suggests you've lost your mind.

I deal with policies all the time that closer examination would reveal
are outdated and kind of stupid if you consider the current realities.
But the Powers That Be know what they know and nobody can tell them
different. So we still do what we've always done.... because we've
always done it that way.

A lawyer would probably make a big deal about "welding" oxygen instead
of USP in much the same way the US Navy made a big deal about the
captain of the USS Indianapolis not zigzaging when his ship was
torpedoed. The commander of the Japanese submarine testified at his
court martial that it wouldn't have mattered one way or the other; he
still would have nailed him. The Navy didn't care... because policy
stated you should always zigzag when submarines might be around. After
all, they'd always done it that way.

Many of the folks who determine these policies are dinosaurs, and about
as current.


Jay

Jay Hanig

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Jun 20, 2010, 2:27:57 AM6/20/10
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On 6/19/2010 8:05 PM, gfre...@aol.com wrote:

> Acetylene in an oxygen tank is a bomb.
> It could get contaminated by bacteria from the "breathing" that
> happens when you leave the valve open but most real welders will turn
> the tank back in with a little pressure in it, Same for SCUBA folks.


You typically never allow the pressure to drop to zero because higher
pressure in the tank is the only way to keep ambient moisture from
entering the tank. Ultimately it's to keep the tank from rusting on the
inside.


Jay

Ed Pawlowski

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Jun 20, 2010, 7:46:16 AM6/20/10
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"Jay Hanig" <jayh...@charter.net> wrote in message
news:NxiTn.32956$yx.1...@newsfe13.iad...

That is exactly why medical oxygen thanks have to be evacuated. Rare that
one would come back with any pressure at all.

George

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Jun 20, 2010, 8:45:47 AM6/20/10
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On 6/19/2010 8:19 AM, LSMFT wrote:
> Some Guy wrote:
>> Tom Horne wrote:
>>
>>>>>> Is there any difference between a tank of welding oxygen vs
They do and they aren't an unusual thing at all to find in a low-medium
usage shop.

Some Guy

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Jun 20, 2010, 8:54:19 AM6/20/10
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Ed Pawlowski wrote:

> > You typically never allow the pressure to drop to zero because
> > higher pressure in the tank is the only way to keep ambient
> > moisture from entering the tank. Ultimately it's to keep the
> > tank from rusting on the inside.

> That is exactly why medical oxygen thanks have to be evacuated.
> Rare that one would come back with any pressure at all.

I would think the contrary.

O2 tanks used by hospitals are more likely to be part of a manifold
system, and as such will always be maintained at some positive pressure
by virtue of the fact that at least one of their "gang-mates" is likely
to have enough excess pressure to keep them partially pressurized.

If a gang of O2 tanks at a hospital collectively fall below some
acceptible level of pressure, then they're no longer useful as an air
souce and MUST be changed out. So again the argument here is that
medical O2 tanks are MORE likely to be returned while still containing
some positive pressure charge.

If the strongest argument so far is that a "medical-grade" tank of O2
has lived it's life with minimal to zero infiltration of atmospheric
humidity (or even nitrogen) compared to a welding tank, then that's a
pretty weak argument to say that a tank of welding O2 is unhealthy to
breath. Last I checked, we all take in some some water vapor and
nitrogen when we breath standard air.

In other words, a lack of "purity" does not equal unhealthy or hazardous
for human breathing. A lack of purity (it seems) will degrade welding
performance, maybe mess up equipment, etc.

And so far, it's just been pure speculation here that tanks of welding
O2 are *not* evacuated prior to filling, just as supposedly medical
tanks are.

Some Guy

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Jun 20, 2010, 8:58:31 AM6/20/10
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AZ Nomad wrote:

> Nope. Why don't you look it up, starting with 1) the percentage
> of oxygen and ending with 2) the levels of impurities.

Like I just said, the presence of impurities does not necessarily equate
to medical safety or have a health impact. If those impurities are
nitrogen or water vapor, then what exactly are the health implications
of those? We freeking breath them all the time - in concentrations
several orders of magnitude higher than what could possibly exist in a
tank of welding O2.

> You can't use welding O2 for medical purposes

Says who?

A lawyer? Or a biochemist?

Some Guy

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Jun 20, 2010, 9:03:21 AM6/20/10
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"Pete C." wrote:

> Medical 99.95% pure
> Welding 99.99% pure

Here's the problem I have with that.

What is the compressed gas supplier doing differently that would result
in that very slight (but consistent?) difference between those two
products?

If he has two machines or processes for creating the two products
(welding O2 and medical O2) and if the welding O2 product is more
"pure", then why would he operate two processes instead of simply using
a single process (the higher purity process) to create *both* of them?
Especially since the welding product is retailed at a lower price to
start with.

The Daring Dufas

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Jun 20, 2010, 9:10:08 AM6/20/10
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I can see a huge LOX tank next to a main traffic artery in the Southside
neighborhood of Birmingham where UAB Hospital is located. Tanker trucks
pull up next to the thing and fill it on a regular basis. The
maintenance guys who work for the complex tell me there are tunnels all
around under the place filled with all sorts of conduits and pipes that
distribute various electrons, liquids and gases that keep the hospital
alive. I imagine that LOX tank supplies O2 to the whole hospital and
perhaps a couple of different hospitals in the same general area. The
hospitals share doctors, why not oxygen?

TDD

Some Guy

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Jun 20, 2010, 9:32:14 AM6/20/10
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The Daring Dufas wrote:

> I can see a huge LOX tank next to a main traffic artery in the
> Southside neighborhood of Birmingham where UAB Hospital is located.

LOX is a different situation. It requires a cryogenic storage tank, and
perhaps on-site re-compression to boost the pressure of the O2 that's
vaporized from the LOX as needed.

We're talking about the bottled O2 that's sold under variously-labelled
end-uses by the compressed gas retailer, and whether or not there's any
*real* negative health implications when using welding O2 gas instead of
"medical" O2 gas in a residential setting.

The Daring Dufas

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Jun 20, 2010, 10:03:14 AM6/20/10
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It wouldn't surprise me if the LOX tank is used to fill portable tanks
for patient use. I'll have to ask one of my friends who works
maintenance at the hospital.

TDD

Message has been deleted

Ed Pawlowski

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Jun 20, 2010, 11:19:53 AM6/20/10
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"Some Guy" <So...@Guy.com> wrote

>> That is exactly why medical oxygen thanks have to be evacuated.
>> Rare that one would come back with any pressure at all.
>
> I would think the contrary.
>
> O2 tanks used by hospitals are more likely to be part of a manifold
> system, and as such will always be maintained at some positive pressure
> by virtue of the fact that at least one of their "gang-mates" is likely
> to have enough excess pressure to keep them partially pressurized.


You think wrong. Medical oxygen is used in many places aside from
hospitals. Thousands of bottle every day are used in private homes. They
are single size, no manifolds, They are generally used until empty.
Valves are left open, regulators removed. They are sometimes stored in poor
environments, must basements, trunk of a car, under the sink, laundry room.

>
> If the strongest argument so far is that a "medical-grade" tank of O2
> has lived it's life with minimal to zero infiltration of atmospheric
> humidity (or even nitrogen) compared to a welding tank, then that's a
> pretty weak argument to say that a tank of welding O2 is unhealthy to
> breath. Last I checked, we all take in some some water vapor and
> nitrogen when we breath standard air.
>
> In other words, a lack of "purity" does not equal unhealthy or hazardous
> for human breathing. A lack of purity (it seems) will degrade welding
> performance, maybe mess up equipment, etc.
>

> And so far, it's just been pure speculation here that tanks of welding
> O2 are *not* evacuated prior to filling, just as supposedly medical
> tanks are.

Not speculation. I've filled tanks. I followed the regulations.

Steve B

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Jun 20, 2010, 11:29:03 AM6/20/10
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"Ed Pawlowski" <e...@snetnospam.net> wrote in message
news:FrCdnTzS_flU1oHR...@giganews.com...

When I was a commercial deep sea diver, the oxygen we used in decompression
chambers was the same oxygen that we used for OA cutting. We did not use
medical oxygen.

Steve

visit my blog at http://cabgbypasssurgery.com

A fool shows his annoyance at once, but a prudent man overlooks an insult.


Ed Pawlowski

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Jun 20, 2010, 11:38:35 AM6/20/10
to

"The Daring Dufas" <the-dari...@peckerhead.net> wrote

>
> It wouldn't surprise me if the LOX tank is used to fill portable tanks
> for patient use. I'll have to ask one of my friends who works maintenance
> at the hospital.
>
> TDD

LOX tanks fill LOX tanks. They can be filled for patient use of that is
what their supplier gives them. They are a different setup that using
compressed O2 though. Different tanks, regulators, etc. They are not
usually filled at hospital though, but by independent providers.

Compressed tanks either need mechanical pumps or, most home medical
suppliers use a cascade system of tanks increasing pressure into the smaller
tanks with each on up the line.

Kurt Ullman

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Jun 20, 2010, 11:44:00 AM6/20/10
to
In article <PaqdnW9SZ7YKrIPR...@giganews.com>,
"Ed Pawlowski" <e...@snetnospam.net> wrote:

>
> You think wrong. Medical oxygen is used in many places aside from
> hospitals. Thousands of bottle every day are used in private homes. They
> are single size, no manifolds, They are generally used until empty.
> Valves are left open, regulators removed. They are sometimes stored in poor
> environments, must basements, trunk of a car, under the sink, laundry room.

Which is why there are requirements for cleaning the tanks before
filling. After that, you are on your own. Same with medicines, etc. They
have to be manufactured and stored pre-patient to certain conditions.

>
> > And so far, it's just been pure speculation here that tanks of welding
> > O2 are *not* evacuated prior to filling, just as supposedly medical
> > tanks are.
>
> Not speculation. I've filled tanks. I followed the regulations.
>
>

Interestingly enough, this thread has gone on for as long as it has
w/o anyone mentioning the main danger of non-medical oxygen... That the
insurance company won't pay for it (g).

--
I want to find a voracious, small-minded predator
and name it after the IRS.
Robert Bakker, paleontologist

Pete C.

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Jun 20, 2010, 11:45:20 AM6/20/10
to

Nope, exactly the opposite.

Ed Pawlowski

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Jun 20, 2010, 11:47:13 AM6/20/10
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"Some Guy" <So...@Guy.com> wrote

> Like I just said, the presence of impurities does not necessarily equate
> to medical safety or have a health impact. If those impurities are
> nitrogen or water vapor, then what exactly are the health implications
> of those?

But if the analysis does not say what the impurities are, you are trading on
dangerous ground. That welding tank may have been used along with any
other gas used in industrial environments.


>
>> You can't use welding O2 for medical purposes
>
> Says who?
>
> A lawyer? Or a biochemist?

Lawyers and other sensible people that do not know what other gas may be in
there. Oxygen falls into the same type of situation ad drugs. The active
ingredients of a pill are often a small percentage of the tablet, the rest
being inert ingredients. There are regulations on what those inert
ingredients can be. There are regulations on how they are handled.

If I was dying in an emergency situation from lack of oxygen, I'd grab any
tank available. If I was at home with COPD, I'd want to be sure that tank
was handled in a proper manner and would not make me worse off.

Pete C.

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Jun 20, 2010, 11:49:21 AM6/20/10
to

They aren't doing anything different, those are the *standards*, not the
actual product spec. The reality is that both grades (actually four
since there is an "aviator" grade and an "analytical" grade as well) are
filled from the same cryo tanks and both exceed the 99.99% welding grade
standard. Only the analytical grade gets extra attention to ensure it is
99.999% pure.

Pete C.

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Jun 20, 2010, 11:50:45 AM6/20/10
to

I've seen this as well, just one big rack of "welding" O2 cylinders,
grab one for cutting, or grab one for the hyperbaric chamber, all the
same.

Pete C.

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Jun 20, 2010, 11:53:57 AM6/20/10
to

Doug Miller wrote:
>
> In article <SK2dnRfBjvQiJ4HR...@giganews.com>,
> Steve Barker <ichasepa...@notgmail.com> wrote:
> >On 6/18/2010 8:58 PM, Some Guy wrote:
> >> Is there any difference between a tank of welding oxygen vs medical
> >> oxygen as far as purity, concentration, hazardous impurities, etc, that
> >> would render welding oxygen insufficient (or even dangerous) for helping
> >> to supplement breathing / respiration ?
> >
> >it's the same.
> >
> Ummm..... no, it's not. Read the other responses in this thread from people
> who actually know the difference.

Yes, it's the same. Anything to the contrary is "urban legend" or hype
for the purpose of charging more for the same stuff. All the O2 grades,
including the five nines analytical grade are filled from the same cryo
tanks, and only the analytical grade gets any extra testing to ensure
the 99.999% spec. The reality is that the welding O2 purity standard
(99.99%) is higher than the medical O2 purity standard (99.95%), and
that the actual product from the gas suppliers exceeds those purity
standards by a wide margin.

Pete C.

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Jun 20, 2010, 11:57:37 AM6/20/10
to

As has been noted many times already, the welding grade purity standard
is higher than that for the medical grade. People who do not know
anything about welding think it's some low standards dirty process, but
that is simply not the reality. Impurities in O2 that are harmless for
human use, will cause welds to fail inspections.

Welding O2 standard 99.99% pure O2
Medical O2 standard 99.95% pure O2

The reality is that the actual product in the cylinders is closer to
99.999% pure, the analytical grade standard.

AZ Nomad

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Jun 20, 2010, 11:57:57 AM6/20/10
to

>Nope, exactly the opposite.

Your assertion is in direct opposition to purity standards especially
those regarding impurities.

Why don't you make a slight attempt to educate yourself?

Pete C.

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Jun 20, 2010, 1:25:27 PM6/20/10
to

Why don't you do some research? I actually use O2 regularly, both for
welding / cutting as well as for breathing and nitrox blending. I'm well
aware of the fact that the welding O2 purity standard is tighter than
the standard for medical O2, as well as the fact that all grades of O2
from any of the large gas suppliers exceeds both the welding and medical
purity standards by a significant margin.

Pete C.

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Jun 20, 2010, 1:28:09 PM6/20/10
to

You're stuck on old paranoia based on information that is decades out of
date. All of the O2 purity grades specify no more than 0.05% impurities,
and the most lax of the standards is the medical / aviator grade. The
reality is that all the grades are filled from the same cryo O2 source
and all are better than 99.99% pure O2.

Message has been deleted

AZ Nomad

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Jun 20, 2010, 2:16:28 PM6/20/10