From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: HC-12a
Message-ID: <31saim$rrj@mozo.cc.purdue.edu>
Date: 5 Aug 1994 03:10:14 GMT
Organization: Purdue University Engineering Computer Network
Lines: 77

In article <Ctzt22.FuB@icdc.delcoelect.com>
tvmyers@koicds01.icdc.delcoelect.com (Thomas V. Myers) writes:

>Bruce G Bostwick (llbgb@utxdp.dp.utexas.edu) wrote:
>> I always have to laugh when I hear the oft-repeated concerns about HC-12a
>> being flammable ... If I get in a wreck bad enough to release the
>> refrigerant from my A/C, I'm going to be *much* more worried about the 20
>> gallons of *much* more flammable and/or _EXPLOSIVE_ gasoline under me
>> than I am about a few liters of propane/butane mix.
>>
>> Besides, don't R-12 and R-134a both turn into *seriously* toxic stuff when
>> they get hot?  I'd almost rather the refrigerant catch fire ...
>
>It's almost trivial to puncture the condensor in a relatively minor
>collision.  It's hanging out there barely behind your bumper.  It's even more
>fun when somebody with no brakelights stops in front of you at night.  You
>hit their rear end, rupturing your condensor AND shattering one or both
>headlights leaving hot filaments hanging in the breeze blowing out of the
>condensor.  Propane + hot filament = torch.  Pressure drops, flame flashes
>back inside the condensor, BOOM.

Gasoline, methane, ethane, propane, butane, pentane, hexane, heptane,
octane, nonane .. asphaltane.. are all hydrocarbons, and all have 
roughly the same upper and lower limits of flammability in air..
Roughly 2-8% in air by volume, or they will not even burn.
It is the vapor which "burns".. Gasoline == (pentane thru nonane
blend of hydrocarbons + detergents + octane boosters, etc)
Heavier hydrocarbons have more heat of combustion once they are
ignited.

The biggest danger from ANY hydrocarbons (propane or gasoline), is to
let a bunch of it out and have it NOT ignite.. until a big cloud
of fumes form.. and then ignite it.. you will get an explosion.
Gasoline will pool under the car after a wreck, and set there 
giving off fumes.  Propane/butane refrigerant (only 1.5lb in
the total A/C).. will flash off to gas immediately, and dissapate.
One also has engine oil, brake fluid, dripping on hot manifolds,
forming explosive vapor..  Approx 4-5 Qt of oil @ ~5lb/gal so
there is  more than refrigerant..

Say, you still manage to ignite the propane leaking out of the
condensor, the fire will stay 1-2 feet away from the leak..
as the propane which is closer is moving faster than the flame
propagation speed and even if the flame did reach the condenser,
it will not "blow up".. since it would have to contain 92-98%
air (2-8% propane/butane) to burn back inside the condenser
and explode (same goes for lighting off hair spray, etc)


R-12 systems contain about 8-12oz of "mineral" oil, which is not
all that flammable.. but when mixed with R-12, and a "blowout"
happens (in a wreck).. the R-12 blows out oil, and the R-12
flashes to vapor immed.. leaving an oil aerosol or fog.  This
fog is very flammable.  We have made 10 foot diameter "fireballs"
with just a couple of oz of R-12/oil mixtures

>Gasoline generally doesn't explode within the tank.  If the fuel lines are
>broken or the tank is ruptured, it goes all over and burns VERY hot, but so
>does propane/butane.  Exploding gas tanks are stuff for movies and NBC.

This is true.

There is much much more gasoline than refrigerant in a car. Exploding
air conditioners are for generating "fear" in the public to achieve
some other end.. such as deciding to buy a new car instead (with R-134a)..
There is SOME risk with hydrocarbon refrigerants, just like R-12/oil..
50,000 things had hydrocarbon refrigerants last year.. and there were
no reported "safety" incidents from all that.. Hydrocarbons are a MUCH
GREATER RISK to the pocketbooks of the automakers, and the chemical
companies.. since they are so cheap, there is no money to be made on them.
By keeping old cars running (with A/C).. Billions of $$$ of premature 
new car sales are prevented...you go figure...


--ghg

From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: HC-12a replacement for R-12
Message-ID: <3p6b2a$jne@mozo.cc.purdue.edu>
Date: 15 May 1995 01:34:02 GMT
Organization: Purdue University Engineering Computer Network
Lines: 95

In article <3p2rso$klj@newsbf02.news.aol.com> gblessing@aol.com
(GBlessing) writes:

 >No legal problem. The shit is just explosive thats all. You have to be an
 >idiot to put that crap in a customers car and even more of an idiot to put
 >it in a car that someone you love drives.
 >                                    J Blessing ASE Master Tech/Florida A/C
 >Tech

There have been reports of R-134a explosions in cars.  R-134a is
flammable/explosive at 5 PSIG above atmospheric..  Suppose some Dodo gets
a bunch of of air in the system (no vac, suction leak, etc).. and most
of the air will end up trapped in the condenser (under pressure)..
A wreck, other car fire, electrical short into a refrigerant line, etc
could set it off.

Heard of a police car (R-134a) in a minor wreck which blew the front of
the car off.. no fire..

Almost all HFC's and HCFCs (incl R-22) have flammability limits,
when mixed with air under pressure.. in real life, accidents of
this type are very rare.  50,000 "things" had OZ-12 (propane/butane) in 
them and I have heard of no "safety" related problems.. until somebody
"rigged" tests (dumping cans of it loose inside a car, carefully
mixing it with air (fan).. and igniting it to force an explosion...
took several tries.. film at 11.. national "fire/explosion" scare
results (people believe it!).. and it was nearly 100% effective.

Any refrigerant mixed with oil (oil is approx 10-15% of refrigerant
in vol).. and is blown out in a rupture can form an oil aerosol
(fog).. which can be as explosive as gasoline.. I know of safety
testing labs which have generated 10 ft fireballs from just a couple
of oz of R-12 and oil!

All kinds of other flammables, starting with 100+ lbs of gasoline,
oil, brake fluid, propane/butane "tire inflators" which inject
propane/butane into tires which already have air in them
(== bomb by defination).. You don't hear very many bitching
about those... e.q. tire infaltors do not prevent the sale
of new cars like R-12 substitutes do.


Nothing is completely without risks..various risks have to 
be evaulated through scientific methods and testings and
through experience.. not somebody screaming "this shit is
explosive..."  Propane, butane, etc, will only burn of
they are mixed with air in a ratio of 2-8% (by vol of the
hydrocarbon).. An "explosion" only results over even narrower
limits yet..  Anything else.. no fire..

The organizations which scream "fire...." about flammable refrigerants
often have ulterior motives....

They could also try presenting the following arguments to the public about
hydrocarbon refrigerants (OZ-12, HC-12a, etc)...

1) Materials cost per recharge is only $.50... There is no
money to be made in service or distribution of the product..
Where R-134a recharges sometimes fetch $300... + new drier..
No drier is needed for HC refrigerants..

2) HC refrigerants provide good lubrication and oil miscibility..
Eliminates the need for R-134a/PAG oil... so companies which
have vested interests in these would suffer..

3) HC refrigerants do not have to be recycled/reclaimed...
so the recover/reclaim/recycle industry loses out on the
gravytrain...

4) If R-12 substitutes and HC refrigerants came into widespread
use.. Then there is no need for R-134a..  R-134a retrofits with
PAG oil can be unstable chemistry (oil breakdown from residual
R-12 chlorides, etc).. can make a mess  of the system, resulting
in the need for a complete system change out ($1800-$2000) incl
labor.. Most will just trade for new car.. Assuming 1/3 trade
for new car.. approx 150million R-12 cars.. that is 50,000,000
cars @ $10,000/per car (low).. or $500,000,000,000 in
new car sales over and above normal...substitutes would eliminate
this "windfall"...

------
Think about this risk.. With all the hurdles thrown at replacement
refrigerants in general, lots of people are not going to buy
new cars.. How many folks in AZ, FL, TX, etc might die from
heatstroke, et al, if they lose A/C and cannot afford a new
car to get A/C... 
-----

Wonder why the industry just "screams fire" instead of talking
about 1)-4) above??? As former Senator Sam Steiger says...
"It is all about money".. "Just follow the money and you will
have the answer"..

Go figure.
--ghg

http://ghg.ecn.purdue.edu

Newsgroups: sci.engr.heat-vent-ac
Subject: Re: R-22 replacement?
Date: 2 Jul 1995 15:19:15 GMT
Message-ID: <3t6ddj$5is@mozo.cc.purdue.edu>
Organization: Purdue University Engineering Computer Network
Lines: 27

In article <3t68ct$52o@panic.primenet.com> n7tcf@primenet.com writes:
>	Propane meets most of those. I would not like to be the next
>serviceman to apply a torch to a system with propane in it. I have such
>systems where I work and fortunately they haven't need repair.

Good service technique means using dry nitrogen or equiv flowing
through a system when brazing.  Propane needs to be mixed with 
92-98% air to "burn".. Purge with dry nitrogen through and no problems.
As long as the system isn't full of air, there will be no 
"internal" explosion even if still full of propane at 1ATM pressure.

We use isopentane (flammable hydrocarbon), boils at 75F or so, 
in place of R11 for flush to clean up burnouts.. As long as one
is aware of the dangers and takes appropriate precautions, no
problems. (dry nitrogen purge, vent the flush outside, no sparks,
fire, smoking, etc, in the area).  $450 buys a 55gal drum of it
(grade "pure").. Sure is cheaper than 11.

The movie industry has greatly warped the public's perception of
flammables and explosions. Cars (in movies), usually have waterbeds
in the back seat & trunk filled with gasoline, and a couple of sticks
of dynamite to "disperse" and mix with air, to cause the
conflagerations so commonly seen.  Pressurizing a refrigeration
system with oxygen by mistake, will usually make a mess as bad
as seen on the movies though.

--ghg

From: ghg@freedom.ecn.purdue.edu (George Goble)
Newsgroups: rec.autos.tech
Subject: Re: HC-12a
Message-ID: <31t4k2$5tl@mozo.cc.purdue.edu>
Date: 5 Aug 1994 10:34:42 GMT
Organization: Purdue University Engineering Computer Network
Lines: 31

In article <31sarm$mak@search01.news.aol.com> jwisnia@aol.com (JWISNIA) writes:
>In article <Ctzt22.FuB@icdc.delcoelect.com>,
>tvmyers@koicds01.icdc.delcoelect.com (Thomas V. Myers) writes:
>
>>>>>>Propane + hot filament = torch.  Pressure drops, flame flashes
>back inside the condensor, BOOM.<<<<<
>
>Do you really think the condensor would create much shrapnel which could
>find its way back to the passenger compartment?  Seems to me that there's
>not much volume inside a condensor, I bet it would just split a seam or
>two.  Any DATA on this available?

There is no air in the condenser.. combustion needs fuel + oxidizer..
Explosion needs fuel + oxizider intimately mixed beforehand..

If you really want to worry, look at those "tire inflator/sealer" kits..
Many of them contain propane/butane for the propellant/fill gas..

Now you have air in the tire, mixed with fuel, under pressure..
this is a BOMB by defination.  There have been reports of service
stations nearly leveled when the attendant let the air/propane out,
and lit a cigarette.. those tires can have the explosive power of
a grenade or more... Nobody talks much about those..

Tire inflators are not a major economic threat to anyone..
But a recent Popular Mechanics ran an article titled "50,000 
Grenades on Wheels".. They weren't referring to tire inflators
either..(hint: OZ-12 refrigerant)..  Now go count all the ADvertizing
from the car companies in the magazine... and go figure out
what happens if said advertizing disapeared for a couple of years..
--ghg

From: ghg@cidmac.ecn.purdue.edu (George Goble)
Newsgroups: sci.engr.heat-vent-ac
Subject: Re: testing oil miscibility/oil return
Message-ID: <47jjop$imk@mozo.cc.purdue.edu>
Date: 6 Nov 1995 00:10:01 GMT
Organization: Purdue University Engineering Computer Network
Lines: 132

In article <47j7q8$50e@Twain.MO.NET> aschoen@mo.net (Andy Schoen) writes:
>In <47497t$9nv@mozo.cc.purdue.edu>, ghg@cidmac.ecn.purdue.edu (George
>Goble) writes:
[SNIP]
>>
>>Only advantage I can see in FRIGC is the raising the critical
>>temp of the refrigerant compared to 134a.. should help out in
>>"hot idle" (gridlock).. Their patent 5,425,890 claims the above
>>3 components..
>
>Thus the purpose for using R-124, a low pressure refrigerant,
>in their blend?

R-124 will certainly lower the critical temp of the blend.. It is
not really a "low pressure" refrigerant like R-11, but has a higher
BP than R-12.  Unless they form an azeotrope (very unlikely), three
components all with boiling  points higher than R-12, will never
get a boiling point to R-12, and will have low pressure problems
in an unmodified (ie. drop-in) system.


>>With all the bitching going on about flammability, even "weak"
>>flammability, what happens if a car sets parked with FRIGC, 
>>with a vapor leak, at an ambient temp of 15F..BP of 
>>of R-124 is 8.26F and R-134a is -15.07F and BP of R-600 (n-butane)
>>is 31.03F.  All the R-134a and R-124 will leak off, (15F ambient),
>>and R-600 (BP 31.03) will be left as liquid.. and could
>>concentrate to "3" flammability???  Wonder why they don't submit
>>to ASHRAE for an R-number and safety classif?  They would have
>>to do low temp leakdowns?
>
>Then you have folks promoting hydrocarbons as a substitute for
>R-12, e.g., OZ HC-12a....  Definitely a problem for service
>mechanics who like to smoke while they work.  :-)

It is possible to have small amounts of hydrocarbons in a blend
(for oil miscibility and oil return), and have the blend be
totally non flammable or very weakly flammable in worst case
scenarios (large vapor leak).. on the order 100X less  than
pure hydrocarbons like OZ-12, HC-12a, etc..  Outside of the safety
problem, hydrocarbons are excellent refrigerants.

Take a lit cigarette, and spray butane on it (from an unlit lighter),
and the cigarette will go out, most likely.  If you just took a long
drag on the cigarette, it will be hotter and problably ignite the
butane.  Cars carry around 100lbs or more gasoline.. and the public
and others get fanatic about 1lb of hydrocarbons in the A/C..
OZ-12 was on 50,000 cars and other things, before somebody wanted to
"make a point", and deliberately, after much trying, blew up cars
with it (letting it loose in the passenger cmpt, getting the air-fuel
mix right and igniting it).  In general propane/butane, etc, need
to be roughly 2-8% in air by volume to burn, out side that range, 
no fire. There were no reported safety problems with OZ-12
before that. Suddenly bunch of states banned it immediately.

There have been too many movies where the slightest accidents or
cars going off cliffs and exploding (sometimes in midair) to
inflame the public.  Take off the gas filler cap on a car, and
drop in a lit match.. what happens..

1) in the movies, the whole car blows up, along with the gas station.
2) in real life, the match goes out, or  a small flame forms at the 
   neck, which can easily be snuffed.

The movies often use waterbeds filled with gasoline in the trunk
and back seat, set off with a stick or two of dynamite..


Safety must be considered, but the flammability I think is
way overblown (due to the movies), and often not considered
in a scientific way

>>Jim Calm's June 1995 ARTI Refrigerant Dbase lists the above
>>formulation also (bet that is where you saw it?),
>
>No, actually, FRIGC notes this and other thermodynamic property
>details in their sales brochures.
>
>> however
>>there are rumors that FRIGC reformulated some.. changing
>>the R-600 to R-600a (n-butane to isobutane, BP 10.83).
>>I have no hard evidence of this though.. Using isobutane
>>would cause FRIGC to infringe on US patent 4,482,465 (Gray),
>>which has claims of "bracketing" (by boiling point) a
>>hydrocarbon with two nonflammable halocarbons.
>
>
>So, that's the trick of formulating ternary blends, eh?
>Does the patent cover all hydrocarbons whose BP falls
>within the BPs of the halocarbons one wants try to make
>a blend?  How about R-143a + R-134a + cyclopropane?
BP                    -53.23F  -15.07F    -27.2F

That would not infringe on Gray's patent.  Be pretty hard
to keep it non flammable though.. even with large amounts
of R-134a..  Pure R-134a is on the verge of burning in 100C
flammability tests now used by ASHRAE and UL.  R-143a
is "weakly" flammable and cyclopropane is highly flammable.
R-134a goes flammable at room temp, at 5PSIG above atmospheric.
   
Yep..about as broad as a patent on gravity.. what a pisser.


>>Someone might want to suggest to FRIGC (Intermagnetics?) to try
>>
>>R-600a/124/134a/22  4/28/40/28
>
>Well, that would certainly bring suction pressures up.  :-)
>
>I would suspect one design criteria used in the development of FR-12
>was not to use either CFC or HCFC components.  In that way, one can
>claim having a long term alternative, and not just a service replacement,
>even though R-22 will likely be around for quite some time.

HCFCs may be allowed for service until 2029  or such.. we will
all be dead or retired by then..


>How about using R-143a in place of R-22?

They already use a huge amount of R-124, chlorotetrafluoroethane, an HCFC..
I suggested R-22, since they already have HCFCs and cannot be vented.
and R-22 is cheap. R-143a, CF3-CH3, trifluoroethane, is weakly flammable,
flammability range around 7-19% in air by vol, slightly more flammable
than R-142b.



--ghg

Newsgroups: sci.energy
From: John De Armond
Subject: Re: NEWS & INFO: Ozone-Friendly Fridge Breakthrough (Detailed)
Message-ID: <08spsvp@dixie.com>
Date: Sun, 18 Oct 92 03:47:54 GMT

stead@skadi.CSS.GOV (Richard Stead) writes:

>In article <Greenpeace.16Oct1992.2210@naughty-peahen>,
>jym@mica.berkeley.edu (Greenpeace via Jym Dyer) writes:
>> OZONE-FRIENDLY FRIDGE BREAKTHROUGH AS ANTARCTIC OZONE HOLE WORSENS
>>
>> But the German company, DKK, has proved them wrong. Their new
>> fridge works on propane and butane as a coolant -- two simple

Jim, Jim, Jim... Tsk, Tsk.

Breakthrough? Recent?  As usual, the Econazis are a day late and a dollar
short.  As as usual with both Jim and Greenwar, they  get the facts
wrong.

Propane is a well known refrigerant and even has an R number.  (R-290 for
those who are interested.)  Propane is a pretty good direct substitute
for R-22.  It does not carry oil as well so some isobutane (note that,
Jim, Not butane) is added.  A non-azeotrop mix of 78% propane, 22% isobutane
is an exact replacement for R-12, the refrigerant used in some refrigerators
and car air conditioners.

George Goble at Purdue and myself (and probably others) have been
experimenting with this mix for at least 5 years.  This mix was proposed
as a substitute for R-12 in automotive use but the siren songs of the
safety nazis (more on that later) beat it down at every juncture on the
grounds of flammability.  We've collaborated on another non-flammable
direct drop-in R-12 replacement that has been on the market for almost 2
years and has recently received a US patent.  George presents a technical
article on this mix, known as "GHG R-12 Substitute", in the sample edition
of my magazine, available free for the asking.  If you get the sample
edition, you will also read about how the air conditioning service lobby,
in an unholy alliance with some environmental groups, is trying to
get the EPA to ban these substitutes (DuPont has one too) so as to force
the conversion to R-134a, said conversion for vehicles costing anywhere from
$800 to $2000.

>Ok, so it's ozone-friendly, but instead of releasing CFCs, it releases
>hydrocarbons.  There are several problems with this:
>1) hydrocarbons like propane and butane are greenhouse gases
>2) hydrocarbons, when mixed with nitrous oxides and sunlight, make ozone in
>   smog

What a simplistic riot.  Do a quick computation for me there, bud.  Figure
out how many farts it takes to equal the hydrocarbons contained in
the 8-12 ounces of refrigerant used in a refrigerator.  Sheez!

>3) hydrocarbons are very hazardous if they escape in your house.  Your fridge
>   develops a small leak, the motor comes on.  Boom!  Goodbye home and loved
>   ones.  And propane/butane is odorless - you won't know you have a leak.
>   They could try marking it with meythyl mercaptan, but how does that
>   affect the cooling properties of the mixture?

Oh bullshit.  Have you no concept of perspective?  A typical refrigerator
uses 8-12 ounces of refrigerant.  Do you have a feel for what a tiny
quantity that is?  Have you ever figured out how much butane propellant
is in a typical aerosol can?  Propellant is typically listed as a
percentage on the side of an aerosol can so it is easy enough to compute.
And do you quake in your shoes at the thought of having a can of butane
cigarette lighter fuel in your house?  The cans of butane I buy to
refuel my butane soldering iron contain 10 ounces in a paper-thin
steel can.  If you fear a few ounces of flammable refrigerant sealed
inside a thick hermetic system, you have to be terrified of aerosol
cans or lighter butane.  When was the last time you heard of a refrigerator
mysteriously springing a leak without provocation?  When was the
last time you heard of a aerosol can being punctured from being dropped
on a sharp object?  Or rusting through?  Or flat just starting to leak?

More to the direct point of the flammability issue.  The non-flammability
of CFC-type refrigeratants is a myth.  A CFC by itself is fairly hard to
ignite.  The refrigerant never exists in the absence of oil in a refrigeration
system.  A refrigerant mixed with oil mist, as always happens during a
leak of any consequence, is a whole 'nuther matter.  We've demonstrated,
and George made a video tape of, the equivalent flammability of
R-12 and oil vs propane and oil.  In the video, the burning jet from
the R-12 container is indistinguishable from that of the propane.
This video has surprised the experts in the field so surprise from the
layman is expected.

>This does not look like an ideal solution to the problem.  Maybe these problems
>aren't so bad, but I'll remain skeptical until this is really proven.

You're right here.  "Ideal" would be zero cost, zero environmental effect,
zero risk.  Not achievable except in the minds of some safety/econazis.
We can, however approximate "ideal" sufficient for refrigeration
purposes.

John

From: John De Armond
Newsgroups: sci.energy
Subject: Re: NEWS & INFO: Ozone-Friendly Fridge Breakthrough (Detailed)
Message-ID: <4=vpt+j@dixie.com>
Date: 19 Oct 92 08:49:42 GMT

stead@skadi.CSS.GOV (Richard Stead) writes:


>But that's the whole problem! If they never leaked, CFC's wouldn't be a problem
>either!  However, for the fridges that invariably get dumped in public areas,
>I don't have a good feeling about when the kids would come to fool around with
>one that happened to be propane cooled.

Ok, from the top.  How many 'friges have you ever seen dumped?  Three or
four?  A dozen?  Two dozen?  In my case I'd say perhaps a couple of
dozen.  Now how many million refrigerators are in use?  How many
do you suppose get fixed and/or recycled?  Hint:  Most of 'em.

Now, what difference in "bad feelings" would you have between kids
fooling around with propane refrigerant and those same kids fooling
around with a can of spray paint, a propane torch or a can of gas?
Particularly when this 'frige has been dumped out in some open
area?

>Yet we know that cooling systems leak -
>that's why so many people have to get their auto air-conditioners recharged
>every year or two.

Automobile A/C have nothing to do with this thread and are, of course,
completely different animals.  We're talking about hermetically
sealed refrigeration systems as installed in refrigerators, freezers and
so on.  Hermetic systems do NOT leak unless breached.  There is simply
no way for it to happen.  Example:  I have a 1929 GE Monitor Top
refrigerator.  Still running and still on the original charge.  Of
Sulfur Dioxide.

>I guess a thick hermetic system with lots of joints and
>O rings and moving parts just leaks easier than a simple spray can.

A car system is not hermetically sealed.

>Ok, I'm surprised.  I have a question - was the fridge on, or had it been
>off for awhile?  Running the fridge probably generates the mist, while an idle
>device may not?  I think both the safety of the running product and the stored
>(or dumped) product ought to be addressed.

Nope.  Doesn't matter.  Oil and freon are infinitely miscible and always
flow together.  The mist is formed when the pressure is suddenly reduced
as the mix escapes the system and the dissolved freon expands, breaking
the rest of the mix up into little droplets - an aerosol.  This is
EXACTLY how an aerosol can work.  Is it not obvious to you that
the contents of an aerosol can do not form a mist until sprayed?
The sloshing should give you a hint.

>Still, if it didn't ignite as
>a jet, I doubt that oil mist would stay suspended well enough to explode
>in a room.

Actually the oil mist stays suspended quite well because the boiling
effect makes such small particles.

>12 ounces of propane would occupy a kitchen of 12 feet x 12 feet
>x 8 feet at a partial pressure of 0.005 atmospheres.  That's a factor of
>4 too small to explode, but damn close for comfort.

I have no idea where you get your numbers but let me ask this.  Does
a safety factor of 4 really frighten you?  Do you have a concept of
what that means?

>> We can, however approximate "ideal" sufficient for refrigeration
>> purposes.

>I agree, but I'mm still not thoroughly convinced.  I'm not trying to be
>negative, just registering some honest scientific skepticism.

Sorry, Richard, but no, this is not scientific skepticism.  It is factless
fearmongoring.  If you really do fear things like this, your life
must be terrifying, what with all the other "dangerous" things like
electricity only a wrong move away.

John

Newsgroups: sci.energy
From: ghg@en.ecn.purdue.edu (George Goble)
Subject: Re: NEWS & INFO: Ozone-Friendly Fridge Breakthrough (Detailed)
Message-ID: <1992Oct19.095406.25747@en.ecn.purdue.edu>
Date: Mon, 19 Oct 92 09:54:06 GMT

In article <51359@seismo.CSS.GOV> stead@skadi.CSS.GOV (Richard Stead) writes:
>
>><John DeArmond writes>:
>> More to the direct point of the flammability issue.  The non-flammability
>> of CFC-type refrigeratants is a myth.  A CFC by itself is fairly hard to
>> ignite.  The refrigerant never exists in the absence of oil in a refrigeration
>> system.  A refrigerant mixed with oil mist, as always happens during a
>> leak of any consequence, is a whole 'nuther matter.  We've demonstrated,
>> and George made a video tape of, the equivalent flammability of
>> R-12 and oil vs propane and oil.  In the video, the burning jet from
>> the R-12 container is indistinguishable from that of the propane.
>> This video has surprised the experts in the field so surprise from the
>> layman is expected.
>
>Ok, I'm surprised.  I have a question - was the fridge on, or had it been
>off for awhile?  Running the fridge probably generates the mist, while an idle
>device may not?  I think both the safety of the running product and the stored
>(or dumped) product ought to be addressed.   Still, if it didn't ignite as
>a jet, I doubt that oil mist would stay suspended well enough to explode
>in a room.  12 ounces of propane would occupy a kitchen of 12 feet x 12 feet
>x 8 feet at a partial pressure of 0.005 atmospheres.  That's a factor of
>4 too small to explode, but damn close for comfort.

I fridge would only have 3-4oz most of propane/isobutane, not 12oz.
A car could have about 20 oz total.. About half the weight is needed of the
Freon-12 it replaces.  The flammability tests I did on R-12, were to
put 3lbs + 10% 525 viscosity mineral oil (typical charge for an auto
A/C) into a "dial-a-charge" measuring cylinder.  Opened 'er up and lit
it.. made a 12 ft jet of fire, similar to lighting WD-40 spray can.
This was back when it was still legal to vent CFCs.  If not ignited,
the "oil fog" hangs around for 10-15 mins sometimes.  It would be similar
to flour dust in a grain mill, etc.  I know refrigeration who caused
explosions (outside and rooftop units) when they lit up their torch
too quickly after blowing off the refrigerant charge.  It was the
oil mist which exploded.  Fridges use 150 viscosity oil instead of 525 as
cars do. 150 makes it even more "flammable".

WHen the Freon crunch hits in a year or so, and people forced with
a $1000-$1800 "retrofit" to R-134a, wonder how many will just sweat?
Wonder if anybody will go to their camping store and get a 6oz can
of isobutane fuel and go to the hardware store for 14oz of propane
and charge that into their car A/C?  That would be approx the correct
charge for a 40oz R-12 system and the mix would be 30% isobutane,
70% propane which might work.

--ghg

From: John De Armond
Newsgroups: sci.energy
Subject: Re: NEWS & INFO: Ozone-Friendly Fridge Breakthrough (Detailed)
Message-ID: <g=vp08h@dixie.com>
Date: 19 Oct 92 08:29:45 GMT

carl@SOL1.GPS.CALTECH.EDU (Carl J Lydick) writes:

>In article <08spsvp@dixie.com>, jgd@dixie.com (John De Armond) writes:
>>When was the last time you heard of a refrigerator
>>mysteriously springing a leak without provocation?

>Do you mean that much of the refrigerator service industry is a fraud?

I've sat here for several minutes trying to figure out how your question
related to my statement.  I can't figure a relationship and have to
assume you were simply making noise.  How you related fraud into this
discussion is beyond me?

I'll repeat the question.  When was the last time you heard of a refrigerator
springing a leak without provocation?  I'll tell you what my answer is.
Almost never.  In the 4 years I owned and operated a refrigeration
service company, I could count on one hand the times I found a hermetic
system that needed charging.  I'd bet those were deficient from
the factory.  The reason is simple.  The system, as its name indicates,
is hermetically sealed.  Until the owner provokes a leak, typically
with a knife or ice pick, there is no place for the freon to leak from.

John

From: John De Armond
Newsgroups: sci.energy
Subject: Re: NEWS & INFO: Ozone-Friendly Fridge Breakthrough (Detailed)
Message-ID: <3nvp+g_@dixie.com>
Date: 19 Oct 92 16:24:58 GMT

gary@ke4zv.uucp (Gary Coffman) writes:


>BTW propane/isobutane mixes used
>as refrigerants are nothing new. They, along with ammonia, were widely
>used before CFCs were developed. Since ammonia is toxic, and propane
>flamable, CFCs were embraced by the industry as a *safe* alternative
>to these chemicals. It's really no big deal to go back to these older
>methods, but you have to assume the risks they pose that caused them
>to be replaced in the first place. There is no free lunch.

Ammonia, Sulfur Dioxide and Methyl Chloride were the predominant refrigerants
used before CFCs according to my 1940 Coyne Refrigeration Handbook. Back
then the hazards were real and severe.  Flooded evaporators were the norm,
as were open shaft (non-hermetic) compressors.  A household system such as my
GE Monitor Top might contain literally gallons of refrigerant.

Several things must be known in order to assess the risk.  In most
refrigerators up to the late 60s, the evaporator was either a structural
component or was exposed on the surface of the interior.  In my MonitorTop,
the evaporator assembly is a massive cast aluminum assembly.  It forms
the "freezer" part of the refrigerator.  Later designs pressed the evaporator
coils into sheets of metal that formed either the freezer or lined the
walls of same.  None were frost-free.  The greatest risk, and the repairman's
favorite person, was the housewife wielding an ice pick while defrosting.
Even the old MonitorTop suffered from that risk.  My handbook outlines in
some detail the art of aluminum soldering, an art perfected decades before
these shysters at flea markets selling miracle rods came along.

Let's compare that to today's refrigerator.  The refrigerant system is
totally hermetically sealed. Physical damage and a very rare compressor
lead penetration burnthrough are the only real threats to the system's
integrety.  The evaporator is typically buried in the bottom or the back
and cold air is circulated by fan.  There is no defrosting and indeed,
the owner could not do so without disassembling the unit.  The amount of
refrigerant involved might mostly fill a coffee cup.  Given these design
features, I'd have no problem at all even with sulfur dioxide as the
refrigerant.  I wouldn't even give a second thought to something
as innocuous as propane/isobutane.

I wonder how many people would recoil in horror at a propane refrigerant
routinely use a gas stove in their kitchen.  A device lacking any
safety cutoff and connected to an unlimited supply of gas.  Hmmm.

John