A/C converson from Freon to R134- Necessary?
Gregory P Dubois-Felsmann
<nrl...@ccsalpha1.nrl.navy.mil> wrote:
>Manly Matt Schulman (schu...@nova.gmi.edu) writes:
>> R12 is no longer being produced, by federal law.
>> ....[snip]....
>> Note that *large* containers (>20 lb) are still legally available to
>> unlicensed consumers....
>If I recall correctly, the production ban is to take effect November 1st.
>That is also the day unlicensed consumers will no longer be able to purchase
>R12 in any size container. Just to pick another nit here, the restriction
>until then is that only licensed technicians can buy R12 in containers of
>LESS THAN 20 lb capacity. Other persons can buy R12 in 20 lb (in spite of
>what some ignorant salespersons say) and larger containers. Also, don't forget
>that R134 will be banned a few years down the road.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I don't believe this is true. Can you provide a reference?
The primary component of R-134a, HFC-134a, is a hydrofluorocarbon,
containing no chlorine. It is not an ozone depleter to any significant
extent and is not controlled under the international agreement on ozone
depleting substances, the Montreal Protocol. There is very general
agreement on this and this situation is most unlikely to change.
HFC-134a is a greenhouse gas, and may possibly be controlled as such
at some point in the future. However, it should be noted that the US
and most of the European Union are finding it difficult to adopt
regulations or other control measures even to freeze emissions of
greenhouse gases by 2000 or reduce them by 20% by 2010, let alone ban
them. It would be very surprising, therefore, if HFC-134a were to be
"banned" in "a few years".
Various industries world-wide are proceeding under the assumption that
HFCs, including -134a, will be available for a long time to come.
Policy-makers are acutely aware of this.
If the claim of an imminent ban on R-134a is not correct, it would be
very regrettable if the readers of rec.autos.tech, who are currently
faced with sometimes difficult and expensive choices related to the
R-12 phaseout, were left with the impression that they were not going
to be able to enjoy the fruits of their conversion (or new car)
investment for very long. In the spirit of Usenet, the previous
poster should be given the benefit of the doubt, but I would at least
urge readers not to act on the claim or pass it on as correct until
we've clarified the point.
It is possible that there may be some confusion here between *HFCs*
(such as -134a) and *HCFCs* (such as HCFC/R-22, used in domestic air
conditioning and other applications). HCFCs (hydrochlorofluoro-
carbons) do contain chlorine and *are* ozone-depleting, though less so
than CFCs. International policy regards them as "transitional
substances" to be used as substitutes for CFCs until better and/or
non-ozone-depleting alternatives are available, and they *are*
scheduled for phase-out (by 2020, with a tiny amount permitted until
2030) under the Montreal Protocol. The European Union is likely to
decide in December to phase out HCFCs by 2015. There are other
restrictions on HCFC use in various countries.
Some of the R-12 substitutes that have been considered for mobile A/C
(but *not* R-134a) do contain HCFCs and would therefore not be
available for the indefinite future.
--
Gregory
Bruce Hamilton
>In article <9410241...@ccsalpha1.nrl.navy.mil>,
> <nrl...@ccsalpha1.nrl.navy.mil> wrote:
>>what some ignorant salespersons say) and larger containers. Also, don't forget
>>that R134 will be banned a few years down the road.
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>I don't believe this is true. Can you provide a reference?
This has been the aim of Greenpeace for the last few years,
and they have started to lobby intensively. Though, in this case
I think your (deleted) suggestion that the writer may be confusing
HCFC-22 and HFC-134a is most likely.
Greenpeace appear to be using the provisions which permit the use
of chemicals with a GWP only untill an alternative with a better
GWP is available, in which case the HFC should be replaced.
However it is unlikely to happen in the near future, despite the
GP lobbying, unless dramatic new evidence on global warming
appears. Approximately 90% of new vehicle AC systems are
now HFC134a, and no alternatives are compellingly superior
in all the necessary requirements, although it is possible
new systems auto A/C sytems may move to flammable HC
mixtures - with the requirement that leak rates are reduced.
It is very likely that most retrofit systems will be HFC-134a
until the vehicle is eventually scrapped.
From "Global Warming Implications of replacing CFCs"
Steven K Fischer, Phillip D Fairchild, Patrick J Hughes.
ASHRAE Journal April 1992 p14-19 Table 1
Global Warming Potentials of Traces gases relative to CO2
Integration Time Horizon 20yrs: 100yrs: 500yrs.
( that's the effect of 1 kg of substance compared to 1 kg of CO2,
both released at the same time. The number is the number of
kgs of CO2 - thus at 100 years the CFC-12 will still have the
same global warming effect as 4500 kgs of CO2 released at year 0 )
CO2: 1: 1: 1:
methane: 63: 21: 9:
Nitrous Oxide: 270: 290: 190:
CFC-11: 4500: 3500: 1500: ( old blowing agent in fridge insulation )
CFC-12: 7100: 7300: 4500: ( old Domestic fridge, old Auto A/C )
HCFC-22: 4100: 1500: 510 ( old Domestic A/C )
HCFC-141b: 1500: 440: 150 ( new blowing agent in fridge insulation
- n-pentane, cyclopentane are also popular as blowing agents )
HFC-134a: 3200: 1200:420 ( new Auto A/C )
HFC-152a: 510: 140: 47 ( potential A/C, but flammable )
( I think the above are the 1990 IPCC GWP numbers )
>HFC-134a is a greenhouse gas, and may possibly be controlled as such
>at some point in the future. However, it should be noted that the US
>and most of the European Union are finding it difficult to adopt
>regulations or other control measures even to freeze emissions of
>greenhouse gases by 2000 or reduce them by 20% by 2010, let alone ban
>them. It would be very surprising, therefore, if HFC-134a were to be
>"banned" in "a few years".
Given the GWPs above, I'd guess that if a global warming problem
existed then HFC-134a could well be replaced in new car systems,
but it is likely to remain as the refrigerant of choice for retrofits for
the next couple of decades.
Many cynical commentators have already pointed out that the US Govt
asked Du Pont to produce additional cfcs, even though Du Pont were
prepared to stop. It has been estimated that the govt will collect an
additional $400million in taxes from this ( higher taxed ) product.
It has been suggested by GreenPeace that both HCFC and HFCs should be taxed
similarly once lower GWP alternatives are found. Some politicians may
find the revenue attractive, especially as the planned ramping up of taxes on
the HCFCs will ultimately diminish as a revenue source as they are phased
out. Politicians appear to have longer vision when they consider possible
revenue sources :-(.
>If the claim of an imminent ban on R-134a is not correct, it would be
>very regrettable if the readers of rec.autos.tech, who are currently
>faced with sometimes difficult and expensive choices related to the
>R-12 phaseout, were left with the impression that they were not going
>to be able to enjoy the fruits of their conversion (or new car)
>investment for very long. In the spirit of Usenet, the previous
>poster should be given the benefit of the doubt, but I would at least
>urge readers not to act on the claim or pass it on as correct until
>we've clarified the point.
I agree, I think that HFC-134a is the current best option for both new
and retrofit systems ( with regard to cost, safety, and performance.
and yes, I'm aware of nC3/iC4/nC4 blends )
Automakers have spent significant sums developing retrofit kits for this
material, and as I noted above over 90% of new vehicles use it. It is unlikely
to be "banned" in the imminent future, but it is likely to come under some
sort of regulation as pressure increases on govts to honor their Global
Warming reduction committments. However potential users should
not be concerned, the wholesale adoption of this "safe" alternative by the
auto manufacturers will help ensure a supply. ( safe=non-flammable -
even thought HFC-152a is more difficult to ignite that the nC3/iC4/nC4blends,
the automakers refused to introduce it because of potential lawsuits )
Bruce Hamilton
Gregory P Dubois-Felsmann
Bruce Hamilton <B.Ham...@irl.cri.nz> wrote:
>In article <1994Oct28....@inca.comlab.ox.ac.uk>
>dub...@sable.ox.ac.uk (Gregory P Dubois-Felsmann) writes:
>>In article <9410241...@ccsalpha1.nrl.navy.mil>,
>> <nrl...@ccsalpha1.nrl.navy.mil> wrote:
>>>what some ignorant salespersons say) and larger containers. Also, don't forget
>>>that R134 will be banned a few years down the road.
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>>I don't believe this is true. Can you provide a reference?
[Bruce Hamilton and I discuss R-134a as a substitute for R-12 in mobile
air conditioning, and conclude that it is likely to be available for long
enough that any eventual restrictions on its use probably needn't be of
concern to people considering retrofitting their existing R-12-using
vehicles.]
[Bruce Hamilton concludes:]
>I agree, I think that HFC-134a is the current best option for both new
>and retrofit systems ( with regard to cost, safety, and performance.
>and yes, I'm aware of nC3/iC4/nC4 blends )
>
>Automakers have spent significant sums developing retrofit kits for this
>material, and as I noted above over 90% of new vehicles use it. It is unlikely
>to be "banned" in the imminent future, but it is likely to come under some
>sort of regulation as pressure increases on govts to honor their Global
>Warming reduction committments. However potential users should
>not be concerned, the wholesale adoption of this "safe" alternative by the
>auto manufacturers will help ensure a supply.
Here is what the US EPA had to say about R-134a in this application in
its Notice of Proposed Rulemaking on alternatives to ozone-depleting
substances dated 26 September 1994:
(a) HFC-134a. HFC-134a is acceptable as a substitute for CFC-12 in
retrofitted and new motor vehicle air conditioners, subject to the use
conditions applicable to motor vehicle air conditioning described
above. HFC-134a does not contribute to ozone depletion. HFC-134a's GWP
and atmospheric lifetime are close to those of other alternatives which
have been determined to be acceptable for this end-use. However, HFC-
134a's contribution to global warming could be significant in leaky
end-uses such as motor vehicle air conditioning systems (MVACS). EPA
has determined that the use of HFC-134a in these applications is
acceptable because industry continues to develop technology to limit
emissions. In addition, the number of available substitutes for use in
MVACS is currently limited. HFC-134a is not flammable and its toxicity
is low. While HFC-134a is compatible with most existing refrigeration
and air conditioning equipment parts, it is not compatible with the
mineral oils currently used in such systems. An appropriate ester-
based, polyalkylene glycol-based, or other type of lubricant should be
used. Consult the original equipment manufacturer or the retrofit kit
manufacturer for further information.
--
Gregory
George Goble
>In article <3905ic$5...@mozo.cc.purdue.edu> g...@freedom.ecn.purdue.edu (George Goble) writes:
>
>>In article <B.Hamilton....@irl.cri.nz> B.Ham...@irl.cri.nz (Bruce Hamilton) writes:
>.....
>>>It is very likely that most retrofit systems will be HFC-134a
>>>until the vehicle is eventually scrapped.
>
>
>Any shonky ( =dubious quality ) retrofit adversely affects operational
>life - not just HFC-134a retrofits. That's why Ford has been very
>careful. From Car & Driver? July 1994. "The Last, fretful Days of R-12"
If FORD had given a damn about A/C systems at all, they would have
never introduced the "spring-lock" connections in their A/C systems.
Those have been nothing but trouble for years... go ask any independent
service shop about those designed to be leaky connectors. While you are
at it, ask the service shop for a list of their failure-prone compressor
model numbers. Any why does the service shop's cost for a FORD drier
come to around $120 (plain 'ole XH5 R-12 drier).. The shop has to mark
it up again. GM, Chysler, and independent driers are often $15-$25
shop cost. Sounds like Ford just cares about maximizing serivice
income.
[... deleted ..]
Fact of life:
Many major publications RELY on heavy advertising from the auto industry.
Like Millions of $$$ in advertising.
One cannot cut off the hand which feeds them.
These publications CANNOT print things which tick off the auto
industry (i.e. good things about blends, bad things about R-134a, etc)..
If they did that, all the big three + Japan would yank ALL their
adds.. for many months, causing the publication economic ruin.
I know of several instances where popular publications have "prepared"
stories/interviews/photo sessions, for alternative refrigerants, etc,
and have scuttled them when the advertising dept found out.
One mag called one model of some Japanese car a "lemon" once, and
lost over a year's worth of advertising from that one company.
>Still, confusion will most likely reign, because customers will look for cheap
>solutions, and some repairmen will promise anything. There'll be short-cut
>kits and magic potions. An example is a refrigerant that's a mixture of
>propane and butane. "You don't have to change anything!" It'll cool.
>Lubrication is iffy. And if a leak gets sparked in the engine bay, Kaboom!"
Lubrication is VERY GOOD for hydrocarbons in mineral oil. There is an
upcoming EPA approved R-12 substitute for cars, which is just R-134a
with a little N-butane (and R-124 to mitigate flammability) thrown in
to cause it to work in mineral oil. Performance is unknown with this
blend, since it is not yet on the market (FRIGC). R-134a boiling point is
-15F and R-12's is -21F, so R-134a dropped in to a R-12 system is going
to have lower capacity (not counting the oil problems). Adding N-butane
(B.P. 31F) and R-124 (B.P 12F) is going to make the capacity still lower,
but it will keep the head pressure down and the critical temp up.
They could have made a better refrigerant by using isobutane (B.P. 10F)
instead of N-butane, but that would have infringed on US patent
4,482,465 (Gray/Phillips-66).
There is some flammability risk for running pure hydrocarbons
(propane/butane, etc) in automotive A/C.. but it is pretty small.
OZ-12 (propane/isobutane) was installed in 50,000 cars with no
fire/safety problems reported.. until somebody "rigged" a controlled
demo, where 3 cans of it were released (took several tries) in a sealed
car passenger compartment, and recirulated until the correct fuel/air
mix was obtained.. and BOOM.. it did blow up. Film at 11.. went to
CNN, etc.. which pretty much got it banned. Using the fear of fire
in a non scientific manner to fear-monger the public.. Remember the
Hindenburg, the Pinto, The side mounted Pickup truck gas tanks, etc..
(remember the rocket engine ignitors?? on the truck blowing up?)
The A/C only holds 1.5lbs or so of propane/isobutane. The gas tank
holds over 100lbs of gasoline. Oil, brake fluid, transmission fluid,
power steering fluid, are all EXTREMELY FLAMMABLE/EXPLOSIVE when they
drip on hot enging/exhaust components. Hydrocarbons have to be at a fuel/air
ratio of roughly between 2% - 8% by volume in air in order to ignite.
In a hose break/leak, propane/butane dissipate rapidly, gasoline
hangs around, fuming, waiting for an ignition source.
R-12 systems contain approx 10-15% by volume of mineral oil, which
is dissolved in the refrigerant. A line rupture creates in "oil fog"
which can be quite explosive. A jet of R-12/oil mist leaking can be
ignited (I have a pix) and does sustain fire (looked like a flame-thrower).
That is why "those in charge" are VERY CAREFUL to specify flammability
specs WITHOUT the oil present, rather that what is really found in
a car A/C. When you include the compressor oil, all the refrigerants burn.
Also, many common "tire inflator/sealer kits" use propane
and butane, and it is mixed with AIR UNDER PRESSURE in a TIRE.. and
this IS A BOMB by definition. How come nobody raises much ruckus over
tire inflators, R-12 and oil burning, etc. Those things do not have
the power to prevent the sale of millions of "extra" new cars like the
alternative refrigerants do (when the R-12 is gone). R-134a does become
flammable at just above atmospheric pressure (5 PSI). There have been
reports of R-134a explosions in refrigerant lines/compressors.. Workers
unsoldering lines (had air/R-134a in them), after letting out the
refrigerant, built up a small positive pressure, or the burning of
the oil at the joint raised the local pressure above 5 PSI, and blam.
Go figure for yourself.
>>Even some stationary equipment mfgrs are reporting problems with NEW
>>R-134a equipment (refrigerators, etc). Some equipment has been
>>recalled. We have even heard of a company suspending production
>>on new refrigerators until R-134a/oil problems can be worked out.
>
>Well, undoubtably true, but that company has to address the problem
> quickly or lose the market. York, Tecumseh and Sanden have R134a
>compressors in the market here, and several systems manufacturers
>supply the OEM installations on new cars.
How many car makers'
production lines/service shops will take the care and scrupulous
techniques that a scientific lab does when building or servicing
R-134a systems or retrofits. 3 years ago, I visited a dozen or so
air shops, using recycled R-12.. Every single one of them had "wet"
moisture indicators on their recyclers.. All but one of their vacuum
pumps failed to reach a micron vacuum (< 1000 microns is needed for
moisture removal before charging). Asked them when they changed
driers in their recyclers, and they said "what driers" and on the
pumps, "what pump oil", we use ATF transmission fluid for that!
What happens when production lines stop for awhile with "open"
A/C systems (drier soaking up water).. and shoddy service techniques
are applied to oils which are 10X or 100X more hydroscopic than
5GS?? go figure...
>
>>Under the hood, radiator temps often hit 220F or so.. Since the
>>condenser is bolted next to the radiator, it sometimes sees these
>>temps also (I have measured condenser temps on an an instrumented
>>vehicle). The "critical" temp of a gas, is the temp at above which
>Yup, these, and many more, are discussed in the above articles
>- along with the techniques to eliminate/minimise the problems.
>There have been plenty of successful retrofits on a wide
>range of vehicles. I didn't say there wouldn't be problem,
>but it seems the solutions are arriving thick and fast.
Has anybody wondered if massive retrofit failures are the "solution"??
Gets lots of service business.. then gets the service (3rd party)
out of business when they fail after 6mo-year.. "You should have
gone to the dealer all along..." Now with unservicable A/C, consumers,
say "screw it", and trade up for a "new car".. 130-150 million R-12
cars out there.. go figure...
>
>>R-134a needs a much larger condenser due to this, and it located
>>away from the radiator (may not be possible), and beefed up
>>radiator fans to suck in more cool air than for R-12. Retrofitted
>>R-12 systems are not likely to have large condensers/more air
>>flow.. so they will have very poor low speed/stopped performance.
>
>This is discussed at length in the Automotive Engineer article,
>noting that the operating pressure of correctly retrofitted systems
>is about 15% higher. They note that parallel flow condensors can
>be used where space is a problem, and that Ford plans modications
>to the electric fans for front-drive cars. The cost-effectiveness of
>the upgrade depends on the price of such aftermarket modifications
>and the auto manufacturers recognise this. Condenser effectiveness
>depends on airflow. These people aren't bunnies, their retrofits are
>likely to meet their target specifications for performance and price.
Lots of room needed for beefing up things, no space in many compact
cars.. this means dozens of "custom" condensers need to be designed,
with custom fans, baffles, etc...a real integration problem. Plus
then you have the chloride/moisture problems to deal with.. How many
are going to do a "correct" retrofit, where everything which touches
refrigerant is replaced? About $1500 or more incl labor.. That one
solves the residual chloride problems. Esters don't have as good of
lubricity as do the Minerals or PAGs..
>
>>Zeotropic blends (R-400 series refrigerants) can extend the
>>active phase change area of the condenser, thereby increasing
>>performance of the system provided operating conditions are met.
>
>True. But each retrofit alternative has its own problems, and currently
>the best thing going for R134a is the widespread utilization of it as
>OEM systems in new cars. I'm not trying to imply anything about your
>product, but for many reasons I'd prefer to see flammable refrigerants
(R-406A is not participating in the automotive sector)
>initially introduced in carefully evaluated OEM systems on new vehicles.
>
Europe is using hydrocarbons now in new mfgr.. The main problem with
alternatives, is the damage to the pocketbooks of Detroit.
Why is Australia using MP52 (R-401C) for retrofits instead of R-134a?
It runs in Alkylbenzene oil which is very similar to Mineral oil
so it has no problems with PAG/Ester oil breakdowns. No major auto
companies there or too few people to boycott MP52 there??
> Bruce Hamilton
--ghg
George Goble
>In article <B.Hamilton....@irl.cri.nz> you write:
>>In article <3905ic$5...@mozo.cc.purdue.edu> g...@freedom.ecn.purdue.edu (George Goble) writes:
>>
>>>In article <B.Hamilton....@irl.cri.nz> B.Ham...@irl.cri.nz (Bruce Hamilton) writes:
>>.....
>>propane and butane. "You don't have to change anything!" It'll cool.
>>Lubrication is iffy. And if a leak gets sparked in the engine bay, Kaboom!"
Remember the old pre-computer cars with carbs? How many times
did people inadvertantly "flood" them by pumping the throttle
too much? Remember you can to "floor" 'em and keep cranking
until the over rich mixture was sucked into the engine and it
leaned down until the upper flame limit was reached and the
car started? Remember the smell of gasoline fumes in the
passenger compartment? How much gasoline fumes do you think
where under the hood then? Starter solenoid/commuter sparking..
How many "flooded" cars actually blew up? Must not have been
very many or we would have had a national outcry. Why is propane/
butane refrigerant gonna be any worse if it is leaking. To even
approach flamability limits, the leak has to be pretty severe
(few hours or less)..
--ghg
Bruce Hamilton
In article <3968vj$4...@mozo.cc.purdue.edu>
g...@freedom.ecn.purdue.edu (George Goble) writes:
>In article <B.Hamilton....@irl.cri.nz> you write:
>> g...@freedom.ecn.purdue.edu (George Goble) writes:
>>> B.Ham...@irl.cri.nz (Bruce Hamilton) writes:
....
>>Any shonky ( =dubious quality ) retrofit adversely affects operational
>>life - not just HFC-134a retrofits. That's why Ford has been very
>>careful. From Car & Driver? July 1994. "The Last, fretful Days of R-12"
>If FORD had given a damn about A/C systems at all, they would have
>never introduced the "spring-lock" connections in their A/C systems.
It's a pity you chose to delete the following, I've no wish to become
involved in anti-marque crusades. I wrote :-
>>Ford has set high standards [ don't shoot me - I'm only quoting the
>>article :-) ] for its factory kits , "no loss of performance, or durability,
>>or driveability,"
>Fact of life:
>Many major publications RELY on heavy advertising from the auto industry.
>Like Millions of $$$ in advertising.
>One cannot cut off the hand which feeds them.
>These publications CANNOT print things which tick off the auto
>industry (i.e. good things about blends, bad things about R-134a, etc)..
>If they did that, all the big three + Japan would yank ALL their
>adds.. for many months, causing the publication economic ruin.
One problem with this conspiracy theory is that I've previously quoted
similar articles from non-automotive journals, including the "Looming
Ban on Production of CFCs, Halons Spurs Switch to Substitutes" from
Chemical & Enginnering News Nov 15 1993 p12-18. "Ozone-Friendly
Cooling" Popular Science July 1990 p57-63. "Replacing CFCs:The search
for alternatives" Ambio Oct 1990 p329-333. HFC producers could also
conspire
Besides, GreenPeace has been strongly lobbying for the banning of
R134a and its replacement by hydrocarbons, the lobbying is not all
one-sided...
>>Still, confusion will most likely reign, because customers will look for cheap
>>solutions, and some repairmen will promise anything. There'll be short-cut
>>kits and magic potions. An example is a refrigerant that's a mixture of
>>propane and butane. "You don't have to change anything!" It'll cool.
>>Lubrication is iffy. And if a leak gets sparked in the engine bay, Kaboom!"
...
>There is some flammability risk for running pure hydrocarbons
>(propane/butane, etc) in automotive A/C.. but it is pretty small.
>OZ-12 (propane/isobutane) was installed in 50,000 cars with no
>fire/safety problems reported.. until somebody "rigged" a controlled
>demo, where 3 cans of it were released (took several tries) in a sealed
>car passenger compartment, and recirulated until the correct fuel/air
>mix was obtained.. and BOOM.. it did blow up. Film at 11.. went to
>CNN, etc.. which pretty much got it banned. Using the fear of fire
>in a non scientific manner to fear-monger the public.. Remember the
>Hindenburg, the Pinto, The side mounted Pickup truck gas tanks, etc..
>(remember the rocket engine ignitors?? on the truck blowing up?)
No, the flames weren't visible down here. :-)
According to Automotive News. Nov 8 1993 p1&45.
"Late this summer, International Association Arson Investigators
conducted tests with as liitle as 5.5 ounces of the OZ-12 material
introduced into vehicle interior. "When the ignition source was
activated, the result was an explosion that blew the windows
out of the car," said a source with the State of Florida.....
The air conditioner's evaporator, located in the firewall, would
provide a possibleentry point for the material into a vehicle cabin."
I've previously said that I accepted these trials probably weren't
valid, but you continue to berate me...
>The A/C only holds 1.5lbs or so of propane/isobutane. The gas tank
>holds over 100lbs of gasoline.
We've been down this path before, my concern is with retrofits. The
air conditioning system is designed and incorporated into the vehicle
using non-flammable refrigerants ( we'll discuss the flammability later )
that leak at around 0.15-0.25 pounds annually ( I like these quaint units :-))
>Oil, brake fluid, transmission fluid,
>power steering fluid, are all EXTREMELY FLAMMABLE/EXPLOSIVE when they
>drip on hot enging/exhaust components. Hydrocarbons have to be at a fuel/air
>ratio of roughly between 2% - 8% by volume in air in order to ignite.
All of which are located appropriately by the engineers designing the vehicle,
taking due notice of the physical properties of the internal fluid. If they
get it wrong and locate the gas tank where it can be hit, or make fuel
pump diaphragms that expand/shrink due to gasoline aromatic/olefin
concentration changes - resulting in major sprays of pressurised gasoline
over the exhaust and alternator, they soon rectify it. In this case a
non-flammable refrigerant is being replaced by a flammable one
in an existing system.
>In a hose break/leak, propane/butane dissipate rapidly, gasoline
>hangs around, fuming, waiting for an ignition source.
>R-12 systems contain approx 10-15% by volume of mineral oil, which
>is dissolved in the refrigerant. A line rupture creates in "oil fog"
>which can be quite explosive. A jet of R-12/oil mist leaking can be
>ignited (I have a pix) and does sustain fire (looked like a flame-thrower).
True, I didn't say it couldn't - however I don't have statistics on the
number of R-12/oil fires, However I suspect the number is fairly low.
Burning R-12 also produces toxic fumes, but let's put it this way -
how many R-12 service people have you seen immolated using the
flame copper halide, or heated Pt electronic leak detectors to test
R12 systems. ( and yes, I'm aware the Cu flame test isn't appropriate
for R-134a ). You must be aware that one of the major opponents to
OZ-12 was the Mobile Air Conditioning Society - " The use of flammable
...refrigerants poses safety concerns to the technicians servicing
mobile air-conditioning systems" states an October 1993 bulletin from
MACS. They're not bunny Usenet posters like I apparently am.
>That is why "those in charge" are VERY CAREFUL to specify flammability
>specs WITHOUT the oil present, rather that what is really found in
>a car A/C. When you include the compressor oil, all the refrigerants burn.
You know as well as I, that the Test Method specified by the US Department
of Transportation as the procedure for determining whether a compressed
gas is classified as flammable or nonflammable is ASTM-E361, and has been
for a very long time. If you want some data, refer " Flammability of
alternative refrigerants" Robert G Richard, Ian R Shankland. ASHRAE
Journal April 1992 p20-24. Table 4. Refrigerant Flammability
Material, Flammable Range, temperature, Ignitionsource
Propane, 2.1-9.6, RT, Match
Butane, 1.5-10.1, RT, Match
isoButane, 1.7-9.7, RT, Match
R-134a, none, RT, Match.
( Yes they do use the electrically-activated match ignition source
specified in ASHRAE Standard 34-1989 ( because many of the
halocarbons are difficult to ignite - maybe the OZ-12 Arson
Investigators above didn't :-) ).
> R-134a does become
>flammable at just above atmospheric pressure (5 PSI). There have been
>reports of R-134a explosions in refrigerant lines/compressors.. Workers
>unsoldering lines (had air/R-134a in them), after letting out the
>refrigerant, built up a small positive pressure, or the burning of
>the oil at the joint raised the local pressure above 5 PSI, and blam.
>Go figure for yourself.
Refer above, the service technicians seem to prefer R-134a for
retrofits rather than HCs, so would I. You may choose otherwise...
>How many car makers'
>production lines/service shops will take the care and scrupulous
>techniques that a scientific lab does when building or servicing
>R-134a systems or retrofits.
Several makers support R-134a ( and I've previously posted on the
data on the 2 years/million mile ICI trials - which also found none of the
vehicles' owners took ICI up on their offer of a free retro-retrofit back
to R-12 at the end of the trials). Volvo's low-priced scheme ( $45 parts, $21
R-134a, estimated $200 for labor ) was intended to encourage owners to
take the environmentally beneficial option,
> 3 years ago, I visited a dozen or so
>air shops, using recycled R-12.. Every single one of them had "wet"
>moisture indicators on their recyclers.. All but one of their vacuum
>pumps failed to reach a micron vacuum (< 1000 microns is needed for
>moisture removal before charging). Asked them when they changed
>driers in their recyclers, and they said "what driers" and on the
>pumps, "what pump oil", we use ATF transmission fluid for that!
Well, if the US auto A/C service industry can't get its act together,
maybe the US consumer would be better served by an Asian
service chain. We both know the above are not acceptable
practices for CFCs, let alone alternatives. MACS also expressed
concern about "low down and dirty pricing" of retrofitting. As
MACS represents the servicing industry, it shouldn't be concerned
if shonky operators bite the dust.
>What happens when production lines stop for awhile with "open"
>A/C systems (drier soaking up water).. and shoddy service techniques
>are applied to oils which are 10X or 100X more hydroscopic than
>5GS?? go figure...
Come on, these refrigerants probably still aren't as hydroscopic as
glycol brake fluids, and the boiling point reduction caused by water
is far more safety critical ( sudden, total loss of brakes ) - if necessary
Toyota etc can show the US industry hoew they currently do it.
We both know production lines can operate to produce low moisture
systems.
...
>Has anybody wondered if massive retrofit failures are the "solution"??
>Gets lots of service business.. then gets the service (3rd party)
>out of business when they fail after 6mo-year.. "You should have
>gone to the dealer all along..." Now with unservicable A/C, consumers,
>say "screw it", and trade up for a "new car".. 130-150 million R-12
>cars out there.. go figure...
Conspiracy theory - bad news travels fast. Long term players will
provide long term solutions. I think I initially quoted from the July
1994 ( Car & Driver? ) article by Patrick Bedard " As carmakers do
more testing, retrofits seem less of a nightmare..."
>> These people aren't bunnies, their retrofits are
>>likely to meet their target specifications for performance and price.
>Lots of room needed for beefing up things, no space in many compact
>cars.. this means dozens of "custom" condensers need to be designed,
>with custom fans, baffles, etc...a real integration problem. Plus
>then you have the chloride/moisture problems to deal with.. How many
>are going to do a "correct" retrofit, where everything which touches
>refrigerant is replaced? About $1500 or more incl labor.. That one
>solves the residual chloride problems. Esters don't have as good of
>lubricity as do the Minerals or PAGs..
We've been down this path ealier this year. the chloride/moisture
problems can be overcome with appropriate selection of formulation
and operational procedures. A "correct" retrofit doesn't involve a
complete replacement. Refer above for the Volvo, ICI examples;
and I'll repeat a quote from the above C&EN article " In 1991, the auto
industry estimated retrofitting costs would range from $200-$1200 per car,
depending on the make, model, and year.... But after a few years experience
withretrofitted vehicles, it appears the high end of the cost range may
have ben overestimated".
...
>Europe is using hydrocarbons now in new mfgr.. The main problem with
>alternatives, is the damage to the pocketbooks of Detroit.
I'm sure Detroit will listen carefully, especially if you offer complete
indemmification for all A/C fire claims. Of course they might want
to know that you have the $ to back it up. I've consistently said
that I have no problem with HC designed/tested OEM systems.
>Why is Australia using MP52 (R-401C) for retrofits instead of R-134a?
Pardon?. As far as I know, R-134a is the typical retrofit refrigerant.
Their major automotive service organisation (IAME) is offering
courses on "CFC Recovery Authorisation" "Air Conditioning
Servicing" and "R-134a Retrofitting" . No mention of
R-401c. The OEMs are using R-134a. You can Fax the IAME
at +0061 2 713 2671 ( phone +0061 2 713 4711 ) for more details.
I can't say for sure they aren't using R-401c. But they also
had the R-134a article I quoted in my previous post, I haven't
seen any references to R-401c - but then it's not my field.
Bruce Hamilton
George Goble
> Well, it seems a raw nerve was accidentally exposed....
>
Lots of Raw nerves. Esp on the Ford Driers and Spring-Lock connectors..
> >Fact of life:
> >Many major publications RELY on heavy advertising from the auto industry.
> >Like Millions of $$$ in advertising.
> >One cannot cut off the hand which feeds them.
> >These publications CANNOT print things which tick off the auto
> >industry (i.e. good things about blends, bad things about R-134a, etc)..
> >If they did that, all the big three + Japan would yank ALL their
> >adds.. for many months, causing the publication economic ruin.
>
> One problem with this conspiracy theory is that I've previously quoted
> similar articles from non-automotive journals, including the "Looming
> Ban on Production of CFCs, Halons Spurs Switch to Substitutes" from
> Chemical & Enginnering News Nov 15 1993 p12-18. "Ozone-Friendly
> Cooling" Popular Science July 1990 p57-63. "Replacing CFCs:The search
> for alternatives" Ambio Oct 1990 p329-333. HFC producers could also
> conspire
HFC producers also do conspire.. but not nearly to the degree
as the big 3 American Auto companies..Also the big HFC companies
and the big 3 auto companies cross own whole bunches of eatch other's
stock. Popular Science/Mechanics are majorly funded by auto
AD...as well as are most of the auto type mags...We typically see
a "Press Release" from Ward Atkinson of MACS first.. and then laugh
as it filters through all the mags.. almost same exact words, but
they change the author typically..One or two "non-aligned" rags
here and there will fight it.. They often get run out of business.
>
> Besides, GreenPeace has been strongly lobbying for the banning of
> R134a and its replacement by hydrocarbons, the lobbying is not all
> one-sided...
>
Almost nobody "in control" listens to Greenpeace in the US..
THere is way too much money to be made off HCFC/HFC's than to use
hydrocarbons.. (even in "approved" designed for new mfgr..)
Even if new auto production did use engineered systems for
hydrocarbons and all the hysteria was overcome.. they would
not happen over here.. since an auto recharge only uses
about $.50 of product.. Where as the same recharge can be
marked up to $200-$300 for blends/HCFCs/CFCs/HFCs...
> ....
> >Hindenburg, the Pinto, The side mounted Pickup truck gas tanks, etc..
> >(remember the rocket engine ignitors?? on the truck blowing up?)
>
> No, the flames weren't visible down here. :-)
The video had to be freeze-framed, and single stepped.. GM did that..
> According to Automotive News. Nov 8 1993 p1&45.
> "Late this summer, International Association Arson Investigators
> conducted tests with as liitle as 5.5 ounces of the OZ-12 material
> introduced into vehicle interior. "When the ignition source was
> activated, the result was an explosion that blew the windows
> out of the car," said a source with the State of Florida.....
> The air conditioner's evaporator, located in the firewall, would
> provide a possibleentry point for the material into a vehicle cabin."
We have seen lab tests create 10 foot fireballs from around 2oz of
R-12/oil mixtures..but as the above trials.. the probability of
real danger in real life (the validity) is very very very small..
One can pretty much design a test to show about any result as
long as you know what the outcome should be before the test is
designed..
>
> I've previously said that I accepted these trials probably weren't
> valid, but you continue to berate me...
Not berating you, just the auto industry over here..sorry it wasnt
directed at you..
>
> >The A/C only holds 1.5lbs or so of propane/isobutane. The gas tank
> >holds over 100lbs of gasoline.
This does not mean I am rooting for propane/isobutane refrigerant.. only
point out observations of things which have happened..and using that
as a worst case to show how almost all the harping on flammable refrigerants
is much ado about nothing., besides, doesnt NZ have zillions of propane
powered vehicles?
>
> >Oil, brake fluid, transmission fluid,
> >power steering fluid, are all EXTREMELY FLAMMABLE/EXPLOSIVE when they
> >drip on hot enging/exhaust components. Hydrocarbons have to be at a fuel/air
> >ratio of roughly between 2% - 8% by volume in air in order to ignite.
>
> All of which are located appropriately by the engineers designing the vehicle,
> taking due notice of the physical properties of the internal fluid. If they
> get it wrong and locate the gas tank where it can be hit, or make fuel
> pump diaphragms that expand/shrink due to gasoline aromatic/olefin
> concentration changes - resulting in major sprays of pressurised gasoline
> over the exhaust and alternator, they soon rectify it. In this case a
> non-flammable refrigerant is being replaced by a flammable one
> in an existing system.
>
> >In a hose break/leak, propane/butane dissipate rapidly, gasoline
> >hangs around, fuming, waiting for an ignition source.
> >R-12 systems contain approx 10-15% by volume of mineral oil, which
> >is dissolved in the refrigerant. A line rupture creates in "oil fog"
> >which can be quite explosive. A jet of R-12/oil mist leaking can be
> >ignited (I have a pix) and does sustain fire (looked like a flame-thrower).
>
> True, I didn't say it couldn't - however I don't have statistics on the
> number of R-12/oil fires, However I suspect the number is fairly low.
The 50,000 cars which used propane/isobutane didn't have any
reported flammability problems I heard either..
> Burning R-12 also produces toxic fumes, but let's put it this way -
> how many R-12 service people have you seen immolated using the
> flame copper halide, or heated Pt electronic leak detectors to test
> R12 systems. ( and yes, I'm aware the Cu flame test isn't appropriate
> for R-134a ). You must be aware that one of the major opponents to
> OZ-12 was the Mobile Air Conditioning Society - " The use of flammable
Try this one.. Discharging or leaking R-12 gets stucked into the air
intake of a running engine.. and "white smoke" pours out of the
exhaust...(this happened locally during service). R-12 decomposes
in the engine to HF & HCL both wicked substances.. fortuneately
they realized what happened and abandoned the place in a hurry..
> ....refrigerants poses safety concerns to the technicians servicing
> mobile air-conditioning systems" states an October 1993 bulletin from
> MACS. They're not bunny Usenet posters like I apparently am.
MACS is 700 people trying to control the destiny of 400,000
air service technicians..
>
> >That is why "those in charge" are VERY CAREFUL to specify flammability
> >specs WITHOUT the oil present, rather that what is really found in
> >a car A/C. When you include the compressor oil, all the refrigerants burn.
>
> You know as well as I, that the Test Method specified by the US Department
> of Transportation as the procedure for determining whether a compressed
> gas is classified as flammable or nonflammable is ASTM-E361, and has been
> for a very long time. If you want some data, refer " Flammability of
> alternative refrigerants" Robert G Richard, Ian R Shankland. ASHRAE
> Journal April 1992 p20-24. Table 4. Refrigerant Flammability
> Material, Flammable Range, temperature, Ignitionsource
> Propane, 2.1-9.6, RT, Match
> Butane, 1.5-10.1, RT, Match
> isoButane, 1.7-9.7, RT, Match
> R-134a, none, RT, Match.
I think the test is ASTM E-681, not E361 and it deals with gasses.
I have referenced the above paper in a paper I co-authored last year.
many halo-carbons (like R-142b, R-32, etc) have very "ragged" upper
flame limits, and are very difficult to determine.. since they
wont stay ignited.. Although R-142b (chlorodifluoroethane) as listed
as "flammable gas" in the US.. One cannot ignite a stream of it
vented from a tank.. In a "liquid spill", it can be make to burn
a little bit when ignited from a propane torch, but it goes out
by itself..A weird case: flammable but has no "flash point"..
The E681 has existed for a long time.. The point is that the people
"in control" chose to use E681 on the refrigerant ONLY.. verses E681
or similar test on refrigerant+oil mixture what is found in a real
life situation.. If refrigerant+oil was used, about anything would
burn, and it could not be used as a tool to keep out blends, etc..
Refrigerant+oil flammability is also "hush-hush" in the stationary
industry..
There are very many degrees of flammability , like the case of R-142b
above to hydrocarbons and to things even worse like acetylene and
ethers (4-100% and 5-35% in air).. acetylene will continue to
burn (polyermize with no oxygen present once started).
The public lumps them all into the "explosive" category.
For instance, we know from the movies, that a small fire
near the filler neck of a car's full gas tank results
in the explosion of the whole car as well as the filling
station going up too. Fires burn back up their fuel stream
until they reach the tank.. and boom....
The movie would not be fun.. if a small 2-3 inch flame formed
at the filler neck and was batted/blown out by the pump person..
The tank cannot explode since it does not contain 92-98% air
to put the gasoline in it's flammability range..
Take a big gasoline liquid spill, getting under all kinds of things,
producing fumes, etc... then igniting later.. now you have a scene
(e.g. Texas river fires were a few million gallons of gasoline got
released due to ruptured refinery pipelines from floods before
it went off..
> ( Yes they do use the electrically-activated match ignition source
> specified in ASHRAE Standard 34-1989 ( because many of the
ASHRAE even argues over the type of "match"..I as involved in some
"paper match" vs "kitchen" (strike-anywhere) match discussions..
The current standard is 34-1992 I think now.
If you want to see a paper I co-authored, and if you have Mosaic, check
out "http://ghg.ecn.purdue.edu" (my homepage), skip about 3/4
the way down. The first part of it is dumping Liquid Oxygen
on BBQ grills to light them. I may scan in the R-12 oil fire pix.
next week if I get time.
> halocarbons are difficult to ignite - maybe the OZ-12 Arson
> Investigators above didn't :-) ).
>
> > R-134a does become
> >flammable at just above atmospheric pressure (5 PSI). There have been
> >reports of R-134a explosions in refrigerant lines/compressors.. Workers
> >unsoldering lines (had air/R-134a in them), after letting out the
> >refrigerant, built up a small positive pressure, or the burning of
> >the oil at the joint raised the local pressure above 5 PSI, and blam.
> >Go figure for yourself.
I am not saying R-134a is bad, but it is being passed off as
"never" flammable, rather than being warned about flammable
above 5 PSIG.. If the tech knows the real story, then proper
precautions, such as not allowing a small residual pressure
buildup or a dry nitrogen purge first would be taken.
R-22 and almost all other HFC/HCFCs when mixed with large
amounts of air under pressure (50 PSIG or so) will burn explode..
But this is not commonly encountered. R-134a/air (if used for
pressurized leak testing) can be explosive if a torch heats
the outside of a pipe for instance. Not a real problem and
easy to avoid, just one has to be aware of what is going on.
>
> Refer above, the service technicians seem to prefer R-134a for
> retrofits rather than HCs, so would I. You may choose otherwise...
>
> >How many car makers'
> >production lines/service shops will take the care and scrupulous
> >techniques that a scientific lab does when building or servicing
> >R-134a systems or retrofits.
>
> Several makers support R-134a ( and I've previously posted on the
> data on the 2 years/million mile ICI trials - which also found none of the
> vehicles' owners took ICI up on their offer of a free retro-retrofit back
> to R-12 at the end of the trials). Volvo's low-priced scheme ( $45 parts, $21
> R-134a, estimated $200 for labor ) was intended to encourage owners to
> take the environmentally beneficial option,
>
>
> >What happens when production lines stop for awhile with "open"
> >A/C systems (drier soaking up water).. and shoddy service techniques
> >are applied to oils which are 10X or 100X more hydroscopic than
> >5GS?? go figure...
>
> Come on, these refrigerants probably still aren't as hydroscopic as
> glycol brake fluids, and the boiling point reduction caused by water
> is far more safety critical ( sudden, total loss of brakes ) - if necessary
> Toyota etc can show the US industry hoew they currently do it.
> We both know production lines can operate to produce low moisture
> systems.
While not as "safety related", A/C systems are much more easily
ruined by a few 10s to 100ppm of moisture.. All HFC/CFC/HCFCs
break down slowly into acids from residual moisture.. -134a
has a second strike against it, in the jact that it's oils
PAG & POEs are moisture sensitive as well.. I doubt that 100ppm
of moisture in glycol brake fluid will depress its boiling
point all that much.
> ....
> >Has anybody wondered if massive retrofit failures are the "solution"??
> >Gets lots of service business.. then gets the service (3rd party)
> >out of business when they fail after 6mo-year.. "You should have
> >gone to the dealer all along..." Now with unservicable A/C, consumers,
> >say "screw it", and trade up for a "new car".. 130-150 million R-12
> >cars out there.. go figure...
>
> Conspiracy theory - bad news travels fast. Long term players will
> provide long term solutions. I think I initially quoted from the July
> 1994 ( Car & Driver? ) article by Patrick Bedard " As carmakers do
> more testing, retrofits seem less of a nightmare..."
About a year ago, the MACS newsletter printed something to the
effect that GM retrofitted 60-some vehicles to R-134a, and in
5 months had > 25% compressor failures (using PAG oil).
I can't believe MACS printed that. then a total hush-hush on it.
>
> >> These people aren't bunnies, their retrofits are
> >>likely to meet their target specifications for performance and price.
>
> >Lots of room needed for beefing up things, no space in many compact
> >cars.. this means dozens of "custom" condensers need to be designed,
> >with custom fans, baffles, etc...a real integration problem. Plus
> >then you have the chloride/moisture problems to deal with.. How many
> >are going to do a "correct" retrofit, where everything which touches
> >refrigerant is replaced? About $1500 or more incl labor.. That one
> >solves the residual chloride problems. Esters don't have as good of
> >lubricity as do the Minerals or PAGs..
>
> We've been down this path ealier this year. the chloride/moisture
> problems can be overcome with appropriate selection of formulation
> and operational procedures. A "correct" retrofit doesn't involve a
> complete replacement. Refer above for the Volvo, ICI examples;
A "correct" retrofit may involve a trade-in of the vehicle for
a "new" R-134a system, which won't have the chlorides to contend with.
Also a "new" car will likely have 30% oversided condenser and increase
airflow to restore capacity to that which R-12 would give.
> and I'll repeat a quote from the above C&EN article " In 1991, the auto
> industry estimated retrofitting costs would range from $200-$1200 per car,
> depending on the make, model, and year.... But after a few years experience
> withretrofitted vehicles, it appears the high end of the cost range may
> have ben overestimated".
I have heard reports of users so unhappy with R-134a retrofits that
they want to illegal blends after removing the R-134a and were happy.
Almost any zeotropic blend whether it be propane/butane, R-400
series refrigerants would offer a great capacity increase with a
marginal condenser.. Anything but hydrocarbons stuck back in a former
R-134a system with PAG oil would pretty much trash the oil in short
order I would think.
> ...
> >Europe is using hydrocarbons now in new mfgr.. The main problem with
> >alternatives, is the damage to the pocketbooks of Detroit.
>
> I'm sure Detroit will listen carefully, especially if you offer complete
> indemmification for all A/C fire claims. Of course they might want
> to know that you have the $ to back it up. I've consistently said
> that I have no problem with HC designed/tested OEM systems.
>
> >Why is Australia using MP52 (R-401C) for retrofits instead of R-134a?
>
This (R-401C) was brought up at the 1994 CFC and Halon alternatives conference
which went on last week in Washington DC..I was told this on the phone.
My proceedings just arrived (it is 4" thick). I will try to track it
down more.
I have also noticed that at least some of the "CFC" conferences are
"rigged", esp in the automotive area. In the past, papers which
were not "yea 134a" got rejected, after acceptance. This has happened to
me & Dupont. I had a paper accepted for a 1992 CFC conference on a
refrigerant blend by Dr. Stephan Anderson, chief CFC scientist at the USEPA,
and the auto-industry managed to kill it as a "mistake", we forgot
about it, etc.. Ward Atkinson then gets quoted by the press
(Arizona Republic), "nobody has come up with a breakthrough, so we
will have to retrofit millions of cars to R-134a"... Ward Atkinson
was the session chair at the particular conference. Ward Atkinson
is the technical advisor for MACS/SAE as well.
Dupont has had papers on MP52 (now R-401C) taken out of conferneces also.
MP52 is on the EPA approved list in the US, but they appear to have
been "boycotted" by the auto industry into not selling it here.
MP52 does not need unstable PAG or POE oils.. It needs 80% alkylbenzene
oil, which is similar to mineral oil and is much more stable then
PAG or POE, so MP52 won't be destroyed by trace chlorides, mineral oil,
CFC-12 residue, etc...
Also MACS says "only 1 refrigerant (134a)" so service wont get confused,
but 47 types of PAG compressor oil are OK... go figure..
--ghg
Bruce Hamilton
>... g...@freedom.ecn.purdue.edu (George Goble) writes:
>>In article <B.Hamilton....@irl.cri.nz> you write:
>>...g...@freedom.ecn.purdue.edu (George Goble) writes:
>>>>... B.Ham...@irl.cri.nz (Bruce Hamilton) writes:
[ please remember that the following is a quote from a magazine ]
>>>kits and magic potions. An example is a refrigerant that's a mixture of
>>>propane and butane. "You don't have to change anything!" It'll cool.
>>>Lubrication is iffy. And if a leak gets sparked in the engine bay, Kaboom!"
>Remember the old pre-computer cars with carbs? How many times
>did people inadvertantly "flood" them by pumping the throttle
>too much? Remember you can to "floor" 'em and keep cranking
>until the over rich mixture was sucked into the engine and it
>leaned down until the upper flame limit was reached and the
>car started? Remember the smell of gasoline fumes in the
>passenger compartment? How much gasoline fumes do you think
>where under the hood then? Starter solenoid/commuter sparking..
>How many "flooded" cars actually blew up? Must not have been
>very many or we would have had a national outcry. Why is propane/
>butane refrigerant gonna be any worse if it is leaking. To even
>approach flamability limits, the leak has to be pretty severe
>(few hours or less)..
It may just have something to do with the fact that liquid gasoline
doesn't burn, only the vapours it gives off. At all temperatures
above -35C it produces sufficient vapours to burn in the closed
cup Flash Point test. But in real life sometimes the warmth and
air movement isn't available to generate sufficient vapour, _and_
mix it with air to yield a flammable mixture. If the mixture was
only flammable after being leaned down and mixed in the engine
there wasn't a great chance in the relatively static air in the engine
compartment of a stationary car.
Your product _is_ under pressure, _and_ will mix with air to produce a
flammable mixure without additional heat. Gasoline needs to be
vaporised and mixed with air. You must be aware that winter gasolines are
much more volatile than summer - to assist winter starting/prevent summer
vapour lock - although the EPA is planning on reducing the volatility
for environmental reasons. Correctly-formulated volatile winter gasolines
( with more propane, iso-butane, n-butane :-) ) make starting much easier
on carburetted cars. If you don't believe me, take some at 20C , shake it up,
vent the can, repeat several times until pressure no longer builds up.
Then try to cold start a carburetted car with that fuel.
Now as your mixture is similar to LPG, remember those stories of LPG
leaks in caravans with LPG stoves? :-) , and how they exploded
when ignited - leading toall those regulations about LPG installations on
mobile installations. I don't know about the US, but here in NZ the
safety requirements for the structural integrity ( in an accident)
of road and rail tank wagons for gasoline and LPG are hugely
different - something to do with an LPG or propylene? road tanker
tanker and the almost instant conversion of a holiday camp site in Spain
into a crematorium, if I recall correctly.
Your comment about "to approach flammable limits" obviously
depends on what volume of air you intend to make into a fuel/air
bomb. The size of a leak depends on the mechanism, I've never
seen a large "verandah" leak through bundy tubing, but then I've
never seen a small "pipe/hose fracture" leak either. YMMV.
OZ-12 auto A/C conversions represented <0.04% of the R-12 fleet,
and the service industry organisation was against HC refrigerants.
As I continue to say, I've no problem with automobile A/C using
carefully designed hydrocarbon refrigerant systems, providing
the system was designed, tested, approved for that application.
Such a purpose-engineered, clearly-labelled system is unlikely
to be significantly more risky to driver and all service people
( not just the A/C serviceperson ).
Bruce Hamilton
George Goble
Car is "flooded" since mixture is too rich in the carb..
outside the carb, under the hood, and possible in the
passenger compartment.. it may be in the flammable range..
remember you can smell it.. one may have raw gas dripping
out of the air cleaner or such now.. What if you get a "backfire"
while cranking? The starter turning the radiator fan should
stir it up quite fine.
>
>Your product _is_ under pressure, _and_ will mix with air to produce a
>flammable mixure without additional heat. Gasoline needs to be
>vaporised and mixed with air. You must be aware that winter gasolines are
>much more volatile than summer - to assist winter starting/prevent summer
>vapour lock - although the EPA is planning on reducing the volatility
>for environmental reasons. Correctly-formulated volatile winter gasolines
>( with more propane, iso-butane, n-butane :-) ) make starting much easier
>on carburetted cars. If you don't believe me, take some at 20C , shake it up,
>vent the can, repeat several times until pressure no longer builds up.
>Then try to cold start a carburetted car with that fuel.
It is a bitch.. take a spell of local winter at -10 or -20C..
so "winter gas" has lots of isobutane/butane in it.. filling is no
problem.. Now we get a sudden +10C day (50F or so)..
Can't even fill a tank or Jerry Can.. stuff is foaming so bad,
you can see all that butane/isobutane boiling out..
takes forever.. besides you may be losing 5-10% of the product
which boils off on the +10C day you dont get to use!
Shell's gas last year was real bad on winter gas on warm day!
I have believed you for years on this one.
>
>Now as your mixture is similar to LPG, remember those stories of LPG
You have me mixed up with "OZ-12". I was just using an extreme
example such as OZ-12 to show worst case scenarios.. and very
little if any flammability problems surfaced.. so things which
are much less flammable should have no problem.. Back in 1989
I made one batch of what would later be known as OZ-12 by others..
It was 79% propane and 21% isobutane.. I ran it in a car for 3 months
and abandoned it.. worked fine.. but friends of mine whom jump out
of planes every weekend, refused to ride in the car.. people
were joking about about 1.5lb of hydrocarbons leveling a parking
garage, etc... Because of this riddicule I dropped work on
hydrocarbons...
My current mixture, R-406A, is only (by weight) 4% R-600a (isobutane),
and 41% R-142b (chlorodifluoroethane), and 55% R-22 (chlorodifluoromethane).
Worst case fractionation scenarios are cold temps, like -20C, and
around 90% vapor leaked off... In this state it is around 3% isobutane
(max, usually 2), around 13% R-22, and 84% R-142b. Continuing the
leakout to 100% results on pure 142b at the very end. Near the
80% vapor leakout point R-406A may exhibit very weak flammability, but
no flash point.. Pure R-142b also has very weak flammability and
no flash point.. The remaining R-22 near the end more than
midigates the effect of 2-3% isobutane. Opening a tank, for
a slow vapor or liquid leak, and a propane torch, worst case
fractionated R-406A will not light up. Taking a "puddle" (worst case) of
liquid and a propane torch, one can get it to ignite, but it
goes out after a second or two.. the decomposition products
quench it. There is still no "flash point". The heat of combustion
is around 1/10 of that of hydrocarbons.. "rate" of combustion
(pressure rise) in an E681 test.. are much much lower..
Ammonia burns much faster (LFL-UFL 15-25%) and it is US-DOT
nonflammable.
We gave up on on automotive airconditioning because of all the
political fighting from MACS and the auto industry in the US..
Whenever something gets close, they have to power to change
the playing field (rules) at will.. Much of the refrigeration and A/C
sections of the US "Clean Air Act" were drafted with their "assistance".
"They" even got President Clinton to get Dupont to crank out
an extra year of R-12 production..after the EPA refused.. so
you know how powerful the auto industry is. They also boycotted
an EPA approved blend, MP52 (R-401C), into not being marketed
in the US for autos. If the auto industry can do that to a $33 billion
company, there is no chance for the "little guy" in an arena
like that.. It is not just an unlevel playing field, the playing
field is inverted.
>leaks in caravans with LPG stoves? :-) , and how they exploded
>when ignited - leading toall those regulations about LPG installations on
>mobile installations. I don't know about the US, but here in NZ the
>safety requirements for the structural integrity ( in an accident)
>of road and rail tank wagons for gasoline and LPG are hugely
>different - something to do with an LPG or propylene? road tanker
>tanker and the almost instant conversion of a holiday camp site in Spain
>into a crematorium, if I recall correctly.
I remember the tanker (propane), wasn't it in Mexico, it
got 300-500 people?
>
>Your comment about "to approach flammable limits" obviously
>depends on what volume of air you intend to make into a fuel/air
>bomb. The size of a leak depends on the mechanism, I've never
>seen a large "verandah" leak through bundy tubing, but then I've
>never seen a small "pipe/hose fracture" leak either. YMMV.
>OZ-12 auto A/C conversions represented <0.04% of the R-12 fleet,
>and the service industry organisation was against HC refrigerants.
Portions of the Florida service industry were "for" OZ-12.. and
business was going like gangbusters for 2 or 3 months.. before
the rigged explosions.
Lots of people are still using it "illegally".. They were supposed
to have is removed and replaced with R-12.. but they decided to
keep it even with all the flammability hoopla.. they know you
have 100lbs of gasoline onboard and made their decisions..
>
>
> Bruce Hamilton
--ghg
Bruce Hamilton
g...@freedom.ecn.purdue.edu (George Goble) writes:
> B.Ham...@irl.cri.nz (Bruce Hamilton) writes:
>>> g...@freedom.ecn.purdue.edu (George Goble) writes:
....
>Car is "flooded" since mixture is too rich in the carb..
>outside the carb, under the hood, and possible in the
>passenger compartment.. it may be in the flammable range..
>remember you can smell it.. one may have raw gas dripping
>out of the air cleaner or such now.. What if you get a "backfire"
>while cranking? The starter turning the radiator fan should
>stir it up quite fine.
I have plenty of times - almost every time I pulled my Vauxhall
Viva engine apart and was trying to first-time start, and not
to mention the older engines ( Standard Vanguard 10,
Ford 10 ) which did have mechanical fans. I can recall the
fuel dribbling from the little flooding pipe down the exhaust
manifold onto the generator.
I recall caution, not fear, never had a fire from backfires - yet.
>>Now as your mixture is similar to LPG, remember those stories of LPG
>You have me mixed up with "OZ-12". I was just using an extreme
>example such as OZ-12 to show worst case scenarios.. and very
>little if any flammability problems surfaced..
My mistake :-(.
I hadn't actually seen what GHG-12 had in it. I was arguing
against OZ-12-type material - sorry that I included yours in
that.
> so things which are much less flammable should have no problem..
Less problem :-).
>My current mixture, R-406A, is only (by weight) 4% R-600a (isobutane),
>and 41% R-142b (chlorodifluoroethane), and 55% R-22 (chlorodifluoromethane).
>Worst case fractionation scenarios are cold temps, like -20C, and
>around 90% vapor leaked off... In this state it is around 3% isobutane
>(max, usually 2), around 13% R-22, and 84% R-142b. Continuing the
>leakout to 100% results on pure 142b at the very end. Near the
>80% vapor leakout point R-406A may exhibit very weak flammability, but
>no flash point.. Pure R-142b also has very weak flammability and
>no flash point.. The remaining R-22 near the end more than
>midigates the effect of 2-3% isobutane. Opening a tank, for
>a slow vapor or liquid leak, and a propane torch, worst case
>fractionated R-406A will not light up. Taking a "puddle" (worst case) of
>liquid and a propane torch, one can get it to ignite, but it
>goes out after a second or two.. the decomposition products
>quench it. There is still no "flash point". The heat of combustion
>is around 1/10 of that of hydrocarbons.. "rate" of combustion
>(pressure rise) in an E681 test.. are much much lower..
You obviously realise that flash point is recognised as
inappropriate for materials where combustion products
may smother the flame, but the liquid would ignite if
they were displaced - even the TAG open cup doesn't
cope with such materials. The comparison should
be against the refrigerant the system was designed
for - yours is certainly far more preferable to OZ-12 :-).
>"They" even got President Clinton to get Dupont to crank out
>an extra year of R-12 production..after the EPA refused.. so
>you know how powerful the auto industry is.
Given that the US Govt. apparently will collect an additional
$400 million from the punitive taxes on that product, I suspect
Clinton didn't take much "getting" :-).
>>... - something to do with an LPG or propylene? road tanker
>>tanker and the almost instant conversion of a holiday camp site in Spain
>>into a crematorium, if I recall correctly.
>I remember the tanker (propane), wasn't it in Mexico, it
>got 300-500 people?
I think Mexico was the pipeline failure, Spain/Portugal? was the
Road Tanker that failed to take a bend ( brakes ) and crashed
down into a camping ground. 1970s?.
Bruce Hamilton
Greg Marciniak
|> As George Goble has pointed out, the refrigerant blend he has invented,
|> "GHG Refrigerant-12 Substitute", designated R-406A by ASHRAE, has been
|> designated as an acceptable substitute for R-12 in a variety of
|> applications by USEPA -- but not for use in mobile A/C.
|>
|> Discussion on the net has mostly focused on the question of flammability.
|> I thought readers might be interested to see what EPA itself has said with
|> regard to R-406A.
|>
|> This is taken from the Federal Register of 26 August 1994, in a "notice
|> of acceptability" under EPA's Significant New Alternatives Policy program:
|>
|> > (a) R-406A.--R-406A, which consists of HCFC-22, HCFC-142b, and
|> > isobutane, is acceptable as a substitute for R-500 in retrofitted
|> > centrifugal chillers. Because HCFC-22 and HCFC-142b contribute to ozone
|> > depletion, this blend is considered a transitional alternative.
|> > Regulations regarding recycling and reclamation issued under section
|> > 608 of the Clean Air Act apply this blend. HCFC-142b has one of the
|> > highest ODPs among the HCFCs. The GWPs of HCFC-22 and HCFC-142b are
|> > somewhat high. Although HCFC-142b is flammable, the blend is not. After
|> > significant leakage, however, this blend may become weakly flammable.
|>
|> The notice goes on to declare R-406A an acceptable substitute in a
|> long list of applications. I can post the list (or ghg can, since
|> it's his stuff :) ) if there is interest...
|>
|> I'd be curious to hear if George Goble himself has something to add
|> to this.
|>
|> I'll post something later about EPA's current thinking about mobile A/C.
|>
|> Btw, this sort of discussion would probably be welcome in the
|> "environmental tech" group we keep discussing creating someday.
|>
|> --
|> Gregory
My guess here is the keyword that R142b has one of the highest
ODPs among HCFCs. ODP is Ozone Depletion Potential. So the
components of R406A are primarily HCFCs and isobutane. Granted
HFCFs as a group have less ODP than CFCs(like R12) but maybe the
EPA didn't want something with ODP at all in cars which comprise
a lot of refrigerant.
Greg Marciniak
George Goble
>g...@freedom.ecn.purdue.edu (George Goble) writes:
>>> >The A/C only holds 1.5lbs or so of propane/isobutane. The gas tank
>>> >holds over 100lbs of gasoline.
>>This does not mean I am rooting for propane/isobutane refrigerant.. only
>>point out observations of things which have happened..and using that
>>as a worst case to show how almost all the harping on flammable refrigerants
>>is much ado about nothing.,
>
>Oh..... Really?....
>I can't see how I could have otherwise interpreted it...
>I've obviously misunderstood your position :-(
>I'm now confused, Gregory has kindly posted the federal
>registor, and lists GHG-12 as a zeotropic blend that can
>become flammable. From earlier JdA raves I thought you
^
"weakly flammable"
I made a video tape showing this when the Safety paper was
presented last summer.. I may digitize some segments
showing "weak" flammability and add them to my homepage if
anybody is interested.. There is also a comparison to
lighting up 8oz of propane and kicking it over.
R-406A is undergoing further safety testing/classification
at UL and other safety testing organizations. Work is also
underway on risk assesments.
>were also pushing a totally HC refrigerant?.
JdA seems to have vanished from the net a couple of months back..
nobody knows what happened to him for sure. Back in 1989, JdA
made a net posting about propane & butane:
|From pur-ee!mentor.cc.purdue.edu!purdue!gatech!emcard!stiatl!rsiatl!jgd Sat Oct 7 18:25:30 EST 1989
|Article 766 of sci.energy:
|Path: en.ecn.purdue.edu!pur-ee!mentor.cc.purdue.edu!purdue!gatech!emcard!stiatl!rsiatl!jgd
|>From: j...@rsiatl.UUCP (John G. De Armond)
|Newsgroups: sci.energy
|Subject: Re: Refrigerator efficiency (was Re: energy sources discussed)
|Message-ID: <2...@rsiatl.UUCP>
|Date: 4 Oct 89 07:42:46 GMT
|References: <16...@brunix.UUCP> <44...@cbnewsh.ATT.COM> <45...@internal.Apple.COM>
|Reply-To: j...@rsiatl.UUCP (John G. De Armond)
|Organization: Radiation Systems, Inc. (a thinktank, motorcycle, car and gun works facility)
|Lines: 178
|
|[much stuff deleted]
|>
|>NH3 can be nasty stuff, hydrocarbons are flamable, etc.
|Plus the hydrocarbons, such as butane and propane are not too hot as
|refrigerants.
|
|[stuff deleted]
------
I went out in the spring of 1990, and ran a mixture of 79% (wt)
propane/21% isobutane in 1 car.. and it ran fine and posted this
to the net. Suddenly, JdA became a raving supporter of
HC refrigerants, and touted them for 4 years.. Much later somebody
else "invented" OZ-12, which was pretty much the same thing.
I gave up work on this due to the flammability 2 months later.
Other's on the net, seemed to accept the risks of HC flammability
and wanted to "roll their own" R-12 substitutes. There was lots
of discussion about how to mix, charge, etc.. JdA was very active
in all that. He also ran GHG R-12 substitute (R-406A) and touted
that..
In passing to a response on home mixing HCs for A/C, I mentioned a recipe:
Get 6oz can of isobutane camping fuel...
Get 16oz can of propane (for a torch)
crock up necessary plumbing to get the above into
a refrigeration gauge set. JC Whitney's sells Freon can side-tapper
which works on the isobutane.
Evacuate system as normal with a vacuum pump.
Charge in the isobutane
Charge in the propane.
This is approx the correct mixture and correct amount to
run an R-12 3lb system on a typical car.. No mixing, weighing, etc.
I assume no liability if you burn/blow yourself up.
JgA pushed this also.. and several net users did it, and it worked
and they seemed to be happy...
However, this has caused much of the public to wrongly equate GHG-12 or GHG-
R-12 substitute with being all hydrocarbons (i.e. OZ-12)
It is a neverending problem to set this straight.
>
>My position has always been that retrofits of highly flammable
>HCs (OZ-12 ) into systems designed for non-flammable CFCs.
>I'm a little more ambiguous on blends such as R-406a that can
>become flammable, but as it has HCFC-22, and HCFC-142b -
>which both have higher GWPs than HFC-134a, it's likely to be
>even more transitional than HFC-134a.
>
R-406A was never intended to be anything else but a "transition"
to R-134a.. to keep CFC-12 equipment running until end of normal
life.. R-406A GWP is around 89% less then GWP of R-12, the
thing it replaces. We are getting numerous inquiries from OEMs
(stationary equipment) who are having problems getting new mfgr
R-134a equipment to hold up and are thinking about using R-406A
until R-134a problems can be worked out.
>
>>Try this one.. Discharging or leaking R-12 gets stucked into the air
>>intake of a running engine.. and "white smoke" pours out of the
>>exhaust...(this happened locally during service). R-12 decomposes
>>in the engine to HF & HCL both wicked substances.. fortuneately
>>they realized what happened and abandoned the place in a hurry..
>
>Well, if servicepersons had tried the same trick with OZ-12, I'd guess
>the chances of ignition in the engine compartment before the refrigerant
>got to the intake would be reasonable - they may have received assistance
>abandoning the place. I'm aware of the HF and HCl problem, as is any
>refrigeration/A/C serviceperson.
Somebody tried this on the net, blowing off a propane/isobutane full
charge with the engine running on a junk car.. with fire ext
handy.. nothing happened. quite to his amazment I am sure..
>
>>Dupont has had papers on MP52 (now R-401C) taken out of conferneces also.
>>MP52 is on the EPA approved list in the US, but they appear to have
>>been "boycotted" by the auto industry into not selling it here.
>>MP52 does not need unstable PAG or POE oils.. It needs 80% alkylbenzene
>>oil, which is similar to mineral oil and is much more stable then
>>PAG or POE, so MP52 won't be destroyed by trace chlorides, mineral oil,
>>CFC-12 residue, etc...
>
>I suspect alkylbenzene oils will be shown to produce toxic
>compounds during use, and will have to be disposed of as
>hazardous waste :-)
>
I haven't seen this to be the case (yet).. I will keep watching..
>>Also MACS says "only 1 refrigerant (134a)" so service wont get confused,
>>but 47 types of PAG compressor oil are OK... go figure..
>
>True, but my impression was that the MACS main concern was safety.
>Also, the article I read quoted Simon Oulouhojian ( President and
>Excutive director ) of MACS.
NACS has managed to stop anything (but 134a) which has gotten EPA
approval for an automotive A/C retrofit refrigerant before it
got to market.. even if it was totally nonflamable and made by
companies worth tens of billions of $$$. We subscribe to the MACS
newsletters and sometimes attend their meetings..
Before the creation of SNAP, we were at a MACS meeting in Orlando, Fl.
(jan 1993?)
Lena Nirk of the USEPA announced that the EPA had found nothing
wrong with any of the blends (MP52 and GHG) for environmental
reasons, and was getting ready to "approve" them. She said they
only objections to blends were "business" reasons.
You should have heard MACS fume and blow their top on that one.
Four-five days later, and order came down from cabinet level to
the director of the EPA to "ban the blends".. go figure...
>
> Bruce Hamilton
--ghg
Daniel J. Stern
SL6 Dan
George Goble
The list is pretty much everything (for R-12/R-500 retrofit) except
for MVAC (cars and mobile A/C which cools people..).. OK for
Mobile refrigerated cargo though.. (that counts as stationary) --ghg
>|>
>|> I'll post something later about EPA's current thinking about mobile A/C.
>|>
>|> Btw, this sort of discussion would probably be welcome in the
>|> "environmental tech" group we keep discussing creating someday.
>|>
>|> --
>|> Gregory
>
> My guess here is the keyword that R142b has one of the highest
> ODPs among HCFCs. ODP is Ozone Depletion Potential. So the
> components of R406A are primarily HCFCs and isobutane. Granted
> HFCFs as a group have less ODP than CFCs(like R12) but maybe the
> EPA didn't want something with ODP at all in cars which comprise
> a lot of refrigerant.
>
>Greg Marciniak
R-406A is (by wt) 55% HCFC-22 41% HCFC-142b and 4% R-600a (isobutane)
ODP of HCFC-22 is .055 ODP of HCFC-142b is .065 ODP of R-600a is 0.0
This gives ODP of R-406A as .0569
ODP of R-12 is 1.000
As a group the HCFCs are all grouped in a bunch at ODPs of .03-.06
which is a twentyfold reduction of ODP compared to R-12. Currently
EPA class II substances (HCFCs) are permitted in some forms all
the way out to around 2030..Various phaseouts and other stipulations
are placed on HCFCs (like ok for service but not new mfgr, etc)
at earlier dates (around 2010 or so?) and are different in different
countries.. This area is in constant flux.
ODP is not the reason for R-406A not being on the automotive list.
R-406A (GHG R-12 substititute at the time) was withdrawn (by the mfgr) from
the EPA automotive SNAP MVAC section over a year ago, due to the "bad"
political climate in the automotive industry towards blends. For
EPA Approval, it appears that the "industry involved" has to
"request" the EPA to approve it.. With the exception of the "slip up"
on FRIGC, how many auto companies are going to request EPA approval
to get blends in? All the auto companies (and MACS) spend large
sums of money to eliminate anything but -134a.
R-406A was "requested" by some members of the stationary
refrigeration industry.. The stationary industry is not like
"fighting with a bunch of mean junkyard dogs" like the auto industry was.
--ghg
Bruce Hamilton
Conspiracy theory stuff deleted - We're just not agreeing on that,
lets go our own ways.
>There is way too much money to be made off HCFC/HFC's than to use
>hydrocarbons.. (even in "approved" designed for new mfgr..)
>Even if new auto production did use engineered systems for
>hydrocarbons and all the hysteria was overcome.. they would
>not happen over here.. since an auto recharge only uses
>about $.50 of product.. Where as the same recharge can be
>marked up to $200-$300 for blends/HCFCs/CFCs/HFCs...
No, if there are cost advantages and no bad perceptions ( safety )
then an auto manufacturer would use it.
...
>> >The A/C only holds 1.5lbs or so of propane/isobutane. The gas tank
>> >holds over 100lbs of gasoline.
>This does not mean I am rooting for propane/isobutane refrigerant.. only
>point out observations of things which have happened..and using that
>as a worst case to show how almost all the harping on flammable refrigerants
>is much ado about nothing.,
Oh..... Really?....
I can't see how I could have otherwise interpreted it...
I've obviously misunderstood your position :-(
I'm now confused, Gregory has kindly posted the federal
registor, and lists GHG-12 as a zeotropic blend that can
become flammable. From earlier JdA raves I thought you
were also pushing a totally HC refrigerant?.
My position has always been that retrofits of highly flammable
HCs (OZ-12 ) into systems designed for non-flammable CFCs.
I'm a little more ambiguous on blends such as R-406a that can
become flammable, but as it has HCFC-22, and HCFC-142b -
which both have higher GWPs than HFC-134a, it's likely to be
even more transitional than HFC-134a.
> besides, doesnt NZ have zillions of propane powered vehicles?
By 1987 NZ had retrofitted around 135,000 CNG and 45,000 LPG vehicles,
however that number has reduced significantly - in part because a CNG
tank exploded ( Italian tank, metal too hard = brittle - manufacturer always
claimed it wasn't a manufacturing fault. ) and a much more aggressive
testing regime was introduced - many owners couldn't be bothered with all the
hassle and removed their CNG kits. The advent of cheap Japanese
second-hand cars into the market also resulted in the retirement of a lot
of converted vehicles. The conversions have always been strictly regulated,
and installers have to be trained and certified. In part this is because they
are retrofits.
>> True, I didn't say it couldn't - however I don't have statistics on the
>> number of R-12/oil fires, However I suspect the number is fairly low.
>The 50,000 cars which used propane/isobutane didn't have any
>reported flammability problems I heard either..
An earlier post of mine noted that 50,000/140,000,000 isn't a big number,
especially given the relative operational lifetimes as well.
>> Burning R-12 also produces toxic fumes, but let's put it this way -
>> how many R-12 service people have you seen immolated using the
>> flame copper halide, or heated Pt electronic leak detectors to test
>> R12 systems. ( and yes, I'm aware the Cu flame test isn't appropriate
>> for R-134a ). You must be aware that one of the major opponents to
>> OZ-12 was the Mobile Air Conditioning Society - " The use of flammable
>Try this one.. Discharging or leaking R-12 gets stucked into the air
>intake of a running engine.. and "white smoke" pours out of the
>exhaust...(this happened locally during service). R-12 decomposes
>in the engine to HF & HCL both wicked substances.. fortuneately
>they realized what happened and abandoned the place in a hurry..
Well, if servicepersons had tried the same trick with OZ-12, I'd guess
the chances of ignition in the engine compartment before the refrigerant
got to the intake would be reasonable - they may have received assistance
abandoning the place. I'm aware of the HF and HCl problem, as is any
refrigeration/A/C serviceperson.
>> ....refrigerants poses safety concerns to the technicians servicing
>> mobile air-conditioning systems" states an October 1993 bulletin from
>> MACS. They're not bunny Usenet posters like I apparently am.
>MACS is 700 people trying to control the destiny of 400,000
>air service technicians..
If the other 399,300 mobile A/C technicians ( that seems a very large
number? - maybe you should try to keep the Japanese out of the servicing,
they're likely to lose some of those jobs with improved A/C servicing )
are unhappy with MACS, they can also lobby.
>> >That is why "those in charge" are VERY CAREFUL to specify flammability
>> >specs WITHOUT the oil present, rather that what is really found in
>> >a car A/C. When you include the compressor oil, all the refrigerants burn.
>> You know as well as I, that the Test Method specified by the US Department
>> of Transportation as the procedure for determining whether a compressed
>> gas is classified as flammable or nonflammable is ASTM-E361, and has been
>> for a very long time.
>I think the test is ASTM E-681, not E361 and it deals with gasses.
Yes, My fault - I shouldn't have relied on memory for the number.
It deals with chemicals, refer below
> Although R-142b (chlorodifluoroethane) as listed
>as "flammable gas" in the US.. One cannot ignite a stream of it
>vented from a tank.. In a "liquid spill", it can be make to burn
>a little bit when ignited from a propane torch, but it goes out
>by itself..A weird case: flammable but has no "flash point"..
This is quite common, many chemicals do this, especially
when the combustion products actively inhibit further
combustion. A weird case is formic acid. The flashpoint decreases
when it's diluted with 10% water :-)
>The E681 has existed for a long time.. The point is that the people
>"in control" chose to use E681 on the refrigerant ONLY.. verses E681
>or similar test on refrigerant+oil mixture what is found in a real
>life situation.. If refrigerant+oil was used, about anything would
>burn, and it could not be used as a tool to keep out blends, etc..
>Refrigerant+oil flammability is also "hush-hush" in the stationary
>industry..
What I meant to emphasise was the fact that the test is not part
of a conspiracy, but has been the standard test for flammability
for ages - it deals with chemicals, the flask is heated above the
vapour condensation temperature, and that is obviously not
possible for oil/gas aerosols. The refrigeration and chemical
industries have used this method for a long time. Oil/refrigerant
mixes can not be tested by this method because of condensation
on the flask walls. Testing the flammability of aerosols using
other methods is possible, but very tricky - the size and surface
area have profound effects. Look at the difficulty of testing
the explosiveness of dust mixtures.
>There are very many degrees of flammability , like the case of R-142b
>above to hydrocarbons and to things even worse like acetylene and
>ethers (4-100% and 5-35% in air).. acetylene will continue to
>burn (polyermize with no oxygen present once started).
Sure, but acetylene can be ignited just by a >30psi pressure pulse,
that's why gas-axe acetylene cylinders contain acetone in porous
material to dissolve the acetylene, and acetylene also forms
explosive copper acetylides, thus the prohibition on copper pipes.
I don't see anyone planning on retrofitting CFC refrigeration
systems for use with acetylene staying in business long :-).
Most countries have rules covering flammable and hazardous
materials. The main reason I oppose the retrofitting of auto A/Cs
is because the systems were not designed for flammable refrigerants.
>Take a big gasoline liquid spill, getting under all kinds of things,
>producing fumes, etc... then igniting later.. now you have a scene
>(e.g. Texas river fires were a few million gallons of gasoline got
>released due to ruptured refinery pipelines from floods before
>it went off..
>ASHRAE even argues over the type of "match"..I as involved in some
>"paper match" vs "kitchen" (strike-anywhere) match discussions..
>The current standard is 34-1992 I think now.
True- I wasn't aware you had read the paper, and I wanted to forestall
a claim :-), they can only use what was current then.
> If you want to see a paper I co-authored, and if you have Mosaic, check
>out "http://ghg.ecn.purdue.edu" (my homepage), skip about 3/4
>the way down. The first part of it is dumping Liquid Oxygen
>on BBQ grills to light them. I may scan in the R-12 oil fire pix.
>next week if I get time.
I'll take a peek sometime, thanks.
...
>> We both know production lines can operate to produce low moisture
>> systems.
>While not as "safety related", A/C systems are much more easily
>ruined by a few 10s to 100ppm of moisture.. All HFC/CFC/HCFCs
>break down slowly into acids from residual moisture.. -134a
>has a second strike against it, in the jact that it's oils
>PAG & POEs are moisture sensitive as well.. I doubt that 100ppm
>of moisture in glycol brake fluid will depress its boiling
>point all that much.
It depends, If you want, plot the following.
Water content ( ppm ) : Brake Fluid Boiling Point ( degrees C )
1000 295
2000 262
5000 243
10000 224
25000 186
50000 147
100000 122
So you'll see that 100ppm has significant effects on anhydrous fluid.
Incidently, you'll find that in real life systems the boiling point can
drop to 240C in 2 months, 218C in 4 months, 200C in 6 months,
165C in 12 months, 137C in 24 months ( from a 1970s UK survey ).
That's why significant improvements to the brake fluids and
hermetic sealing of reserviors were made during the 1980s.
240C was considered the minimum for disk brake systems.
The A/C has a drier that can hold up to 20+% of its mass in moisture,
this is a historical acknowledgement of the fact that original systems
are not anhydrous, and retrofits also take notice of this. The issue
of moisture sensitivity of the lubricant has been addressed by the
manufacturers of the lubricant, that's why various additives and
procedural recommendations have been made..
The automobile A/C industry has been happy to thrive in a situation
where CFCs were cheap and leak rates were 0.15-0.25 pound annually.
The new R-134a systems leak less, and there is a real incentive to
reduce leaks further, due to the high price. Americans were content
to have whatever Detroit said they should like - until the Japanese
arrived and gave the public what they wanted. Perhaps the same
will happen with the currenmt A/C dinosaur systems.
>About a year ago, the MACS newsletter printed something to the
>effect that GM retrofitted 60-some vehicles to R-134a, and in
>5 months had > 25% compressor failures (using PAG oil).
>I can't believe MACS printed that. then a total hush-hush on it.
Maybe GM should talk to ICI and Volvo...
>A "correct" retrofit may involve a trade-in of the vehicle for
>a "new" R-134a system, which won't have the chlorides to contend with.
Possible, but unlikely.
>Also a "new" car will likely have 30% oversided condenser and increase
>airflow to restore capacity to that which R-12 would give.
The Condenser will not be "oversized", it will be of "appropriate" size,
given the different properties of the refrigerant. :-)
>Dupont has had papers on MP52 (now R-401C) taken out of conferneces also.
>MP52 is on the EPA approved list in the US, but they appear to have
>been "boycotted" by the auto industry into not selling it here.
>MP52 does not need unstable PAG or POE oils.. It needs 80% alkylbenzene
>oil, which is similar to mineral oil and is much more stable then
>PAG or POE, so MP52 won't be destroyed by trace chlorides, mineral oil,
>CFC-12 residue, etc...
I suspect alkylbenzene oils will be shown to produce toxic
compounds during use, and will have to be disposed of as
hazardous waste :-)
>Also MACS says "only 1 refrigerant (134a)" so service wont get confused,
>but 47 types of PAG compressor oil are OK... go figure..
True, but my impression was that the MACS main concern was safety.
Also, the article I read quoted Simon Oulouhojian ( President and
Excutive director ) of MACS.
Bruce Hamilton