Can I use butane torch to loosen this A/C hose fitting? - PeachParts Mercedes-Benz Forum

funola · #1 06-21-2017, 10:31 PM

Don't be fooled by scare tactics. The chance of propane or any hydro carbon refrigerant starting a fire in an accident is extremely small.

The Flammable Range (Explosive Range) is the concentration range of a gas or vapor that will burn (or explode) if an ignition source is introduced.

Three basic requirements must be met for explosion to take place:

flammable substance - fuel
oxidizer - oxygen or air
source of ignition - spark or high heat
Below the explosive or flammable range the mixture is too lean to burn and above the upper explosive or flammable limit the mixture is too rich to burn. The limits are commonly called the "Lower Explosive or Flammable Limit" (LEL/LFL) and the "Upper Explosive or Flammable Limit" (UEL/UFL).

Gases - Explosion and Flammability Concentration Limits

Here's a study done on HC refrigereant http://fam-bjork.se/citroen/AC/external/cfca95.pdf

This is copied from the study "There are now over 200,000 car air-conditioners using HC refrigerant and over
400,000 operating years have been accumulated. No accidents in which hydrocarbon
refrigerant caused damage or injury due to its flammability have been reported
to manufacturers or safety authorities yet."

leathermang · #2 06-21-2017, 11:06 PM

Quote:

Originally Posted by funola

Don't be fooled by scare tactics. The chance of propane or any hydro carbon refrigerant starting a fire in an accident is extremely small.

The Flammable Range (Explosive Range) is the concentration range of a gas or vapor that will burn (or explode) if an ignition source is introduced.

Three basic requirements must be met for explosion to take place:

flammable substance - fuel
oxidizer - oxygen or air
source of ignition - spark or high heat
Below the explosive or flammable range the mixture is too lean to burn and above the upper explosive or flammable limit the mixture is too rich to burn. The limits are commonly called the "Lower Explosive or Flammable Limit" (LEL/LFL) and the "Upper Explosive or Flammable Limit" (UEL/UFL).

Gases - Explosion and Flammability Concentration Limits

Here's a study done on HC refrigereant http://fam-bjork.se/citroen/AC/external/cfca95.pdf

This is copied from the study "There are now over 200,000 car air-conditioners using HC refrigerant and over
400,000 operating years have been accumulated. No accidents in which hydrocarbon
refrigerant caused damage or injury due to its flammability have been reported
to manufacturers or safety authorities yet."

""" Extremely Small '''' TRUE... but I do not want to be that exception when it is easy to avoid the chance completely...

I know you are some kind of engineer of some kind...... and that exposition looks impressive to many people..

The problems are numerous with your description... the flammable refrigerant in question would ALSO have OIL dissolved in it.... so under pressure and an escape route it would be sprayed out into the immediate area...

Now you may be too young to have ever used a Manual Choke on a car or riding lawnmower ... or anything..

But the procedure when using a manual Choke... is that you pull it to choke the engine....which causes an overly rich mixture to be entering the cylinders.. and then you disengage the manual Choke

WHILE

continuing to crank the engine...

THUS the fuel to air mixture goes THROUGH the range from TOO Rich.. to ( if the ignition is firing the spark plugs ) to the right mixture... where upon the engine cranks....

If you have hot spots... or sparks ... extant when the flammable refrigerant with its dissolved oil is sprayed into the area... then you risk the natural forces.. like the normal movement of air... causing that ' overly rich ' example to run move through to less rich and potentially flammable concentrations.. just like the manual choke being disengaged with the engine still pulling in fresh air....

And then there are the examples of GRAIN Elevators exploding.... and example of DUST mixed with just plain AIR... and a spark from normal static electricity causing deaths regularly...

That ''' extremely small chance'''' you go to the trouble to share with people... again.... is an example of YOU , the person making the case , of having NO SKIN in the game if that ' small chance' does harm someone.....

You also imply that the authorities which have not been notified yet of ''' manufacturers or safety authorities yet''' would have been notified .. when all the rest of your arguments on this forum display a healthy skepticism of manufactures and governmental authorities..... It may just be that no one investigating an accident which was aggravated by a flammable refrigerant was smart enough to check for that... and if the car burned to the ground... i don't know if they would be able to determine what refrigerant was used...

Anyway... I have expressed my case as well as I can... there IS A chance for a flammable refrigerant to aggravate a crash and that might be the difference between LIFE and DEATH.... and it is EASY TO AVOID that risk Completely...
To me that is a no brainer of a choice..

BillGrissom · #3 06-23-2017, 12:26 AM

Quote:

Originally Posted by funola

... No accidents in which hydrocarbon refrigerant caused damage or injury due to its flammability have been reported ..."

Pretty much, except an AC guy in Australia got some press by staging a combustion event w/ HC refrigerant. Duracool long ago paid for an engineering analysis which calculated that even if the full charge leaked into the passenger compartment in 5 min, with no outside air exchange, even that would not form a combustible mixture. Add to that you would need a spark, you would first smell the mercaptin (scent added to natural gas), even tight houses exchange their air w/ outside every hour (cars are leakier), plus most refrigerant leaks would be in the engine bay where hoses degrade faster.