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  1. #1
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    What exactly is a “nonflammable” refrigerant?



    So I got bored yesterday, so I decided to do my own flammability test of R134A refrigerant. Yes I know about the dangerous fumes produced. What I did is I set up my butane torch to stay lit, and I sprayed a small amount of R134A vapor on the flame. I was expecting it to blow the flame out, but to my surprise, the stuff burned! It didn’t support combustion, but it burned pretty well when the torch was held to it. So how could that be “non flammable”? I did some research, and I found on a few MSDS sheets that it can burn, but only under certain conditions, like high oxygen concentration or pressures above atmospheric pressure.

    So what exactly is the definition of a “non flammable” refrigerant? Does that just mean it won’t support combustion? And after seeing how well R134A burns even though classified as not flammable, it’s a bit scary to think about a “mildly flammable” refrigerant, like R1234YF. Not because I’m afraid of flammable refrigerants, but because it is labeled as “mildly flammable” when it is probably actually “highly flammable”.
    Last edited by coolguy4; 02-11-2018 at 04:23 PM.



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    Re: What exactly is a “nonflammable” refrigerant?

    .

    Like you I did not know that so I looked up the definition and to be classed
    as Nonflammable it does not burn or does not burn easily so by definition
    Non-flammables could be made to burn if you wanted them to.

    So I would say a prerequisite to flammable would be in air at ambient temp.

    I know the flash point at 21degC is important on flammables so maybe that is the temp
    that things are measured at. 1 bar atmospheric pressure and at 21dagC it won't burn??

    Rob

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    Re: What exactly is a “nonflammable” refrigerant?

    Quote Originally Posted by Rob White View Post
    .

    Like you I did not know that so I looked up the definition and to be classed
    as Nonflammable it does not burn or does not burn easily so by definition
    Non-flammables could be made to burn if you wanted them to.

    So I would say a prerequisite to flammable would be in air at ambient temp.

    I know the flash point at 21degC is important on flammables so maybe that is the temp
    that things are measured at. 1 bar atmospheric pressure and at 21dagC it won't burn??

    Rob

    .
    Interesting, thank you. So could a “non flammable” refrigerant support combustion then?

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    Re: What exactly is a “nonflammable” refrigerant?

    .

    It would appear so by your experiment.
    It didn't have any oil in did it? Was is new unused?
    I know oil burns so if it was old then it might have oil?

    Rob

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    Re: What exactly is a “nonflammable” refrigerant?

    Quote Originally Posted by Rob White View Post
    .

    It would appear so by your experiment.
    It didn't have any oil in did it? Was is new unused?
    I know oil burns so if it was old then it might have oil?

    Rob

    .
    The refrigerant I used was new, and it was pure R134A with no oil or additives.

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    Re: What exactly is a “nonflammable” refrigerant?

    Reading the MSDS for R134a it didn't say that it burn in high temperatures but that it could decompose.

    If you had a container of R134a and opened it then putting a flame at the opening would not cause ignition of the R134a. Therefore it is non-flammable.

    Spraying R134a into a gaseous flame will cause decomposition due to the chemical reaction between the flame and the R134a.

    Bear in mind that petrol (gasoline) is non-flammable but only if you can get your flame through the petrol vapour to the liquid.
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    Re: What exactly is a “nonflammable” refrigerant?

    Thanks for the great responses, very informative. So here’s a question: Couldn’t R410A burn if it leaks out as a vapor? My thought is that since it’s a 50/50 mix of R32 and R125, and the R32 is higher pressure and would leak out first, couldn’t the high concentration of R32 be flammable?

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    Re: What exactly is a “nonflammable” refrigerant?

    It surely depends on where it leaks into to enable a high concentration to form.
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    Re: What exactly is a “nonflammable” refrigerant?

    From DuPont’s R134A MSDS:

    “Contact of welding or soldering torch flame with high concentrations of refrigerant can result in visible changes in the size and color of torch flames. This flame effect will only occur in concentrations of product well above the recommended exposure limit, therefore stop all work and ventilate to disperse refrigerant vapors from the work area before using any open flames.HFC-134a is not flammable in air at temperatures up to 100 deg. C (212 deg. F) at atmospheric pressure. However, mixtures of HFC-134a with high concentrations of air at elevated pressure and/or temperature can become combustible in the presence of an ignition source. HFC-134a can also become combustible in an oxygen enriched environment (oxygen concentrations greater than that in air). Whether a mixture containing HFC-134a and air, or HFC-134a in an oxygen enriched atmosphere become combustible depends on the inter-relationship of 1) the temperature 2) the pressure, and 3) the proportion of oxygen in the mixture. In general, HFC-134a should not be allowed to exist with air above atmospheric pressure or at high temperatures; or in an oxygen enriched environment. For example HFC-134a should NOT be mixed with air under pressure for leak testing or other purposes. Experimental data have also been reported which indicate combustibility of HFC-134a in the presence of certain concentrations of chlorine.”

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    Re: What exactly is a “nonflammable” refrigerant?

    ^^post #9 ^^
    Can't argue with that from the manufacturer, however in the normal run of the mill usage of the refrigerant you will not come across a flammable state with R134a.

    If you plan to fill a room with R134a and then light a burner you must expect to receive everything that comes from doing such an irresponsible deed.
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    Re: What exactly is a “nonflammable” refrigerant?

    Quote Originally Posted by Brian_UK View Post
    ^^post #9 ^^
    Can't argue with that from the manufacturer, however in the normal run of the mill usage of the refrigerant you will not come across a flammable state with R134a.

    If you plan to fill a room with R134a and then light a burner you must expect to receive everything that comes from doing such an irresponsible deed.
    I agree. R134A won’t be ignited by a spark, but from what I saw, it can burn if an open flame is held to it.

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    Re: What exactly is a “nonflammable” refrigerant?

    Quote Originally Posted by coolguy4 View Post
    I agree. R134A won’t be ignited by a spark, but from what I saw, it can burn if an open flame is held to it.
    So will most chemicals when you put a flame on them. Burn or decompose is to be expected in that situation.
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    Re: What exactly is a “nonflammable” refrigerant?

    Quote Originally Posted by Brian_UK View Post
    So will most chemicals when you put a flame on them. Burn or decompose is to be expected in that situation.
    R12 would put the flame out.

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    Re: What exactly is a “nonflammable” refrigerant?

    So will petrol (gasolene).

    The decomposition of R12 due to high temperature (flame) will create hazardous chemicals.

    This subject is endless by the way.
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