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  1. #1
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    R600a calculation



    I need a boffin or techy.
    Theroretical but I would like to find the answer ,if there was a leak (say 100rms) it vapourises/expands,then mixes with air,it needs approx 1 part isobutane vapour to 9 parts air for flammability, so the 100 grams expands as a voupour mixes with air at a rate of 1 to 10,:
    Wondered what would be the cubic size of this complete mixture would be.
    So if 100 gram leak takes place in a room 10 meters x 5 meters would it fill it (as a flammable mixture) over flow from the room
    Any help would be of great interest.

    Gas Data
    Atomic Weight
    58.124
    Boiling Temp.
    -12
    Vapour Pressure
    (psia) @ 15°
    38
    Critical Temp. (°C)
    135
    Cond. Temp. at
    26 bar abs (°C)
    114



    I am sure I have worked this out in the past but sadly the grey matter is slowly turning to sludge.
    I know he explosion/flammable limits are between 1.5% and 15%approx mixture with air
    Thanks
    BG
    Last edited by spimps; 25-01-2012 at 06:26 PM. Reason: adjust figures


    “Life is like riding a bicycle. To keep your balance you must keep moving” Einstein

  2. #2
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    Re: R600a calculation

    Sorry ,meant to put this in refrigerants, if a mold would like to move it please.
    Like I said grey matter and sludge
    “Life is like riding a bicycle. To keep your balance you must keep moving” Einstein

  3. #3
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    Re: R600a calculation

    I can not answer your question directly but I know that hydrocarbons can be flammable at as lo as 0.2%

  4. #4
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    Re: R600a calculation

    Thanks to National refigerants:
    SPECIFIC GRAVITY (H2O=1.00):
    0.564
    BOILING RANGE:
    10.9 Deg. F
    PRESENT VOLATILE BY VOLUME:
    100%
    VAPOR PRESSURE @ 70 Deg. F:
    31 psig
    VAPOR DENSITY (air = 1.00):
    2.006
    EVAPORATION RATE:
    > 1 (Ethyl Ether = 1.0)

    FLAMMABLE PROPERTIES

    FLASH POINT (METHOD):
    -117 F (Open Cup)

    UPPER EXPLOSIVE LIMIT (vol.) gas in air):
    8.4%

    LOWER EXPLOSIVE LIMIT (vol.) gas in air):
    1.8%

    This might help someone,possibly connected to the 31psi to condense to liquid.

    “Life is like riding a bicycle. To keep your balance you must keep moving” Einstein

  5. #5
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    Re: R600a calculation

    All the way back to Charle's, Boyle's, Avagadro's, Stochiometrics and well a few others.

    molecular weight of Isobutane 58.12. so 100 grams is 100/58.12=1.72 gm-Moles; its density at STP is 2.6 kg/m^3. So your 100 Grams occupies More or Less 0.038 m^3. This represents about 6 Bic Lighters....

    The lower explosive limit says you need a space smaller than 100/1.8*0.038+0.0308=2.14 m^3 for there to be a combustible mixture, as long as the Air and the ISO are well mixed. Or your 10 by 5 meter room would need to be less than 5 cm high.....Put another way: To reach the LFL in a room 10 by 5 by 4 meters, you need almost 9.5 Kg of Isobutane.

  6. #6
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    Re: R600a calculation

    Excellent and informative explanatiion,many thanks.
    It's about getting a perspective on the amount needed to cause a problem,very helpful.
    “Life is like riding a bicycle. To keep your balance you must keep moving” Einstein

  7. #7
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    Re: R600a calculation

    Sorry my .2 was a missunderead 2 %

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