Explosion And Flammability Concentration Limits

The Flammable Range (additionally known as Explosive Range) is the attention range of a fuel or vapor with the intention to burn (or explode) if an ignition source is introduced.

Three primary requirements should be met for explosion to take vicinity:

  • flammable substance – gasoline
  • oxidizer – oxygen or air
  • source of ignition – spark or excessive warmness
  • Below the explosive or flammable range the combination is simply too lean to burn and above the top explosive or flammable restrict the aggregate is too wealthy to burn. The limits are commonly called the “Lower Explosive or Flammable Limit” (LEL/LFL) and the “Upper Explosive or Flammable Limit” (UEL/UFL).

    The lower and top explosion attention limits for a few generally used gases are indicated within the desk below. Some of the gases are typically used as fuel in combustion processes.

    Note! The limits indicated are for gasoline and air at 20oC and atmospheric pressure.Fuel Gas”Lower Explosive or Flammable Limit”


    (% via extent of air)“Upper Explosive or Flammable Limit”


    (% by extent of air)Acetaldehyde four 60Acetic acid four 19.9Acetone 2.6 12.8Acetonitrile 3 16Acetyl chloride 7.3 19Acetylene explos info 2.5 100Acrolein 2.8 31Acrylic acid 2.4 8Acrylonitrile 3.zero 17Allyl chloride 2.9 11.1Allyll alcohol 2.5 18Alyllamine 2.2 22Ammonia 15 28Aniline 1.3 11Arsine 5.1 78Benzene 1.2 7.8Biphenyl zero.6 five.8Bromobuthane (1-Bromobuthane) 2.6 6.6Bromoethane 6.8 8Bromoethene nine 15Butadiene (1,3-Butadiene) 2.zero 12Butanal 1.9 12.5Butane (n-Butane) 1.86 eight.41Butanoic acid 2 10Butyl acetate 1.7 7.6Butyl alcohol, Butanol 1 11Butyl formate 1.7 eight.2Butyl methyl ketone 1 8Butylamine 1.7 9.8Butylbenzene zero.5 5.8Butylene 1.ninety eight 9.65Butyll acrylate 1.nine 9.9Carbon disulfide 1.three 50Carbon monoxide 12 75Carbon oxysulfide 12 29Chlorobenzene 1.3 9.6Chloroethane 3.eight 15.4Cyanogen 6.zero 42.6Cyclobutane 1.eight 11.1Cycloheptane 1.1 6.7Cyclohexane 1.three 8Cyclohexanol 1 9Cyclohexanone 1 9Cyclopropane 2.4 10.4Decane 0.eight five.4Diacetone alcohol 1.eight 6.9Diborane zero.eight 88Dibutylamine 1.1 6Dichloroethane (1,1-Dichloroethane) 6 11Diesel fuel 0.6 7.5Diethanolamine 2 13Diethyl ether 1.nine 36Diethylamine 2 13Diethylether 1.nine 48Diisobutyl ketone 1 6Diisopropyl ether 1 21Dimethyl sulphoxide three 42Epichlorohydrin four 21Ethane 3 12.4Ethyl acetate 2 12Ethyl acrylate 1.four 14Ethyl alcohol, Ethanol three.three 19Ethyl chloride 3.8 15.4Ethyl nitrite 4 50Ethyl propyl ether 1.7 9Ethyl vinyl ether 1.7 28Ethylamine 3.5 14Ethylbenzene 1.zero 7.1Ethylcyclobutane 1.2 7.7Ethylene 2.seventy five 28.6Ethylene oxide three 100Etylene glycol 3 22Fluoroethene 2.6 21.7Formaldehyde 7 73Formic acid 18 57Fuel Oil – No.1 zero.7 5Furan 2 14Furfural 2 19Gasoline 1.four 7.6Glycerol three 19Heptane 1.zero 6.7Heptane (n-Heptane) 1.0 6.0Hexane 1.1 7.5Hexane (n-Hexane) 1.25 7.0Hydrazine 5 100Hydrogen four 75Hydrogen 6 40Hydrogen sulfide four.three 46Isobutanal 1.6 10.6Isobutane 1.80 8.44Isobutene 1.eight nine.0Isobutyl alcohol 2 11Isooctane zero.seventy nine 5.94Isopentane 1.32 nine.16Isophorone 1 4Isopropyl alcohol, Isopropanol 2 12Isopropylbenzene 0.9 6.5Kerosene Jet A-1 0.7 5Mesityl oxide 1.4 7.2Methacrylic acid 1.6 eight.8Methane four.4 sixteen.4Methylamine four.9 20.7Methyl acetate three 16Methyl alcohol, Methanol 6.7 36Methyl acrylate 2.8 25Methyl chloride 10.7 17.4Methyl ethyl Ketone 1.eight 10Methyl formate 4.5 23Methylhydrazine 2.5 92Methyl isocyanate five.3 26Mineral spirits 0.7 6.5Naphtalene zero.nine five.9Naphthalene 0.9 5.9Neohexane 1.19 7.58Neopentane 1.38 7.22Nitrobenzene 2 9Nitroethane three.4 17Nitromethane 7.3 22.2Nonane 0.eight 2.9Octane (n-Octane) 1.0 7Oxirane three 100Paraformaldehyde 7 73Pentane (n-Pentane) 1.four 7.8Pentene (n-Pentene) 1.65 7.7Pentyl acetat 1.1 7.5Pentylamine 2.2 22Phenol 1.eight 8.6Piperidine 1 10Propane 2.1 10.1Propanoic acid 2.nine 12.1Propene 2 11.1Propyl acetate 2 8Propylamine 2 10.4Propylbenzene 0.eight 6Propyl nitrate 2 100Propylene 2.0 11.1Propylene oxide 2.3 36Propyne 2.1 12.5Pyridine 2 12Silane 1.5 98Styrene 1.1 6.1Tetrafluoroethene 10 50Tetrahydrofuran 2 12Toluene 1.1 7.1Trichloroethylene 13 90Triethylene glycol 0.9 nine.2Triptane 1.08 6.69Trimethylamine 2 11.6Turpentine 0.8Vinyl acetate 2.6 13.4Vinyl butanoate 1.4 eight.8Vinyl chloride 3.6 33o-Xylene zero.nine 6.7m-Xylene 1.1 7p-Xylene 1.1 7

    It is vital that regions that shop flammable gases are well ventilated. When designing ventilation structures be aware about the precise gravity of the real gasoline. The gasoline aggregate from a leakage will not be homogeneous and lighter gases concentrates along the ceiling. Heavy gases concentrates along the ground.

    Ventilation, natural or mechanical, have to be sufficient to restrict the concentration of flammable gases or vapors to a most stage of 25% in their “Lower Explosive or Flammable Limit” (LEL/LFL).

    • Minimum ventilation required: 1 cfm/ft2 (20 m3/h m2)
    • Recommended air flow: 2 cfm/ft2 (40 m3/h m2) or 12 air changes per hour – 1/2 the air supplied and exhausted near the ceiling and half the air furnished and exhausted near the ground

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