flammableCombustibles

Although Interscan is in the toxic gas detection business, many of our customers are also involved with flammable and combustible compounds, so we are pleased to provide the following information.

Flammable and combustible chemicals are those that evaporate fast enough to generate sufficient vapor to ignite in the presence of an ignition source. The temperature at which this can occur is the chemical's flash point.

In addition, flammable and combustible chemicals are those that can react with oxidizers, to cause a fire or explosion. Combustible materials will generate sufficient vapors at or above 100°F (37.8°C). Flammable chemicals will generate sufficient vapors at temperatures below 100°F (37.8°C).

Material Safety Data Sheets may also list a chemical's auto-ignition temperature, which is the lowest temperature at which there is enough heat energy to ignite vapors spontaneously.

Other important characteristics of flammable and combustible chemicals are their explosive limits. The Lower Explosive Limit (LEL or lower flammable limit) is the lowest concentration of the substance in air that will produce a flash of fire when an ignition source is present. The Upper Explosive Limit (UEL or upper flammable limit) is the highest concentration of the substance in air that will produce a flash of fire when an ignition source is present.

At higher concentrations than the UEL, the mixture is too rich to burn. At concentrations lower than the LEL, the mixture is too lean to burn. Note that for flammable chemicals that are also toxic, concentrations at which the flammability is a hazard are usually well above the toxicity hazard concentrations.

Table of LEL's/UEL's

 

GasLEL (% by volume)UEL (% by volume)
Acetone2.612.8
Acetylene2.5100
Acrolein2.831
Acrylonitrile317
Allene (propadiene)1.511.5
Ammonia1528
Benzene1.37.9
1,3-Butadiene212
Butane1.68.4
n-Butanol1.411.2
1-Butene1.610
Cis-2-Butene1.79.7
Trans-2-Butene1.79.7
Butyl Acetate1.77.6
Carbon Disulfide1.350
Carbon Monoxide12.574
Carbonyl Sulfide1229
Chlorotrifluoroethylene8.438.7
Cumene0.96.5
Cyanogen6.632
Cyclohexane1.37.8
Cyclopropane2.410.4
Decaborane0.2---
Deuterium4.975
Diborane0.888
Dichlorosilane4.198.8
Diethylbenzene0.8---
Diethyl Ether1.936
1,1-Difluoro-1-Chloroethane914.8
1,1-Difluoroethane5.117.1
1,1-Difluoroethylene5.521.3
Dimethylamine2.814.4
Dimethyl Ether3.427
2,2-Dimethylpropane1.47.5
Dimethyl Sulfide2.220
Ethane312.4
Ethanol3.319
Ethyl Acetate2.211
Ethyl Amine3.514
Ethyl Benzene0.86.7
Ethyl Chloride3.815.4
Ethylene2.736
Ethylene Oxide3100
Gasoline1.27.1
Heptane1.16.7
Hexane1.27.4
Hydrazine2.998
Hydrogen475
Hydrogen Cyanide5.640
Hydrogen Sulfide444
Isobutane1.88.4
Isobutylene1.89.6
Isopropanol2.212.7
Methane515
Methanol6.736
Methylacetylene1.711.7
Methyl Bromide1015
3-Methyl-1-Butene1.59.1
Methyl Butyl Ketone1.28
Methyl Cellosolve1.814
Methyl Chloride8.117.4
Methyl Ethyl Ketone1.411.4
Methyl Mercaptan3.921.8
Methyl Vinyl Ether2.639
Monoethylamine3.514
Monomethylamine4.920.7
Monomethylhydrazine2.592
Nickel Carbonyl2---
Pentane1.47.8
Picoline1.4---
Propane2.19.5
Propionaldehyde2.917
Propylene2.411
Propylene Oxide2.837
Styrene0.96.8
Tetrafluoroethylene443
Tetrahydrofuran211.8
Toluene1.17.1
Trichloroethylene810.5
Triethylene Amine1.28
Trimethylamine211.6
Turpentine0.7---
Unsymmetrical dimethylhydrazine295
Vinyl Acetate2.613.4
Vinyl Bromide915
Vinyl Chloride3.633
Vinyl Fluoride2.621.7
Xylene0.97

The flammable liquids of most concern in industry and laboratories are those that have flash points below room temperature. These include...

SolventFlash Point (° C) Flash Point  [° F]
Acetone-17.8[0]
Benzene-11[12.2]
Carbon disulfide-29[-20.2]
Ethanol13[55.4]
Ethyl acetate1[33.8]
Ethyl ether-45[-49]
Hexane-18[-0.4]
Toluene9.5[49.1]
Xylene
(above room temperature—but close enough)
29[84.2]

Data obtained from various sources, presumed to be reliable, for reference only. In any critical application, double check all parameters, including flammable properties!