E2630-LEL
Rev 23.03.2021
Butane
A colorless flammable gas that is heavier than air. The term “butane” is used for any of two
structural isomers (n-butane or iso-butane, with unbranched and branched-chain
respectively) or for their mixture. Occurs in light petroleum fractions.
Butane is used mainly as a fuel and as a feedstock in organic synthesis. It is applied also
as a propellant in aerosol sprays and may be used as an ozone-friendly refrigerant.
Mixtures of butane with propane and other hydrocarbons are referred to as LPG (liquefied
petroleum gas).
Chemical formula
n-butane
CH
3
CH
2
CH
2
CH
3
iso-butane
CH
3
CH(CH
3
)CH
3
Molar weight
58
Relative gas density (to air)
2.0
Conversion
1 ppm = 2.38 mg/m
3
Boiling point
-0.56 °C
−11.7 °C
Low explosive limit (LEL), % vol. in air
1.4* (1.6**)
1.5* (1.8**)
Upper explosive limit (UEL), % vol. in air
8.4
9.6
Odor
Gasoline-like odor
Hazards
Highly flammable.
Inhalation of butane can cause euphoria, drowsiness,
narcosis, asphyxia, cardiac arrhythmia, fluctuations in
blood pressure, and temporary memory loss, when
abused directly from a highly pressurized container, and
can result in death from asphyxiation and ventricular
fibrillation.
Exposure
limits
(NIOSH)
TWA
1900 mg/m
3
/800 ppm
Not established
4
