E2658-LEL
Rev 11.03.2022
Acetylene
A colorless flammable gas, lighter than air. Mixtures with air are explosive. It results from
the interaction of calcium carbide with water. In industrial production, acetylene is mainly
manufactured by the pyrolysis of light hydrocarbons.
Acetylene is widely used for welding and cutting of metals. The usage of acetylene as a
feedstock in the chemical industry declines due to cost and environmental considerations.
Synonyms/Trade Names: Ethine, Ethyne.
Chemical formula
HC≡CH
Molar weight
26
Relative gas density (to air)
0.90
Conversion
1 ppm = 1.06 mg/m
3
Boiling point
-84 °C
Low explosive limit (LEL), % vol. in air
2.3* (2.5**)
Upper explosive limit (UEL), % vol. in air
100
Odor
Odorless or with a faint ethereal smell if pure. The
commercial-grade may have a garlic-like smell due to
impurities.
Hazards
Highly flammable.
Gas/air mixtures are explosive. Forms explosive
acetylide compounds with copper, mercury, silver &
brasses (containing more than 66% copper).
Asphyxiant. Non-toxic, but, when generated from calcium
carbide, it can contain toxic impurities such as traces of
phosphine and arsine.
Exposure limits
(NIOSH)
REL C
2662 mg/m
3
/2500 ppm
4
