What is the explosive mixture of acetylene and air?

• A. 2.5 - 80%
• B. 1 - 5%
• C. 10 - 20%
• D. 50 - 90%

Answer: (A)

Acetylene in air has a flammable range—the concentrations at which ignition can occur. For acetylene, that range is roughly 2.5% to about 80% acetylene by volume in air. Below about 2.5%, the mixture is too lean to ignite; above about 80%, there isn’t enough oxygen to sustain combustion. So the explosive mix is within 2.5% to 80% acetylene in air. The other ranges are outside this window.