Which flame type is the hottest of all flames?

• A. Carburizing flame
• B. Oxidizing flame
• C. Neutral flame
• D. None of the above

Answer: (B)

In oxy-fuel flame theory, flame temperature rises with the amount of oxidizer driving the combustion. An oxidizing flame has extra oxygen, which makes the reaction proceed more completely and rapidly, releasing more heat per unit of fuel. That extra heat pushes the flame temperature higher than the other common flame types. A neutral flame is balanced between fuel and oxygen, delivering steady heat but not as hot as the oxidizing flame. A carburizing flame has excess fuel and tends to burn with incomplete combustion, creating soot and reducing the effective heat delivered. So, the hottest flame is the oxidizing flame.