Gas Fitter Practice Test

What type of flame results from mixing primary air with gas before ignition and appears blue?

1. A Bunsen flame

2. A luminous flame

3. A gas rich flame

4. An air rich flame

The correct answer is: A Bunsen flame

The type of flame that results from mixing primary air with gas before ignition and appears blue is known as a Bunsen flame. This flame is characterized by its clean, blue appearance, which indicates a complete combustion process. In a Bunsen flame, the primary air is introduced in a manner that promotes the thorough mixing of gas and air before ignition, resulting in a flame that burns more efficiently and produces less soot compared to flames that lack sufficient air. The blue color signifies that there is enough oxygen present for complete combustion, meaning that the gas burns hotter and cleaner. This is crucial in applications requiring precise heat and efficiency, such as in laboratories or workshops where a controlled flame is necessary. The other types of flames, such as luminous or gas-rich flames, typically indicate incomplete combustion, producing yellow or orange flames associated with soot formation. An air-rich flame would suggest an excess of air leading to a cooler temperature, which also impacts efficiency and the characteristics of the flame. The Bunsen flame's characteristics make it ideal for tasks needing specific temperature control and minimal byproducts.