What is a backfire in torch operations?

In the context of torch operations, a backfire refers to the pop sound that occurs when the flame goes out suddenly while operating a torch. This phenomenon can happen due to several reasons, such as a sudden change in fuel flow or a momentary disruption in the combustion process. The audible pop is a crucial indicator for operators to recognize that the torch has malfunctioned or that there may have been an interruption in fuel delivery.

Understanding the nature of a backfire is important for torches, as it helps operators identify issues with the torch operation that might require immediate attention, ensuring safety during torch work. In contrast, the other options describe different scenarios or sounds that do not accurately capture the specific phenomenon of a backfire in torch operations.