What does the term 'Lag of Ignition' refer to?

The term 'Lag of Ignition' specifically refers to the time it takes for a gas to ignite after it comes into contact with an ignition source. This concept is essential in understanding combustion processes, as it highlights the delay that can occur before a fuel mixture ignites when exposed to adequate heat or a spark. This lag can vary depending on factors such as the properties of the gas, its mixture with air, and the nature of the ignition source.

A longer ignition lag can pose safety risks in environments where gas leakage might occur, as it may lead to an accumulation of flammable gas before ignition takes place. Hence, knowing the lag time is crucial for implementing safety measures and ensuring proper ventilation and monitoring to prevent dangerous conditions.

The other options do not accurately describe this phenomenon: cooling down after ignition, the duration of an explosion, or gas concentration equalization do not represent the process of ignition itself. Understanding the lag of ignition is vital for professionals working with flammable gases in various industries.