The lowest temperature at which a liquid will give off sufficient vapor to be ignited in air is called the

The lowest temperature at which a liquid will give off sufficient vapor to be ignited in air is called the

• A. Autoignition Temperature
• B. Lower Flammable Limit
• C. Flash Point
• D. Upper Flammable Limit

Answer: (C)

The concept being tested is the flash point: the lowest temperature at which a liquid releases enough vapor to form an ignitable mixture with air when an ignition source is present. At this temperature, a flame or spark can ignite the vapor. Below it, there isn’t enough vapor to sustain ignition. This differs from the autoignition temperature, which is the temperature at which the material will ignite without any external flame or spark. It also differs from the lower and upper flammable limits, which describe the concentration range of vapor in air that can ignite (not the temperature). In short, the flash point is about the temperature at which vapor formation becomes sufficient for ignition when exposed to a flame or spark.

The concept being tested is the flash point: the lowest temperature at which a liquid releases enough vapor to form an ignitable mixture with air when an ignition source is present. At this temperature, a flame or spark can ignite the vapor. Below it, there isn’t enough vapor to sustain ignition. This differs from the autoignition temperature, which is the temperature at which the material will ignite without any external flame or spark. It also differs from the lower and upper flammable limits, which describe the concentration range of vapor in air that can ignite (not the temperature). In short, the flash point is about the temperature at which vapor formation becomes sufficient for ignition when exposed to a flame or spark.