syttyvyyslämpötilan

Syttyvyyslämpötila, also known as flash point, is the lowest temperature at which a volatile material can vaporize to form an ignitable mixture in air. At this temperature, the vapor above the liquid is sufficient to ignite when an external ignition source, such as a spark or flame, is present. However, the vapor will not continue to burn on its own after the ignition source is removed.

The concept of flash point is crucial for assessing the flammability hazards of liquids and for determining safe storage, handling, and transportation procedures. Liquids with lower flash points are more volatile and pose a greater fire risk. For example, gasoline has a much lower flash point than diesel fuel, making it more prone to ignition.

Flash point is typically determined using standardized testing methods, such as the Pensky-Martens closed-cup method or the Tag closed-cup method. These tests involve carefully heating a sample of the liquid while intermittently applying a small flame to the vapor space above it. The temperature at which the first flash is observed is recorded as the flash point.

It is important to distinguish flash point from autoignition temperature, which is the temperature at which a substance will spontaneously ignite in a normal atmosphere without an external ignition source. While flash point indicates the temperature at which a flammable mixture can be *ignited*, autoignition temperature indicates the temperature at which ignition occurs *spontaneously*.