põlemispunkt

Põlemispunkt, or flash point in English, is the lowest temperature at which a liquid can vaporize to form an ignitable mixture in air. At this temperature, a sufficient concentration of flammable vapor is produced by the liquid to ignite when an ignition source is present. The flash point is an important measure for the safe handling and storage of flammable liquids.

The flash point is not the temperature at which the liquid itself will burn. The substance needs to reach its autoignition temperature, which is higher than the flash point, to sustain combustion without an external ignition source. Different substances have different flash points, which are determined by their chemical composition and volatility. For example, highly volatile liquids like gasoline have very low flash points, making them highly flammable. Less volatile liquids like diesel fuel have higher flash points.

Flash point is typically determined using standardized testing methods. These methods involve heating a sample of the liquid in a controlled environment and periodically exposing it to a small flame. The lowest temperature at which a flash is observed is recorded as the flash point. This value is crucial for classifying hazardous materials and determining appropriate safety precautions, such as ventilation requirements and the type of electrical equipment that can be used in areas where the substance is stored or handled. It is a key parameter in fire safety regulations and transportation guidelines for flammable liquids.