Vonkpunt

Vonkpunt is a term used in chemistry and safety science to denote the lowest temperature at which a liquid’s vapors can form an ignitable mixture with air in the presence of an ignition source. In Dutch usage it is commonly equated with the English term “flash point.” The vonkpunt is a critical parameter for assessing flammability and guiding the safe handling, storage, and transport of liquids such as fuels, solvents, and chemicals. A lower vonkpunt indicates a higher risk of ignition at ambient temperatures.

The vonkpunt is distinct from the autoignition temperature, which is the temperature at which a substance will ignite spontaneously in air without an external spark or flame. The flash point requires an ignition source, whereas autoignition does not.

Measurement of the vonkpunt is performed under standardized conditions at or near atmospheric pressure. Two common test categories are open cup and closed cup methods; open cup tests generally yield lower values because vapors escape more readily, while closed cup tests are more protective and widely used for safety labeling. International standards (ISO and ASTM) describe procedures and equipment for determining the flash point, including closed cup devices such as Pensky-Martens and Setaflash testers.

Applications of vonkpunt data include classification of liquids as flammable or combustible, informing labeling and hazard communication, and guiding storage, handling, and transport regulations. It also helps assess compatibility with ignition sources and with other materials. Some substances have very low or very high flash points, while a few may have no measurable flash point under standard testing conditions.