ATEX is derived from the French abbreviation for ATmosphères EXplosives. Fans are also sometimes used in potentially explosive atmospheres. Due to the high necessary safety requirements, this application and the construction design of the fans are subject to strict normative specifications and regulations. Fans for use in explosive atmospheres are always project-dependent and must be considered individually. The ATEX zones and requirements for fans and radial fan impellers in ATEX applications are explained in the following chapter.