DIN EN 1710 applies to the design of fans in equipment group I, while DIN EN 14986 is the authoritative document for equipment group II. "Category 3 fans must not generate an effective ignition source during normal operation. Category 2 fans must meet the requirements for category 3 fans and must not produce an effective ignition source in the event of an expected malfunction. Category 1 fans shall meet the requirements for 2 and 3 and shall not produce an effective ignition source during infrequent malfunctions." The design measures in the above standards must be implemented for this purpose.
Fans are divided in a
- inner zone = flowing medium and
- outer zone = environment of the fan.
When designing the fans, care must be taken to ensure that zone mixing cannot occur.
At the same time, when designing the product, all components of the assembly must be designed in accordance with the ATEX zone assessment provided by the equipment manufacturer.