Category 2D / 3D fans for zones 21 / 22

In cases where an explosive atmosphere exists as a result of flammable dust, increased risks due to electrostatic charging and the build-up of flammable layers must be taken into account.

The fan casing should be easy to clean, possibly via a cleaning opening, and must be equipped with dust-repellent impellers. In the area of the shaft seal, risks arising from frictional heat caused by build-up must be taken into account. On the drive side, special dust motors are used whose maximum surface temperature is suitable for the flammable medium.

Zone 20 applications (frequent or constant flammable dusty atmosphere) cannot be covered with a fan. A flame barrier required for this would be clogged too quickly by dust-containing medium.