Smoke extract fans — outside hazardous area, motor protected in clean air

Fans for mounting outside the hazardous area are smoke extraction equipment in which the electric motor is located and operates in clean air — outside the smoke stream — while the rotor extracts hot gases from the fire zone through ductwork. An extended shaft or a separate motor cooling duct ensures thermal and chemical separation of the motor from the smoke environment.

This construction offers important advantages over inside hazardous area mounting: the motor is not exposed to extreme temperatures, corrosive smoke and combustion gases, which reduces motor construction requirements and sometimes allows the use of standard AC motors (where the installation ensures sufficient distance from the smoke). Certification remains mandatory to EN 12101-3, but a wider range of models is available.

Preferred in commercial and office buildings where plant rooms allow locating the fan away from the protected zone, shopping centres with layouts permitting moderate-length smoke ducts, hotels and apartment buildings with smoke control systems on corridors and stairwells, hospitals and any building where the designer can ensure motor placement outside the classified smoke zone.

From the designer's perspective, the choice between "inside" and "outside hazardous area" is made at the design stage — after smoke duct routes are established and fan placement is determined from architectural considerations. Both solutions are accepted by EN 12101 and the applicable building regulations, subject to appropriate certification.

Documents to verify: identical to the "inside hazardous area" category — notified body certificate, EN 12101-3 performance declaration, CE marking, F300/F400 classification and duration (60/120 minutes).

👉 Smoke extract fans inside hazardous area — when motor cannot be separated from smoke 👉 ATEX roof fans — for rooftops with explosion risk