Helios Fans RDD 355/4 Ex

The Helios RDD 355/4 Ex is a robust explosion-proof centrifugal roof fan designed for horizontal discharge applications in hazardous environments. Certified to ATEX standards, it ensures safe operation in potentially explosive atmospheres while delivering high performance and energy efficiency.

Its housing is constructed from corrosion-resistant, seawater-grade aluminum and features integrated intrusion protection for added durability. The motor support and base plate are made of galvanized steel, paired with an aerodynamic inlet nozzle crafted from aluminum. The base plate is equipped with threaded screws for secure attachment of intake-side accessories and complies with DIN 24155 (sheet 3) mounting standards. A discharge-side protective grille is included as standard, adhering to DIN EN ISO 13857 safety requirements.

This model is fitted with a backward-curved centrifugal impeller made from aluminum, dynamically balanced to DIN ISO 1940 – 1 for quiet, low-vibration operation.

Power is provided by a totally enclosed, speed-controllable three-phase external rotor motor with IP44 protection. The motor is ball-bearing mounted with built-in moisture protection, ensuring long-lasting, maintenance-free performance. It is also radio interference suppressed and fully compliant with ATEX explosion-proof requirements.

Ideal for industrial rooftop installations where explosion protection is critical, the Helios RDD 355/4 Ex delivers both safety and high airflow efficiency.