Reversible Axial Fans for Industrial Ventilation and Safety Compliance

Reversible axial fans are essential for versatile airflow management and safety compliance in complex industrial environments.

CBI Group leverages over 60 years of engineering expertise to design and manufacture high-performance axial fans that seamlessly switch between supply and extraction modes. This bidirectional capability allows operators to manage airflow dynamically, whether responding to process requirements, pressure balancing needs, or emergency smoke control scenarios.

Unlike installations that require two separate units for supply and extraction, reversible axial fans provide a space-saving and cost-effective alternative. For tunnels, warehouses, factories and large infrastructure projects, this translates into reduced installation footprint, simplified electrical architecture and lower lifecycle costs.

CBI’s reversible axial series is engineered to meet demanding industrial requirements with:

• maximum pressure up to 1,800 Pa;

• airflow rates up to 480,000 m³/h;

• seven available sizes with impeller diameters up to 2,240 mm;

• extruded airfoil blades with adjustable pitch angle.

This combination of aerodynamic performance and structural robustness makes the EFA series suitable for heavy-duty industrial ventilation and safety-critical applications.

The engineering of reversible blade technology

A reversible axial fan provides bidirectional airflow by inverting its rotation.
While the concept may appear straightforward, achieving high efficiency in both directions requires advanced aerodynamic engineering. Standard asymmetrical blade profiles are optimised for one direction only; when rotation is reversed, efficiency drops significantly and turbulence increases.

CBI’s reversible axial configurations - available for GAV, GAX series - are engineered with specialised airfoil blades designed to maintain aerodynamic stability in both rotational directions. Developed through CFD simulations and validated via structural FEM analysis, these blades maintain stable aerodynamic behaviour in both rotational directions, ensuring mechanical reliability during rapid switches.

Key engineering features include:

• extruded airfoil blade profiles for structural precision and repeatability;

• adjustable blade pitch angle to fine-tune performance on site;

• impeller diameters reaching 2,240 mm;

• pressure stability even during rapid direction switching;

• vibration-controlled mechanical design to protect bearings and motor assemblies.

Maintaining aerodynamic efficiency during inversion is critical not only for performance, but also for motor protection and system reliability. In applications such as tunnel ventilation or large industrial plants, where airflow direction may change in emergency scenarios, this stability becomes a safety requirement, not merely a performance parameter.

Reliability with CBI expertise

Maintaining long-term performance requires more than just high-quality hardware; it demands dedicated support, and CBI delivers the only full 360° lifecycle management in Italy: design, production, service, revamping and spares all in-house. 

Our Spares & Service Division provides specialised assistance across every phase of the industrial fan lifecycle, ensuring operational continuity even in demanding conditions.

Services include:

• professional installation and commissioning with full functional testing;

• periodic and extraordinary maintenance, including frequency vibration analysis for predictive diagnostics;

• onsite aeraulic testing to verify real operating conditions and performance deviations;

• predictive analysis based on historical data and advanced modelling;

• onsite revamping to adapt performance to plant modifications;

• complete factory revamping with full disassembly, inspection and component replacement;

• reverse engineering through 3D scanning to replicate or improve discontinued components;

• immediate availability of original or perfectly interchangeable spare parts.

Thanks to an extensive technical database and in-house R&D capabilities, CBI can upgrade legacy installations, apply the latest mechanical improvements and extend operational lifespan well beyond original expectations.

This fully integrated structure is managed internally across certified facilities operating under ISO 9001 and ISO 14001 standards, with ATEX compliance available when required; global on-site interventions ensure minimal downtime worldwide.

The result is faster intervention, reduced downtime and coordinated operations aligned with plant management.