Centrifugal Fan Direction: Understanding Fan Rotation and Performance

What is centrifugal fan rotation?

Centrifugal fans operate by drawing air in through the inlet and expelling it at a 90-degree angle through the outlet. The airflow pattern is determined by the direction of impeller rotation, which can be:

• Clockwise (CW)

• Counterclockwise (CCW)
  
  

Rotation is identified when viewing the fan from the motor side. Selecting the correct direction is crucial to ensure the fan performs as intended by its design.

CBI Group’s centrifugal fans: accurate rotation for reliable performance

Based in Monza and operating since 1963, CBI Group is a leader in industrial ventilation. Our centrifugal fans are engineered with precision to deliver optimal performance, even in demanding environments.

CBI manufactures several lines of industrial fans, including:

• Industrial Centrifugal Fans → Explore the product range

CBI stands out for its reliability, custom configurations and full compliance with ISO 9001, ISO 14001, and ATEX standards.

How to determine centrifugal fan rotation direction

Determining the correct rotation direction is straightforward. It is crucial to set the direction according to the fan’s specifications to ensure proper airflow and performance. Here’s how CBI guarantees accurate rotation setup:

1. Design phase alignment - During the engineering phase, the rotation direction is determined based on system layout, airflow path, duct orientation, and required performance specifications. Whether clockwise (CW) or counterclockwise (CCW), the rotation is clearly defined and documented within the technical drawings.
   
   

2. Factory configuration - At our production facility, fans are built to match the specified rotation. The impeller and housing are assembled accordingly, and directional indicators (arrows and labels) are applied directly to the fan housing for clarity.
   
   
   

3. On-Site verification - During installation and commissioning, CBI technicians verify rotation direction by performing initial dry runs or visual checks. If powered, they temporarily activate the fan motor to observe the actual movement of the impeller and ensure it corresponds with the designed direction.
   
   
   

4. Custom configuration support - For third parts fans, CBI provides on-site technical assessments, using 3D scanning or diagnostic tools to understand system constraints and configure the fan rotation accordingly—minimising disruption and ensuring compatibility with existing ductwork.

By taking ownership of both the design intent and installation execution, CBI guarantees that every fan operates on its best—maximising airflow, performance, and system efficiency from day one.

Why choose CBI Group for your centrifugal fans?

Choosing CBI means partnering with a full-scope industrial fans expert offering:

• Complete assistance: from installation to predictive maintenance

• Revamping services for performance recovery and upgrades

• Aeraulic testing and diagnostics on-site

• Spare parts supply, including non-CBI fans

CBI ensures every fan is configured with the correct rotation, based on layout constraints, pressure requirements, and system specifications.