A centrifugal or ‘radial’ fan is a mechanical device designed to move air or gas. It operates by utilising centrifugal force to blow air at right angles to the intake of the fan, spinning the air outwards towards the outlet. The fan comprises an impeller that rotates within a scroll-shaped casing. Air enters near the shaft of the impeller and is propelled perpendicularly outward through the fan’s outlet as the impeller spins.
Centrifugal fans are capable of producing higher pressure compared to axial fans, making them particularly suitable for applications requiring longer duct runs or higher resistance to airflow. These fans are commonly used in ventilation systems, heating, and cooling applications, as well as in industrial and residential settings.
Key Features
- Airflow Direction: Perpendicular to the intake.
- Pressure Output: High-pressure airflow, ideal for overcoming resistance in ducting systems.
- Design: Scroll-shaped casing to efficiently direct airflow.
- Types: Can be inline duct fans or wall-mounted fans.
Applications in the UK House Building and Retrofit Sectors
- Ventilation Systems:
- Centrifugal fans are used in mechanical ventilation systems, such as Centralised Mechanical Ventilation with Heat Recovery (MVHR) units, to ensure consistent airflow throughout a property.
- In retrofitting projects, they are often installed to improve air quality in homes with reduced natural ventilation due to airtightness measures like double glazing or external wall insulation.
- Wet Rooms:
- Wall-mounted centrifugal fans are commonly used in bathrooms, kitchens, and utility rooms to extract humid air and prevent dampness or mould growth. For example, the ARIA unit from VENTI is a decentralised mechanical extract ventilator (DMEV) that continuously removes moisture and airborne pollutants in wet rooms.
- Long Duct Runs:
- In larger homes or multi-storey buildings, centrifugal fans are preferred due to their capability to maintain airflow over long duct distances, ensuring compliance with Approved Document Part F of the UK Building Regulations.