Axial fans are designed for simple installations. Generally, suitable for wall or window mounting or with short duct runs (up to 1.5 meters with 2 x 90 degree bends) axial fans are not designed for long ducts or applications at height.
To ensure that an axial fan works correctly and complies with the Building Regulations, when installing please follow the guidance below:
The inner radius of any bend should be greater or equal to the diameter of the ducting being used. If the radius is reduced, the resistance of the bend will increase and the volume of air being extracted will decrease (see “Do” diagram above).
Ensure flexible ducting is installed without peaks or troughs (see “Don’t” diagram above).