Replacement Blowers for Air Handling Units Energy efficient half scroll, H-frame and X-frame flange / baseplate mounted fan assemblies. Half scroll assemblies can be mounted from either flange or base plate and are ideal for any application where the airflow needs to be turned through 90 degrees. The scroll design is optimised around the fan design for maximum performance.,The H and X-frame assemblies are well suited for AHU's (air handling units), box fans or roof extract units as the air can be exhausted in any direction, horizontally or vertically. Industrial Plate Fans