Ducts with cross-sectional length greater than 1,200mm are recommended to be split into two or more ducts, whereever possible.
The proposed duct sizes are for the cross-sectional dimensions of the ducts as the linear length is determined by location of the room(s).

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The calculator on this page is offered to assist in generating general estimations only, for basic applications. If you are unsure or would like assistance analysing your current situation, feel free to contact us with your questions. Please contact us for professional advice from one of our engineers.