The minimum duct thickness is outlined by what ever code jurisdiction that the challenge is located in. Down below are two code references connected with the required thickness and content type for grease ducts. Overhang: The extraction Cover should overhang the cooking tools by not less than 250mm on the https://commercial-kitchen-extrac78904.iyublog.com/35984458/detailed-notes-on-grease-tight-extract-ductwork