Grease duct joints are held with each other through fashioned V clamps and sealed with 3M Fire Barrier 2000+. The bare minimum duct thickness is outlined by what ever code jurisdiction which the undertaking is situated in. Beneath are two code references relevant to the needed thickness and product sort https://grease-tight-extract-duct13344.csublogs.com/44174487/5-tips-about-fire-resisting-ductwork-insulation-you-can-use-today