There are many authorised methods of making a welded joint for grease exhaust ductwork. The possibilities will depend on the code for the jurisdiction but should really involve flanged, telescoping, Bell type or overlapping joints. CE & UKCA marked Ducts needs to be manufactured from non-combustible products like metal, meant https://finnrhvkx.mybuzzblog.com/16891641/5-essential-elements-for-grease-tight-extract-ductwork