There are plenty of accepted methods of producing a welded joint for grease exhaust ductwork. The alternatives will rely upon the code in your jurisdiction but must include flanged, telescoping, Bell sort or overlapping joints. CE & UKCA marked Ducts that cross from the escape corridor (demonstrated in blue) have https://brooksaqesf.thekatyblog.com/35386156/indicators-on-fire-resisting-ductwork-insulation-you-should-know