Grease duct joints are held together by way of formed V clamps and sealed with 3M Fire Barrier 2000+. Grease duct is possibly routed via a fire rated shaft enclosure or wrapped by having an permitted fire insulating blanket that permits for zero clearances, for example that created by 3M. https://grease-tight-extract-duct01223.blog5star.com/37330820/detailed-notes-on-grease-tight-extract-ductwork