Grease duct joints are held with each other by the use of formed V clamps and sealed with 3M Fire Barrier 2000+. Reduction in cross-area: The interior dimensions (width and peak for rectangular ducts, diameter for round ducts) with the smoke extracting ductwork shall not minimize by greater than 10% https://fireresistingductworkinsu68912.blog-eye.com/37248214/not-known-factual-statements-about-grease-tight-extract-ductwork