Smoke leakage (S): The duct shall not Use a leakage exceeding 5 m³/h for each 1 m² of interior floor location. This shall be related to the area spot from the duct within the perforated plate to the tip of the duct via the inlet nozzles. Fire resistant board for https://fire-resisting-ductwork-i80122.blogsmine.com/37413329/a-review-of-grease-tight-extract-ductwork