Smoke leakage (S): The duct shall not Use a leakage exceeding 5 m³/h for each one m² of inner area location. This shall be related to the surface area place from the duct through the perforated plate to the top from the duct because of the inlet nozzles. Pressurisation ducts https://riverxmaas.laowaiblog.com/35899147/5-essential-elements-for-fire-resisting-ductwork-insulation