Smoke leakage (S): The duct shall not Use a leakage exceeding 5 m³/h for each one m² of inner area area. This shall be connected with the surface space on the duct through the perforated plate to the end from the duct via the inlet nozzles. Promat has formulated self-supporting https://grease-tight-extract-duct02345.izrablog.com/37341350/helping-the-others-realize-the-advantages-of-fire-resisting-ductwork-insulation