Smoke leakage (S): The duct shall not have a leakage exceeding 5 m³/h for every 1 m² of inside area location. This shall be connected to the surface area place from the duct with the perforated plate to the top in the duct via the inlet nozzles. Large access panels https://greasetightextractductwor24566.newsbloger.com/37587059/grease-tight-extract-ductwork-secrets