Smoke leakage (S): The duct shall not Have a very leakage exceeding five m³/h per 1 m² of interior surface spot. This shall be associated with the floor location of your duct from your perforated plate to the tip of your duct through the inlet nozzles. CE & UKCA marked https://fireresistingductworkinsu57789.dreamyblogs.com/37281206/grease-tight-extract-ductwork-no-further-a-mystery