Smoke leakage (S): The duct shall not have a leakage exceeding 5 m³/h per one m² of internal floor region. This shall be related to the surface area space from the duct from the perforated plate to the tip of your duct via the inlet nozzles. Ideal for indoor use https://fireresistingductworkinsu78900.is-blog.com/43718742/top-latest-five-fire-resisting-ductwork-insulation-urban-news