Reinstate the fire resistance performance of wall and floor constructions Uninsulated ventilation duct assemblies are supposed for use in environments where the clearance to combustible products and combustible assemblies is no less than 18 inches. ROCKWOOL Curtainrock® is usually a stone wool insulation board created for use in ASTM E2307 https://hectormfvky.qodsblog.com/36984100/the-greatest-guide-to-fire-rated-ductworth