BAS-CVS Dynamic Fire Dampers are intended for use in dynamic HVAC systems that remain operational during an event of a fire, and may also be employed in static systems. BAS-CVS dynamic fire dampers are available in a wide range with 1-1/2-hour & 3-hour fire endurance ratings; tested at minimum 2000 feet per minute at 4 in. w.g. of static pressure. As required by the NFPA-90A Chapter 5 & IBC Chapter 7, 1-1/2-hour fire dampers are required in walls, floors, and partitions with a fire-resistance rating of less than 3 hours; whereas, 3-hour dampers are applied when there are fire ratings of 3-hours or more.