1.5-hour A Type horizontal static curtain fire dampers are designed to protect HVAC ductwork penetrations through walls, partitions or floors rated at 2 hours or less. Fusible link releases at 165°F to drop the curtain and seal the opening, preventing the spread of fire and smoke. Designed for fan-off systems where HVAC shuts down during a fire event. Galvanized steel construction. Available in 8x8, 10x10 and 12x12 sizes.