Combination Fire Smoke dampers are available in 3V blades for use in systems up to 2000 fpm and 6 in. wg or airfoil blades for use in systems up to 4000 fpm and 4 in. wg. All models have been tested and are labeled in accordance with UL 555 and UL 555S. Fire resistance ratings of either 1 1/2 or 3 hours and leakage class ratings of I, II, or III
