ATAI AFSD & WGBD series are ideal fire and smoke dampers for applications where building codes require both a fire damper for the fire protection in ductwork penetration and a leakage rated damper for operational smoke control. The AFSD series are UL listed according to UL 555 and 555S with 1-1/2 hours and 3 hours fire rating. Whereas the WGBD series is Warrington certified up to 4-hour fire rating according to BS 476 part 20 standard.