The 634 Series rolling steel, fire-rated service door offers superior protection wherever a listed fire door is required. Common applications include factories, warehouses, mills, distribution centers and parking garages. Customized fire doors are available for conveyor openings. These doors feature fusible links mounted on both sides of the wall that separate to automatically close the door. UL recommends a 165°F (74°C) fuse link for ambient conditions for 100°F (38o°C) or less, or a 212°F (100°C) fuse link for ambient conditions over 100°F (38°C). Added protection features, such as Fire Sentinel™ and FireLite® vision lites are optional.