UL certifies fire doors under a variety of different product categories that reflect the type or use of the door and the criteria used to evaluate them.
Some fire doors are supplied as complete assemblies, including the frame, hardware and other accessories. In other cases, fire doors are supplied independently from the other components, and are assembled at the job site with the fire door frame, glazing, hardware, and/or other accessories to form a fire door assembly, which provides the degree of fire protection required for the opening.
Fire-protection ratings – Fire doors include a rating of 4, 3, 1-1/2, 1, and ¾ hours, or 30 or 20 minutes, which indicates the duration of exposure to fire. For products intended for use in regions outside of North America, fire doors may be rated with a 3-hour rating in accordance with local building practices.
Temperature rise ratings – Some fire doors contain a temperature-rise rating on the Certification Mark. This rating is intended for use in determining compliance with the temperature-rise requirements contained in the International Building Code, NFPA 101, and NFPA 5000. A temperature-rise rating of 250°F, 450°F or 650°F reflects the limiting potential temperature rise on the unexposed surface of the door during the first 30 minutes of fire exposure. Certification Marks that do not indicate a temperature rise are for doors which either develop a temperature rise in excess of 650°F on the unexposed surface of the door or have not been evaluated for a temperature rise rating.
Glass lights in fire doors in excess of 100 sq. in. shall be fire-resistance rated and shall also be evaluated as a component of the door assembly in accordance with UL 10B or UL 10C where the door is rated for a duration greater than 45 minutes. Doors with glass light panels meeting the size limitations and the rating requirements of the installation code carry the same rating as similar doors without glass light panels.
