Code Applications and Interpretations

Section 4306 (g)

Q: In a one-hour-rated door assembly with side lights placed in a one-hour occupancy separation wall, what is the maximum allowable size of glazing?

A: Glazed sidelights are not permitted in a one-hour-rated door assembly. Section 4306 (d) states in part that "Fire door frames...shall be installed in accordance with their listing." The listing requirements of approved testing agencies, such as Underwriters Laboratories Inc., refer to National Fire Protection Association (NFPA) Standard 80, Standard for Fire Doors and Windows. Section 2.6 of that standard requires side panels andtransoms to be solid in frames where a rating greater than three-fourths hour is required. Therefore, glazing in the side lights and transom would not be permitted in a one-hour assembly. Glazing is permitted in the door itself (up to one-and-one-half-hour rating), and the glazing is limited to 100 square inches as stated in Section 4306 (g).

Section 43.301 of Uniform Building Code Standard No. 43-4, which is referenced by U.B.C. Section 4306 (i), limits the rating of light-transmitting (or window) assemblies to 45 minutes. Section 13-2 of NFPA 80 limits the size of an individual pane in a three-fourths-hour-rated window assembly. If tested as such, a three-fourths-hour fire-resistive-rated door assembly. If tested as such, a three-fourths-hour-rated door assembly could include more than one pane of glass, as long as each pane is less than the 1,296 square inches.

For a window to be rated as a separated one-hour fire-resistive assembly, it would have to be tested as a wall assembly (or a portion of a wall assembly) in accordance with U.B.C. Standard No. 43-1, which would include the requirements for heat transmission, It would be extremely difficult for transparent glazing to comply with these heat transmission requirements, although some systems have been tested to this standard.