Fire resistant door, glazing, and mullion frames include intumescent
material at least partially embedded in the frame adjacent the door or
glazing. Trim materials are positioned over the intumescent material to
prevent tampering with and damage to the intumescent material while
improving the aesthetic appearance of the frame. The jamb trim has a
thickness that allows heat to be transmitted to the intumescent material
in the event of a fire so that the intumescent material will expand and
fill a clearance space between the frame and the door or glazing. The
expanded intumescent material retards the passage of heat and, by sealing
the clearance space, inhibits the transmission of smoke, flames and gases
from one side of the door or glazing to the other. After expanding, the
intumescent material will char and solidify, which may provide an added
benefit of structural support for the door or glazing.