Door and glazing frames include intumescent material positioned in a dado
that is formed in a jamb side surface. Trim materials are positioned over
the intumescent material to improve the appearance of the frame and to
prevent tampering with and damage to the intumescent material. The jamb
trim is preferably made of a cut hardwood panel having 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 inhibits the transmission of smoke and heat between the door and
door frame. After expanding, the intumescent material will char and
solidify, which may provide an added benefit of structural support for
the door and or glazing.