This invention relates in general to fire resistant structures and, more particularly, to a fire resistant door.
Fire barriers are included within the design of many types of buildings in order to block the spread of a fire once it has been ignited within the building. Because the placement of door openings in the walls of the building provides an avenue for the fire to spread from room to room, much attention has been focused on the designing of doors which are fire resistant and can impede the spread of the fire.
Panel doors have a plurality of flat or raised panels interconnected with vertically extending stiles and horizontal rails. Although panel doors are widely utilized because of their visually pleasing appearance, they generally have poor resistance to fire because air is able to infiltrate the door at the juncture of the panels with the stiles and rails. The fire is fed by the oxygen present in the air which seeps through the panel joints and can quickly burn through the door at those joints. In an effort to increase their fire resistance, some panel doors are available which have segments of fire resistant material inserted within grooves milled into the edges of the stiles, rails and panels at the junctures of those components. The placement of the fire resistant material at those locations is generally effective to slow the rate at which the fire can burn through the panel joints, but the fire is still able to burn through the wooden portions of the door at a faster rate than is desired in many instances.
Another type of conventional fire resistant door mimics the appearance of a panel door by applying half panels to a core of fire resistant material. The core comprises a solid sheet of material which is milled on both faces to form recesses at the intended location of the panels. Half panels are then positioned within the recesses and veneer and trim are applied to the exposed surfaces of the core. The resulting door can be very resistant to fire because the solid core blocks any air infiltration through the door. The milling operation, however, may reduce the structural integrity of the door and result in warping, sagging or other deformation of the door.
A need thus exists for a panel door which has an enhanced fire resistance but maintains the desired structural and visual appearance.