Static structures (e.g. – buildings) – Irreversibly reactive component
Reexamination Certificate
2003-04-16
2004-06-08
Ramirez, Ramon O. (Department: 3632)
Static structures (e.g., buildings)
Irreversibly reactive component
C052S456000, C052S656400
Reexamination Certificate
active
06745526
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a fire retardant door, and more particularly to a fire retardant wooden door having intumescent materials therein that provides additional fire resistance for preventing the spread of fire through the fire retardant wooden door and door frame.
BACKGROUND OF THE INVENTION
A fire retardant door, often referred to as a “fire door,” is installed in homes, commercial buildings, and industrial plants for preventing the passage or spread of fire from one part of the building to another. In the interest of public safety, standards have been set by governmental agencies; and by municipal, county and state building code authorities and insurance companies for the installation and performance of fire doors. The standards require that the fire retardant doors be installed in wall openings and that they pass industry-wide acceptance tests.
Standard test methods for fire door assemblies, such as ASTM E-152, UL 10(b) or NFPA 252, measure the ability of a door assembly to remain in an opening during a fire to retard the passage of the fire and evaluate the fire resistant properties of the door. In conducting such tests, doors are mounted in an opening of a fire proof wall. One side of the door is exposed to a predetermined range of temperatures over a predetermined period of time, followed by the application of a high pressure hose stream that causes the door to erode and provides a thermal shock to the assembly. Doors are given a fire rating based on the duration of the heat exposure of 20 minutes, 30 minutes, 45 minutes, one hour, 1½ hours or three hours. The door assembly receives the fire rating when it remains in the opening for the duration of the fire test and hose stream, within certain limitations of movement and without developing openings through the door either at the core or around the edge material.
Panel doors have a plurality of flat or raised panels that are connected to vertically extending stiles and horizontal rails. While panel doors are often used due to their visually attractive appearance, it is also common that they have poor resistance to fire because air is able to penetrate the door at the edges of the panels where they are connected to the stiles and rails. In turn, the oxygen present in the air seeps through the door at these joints and feeds the fire. To increase their resistance, some panel doors are made with segments of fire resistant material embedded within grooves that have been milled into the edges of the stiles, rails and panels at the seams of those elements. The implementation of the fire resistant material at these locations is usually effective to retard the rate at which the fire can burn through the joints. However, fire is still able to burn through the wooden portions of the door faster than is desired in most instances.
There remains a need for a fire retardant wooden door having intumescent materials strategically embedded within the joints for connecting the panels to the stiles and rails in order to prevent the spread of fire through the door and door frame. Further, the fire retardant wooden door should include supplemental intumescent materials on the perimeter edges of the fire resistant wooden door for preventing the spread of fire through the door and door frame. Additionally, the fire resistant wooden door should have a fire rating of at least 20 minutes.
DESCRIPTION OF THE PRIOR ART
Fire retardant wooden doors, and fire doors of various designs, configurations, structures and materials of construction have been disclosed in the prior art. For example, U.S. Pat. No. 4,441,296 to Grabendike et al. discloses a fire resistant wood door structure designed to pass the requirements of fire codes and testing laboratories. The fire resistant wood door structure includes a door assembly having a support frame assembly with a panel assembly connected to the support frame assembly. The support frame assembly includes top, bottom, side, central and transverse frame members. The panel members include a main body connected through peripheral edges by a double connector assembly. The double connector assembly functions to only remove about ⅓ of the doors' normal 1¾ inch thickness during the burn testing procedure, thus passing the fire resistant testing of 20 minutes. This prior art patent does not disclose or teach the particular door structure of the present invention, nor the use of intumescent material in the tongue and groove joints in order to provide for a fire retardant wooden door that prevents the spread of fire through the door and door frame.
U.S. Pat. No. 4,930,276 to Bawa et al. discloses a fire door window construction. The fire door includes a trim strip having inner and outer members. The inner trim member is of a high density incombustible mineral material or ceramic and is nailed in position to securely and uniformly hold the pane of glass in the door opening. The outer trim member is of a fire retardant particle board and has an exposed wood veneer facing throughout. An intumescent caulking compound is applied between an inner portion of the outer trim member and the pane of glass. This prior art patent does not disclose or teach the particular door structure of an all wooden door of the present invention, nor the use of intumescent material in the tongue and groove joints in order to provide for a fire retardant wooden door that prevents the spread of fire through the door and door frame for at least 20 minutes.
U.S. Pat. No. 5,417,024 to San Paolo discloses a fire resistant panel door. The fire resistant panel door is constructed from panels, stiles, mullion and rails having a core of fire resistant material. The door components are joined together so that the fire resistant material extends substantially continuously from side to side and from top to bottom of the finished door. The fire resistant core of each door panel is recessed within the fire resistant core of the associated rails and stiles to reduce air infiltration through the door which can compromise the door's fire resistance. This prior art patent does not disclose or teach the particular door structure of an all wooden door of the present invention, nor the use of intumescent material in the tongue and groove joints and perimeter edges in order to provide for a fire retardant wooden door that prevents the spread of fire through the door for at least 20 minutes.
U.S. Pat. No. 5,816,017 to Hunt et al. discloses a fire retardant door and exit device for the fire retardant door. The fire retardant door includes a core of fire resistant blocking material being Tectonite™ for providing the door with a fire rating of at least 90 minutes. The fire door uses intumescent material which expands when heated to fill the void in the channel between the channel walls and the vertical extending rods within the latch stile of the door. This prior art patent does not disclose or teach the particular door structure of an all wooden door of the present invention, nor the use of intumescent material in the tongue and groove joints and perimeter edges in order to provide for a fire retardant wooden door that prevents the spread of fire through the door for at least 20 minutes.
U.S. Pat. No. 6,115,976 to Gomez discloses an assembly for sealing a fire resistant door within a door frame during a fire event. The door edge assembly includes a plurality of door edges for receiving an intumescent strip within a slot on each door edge. The intumescent strip is constructed and designed to expand upon reaching a certain reaction temperature when exposed to a fire event or other extreme heat source. This prior art patent does not disclose or teach the particular door structure of an all wooden door of the present invention, nor the use of intumescent material in the tongue and groove joints in order to provide for a fire retardant wooden door that prevents the spread of fire through the door and door frame for at least 20 minutes.
U.S. Pat. Nos. 4,529,742; 6,031,040; and 6,153,674 each disclose the use of intumesc
Ramirez Ramon O.
Schulterbrandt Kofi
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