Fire retardant panel door and door frame having intumescent materials therein

Abstract

A fire retardant panel door and door frame that prevents the spread of fire through the door during a fire. The fire retardant panel door has at least one door panel and stiles and rails. The door panel includes an interior center composite section formed by a first plurality of layers of intumescent materials and a first plurality of layers of fire resistant materials disposed between and laminated to a pair of outer sections formed of wood for enclosing the interior center composite section to form a composite laminated door panel. Each of the stiles includes a first center core formed of wood enclosed by a second plurality of layers of intumescent materials and a second plurality of layers of fire resistant materials; and the second layers of intumescent and fire resistant materials are enclosed by a first applique layer formed of wood to form a composite laminated stile. Each of the rails includes a second center core formed of wood enclosed by a third plurality of layers of intumescent materials and a third plurality of layers of fire resistant materials; and the third layers of intumescent and fire resistant materials are enclosed by a second applique layer formed of wood to form a composite laminated rail. The first, second, and third plurality of layers of intumescent materials are activated to expand upon exposure to heat and/or fire to prevent the heat and/or fire from passing through at least one door panel, the stiles and the rails of the panel door during a fire for at least 90 minutes. At least one door panel is connected to the panel door by tongue and groove joints; and the tongue and groove joints have a fourth plurality of layers of intumescent materials and a fourth plurality of layers of fire resistant materials in the tongue and groove joints; and wherein the fourth plurality of layers of fire resistant materials in the tongue and groove joints are activated to expand upon exposure to heat and/or fire to seal the joints in order to prevent the heat and/or fire from passing through the panel door during a fire for at least 90 minutes.

Description

FIELD OF INVENTION

The present invention relates to a fire retardant panel door and door frame, and more particularly to a fire retardant panel door and door frame that provides fire resistance using a plurality of intumescent and fire resistant barrier layers therein for preventing the spread of fire through the fire retardant panel door and door frame.

BACKGROUND OF THE INVENTION

A fire retardant panel 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.

A fire door must be made almost entirely of incombustible material. However, since a fire door is part of the interior or exterior of a personal living space or workspace, it must also be aesthetically pleasing. Usually, therefore, a core of incombustible material comprising the main structure of the fire door is overlaid with a thin wood veneer facing that provides the door with an attractive appearance. Fire door assemblies often fail, not because of the fire resistant properties of the fire door, but they fail because of inadequate placement of the fire resistance materials within the door, such that the fire door buckles. Additionally, the fire resistant blocking material of a core section of the fire door may need supplemental fire resistant materials strategically placed within the fire door to add to its fire door rating.

There remains a need for a reinforced fire retardant panel door and door frame which provides additional fire resistance using layers of intumescent and fire resistant materials in the fire retardant panel door and door frame in order to prevent buckling of the fire retardant panel door and door frame during a fire. Further, the reinforced fire retardant panel door would include supplemental layers of fire resistant materials strategically embedded within the structural components of the fire retardant panel door.

DESCRIPTION OF THE PRIOR ART

Fire retardant 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. 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 having the use of intumescent and fire resistant materials in the door panel, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire, as well as prevent the spread of fire through the door and door frame for at least 90 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 having the use of intumescent and fire resistant materials in the door panels, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire, as well as prevents the spread of fire through the door and door frame for at least 90 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 having the use of intumescent and fire resistant materials in the door panels, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire for at least 90 minutes.

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 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 having the use of intumescent and fire resistant materials in the door panels, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire, as well as prevents the spread of fire through the door and door frame for at least 90 minutes.

U.S. Pat. No. 4,441,296 to Grabendike et al. discloses a fire resistant wood door structure designed to pass code and testing laboratories' requirements. 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 a peripheral edge by a double connector assembly. The double connector assembly functions to only remove about ⅓ of the door's 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 having the use of intumescent and fire resistant materials in the door panels, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire, as well as prevents the spread of fire through the door and door frame for at least 90 minutes.

U.S. Pat. Nos. 4,529,742; 6,031,040; and 6,153,674 all disclose the use of intumescent compounds/fire barrier materials within door construction to reduce or eliminate the passage of smoke and fire through the door and door frame. These prior art patents do not disclose or teach the particular door structure having the use of intumescent and fire resistant materials in the door panels, stiles, rails, door frame and door joints in order to provide for a fire retardant panel door that prevents buckling of the door during a fire, as well as prevents the spread of fire through the door and door frame for at least 90 minutes.

In addition, the aforementioned prior art patents do not disclose or teach the particular structure and configuration of the reinforced fire retardant panel door and door frame of the present invention that provides additional fire resistance to the door in order to prevent the buckling of the door during a fire.

Accordingly, it is an object of the present invention to provide a reinforced fire retardant panel door and door frame that prevents buckling of the door during a fire.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that has supplemental fire resistant materials strategically embedded and placed within the tongue and groove joints of the fire resistant panel door, as well as supplemental fire resistant materials placed on the perimeter edges of the fire resistant panel door for preventing the spread of fire through the door and door frame.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that has intumescent and fire resistant material layers within the panel door and door frame for preventing the spread of fire through the door and door frame.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that has fire resistant materials being multiple layers of intumescent material that expands in the presence of fire such that the intumescent material closes and seals the component tongue and groove joints, as well as the perimeter edges of the fire retardant panel door for preventing the spread of fire through the door and door frame.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that is used as part of an interior or exterior personal living space, or workspace being installed within home dwellings, commercial buildings or industrial plants.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that has stiles and rails having metal L-shaped beads therein in order to form an exoskeleton for further strengthening and tying together the stiles and rails within the panel door in order to keep the panel door from buckling during a fire.

Another object of the present invention is to provide a reinforced panel door and door frame that has improved aesthetic qualities by having a maximum panel core thickness of ⅜ of an inch allowing for a minimum thickness of 1¾ inches of the fire resistant and reinforced panel door which allows for greater profiling (depth) of the exterior wood molding between the center panel and the stiles and rails.

Another object of the present invention is to provide a reinforced panel door and door frame that includes a heat activated door pin or door hook assembly for preventing the active (free) panel door from buckling during a fire.

Another object of the present invention is to provide a reinforced fire retardant panel door and door frame that is aesthetically pleasing having the appearance of natural wood, and has achieved a successful fire rating of at least 90 minutes and passes a positive pressure test, and is easily installed in a building.

A further object of the present invention is to provide a reinforced fire retardant panel door and door frame that can be mass produced in an automated and economical matter and is readily affordable to the builder or consumer.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a fire retardant panel door and door frame that prevents the spread of fire through the door during a fire. The fire retardant panel door has at least one door panel and stiles and rails. The door panel includes an interior center composite section formed of a first plurality of layers of intumescent materials and a first plurality of layers of fire resistant materials disposed between and connected to a pair of outer sections formed of wood for enclosing the interior center composite section to form a composite laminate door panel. Each of the stiles includes a first center core formed of wood enclosed by a second plurality of layers of intumescent materials and a second plurality of layers of fire resistant materials; and the second layers of intumescent and fire resistant materials materials are enclosed by a first applique layer formed of wood to form a composite laminate stile. Each of the rails includes a second center core formed of wood enclosed by a third plurality of layers of intumescent materials and a third plurality of layers of fire resistant materials; and the third layers of intumescent and fire resistant materials are enclosed by a second applique layer formed of wood to form a composite laminate rail. The first, second, and third plurality of layers of intumescent materials are activated to expand upon exposure to heat and/or fire to prevent the heat and/or fire from passing through the at least one door panel, the stiles and the rails of the panel door during a fire for at least 90 minutes. The at least one door panel is connected to the panel door by tongue and groove joints; and the tongue and groove joints have a fourth plurality of layers of intumescent materials and a fourth plurality of layers of fire resistant materials in the tongue and groove joints; and wherein the fourth plurality of layers of intumescent materials in the tongue and grove joints are activated to expand upon exposure to heat and/or fire to seal said joints in order to prevent the heat and/or fire from passing through the panel door during a fire for at least 90 minutes.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the present invention will become apparent upon the consideration of the following detailed description of the presently-preferred embodiment when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front perspective view of the fire retardant panel door and door frame of the first embodiment of the present invention showing a single door and a door frame and its major component parts thereof;

FIG. 2 is a cross-sectional view of the fire retardant panel door and door frame of the first embodiment of the present invention taken along lines 2-2 of FIG. 1 in the direction of the arrows showing intumescent materials within tongue and groove joints of a center panel, stiles and rails, and intumescent materials within a door frame;

FIG. 2A is a sectional view of the fire retardant panel door and door frame of the present invention showing an upper corner of a stile and upper header having a heat activated door pin assembly therein in an unexpanded configuration;

FIG. 2B is a sectional view of the fire retardant panel door and door frame of the present invention showing the upper corner of the stile and upper header having the heat activated door pin assembly therein in an expanded configuration;

FIG. 3 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along lines 3-3 of FIG. 1 in the direction of the arrows showing the panel connected to opposing stiles within the door frame;

FIG. 4 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along line 4-4 of FIG. 1 in the direction of the arrows showing the lower rail connected to opposing stiles within the door frame;

FIG. 4A is an enlarged sectional detailed view of the fire retardant panel door and door frame of the present invention showing the tongue and groove joint and a pair of dowel pins for joining the lower rail to the opposing stile;

FIG. 5 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along lines 5-5 of FIG. 1 in the direction of the arrows showing the center panel connecting the upper rail and the lower rail within the door frame;

FIG. 6 is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the stile having a plurality of intumescent layers surrounding a wood core, and the center panel having an interior center composite section of intumescent layers;

FIG. 7 is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the rail having a plurality of intumescent layers surrounding a wood core, and the center panel having an interior center composite section of intumescent layers;

FIG. 8 is an enlarged exploded sectional detailed view of the fire retardant panel door of the present invention showing the tongue and groove joint for joining the center panel to the rail;

FIG. 9 is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing a tongue section of the center panel having the interior center composite section with a plurality of intumescent layers therein;

FIG. 10 is an enlarged sectional detailed view of the fire retardant door frame of the present invention showing a doorjamb or an upper header having a plurality of intumescent layers surrounding a wood core;

FIG. 11 is a front perspective view of the fire retardant panel doors and door frame of the second embodiment of the present invention showing a double door assembly within a double door frame and their major component parts thereof;

FIG. 12 is a cross-sectional view of the fire retardant panel doors and door frame of the second embodiment of the present invention taken along lines 12-12 of FIG. 11 in the direction of the arrows showing intumescent materials within tongue and groove joints of a plurality of panels, stiles, rails, and mullions within each of the doors of the double door assembly and intumescent materials within a double door frame;

FIG. 12A is a sectional view of the fire retardant panel door and door frame of the present invention showing a dead bolt assembly within one of the upper corners of a stile and upper jamb header of a first panel door;

FIG. 12B is a sectional view of the fire retardant panel door and door frame of the present invention showing one of the upper corners of a stile and upper header having a heat activated door pin assembly therein of a second panel door in an unexpanded configuration;

FIG. 12C is a sectional view of the fire retardant panel door and door frame of the present invention showing one of the upper corners of the stile and upper header having the heat activated door pin assembly therein of the second panel door in an expanded configuration;

FIG. 12D is a perspective view of the fire retardant panel door and door frame of the present invention showing the heat activated door pin assembly in an unexpended configuration and tensioned state;

FIG. 12E is a sectional view of the fire retardant panel door and door frame of the present invention showing one of the upper corners of the stile and upper header having a heat activated door hook assembly therein of the second panel door in an unexpanded configuration and tensioned state;

FIG. 12F is a sectional view of the fire retardant panel door and door frame of the present invention showing one of the upper corners of the stile and upper header having the heat activated door hook assembly therein of the second panel door in an expanded configuration and untensional state;

FIG. 12G is a perspective view of the heat activated door hook assembly of the present invention showing the door hook assembly in its untensioned state;

FIG. 12H is a top plan view of the heat activated door hook assembly of the present invention showing a strike plate, a movable door hook member, and a fusible solder link;

FIG. 12I is a bottom plan view of the heat activated door hook assembly of the present invention showing a door hook housing member having an opening for accessing the door hook member and the strike plate;

FIG. 12J is a side elevational view of the heat activated door hook assembly of the present invention showing the strike plate, the movable door hook member and the door hook housing member and the door hook housing member in an expanded configuration and untensioned state;

FIG. 13 is a cross-sectional view of the fire retardant panel doors and door frame of the present invention taken along lines 13-13 of FIG. 11 in the direction of the arrows showing each of the panels connected to opposing stiles for each door within the double door frame;

FIG. 14 is a cross-sectional view of the fire retardant panel doors and door frame of the present invention taken along lines 14-14 of FIG. 11 in the direction of the arrows showing each of the lower rails connected to opposing stiles for each door within the double door frame;

FIG. 15 is a cross-sectional view of the fire retardant panel doors and door frame of the present invention taken along lines 15-15 of FIG. 11 in the direction of the arrows showing a first mullion connected to opposing stiles for the second door within the double door frame;

FIG. 16 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along lines 16-16 of FIG. 11 in the direction of the arrows showing the panel, an interior raised panel, an interior stile, and the opposing stiles of one of the doors being set within the door frame;

FIG. 17 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along lines 17-17 of FIG. 11 in the direction of the arrows showing the panel connected to opposing rails of the first door within the double door frame;

FIG. 18 is a cross-sectional view of the fire retardant panel door and door frame of the present invention taken along lines 18-18 of FIG. 11 in the direction of the arrows showing the panels connecting the opposite rail and the mullions within the double door frame;

FIG. 18A is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing a stile within the second panel door;

FIG. 19A is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the stile having a plurality of intumescent layers surrounding a wood core, and the panel having an interior center composite section of intumescent layers for the first door panel;

FIG. 19B is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the stile having a plurality of intumescent layers surrounding a wood core, and the panel having an interior center composite section of intumescent layers for the second panel door;

FIG. 20A is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the rail having a plurality of intumescent layers surrounding a wood core, and the panel having an interior center composite section of intumescent layers for the first door panel;

FIG. 20B is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing the rail having a plurality of intumescent layers surrounding a wood core, and the panel having an interior center composite section of intumescent layers for the second panel door;

FIG. 21 is an enlarged exploded sectional detailed view of the fire retardant panel door of the present invention showing the tongue and groove joint for joining the upper panel to the upper rail for the second panel door;

FIG. 22 is an enlarged sectional detailed view of the fire retardant panel door of the present invention showing a tongue section of the panel having the interior center composite section with a plurality of intumescent layers therein; and

FIG. 23 is an enlarged sectional detailed view of the fire retardant door frame of the present invention showing a door jamb or an upper header having a plurality of intumescent layers surrounding a wood core.

DETAILED DESCRIPTION OF THE EMBODIMENTS

First Embodiment 10

The fire retardant panel door 10 and door frame 30 of the first embodiment of the present invention is represented in detail by FIGS. 1 through 10 of the patent drawings. The fire retardant panel door 10 and door frame 30 is used to fireproof an area and to prevent fire from spreading to other areas within a home dwelling, a commercial building, or an industrial plant.

Fire retardant panel door 10 includes stiles 12 and 14, rails 16 and 18, and a center panel 20, as shown in FIGS. 1 and 3 to 5. The fire retardant panel door 10 is hingedly connected to the door frame 30, as depicted in FIG. 1, such that the panel door 10 is hingedly connected between a left or right door jamb 32 or 34 and positioned below an upper header 36, as depicted in FIGS. 3 and 4 of the drawings. Jambs 32 and 34 include an interior wall surface 33 and 35, respectfully, and upper header 36 includes an interior wall surface 37.

As shown in FIGS. 3, 4, and 5, the stiles 12 and 14 and rails 16 and 18 have a solid core section 40 formed of a yellow poplar microllam wood material. A composite intumescent and fire resistant layer section 50 partially surrounds and encloses the solid wood core section 40 on sides 51 and 53, respectively. A wood applique 42 (i.e., oak, maple, walnut, etc.) encloses the composite intumescent and fire resistant layer sections 50 of sides 51 and 53, respectively. The composite intumescent and fire resistant layer section 50 includes a first inner intumescent layer 52 being adjacent to and in contact with the solid wood core section 40, a second middle fire resistant barrier layer 54 being adjacent to and in contact with the first inner intumescent layer 52, and a third outer intumescent layer 56 being adjacent to and in contact with the second middle fire resistant barrier layer 54, as shown in FIGS. 6 and 7.

The inner and outer intumescent layers 52 and 56 of sides 51 and 53 are made of PALUSOL P-210™ product being manufactured by the BASF Corporation of the USA. PALUSOL P-210™ is an intumescent panel consisting essentially of a core having sodium silicate, and a small portion of organic binder reinforced by glass fibers and having the addition of wire mesh therein. A coating of epoxy resin is applied to each side of the core which protects the intumescent panel from atmospheric influences of carbon dioxide, water, and/or steam. The mass per unit area of the intumescent laminate (panel) layer 52 or 56 is in the range of 0.46 to 0.77 pounds per foot². The thickness of the intumescent laminate layer 52 or 56 is in the range 0.0590 inches to 0.0906 inches.

The second middle layer 54 of sides 51 and 53 is made of a FYRE ROC™ (FR-1001) product being manufactured by the Goodrich Corporation, Engineered Polymer Products Division, of Jacksonville, Fla., U.S.A. The FYRE ROC™ panel is a laminate sheet consisting of a fire resistant metallo alumino silicate and stainless steel screen layers for forming a reinforced composite laminate sheet that has the ability to maintain excellent mechanical and physical properties at elevated temperatures up to 2000 degrees Fahrenheit, without significant smoke or toxicity emissions. The density of the laminate fire resistant barrier (sheet) layer 54 is 2.5±0.5 grams per cubic centimeter. The thickness of the laminate fire resistant barrier layer 54 is in the range of 0.020 to 0.050 inches (due to reinforcement thickness variability).

The wood applique 42 is adjacent to and in contact with the third outer intumescent layer 56. Wood molding 44 is applied to the exterior surface of stiles 12 and 14, rails 16 and 18, and center panel 20, as shown in FIG. 1 of the drawings. The aforementioned wood applique 42, intumescent layers 52, 54, and 56, and the solid wood core section 40 are laminated together under pressure P using an adhesive system consisting of a Simpson ISR 70-07 isocyanate adhesive A or an equivalent adhesive in order to form the laminated stiles 12 and 14 and rails 16 and 18, respectively, as depicted in FIGS. 6 and 7 of the drawings.

As shown in FIGS. 3, 4 and 5, the stiles 12 and 14 and rails 16 and 18 also include inner and outer ends 55 and 57, respectively. The inner end 55 includes a first inner intumescent end layer 58 being adjacent to and in contact with the solid wood core section 40, and a second middle intumescent end layer 64 being adjacent to and in contact with the first inner intumescent layer 58. The first and second intumescent end layers 58 and 64 of inner end 55 are made of the PALUSOL™ P-210 product as previously described. The outer end 57 includes a first inner intumescent end layer 62 being adjacent to and in contact with the solid wood core section 40, a second middle intumescent end layer 64 being adjacent to and in contact with the first inner intumescent end layer 62, a third outer intumescent end layer 66 being adjacent to and in contact with the second middle intumescent end layer 64 and the wood applique (veneer) 42 being adjacent to and in contact with the third outer intumescent end layer 66. The first inner intumescent end layer 62 is made of the PALUSOL™ P-210 product as previously described. The second and third intumescent end layers 64 and 66 are made of a TECHNOFIRE 2000™ product manufactured by the TECHNICAL FIBRE PRODUCTS SUBSIDIARY in Newburgh, N.Y., U.S.A. The TECHNOFIRE 2000™ rigid sheet panel is a composite laminate sheet consisting of a core having rockwool fibers with chopped strand glass fibre reinforcement and a small portion of organic binder. A coating of epoxy resin is applied to each side of the core which protect the composite intumescent panel from atmospheric influences of carbon dioxide, water and/or steam. The density of the composite intumescent laminate sheet end layers 64 or 66 is in the range of 78.0 to 90.5 5 lbs/ft³ (1250 to 1450 kg/m³). The intumescent laminate end layers 64 or 66 has a maximum thickness of 1.3 mm (0.0512 inches). The mass per unit area of the intumescent laminate end layers 64 or 66 is in the range of 0.333 to 0.386 pounds per foot². The intumescent laminate end layers 64 or 66 upon exposure to heat and/or fire has expansion ratio of 22:1 for imparting linear gap seals between the fire retardant panel door 10 and door frame 30 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 10 and door frame 30.

Additionally, as shown in FIGS. 3, 4 and 5, the stiles 12 and 14 and rails 16 and 18 further include a plurability of metal L-shaped beads 68 made from 16 gauge galvanized steel being positioned at the corners 69a, 69b, 69c and 69d of the stiles 12 and 14, and rails 16 and 18. The metal L-shaped beads 68 each include a first end section 68f and a second end section 68s. Each of the second end sections 68s of metal L-shaped beads 68 are further positioned and placed between the second middle fire resistant barrier layer 54 and the third outer intumescent layer 56, as shown in FIGS. 3, 4 and 5 of the drawings. One pair of the first end sections 68f at the inner end 55 are further positioned and placed in contact with and adjacent to the second middle end layer 60. The other pair of the first end sections 68f at the outer end 57 are further positioned and placed between the first inner intumescent end layer 62 and the second middle intumescent end layer 64. The aforementioned metal L-shaped beads 68 are used for rigidity and retention of the second middle fire resistant barrier layers 54 and the third outer intumescent layers 56 together and in conjunction with each other to form an exoskeleton layer E_x, as shown in FIGS. 3, 4 and 5 of the drawings, in order to further strengthen and tie together stiles 12 and 14 and rails 16 and 18, respectively. Each of the metal L-shaped beads 68 are fastened at the inner and outer ends 55 and 57 of the stiles 12, 14 and rails 16, 18 by brads 120n and staples 120s, respectively, as shown in FIGS. 7 and 8.

Center panel 20 has edges 61, 63, 65 and 67. The center panel 20 is formed from a composite laminate structure 70, as shown in FIG. 9. The composite laminate structure 70 includes outer wood sections 72 and 76 and an interior center intumescent and fire resistant barrier section 74 sandwiched between outer wood sections 72 and 76. The interior center intumescent and fire resistant barrier composite section 74 includes a first outer intumescent layer 78, a second inner fire resistant barrier layer 80, a third middle intumescent layer 82, a fourth middle intumescent layer 84, a fifth inner fire resistant barrier layer 86, and a sixth outer intumescent layer 88. The first outer, third middle fourth middle, and sixth outer intumescent layers 78, 82, 84, and 88 are made of the PALUSOL™ P-210 product. The second inner and fifth inner fire resistant barrier layers 80 and 86 are made of the FYRE ROC™ fire resistant laminate sheet, as previously described. The aforementioned outer wood sections 72, 76 and the intumescent layers 78 to 88 are laminated together under pressure P using an adhesive system consisting of a Simpson ISR 70-07 isocyante adhesive A or an equivalent adhesive in order to form the laminated center panel 20.

Tongue and groove joints 90 and 92 are used to connect center panel 20 to stiles 12 or 14, respectively, and tongue and groove joints 94 and 96 are used to connect center panel 20 to rails 16 or 18, respectively, as depicted in FIGS. 3, 4, and 5 of the drawings. Tongue and groove joints 98 and 100 are used to connect rails 16 or 18 to stiles 12 or 14, respectively, as shown in FIGS. 6 and 7 of the drawings. As shown in FIG. 6, the tongue and groove joints 90 and 92 include air gaps 104 for expansion of the intumescent material layers 78, 82, 84 and 88 in the presence of excessive heat and/or fire, such that the intumescent material layers 78, 82, 84 and 88 close and seal the air gaps 104 within the fire retardant panel door 10 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 10 and door frame 30. Further, the tongue and groove joints 94 and 96 also include air gaps 108, as shown in FIG. 8, for expansion of the intumescent material layers 78, 82, 84 and 88 in the presence of excessive heat and/or fire, such that the intumescent material layers 78, 82, 84 and 88 close and seal the air gaps 108 within the fire retardant panel door 10 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 10 and door frame 30. Additionally, the tongue and groove joints 98 and 100, as shown in FIGS. 4 and 4A, include air gaps 112 for expansion of the intumescent end layers 58 and 60 in the presence of excessive heat and/or fire, such that the intumescent end layers 58 and 60 close and seal the air gaps 112 within the fire retardant panel door 10 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel 10 and door frame 30. Also, the tongue and groove joints 90 and 92, and 94 and 96 are attached to each other using a staple 120s or nail 120n, respectively, as shown in FIGS. 6 and 7 of the drawings. Further, each of the rails 16, 18, and stiles 12, 14 include a dowel groove 122, 123, 124 and 125, respectively, for receiving a wooden dowel 126 therein, for additionally joining together the rails 16 and 18 to the stiles 12 and 14, respectively, as shown in FIGS. 4 and 4A. The dowels 126 are held in place within dowel grooves 122, 123, 124 and 125 with appropriate wood glue G, as depicted in FIG. 4.

As shown in FIGS. 3, 4, and 10, the jambs 32 and 34, and upper head 36 of door frame 30 include a core section 140 formed of wood materials, such as oak, maple, walnut, pine, poplar and the like. Wood applique 142 (i.e., oak, maple, walnut, etc.) is applied to a composite intumescent and/or fire resistant barrier layer sections 150A, 150B, 150C and 150D which surrounds the solid wood core section 140. The composite intumescent and fire resistant barrier layer section 150A includes a first inner intumescent layer 152 being adjacent to and in contact with the solid wood core section 140, a second middle fire resistant barrier layer 154 being adjacent to and in contact with the first inner intumescent layer 152, a third outer intumescent layer 156 being adjacent to and in contact with the second middle fire resistant barrier layer 154 and a wood applique (veneer) 142 being adjacent and in contact with the third outer intumescent layer 156. The composite intumescent and fire resistant barrier layer section 150B includes a first inner intumescent layer 152 being adjacent to and in contact with the solid wood core section 140, a second middle fire resistant barrier layer 154 being adjacent to and in contact with the first inner intumescent layer 152, a wood applique (veneer) 142 being adjacent to and in contact with the second middle fire resistant barrier layer 154. The composite intumescent layer section 150C includes a first inner intumescent layer 152 being adjacent to and in contact with the solid wood core section 140, a second middle intumescent layer 158 being adjacent to and in contact with the first inner intumescent layer 152, and a wood applique (veneer) 142 being adjacent to and in contact with the second middle intumescent layer 158. The composite intumescent layer section 150D includes a first inner intumescent layer 152 being adjacent to and in contact with the solid wood core section 140, a second middle intumescent layer 158 being adjacent to and in contact with the first inner intumescent layer 152, and a wood applique (veneer) 142 being adjacent to and in contact with the second middle intumescent layer 158. The inner and middle intumescent layers 152 and 158 are made of PALUSOL P-210™ product being manufactured by the BASF Corporation of the USA. PALUSOL P-210™ is an intumescent panel consisting essentially of a core having sodium silicate, and a small portion of organic binder reinforced by glass fibers and wire mesh. A coating of epoxy resin is applied to each side of the core which protects the intumescent panel from atmospheric influences of carbon dioxide, water, and/or steam. The mass per unit area of the intumescent laminate (panel) layer 152 or 158 is in the range of 0.46 to 0.77 pounds per foot². The thickness of the intumescent laminate layer 152 or 156 is in the range 0.0590 inches to 0.906 inches. The second middle fire resistant barrier layer 154 is made of a FYRE ROC™ product being manufactured by the Goodrich Corporation, Engineered Polymer Products Division, of Jacksonville, Fla., U.S.A. The FYRE ROC™ panel is a laminate sheet consisting of a fire resistant metallo alumino silicate and stainless steel screen for forming a reinforced composite laminate sheet that has the ability to maintain excellent mechanical and physical properties at elevated temperatures up to 2000 degrees Fahrenheit, without significant smoke or toxicity emissions. The density of the fire resistant barrier laminate (sheet) layer 154 is 2.5±0.5 grams per cubic centimeter. The thickness of the fire resistant barrier laminate layer 154 is in the range of 0.020 to 0.050 inches (due to reinforcement thickness variability). The third outer intumescent layer 156 of the composite layer section 150A is made of a TECHNOFIRE 2000™ product manufactured by the TECHNICAL FIBRE PRODUCTS SUBSIDIARY in Newburgh, N.Y., U.S.A. The TECHNOFIRE 2000™ rigid sheet panel is a composite laminate sheet consisting of a core having rockwool fibers with chopped strand glass fibre reinforcement and a small portion of organic binder. A coating of epoxy resin is applied to each side of the core which protects the composite intumescent panel atmospheric influences of carbon dioxide, water and/or steam. The density of the composite intumescent laminate sheet layer 156 is in the range of 78.0 to 90.5 lbs/ft³. The mass per unit area of the intumescent laminate layer 156 is in the range of 0.333 to 0.386 pounds per foot². The intumescent laminate layer 156 has a maximum thickness of 1.3 mm (0.0512 inches). The intumescent laminate layer 156 upon exposure to heat and/or fire has an expansion ratio of 22 to 1 for importing linear gap seals between the fire retardant panel door 10 and door frame 30 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 10 and door frame 30. Wood molding 144 is applied to the exterior surface of the upper header 36, as shown in FIG. 1 of the drawings. The aforementioned wood applique 142, the composite layer sections 150A, 105B, 150C and 150D, and the solid wood core section 140 are laminated together under pressure P using an dual adhesive system consisting of a Simpson ISR 70-07 isocyanate adhesive A or an equivalent adhesive in order to form the jambs 32 and 34 and the upper header 36 of door frame 30.

The composite layer sections 150A, 150B, 150C and 150D of the jambs 32 and 34 and the upper header 36 expands in the presence of excessive heat and/or fire, such that the intumescent and fire resistant barrier material layer sections 150A, 150B, 150C and 150D closes and seals the perimeter of the fire retardant panel door 10 within the jambs 32 and 34 and upper header 36 of the door frame 30 to also prevent the spread of the excessive heat and/or fire through the fire retardant panel door 10 and door frame 30, as shown in FIG. 1.

Additionally, as shown in FIGS. 3, 4 and 5, the jambs 32 and 34 further include a pair of metal L-shaped beads 168 made from 16 gauge galvanized steel being positioned at the corners 169a and 169b of jambs 32 and 34, respectively. The metal L-shaped beads 168 each include a first end section 168f and a second end section 168s. Each of the second end sections 168s of metal L-shaped beads 168 are further positioned and placed between the second middle fire resistant barrier layer 154 and the third outer intumescent layer 156, as shown in FIGS. 3, 4 and 5 of the drawings. Each of the first end sections 168f of metal L-shaped beads 168 are further positioned and placed between such that they are in contact with and adjacent to the second middle intumescent layer 158 and the wood applique (veneer) 142 of composite layer end sections 150C and 150D of jambs 32 and 34, respectively. The aforementioned metal L-shaped beads 168 are used for rigidity and retention of the second middle fire resistant barrier layer 154 and the third outer intumescent layer 156 together and in conjunction with each other to form a partial exoskeleton layer Epx, as shown in FIGS. 3, 4 and 5 of the drawings, in order to further strengthened jambs 32 and 34, respectively. Each of the metal L-shaped beads 168 are fastened to the composite end sections 150C and 150D of jambs 32 and 34, respectively, by brads 120n or staples 120s, as shown in FIGS. 5 and 10.

The fire retardant panel door 10 and door frame 30 of the first embodiment of the present invention further includes a heat activated door pin assembly 170, as shown in FIGS. 2, 2A and 2B, for securing and holding a free corner C_F of the stile 14 of the fire retardant panel door 10 in place while the intumescent layers of the stiles 12, 14 and rails 16, 18 react from excessive heat and/or fire. The heat activated door pin assembly 170 includes a substantially cylindrically-shaped housing member 172 having a pin opening 174 for receiving a movable and hollow door pin 180 therein. The housing member 172 further includes a curved outer wall 176 and a bottom wall 177 for forming an interior compartment 178. The hollow pin 180 includes an internal compressible spring 182 coiled about a threaded rod 184. The compressible spring 182 includes a first lower end 182f and a second upper end 182s. Threaded rod 184 includes a proximal end 184p and a distal end 184d. The proximal end 184p of threaded rod 184 is connected to the first lower end 182f of compressible spring 182 and is held in place by washer 186 and hex nut 188. The distal end 184d of threaded rod 184 includes a fusible solder link 190. The fusible solder link 190 melts at 117° F. allowing the internal compressible spring 182 to eject the movable door bolt pin 180 within a strike plate opening 192 of a strike plate 194, such that the movable door bolt pin 180 resides within an upper header bolt opening 36h of upper header 36. The strike plate 194 also includes mounting openings 195 for receiving mounting screws 196 therein for attaching the strike plate 194 to the upper header 36, as shown in FIGS. 2A and 2B of the drawings. Further, the bottom wall 177 of interior compartment 178 of the housing member 172 includes a pair of circular intumescent pads 198a and 198b. The intumescent pads 198a and 198b upon exposure to excessive heat and/or fire expands rapidly (22 times the original thickness) and locks the movable door bolt pin 180 permanently within the upper header bolt opening 36h. Thus, preventing any movement or buckling of the free corner C_F of the fire retardant panel door 10 relative to the door frame 30. Intumescent pads 198a and 198b are made form TECHNOFIRE 2000™ composite laminate sheets as previously described in the above preferred embodiment. Housing member 172 is made of copper metal and the movable hollow door bolt pin 180 is made of brass metal.

Second Embodiment 200

A double door assembly 200 and door frame 230 of the second embodiment of the present invention is represented in detail by FIGS. 11 through 23 of the patent drawings. The double door assembly 200 includes a first fire retardant panel door 210, and a second fire retardant panel door 410 being hingedly connected to a double door frame 230. The first and second fire retardant panel doors 210 and 410, and double door frame 230 are used to fireproof an area and to prevent fire from spreading to other areas within a home dwelling, a commercial building, or an industrial plant. Fire retardant panel doors 210 and 410 are hingedly connected between a left and right door jambs 232 and 234 and positioned below an upper header 236, as depicted in FIG. 11 of the drawings. Jambs 232 and 234 include an interior wall surface 233 and 235, respectfully and upper header 236 includes an interior wall surface 237.

Fire retardant panel door 210 includes stiles 212 and 214, rails 216 and 218, and a center panel 220, as shown in FIGS. 11 and 13 through 18 of the drawings. The fire retardant panel door 210 is hingedly connected to one section 230A of the door frame 230, as depicted in FIGS. 11, 13, and 14, such that the panel door 210 is hingedly connected to the left door jamb 232 and positioned below section 230A of the upper header 236, as depicted in FIGS. 8 and 9 of the drawings. As shown in FIGS. 12 and 19 through 21, the stiles 212 and 214 and rails 216 and 218 have a solid core section 240 formed of a yellow poplar microllam of wood material, and the like. Wood applique 242 (i.e., oak, maple, walnut, etc.) is applied to a composite intumescent and fire resistant layer section 250 which partially surrounds the solid wood core section 240 on sides 251 and 253, respectively. The composite intumescent and fire resistant layer section 250 includes a first inner intumescent layer 252 being adjacent to and in contact with the solid wood core section 240, a second middle fire resistant barrier layer 254 being adjacent to and in contact with the first inner intumescent layer 252, and a third outer intumescent layer 256 being adjacent to and in contact with the second middle fire resistant barrier layer 254. The inner and outer intumescent layers 252 and 256 of sides 251 and 253 are made of PALUSOL P-210™ product being manufactured by the BASF Corporation of the USA. PALUSOL P-210™ is an intumescent panel consisting essentially of a core having sodium silicate, and a small portion of organic binder reinforced by glass fibers and having the addition of wire mesh therein. A coating of epoxy resin is applied to each side of the core which protects the intumescent panel from atmospheric influences of carbon dioxide, water, and/or steam. The mass per unit area of the intumescent laminate (panel) layers 252 or 256 is in the range of 0.46 to 0.77 pounds per foot². The thickness of the intumescent laminate layers 252 or 256 is in the range 0.0590 inches to 0.0906 inches. The second middle layer fire resistant barrier 254 is made of a FYRE ROC™ (FR-1001) product being manufactured by the Goodrich Corporation, Engineered Polymer Products Division, of Jacksonville, Fla., U.S.A. The FYRE ROC™ panel is a laminate sheet consisting of a fire resistant metallo alumino silicate and stainless steel screen layers for forming a reinforced composite laminate sheet that has the ability to maintain excellent mechanical and physical properties at elevated temperatures up to 2000 degrees Fahrenheit, without significant smoke or toxicity emissions. The density of the laminate fire resistant barrier (sheet) layer 254 is 2.5±0.5 grams per cubic centimeter. The thickness of the laminate fire resistant barrier layer 254 is in the range of 0.020 to 0.050 inches (due to reinforcement thickness variability).

The wood applique 242 is adjacent to and in contact with the third outer intumescent layer 256. Wood molding 244 is applied to the exterior surface of stiles 212 and 214, rails 216 and 218, and center panel 220, as shown in FIG. 11 of the drawings. The aforementioned wood applique 242, intumescent layers 252, 254, and 256, and the solid wood core section 240 are laminated together under pressure P using a dual adhesive system consisting of a Simpson ISR 70-07 isocyonate adhesive A or an equivalent adhesive in order to form the laminated stiles 212 and 214 and rails 216 and 218, respectively.

As shown in FIGS. 11, and 13 through 18, the stiles 212 and 214 and rails 216 and 218 also include inner and outer ends 255 and 257, respectively. The inner end 255 includes a first inner intumescent end layer 258 being adjacent to and in contact with the solid wood core section 240, and a second middle intumescent end layer 260 being adjacent to and in contact with the first inner intumescent layer 258. The first and second intumescent end layers 258 and 260 of inner end 255 are made of the PALUSOL™ P-210 product as previously described. The outer end 257 includes a first inner intumescent end layer 262 being adjacent to and in contact with the solid wood core section 240, a second middle intumescent end layer 264 being adjacent to and in contact with the first inner intumescent end layer 262, a third outer intumescent end layer 266 being adjacent to and in contact with the second middle intumescent end layer 264 and the wood applique (veneer) 242 being adjacent to and in contact with the third outer intumescent end layer 266. The first inner intumescent end layer 262 is made of the PALUSOL™ P-210 product as previously described. The second and third intumescent end layers 264 and 266 are made of a TECHNOFIRE 2000™ product manufactured by the TECHNICAL FIBRE PRODUCTS SUBSIDIARY in Newburgh, N.Y., U.S.A. The TECHNOFIRE 2000™ rigid sheet panel is a composite laminate sheet consisting of a core having rockwool fibers with chopped strand glass fibre reinforcement and a small portion of organic binder. A coating of epoxy resin is applied to each side of the core which protect the composite intumescent panel from atmospheric influences of carbon dioxide, water and/or steam. The density of the composite intumescent laminate sheet end layers 264 or 266 is in the range of 78.0 to 90.5 5 lbs/ft³ (1250 to 1450 kg/m³). The intumescent laminate end layers 264 or 266 has a maximum thickness of 1.3 mm (0.0512 inches). The mass per unit area of the intumescent laminate end layers 264 or 266 is in the range of 0.333 to 0.386 pounds per foot². The intumescent laminate end layers 264 or 266 upon exposure to heat and/or fire has expansion ratio of 22:1 for imparting linear gap seals between the fire retardant panel door 10 and door frame 30 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 10 and door frame 30.

Additionally, as shown in FIGS. 11 and 13 through 18, the stiles 212 and 214 and rails 216 and 218 further include a plurability of metal L-shaped beads 268 made from 16 gauge galvanized steel being positioned at the corners 269a, 269b, 269c and 269d of the stiles 212 and 214, and rails 216 and 218. The metal L-shaped beads 268 each include a first end section 268f and a second end section 268s. Each of the second end sections 268s of metal L-shaped beads 268 are further positioned and placed between the second middle fire resistant barrier layer 254 and the third outer intumescent layer 256, as shown in FIGS. 11 and 13 through 18 of the drawings. One pair of the first end sections 268f at the inner end 255 are further positioned and placed in contact with and adjacent to the second middle end layer 260. The other pair of the first end sections 268f at the outer end 257 are further positioned and placed between the first inner intumescent end layer 262 and the second middle intumescent end layer 264. The aforementioned metal L-shaped beads 268 are used for rigidity and retention of the second middle fire resistant barrier layers 254 and the third outer intumescent layers 256 together and in conjunction with each other to form an exoskeleton layer E_x, as shown in FIGS. 11 and 13 through 18 of the drawings, in order to further strengthen and tie together stiles 212 and 214 and rails 216 and 218, respectively. Each of the metal L-shaped beads 268 are fastened at the inner and outer ends 255 and 257 of the stiles 212, 214 and rails 216, 218 by brads 120n and staples 120s, respectively, as shown in FIGS. 7 and 8.

Center panel 220 has edges 261, 263, 265 and 267. The center panel 220 is formed from a composite laminate structure 270. The composite laminate structure 270 includes outer wood sections 272 and 276 and sandwiched there between is an interior center intumescent section 274, as depicted in FIGS. 19 and 20. The interior center composite intumescent section 274 includes a first outer intumescent layer 278, a second inner fire resistant barrier intumescent layer 280, a third middle intumescent layer 282, a fourth middle intumescent layer 284, a fifth inner fire resistant barrier layer 286, and a sixth outer intumescent layer 288. The first outer, third middle, fourth middle, and sixth outer intumescent layers 278, 282, 284, and 288 are made of the PALUSOL™ P-210 product, as previously described. The second and fifth inner fire resistant barrier layers 280 and 286, are made of the FYRE ROC™ fire resistant barrier intumescent laminate sheet, as previously described. The aforementioned outer wood sections 272, 276 and the intumescent and fire resistant barrier layers 278, 280, 282, 284, 286 and 288 are laminated together under pressure P using an adhesive system consisting of a Simpson ISR 70-07 isocyante adhesive A or an equivalent adhesive in order to form the laminated center panel 220.

Tongue and groove joints 290 and 292 are used to connect center panel 220 to stiles 212 or 214, respectively, and tongue and groove joints 294 and 296 are used to connect center panel 220 to rails 216 or 218, respectively, as depicted in FIGS. 19 to 21 of the drawings. Tongue and groove joints 298 and 300 are used to connect rails 216 or 218 to stiles 212 or 214, respectively, as shown in FIG. 10A of the drawings. As shown in FIG. 19, the tongue and groove joints 290 and 292 include air gaps 302 and 304 for expansion of the intumescent material layers 278, 282, 284 and 288 in the presence of excessive heat and/or fire, such that the intumescent material layers 278, 282, 284 and 288 close and seal the air gaps 304 within the fire retardant panel door 210 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 210 and door frame 230. Further, the tongue and groove joints 294 and 296, as depicted in FIG. 20, also include air gaps 308 for expansion of the intumescent material layers 278, 282,284 and 288 in the presence of excessive heat and/or fire, such that the intumescent material layers 278, 282, 284 and 288 close and seal the air gaps 308 within the fire retardant panel door 210 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 210 and door frame 230. Additionally, the tongue and groove joints 298 and 300, as shown in FIGS. 12 and 13, include air gaps 312 for expansion of the intumescent end layers 258 and 260 in the presence of excessive heat and/or fire, such that the intumescent end layers 258 and 260 close and seal the air gaps 312 within the fire retardant panel door 210 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel 210 and door frame 230. Also, the tongue and groove joints 290 and 292 and 294 and 296, are attached to each other using a staple 120s or nail 120n, respectfully, as shown in FIGS. 19 and 20 of the drawings. Further, each of the rails 216 and 218 and stiles 212 and 214 include a dowel groove 322, 323, 324 and 325, respectfully, for receiving a wooden dowel 326 therein, for additionally joining together the rails 216 and 218 to the stiles 212 and 214, respectfully, as shown in FIGS. 14 and 15 of the drawings. The dowels 326 are held in place within dowel grooves 322, 323, 324 and 325 with appropriate wood glue G, as depicted in FIGS. 14 and 15.

As shown in FIGS. 13 through 18 and 23, the jambs 232 and 234, and upper head 236 of door frame 230 include a core section 340 formed of wood materials, such as oak, maple, walnut, pine, poplar and the like. Wood applique 342 (i.e., oak, maple, walnut, etc.) is applied to a composite intumescent and/ layer section 350 which surrounds the solid wood core section 340. The composite intumescent layer section 350A includes a first inner intumescent layer 352 being adjacent to and in contact with the solid wood core section 340, a second middle intumescent layer 354 being adjacent to and in contact with the first inner intumescent layer 352, and a third outer intumescent layer 356 being adjacent to and in contact with the second middle intumescent layer 354 and a wood applique (veneer) 342 being adjacent and in contact with the third outer intumescent layer 356. The composite intumescent and fire resistant barrier layer section 350B includes a first inner intumescent layer 352 being adjacent to and in contact with the solid wood core section 340, a second middle fire resistant barrier layer 354 being adjacent to and in contact with the first inner intumescent layer 352, a wood applique (veneer) 342 being adjacent to and in contact with the second middle fire resistant barrier layer 354. The composite intumescent layer section 350C includes a first inner intumescent layer 352 being adjacent to and in contact with the solid wood core section 340, a second middle intumescent layer 358 being adjacent to and in contact with the first inner intumescent layer 352, and a wood applique (veneer) 342 being adjacent to and in contact with the second middle intumescent layer 358. The composite intumescent layer section 350D includes a first inner intumescent layer 352 being adjacent to and in contact with the solid wood core section 340, a second middle intumescent layer 358 being adjacent to and in contact with the first inner intumescent layer 352, and a wood applique (veneer) 342 being adjacent to and in contact with the second middle intumescent layer 358. The inner and outer intumescent layer 352 and 358 are made of PALUSOL P-210™ product being manufactured by the BASF Corporation of the USA. PALUSOL P-210™ is an intumescent panel consisting essentially of a core having sodium silicate, and a small portion of organic binder reinforced by glass fibers and wire mesh. A coating of epoxy resin is applied to each side of the core which protects the intumescent panel from atmospheric influences of carbon dioxide, water, and/or steam. The mass per unit area of the intumescent laminate (panel) layer 352 or 358 is in the range of 0.46 to 0.77 pounds per foot². The thickness of the intumescent laminate layer 352 or 356 is in the range 0.0590 inches to 0.906 inches. The second middle fire resistant barrier layer 354 is made of a FYRE ROC™ product being manufactured by the Goodrich Corporation, Engineered Polymer Products Division, of Jacksonville, Fla., U.S.A. The FYRE ROC™ panel is a laminate sheet consisting of a fire resistant metallo silicate and stainless steel screen for forming a reinforced composite laminate sheet that has the ability to maintain excellent mechanical and physical properties at elevated temperatures up to 2000 degrees Fahrenheit, without significant smoke or toxicity emissions. The density of the fire resistant barrier laminate (sheet) layer 354 is 2.5±0.5 grams per cubic centimeter. The thickness of the laminate intumescent layer 354 is in the range of 0.020 to 0.050 inches (due to reinforcement thickness variability). The third outer intumescent layer 356 of the composite layer section 350A is made of a TECHNOFIRE 2000™ product manufactured by the TECHNICAL FIBRE PRODUCTS SUBSIDIARY in Newburgh, N.Y., U.S.A. The TECHNOFIRE 2000™ rigid sheet panel is a composite laminate sheet consisting of a core having rockwool fibers with chopped strand glass fibre reinforcement and a small portion of organic binder. A coating of epoxy resin is applied to each side of the core which protects the composite intumescent panel atmospheric influences of carbon dioxide, water and/or steam. The density of the composite intumescent laminate sheet layer 356 is in the range of 78.0 to 90.5 lbs/ft³. The mass per unit area of the intumescent laminate layer 356 is in the range of 0.333 to 0.386 pounds per foot². The intumescent laminate layer 356 has a maximum thickness of 1.3 mm (0.0512 inches). The intumescent laminate layer 356 upon exposure to heat and/or fire has an expansion ratio of 22 to 1 for importing linear gap seals between the fire retardant panel door 210 and door frame 230 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 210 and door frame 230. Wood molding 344 is applied to the exterior surface of the upper header 236, as shown in FIGS. 8 and 9 of the drawings. The aforementioned wood applique 342, the composite layer sections 350A, 350B, 350C and 350D, and the solid wood core section 340 are laminated together under pressure P using an dual adhesive system consisting of a Simpson ISR 70-07 isocyanate adhesive A or an equivalent adhesive in order to form the jambs 232, 234 and the upper header 236 of door frame 230, as depicted in FIG. 23.

The composite layer sections 350A, 350B, 350C and 350D of the jambs 232 and 234 and upper header 236 expand in the presence of excessive heat and/or fire, such that the intumescent and fire resistant barrier material layer sections 350A, 350B, 350C and 350D closes and seals the perimeter of the fire retardant panel door 210 within the jambs 232 and 234 and upper header 236 of the door frame 230 to also prevent the spread of the excessive heat and/or fire through the fire retardant panel door 210 and door frame 230.

Additionally, as shown in FIGS. 11, 13 through 18, the jambs 232 and 234 further include a pair of metal L-shaped beads 368 made from 6 gauge galvanized steel being positioned at the corners 369a to 369d of jambs 232 and 234, respectively. The metal L-shaped beads 368 each include a first end section 368f and a second end section 368s. Each of the second end sections 368s of metal L-shaped beads 368 are further positioned and placed between the second middle fire resistant barrier layer 356 and the third outer intumescent layer 356, as shown in FIGS. 11 and 13 through 18 of the drawings. Each of the first end sections 368f of metal L-shaped beads 368 are further positioned in contact with and adjacent to the second middle intumescent layer 358 and the wood applique (veneer) 342 of composite layer end sections 350C and 350D of jambs 232 and 234, respectively. The aforementioned metal L-shaped beads 368 are used for rigidity and retention of the second middle fire resistant barrier layer 354 and the third outer intumescent layer 356 together and in conjunction with each other to form a partial exoskeleton layer Epx, as shown in FIGS. 11 and 13 through 18 of the drawings, in order to further strengthened jambs 232 and 234, respectively. Each of the metal L-shaped beads 368 are fastened to the composite end sections 350C and 350D of jambs 232 and 234, respectively, by brads 120n or staples 120s, as shown in FIGS. 13, 14 and 23.

The fire retardant panel door 210 and door frame section 230A of door frame 230 of the second embodiment of the present invention further includes a standard mechanical flush or dead bolt assembly 370, as shown in FIGS. 12 and 12A, for securing and holding a first free corner C_F1 of the fire retardant panel door 21 in place while the intumescent layers of the stiles 212, 214 and rails 16, 18 react from excessive heat and/or fire. The flush or dead bolt assembly 370 is positioned within stile 214 as shown in FIGS. 12 and 12A of the drawings. The dead bolt assembly 370 includes a housing member 372 for receiving a dead bolt 374. Dead bolt 374 is received within a dead bolt receiving member 376 positioned within the upper header 236 of the door frame section 230A. The aforementioned dead bolt assembly 370 presents any movement or buckling of the first free corner C_F1 of the fire retardant panel door 210 relative to the door frame section 230A of door frame 230.

Fire retardant panel door 410 includes stiles 412 and 414, rails 416 and 418, an upper panel 420, a lower panel 422, a first raised panel 423, and a second raised panel 424, as shown in FIGS. 11 and 13 through 18 of the drawings. The fire retardant panel door 410 also includes a first mullion 426 separating the upper panel 420 from the lower panel 422, a second mullion 427 separating the lower panel 422 from the first raised panel 423, and a third mullion 428 separating the first raised panel 423 from the second raised panel 424. The fire retardant panel door 410 is hingedly connected to the other section 230B of the door frame 430, as depicted in FIG. 11, such that the panel door 410 is hingedly connected to the right door jamb 234 and positioned below a section 230B of the upper header 236, as depicted in FIGS. 11 and 12 of the drawings.

As shown in FIGS. 11, 12 and 19 through 21, the stiles 412 and 414, rails 416 and 418, and mullions 426, 427, and 428 have a solid core section 440 formed of a yellow poplar microllam wood material, and the like. Wood applique 442 (i.e., oak, maple, walnut, etc.) is applied to a composite intumescent and fire resistant layer section 450 which partially surrounds the solid wood core section 440 on sides 451 and 453, respectively. The composite intumescent and fire resistant layer section 450 includes a first inner intumescent layer 452 being adjacent to and in contact with the solid wood core section 440, a second middle fire resistant barrier layer 454 being adjacent to and in contact with the first inner intumescent layer 452, and a third outer intumescent layer 456 to being adjacent and in contact with the second middle fire resistant barrier layer 454. The inner and outer intumescent layers 452 and 456 of sides 451 and 453 are made of PALUSOL P-210™ product being manufactured by the BASF Corporation of the USA. PALUSOL P-210™ is an intumescent panel consisting essentially of a core having sodium silicate, and a small portion of organic binder reinforced by glass fibers and wire mesh. A coating of epoxy resin is applied to each side of the core which protects the intumescent panel from atmospheric influences of carbon dioxide, water, and/or steam. The mass per unit area of the intumescent laminate (panel) layers 452 or 456 is in the range of 0.46 to 0.77 pounds per foot². The thickness of the intumescent laminate layers 452 or 456 is in the range 0.0590 inches to 0.0906 inches. The second middle fire resistant barrier layer 454 is made of a FYRE ROC™ (FR-1001) product being manufactured by the Goodrich Corporation, Engineered Polymer Products Division, of Jacksonville, Fla., U.S.A. The FYRE ROC™ panel is a laminate sheet consisting of a fire resistant metallo alumino silicate and stainless steel screen reinforced composite laminate sheet that has the ability to maintain excellent mechanical and physical properties at elevated temperatures up to 2000 degrees Fahrenheit, without significant smoke or toxicity emissions. The density of the laminate fire resistant barrier (sheet) layer 454 is 2.5±0.5 grams per cubic centimeter. The thickness of the laminate first resistant barrier layer 454 is in the range of 0.020 to 0.050 inches (due to reinforcement thickness variability).

The wood applique 442 is adjacent to and in contact with the third outer intumescent layer 456. Wood molding 444 is applied to the exterior surface of stiles 412 and 414, rails 416 and 418, mullions 426, 427, and 428, and panels 420, 422, 423, and 424, as shown in FIGS. 8 and 9 of the drawings. The aforementioned wood applique 442, intumescent layers 452, 454, and 456, and the solid wood core section 440 are laminated together under pressure P using an adhesive system A consisting of a Simpson ISR 70-07 isocyanate adhesive A or an equivalent adhesive in order to form the laminated stiles 412 and 414, rails 416 and 418, and mullions 426, 427, and 428, respectively, as depicted in FIGS. 19 and 20.

As shown in FIGS. 11, 13, through 18, the stiles 412 and 414 rails 416 and 418 and mullions 426, 427 and 428 also include inner and outer ends 455 and 457, respectively. The inner end 455 includes a first inner intumescent end layer 458 being adjacent to and in contact with the solid wood core section 440, and a second middle intumescent end layer 460 being adjacent to and in contact with the first inner intumescent layer 458. The first and second intumescent end layers 458 and 460 of inner end 455 are made of the PALUSOL™ P-210 product as previously described. The outer end 457 includes a first inner intumescent end layer 462 being adjacent to and in contact with the solid wood core section 440, a second middle intumescent end layer 464 being adjacent to and in contact with the first inner intumescent end layer 462, a third outer intumescent end layer 466 being adjacent to and in contact with the second middle intumescent end layer 464 and the wood applique (veneer) 442 being adjacent to and in contact with the third outer intumescent end layer 466. The first inner intumescent end layer 462 is made of the PALUSOL™ P-210 product as previously described. The second and third intumescent end layers 464 and 466 are made of a TECHNOFIRE 2000™ product manufactured by the TECHNICAL FIBRE PRODUCTS SUBSIDIARY in Newburgh, N.Y., U.S.A. The TECHNOFIRE 2000™ rigid sheet panel is a composite laminate sheet consisting of a core having rockwool fibers with chopped strand glass fibre reinforcement and a small portion of organic binder. A coating of epoxy resin is applied to each side of the core which protect the composite intumescent panel from atmospheric influences of carbon dioxide, water and/or steam. The density of the composite intumescent laminate sheet end layers 464 or 466 is in the range of 78.0 to 90.5 5 lbs/ft³ (1250 to 1450 kg/m³). The intumescent laminate end layers 464 or 466 has a maximum thickness of 1.3 mm (0.0512 inches). The mass per unit area of the intumescent laminate end layers 464 or 466 is in the range of 0.333 to 0.386 pounds per foot². The intumescent laminate end layers 464 or 466 upon exposure to heat and/or fire has expansion ratio of 22:1 for imparting linear gap seals between the fire retardant panel door 10 and door frame 30 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 410 and door frame section 230B of door frame 230.

Additionally, as shown in FIGS. 11, 13 through 18, the stiles 412 and 414 and rails 416 and 418 further include a plurability of metal L-shaped beads 468 made from 16 gauge galvanized steel being positioned at the corners 469a, 469b, 469c and 469d of the stiles 412 and 414, and rails 416 and 418. The metal L-shaped beads 468 each include a first end section 468f and a second end section 468s. Each of the second end sections 468s of metal L-shaped beads 468 are further positioned and placed between the second middle fire resistant barrier layer 454 and the third outer intumescent layer 456, as shown in FIGS. 11, 13 through 18 of the drawings. One pair of the first end sections 468f at the inner end 455 are further positioned and placed in contact with and adjacent to the second middle end layer 460. The other pair of the first end sections 468f at the outer end 457 are further positioned and placed between the first inner intumescent end layer 462 and the second middle intumescent end layer 464. The aforementioned metal L-shaped beads 468 are used for rigidity and retention of the second middle fire resistant barrier layers 454 and the third outer intumescent layers 456 together and in conjunction with each other to form an exoskeleton layer E_x, as shown in FIGS. 11, 13 through 18 of the drawings, in order to further strengthen stiles 412 and 414 and rails 416 and 418, respectively. Each of the metal L-shaped beads 68 are fastened at the inner and outer ends 455 and 457 of the stiles 412, 414 and rails 416, 418 by brads 120n and staples 120s, respectively, as shown in FIGS. 7 and 8.

Upper panel 420 has edges 461, 463, 465 and 467, and the lower panel has edges 563, 565, 567, and 569. The panels 420, 422, 423, and 424 are formed from a composite laminate structure 470, as shown in FIGS. 13 to 18 and 21 of the drawings. The composite laminate structure 470 includes outer wood sections 472 and 476 and an interior center intumescent section 474 sandwiched therebetween. The interior center intumescent section 474 includes a first outer intumescent layer 478, a second inner fire resistant barrier layer 480, a third middle intumescent layer 482, a fourth middle intumescent layer 484 a fifth inner fire resistant barrier layer 486, and a sixth outer intumescent layer 488. The first outer, third middle, fourth middle, and sixth outer intumescent layers 478, 482, 484, and 488 are made of the PALUSOL™ P-210 product as previously described. The second and fifth fire resistant barrier layers 480 and 486 are made of the FYRE ROC™ fire resistant barrier laminate sheet, as previously described. The aforementioned outer wood sections 472, 476 and the intumescent and fire resistant barrier layer 478, 480, 482, 484, 486 and 488 are laminated together under pressure P using an adhesive system consisting of a Simpson ISR 70-07 isocyanate adhesive A or an equivalent adhesive in order to form the laminated panels 428, 422, 423, and 424, respectively, as shown in FIGS. 19, 20, and 22 of the drawings.

Tongue and groove joints 490 and 492 are used to connect upper panel 420 to stiles 412 or 414, respectively, and tongue and groove joints 494 and 496 are used to connect upper panel 420 to rail 416, as depicted in FIGS. 12 and 20 of the drawings. Tongue and groove joints 498 and 500 are used to connect rails 416 or 418 to stiles 412 or 414, respectively, as shown in FIG. 14 of the drawings. Additionally, tongue and groove joints 514 and 516 are used to connect the first mullion 426 to stiles 412 or 414, as well as the first mullion 426 to upper panel 420, as depicted in FIG. 15. As shown in FIGS. 13, 19 and 19B the tongue and groove joints 490 and 492 include air gaps 504 for expansion of the intumescent material layers 478, 482, 484, and 488 in the presence of excessive heat and/or fire, such that the intumescent material layers 478, 482, 484, and 488 close and seal the air gaps 504 within the fire retardant panel door 410 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 410 and door frame 430. Further, the tongue and groove joints 494 and 496, as shown in FIGS. 14, 20A, 20B and 20C also include air gaps 508 for expansion of the intumescent material layers 478, 482, 484, and 488 in the presence of excessive heat and/or fire, such that the intumescent material layers 478, 482, 484, and 488 close and seal the air gaps 508 within the fire retardant panel door 410 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 410 and door frame 230. Also, the tongue and groove joints 514 and 516 include air gaps 520 for expansion of the intumescent material layers 478, 482, 484, and 488 in the presence of excessive heat and/or fire, such that the intumescent material layers 478, 482, 484, and 488 close and seal the air gaps 520 within the fire retardant panel door 410 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel door 410 and door frame 230. Additionally, the tongue and groove joints 498 and 500 as shown in FIGS. 12 and 13 include air gaps 512 for expansion of the intumescent end layers 458 and 460 in the presence of excessive heat and/or fire, such that the intumescent end layers 458 and 460 close and seal the air gaps 512 within the fire retardant panel door 410 in order to prevent the spread of excessive heat and/or fire through the fire retardant panel 410 and door frame 230. Also, the tongue and groove joints 490 and 492, 494 and 496, and 514 and 516 are attached to each other using a staple 120s or nail 120n, respectively, as shown in FIGS. 11, 20, and 21 of the drawings. Further, each of the rails 416 and 418, and stiles 412 and 414 include a dowel groove 522, 523, 524 and 525, respectfully, for receiving the wooden dowel 326. Therein, for additionally joining together the rails 416 and 418 to the stiles 412 and 414, respectfully, as shown in FIGS. 14 and 15. The dowels 526 are held in place within dowel grooves 522, 523, 524 and 525 with appropriate wood glue G, as shown in FIGS. 14 and 15.

The fire retardant panel door 410 and door frame 230 of the second embodiment 200 of the present invention further includes a heat activated door pin assembly 570, as shown in FIGS. 12, 12B, 12C and 12D, for securing and holding a second free corner C_F2 of the fire retardant panel door 410 in place (to present buckling of free corner C_F2) while the intumescent layers of the stiles 412, 414 and rails 416, 418 react from excessive heat and/or fire. The heat activated door pin assembly 570 includes a substantially cylindrically-shaped housing member 572 having a pin opening 574 for receiving a movable and hollow door pin 580 therein. The housing member 572 further includes a curved outer wall 576 and a bottom wall 577 for forming an interior compartment 578. The hollow pin 580 includes an internal compressible spring 582 coiled about a threaded rod 584. The compressible spring 582 includes a first lower end 582f and a second upper end 582s. Threaded rod 584 includes a proximal end 584p and a distal end 584d. The proximal end 584p of threaded rod 584 is connected to the first lower end 582f of compressible spring 582 and is held in place by washer 586 and hex nut 588. The distal end 584d of threaded rod 584 includes a fusible solder link 590. The fusible solder link 590 melts at 117° F. allowing the internal compressible spring 582 to eject the movable door bolt pin 580 withing a strike plate opening 592 of a strike plate 594, such that the movable door bolt pin 580 resides within an upper header bolt opening 236h of upper header 236. The strike plate 594 also includes mounting openings 595 for receiving mounting screws 596 therein for attaching the strike plate 594 to the upper header 236, as shown in FIGS. 12B and 12C of the drawings. Further, the bottom wall 577 of interior compartment 578 of the housing member 572 includes a pair of circular intumescent pads 598a and 598b. The intumescent pads 598a and 598b upon exposure to excessive heat and/or fire expands rapidly (23 times the original thickness) and locks the movable door bolt pin 580 permanently within the upper header bolt opening 236h. Thus, preventing any movement or buckling of the second free corner C_F2 of the fire retardant panel door 410 relative to the door frame 230. Intumescent pads 598a and 598b are made form TECHNOFIRE 2000™ composite laminate sheets as previously described in the above preferred embodiment. Housing member 572 is made of copper metal and the movable hollow door bolt pin 580 is made of brass metal.

It is understood that the heat activated door pin assembly 570′ and 570″ can also be positioned at other locations, such as along the vertical axis of stile 412, as shown in FIG. 12. In this manner, when the heat activated door pin assemblies (570′ and 570″ ) react to excessive heat and/or fire, they cause the door panels 210 and 410 to lock together to prevent any movement or buckling of the door panels 210 and 410 relative to the door frame 230.

The fire retardant panel door 410 and door frame 230 of the second embodiment 200 of the present invention also includes a heat activated door hook or door latch assembly 610, as shown in FIGS. 12, 12E, 12F, 12G, 12H, 12I and 12J for securing and holding a second free corner C_F2 of the fire retardant panel door 410 in place (to prevent buckling of the free corner C_F2) while the intumescent layers of the stiles 412, 414 and rails 416, 418 react from excessive heat and/or fire. The heat activated door hook assembly 610 includes a substantially rectangular-shaped housing member 612 having a top wall 614 in the form of a strike plate, a bottom wall 616, a front wall 618, a rear wall 620, a left side wall 622, a right side wall 624 for forming an interior compartment 626. Strike plate 614 includes a hook/latch opening 628 for receiving a movable door hook or door latch member 630 therethrough. Strike plate 614 further includes opposing ends 632a and 632b having mounting openings 634a and 634b therethrough for receiving mounting screws 636 therein. The strike plate 614 also includes a solder link opening 638 for receiving a fusible solder link 640 therethrough. The front and rear walls 618 and 620 include shaft openings 642 and 644 therethrough for receiving a shaft member 646 therein. The bottom wall 616 includes a rectangular opening 648 for accessing the door hook member 630. The door hook member 630 includes a hook or latch section 650, a shaft hook opening 645 for receiving the shaft member 646 therethrough, a round end section 652, a front wall 654 and a rear wall 656. The door hook member 630 further includes an internal compressible spring 658 having a first spring end 660 and a second spring end 662 being integrally attached to the front wall 654 of the hook member 630 and adjacent to the shaft hook opening 652, as depicted in FIGS. 12D and 12E of the drawings. The fusible solder link 640 includes a first solder link end 664 and a second solder link end 666. Side wall 624 includes a pin opening 668 for receiving the first spring end 660 therethrough in order to hold the compressible spring 658 in place on side wall 624, as shown in FIG. 12D. The hook member 630, the attached compressible spring 658 and the fixed shaft member 646 are all positioned within the interior compartment 626 of the housing member 612. The first solder link end 664 of the fusible solder link 640 is detachably connected to the solder link opening 638 and the second solder link end 666 of the fusible solder link 640 is connected to the second spring end 662 of compressible spring 658 such that the heat activated door hook assembly 610 is an unexpanded configuration and tensioned state C₁, as shown in FIG. 12D, and is readied for activation by heat or fire. In an alternate design configuration, the second solder link end 666 of the fusible solder link 640 is connected to the front wall 654 of the round end section 652 of door hook member 630 such that the heat activated door hook assembly 610 is also in the tensioned state C₁. The fusible solder link 640 melts at 117° F. allowing the second spring end 662 of compressible spring 658 to rotatably move in a clockwise motion R_C, such that the hook section 650 of the door hook member 630 is then moved to an untensioned state C₂. The shaft hook opening 652 of the door hook member 630 pivots on the fixed shaft member 646, where then the hook section 650 rotatably moves within an upper strike plate opening 672 of an upper strike plate 670. The upper strike plate 670 includes mounting openings 674a and 674b for receiving mounting screws 636 therethrough for attaching permanently to the upper strike plate 670 to the upper header 236, as shown in FIGS. 12D and 12E of the drawings. The housing member 612 is made from brass or copper materials.

OPERATION OF THE PRESENT INVENTION

In operation, when fire or excessive heat occurs, the intumescent materials expand and provide closing and sealing of all the tongue and groove joints within panel doors 10, 210, and 410, respectively, of the first and second embodiments. This includes also the closing and sealing of the panels, stiles, rails, and/or mullions, as well as perimeter edges of the fire retardant panel doors 10, 210, and 410 within the door frames 30 and 230, respectively, thus preventing the spread of the fire through the fire retardant panel door 10, 210, and 410 and door frames 30 and 230, respectively.

The fire retardant panel doors 10, 210, and 410 and the door frames 30 and 230, respectively, of this invention have undergone special testing by I.T.S. Warnock Hersey Laboratory for fire resistance and have passed the fire burn test known as ANSI/U.L. 10B1978 including the hose stream test. By passing this fire burn test, the doors 10, 210, and 410 and the door frames 30 and 230, respectively, can be specified by architects for many building uses where metal doors and wood flush doors would have been previously used.

The I.T.S. test under ANSI/U.L. 10B1978 includes the following steps:

1. The door structure to be tested is placed within a brick retaining wall.

2. One side of the door is subjected to an intense fire on a time temperature curve from 0 to 90 minutes and room temperature to 1,462° F. temperature. More specifically, the time-temperature is as follows:

Start: Room temperature
5 minutes: 1000° F.
10 minutes: 1300° F.
20 minutes: 1462° F.
30 minutes: 1550° F.
40 minutes: 1620° F.
50 minutes: 1650° F.
60 minutes: 1700° F.
70 minutes: 1750° F.
80 minutes: 1785° F.
90 minutes: 1785° F.

3. Immediately after the 90 minute burn period, the burned side of the door is subjected to a hose stream test from: a) a 2½ inch water supply hose; b) discharged through a tapered nozzle with a one (1) inch outlet opening; c) regulated to a 30 PSI discharge pressure; d) applied a distance of 20 feet from the door structure; and e) the time period of application of the water stream against the middle and all exposed parts of the door structure is controlled at a rate of 1.5 seconds per square foot.

The door being tested passes this testing procedure if no door panel or door members are disengaged from the supporting door frame assembly and if no openings are created.

In summary, the fire retardant panel doors 10, 210, and 410 and the door frames 30 and 230, respectively, of the present invention have passed a ninety (90) minute burn test performed by a I.T.S. testing laboratory to obtain and meet the fire resistant specification known as the ANSI/U.L. 10B fire burn test for doors.

ADVANTAGES OF THE PRESENT INVENTION

Accordingly, it is an advantage of the present invention that it provides a reinforced fire retardant panel door and door frame that prevents buckling of the door during a fire.

Another advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that has supplemental fire resistant materials strategically embedded and placed within the tongue and groove joints of the fire resistant panel door, as well as supplemental fire resistant materials placed on the perimeter edges of the fire resistant panel door for preventing the spread of fire through the door and door frame

Another advantage of the present invention is that is provides for a reinforced fire retardant panel door and door frame that has intumescent and fire resistant material layers within the panel door and door frame for preventing the spread of fire through the door and door frame.

Another advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that has fire resistant materials being multiple layers of intumescent material that expands in the presence of fire such that the intumescent material closes and seals the component tongue and groove joints, as well as the perimeter edges of the fire retardant panel door for preventing the spread of fire through the door and door frame.

Another advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that is used as part of an interior or exterior personal living space, or workspace being installed within home dwellings, commercial buildings or industrial plants.

Another advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that has stiles and rails having metal L-shaped beads therein in order to form an exoskeleton for further strengthening and tying together the stiles and rails within the panel door in order to keep the panel door from buckling during a fire.

Another advantage of the present invention is that it provides for a reinforced panel door and door frame that has improved aesthetic qualities by having a maxium panel core thickness of ⅜ of an inch allowing for a minimum thickness of 1¾ inches of the fire resistant and reinforced panel door which allows for greater profiling (depth) of the exterior wood molding between the center panel and the stiles and rails.

Another advantage of the present invention is that it provides for a reinforced panel door and door frame that includes a heat activated door pin or door hook assembly for preventing the active (free) panel door from buckling during a fire.

Another advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that is aesthetically pleasing having the appearance of natural wood, and has achieved a successful fire rating of at least 90 minutes and passes a positive pressure test, and is easily installed in a building.

A further advantage of the present invention is that it provides for a reinforced fire retardant panel door and door frame that can be mass produced in an automated and economical matter and is readily affordable to the builder or consumer.

A latitude of modification, change, and substitution is intended in the foregoing disclosure, and in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

Claims

1. A fire retardant panel door, comprising:

a) a panel door having at least one door panel and stiles and rails;

b) said door panel including an interior composite section formed by a first plurality of layers of intumescent materials and a first plurality of layers of fire resistant materials disposed between and laminated to a pair of outer sections formed of wood for enclosing said interior composite section to form a composite laminated door panel;

c) each of said stiles including a first core formed of wood enclosed by a second plurality of layers of intumescent materials and a second plurality of layers of fire resistant materials; said second layers of intumescent and fire resistant materials enclosed by a first layer formed of wood to form a composite laminated stile;

d) each of said rails including a second core formed of wood enclosed by a third plurality of layers of intumescent materials and a third plurality of layers of fire resistant materials; said third layers of intumescent and fire resistant materials enclosed by a second layer formed of wood to form a composite laminated rail;

e) said first, second, and third plurality of layers of intumescent materials being activated to expand upon exposure to heat and/or fire to prevent the heat and/or fire from passing through said at least one door panel, said stiles and said rails of said panel door during a fire for at least 90 minutes; and

f) said at least one door panel being connected to said panel door by joints; and said joints having a fourth plurality of layers of intumescent materials and a fourth plurality of layers of fire resistant materials; wherein said fourth plurality of layers of intumescent materials in said joints being activated to expand upon exposure to heat and/or fire to seal said joints in order to prevent the heat and/or fire from passing through said panel door during a fire for at least 90 minutes.

2. A fire retardant panel door in accordance with claim 1, wherein said first plurality of layers of intumescent materials includes four intumescent layers and said first plurality of layers of fire resistant materials includes two fire resistant barrier layers for forming said interior composite section of said at least one door panel.

3. A fire retardant panel door in accordance with claim 2, wherein at least one of said four intumescent layers includes sodium silicate; and wherein at least one of said two fire resistant barrier layers includes a fire resistant metallo alumino silicate resin of said interior composite section.

4. A fire retardant panel door in accordance with claim 1, wherein said second plurality of layers of intumescent materials includes at least two intumescent layers and said second plurality of layers of fire resistant materials includes two fire resistant barrier layers for forming a first composite of said two intumescent layers and said two fire resistant barrier layers within said composite laminated stile.

5. A fire retardant panel door in accordance with claim 4, wherein at least one of said at least two intumescent layers includes sodium silicate and wherein at least one of said at least two intumescent layers includes rockwool silicates; and wherein at least one of said two fire resistant barrier layers includes a fire resistant metallo alumino silicate resin of said composite laminated stile.

6. A fire retardant panel door in accordance with claim 1, wherein said third plurality of layers of intumescent materials includes at least two intumescent layers and said third plurality of layers of fire resistant materials includes two fire resistant barrier layers for forming a second composite of said two intumescent layers and said two fire resistant barrier layers within said composite laminated rail.

7. A fire retardant panel door in accordance with claim 6, wherein at least one of said at least two intumescent layers includes sodium silicate and wherein at least one of said at least two intumescent layers include rockwool silicates; and wherein at least one of said two fire resistant barrier layers includes a fire resistant metallo alumino silicate resin of said composite laminated rail.

8. A fire retardant panel door in accordance with claim 1, wherein said fourth plurality of layers of intumescent materials includes four intumescent layers and wherein said fourth plurality of layers of fire resistant materials includes two fire resistant barrier layers for forming a third composite of said four intumescent layers and said two fire resistant barrier layers within a tongue section of said joints of said door panel.

9. A fire retardant panel door in accordance with claim 8, wherein at least one of said four intumescent layers includes sodium silicate; and wherein at least one of said two fire resistant barrier layers includes a fire resistant metallo alumino silicate resin of said tongue section.

10. A fire retardant panel door in accordance with claim 1, wherein at least one layer of each of said first, second, third, and fourth plurality of layers of intumescent materials is made from a sodium silicate; wherein at least one layer of each of said second and third plurality of layers of intumescent materials is made from rockwool silicates; and wherein at least one layer of each of said first, second, third and fourth plurality of layers of fire resistant materials is made from a fire resistant metallo alumino silicate resin.

11. A fire retardant panel door in accordance with claim 1, wherein said wood of said pair of outer sections is selected from the group consisting of oak, maple, walnut, poplar, and pine.

12. A fire retardant panel door in accordance with claim 1, wherein said first plurality of layers of intumescent materials, said first plurality of layers of fire resistant materials, and said pair of outer sections of wood are laminated together using adhesive and pressure to form said composite laminated door panel.

13. A fire retardant panel door in accordance with claim 1, wherein said first wood core of said stile is a yellow poplar microllem wood material.

14. A fire retardant panel door in accordance with claim 1, wherein said first wood layer of said stile is selected from the group consisting of oak, maple, walnut, poplar and pine.

15. A fire retardant panel door in accordance with claim 13, wherein said first wood core, said second plurality of layers of intumescent materials, said second plurality of layers of fire resistant materials and said first wood layer are laminated together using adhesive and pressure to form said composite laminated stile.

16. A fire retardant panel door in accordance with claim 1, wherein said second wood core of said rail is a yellow poplar microllem wood material.

17. A fire retardant panel door in accordance with claim 1, wherein said second wood layer of said rail is selected from the group consisting of oak, maple, walnut, poplar and pine.

18. A fire retardant panel door in accordance with claim 17, wherein said second wood core, said third plurality of layers of intumescent materials, said third plurality of layers of fire resistant materials and said second wood layer are laminated together using adhesive and pressure to form said composite laminated rail.

19. A fire retardant panel door in accordance with claim 1, wherein said joints are tongue and groove joints.

20. A fire retardant panel door in accordance with claim 19, wherein said tongue and groove joints each include a tongue section and a groove section.

21. A fire retardant panel door in accordance with claim 20, wherein each of said tongue sections and groove sections are held together by attachment means.

22. A fire retardant panel door in accordance with claim 21, wherein said attachment means includes a staple and/or a nail through said tongue section and a groove section of said tongue and groove joints.

23. A fire retardant panel door in accordance with claim 1, wherein said panel door includes perimeter edging having said third and fourth plurality of layers of intumescent materials therein which expand upon exposure to heat and/or fire to seal said perimeter edging relative to a door frame in order to prevent the heat and/or fire from passing through said panel door and said door frame during a fire.

24. A fire retardant panel door in accordance with claim 1, wherein said at least one door panel includes one or more mullions for separating two or more door panels of said panel door.

25. A fire retardant panel door in accordance with claim 24, wherein each of said mullions includes a third core formed of wood enclosed by a fifth plurality of layers of intumescent materials; a fifth plurality of layers of fire resistant materials; said fifth layers of intumescent materials and said fifth layers of fire resistant materials being enclosed by a third layer formed of wood to form a composite laminated mullion.

26. A fire retardant panel door in accordance with claim 24, wherein said fifth plurality of layers of intumescent materials includes at least two intumescent layers and wherein said fifth plurality of layers of fire resistant materials includes two fire resistant barrier layers for forming a fourth composite of said two intumescent layers and said two fire resistant barrier layers within said composite laminated mullion.

27. A fire retardant panel door in accordance with claim 26, wherein at least one of said at least two intumescent layers includes sodium silicate and wherein at least one of said at least two intumescent layers include rockwool silicates; and wherein at least one of said two fire resistant barrier layers includes a fire resistant metallo alumino silicate resin of said composite laminated mullion.

28. A fire retardant panel door in accordance with claim 24, wherein said third wood core of said mullion is a yellow poplar microllom wood material.

29. A fire retardant panel door in accordance with claim 24, wherein said third wood layer of said mullion is selected from the group consisting of oak, maple, walnut, poplar and pine.

30. A fire retardant panel door in accordance with claim 24, wherein said third wood core, said fifth plurality of layers of intumescent materials, said fifth plurality of layers of fire resistant materials and said third wood layer are laminated together using adhesive and pressure to form said composite laminated mullion.

31. A fire retardant panel door in accordance with claim 23, wherein said door frame includes jambs and an upper header.

32. A fire retardant panel door in accordance with claim 31, wherein each of said jambs includes a fourth core formed of wood enclosed by a sixth plurality of layers of intumescent materials and a sixth plurality of layers of fire resistant materials; said sixth layers of intumescent materials and said sixth plurality of layers of fire resistant materials are enclosed by a fourth layer formed of wood to form a composite laminated jamb.

33. A fire retardant panel door in accordance with claim 32, wherein said sixth plurality of layers of intumescent materials includes at least one intumescent layer and wherein said sixth plurality of layers of fire resistant material includes one fire resistant barrier layer for forming a fifth composite of said one intumescent layer and said one fire resistant barrier layer within said composite laminated jamb.

34. A fire retardant panel door in accordance with claim 33, wherein at least one of said intumescent layers includes sodium silicate; wherein at least one of said intumescent layers include rockwool silicates; and wherein said fire resistant barrier layer includes a fire resistant metallo alumino silicate resin.

35. A fire retardant panel door in accordance with claim 32, wherein said fourth wood core of said jamb is selected from the group consisting of oak, maple, walnut, poplar and pine.

36. A fire retardant panel door in accordance with claim 32, wherein said fourth wood layer of said jamb is selected from the group consisting of oak, maple, walnut, poplar and pine.

37. A fire retardant panel door in accordance with claim 32, wherein said fourth wood core, said sixth plurality of layers of intumescent materials, said sixth plurality of layers of fire resistant materials and said fourth wood layer are laminated together using adhesive and pressure to form said composite laminated jamb.

38. A fire retardant panel door in accordance with claim 31, wherein said upper header includes a fifth core formed of wood enclosed by a seventh plurality of layers of intumescent materials and a seventh plurality of layers of fire resistant materials; said seventh layers of intumescent materials and said seventh plurality of layers of fire resistant materials are enclosed by a fifth layer formed of wood to form a composite laminated upper header on said door frame.

39. A fire retardant panel door in accordance with claim 38, wherein said seventh plurality of layers of intumescent materials includes two intumescent layers and wherein said seventh plurality of layers of fire resistant materials includes at least one layer of fire resistant barrier layer for forming a sixth composite of said two intumescent layers and said one fire resistant barrier layer within said composite laminated upper header.

40. A fire retardant panel door in accordance with claim 39, wherein at least one of said two intumescent layers includes sodium silicate; and wherein at least one of said two intumescent layers includes rockwool silicates; and wherein at least one of said fire resistant barrier layers includes a fire resistant metallo alumino silicate resin.

41. A fire retardant panel door in accordance with claim 38, wherein said fifth wood core of said upper header is selected from the group consisting of oak, maple, walnut, poplar and pine.

42. A fire retardant panel door in accordance with claim 38, wherein said fifth wood layer of said upper header is selected from the group consisting of oak, maple, walnut, poplar and pine.

43. A fire retardant panel door in accordance with claim 38, wherein said fifth wood core, said seventh plurality of layers of intumescent materials, said seventh plurality of layers of fire resistant materials and said fifth wood applique layer are laminated together using adhesive and pressure to form said composite laminated upper header.

44. A fire retardant panel door in accordance with claim 38, wherein said door frame includes perimeter surface walls having said sixth and seventh plurality of layers of intumescent materials therein which expand upon exposure to heat and/or fire to seal said perimeter surface walls within said door frame in order to prevent the heat and/or fire from passing through said panel door and said door frame during a fire.

45. A fire retardant panel door in accordance with claim 1, further including a double door assembly having a first panel door with one or more door panels, stiles, and rails, and having a second panel door with one or more door panels, stiles, rails, and mullions within a double door frame.

46. A fire retardant panel door in accordance with claim 19, wherein said tongue and groove joints include first air gaps between said first plurality of layers of intumescent materials of said door panel and said second plurality of layers of intumescent materials of said stile for expansion of said first and second plurality of layers of intumescent materials within said first air gaps upon exposure to heat and/or fire to seal said tongue and groove joints in order to prevent the heat and/or fire from passing through said door panel and said stile during a fire.

47. A fire retardant panel door in accordance with claim 19, wherein said tongue and groove joints include second air gaps between said first plurality of layers of intumescent materials of said door panel and said third plurality of layers of intumescent materials of said rail for expansion of said first and third plurality of layers of intumescent materials within said second air gaps upon exposure to heat and/or fire to seal said tongue and groove joints in order to prevent the heat and/or fire from passing through said door panel and said rail during a fire.

48. A fire retardant panel door in accordance with claim 19, wherein said tongue and groove joints include third air gaps between said second plurality of layers of intumescent materials of said stile and said third plurality of layers of intumescent materials of said rail for expansion of said second and third plurality of layers of intumescent materials within said third air gaps upon exposure to heat and/or fire to seal said tongue and groove joints in order to prevent the heat and/or fire from passing through said stile and said rail during a fire.

49. A fire retardant panel door in accordance with claim 1, wherein said first plurality of layers of intumescent materials includes five intumescent layers and wherein said first plurality of layers of fire resistant materials includes at least one fire resistant barrier layer for forming said interior composite section.

50. A fire retardant panel door in accordance with claim 1, wherein said composite laminated style further includes a plurality of metal L-shaped beads being positioned between one of said second plurality of layers of intumescent materials and one of said second plurality of layers of fire resistant materials in conjunction with said intumescent and fire resistant material layers together to form an exoskeleton layer in order to further strengthen said composite laminated stile.

51. A fire retardant panel door in accordance with claim 1, wherein said composite laminated rail further includes a plurality of metal L-shaped beads being positioned between one of said third plurality of layers of intumescent materials and one of said third plurality of layers of fire resistant materials in conjunction with said intumescent and fire resistant material layers together to form an exoskeleton layer in order to further strengthen said composite laminated rail.

52. A fire retardant panel door in accordance with claim 32, wherein said composite laminated jamb further includes a pair of metal L-shaped beads being positioned between one of said sixth plurality of intumescent materials and one of said sixth plurality of layers of fire resistant materials in conjunction with said intumescent and fire resistant material layers together to form a partial exoskeleton layer in order to further strengthen said composite laminated jamb.

53. A fire retardant panel door in accordance with claim 1, wherein one of said composite laminated stiles includes an upper corner having a heat activated door pin assembly therein.

54. A fire retardant panel door in accordance with claim 53, wherein said heat activated door pin assembly includes a housing member and a hollow door bolt pin having an internal compressive spring and a rod member therein.

55. A fire retardant panel door in accordance with claim 54, wherein said door bolt pin being movable from an unexpanded first position to an expanded second position.

56. A fire retardant panel door in accordance with claim 55, wherein said compressible spring and said rod member together include an upper rod end having a fusible solder link therein which melts at least at 117° F. allowing said combined compressible spring and fusible solder link to eject said door bolt pin through a strike plate opening of a strike plate located within a bolt opening of said upper header to said expanded second position in order to prevent any movement of said upper corner of said stile of said fire retardant panel door relative to said door frame.

57. A fire retardant panel door in accordance with claim 54, wherein said housing member includes a pin opening for receiving said door bolt pin therein and having a proximal end and a distal end.

58. A fire retardant panel door in accordance with claim 57, wherein said proximal end of said housing member of said heat activated door pin assembly includes a pair of intumescent pads which upon exposure to excessive heat and/or fire expands rapidly to at least 22 times its original thickness in order to permanently lock said door bolt pin in said expanded second position within said upper-bolt opening of said upper header of said door frame.

59. A fire retardant panel door in accordance with claim 1, wherein on of said composite laminated stiles includes an upper corner having a heat activated door hook assembly therein.

60. A fire retardant panel door in accordance with claim 59, wherein said heat activated door hook assembly includes a housing member having an internal compressible spring having a first spring end and a second spring end attached to a hook member having a hook section fusible solder link therein.

61. A fire retardant panel door in accordance with claim 60, wherein said compressible spring and hook member being movable from a tensioned first position to an untensioned second position.

62. A fire retardant panel door in accordance with claim 61, wherein said first spring end of said compressible spring is detachably connected to a first end of said fusible solder link and said second spring end of said compressible spring is attached to a second end of said fusible solder link which melts at least at 117° F. allowing said combined compressible spring and hook member to rotatably move in a clockwise motion such that said hook section of said hook member moves through a strike plate opening of an upper strike plate located within an opening of said upper header to said untensioned second position in order to prevent any movement and buckling of said upper corner of said stile of said fire retardant panel door relative to said door frame when exposed to heat and/or fire.

63. A fire retardant panel door, comprising:

a) a panel door having a door panel;

b) said door panel including an interior composite section formed of a first plurality of layers of intumescent materials and a first plurality of layers of fire resistant materials disposed between and laminated to a pair of outer sections formed of wood for enclosing said interior composite section to form a composite laminated door panel; and

c) said first plurality of layers of intumescent materials being activated to expand upon exposure to heat and/or fire to prevent the heat and/or fire from passing through said door panel of said panel door and a door frame during a fire.

64. A fire retardant panel door in accordance with claim 63, wherein said first plurality of layers of intumescent materials includes at least five intumescent layers for forming said interior composite section, wherein at least one of said at least five intumescent layers includes sodium silicate and wherein at least one of said at least five intumescent layers include rockwool silicates; and wherein at least one of said fire resistant layers includes a fire resistant metallo alumino silicate resin.

65. A heat activated door pin assembly for preventing the movement and buckling of an upper free corner of a panel doors comprising:

a) a housing member being substantially cylindrically-shaped having an opening and an interior compartment for receiving a hollow door bolt pin therein, said interior compartment having a proximal end and a distal end;

b) said hollow door bolt pin including an internal compressive spring and a rod member having a proximal rod end and a distal rod end therein;

c) said distal rod end of said rod member including a fusible solder link;

d) said fusible solder link melting at least at 117° F.; and

e) said door bolt pin being movable from an expanded first position to an expanded second position when activated by excessive heat and/or fire.

66. A heat activated door pin assembly in accordance with claim 65, wherein said compressible spring and said fusible solder link activates at 117° F. by excessive heat and/or fire allowing said compressible spring to eject said door bolt pin through a strike plate opening of a strike plate located within a bolt opening of said upper header to said expanded second position in order to prevent any movement and buckling of said upper free corner of said fire retardant panel door relative to said door frame.

67. A heat activated door pin assembly in accordance with claim 65, wherein said proximal end of said housing member of said that heat activated door pin assembly includes a pair of intumescent pads which upon exposure to excessive heat and/or fire expands rapidly to at least 22 times its original thickness in order to permanently lock said door bolt pin in said expanded second position within said upper-bolt opening of said upper header of said door frame.

68. A heat activated door hook assembly for preventing the movement and buckling of an upper free corner of a panel door, comprising:

a) a housing member being substantially rectangularly-shaped housing a top wall in the form of a strike plate, a bottom wall, a front wall, a rear wall and side walls for forming an interior compartment;

b) said interior compartment of said housing member including a movable door hook member having a hook section, a shaft opening, an end section, a front wall and a rear wall; a shaft member; an internal compressible spring having a first spring end and a second spring end; and a fusible solder link having a first solder link end and a second solder link end;

c) said strike plate including a hook opening for receiving said hook section of said movable door hook member and a solder link opening for receiving said first solder link end of said fusible solder link therethrough;

d) said compressible spring being attached to said front wall of said door hook member and adjacent to said shaft opening; said shaft opening of said door hook member pivots on said shaft member;

e) said first spring end of said compressible spring is received within a pin opening of said side wall in order to hold said compressible spring in place on said side wall;

f) said second solder link end is attached to said second spring end of said compressible spring, wherein said compressible spring is in an unexpanded configuration;

g) said fusible solder link melting at least 117° F.; and

h) said hook section of said door hook member and said compressible spring being rotatable in a clockwise motion from a tensioned first position to an untensioned second position when activated by excessive heat and/or fire.

69. A heat activated door hook assembly in accordance with claim 68, wherein said compressible spring and said fusible solder link is activated at said 117° F. by excessive heat and/or fire allowing said compressive spring to rotatably move said hook section of said door hook member through an upper strike plate located within an opening of an upper header to said untensioned second position in order to prevent any movement and buckling of said upper free corner of said panel door relative to a door frame when exposed to heat and/or fire.

70. A heat activated door hook assembly in accordance with claim 68, wherein said strike plate includes opposing ends each having a mounting opening therethrough for receiving a mounting screw therein.

71. A heat activated door hook assembly in accordance with claim 68, wherein said front and rear walls include shaft openings for receiving and attaching said shaft member therein.

72. A heat activated door hook assembly in accordance with claim 68, wherein said bottom wall includes a bottom opening for accessing said door hook member.

73. A heat activated door hook assembly in accordance with claim 71, wherein shaft opening of said door hook member pivots about said attached shaft member, where then said hook section of said door hook member rotatably moves within said upper strike opening of said upper strike plate permanently such that said hook section prevents any movement and buckling of said upper free corner of said panel to said untensioned second position when activated by excessive heat and/or fire.