Multi-layered fire door and method for making the same
A door has a core that includes a porous layer having a thickness and two opposing major surfaces. In one construction, the core also includes three fire-retardant layers, and two of the fire-retardant layers are separated by the porous layer. The porous layer and the fire-retardant layers are coupled together. Other constructions include one or more fire-retardant layers in balanced or unbalanced placement around the porous layer.
1 - 18 . (canceled)
19 . A method of making a door comprising:
providing a core comprising a porous layer having two opposing major surfaces and at least three fire-retardant layers each comprising a fiberboard; and
coupling together the porous layer and the at least three fire-retardant layers in an unbalanced construction, wherein a number of the at least three fire-retardant layers disposed on one of the two opposing major surfaces of the porous layer is greater than a number of the at least three fire-retardant layers disposed on another one of the two opposing major surfaces of the porous layer.
20 - 21 . (canceled)
22 . The method of making the door according to claim 19 , further comprising:
coupling a first exterior layer to one surface of the core; and
coupling a second exterior layer to another surface of the core, wherein a door blank is formed.
23 . The method of making the door according to claim 22 , further comprising applying a uniform pressure to the door blank for a period of time.
24 . The method of making the door according to claim 23 , wherein the uniform pressure is in a range between about 80 and about 110 pounds per square inch and the period of time is about 30 minutes.
25 - 40 . (canceled)
41 . The method of making the door according to claim 22 , further comprising machining a grooved first pattern having a first depth on the first exterior layer.
42 . The method of making the door according to claim 41 , wherein the first depth penetrates a thickness of the first exterior layer and a portion of a thickness of one of the at least three fire retardant layers.
43 . The method of making the door according to claim 42 , further comprising machining a grooved second pattern having a second depth on the second exterior layer, wherein the second depth penetrates a thickness of the second exterior layer and a portion of a thickness of another one of the at least three fire retardant layers.
44 . The method of making the door according to claim 43 , wherein the first and second depths are about the same.
45 . The method of making the door according to claim 19 , wherein a density of the porous layer is at least one pound per cubic foot.
46 . The method of making the door according to claim 19 , wherein the porous layer comprises a thermoplastic polymer.
47 . The method of making the door according to claim 19 , wherein the porous layer comprises a fire-retardant material.
48 . The method of making the door according to claim 19 , wherein a thickness of each of the at least three fire-retardant layers is about the same.
49 . The method of making the door according to claim 48 , wherein a thickness of the porous layer is about the same as the thickness of each of the at least three fire-retardant layers.
50 . The method of making the door according to claim 19 , wherein the fiberboard comprises a medium-density fiberboard comprising a density of at least 42 pounds per cubic foot.