Patent ID: 7669383
Filing Date: 2010-03-02
Classification: E06B

Abstract:
1. A fire door, comprising: a substantially rectangular core, top and bottom rails each formed substantially of a mineral based, fire resistant material, and a pair of stiles connected to the core along opposing side edges of the door, an axis being defined through the core, perpendicular to the side edges, and parallel to the rails, each including a series of material layers stacked along the axis in a direction from the core toward a respective side edge in the following order: (a) a first layer of fire resistant particle board; (b) an intumescent layer adjacent to the first layer of fire resistant particle board; (c) a second layer of fire resistant particle board adjacent to the layer of intumescent material, and (d) a layer of wood having sufficient thickness and density to achieve a fire door rating of at least 45 minutes.