Abstract: A sound attenuating partition or door construction which includes outside rigid panels having significantly different thicknesses, a void being left between the panels, a sheet characterized as a limp mass loosely hung within the void, and grooves cut into an inner surface of at least one of the outside panels in order that the void serves as a sound absorbing anechoic chamber.
Abstract: A composite wood material, specially adapted for use as part of a door with a long fire rating, comprising a board material made of wood chips and fire-retardant chemicals and one or more sheets of material of pressed wood fibers with a fire retardant added thereto, designed to optimize resistance to penetration by fire, increase screw holding ability, resist splitting and minimize cost.
Abstract: A solid board, specially adapted for use as a door with a long fire rating, comprising a fire resistant core material with edges thereon formed of a plurality of layers of sheet material of pressed wood fibers with a fire retardant added thereto. A fire door so constructed combines the advantages of a high fire rating and thick wooden edges for securely holding door mounting hardware.
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