Firedoor constructions including gypsum building product
AssigneeGeorgia-Pacific Corporation
InventorsTurner W. Richards, Hubert C. Francis, George F. Fowler
Life of this patent
Estimating the term…
Abstract
Firedoor constructions manufactured from board compositions containing calcium sulfate in hemi-hydrate or anhydrous form and fibrous additives, including pulped paper fibers preferably derived from waste newspaper, capable of being formed into firedoor members having superior mechanical properties and/or fire resistance.
Claims12
A solid fire door which has a core bounded by facings on each major surface and edge banding which includes vertical stiles and horizontal rails, the improvement in which the edge banding includes by weight about 68% to about 78% set gypsum derived from calcined nonfibrous gypsum, about 7% to about 30% pulped paper fiber, up to about 15% binder polymer, up to about 7% inorganic fiber, up to about 6% clay, and up to about 6% vermiculite, said edge banding having a density of at least about 70 lbs./cu. ft. and screw-holding capacity of at least about 700 lb., whereby the fire door attains a 1.5 hour fire endurance rating when tested according to ASTM E-152, said edge banding prepared, at least in part, by mixing said calcined nonfibrous gypsum with a quantity of water in excess of that required to completely hydrate the calcined nonfibrous gypsum to form said set gypsum.
A fire door having a partially hollow core bounded by facings on each major surface and edge banding which includes vertical stiles and horizontal rails, the improvement in which the facings comprise by weight about 75% to about 90% set gypsum derived from calcined nonfibrous gypsum, about 10% to about 14% pulped paper fiber, up to about 9% binder polymer, and about 0.8% to about 2% inorganic fiber, said facings having a density of at least about 60 lbs./cu. ft., whereby the door attains a 20 min. fire endurance rating when tested according to ASTM E-152, said facings prepared, at least in part, by mixing said calcined nonfibrous gypsum with a quantity of water in excess of that required to completely hydrate the calcined nonfibrous gypsum to form said set gypsum.
A firedoor comprising a fiberboard element having a screw-holding capacity of at least about 650 lbs. and including at least about 7 wt. % homogeneously distributed paper pulp and at least about 65 wt. % set gypsum dihydrate derived substantially from gypsum hemihydrate, said firedoor having a fire endurance rating of at least 20 minutes when tested in accordance with ASTM E-152.
Dependencies are inferred from the claim text.