Static structures (e.g. – buildings) – Ornamental: color – thickness variation – or dissimilar... – Visible discrete elements in cast material
Reexamination Certificate
1998-03-05
2001-06-05
Stephan, Beth A. (Department: 3635)
Static structures (e.g., buildings)
Ornamental: color, thickness variation, or dissimilar...
Visible discrete elements in cast material
C052S309800, C052S387000, C052S389000
Reexamination Certificate
active
06240691
ABSTRACT:
BACKGROUND
Some of the earlier prior art in this area includes U.S. Pat. Nos. 3,646,715 and 3,715,417 (Pope) assigned to Dupont of Canada and U.S. Pat. No. 3,740,909 (Stinnes) to the same Assignee.
This invention relates to a prefabricated composite building panel of the type comprising a rigid foam sheet of foamed cellular polymeric material, such as polyurethane or the like, on an outer face of which is attached a plurality of facing elements, such as brick slices, which are partially embedded in and attached to the outer face by the foaming action of the polymeric material. The facing elements are arranged in a pattern with spaces between the facing elements with those spaces being filled by a covering layer on the outer face of the foam sheet which is preferably formed of an aggregate intimately bonded into or integrated with the outer face of the foam sheet by the foaming action of the polymeric material. The basic model of this type of building panel is best outlined in our issued U.S. Pat. No. 5,715,637 to Hesterman et al.
All of these patents relate to a system of manufacturing prefabricated composite panels which has achieved some commercial success. One point which has to some extent limited commercial success is that of a restriction in the fire retardant qualities of the product. The brick facing elements are of course resistant to combustion. The aggregate which is embedded into the outer layer of the polyurethane foam sheet is also resistant to combustion. However the polyurethane foam itself is combustible and hence there is some possibility of the panel as a whole reaching a state of combustion so that the panel breaks down allowing direct access by the flame to the foam which can then bum freely eventually allowing access to the wall structure behind the panel.
Combustion tests have been observed and it has been found that once the aggregate layer filling the spaces between the facing elements has been breached by the combustion, rapid combustion of the polyurethane foam behind the facing elements and the aggregate soon occurs thus causing breakdown of the panel. Thus the panel is resistant to combustion for an initial period of time but once the layer is breached then the breakdown of the panel soon follows.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a prefabricated composite building panel with greater fire-retardant capabilities than those such panels currently available, and which will allow prefabricated building panels of this type to meet stringent fire safety standards.
It is the further object of the present invention to provide a prefabricated composite building panel with a fireproof barrier, wherein the fire barrier is cementitious in nature.
The invention, a prefabricated composite building panel with a fire barrier, accomplishes its objects comprising substantially a prefabricated composite building panel for attachment to a vertical wall of a building comprising a rigid sheet of cellular polymeric material having an outer face for facing outwardly of the wall and an inner face for facing inwardly of the wall; a set layer of a cementitious material, said cementitious layer being separate from the sheet and being bonded to the outwardly facing face of the sheet; a plurality of rigid facing elements carried on the outer face of the cementitious layer so as to define an outermost surface of the panel, the facing elements being carried in a pattern defining spaces between at least some of the facing elements and adjacent ones of the facing elements; and a plurality of support strips engaging the cementitious layer, the polymeric sheet and the facing elements.
The support strips which have been added are made of metal, and engage and provide support for the facing elements and the cementitious layer.
It has been found that the vertical stability of the panel and the facing elements can be further improved by strengthening the cementitious layer. Fibreglass strands or other conventional strengthening methods might be used.
Yet further an improvement can be obtained by adding gypsum or another fire retardant material to the cementitious material as an intimately mixed composite. The gypsum carries water molecules which, when heated, give off the water as water vapour providing a significant cooling action on the product. This addition of gypsum would assist in maintaining the cementitic us layer in a cooled condition to yet further prevent or inhibit the penetration of the combustion through the cementitious layer to the underlying polyurethane foam sheet.
The strength and thickness of the cementitious layer should be sufficient to provide support for the facing elements in a fire situation. The cementitious layer should fill the spaces between the facing elements to a partial depth, to provide support to the facing elements and yield a conventional brickwork pattern. The cementitious layer also covers a rear surface of the facing elements so as to define a layer portion between the elements and the front face of the sheet. The cementitious layer should be rigid.
The support strips might have many configurations. In one embodiment, the support strip includes an upper hanger portion having a generally horizontal element for engaging a part of the polymeric sheet and a part of the cementitious layer for communicating downward forces from the facing elements into the sheet.
Where the support strip includes a substantially vertical strip, proper support to the facing elements in a fire will be provided. The support strips might also include a plurality of vertical elongate members Lt spaced positions horizontally of the panel. Where the facing elements comprise rectangular bodies arranged in rows with spaces therebetween, the support strips are arranged to engage a plurality of the facing elements.
The support strips could be made of metal, or other materials which would provide the same degree of support as metal in the event of a fire, and can be molded into the cementitious layer and the polymeric sheet.
A support panel can also be added to the back of the polymeric sheet, the support panel being plywood or some other material. The support panel is bonded into place on the rear surface of the sheet via the foaming action of the sheet.
An interlocking effect can be achieved by arranging the rectangular facing elements in rows with spaces therebetween, the pattern being arranged such that at each end of the panel there are a plurality of the facing elements some of which have a portion thereof projecting from and exposed at the end of the sheet, each of said elements having a portion of the sheet behind the element, and support strips embedded within the sheet and/or the layer and extending into the portion of the sheet and/or the layer behind the element. In panels with a support panel, this effect can be accomplished by leaving the projecting elements exposed beyond both ends and the bottom of the sheet.
The panel of the present invention could be manufactured by providing a horizontal, generally planar mold having a plurality of receptacles each for receiving a respective one of a plurality of rigid facing; elements so as to arrange the elements with front faces thereof in a common horizontal plane in a pattern defining spaces between side edges of at least some of the facing elements and side edges of adjacent ones of the facing elements; placing an element in each of the receptacles; applying into the mold a layer of a cementitious material so as to fill in at least a portion of the spaces between the facing elements and thinly cover the rear face of the facing elements and to engage the portions of the support strips which are in contact with the cementitious material, the cementitious material having setting characteristics so as to set to a rigid condition to form a substantially rigid surface exposed in the mold; placing support strips into the mold before the cementitious material sets to its rigid condition; applying a support panel over the mold so as to leave a space between the exposed surface and the suppo
Hesterman Larry
Holzkaemper Rolf
Frost Brown Todd LLC
Pan-Brick Inc.
Stephan Beth A.
LandOfFree
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