Static structures (e.g. – buildings) – Irreversibly reactive component
Reexamination Certificate
1998-12-24
2001-02-06
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Irreversibly reactive component
C052S381000, C052S383000, C052S784110, C052S787110, C052S800120
Reexamination Certificate
active
06182407
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fire barrier wall which includes an intumescent material, and, in particular, to a two hour fire barrier wall which includes a single layer of gypsum board secured to each side of the studs within the wall and an intumescent material barrier, such as but not limited to: an intumescent coating layer containing expandable particulate graphite applied to the interior or exterior of one or both gypsum board layers; a fibrous insulation blanket, located intermediate the gypsum board layers, with an intumescent material (e.g. an intumescent coating) layer on one or both surfaces of the blanket; a woven or non-woven fibrous mat layer or layers coated with an intumescent coating containing expandable particulate graphite located on the exterior of or intermediate the gypsum board layers; or a woven or non-woven fibrous mat layer or layers with expandable particulate graphite dispersed throughout the mat located on the exterior of or intermediate the gypsum board layers or combinations thereof.
Gypsum board fire barrier walls
120
, having two hour performance ratings, are currently constructed, as shown in FIG.
6
. As currently constructed, these two hour fire barrier walls
120
include two layers
122
and
124
of vertically extending five-eights of an inch, type X, gypsum wallboard attached by screws to both sides of metal screw or wooden studs
126
that are spaced apart on sixteen or twenty four inch centers. The cavity defined by the interior surfaces of the inner gypsum boards and the studs is filled with an insulation material
128
, such as a glass fiber or mineral wool insulation blanket. While performing as required, the use of two layers of gypsum wallboard (each wallboard layer weighing approximately 2200 pounds/thousand square feet) on both sides of the studs in these fire barrier walls adds significantly to the weight to be supported by the structural framework of a building. In addition, the time and labor involved in handling and installing two layers of gypsum wallboard on each side of the studs can add to the construction costs. Thus, there has been a need for an inexpensive, easy to install, gypsum board fire barrier wall with a two hour performance rating that does not require the use of two layers of gypsum wallboard on both sides of the studs.
Intumescent materials, such as those disclosed in U.S. Pat. No. 3,574,644; issued Apr. 13, 1971; Franciszek Olstowski et al (hereinafter “the '644 patent), can be applied (as stated in column 3, lines 1-5 of the '644 patent) in the form of a coating to “normally combustible or heat degradable materials such as wood, fiber-board, plastics, insulative ceilings or wall panels, other cellulosic building materials, or the like” to increase the flame resistance of such normally combustible or heat degradable materials. These intumescent materials form passive fire protection systems which remain inactive until subjected to heat and temperatures such as those encountered from the flames of a fire. When these passive fire protection systems are subjected to heat and temperatures, such as those encountered in a fire, these intumescent materials react, grow and expand forming a char (many times the original thickness of the coating applied) to insulate the surface to which the material is applied from the damaging effects of the heat generated by the fire.
While these materials can be quite effective as fire barriers, these intumescent materials can be corrosive to steel, stainless steel, copper, aluminum and other metals or metal alloys, such as those commonly used in the construction industry. Thus, in applications, where these intumescent materials come in contact with metal components, e.g. metal fasteners such as screws or nails used to secure gypsum board to studs, the metal studs and other metal structural members or utilities such as piping and the like, the use of these intumescent materials can cause corrosion problems and although the disclosure of the '644 patent has been available to the construction industry for over twenty five years, gypsum board fire barrier walls are still constructed, as set forth above and shown in
FIG. 6
, using two layers of gypsum wallboard on both sides of the studs.
SUMMARY OF THE INVENTION
The gypsum board/intumescent material fire barrier wall of the present invention provides a solution to the need for a single layer gypsum board fire barrier wall. The gypsum board/intumescent material fire barrier wall of the present invention includes spaced apart, vertically extending metal or wooden studs with only one layer of gypsum board secured to each side of the metal or wooden studs to form a fire barrier wall with a series of wall cavities. The fire barrier wall also includes an intumescent material barrier that is at least coextensive in width and height with the wall cavities and preferably, a fibrous insulation material such as but not limited to a glass fiber or mineral wool insulation within the wall cavity. Preferably, the spaced apart gypsum board layers, with the intumescent material barrier, provide the fire barrier wall with two hour fire-resistive properties meeting or exceeding ASTM test standard E119 for walls and partitions.
In the first and second embodiments of the invention, the intumescent material barrier includes one or two intumescent coating layers, containing expandable particulate graphite, applied directly to the interior and/or exterior of one or both major surfaces of both of the gypsum boards. The coating layer or layers can be applied at the factory or at the job site. Preferably, the intumescent coating layers are coextensive in width and height with the major surfaces of gypsum boards to which the layers are applied so that the intumescent material layer overlays the outer sidewall surfaces of the metal or wooden studs to which the gypsum boards are affixed.
In a third embodiment of the present invention, the intumescent barrier includes one or two intumescent coating layers, containing expandable particulate graphite, applied directly to the one or two major surfaces of a fibrous insulation blanket, such as a glass fiber or mineral wool insulation blanket. The intumescent coating layer or layers on the major surfaces of the fibrous insulation blanket not only provide the intumescent material barrier required for the fire barrier wall, but the intumescent material layers may also enhance the product by stiffening the fibrous insulation blanket (batt) to make the blanket easier to handle and install and by encapsulating the fibers of the fibrous insulation blanket to reduce the exposure of fibers. The coating layer or layers can be applied at the factory or at the job site. The intumescent barrier formed by the coated fibrous insulation is coextensive in width and height with the cavity formed by the gypsum board layers and studs and may overlay the inner sidewall surfaces of the studs to which the gypsum board layers are affixed. Where the intumescent curtain or mat layers do not overlay the inner sidewall surfaces of the studs to which the gypsum board layers are affixed, the outer sidewall surfaces of the studs may be coated with an intumescent material layer.
In a fourth embodiment of the present invention, the intumescent material barrier may be a woven or non-woven fibrous mat layer or layers with an intumescent coating containing expandable particulate graphite or a woven or non-woven fibrous mat layer or layers with expandable particulate graphite dispersed throughout the mat. When applied as a coating, the coating layer or layers can be applied at the factory or at the job site. Such an intumescent material layer or layers can be sandwiched between fibrous insulation layers within the wall cavity; applied intermediate a fibrous insulation layer and the inner major surface of one or both gypsum boards; or applied to the exterior major surface of one or both gypsum boards. The intumescent material coated or containing mat layer(s) are coextensive in width and height with the c
Burdic Bradley
Larson Reed H.
Shumate Monroe W.
Turpin Kenneth A.
Versen Richard A.
Friedman Carl D.
Horton Yvonne M.
Johns Manville International Inc.
Lister John D.
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