US3217456A - Structural member with multi-layered gypsum board fire protection - Google Patents

Description

NOV. 16, 1965 P. s. QUIGG ETAL STRUCTURAL MEMBER WITH MUTI-LAYERED GYPSUM BOARD FIRE PROTECTION Filed Oct. l2, 1962 l Ew pla S. Qur-yg ,Nels /Velgsmy United States Patent C) 3,217,456 STRUCTURAL MEMBER WITH MULTl-LAYERED GYPSUM BOARD FIRE PROTECTION Paul S. Quigg, Barrington, and Nels Nelsson, Des Plaines,

Ill., assignors to United States Gypsum Company,

Chicago, Ill., a corporation of Illinois Filed Oct. 12, 1962,Ser. No. 230,059 1 Claim. (Cl. 52-423) This invention pertains to tire resistant building constructions and more particularly to gypsum board coverings for retarding the effects of fire upon structural elements.

One important criterion in building constructions is the ability of the structure to withstand the effects of lire. Acceptable structures must be capable of retaining their structural integrity for a substantial period of time even through subjected to an internal or external conflagration. This quality of a structure and/ or its components to withstand re conditions is commonly known as its lire rating and is measured in increments of time signifying the period for which the construction will maintain prescribed parameters, such as temperature, strength, or non-combustion of the components, under specified test conditions. One accepted standard for lire endurance ratings of the type of element to which this invention pertains is Underwriters Laboratories, Inc. testStandard for Fire Tests of Building Construction and Materials UL 263 (NFA 251, ATSM E 119). Fire ratings discussed hereinafter will be with reference to such a standard, except as may otherwise be noted.

An extremely important aspect of providing a satisfactory fire enduring building construction is the protection of the main frame members and particularly the support columns. The present invention will be disclosed and described herein with reference to this use and more particularly with reference to the fire protection of steel columns such as are used in many commercial type buildings.

When utilizing steel structural members it is normally necessary to protect them with coverings of suitable materials, such as gypsum panels, plaster, Portland cement concrete, or the like, to meet building code fire ratings which are usually prescribed by local authorities. Such codes normally require a minimum rating of two hours according to a standard fire endurance test such as that noted above. This however is merely a minimum rating required for approval of the construction. Notwithstanding the fairly common acceptance of a two hour rated construction by local authorities, an important reason for obtaining even higher re ratings has arisen from the present and increasing demand by insurance underwriters that structural members be sufliciently protected to achieve a minimum fire rating of three hours as added protection against re losses.

Along with the requirements for high re ratings, there remains the ever present necessity for economy of time and materials in building constructions. Consequently it is highly desirable that high iire ratings be obtained with constructions which may be easily and simply formed without the provision of special equipment and/or materials or the application of special skills.

The present invention provides an advantageous approach to the aforenoted problems by obtaining a high fire rating with components which are commonly utilized in so-called drywall interior constructions and are thus readily available. This, in turn facilitates erection and completion of a building as all interior constructions, including fire protection members, may be fabricated of the drywall components.

3,217,456 Patented Nov. 16, 1965 we ICC It is an object of this invention to provide an improved fire enduring covering of gypsum board panels for structural members, utilizing a minimum number of layers of panels to achieve maximum lire endurance ratings.

It is another object of this invention to provide improved fire enduring coverings for structuralfmembers which obtain high fire ratings and which may be conveniently and economically included in a building construction.

Further and additional objects and advantages will appear from the following description, accompanying drawings and appended claims.

In carrying out this invention in one illustrative form, a structural member is encased in superimposed layers of gypsum board panels, the panels of each layer forming joints Where the -edges of the panels meet, with an incombustile cover member secured over each of these joints. Adhesive material such as joint compound bonds each overlying layer of panels to the ysubjacent panels, -and wire binding members extend around each layer of panels and the respective cover members, except the outermost layer. Additional joint compound `is applied to -and V1inishes the exterior surface of the outer layer of panels.

For a more complete understanding of this invention, reference should now be had to the example illustrated in the accompanying drawings wherein:

FIG. l is a perspective View of a structural member with a re protective covering employing theteachings of this invention, the encasing covering being partially broken away;

FIG. 2 is a horizontal cross-sectional View of the construction in FIG. l;

FIG. 3 is a partial cross-sectional View taken along lines 3 3 of FIG. 2 and looking in the direction of the arrows;

FIG. 4 is an enlarged perspective view of a portion of one of the joint cover members utilized in the construction of FIG. 1, and

FIG. 5 is a partial cross-sectional view similar to FIG. 2 but illustrating an alternate surface treatment.

Referring now to the drawings, and more particularly to FIGS. l, 2 and 3, a fire protective construction 18 is disclosed as applied to and enclosing a steel I-beam column 20 comprising a web 21 and anges 22.

The column-encasing lire protective construction 18 includes a first layer of gypsum board panels 24 arranged around and enclosing the member 20 over its full exposed length. When the structural member 20 is of a rectangular peripheral conguration as illustrated, the `panels24 lmay be of a width greater than the corresponding sides of the structural member by an amount equal to the. panel thickness, whereby the panels fit snugly against the member and form neat, closed, overlap joints at each corner. Cover members 26a of an incombustible material are then placed over each of the corners and cover the joints between the panels 24.

The angle members 26, illustrated in FIG. 4 l(26a, 'b and c in the remaining figures) each comprise a metal angle having a pair of angularly disposed flanges 28 joined by a bulbous arcuate ridge or bead 29 which projects outward of the planes defined by flanges 28. The bead 29 facilitates placement of the flanges against the panel edges regardless of such slight irregularities as may occur at the corners of the panels 24 and-may serve as aground for applying other materials such as joint compound. Holes may be formed in the flanges as at 28a whereby lplastic joint compound placed over the lmembers 26 will pass through the holes, bond to the edgesof subjacent panels and key the resulting structure together.

When two or more artisens cooperate in applying the components of this construction to a structural member, the angle members 26a need not be secured to the edges of the panels since the artisans can cooperate and maintain them in place until subsequent holding structure is applied. However, when a single artisan applies the components, it is convenient to tack or nail these angles to the panels for temporary holding purposes.

Flexible binding members 30 are next placed around the first layer of panels 24 and the cooperating angles 26a at spaced intervals over the length of member 20. The binding members, which are of incombustible materials and preferably comprise steel wires, are drawn snug and tied or otherwise suitably secured.

A layer of cement 32 is applied to the exposed surface of each of the panels 24, prior to the application of the next layer of panels. The cement 32 should be distributed over substantially the entire exposed surface of the panels 24, and be of. a depth to extend outward tiush with or beyond the outer surface of the binding members 30. This may be accomplished by trowelling on a smooth continuous layer of cement, or by utilizing a notched trowel to form spaced ridges of the requisite height, or the cement may be otherwise distributed in a continuous or discontinuous layer, so long as the resulting cement layer contacts the adjacent panels over substantially the entire area of their opposed surfaces after the overlying layer of panels 34 is pressed into place.

The second layer of panels comprising gypsum board panels 34 is then applied over the previously assembled structure, the panels 34 also being of a width to form overlap joints at each corner. The panels of this second layer will normally be held in position by the cement 32 previously applied to the exposed surface of the rst layer of the panels. Angle cover members 2Gb are placed over the corners of panels 34 to cover the joints therebetween and are secured in position by driving suitable fasteners 36a, such as metal screws, through the flanges of the angles 2Gb, through the underlying edges of panels 34 and through the flanges of the underlying angle members 26a. Flexible binding members 36, similar to members 30, are placed around the panels 34 and corner members 26b, drawn snug and secured, and a layer of cement 38 is distributed over the exposed surface of the panels 34 of this second layer in the same rnanner described above regarding cement layer 32.

Additional intermediate layers, such as the second layer of panels and related angle members, binding members and cement, may be applied in the same manner as the second layer.

The surface or finish layer construction is formed of panels 40 which are cut and applied to form overlapping edge joints as in the preceding layers. Corner members 26C are then applied over the corners in the same manner as the corner members 2Gb of the second layer, the corner members 26C being secured in place by fasteners 3612 extending through the flanges thereof, through the edges of the underlying panels 40 and through the flanges of the underlying corner members 26h. The anges of corner members 26C are then covered with joint cement 42 flush with the beads 29 of these members, and the cement feathered out over the panels 40 to provide a smooth planar appearing surface. The iinal la'yer of cement 42 provides a finished appearing surface to re- Ceive suitable decorative materials where desired.

The alternative construction illustrated in FIG. is the same as that illustrated and described with reference to FIGS. l-3 except that the final exposed layer of cement 44 covers the panels 40 to the depth of the beads 29 of the angle members 26C and provides the finished appearing external surface.

The cement utilized to adhere the various panels together and to finish and/ or cover the external surface of the outer layer may preferably be a joint compound, such as a casein or polyvinyl acetate base with a suitable filler, sometimes referred to as joint cement in the drywall industry. By way of example, suitable joint compounds are discussed in U.S. Letters Patent No. 3,003,979 to Ptasienski and Gill, and No. 2,047,982 to Page.

By way of one specic illustration of a construction embodying this invention, a steel column was covered in accordance with the disclosure in FIG. 5 utilizing panels about 5/8" in thickness and comprising paper covered cores of set calcined gypsum meeting Underwriters Laboratories, Inc., classification Wallboard, Gypsum Guide No. 40 U 18.23, and sold under the trademark Firecode by United States Gypsum Cornpany, Chicago, Illinois. The binding members were 18- gauge double strand steel wires of circular cross section, distributed over the length of the column at a maximum spacing of about 2l apart, and with a maximum spacing of about 6" from each end of the construction. The cover members were angular corner members of 26 gauge (U.S. Standard) galvanized steel with each ange being about l in width. The fasteners extending between pairs of overlying joint covering members were threaded, self-tapping rotary drywall metal fasteners of the type described in U.S. Letters Patent No. 3,056,234 to Nelsson and Knohl, about 1" in length, and placed on l2 centers along each cover flange. Joint compound sold under the trademark Perf-A-Tape by United States Gypsum Company of Chicago, Illinois, was utilized between successive panel layers and spread with a notched spreader to leave lines or rows of compound which were semicircular in cross section, with diameters of about 3/8, and on about ll/sl centers; this resulted in a compound bonding layer about 1746 thick after the overlying panels were secured in position. The outer sur-face finishing layer was also joint compound about le," thick.

When tested according to the aforenoted Underwriters Laboratories, Inc., test, the construction described above provided a tire rating of about 3 hours and 33 minutes.

The importance of the combination of features disclosed and claimed herein can perhaps best be illustrated by comparison of there rating test results on the foregoing example with the results of tests on other structures. For instance in three National Bureau of Standards tests on steel columns protected by layers of 1/2" thick gypsum board panels and joint compound between the panel layers, but without the metal corner joint covering members, the following results were obtained:

Test Construction Rated,

hours.

No. 315-5-22-52-4 Steel column protected with [our layers 2% layers. of VZ panels, fit with edge overlap and cut in lengths to cover the column height. Each layer applied vertically with joint compound to bond inner layer to column and successive layers to each other. Tied around the column with double strands of 18 ga. tie Wire spaced 15" apart after third layer is in place. Outer corners finished with joint compound and paper tape.

Steel column protected with three layers cut and applied as above except first two layers cemented and clinch-nailed together; then tied around column with double strands of 18 ga. tie Wire spaced 15" apart. Third layer then applied and outer corners finished with joint compound and paper tape.

Steel coltunn protected with two layers 1 cut and applied as in four layer construction above, except inner layer tied around column with double strands of 18 ga. tie wire, spaced 15 apart. Corners of face layer finished with joint compound and paper tape.

1% layers.

layers.

In other tests utilizing 5A thick gypsum board panels as designated above in the specific example of the present invention, together with metal angle corner joint covering members, but without cement between the panel layers, the following results were obtained under the aforenoted Underwriters Laboratories tests:

Test Construction Rated About 2 hrs., 33 min.

1-24-61-4 layers. Steel column protected with four layers of panels fit with edge overlap and out in engths to cover the column heights. Each layer applied vertically; the Iii-st and second layers each tied with VZ high tensile strength .015 thick metal straps spaced 2 apart. Corners of the second, third and fourth layers covered with metal angles, with screws fastening the angles of the third layer to the angles of second, and the fourth to the third. Outer corners and layer nished with joint cornpound.

Steel column protected With three layers of panels, tied around the two inner layers similarly to the four layer construction above except with 1'6" spacing from the oor slabs and 26 spacing between ties. Corners at the rst, second and third layers covered with metal angles, with screws fastening the angles of the second layer to angles of the first layer, and the third to the second. Outer corners finished with joint compound.

Steel column protected with three layers of panels, tied around the second layer with metal straps as in the four layer construction above except with 16 Spacing from the floor slabs and 26 spacing between ties. Corners at the second and third layers covered with metal angles, with screws fastening the angles oi the third layer to the angles of the second. Outer corners and layers finished with joint compound.

About 2 hrs., 33 min.

11-14-60-3 layers 9-16-60-3 layers About 2 hrs., 25

min.

The re rating of 3 hours and 33 minutes obtained with the construction according to the previously described specic illustrative embodiment of the present invention was thus one hour longer than the ratings of other laminated panel constructions, even though the other constructions included as many as three, or even four layers of panels.

It will thus be seen that a novel construction has been disclosed and taughtwhich utilizes inexpensive and readily available components to provide an advantageous high fire rating covering for structural elements. Further, the high iire rating constructions of this invention may be fabricated with the same components normally utilized in drywall constructions, thereby permitting the use of the same elements throughout the interior construction of a building and thus further enhancing the simplicity and economy of building construction.

While a particular embodiment of this invention is shown above and illustrated in the specific example, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made by those skilled in the art in light of the disclosure and teachings herein. It is contemplated therefore by the appended claim to cover any such modifications as fall within the true spirit and scope of this invention.

We claim:

A fire enduring construction enclosing a structural member, comprising rst, second and third successive superimposed layers of panels surrounding such structural member over its full exposed length, each of said panels Comprising a paper covered core of set calcined gypsum, said panels of each layer being disposed in edge-overlapping relation forming corners Where the edges of adjacent panels meet, said corners of successive layers being juxtaposed, a metal angle corner member secured over each corner of each layer, fastening members securing said cover members over said second and third layers to said cover members over said first and second layers respectively, a plurality of incombustible binding members eX- tending around said panels and cover members of each inner layer and distributed over the length of said construction, and layers of joint compound bonding said panels of said second and third layers to the panels of said rst and second layers respectively over substantially their entire area.

References Cited by the Examiner UNITED STATES PATENTS 646,503 4/ 1900 OShea 52-725 X 2,047,982 7/1936 Page 52-417 2,063,010 12/1936 Balduf 52-241 X 2,267,929 12/1941 Lefebure et al. 52-725 2,797,573 7/1957 Hummer 52-254 X 2,851,741 9/1958 Stemples 52-255 2,969,616 1/ 1961 Gustafson 52-278 X 3,05 6,234 10/ 1962 Nelsson et al 52-363 OTHER REFERENCES Architectural Forum (a publication), February 1952, page 22.

Building Materials List, published by Underwriters Laboratories Inc., January 1961, page 66.

FRANK L. ABBOTT, Primary Examiner.

JACOB L. NACKENQFF, HENRY C. SUTHERLAND,

Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,217,456 November 16, 1965 Paul S. Quigg et a1.1

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the sheet of drawings, line 2 of the heading, for "MUTI-LAYERED" read MULTI-LAYERED column 1, line 18, for "through" read though line 29, for "ATSM" read ASTM column 2, 1ines 15 and 16, for "incombustile" read incombustble line 69, for "artsens" read artisans column 5, in the table, second column, 1ine 3 thereof, for "engths" read lengths Signed and sealed this 13th day of September 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

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