US3504463A - Lay-in type suspended ceiling and panel therefor - Google Patents

Description

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LAY-IN TYPE SUSPENDED CEILING AND PANEL THEREFOR Filed Sept. 30, 1968 INVENTOR. DA V/D W AKERSON HIS ATTORNEY United States Patent Office 3,504,463 Patented Apr. 7, 1970 U.S. Cl. 52-145 9 Claims ABSTRACT OF THE DISCLOSURE In a lay-in type suspended ceiling, the acoustical panels are comprised of boards of mineral fiber bonded together with an hydrophilic binder, which boards are faced with a metal foil facing. Said foil facing being embossed.

This application is a continuation-in-part of my copending application Ser. No. 687,583 filed in the United States Patent Ofiice on Dec. 4, 1967.

This invention relates to a lay-in ceiling as distinguished from a tile ceiling.

One object of this invention is to provide an improvement in the lay-in panels faced with a metal foil as disclosed in my earlier application.

Another object ofthis invention is to provide a washable, and repeatedly washable, facing on lay-in panels, which facing also provides a damage resistant surface.

Still another object of this invention is to overcome the warping of the foil faced panels of my earlier invention when they are exposed to extremely severe variations in humidity.

These and other objects will be understood by those skilled in the art from the accompanying specification and drawings in which:

FIG. 1 is a prospective view from beneath of a lay-in ceiling, and

FIG. 2 is an enlarged view of a portion of one of the panels from FIG. 1.

Of the many types of ceilings currently being installed,

Commonly, lay-in ceilings incorporate panels or boards of a dimension of at least 2' x 2. In contrast, tile ceilings utilize tiles of generally 1' x 1', although sometimes such tiles are provided in 1' x 2' sizes.

Another distinguishing feature between the lay-in systems and tile ceilings is that the large panels of the lay-in ceilings are supported by resting upon a grid made up of runners and cross members which are of an inverted T shape in cross section. Thus the lay-in panels merely rest on the suspension system, which is generally referred to as an exposed system. In contrast, tiles are mounted in a number of ways Which do not normally expose the suspension system. Tiles may be nailed, screwed, or adhered to a completed ceiling, or they may be mounted in a suspension system specifically designed to hide the suspension system in kerfs cut into edges of the tiles.

Lay-in panels are merely square cut on their edges and extend in size, as indicated above, from 2' x 2 in dimension on up, with 2' x 4' being the most common dimen sion. Larger sizes are sometimes provided, but normally not in excess of 2' in Width. Thus, panels 2 x 5' and 2 x 6' are known.

The lay-in system generally enjoys a greater volume of sales in the industry, due largely to the lesser cost per square foot of producing a square cut board as opposed to one requiring additional working of the edges, such as is required with tiles. Another reason for the general economy of lay-in systems is the ease of installation and the minimum amount of suspension system needed.

For certain applications, however, lay-in panels were not acceptable prior to the invention disclosed in my earlier application. Generally, in areas of excessive humidity, such as restaurant kitchens, bathrooms, and swimming pool areas, a highly washable surface is required. For these types of applications, recourse has been had to tile systems in which the tiles are faced with a metal foil, generally extending at least part way up the edges of the tiles. Such metal foils serve to provide a hard and washable surface for such applications as mentioned above where repeated washing or sanitizing, such as in hospitals, is required.

As pointed out in my earlier application, previous to my invention disclosed therein, lay-in panels had not been provided with metal foil facings. It is not known exactly why such products had not been available; how ever, it is believed due to the fact that large panels tend to sag or pillow in the center, thus giving an undulating and unpleasing appearance to the ceiling.

Because of fire code requirements, most all lay-in panels are made from mineral fibers bound together with a suitable binder. The common binder is starch, which is hy-drophilic. Starch, of course, is used primarily for economy. When such panels are mounted in high humidity areas, being supported only at their edges, the humidity tends to weaken the starch bond, thus permitting the board or panel to sag noticeably toward the center. Any additional Weight added to the panel tends to aggravate this difficulty.

Even without added Weight, such mineral fiber panels bound with hydrophilic binders have required additional treatment such as a resin coating on the back side in order to bring the sag characteristics within acceptable limits. Until my invention disclosed in my earlier application, it was not to be expected that the added weight of metal foil facings could be tolerated, since metal foils are not in themselves self-supporting.

As disclosed in my earlier application, I discovered that foil faced mineral fiber boards with an hydrophilic binder could be produced which do not sag beyond acceptable limits. I have found, however, that panels so produced tend to warp in a different manner if exposed to extreme high humidity and then are subjected to more normal humidity, all as more fully described hereinafter.

In the drawings, FIG. 1 shows a suspension system for a lay-in system, including lay-in panels 10, longitudinal runners 12, and cross members 14.

The cross section of a runner 12 is shown in FIG. 1 as comprising a vertical web 16 and horizontally disposed flanges 18 and 20. The cross section of the cross members 14 is not shown but is substantially identical to the cross section of the runners 12.

The runners 12 are supported from a permanent superstructure, such as a concrete deck (not shown), by means of wires 22 fastened to such a deck at one end and at the other end to the web 16 of the runners 12.

It will be seen that the panels 10 merely rest upon the horizontal flanges 18 and 20 of the suspension system runners 12 and cross members 14. As such, the suspension system comprised of the runners 12 and the cross members 14 is exposed, at least to the extent of showing one face of the flanges 18 and 20. This arrangement permits the panels 10 to be removed by pushing upwardly, thus permitting access to pipes, duct Work, electrical conduits, and the like hidden above the suspension system ceiling and beneath the deck above. The ease of access is another of the reasons for the general popularity of this type of ceiling.

The panels of the instant invention are also shown in FIG. 2, wherein they are shown to comprise a body portion 24 and a metal foil facing member 26.

The body portion 24 is comprised of felted synthetic mineral fibers bound together by a suitable economic binder such as the hydrophilic binder starch. The facing 26 is preferably of aluminum foil but may be any of a number of other metal foils, such as tin, brass, stainless steel, and the like.

The metal foil facing 26 is preferably adhered throughout substantially its entire extent by means of an adhesive to the front surface of the body 24.

The panel 10 is also provided with relatively minute acoustical openings 28 punched through the metal foil 26 and into the body board 24. These acoustical openings are generally of a size between and in diameter. There are a myriad of such minute perforations in the front surface of the panel 10. These acoustical openings provide access into the sound absorptive body board 24 for acoustical energy-sound-impinging upon the face of the metal foil 26. The metal foil itself is, of course, not acoustically absorptive and the body board 24, in the absence of the openings 28, would not be particularly sound absorptive either. The openings 28 permit the sound to enter well into the body board 24, where the sound is absorbed in known fashion in the interstices of the fibers. Generally the fibers arrange themselves in layers parallel to the plane of the panel 10 and, consequently, some means of introducing the sound energy into the body of the board is required. However, these openings 28 also permit access into the interior of the board for the humidity of the atmosphere which deleteriously affects the hydrophilic binder.

In one accepted test for sagging, a ceiling of lay-in panels is supported in an enclosed tent, or room, where the humidity and temperature may be controlled. In such a test, the maximum permissible limit along the 4 length of a panel is 0.25" downward sagging. As disclosed in my earlier application, applicant has found, contrary to expectations, that with a metal foil facing such large panels will sag only between .08" and .10".

I have found, however, that when the panels of my earlier invention are exposed to exteremely high humidity and then are subsequently exposed to lesser or more normal humidity, while they do not sag excessively, they do warp in an unusual manner. Under such circum stances the board surface is not really very much below the level of the suspension system and falls well within the usually considered acceptable limit of 0.25" downward sagging mentioned above; however, the four corners of the board raise up from A" to /2" above the horizontal flanges of the suspension system. This creates a warped effect at the corners which is aesthetically disadvantageous. I have found that an embossed foil, preferably an embossed aluminum foil, of not in excess of .0025" in thickness overcomes this warping problem completely. Indeed, I have found that such a foil is so effective that it not only prevents the above-mentioned corner warping but also eliminates sag to such an extent that the normal resin coating on the back side of the board may be eliminated.

In the drawings the metal foil is shown as embossed as indicated at 30; however, it must be understood that the drawings are merely an attempt to show the embossing which is preferably of the type referred to as a stucco pattern by the foil supplier. Actually, various patterns of embossing will serve although an embossing extending substantially over the entire surface of the foil applied to the front surface of the board 24 is preferred.

I have also discovered that a foil of .0025" or less works well to eliminate such warping of the corners, and incidentally to improve the sag characteristics, whereas an aluminum foil that is embossed and which is .004" thick does not quite give the proper effect.

The examples of Table I were all prepared with a W base board of mineral fibers bound with starch and having the foil facings indicated above. The examples were all tested in the high humidity tent referred to above and the sag and corner warp values listed in Table I were thus obtained. It will be seen only those examples with embossed foils performed satisfactorily on both sag and corner warp while all examples were satisfactory with respect to sag. The most satisfactory corner warp examples were Examples III and IV having embossed foils of less than .004" thickness.

'It is not known, nor need it be known why embossed foils perform to give these results; however, it is theorized that there is an accordion effect in the foil such that it will expand and contract with the board, thus eliminating the application of additional stresses to the board surface when it is subjected to the extremes of humidity referred to above.

As indicated above, and as illustrated in the examples, it has been found that a resin coating, as often applied to the back side of the board, is not required when such thin embossed foils are used.

While reference has been made herein to dimensions of 2' x 2', 2' x 4, and larger for the panels 10, it is to be understood that in the industry these dimensions refer to what is called nominal dimensions and that actually such panels will be a few fractions of an inch smaller than the indicated sizes in order to accommodate the thickness of the web 16 and to permit insertion and removal of the panel 10. For example, the nominal 2' x 4' size, which is most common, is in actuality 111% x 311%".

By the term foil as used herein, applicant refers to metal foils which are of such a thickness as to be not selfsupporting in the dimensions referred to above, such as the nominal 2' x 2 size or larger.

I claim:

1. An acoustical panel comprising a board of mineral fibers bound together by an hydrophilic binder, said board having a substantially smooth planar face and being of at least substantially 2 x 2 in dimension in the major plane thereof, a metal foil facing adhered to said face of said board throughout substantially the full extent of said face, and said foil being embossed throughout substantially the full extent thereof with a pattern.

2. The panel of claim 1 in which said foil is less than about .004 in thickness.

3'. The panel of claim 1 in which acoustical Openings extend through said foil and into said board to provide access to the interior of said board for sound energy impinging upon the exposed face of said foil.

4. The panel of claim 3 in which said foil is less than about .004" in thickness.

5. The panel of claim 3 in which said board is free of any resin coating on the opposite face of said panel.

6. The panel of claim 3 in which the side edges of said board are substantially free of foil.

7. A suspended acoustical ceiling of the lay-in type comprising a suspension grid having a plurality of parallel runners and a plurality of cross members extending be tween runners, said runners and cross members being an inverted T shape in cross section, a plurality of acoustical panels supported horizontally by said grid with the edges of said panels resting on the horizontal flanges of said runners and cross members, each of said panels being comprised of mineral fibers bound together by an hydrophilic binder to form a board, the dimensions of each of said boards being at least substantially 2' x 2' in the plane of the ceiling, each of said boards having a substantially smooth planar face, a metal foil facing adhered to said face of said board throughout substantially the full extent of said face, said panels being mounted in said suspension grid with their foil facing downwardly to- Ward the interior of the room, and said foil being embossed throughout substantially the full extent thereof with a pattern.

8. The panel of claim 7 in which acoustical openings extend through said foil and into said board to provide access to the interior of said board for sound energy 1 References Cited UNITED STATES PATENTS FOREIGN PATENTS 12/1965 Great Britain.

5 ALFRED C. PERHAM, Primary Examiner US. Cl. X.R.

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