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Description  |
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The present invention relates to an acoustical panel construction, and, in
particular, to an acoustical panel construction which enables the
fabrication of a finished panel capable of meeting the performance and
decorative demands of substantially any environment in which the panel is
installed.
The use of acoustical panels having high sound absorption properties and
resistance to fire, as well as other functional features, has been greatly
expanded in modern day construction, especially in office-type and
commercial buildings. Exemplary of acoustical panels which have attained
widespread recognition and acceptance among architects and builders are
the panels disclosed in U.S. Pat. Nos. 3,183,996 and 4,040,213. Panels of
this type are constructed in various sizes, the most popular sizes being
2'.times.2', 2'.times.4', 4'.times.4' and 5'.times.5'. The thickness of
the panels is generally from about 5/8 inch to about 11/2 inches. Mineral
fibers and glass fibers are, in the main, used as sound deadening
materials in the construction of such panels. Decorative facing materials
are provided for the exposed surfaces of the panels, and, in the case of
the panel disclosed in the aforementioned U.S. Pat. No. 3,183,996, a
metallic film is used as a backing to more effectively dissipate sound
enery, and, among other things, to reduce "breathing" through the panel.
The sound deadening or absorbing material employed in the manufacture of
such panels has a uniform density and thickness, and the finished panels
are formed by passing the sound absorbing material, together with the
other components which go to make up the completed panel, through an oven
where the bonding of the components of the panel is carried out. The
configuration, as well as the functional properties of the finished panel
are fixed when the panel exits from the oven. This practice, while
producing a high quality panel, does not lend itself to the fabrication of
acoustical panels capable of meeting the special needs of an environment
in which the panels are to be installed.
In accordance with the present invention, an acoustical panel construction
has been evolved which permits unique flexiblility and versatility in the
fabrication of an acoustical panel. The panel construction of this
invention can be customized or tailor-made to meet the performance
demands, from the standpoint of sound absorption, fire resistance, light
reflectance, heat barrier, decor, ease of installation, and overall
appearance, of substantially any environment in which the panel is to be
installed. Wholly apart from the unique customizing features of the
invention, the panel construction of this invention has sound absorption
properties which exceed those of conventional acoustical panels. Thus, for
example, panels constructed by the practice of the present invention have
noise reduction coefficients upwards of 1.05, whereas high quality
conventional acoustical panels have coefficients ranging from 0.50 to
0.95. What is more, these results are attainable at a cost comparable to,
and in certain cases, lower than that incurred in the manufacture of
standard acoustical panels in that the panel construction of this
invention incorporates more economical design features, and enables the
utilization of more economical materials.
The panel construction of the present invention, in brief, comprises a
preformed body portion or shell which establishes the configuration,
rigidity and the dimensions, except for the total thickness, of an
acoustical panel to be formed therefrom. The shell includes a central or
exposed area formed of an acoustical material having a predetermined
density and thickness. Joined to the central area of the shell are
outwardly extending edges by means of which the finished panel is
supported on a grid system. The edges are contoured to enable them to
conform exactly to a grid system thereby substantially reducing both any
sound transmission between the edges of the panel and the grid system, and
the double-line effect between the panel and the grid system which
characterizes conventional acoustical panel installations, and which
architects deem objectionable. The edges of the shell are formed of an
acoustical material, the density and thickness of which is such as to
impart the necessary rigidity and structural strength to the edges to
enable them to support a panel formed from the shell on a grid system
without any concomitant sagging or warping of the finished panel. The
exposed, or outer, surface, including the edges, of the shell
advantageously is provided with a facing of a desired color to compliment
the decor of the environment in which a panel formed from the shell is to
be installed. Apart from its decorative function, the facing adds to the
rigidity, dimensional stability and structural strength of the shell, and
can serve to effectively reflect, or absorb, light, and can enhance, or
augment, the sound absorption properties of the panel.
The central area of the shell is adapted to receive a pre-cut, or
pre-formed, sheet or batt of an acoustical material, the density and
thickness of which is preselected to meet the specific performance
requirements of an environment in which a panel is to be installed. The
sheet or batt of acoustical material desirably is provided with a backing,
especially a metallic backing such as a metal foil which, among other
things, imparts enhanced sound transmission properties to the finished
panel, while eliminating breathing and improving the thermal properties of
the panel. In accordance with one aspect of the invention, the edges of
the panels can be sealed and the metal foil can be wrapped around the
edges to completely seal the panels thereby to prevent dust and loose
fibers from entering the environment. This form of the panel construction
has special utility in rooms where computer, or other sensitive electronic
equipment, is kept.
The preformed body portion or shell of the panel construction of the
present invention can be fabricated in any size desired and conveniently
stored for future use. The ability to form a finished panel from the
preformed shell which will meet the performance demands of substantially
any environment in which the panel is installed also has important
economic advantages both from the standpoint of reduced material costs,
and simpler, less expensive manufacturing procedures in that molds instead
of high temperature operated ovens can be used to form the preformed shell
and the finished panel.
The foregoing, and other advantages and features of the panel construction
of this invention will become apparent from the description to follow
taken in conjunction with the accompanying drawings wherein:
FIG. 1 is a perspective, fragmentary view showing a ceiling installation
utilizing the panel construction of the present invention;
FIG. 2 is a perspective view of an embodiment of the panel construction of
the present invention;
FIG. 3 is a fragmentary, enlarged sectional view of an embodiment of the
panel construction of the present invention;
FIG. 4 is an enlarged fragmentary sectional view of another embodiment of
the panel construction of the present invention;
FIG. 5 is a fragmentary sectional view showing an embodiment of the panel
construction supported on a "T" rail grid or suspension system;
FIG. 6 is a fragmentary sectional view showing another embodiment of the
panel construction mounted on another form of a grid or suspension system;
FIG. 7 is an enlarged fragmentary sectional view of yet another embodiment
of the panel construction of this invention showing a body portion of
substantially uniform density and thickness;
FIG. 8 is a fragmentary, enlarged sectional view of an embodiment of the
invention incorporating a septum;
FIG. 9 is an enlarged fragmentary sectional view of another embodiment of
the panel construction; and
FIG. 10 is an enlarged fragmentary sectional view of an embodiment of the
panel construction showing the edges of the panel sealed.
Referring, now, in greater detail to FIGS. 3 and 4 of the drawings, the two
embodiments of the acoustical panel construction of this invention
illustrated, and designated generally by reference numerals 10 and 12,
respectively, each comprise a preformed, rectangularly shaped body portion
or shell 14. The shell 14 comprises a central or exposed area 16 formed of
an acoustical material having a predetermined density and thickness. The
area 16, as shown, is joined to, and preferably is integral with, stepped
edges 18, also formed of an acoustical material or predetermined density
and thickness, and desirably located on all four sides of the shell 14.
Each edge 18 of the shell 14 includes an inwardly extending section 18a
joined at substantially a right angle to an outwardly extending section
18b.
The preformed shell 14 can be fabricated of various acoustical, or sound
absorbing, and fire resistant materials, including mineral wools such as
slag or rock wool, glass fibers, as well as organic fibers, and synthetic
plastic spun or filament fibers, and mixtures of any of the foregoing.
Fire retardant materials such as antimony oxide or triphenyl antimony may
be incorporated in the material to increase its fire resistance. A
preferred material is a glass fiber laminate which has been impregnated
with an uncured, or partially cured, thermosetting bonding agent such as a
phenolic resin. In forming the shell 14, a sheet or batt of phenolic resin
impregnated glass fibers, for example, is compressed between the heated
platens of a suitably dimensioned press mold. Sufficient heat and pressure
are applied to the batt to form it into a self-supporting, rigid
structure. By way of illustration, a typical shell, such as the shell 14,
will comprise a central area 16 formed of phenolic resin bonded glass
fibers having a density in the range of about 2 to about 5, preferably
about 3 to about 4, pounds per cubic foot, and a thickness of the order of
about 1/4 to about 3/4, preferably about 1/3 to about 1/2 inch. The edges
of the shell advantageously should have a density in the range of about 5
to about 24, preferably about 8 to about 12 pounds per cubic foot, and a
thickness of about 1/16 to about 1/4, preferably about 1/8 inch. The
temperature of the heated platens used to form the shell can range from
about 350.degree. F. to about 450.degree. F., usually from about
375.degree. F. to about 400.degree. F. The pressures employed generally
will be of the order of about 250 to about 500 pounds per square inch. The
amount of pressure applied to the batt or layer of acoustical material to
form the shell 14 will be greater along the edges than in the central area
of the batt or layer to obtain the desired edge density and thickness.
As illustrated, the shell 14 is provided with a decorative surface or
facing 20. The facing 20 may be formed of open-weave natural or synthetic
fabrics, or combinations thereof, or the exposed surface of the shell may
be coated with a suitable latex-based paint. Preferred facing materials
are woven spun or filament plastics such as vinyls and polyesters, and
glass fibers. The weave of the facing should be such as to permit sound
energy to easily pass through it while at the same time having the
appearance of a solid, non-porous surface. An especially preferred
material is a glass fiber, textured fabric having a nubby, or roughened
surface. Such a facing material acts to augment the sound absorption and
light reflectance properties of an acoustical panel, while imparting an
attractive and interesting surface treatment to the panel. The thickness
of the facing material may range from about 2 to about 8 mils, but
preferably is about 4 to 5 mils.
The inner surface 16a of the central area 16 of the preformed shell 14 is
essentially parallel to the inner surface 18c of the outwardly extending
section 18b of the edges 18, but lies in a plane which intersects the
section 18a of the edge 18 thus forming a recess 22 in the shell 14 for
receiving a pre-cut sheet or batt or an acoustical material having a
preselected density and thickness. As shown in FIG. 3, the batt 24 of
acoustical material is positioned on the inner surface 16a of the central
area 16 of the shell 14, and the outer margins 24a of the batt 24 overlie
the inner surface 18c of the outwardly extending section 18b of the edges
18. In the embodiment of the panel 12 shown in FIG. 4, the pre-cut sheet
or batt 26 is sized to overlie the inner surface 16a only of the central
area 16 of the shell 14, and the outer margin 26a of the batt 26 partly
abuts the inner surface 18d of the section 18a of the edges 18 of the
shell. While the section 18b of each of the edges 18, as formed in
accordance with the practice of this invention, has sufficient rigidity
and structural strength to support a finished panel on any grid system,
the embodiment of the panel construction shown in FIG. 3 is preferred for
larger size panels to provide added structural strength and dimensional
stability to prevent sagging or warping of the panel.
The density and thickness of the acoustical material used in forming the
batts 24 and 26 may be selectively varied to meet the performance demands
of substantially any environment in which the finished panels are to be
installed. The generally optimum objectives of the invention are attained
with batts having a density of the range of about 2 to about 4, preferably
from about 2.5 to about 3, pounds per cubic foot. The thickness of the
batts can vary from about 5/8 inch to about 2.5 inches, usually from about
1 to about 1.5 inches. Again, as stated, the density and thickness of the
layers will be predetermined by the requirements of the room or other
enclosure, in which the finished panel is to be installed. The batts 24
and 26 may be formed of the same acoustical material employed to fabricate
the preformed shell 14. The practice of the invention, of course, enables
the use of a wide variety of fibers, both natural and synthetic, and
mixtures thereof, The batts advantageously are secured to the shell 14 by
means of a suitable adhesive. Where the batts comprise glass fibers
impregnated with a thermosetting bonding agent such as a phenolic resin,
the batts can be bonded to the shell 14 by applying pressure and heat to
the batt and the shell by means of heated platens of a compression mold.
The all around performance of the panel construction of this invention is
optimized by providing a backing sheet or layer 30 on the exposed surface
of the batts 24 and 26. In accordance with a preferred practice of the
invention, the backing sheet 30 comprises a metallic film, especially a
metal foil fabricated of a lightweight metal such as aluminum having a
thickness in the range of about 0.7 to about 2, preferably about 1 mil. A
glass felt sheet of similar dimensions can be used in lieu of the foil, if
desired. The sheet 30 may be bonded to the batts 24 or 26 by a suitable
binder such as a hot melt adhesive or a phenolic resin. The backing sheet
30 can be applied to the batts 24 or 26 under pressure and heat either
before, or at the time the batts are being bonded to the shell 14. As
disclosed in U.S. Pat. No. 3,183,996, the metallic backing sheet 30 acts
to reflect sound energy back into the batts 24 and 26 where it is
absorbed. The backing sheet also prevents sound energy from above the
panel from entering the panel, and thus insulates the area below the panel
from extraneous sounds. The backing sheet further acts to eliminate
"masking noise hot spots" thereby enabling the reduction of the number of
speakers required in generating the "pink noise" above the finished panel
in an open-plan office. This feature represents a significant cost savings
in the construction of such offices. The backing sheet additionally
reduces "breathing" through the panel, a condition which occurs when the
area above the installed panel is cooler than the area below whereby air
from the area below the panel would tend to be drawn upwardly through the
panel from the facing toward the back of the panel. In addition to heat
loss in the area below the panel this would tend to cause dirt to cling to
the facing of the panel. The backing sheet effectively prevents such air
passage through the panel. The backing sheet also provides an effective
thermal insulation barrier for the panel.
In FIGS. 5 and 6 of the drawing, the embodiments 10 and 12 of the panel
construction are shown supported on typical grid systems. The installation
shown in FIG. 5 is referred as a standard reveal installation in which the
panel 10 is edge supported on the transverse portion 40a of a "T" rail 40.
The vertical portion 40b of the rail 40 is supported from the ceiling of a
room. The grid system shown in FIG. 6 on which the panel 12 is edge
supported is referred to as a flush reveal installation, and comprises a
rail 50 having a vertical portion 50a which is supported from above, and a
U-shaped transverse portion 50b on which the panel 12 is engaged. The
multi-density panel construction of this invention enables the formation
of a panel which fits exactly to the configuration of the grid system on
which it is mounted. The close fitting arrangement between the panel and
the elements of the grid system on which the panel is mounted eliminates
the double-line effect usually seen with conventional panel installations,
and which is highly objectionable to architects. In addition, the close
fit achieved between the panel construction and the grid system
substantially prevents any passage of sound energy in either direction
between the edges of the panel and the supporting grid system.
In FIG. 1, a plurality of panels 60 constructed in accordance with the
teachings of this invention are illustrated as supported on a grid system
comprised of "T" shaped rails 62 and cross rails 64. The rails 62 and 64
are of the type shown in FIG. 5 of the drawing, with the vertical portion
thereof being supported from above the installation. The panels 60, which
are constructed like the panel 10 of FIG. 3, are edge supported on the
transverse portion of the rails, and can be readily positioned on and
removed from the grid system by tilting them in a known manner so as to
clear the rails. FIG. 2 illustrates one of the panels 50, comprising the
installation of FIG. 1.
The embodiment of the panel construction shown in FIG. 7, and designated
generally by reference numeral 70, like the panels 10 and 12 described
hereinabove, comprises a preformed body portion or shell 72. Unlike the
shells comprising the panels 10 and 12, the shell 72 of the panel 70 is
substantially uniform in thickness and density. The shell 72 is adapted to
receive a sheet or batt 74 of acoustical material, and is provided with a
decorative surface or facing 76. A backing sheet or layer 78 is bonded to
the batt 74. The panel construction 70 is referred to in the trade as a
"bold reveal" type panel. The thickness and density of the shell 72 and
the batt 74 may be varied as desired to provide a panel capable of meeting
the acoustical performance requirements of the environment in which it is
to be installed. The thickness and density of the edges, as delineated by
the letter "x", of the panel 70 can be varied in width and density to
impart the desired rigidity to the panel thereby enabling the panel to be
fabricated in any desired size. Generally speaking and by way of
illustration, for most installations, the density of the material
comprising the shell 72 will range from about 6 to about 20 pounds per
cubic foot, while the density of the batt 74 will vary from about 2 to
about 4 pounds per cubic foot.
The embodiment of the panel construction of this invention illustrated in
FIG. 8, and designated generally by reference numeral 80, comprises a
preformed shell 82, a batt 84 of acoustical material, a decorative facing
86 and a backing sheet 88 which may be a metal foil. The panel 80 differs
from the previously described panels in that it incorporates an additional
layer or septum 90. While only a single layer or septum is shown,
additional layers or septa may be incorporated in a panel construction to
achieve a desired result. The septum, or septa, as the case may be, serves
to enhance and augment the sound transmission characteristic (STC) of a
panel, as well as a means for providing an effective barrier to the
passage of dirt laden air through the panel. The septum may be formed of a
metal foil such as aluminum foil or lead foil, or it may be fabricated of
a synthetic plastic film such as vinyls and polyesters. Fiber glass or
glass felt sheets may also be used, as can sheets of a high density
mineral fiber. The thickness of the septum can range from 1 to 7 or 8
mils, more or less, depending upon the performance demands required of a
panel and advantageously will have dimensions conforming to the length and
width of the panel in which it is incorporated. As shown in FIG. 8, the
batt 84 is formed in two sections 84a and 84b to accommodate the septum
90. The septum 90 advantageously is adhered to the sections 84a and 84b by
means of a suitable adhesive material such as a thermosetting phenolic
resin.
The panel constructions shown in FIG. 9 of the drawings is referred to in
the trade as a "flush reveal" type panel. The panel, designated generally
by reference numeral 92, comprises a preformed shell 94 having a
preselected thickness and density, and a layer or batt 96 of an acoustical
material also having a predetermined thickness and density. As in the
previously described embodiments of the invention, a decorative facing 98
and a backing layer 100 are provided for the panel 92. The density of the
batt 96 along the edges of the panel and the width of the edges, as
represented by the letter "x", can be varied to impart the desired
rigidity to the panel. To this end, the outer edges 96a of the batt 96 ay
be subjected to higher pressures than the main body of the batt to achieve
greater densification of the acoustical material. Generally speaking, in a
panel such as the panel 92, the density of the material forming the shell
94 will be of the order of about 4 to about 14 pounds per cubic foot,
while the density of the edges 96a of the batt may range from about 6 to
about 20 pounds per cubic foot. If desired, the exposed surface of the
edges 96a can be provided with a coating 102 of a sealer, or the margins
of the backing layer 100 can be wrapped over the edges 96a to form a
completely enclosed panel for special installations such as clean rooms.
Exemplary of sealants which can be employed to form the coating 102 are
rubber latex adhesives, phenolic resins, neoprene cements, and polysulfide
based sealants, to name a few.
The panel construction illustrated in FIG. 10, and designated generally by
reference numeral 110, is a construction having special utility as a
"computer room" panel. The panel 110 comprises a preformed shell 112
formed of an acoustical material and having a density of the order of from
about 4 to about 14 pounds per cubic foot. A fabric or decorative film
facing 114 is provided for the shell 112. A layer or batt 116 is adhered
to the shell 112, and a backing layer 118, which may be a metal foil, is
secured on the outer surface of the batt 116. As in the case of the panel
92 shown in FIG. 9, the edges 116a of the batt 116 advantageously have a
greater density than the main body of the batt to impart the required
rigidity to the panel. Thus, by way of illustration, the edges 116a may
have a density ranging from about 6 to about 20 pounds per cubic foot,
while the main body of the batt may have a density of the order of about 2
to about 4 pounds per cubic foot. The exposed edges of the panel 110
desirably are provided with a coating 120 of a sealant, and then wrapped
with the backing material, as shown, to completely enclose the panel. This
edge treatment, in cooperation with the facing 114, serves to prevent dust
and loose fibers from above from entering the environment in which the
panel is installed.
As indicated hereinabove, panels constructed in accordance with the
practice of this invention have sound absorption properties which exceed
those of conventional acoustical panels. Thus, in tests performed with
acoustical panels of the present invention, noise reduction coefficients
ranging upwards to 1.05 have been attained as compared to coefficients of
0.50 to 0.95 for high quality acoustical panels presently being used.
These tests were based on conditions as set forth by the American Society
for Testing Materials for Sound Absorption of Acoustical Materials in
Reverberation Rooms under designation C42358T.
While for purposes of illustration representative embodiments of the
invention have been shown and described, other embodiments of the
invention may become apparent to those skilled in the art upon reference
to this disclosure and, accordingly, the scope of the invention is to be
determined by the appended claims.
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