Abstract: Because the present invention is the floor of the room which is made by laminating a porous expanded resin plastic sheet (2), a bulgy-and-hollow or undulating plate (3), and a porous expanded resin plastic sheet (2′) on a concrete slab (1), and then by plastering the surface of the expanded resin plastic sheet (2′) with mortar (4), it has the effect to improve the efficiency of sound insulation.

Abstract: A method of assembling a frame assembly for a partition system is disclosed. The frame assembly includes a partition panel, a fabric covering the panel, and a frame component. The frame component automatically and evenly tensions the fabric about the panel. The frame component provided according to this method includes a support element, a lockable element, and an integral hinge defined between the support and lockable elements. The support element defines a cavity for receiving and supporting the panel. The lockable element extends from and is moveable relative to the support element. The panel is inserted into the cavity, and the fabric is mounted to the lockable element. Next, the lockable element is moved about the integral hinge such that the fabric mounted to the lockable element is automatically and evenly tensioned about the panel. A backing strip may be mounted to the frame component to protect the fabric from the integral hinge.

Abstract: A structural panel for use in building structures or in the formation, finish or decoration thereof includes an outer sheet and a connector sheet with a plurality of collapsible or compressible dividers therebetween. The panel in a rest condition is expanded and of a desired thickness for final use but can be compressed into a relatively thin thickness or profile for shipping purposes. The panel is very lightweight but structurally strong and can be selectively bent in one transverse direction if desired. The panel can be easily cut or formed into any predetermined size or shape.

Abstract: A sound absorbing structure including a sound absorbing member, an air layer, and a resonant sound absorbing structure. The air layer is formed in the rear of the sound absorbing member. The resonant sound absorbing structure includes a slit and is formed in the rear of the sound absorbing member. The sound absorbing member is a surface plate covering the rear air layer and the resonant sound absorbing structure, and the sound absorbing member is shaped in one of a plate and plane.

Abstract: Building component assemblies include a sound-deadening board having defined compressional stiffness positioned between a framing member and an assembly board.

Abstract: A sound barrier wall system for reducing the transmission of noise into residential and commercially sensitive areas. The sound barrier wall system includes a partition member having a plurality of rib members and a rear wall, and a plurality of support members positioned about the distal ends of the partition member. The partition member includes an upper slot and a lower tongue for allowing interlocking with adjacent partition members. The plurality of rib members extending from the rear wall form a sound dampening surface that breaks up the sound waves and deflects the sound waves away from a residential area. A plurality of cavities preferably extend into the inner surface of the rear wall of the partition member for further increasing the sound dampening capabilities.

Abstract: A invention relates to a ceiling element (1) for a ceiling (D) consisting of several ceiling elements, comprising a lower metal support (4) which is divided up by links (7) and has holes; and an active sound layer (5) which is arranged in the metal support. The layer is a sound insulation layer or a sound absorption layer for example, especially in the form of an open-pore foam such as a melamine-resin foam. The active sound layer (5) is bonded to the metal support (4). According to the invention, the adhesive (6) is only applied to the link areas (11) and only the inner surfaces of the link areas (11) are bonded. This guarantees a simple, economical construction.

Abstract: A construction beam includes a pair of lateral members and a resilient web extending therebetween, so as to present a cross-sectional profile corresponding to commonly used construction beam members (e.g., 2″×4″ or 2″×6″). The resilience of the web helps to attenuate sound transmission through the beam from one lateral member to the other. In particular, in a wall frame, the lateral members are mounted at opposite ends thereof to end plates consisting of other construction beams according to the present invention (i.e., a pair of lateral members with a resilient web extending therebetween). The resilient web according to the present invention is conveniently made from a unitary piece of material. When the wall frame is used in a building structure, the lateral members of the end plates on the same side are attached to the surrounding structure, leaving the other side of the frame resiliently free floating.

Abstract: An aircraft engine run-up hangar comprises a building defining a test chamber capable of receiving an aircraft therein, an air inlet structure, and an exhaust structure. The air inlet structure is formed in a front end part of a roof structure corresponding to a front end part of the building. The exhaust structure is connected to a rear end part of the building and defines an exhaust passage extending obliquely upward from the back end of the building. A ceiling included in the building has an inclined section sloping down backward to straighten air currents, and a groove is formed in a middle part, with respect to width, of the inclined section to permit a vertical tail fin of an aircraft to pass when the aircraft is carried into or out of the test chamber.

Abstract: A foam-type acoustic panel is designed to be mountable on a stand having a shaft. The acoustic panel includes a main body portion. The main body portion has a first end, a second end, a front surface, a rear surface, a top surface, a bottom surface, and first and second interlocking members. The first and second interlocking members define a multi-segment cut that extends between the top and bottom surface. The multi-segment cut includes a first end disposed at one of the front and rear surfaces, and a second end disposed interiorly of the other of the front and rear surfaces. The second end of the multi-segment cut defines an elongated aperture extending between the top and bottom surface for receiving a shaft of a stand.

Abstract: A resiliently flexible construction beam includes a pair of lateral flange portions and a web extending therebetween, preferably, but not necessarily, so as to present a cross-sectional profile corresponding to commonly used construction beam members (e.g., 2″×4″ or 2″×6″). The resilience of the beam helps to attenuate sound transmission through the beam from one lateral member to the other. In particular, in a wall frame, beams according to the present invention are mounted at opposite ends thereof to end plates. In one example, the end plates include slits into which the webs of the beams can be received. The resilient web according to the present invention is conveniently made from a unitary piece of material such as, for example, steel.

Abstract: The power generator unit includes a container having an acoustically insulated inner wall. The inner wall has wall panels each provided with a number of spaced-apart vertical retention studs between which acoustic panels are installed. The retention studs have a cross-sectionally C-shaped main body from which laterally and outwardly extend wing flanges. The acoustic panels are retained against the wall panel by the wing flanges which overlap the side edge portions of the acoustic panels.

Abstract: A wall covering system including a pleated material, and the method of producing and installing the plated material. The pleated material includes a plurality of permanently fixed pleats extending in substantially parallel vertical relation to each other. Each pleat includes first and second pleat panels having first ends fixed by a securing line and opposing second ends defining an apex. The apex extends outwardly away from the wall as each pleat converges toward a center line extending between upper and lower portions of each pleat. The method of producing the pleated material includes passing a planar material successively through a pleating die and a securing device to initially form a plurality of pleats simultaneously and thereafter secure the plurality of pleats simultaneously.

Abstract: A die assembly for providing a gypsum ceiling tile having improved acoustic absorption properties includes a punch plate having punches which form perforations through a plasterboard tile and indentors which form indentations in the tile. The punches and indentors are arranged in elongate strips to produce fissure-like perforations and indentations. A stripper plate having apertures corresponding to the punches and indentors and a die plate having apertures corresponding to the punches sandwich the tile, and the punch plate is applied to the tile.

Abstract: Transportable steel module units and methods for assembling such units to form structures on site to create living and workspace building environments which are non-combustible and resistant to unhealthy contaminants, and high winds and other environmental conditions and wherein each module unit is substantially completely prefabricated and finished to permit immediate occupancy and predetermined use of a structure created by connection of two or more module units.

Abstract: The invention provides sound insulating panels for use in noise screens, the panels being formed from mineral wool of substantially uniform density and average density from about 100 to about 2000 kg/m3 and thickness not more than about 200 mm. These panels may advantageously be used in noise screens comprising one or two upright support members having I-profile cross-section of width greater than the panel thickness.

Abstract: The invention relates to a noise-protection wall-segment, for example for roads, motorways or railways and such like, said noise-protection wall-segment including transparent sheets, preferably a transparent plastic sheets, and means fixing the sheets. The transparent sheet is shaped around a perpendicular to the installation surface of the assembled noise-protection wall, the term ‘shaping’ being understood to mean vaulting and/or folding. Moreover, in the case of plastic sheets, preferably made of acrylic glass, threads of synthetic material can be embedded in the sheet which counteract splintering in the event of fracture and constitute a recognized bird impact protection device.

Abstract: This invention concerns a sound proof hangar for airplanes with a wide entrance (3) for aircraft (7). To provide a sound barrier at the open side, the entrance opening is limited, at least on one side, by a series of deflecting surfaces (10), the inner edges of which are directed, in horizontal section, towards the hangar interior and the external edges of which are directed laterally. The deflecting surfaces (10) can be moved between a closed position which partly or completely closes the entrance opening (3) and a position which opens the entrance opening (3).

Abstract: A protective barrier comprising a footing which is buried in the ground and supports a frame for supporting one or more panels. The panels internally comprise sound-deadening and/or air-filtering material and are constituted so as to have at least one finely perforated lateral surface, a finely perforated upper surface for collecting rainwater and a finely perforated bottom.

Abstract: A space-dividing wall panel system includes an improved acoustic and tackable cover pad. The cover pad includes an interior molded panel which is compressed about its peripheral edges wherein the compressed edge sections provide the required rigidity for the cover pad. While edge rails are provided in these edge sections, the edge rails are not rigidly connected to each other but instead are adhered to the molded panel. The edge rails are provided for mounting the cover pad to a wall panel frame and provide rigid edge areas to which a cover fabric is adhered. The molded panel is formed of a fiberglass having layers of a scrim material embedded therein for tackability. The molded panel further includes a compressed mounting region which has an increased rigidity to facilitate mounting of receptacle bezels thereto.

Abstract: A novel insulated wall structure is formed with upright hollow thermoplastic extrusions connected together in a row, with the extrusions presenting a row of compartments (15,22,30) adapted to receive concrete (39) extending along the length of the wall structure and a row of compartments (16,23,33) containing or adapted to receive insulation (38) material also extending along the length of the wall along side or in parallel with the row of concrete receiving compartments (15,22,30) whereby when the compartments (15,22,30) adapted to receive concrete (39) are filled with concrete (39) and the insulation (38) receiving compartments (16,23,33) are filled with insulation (38) the insulation (38) in said insulation (38) receiving compartments (16,23,33) is positioned to block heat transfer through the wall.

Abstract: The suspension and sound-insulation system is intended to be used in houses or buildings. In this system, a finishing panel is attached to a rigid structure surface by a plurality of rubber cylinders each provided with an open cavity extending axially. Each cylinder is attached to the structure surface by a suspension rod provided with opposite ends, which is inserted into the cavity of the cylinder and whose opposite ends are folded so as to extend the structure surface and be fixed thereto. The finishing panel is attached to suspension bars that are attached to the cylinders by other suspension rods passing through the cavities of the cylinders. The cavities of the rubber cylinders are axially offset and the cylinders are oriented during their installation in such a manner that their cavities are closer to the structure surface and to the suspension bars. The other suspension rods are also shaped and sized to receive and support one of the suspension bars.

Abstract: A core for the production of a rectangular acoustic panel includes a mat of rockwool bounded by flat front and rear surfaces, and having a density between 5 and 9 pounds per cubic foot, a thickness between 0.75 and 2.0 inches, and a binder content between 3% and 5%. A sheet of non-woven interbonded fiberglass is adhered to at least one flat surface of the rockwool mat, the sheet having a thickness between 20 and 30 mils.

Abstract: A molded fabric treatment includes an integral undercut or inturned peripheral flange for affixing the treatment to the structure to be treated. The treatments have a conventional, decorative, woven polyester fabric (of the type currently used in conventional office divider screen systems), or fabrics comprising other synthetic or natural fibers, bonded with adhesive to a relatively stiff moldable non-woven polyester fiber backing. The treatments are formed in a membrane or bladder press in which a flexible membrane presses the fabric and fiber composite against a form or mold that includes an undercut edge which, in cooperation with the press membrane, forms undercut flanges about the periphery of the treatment. The undercut or inturned flange may then be "snapped" over a corresponding mounting lip on the structure to be treated.

Abstract: In an acoustic building structure corresponding to the mass-spring-mass insulation principle, the two masses of the mass-spring-mass system are each formed of at least one rigid element (1,2) and are separated by at least one panel (4) of mineral wool combined with at least one air gap (5). The acoustic structure is such that the rigid elements (1,2) are trays with a U-shaped cross section and are lined on the inside of the U with at least one mineral wool (3).

Abstract: An out-of-doors prefabricated, pre-engineered vertical wall structure constructed entirely of pressure treated wood and comprised of successive individual wall sections tightly arranged in an end-to-end pattern. Supporting rectangular posts join immediately adjacent wall sections together end-to-end and occupy the entire space between the sections, each of the posts having flat surfaces facing the ends of immediately adjacent wall sections on opposite sides of the post with upright pairs of spaced cants secured to said flat surfaces so as to form upright channels extending upwardly from top to bottom on the posts, each pair of cants being spaced apart to receive one end of one of said wall sections in a tight relation between said cants.

Abstract: The acoustic tower of the present invention is a portable, acoustic tower that has both a performance position and a storage position. In the storage position, a canopy panel lies substantially parallel proximate an upper panel, both of which are hingedly secured to a cross tube assembly that is supported by a lift tube. The upper panel lies substantially parallel to a lower panel that is fixedly secured to a lower panel assembly having side supports and a center shaft which substantially contains the lift tube. To raise the acoustic tower to the performance position, the canopy panel is raised to one of a plurality of preset angles and maintained in position through use of ratchet and pawl assemblies of the cross tube assembly. With the canopy panel at the desired angle, the upper panel and canopy panel are raised vertically by telescopically elevating the lift tube within the center shaft. The lift tube is elevated by virtue of a winch assembly that is connected to the lift tube by a length of webbing.

Abstract: A sound insulating membrane and processes for forming, particularly well suited for use in floor, ceiling and wall constructions. The membrane comprises at least one backing layer in contact with a layer of nonfoam polymeric material. The polymeric material has an elongation factor of about 500% to about 900% and a Shore A hardness of from about 65 to about 80 points, 5 seconds. In a preferred embodiment, the polymeric material comprises 40-70% chlorinated polyethylene, 20-30% ethylene vinyl acetate, and up to 10% polyvinyl chloride. Floor, ceiling and wall constructions and related methods utilizing the sound insulating membranes are also disclosed.

Abstract: A sound absorbing hollow core panel of structural material based on Helmholtz resonator properties consisting of two exterior skins connected by spacers or structural connections and bounded by perimeter skins or structural connections with internal cavity or cavities that communicate with the exterior sound field through a plurality of orifices in one or both exterior skins as well as the perimeter of the panel and that have a plurality of Helmoltz resonators of different shapes and sizes tuned to specific frequencies that control the sound absorption characteristics of the hollow core panel. The internal cavity or cavities are defined by external skins and perimeters as well as internal structural elements acting as interior dividers, interior sub-volumes and perimeter structures, each of which may contain a plurality of orifices for sound communication forming a sequence of first order Helmholtz acoustical resonators with respective natural frequencies for sound absorption.

Abstract: A system for controlling acoustics and emissivity in an arena having a ceiling includes a pair of rollers mounted adjacent the ceiling and spaced apart over at least a portion thereof. A plurality of acoustics and emissivity controlling panels connected together to form a continuous sheet are mounted between the rollers for movement across the ceiling when the rollers are rotated. The panels include one having a high emissivity surface of at least 90%, one having a low emissivity surface of 7% or less and one having an acoustical surface with sound absorbing characteristics.

Abstract: A multilayered insulating panel having improved acoustic insulating properties and mechanical strength has two outer facings and a soft synthetic foam core having cavities. The foam core with the cavities is in intimate contact with the facings. The cavities are arranged so that the gaps between the core material and the outer facings are in alternate patterns with respect to the opposing outer facings.

Abstract: An arena includes a performance area and an audience area having a ceiling extending thereover. A plurality of first insulating elements having high acoustic characteristics and low emissivity are mounted in a portion of the ceiling extending over the performance area and a plurality of second insulating elements having high acoustical characteristics and high emissivity are mounted in a portion of the ceiling extending over the audience area.

Abstract: A structure comprising a group of wood columns (10) which are generally arranged in parallel such that any two adjacent wood columns (11) which are in flat surface contact with each other, tension members (20) consisting of a fiber-reinforced resin composite, which penetrate the group of wood columns (10) and clamp them in the arrangement direction such that the surface contact pressure between any two adjacent wood columns being from 2.0 to 28 kg/cm.sup.2. The columns themselves are not damaged and gaps do not form between the columns in winter due to shrinking and elongation. The number of parts is small, the columns can be simply assembled and the cost of production can be kept down.

Abstract: A sound-absorbing building panel for lining of the inside walls and ceilings, in particular ceiling tile, consists of a carrier panel to be arranged spaced from a wall, which carrier panel is advantageously a perforated sheet metal and to which on at least one side a sound-absorbing, microporous layer is applied. Such a building panel, which does not require an insulation layer as a backing and can, moreover, be manufactured inexpensively, has a sound-absorbing layer of granules which are surrounded on all sides by an adhesive coating. The granules are essentially designed ball-shaped and are adhesively connected together at point-like connections and to the carrier panel. The granules also have a diameter between 0.1 to 0.9 times of the hole diameter of the carrier panel.

Abstract: A permanent stud wall structure having improved sound transmission loss comprising two substantially parallel rows of spaced apart vertically extending support members secured at their ends to a base and header respectively by appropriate means and defining a stud cavity; said vertically extending support members being located in each of said rows such that there is a corresponding support member in the other row that is in substantially the same plane running perpendicular to said rows; one or more horizontally extending relatively rigid support members extending between one or more corresponding vertically extending support members and being secured to said vertically extending support members by appropriate securing means; said horizontally extending members including a vibration isolator means to reduce the transmission of sound between opposite ends thereof; and one or more layers of a covering material secured to the outwardly facing surfaces of one or more of said vertically extending support members s

Abstract: A shooting range having shooting booths with protective side walls constructed of an armour plate, soft metal framing studs running vertically along the armour plate, porous insulation material disposed between the framing studs and against the armour plate, and a sheet of sound-proofing tile attached to the framing studs and covering the porous material. The booths' ceiling is constructed of an armour plate meeting the upper edge of the armour plates of the side walls and a layer of sound-proofing tile extending between the side walls and located below and apart from the ceiling armor plate to define a space to accommodate the return end of a target transport system. The target carrier includes a two-prong target hook wherein the shaft and prong arms are formed detachable segments to facilitate replacement of a segment damaged by a bullet. The bullet trap includes a sand backstop having a reflected angle support structure to support a mound of sand.

Abstract: A noise barrier for use especially outdoors or by roadways. The barrier comprises two main components, namely a relatively light sound-insulating plane and a grating-like part which constitutes the outward appearance of the noise barrier. The sound-insulating plane is a carpet-like part disposed inside the grating-like part and hangs freely therefrom or from another support frame. The grating-like part screens the sound-insulating plane from view, and is designed such that neither accuracy nor an immobile foundation is needed in the mounting of the noise barrier in order to make its outward appearance acceptable. If the grating is made for example spiral and the plane folded or rolled up, the construction can be arranged in a small room for transport and unrolled when it is mounted. The noise barrier can also function as a crash wall.

Abstract: An acoustic panel system is provided for partially acoustically isolating a portion of a space in, for example, a recording studio. The acoustic panel system is modular in design and includes a plurality of different sized acoustic panels which can be assembled together in various configurations to form complete or partial acoustically isolated areas within a space. The acoustic panel system includes wall mount members, wall panels, floor panels, ceiling panels, transparent viewing panels and door panels. The wall mount members are basically partial members either permanently or removably interconnected with the walls of a space. The wall panels can be interconnected with the wall mount members. The wall panels may include casters for facilitating the movement thereof, and may also include feet for supporting the panels on uneven flooring.

Abstract: A reverberation room comprising walls, ceiling and floor having specific dimensions and spatial relationships used in an automotive testing laboratory to analyze sound for the purposes of measuring transmission loss and sound absorption. The room possesses two transmission loss test windows. One window is placed in the ceiling and one is placed in a side wall. Samples for testing can be mounted horizontally in the ceiling window. A rotating microphone boom is used in combination with the room to sample the sound field in the reverbration room and in reception chambers attached thereto. Three loudspeakers are also positioned in the room to generate the sound field in the reverberation room and indirectly in the reception chambers.

Abstract: This invention provides a thin metallic sheet structure having excellent sound damping characteristics which can lower the sound pressure level of a sound inherent to a thin metallic sheet structure when this structure is patted, and can quickly damp the sound by a simple structure. In a flat sheet-like or box-like structure comprising a thin metallic external sheet and beams for reinforcing the external sheet, a thin metallic sheet structure having excellent sound damping characteristics according to the present invention employs the construction wherein the reinforcing beams 2 are brought into contact with one of the surfaces of the thin metallic external sheet 1 through a sound damping sheet 3, and the coupling state between the sound damping sheet 3 and the thin metallic external plate 1 or the reinforcing beams 2 is a non-coupling state or a discrete coupling state on at least one of the surfaces of the sound damping sheet 3.

Abstract: A sound insulation pad for inhibiting sound transmission between floors comprised of thermoplastic material having a three-dimensional shaped surface. The invention also relates to a sound rated floor system using the sound insulation pad and a method of constructing such sound rated floor system.

Abstract: A new insulating tile for providing heat and sound insulation to wall and floor surfaces. The inventive device includes front and back plates each having inner and outer surfaces. Around the outer perimeter of the front plate is a side wall outwardly extending from its inner surface. The terminal edge of the side wall is coupled to the inner surface of the back plate to form a substantially air tight seal therebetween. The inner surfaces of the plate members are spaced apart to define an insulating interior space between them. A closure tab is outwardly extended from the inner surface of the front plate and is inserted into an aperture extending through the inner and outer surfaces of the back plate. The closure tab is designed for providing a substantially air tight closure of the aperture. The air pressure within the interior space is less than the relative air pressure of the environment surrounding the exterior of the insulating tile to provide further insulation properties to the interior space.

Abstract: The present invention relates to a self-supporting, sound absorbing interior surface panel comprising a non-woven fabric. The non-woven fabric may be laminated to a facing fabric using a heat activated thermoplastic adhesive, or the panel may be provided with a micro-porous top-coat finish. The panel of the invention may be provided with a vibration absorbent perimeter edge which may be shaped in an accordion-like fashion integrally with the rest of the panel, or manufactured separately of a flexible but resilient material and attached to the panel. The invention further relates to a suspended ceiling module comprising a support structure, such as a tee bar grid, and a panel of the invention which could be supported within the module in either tegular or coffered orientation. The invention also relates to a method of manufacturing the self-supporting interior surface panel.

Abstract: A curb for a rooftop air conditioning unit. The curb comprises: a frame having side walls and end walls arranged in a generally rectangular shape, and a generally planar portion overlaying a portion of the frame. The planar portion includes a first layer providing structural support, a second layer providing a sound barrier, and a third layer provides a heat energy barrier.

Abstract: A sound attenuating apparatus for noise bearing fluid streams wherein elongated perforated wall forming panel sheets include integrally formed indentations extending along a direction transverse the direction of the fluid stream to provide strength and stiffeners for the perforated panel sheets.

Abstract: A sound deadening wall assembly comprising a first wall panel attached to a first stud member, a second wall panel situated parallel to the first wall panel and attached to a second stud member, wherein the stud members abut each other with a resilient attachment material therebetween to secure the first and second stud members to each other. The stud members are of C-shape cross-section with the open end of the C-shape facing in opposite directions and abutting each other to create an overall S-shape when the stud members are joined together. Separable end and top members are also disclosed.

Abstract: Acoustical seating risers for indoor arenas are made of a plurality of pre-formed units of L-shaped cross-section. These L-shaped sections are mounted atop one another on a separate pre-formed foundation to provide a mounting platform for rows of seats and additional acoustical steps in the aisles. Each riser unit includes an integrally molded acoustical element having a slit and recessed chamber or a series of slits and recessed chambers designed to absorb low frequency sounds below 500 Hz, thus permitting balancing of the frequency response within that range. Riser units are assembled together in an overlapping fashion to form the sealed and slitted cavities and protect the recessed chamber or series of chambers from water or other contamination.

Abstract: The present invention provides an improved lighting fixture 10. The lighting fixture 10 is an acoustical lighting fixture which may be suspended below a deck 14. The lighting fixture 10 can be suspended below the deck by placing the fixture on a T-bar grid 16 of a drop ceiling 12. The acoustical lighting fixture 10 includes an acoustical shell 30 having an electrical light source 32, such as a fluorescent tube, removably mounted on the acoustical shell 30. The acoustical shell 30 may be constructed from a fiberglass material or a perforated metal material. The acoustical lighting fixture 10 also includes an acoustical, sound absorbing blanket 26 that absorbs sounds that strike the acoustical lighting fixture 10.The acoustical lighting fixture 10 may also include a louver 28 which encloses the electrical light source 32 within the acoustical shell 30.

Abstract: A building panel is formed using particulate mineral material, such as sand, with an adhesive binder, to form an aggregate. The mix undergoes a heating process to cure the adhesive, which also produces a porosity in the panel. The relative quantities of the materials are such that the resulting panel is porous after heating, with the interstices between particles being devoid of binder material. The resulting porosity provides for the limited passage of air and moisture, particularly water vapor, through the panels so the panels may "breathe" to allow circulation through a structure composed of the present panels, and also provides acoustic properties. The present panels are non-flammable, in accordance with the non-flammable materials used in the formation thereof. The panels may be colored or tinted as desired, by adding a coloring material (epoxy paint or other suitable coloring agent) which may be mixed with the sand and adhesive binder before heating.

Abstract: A false ceiling for buildings designed to absorb acoustic waves has perfoed plates. One or several suspended plates (1, 6) are provided which are so hard that they cannot vibrate. The plates have a plurality of regularly or irregularly arranged holes (4, 7) with 0.2-3 mm diameter, the surface of the holes being less than 4% of the total surface. The air in the holes (4, 7) forms with the overlying cavities (11) a dampening active mass system of the foil absorber type.