GB1564709A

GB1564709A - False ceilings for suppression of sound transmission buildings

Info

Publication number: GB1564709A
Application number: GB46984/76A
Authority: GB
Original assignee: Armstrong Cork Co
Current assignee: Armstrong World Industries Inc
Priority date: 1975-11-11
Filing date: 1976-11-11
Publication date: 1980-04-10
Also published as: DE2550663C3; ATA741376A; FR2331651A1; NL7612340A; SE7611200L; DE2550663B2; BE847572A; CH610975A5; NO763716L; DE2550663A1; DK142957C; NL173083C; DK506276A; FR2331651B1; AT349184B; NL173083B; DK142957B; SE433096B

Abstract

Ceiling panels (21) consisting of sound-inhibiting and fire-retardant materials are borne by band rails (22), in a grid arrangement, to form a trelliswork. At the points of intersection, the band rails (22), in a grid arrangement, are suspended on the unfinished ceiling (A) by means of wires (23) and eyelets (24). Strips (28) consisting of the same sound-inhibiting and fire-retardant material are introduced into the channel-shaped band rails (22), in a grid arrangement, and upright, sound-absorbing panels (29) are inserted above said strips. The transverse spacing between the upright panels (29) is smaller than the spacing between the subdividing walls (E, F, G, H) of the room, said panels (29) ending at a distance from the unfinished ceiling (A). <IMAGE>

Description

(54) FALSE CEILINGS FOR SUPPRESSION OF SOUND TRANSMISSION IN BUILDINGS (71) We, ARMSTRONG CORK COMPANY, a Corporation organized according to the laws of the Commonwealth of Pennsylvania, Lancaster, Pennsylvania 17604, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to methods for suppression of sound transmission from room to room in buildings, having false ceilings which stretch uninterrupted over several rooms separated by partition walls, and to a false ceiling construction having reduced sound transmission characteristics.

It has long been recognised as a serious drawback of false ceilings which extend over several rooms, that sound produced in one of the rooms is transmitted into the intermediate space between the false ceiling and the structural soffit and from there into the neighbouring rooms. It is not generally possible to overcome this problem by extending the partition walls upwards beyond the false ceiling to the structural soffit, because in modern installations, used in particular for office, university, school and hospital buildings, it is intended that the false ceiling extends uninterrupted from supporting wall to supporting wall, whereas the partition walls beneath the false ceiling are capable of being moved in order to be able to adapt the floor plan to changing requirements by repositioning the movable partition walls.

Attempts have been made to reduce the transmission of sound from room to room through the hollow space above the false ceiling, in such buildings by laying a layer of sound-absorbent material, such as mineral wool matting, on the panels of the false ceiling. This is expensive and also has extremely dangerous disadvantages which have not so far been generally recognised.

While the sound absorbing layer does indeed reduce the transmission of sound produced in one room into the hollow space between the ceilings and thus also reduces the transmission of this sound into a neighbouring room the layer also has a heatinsulating action which has serious consequences. On the one hand in the case of fire because of the heat insulating action the destruction of the false ceiling by the action of the fire is inadmissibly accelerated.On the other hand, because of the insulation of the hollow space between the ceiling the rooms are kept cooler than they would normally be as a result of which cables and pipes laid in the hollow space between the ceiling may freeze up, and, in particular in the case of structural soffits which also form the roof of a building, the position of the condensation point may be shifted so that it lies inside the hollow space between the ceilings instead of remaining in the load-bearing ceiling as correctly planned.

This type of sound absorption by means of layers of mineral wool laid on the false ceiling panels is described for example, in "Report No. 11, 1975" of the "Institut für Bauphysik der Fraunhofer-Gesellschaft" (Institute of Architectural Physics of the Frauhnhofer-Gesellschaft).

I his invention provides a form of ceiling by which effectively transmission of sound from room to room is suppressed in buildings in which a false ceiling extends continuously over several rooms formed by movable partition walls which extend only as far as the false ceiling, which does not rely on applying a layer of sound, and therefore heat insulating material, and therefore considerably reduces the costs incurred by applying mineral wool matting.

The invention provides a false ceiling, for the reduction of sound transmission between rooms formed by partition walls which extend only up to the false ceiling, comprising a plurality of horizontal ceiling panels and a plurality of vertical sound absorbent panels forming a honeycomb structure arranged on the upper side of the horizontal ceiling panels, the transverse distance between adjacent parallel vertical panels being less than the distance between the room partition walls adjoining the underside of the ceiling, and the vertical panels not extending right up to the structural soffit.

The transverse spacing of the vertical panels will depend on the size of the rooms which it is desired to insulate but the spacing should preferably be small compared with the size of the rooms so that as little uninterrupted horizontal ceiling panel as possible is present above two adjoining rooms.

The vertical panels are preferably mounted on the grid runners supporting the horizontal ceiling panels.

In a particularly advantageous form of the invention the vertical panels are not only arranged in the intermediate spaces between displaceable partition walls but are also located above and along the partition walls. This can be arranged when the partition walls lie beneath grid runners for the horizontal ceiling and the vertical panels are supported by the said runners.

The invention also provides a building fitted with at least one such false ceiling.

The invention further provides a method of reducing sound transmission in a building through the space between a false ceiling and the structure soffit which comprises fitting the building with one or more false ceilings according to the invention.

Four forms of false ceiling constructed in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic isometric view, partially in section, of a part of a building with the first form of false ceiling; Fig. 2 is a fragmentary, isometric view of a part of the false ceiling of Fig. 1; Fig. 3 is a fragmentary sectional view on a larger scale of a detail of the ceiling shown in Figs. 1 and 2; Fig. 4 shows in sectional elevation the second form of ceiling, which is a modification of that shown in Figs. 1 to 3; Fig. 5 shows in sectional elevation the third form of false ceiling; Fig. 6 is an enlarged, fragmentary sectional view of a detail from Fig. 5; and Fig. 7 shows in sectional elevation the fourth form of ceiling.

The construction illustrated in Fig. 1 comprises: a structural soffit A; vertical supporting walls B spaced from each other; a load-bearing intermediate floor C; a false ceiling D; partition walls E, F, G, H partly adjoining one another and partly adjoining the supporting walls, the partition walls separating the space between walls B into individual rooms or passageways I. J. K.

As is shown in Figs. 1 to 3, the false ceiling D consists of horizontal ceiling panels 21 which are supported by intersecting grid runners 22, the latter being suspended at their points of intersection by means of wires 23 and eyelets 24 on the structural soffit A. The construction of the runners may be of any construction capable of supporting a vertical ceiling panel, for example they may be constructed in the manner specified in the Applicant's DOS 25 16 845. The ceiling panels 21 are soundimpeding and fire-resistant and may as usual be formed from a mixture of fibres, bonding material and filling agents.

The runners 22 are channel sections, which are open at the top, and have a base wall 25, side walls 26 and horizontal flanges 27 extending the base wall and serving to support the panels 21. Narrow strips 28 of the same fibre-board material as the ceiling panels 21 are preferably inserted in the channel of runners 22. Up to this point this is a construction as disclosed in DOS 25 16 845.

Vertical panels 29, preferably made of mineral wool, are now inserted into the channels of the grid runners 22 so that an uninterrupted honeycomb construction extending over the entire false ceiling D is produced.

The thickness of the panels 29 is, for example, 60 mm and their height, for example, 20 to 30 cm. The density of the sound-impeding or sound-absorbent' mineral wool panels may be about 15 kg/m3 to 16 kg/m3, for example; such panels are like a loose, soft felt. They are supplied for example by the firm of Griinzweig & BR< Hartmann under the name of "Isoverplates W".

By the vertically arranged mineral wool panels 29 a considerable improvement in the sound transmission characteristics of the ceiling is obtained with only a slight increase in weight; the sound absorption of the ceiling is adequate for almost all fields of application. The height of the mineral wool panels 29 depends on the acoustic requirements and the architectural opportunities, and may be varied. Thus with panels 20 cm high a sound absorption of 47 dB was obtained and with panels 30 cm high a sound absorption of 51 dB. The spacing of the panels 29 in longitudinal and/or transverse direction depends on the spacing of the grid runners 22, which is normally 1.2 metres.

When greater demands are made for sound absorption, or when the distance between the horizontal ceiling and the structural soffit is very large or very small, additional strips or panels 30 of mineral wool may be placed above the vertically arranged mineral wool panels 29 in one direction or in intersecting directions, as shown in Fig. 4 of the drawings. In such cases the thickness and width or the spacing between the horizontal mineral wool panels 30 depends on the acoustic requirements and architectural opportunities.

Referring now to Figs. 5 and 6, the soundabsorbent and/or fire-restrictive fibre-board panels 31 of the third form of false ceiling are supported by narrow grid runners 32 which have the shape of an inverted "t".

The vertical mineral wool panels 33 are supported on these runners by mounting brackets which are open at the top, or Ushaped bars 35. These brackets or bars are secured by means of a downwardly directed arm 36 to the web 37 of the T-runner 32. The brackets or bars 35 may also be made up of two Z-shaped parts adjoining each other with one of their arms.

In this arrangement as in the arrangement of Fig. 4 additional sound absorbency can be achieved by placing horizontal mineral wool panels 34 on top of the vertical panels 33.

To permit the ceiling panel 31 to be swung out, as shown in Fig. 5 by a chaindotted line, the brackets or bars 35 are secured off-centre of the web 37 of the Trunners 32 in such a manner that on only one side (the left side in Fig. 5) do the brackets or bars 35 project considerably into the grid compartment, whereas on the other three sides of the grid compartment they only project slightly beyond the web 37 of the T-runners 32 towards the middle of the grid compartment, thus permitting the ceiling panel 31 to be swung upwards about the edge adioining the left-hand T-runner 32.

Of course, the ceiling panel 31, cannot be removed easily in all the neighbouring compartments. The simplest system would comprise permitting alternate rows of panels 31 to be removable, whereas the intermediate rows are unremovable in this manner. In such an arrangement, it will normally be possible to gain access to cables, lighting fixtures etc. in all the grid compartments.

Referring now to Fig. 7, in the fourth form of ceiling inverted T-shaped runners 40 similar to the runners 32 of the construction described in relation to Fig. 5 and 6 engage in known manner with their horizontal arms or flanges in peripheral grooves in the ceiling panels 41, so that the runners are concealed by the ceiling panels.

In this construction it is normally impossible to remove the ceiling panels unless the panels or runners are specially constructed or at least one panel can be destroyed. The sound-absorbent mineral fibre panels 42 may therefore be held by brackets or bars 43, open at the top, which are centrally disposed on the bars 40.

It should be mentioned that to remove the panels 31 in the case of the embodiment illustrated in Figs. 5 and 6, the horizontal absorbent panels 34 when present, also have to be arranged off-centre, as illustrated in Fig. 5.

As illustrated in Fig. 7, an absorbent panel 42 is provided only on every second supporting runner 40. Of- course, if an adequate sound absorption could not be obtained otherwise, an absorbent panel can be arranged on each bar, and as shown in Fig. 4, absorbent panels could also be centrally positioned on the vertical absorbent panels 42.

WHAT WE CLAIM IS: 1. A false ceiling for the reduction of sound transmission between rooms formed by partition walls which extend only up to the false ceiling, comprising a plurality of horizontal ceiling panels and a plurality of vertical, sound-absorbent panels forming a honeycomb structure arranged on the upper side of the horizontal ceiling panels, the transverse distance between adjacent parallel vertical panels being less than the distance between the room partition walls adjoining the underside of the ceiling, and the vertical panels not extending right up to the structural soffit.

2. A false ceiling as claimed in claim 1, wherein horizontal, sound-absorbent panels, which extend only over a part of the area between neighbouring vertical panels, are placed on top of the vertical, soundabsorbent panels.

3. A false ceiling as claimed in claim 2, wherein the horizontal, sound-absorbent panels are placed centrally on the intersections of the vertical, soundabsorbent panels.

4. A false ceiling as claimed in claim 2, wherein the horizontal, sound-absorbent panels are placed only on parallel vertical, sound-absorbent panels.

5. A false ceiling as claimed in claim 2 or claim 4, wherein each horizontal, soundabsorbent panel lies with one of its edges on a vertical, sound-absorbent panel.

6. A false ceiling as claimed in any one of claims I to 5, wherein the vertical, soundabsorbent panels are inserted in the flatbottomed grid runners open at the top and supporting the panels of the horizontal false ceiling.

7. A false ceiling as claimed in any one of claims 1 to 5, wherein the horizontal ceiling panels are supported using inverted Tshaped runners, and U-shaped brackets or bars which are open at the top are fastened to the webs of the T-runners, and serve to accommodate the vertical sound-absorbent panels.

8. A false ceiling as claimed in claim 7,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. cases the thickness and width or the spacing between the horizontal mineral wool panels 30 depends on the acoustic requirements and architectural opportunities. Referring now to Figs. 5 and 6, the soundabsorbent and/or fire-restrictive fibre-board panels 31 of the third form of false ceiling are supported by narrow grid runners 32 which have the shape of an inverted "t". The vertical mineral wool panels 33 are supported on these runners by mounting brackets which are open at the top, or Ushaped bars 35. These brackets or bars are secured by means of a downwardly directed arm 36 to the web 37 of the T-runner 32. The brackets or bars 35 may also be made up of two Z-shaped parts adjoining each other with one of their arms. In this arrangement as in the arrangement of Fig. 4 additional sound absorbency can be achieved by placing horizontal mineral wool panels 34 on top of the vertical panels 33. To permit the ceiling panel 31 to be swung out, as shown in Fig. 5 by a chaindotted line, the brackets or bars 35 are secured off-centre of the web 37 of the Trunners 32 in such a manner that on only one side (the left side in Fig. 5) do the brackets or bars 35 project considerably into the grid compartment, whereas on the other three sides of the grid compartment they only project slightly beyond the web 37 of the T-runners 32 towards the middle of the grid compartment, thus permitting the ceiling panel 31 to be swung upwards about the edge adioining the left-hand T-runner 32. Of course, the ceiling panel 31, cannot be removed easily in all the neighbouring compartments. The simplest system would comprise permitting alternate rows of panels 31 to be removable, whereas the intermediate rows are unremovable in this manner. In such an arrangement, it will normally be possible to gain access to cables, lighting fixtures etc. in all the grid compartments. Referring now to Fig. 7, in the fourth form of ceiling inverted T-shaped runners 40 similar to the runners 32 of the construction described in relation to Fig. 5 and 6 engage in known manner with their horizontal arms or flanges in peripheral grooves in the ceiling panels 41, so that the runners are concealed by the ceiling panels. In this construction it is normally impossible to remove the ceiling panels unless the panels or runners are specially constructed or at least one panel can be destroyed. The sound-absorbent mineral fibre panels 42 may therefore be held by brackets or bars 43, open at the top, which are centrally disposed on the bars 40. It should be mentioned that to remove the panels 31 in the case of the embodiment illustrated in Figs. 5 and 6, the horizontal absorbent panels 34 when present, also have to be arranged off-centre, as illustrated in Fig. 5. As illustrated in Fig. 7, an absorbent panel 42 is provided only on every second supporting runner 40. Of- course, if an adequate sound absorption could not be obtained otherwise, an absorbent panel can be arranged on each bar, and as shown in Fig. 4, absorbent panels could also be centrally positioned on the vertical absorbent panels 42. WHAT WE CLAIM IS:

1. A false ceiling for the reduction of sound transmission between rooms formed by partition walls which extend only up to the false ceiling, comprising a plurality of horizontal ceiling panels and a plurality of vertical, sound-absorbent panels forming a honeycomb structure arranged on the upper side of the horizontal ceiling panels, the transverse distance between adjacent parallel vertical panels being less than the distance between the room partition walls adjoining the underside of the ceiling, and the vertical panels not extending right up to the structural soffit.

8. A false ceiling as claimed in claim 7,

including a rectangular grid compartment along at least three sides of which the Ushaped bars do not prqject, or only slightly project, into that compartment, so that the ceiling panel in that grid compartment can be swung up about the fourth side of the compartment.

9. A false ceiling as claimed in any one of claims I to 8 wherein the sound-absorbent panels are made of soft, loose mineral wool material.

10. A false ceiling as claimed in claim 9, wherein the mineral wool panels have a density of from 15 to 16 kg/m3.

11. A false ceiling substantially as hereinbefore described with reference to, and as shown in, Figs. I to 3, or Figs. 5 and 6, or Fig. 7 of the accompanying drawings.

12. A false ceiling substantially as hereinbefore described with reference to, and as shown in, Figs. I to 3 of the accompanying drawings. modified substantially as herein before described with reference to, and as shown in, Fig. 4 of the accompanying drawings.

13. A building fitted with at least one false ceiling as claimed in any one of claims I to 12.

14. A method of reducing sound transmission in a building through the space between a false ceiling and the structural soffit which comprises fitting the building with one or more false ceilings as claimed in any of claims I to 12.