WO1997028330A1

WO1997028330A1 - Floor components and floor construction comprising such components

Info

Publication number: WO1997028330A1
Application number: PCT/GB1997/000261
Authority: WO
Inventors: Graham John Hilton
Original assignee: Monarflex Limited
Priority date: 1996-01-30
Filing date: 1997-01-30
Publication date: 1997-08-07
Also published as: AU1552797A

Abstract

A floor component is disclosed which includes a foam material made up of a mixture of open cell and closed cell foam particles. In one version of the component the foam material is attached to a rigid strip and a flexible web whereby the component may be attached to a flooring joist by means of the web so that floor boards can be laid on the component. In another version the foam is attached to an elongate batten to be laid onto an existing floor. The foam has acoustic and vibration insulating properties and can be used in the refurbishment of existing floors in hospitals and hotels, for example. A floor construction including a number of the floor components is also disclosed.

Description

FLOORCOMPONENTSANDFLOORCONSTRUCTION COMPRISINGSUCHCOMPONENTS

The present invention relates to a floor component. It relates particularly but not exclusively to a floor component having vibration and acoustic insulating properties.

In commercial and residential buildings, for example blocks of flats, office blocks, hospitals and hotels, it is known to refurbish an existing floor having a plurality of floor joists with a view to improving the acoustic insulation properties of the floor, by laying a new floor deck on top of the joists, there being a plurality of foam strips between the new floor deck and the existing joists.

A known foam strip comprises a first layer of open celled foam which is arranged to rest on top of a joist, a layer of closed cell foam which lays on top of the layer of open celled foam, a thin plywood strip, of thickness around 5mm, and a flexible web which extends laterally either side of the strip and is arranged to secure the foam strip to the joist.

The closed cell foam is directed at attenuating impact sounds for example as caused by shock loads on the floor. The open cell foam layer is directed at attenuating airborne sounds. Acoustic energy in the cavities between the joists is dissipated in the interstices of the open cell foam layer.

Typically, in known components of this type, the closed cell foam layer is of thickness 10mm, and the open cell foam layer is of thickness 12mm in unloaded state. When installed, under normal flooring loadings, the open cell foam compresses vertically, to a residual layer thickness of 8 to 9mm, whilst the closed cell foam layer remains substantially of the same thickness. This has the problem that the floor loading may affect the airborne sound attenuating properties of the open cells of the foam layer.

Another known method of floor refurbishment comprises laying onto an existing floor a sound deadening floor construction comprising a plurality of elongate wooden battens, for example of square cross-section 50mm x 50mm, on top of the existing floor and on top of the battens lay either floor boards, or tongue and groove chipboard floor panels. The wooden battens are faced on a lower surface with a strip of foam, such that the batten rests on top of the foam strip, the foam strip being in contact with the existing floor.

A known sound deadening floor construction of the above-mentioned type is disclosed in GB 2,192,913 in which there is provided a flooring raft construction comprising a plurality of floor boards nailed or screwed to a plurality of battens, each batten having on a lower face thereof, a laminated foam strip comprising a separate layer of higher density closed cell foam of thickness around 10mm, and a layer of lower density open cell foam of thickness around 10mm.

As with other know constructions, the closed cell foam is directed at absorbing low frequency vibrations, for example as caused by shock loads on the floor eg dropping a desk, jumping on the floor, or dropping some other heavy article on the flooring raft. The open cell foam layer is directed at absorbing higher frequency vibrations in the audible range. The open cell foam can absorb airborne acoustic vibrations by dissipation of the vibrations within the interstices of the open cell foam.

These known batten-type arrangements also have the associated problem that, in use, since the open cell foam is much less dense then the closed cell foam, the open cell foam may compress to less than its original thickness. For example a strip of open cell foam of height 10mm, may compress under loading to a much smaller thickness. The open cell foam layer compresses to a much greater extent than the closed cell foam layer. This may adversely affect the sound attenuating properties of the open cells of the foam layer and so of the floor construction as a whole.

According to a first aspect of the present invention there is provided a floor component comprising:

an elongate strip of foam material,

characterised in that said foam material comprises a plurality of open cell foam particles and a plurality of closed cell foam particles.

Preferably said open cell foam particles and said closed cell foam particles are mixed together in substantially random orientation.

Preferably said foam particles are mixed together to give a composition of 10% to 90% by volume of said open cell foam particles and 10% to 90% by volume of said closed cell foam particles.

Preferably said open cell foam particles and said closed cell foam particles are bonded together.

Preferably said foam material has a density in the range 50 to 120kgm^"3, and suitably in the range 75 to 95kgιrT³.

Preferably said foam material is of thickness in the range 10mm to 30mm, and suitably around 20mm.

Preferably said floor component is provided with attachment means for attaching said component to a floor joist.

Preferably said floor component has an elongate rigid strip bonded to said foam material.

Said rigid strip may be a timber or plywood strip.

Said rigid strip is preferably of thickness less than the thickness of a conventional floor board.

Said attachment means may be a sheet of material bonded between said rigid strip and said foam material and extending laterally to both sides of said foam material.

Alternatively the floor component may have an elongate batten on one side of said foam material. Preferably said foam material is adhered to one face of said batten.

According to a second aspect of the present invention there is provided a floor construction comprising:

a plurality of floor components each comprising an elongate strip of foam material; and

a plurality of floor boards on said flooring components,

Preferably said floor components are adapted for attachment to a respective flooring joist.

Preferably said floor components are positioned between said joists and said floor boards and each said floor component is attachable to the respective joist by a flexible web.

Preferably said web extends either side of said joist for attachment thereto.

Preferably said web extends between said foam material and said joist.

Alternatively said floor components may each have an elongate batten on one side of said foam material. The foam material may typically be adhered to one face of the respective batten.

Said floor components may be laid directly onto an existing floor surface without the need for attachment, and the floor boards laid onto the floor components.

Preferably said floor components may be laid such that said foam material is presented upwardly.

Preferably said floor boards may be adhered to one or more of said floor components.

The invention includes a floor construction comprising:

a plurality of floor components in accordance with the invention; and

a floor deck on said floor components.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig 1 is a perspective view of a first floor component in accordance with the present invention;

Fig 2 is a perspective view of part of a floor construction according to the present invention having the component of Fig 1 therein;

Fig 3 is a perspective view of a second floor component in accordance with the present invention;

Fig 4 is a perspective view of part of a second floor construction in accordance with the present invention having the component of Fig 3 therein;

Fig 5 is a perspective view of part of a third floor construction in accordance with the present invention having the component of Fig 3 therein;

Fig 6 is a graph of acceleration transmissibility against frequency for samples of reconstituted foam which may be used in the floor components of the present invention;

Fig 7 is a graph of input-output phase difference against frequency for the reconstituted foam samples of Fig 6; and

Fig 8 is a graph of theoretical values of transmissibility against the ratio of forcing frequency to natural frequency.

Referring to Fig 1 a floor component 7 comprises a foam layer 4 of reconstituted foam, a rigid strip 5 of thickness less than the thickness of a floor board, and typically around 6mm, and bonded between the foam layer 4 and the rigid strip 5, a plastics material web 6 extending either side of the foam layer 4. The rigid strip 5 is preferably plywood or timber.

Referring now to Fig 2 a floor construction comprises a flooring deck 1 made up of a plurality of floor boards 10, eg conventional elongate wooden floor boards or chipboard tongue and groove floor boards. The floor boards 10 are supported on a plurality of joists 2, the joists supporting a suspended ceiling 3, and between the floor boards 10 and the joists 2 a plurality of elongate floor components 7 as described above. Each floor component 7 comprises a layer of reconstituted foam 4 made up of a mixture of open cell foam particles and closed cell foam particles, the layer of foam 4 bonded to a rigid plywood strip 5 of thickness 3 to 7mm, and suitably around 6mm, and a flexible sheet web 6, suitably of a plastics material, the web bonded between the plywood strip 5 and the foam layer .

The foam layer 4 is placed between the floor boards 10 and the joist 2, and is attachable to either side of the joist 2 by, for example gluing or nailing the web 6 to either side of the joist 2 to secure the floor component 7 in position, and to prevent the floor component moving during fitting of the deck 1. The floor boards 10 may be glued directly to the foam layer 4. Suitably, the foam layer 4 has a thickness of around 18 to 20mm, and a width of 30 to 60mm and suitably 45mm.

In use, the flooring deck 1 comprising the floor boards 10 rests upon the reconstituted foam layers 4 and on the joists 2. Vibrations and shocks on the flooring deck 1 and acoustic noise produced by those vibrations and shocks are dampened by the foam layers 4.

Each foam layer 4 comprises a substantially randomly oriented mixture of open cell foam particles and closed cell foam particles, bonded together. The closed cell foam particles form support for the open cell foam particles. The open cell foam particles may absorb airborne acoustic vibration, and thus provide an acoustically insulating medium between the flooring deck 1 and the joists 2. The closed cell foam particles may absorb shock loadings on the floor, eg dropping heavy objects on the flooring deck, and reduce the transmission of shock loading vibrations to the joist 2. The foam particles may vary in size, but are suitably chopped up particles of reclaimed foam, which may have dimensions in the range 0.5mm to 20πtm. The particles of open cell foam and closed cell foam are bonded together to form a unitary foam layer, under conditions of elevated temperature and pressure above room temperature and pressure. A conventional bonding agent may be mixed in with the particles prior to subjecting to the elevated temperature and pressure.

The acoustic absorption and acoustic insulation properties of the foam can be varied by varying the proportion of closed cell foam particles to open cell foam particles. The density of the foam may be selected by varying the proportions of open cell to closed cell particles.

For example, the density of the reconstituted foam is of the order of 85kgm"³, and may be in the range 50- 120kgm^"3.

Referring now to Fig 3, a flooring component 21 according to the invention comprises an elongate timber batten 22 of substantially square or rectangular cross- section having width and height of comparable dimensions, for example 45mm x 45mm, or 45mm x 60mm. Along one face of the batten 22 is provided an elongate foam layer 23, the foam layer 23 being bonded to the batten 22 by a suitable adhesive.

The foam layer 23 comprises a reconstituted foam material formed of a plurality of particles of open cell foam material mixed substantially randomly with a plurality of particles of closed cell foam material. In this example, the foam material is the same as that of the floor component of Figs 1 and 2, as described above .

Referring now to Fig 4, a floor construction comprises a plurality of floor components 21 each as described above with reference to Fig 3, laid substantially in parallel to each other on an existing conventional floor surface 31, for example a concrete or wooden floor, and with the foam layers 23 underneath the battens 22. Laid on top of the plurality of floor components 21 is a floor deck 40 comprising a plurality of floor boards 42. Preferably the floor boards 42 are bonded directly to the battens 22 of the components 21. The foam layers 23 are preferably loose laid onto the surface 31, to allow some movement for expansion.

Referring to Fig 5, a floor construction comprises a plurality of the floor components 21 each arranged substantially in parallel, and laid upon a conventional flooring surface 41, eg a concrete or wooden floor. Each floor component 21 is as described above with reference to Fig 3. The floor components 21 are laid with the wooden battens 22 in direct contact with the conventional floor 41 and with the foam layers 23 on top of the battens 22. A floor deck 50 comprising a plurality of floor boards 52 is laid on top of the floor components 21, in direct contact with the foam layers 23. The floor boards 52 may be directly adhered to an upper surface of the foam 23 using a conventional adhesive.

With reference to the floor constructions of Figs 4 and 5, the respective floor deck 40, 50 and floor components 21 are secured to each other and form a raft which can move relative to the underlying original floor surface 31, 41. In the construction of Fig 4, impact vibrations can be absorbed between the battens 22 and the original floor 31.

In the floor construction of Fig 5, the floor deck 50 is isolated from the battens 22 by the foam strips 23 and vibrations can be absorbed by the raft comprising the floor components 21 and the floor deck 50.

Severe shock loading, for example by heavy weights falling on the floor boards of the floor construction are isolated from the underlying conventional floor by the reconstituted foam layers. As the reconstituted foam layer comprises a substantially homogenous, substantially random mixture of foam particles of open cell construction and closed cell construction, bonded together, the closed cell particles may absorb heavy shock loadings, whilst the open cell particles may absorb and/or attenuate higher frequency vibrations, such as general background noise, voices, audible noise from televisions or computer equipment.

The described embodiments of the present invention have the advantage that, because of the substantially random positioning of closed cell particles within the foam structure, the foam may have a more linear characteristic of compressibility against pressure loading than prior art laminate foams. Under shock load conditions, the homogeneous nature of the reconstituted foam may lead to reduced movement of the floor deck as compared to prior art floor constructions having the conventional dual layer laminate foam.

Under compression, primarily the closed cell foam particles bear the weight of the floor deck, and the open cell foam particles occupy the spaces between particles of closed cell foam. Because the open cell foam particles and closed cell foam particles are randomly interspersed and orientated, provided sufficient proportion of closed cell particles, and each of sufficient size are included, the open cell particles can be substantially prevented from compressing to a great extent and the interstices in the open cell foam can remain open to a greater extent under vertical loading of the floor, as compared with a prior art layer of purely open cell foam.

For an elongate foam layer, as used in the component of the invention, having width 45mm and height 20mm in uncompressed form, it was found experimentally that for an evenly distributed weight of 120kgm^~2, compression of the foam layer by 0.3 to 0.5mm was experienced. For a weight of 240kgm^"2, the foam layer compressed by 2mm + 0.3mm. For a weight of 360kgm"² the foam layer was found to compress by 4mm ± 0.5ram.

For a weight of 480kgm"^z, the foam was found to compress by about 5mm and for a weight of 600kgπT², the foam was found to compress by about 6mm, giving a compressed foam layer thickness of about 14mm.

For higher pressures, the foam layer compressed significantly. For a weight of 8750kgm^"2, the foam layer of 20mm thickness in uncompressed state was found to compress to a thickness of around 2mm.

Referring now to Fig 6, on a small scale laboratory test of a 20mm thick reconstituted foam layer, as compared with an 18mm thick reconstituted foam layer, a transfer function of acceleration transmissibility versus frequency was measured. The transfer functions for 20mm foam and 18mm foam are shown. A low transfer function, ie low value of acceleration transmissibility is desirable for isolation of vibration. for 20mm foam and 18mm foam are shown. A low transfer function, ie low value of acceleration transmissibility is desirable for isolation of vibration.

The transfer function of Fig 6 demonstrates an average acceleration transmissibility for 20mm thick foam layer to be lower than that for an 18mm thick foam layer, over a range 300Hz to 2kHz.

Referring to Fig 7 of the accompanying drawings, the same foam layers were then tested for input-output phase difference. The phase difference between input- output signals for 18mm and 20mm foam thickness foam samples was relatively low, in the range 20 to 50Hz. For applied frequencies in the range 60 to 100Hz the phase differences became significantly higher. The thicker the foam layer, the lower the frequency at which a high input-output phase difference was achieved.

A natural frequency for the layers is arbitrarily taken to be the frequency at which a phase difference between an input and output vibration is equal to 90°.

For a 20mm thick reconstituted foam layer, the natural frequency is around 6 to 8Hz lower than for an 18mm thick foam layer.

A relatively low natural frequency is beneficial for the following reasons:

Transmissibility for a single degree of freedom system is given by equation 1. T= 1 ₍₁₎ where f_f = forcing frequency; f_n = natural frequency.

A graph of transmissibility against the ratio (f_f:f_n) is illustrated in Fig 8 herewith.

It can be seen from equation 1 and Fig 8 that when the forcing frequency (f_f) is equal to the natural frequency (f , transmissibility goes to infinity although in real situations this does not occur because of damping present. When transmissibility falls below 1 then there is an element of isolation in the floor component. A perfect isolator would show transmissibility equal to zero. From Fig 8 it can be seen that as the ratio (f_f:f_n) increases above a value of 1 then transmissibility falls and thus isolation increases. For good vibration isolation therefore one usually looks for a floor construction or floor component with a natural frequency as low as possible.

Further modifications and improvements may be incorporated without departing from the scope or spirit of the invention herein intended.

Claims

rauns

1 A floor component comprising an elongate strip of foam material characterised in that said foam material comprises a plurality of open cell foam particles and a plurality of closed cell foam particles.

2 A floor component as claimed in Claim 1 wherein said open cell foam particles and said closed cell foam particles are mixed together in substantially random orientation.

3 A floor component as claimed in either Claim 1 or Claim 2 wherein said foam particles are mixed together to give a composition of 10% to 90% by volume of said open cell foam particles and 10% to 90% by volume of said closed cell foam particles.

4 A floor component as claimed in any one of the preceding Claims wherein said open cell foam particles and said closed cell foam particles are bonded together.

5 A floor component as claimed in any one of the preceding Claims wherein said foam material has a density in the range 50 to 120kgm"³.

6 A floor component as claimed in any one of the preceding Claims wherein said foam material is of thickness in the range 10mm to 30mm.

7 A floor component as claimed in any one of the preceding Claims wherein there is provided attachment means for attaching said component to a flooring joist. 8 A floor component as claimed in any one of the preceding Claims wherein an elongate rigid strip is bonded to said foam material.

9 A floor component as claimed in Claim 8 wherein said rigid strip is a timber or plywood strip.

10 A floor component as claimed in either Claim 8 or Claim 9 wherein said rigid strip is of thickness less than the thickness of a conventional floor board.

11 A floor component as claimed in Claim 8, 9 or 10 as appendant on Claim 7 wherein said attachment means is a sheet of material bonded between said rigid strip and said foam material and extending laterally to both sides of said foam material.

12 A floor component as claimed in any one of Claims 1 to 7 wherein an elongate batten is provided on one side of said foam material.

13 A floor component as claimed in Claim 12 wherein said foam material is adhered to one face of said batten.

14 A floor construction comprising:

a plurality of floor boards on said flooring components,

15 A floor construction as claimed in Claim 14 wherein said open cell foam particles and said closed cell foam particles are mixed together in substantially random orientation.

16 A floor construction as claimed in Claims 14 or 15 wherein said floor components are adapted for attachment to a respective flooring joist.

17 A floor construction as claimed in Claim 16 wherein said floor components are glued, nailed or screwed to the respective joist.

18 A floor construction as claimed in Claims 16 or 17 wherein said floor components are positioned between said joists and said floor boards and each said floor component is attachable to respective joist by a flexible web.

19 A floor construction as claimed in Claim 18 wherein said web extends either side of said joist for attachment thereto.

20 A floor construction as claimed in Claims 18 or 19 wherein said web extends between said foam material and said joist.

21 A floor construction as claimed in Claim 14 or Claim 15 wherein said floor components each have an elongate batten on one side of said foam material.

22 A floor construction as claimed in Claim 21 wherein foam material is adhered to one face of the batten .

23 A floor construction as claimed in any one of Claims 14 to 22 wherein said floor components are laid directly onto an existing floor surface without the need for attachment and the floor boards laid onto the floor components.

24 A floor construction as claimed in any one of Claims 14 to 23 wherein said floor components are laid such that the foam material is presented upwardly.

25 A floor construction as claimed in any one of Claims 14 to 24 wherein said floor boards are adhered to one or more of said floor components.

26 A floor construction comprising a plurality of floor components as claimed in any of Claims 1 to 13 and a floor deck on said floor components.

27 A floor component as hereinbefore described with reference to the accompanying drawings.

28 A floor construction as hereinbefore described with reference to the accompanying drawings.