AU678649B2 - A dry wall construction system - Google Patents

Description

L L_ 43438 HKS:MH P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

S Name of Applicant: COOL OR COSY LIMITED 4 GABRIELE IEZZI ANTONIO IEZZI Address for Service: s* COLLISON CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: A DRY WALL CONSTRUCTION SYSTEM Details of Associated Provisional Applications: PM3388 dated 17th January 1994 The following statement is a full description of this invention, including the best method of performing it known to us: I I g _I 1 ~e~b~ The present invention relates to a wall construction and to a method of wall construction.

In particular the present invention relates to a wall construction which imparts fire retardant properties to the wall so constructed.

It is desirable that walls constructed in any building should have at least some capacity to retard the progress of a fire. It is also desirable that any wall should be constructed of materials that are readily available at an economically attractive price and which are easy to handle making a wall simple to construct. A further desirable quality for any wall construction is adequate 1 0 sound absorption and minimal sound transmission.

Known prior art techniques for producing walls with fire retardant qualities have involved the use of materials which are relatively dense and result in a physical barrier to the passage of a fire.

It is also known to form insulating batt products from cellulose materials.

1 5 Typically the cellulose is formed at a remote site into a standard batt size. At the site of installation the batts are cut to the desired size and then inserted *o into a cavity formed between two wall surfaces or into a roof space. As will be appreciated such a technique is a very cumbersome and time consuming operation, and, moreover, one which does not always result in an efficiently 2 0 installed insulation product. For example, where spaces have an awkward shape or are difficult to approach it is likely that a cut and fit installation technique will not produce an optimum result and is also wasteful of material.

Also, the physical nature of the cellulose material is such that when cut the material tends to fragment thereby losing physical integrity and becoming 2 5 difficult to use.

This difficulty has been addressed by the development of systems in which moulds of differing shapes are used to create batts of differing shapes. The practical disadvantage of such a system is manifest. It requires any installer to make or hold as stock a large amount of batts and at best can only cater for 3 0 the more commonly encountered shapes.

Further techniques also involve spraying an expandable foam product into a preformed cavity. Whilst this technique is useable on existing structures it does not lend itself to the installation of insulator products in either a more open space such as a roof space or in buildings to be constructed.

It is an object of the present invention to provide a wall construction which utilises relatively economical and light weight materials without sacrificing any of the necessary qualities of fire retardency, sound absorption or economy.

In accordance with one aspect of the present invention there is provided a method of forming a wall construction comprising the steps of, erecting a first 1 0 wall side, the first wall side having inner and outer surfaces, spraying onto the inner surface of the first wall side a thermally insulating, fire retardant filler material, the filler material comprising a loose cellulose material bound in a settable liquid matrix with a liquid glue, erecting a second wall side opposed to the firs wall side to thereby 1 5 enclose the filler material between the first and second wall sides.

In preference, the cellulose fibre and glue additionally is treated with a material selected from the group consisting of borax, sodium borate, boracic acid, sodium sulphate and alum.

In preference the glue is water, PVA glue or an acrylic based glue.

oO.o 20 In preference the filler material is allowed to air before the second wall side is erected.

It has also been found to be preferable to have the loose cellulosic material to have a wet density of 2 to 5 times the dry density, as measured after the drying step.

In preference, the wall sides may be formed by either steel or timber in accordance with common building practice.

j i The board panels from which the outer skin is constructed may comprise of commonly available panels such as gyprock (trade mark) or other plaster board, fibre board or cement fibre panels.

By utilising the cellulose fibre as the filler material, the board construction on the present invention is able to be constructed cheaply and to avoid any of the environmental disadvantages associated with other filler materials such as polyurethane materials.

As will readily be appreciated by the skilled addressee, the thickness of any wall constructed in accordance would necessarily be dictated by the 1 0 performance characteristic required by the wall. For example, a wall construction in accordance with one embodiment of the present invention would typically comprise a steel stud partition lined on both sides with a single layer of 13 mm thick fire grade plaster board, the wall cavity being filled with sprayed cellulose fibre. The plaster board panels are fixed to both sides of the 15 steel studs typically with Tek screws. The plaster board joints are preferably vertically staggered. Both the plaster board joints and the screw heads are typically finished by caulking with plaster base setting compound. The cavity would typically be 75 mm thick, giving the finished wall a thickness of approximately 90 mm.

2 0 The fibre will preferably be allowed to cure before the construction is complete. A typical curing time for a wall construction with a fibre thickness of mm is 14 days.

The following non-limiting example illustrates the fire retardant properties of a wall constructed in accordance with the present invention.

2 5 The test wall comprised a steel stud partition lined on both sides with a single layer of 13 mm fire grade plaster board. The cavity between the boards being filled with sprayed cellulose fibre. The cellulose fibre had a work density of 120 kg per metre cubed and a dry density of 41.6 kg per metre cubed. The fibre was allowed to cure for 14 days before the test was commenced.

3 0 The panels were attached to the stud as described above and finished as described above. The dimensions of the partition used for the test were 3020 mm high x 3020 mm wide x 90 mm thick.

The test was conducted in accordance with Australian Standard 1530, Methods for fire tests and building materials, components and structures, part 4-1990 fire resistance test of elements of building construction.

A natural gas furnace was placed on one side of the partition. The temperature of the furnace, the unexposed face of the partition, the temperature over the joints and the deflection of the specimen were measured during the test. The test was run for 90 minutes.

The figures give details of the results of the test.

1 0 FIG 1 indicates the furnace temperature throughout the test, FIG 2 indicates the temperature on the unexposed face of the partition, FIG 3 indicates the temperature of the joints of the partition, and FIG 4 indicates the deflection at the centre of the partition.

1 5 In FIG 1 there is illustrated the variation in furnace temperature shown on the y axis in OC as measured over the time of the test as shown on the x axis and indicated in minutes. On the graph the maximum average (A) and standard temperatures are shown. As can be seen the furnace temperatures rises steadily is approximately 1000oc after 100 minutes.

ego• FIG 2 illustrates the temperature on the unexposed face of a panel throughout the test. The x and y axes are time (minutes) and temperature (OC) as for FIG 1. The lines on the graph indicate the maximum and average (A) measured temperatures. FIG 3 illustrates the temperature measurements over the joints between the panels. As can be seen, the temperature rise in this area is marginally faster than for the unexposed face.

FIG 4 illustrates a further feature of the test, namely the deflection of the panel as measured in mm over the duration of the test. Clearly the time taken for any structure to deflect is a measure of the ability of that structure to r 6 withstand the effects of the fire. As can be seen the structure maintains significant structural integrity over the first 70 to 80 minutes of the test only undergoing major deformation at approximately 85 to 90 minutes.

The following observations were made during the fire resistance test.

5 minutes There is a distinct smell of burning plasterboard.

12 minutes Visible inward deflection at the centre of the specimen. Steam is being vented from the lower left hand corner.

17 minutes Inward deflection is irregular across the face of the 1 0 specimen, localised mainly to the central area.

minutes The inward deflection has evened out to a concave shape across the specimen.

34 minutes The exposed plasterboard is developing cracks.

52 minutes Further inward deflection.

1 5 65 minutes Steam and smoke are being issued from cracks around the perimeter of the specimen. The exposed sheeting is continuing to crack.

70 minutes Screw heads are showing through stopping.

73 minutes Sections of exposed plasterboard have fallen from the right hand edge of the exposed face.

74 minutes The insulating material from behind the openings in the exposed plasterboard is falling out.

78 minutes Scorch marks are appearing along the lines of the studs on the unexposed face.

e~ 81 minutes 83 minutes Integrity loss through a screw hole opened by the movement of a stud. Spare is applied to the area adjacent to the hole.

Flaming of a duration longer than 10 seconds is occurring along scorch marks associated with a stud and at a point above the centre point of the specimen.

The sheet joints are opening on the unexposed face, the furnace burners are clearly visible, the boards are visibly shaking.

87 minutes o .t S As can be seen from the figures the partition was found to have no failure in structural adequacy at 90 minutes. The specimen was also found to have insulation properties to 82 minutes throughout the test.

Accordingly it may be concluded from the tests that the wall construction in 1 5 accordance with the present invention has a fire resistance level of 90/60/60 for the purpose of building regulations in Australia.

The sound transmission loss through a wall constructed in accordance with the present invention has also been tested and has been found to be adequate.

2 0 The sound transmission test was conducted on a wall of similar dimensions to the fire retardency test. The test was conducted in a sound reverberation room constructed in accordance with Australian Standards AS1191 and AS1045.

The rooms used in the testing also contained panels constructed and suspended in accordance with International Standards Organisation Document No 354.

The sound transmission over a range of frequencies was determined.

Figure 5 gives details of transmission loss (TL) on the y axis against frequency H3 for a range of frequency values. The panel was found to have a sound transmission loss rating of STC51, as determined by AS1191 and AS1276.

S S In conclusion it is clear that a wall construction in accordance with the present invention imparts significant fire retardant qualities to the wall together with minimal sound transmission.

Throughout this specification various indications are given as to the scope of the invention, however, the invention is not limited to any one of these but may reside in two or more combined together. The examples are given for illustration only and not for limitation.

*se

S

o*o i BI II

Claims (7)

1. A method of forming a wall construction comprising the steps of, erecting a first wall side, the first walt side having inner and outer surfaces, spraying onto the inner surface of the first wall side a thermally insulating, fire retardant filler material, the filler material comprising a loose cellulose material bound in a settable liquid matrix with a liquid glue, erecting a second wall side opposed to the first wall side to thereby enclose the filler material between the first and second wall sides.

2. A method of forming a wall construction according to claim 1, in which 1 0 the filler material is allowed to cure in a drying step before the second wall side is erected. •a

3. A method of forming a wall construction according to claim 1 or claim 2, wherein the loose cellulose material is treated with a fire retardant material comprising borax, boracic acid and salts thereof, sodium sulphate or alum or a 1 5 combination thereof.

4. A method of forming a wall construction according to any one of the preceding claims, wherein the looses cellulosic material has a wet density of 2 to 5 times the dry density, as measured after the drying step.

5. A method of wall construction according to any one of the preceding claims wherein the glue is water, PVA glue or an acrylic based glue.

6. A wall construction wherein the wall is constructed according to the method of any one of the preceding claims.

7. A method of wall construction substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings. Dated this 16th day of January 1995 COOL OR COSY LIMITED By their Patent Attorneys, 3 0 COLLISON CO. I -s ABSTRACT A method of forming a wall construction comprising the steps of, erecting a first wall side, the first wall side having inner and outer surfaces, spraying onto the inner surface of the first wall side a thermally insulating, fire retardant filler material, the filler material comprising a loose cellulose material bound in a settable liquid matrix with a liquid glue, erecting a second wall side opposed to the first wall side to thereby enclose the filler material between the first and second wall sides. 0 00 0 S OS 0* 0 se** 06 00 II