AU2005202329B2

AU2005202329B2 - Wall system

Info

Publication number: AU2005202329B2
Application number: AU2005202329A
Authority: AU
Inventors: Christopher Lee Healy; John Philip Mclanders
Original assignee: Stramit Corp Pty Ltd
Current assignee: Stramit Corp Pty Ltd
Priority date: 2004-05-28
Filing date: 2005-05-27
Publication date: 2010-03-25
Anticipated expiration: 2025-05-27
Also published as: AU2005202329A1

Description

rwyudL1un a.4 AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT. Invention Title: WALL SYSTEM Applicant: STRAMIT CORPORATION PTY LIMITED The following statement is a full description of this invention, including the best method of performing it known to me: 1 2 WALL SYSTEM This invention relates to a fire rated exterior wall system. One form of fire rated exterior wall system utilises gypsum plasterboard facing 5 over a metal frame to achieve a fire rating. In these systems, the facing is made up by multiple layers. Each layer comprises an edge-to-edge array of separate gypsum plasterboard sheets. The multiple layers are necessitated by the need for a sufficient thickness for a given fire rating, and the need for the sheets of one layer to cover gaps between adjacent sheets of a next layer. For the latter reason, the sheets of a 10 layer are off-set with respect to those of the next layer. This is to minimise the risk of flame being able to penetrate gaps between adjacent sheets. If these gaps are penetrated, the flame can access the edges of the cardboard facing of the gypsum plasterboard sheets, and more readily cause a fire to spread by combustion of a cardboard facing of the plasterboard. 15 The multiple layers may be provided by use of at least two layers of gypsum plasterboard. Alternatively, they can be provided by at least one layer of gypsum plasterboard in combination with another type of board, such as those sold under the trade marks "Villaboard" and "Hardiflex". In each case, successive layers providing the facing are in face-to-face contact. This results from a first layer being fastened to ?0 a wall frame and the or each other layer being fastened to the preceding layer. That one form of fire rated exterior wall system performs satisfactorily. However, there are a number of disadvantages which result from need for multiple layers. The need for gaps to be protected requires some care when fastening successive layers of sheets. Care also is appropriate when fastening the sheets of a 25 layer in order to minimise the width of any gaps. Additionally, the multiple layers necessitate a relatively high material cost, as well as a relatively high labour cost in fastening the layers. The present invention is directed to an alternative system, and to a method for its construction, each of which at least in preferred forms of the invention enable one 30 or more of the above problems to be at least reduced. The present invention provides a fire rated exterior wall system which has a frame and, disposed over and covering the exterior side of the frame, a 'file =ne 3 facing including a close fitting array of sheets, wherein the sheets are made of calcium silicate. The wall system of the present invention is provided with external cladding spaced from the facing, which includes profiled metal sheeting. The frame is most desirably a metal frame including columns, such as of I 5 section or other suitable section, with successive columns bridged by vertically spaced girts (purlins). In such case, the facing is built up by the calcium silicate sheets being fixed to exterior faces of the purlins. For a given thickness, calcium silicate sheets comprising the facing have a superior fire rated performance than gypsum plasterboard sheets. Also, calcium 10 silicate sheets are economical and strong, particularly when compared on the basis of respective thickness requirements for a given fire rating. Thus, for a given fire rated life (FRL) of, for example, 30, 60 or 90 minutes, a substantially lesser thickness is required for calcium silicate sheets compared with gypsum plasterboard sheets. A number of significant further advantages are obtained with use of calcium 15 silicate sheets. They do not require a cardboard facing. They therefore do not present a risk of being breached by a fire due to combustion of a facing. It consequently is not necessary to have sheets in two or more offset layers to ensure coverage of any gap between adjacent sheets of a layer. That is, the wall system of the present invention is able to have a facing including a single layer of calcium 20 silicate sheets, with the thickness of the sheets able to be chosen to achieve a required fire rating. Moreover, subject to the gaps between adjacent calcium silicate sheets of the single layer not being too great, the presence of gaps can be tolerated. However, it is highly preferred that the gaps are not greater than about 2mm between horizontally successive sheets. 25 In the system based on gypsum plasterboard, the fire rating necessitates a vapour permeable membrane being provided between the plasterboard facing and the external cladding. The membrane may, for example, be stapled to the facing. After this battens are fixed through the plasterboard to the girts behind the plasterboard, and the cladding then is fixed to the battens. For the same fire rating, 30 the wall system of the invention does not necessitate use of a vapour permeable membrane. Also, with the system based in plasterboard, the battens are required to be relatively <filename> 4 deep, so as to result in a sufficiently wide insulting air gap between the gypsum plasterboard facing and the cladding. The system of the present invention, in addition to not requiring a vapour permeable membrane, is able to achieve the same fire rating with a narrower insulating air gap between the calcium silicate 5 facing and the cladding. The system of the present invention can use similar girts and battens to those used in the system utilising gypsum plasterboard. The invention preferably utilised C or Z girts, while it can use top hat or Z battens. However, the invention preferably utilises battens of U-shaped cross-section. These are installed with the 10 free-edge of each side flange bearing against the calcium-silicate facing. However, each side flange preferably has an inturned margin so that the free edges are rounded, thereby minimising risk of injury to an installer or damage to the calcium silicate facing. In a method according to the present invention, the frame is erected, the 15 girts are fixed to the frame at a required vertical spacing therebetween, and the facing of calcium silicate sheets is secured to the girts. Battens then are positioned against the facing, after which cladding is secured through the facing to the girts. With use of battens of the preferred U-shaped cross-section, further benefits are able to be achieved. 20 The preferred U-shaped battens engage the facing along the free edge of each of its side flanges. The battens therefore are not prone to tilting and it therefore is not necessary that they initially be fixed against the facing by fasteners. Rather, each batten can be held in position by means of strips of adhesive tape which extend across the batten at spaced intervals along its length 25 to hold the batten against the facing. The battens then can be more securely fixed in position when fixing the cladding, through the facing, to the girts. For this, at least some fasteners for the cladding can penetrate through the battens. However, it is not necessary that all fasteners penetrate the battens. Indeed, provided at least some fasteners pass just below a batten, loss of grip by the 30 adhesive tape will not result in the batten dropping, as it will be supported from below by those fasteners. In order that the invention may be understood more readily, the following description is directed to the accompanying drawings, in which: W:\Sandra\RNC WORK\2005\Patents 2005\IRN746025.doc 5 Figures 1 to 6 schematically show partial detail of a fire rated exterior wall system according to the present invention in successive stages of its construction; Figure 7 is an end elevation of the wall system as shown in Figure 6; Figures 8 and 9 show respective alternatives to Figure 6 for cladding 5 orientation; Figure 10 shows an end elevation of a preferred form of batten for use in the wall system; and Figure 11 shows partial detail, in a vertical sectional view, of an installed fire rated wall system having battens as in Figure 10. 10 Figure 1 shows part of the frame 10 for the fire rated exterior wall system. The frame 10 has a plurality of building frame columns 12. Only one column 12 is shown, but others are at substantially uniform intervals along the wall system. As illustrated by the one shown, the columns 12 are of I-section in this instance, but the columns can be of other forms. The lower end of each column 12 is 15 embedded in or secured to a concrete base 13 (see Figures 7 to 9). Frame 10 also includes a plurality of girts or purlins 14 which bridge and are connected to successive columns 12. The girts 14 are of Z-section in this instance, but other forms such as of C-section can be used. The girts 14 are of uniform spacing from each other, at 1200 mm in each case except for the lower 20 two where the spacing is 1000mm. This difference is due to the bottom girt 14a being 200mm above the concrete base 13. The spacing may be other than indicated but, in any event, the spacing is selected for the reason detailed below in relation to Figures 2 and 3. The girts 14 are secured to columns 12, such as by bolts. Care is taken to 25 ensure the required spacing, as well as the horizontal disposition of the girts. Usually the length of a wall will exceed the length of girts 14, in which case care is to be taken to ensure successive girt lengths are in line. Following completion of frame 10, a facing 15 is provided over the exterior of frame 10, as shown in Figures 2 and 3. The facing 15 is made up of a plurality 30 of sheets 16 made of calcium silicate provided in a single layer. Prior to installation, the sheets 16 are checked for damage and only those in good order are used. If the sheets 16 have a smoother side, this preferably faces towards frame 10. Each sheet 16 may be 1200mm by 2400mm and they are installed with their major dimension parallel to columns 12. A lowest row of sheets 16a is WASandra\RNC WORK\2005xPatents 2005\lRN746025.doc 6 installed first. Each of the sheets 16a of that row extends over the lowest three girts 14a, 14b and 14c. The sheets 16a are arranged substantially symmetrically with respect to the second lowermost girt 14b, leaving not more than a slight gap between the lower edge of each sheet 16a and the top surface of concrete base 5 13. Each sheet 16a of the lowest row is fixed through its middle to the girt 14b. This is by fasteners, such as No. 10x25 self-drilling and threading screws. As so fixed, each sheet 16a of the lowest row has its upper edge between the top and bottom edge of girt 14c. With each sheet 16a of the lowest row fixed to girt 14b, it then can be fixed 10 to girts 14a and 14c. Alternatively, the remaining rows of sheets 16b, 16c etc. may be similarly partly fixed, prior to completion of fixing of each sheet to the girts it bridges. In any event, sheets 16b first are fixed to the next girt (not shown) above girt 14c, and then similarly for sheets to comprise a third row (not shown). The gap between the bottom edge of sheets 16a and the concrete base 13 15 preferably does not exceed 5mm. Also, any gap between the sheets 16 of one row and those of the next row preferably does not exceed 5mm. Any gap between successive sheets 16 in the same row preferably does not exceed 2mm. However, while there may be gaps as indicated, these most preferably are avoided in so far as is possible, by sheets 16a resting on base 13 and by the 20 sheets 16 within a row, and also those of successive rows, firmly abutting. With the facing 15 comprising sheets 16 of calcium silicate fully installed, battens 18 then are positioned. The form of a batten 18, in end elevation, is shown in Figure 10. The batten 18 is of elongate form and has a substantially uniform U-shaped cross-section. The batten 18 thus has opposed side flanges 20 25 joined by a web 22, with the flanges 20 flaring outwardly from web 22. Also, each flange 20 has a free edge 24 which is rounded, so as not to present a safety risk to installers. The edges 24 are formed by providing a strip from which batten 18 is formed with respective inturned margins 26. Each margin 26, which may be formed by crush folding, projects towards the inner surface of web 22, at a small 30 angle such as about 50 to each side flange 20. As shown most clearly in Figures 4 and 11, a respective batten 18 is positioned across the sheets 16 of a row, in register with each girt 14. Thus, there is a batten 18 at the middle of the sheets 16 of the row. Also there is a perspective batten 18 along the upper and lower edge of the sheets 16 of the row. W:\Sandra\RNC WORK\2005\Patents 2005XIRN746025.doc 7 When positioned as required, with its edges 24 against the sheets 16, each batten is secured in place by a strip of adhesive tape 28 provided at a number of locations along the length of the batten. With facing 15 installed, edge flashing 30 then is positioned as shown in 5 Figure 5 and fixed against the lowest batten 18a located adjacent to girt 14a. The flashing 30 is fixed such as by No. 12x55mm self-drilling and threading screws. Care is taken to ensure that the flashing 30 is in contact with the concrete base 13. The screws are applied through the batten 14a, the sheet 16a and into the girt 14a. Cladding 32 then is provided over the exterior such as in accordance with 10 the arrangement shown in one of Figure 6, 8 or 9. These Figures each show the cladding 32 as comprising profiled metal sheeting, and they differ in that the ribs of cladding 32 extend vertically, horizontally or diagonally, respectively. The cladding 32 is made up of individual sheets 33, such as of profiled sheet metal. Suitable examples are Stramit Monoclad, Stramit Longspan and 15 Stramit Corrugated sheeting, although a range of other profiled sheet metal can be used. With a cladding sheet 33 positioned in the required orientation, it is valley fixed, such as by use of No. 12x55 mm self-drilling and threading screws. That is, the screws are positioned in the valley or pan between successive ribs of the sheet profile. The screws extend through the cladding sheet 33, through or closely 20 adjacent to the battens 18, and through the facing 15 into a girt 14. If a screw does not extend through a batten 18, it preferably is closely adjacent the underside of the batten. In the case of screws fixing in girt 14a, they also extend through the flashing 30. Successive cladding sheets 33 are positioned and fixed to complete 25 cladding 32. Care is to be taken in ensuring the correct overlapping by the sheets of one row relative to those of the next lower row. A minimum overlapping of about 50 mm is preferred. Also, it is desirable to ensure that screws fixing the sheets 33 of cladding 30 are not over tightened, to prevent deformation of the sheets 33. Also, the screws of course are to be in line with respective girts 14 and 30 if required, with respective battens 18. If screws do not extend through a batten 18, it is highly preferred that sufficient of them extend below and closely adjacent the batten to support it in position in the event that tape strips 28 loose their adhesive strength due to ageing. W:\Sandra\RNC WORK\2005\Patents 2005\IRN746025.doc 8 In the arrangement of Figure 8, valley fixing necessitates fasteners which extend into each successive grit 14. However, the spacing between girts is too great for this to be sufficient. To enable intervening fasteners, battens 18 are provided in relatively short lengths, with successive lengths spaced to provide 5 gaps 34 between them. Across these gaps, further battens 36 are provided. The battens 36 extend vertically, at least between the girts 14 spaced by a calcium silicate sheet 16. The battens, here shown as being of a preferred top hat form, are fixed to those girts 14, such as by No. 12x55 mm self-drilling and threading screws. The cladding sheets 33 then are positioned and secured by fasteners, 10 also such as by No. 12x55 mm screws, with the screws extending through the sheet 33, then batten 36 and then sheet 16, with some screws also extending into the girts 14. The battens 36 are shown in Figure 8 as extending centrally with respect to a sheet 16. However, other arrangements are possible. A batten 36 could bridge 15 the edges of laterally adjacent sheets 16, although this can be undesirable due to their risk of damaging the edge of one or other of the sheets. Figure 11 shows a partial sectional view through a fire rated wall system of the invention. This view is somewhat schematic . The section of cladding sheet 33 of cladding 32 is taken through a valley or pan between successive ribs. The 20 sheet 33 is shown as retained in the partial section shown by a screw 38 inserted through the valley, then batten 18, then upper one of calcium silicate sheets 16 in successive rows, and through the girt 14 behind the adjacent edges of those sheets 16. Also shown is the adhesive tape 28 by which batten 18 was held against sheets 16, prior to the insertion of screw 38. 25 Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention. WASandra\RNC WORK\2005\Patents 2005%[RN746025.doc

Claims

1. A fire rated exterior wall system including: a frame, 5 a facing disposed over and covering the exterior side of the frame including a close fitting array of sheets made of calcium silicate; and external cladding spaced from the facing which includes profiled metal sheeting. 10

2. A fire rated exterior wall system according to claim 1, wherein the frame is a metal frame including at least two columns, with successive columns bridged by vertically spaced girts.

3. A fire rated exterior wall system according to claim 2, wherein the array of 15 calcium silicate sheets are fixed to exterior faces of the girts.

4. A fire rated exterior wall system according to claim 2 or 3, wherein each girt includes a C-shaped or Z-shaped cross-sectional profile. 20

5. A fire rated exterior wall system according to any one of claims 2 to 4, wherein each column includes an I-shaped cross-sectional profile.

6. A fire rated exterior wall system according to any one of the preceding claims, wherein the facing includes a single layer of calcium silicate sheets. 25

7. A fire rated exterior wall system according to any one of the preceding claims, wherein the gaps between adjacent calcium silicate sheets are not greater than about 2mm between horizontally successive sheets. 30

8. A fire rated exterior wall system according to any preceding claim, wherein the external cladding is spaced from the facing by the provision of battens placed between the external cladding and the facing. <fdename> 10

9. A fire rated exterior wall system according to claim 8, wherein each batten includes a U-shaped cross-sectional profile, having opposed side flanges joined by a web. 5

10. A fire rated exterior wall system according to claim 9, wherein each batten is installed with the free edge of each side flange bearing against the facing.

11. A fire rated exterior wall system according to claim 9 or 10, wherein each side flange includes an in-turned margin so that the free edges are rounded. 10

12. A fire rated exterior wall system according to claim 8, wherein each batten includes a Z-shaped cross-sectional profile.

13. A method of constructing a fire rated exterior wall system, including 15 erecting a wall frame, fixing girts to the frame at a required vertical spacing therebetween, securing a facing of calcium silicate sheets to the girts, positioning battens against the facing, and securing cladding which includes profiled metal sheeting through the facing to 20 the girts.

14. A method of constructing a fire rated exterior wall system according to claim 13, wherein the battens have a U-shaped cross-sectional profile having opposed side flanges joined by a web, and the step of positioning the battens against the facing 25 includes positioning the free edge of each side flange against the facing.

15. A method of constructing a fire rated exterior wall system according to claim 13 or 14, including holding the battens in position relative to the facing by means of strips of adhesive tape extending across each batten at spaced intervals along their length 30 to hold the battens against the facing.

16. A method of constructing a fire rated exterior wall system according to any one of claims 13 to 15, including securing the cladding through the facing to the girts with fasteners. <fdmeu e 11

17. A method of constructing a fire rated exterior wall system according to claim 16, including penetrating at least some of the battens with the fasteners. 5

18. A fire rated exterior wall system according to any one of the embodiments substantially as herein described and illustrated.

19. A method of constructing a fire rated exterior wall system according to any one of the embodiments substantially as herein described and illustrated. <lenam.e>