GB2541918B

GB2541918B - Non-combustible low emissivity composite board

Info

Publication number: GB2541918B
Application number: GB1515673.0A
Authority: GB
Inventors: Smith Wayne
Original assignee: SIG PLC
Current assignee: SIG PLC
Priority date: 2015-09-04
Filing date: 2015-09-04
Publication date: 2019-10-02
Anticipated expiration: 2035-09-04
Also published as: GB201515673D0; GB2541918A

Description

Non-combustible Low Emissivity Composite Board

Field of invention

The present invention relates to a non-combustible composite board for a building and in particular, although not exclusively, to a composite board exhibiting non-combustible and thermally insulating characteristics.

Background art

Wall boarding is used widely in construction both internally and externally of buildings.

Due to the different environments, the composite materials for internal and external boards typically differ with external boards further configured for water resistance including water uptake and absorption.

Externally mounted sheathing structures have emerged as an efficient approach to shield the external surface of a building from UV radiation and water to both protect the building external structure and to facilitate control of the external environment immediately surrounding the building that in turn facilitates control of the thermal performance of the building interior. A variety of external rainscreen cladding systems have been proposed in which flat external panels are mounted on an external frame or rail system that is attached to the building exterior structure via intermediate sub-frames and/or cladding boards. Example exterior cladding arrangements are described in WO 2014/204590; CA 2820970 and US 2014/0311064. The cladding boards used in such systems provide a substrate on which to mount the panel rails and sub-frame assemblies in addition to supporting or defining thermally insulating layers or regions that include fibre or foam based insulating materials and air gaps. However, there is a general trend and desire to increase the environmental and health and safety performance of construction materials including external construction boards that contribute to the overall energy and environmental footprint of a building.

Summary of the Invention

It is an objective of the present invention to provide a composite board for use in building construction that exhibits a variety of characteristics to satisfy national and International building regulations specifically with regard to mechanical, fire and thermal performance. It is a specific objective to provide a composite board configured to satisfy Euroclass reaction to fire regulation BS EN 13501. It is a further specific objective to provide a board exhibiting Al (or at least class B) non-combustible performance under regulation tests EN ISO 1182 (Non-combustibility test) and/or EN ISO 1716 (Determination of the heat of combustion). In one aspect, it is an objective to provide a category A, B or C board when tested to Euroclass standard EN 12467 including in particular bending and/or flexural strength.

The objectives are achieved by providing a non-combustible composite board comprising a substrate layer formed from a plurality of constituent materials and having at least one coating layer applied to one face of the substrate with both the substrate and the coating layer specifically optimised such that the laminated board assembly as a unitary body satisfies the physical characteristics, durability, fire and thermal performance required under national, European and International regulations. Additionally, the present board is configured to contribute to achieving desired environmental, energy and safety performance demands applied to a building under national, European and International regulations.

According to a first aspect of the present invention there is provided a dual layer noncombustible composite board for a building comprising: a substrate layer formed from a plurality of constituent materials including magnesium oxide; and a foil coating layer applied to a first face of the substrate layer, the foil coating layer having an emissivity of less than 0.3; wherein a front face of the foil coating layer represents a front face of the board and a second face of the substrate layer representing a rear face of the board; wherein a thickness of the substrate layer is in a range 2 to 20 mm; and wherein a density of the substrate layer is in a range 400 kg/m3 to 1700 kg/m3.

Preferably, the non-combustible composite board is suitable for use at an exterior of a building forming part of an external weather protection or render system such as a rainscreen or an insulated render system.

Preferably, the coating layer comprises an emissivity in the range 0.01 to 0.3; less than 0.1; less than 0.08; less than 0.05 or in the range 0.01 to 0.04.

Preferably, the foil coating layer comprises any one or a combination of the following set of Ag, Au, Cu, Al, Pt.

Preferably, the constituent materials comprise any one or a combination of magnesium chloride, woodchip or perlite. Optionally, the constituent materials comprise a glass fibre mesh. Optionally, the constituent materials comprise magnesium sulphate.

Optionally, the magnesium oxide, magnesium chloride and magnesium sulphate are included at 60 to 80 vol%. Optionally, the woodchip is included at less than 15 vol%. Optionally, the perlite is included at less than 15 vol%. Optionally, the glass fibre mesh is included at less than 10 vol%.

Optionally, a thickness of the foil coating layer is less than 1 mm; less than 0.5 mm or less than 0.2 mm. Optionally, a thickness of the foil coating layer is in the range 1 mm to 0.5 pm.

Optionally, a thickness of the foil coating layer is in the range 0.5 mm to 0.01 mm. Optionally, a thickness of the substrate layer is in a range 2 to 20 mm; 4 to 18 mm or 6 to 15 mm.

Preferably, the substrate layer and the foil coating layer are laminated together.

Preferably, a density of the substrate layer is in a range 600 kg/m3 to 1500 kg/m3.

Preferably, the board is a category Al (or at least class B) compatible board according to Euroclass system of reaction to fire performance of building products EN 13501 - EN ISO 1182 and/or EN ISO 1716. Preferably, the board is rated category A, B or C when tested to BS EN 12467.

According to a second aspect of the present invention there is provided a building cladding assembly for an exterior region of a building comprising the board as claimed herein.

The present board is advantageous to provide a structural benefit to enhance the strength and/or integrity of the cladding assembly within which the board forms a component part. In particular, the board is configured to contribute to the structural strength of the sub-frame on which the board is mounted.

According to a third aspect of the present invention there is provided a building comprising a non-combustible composite board as claimed herein secured at an exterior region of the building.

The present board comprises two opposed substantially planar faces, each face having a length and width of a variety of different dimensions to suit specific applications and the requirements of external cladding systems. Optionally, the dimensions of each face may comprise a length and width of 2400 x 1200 mm; 2700 x 1200 mm; 3000 x 1200 mm. Optionally, each face may comprise a surface area defined by a length and width in the range 2000 x 1000 mm to 3500 x 1400 mm. Optionally, a total thickness of the board may be in the range 4 to 20 mm; 5 to 18 mm; 6 to 16 mm; 6 to 15 mm. Optionally, a weight of the board may be in the range 5 kg/m2 to 15 kg/m2; 8 kg/m2 to 14 kg/m2; or 9 kg/m2 to 12 kg/m2.

Preferably, the present board is configured to satisfy a variety of different building regulation standards. In particular, the present board is configured to satisfy the following standards: Surface burning characteristics EN 13501-1 (EN 1182, EN 1716); Combustibility EN 13501-1 (EN 1182, EN 1716); Coefficient of thermal conductivity EN 12667; Coefficient of thermal resistance EN 12667; Dimensional tolerances EN 12467; Apparent density EN 12467; Water permeability EN 12467; Compressive strength ASTM D2394; Flexural strength EN 12467; Category, class EN 12467; Heat/rain resistance EN 12467; Freeze/thaw resistance EN 12467; Soak/dry resistance EN 12467.

In one aspect, the board forms a component part of a building cladding assembly for mounting at an exterior region of a building. In a further aspect, the board may form part of a floor or decking assembly at a building interior or exterior. The present board is suitable to mount and support carpet, tiles or other flooring structures and is compatible for use with a base frame such as a timber frame.

Preferably, where the board is used as a structural flooring or decking component, the board comprises a total thickness of up to 30 mm.

Optionally, the board when implemented as a floor or decking component may comprise a non-profiled or profiled perimeter edge region. Optionally, the profiled edge may comprise a tongue and groove arrangement provided at different respective edges so as to allow adjacent boards to interlock in a planar configuration.

Brief description of drawings A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

Figure 1 is a schematic view of a low emissivity, non-combustible dual layer composite board according to a specific implementation of the present invention;

Figure 2 is a schematic cross sectional side view of the board of figure 1 forming a component part within a building cladding assembly representing an external wall of a building according to one specific implementation;

Figure 3 is a further schematic cross sectional view of the board of figure 1 forming part of a building cladding assembly that includes a sub-frame according to a further specific implementation;

Figure 4 is a perspective view of the board of figure 1 forming a component part within an insulated render system according to one specific implementation.

Detailed description of preferred embodiment of the invention

The present board is suitable for a variety of different architectural applications and constructional uses associated with a building including in particular the cladding of an exterior of a building. In particular, the present board is suitable for wall finishing applications including use as a component part within insulated render systems, rainscreen systems, timber and metal cladding arrangements and general sheathing, cladding and screening structures that represent the external walls of a building. Other applications include use as a flooring system, floor covering or wall component either internally or externally. The board according to the subject invention exhibits high performance with regard to non-combustible and low emissivity criteria in addition to satisfying desired physical criteria such as strength, flexibility and durability according to various national, European and International standards. In particular, the present board is configured to be Al (or at least class B) non-combustible under EN 13501 and in particular EN ISO 1182 and/or EN ISO 1716. The present board is also configured as a category A, B or C structure when tested to EN 12467.

Referring to figure 1, a non-combustible board 106 comprises a substrate layer indicated generally by reference 100 and a coating layer indicated generally by reference 101 coupled together to form a laminate structure. Substrate layer 100 comprises a first face 102 and a second face 103. Coating layer 101 is laminated onto first face 102 such that a rear face 104 of coating layer 101 is non-detachably bonded to the substrate first face 102 to form a dual-layer assembly. Accordingly, a front face 105 of coating layer 101 is exposed to represent a front face of the composite board 106 with the second face 103 of substrate layer 100 representing a rear face of board 106.

According to the specific implementation, substrate layer 100 comprises a thickness greater than a corresponding thickness of coating layer 101. In particular, coating layer 101 is formed as a foil and comprises a thickness in the range 0.5% to 2% of a thickness of substrate layer 100. According to the specific implementation, substrate layer 100 comprises a thickness in a range 6 mm to 15 mm and the coating layer 101 comprises a thickness of less than 1 mm.

Referring to figure 2, an external rainscreen cladding system is configured as an external wall structure of a building. The building interior is defined by an acoustic plaster board 301 that represents and inner leaf of the system having a rear face 303 that is internal facing within the building. Timber studs (beams) 312 are, in turn, mounted to an external face 302 of plaster board 301. The present board 106 is secured to timber studs 312 via board rear face 103. A plurality of mounting brackets 215 are secured directly to board front face 105 (defined by coating layer 101). Each bracket 215 comprises a thermal insulation layer (or pad) 217 non-detachably mounted at a foot 218. A neck 219 extends generally perpendicular from foot 218 and a head 216 is provided at an opposite end of neck 219 relative to foot 218. Foot 218 comprises a generally planar body with insulating layer 217 mounted at a rear face of foot 218 via an adhesive such as an epoxy resin. Pad 217 comprises a material having a thermal conductivity of 0.016 to 0.018 W/(m K) (at a mean temperature of 23.9 °C and as measured as a compressive load of 13.79 kPa). In a preferred embodiment, pad 217 comprises Cryogel available from Aspen Aerogels, Inc., NA 05132, USA. Pad 217 comprises a thickness in a plane perpendicular to face 103 of 5 mm to 10 mm incorporating the silica aerogel material and a flexible fibre coating provided at a front face and a rear face of the pad 217.

Bracket 215 is secured to board 106 via attachment bolts 200 extending through foot 218 and having bolt heads 201 positioned against the front face of foot 218. Bracket head 216 is secured to a tail member 206 that forms a rearward part of panel mounting rail assembly 205. In particular, tail member 206 is formed as elongate plate at least partially received within a mouth defined by a pair of fingers or plates provided at head 216 so as to be gripped by frictional contact to securely mount rail 205 at bracket 215. Accordingly, tail member 206 is aligned generally parallel with bracket head 216 and neck 219 so as to extend generally perpendicular to foot 218, insulation pad 217 and board 106. A rail head 207 also extends perpendicular to tail member 206. Rail head 207 comprises a mount face 214 for positioning in contact and attachment to a rear face 209 of a plurality of cladding panels 208. Each panel 208 comprises an external face 210 that represents an extemalmost part of the cladding assembly. Due to the respective lengths of bracket neck 219, head 216 and tail member 206, a spatial gap 202 is created between board 106 and cladding panels 208. According to a further embodiment, a sheet insulation material may be positioned in the gap region 202 between board front face 105 and external cladding panel rear face 209 to enhance the thermal partitioning of the external cladding panels 208 and plaster board 301.

Coating layer 101 comprises a generally reflective material having an emissivity of the order of 0.03. Accordingly, with board 106 orientated according to figure 2 (with the reflective layer 101 being external facing), the external cladding assembly is configured to control the climate of the interior of the building by reflecting radiation away from covering board 301. This configuration is advantageous for a building in a generally hot climate. According to further implementations, board 106 may be positioned in the opposite orientation with the reflective layer 101 facing board 301 so as to retain thermal radiation within the building interior. Such a configuration is advantageous in cool climates.

Figure 3 illustrates a further embodiment of an external cladding system comprising a steel framing system (SFS) cladding arrangement. As with the embodiment of figure 2, plaster board 301 (alternatively termed ‘cover board’) represents an inner leaf of the structure defining the building interior. Board 301 may optionally comprise a vapour control external layer (not shown) provided at external facing face 302. According to further embodiments, a plurality of boards 301 may be positioned at the internal facing region of the system. A sub-frame assembly is then mounted at board face 302 with the sub-frame assembly comprising a plurality of lightweight steel frame support members 300 attached directly to board face 302. Composite board 106 is mounted at an opposite side of support members 300 via contact with front face 105. Accordingly, a spatial gap 304 is created between board front face 105 and cover board face 302. A plurality of brackets 215 are then attached to board rear face 103 via contact with insulation pad 217. Accordingly, a plurality of the composite boards 106 are positioned intermediate brackets 215 and steel frame support members 300 and are advantageous to enhance the strength of the cladding assembly. The cladding panels 208 are mounted at the brackets 215 via the rail assembly 205 as described with reference to figure 2. Brackets 215 are secured to board rear face 103 via the same bolts 200 as described with reference to figure 2. According to further embodiments, bolts 200 may be configured to extend fully through boards 106 and into the respective steel frame support members 300. As will be appreciated, frame support members 300 may be attached to board 106 via respective attachment bolts, screws, pins, plugs, clips and the like. As with the embodiment of figure 2, should it be required to enhance the thermal isolation between external cladding panels 208 and cover board 301, a first layer of insulation material (not shown) may be positioned within gap region 202 and layered onto board rear face 103. Additionally, a second layer of insulation material (not shown) may be positioned within gap region 304 in contact between board front face 105 and/or cover board face 302.

Referring to figure 4, board 106 is included within an insulated render system positioned at an exterior region of a building wall structure. An inner leaf of the system (that defines the building interior space) comprises plaster board 301 having rear face 303 (being internal facing within the building) and a front face 302 (being external facing). A timber stud frame comprises timber beams 306 each having a front face 308 and a rear face 307 that is secured against plaster board front face 302. The rear face 105 of the present non-combustible board 106 is secured against timber beam front faces 308. A suitable insulation material 312 is sandwiched between plaster board 301 and composite board 106. Accordingly, board 106 represents a sheathing board within the render system and mounts a plurality of rails 309 via outward facing second face 103. Rails 309 support an externally positioned substrate 310 and external render layer 311.

According to a further specific implementation, the present board may be used at a building interior as a wall or floor/decking component. When employed as a floor or decking component, the board may comprise a total thickness of up to 30 mm and in particular 20 to 30 mm. To facilitate ease of mounting and increase the structural integrity of the resulting structure, the board may comprise a profiled perimeter edge to create an interlocking assembly. The profiled edge may comprise tongue and groove, stepped or other profiled interlocking/overlapping extensions or abutments at some or all of the perimeter edges of the board.

The present composite board 106 is advantageous to enhance the thermal isolation between board 301 and external cladding panels 208. This is achieved, in part, by the constituent materials of substrate layer 100. The reflective, low-emissivity coating layer 101 is configured to inhibit the transmission of thermal radiation either into or from board 301 dependent upon the orientation of board 106 (and in particular layers 101,100) relative to the internal facing board 301.

Substrate layer 100 comprises a plurality of constituents configured to optimise the various physical and mechanical characteristics of the board 106 in addition to satisfying various performance criteria including in particular water/vapour permeability and resistance; compressive strength; flexural strength and weight according to performance standard EN 12467. The constituent materials are also configured for heat/rain, freeze/thaw and soak/dry resistance under durability performance criteria EN 12467. The constituent materials of substrate layer 100 are also selected such that board 106 satisfies reaction to fire performance standards including in particular surface burning and non-combustibility performance characteristics according to standard EN 13501 and in particular tests EN ISO 1182 and/or EN ISO 1716. Additionally, the constituent materials of substrate layer 100 and coating layer 101 are selected such that board 106 is configured to satisfy thermal conductivity and resistance performance according to International standard EN 12667. In particular, the board 106 may comprises a k-value of 0.19 W/(m.K_1) and an r-value of 0.039 W/m2K.

The above physical, durability, fire and thermal performance criteria are provided, in part, as substrate layer 100 comprises magnesium oxide, magnesium chloride, woodchip, perlite and/or glass fibre mesh. The substrate layer 100 may also comprise magnesium sulphate. In particular, the board comprises MgO, MgCl and MgSCU at 60 to 80 vol%. The woodchip may be included at less than 10 vol%, the perlite included at less than 10 vol% and the glass fibre mesh included at less than 5 vol%. The reflective coating layer 101 to provide the desired emissivity may comprise aluminium or an aluminium derivative. In some embodiments, the low emissivity layer 101 comprises any one of the group consisting of Ag, Au, Cu, Al or Pt. Coating layer 101 may alternatively comprise an ion-doped metal oxide including any one or a combination of indium tin oxide, fluorine-doped tin oxide, aluminium-doped zinc oxide, gallium zinc oxide and the like.

The low emissivity layer comprises an emissivity in the range 0.01 to 0.3 and specifically 0.01 to 0.05. Where the coating layer 101 comprises aluminium, the emissivity comprises 0.03.

Example 1 A low emissivity laminate board comprises a substrate layer comprising by volume MgO, MgCl, MgSO4 at 70%; woodchip at 5 to 10%; perlite at 5 to 10% and glass fibre mesh at 2 to 5% with the remainder comprising any one or a combination of these constituents. Substrate layer is manufactured to a thickness of 10 to 12 mm. A coating layer is laminated onto the substrate layer. The coating layer comprises aluminium foil of 0.025 mm, laminated via an adhesive according to conventional lamination techniques.

The dual layer board of example 1 is categorised as Al (or at least class B) noncombustible via performance standard EN 13501 and in particular tests EN ISO 1182 and EN ISO 1716. EN ISO 1182 identifies products that will not, or not significantly, contribute to a fire, regardless of their end use. EN ISO 1716 determines the potential maximum total heat release of a product when completely burning, regardless of its end use. The board of example 1 is also categorised as A, B or C when tested under EN 12467 including in particular bending strength under EN 310; 1993.

Performance Results A board according to example 1 was tested in accordance with standard UNE-EN 13501-1:2007 +A1:2010. The density of the board was documented as 945kg/m3. The results of the performance test are detailed in table 1.

Table 1 - test results for board of example 1 under EN ISO 1716:2011 and ΕΝ 1182:2010

Claims

1. A dual-layer non-combustible composite board for a building comprising: a substrate layer formed from a plurality of constituent materials including magnesium oxide; and a foil coating layer applied to a first face of the substrate layer, the foil coating layer having an emissivity of less than 0.3; wherein a front face of the foil coating layer represents a front face of the board and a second face of the substrate layer representing a rear face of the board; wherein a thickness of the substrate layer is in a range 2 to 20 mm; and wherein a density of the substrate layer is in a range 400 kg/m3 to 1700 kg/m3.

2. The board as claimed in claim 1 wherein the emissivity is in the range 0.01 to 0.

3. 3. The board as claimed in claim 1 wherein the emissivity is less than 0.1.

4. The board as claimed in claim 1 wherein the emissivity is less than 0.08.

5. The board as claimed in claim 1 wherein the emissivity is in the range 0.01 to 0.05.

6. The board as claimed in any preceding claim wherein the foil coating layer comprises any one or a combination of the following set of Ag, Au, Cu, Al, Pt.

7. The board as claimed in any preceding claim wherein the constituent materials comprise any one or a combination of MgCl, woodchip or perlite.

8. The board as claimed in claim 7 wherein the constituent materials comprise a glass fibre mesh.

9. The board as claimed in claims 7 or 8 wherein the constituent materials comprise magnesium sulphate.

10. The board as claimed in claim 9 wherein the magnesium oxide, MgCl and magnesium sulphate are included at 60 to 80 vol%; the woodchip is included at less than 15 vol%; the perlite is included at less than 15 vol%; and the glass fibre mesh is included at less than 10 vol%.

11. The board as claimed in any preceding claim wherein a thickness of the foil coating layer is less than 1 mm.

12. The board as claimed in any preceding claim wherein a thickness of the substrate layer is in a range 4 to 18 mm.

13. The board as claimed in any preceding claim wherein the substrate layer and the foil coating layer are laminated together.

14. A building cladding assembly for an exterior region of a building comprising the board as claimed in any preceding claim.

15. A flooring assembly for an exterior or interior of a building comprising the board as claimed in any one of claims 1 to 13.

16. The assembly as claimed in claim 15 wherein the board comprises a total thickness of up to 30 mm.