A PASSIVE FALL PREVENTION DEVICE TECHNICAL FIELD

[0001] The present invention relates to a passive fall prevention device. More particularly, the present invention relates to a passive fall prevention device for the management of the risk of falls from height.

BACKGROUND ART

[0002] Fall prevention devices are used in roof spaces to manage the risk of falls at height and, especially, to prevent perimeter falls or internal falls through a roof. Passive fall prevention devices such as temporary work platforms (scaffolds, elevating work platforms, work boxes, purlin trolleys, and the like) and perimeter protection (screens, guardrails, barriers, safety meshes and the like) require the lowest level of skill to operate and maintain while active fall prevention devices (rope access systems, travel restraint systems, fall arrest systems, ladders, and the like) require a higher level of skill for their safe use. In particular, passive fall prevention devices such as safety meshes may provide fall protection for roof installers and offer long-term protection against falling for maintenance and repair workers.

[0003] Safety meshes and knitted nylon mesh nets may be fixed to the roof structure between the cladding and the roof structure. However, this type of passive fall prevention device may require roof spacers between the truss and purlins to achieve minimum requirements of the building code and a worker falling onto the safety mesh may trap their arm or leg in a gap in the lattice of the mesh. Additionally, a roof installer or other worker will need to separately install roof insulation material, making roof installation (or repair) a time consuming and more costly process.

[0004] Laminate materials comprising an insulating material with an integrated safety mesh or reinforcing material have also been used as fall arrest devices.

Whilst this type of passive fall prevention device may be easier to install than wire safety mesh and involves a single step installation process, the laminate materials are often based on polymers which are flammable and have high thermal conductivity. [0005] These laminate materials are provided with one or more outer reflective layers in order to improve the thermal performance of the laminate material, however the outer reflective layers (such as aluminium foil) have a high glare which may affect worker’s eyesight and cause falls. As a consequence, the laminate materials are provided with an anti-glare material to improve safety. However, these anti-glare materials generally have a low reflectivity and a consequence high emissivity which reduces the thermal resistance of the laminate material.

[0006] Thus, there would be an advantage if it were possible to provide an improved passive fall prevention device or at least one that ameliorates the aforementioned problems.

[0007] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0008] The present invention is directed to an improved passive fall prevention device, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0009] With the foregoing in view, the present invention in a first aspect, resides broadly in a passive fall prevention device comprising: at least one reflective layer; at least one thermal insulating layer, at least one reinforcing layer, and at least one photochromic layer.

[0010] The passive fall prevention device may be used for in any suitable structure. For instance, the passive fall prevention device may be used as an insulation material in residential buildings, commercial buildings, industrial buildings, other structures, either inhabited or uninhabited, or the like. In this instance, it is envisaged that the passive fall protection device may be used as an insulation material in roof spaces, walls, floors, doors, garage doors, and the like. In a preferred embodiment of the invention, the passive fall prevention device may be used in roof spaces. However, it will be understood that the passive fall prevention device may be used for any suitable purpose requiring an insulation material with impact resistance.

[0011] The passive fall prevention device may be of any suitable size, shape and configuration. However, it will be understood that the size and shape of the passive fall prevention device may vary depending on a number of factors, such as the type of structure and space in which it will be used, the environmental conditions, and the type of material used to fabricate the passive fall prevention device. For instance, the passive fall prevention device may be a prefabricated panel, may be a sheet material, or the like. The passive fall prevention device may be rigid or flexible. In some embodiments of the invention, the passive fall prevention device may be resiliently deformable. It will be understood that the passive fall prevention device may be cut to size, trimmed, and the like, as required to fit the structure. In use, it is envisaged that cut edges of the passive fall prevention device may be sealed by the roof installer or other worker in order to maintain the barrier to conductive heat, humidity, water and vapour penetration. For instance, the cut edges of the passive fall prevention device may be sealed by using an adhesive or adhesive tape, heat treatment, chemical treatment, mechanical treatment (such as ultrasonic welding, compression, and the like), or a combination thereof.

[0012] In an embodiment of the invention, the passive fall prevention device comprises at least one layer. Preferably, the passive fall prevention device may be a multi-layer structure. In an embodiment of the invention, one or more layers of the passive fall prevention device may be adhered to one or more adjacent layers. Any suitable technique may be used to adhere the one or more adjacent layers together. However, it will be understood that the type of technique may vary depending on a number of factors such as the type of materials used to fabricate the layers and the insulation and safety requirements of the passive fall prevention device.

Alternatively, one or more internal layers of the passive fall prevention device may be encapsulated by an external layer, such that the external layer maintains the one or more internal layers in position relative to one another and substantially precludes movement of the one or more internal layers. In this instance, it is envisaged that adjacent edges of the external layer may be sealed to one another to form a cavity in which the one or more internal layers may be located. The edges of the external layers may be sealed to one another by any suitable technique, such as, but not limited to, an adhesive or adhesive tape, heat treatment, chemical treatment, mechanical treatment (such as ultrasonic welding, compression, and the like), or a combination thereof. In some embodiments of the invention, the external layer may be provided in the form of a sleeve or sheath.

[0013] In an embodiment of the invention, the passive fall prevention device may comprise at least one reflective layer. In embodiments in which a plurality of reflective layers may be present, the layers may be of the same material type or may be of different types of material. Preferably, however, the reflective layers may reflect radiant heat and/or provide a barrier against water and vapour penetration.

[0014] The at least one reflective layer may be located in any suitable orientation in the passive fall prevention device. For instance, the at least one reflective layer may form an internal layer, may form an external layer, or any suitable combination thereof. In a preferred embodiment of the invention, the at least one reflective layer may form an external layer of the passive fall prevention device. Thus, in this embodiment of the invention, the reflective layer forms an outer facing of the passive fall prevention device. In an embodiment of the invention, the passive fall prevention device may be provided with an upper reflective layer and a lower reflective layer, such that the upper reflective layer and the lower reflective layer form external layers of the passive fall prevention device and wherein the at least one thermal insulating layer and the at least one reinforcing layer may be substantially encapsulated therein. In some embodiments of the invention, one or both of the upper reflective layer and the lower reflective layer may be provided with at least one photochromic layer. In some embodiments of the invention, the at least one photochromic layer may be a photochromic material coated on the reflective layer, may be incorporated within the reflective layer, may be a separate photochromic layer, or any suitable combination thereof. Preferably, the at least one photochromic layer may comprise a photochromic material coated on a reflective layer.

[0015] The reflective layer may be fabricated from any suitable material, including, but not limited to, a metal foil (such as aluminium foil, aluminium foil laminates, and so on), metallised plastic films, and the like. In an embodiment of the invention, the reflective layer may be a metallised polyethylene. In a preferred embodiment of the invention, the reflective layer may comprise one or more aluminium foil sheets. In an embodiment of the invention, the reflective layer may have thermal insulation properties. Alternatively, the reflective layer may be associated with a material with thermal insulation properties. The reflective layer may be associated with a thermal insulating material by any suitable means. For instance, the reflective layer may be adhered to, coated on, or laminated to a thermal insulating layer.

[0016] In an embodiment where the reflective layer may comprise one or more aluminium foil sheets, it is envisaged that the aluminium foil sheets may be perforated. In this instance, it is envisaged that the perforations in the aluminium foil sheets may improve the circulation of air and help reduce or eliminate the formation of condensation. Alternatively, the aluminium foil sheets may be relatively dense and in use, it is envisaged that the dense insulation may provide a barrier to vapour penetration.

[0017] In an embodiment of the invention, the reflective layer may be provided with a coating. Any suitable coating may be used. For instance, the coating may act to reduce the reflective glare, reduce or eliminate corrosion, reduce or eliminate oxidisation, provide anti-slip properties, provide anti-scratch properties, modify the aesthetic appearance, and the like.

[0018] The reflective layer may be reinforced. Any suitable means of providing the reflective layer with reinforcing may be used. For instance, the reflective layer may be associated with a reinforcing layer, may be laminated or adhered to a reinforcing layer, may be coated on a reinforcing layer, or may be fabricated from a material comprising a reinforcing material (such as a fibre, a polymer, a mesh, a netting, or the like), or any suitable combination thereof. Preferably, however, the reinforcing improves the integral strength and tear resistance of the reflective layer and assists in providing the passive fall prevention device with resistance to impact, such that the likelihood of a roof installer or other worker falling through the passive fall prevention device is reduced or eliminated. In an embodiment of the invention, the reflective layer may be reinforced with a scrim layer. Any suitable scrim layer may be used. For instance, the scrim layer may be a fibreglass scrim, Kraft paper, a woven fabric layer, a polymer, or any suitable combination thereof. In use, it is envisaged that the reflective layer may be laminated to the scrim layer, although it will be understood that other techniques (such as the use of chemical adhesives, heat bonding and so on) may also be used.

[0019] The passive fall prevention device comprises at least one reinforcing layer. The reinforcing layers may be of the same type or may be of different types.

However, it will be understood that the type of reinforcing used may vary depending on a number of factors, such as the type of layer being reinforced and the desired properties of the layer being reinforced. For instance, the passive fall prevention device may comprise a reinforced reflective layer and a separate reinforcing layer, may comprise two reinforced reflective layers wherein the reinforcing material may be of the same type or of different types, may comprise a reinforced reflective layer and a reinforced thermal insulating layer, or any suitable combination thereof. Preferably, however, the reinforcing layers may provide the passive fall prevention device with resistance to impact. Thus, the at least one reinforcing layer may improve the mechanical strength of the passive fall prevention device. The at least one reinforcing layer may also improve the tear resistance of the passive fall prevention device.

[0020] The at least one reinforcing layer may be located in any suitable orientation in the passive fall prevention device. For instance, the at least one reinforcing layer may form an internal layer, may form an external layer, or any suitable combination thereof. In a preferred embodiment of the invention, the at least one reinforcing layer may form an internal layer of the passive fall prevention device.

[0021] The reinforcing layer may be fabricated from any suitable material, including, but not limited to, a metal or metal alloy (such as steel (including stainless steel, galvanised steel and so on), aluminium, and the like), a polymer (such as polypropylene, polyethylene, and the like) a fibreglass, a woven fabric, and the like. Preferably, however, the reinforcing layer may be fabricated from a material with sufficient mechanical properties (strength, rigidity, shape, etc.) to provide the passive fall prevention device with resistance to impact, such that the likelihood of a roof installer or other worker falling through the passive fall prevention device is reduced or eliminated.

[0022] In an embodiment of the invention, the reinforcing layer may be provided with a coating. In this instance, it is envisaged that the coating may provide the reinforcing layer with electrical insulation, corrosion resistance, and the like. Any suitable coating may be provided, such as paint, a powder coating, a polymer or rubber coating, an electrodeposited coating and so on, or any combination thereof.

[0023] The at least one reinforcing layer may be of any suitable size, shape and configuration. For instance, the reinforcing layer may comprise a woven filament layer, a non-woven filament layer comprising a plurality of reinforcing filaments, a sheet material, a plurality of longitudinal elements spaced apart from each other, an expanded grid, a polygon grid, a woven mesh, a netting, or any suitable combination thereof.

[0024] In an embodiment of the invention, the passive fall prevention device may comprise at least one thermal insulating layer. The thermal insulating layers may be of the same type or may be of different types. Preferably, however, the thermal insulating layers may provide a barrier against one or more of conductive heat, humidity, water and vapour penetration.

[0025] The at least one thermal insulating layer may be located in any suitable orientation in the passive fall prevention device. For instance, the at least one thermal insulating layer may form an internal layer, may form an external layer, or any suitable combination thereof. In a preferred embodiment of the invention, the at least one thermal insulating layer may form an internal layer of the passive fall prevention device.

[0026] The thermal insulating layer may comprise one or more layers. For instance, the thermal insulating layer may comprise a single layer or be a multilayer structure. The one or more layers of the thermal insulating layer may be fabricated from the same materials, the same type of materials, different materials, or different types of materials. The one or more layers may be fabricated from natural materials, synthetic materials or a combination thereof. In an embodiment of the invention, the thermal insulating layer may comprise an insulation material located between one or more outer layers. In an alternative embodiment, the thermal insulating layer may comprise an insulation material encapsulated between one or more outer layers, such that the insulation material may be substantially enclosed by the one or more outer layers.

[0027] The insulation material may be fabricated from any suitable material. For instance, the insulation material may be fabricated from an extruded polymer, an expanded polymer, a foamed polymer, or combinations thereof. Thus, the insulation material may be fabricated from a polymer (and especially a foamed polymer) such as, but not limited to, polyethylene, polypropylene, ethylene vinyl acetate, ethylene propylene diene terpolymer, polyethylene terephthalate, neoprene, nitrile, polyvinyl chloride, silicone, fluroelastomer, urethane, acrylonitrile butadiene styrene, or the like, or any suitable combination thereof. The insulation material may be fabricated from a closed cell insulation material or an open cell insulation material. In an embodiment of the invention, the insulation material may comprise a closed cell material. A closed cell material may have an open cell content of 20 % or less, 10 % or less, 5 % or less, and can have zero percent open cell content. In an alternative embodiment of the invention, the insulation material may comprise an open cell material. An open cell material may have an open cell content of 50 % or more, 60 % or more, 70 % or more, 80 % or more, 90 % or more and can have 100 % open cell content. In a preferred embodiment of the invention, the insulation material may be a closed cell polyethylene foam. In a preferred embodiment of the invention, the insulation material may be a cross-linked polyethylene foam.

[0028] The outer layers may be fabricated from any suitable material. For instance, the outer layers may be fabricated from a polymer such as, but not limited to, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, ethylene vinyl acetate, ethylene propylene diene terpolymer, acrylonitrile butadiene styrene, or the like, or any suitable combination thereof. In an embodiment of the invention, the outer layers may be a polyethylene sheet. For instance, the outer layers may be a low-density polyethylene sheet, a high-density polyethylene sheet, a cross-linked polyethylene sheet, or any suitable combination thereof. Preferably, however, the outer layers of the thermal insulating layer may be fabricated from materials which are relatively tear resistant and provide a barrier against conductive heat, humidity, water and vapour penetration. [0029] In an embodiment of the invention, the passive fall prevention device comprises at least one thermal insulating layer, wherein the at least one thermal insulating layer comprises a closed cell polyethylene foam sandwiched between a polyethylene sheet. In an alternative embodiment of the invention, the passive fall prevention device comprises at least one thermal insulating layer, wherein the at least one thermal insulating layer comprises a cross-linked polyethylene foam.

[0030] The thermal insulating layer may be reinforced. In an embodiment where the thermal insulating layer comprises one or more layers, one or more of the layers may be reinforced. Any suitable means of providing the thermal insulating layer with reinforcing may be used. For instance, the thermal insulating layer may be associated with a reinforcing layer, may be laminated or adhered to a reinforcing layer, or may be fabricated from a material comprising a reinforcing material (such as a fibre, a polymer, a mesh, a netting, or the like), or any suitable combination thereof. Preferably, however, the reinforcing improves the integral strength and tear resistance of the thermal insulating layer and assists in providing the passive fall prevention device with resistance to impact, such that the likelihood of a roof installer or other worker falling through the passive fall prevention device is reduced or eliminated.

[0031] The passive fall prevention device may comprise at least one photochromic layer. The photochromic layers may be of the same type or may be of different types. Preferably, however the photochromic layers may provide the passive fall prevention device with improved thermal resistance. Advantageously, the photochromic layers may provide the passive fall prevention device with improved thermal resistance together with high reflectivity and low emissivity.

[0032] The at least one photochromic layer may be located in any suitable orientation in the passive fall prevention device. For instance, the at least one photochromic layer may form an internal layer, may form an external layer, or any suitable combination thereof. In a preferred embodiment of the invention, the at least one photochromic layer may form an external layer of the passive fall prevention device. Thus, in this embodiment of the invention, the photochromic layer forms an outer facing of the passive fall prevention device. In use, it is envisaged that when the passive fall prevention device may be exposed to sunlight (and consequently exposed to ultraviolet radiation) during installation, the photochromic layer will transform from a light state to a darkened state. In this instance, the darkened photochromic layer may be provided with anti-glare properties. After the passive fall prevention device is installed and is no longer exposed to sunlight, it is envisaged that the photochromic layer will transform from a darkened state to a light state. In this instance, the photochromic layer in a light state may be provided with relatively high reflectivity and relatively low emissivity.

[0033] The photochromic layer may be of any suitable form. For instance, the photochromic layer may be provided by coating (including related techniques such as spraying, depositing or printing, or the like) a layer of the passive fall prevention device with a coating containing a photochromic dye(s), laminating a polymer containing photochromic dye(s) to a layer of the passive fall prevention device, incorporating photochromic molecule(s) directly into a layer of material used to form the passive fall prevention device (such as by impregnating the material with photochromic molecules, by incorporating the photochromic molecules in the layer during formation of the layer, or the like), and any suitable combinations thereof.

[0034] Any suitable type of photochromic material may be used to prepare the photochromic layer. For instance, the photochromic material may comprise chromenes, diarylethene, fulgide, azobenzene, naphthopyran, hydrazones, osazones, semicarbazones, anilines, disulfoxides, succinic anhydride, spiro compounds, and derivatives of stilbene, camphor, o-nitrobenzyl, or the like.

However, it will be understood that the type of photochromic material used may vary depending on a number of factors such as the type of photochromic layer being prepared, the degree of emissivity required of the passive fall prevention device and the size, shape and configuration of the passive fall prevention device.

[0035] The at least one photochromic layer may provide the passive fall prevention device with an emissivity of 0.03 to 0.9 epsilon, preferably an emissivity of 0.03 to 0.5, preferably 0.03 to 0.25, preferably 0.03 to 0.1, still more preferably 0.03 to 0.05.

[0036] In an embodiment of the invention, the at least one photochromic layer may comprise a photochromic coating applied to an external layer of the passive fall prevention device. In some embodiments of the invention, the photochromic coating may be applied to at least one reflective layer of the passive fall prevention device. Alternatively, the photochromic layer may form a reflective layer of the passive fall prevention device. Preferably, the photochromic coating may be applied to at least one reflective layer, wherein the at least one reflective layer may form an external layer of the passive fall prevention device. Thus, in this embodiment of the invention, the photochromic layer forms an outer facing of the passive fall prevention device.

[0037] In an embodiment of the invention, the passive fall prevention device may be at least partially fabricated from at least one flame retardant material. It will be understood that the term “flame retardant material” used throughout this specification refers to a compound or compounds which may prevent fires from starting or slow the spread of fires. It will be understood that the term “flame retardant material” may include compounds which enhance the efficacy of another compound.

[0038] The flame-retardant material may be located in any suitable orientation in the passive fall prevention device. For instance, in some embodiments of the invention the flame-retardant material may be present as one or layers of flame- retardant material within the passive fall prevention device. Alternatively, the at least one flame retardant material may be provided in the form of an adhesive applied to one or more layers of the passive fall prevention device (such as an adhesive layer, patch or the like), may be a flame retardant material incorporated into a polymer prior to, during, or after polymerisation, may be a coating of flame retardant material applied to a surface of one or more layers of the passive fall prevention device, or any suitable combination thereof. In a preferred embodiment of the invention, the at least one flame retardant material may comprise a flame-retardant material incorporated into a polymer in at least one layer of the passive fall prevention device. Preferably, the at least one flame retardant material may be incorporated into a polymer in the at least one thermal insulating layer. Alternatively, in an embodiment of the invention wherein the passive fall prevention device comprises at least one reflective layer fabricated from a polymer or associated with a polymer, the at least one flame retardant material may be incorporated into the polymer. Alternatively, in an embodiment of the invention wherein the passive fall prevention device comprises at least one reinforcing layer fabricated from a polymer, the at least one flame retardant material may be incorporated into the polymer. Alternatively, in an embodiment of the invention of the invention wherein the passive fall prevention device comprises a scrim layer fabricated from a polymer, the at least one flame retardant material may be incorporated into the polymer. However, it will be understood that whether the flame retardant material may be incorporated into a particular layer of the passive fall prevention device will depend on a number of factors, including the type of polymer in the layer, the amount of polymer in the layer and whether the inclusion of the flame retardant material impacts the desired properties of the polymer. Preferably, the at least one flame retardant material may be incorporated into polyethylene in at least one layer of the passive fall prevention device.

[0039] The flame-retardant material may be of any suitable type. For instance, the flame retardant material may comprise an inorganic flame retardant (such as a metal hydroxide, boron salts, inorganic antimony, tin, zinc or molybdenum compounds, elemental red phosphorus), organophosphorus flame retardants, nitrogen-based organic flame retardants, and halogenated flame retardants (such as those based on bromine and chlorine), and the like, or any suitable combination thereof. In an embodiment of the invention, the at least one flame retardant material may comprise an inorganic flame retardant. In a preferred embodiment of the invention, the flame-retardant material may comprise a source of magnesium and a source of antimony. Preferably, the flame-retardant material may comprise magnesium hydroxide and antimony trioxide.

[0040] Surprisingly, it has been found that antimony trioxide enhances the flame- retardant efficacy of magnesium hydroxide and provides the polymer with relatively high fire resistance and relatively low smoke development during a fire. Surprisingly, it has been found that a flame-retardant material comprising antimony oxide and magnesium hydroxide may be mixed with polyethylene to form a substantially homogenous material.

[0041] In an embodiment of the invention, the passive fall prevention device comprises at least one reflective layer; at least one thermal insulating layer; at least one reinforcing layer, and at least one photochromic layer, wherein the passive fall prevention device is at least partially fabricated from at least one flame retardant material. In a preferred embodiment of the invention, the passive fall prevention device comprises at least one reflective layer; at least one thermal insulating layer; at least one reinforcing layer, and at least one photochromic layer, wherein the at least one thermal insulating layer is at least partially fabricated from at least one flame retardant material.

[0042] In an embodiment of the invention, the passive fall prevention device may comprise at least one amorphous carbon material. It will be understood that the term “amorphous carbon material” used throughout this specification refers to a free, reactive carbon material that does not have a crystalline structure.

[0043] In some embodiments of the invention, the amorphous carbon material may be provided as one or more layers of amorphous carbon material within the passive fall prevention device. Alternatively, the at least one amorphous carbon material may be located in any suitable layer of the passive fall protection device. Preferably, the at least one amorphous carbon material may be incorporated into a polymer prior to, during, or after polymerisation. Surprisingly, it has been found that the inclusion of the at least one amorphous carbon material disrupts the crystalline structure of the polymer, decreasing thermal conductivity and increasing thermal resistance. Further, the inclusion of the at least one amorphous carbon material increases the tensile and break strength of the polymer.

[0044] In a preferred embodiment of the invention, the at least one amorphous carbon material may be incorporated into a polymer in at least one layer of the passive fall prevention device. Preferably, the at least one amorphous carbon material may be incorporated into a polymer in the at least one thermal insulating layer. Alternatively, in an embodiment of the invention wherein the passive fall prevention device comprises at least one reflective layer fabricated from a polymer or associated with a polymer, the at least one amorphous carbon material may be incorporated into the polymer. Alternatively, in an embodiment of the invention wherein the passive fall prevention device comprises at least one reinforcing layer fabricated from a polymer, the at least one amorphous carbon material may be incorporated into the polymer. Alternatively, in an embodiment of the invention of the invention wherein the passive fall prevention device comprises a scrim layer fabricated from a polymer, the at least one amorphous carbon material may be incorporated into the polymer. However, it will be understood that whether the amorphous carbon material may be incorporated into a particular layer of the passive fall prevention device will depend on a number of factors, including the type of polymer in the layer, the amount of polymer in the layer and whether the inclusion of the amorphous carbon material impacts the desired properties of the polymer. Preferably, the at least one amorphous carbon material may be incorporated into polyethylene in at least one layer of the passive fall prevention device.

[0045] The amorphous carbon material may be of any suitable type. For instance, the amorphous carbon material may comprise coal, soot, carbide derived carbon, and the like, or any suitable combination thereof.

[0046] In an embodiment of the invention, the passive fall prevention device comprises at least one reflective layer; at least one thermal insulating layer; at least one reinforcing layer, and at least one photochromic layer, wherein the passive fall prevention device is at least partially fabricated from at least one amorphous carbon material. In a preferred embodiment of the invention, the passive fall prevention device comprises at least one reflective layer; at least one thermal insulating layer; at least one reinforcing layer, and at least one photochromic layer, wherein the at least one thermal insulating layer is at least partially fabricated from at least one amorphous carbon material.

[0047] In an embodiment of the invention, the passive fall prevention device may be at least partially fabricated from at least one flame retardant material and at least one amorphous carbon material. Preferably, the at least one flame retardant material and the at least one amorphous carbon material may be incorporated into a polymer in at least one layer of the passive fall prevention device. The at least one flame retardant material and the at least one amorphous carbon material may be incorporated into the same polymer or into different polymers. In an embodiment where the polymer-containing layer of the passive fall prevention device may comprise two or more polymers, the at least one flame retardant material and the at least one amorphous carbon material may be incorporated into the same polymer or into different polymers. Preferably, the at least one flame retardant material and the at least one amorphous carbon material may be incorporated into a polymer in the at least one thermal insulating layer, into a polymer in the at least one reflective layer, or any suitable combination thereof. [0048] In an embodiment of the invention, the passive fall prevention device comprises at least one reflective layer; at least one thermal insulating layer; at least one reinforcing layer, and at least one photochromic layer, wherein the passive fall prevention device comprises one or more of the group consisting of at least one flame retardant material, at least one amorphous carbon material.

[0049] The present invention provides a number of advantages over the prior art. For instance, the present invention has improved thermal resistance and decreased thermal conductivity resulting in an improved thermal resistance of the entire roof and reducing cooling and heating requirements. The present invention also enables a worker to use the invention in a roof space without separately installing safety meshes or netting to provide fall protection for roof installers and offer long-term protection against falling for maintenance and repair workers.

[0050] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0051] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0052] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0053] Figures 1a and 1b illustrates a diagrammatic view of a passive fall prevention device according to an embodiment of the invention. [0054] Figures 2a and 2b illustrates a diagrammatic view of a passive fall prevention device with a separate reinforcing layer according to an embodiment of the invention.

[0055] Figure 3 illustrates a diagrammatic view of a roof construction comprising a passive fall prevention device according to an embodiment of the invention in use.

DESCRIPTION OF EMBODIMENTS

[0056] Figures 1a and 1b illustrate a diagrammatic view of a passive fall prevention device according to an embodiment of the invention. Passive fall prevention device is generally indicated by arrow 100. Passive fall prevention device 100 may be used as an insulation material in roof spaces and is a multi-layer structure. Passive fall prevention device comprises at least one reflective layer 12, at least one thermal insulating layer 14, and at least one reinforcing layer 15. At least one photochromic layer 16 is applied to at least one of the at least one reflective layers 12.

[0057] The at least one reflective layer 12 may be laminated to a reinforcing layer 15 (as illustrated in Figure 1b) which improves the mechanical strength and tear resistance of reflective layer 12. In use, it is envisaged that the passive fall prevention device 100 may be provided with an upper reflective layer and a lower reflective layer, such that the upper reflective layer and the lower reflective layer form external layers of the passive fall prevention device 100 and the thermal insulating layer 14 may be substantially encapsulated therein. One or both of the upper reflective layer and the lower reflective layer may be provided with a reinforcing layer, where the reinforcing layer may be laminated, coated, sprayed, or the like onto the reflective layer.

[0058] The at least one reflective layer 12 illustrated in Figures 1a and 1b comprises an aluminium foil layer. The entire reflective layer 12 may comprise aluminium foil, or an external surface 13 of the reflective layer 12 may comprise aluminium laminated to or deposited on a plastic sheet. Photochromic layer 16 comprises a photochromic coating applied to an external surface 13 of reflective layer 12 such that the photochromic layer forms an outer facing of the passive fall prevention device. It is envisaged that in use, the passive fall prevention device 100 is installed in a roof space such that the external surface comprising photochromic layer 16 is exposed to sunlight during installation. In use, photochromic layer 16 will transform from a light state to a darkened state when exposed to ultraviolet radiation reducing the glare.

[0059] The thermal insulating layer 14 forms an internal layer of the passive fall prevention device 100 and is substantially enclosed by the reflective layer 12 and the photochromic layer 16 of the passive fall prevention device 100. Thermal insulating layer 14 may comprise a closed cell polyethylene foam. Optionally, thermal insulating layer 14 may be provided with a reinforcing layer (not shown) which improves the mechanical strength and tear resistance of thermal insulating layer 14 and assists in providing the passive fall prevention device 100 with resistance to impact, such that the likelihood of a roof installer or other worker falling through the passive fall prevention device 100 is reduced or eliminated.

[0060] Thermal insulating layer 14 may comprise a flame retardant material (such as magnesium hydroxide and antimony trioxide) or an amorphous carbon material.

In use, it is envisaged that the flame retardant materials provide the thermal insulating layer 14 with relatively high fire resistance and/or relatively low smoke development during a fire. In use, it is envisaged that the amorphous carbon material decreases the thermal conductivity and increases thermal resistance of the thermal insulating layer 14.

[0061] Figures 2a and 2b illustrate a diagrammatic view of a passive fall prevention device according to an alternative embodiment of the invention. The passive fall prevention device is generally indicated by arrow 200. Passive fall prevention device 200 may be used as an insulation material in roof spaces and is a multi-layer structure. Passive fall prevention device 200 comprises at least one reflective layer 22, at least one thermal insulating layer 24, at least one reinforcing layer 28 and at least one photochromic layer 26. As illustrated in Figure 2b, one or both of the upper reflective layer and the lower reflective layer may be provided with a further reinforcing layer 25, where the reinforcing layer may be laminated, coated, sprayed, or the like onto the reflective layer. [0062] The at least one reflective layer 22 illustrated in Figures 2a and 2b comprises an aluminium foil layer and forms an external layer of the passive fall prevention device 200. Photochromic layer 26 comprises a photochromic coating applied to an external surface 23 of at least one of the reflective layers 22 such that the photochromic layer forms an outer facing of the passive fall prevention device.

[0063] The at least one thermal insulating layer 24 and the at least one reinforcing layer 28 form internal layers of the passive fall prevention device 200 and are substantially enclosed by an upper reflective layer and a lower reflective layer of the passive fall prevention device. Thermal insulating layer 24 comprises a closed cell polyethylene foam and may be reinforced, or provided with a reinforcing layer. Reinforcing layer 28 comprises a mesh fabricated from a material with sufficient mechanical properties (strength, rigidity, shape, etc.) to provide the passive fall prevention device with resistance to impact, such that the likelihood of a roof installer or other worker falling through the passive fall prevention device is reduced or eliminated.

[0064] Optionally thermal insulating layer 24 comprises a flame-retardant material such as magnesium hydroxide and antimony trioxide and/or an amorphous carbon material.

[0065] Figure 3 illustrates a diagrammatic view of a roof construction comprising a passive fall prevention device according to an embodiment of the invention in use. Roof construction is generally indicated by arrow 300. Passive fall prevention device 50 is located in the roof space defined by roof sheeting 52 and plasterboard 56. Passive fall prevention device 50 is oriented such that reflective layer comprising a photochromic coating is facing outwardly towards roof sheeting 52, such that this surface is exposed to sunlight during installation, and a lower reflective layer without photochromic coating is oriented such that it faces inwardly towards plasterboard 56. Air gap 54 provides a barrier to heat transfer.

[0066] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers. [0067] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0068] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.