AU2020100996B4

AU2020100996B4 - An access panel and an associated method

Info

Publication number: AU2020100996B4
Application number: AU2020100996A
Authority: AU
Inventors: John RAKIC
Original assignee: Rakman International Pty Ltd
Current assignee: Rakman International Pty Ltd
Priority date: 2020-05-22
Filing date: 2020-06-12
Publication date: 2021-02-25
Anticipated expiration: 2028-06-12
Also published as: AU2021200430A1; AU2020100996A4

Abstract

The access panel 1 is a passive fire protection product that is suitable for installing into a barrier. The access panel has a frame 3 housing the planar panel 2. The frame 3 has a cross sectional profile extending continuously between a first end 6 and a second end 7. A thermal break 8 is disposed at the first end 6. The thermal break 8 is formed from a material having a thermal conductivity of less than 20 watts per meter per Kelvin. A range of materials may be suitable for the thermal break 8 and the material used in the illustrated embodiment is polyvinyl chloride.

Description

AN ACCESS PANEL AND AN ASSOCIATED METHOD TECHNICAL FIELD

The present invention relates to an access panel, which may be used, for example, to provide an access point through a barrier such as a wall, ceiling, floor, floor/ceiling system, etc. It also relates to an associated method. Embodiments of the present invention find application in the field of passive fire protection.

BACKGROUNDART

Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of this application.

Prior art access panels are known whereby a door is hingedly or mechanically connected to a metal frame that is mounted to the surface through which access may be required. It is desirable for such access units to exhibit integrity characteristics (i.e. where the product provides resistance to the passage of flames or hot gasses for a predetermined time), mechanical strength characteristics (i.e. to withstand the forces that are likely to be generated during installation and when a person passes through the access panel) and insulation characteristics (i.e. where one side of the product is exposed to an elevated temperature and the other side of the product must not exceed a pre-determined temperature rise within a predetermined time). For the purposes of this specification, the meanings for integrity and insulation are those adopted by AS1530.4:2014.

It has been appreciated by the inventor of the present application that typical prior art access panels perform relatively well in relation to the integrity and mechanical strength characteristics; however, they typically perform poorly in relation to the insulation characteristics. This is illustrated, for example, in figure 1, which depicts the maximum temperature rise in a fire test report for a 450mm x 450 mm fire rated access panel having a traditional steel frame. The solid green line shows the temperature rise as measured on the unexposed face of the frame and this exceeds the 180 temperature rise limit after approximately 17 minutes. The test results include an integrity rating, which is a measure of the samples ability to prevent the passage of flames and hot gasses. The test results also include an insulation rating, which is a measure of the sample's ability to prevent temperature rise on a side of the access panel that is not exposed to a heat source. For the traditional prior art sample in this specific example, the integrity value was 92 minutes and the insulation value was 17 minutes.

In an attempt to improve the insulation characteristics of the prior art units, it is known to require the installer of the access panel to add an insulative cladding that is supposed to be installed after the access panel has been fixed in position, or for the supplier to provide such a cladding with the product as it is sold. However, such claddings take up space within the opening provided by the access panel, may be easily damaged and/or not aesthetically pleasing, and it has been appreciated by the inventor that occasionally the installer may damage or completely omit to install such insulative claddings.

The applicant has a co-pending Australian Patent Application No. 2016201430 in which a thermal break 9 is disposed intermediate first and second frames 3 and 11. It has been appreciated by the inventor that in some circumstances, and depending upon the specific materials and construction techniques used, the 2016201430 prior art sample may not cope with typical stresses and strains likely to be exerted upon it during its installation and/or its usage.

It has also been appreciated by the inventor that it would be desirable to provide an alternative access panel having a potential to exhibit improved insulation values, along with stronger mechanical properties and facilitating ease of manufacture.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome, or substantially ameliorate, one or more of the disadvantages of the prior art, or to provide a useful alternative.

In one aspect of the present invention there is provided an access panel having: a frame removably housing a planar panel, the frame being configured for attachment to an opening of a barrier, the frame being composed of frame elements each having a transverse cross-sectional profile defining a path of heat conduction extending between a first end adjacent to an outer side of the planar panel and a second end adjacent to an inner side of the planar panel; and a thermal break disposed on at least the first end, the thermal break being formed from a material having a thermal conductivity of less than 20 watts per meter per Kelvin, wherein the thermal break material is, or includes, at least one of: a plastics material, including polyvinyl chloride or unplasticised polyvinyl chloride, intumescent plastics, recycled plastics, glass fiber reinforced plastics, low volatility plastics or a co-extruded plastic/intumescent material; gypsum; an intumescent material; a timber material; calcium-silicate; magnesium oxide; or a material having a lower melting point than autoignition point, wherein the transverse cross-sectional profile of each of the frame elements extends continuously between the first end and the second end and wherein: a first piece of intumescent material is disposed on an exterior side of the frame and/or a second piece of intumescent material is disposed on an interior side of the frame.

Preferably the frame is made from at least one of the following materials: a metallic material, including steel, stainless steel or sheet metal; a thermoplastics material; timber; or an intumescent impregnated plastics material.

Preferably the planar panel is hingedly attached to the frame or is secured to the frame by at least one fastener.

In one embodiment a first portion of the frame element defining the first end is disposed adjacent to an edge face of the planar panel and the thermal break has an L-shaped cross-sectional profile defining a first section and a second section, the first section of the L shaped profile abutting an interior side of the first portion of the frame element, the second section of the L-shaped profile extending across the first end so as to project outwardly from an exterior side of the first portion of the frame element. Preferably the first portion is disposed adjacent and parallel to edge faces of the planar panel and the first portion has a length less than a thickness of the planar panel at the outer edge.

The features and advantages of the present invention will become further apparent from the following detailed description of preferred embodiments, provided by way of example only, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a graph showing temperature rises experienced during testing of a first prior art access panel; Figure 2 is a front view of an embodiment of the invention; Figure 3 is a plan view of the embodiment; Figure 4 is a frontal/upper perspective view of the embodiment; Figure 5 is a rear wireframe view of the embodiment; Figure 6 is a plan wireframe view of the embodiment; Figure 7 is a rear/upper perspective wireframe view of the embodiment; Figure 8 is a front view of the embodiment showing line E-E; Figure 9 is a sectional view of the embodiment, as seen through line E-E; Figure 10 is a detail sectional view showing the region marked F in figure 9; Figure 11 is a front view of the embodiment showing line I-I; Figure 12 is a sectional view of the embodiment, as seen through line I-I; Figure 13 is a detail sectional view showing the region marked J in figure 12; and Figure 14 is a graph showing frame temperature rises as experienced during testing of the embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The contents of co-pending Australian Patent Application No. 2016201430 are hereby incorporated in their entirety by way of reference.

Referring to the drawings, the access panel 1 is a passive fire protection product that is suitable for installing into an opening of a barrier, such as a wall, a ceiling, a floor, a floor/ceiling system, or the like. In many typical implementations, the barrier will be a fire rated barrier and the access panel 1 is intended to provide an access point through the barrier without substantially compromising the fire rating of the barrier 1 (that is, of course, whilst the planar panel 2 of the access panel 1 is in a closed position so as to seal off the opening created by the access panel).

The access panel has a frame 3 removably housing the planar panel 2. The planar panel 2 is a fire rated panel (which is commonly known within the industry as a "leaf') and may have at least one face laminated with a fire-resistant plastics compound and/or graphite or fire resistant additives. The planar panel 2 in the illustrated preferred embodiment is hingedly attached to the frame 3 via three standard cupboard-style hinges 4 as best shown in figures 5 and 7. It is desirable, but not essential, for the hinges to be concealed on the "back" face of the planar panel 2. Fasteners, such as screws, rivets, or the like, attach the hinges 4 to the planar panel 2 and to the frame 3. This allows the planar panel 2 to function as a door that can swing between an open and a closed position. When in the closed position, the planar panel 2 is restrained from inadvertent opening by a latch assembly 19, which positions a latch 22 within slot that is disposed in the frame 3.

In another embodiment the planar panel 2 is secured to the frame 3 with removable fasteners such as screws, rivets, or the like.

In yet another embodiment the planar panel 2 incorporates the supplementary insulating system as disclosed in Australian Provisional Patent Application No. 2020901813. The contents of Australian Provisional Patent Application No. 2020901813 are hereby incorporated in their entirety by way of reference.

The frame 3 comprises four sheet metal sections referred to herein as "frame elements" that are interconnected, for example by spot welding or any other suitable joining method, so as to form a substantially square or rectangular shaped frame structure. It will be appreciated, however, that the frame structures of other embodiments may be shaped differently, such as triangular, circular, and so forth and the term "frame elements" as used in this document, including in the claims, is to be construed broadly so as to read onto such other frame shapes. In another embodiment the frame 3 does not fully encircle the panel 2. Rather, in this embodiment the panel is in the form of a rectangular fire door and the frame wraps around the top and the sides of the rectangle but the frame does not extend across the bottom of the fire door.

The frame 3 is configured for attachment to the opening of the external barrier by the provision of four fixing holes 5 that are disposed generally evenly along each of the frame's four sides. In use, fasteners, such as screws, bolts, or the like, extend through each of these holes 5 so as to affix the access panel 1 to the barrier.

As best shown for example in figures 9, 10, 12 and 13, the frame 3 has a transverse cross-sectional profile defining a path of heat conduction extending continuously between a first end 6 that is adjacent to an outer side of the planar panel and a second end 7 that is adjacent to an inner side of the planar panel. This frame 3 is formed, for example, by bending or roll forming, into a number of straight portions separated by bends. The first straight portion 11 of the frame 3 terminates at the first end 6. For the illustrated embodiment of the access panel 1, in which the planar panel 2 is hingedly connected to the frame 3, the first straight portion 11 is disposed adjacent and parallel to the edge faces 13 of the planar panel 2 when the planar panel 2 is in the closed position.

In the illustrated preferred embodiment, the frame 3 is made from steel sheet, which has low thermal conductivity compared to many other metals and good strength properties. However, other sheet metals and other metallic materials such as stainless steel and the like would also be suitable for alternative embodiments. Other options include thermoplastics materials, timber and intumescent impregnated plastics materials. In the case of intumescent impregnated plastics materials, exposure of the frame 3 to the heat of a fire causes the intumescent material to expand, which would typically block the planar panel 2 from opening. This is advantageous to help avoid opening or removal of the planar panel 2 when the access panel 1 is being exposed to a fire. This helps ensure that the fire does not breach the access panel 1.

The frame 3 of another embodiment is made from a composite mesh (which contributes strength) and an intumescent plastics compound (for fire performance). This material allows for the frame 3 to be injection moulded, pultruded or extruded.

The thermal break 8 is disposed at the first end 6, however in some alternative embodiments one or more additional thermal breaks may be disposed at other positions on the frame 3.

The thermal break 8 is formed from a material having a thermal conductivity of less than 20 watts per meter per Kelvin, although in other embodiments the thermal conductivity may be less than 15 watts per meter per Kelvin, 10 watts per meter per Kelvin, 5 watts per meter per Kelvin, 1 watt per meter per Kelvin or 0.5 watts per meter per Kelvin. A range of plastics materials may be suitable for the thermal break 8 and the material used in the illustrated preferred embodiment is regular polyvinyl chloride, however unplasticised polyvinyl chloride may also be utilised in some alternative embodiments. The thermal break material may also include graphite and other fire-resistant additives. In some embodiments the thermal break material may be produced from waste materials.

A desirable characteristic for the thermal break material is that its breakdown under fire conditions does not lead to high flammability, which is exhibited for example by low volatility plastics.

Other options include the thermal break material recycled plastics, glass fiber reinforced plastics, gypsum and intumescent materials such as intumescent plastics and co extruded plastic/intumescent materials. Yet further options include timber, calcium-silicate and magnesium oxide.

Another desirable characteristic for the thermal break material, particularly the plastics-based materials, is having a substantially lower melting point than autoignition point. This ensures that if the thermal break 8 gets too hot it will melt and fall away prior to any autoignition. Once the thermal break 8 has melted and dropped away, further heat transfer becomes effectively impossible (other than through the atmosphere) as there is no longer any material through which to conduct heat. In this circumstance the external intumescent 9 mentioned in more detail below functions to block the gaps created by the melted thermal break 8.

Examples of further suitable materials from which to form the thermal break 8 include calcium silicate boards, such as Orbit FR Board, which has a thermal conductivity of approximately 0.137 watts per meter per Kelvin or Maxilite board, which has a thermal conductivity of approximately 0.14 watts per meter per Kelvin. Another example of a suitable material is Promatect H board, which has a thermal conductivity of approximately 0.242 W/m.K, as sold by Promat Australia Pty Ltd in Adelaide, South Australia. Further examples include Vermiclux and Supalux, which each have a conductivity of less than 5

W/m.K, or Monolux, which has a thermal conductivity of approximately 0.18 W/m.K, as sold by Intumex Asia Pacific in Northmead, NSW, Australia. Another example is Fyrchek Plasterboard, which has a thermal conductivity of approximately 0.18 W/m.K, as sold by CSR Gyprock in Sydney, NSW, Australia. It will be appreciated by those skilled in the art that other materials, such as magnesium oxide, graphite and/or high melting point thermoplastics for example, may be utilised to form the thermal break 8.

The thermal break 8 may be attached to the first end 6 of the frame 3 by fasteners, such as rivets, clips or other mechanical fixings. Adhesives provide another attachment option, such as the use of double-sided adhesive tape. Another option is to form a slot in the thermal break 8 that is sized to interference fittingly receive a length of the first portion 11.

As best shown in figures 10 and 13, a first piece of intumescent material 9 is disposed on an exterior side of the first portion 11 of the frame 3 and a second piece of intumescent material 10 is disposed on an interior side of the frame. Expansion of the first piece of intumescent material 9 in response to the heat of a fire helps ensure that gaps between the frame 3 and the external barrier may be sealed. Similarly, expansion of the second piece of intumescent material 10 helps ensure that gaps between the frame 3 and the planar panel 2 may be sealed. However, some alternative embodiments feature only one or the other of the first piece of intumescent material 9 or the second piece of intumescent material 10.

As best shown in figures 10 and 13, the thermal break 8 has an L-shaped cross sectional profile defining a first section 16 and a second section 17. The first section 16 abuts an interior side of the first portion 11 of the frame element. This overlap is the region at which the thermal break 8 is attached to the first portion 11. The second section 17 of the L shaped profile extends across the first end 6 so as to project outwardly from an exterior side of the first portion of the frame element and thereby frame the planar panel 2, as best shown in figure 2. This is typically referred to within the industry as an architrave. In some embodiments the L-shape includes a chamfer or other shaping for improved aesthetics, for example to provide a "picture frame" look. The four second sections 17 together form a flange that in use is parallel to, and bears externally upon, an outer surface of the barrier into which the access panel 1 is to be installed. In use, the remainder of the access panel 1 (i.e. all of the access panel 1 other than the flange formed by the set of second sections 17) is inserted into a hole in the external barrier.

As best seen in figures 10 and 13, the first portion 11 of the frame 3 has a length less than the thickness of the edge faces 13 of the planar panel 2 at the edge face. More specifically, the length of the first portion 11 is approximately equal to 70% of the width of the planar panel 2. Hence, the first end 6 is spaced back from the outer surface 12 of the planar panel 2. This ensures that the path of heat conduction provided by the frame 3 towards the outer surface 12 terminates at the first end 6. From this point, the available thermal conduction paths are either along the first section 16 of the thermal break 8 or along the exterior intumescent material 9.

A bend 14 at the other end of the first portion 11 of the frame 3 connects a second straight portion 15 of the frame 3 to the first portion 11. The second portion 15 is configured to be disposed adjacent the periphery of the planar panel 2. For the embodiment in which the planar panel 2 is hingedly connected to the frame 3, the second portion 15 acts as a door stop. The second piece of intumescent material 10 is disposed intermediate the periphery of the planar panel 2 and an interior side of the second portion 15 of the frame 3.

A third portion 18 of the frame 3 terminates at the second end 7. As can be best seen in figures 10 and 13, the third portion 18 has an open box section, which projects transversely from the second portion 15. This open box section contributes strength to the overall access panel structure and provides a sturdy anchoring point for fastening of the frame 3 to the external barrier.

As best shown in figures 12 and 13, a latch assembly 19 is disposed on the planar panel 2 into which a key may be inserted through opening 20. A cylindrical piece of intumescent material 21 is disposed adjacent to the opening 20 of the latch assembly 19. In response to the heat of a fire, this intumescent material 21 expands so as to prevent passage of flames and hot gases through the opening 20 and the latch assembly 19.

The method of installing the access panel 1 into a barrier entails forming a hole within the barrier that is just large enough to receive the access panel (with the exception of the external flange formed by the second sections 17 of the thermal break 8, which rest flush against the outer surface of the barrier). Once the access panel 1 has been inserted into the hole in the barrier, fasteners such as rivets, bolts, screws, or the like are driven through holes to fasten the access panel 1 to the barrier. Importantly, it is not necessary to use any preinstalled insulative cladding materials or additional thermally insulative material as cladding to the frame 3 when installing the preferred embodiment because of the thermal insulation properties provided by the thermal break 8.

Fire test results for the illustrated embodiment, having dimensions of 600 mm x 600 mm, are illustrated in figure 14. The temperature rise curves over time as measured by five sensors positioned upon the frame 3 of the test sample on a side not exposed to a heat source are plotted by the variously coloured lines. It is the purple line that is of greatest interest, which relates to the measurements of a temperature sensor labelled 031. This is the first sensor to measure a temperature rise on the frame 3 that exceeded the 180 temperature rise limit. The test results for the frame 3 of this sample yield an integrity value of 121 minutes and an insulation value of 72 minutes. It can be seen from a comparison with the prior art test results shown in figure 1, along with the above discussion of the prior art, that this embodiment of the invention exhibited better integrity and insulation values. Additionally, it is believed that the continuous frame design will assist this embodiment to cope with typical stresses and strains likely to be exerted upon it during its installation and subsequent usage.

Further, a failure of the thermal break 8 of the embodiment of the invention, for example, due to it melting, would most likely be much less structurally significant as compared to a failure of the intermediate portion of the prior art access panel disclosed in co pending Australian Patent Application No. 2016201430.

Importantly, the embodiment of the invention is also easier and cheaper to manufacture in both labour and material costs as compared to the 2016201430 prior art. This is mainly because securing insulating boards between the two metal frames of the 2016201430 prior art is time consuming and unreliable from a manufacturing perspective.

While a number of preferred embodiments have been described, it will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An access panel having: a frame removably housing a planar panel, the frame being configured for attachment to an opening of a barrier, the frame being composed of frame elements each having a transverse cross-sectional profile defining a path of heat conduction extending between a first end adjacent to an outer side of the planar panel and a second end adjacent to an inner side of the planar panel; and a thermal break disposed on at least the first end, the thermal break being formed from a material having a thermal conductivity of less than 20 watts per meter per Kelvin, wherein the thermal break material is, or includes, at least one of: a plastics material, including polyvinyl chloride or unplasticised polyvinyl chloride, intumescent plastics, recycled plastics, glass fiber reinforced plastics, low volatility plastics or a co-extruded plastic/intumescent material; gypsum; an intumescent material; a timber material; calcium-silicate; magnesium oxide; or a material having a lower melting point than autoignition point, wherein the transverse cross-sectional profile of each of the frame elements extends continuously between the first end and the second end and wherein: a first piece of intumescent material is disposed on an exterior side of the frame; and/or a second piece of intumescent material is disposed on an interior side of the frame.

2. An access panel according to claim 1 wherein the frame is made from at least one of the following materials: a metallic material, including steel, stainless steel or sheet metal; a thermoplastics material; timber; or an intumescent impregnated plastics material and wherein the planar panel is hingedly attached to the frame or is secured to the frame by at least one fastener.

3. An access panel according to any one of the preceding claims wherein a first portion of the frame element defining the first end is disposed adjacent to an edge face of the planar panel and wherein the thermal break has an L-shaped cross-sectional profile defining a first section and a second section, the first section of the L-shaped profile abutting an interior side of the first portion of the frame element, the second section of the L-shaped profile extending across the first end so as to project outwardly from an exterior side of the first portion of the frame element.

4. An access panel according to claim 3 wherein the first portion is disposed adjacent and parallel to edge faces of the planar panel and wherein the first portion has a length less than a thickness of the planar panel at the edge face.