AU2016238895A1

AU2016238895A1 - Inflatable bodies having improved resistance to thermal radiation transmission

Info

Publication number: AU2016238895A1
Application number: AU2016238895A
Authority: AU
Inventors: Douglas JACOT; James Marson
Original assignee: Cascade Designs Inc
Current assignee: Cascade Designs Inc
Priority date: 2011-01-20
Filing date: 2016-10-06
Publication date: 2016-10-20
Also published as: JP6239679B2; AU2012207091B2; NZ613789A; CN103402401B; CN105640148A; CA2825376A1; CN103402401A; CA2825376C; AU2012207091A1; JP2014502916A; WO2012100236A1; JP2016172015A; JP5931925B2

Abstract

INFLATABLE BODIES HAVING IMPROVED RESISTANCE TO THERMAL RADIATION TRANSMISSION An inflatable body (10) comprising: first and second substantially opposing side panels (20a and 20b), coupled to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a tensile structure disposed within the envelope and coupled to inner surfaces of the opposing side panels (20a and 20b); and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to at least one of the opposing side panels (20a and 20b) to define an air-filled chamber exclusive of the tensile structure when the body (10) is in an inflated state.

Description

Inflatable Bodies Having Improved Resistance to Thermal

Radiation Transmission

Background of the Invention

Thermal performance data disclosed herein was obtained using a temperature controlled test chamber held at 4°C in which prior art inflatable bodies and a plurality of inflatable bodies constructed according to the invention embodiments were subjected to an insulated heat source (a three zone guarded heat plate operatively linked to a computer) on one side and heat sink (a large aluminum plate with a plurality of temperature probes also linked to a computer) exposed to the controlled environment on the other side. The thermal performance of a subject mattress was then established by determining the amount of electrical power needed to maintain the heat source at a constant temperature of 33.3°C while also maintaining the temperature of the heat sink at the ambient temperature. Once stabilized, the amount of electrical power needed to maintain this steady state correlated with the heat energy passing from the heat source, through the subject mattress and into the heat sink, and ultimately rejected into the environment. In this manner, the electrical equivalent of the thermal transmission rate could be determined.

These tests indicated that prior art inflatable bodies comprising an expanded polyurethane foam core co-extensively bonded to opposing panels have thermal insulation values of about R-3 for 1" (~2.5 cm) thick cores, about R-5 for 2" (~5.0 cm) thick cores, and about R-7 for 3" (~7.5 cm) thick cores. These tests also indicated that conventional inflatable bodies such as non-baffled air mattresses of about 2.5" (-6.25 cm) thickness have a thermal insulation value of about R-1 when constructed from polymeric films of the type referenced herein. By introducing a conventional film-based bisecting baffle to compartmentalize "upper" and "lower" portions of such inflatable bodies, heat loss from thermal convection was significantly reduced, as reflected by a doubling of the thermal insulation value to about R-2.

However, if additional meaningful thermal insulation gains for such non-foam core inflatable bodies are desired, it becomes necessary to address heat transfer modes other than thermal convection; since thermal conduction is not a meaningful contributor in such mattresses, the remaining mode is thermal radiant transmission.

To mitigate this mode of heat transfer, a metalized polymeric bisecting film can be substituted for the non-metalized bisecting film in the previously described baffled inflatable body, as is taught in the prior art. The result of this substitution yields an increase in thermal insulation performance of about one additional "R" value, e.g., to about R-3, when the film has a 1.0 optical density.

International publication number WO 2009094208 A2, which is incorporated herein by reference, discloses inflatable bodies having a cellular matrix core comprised of various materials wherein substitution of certain matrix core components with metalized film and/or metalization of existing materials (whether planar, corrugating or panel) provides possible means for mitigating heat transfer via thermal radiation transmission through such inflatable bodies. While this publication does not disclose or suggest any details concerning such substitution or treatment, it does identify issues pertaining to compatible bonding interface requirements at page 4. Still, it offers no details concerning the inflatable body structure(s) to which it would be bonded. Moreover, there is no disclosure concerning which mode for mitigating heat transfer via thermal radiation transmission is preferable or more efficacious, other than the disclosure on pages 12 -13: "...a preferred embodiment of the invention comprises a foam planar sheet to which is selectively bonded at least one non-woven or batting-type material as a serpentine or corrugating sheet, and at least one envelope panel having a radiant heat transfer mitigation treatment thereon, preferably on an interior surface thereof."

However, tests have shown that simply metalizing the flexible panels that envelope the cellular matrix cores of the inflatable bodies referenced in WO 2009094208 A2 do not yield the degree of thermal performance improvement as expected, nor does metallization of the non-woven corrugating materials. And while substituting a metalized polymeric film having an optical density of about 1.0 for the bifurcating non-metalized film resulted in an increase of about + R-1 for the basic inflatable mattress, adding additional bifurcating metalized polymeric films having an optical density of about 2.0 only increased thermal performance by several tenths (+ R-0.6 for two films and + R-0.8 for three films).

As the above data show, progressively increasing the thickness of expanded foam cores in inflatable bodies yields a somewhat linear improvement in thermal performance, due to multiple thermal mitigation modalities inherent in expanded foam cores. However, simple "metallization" of such bodies or substantially open core inflatable bodies does not necessarily yield similar performance improvements. Moreover, the incorporation of metals and/or metalized materials into such bodies may also decrease the overall thermal performance of the inflatable body due to conduction by the metalized films and/or treated materials, and necessarily increases the weight of the inflatable body. As a consequence, the adage of "if one is good, then more must be better" does not necessarily hold true.

OBJECT OF THE INVENTION

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

SUMMARY OF THE INVENTION

In accordance with one aspect, the present invention provides an inflatable body comprising: first and second substantially opposing side panels, coupled to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a tensile structure disposed within the envelope and coupled to inner surfaces of the opposing side panels; and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to at least one of the opposing side panels to define an air-filled chamber exclusive of the tensile structure when the body is in an inflated state.

In accordance with another aspect, the present invention provides an inflatable body comprising: first and second substantially opposing side panels, coupled to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a tensile structure disposed within the envelope and having first and second tensile members separated by a planar member and coupled to inner surfaces of the opposing side panels; and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to the planar member to define an air-filled chamber exclusive of the tensile structure when the body is in an inflated state.

There is also disclosed herein an inflatable body comprising: first and second substantially opposing side panels, substantially bonded to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a cellular matrix disposed within the envelope and having at least two rows comprising hollow, open-ended geometric prisms, each defining a major axis, that establish a repeating geometric pattern and are separated by a planar member having linking locations, wherein the major axes of the prisms are generally perpendicular to the envelope periphery and wherein portions of the matrix are directly or indirectly bonded to inner surfaces of the opposing side panels at linking locations, whereby the matrix functions as tensile means for the inflatable body; and at least one means for mitigating thermal radiation transmission, the at least one means for mitigating thermal radiation transmission coupled to at least one of the opposing side panels to define an air-filled chamber exclusive of the cellular matrix when the body is in an inflated state.

There is also disclosed herein an inflatable body comprising: first and second substantially opposing side panels, substantially bonded to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a cellular matrix disposed within the envelope and having at least two rows comprising hollow, open-ended geometric prisms, each defining a major axis, that establish a repeating geometric pattern and are separated by a planar member having linking locations, wherein the major axes of the prisms are generally perpendicular to the envelope periphery and wherein portions of the matrix are directly or indirectly bonded to inner surfaces of the opposing side panels at linking locations, whereby the matrix functions as tensile means for the inflatable body; and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to the planar member to define an air-filled chamber exclusive of the cellular matrix when the body is in an inflated state.

In at least a preferred form, the present invention is directed towards inflatable bodies having improved means for mitigating thermal radiation transmission from one side of the inflatable body to an opposing side. The improved means, which broadly comprise the incorporation of at least one selectively linked and spaced apart intra-body radiant barrier, yield unexpected gains in thermal performance for inflatable bodies that otherwise might not find utility in certain environmental conditions, as will be described below.

As used herein, the generic usage of the term "inflatable body" refers to any collapsible-inflatable fluid retaining structure, whether self-inflating or not, comprising first and second sides (whether formed from discrete sheets or panels, or a single sheet or panel of material) that at least partially define a substantially fluid impermeable envelope and that are selectively linked to each other by intra-envelope tensile means (whether directly by discrete members, or indirectly by a plurality of members or a system of members), i.e., the linkage occurs within the envelope. This selective linkage of opposing sides differs from inflatable bodies having substantially coextensive linkage arrangements, such as found in prior art self-inflatable bodies that rely upon open cell foam cores that are substantially bonded to both sides, like Cascade Designs' THERM-A-REST mattresses: when inflatable body embodiments according to the invention are inflated, thereby causing the opposing sides to separate or displace from each other, the degree of separation or displacement is not uniform over the opposing sides; the non-selectively linked portions of each side are permitted to distend from virtual plane comprising the selective linkage locations. As a result, the sides have surface contours or protrusions where one side is not linked to the opposing side. The first and second sides of inflatable body embodiments of the invention may be characterized as panels, each having an inner surface presenting to the envelope and an outer surface presenting to the environment.

As used herein, collapsible cellular matrix cores found in several invention embodiments comprise a plurality of generally geometrically identical cells (hollow, open-ended geometric prisms, each defining a major axis) that are formed or linked together to establish a repeating geometric pattern (a "row"), wherein the major axes of the prisms are generally perpendicular to a perimeter portion of the inflatable body and selective portions of the matrix (“linking locations”) are directly or indirectly bonded to inner surfaces of opposing panels, whereby the matrix functions as the tensile means for the inflatable body.

In many invention embodiments, a plurality of substantially triangular hollow, open-ended prisms comprises the cellular matrix, wherein at least each of some prisms, but not all prisms, are defined by two portions of a corrugating film or thin sheet material such as a spun or non-woven filament batting and one portion of a generally planar film or thin sheet material such as a spun or non-woven filament batting. Thus, outer rows of the matrix generally comprise triangular prisms alternating with open spaces that resemble “V” shaped channels. In other words, visually, the result is WWWWW for an arbitrary outer row. Prior to the instant invention, the opposing panels that form the envelope for the inflatable body would cap or close the “V” shaped channels, thereby constituting a third wall for substantially each of the other prisms in an outer row, when the outer facing apexes, which constitute linking locations, were bonded thereto.

Turning then to a first series of invention embodiments, an inflatable body comprising a cellular matrix of the type referenced herein is augmented with at least one means for mitigating thermal radiation transmission, as herein described. The radiant barrier means of the various embodiments forming the several groups within this series comprise at least one film-based, radiant barrier established intermediate the matrix and an otherwise adjacent inflatable body panel. Each such intermediate radiant barrier preferably has greater radiant energy reflectivity than any other conventional component of the inflatable body, i.e., non-specialized or non-metalized component.

Because of this intermediate position between the cellular matrix and the panel, the intermediate radiant barrier (or in the case of plural intermediate radiant barriers, the inner most barrier) functions to establish the third wall of at least some triangular hollow, open-ended prisms as opposed to the adjacent or proximate panel, as the case may be, in conventional cellular matrix based inflatable bodies. Nevertheless, the registry between the cellular matrix linking locations and the panel linking locations remains the same.

While the following descriptions of various invention embodiments within this series establish preferred spatial relationships between the intermediate radiant barrier(s) and the otherwise adjacent panel, the actual means for mitigating thermal radiation transmission only requires the consequential result of such spatial relationships, namely, the creation of an actual or potential space or void between the barrier(s) and the panel upon inflation of the inflatable body. Therefore, the distance in at least one direction between adjacent linking locations on an intermediate radiant barrier maybe the as the distance between corresponding linking locations on the otherwise adjacent panel if a space or void between the panel and the intermediate radiant barrier can result after inflation of the inflatable body. Such a result may occur depending upon distortion of the cellular matrix upon inflation and/or differences between the mechanical properties of the matrix and the panel, as well as gravitational orientation.

With the preceding caveat in mind, a first group of invention embodiments within this series comprise a single intermediate radiant barrier established between the cellular matrix and an adjacent body panel wherein the distance in at least one direction between adjacent linking locations on the intermediate radiant barrier is less than the distance between corresponding linking locations on the panel. As a consequence of this arrangement, when the inflatable body is inflated, the intermediate radiant barrier is brought taught and the panel is urged and permitted to distend from the virtual plane comprising the linking locations, thereby forming a space or void between itself and the intermediate radiant barrier. Because this relative displacement results from inflation of the body, the space or void formation is independent of spatial orientation. In other words, the one body panel can be arbitrarily the upper or lower panel of an inflatable body such as a mattress. Additionally, such flexibility lends itself to application of an intermediate radiant barrier at each matrix-to-panel interface of the inflatable body.

An alternative to the foregoing embodiment has the distance in at least one direction between adjacent linking locations on the intermediate radiant barrier greater than the distance between corresponding linking locations on the panel. As a consequence of this arrangement, when the panel is brought taught such as by inflation of the inflatable body, the intermediate radiant barrier remains slack and is at least partially displaceable or separable from the adjacent panel, to thereby form a space or void there between. However, the space or void formation ability of this alternative arrangement is more dependent upon spatial orientation insofar as gravity may have a material effect thereon.

When a metalized polymeric film having an optical density of about 1.0 comprises the means for mitigating thermal radiation transmission in these first series embodiments, tests have shown an increase in thermal performance of the inflatable body of about + R-1. When this arrangement is duplicated on an opposing side of the inflatable body, and additional gain of about + R-1 was realized. An added benefit of these arrangements is the establishment of additional body compartmentalization, which further mitigates heat transfer due to convection.

In a second group of invention embodiments within this series, a plurality of intermediate radiant barriers are established between the cellular matrix and one body panel. Extending upon either of the embodiments referenced above, each additional intermediate radiant barrier is established inwardly (toward the cellular matrix) of a previous intermediate radiant barrier wherein the distance between adjacent linking locations in same direction as considered in the previous intermediate radiant barrier is less than (or in the alternative greater than) the distance between corresponding linking locations on the previous intermediate radiant barrier. As a consequence of this arrangement and in the first instance, when the inner most intermediate radiant barrier (the one directly linked to the cellular matrix) is brought taught, such as by inflation of the inflatable body, the panel is urged and permitted to distend from the virtual plane comprising the linking locations, thereby forming a space or void between itself and the intermediate radiant barriers. Those intermediate radiant barriers between the inner most radiant barrier and the panel are then at least partially displaceable or separable from both the inner most radiant barrier and the panel. A similar outcome results from inflation of an embodiment according to the alternative referenced above.

In addition to the increased compartmentalization of the inflatable body comprising these second group arrangements, which as previously discussed mitigates heat transfer due to convection, the creation of a space or void between adjacent intermediate radiant barrier films materially reduces heat transfer that would otherwise occur due to conduction and/or micro-convection. This finding, it is believed, at least partially explains the progressively diminishing thermal performance values when simply increasing the “metallization” of an inflatable body.

In a second series of invention embodiments, a cellular matrix of the type referenced herein for use with an inflatable body is augmented with at least one means for mitigating thermal radiation transmission, as herein described. The radiant barrier means of the various embodiments within this series comprise at least one film-based, radiant barrier established intermediate two rows of triangular hollow, open-ended prisms that form part of the cellular matrix. As with the first group of the first series, the first group of this second series seeks to establish an additional element to the inflatable body as opposed to replacing and/or enhancing an existing element. Therefore, the present thermal radiation mitigation means, which is preferably a film-based radiant barrier, is established between an existing generally planar film or thin sheet material such as a spun or non-woven filament batting, itself intermediate the two rows of prism, and an otherwise adjacent row of prisms. Also as with the first group of the first series, this radiant barrier functions to establish the third wall of at least some triangular hollow, open-ended prisms, but instead with respect to the existing substantially planar film or sheet. As a consequence, no prism in one row shares a common enclosing wall with any prism in an adjacent row.

Because there are no common enclosing walls between rows of prisms, it is possible, and considered preferable, to establish a space or void between these two intra-row elements, particularly if the existing substantially planar film or sheet itself can be characterized as mitigating thermal radiation transmission. Thus, the distance in at least one direction between adjacent linking locations on the intermediate radiant barrier is preferably less than, but can also be greater than, the distance between corresponding linking locations on the existing substantially planar film or sheet. If the existing substantially planar film or sheet is best characterized as a non-film, then equivalent distances are considered within the scope of the invention due to the different mechanical properties between the two materials.

Finally, a third series of invention embodiments combines arrangements from the first two, and represents a presently preferred embodiment. In particular, an inflatable body according to this series has a cellular matrix with radiant barrier means for mitigating thermal radiation transmission intermediate the cellular matrix and both opposing panels as well as intermediate two rows of triangular hollow, open-ended prisms. Test have shown that inflatable bodies having a thickness of about 2.5" (-6.25 cm) and comprising these modifications have thermal insulation values of about R-4.9. For comparison, a conventional inflatable mattress having a 2" (-5.0 cm) thick piece of 0.9 density open cell polyurethane foam has a comparable "FT value, but weights almost five times more and, when manually compressed for storage, displaces about four times the volume. If the existing generally planar film or thin sheet material can be characterized as having thermal radiation transmission mitigation properties the same as or similar to that of the intermediate radiant barrier, then the thermal insulation value increases to about Ft-5.7.

The inflatable bodies described and shown herein are not limited to camping mattresses, but may find utility in any application that can utilize many of its key properties: thermal management, compact storage, ease of deployment (inflatable), light weight and structural stability. Potential uses such as portable structures or tents, seating ,window shades, thermally insulated boxes or containers, water cooling and heating systems, cold-weather clothing, sleeping bags and systems, and shock or impact attenuation systems.

For purposes of this patent, the terms "area", "boundary", "part", "portion", "surface", "zone", and their synonyms, equivalents and plural forms, as may be used herein and by way of example, are intended to provide descriptive references or landmarks with respect to the article and/or process being described. These and similar or equivalent terms are not intended, nor should be inferred, to delimit or define per se elements of the referenced article and/or process, unless specifically stated as such or facially clear from the several drawings and/or the context in which the term(s) is/are used.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:

Fig. 1 is a perspective view a prior art inflatable body having tensile means in the form of a cellular matrix, wherein opposing panels form a plurality of the triangular, hollow open-ended prisms that comprise the matrix;

Fig. 2 is a perspective view a first series embodiment of an inflatable body according to the invention wherein an intermediate radiant barrier is established between the cellular matrix and one panel;

Fig. 3 is a perspective view a derivative of the embodiment of Fig. 2, wherein a second intermediate radiant barrier is established between the cellular matrix and an opposing panel; and

Fig. 4 is a perspective view a derivative of the embodiment of Fig. 3, which incorporates aspects of a second series embodiment according to the invention, wherein a third intermediate radiant barrier is established between rows of prisms within the cellular matrix.

DESCRIPTION OF INVENTION EMBODIMENTS

Preface: The terminal end of any numeric lead line in the several drawings, when associated with any structure or process, reference or landmark described in this section, is intended to representatively identify and associate such structure or process, reference or landmark with respect to the written description of such object or process. It is not intended, nor should be inferred, to delimit or define perse boundaries of the referenced object or process, unless specifically stated as such or facially clear from the drawings and the context in which the term(s) is/are used. Unless specifically stated as such or facially clear from the several drawings and the context in which the term(s) is/are used, all words and visual aids should be given their common commercial and/or scientific meaning consistent with the context of the disclosure herein.

With the foregoing in mind, the following description is presented to enable a person skilled in the art to make and use the claimed invention. Various modifications to the described embodiments will be readily apparent to those skilled in the art, and the generic principles disclosed herein may be applied to other embodiments and applications thereof without departing from the spirit and scope of the present invention, as defined by the appended claims. Thus, the claimed invention is not intended to nor should be limited to the disclosed and/or described embodiments, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Turning then to the several embodiments, wherein like numerals indicate like parts, and more particularly to Figs. 1, prior art inflatable mattress 10 is shown having outer panels 20a and 20b, planar or bifurcating member 30 and corrugating or serpentine members 40a and 40b. Together, these components form prisms 50, which in the aggregate, create rows I and II. Each prism 50 further includes three linking locations, alternately two for linking with a panel 20a or 20b and one for linking with member 30, or one for linking with a panel 20a or 20b and two for linking with member 30. These linking locations correspond to complementary linking locations on the noted panels and member.

Figure 2 shows a modified version of mattress 10 according to one aspect of the invention. Modified mattress 100 includes intermediate radiant barrier 60b, which is established between row II and panel 20b. As illustrated, the distance between linking locations of panel 20b is greater than the distance between linking locations of radiant barrier 60b, thereby forming spaces or voids 70b.

Figure 3 further modifies mattress 100 according to another aspect of the invention. Modified mattress 200 includes intermediate radiant barrier 60a, which is established between row I and panel 20a. As illustrated, the distance between linking locations of panel 20a is greater than the distance between linking locations of radiant barrier 60a, thereby forming spaces or voids 70a.

Finally, Fig. 4 further modifies mattress 200 according to another aspect of the invention. Modified mattress 300 includes intermediate radiant barrier 60c, which is established between planar or bifurcating member 30 and corrugating or serpentine members 40a of row I. As illustrated, the distance between linking locations of planar or bifurcating member 30 is less than the distance between linking locations of radiant barrier 60c, thereby forming spaces or voids 70c.

Claims

1. An inflatable body comprising: first and second substantially opposing side panels, coupled to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a tensile structure disposed within the envelope and coupled to inner surfaces of the opposing side panels; and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to at least one of the opposing side panels to define an air-filled chamber exclusive of the tensile structure when the body is in an inflated state.

2. The inflatable body of claim 1, wherein the at least one thermal radiation transmission mitigation element comprises a single intermediate radiant barrier established between the tensile structure and an adjacent side panel.

3. The inflatable body of claim 1, wherein the at least one thermal radiation transmission mitigation element comprises a first intermediate radiant barrier established between the tensile structure and a first adjacent side panel and a second intermediate radiant barrier established between the tensile structure and a second adjacent side panel.

4. The inflatable body of claim 3, wherein the first and the second side panels are in opposition.

5. The inflatable body of any one of claims 1, 2 or 3, wherein a distance between linking locations at which the tensile structure is coupled to a side panel are different from a distance between linking locations at which the tensile structure is coupled to an intermediate radiant barrier, when the inflatable body is in an inflated state.

6. The inflatable body of claim 1, wherein the at least one thermal radiation transmission mitigation element comprises a single intermediate radiant barrier established within the tensile structure.

7. The inflatable body of claim 6, wherein the single intermediate radiant barrier selectively forms a portion of the tensile structure.

8. The inflatable body of claim 6 or 7, wherein a distance between linking locations at which the tensile structure is coupled to a planar member is different than a distance between linking locations at which the tensile structure is coupled to the single intermediate radiant barrier.

9. An inflatable body comprising: first and second substantially opposing side panels, coupled to each other about a common periphery to at least partially define a substantially fluid impermeable envelope; a tensile structure disposed within the envelope and having first and second tensile members separated by a planar member and coupled to inner surfaces of the opposing side panels; and at least one thermal radiation transmission mitigation element, the at least one mitigation element directly coupled to the planar member to define an air-filled chamber exclusive of the tensile structure when the body is in an inflated state.

10. The inflatable body of claim 9, wherein the at least one thermal radiation transmission mitigation element comprises a single intermediate radiant barrier established between the tensile structure and an adjacent side panel.

11. The inflatable body of claim 9, wherein the at least one thermal radiation transmission mitigation element comprises a first intermediate radiant barrier established between the tensile structure and a first adjacent side panel and a second intermediate radiant barrier established between the tensile structure and a second adjacent side panel.

12. The inflatable body of claim 11, wherein the first and the second side panels are in opposition.

13. The inflatable body of claim 9, wherein the at least one thermal radiation transmission mitigation element comprises a single intermediate radiant barrier established within the tensile structure.

14. The inflatable body of claim 10, wherein the single intermediate radiant barrier selectively forms a portion of the tensile structure.