Abstract:
A mattress wherein a plurality of independent yarn based fire barrier fabrics encases a plurality of distinct and unattached interior core structures. The plurality of interior core structures include at least a detached and internally flippable upper comfort layer assembly with a plurality of non-homogeneous foams or filling materials encased in a yarn-based fire barrier fabric and a lower, interiorly disposed support core structure with resilient filling materials encased in a yarn-based fire barrier fabric and a fabric cover. The detachable and internally flippable upper comfort layer assembly may be contained in a user accessible compartment that is fashioned into an outer cover assembly.

Description:
RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 13/623,486, filed Sep. 20, 2012, the entire contents of which are incorporated in their entirety herein by reference 
    
    
     BACKGROUND 
     The design, manufacture, and assembly of mattresses, mattress foundations, upholstered furniture articles and other articles filled with resilient cushioning materials has varied little in the history of these products. The primary areas of innovation have occurred with the introduction of new filling materials. 
     According to the International Sleep Products Association (ISPA), the domestic US mattress industry shipped mattresses and foundation units in 2010 totaling 34 million units or roughly 17 million sets of bedding with a retail value in excess of $11 billion. 
     Numerous filling materials are used to construct mattresses, mattress foundations, upholstered furniture articles and other articles filled with resilient cushioning materials. These can be made from, for example, foam, fiber or other similar resilient material. 
     Manufacturers of flexible polyurethane foam, textile fibers, and other resilient filling materials employ a wide variety of technical measurements to communicate the performance attributes engineered into particular foams. Such technical measurements include indentation force deflection (IFD), indentation load deflection (ILD), tensile strength, tear strength, density pounds per cubic foot (PCF), flex fatigue, denier, cut length, and basis weight. 
     Materials may be further differentiated by their composition. In the case of flexible polyurethane foams, for instance, there are visco-elastic foams, latex foams, gel-infused foams, memory foams, conventional foams, filled conventional foams, high resiliency (HR) foams, modified HR foams, combustion modified foams, melamine modified foams—all of which can be made at differing densities and hardnesses making the possible total number of combinations potentially limitless. 
     It is well known that flexible foam materials have demonstrably different levels of flame retardance. For instance, latex foam is highly flammable and therefore, presents a much more difficult fuel load to protect from open flame ignition sources than that of the fuel load of a standard polyurethane foam. The need for protection based on foam type impacts the manufacturers&#39; selection of fire barrier materials. 
     During the last several years, U.S. mattress manufacturers have manufactured “one-sided” mattresses. 
     Using marketing that intimates that this is preferable to the consumer as they no longer have to “flip” their mattress, the fact is that the manufacture of a “one-sided”, “non-flippable” mattress is both a sales growth and cost saving effort by manufacturers. It is a sales growth effort in that a two-sided mattress could reasonably be expected to have twice the useful life expectancy of the current one-sided units, so shortening the life span results in increase purchase frequency by consumers—a potential sales doubler. The cost cutting aspect is a result of removing the costly comfort delivering fillings on one-side of the mattress. Not surprisingly, retail price points for mattresses did not decline commensurately to reflect the life shortening and cost reductions when this product change occurred. 
     Much of the growth of one-sided mattresses began with the AB 603 mattress flammability standard in California and later reached near universal design adoption that coincided with the implementation of the Federal Mattress Flammability Standard 16 CFR 1633 in 2007. Many mattress manufacturers determined that typical, tape-edged and two-sided mattresses had a crown or convex surface profile on the panel planar surface of the mattress that when placed on a flat foundation structure created a crevice between mattress and foundation that present testing challenges. Removing one convex side from the mattress design eliminated the crevice and facilitated testing compliance. 
     The design evolution of mattresses away from two-sided constructions and toward one-sided constructions has several, potentially adverse implications for consumers that have not been effectively addressed by manufacturers. 
     The resilient cushioning materials used by mattress manufacturers to create the sleeping surface of the mattress and to afford the user a level of comfort while sleeping are prone to physical breakdown during use. This is referred to as “taking a set” and the mattress industry itself describes the presence of these body impressions as “normal”. Over time, these body impressions do degrade the sleep experience and the benefits sought to be derived from the sleep experience. In a two-sided mattress, users were instructed to flip and rotate the mattress every several months to balance the occurrence of the impressions—in a traditionally designed one-sided, no-flippable mattress, this option to promote longevity is reduced. In fact, current marketing of mattresses touts the lack of “maintenance” required for one-sided mattresses. 
     Second, the traditional approach to mattress design has been to construct the product in such a manner as to preclude the end-user from being able to access interior components of the mattress. As the cushioning materials physically breakdown, the end-user is left with no alternative but to replace the entire mattress assembly in order to rectify the body impressions condition. Given that conventional end-of-life-cycle disposal of mattresses has been to place them in landfills, the increasing pace at which the one-sided mattress design can be expected to result in disposal and replacement, the potential waste-stream impact of the one-sided mattress in potentially substantial. 
     While the retail mattress world has been flocking to the one-sided mattress design, one arena where two-sided mattresses still find wide acceptance is in college dormitory environments. Since institutional purchasers, such as college and university residence life operations, view residence hall mattresses as an asset whose value is enhanced with longer service life, the ability to flip mattresses with a two-sided traditional mattress design has remained desirable. 
     Some two-sided institutional mattress designs promote the benefit of a dual firmness design, wherein the filling materials selected for one of the two sides is chosen to be “soft” and the other side&#39;s materials are chosen to be “firm”, thereby permitting the end-user to custom select their preferred sleep surface. 
     The invention captures the benefits of both the one-sided design and the dual-firmness design approach of certain two-sided mattresses simultaneously, and does so in a manner that can afford environmentally conscious end-users with the ability to reduce the waste stream impact of disposal of mattresses when filling materials degrade after their useful life expectancy. Since the upper comfort layer assembly is accessible to the end-user, the foam or filling materials may be replaced when, through the normal course of use or in the event of damage, the end-user wishes. The ability to replace only the upper comfort layer foam or filling materials and the fire barrier that encases them, while preserving for use the remaining mattress components results in a lessened disposal impact. Additionally, the detachable cover assembly itself may be replaced if worn or soiled, again permitting the preservation of the remaining, still serviceable mattress components and lessening the disposal impact. 
     The invention further delivers the benefit of material design flexibility as it relates to fire barrier selection, especially in the case of knitted, tubular fire barriers, to meet requirements of full-scale fire testing, such as 16 CFR 1633. Heretofore, conventional mattress design approaches have elected to substantially encase the entire mattress structure in fire barrier material capable of addressing the worst-case flammability profile of components or filling materials selected for construction of the mattress. For instance, if a mattress design used a combination of highly flammable materials, such as latex foam, in conjunction with materials that were less flammable, such as standard polyurethane foam or foams that are moderately combustion modified, then the barrier would likely have to be chosen from a more robust, therefore heavier and more expensive fire barrier design that could address the flammability profile of the worst-case component—in this case latex foam. The invention, through its use of a plurality of fire barriers, provides the potential to tailor the fire barrier selection to each specific region of the mattress and its associated propensity to ignite when exposed to an open-flame ignition source, and therefore achieve material efficiencies not afforded by pre-existing design approaches. The use of a plurality of independent fire barrier systems allows the flexibility of design that enables the targeted selection fire barriers to address the specific and potentially disparate flammability characteristics for various elements of the present invention 
     BRIEF SUMMARY 
     The invention provides for an improved mattress that may be sold alone to an end-consumer or in a set of bedding with a traditional foundation. 
     In one embodiment, a mattress is formed from a lower, interiorly disposed support core structure and detachable cover assembly. The lower, interiorly disposed support core structure is constructed of a foam encased innerspring unit that is encased entirely by a yarn-based knitted fire barrier fabric or sock. The fire barrier encased core assembly is then enclosed in a fabric cover that is sewn closed. The detachable and internally flippable upper comfort layer assembly is contained in a user accessible compartment that is fashioned into an outer cover assembly which is tailored to also encase the lower, interiorly disposed support core structure. The detachable and internally flippable upper comfort layer assembly is comprised of a plurality of non-homogeneous foams or filling materials and is itself partially or fully encased in a yarn-based knitted fire barrier fabric or sock. According to the instant invention, the fire barrier fabrics or socks used to independently encase the lower, interiorly disposed support core structure and the upper comfort layer assembly may be identical. However, the disparate flammability resistance properties expected from the use of non-homogeneous foams or resilient filling materials will likely dictate the use of fire barrier fabrics or socks which have differing degrees of flame resistant properties. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in conjunction with the following drawing in which like reference numerals designate like elements and wherein: 
         FIG. 1  is a cross-sectional view providing an overview of the mattress construction, which shows a lower, interiorly disposed support core structure, a removable cover system, and an upper comfort layer core assembly. 
         FIG. 2  is a cross-sectional, detailed view of the lower, interiorly disposed support core structure. 
         FIG. 3  is a cross-sectional, detailed view of the removable cover system. 
         FIG. 4  is a cross-sectional, detailed view of the upper comfort layer core assembly. 
         FIG. 5  is a cross-sectional, detailed view of the finished mattress according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments of the invention will be described and illustrated in detail, however, it will be apparent to those of skill in the art that other embodiments of the invention are realizable and that the embodiments illustrated and described herein are not meant to limit the scope of the invention. 
     A mattress and terms relating to mattresses are defined below and conform to the terms as defined by 16 C.F.R. 1632, the entire contents of which are incorporated herein by reference. Additionally, the terms defined below conform to the terms as defined in the NPR on Mattress Flammability of 16 CFR 1633 as approved by the CPSC on Feb. 16, 2006, the entire contents of which are incorporated herein by reference. 
     A mattress refers to a ticking filled with a resilient material used alone or in combination with other products intended or promoted for sleeping upon. Examples include but are not limited to adult mattresses; youth mattresses; crib mattresses such as portable crib mattresses; bunk bed mattresses; futons; water bed; air mattresses which have upholstery material between the ticking and the mattress core; and any detachable mattresses used in any item of upholstered furniture such as convertible sofa bed mattresses, corner group mattresses, day bed mattresses, roll-a-way bed mattresses, high risers, and trundle bed mattresses. A mattress may also be called a bed. 
     For purposes of this disclosure, a mattress does not include sleeping bags; pillows; mattress foundations; liquid and gaseous filled tickings such as water beds and air mattresses which do not have upholstery material between the ticking and the mattress core; upholstered furniture which does not have a detachable mattress such as chaise lounges, drop-arm love seats, press-back lounges, push-back sofas, sleep lounges, sofa beds (including jackknife sofa beds), sofa lounges (including glide-outs), studio couches and studio divans (including twin studio divans and studio beds); and juvenile product pads such as car bed pads, carriage pads, basket pads, infant carrier and lounge pads, dressing table pads, stroller pads, crib bumpers, and playpen pads. 
     A mattress pad refers to a thin, flat mat or cushion, and/or ticking filled with resilient material for use on top of a mattress. Examples include, but are not limited to, absorbent mattress pads, flat decubitus pads, and convoluted foam pads, which are totally enclosed in ticking. For purposes of this disclosure, a mattress pad does not include foam pads, which are not totally encased in ticking. 
     Ticking refers to the outermost layer of fabric or related material that encloses the core and upholstery materials of a mattress or mattress pad. A mattress ticking may include, for example, several layers of fabric or related materials quilted together. 
     Core refers to the main support system that may be present in a mattress, such as springs, foam, hair block, water bladder, air bladder, or resilient filling. For purposes or this disclosure, a mattress may have a plurality of core structures. 
     Upholstery material refers to all material, either loose or attached, between the mattress or mattress pad ticking and the core of a mattress, if a core is present. 
     Tape edge (edge) refers to seam or border edge of a mattress or mattress pad. 
     Quilted refers to stitched with thread or by fusion through the ticking, and one or more layers of upholstery material. 
     Tufted refers to buttoned or laced through the ticking and upholstery material and/or core, or having the ticking and upholstery material and/or core drawn together at intervals by any other method which produces a series of depressions on the surface. 
     A mattress foundation is any surface such as foam, box springs or other, upon which a mattress is placed to lend it support for use in sleeping upon. 
     An article of upholstered furniture is a resilient filling material that may optionally be supported by a frame or structure and is encased by a textile structure. The article of upholstered furniture is intended to be used for sitting or reclining but is not primarily intended for sleeping and conforms to the term as defined by the draft language of 16 C.F.R. 1634, as published by the CPSC in May 2005, the entire contents of which are incorporated herein by reference. 
     A textile structure is any type of material made from fibers or other extended linear materials such as thread or yarn. Classes of textile structures include woven fabrics, knitted fabrics, crocheted fabrics, knotted or tufted cloth and non-woven fabrics, such as felt, high loft, spunlaced, stitch-bonded, hydroentangled, air laid or needle punched fabrics. A textile structure also encompasses composites of multiple textile structures that may include the foregoing textile classes. 
       FIG. 1  is an illustration in the form of a cross-sectional view of a mattress assembly  10  of an embodiment of the invention with a lower, interiorly disposed support core structure  20 , a detachable cover assembly  30  and an upper comfort layer core assembly  40 . 
       FIG. 2  is an illustration in the form of a cross-sectional view of the lower, interiorly disposed support core structure  20 . Measurements provided are for reference and are not intended to be limiting in the present invention as it is contemplated that measurements of selected materials may be adjusted to meet construction requirements or material costing requirements. An embodiment of the lower, interiorly disposed support core structure  20  for a twin-sized mattress illustrated in  FIG. 2  includes the following: 
     A base slab of polyurethane foam  21  measuring approximately 38″ wide by 74″ long by 1½″ thick. The selected foam may be standard polyurethane foam with a 1.8 density and an ILD of between 25 and 45. 
     Side rails  22  measuring approximately 68″ long by 1½″ wide by 4″ tall and head/foot rails  23  measuring approximately 38″ long by 3″ wide by 4″ tall affixed, e.g., glued, to the slab  21  and to each other at the corners to create a foam encasement cavity structure with one open side. Standard polyurethane foam with a 1.8 pound density and an ILD of greater than 40 may be used. The type of glue used or the possible selection of alternative methods of attaching the foam pieces  21 ,  22 , and  23  to one another is not limited by the invention. 
     A non-woven textile  24  measuring approximately 35″ wide by 68″ long may be provided inside the foam encasement cavity structure, in contact with the exposed face of slab  21 . Textile  24  mitigates or prevents penetration of the foam encasement surface, especially base slab  21  or lid  27 , by the innerspring unit that is installed inside the foam encasement cavity structure in this embodiment. Alternatively, a pad made of recycled textile and foam remnants known as a “shoddy” pad may be used; however the omission of this textile  24  or alternatives is contemplated by the invention. 
     An innerspring assembly  25  of conventional design measuring approximately 35″ wide by 68″ long and 4″ tall may be provided inside the foam encasement cavity structure and atop the textile  24 . The particular design of the innerspring is not a limiting feature of the invention and it is fully contemplated that the use of unconventional innerspring designs or even the omission of the innerspring entirely and its replacement with alternative filling materials that occupy the cavity of the foam encasement structure fall within the scope of the invention. 
     A non-woven textile  26 , similar to  24 , may be provided atop the installed innerspring assembly  25 . Textile  26  mitigates or prevents penetration of the foam encasement surface, especially base slab  21  or lid  27 , by the innerspring unit that is installed inside the foam encasement cavity structure in this embodiment of the invention. Alternatively, a pad made of recycled textile and foam remnants known as a “shoddy” pad may be used; however the omission of this textile  24  or alternatives is contemplated by the invention. 
     A lid  27  or base slab  21  of polyurethane foam measuring approximately 38″ wide by 74″ long by 1½″ thick may be affixed, e.g., glued to top surfaces of side rails  22  and head/foot rails  23 . The selected foam may be standard polyurethane foam with a 1.8 density and an ILD of between 25 and 45. The type of glue used and alternative methods of attaching the foam pieces  27 ,  22  and  23  to one another is not limited by the invention. 
     The lid  27  or slab  21  is affixed, e.g., glued, onto the foam encasement cavity structure, which completes the formation of a foam encased innerspring. However, a core completely comprised of foam, for instance a foam block measuring approximately 38″ wide by 74″ long by 7″ thick, is an alternative embodiment that is contemplated by the invention. 
     A knitted, tubular, yarn-based fire barrier  28 , specifically, I30® Barrier Style 5041 as sold by Ventex, Inc. of Great Falls Va., may be cut to fit the block and then sewn closed at one end with Kevlar® thread, pulled over the foam core block and sewn closed at the opposite end with Kevlar® thread. This particular fire barrier  28  may be comprised of fiberglass and flame retardant rayon fibers, however the invention fully contemplates the use of alternative fibers and yarns to fabricate the fire barrier, including the following: aramids, including para-aramids (poly(p-phenylene terephthalamide), e.g., KEVLAR®. (Dupont Corporation) and TWARON® (Teijin Twaron, BV) and meta-aramids (poly(m-phenylene isophthalamide), such as Nomex® (Dupont Corporation); fiberglass; melamines such as BASOFIL® (BASF); poly-benzimidazole (PBI) (Celanese Acetate A.G); oxidized polyacrylonitrile (PAN); novoloids, such as KYNOL® (American Kynol, Inc); pre-oxidized fibers and carbon fibers, modacrylics, such as, e.g., KANECERON®. and PROTEX® (Kaneka), FR (fire- or flame-resisting, -resistant, -retarding or -retardant) rayon, FR viscose, such as, e.g., LENZING FR® (Lenzing AG, Fibers Division) and VERIFIBER® TCF FR Rayon Fiber (Ventex, Inc.), wool and FR-treated cotton. It should be noted that these fibers are merely exemplary, and other fire-retardant fibers may be used. 
     Additionally, certain proprietary modacrylic fibers that release extinguishing/oxygen depriving elements such as antimony when exposed to an ignition source may be used. This chemical reaction may assist in snuffing out small flames that may occur on adjacent, non-FR components such as the mattress covering fabric or ticking. Blends that include at least one fire-retardant fiber that form a char may also be used. The blends may include one or more structure-providing char-forming fire-retardant fibers, FR-treated fibers, such as FR-treated polyester, and non-FR fibers. Non-flame-resistant polyester may be used as a carrier fiber for manufacturing fiberglass fabrics, and these fabrics may have 10% of a polyester fiber, and up to 50% of that fiber. Furthermore, while preference is given to use of inherently flame retardant yarns and fibers in the fabrication of the yarn-based fire barrier  28 , the use of chemical treatments to achieve flame retardant performance is fully contemplated. 
     Following the closure of the fire barrier sleeve or sock  28 , a cover assembly  29  may be provided to fully enclose and complete the lower, interiorly disposed support core structure  20 . In this embodiment, the fabric may be a polyurethane coated nylon fabric sold as SOFlux OX-V® HF (Ventex, Inc.). This cover assembly is sewn closed, however the use of sealable fabrics is fully anticipated in this invention. Furthermore, the selection of fabric used to fashion the cover assembly  29  is open to the design requirements of the finished mattress and its intended use profile. The broadest selection of fluid and pest (including, but not limited to bed bugs, dust mites, or lice) impervious fabrics is contemplated, as is the use of anti-microbial, anti-fungal or anti-bacterial finishes and treatments on the fabric. Alternative embodiments are contemplated that do not utilize fabrics for cover assembly  29  with fluid resistant properties or material impervious finishes, however the omission of such features would reduce potential benefits contemplated by the invention. 
     Contemplated and executed alternative embodiments to the instant invention used a fabric cover assembly  29  made from Recovery5™ Healthcare Fabric (Ventex, Inc.), a fluid resistant and heat-sealable fabric, made from a polyurethane film that is transfer coated or laminated to a knitted polyester substrate. The cover may be heat sealed to create a cover that is impervious to fluid ingress or bed bug ingress into the lower, interiorly disposed support core structure  20 . 
       FIG. 3  is an illustration in the form of a cross-sectional representation of the detachable cover assembly  30  according to a second embodiment of the invention. By way of example, the detachable cover assembly  30  for a twin-sized mattress may be constructed as follows: 
     A knitted, fabric ticking  31  Nuvola™ Halogen Free Style CT0806 (Creative Ticking, LLC) may be used to create an upper compartment  32  to house the upper comfort layer core assembly (not shown in this figure). 
     The upper compartment  32  may be completed by joining the interior textile  35 , a stitch bonded, TCF Rayon Filler Cloth  35 , to the ticking  31  by means of a zipper  34  that transits the entire perimeter of the seam between the two materials. The zipper  34  may be internally disposed to the construction of the detachable fabric cover  30 , and as such would not be visible to the outside of the mattress  10  assembly. In this embodiment, the zipper  34  joins the interior textile  35  along the entire interior perimeter of the planar surface of the mattress; however the joining of the ticking  31  to interior textile  35  may be accomplished with a combination of a zipper or similar closing system and sewn seams. Note, the zipper, seams or any other joining areas between the ticking  31  and interior textile  35  are located inside the cover and are not be visible from the outside of the cover. 
     An additional section of fabric ticking  31  may be provided to descend vertically along the border of the mattress from the lower, outside visible seam line of the upper compartment  32  and create the lower compartment  33  that houses the lower, interiorly disposed support core structure (not shown in this figure) and is joined to the non-slip bottom fabric  37  of the cover assembly  30 . The non-slip bottom fabric  37  may be joined to the fabric ticking  31  of the lower compartment  33  by means of a zipper  36 . The zipper  36  may be disposed outside the detachable fabric cover  30 , and as such would be visible to the outside of the mattress  10  assembly. However, the zipper  36  is preferably provided on the planar face of the mattress that rests atop the mattress foundation or other similar support structure. In this embodiment, the zipper  36  joins the non-slip bottom fabric  37  along the entire interior perimeter of the lower planar surface of the mattress; however the joining of the ticking  31  to the non-slip bottom fabric  37  may be accomplished by a combination of a zipper or similar closing system and sewn seams. Note, the zipper, seams, or any other joining areas between the ticking  31  and the non-slip bottom fabric  37  are located inside of the cover and are not necessarily visible from the outside of the cover. 
       FIG. 4  is an illustration in the form of a cross-sectional representation of the upper comfort layer core assembly  40  according to an embodiment of the invention. By way of example, the upper comfort layer core assembly for a twin-sized mattress may be constructed as follows: 
     A first comfort layer slab of foam  41  measuring 38″×74″×2″ is provided. The foam  41  may be selected from latex rubber foam with a density of greater than 4.0 pounds and an ILD of between 10 and 25 and an LOI of less than 30. 
     A second comfort layer slab of foam  42  measuring 38″×74″×2″ is provided. The second piece of foam  42  may be selected from standard polyurethane foam with a density of 1.8 pounds and an ILD of 30 and an LOI of less than 30. 
     The first comfort layer slab of foam  41  and the second comfort layer slab of foam  42  are glued together along the planar faces of the two slabs. For purposes communicating the benefits of the invention clearly, only two pieces of foam are used in the detailed description herein; however it is contemplated that more than two non-homogeneous types of foam or other resilient filling materials could be employed in alternative embodiments. 
     The joined pieces of foam  41  and  42  are then encapsulated in a knitted, tubular, yarn-based fire barrier  43 , specifically, K1™ Barrier Style 6377, a halogen-free, para-armid based fire barrier as sold by Ventex, Inc. of Great Falls Va., which is cut to fit the block and then sewn closed at one end with Kevlar® thread, pulled over the foam core block and sewn closed at the opposite end with Kevlar® thread. This particular fire barrier  43  is comprised of para-aramid fiber and flame retardant rayon fibers, however the invention fully contemplates the use of alternative fibers and yarns to fabricate the fire barrier, including the following: aramids, including para-aramids (poly(p-phenylene terephthalamide), e.g., KEVLAR®. (Dupont Corporation) and TWARON® (Teijin Twaron, BV) and meta-aramids (poly(m-phenylene isophthalamide), such as Nomex® (Dupont Corporation); fiberglass; melamines such as BASOFIL® (BASF); poly-benzimidazole (PBI) (Celanese Acetate A.G); oxidized polyacrylonitrile (PAN); novoloids, such as KYNOL® (American Kynol, Inc); pre-oxidized fibers and carbon fibers, modacrylics, such as, e.g., KANECERON®. and PROTEX® (Kaneka), FR (fire- or flame-resisting, -resistant, -retarding or -retardant) rayon, FR viscose, such as, e.g., LENZING FR® (Lenzing AG, Fibers Division) and VERIFIBER® TCF FR Rayon Fiber (Ventex, Inc.), wool and FR-treated cotton. 
     It should be noted that these fibers are merely exemplary, and other fire-retardant fibers, including fibers that are developed in the future may be used. Additionally, certain proprietary modacrylic fibers that release extinguishing/oxygen depriving elements such as antimony when exposed to an ignition source may be used. This chemical reaction may assist in snuffing out small flames that may occur on adjacent, non-FR components such as the mattress covering fabric or ticking. Blends that include at least one fire-retardant fiber that form a char may also be used. The blends may include one or more structure-providing char-forming fire-retardant fibers, FR-treated fibers, such as FR-treated polyester, and non-FR fibers. Non-flame-resistant polyester may be used as a carrier fiber for manufacturing fiberglass fabrics, and these fabrics may have 10% of a polyester fiber, and up to 50% of that fiber. Furthermore, while preference is given to use of inherently flame retardant yarns and fibers in the fabrication of the yarn-based fire barrier  43 , the use of chemical treatments to achieve flame retardant performance is fully contemplated. 
       FIG. 5  illustrates a final assembly of the mattress according to an embodiment of the invention. By way of example, the embodiment may be constructed as follows: 
     The upper comfort layer core assembly  40  may be installed into the upper compartment  32  of the detachable cover assembly  30 , and the zipper  34  is closed. 
     The detachable cover assembly  30  may then installed over the lower, interiorly disposed support core structure  20 , and the zipper  36  is closed. 
     The finished mattress  10  may be installed atop a foundation. 
     The illustrated embodiment of the invention is for a twin sized specimen with finished exterior dimensions measuring approximately 39″ wide by 75″ long by 11″ high or thick. All other sizes of mattresses and foundations are contemplated as being able to enjoy the benefits of the invention described herein. Furthermore, it is fully contemplated that larger sized mattresses, e.g. Queen and King sized mattresses, may be fashioned from all possible combinations that would employ one or more lower, interiorly disposed support core structures  20  and one or more upper comfort layer core assemblies  40  encased in a single detachable cover assembly  30 . 
     The mattress of the invention departs significantly from the prior art. For example, the detachable nature of the cover assembly  30  and accessibility of the upper compartment  32  allows the end user to flip the upper comfort layer core assembly  40  to suit their personal preference for a sleeping surface. For instance, one criticism of some visco-elastic memory foams and latex foams is that they exhibit higher levels of heat build-up from sleeping bodies and therefore sleep “hotter” than other types of foam, whereas newer, gel-infused foams have been designed to deliver a “cooling” effect. The design flexibility in the invention permits seasonal adjustment to sleeping temperature simply through planar rotation or “internally flipping” the upper comfort layer core assembly  40 . 
     Furthermore, when the upper comfort layer core assembly  40  begins to exhibit signs of wear or “taking a set”, the end user may replace the assembly without discarding the remainder of the mattress components. 
     However, this design flexibility must comply with full-scale flammability testing. The choice of fire barrier  43  is critical to the ability of the mattress to meet the requirements of full-scale open flame fire testing. Since the invention is not limiting with regards to the particular types of foams or other filling materials that may be used in positions occupied by foam slabs  41  or  42 , it is contemplated that they could be of significantly disparate levels of flame retardance. 
     It is well-known that the selection of foam or fibrous filling materials can impact the composite article&#39;s ability to withstand an open flame ignition source and therefore comply with full-scale fire test protocols such as 16 CFR 1633, California Technical Bulletin #603 (TB603), California Technical Bulletin #129 (TB129), or Boston Fire Department IX-11 (BFDIX-11), all of which are incorporated in their entirety by reference. 
     For the purposes of the invention, it is desirable to identify the disparate propensities to ignite for such materials into a four level classification schema, such as that found in Table 1. 
     
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Classification Scheme for Degree of Flammability for Mattress Foams and 
               
               
                 Filling Materials 
               
             
          
           
               
                   
                 Relative Degree of 
                   
               
               
                 Level 
                 Expected Flammability 
                 Examples 
               
               
                   
               
               
                 A 
                 Highly flammable 
                 Latex Foam/Gel 
               
               
                 B 
                 Moderately Flammable 
                 Gel-Infused Foam, Visco-Elastic 
               
               
                   
                   
                 Memory Foam 
               
               
                 C 
                 Mildly Flammable 
                 Standard Polyurethane Foam, 
               
               
                   
                   
                 Slickened polyester fiber batting 
               
               
                 D 
                 Combustion Resistant 
                 Foams treated with Flame Retardant. 
               
               
                   
                   
                 Unslickened (dry) polyester fiber 
               
               
                   
                   
                 batting, wool, 
               
               
                   
               
             
          
         
       
     
     In order to optimize the mattress design, with respect to the selection of the fire barriers, it is important to understand the relative protective levels of the barrier or barrier system, which may typically be achieved by a review of the material or system basis weight as measured in ounces per square yard of textile material. One example of a possible classification scheme for the fire barrier selection may be found in Table 2. The appropriate selection is intended to promote the ability of the composite article to pass the required fire test. 
     
       
         
               
             
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Classification Example for Fire Barrier Selection 
               
             
          
           
               
                   
                 Relative Degree of 
                   
               
               
                 Level 
                 Flammability Protection 
                 Aggregate Basis Weight 
               
               
                   
               
             
          
           
               
                 1 
                 Highest Performing 
                 &gt;7.0 
                 oz per square yd 
               
               
                 2 
                 Strong Performing 
                 5.0 to 7.0 
                 oz per square yd 
               
               
                 3 
                 Medium Performing 
                 3.5 to 5.0 
                 oz per square yd 
               
               
                 4 
                 Minimum Performing 
                 1.0 to 3.5 
                 oz per square yd 
               
               
                   
               
             
          
         
       
     
     One methodology contemplated by the invention would be to match a fire barrier selection to a foam or filling material selection based on the relative standing within such classification schemes. It would be anticipated that matching scheme proposed in Table 3 would deliver desirable outcomes when the composite is subjected to full-scale testing as mandated by law or regulation. 
     
       
         
               
             
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Scheme For Matching Appropriate Fire Barrier to Foam or Filling Material 
               
             
          
           
               
                   
                 Fire Barrier Level 
                   
               
             
          
           
               
                 Foam Class 
                 1 
                 2 
                 3 
                 4 
               
               
                   
               
               
                 A 
                 Yes 
                 No 
                 No 
                 No 
               
               
                 B 
                 Yes 
                 Yes 
                 No 
                 No 
               
               
                 C 
                 Yes 
                 Yes 
                 Yes 
                 No 
               
               
                 D 
                 Yes 
                 Yes 
                 Yes 
                 Yes 
               
               
                   
               
             
          
         
       
     
     As the invention provides for the use of a plurality of non-homogeneous foams or other filling materials in the upper comfort layer core assembly  40 , the selection scheme for matching barrier to filling material selection would require the selection of the fire barrier level matched to the presence of the highest foam or filling class. For example, if a slab of latex foam (Class A) were glued to a slab of flame retardant treated foam (Class D) then the appropriate fire barrier selection for this element would be a Level 1. However, if the slab of latex were replaced by a slab of gel-infused foam (Class B) the fire barrier selection could be reduced to a Level 2 barrier. In any such event, the fire barrier selection for the upper comfort layer core assembly  40  would be separate from the fire barrier selection process for the lower, interiorly disposed support core structure  20 , since that barrier selection would be determined by the particular material selections for that region of the mattress  10 . 
     For purposes of the invention, the distinction or description of foams or filling materials as being “non-homogeneous” is intended to convey the inventors&#39; intent that foams or filling materials of identical material composition but dissimilar physical properties, e.g., density, ILD, or color, would be deemed to be “non-homogeneous.” Similarly, foams or filling materials that are selected with identical physical properties but dissimilar material composition would also be deemed to be “non-homogeneous.” For purposes of clarity, it is contemplated by the invention that “non-homogeneity” may be achieved merely by a difference on only one attribute of the intended foam or filling material, be it a compositional, physical or structural basis. 
     The benefits of a design approach that promotes user adjustment of comfort features to suit their personal preferences in concert with delivering a replacement strategy for worn or used parts that results in reduced waste stream impact and allows tailoring of fire barrier selections to the specific fuel loads and propensities of foams and resilient filling materials to ignite when exposed to open flame ignition sources is not only contemplated as described herein to be applicable to mattresses, but is anticipated to be applicable to upholstered furniture articles, transportation seating and upholstered articles, and contract furnishing articles as well.