Abstract:
A fire-retardant mattress having at least one sleeping side is disclosed that has an inner support compartment with a generally parallelepiped shape with a top side opposite the sleeping side and a fire-containing compartment covering the top side of the inner support compartment and located between the sleeping side and the inner support compartment. The fire-containing compartment includes a first fire-resistant layer consisting essentially of natural fibers, the first fire-resistant layer being in direct contact with the top side of the inner support compartment, a second fire-resistant layer consisting essentially of natural fibers, the second fire-resistant layer located separate from the first self supporting layer of fire-resistant material, and a plurality of combustible cushioning layers positioned between the first and second fire-resistant layers. The first and second fire-resistant layers form a compartment around the plurality of combustible cushioning layers to delay combustion of the fire-retardant mattress from fully catching fire.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 13/198,631, filed Aug. 4, 2011, which is a continuation of U.S. application Ser. No. 10/934,971, filed Sep. 3, 2004 (now abandoned), each of which is incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains to mattresses and, in particular, to a fire-retardant mattress and a method for manufacturing the same. 
     BACKGROUND OF THE INVENTION 
     Since at least the late 1960s, mattress manufacturers have been concerned with fires in mattresses that have been associated with bedroom fires. During this time, some 30,000 bedroom fires were attributed to mattresses as most of the fires were determined to be caused by cigarette ignition of the mattress resulting from people smoking in bed. An additional 22,000 fires were attributed to open flame ignition of the mattress. Given the large number of fires attributed to cigarette smoking, federal standards were introduced in an attempt to limit the spread of fires that originated on a mattress. 
     In the late 1980s, open flame ignition surpassed cigarette ignition as the main cause of mattress fires. Later it was determined, through several studies, that the primary source of bedroom fires was the burning of bedclothes located on top of the mattress. Furthermore, it was found that the majority of these fires were caused by children playing with ignition sources such as lighters, matches and candles which then ignited the top-of-the-bed accessories such as sheets, blankets and pillows. 
     As a result of these surveys, studies were conducted to improve the understanding of mattress fires. These studies led to the development of a test apparatus that could accurately and consistently simulate the burning bedclothes ignition source. 
     The tests involved placing a mattress/foundation on top of a steel twin-sized bed frame which, in turn, rested on a cement fiberboard surface that formed the bottom of a catch pan. A pair of gas burners was designed to mimic the thermal impact of burning bedclothes. One burner was placed so as to impinge on the top of a mattress surface while the second impinges nearby on the mattress side. The flame generated by the side burner was allowed to burn for 50 seconds while the flame from the top burner burned for 70 seconds. The fires generated by these burners were monitored and it was observed that a typical mattress reached flash-over value in approximately three minutes. 
     As a result of these studies, California established a regulation (Technical Bulletin 603) that required that a fire on a mattress could not exceed 25 mega joules of heat in the first 10 minutes of the fire, or a peak rate of heat release of 200 kW over a 30-minute period. A problem associated with reaching this criterion is that it is difficult to place a fire-retardant barrier on the outside of the mattress as the treatment that allows a barrier to be fire retardant makes the mattress surface hard and uncomfortable to the touch. For this reason, the outer layer of a mattress is typically some type of quilt or ticking material that burns fairly easily and is considered sacrificial material. 
     In residential bedroom fires, three different types of people are at risk from the fire. The first of these is the person in the room in which the fire originates and is intimate with the fire. This person would normally be someone on the mattress. The second person is in the room in which the fire originates, but is not intimate with the fire. This could be someone sitting in a chair in the bedroom in which the mattress catches fire or a child who started the fire and is hiding behind a dresser. The third person is someone who is not in the room in which the fire originates and is also not intimate with the fire. This would include someone located in another room in the house in which the mattress catches fire. 
     The regulation promulgated in Technical Bulletin 603 provides a valuable 30-minute window for the people at risk to detect and escape a fire. Furthermore, the low-peak-heat-release limit will substantially delay the growth and intensity of a fire. Combined, these requirements significantly reduce the risk of rapid flashover to other parts of the residence and thus substantially expand the opportunity for consumers to escape a bedroom fire. 
     By reducing the size and growth rate of a fire, it is possible to reduce bed fire casualties by one-half to two-thirds. This is because extra time to escape the residence is provided, particularly for those individuals who are not intimate with the fire. Furthermore, additional time is also provided for a person on the mattress to escape with only isolated burns, if any. 
     In practice, mattress manufacturers follow either or both of two approaches to fire risk reduction: (a) reduce the likelihood of sustained ignition and (b) mitigate the consequences of an ignition. To help achieve these goals, typical fire-resistant mattresses have a fire-resistant barrier located near the outer layer of the mattress, with the outer layer being made of a quilt or ticking material. This fire-resistant barrier works most of the time; however, should the barrier fail, there is no way of preventing the fire from spreading rapidly through the mattress to the inner support compartment, thereby causing a flashover and engulfing the entire mattress in flames. For this reason, the ability to slow the spread of fire that has breached the first fire-resistant barrier would be an important improvement in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, a fire-retardant mattress having at least one sleeping side includes an inner support compartment with a generally parallelepiped shape with a top side opposite the sleeping side, and a fire-containing compartment covering the top side of the inner support compartment and located between the sleeping side and the inner support compartment. The fire-containing compartment includes a first fire-resistant layer consisting essentially of natural fibers, the first fire-resistant layer being in direct contact with the top side of the inner support compartment, a second fire-resistant layer consisting essentially of natural fibers, the second fire-resistant layer located separate from the first self supporting layer of fire-resistant material, and a plurality of combustible cushioning layers positioned between the first and second fire-resistant layers. The first fire-resistant layer and the second fire-resistant layer form a compartment around the plurality of combustible cushioning layers so as to delay combustion of the fire-retardant mattress from fully catching fire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective, cut away view of a portion of a mattress constructed in accordance with the prior art. 
         FIG. 2  is a perspective, cut away view of a portion of one embodiment of a mattress made in accordance with the principles of the present invention. 
         FIG. 3  is a perspective, cut away view showing a top portion of a mattress constructed in accordance with the principles of the invention. 
         FIG. 4  is a sectional view of one embodiment of a single-sided mattress made in accordance with the principles of the invention. 
         FIG. 5  is a sectional view of one embodiment of a double-sided mattress made in accordance with the principles of the invention showing the perimeter of the mattress protected with combustible material compartmentalized between two layers of fire-resistant material. 
         FIG. 6  is a sectional view of a single-sided embodiment of a mattress made in accordance with the principles of the invention showing the inner support compartment filled with foam. 
         FIG. 7  is a sectional view of a double-sided embodiment of a mattress made in accordance with the principles of the invention showing the inner support compartment filled with foam and the perimeter two layers of fire-resistant material compartmentalizing the combustible material. 
         FIG. 8  is a perspective, cut away view showing a top portion of a mattress constructed in accordance with the invention, the mattress having a plurality of combustible layers of material between the two layers of fire-resistant material. 
         FIG. 9  is a sectional view of a pillow-top mattress. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 2-7  show the invention which is directed to a fire-resistant mattress  10  that uses layers of fire-resistant material  14 ,  18  to compartmentalize material  16  within the mattress  10  so as to delay and possibly prevent the mattress  10  from becoming fully engulfed in flames as the result of the mattress  10  catching on fire. 
     As shown in  FIG. 1 , conventional fire-resistant or fire-retardant mattresses  100  include a single fire-resistant layer of material  17 . This fire-resistant layer  17  is located near, if not directly beneath, the outer layer  19  of the mattress  100 . In the event of a mattress fire caused, for example, by the bedding (not shown) on top of the mattress  100  catching on fire, the flame burns through the combustible outer layer of quilt or ticking  19 . Although the fire-resistant layer  17  works most of the time, should the flame breach (i.e., burn through) the layer  17 , there is no additional protection or barrier to prevent the fire from rapidly spreading through the rest of the mattress  100 , thereby resulting in a high rate of combustion of the mattress  100 . In still another embodiment of the prior art the outer layer  19  may itself be fire resistant. This eliminates the need for a second fire resistant layer such as  17  in  FIG. 1 . 
     For purposes of this invention, flashover is that point in time where the articles burning in a room generate enough energy to cause all room ingredients to burn essentially simultaneously. This point is normally accepted to be about 1,000 kW in a regular sized bedroom. Furthermore, for the purposes of this invention, the terms fire resistant and fire retardant are used interchangeably. 
       FIG. 2  shows one embodiment of the invention in which the fire-resistant mattress  10  is comprised of an inner support compartment  12 , a first layer of fire-resistant material  14  adjacent to at least one side  13  of the inner support compartment  12 , at least one layer of material  16  adjacent to the first layer of fire-resistant material  14 , and a second layer of fire-resistant material  18  adjacent to the at least one layer  16 , the second layer of fire-resistant material  18  being distal to the first layer of fire-resistant material  14 . This use of fire-resistant layers of material  14 ,  18  on each side of the layer  16  creates a compartment  20  that helps to contain the fire from spreading throughout the mattress  10  should one of the fire-resistant layers  14 ,  18  be breached. 
     The at least one layer of material  16  that is compartmentalized between the fire-resistant layers  14 ,  18  can be a combustible material as well as a cushioning material. Furthermore, the layer of material  16  may be combustible material that has been treated with a fire-resistant chemical. 
     The compartmentalization of the material  16  results in fire-resistant integrity for the mattress  10  in much the same way that watertight doors provide watertight integrity in the event of flooding in a ship. That is, by containing the flooding within a specific compartment, the complete flooding of the ship is prevented, thereby increasing the chances of saving the entire ship. In the inventive mattress  10 , fire is contained within the compartment  20  between the fire-resistant layers  14 ,  18  even in the event of the fire breaching one of the layers. 
     As shown in  FIG. 2 , the use of a first fire-resistant layer of material  14  located further inboard of the outer layer  22  of the inventive mattress  10  and closer to the inner support compartment  12  than the second fire-resistant layer  18 , provides an additional layer of fire protection, thereby slowing the advance of the fire and allowing additional time for an individual to escape the room or building in which the mattress is located. 
       FIGS. 2 ,  3 ,  4 ,  6  and  8  show one embodiment of the inventive mattress  10  in which at least one layer of material  16  is located between a first and second layer of fire-resistant material  14 ,  18  that are positioned on one side  13  of the inner support compartment  12 . This type of mattress  10  is known as a single-sided mattress, as the top side of the inner support compartment  12  is built up with thicker upholstery material than the bottom or second side. In such a single-sided mattress, the side of inner support compartment  12  opposite of the sleeping side may be covered with one or more upholstery layers; however, it is not designed to be a sleeping surface. Of course, additional layers of materials  23 , such as foam, quilt, and upholstery topper layers may be included between the layers of fire-resistant material  14 ,  18 , as shown in  FIG. 4 , without departing from the scope and spirit of the invention. 
     When in use, should a fire start on the top of the mattress  10  shown in  FIGS. 2-9 , the flame will readily penetrate the outer layer of quilt or ticking  22 , as well as any other sacrificial combustible material (e.g.,  25  in  FIGS. 4 and 6 ). Once the flame reaches the second layer of fire-resistant material  18 , however, its rate of penetration will be slowed, if not completely stopped. 
     The layers of fire-resistant material  14 ,  18  used in the mattress  10  can be manufactured as a barrier sheet or a high loft batt. The layers  14 ,  18  may be made of blends of synthetic or natural fibers. Examples of natural fibers may include cotton fibers and the like. Such fire-resistant layers  14 ,  18  are manufactured by several companies including, but not limited to, Basofil Fibers, LLC, Leggett &amp; Platt, and Jones Fiber. 
     Should the second layer of fire-resistant material  18  be breached as a result of a tear in the fire-resistant layer, a flaw in the material, or any other reason, the fire will then spread through the layer(s) of material  16  immediately beneath the second fire-resistant layer  18 . The fire will continue to advance in a controlled manner until it reaches the first layer of fire-resistant material  14  where it will once again be slowed, thereby delaying the involvement of the entire mattress  10 . 
     This additional barrier of protection resulting from the first (i.e., inner) layer of fire-resistant material  14  helps contain the fire within the compartment  20  bordered by the two layers of fire-resistant material  14 ,  18 . This compartmentalization of the fire slows or prevents the mattress  10  from being completely engulfed by fire, thereby increasing the length of time an occupant in the room or building housing the mattress has to flee to safety. 
     Although not 100% foolproof, the extra protection offered by the first (i.e., inner) layer of fire-resistant material  14  helps reduce the amount of heat generated by the fire, thereby allowing the mattress to burn for 30 minutes without exceeding 200 kW. 
     The inner support compartment  12  of the inventive mattress may be filled with any suitable material known in the art, including springs, air, water, foam or fiber.  FIGS. 2-5 ,  8  and  9  show an inner support compartment  12  filled with springs  24 , while  FIGS. 6 and 7  show the compartment  12  filled with foam, fiber or other material  26 . A layer of material  23  may also be located adjacent to the second layer of fire-resistant material  18  either distal or proximal to the at least one layer of cushioning material  16 , as is shown in  FIGS. 4-7 . The cushioning material  16  may also be made of any suitable material, including foam and/or fiber. 
     In another embodiment of the invention, as shown in  FIG. 3 , at least one upholstery layer  30  is adjacent to the at least one side  13  of the inner support compartment  12  and the first layer of fire-resistant material  14  is adjacent to the at least one upholstery layer  30 , but distal to the at least one side  13  of the inner support compartment  12 . This allows for one or more layers of material  30  to be located between the inner support compartment  12  and the first layer of fire-resistant material  14 . The inner support compartment  12  may also have a perimeter  11  that is surrounded by a layer of fire-retardant material  38 , as shown in  FIGS. 5 and 7 . 
     In still another embodiment of the invention, as shown in  FIGS. 5 and 7 , the inner support compartment  12  has a second side  15  opposite the at least one side  13 . A third layer of fire-resistant material  32  is located adjacent to the second side  15  of the inner support compartment  12 , at least one layer of material  34  is adjacent to the third layer of fire-resistant material  32 , and a fourth layer of fire-resistant material  36  is adjacent to the at least one layer of material  34  distal from the third layer of fire-resistant material  32 . This type of mattress  10  is known as a double-sided mattress as cushioning material is located on both sides of the inner support compartment  12 . 
     The compartmentalization of the at least one layer of material  34  on the second side  15  of the inner support compartment  12  works in the same way as does the compartmentalization on the first side  13 . That is, the third and fourth layers of fire-resistant material  32 ,  36  act to contain any fire in the area between them, much in the same manner that two watertight doors contain flooding within a particular compartment on a ship. As with the single-sided mattress, the at least one layer of material  34  located between the third and fourth layers of fire-resistant material  32 ,  36  may be made of a combustible material and/or a cushioning material including, but not limited to, foam. The layer  34  may also be made of a combustible material that has been treated with a fire-resistant chemical. 
       FIG. 8  shows still another embodiment of the invention wherein the mattress  10  has an inner support compartment  12 , a fire-resistant insulation layer  14  having a first side and a second side positioned so that the first side is adjacent to at least one side of the inner support compartment  12 , a first layer of material  16  is adjacent to the second side of the first fire-resistant layer  14 , a quilt backing layer  42 , having a first side and a second side, is positioned so that the first side of the quilt backing layer  42  is adjacent to the first layer of material  16 , yet distal from the first fire-resistant layer  14 , a second layer of material  44  is adjacent to the second side of the quilt backing layer  42 , a second fire-resistant insulation layer  18  is located adjacent to the second layer of material  44  and distal from the quilt layer  42 , and an outer layer  46 , such as a ticking layer, is adjacent to the second fire-resistant layer  18 . Again, this arrangement of building up the mattress using a first and second layer of fire-resistant material  14 ,  18  to establish a compartment  20  in which bedding material  16 ,  42 ,  44  is located helps reduce the fire growth of the mattress. 
       FIG. 9  shows still another embodiment of the invention wherein the mattress  10  includes at least one additional layer of material  48  secured to a top layer  50  of the mattress  10 . In this embodiment, known as a pillow-top or Euro-top mattress, the at least one additional layer of combustible material  48  is joined to the top layer  50  inboard of the perimeter of the mattress  10 . This creates a void or “smile”  52  between the top layer  50  of the mattress  10  and the at least one additional layer  48 . An additional layer of fire-resistant material  28  extends along the length of the mattress  10  adjacent to the at least one additional layer  48 . At least one layer of material  16  is located next to the additional layer of fire-resistant material  28 , proximal to the inner support compartment  12 . A first layer of fire-resistant material  14  is located inboard of the at least one layer of combustible material  16  between the combustible material  16  and the inner support compartment  12 , while a second layer of fire-resistant material  18  is located between the two layers of combustible material  16 . 
     The invention also includes a method for manufacturing a fire-resistant mattress. This method of manufacturing involves the steps of: (a) providing an inner support compartment; (b) placing a first layer of fire-resistant material on a first side of the inner support compartment; (c) positioning at least one layer of combustible material adjacent to the first fire-resistant layer of material; (d) aligning a second layer of fire-resistant material on the at least one layer of combustible material distal to the first layer of fire-resistant material; and (e) placing a second layer of sacrificial combustible material outboard of the second layer of fire-resistant material distal to the inner support compartment. These materials may be independent or contained in a quilt. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential of the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.