Abstract:
The subject invention comprises a flexible multilayer fire-rated material that has at least one layer of an intumescent material. Because it is flexible, the fire-rated material is usable in situations where it is desirable for the fire-rated material to be rolled up or folded into a non-flat storage application. This allows the subject fire-rated material to be used in fire-rated and smoke-resistant barriers that are recessed in walls or ceilings until use. One end use embodiment includes without limitation, recessed or rolled up fabrics used in elevator lobby ceilings to seal off elevators or their lobbies from smoke or fire.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/253,059, filed Oct. 19, 2009 and titled FIRE PROOF MULTILAYER FABRIC WITH INTUMESCENT LAYER, which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure is directed to flexible heat and vapor barriers capable of withstanding exposure to extreme heat and pressure from an impinging stream of water such as from a fire hose. 
       BACKGROUND 
       [0003]    In order to protect people in high rise buildings from smoke migrating in elevator shafts (as occurred in the infamous MGM fire in Las Vegas in 1980) high rise buildings are built with barriers in elevator lobbies which prevent smoke from moving from floor to floor. In many instances these barriers are simply doors and walls that are used to segregate an elevator lobby or an individual elevator. However, the downside of these doors and walls is that they can be unsightly and cause restrictions on architects who often prefer a more open look and feel to their buildings. 
         [0004]    Accordingly, some architects choose to use barriers that are recessed in ceilings or walls and only become visible if there is a fire. These recessed barriers are by necessity flexible fabrics or other materials which can be rolled up into a recessed cavity when not in use. They can be rolled down to form a barrier when there is a fire or smoke event. These flexible recessed barriers are well known in the art and different configurations can be bought from companies, such as SmokeGuard Inc. of Boise, Id. 
         [0005]    These flexible barriers are typically effective at preventing smoke migration, but some are not designed to prevent migration of an intense fire. Some flexible barriers have been found that can withstand the high temperatures of a fire, but some certification tests require that they also are able to withstand the violent blasts from a high pressure water hose that might be used by firemen. Examples of performance requirements are set forth by standardized tests such as the UNDERWRITER LABORATORIES™ 10C test (“UL 10C”) and the American Society for Testing and Materials (ASTM) E119 test (“ASTM E119), which are both incorporated herein in their entirety. There are several tests in use in different industries and different areas. These tests generally describe a time-temperature curve. Some data points on the curve that determine the character of the curve are as follows:
       1000° F. (538° C.) at 5 minutes   1300° F. (704° C.) at 10 minutes   1462° F. (795° C.) at 20 minutes   1550° F. (843° C.) at 30 minutes   1638° F. (892° C.) at 45 minutes   1700° F. (927° C.) at 1 hour   1792° F. (978° C.) at 1½ hours   1850° F. (1010° C.) at 2 hours   1925° F. (1052° C.) at 3 hours   2000° F. (1093° C.) at 4 hours
 
The barriers according to the present disclosure are capable of passing these tests.
       
 
         [0016]    Finally, it would be especially beneficial if these flexible barriers could also provide some type of improved insulation from the heat of a fire on one side so that persons on the other side of the barrier have a better chance of survival and the creation of a tenable environment can be established should egress from a building be necessitated by an egress elevator. 
         [0017]    Accordingly, what is needed is a flexible smoke barrier that can be rolled up into a recessed space but which can also withstand intense heat, a high pressure water hose blast, thermal quenching and also have insulation properties to help minimize the heat transfer from the fire side of the barrier to the other side of the barrier. 
       SUMMARY 
       [0018]    Aspects of the new fire barrier in accordance with embodiments of the present disclosure include a layered system of textile materials, intumescent materials, and special purpose materials capable of passing standardized tests such as the UL 10C test. In some embodiments, the materials can be treated with selected chemicals, such as hydrates, to further reduce the thermal conductivity of the materials. In some embodiments, the barriers are formed of at least two segments of material, which can be seamed together using reinforced stitching to strengthen the barrier against an impinging stream of water even after the barrier has been exposed to intense heat. 
         [0019]    Some embodiments of the present disclosure include a flexible barrier, comprising a sheet of material having a leading edge, a trailing edge attached to a spool, and two lateral edges. The sheet of material has containment loops at the lateral edges. The containment loops are configured to engage a rail in a passageway of a structure, and the sheet of material is configured to wind onto and off of the spool between an open position in which the sheet of material is wound on the spool and a closed position in which the sheet of material is at least partially unwound from the spool and blocks the passageway. The sheet of material can be made of a plurality of layers, such as an insulative layer having a first side and a second side, a first sacrificial layer on the first side of the insulative layer, and a second sacrificial layer on the second side of the insulative layer. The sacrificial layers can be consumed if the barrier is exposed to heat above a predetermined threshold. 
         [0020]    In some embodiments, the barriers include a multi-layer, bi-directional barrier. The barriers can include a strength layer having a first side and a second side, a first phase decomposition layer on the first side of the strength layer and a second phase decomposition layer on the second side of the strength layer. The first and second phase decomposition layers can include an intumescent layer that will char when heated above a predetermined threshold temperature. The barriers can further include a first thermally reflective layer on the first phase decomposition layer and a second thermally reflective layer on the second phase decomposition layer. The first and second thermally reflective layers and the first and second phase decomposition layers can be exfoliant layers that release from the barrier when impinged by a stream of water of a predetermined volume level after the barrier is exposed to heat above a predetermined threshold. 
         [0021]    In some embodiments, the barriers can be made according to a method including forming a base layer from a flexible, thermally insulative intumescent sheet of material having a first sacrificial layer on a first side of the base layer and a second sacrificial layer on a second side of the base layer. The first and second sacrificial layers can be thermally reflective. The method can also include attaching the barrier to a retracting mechanism into which the barrier can be retracted when not in use. 
         [0022]    In still further embodiments, the barriers are flexible enough to be rolled and unrolled to fit within recessed smoke and fire barriers as a substitute for fire walls and fire doors. In selected embodiments, the barriers have many layers, including a base fire resistant layer made of a material such as a silica cloth. The base material can then be covered, impregnated, or sprayed with an intumescent material. Intumescent materials are materials which have fire protective properties because they expand dramatically when exposed to high heats to form a carbon based nonflammable char material. The char material also helps protect the non-exposed base material from the physical damage caused by the high pressure fire hose, in particular at seams in the base material. In some embodiments, the intumescent material is then covered by a third layer opposite the base layer. This third layer can also be made of a heat resistant or heat reflective material. Barriers according to the new technology can help protect persons and property from exposure to the heat of the fire. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is a partially schematic view of a flexible heat and vapor barrier deployed in a passageway in a structure according to embodiments of the present disclosure. 
           [0024]      FIG. 2  is a schematic isometric view of a flexible heat and vapor barrier material comprising an insulative layer and two thermally reflective layers according to embodiments of the present disclosure. 
           [0025]      FIG. 3  is a schematic isometric view of a flexible heat and vapor barrier material comprising a strength layer, two insulative layers, and two sacrificial thermally reflective layers according to other embodiments of the present disclosure. 
           [0026]      FIG. 4  is a schematic isometric view of a flexible heat and vapor barrier having several seams and containment loops according to embodiments of the present disclosure. 
           [0027]      FIG. 5A  is an enlarged cross-sectional view of a stitch for a containment loop of a flexible heat and vapor barrier according to embodiments of the present disclosure. 
           [0028]      FIG. 5B  is an enlarged cross-sectional view of a vertical seam for a flexible heat and vapor barrier according to embodiments of the present disclosure. 
           [0029]      FIG. 5C  is an enlarged cross-sectional view of a horizontal reinforcement strip for a flexible heat and vapor barrier according to embodiments of the present disclosure. 
           [0030]      FIG. 6  is a partially schematic view of a stitch pattern for a flexible heat and vapor barrier according to embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]      FIG. 1  illustrates a barrier system  100 , including a barrier  110 , a spool  120 , and a set of rails  130 . The barrier  110  can wind onto and off of the spool  120  as it moves between a deployed position and a retracted position. The barrier  110  can include containment loops that receive at least a portion of the rails  130 , and as the barrier  110  unwinds from the spool  120 , the containment loops move along the rails  130 . The rails  130  can be affixed to walls  140  of a structure, such as a building or a ship. The barrier system  100  is shown in  FIG. 1  having the barrier  110  suspended between the walls  140 . More details of the barrier system  100  are given in patent application Ser. No. 11/828,974 filed on Jul. 26, 2007 and published on Feb. 4, 2010 as U.S. Patent Application Publication No. 2010/002499A1, which is incorporated herein by reference. The barrier system  100  is an example of a deployable barrier which can be retracted for storage when not in use. The systems and methods described herein can be applied equally for embodiments of static barriers that are not retractable. 
         [0032]      FIG. 2  illustrates an embodiment of the present disclosure including a barrier  200  made of an insulative layer  210 , a first strength layer  220   a  and a second strength layer  220   b.  The insulative layer  210  is positioned between the first strength layer  220   a  and the second strength layer  220   b.  The insulative layer  210  can include intumescent materials, or it can include a base substrate that is coated, impregnated, or sprayed with intumescent materials. For example, the insulative layer  210  can be a nonwoven, fabric-like material made from long fibers, bonded together by chemical, mechanical, heat or solvent treatment. Nonwoven materials include fabrics, such as felt or rock wool, which are neither woven nor knitted, and are generally highly insulative to high temperatures. The intumescent materials can include hydrates which release moisture when heated which further reduces the thermal insulative properties of the insulative layer  210 . The strength layers  220   a  and  220   b  can each be a standard refractory screen fabric, such as a silica coated silicon dioxide fabric. In some embodiments, the strength layers  220   a  and  220   b  are thermally reflective. The strength layers  220   a  and  220   b  can be coated, dipped, impregnated, or painted with a reflective material such as foil to reflect radiative heat. 
         [0033]    The strength layers  220   a  and  220   b  can also be sacrificial layers. As the name implies, the sacrificial layers  220   a  and  220   b  may lose mechanical strength when exposed to intense heat such as produced by a fire in a structure. Suppose the first strength layer  220   a  is exposed to heat and the second strength layer  220   b  is not. The first layer  220   a  will initially reflect heat, but will likely yield to the heat after enough exposure. After the first layer  220   a  is mechanically compromised, the insulative layer  210  continues to insulate the barrier  200  for an extended period of time. While the insulative layer  210  remains, and even after the insulative layer  210  is charred by fire (and perhaps removed due to an impinging jet of water), the second strength layer  220   b  will withstand the heat for yet another period of time before ultimately yielding to the heat. In some embodiments, the second strength layer  220   b  has sufficient strength to withstand an impinging stream of water from a fire hose even after the first strength layer  220   a  and the insulative layer  210  are compromised by heat. The barrier  200  can therefore pass many standardized tests for fire-rated barriers, such as the UL 10C test, the ASTM E119 test, the NFPA 252 test, the UL 263 test, etc. At least one component of these tests is withstanding exposure to a predetermined heat threshold (e.g., 1700° F.) for a given period of time, and after the heat exposure, the barrier must withstand a stream of water such as a fire hose for a certain period of time (e.g., 2 minutes). The barrier  200  is sufficiently strong to pass the tests, but is much less bulky and cumbersome to operate than a steel door or other rigid barrier. 
         [0034]      FIG. 3  illustrates a further embodiment of a barrier  300  according to the present disclosure. The barrier  300  can include a strength layer  310 , and a first insulative layer  320   a  and a second insulative layer  320   b  on either side of the strength layer  310 . The strength layer  310  can be made of NOMEX™, Silica Cloth, Fiber Glass, or another suitable material. In one embodiment, the strength layer  310  is made of a silica cloth (silicon dioxide 96% mass and metal oxidation 4% mass). The barrier  300  can also include a first thermally reflective layer  330   a  on the first insulative layer  320   a , and a second thermally reflective layer  330   b  on the second insulative layer  320   b.  In some embodiments, the barrier  300  can be symmetrical about the strength layer  310 , with the first insulative layer  320   a  and first thermally reflective layer  330   a  being substantially identical to the second insulative layer  320   b  and second thermally reflective layer  330   b,  respectively. The strength layer  310  can be a flexible, fabric layer made of silicon dioxide cloth. In some embodiments, the strength layer  310  is not necessarily resistant to heat, but has relatively high mechanical strength. The insulative layers  320   a  and  320   b  can be generally similar to the insulative layers  220   a  and  220   b  shown and described above with respect to  FIG. 2 , and can include intumescent materials and other thermally insulative materials. The thermally reflective layers  330   a  and  330   b  can be a foil coating, or a thin layer impregnated with thermally reflective particles. Other thermally reflective materials can also be used. In each of the embodiments described herein, the various layers of the barriers  200  or  300  can be held together by any of a number of different attachment methods or techniques, including adhesives, pressure melding, solvents that fuse the layers, crimping, stitching and so forth. 
         [0035]    The barrier  300  can be symmetric, and can generally withstand exposure to heat from either side of the barrier  300 . For example, if the barrier  300  is installed near an entrance to an elevator lobby with the first insulative layer  320   a  facing the elevators, a fire in the elevator lobby will affect the first thermally reflective layer  330   a  and the first insulative layer  320   a  before affecting other layers of the barrier  300 . In many applications, it can be difficult to predict where a fire will occur, so the barrier  300  is capable of withstanding exposure to heat from either side. When exposed to heat such as from a fire, the thermal layer  330   a  facing the heat source will reflect as much heat away from the barrier  300  as possible but will, in time, be consumed. The first insulative layer  320   a  then can insulate the strength layer  310  from the heat. In some embodiments, the barrier  300  is strong enough to withstand exposure to heat of approximately 1700° F. After being exposed to the heat, the barrier  300  can be sprayed with a fire hose for approximately 2 minutes, as required by the various standards. The strength layer  310  is strong enough to withstand this pressure. There are many standardized building code tests referenced above which provide details regarding the heat exposure, and the volume, pressure, time, and direction of the water stream. The barrier  300  according to the present disclosure can pass these tests, and in addition, is flexible enough to be rolled away and stowed while not in use. 
         [0036]      FIG. 4  depicts a barrier  400  according to an embodiment of the present disclosure in which the barrier  400  is made of several sheet segments with seams between the segments. The barrier  400  can be made of the materials described above with reference to  FIGS. 2 and 3 . In one embodiment, the barrier  400  includes first segments  410   a  and  410   b  joined by a vertical seam  412 . The barrier  400  can also have horizontal reinforcement strips  414   a  and  414   b  between first segments  410   a  and  410   b  second segments  410   c  and  410   d.  The barrier  400  can have containment loops  416  at lateral sides of the barrier  400  that engage rails  418  to guide the barrier  400  into and out of position in a structure, generally as described above with reference to  FIG. 1 . 
         [0037]      FIG. 5A  illustrates a cross-sectional view of a containment loop  416  and a seam  420  shown along section A-A in  FIG. 4  according to the present disclosure. The containment loop  416  can include a folded section of the barrier  400  that surrounds the rail  418 , and is stitched to the barrier  400  by a stitch  421 . The stitch  421  can be a reinforced French stitch in which the end of the barrier  400  is folded under, and the stitch  421  (or stitches) passes through three or more layers of the barrier material. In some embodiments, an insulating layer extends to the seam  420  but does not surround the containment loop  416 . 
         [0038]    The segment  410   a  of the containment loop  416  can comprise a first strength layer, a second strength layer, and an insulative layer between the first and second strength layers, similar to the embodiment described above with respect to  FIG. 2 . In this embodiment, the first and second strength layers are both sacrificial. After a period of exposure to heat, the strength layer facing the heat will be compromised mechanically, while the “leeward” strength layer that does not directly face the heat will maintain its mechanical strength. In this embodiment, the containment loop  416  includes a layer from each strength layer, so regardless of which side is exposed to the heat the containment loop  416  will not fail as long as the leeward strength layer maintains its strength. In some embodiments, the containment loops  416  can be recessed within a wall of a passageway to prevent direct exposure of the containment loops  416 . 
         [0039]      FIG. 5B  illustrates a cross-sectional view of a vertical seam  422  along section B-B in  FIG. 4  according to the present disclosure. The seam  422  can be made by folding a portion of segments  410   a  and  410   b  over one another, and then placing one or more stitches  421  through four layers of the barrier material as shown. This seam  422  shields the stitching from the most intense heat, and helps provide the mechanical strength necessary even after exposure to the heat to withstand the stream of water dictated by the standardized tests such as the UL 10C test.  FIG. 5C  illustrates a horizontal reinforcement strip  424  that can be used to reinforce the a seam between two segments  410   a  and  410   b  along section C-C of  FIG. 4 . The barrier  400  can be joined by a simply overlapping the two segments  410   a  and  410   c  (or  410   b  and  410   d ) and placing a stitch  421  between the segments  410   a  and  410   c.  A strip of reinforcing material  426  can be placed between the segments  410   a  and  410   b  with ends folded under, in a C-shape. Stitches  421  can be placed through the reinforcing strip  426  and through the barrier  400 . It is to be understood that the seams  420 ,  422 , and the reinforcing strip  424  shown in  FIGS. 5A ,  5 B, and  5 C can be used in different portions of a single barrier  400 , or different barriers can include the seams described in  FIG. 5A ,  5 B, or  5 C independently. 
         [0040]      FIG. 6  illustrates another seam configuration  430  for use with a barrier  400  in accordance with the present disclosure.  FIG. 6  shows an enlarged view of a section labeled D in  FIG. 4 . This seam configuration  430  can be used between a containment loop  416  and a horizontal seam  424 , similar to those described above. At a lateral edge  432  of the barrier  400 , several lines  434  of stitching can be placed in the barrier  400  to seal the containment loop  416 . These lines  434  can intersect with a horizontal seam  424  similar to the seam shown in  FIG. 5C , or another type of seam. Different arrangements and stitching patterns can be used, including a reinforcing strip over the stitching lines  434 . 
         [0041]    From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Additionally, aspects of the invention described in the context of particular embodiments or examples may be combined or eliminated in other embodiments. Although advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages. Additionally not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.