Abstract:
An intumescent laminate vapor barrier is fabricated with a fire-resistant putty. This has the advantage that it slows down the transmission of heat, expands when being exposed to temperature and thereby seals the cracks which could have been formed during the installation. It also protects the structures (framings) from fire and the sheathing made up of gypsum-boards, plywood, Oriented Strand Boards (OSB) or any other type.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    It is a known fact that when people use baths, kitchens and sinks inside a house, this generates a significant amount of water vapor. This vapor is retained by the air inside a house, which in turn increases its degree of humidity in relation to the air outside of the house. 
         [0002]    Since most construction material is permeable to the passage of water vapor, this humidity penetrates the walls and ceilings to approach the external walls of the buildings, which are generally colder than the interior walls where the steam originates from. This causes the vapor to condensate, which in turn makes contact with the sheathing materials, both structural and insulating, all of which causes serious damage when prolonged in time. Both fiberglass and rock-wool lose their effectiveness when they absorb humidity, loosing their insulating effectiveness. It is for these reasons that contact between the water vapor and the constructive materials at the inside of the house should be avoided, particularly when the construction framings are made of wood. To achieve this, humidity barriers are used. The barrier most commonly used is polyethylene, given its low levels of so-called permeability, or passage of vapor through its structure. For this to be effective, the barrier must be placed on the warmest surface of the structure. In normal conditions, the polyethylene works and protects suitably. However, in case of fire, it even loses its watertightness which can even result in it to start to burn, which only contributes in aggravating the problem. It is known, for example, that when gypsum-boards are used, as is usually the case with wood constructions, these collapse when the temperature surpasses a certain value. It is known that plaster, which is a di-hydrated calcium sulphate, begins to lose the water of hydration at 128° C., and loses it completely at 168° C. When losing the water, a retraction takes place in the plaster which makes is crack and pulverize, thereby losing its mechanical properties which results in the structure collapsing. Once the gypsum board has collapsed, the wood frames are exposed to the fire, and these start to carbonize. 
       SUMMARY OF THE INVENTION 
       [0003]    An intumescent laminate vapor barrier is fabricated with a fire-resistant putty. This has the advantage that it slows down the transmission of heat, expands when being exposed to temperature and thereby seals the cracks which could have been formed during the installation. It also protects the structures (framings) from fire and the sheathing made up of gypsum-boards, plywood, Oriented Strand Boards (OSB) or any other type. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  shows an isometric view, in a partial cut, of a structural wall assembly. 
           [0005]      FIG. 2  shows a cross section of a wall assembly, made up of an Oriented Strand Board (OSB) on the outside, and a standard gypsum board on the inside, separated by a wood structure of radiata pine. 
           [0006]      FIG. 3  shows a frontal-elevation view of the assembly of  FIG. 2 , showing the position of four thermal-sensors. 
           [0007]      FIG. 4  shows a profile-view of the assembly of  FIG. 2 , placed in the furnace for fire-resistance testing. 
           [0008]      FIG. 5  shows an isometric view of a structural assembly for testing. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0009]    The present invention comprises producing a membrane or laminate of between 0.2 and 5 mm thickness, and preferably of between 0.5 and 2 millimeters of thickness, by means of a methodology of pressing, laminated in rollers, stretched, or by whatever other means by which to stretch an intumescent inorganic putty, which is self-adhesive and fire-resistant as indicated in the United States Patent Application Publication Number 20070234930 (hereby incorporated by reference in its entirety) or another one, which allows to obtain a laminate, preferably of uniform thickness in all its extension, to be applied as a vapor or humidity barrier in wall assemblies or ceilings with framings made of wood, steel or other materials, whatever the characteristics of their surface. 
         [0010]    The thickness of the laminate to be used depends on the fire-resistance required, whereas the dimensions of width and length depend on the project in which it is to be applied. 
         [0011]    In one of its forms, and without this limiting the invention to it, this consists of producing a membrane of one millimeter thickness, which is obtained with an amount of about 1400 grams (dry weight) of putty by square meter of laminate, which then reaches a rigid consistency when it is covered by both sides with paper; semi-rigid when it is covered by only one side with paper and flexible for 48 hours, while it remains without being covered, after which it becomes rigid. The superficial coating also can be of other laminated materials, like for example thin fabrics of natural or synthetic fibers, or others. 
         [0012]    Another form of producing this invention consists of producing the laminate by impregnating the putty into a fiberglass fabric, or a cloth made with natural synthetic fibers or others, woven or pressed, covered or not with paper on its external faces. Like in the accomplishment of the previous paragraph, the thickness and dimensions depend on the requirements of each application. Just as indicated in the previous paragraph, the impregnated fabrics or cloths can be covered on their surfaces by laminates of paper or other thin laminar materials of any type. 
         [0013]    Another form of realizing this invention consists in applying the laminate directly on the surfaces which are to be protected, thereby applying the putty by means of manual or industrial methods. 
         [0014]    The adhesion of the laminate to a wood board of any type can also be performed by applying pressure, either by pressed or roller system, in both cold or hot forms, as long as the temperature is less than one hundred degrees Celsius. The temperature can be slightly superior to one hundred degrees Celsius when the substrate to be protected is a fabric or cloth of fiberglass, or when the board is of plaster or fibre-cement. 
         [0015]    These laminates, when used like a vapor barrier, allow to solve the problem which current humidity barriers have, namely that in case of fire the current humidity barriers not only do not slow down the propagation the fire, but by being easily combustible products actually aggravate the problem as they tend to burn at very low temperatures. 
         [0016]    Another advantage of this invention is the feasibility of depositing or applying the laminate with coating on one side or even without any coating, or laminating it directly on any type of board, like Oriented Strand Board (OSB), plywood board, gypsum board, steel boards, etc., by it being self-adhesive from the moment it is manufactured and for a period of up to two hours after this. If the gypsum board is covered on one side by the fire-retardant putty, and this side faces the interior of the house, then the fire-retardancy effect is further enhanced, since as the transmission of heat is delayed, the temperature of dehydration of the plaster takes much longer to reach, delaying the moment at which the wood frames on the inside of the wall assemblies are directly exposed to the fire. 
         [0017]    The use of two laminates, one to each side of the insulating material inside the wall assembly, increases the fire resistance considerably. 
       EXAMPLES OF APPLICATIONS 
       [0018]    This self-adhesive and semi-liquid membrane can be installed to protect a wide array of wood products currently used in construction against fire, such as segments, pillars, T-joists, dividing panels, wall assemblies and fire walls. Is also serves to protect metallic surfaces or structures, doors and elevators. It also increases the fire resistance in gypsum boards, Oriented Strand Boards (OSB), Plywood boards, fibre-cement, fibre-silicate PB, ceilings made of MDF boards, packaging, vehicles, aircraft, etc. 
       Example 1 
     Without Insulation 
       [0019]    In order to evaluate the usefulness of the self-adhesive intumescent membrane, a fire test was performed of a scaled-down structural wall assembly, namely a 50 by 50 centimeters structure formed by an inner board ( 11 ) (exposed to the fire) of a 10 mm width gypsum board, placed on a radiata pine frame ( 13 ,  17 ) of 45 millimeters thickness by 90 millimeters width, covered on the outside by an OSB board ( 18 ) of 9.5 millimeters thickness, without any other insulations in between. 
         [0020]    In order to determine the effectiveness of the semi-liquid membrane, an additional piece of wood was installed ( 15 ) of 45 by 90 millimeters of radiata pine in vertical form in the center of the frame, whereby the laminate of flexible membrane of one millimeter thickness ( 12 ) was placed directly behind the gypsum board on one half ( 11 ). The other half of the structure was left without the protecting membrane. ( FIG. 2  schematically shows the testing frame). 
         [0021]    The furnace used for these small-scale tests has an outer dimension of 65 by 65 by 65 centimeters and an interior dimension of 50 by 50 by 50 centimeters. Its thermal insulation is made up of insulating bricks and its heating is achieved by a system of electrical heaters. The temperature sensors of the furnace and the tested assembly are connected to a computerized system of data input, where all the information of the test is registered in real time. 
         [0022]    For the test, the assembly was placed with the gypsum board facing the furnace, as seen in  FIG. 4 . The furnace warmed up according to the standardized curve of temperature-time of ASTM E 119 standard. The test results are indicated in Table 1: 
         [0000]    
       
         
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
                   
                 Temperature 
                 Temperature 
                 Temperature 
                 Temperature 
                 Temperature 
               
               
                   
                 Temperature 
                 N o  26 of 
                 N o  21 of 
                 N o  22 of 
                 N o  23 of 
                 N o  24 of 
               
               
                 Time 
                 ASTM E 119 
                 Furnace 
                 protected 
                 protected 
                 unprotected 
                 unprotected 
               
               
                 (min.) 
                 (° C.) 
                 (° C.) 
                 area (° C.) 
                 area (° C.) 
                 area (° C,) 
                 area (° C.) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 0 
                 20 
                 20 
                 17 
                 17 
                 18 
                 18 
               
               
                 5 
                 538 
                 595 
                 18 
                 18 
                 21 
                 19 
               
               
                 10 
                 704 
                 686 
                 22 
                 21 
                 31 
                 26 
               
               
                 15 
                 759 
                 741 
                 28 
                 25 
                 41 
                 37 
               
               
                 20 
                 794 
                 786 
                 33 
                 30 
                 54 
                 49 
               
               
                 25 
                 821 
                 817 
                 38 
                 35 
                 72 
                 62 
               
               
                 30 
                 843 
                 843 
                 45 
                 41 
                 87 
                 76 
               
               
                 35 
                 862 
                 864 
                 52 
                 48 
                 100 
                 85 
               
               
                 40 
                 878 
                 875 
                 69 
                 58 
                 147 
                 104 
               
               
                 45 
                 892 
                 900 
                 96 
                 82 
                 455 
                 192 
               
               
                 50 
                 905 
                 923 
                 98 
                 91 
               
               
                 55 
                 916 
                 931 
                 99 
                 93 
               
               
                 60 
                 927 
                 936 
                 131 
                 100 
               
               
                 65 
                 937 
                 954 
                 193 
                 150 
               
               
                   
               
             
          
         
       
     
         [0023]    By observing the measurement taken during this test, the following conclusions can be made: 
         [0000]    
       
         
               
               
             
           
               
                   
               
               
                 Time 
                   
               
               
                 (min.:seg.) 
                 I. OBSERVATION-CONCLUSION 
               
               
                   
               
             
             
               
                 00:00 
                 The test is initiated 
               
               
                 36:00 
                 Carbonization occurs in the unprotected area 
               
               
                 42:05 
                 Failure criteria is reached in the unprotected area (&gt;180° C.) 
               
               
                 46:05 
                 Flames appear in the unprotected area 
               
               
                 65:18 
                 Failure criteria is reached in the protected area (&gt;180° C.) 
               
               
                   
               
             
          
         
       
     
         [0024]    It can be concluded that the use of a membrane of one millimeter thickness, applied directly behind the gypsum board, allows slowing down the time of failure by 23 minutes, which is equivalent to slowing it down by 50% when comparing it to the measurement taken for the area of the unprotected gypsum board. 
       Example 2 
     With Insulation 
       [0025]    In order to directly visualize the protective effect to the fire of the vapor barrier made with laminates of intumescent, self-adhesive, inorganic fire-resistant putty, a wall assembly as shown in  FIG. 5  was constructed for a test, made up of two stiles of radiata pine ( 28 ), on to which two laminates ( 32 ,  33 ) of the inorganic intumescent putty of 1.5 millimeters of thickness were placed; the outer side (not exposed to the fire) was covered with an OSB board ( 29 ), and the inner side (exposed to the fire) was covered with a gypsum board ( 30 ), filling up the interior with fiberglass insulation ( 31 ) of 10 centimeters thickness. In the center of this structural assembly, a gas-powered blowtorch/flamethrower was placed at 30 centimeters distance. After a few minutes, the gypsum board disintegrated, exposing the flame directly on to the intumescent inorganic putty laminate, which then lasted for over six hours without any destruction or flame spread. 
         [0026]    The numbers indicated in the figures have the following meaning:
     1 . Gypsum board.     2 . Polyethylene vapor-barrier of 0.5 mm thickness.     3 . Wooden stile of 2.5 cm thickness and 5 centimeters width.     4 . Termo-acoustic insulation (fibre-glass) of 2.5 cm thickness.     5 . Phenolic slanting wood-board (plywood) of 1.5 cm thickness.     6 . Radiata pine stile of 5 cm thickness and 10 cm width, placed at 40 cm distances between them.     7 . Thermo-acoustic insulation (fibre-glass) of 5 cm thickness.     8 . Phenolic slanting wood-board (plywood) of 1.5 cm thickness.     9 . Vapor barrier.     10 . Outside cladding.     11 . Gypsum board.     12 . Water-vapor barrier with fire-resistant laminate of inorganic intumenscent putty.     13 . Radiata pine stile.     14 . Wooden horizontal frame of radiata pine.     15 . Radiata pine stile.     16 . Wooden horizontal frame of radiata pine.     17 . Radiata pine stile.     18 . Oriented Strand Board (OSB).     19 . Area protected by water vapor barrier with fire-resistant laminate of inorganic intumenscent putty.     20 . Unprotected area.     21 . Position of thermal sensor on testing structure.     22 . Position of thermal sensor on testing structure.     23 . Position of thermal sensor on testing structure.     24 . Position of thermal sensor on testing structure.     25 . Testing furnace.     26 . Position of thermal sensor on testing structure.     27 . Testing structure.     28 . Radiata pine wooden board     29 . Oriented Strand Board (OSB).     30 . Gypsum board.     31 . Fibre-glass insulation.     32 . Water vapor barrier with fire-resistant laminate of inorganic intumenscent putty.   
 
         [0059]    Chile Priority Application Number 519-07, filed on Feb. 27, 2007 is hereby incorporated by reference in its entirety.