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FIELD OF THE DISCLOSURE 
       [0001]    This patent generally pertains to pass-through barriers and, more specifically, pass-through barriers for helping isolate one area from another while preserving the breathable air quality of one of the areas. 
       BACKGROUND 
       [0002]    To protect miners in the event of a mining incident involving the release of toxic gas, smoke or dust, or an incident that reduces the oxygen content of the air; some mines have an underground shelter that provides the miners with a temporary place of refuge isolated from the contaminated air, or air having a low oxygen content. Such shelters often have a sealed door, emergency provisions, and means for providing at least a limited supply of breathable air. The miners can stay in the shelter until they are rescued or until it is safe to leave. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  is a side view of an example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
           [0004]      FIG. 2  is an end view of the example air barrier of  FIG. 1 . 
           [0005]      FIG. 3  is a side view of the example air barrier of  FIG. 1  but showing an individual crawling through the example barrier. 
           [0006]      FIG. 4  is a cross-sectional view of the example air barrier of  FIG. 3 . 
           [0007]      FIG. 5  is a side view similar to  FIG. 1  but showing the example barrier in a deflated state. 
           [0008]      FIG. 6  is a cross-sectional view of the example air barrier of  FIG. 5 . 
           [0009]      FIG. 7  is a perspective close-up view of an example air permeable sidewall material constructed according to the teachings disclosed herein. 
           [0010]      FIG. 8  is a perspective close-up view of another example air permeable sidewall material constructed according to the teachings disclosed herein. 
           [0011]      FIG. 9  is a perspective close-up view of yet another example air permeable sidewall material constructed according to the teachings disclosed herein. 
           [0012]      FIG. 10  is a side view of another example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
           [0013]      FIG. 11  is an end view of the example air barrier of  FIG. 10 . 
           [0014]      FIG. 12  is a side view similar to  FIG. 10  but showing an individual crawling through the example barrier. 
           [0015]      FIG. 13  is a cross-sectional view of the example air barrier of  FIG. 12 . 
           [0016]      FIG. 14  is a side view similar to  FIG. 10  but showing the barrier in a deflated state. 
           [0017]      FIG. 15  is an end view of the example air barrier of  FIG. 14 . 
           [0018]      FIG. 16  is a side view of another example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
           [0019]      FIG. 17  is an end view of the example air barrier of  FIG. 16 . 
           [0020]      FIG. 18  is a side view similar to  FIG. 16  but showing an individual crawling through the barrier. 
           [0021]      FIG. 19  is a cross-sectional view of the example air barrier of  FIG. 18 . 
           [0022]      FIG. 20  is a side view similar to  FIG. 16  but showing the example barrier in a deflated state. 
           [0023]      FIG. 21  is an end view of the example air barrier of  FIG. 20 . 
           [0024]      FIG. 22  is a side view of another example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
           [0025]      FIG. 23  is a side view of another example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
           [0026]      FIG. 24  is a side view of another example inflatable air barrier constructed according to the teachings disclosed herein, wherein the barrier is in a closed, inflated state. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify the same or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. Additionally, several examples have been described throughout this specification. Any features from any example may be included with, a replacement for, or otherwise combined with other features from other examples. 
         [0028]      FIGS. 1-6  show front and side views of an example inflatable air barrier  10  under various conditions. Although barrier  10  can be used in a variety of applications, barrier  10  is particularly suited for providing miners with sealed access to a temporary refuge chamber  12  in case other areas of the mine become contaminated with toxic gas, smoke or dust, for example. 
         [0029]    In examples where refuge chamber  12  already has a sealed door  14 , inflatable barrier  10  can be used for creating an airlock between barrier  10  and the chamber&#39;s door  14 . With barrier  10 , the airlock inhibits toxins from flowing freely into chamber  12  as miners pass through door  14 . Although some contaminants might still enter chamber  12  through door  14  (when open), barrier  10  helps separate a designated more contaminated area  16  of the mine from a designated less contaminated area  18 . The less contaminated area  18  thus provides an airlock or buffer that helps isolate chamber  12  from the more contaminated area  16 . 
         [0030]    In the example illustrated in  FIGS. 1-6 , barrier  10  is installed within a passageway  20  extending between areas  16  and  18 . In this example, passageway  20  is defined by an upper surface  20   a , a lower surface  20   b , a first lateral surface  20   c  and a second lateral surface  20   d . In the illustrated example, barrier  10  comprises at least one inflatable tube  22  (e.g., a first tube  22   a , a second tube  22   b , etc.) to provide quick, easy passage; to sealingly conform to the irregular shape of an individual  24  passing through barrier  10 ; and to avoid relying on mechanisms that might jamb due to corrosion, dust or dirt. 
         [0031]    Tube  22 , in some examples, comprises a sidewall  26  made of a pliable fabric or sheet of material. Examples of such sidewall materials include, but are not limited to, polyester sheeting and polyester fabric. Some example materials are perforated, porous, impervious to gas, or are combinations thereof (e.g., some porous areas and some areas impervious to gas). Some example materials are impregnated or coated with a sealant such as acrylic or polyurethane. Some example materials are uncoated. Some example materials are fire or heat resistant. Some example sidewalls and/or one or more sidewall portions  28  ( FIGS. 10-15 ) are transparent to provide at least some window so individuals can see the conditions on the opposite side of the barrier. 
         [0032]    In the illustrated example, end caps  30  and  32  are attached to opposite ends of tube  22 . End cap  32  is closed while end cap  30  has an air inlet  34  for delivering relatively clean pressurized air  36  into tube  22  when needed. In some examples, a releasable fastener  38  (e.g., a zipper) connects end caps  30  and/or  32  to sidewall  26  so that end caps  30  and/or  32  are removable, interchangeable and reattachable for various installations (e.g., supplying pressurized air  36  from the left or right end, as viewed in  FIG. 1 ). In some examples, the pressurized air  36  is fed through a sidewall inlet of tube  22 , rather than through end cap  30 . 
         [0033]    The shape of end caps  30  and  32  and tube  22  may vary. Some example shapes include, but are not limited to, round, half-round, D-shaped, triangular, elliptical, and/or rectangular. A D-shaped tube that is partially round with a flat mounting side has been found to be particularly stable with minimal shifting. In the illustrated examples, tube  22  is a truncated cylindrical shape (cylindrical but with a flat side), wherein the truncated cylindrical tube has an inflated volume that is at least 50% of a fully cylindrical tube of the same diameter.  FIG. 2 , for example, shows tube  22   a  having a curved surface  40  facing upward and a substantially flat surface  42  facing downward for mounting and sealing to the passageway&#39;s lower surface  20   b.    
         [0034]    Although the actual apparatus for mounting barrier  10  within passageway  20  may vary, in some examples, elastic straps  44  fastened to lateral surfaces  20   c  and  20   d  and threaded through loops  46  on end caps  30  and  32  help hold the ends of barrier  10  to lateral surfaces  20   c  and  20   d  and/or to couple the tubes  22  together. In some examples, the straps  44  may be threaded through or otherwise coupled to one or more brackets to couple the tubes  22  together and/or couple one or more of the tubes  22  to the passageway  22 . The brackets may be coupled to the passageway  22 . Straps  44  being elastic provide some flexibility as barrier  10  distorts under the pressure of individual  24  crawling through barrier  10 . An elastic strap is just one example of a resiliently flexible elongate member. An elastic cord is another example of a resiliently flexible elongate member. In some examples, elastic straps  48  sewn or otherwise attached (e.g., through loops) to tubes  22   a  and  22   b  help stabilize the position of tubes  22   a  and  22   b  relative to each other and/or couple the tubes  22  together. In some examples, the ends of straps  48  are further attached to the passageway&#39;s upper surface  20   a  and lower surface  20   b.    
         [0035]      FIGS. 1-6  show three example operating conditions of barrier  10 .  FIGS. 1 and 2  show tubes  22  in an inflated state and an at rest shape (i.e., a normal shape the barrier assumes when nothing is passing through it). The pressure in tubes  22  creates a pneumatic seal  50  extending longitudinally at the interface between tubes  22   a  and  22   b . The term, “pneumatic seal” means the seal is at least partially actuated by gas pressure. 
         [0036]    When individual  24  crawls through barrier  10  while tubes  22  are inflated, as shown in  FIGS. 3 and 4 , individual  24  distorts tubes  22  from their normal shape ( FIGS. 1 and 2 ) to a manually deformed shape ( FIGS. 3 and 4 ). The tube distortion opens pneumatic seal  50  to create an access opening  52  through which individual  24  crawls. Pressure within tubes  22  presses sidewall  26  conformingly against individual  24  to minimize contaminated gas leakage between sidewall  26  and individual  24 . 
         [0037]    To further minimize contaminated gas from leaking into the less contaminated area  18 , some examples of tube  22  include an air permeable sidewall section  54  facing the more contaminated area  16 . Clean pressurized air  36  within tube  22  bleeds through a plurality of small holes  56  in section  54 . Holes  56  are broadly distributed in two dimensions (e.g., vertically and horizontally) to create a gentle movement of air  58  that pushes contaminated air away from the entrance of barrier  10 . 
         [0038]    It has been discovered that holes  56  should be sufficiently small, uniform, and densely distributed because larger and fewer holes create discrete streams of higher velocity air that tend to draw in lower velocity surrounding air. In some examples, the lower velocity surrounding air comes from the more contaminated area  16 . It is believed that due to the Bernoulli principle, higher velocity streams of air generate local regions of subatmospheric pressure that draws in contaminated gas at atmospheric pressure. 
         [0039]    To create a blanket of slow moving clean air  58  adjacent barrier  10 , some examples of sidewall section  54  have holes  56  with an average hole size that is less than ten times the average material wall thickness  60  of the tube&#39;s sidewall (see  FIGS. 7-9 ). The term, “hole size” is defined herein as the diameter of a circle having the same area as the open area of the hole. Holes  56  (e.g., holes  56   a ,  56   b  and  56   c ) can be any shape, examples of which include, but are not limited to, round ( FIG. 7 ), slits ( FIG. 8 ), fabric pores ( FIG. 9 ). In some examples, for broad distribution, holes  56  are spaced apart with an average spaced-apart distance (e.g., distance  62   a ,  62   b  or  62   c ) that is less than fifty times the average material wall thickness  60  of the tube&#39;s sidewall. The spaced-apart distance is with respect to the center of one hole to the center of an adjacent hole. In some examples, holes  56  have a distribution of at least 10 holes per square-centimeter. 
         [0040]    When barrier  10  is not in active use, tubes  22  are left in an unpressurized deflated state, as shown in  FIGS. 5 and 6 . In some examples, tubes  22  in the deflated state are relatively limp with an opening  64  between tubes  22   a  and  22   b.    
         [0041]    In the example of  FIGS. 10-15 , however, opening  64  is eliminated even when tubes  22  are in the deflated state, as shown in  FIGS. 14 and 15 . Eliminating opening  64  helps keep area  18  relatively clean before inflating tubes  22 . To achieve such results, an example inflatable barrier  66  includes a resiliently compressible foam body  68  installed within tube  22   a . In some examples, the foam body  68  has a substantially triangular cross-section to enable an end of the foam body  68  adjacent the pneumatic seal  50  to be relatively flexible. In addition to eliminating opening  64 , foam body  68  displaces a significant amount of air volume within tube  22 , so less pressurized air  36  is required to inflate tube  22 . This benefit is particularly important in a compromised mine where air is a very precious commodity. Also, with tube  22  requiring less air to fully inflate, tube  22  can be inflated in less time, which is usually important during emergencies. Foam body  68  is one example of a resilient member engaging first tube  22   a  and being manually movable to a manually deflected state ( FIGS. 12 and 13 ) and a restored state ( FIGS. 10 ,  11 ,  14  and  15 ). 
         [0042]    When tubes  22  are deflated, foam body  68  holds tube  22   a  up against tube  22   b  to establish a mechanical seal  70  between tubes  22   a  and  22   b . The term, “mechanical seal” refers to a seal that can be held substantially closed without having to rely on pneumatic pressure. In some examples, pneumatic seal  50  and mechanical seal  70  close at the same interface between tubes  22   a  and  22   b . In such examples, pneumatic seal  50  and mechanical seal  70  open and close as one sealing unit. When tubes  22  are in their inflated state and/or normal shape, as shown in  FIGS. 10 and 11 , both pneumatic seal  50  and mechanical seal  70  are closed. 
         [0043]    When individual  24  crawls through barrier  66  while tubes  22  are inflated, as shown in  FIGS. 12 and 13 , individual  24  readily compresses foam body  68  from its restored state ( FIGS. 10 and 11 ) to its deflected state ( FIGS. 12 and 13 ) and distorts tubes  22  from their normal shape and/or inflated state ( FIGS. 10 and 11 ) to a manually deformed shape ( FIGS. 12 and 13 ). The compression of foam body  68  and the distortion of tubes  22  open both mechanical seal  70  and pneumatic seal  50  to create access opening  52  through which individual  24  crawls. After individual  24  has passed through barrier  66 , as shown in  FIGS. 14 and 15 , foam body  68  resiliently returns to its restored state to close mechanical seal  70  even if tubes  22  are deflated. 
         [0044]    In some examples, foam body  68  has a strap anchor  72  and cavities  74  and  76 . Strap anchor  72  helps hold foam body  68  in the proper position within tube  22   a . Cavities  74  and  76  are holes and/or notches that reduce the force need to compress foam body  68  and allow for inflation of tube  22  without additional resistance to airflow. 
         [0045]    In some examples, to enhance sealing between tubes  22   a  and  22   b , an example inflatable barrier  78  includes a magnet  80  (e.g., a magnetic strip) and/or an elastic strap  82  extending lengthwise along the sealing interface between tubes  22   a  and  22   b . Magnet  80  is schematically illustrated to represent any two strips or pieces that are magnetically attracted to each other, wherein one piece  80   a  is sewn or otherwise attached to tube  22   a , and another piece  80   b  is sewn or otherwise attached to tube  22   b.    
         [0046]    Except for the addition of magnet  80  and strap  82 , barriers  78  and  10  are identical in structure and function with  FIGS. 16-21  corresponding to  FIGS. 1-6 , respectively. Barrier  78  with magnet  80  (with or without strap  82 ) provides a tight seal between tubes  22   a  and  22   b  even when they are deflated, as shown in  FIGS. 20-21 . If contact between the tubes  22   a  and  22   b  is broken, the tubes  22   a  and  22   b  will need to be re-inflated to re-seal the interface. 
         [0047]    Elastic strap  82  is an example of a resilient member engaging the interior or exterior of tube  22   a  and being manually movable to a manually deflected state ( FIGS. 18 and 19 ) and a restored state ( FIGS. 16 ,  17 ,  20  and  21 ). An elastic cord is another example of such a resilient member. In some examples, opposite ends of elastic strap  82  are attached to lateral surfaces  20   c  and  20   d  and the medial section of strap  82  is sewn or otherwise attached to tube  22   a . This gives tube  22   a  some support when tube  22   a  is deflated, thus strap  82  provides a function similar to that of foam body  68 . Strap  82  can be used with or without magnet  80 . 
         [0048]    Although various examples of inflatable air barriers are illustrated as comprising two generally horizontal inflatable tubes, other example barriers have any number of tubes in other orientations. For instance,  FIG. 22  shows a single horizontal tube  84 ,  FIG. 23  shows four horizontal tubes  86  that meet generally at the center of passageway  20 , and  FIG. 24  shows two vertical tubes  88 . One or more features used in some example barriers disclosed herein can be directly used or readily adapted for use in other example barriers. 
         [0049]    As set forth herein, an example inflatable air barrier for a passageway extending between a first area and a second area, the passageway being defined by an upper surface, a lower surface, a first lateral surface and a second lateral surface. The inflatable air barrier includes a first tube having an inflated state and a deflated state. The first tube is manually deformable in the inflated state from a normal shape to a manually deformed shape. The first tube is to provide a pneumatic seal within the passageway when the first tube is in the inflated state while in the normal shape. The pneumatic seal is to provide an access opening through the passageway when the first tube is in the inflated state while in the manually deformed shape. The first tube in the deflated state is substantially unpressurized. The first tube includes a first sidewall section to face the first area. The first sidewall section includes an air permeable material having a plurality of holes distributed in two dimensions across a surface of the first sidewall section. 
         [0050]    In some examples, the first tube includes a second sidewall section to face the second area. In some examples, the second sidewall section is substantially impermeable to air. In some examples, the first sidewall section includes at least twenty percent of the first tube. In some examples, the inflatable air barrier also includes a second tube substantially similar to the first tube. The pneumatic seal is to be defined between the first tube and the second tube, and the access opening, when present, is between the first tube and the second tube. In some examples, the permeable material has a material wall thickness and the plurality of holes are spaced apart with an average spaced apart distance of less than fifty times the material wall thickness. In some examples, the inflatable air barrier also includes a magnet to form the pneumatic seal. In some examples, the first tube includes a curved surface facing upward and a substantially flat surface facing downward. In some examples, the air permeable material has a material wall thickness, and an average hole size of the plurality of holes divided by the material wall thickness is less than ten to broadly disperse air out from within the first tube into the designated more contaminated area. 
         [0051]    Another example inflatable air barrier for a passageway extending between a first area and a second area, the passageway being defined by an upper surface, a lower surface, a first lateral surface and a second lateral surface. The inflatable air barrier includes a pneumatic seal within the passageway. The pneumatic seal is selectively opened and closed. A mechanical seal is within the passageway. The mechanical seal is selectively opened and closed. A first tube has an inflated state and a deflated state. The first tube in the inflated state is manually deformable from a rest shape to a manually deformed shape. The first tube provides and closes the pneumatic seal within the passageway when the first tube is in the inflated state while in the rest shape. The first tube opens the pneumatic seal and provides an access opening through the passageway when the first tube is in the inflated state while in the manually deformed shape. The first tube is substantially unpressurized in the deflated state. A resilient member engages the first tube. The resilient member is manually movable between a restored state and a deflected state. The resilient member in the restored state supports the first tube to provide and close the mechanical seal within the passageway. The resilient member in the deflected state yields with the first tube to open the mechanical seal within the passageway. 
         [0052]    In some examples, the pneumatic seal and the mechanical seal are to open and close as one sealing unit. In some examples, the resilient member includes a resiliently compressible foam body disposed within the first tube. In some examples, the inflatable air barrier also includes an anchor fastening the resiliently compressible foam body to the first tube. In some examples, the resiliently compressible foam body defines a cavity. In some examples, the resiliently compressible foam body is elongate in a longitudinal direction and has a generally triangular cross-section perpendicular to the longitudinal direction. In some examples, the resilient member includes a resiliently flexible elongate member connected to the first tube. In some examples, the inflatable air barrier also includes a second tube substantially similar to the first tube. The pneumatic seal is between the first tube and the second tube, and the access opening, when present, is between the first tube and the second tube. A resiliently flexible elongate member connects the first tube to the second tube. In some examples, the resiliently flexible elongate member lies between the first tube and at least one of the first area and the second area. In some examples, the resiliently flexible elongate member lies between an axial end of the first tube and at least one of the surfaces of the passageway. In some examples, the inflatable air barrier also includes a second tube substantially similar to the first tube. The pneumatic seal is between the first tube and the second tube, and the access opening, when present, is between the first tube and the second tube. A resiliently flexible elongate member is connected to the first tube and lying proximate and substantially parallel to the pneumatic seal. In some examples, at least one of the mechanical seal or the pneumatic seal includes a magnet. In some examples, the first tube includes a curved surface and a substantially flat surface. The flat surface is to be adjacent one of the surfaces of the passageway. 
         [0053]    Another example inflatable air barrier for a passageway extending between a designated more contaminated area and a designated less contaminated area, the passageway being defined by an upper surface, a lower surface, a first lateral surface and a second lateral surface. The inflatable air barrier includes a first body and a second body defining a pneumatic seal within the passageway. The pneumatic seal is selectively opened and closed. Each of the first body and the second body have an inflated state and a deflated state. The first body is manually deformable when in the inflated state from a first shape to a manually deformed shape. The first body cooperates with the second body to close the pneumatic seal within the passageway when the first body is in the inflated state while in the first shape. The first body opening the pneumatic seal between the first body and the second body when the first body is in the inflated state while in the manually deformed shape. The first body is substantially unpressurized in the deflated state. A resiliently flexible elongate member is attached to the first body. 
         [0054]    In some examples, the second body is substantially similar to the first body. The resiliently flexible elongate member is attached to both the first body and the second body. In some examples, the resiliently flexible elongate member lies between the first body and at least one of the first area or the second area. In some examples, the resiliently flexible elongate member lies between an axial end of the first body and at least one of the surfaces of the passageway. In some examples, the resiliently flexible elongate member lies proximate and substantially parallel to the pneumatic seal. In some examples, inflatable air barrier also includes a magnet to urge the pneumatic seal to a closed position. 
         [0055]    Another example inflatable air barrier for a passageway extending between first area and a second area. The inflatable air barrier includes a pneumatic seal within the passageway. The pneumatic seal is selectively opened and closed. A body includes a tubular sidewall interposed between a first end cap and a second end cap. The body has an inflated state and a deflated state. The body in the inflated state is manually deformable from a normal shape to a manually deformed shape. The body defines the pneumatic seal within the passageway between the first area and the second area. The body is to enable opening the pneumatic seal to provide an access opening when the body is in the inflated state while in the manually deformed. The tube is substantially unpressurized in the deflated state. At least one of the first end cap or the second end cap being removable and reattachable to the tubular sidewall. 
         [0056]    In some examples, at least one of the first end cap or the second end cap defines an air inlet, and the first end cap and the second end cap are interchangeable. In some examples, the inflatable air barrier also includes a releasable fastener connecting at least one of the first end cap or the second end cap to the tubular sidewall. In some examples, the releasable fastener includes a zipper. In some examples, at least one of the first end cap or the second end cap are to seal under pneumatic pressure against at least one of the surfaces of the passageway. In some examples, the inflatable air barrier also includes a resiliently flexible elongate member connecting at least one of the first end cap or the second end cap to at least one of the upper surface, the lower surface, the first lateral surface or the second lateral surface. In some examples, the pneumatic seal includes a magnet. 
         [0057]    Another example inflatable air barrier for a passageway extending between a designated more contaminated area and a designated less contaminated area, the passageway being defined by an upper surface, a lower surface, a first lateral surface and a second lateral surface. The inflatable air barrier includes a pneumatic seal within the passageway. The pneumatic seal is selectively opened and closed. A tube has an inflated state and a deflated state. The tube in the inflated state is manually deformable from a normal shape to a manually deformed shape. The tube provides and closes the pneumatic seal within the passageway when the tube is in the inflated state while in the normal shape. The tube opens the pneumatic seal to provide an access opening when the tube is in the inflated state while in the manually deformed shape. The tube is substantially unpressurized in the deflated state. A transparent section is on the tube. 
         [0058]    Another example inflatable air barrier for a passageway extending between a designated more contaminated area and a designated less contaminated area, the passageway being defined by an upper surface, a lower surface, a first lateral surface and a second lateral surface. The inflatable air barrier includes a pneumatic seal within the passageway. The pneumatic seal is selectively opened and closed. A tube has an inflated state and a deflated state. The tube in the inflated state is manually deformable from a normal shape to a manually deformed shape. The tube provides and closes the pneumatic seal within the passageway when the tube is in the inflated state while in the normal shape. The tube opens the pneumatic seal and provides an access opening when the tube is in the inflated state while in the manually deformed shape. The tube substantially is unpressurized in the deflated state and a magnet at the pneumatic seal. 
         [0059]    Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of the coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.

Summary:
Example inflatable air barriers are disclosed herein. Some example barriers disclosed herein include one or more inflatable tubes for maintaining a sealed airlock leading to an underground shelter. Such shelters provide miners with temporary refuge in the event of a mining incident involving the release of contaminated air. Some example barriers disclosed herein include one or more of the following: an inflatable tube with an air permeable section, a resiliently compressible foam body or other resilient member for supporting a deflated tube, a magnet for providing a secure seal, an inflatable tube with interchangeable end caps, elastic bands for securing the position of an inflatable tube, or an inflatable tube with one or more windows.