BACKGROUND OF THE INVENTION  
         [0001]    A. Field of the Invention  
           [0002]    The present invention relates to methods and apparatus for facilitating evacuation of people from burning buildings. More particularly, the invention relates to a portable apparatus which is moved into sealing contact with a hallway opening or doorway of a burning building to block heat, smoke and noxious combustion gases produced by a fire located upstream of the opening from passing into areas of the building downstream from the hallway opening, while enabling people to transit safely through the apparatus to exit the building.  
           [0003]    B. Description of Background Art  
           [0004]    Fires occurring in buildings occupied by people are often initially confined to a relatively small area, enabling occupants to safely escape, provided the building is equipped with suitable alarm systems and evacuation routes. However, even if a building fire is initially confined to a relatively small area, and relatively slow moving, smoke, noxious combustion products and heat produced by the fire can travel relatively quickly from the fire to other parts of the building. Even relatively small amounts of smoke can obscure a person&#39;s vision and impede his or her safe evacuation from the building. Of even greater concern is the fact that inhalation of sufficient quantities of smoke, gaseous combustion products, or even hot air can and frequently does result in death. Accordingly, when a fire breaks out in a building, it is desirable to confine products of the fire as well as the fire itself to its area of origin, to facilitate safe evacuation of the building. Therefore, buildings occupied by people are sometimes provided with relatively large and heavy fire doors that are manually or automatically closed when a fire breaks out in a building to inhibit the spread of a fire, and to inhibit heat, smoke, and noxious gases produced by the fire from rapidly diffusing throughout the building. Besides being relatively difficult to open by individuals who do not have great physical strength, fire doors undesirably pose no barrier to heat, smoke, and noxious combustion gases when opened by an individual to exit through the doorway.  
           [0005]    The present inventor is aware of two prior art systems which use water to inhibit movement of heat, smoke and hot gases through a tunnel or other occupied structure, thus facilitating safe evacuation of humans from the structure. Thus, Hattori, U.S. Pat. No. 4,077,474, Mar. 7, 1978, Flame And Smoke Shutoff System, discloses a flame and smoke shutoff system which uses a curtain made of flexible, non-flammable material. The curtain drops down from the ceiling to a floor of a building passageway in the event of a fire, and a mixture of water and a bubbling agent is made to flow down the curtain to check the spread of flame and smoke, while allowing individuals to raise the curtain temporarily and step through to escape. Mühlenbruck, in PCT Publication No. WO0180954, published Nov. 1, 2001, discloses a system for facilitating escape from a tunnel which might otherwise be filled with smoke and hot gases, the system utilizing a series of water mist curtains sprayed from the tunnel ceiling.  
           [0006]    The present invention was conceived of to provide a life-saving fire exit apparatus and method for use in buildings which provides a positive barrier to smoke and hot gases emanating from a fire in a building, while enabling easy and safe transit of individuals through the barrier to smoke-free regions of the building, thereby facilitating safe evacuation of the building.  
         OBJECTS OF THE INVENTION  
         [0007]    An object of the present invention is to provide a life saving fire exit apparatus for facilitating evacuation of humans from a burning building, the apparatus including a barrier for confining smoke and hot gases to the locality of a fire, while permitting ready egress of individuals through the barrier.  
           [0008]    Another object of the invention is to provide a life saving fire exit apparatus for buildings which includes a water trap for smoke and hot gases which permits ready egress through the trap by an individual to evacuate the building.  
           [0009]    Another object of the invention is to provide a life saving fire exit apparatus for buildings which includes a water-filled pool, and a wall or baffle which protrudes downwardly from a building ceiling, the baffle having a lower transverse disposed edge below the surface of water in the pool to thereby form with the water a smoke impervious, air-lock type barrier, and entrance and exit steps to the pool which facilitate an individual&#39;s stepping into the pool, ducking his or her head into the water beneath the lower edge of the baffle, stepping under the baffle and stepping out of the pool to thereby enter relatively smoke-free areas and safely exit the building.  
           [0010]    Another object of the invention is to provide methods for blocking smoke and hot gases emanating from a fire within a building from traveling through a building passageway, while enabling individuals to pass readily through the passageway, the method comprising the steps of positioning a pool of water in an exit passageway of a building, positioning a vertically disposed baffle transversely across the passageway in hermetically sealing contact with water in the pool and adjacent passageway walls, and providing means such as entrance and exit stairways or stepladders for facilitating an individual&#39;s entering the pool, ducking his or her head into the water beneath one side of the baffle, moving underneath the baffle, and exiting from the pool on the opposite side of the baffle.  
           [0011]    Various other objects and advantages of the present invention, and its most novel features, will become apparent to those skilled in the art by perusing the accompanying specification, drawings and claims.  
           [0012]    It is to be understood that although the invention disclosed herein is fully capable of achieving the objects and providing the advantages described, the characteristics of the invention described herein are merely illustrative of the preferred embodiments. Accordingly, do not intend that the scope of my exclusive rights and privileges in the invention be limited to details of the embodiments described. I do intend that equivalents, adaptations and modifications of the invention reasonably inferable from the description contained herein be included within the scope of the invention as defined by the appended claims.  
         SUMMARY OF THE INVENTION  
         [0013]    Briefly stated, the present invention comprehends a life saving fire exit apparatus and method which facilitates the safe evacuation of a building in which a fire producing heat, smoke and noxious gases has broken out.  
           [0014]    A life saving fire exit apparatus according to the present invention includes a portable enclosure which contains shallow, generally rectangularly shaped open-top tank similar to a wading pool or spa, which contains water, and a vertically oriented baffle disposed transversely across the width of the tank which has a lower edge immersed beneath the surface of water in the tank, the baffle extending to the ceiling of the enclosure. The baffle spans the width of the enclosure, and is in air-tight contact with the side walls and ceiling thereof. Also, the enclosure includes an entrance opening hermetically sealable to a building passageway opening such as a hallway opening, when the enclosure is moved into position adjacent to the opening. The enclosure contains a short entrance stairway located on an entrance side of the pool, and a short exit stairway located at the opposite side of the pool, on the other side of the baffle.  
           [0015]    The enclosure has a peripheral seal around the entrance opening thereof, which, when positioned in hermetically sealing contact with a hallway opening, cooperates with water in the tank and the baffle immersed in the water to form an air-lock type barrier which blocks the passage of smoke and noxious gases through the hallway opening. As is explained below, the barrier is not breached by an individual transiting through the barrier.  
           [0016]    In a main embodiment of the life saving fire exit apparatus according to the present invention, the vertically disposed baffle has the form of a V-shaped trough or channel made of a rigid material such as a stainless steel plate bent at an acute angle to form a pair of side panels, the lower vertex portion of which contains water maintained at the same level as that in the pool. A pair of longitudinally aligned, fire-proof windows, one in each of the side panels of the baffle, enable individuals on either side of the baffle to visually assess conditions on the other side thereof. In an alternate embodiment of the apparatus, the solid baffle is replaced by one or more curtains of water flowing from one or more manifolds disposed transversely beneath the ceiling of the enclosure, water being pumped up to the manifold from a step-through holding tank and flowing back into the tank in a closed loop, re-circulating system. In that embodiment, the water level in. the tank can be substantially lower than that of the solid baffle embodiment, thus, the tank can be much shallower, and not require entrance or exit steps.  
           [0017]    According to another aspect of the invention, a method of inhibiting wide dispersal of smoke and noxious gases from a fire in a building, while enabling people to evacuate the building comprises positioning a pool of water within a passageway within the building, positioning a baffle in hermetically sealing contact with side walls and ceiling of the passageway, the baffle being disposed vertically downwards from the ceiling with the lower edge of the baffle immersed beneath the surface of water in the pool, and providing an access path through the pool which enables an individual to readily step into the pool, duck his or her head into the water beneath the lower edge of the baffle, walk through the water underneath the baffle, and step out of the pool to a smoke-free evacuation route from the building. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a perspective view of a life saving fire exit device according to the present invention.  
         [0019]    [0019]FIG. 2 is a view similar to that of FIG. 1, but showing the device containing water.  
         [0020]    [0020]FIG. 3 is a diagrammatic view showing the device of FIG. 1 positioned for use in a building.  
         [0021]    [0021]FIG. 4 is a perspective view showing the device of FIG. 1 in a storage position and ready for movement into an operative position in front of a hallway opening in a building.  
         [0022]    [0022]FIG. 5A is a sectional view showing the device of FIG. 4 taken in the direction  5 A- 5 A, and showing the device positioned in front of a hallway opening.  
         [0023]    [0023]FIG. 5B is a view similar to that of FIG. 5B, showing how the device of FIG. 5A is moved into hermetically sealing contact with a frame installed around the hallway opening, to thereby block smoke, noxious gaseous combustion products, and heat from passing through the opening, while enabling humans to exit from the hallway through the device.  
         [0024]    [0024]FIGS. 6A through 6C illustrates an adult exiting from a smoke-filled area through the device of FIG. 1.  
         [0025]    [0025]FIGS. 7A through 7C illustrates a child exiting from a smoke-filled area through the device of FIG. 1.  
         [0026]    [0026]FIG. 8 is a sectional view of the device of FIGS. 6 and 7, showing an adult and child emerging through the device.  
         [0027]    [0027]FIG. 9 is a diagrammatic view of a modification of the device of FIG. 1 suitable for use by a person in a wheel chair.  
         [0028]    [0028]FIG. 10 is a transverse sectional view showing a person in a wheel chair using the device of FIG. 9.  
         [0029]    [0029]FIG. 11 is a diagrammatic view of another modification of the device of FIG. 1 suitable for use by a person in a wheel chair. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    [0030]FIGS. 1 and 2 are perspective, partly schematic views of a basic embodiment of a life saving fire exit apparatus according to the present invention. FIG. 3 is a schematic view showing where the apparatus of FIGS. 1 and 2 is positioned within a building. FIGS. 4 and 5 illustrate details of deploying the apparatus of FIGS. 1 and 2 adjacent to a hallway opening within a building. FIGS.  6 - 8  illustrate the manner of using the apparatus of FIGS. 1 and 2.  
         [0031]    Referring first to FIG. 1, a life saving fire exit apparatus  20  according to the present invention may be seen to include a generally rectangularly-shaped, hollow enclosure  21 , which has a longitudinally elongated, rectangularly-shaped base panel  22 , upstanding front and rear vertical side panels  23 ,  24 , a roof panel  25  parallel to base panel  22 , and left and right vertically disposed rectangularly-shaped entrance and exit openings  26 ,  27 , respectively. Apparatus  20  includes a vertically oriented baffle  28  which is located midway between entrance and exit openings  26 ,  27 , and which is disposed transversely between front and rear wall panels  23 ,  24  of enclosure  21 . As shown in FIG. 1, baffle  28  spans the distance between front and rear wall panels  23 ,  24 , and is joined to those panels, as well as roof panel  25 , in air-tight tight junctions therewith.  
         [0032]    Referring still to FIGS. 1 and 2, it may be seen that enclosure  21  of fire saving exit apparatus  20  includes above and adjacent to base panel  22  thereof an upwardly concave portion  29 , which comprises a tank or reservoir that is adapted to hold a pool of water  30 , as shown in FIG. 2. As shown in FIGS. 1 and 2, base panel  22  and front and rear side panels  23 ,  24  form bottom, front and rear sides, respectively, of tank  29 .  
         [0033]    The left side of tank  29  is bounded by the longitudinally inwardly located, descending half  32  of a left-hand, entrance up-and-down staircase  31 . The latter has a longitudinally outwardly located ascending half  33  shaped symmetrically to descending, inner half  33 .  
         [0034]    Similarly, the right side of tank  29  is bounded by a longitudinally inwardly located, ascending half  35  of a right-hand, exit up-and-down staircase  34 . The latter has a longitudinally outwardly located, descending half  36  shaped symmetrically to ascending inner half  35 .  
         [0035]    As shown in FIGS. 1 and 2, entrance and exit up-and-down staircases  31 ,  34  are each comprised of a plurality of fore-and-aft elongated, rectangularly shaped steps  37  which are disposed perpendicularly between front and rear side panels  23 ,  24  of enclosure  21 . Entrance and exit staircases  31 ,  34  each has an uppermost, middle step  38 I,  38 O, respectively, that have upper flat horizontally disposed, co-planar surfaces  39 I,  39 O, respectively. As shown in FIG. 2, tank portion  29  of enclosure is filled with water  30  to a level L below surfaces  39 I,  39 O, prior to using apparatus  20 .  
         [0036]    As shown in FIGS. 2 and 3, baffle  28  has a lower edge  40  which is immersed beneath the surface of water  30  in tank  29 . Also, baffle  28  has a front side edge  41  which is joined to front side panel  23  of enclosure  21 , a rear side edge  42  joined to rear side panel  24 , and an upper side edge  43  joined to roof panel  25 , in hermetically sealing contact with the respective side panels. With this construction, as shown in FIG. 3, water  30  in tank  29  forms a barrier or water trap which blocks heat, smoke  45 , and noxious gases from a fire  44  located to left of entrance opening  26  of enclosure  21  from passing through the barrier to exit opening  27  of the enclosure. As will be described in greater detail below, with enclosure  20  arranged in a building passageway  46  as shown in FIG. 3, individuals in a smoke-filled region  47  of the passageway may transit through tank  29  under baffle  28  to a smoke-free region  48  of the passageway, proceed safely down stairs  49 , and out through exit  51  of building  50 , as indicated by the series of arrows. As shown in FIG. 3, the exact shape of baffle  28  is not critical, provided that it has upper, front and rear sides which make an air-tight seal with a building passageway while the lower edge wall of the baffle is submerged in water  30  in tank  29  to block smoke, noxious gases and heat from traveling past the baffle.  
         [0037]    Preferably, as shown in FIGS.  1 - 3 , baffle  28  has in longitudinal section a V-shape. Baffle  28  is made of a heat resistant material. In a preferred embodiment shown in FIGS. 1 and 2, baffle  28  is made of a longitudinally elongated rectangular sheet of stainless plate which is bent at a transverse center line thereof to form left and right panels  52  and  53  which angle upwardly and outwardly from a lower, vertex edge  40  which is disposed perpendicularly between front and rear side wall panels  23 ,  24  of enclosure  21 . Thus constructed, left and right panels  52  and  53  of baffle  28  form between inner facing surfaces thereof and inner facing surfaces of front and rear panels  23 ,  24 , a V-shaped trough  55  adapted to contain water  56 , as shown in FIGS. 2 and 3. Preferably, left and right panels  52 ,  53  of baffle  28  are fitted with a pair of longitudinally aligned, rectangularly-shaped windows  57 ,  58 , which are made of a visibly transparent, fireproof glass.  
         [0038]    As shown in FIG. 1, enclosure  21  of apparatus  20  preferably includes means for automatically filling tank  29  and baffle trough  55  with water, preferably to levels which are approximately the same and at a height of slightly less than one foot below entrance and exit platform surfaces  39 I,  39 O. Thus, as shown in FIGS. 1 and 2, apparatus  20  preferably includes one or more water supply pipes or tubes  59 ,  60 , which are connected at inlet ends thereof to a source of water such as a building water supply pipe. Outlet ends of pipes  59 ,  60  are connected through float valves  61 ,  62  within tank  29  and trough  55 , respectively, the valves opening to admit water into the respective reservoirs, and closing when the water level therein reaches predetermined levels.  
         [0039]    As shown in FIGS. 1, 2 and  8 , tank  29  of enclosure  21  preferably is partitioned into side-by-side channels of different depths, to facilitate use of the apparatus by both adults and children. Thus, as shown in FIGS. 1 and 8, tank  29  preferably has a deep, adult channel  63  provided with a relatively deep floor panel  64 , and a shallow, child&#39;s channel  65  which has a shallow floor panel  66 . Preferably, deep and shallow channels  63 ,  65  are separated by a longitudinally disposed vertical separator panel  67  made of a transparent material, e.g., a polycarbonate or acrylic plastic sheet.  
         [0040]    [0040]FIGS. 3, 6, and  7  illustrate how adults and children, respectively, may use apparatus  20  to exit from a smoke-filled region to a relatively smoke-free region of a building. Thus, with apparatus  20  installed in hermetically sealing contact with the floors, walls and ceiling of a building passageway  46 , as shown in FIG. 3, an adult or child walks up the ascending steps  33  of entrance up/down staircase  31 , and pauses on upper surface  39 I of uppermost, middle step  38 , as shown in FIGS. 6A, 7A. The adult or child then walks down descending portion  32  of entrance staircase  31 , into water  30  in tank  29 , and stands on the floor panel of the tank. Then, as shown in FIGS. 6B, 7B, the adult or child ducks his head beneath the surface of water  30 , sufficiently deep to clear the lower edge wall  40  of baffle  28 , and walks forward on the floor panel of the tank towards exit stairway  34 . Next, as shown in FIGS. 6C and 7C, the child or adult stands erect, with his or her head above the surface of water  30  in tank  29 , walks forward towards exit stairway  34 , up the ascending steps  35  and down the descending steps  36  thereof, and walks away from apparatus  20  to exit safely from a smoke-filled region of the building to a relatively smoke-free region, thus facilitating his or her safe exit from the building.  
         [0041]    In a preferred embodiment of a life saving fire exit apparatus according to the present invention, the apparatus is so constructed as to be readily movable from a storage position, as shown in solid lines in FIG. 4, to an operable position in hermetically sealing contact with an opening in a building passageway, as shown by dashed lines in FIG. 4. Thus, as shown in FIGS. 1, 2 and  4 , apparatus  20  preferably includes a plurality of rollers or casters  68  which rollably support enclosure  21 . Also, as may be seen best by referring to FIGS.  4  and  5 , apparatus  20  preferably has a peripheral sealing member  69  which enables enclosure  21  to be coupled to an opening  71  of a building passageway in a relatively air-tight seal. As shown in FIGS. 1 and 5, enclosure peripheral sealing member  69  is a rectangular ring-shaped structure which concentrically borders rectangularly-shaped entrance opening  26  of enclosure  21 . Sealing member  69  is comprised of upper and lower straight horizontally disposed legs  72 ,  73 , and front and rear vertically disposed straight legs  74 ,  75 . As shown in FIG. 5, each leg of rectangular ring-shaped peripheral sealing member  69  has a right triangular cross-sectional shape, with the hypotenuse of each member angled outwardly from enclosure  21  and towards a longitudinal center line of opening  26 ; thus sealing member  69  has a beveled outer mating surface  76 . As shown in FIG. 5, beveled outer mating surface  76  of enclosure sealing member  69  is confronted by a similarly shaped beveled surface  78  of a passageway peripheral sealing member  77  installed in opening  71  of passageway  70 .  
         [0042]    Both enclosure peripheral sealing ring  69  and passageway opening peripheral sealing ring  77  are made of a material which is somewhat flexible and resilient but heat resistant, such as thin gauge stainless steel. Thus, when enclosure  21  of apparatus  20  is moved laterally into position in front of a passageway opening  71 , as shown in FIG. 4, and then longitudinally inwardly towards the opening, as shown in FIGS. 5A and 5B, resilient contact of beveled surfaces  76  and  78  of sealing members  69  and  77  form an air-tight, resilient, heat resistant seal.  
         [0043]    In a modification of life saving fire exit apparatus  20  described above, solid baffle  28  is replaced partially or entirely by one or more curtains of water dispensed transversely across enclosure  21 , and flowing downwardly from manifolds attached to ceiling panel  25  into tank  29 . In this modification, a pump is preferably provided to recirculate water from tank  29  to the manifolds. With this arrangement, tank  29  can be substantially shallower, and entrance and exit stairways dispensed with.  
         [0044]    The fire life saving fire exit apparatus and methods according to the present invention may also be used advantageously by fire fighters as a portal for entering as well as leaving smoke-filled regions of a building.  
         [0045]    [0045]FIGS. 9 and 10 illustrate a modification of a life saving fire exit apparatus according to the present invention, which is suitable for use by a person in a wheel chair.  
         [0046]    As shown in FIGS. 9 and 10, modified life saving fire exit device  120  includes a generally rectangularly-shaped, open-top tank  129  which has a rectangularly-shaped base panel  122 , front and rear vertical side panels  123 ,  124 , and left and right vertical end panels  126 ,  127 , respectively. As in the basic embodiment  20 , apparatus  120  includes an enclosure (not shown) and a hollow, V-shaped baffle  122  which protrudes downwardly from a roof panel (not shown) of the enclosure, the baffle having a lower edge  140  which is immersed below the surface of water  130  contained in tank  129 . Apparatus  120  also includes a rectangularly-shaped platform  131  which is supported by a plurality of vertically disposed linear actuator cylinders  132  which protrude upwardly from the upper surface of base panel  122 . Actuator cylinders  132  are energizable by a hydraulic or pneumatic pressure source (not shown) to alternately raise platform  131 , as shown in FIG. 10, or lower it, as shown in FIG. 9.  
         [0047]    Apparatus  120  also includes a mechanism for raising a wheelchair  133  occupied by a person  134  from a building floor  135  on which tank  129  resides to a height above that of the upper edges  136 ,  137  of end panels  126 ,  127 , lowering the wheelchair into water  130 , raising wheelchair  134  above upper edge  137  of right-hand end panel  137  of tank  129 , after it has transited underneath baffle  128 , and lowering the wheelchair back to floor level. One such mechanism for performing the aforementioned actions comprises a pair of external platforms raised and lowered by linear actuator cylinders, similar in structure and function to platform  131  and cylinders  132  described above. In this implementation, one such external platform is located adjacent to the outside of left-hand tank end panel  126 , while the other exterior platform is located adjacent to the outside of right-hand tank panel  127 .  
         [0048]    [0048]FIG. 11 illustrates an alternate mechanism  138  for facilitating movement of a wheelchair  133  and occupant  134  through tank  129 . Mechanism  138  includes a longitudinally disposed trolley track  140  which rollably supports a trolley  141 , the track being positioned above and parallel to a longitudinal center line of tank  129 . A platform  142  is suspended from trolley  141  by a variable length, motor-driven cable and pulley mechanism  143 . Flexible elastic cords  144  are in turn suspended from the corners of platform  142 , each cord having at the lower end thereof a hook  144  adapted to engage a structural member of wheelchair  133 .  
         [0049]    Mechanism  138  includes a flexible multi-conductor electrical cable  145  which is suspended from trolley  141 , and in turn suspends at the lower end of the cable an electrical control box  147 . Control box  147  contains controls  148  which are used to operate a trolley drive motor (not shown) and an elevator motor (not shown) for operating cable lift mechanism  143 . To use mechanism  138  a person  134  in wheelchair  133  first engages structural members of the wheelchair with hooks  145 , with trolley  141  located on the left-hand side of left end panel  126  of tank  129 . Next, person  134  operates controls  148  on control box  147  to energize lifting mechanism  143 , thereby elevating the lower edges of the wheelchair wheels  150  above edge  136  of end panel  126 . Controls  148  of control box  147  are then actuated to cause trolley  141  to move longitudinally to a location between left end panel  126  and baffle  128 , and lower the wheelchair into tank  129  onto platform  131 , whereupon platform  131  is lowered, and trolley  141  then used to translate the wheelchair horizontally beneath lower edge  140  of baffle  128 , as shown in FIG. 9. Platform  131  is again raised, enabling person  134  to operate controls  148  of control box  147  to cause trolley  141  to translate the wheelchair to the right of right-hand end panel  129 , and to cause lift mechanism  143  to lower the wheelchair to floor level.  150 . Hooks  145  are then disengaged from the wheelchair, allowing the wheelchair and occupant to safely exit the building.  
         [0050]    As described above, methods and apparatus according to the present invention function as a barrier which inhibits heat, smoke and noxious combustion gases produced by a fire located upstream of a hallway opening or doorway in a building from diffusing into areas of the building downstream from the hallway opening, the barrier being so arranged as to enable people to quickly and safely travel through the barrier to safely exit the building. According to the invention, the barrier is not breached by a person transiting through the barrier, thus continuing to function effectively in blocking heat, smoke and noxious combustion products from traveling through the barrier with the person. The described functions are accomplished by forming an air lock in hermetically sealing contact with a hallway opening. The air lock consists of a pool of water and a vertically disposed baffle which has a lower edge that protrudes vertically downwards from a location near a hallway ceiling to a location beneath the surface of water in a pool. The baffle is disposed transversely to a longitudinal exit path through the apparatus, and sufficient clearance is provided between the lower edge of the baffle and the bottom of the pool to enable individuals to duck under the baffle edge and walk under the pool. In one embodiment, the baffle consists of a solid structure, while in another embodiment, the “baffle” consists of one or more continuously flowing curtains of water which pour downwardly into a shallow pool. In both embodiments, the apparatus is arranged to be in reasonably good hermetically sealing contact with a building hallway. However, those skilled in the art will recognize that the present invention may be advantageously utilized even if the hermetic sealing is not perfect, allowing relatively small volumes of combustion products to leak by the apparatus. The exact degree of sealing perfection is chosen according to cost/benefit trade-offs performed as part of a conventional engineering analysis. Thus, in the following claims, hermetically sealed or sealed is to be logically interpreted as substantially sealed, the exact degree of which sealing is a matter of ordinary engineering design choice.
An apparatus for inhibiting wide dispersal of heat, smoke and noxious gases from a fire in a structure such as a building occupied by people, thereby facilitating evacuation of the building through exit routes rendered relatively smoke-free by the apparatus includes a portable enclosure which has an entrance opening hermetically sealable to a doorway opening when the enclosure is moved into position adjacent to the doorway, and encloses an open-top tank which contains water, and a vertical baffle which protrudes downwardly from a roof panel of the enclosure, the baffle being disposed transversely across the enclosure with a lower edge of the baffle immersed beneath the surface of the water to thereby form a water-trap type air-lock. A method of traveling from a smoke-filled region of a building to a smoke-free region comprises stepping into water in the tank through the enclosure entrance opening, ducking the head under the lower edge of the baffle, walking on the tank bottom to the opposite side of the baffle, and exiting the tank through an exit opening in the enclosure. In one embodiment of the apparatus, a solid baffle is replaced by one or more curtains of water which flow downwardly from a manifold disposed transversely under the roof panel of the enclosure, water from the tank being recirculated to the manifold by a pump.