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BACKGROUND OF THE INVENTION 
       [0001]    This invention is directed to a tornado shelter that takes the form of an especially constructed enclosure or room typically provided above-ground, in a house or other building. The enclosure is strong enough to provide a high degree of occupant protection during most tornados and other high wind events. 
         [0002]    The Federal Emergency Management Agency (FEMA) has suggested criteria for such above-ground enclosures. The criteria are discussed in the following publications: “National Performance Criteria for Tornado Shelters”, 1 st  Edition, published May 8, 1999, and “Taking Shelter from the Storm: Building a Safe Room Inside Your House”, Booklet #320, 2 nd  Edition, published August 1999. According to the criteria the enclosure should be able to withstand wind pressures developed from winds gusting for three seconds at 250 miles per hour. The enclosure must also be able to withstand the impact without perforation of a 15 lb. 2×4 wooden board traveling at a speed of 100 miles per hour horizontally along the board&#39;s longitudinal axis and vertically at 67 miles per hour. 
         [0003]    A number of inventions related to above-ground tornado shelters have been patented. These are sometimes called safe rooms. Many of these structures form the walls and ceiling of the structure with metal panels. Of particular relevance, U.S. Pat. No. 5,813,174, granted to Waller, taught a shelter that can be easily erected within an existing building from components that can be stacked and shipped in a compact manner. Waller also taught being able to build the enclosure around the installer for ease of installation in a small existing room of a building. Similarly, U.S. Pat. No. 6,415,557, granted to McCalley in 2002, and U.S. Pat. No. 6,415,558, granted to Cherry in 2002, both teach shelters that can be erected within an existing building, from the inside of the enclosure, with components that can be shipped efficiently. 
         [0004]    U.S. Pat. No. 6,415,558, granted to Cherry, is particularly concerned with using standard fasteners for connecting the panels of the structure rather than specially made parts. This made manufacturing the enclosure less expensive, and it arguably made the enclosure easier to erect by users without specialized training. Cherry was also particularly concerned with the particular manner in which the entry and exit door was connected to the other components of the enclosure and the operation of the door. On the other hand, McCalley emphasizes that the connections between his panels were designed to allow for “give” or “play” between the panels so as to dissipate the energy imparted from an impact and thereby resist penetration. 
         [0005]    U.S. Pat. No. 5,813,174, granted to Waller, teaches connecting the panels of the structure to frame components that are connected to each other and anchored to the ground, while Cherry cites as a benefit of his invention that a “separate, integrated frame structure” is not needed. However, Cherry still teaches and claims connecting his panels at the edges of the enclosure to separate elongated framing members. McCalley, similarly, teaches using separate elongated framing members to connect the panels. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an enclosure that can meet the FEMA performance criteria that is also easily assembled from relatively inexpensive components. 
         [0007]    The present invention provides an enclosure that can withstand the pressures imposed by a 250 mph ground level wind as well as the impact from a 15 lb., 2×4 wooden building stud traveling at 100 mph horizontally and 67 mph vertically. 
         [0008]    The enclosure of the present invention is primarily constructed from corrugated, symmetrical panel members of uniform shape. The panel members are preferably made from steel. The panel members are connected together to form the walls and roof of the enclosure. The enclosure is connected to a cementitious member to anchor the enclosure. The enclosure is provided with a door that completes the enclosure and allows entry and exit from the enclosure. 
         [0009]    The enclosure of the present invention is formed in a manner that an installer can easily assemble the structure with commonly available tools and with little or no specialized training. 
         [0010]    The enclosure of the present invention is formed in a manner that the user can mostly assemble the enclosure from what will become the inside of the enclosure. In this manner, the enclosure can be constructed in a small room where access to the outside of the shelter may be difficult. 
         [0011]    The enclosure of the present is also formed in a manner that the enclosure can also be partially or fully disassembled from inside the enclosure. This is particularly useful if the door to the shelter is blocked and another exit needs to be created to leave the shelter by the occupants taking refuge. 
         [0012]    The enclosure of the present invention is also formed such that the panels are connected directly to each other and separate framing members are needed only at certain edges of the enclosure. 
         [0013]    The enclosure of the present invention is formed in such a manner that it is economical to manufacture and ship. 
         [0014]    The enclosure of the present invention is also formed such that the component pieces are of a size that they can be manipulated by a single person, erecting the shelter alone. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is a perspective view of the enclosure of the present invention. 
           [0016]      FIG. 2  is a front view of the enclosure of the present invention, showing the front wall, doorway and door of the enclosure of the present invention. 
           [0017]      FIG. 3 , taken along line  3 - 3  of  FIG. 4 , is a right side view of the right end wall of the present invention. 
           [0018]      FIG. 4 , taken along line  4 - 4  of  FIG. 3 , is a top plan, sectional view of the enclosure of the present invention. 
           [0019]      FIG. 5 , taken along line  5 - 5  of  FIG. 4 , is an inside, sectional view of the front wall of the enclosure of the present invention. The base foundation is shown with anchors embedded in the base foundation. The door is not shown. 
           [0020]      FIG. 6 , taken along line  6 - 6  of  FIG. 4 , is a view of the back wall of the enclosure of the present invention. 
           [0021]      FIG. 7 , taken along line  7 - 7  of  FIG. 4 , is an inside, sectional view of the back wall of the enclosure of the present invention. 
           [0022]      FIG. 8 , taken along line  8 - 8  of  FIG. 4 , is an inside, sectional view of the right end wall of the enclosure of the present invention. The view of the left end wall is similar. 
           [0023]      FIG. 9  is a close-up, top plan view of the connection of the door frame to a panel in the front wall of the enclosure of the present invention. 
           [0024]      FIG. 10  is a close-up, top plan view of the connection between two panels in the right end wall of the enclosure of the present invention. 
           [0025]      FIG. 11  is a close-up, top plan view of the connection between the panels at the side edge between the front wall and the right end wall of the enclosure of the present invention. 
           [0026]      FIG. 12  is a close up, top plan view of the connection between the panels at the side edge between the back wall and right end wall of the enclosure of the present invention. 
           [0027]      FIG. 13  is a perspective view, showing portions of the roof, the front wall and right end wall of the enclosure of the present invention. 
           [0028]      FIG. 14  is a perspective view, showing portions of the roof and the front wall of the present invention. 
           [0029]      FIG. 15  is an end view of one of the bottom caps of the front wall of the enclosure of the present invention. 
           [0030]      FIG. 16  is a front view of one of the bottom caps of the front wall of the enclosure of the present invention. 
           [0031]      FIG. 17  is a top view of one of the bottom caps of the front wall of the enclosure of the present invention. 
           [0032]      FIG. 18  is an end view of the top caps of the front and back walls of the enclosure of the present invention. 
           [0033]      FIG. 19  is a front view of the top caps of the front and back walls of the enclosure of the present invention. 
           [0034]      FIG. 20  is a top view of the top caps of the front and back walls of the enclosure of the present invention. 
           [0035]      FIG. 21  is an end view of the bottom cap of the back walls of the enclosure of the present invention. 
           [0036]      FIG. 22  is a front view of the bottom cap of the back wall of the enclosure of the present invention. 
           [0037]      FIG. 23  is a top view of the bottom cap of the front wall of the enclosure of the present invention. 
           [0038]      FIG. 24  is an end view of the top caps of the end walls of the enclosure of the present invention. 
           [0039]      FIG. 25  is a front view of the top caps of the end walls of the enclosure of the present invention. 
           [0040]      FIG. 26  is a top view of the top caps of the end walls of the enclosure of the present invention. 
           [0041]      FIG. 27  is an end view of the bottom caps of the end walls of the enclosure of the present invention. 
           [0042]      FIG. 28  is a front view of the bottom caps of the end walls of the enclosure of the present invention. 
           [0043]      FIG. 29  is a top view of the bottom caps of the end walls of the enclosure of the present invention. 
           [0044]      FIG. 30  is an end view of one of the bottom caps of the front wall of the enclosure. 
           [0045]      FIG. 31  is a front view of one of the bottom caps of the front wall of the enclosure. 
           [0046]      FIG. 32  is a top view of one of the bottom caps of the front wall of the enclosure. 
           [0047]      FIG. 33  is an end view of the top piece of the door frame in the front wall of the enclosure. 
           [0048]      FIG. 34  is a front view of the top piece of the door frame in the front wall of the enclosure. 
           [0049]      FIG. 35  is a top view of the top piece of the door frame in the front wall of the enclosure. 
           [0050]      FIG. 36  is a top view of a middle panel of the enclosure of the present invention. The bottom view is similar. The middle panels are bordered on either side by other panels. The middle panels are also used in both the roof and walls of the structure or enclosure. 
           [0051]      FIG. 37  is a right side view of the middle panel of the enclosure. 
           [0052]      FIG. 38  is a front view of the middle panel of the enclosure. 
           [0053]      FIG. 39  is a left side view of the middle panel of the enclosure. 
           [0054]      FIG. 40  is a top view of a door header panel of the enclosure of the present invention. The bottom view is similar. 
           [0055]      FIG. 41  is a right side view of the door header panel of the enclosure. 
           [0056]      FIG. 42  is a front view of the door header panel of the enclosure. 
           [0057]      FIG. 43  is a left side view of the door header panel of the enclosure. 
           [0058]      FIG. 44  is a top view of a first corner wall panel of the enclosure of the present invention. The bottom view is similar. 
           [0059]      FIG. 45  is a right side view of the first corner wall panel of the enclosure. 
           [0060]      FIG. 46  is a front view of the first corner wall panel of the enclosure. 
           [0061]      FIG. 47  is a left side view of the first corner wall panel of the enclosure. 
           [0062]      FIG. 48  is a top view of a roof end panel of the enclosure of the present invention. The bottom view is similar. 
           [0063]      FIG. 49  is a right side view of the roof end panel of the enclosure. 
           [0064]      FIG. 50  is a front view of the roof end panel of the enclosure. 
           [0065]      FIG. 51  is a left side view of the roof end panel of the enclosure. 
           [0066]      FIG. 52  is a top view of a first door frame panel of the enclosure of the present invention. The bottom view is similar. 
           [0067]      FIG. 53  is a right side view of the first door frame panel of the enclosure. 
           [0068]      FIG. 54  is a front view of the first door frame panel of the enclosure. 
           [0069]      FIG. 55  is a left side view of the first door frame panel of the enclosure. 
           [0070]      FIG. 56  is a top view of an alternate door frame panel of the enclosure of the present invention. The bottom view is similar. 
           [0071]      FIG. 57  is a right side view of the alternate door frame panel of the enclosure. 
           [0072]      FIG. 58  is a front view of the alternate door frame panel of the enclosure. 
           [0073]      FIG. 59  is a left side view of the alternate door frame panel of the enclosure. 
           [0074]      FIG. 60  is a top view of an alternate corner wall panel of the enclosure of the present invention. The bottom view is similar. 
           [0075]      FIG. 61  is a right side view of the alternate corner wall panel of the enclosure. 
           [0076]      FIG. 62  is a front view of the alternate corner wall panel of the enclosure. 
           [0077]      FIG. 63  is a left side view of the alternate corner wall panel of the enclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0078]    As shown in  FIGS. 1 and 2 , the present invention is a protective enclosure  1 . The enclosure has a front wall  2  having a left edge  3  and a right edge  4 . A left end wall  5  is attached to the front wall  2 . The left end wall  5  has a front edge  6  and a back edge  7 . The left end wall  5  is attached to the front wall  2  at a left, front edge  8  of the enclosure  1 . A right end wall  9  is attached to the right edge  4  of the front wall  2 . The right end wall  9  has a front edge  10  and a back edge  11 . The right end wall  9  attaches to the front wall  2  at a right, front edge  12  of the enclosure  1 . The enclosure has a back wall  13  having a left edge  14  and a right edge  15 . The back wall  13  is attached to the left end wall  5  at a left, back edge  16  of the enclosure  1 , and the back wall  13  is attached to the right end wall  9  at a right, back edge  17  of the enclosure  1 . The enclosure  1  also has a roof  18  having front, back and left and right boundary edges  19 ,  20 ,  21  and  22 . The roof  18  is attached to the front wall  2  at the front boundary edge  19 . The roof  18  is attached to the back wall  13  at the back boundary edge  20 . The roof is attached to the left end wall  5  at the left boundary edge  21  and to the right end wall  9  at the right boundary edge  22 . The enclosure  1  is supported by and is attached to a base  23 . Preferably, the foundation base  23  is made from cement. Each of the walls  2 ,  5 ,  9  and  13  is attached to the base. The enclosure  1  is also formed with an opening large enough for a human to enter and exit the enclosure  1 . 
         [0079]    As shown in  FIG. 1 , the front, back, and left end and right end walls  2 ,  13 ,  5  and  9  are made up of a plurality of panels  24 . Each panel has a top end  25 , a bottom end  26 , and left and right side edges  27  and  28 . The top end  25 , bottom end  26  and left and right side edges  27  and  28  of each panel  24  define a diaphragm  29 . The panels  24  have side flanges  30  and  31  attached to the left and right side edges  27  and  28  of the panels  24 . As shown in  FIGS. 5, 7 and 8 , each panel  24  is connected to at least one adjacent panel  24  by at least one fastener  32  received by the panel  24  and the adjacent panel  24  through adjacent side flanges  30  and  31 . As shown in  FIGS. 4, 36 and 38 , each panel is formed with a corrugation  33  in the diaphragm  29  of each panel  24 . 
         [0080]    As shown in  FIGS. 1 and 2 , the front and back walls are preferably longer than the end walls, and preferably the front wall is formed with a door way  34 , having a door frame  35  and a door  36 . 
         [0081]    The panels  24  are preferably made from cold-formed steel and are preferably bolted together. The panels  24  are preferably all of the same dimensions, except for the shortened panels disposed over the doorway  34  which are of a different length (see  FIG. 2  and  FIGS. 40-43 ), and except for the arrangement of the openings  37  for connecting the panels  24  to each other and to the framing members  38 . As shown in  FIGS. 36-63 , the panels  24  are preferably elongate members having a top end  25 , a bottom end  26  and left and right sides edge  27  and  28 , with the side edges  27  and  28  being longer than the top and bottom ends  24  and  26 . The top and bottom ends  25  and  26  are preferably parallel with each other, as are the left and right side edges  27  and  28 , such that the panel  24  is rectangular. The elongated side edges  27  and  28  define the longitudinal dimension of the panel with a longitudinal axis  39  running from the top end  25  to the bottom end  26 . The panels  24  are preferably symmetrical in their overall shape along the longitudinal axis  39 . The panels  24  also have a lateral axis  40  that extends from the left side edge  28  to the right side edge  28 , parallel to the top and bottom ends  25  and  26 . The panels  24  are preferably symmetrical in their overall shape along the lateral axis  40 . 
         [0082]    As shown in  FIGS. 1, 5, 7, 8 , within each wall  2 ,  5 ,  9  and  13  and the roof  18 , the side edges  27  and  28  of the panels  24  are connected to each other. In the preferred embodiment, at the edges  3 ,  4 ,  6 ,  7 ,  10 ,  11 ,  14 , and  15  of the walls  2 ,  5 ,  9  and  13 , where the front and back walls  2  and  13  meet the end walls  5  and  9 , the panels  24  at the edges  3 ,  4 ,  6 ,  7 ,  10 ,  11 ,  14 , and  15  of the front and back walls  2  and  13  and the end walls  5  and  9  connect to each other. See  FIGS. 11 and 12 . In the preferred embodiment, in the walls  2 ,  5 ,  9  and  13 , and the roof  18 , the panels  24  attach at their top and bottom ends  25  and  25  to framing members  38 . The connections between the panels  24 , and between the panels  24  and the framing members  38 , are preferably made with fasteners  32 . The preferred fasteners  32  are bolts and nuts with washers. 
         [0083]    As best seen in  FIGS. 4 and 36 through 39 , preferably, the panels  24  have a diaphragm  29  that is corrugated, such that the diaphragm  29  has a non-planar cross-section. The corrugation  33  preferably extends the entire height of the panel  24  along its longitudinal axis  39  from its top end  25  to its bottom end  26 , but the corrugation  33  does not need to extend the entire height of the panel  24 , nor does it need to reach either of the ends  25  and  26 . 
         [0084]    The corrugation  33  may be any ridge, groove, protrusion or plurality of protrusions, angle or angles formed in the central diaphragm  29  of the panel  24 . Preferably, the corrugation  33  extends in the height direction at least partially between the top end  25  and the bottom end  26 . 
         [0085]    In the preferred embodiment, the panel  24  is formed with a single corrugation  33  that extends from the top end  25  to the bottom end  26 . The preferred corrugation  33  creates front and back portions of the diaphragm  29  that lie in different planes. The preferred diaphragm  29  with its corrugation  33  has first and second front planar sections  41  and  42  near the side edges  27  and  28  of the diaphragm  24 . The first front planar section  41  is adjacent the left side edge  27  of the panel  24 , and the second front planar section  42  is adjacent the right side edge  28  of the panel  24 . First and second planar angle sections  43  and  44  extend from the first and second front planar sections  41  and  42 , respectively, to a rear planar section  45 . The first and second planar angle sections  43  and  44  and the rear planar section  45  make up the corrugation  33  in the preferred embodiment. In the preferred embodiment, all of the sections of the diaphragm  29  run vertically and extend the entire height of the panel  24 . The corrugation  33  provides increased ductility to the diaphragm  29  of the panel  24 . 
         [0086]    As shown in  FIG. 36 , in the preferred embodiment, the front planar sections  41  and  42  of the diaphragm  29  are coplanar and define the front extent of the panel  24  and the rear planar section  45  is also planar and substantially defines the rear extent of the panel  24  such that the corrugation  33  substantially traverses the entire depth of the panel  24 . 
         [0087]    Preferably, at the side edges  27  and  28  of the panel  24  there are provided side flanges  30  and  31  that extend substantially the depth of the panel  24 . The side flanges  30  and  31  preferably extend the longitudinal height of the panel  24 . Preferably, the side flanges  30  and  31  are planar members. Also in the preferred embodiment, the side flanges  30  and  31  lack returns or any additional members that would make them non-planar. The fact that the side flanges  30  and  31  are planar without additional returns allows the panels  24  to overlap at the intersections of the walls  8 ,  12 ,  16  and  17 . The shapes of the front planar sections  41  and  42  and the side flanges  30  and  31  are preferably symmetrical along the longitudinal axis  39 . 
         [0088]    As an example of the overlap, at the left, front edge of the enclosure  8 , the panel  24  at the left edge  3  of the front wall  2  is attached to the panel  24  at the front edge  6  of the left end wall  6 , with the left side flange  30  of the panel at the left edge  3  of the front wall  2  registering with the second front planar section  42  of the panel  24  at the front edge  6  of the left end wall  5 .  FIG. 11  which is a sectional, close-up of the right, front edge  12  of the enclosure  1  taken from  FIG. 4  is another example of this overlap. The panel  24  at the right edge  4  of the front wall  2  is attached to the panel  24  at the front edge  10  of the right end wall  9 , with the right side flange  31  of the panel  24  at the right edge  4  of the front wall  2  registering with the first front planar section  41  of the panel  24  at the front edge  10  of the right end wall  9 , and with the second front planar section  42  of the panel  24  at the right edge  4  of the front wall  2  registering with the left side flange  30  of the panel  24  at the front edge  6  of the left end wall  5 . The interface between panels at the left and right back edges  16  and  17  of the enclosure  1  is the same. 
         [0089]    As shown in  FIG. 1 , in the preferred embodiment, in the walls  2 ,  5 ,  9  and  13  of the enclosure  1 , the front planar sections  41  and  42  are disposed outwardly from the inside of the enclosure  1  and the rear planar section  45  is disposed inwardly toward the inside of the enclosure  1 , such that the corrugation&#39;s concave face faces outwardly from the inside of the enclosure  1  and the convex face of the corrugation  33  faces into the enclosure  1 . The side flanges  30  and  31  extend into the enclosure  1 . 
         [0090]    As shown in  FIG. 8 , in the preferred embodiment, in the roof  18  of the enclosure  1 , the front planar sections  41  and  42  are disposed inwardly toward the inside of the enclosure  1  and the rear planar section  45  is disposed outwardly from the inside of the enclosure, such that the corrugation&#39;s concave face faces inwardly into the enclosure and the convex face of the corrugation  33  faces away from the inside of the enclosure  1 . The side flanges  30  and  31  of the roof panels  24  extend outwardly from the interior of the enclosure  1 . 
         [0091]    As shown in  FIG. 5 , preferably, a plurality of longitudinally spaced fasteners  32  extend through the side flanges  30  and  31  of in-line, adjacent panels  24  to connect them. In a similar fashion, fasteners  32  are used to connect adjacent panels at the edges of the enclosure  8 ,  12 ,  16  and  17 . 
         [0092]    As shown in  FIGS. 38, 42, 46, 50, 54, 58, and 63 , in the preferred embodiment, the front planar sections  41  and  42  of the diaphragm  29  will also have fastener openings  32  for connecting the panels  24  to each other and to the framing members  38 . Depending on where the panel member  24  is to be positioned in the enclosure, it will have a particular arrangement of fastener openings  37  in the front planar sections  41  and  42  and the side flanges  30  and  31 . In the preferred embodiment, all of the panels  24  are formed with openings in the front planar sections  41  and  42  at the four corners of the panel  24 , for connecting each panel  24  at its top and bottom at two points. The panels  24  that are disposed at the edges  8 ,  12 ,  16  and  17  of the enclosure  1  are then formed with additional openings  37  along the side of the panel  24  that will be disposed at the enclosure edge  8 ,  12 ,  16  or  17 . 
         [0093]    As shown in  FIGS. 1, 2, 3 and 6 , preferably, each wall  2 ,  5 ,  9  and  13  of the enclosure  1  has framing members  38  that extend the length of each wall. The framing members  38  connect the upper portions of the walls to the roof  18  by means of fasteners  32  that connect the upper portions of the panels to the framing member  38  and by fasteners  32  that connect the framing member to the panels  24  of the roof  18  having boundary portions at the side edges  19 ,  20 ,  21  and  22  of the roof  18 . 
         [0094]    As shown in  FIGS. 21-26 , the framing members  38  are preferably two elongated members joined at a 90 degree angle, creating a horizontally disposed flange  46  and a vertically disposed member  47  when installed. In the preferred embodiment, the first and second framing members  38  at the tops of the end walls  5  and  9  are T-shaped top caps  48 , and for the front and back walls are L-shaped angle members  49 . In the preferred embodiment, there are four top framing members  38  in total. 
         [0095]    As shown in  FIGS. 25 and 26 , in the preferred embodiment, the vertical walls  47  of the T-shaped end wall top caps  48  are formed with regularly spaced notches  50 , creating projections  51 . The material of the notches is bent orthogonally to create the horizontal flange  46 . The portions of the horizontal flange  46  are not continuous. The projections  51  of the vertical flange  47  between the notches  50  cover the open ends  52  of roof panels  24  where the corrugation  33  of the roof panels  24  would create an opening. As shown, in the preferred embodiment, the front planar sections  41  and  42  of the roof panels  24  are aligned and connect to the horizontal flange  46  of the end top caps  48 , with the corrugation  33  extending above the plane created by the front panel sections  41  and  42 . The projections  51  of the top caps  48  cover the protruding corrugation  33  of the roof panels  24 . The horizontal flanges  46  of the L-shaped angle members  49  connect to front planar sections  41  or  42  of roof panels  24  by means of fasteners  32 , and the vertical wall  47  of the L-shaped angle members  49  connects to the front planar sections  41  and  42  of wall panels  24 . 
         [0096]    As shown in  FIGS. 1, 2, 3 and 4 , similarly, each wall  2 ,  5 ,  9  and  13  of the enclosure  1  has bottom framing members  38  that connect the bases of the panels  24  to the base  23  of the enclosure  1 . In the preferred embodiment, the back wall  13 , and the end walls  5  and  9  have bottom framing members  38  that extend the length of those walls. In the preferred embodiment, where a doorway  34  is formed in the front wall  2 , the front wall  2  has two bottom framing members  38  that are disposed underneath the panels  24  that are anchored to the base  23 , with no bottom framing member underneath the doorway  34 . In the preferred embodiment, there are five bottom framing members in total. 
         [0097]    Preferably, the framing members  38  are formed with openings  53  at predetermined locations for receiving the fasteners that will connect the framing members  38  to the panels  24  and the fasteners  54  that will connect the framing members  38  to the base foundation  23  of the enclosure  1 . 
         [0098]    As shown in  FIGS. 4, 11 and 12 , in the preferred embodiment, the bottom framing members are formed such that the horizontal flanges  46  resting on the base  23  of the enclosure  1  do not overlap each other where they meet at the corners of the enclosure  1 . In the preferred embodiment, the ends of the horizontal flanges  46  of the framing members  38  for the end walls  5  and  9  do not extend as far as the vertical flanges  47 , so that the horizontal flange  46  of the framing member  38  of the end wall  5  or  9  does not overlap the corresponding horizontal flange  46  of the framing member  38  of the framing members  38  of the front and back walls  2  and  13 . 
         [0099]    As shown in  FIGS. 2 and 3 and 4 and 11 , in the preferred embodiment, the vertical member  47  of the bottom framing members  38  is located on the outside of the wall panels  24 . Similarly, as shown in  FIG. 13 , the vertical flange of the top framing member  38  is located on the outside of the wall panels  24 . As is also shown in  FIG. 13 , the horizontal flange  46  of the top framing members  38  is disposed underneath the roof panels  24 . 
         [0100]    As shown in  FIGS. 1, 2 and 33-35 , a lintel  55  is also provided for above the doorway  34  to anchor the bottom portions of the shortened panels  24  that are provided above the doorway  34 . 
         [0101]    As shown in  FIG. 4 , each bottom framing member has an anchor  54  in its horizontal flange  46  near the bottom corners of each panel  24 . The preferred anchors  54  are thread-in anchors for being set in a predrilled bore in the foundation base  23 . Preferably, a high strength washer  56  is disposed between the head  57  of the anchor  54  and the horizontal flange  46  of the bottom cap or framing member  38 . 
         [0102]    As shown in  FIGS. 5, 7, 8 and 10 , in the preferred embodiment, within the walls  2 ,  5 ,  9  and  13 , where aligned panels  24  connect to each other, no additional members are provided and the side flanges  30  and  31  of adjacent panels  24  register with each other, and are connected directly to each other. In the preferred embodiment, the openings  37  in the interfacing side flanges  30  and  31  of adjacent panels are aligned with each other and fasteners  32  disposed in the aligned openings  37  connect the adjacent panels  24 . 
         [0103]    As shown in  FIG. 11 , in the preferred embodiment, at the edges  8 ,  12 ,  16  and  17  of the enclosure  1 , where the walls  2 ,  5 ,  9  and  13  connect to each other, no framing members are provided. The panels  24  at each edge  3  and  4  of the front wall  2  connects directly to the panel  24  at the edge  6  or  10  of the end wall  5  or  9  adjacent to it, and similarly, the panels  24  at each edge  14  and  15  of the back wall  13  connect directly to the panel  24  at the edge  7  or  11  of the end wall  3  or  9  adjacent to it.  FIG. 11  is a close up view, taken from  FIG. 4 , of the connection between the front wall  2  and the right end wall  9 . The edge panel  24  of the front wall  2  is received by the edge panel  24  of the right end wall  9 . In particular, the second or right front planar section  42  of the panel  24  of the front wall  2  interfaces with the left side flange  30  of the panel  24  of the right end wall  9 . The right or second front section  42  of the panel  24  of the front wall  2  is connected to the left side flange  30  of the panel  24  of the right front wall  9  by fasteners  32 . Similarly, the right side flange  31  of the panel  24  of the front wall  2  interfaces with the left or first front planar section  41  of the panel  24  of the right end wall  9  and is connected to it by fasteners  32 . In the preferred embodiment of the enclosure  1 , the connections between the walls at the three other edges  11 ,  16  and  17  of the enclosure are similar with the panel  24  of the front or back wall  2  or  9  received by the panel  24  of the end wall  5  or  9 .  FIG. 12  is a close up view, taken from  FIG. 4 , of the right edge connection between the back wall  13  and the right end wall  9 . 
         [0104]    As shown in  FIG. 9 , the door frame  35  is connected to panels  24  in the front wall  2  with screws  58  driven through the side flanges  30  and  31  of the panels  24 . As shown in  FIG. 35 , the lintel  55  for the door way  34  is formed with smaller openings in the horizontal flange  46  to indicate that threaded screw fasteners  58  are used to connect the top of the door frame  35  to the lintel  55 . 
         [0105]    An enclosure  1  formed according to the present invention can be assembled in the following manner. The bottom caps or framing members  38  are rigidly connected to the base foundation  23  using appropriate anchors  54 . Then the panels  24  of the walls  2 ,  5 ,  9 , and  13  are connected to the bottom caps  38 , and the top caps or framing member  38  are connected to the panels  24  of the walls  2 ,  5 ,  9 , and  13 . The roof  18  is installed on the last. 
         [0106]    Preferably, the panels  24  are formed from 10 gauge, grade 33, G 90 cold-formed sheet steel. The wall panels are preferably 96 inches tall, 12 inches wide and three inches deep. The front planar sections  41  and  42  of the panels are three inches wide. The corrugation is six inches wide. In the preferred embodiment, the planar angled sections  43  and  44  of the corrugation  33  are set at 90 degrees to each other. The planar horizontal flanges  46  and vertical walls  47  of the framing members  38  are preferably three inches wide, except the vertical members of the top caps  48  of the end walls  5  and  9  which are six inches tall. The presence of the corrugation  33  allows the panels to be made from light gauge steel and still be able to resist penetration by flying debris, and in particular to meet the criteria set for a 2×4 projectile. 
         [0107]    Preferred fasteners  32  for connecting the panels  24  and the framing members  38  to each other are bolts with nuts. Washers  59  help the bolt from being pulled through the openings in the framing members  38  and the panels  24 .

Summary:
A protective enclosure that is primarily constructed from corrugated, symmetrical panel members of uniform shape. The panel members are made from steel. The panel members are connected together to form the walls and roof of the enclosure. The enclosure is connected to a cementitious member to anchor the enclosure. The enclosure is provided with a door that completes the enclosure and allows entry and exit from the enclosure.