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This application claims the benefit of U.S. Provisional Application No. 60/162,796 filed Nov. 1, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of prefabricated concrete wall construction, and more specifically, to a safe room constructed of prefabricated concrete wall panels. 
     Every year, hundreds of people are killed by natural disasters including hurricanes, tropical storms and the like. Many of these deaths are attributable to flying debris. For example, typical wall studs are often dislodged and hurled through the air at speeds upwards of 100 miles per hour. These airborne studs become missiles which can easily travel through standard stick frame construction. As a result, people in the path of a storm generally do not have a place to hide from these objects and must rely on circumstance to avoid being struck and injured or killed. 
     An additional problem experienced during such natural disasters is the failure, and thereby the removal of roofs from places of shelter. Once the roof of the structure is removed, the people inside become at greater risk of being struck by flying and falling debris. 
     Accordingly, there is a need for a safe heaven for people to retreat to during storms which is less susceptible to the above problems. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a system for forming a safe room. A plurality of preformed concrete wall panels are interconnected to form a room perimeter. Each panel includes an extension portion and a top beam which together define a shelf. A roof panel is positioned within the room perimeter and is set upon and secured to the generally continuous shelf defined by the interconnected panels such that the roof is slightly recessed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a safe room in accordance with the present invention. 
     FIG. 2 is a perspective view of a wall panel made in accordance with the present invention. 
     FIG. 3 is a section view taken along the line  3 — 3  in FIG.  1 . 
     FIG. 4 is a partial section view taken along the line  4 — 4  in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiments will be described with reference to the drawing figures wherein like numerals represent like elements throughout. References to orientation refer to the orientation of an installed wall panel and are for clarity only. 
     FIG. 1 shows a preferred safe room  10  made in accordance with the present invention. The safe room  10  generally includes a plurality of prefabricated wall panels  30  which are connected to form a room perimeter. Each panel  30  is secured to a slab  12  or other foundation member. The room perimeter is preferably defined within and consistent with the remainder of the building structure. For example, the room  10  can be the master closet of a house or an office in a building. A roof panel  20  sits recessed within the room perimeter on a generally continuous shelf (not shown) defined by the wall panels  30 . A doorway  50  permits entrance and exit from the room  10 . 
     FIG. 2 shows a preferred planar wall panel  30  made in accordance with the present invention. The planar wall panel  30  has a solid portion which includes spaced vertical studs  32  extending between a top beam  34  and a base beam  36 . Nailing strips  38  are preferably formed integral with the vertical studs  32  and the top and base beams  34 ,  36 . Insulation panels  40  extend between the vertical studs  32 , and with studs  32 , form a solid planar inside face on the wall  30 . The outside face of the wall has a solid planer concrete surface  42 . The concrete surface  42  includes an extended portion  44  extending above the top beam  34 . The extended portion  44  and the top beam  36  define a shelf  46  for supporting the roof panel  46 . The shelf  46  includes a number of anchor receptacles  47  for securing the roof panel  46  as will be described hereinafter. Referring to FIGS. 1 and 3, a number of steel reinforcement rods  48  are positioned in the wall panel  30 . A wire lath  49  may also be included behind the insulation panels across the entire area of the wall panel  30 . The preformed wall panels  30  may also be cavity walls, wherein the insulation panels  40  are recessed from the inside face of the wall  30 , or other variations of concrete wall panels including an extended portion  44  to define a support shelf  46 . 
     Referring to FIGS. 1 and 3, adjacent wall panels  30  are butted and secured to one another using any of a number of attachment methods. As shown in FIG. 3, the panels  30  are preferably mitered, but may have flat ends which are overlapped or connected through a separate comer piece. If overlapped or connected through a comer piece, the components are preferably configured such that the shelf remains continuous about the perimeter. For example, the comer piece may be formed with a defined shelf portion. With the panels  30  secured, a generally continuous shelf  46  is defined around the perimeter of the safe room  10  with a number of anchor receptacles  47 . Although the illustrated wall panels  30  define a rectangular perimeter, the wall panels  30  can be configured to define any desired room configuration. 
     The roof panel  20  will be formed with a configuration complementary to the room perimeter configuration. Referring to FIG. 4, the roof panel  20  is preferably a solid concrete slab reinforced with steel reinforcement rods  22  and a wire lath  24 . The roof panel  20  is preferably five inches (5″) thick, but can be made to any desired thickness. The height of the wall panel extensions  44  will correspond to the slab thickness such that the roof panel  20  is flush with or slightly recessed from the top of the wall panels  30 . This makes the roof panel  20  less likely to be subjected to wind or flying debris, and therefore, less susceptible to failure. The roof panel  20  includes a plurality of bores  26  which align with the anchor receptacles  47  in the wall panels  30 . Anchor bolts  28  are positioned in the receptacles  47 , extend through the bores  26 , and are secured by a nut  29 . 
     Referring to FIGS. 1 and 3, one of the panels  30  is provided with a doorway  50 . The doorway  50  preferably includes a jam  54  from which is hung a solid steel door  52 . The door  52  preferably opens inward to avoid debris blockage and to reduce the risk of outward suction by an external wind force. The door  52  includes a lock bolt  53  which mates within a reinforced lock plate  51  in the jam  54 . Additional securing means  56 , for example a pivotable latch, may be preformed in the wall panel  30  and mate with a catch  57  on the door  52  for additional fortification. The door jam  54  includes returns  55  which extend into the concrete such that the jam  54  can be preformed in the wall panel  30  to reduce its likelihood of failure. To ensure proper operation of the door  52  in the jam  54 , the door  52  or a blank (not shown) having the same size and shape is positioned in the jam  54  during pouring of the wall panel  30 .

Summary:
A system for forming a safe room including a plurality of preformed concrete wall panels and a roof panel. Each panel includes an extension portion and a top beam which together define a shelf. The wall panels are interconnected to define a generally continuous perimeter shelf. The roof panel is positioned within the room perimeter and is set upon and secured to the generally continuous shelf.