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TECHNICAL FIELD 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/136,902 that was filed on Mar. 23, 2015, for an invention titled CLASSROOM RETROFIT BARRIER. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates generally to ballistic barriers. More specifically, the present invention relates to a system and method for retrofitting an entryway to a classroom or the like. 
       BACKGROUND 
       [0003]    In today&#39;s society there has arisen a need to provide protection for students against active shooters (gunmen) attacking defenseless victims on school campuses. There are many approaches being considered for such protection including but not limited to; more campus police, arming teachers, ballistic backpacks, etc. 
         [0004]    One approach is disclosed in U.S. Pat. No. 9,145,729 entitled Classroom Ballistic Barriers, issued Sep. 29, 2015 to DAW Technologies, LLC, where the barrier system comprised a ballistic panel nested slidably in upper and lower channels to slide across a doorway and lock into position. The sliding ballistic panel operates independent of the classroom door and manually must be slid across the doorway opening. Similarly, in U.S. Pat. No. 9,234,724, also entitled Classroom Ballistic Barriers and issued Jan. 12, 2016 to DAW Technologies, LLC, a barrier system comprised of one or more ballistic panels slide across door or window openings to provide ballistic shielding against attacks through such openings. Again, the sliding ballistic panels operate independent of the classroom door or window and manually must be slid across the opening. Such systems and other efforts to shield students from active shooters have their drawbacks. Many such systems are made of expensive materials and can be time-consuming and expensive to install. Also, they may compromise the ability to make an emergency exit from the classroom. 
         [0005]    What is needed is a ballistic shielding solution that is effective, requires minimal effort to deploy, and is cost-effective for schools or office buildings to purchase and install. The embodiments of the present disclosure may cost-effectively turn almost any classroom into a “safe room”. Creating “safe rooms” on campuses drastically reduces or eliminates the “opportunity” and permits trained professionals adequate time to respond to the threat. The retrofit barrier of the present disclosure has a non-alarming appearance to students; it is simple to operate; it is be bullet resistant; and it prevents breaching for some predetermined length of time, thus allowing time for local police/SWAT to respond. 
       SUMMARY OF THE INVENTION 
       [0006]    The classroom ballistic barriers of the present disclosure provide barrier-of-entry shielding that may be retrofit to the existing classroom door by the school&#39;s own maintenance staff and will not inhibit emergency exits through the door. The system and method of the present disclosure combines a minimally-thick ballistic skin with a solid-core wood as is typically used as a classroom door to create a shield equivalent to a N.I.J. Level IIIA ballistic panel. Hence, it is possible to retrofit a relatively thin ballistic skin onto an existing door to provide protection against multiple 0.44 magnum and 9 mm handgun blasts, as well as multiple 12-gauge shot gun blasts. The ballistic skin comprises ballistic fiberglass reinforced plastic (FRP) material. N.I.J. Level IIIA protection must stop five rounds from a 0.44 magnum or five rounds from a 9 mm handgun within a 12″×12″ square shot 16 feet 4 inches away, with no penetrations. Normally, to achieve N.I.J. Level IIIA protection with this type of material, it would require a minimum of a ½″ thickness. Because this material weighs approximately 6 pounds per square foot, providing that thickness would add too much weight to the door, would make it difficult for a single maintenance person to install, and would add unnecessary cost. However, by applying the ballistic skin of a ¼″ thickness to an existing door, the weight of the ballistic shielding is cut in half making it capable of installation by a single maintenance person, and the cost of the shielding is significantly reduced. Moreover, by using lightweight (thinner) ballistic material, the added weight will not fatigue the existing door, nor will the shielding protection provided be exorbitantly expensive for schools. 
         [0007]    In an exemplary embodiment, mechanical fasteners are used to ensure that the door will perform consistently against ballistic threats versus adhesive or double-sided adhesive tape. The adhesives suitable for securing the ballistic skin to a typical classroom door can vary greatly depending upon the substrate or substrate preparation. Hence, to use adhesives to secure the ballistic skin to the door can add unnecessary complexity to a retrofit installation. By using mechanical fasteners, a residing maintenance worker for each school and/or office building is likely skilled sufficiently to install the ballistic skin to the door. Furthermore because it is imperative that the ballistic performance not be compromised because of inattention to detail, retrofit installations using mechanical fasteners is preferred. In short, the mechanical fasteners make for a fool-proof installation. 
         [0008]    The ballistic skin is custom fit to each door with an array of holes predrilled into the skin enabling the installer to use the skin as a drill template during installation. The array of holes are spaced from the outer boundary edges of the ballistic skin and the number and position of the holes assure that the ballistic performance is not compromised and the ballistic skin remains secured to the door during a gunfire attack. To permit the existing door to properly close without the need for any modification of door or jambs, the ballistic skin is held spaced from the edges of the door so that the edges of the ballistic skin abuts the periphery of the jamb. Top and bottom ballistic skin clamps are provided to ensure a tight connection between the door and the ballistic skin without the need of any adhesives. Ballistic fiberglass reinforced plastic (FRP) is difficult to bond to since it has a relatively “greasy” surface, so using mechanical fasteners and the top and bottom skin clamps solve any bonding issues. The mechanical fasteners are tamper resistant through-bolts that are secured from classroom, non-threat side of the door. In some embodiments, the use of sex-bolts ensures that the fastener cannot be compromised from the hall, threat side of the door. 
         [0009]    It should be understood, however, that the systems and methods of the present disclosure may also be used in new construction and in total door replacement situations. In these types of installations, it may be preferable to use an adhesive attachment of the ballistic skin to the door. Those skilled in the art will understand what types of adhesives would be suitable. Also, in the instance of total door replacement, the residing maintenance worker is likely capable of installing the replacement door, and in new construction, a qualified construction worker will handle the construction and hanging of the ballistic door. 
         [0010]    If the door has a window, the window is replaced with a ballistic glazing and frame so that the ballistic panel overlaps at the joint between the door and the ballistic glazing. The ballistic glazing is fixed in place by the ballistic frame, comprising both an interior frame portion and an exterior frame portion, to ensure that the ballistic protection extends over the entire door area. 
         [0011]    To shield the latch area of the door, a latch guard (hallway, threat side) and a latch support (classroom, non-threat side) are incorporated to protect the door against forced entry. With minimal alteration, the ballistic skin, a modified latch guard, and modified latch support may be fit onto a door that has panic hardware or fit panic hardware onto a door that has been retrofit with this ballistic skin. Those skilled in the art, armed with this disclosure would be able to make the minimal alterations to accommodate panic hardware. 
         [0012]    The classroom ballistic barrier can be a sliding panel or hinged panel depending upon the configuration of the door opening or window opening to be blocked. The barrier must not inhibit, impede, or change the egress through the door. It must be simple to operate, it must be bullet resistant, and lastly it must be impenetrable for some predetermined length of time. 
         [0013]    Because the barrier is located inside the door opening (for someone looking down a long hallway) it will not be immediately obvious which rooms are the “safe rooms.” 
         [0014]    The ballistic barrier of the present disclosure is always in position whenever the door is closed and locked (in a normal locking fashion). The ballistic barrier in no way inhibits, impedes, or changes the safe egress through the door. 
         [0015]    To accommodate various types of classroom or office building doors, the ballistic skins can be made to suit each type of these typical doors. Also, the classroom/office side of the ballistic skin may be made in various finishes to blend into the surroundings. In some embodiments, the ballistic skin may be covered with cork or a white board material. Hence, the classroom barrier can be disguised as a simple bulletin board for everyday use so as not to unduly alarm young students or inform would be assailants of its existence. 
         [0016]    It has been considered that many different materials could be utilized in place of the ballistic fiberglass depending upon the likely threat, the desired complexity of the install, and response time of local law enforcement. Such materials are known to those of skill in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The manner in which the above-recited and other features and advantages of the disclosed exemplary embodiments are obtained will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only exemplary embodiments and are, therefore, not to be considered limiting of the scope of this disclosure, the exemplary embodiments of this disclosure will be described with additional specificity and detail through use of the accompanying drawings in which: 
           [0018]      FIG. 1  is an elevation view from inside a room showing an exemplary ballistic barrier panel as applied to the inside of a classroom door. 
           [0019]      FIG. 2  is an elevation view of the opposite side of the classroom door depicted in  FIG. 1  showing the side outside of the classroom as in a hallway or the like. 
           [0020]      FIG. 3  is a side elevation view of the classroom door depicted in  FIG. 1  showing the door latch and protections at the door latch. 
           [0021]      FIG. 4  is an elevation view of the classroom door depicted in  FIG. 1  showing various section view references. 
           [0022]      FIG. 5  is a perspective view of a portion of a door showing the outside door knob and latch guard used to inhibit tampering and/or opening the door when locked. 
           [0023]      FIG. 6  is a perspective view of a portion of a door showing the inside door knob and latch support used to shield the door knob ballistically and to inhibit tampering and/or opening the door when locked. 
           [0024]      FIG. 7  is horizontal section view of the classroom door of  FIG. 4  viewed along line D-D above the door knob. 
           [0025]      FIG. 8  is a horizontal section view of the classroom door of  FIG. 4  viewed along line A-A showing the section of the interface of the door to an inset ballistic window. 
           [0026]      FIG. 9  is a vertical section view of the classroom door of  FIG. 4  viewed along line B-B showing the top ballistic skin clamp securing the ballistic skin. 
           [0027]      FIG. 10  is a vertical section view of the classroom door of  FIG. 4  viewed along line C-C showing the bottom ballistic skin clamp securing the ballistic skin. 
           [0028]      FIG. 11  is a perspective view of an open doorway showing another exemplary embodiment of a shielded classroom door with panic hardware. 
           [0029]      FIG. 12  is a perspective view of an open doorway showing yet another exemplary embodiment of a shielded classroom door with alternative panic hardware. 
           [0000]    
         
           
                 
               
                 
                 
                 
               
             
                 
                     
                 
                 
                   REFERENCE NUMBERS 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                     
                   ballistic door 10 
                   existing door 11 
                 
                 
                     
                   door latch 12 
                   threat side 13 
                 
                 
                     
                   door knob 14 
                   non-threat side 15 
                 
                 
                     
                   inset window 16 
                   ballistic assembly 17 
                 
                 
                     
                   ballistic skin 18 
                   top ballistic skin clamp 20 
                 
                 
                     
                   bottom ballistic skin clamp 22 
                   ballistic glazing or window 24 
                 
                 
                     
                   ballistic frame 26 
                   interior frame portion 28 
                 
                 
                     
                   exterior frame portion 30 
                   mechanical fasteners 32 
                 
                 
                     
                   peripheral edges 34 
                   outer boundary edges 36 
                 
                 
                     
                   joint 38 
                   latch guard 40 
                 
                 
                     
                   latch support 42 
                   panic hardware 44 
                 
                 
                     
                   array of holes 46 
                   plurality of holes 48 
                 
                 
                     
                   through-holes 50 
                   set of holes 51 
                 
                 
                     
                   window void 52 
                   aligning holes 54 
                 
                 
                     
                   latch void 56 
                 
                 
                     
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Exemplary embodiments of the present disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of the exemplary embodiments of the present disclosure, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of exemplary embodiments of the apparatus, system, and methods of the present disclosure, as represented in  FIGS. 1 through 12 , is not intended to limit the scope of the invention, as claimed, but is merely representative of exemplary embodiments. 
         [0031]    The phrases “connected to,” “coupled to” and “in communication with” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be coupled to each other even though they are not in direct contact with each other. The term “abutting” refers to items that are in direct physical contact with each other, although the items may not necessarily be attached together. 
         [0032]    The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
         [0033]    The classroom ballistic barriers of the present disclosure are ingress barriers comprising at least one ballistic panel specifically designed to block entry through a locked classroom door or any other door where warding off an armed assailant is desirable. 
         [0034]    Turning to  FIGS. 1-4 , elevation views of an exemplary ballistic shield for a classroom door or any other door where such shielding would be desired are shown.  FIG. 1  shows a ballistic door, generally designated  10 , as viewed from inside a room. The ballistic door  10  comprises and existing door  11  having a door latch  12  with a door knob  14  and an inset window  16 . The existing door  11  also having a threat side  13  and a non-threat side  15 . The exemplary embodiment of the ballistic door  10  also has a ballistic assembly  17  that may comprise a ballistic skin  18 , a top ballistic skin clamp  20 , a bottom ballistic skin clamp  22 , a ballistic window  24 , and a ballistic frame  26 , comprising both an interior frame portion  28  and an exterior frame portion  30  (not shown in  FIG. 1 , see  FIG. 2 ) that are secured to the existing door  11 . The ballistic skin  18 , the top ballistic skin clamp  20  and the bottom ballistic skin clamp are secured to the non-threat side  15  of the existing door  11 , while in cases where the existing door  11  has an inset window  16 , the ballistic frame  26  captures the ballistic window  24  (replacing the existing window) from both the threat side  13  and the non-threat side  15 . 
         [0035]    As depicted in the Figures, the classroom ballistic barriers of the present disclosure provide barrier-of-entry shielding that may be retrofit to the existing classroom door  11  by the school&#39;s own maintenance staff and will not inhibit emergency exits through the door  11 . The system and method of the present disclosure combines a minimally-thick ballistic skin  18  with a solid-core wood as is typically used as a classroom door  11  to create a shield equivalent to a N.I.J. Level IIIA ballistic panel. Hence, it is possible to retrofit a relatively thin ballistic skin  18  onto an existing door  11  to provide protection against multiple 0.44 magnum and 9 mm handgun blasts, as well as multiple 12-gauge shot gun blasts. The ballistic skin  18  may comprise ballistic fiberglass reinforced plastic (FRP) material. For N.I.J. Level IIIA protection, the door  11  and ballistic skin  18  combination, constituting the ballistic door  10 , must stop five rounds from a 0.44 magnum or five rounds from a 9 mm handgun within a 12″×12″ square shot 16 feet 4 inches away, with no penetrations. Normally, to achieve N.I.J. Level IIIA protection with this type of material, it would require a minimum of a ½″ thickness of FRP. Because FRP material weighs approximately 6 pounds per square foot, providing that thickness would add too much weight to the door  11 , would make it difficult for a single maintenance person to install, and would add unnecessary cost. However, by applying the ballistic skin  18  of a ¼″ thickness to an existing door  11 , the weight of the ballistic shielding is cut in half making it capable of installation by a single maintenance person, and the cost of the shielding is significantly reduced. Moreover, by using lightweight (thinner) ballistic material, the added weight will not fatigue the existing door  10 , nor will the shielding protection provided be exorbitantly expensive for schools, offices, or the like. The use of lightweight (thinner) ballistic material, while not surrendering ballistic integrity for the door, is possible by always placing the ballistic material on the non-threat side of the door. This enables the solid core wood door to assist with and perform some of the work if stopping bullets. 
         [0036]    In the exemplary embodiment shown in  FIGS. 1-4 , mechanical fasteners  32  are used to ensure that the ballistic door  10  will perform consistently against ballistic threats versus adhesive or double-sided adhesive tape. The adhesives suitable to secure the ballistic skin  18  to a typical classroom door  11  can vary greatly depending upon the substrate or substrate preparation. Hence, to use adhesives to secure the ballistic skin  18  to the existing door  11  can add unnecessary complexity to a retrofit installation. By using mechanical fasteners  32 , a residing maintenance worker for each school and/or office building is likely skilled sufficiently to install the ballistic skin  18  to the existing door  11 . Furthermore, because it is imperative that the ballistic performance not be compromised because of inattention to detail, retrofit installations using mechanical fasteners  32  is preferred. In short, the mechanical fasteners  32  make for a nearly fool-proof installation. 
         [0037]    The ballistic skin  18  is custom fit to each door  11  with an array of holes predrilled into the ballistic skin  18  enabling the installer to use the ballistic skin  18  as a drill template during installation. The array of holes are spaced from the outer boundary edges of the ballistic skin and the number and position of the holes assure that the ballistic performance is not compromised and the ballistic skin remains secured to the door during a gunfire attack. To permit the existing door  11  to properly close without the need for any modification of the existing door  11  or jambs (not shown, but see  FIGS. 11 and 12  for context), the ballistic skin  18  is held spaced from the peripheral edges  34  of the existing door  11  so that the outer boundary edges  36  of the ballistic skin  18  abuts the periphery of the jamb. Top and bottom ballistic skin clamps  20 ,  22  are provided to ensure a tight connection between the existing door  11  and the ballistic skin  18  without the need of any adhesives. As best seen in  FIGS. 1, 4, 9, 11, and 12 , the top ballistic skin clamp  20  is shown securing the ballistic skin  18  to the existing door  11  to preserve the peripheral spacing of the ballistic skin  18  from the peripheral edges  34  of the existing door  11  so that the outer boundary edges  36  of the ballistic skin  18  abuts the periphery of the jamb when the ballistic door  10  is closed. Similarly, as best seen in  FIGS. 1, 4, and 10-12 , the bottom ballistic skin clamp  22  is shown securing the ballistic skin  18  to the existing door  11  to preserve the peripheral spacing of the ballistic skin  18  from the peripheral edges  34  of the existing door  11  so that the outer boundary edges  36  of the ballistic skin  18  abuts the periphery of the jamb when the ballistic door  10  is closed. 
         [0038]    Ballistic fiberglass reinforced plastic (FRP) is difficult to bond to since it has a relatively “greasy” surface, so using mechanical fasteners  32  and the top and bottom skin clamps  20 ,  22  solve any bonding issues. The mechanical fasteners  32  may be tamper resistant through-bolts that are secured from classroom non-threat side  15  of the existing door  11 . In some embodiments, the use of sex-bolts ensures that the mechanical fastener  32  cannot be compromised from the hall or threat side  13  of the existing door  11 . 
         [0039]    It should be understood, however, that the systems and methods of the present disclosure may also be used in new construction and in total door replacement situations. In these types of installations, it may be preferable to use an adhesive attachment of the ballistic skin  18  to the existing door  11 . Those skilled in the art will understand what types of adhesives would be suitable. Also, in the instance of total door replacement, the residing maintenance worker is likely capable of installing the replacement door  10 , and in new construction, a qualified construction worker will handle the construction and hanging of the ballistic door  10 . 
         [0040]    If the existing door  11  has an inset window  16  as shown in the exemplary embodiment of  FIGS. 1-4 , the inset window  16  is replaced with a ballistic glazing or ballistic window  24  and a ballistic frame  26  so that the ballistic skin  18  overlaps at the joint  38  between the existing door  11  and the ballistic glazing or window  24 . See  FIG. 8 . The ballistic window  24  is fixed in place by the ballistic frame  26 , comprising both an interior frame portion  28  and an exterior frame portion  30 , to ensure that the ballistic protection extends over the entire ballistic door  10  area. Like the ballistic skin  18 , the ballistic frame  26  may be assembled and secured using mechanical fasteners  32 , such as sex-bolts bolts to ensure that the mechanical fasteners  32  cannot be compromised from the hall side of the existing door  11 . 
         [0041]    To shield the door latch  12  area of the existing door  11 , a latch guard  40  (hallway, threat side  13 ) and a latch support  42  (classroom, non-threat side  15 ) are incorporated to protect the ballistic door  10  against forced entry. An exemplary latch guard  40  is best shown in  FIGS. 2 and 5-7 , and an exemplary latch support  42  is best shown in  FIGS. 1 and 4-7 . 
         [0042]    With minimal alteration, the ballistic skin  18 , a modified latch guard  40 , and modified latch support  42  may be fit onto an existing door  11  that has panic hardware  44  or panic hardware  44  may be fit onto an existing door  11  that has been retrofit with this ballistic skin  18  to transform the existing door  11  into an alternative exemplary embodiment of a ballistic door  10  with panic hardware  44 . Those skilled in the art, armed with this disclosure would be able to make the minimal alterations to accommodate panic hardware  44 . Two exemplary alternative embodiments of ballistic doors  10  with alternative panic hardware  44  are shown in  FIGS. 11 and 12 . 
         [0043]    An exemplary method for preparing the ballistic assembly  17  for retrofit installation on an existing door  11  to be hung within a door jamb (see e.g.,  FIGS. 11 and 12 ) may include selecting a ballistic skin  18  having a thickness less than one-half inch and outer boundary edges  36 , the thickness of the ballistic skin  18  being sufficient, when secured to the non-threat side  15  of the existing door  11 , to create a ballistic door  10  having at least a N.I.J. Level IIIA of protection against gunfire. The ballistic skin  18  has a size such that the ballistic skin  18  is capable of being secured to the non-threat side  15  of the existing door  11  such that the outer boundary edges  36  are spaced from the peripheral edges  34  of the existing door  11  (see  FIGS. 1 and 4 ) and the outer boundary edges  36  abuts the periphery of the door jamb when the ballistic door  11  is closed. 
         [0044]    Once positioned as described above, an installer (whether a school&#39;s own maintenance staff worker or a qualified construction worker) may drill through-holes  50  through the existing door  11  by using the array of holes  46  in the ballistic skin  18  spaced from the outer boundary edges  36  as a template. See  FIGS. 1 and 4 . The array of holes  46  and corresponding through-holes  50  are positioned to assure that the ballistic skin  18  remains secured to the existing door  11  during a gunfire attack. For additional assurance that the ballistic skin  18  remains secured to the existing door  11 , a top ballistic skin clamp  20  and a bottom ballistic skin clamp  22  each having a length less than or equal to the horizontal (or width) dimension of the ballistic skin  18  may be selected and a plurality of holes  48  may be drilled through the top ballistic skin clamp  20  and the bottom ballistic skin clamp  22  to align with top and bottom portions of the array of holes  46  through the ballistic skin  18  along the top and bottom horizontal dimensions of the ballistic skin  18 , respectively, to align with the respective portions of the array of holes  46 . 
         [0045]    In some exemplary embodiments, the existing door may have an inset window  16 . In such cases, an exemplary method for preparing the ballistic assembly  17  for retrofit installation on an existing door  11  may include cutting away a portion of the ballistic skin  18  that would align with the size and location of the inset window  16  to create a window void  52 . A ballistic frame  26  having an interior frame portion  28  and an exterior frame portion  30  may be selected or made to have a size and shape to encase the window void  52  in the ballistic skin  18  and the inset window  16  in the existing door  11 . See  FIGS. 1, 2, 4, and 8 . A set of holes  51  may be drilled through the ballistic skin  18  spaced from and surrounding the window void  52 , and aligning holes  54  may be drilled in the internal frame portion  28  and corresponding external frame portion  30  to align with the set of holes  51  in the ballistic skin  18  that surround the window void  52 . A ballistic window  24  having a size and shape to replace the inset window  16  may be cut or selected such that it may be encased within the window void  52  in the ballistic skin  18  by the ballistic frame  26 . 
         [0046]    Whether the existing door  11  has an inset window  16  or not, it will have some type of door latch  12  having door knobs  14  or panic hardware  14 , for example. See  FIGS. 1, 2, 4-7, 11 , and  12 . Preparing a ballistic assembly  17  for retrofit installation on an existing door  11  with a door latch may require cutting away a portion of the ballistic skin  18  that would align with the size and location of the door latch  12  to create a latch void  56 , which may or may not include accommodating a dead bolt (not shown). A latch guard  40  may be secured to the threat side  13  of the existing door  11  to prevent jimmying the ballistic door  10  open manually or by gunfire. Also, a latch support  42  having a size greater than the latch void  56  may be secured to the non-threat side  15  of the existing door  11  to cover the latch void  56  in an overlapping fashion so that gunfire directly into the door latch  12  will not compromise the ballistic protection of the ballistic door  10 . 
         [0047]    An exemplary method of retrofit installation of a ballistic assembly  17  to an existing door  11  includes positioning a ballistic skin  18  having outer boundary edges  36  against the non-threat side  15  of the existing door  11 . The ballistic skin may have a size such that the ballistic skin  18  is capable of being secured to the non-threat side  15  of the existing door  11  in a manner that the outer boundary edges  36  are spaced from the peripheral edges  34  of the existing door  11 , and the outer boundary edges  36  abuts the periphery of the door jamb (not shown, but see  FIGS. 11 and 12  for examples of a door jamb) when the ballistic door  10  is closed. The ballistic skin  18  may have been prepped before installation, as described above, to have an array of holes  46  through the ballistic skin  18  that are spaced from the outer boundary edges  36  and positioned to assure that the ballistic skin  18  is capable of remaining secured to the existing door  11  during a gunfire attack. Also, as described above, the ballistic skin  18  may serve as a drilling template for drilling through-holes  50  through the existing door  11  that correspond to the array of holes  46  in the ballistic skin  18 . Once the through-holes  50  have been drilled, mechanical fasteners  32  may be secured through each hole of the array of holes  46  in the ballistic skin  18  and the corresponding through-holes  50  to secure the ballistic skin  18  to the non-threat side  15  of the existing door  11 . Also, in some exemplary embodiments, one mechanical fastener is secured through each hole of the plurality of holes  48  in the top ballistic skin clamp  20  and the bottom ballistic skin clamp  22  aligned with holes of the array of holes  46  and corresponding through-holes  50  to clamp the top ballistic skin clamp  20  and the bottom ballistic skin clamp  22  against the ballistic skin  18 . 
         [0048]    Where the existing door  11  has an inset window  16  and the ballistic skin  18  has a window void  52  with a set of holes through the ballistic skin  18 , the installer may replace the inset window  16  with a ballistic window  24  having a size and shape to replace the inset window  16 . The ballistic window  24  is held in place by encasing the ballistic window  24  within a ballistic frame  26  comprised of an internal frame portion  28  with aligning holes  54  to align with the set of holes  51  in the ballistic skin  18  that surround the window void  52  and an external frame portion  30  with aligning holes  54  to align with the set of holes  51  in the ballistic skin  18  that surround the window void  52 . The ballistic window  24  is secured within the ballistic frame  26  by applying mechanical fasteners  32  through each aligned hole  54  and each aligned hole of the set of holes  51  to secure the ballistic frame  26  about the ballistic window  24  and to clamp the ballistic frame  26  against the ballistic skin  18 . 
         [0049]    Additionally, the door latch  12  may be shielded against attack by securing latch guard  40  to the threat side  13  of the existing door  11  and securing a latch support  42  having a size greater than a latch void  56  in the ballistic skin  18  to the non-threat side  15  of the existing door  11  to cover the latch void  56  in an overlapping fashion. 
         [0050]    While specific exemplary embodiments, methods, and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise configurations and components disclosed herein. Various modifications, changes, and variations which will be apparent to those skilled in the art may be made in the arrangement, operation, and details of the methods and systems disclosed herein without departing from the spirit and scope of the invention.

Summary:
A ballistic door providing barrier-of-entry shielding blocks a doorway in certain emergency situations to shield against active shooters, while not inhibiting, impeding, or changing the safe egress through the ballistic door. A ballistic assembly may be secured to the non-threat side of an existing door, by retrofit installation or by new construction installation. The ballistic assembly has a ballistic skin, a top ballistic skin clamp, and a bottom ballistic skin clamp. The top and bottom ballistic skin clamps secure the ballistic skin against the non-threat side of the door. The ballistic door has at least a N.I.J. Level IIIA of protection against gunfire.