TM 1-1500-204-23-1 Table 9-6.  Armor Plating Definitions Terms Definitions Panel Each individual removal unit or module of the total assembled armor protective system. Delamination Any area where the fiberglass ply or plies have become detached from the binding resign in the reinforced plastic backing. Backing The ballistic energy absorber and structural support system for the brittle ceramic tile.  The backing is a composite of fiberglass lamination impregnated with plastic resign. Spall Shield A cover on the ceramic tile to protect crew members from flying fregments during a ballistic impact.  The spall shield is made of nylon cloth MIL-C-12369. (1) Inspect    for    the    following    damages    which cannot  be  repaired  In  the  following  substeps  (a)  and  (b), the  allowable  deviation  is  zero;  therefore  the  panel  must be    scraped.        In    the    Note    following    substep    (c)    an acceptance tolerance is specified, therefore, do not scrap panels that are within the allowable tolerance Send panel to a higher level of maintenance for repair. (a) Inspect all panels for ballistic damage.    Do  not  repair  armor  panels  with  any  ballistic damage (direct hit). (b) Inspect for cracked resign or ridges in the backing that show evidence of a structural failure. NOTE This  damage  will  be  matched  by  a  tile crack   generally   paralleling   the   failure line  in  the  backing  This  damage  may occur  at  a  weaker  reduced  sections  of the  panel,  such  as  the  area  around  the head   Accidental   blows   from   tools   or hard   objects,   and   the   use   of   armor panels   as   handholds,   are   usually   the cause  of  this  type  of  damage  Do  not repair   armor   panels   with   any   cracked resin or ridges In the backing (c) Inspect the panel for unbonded tiles NOTE To  check  for  unbonded  tile  on  armor having multiple tile sections, lightly tap the  ceramic  surface  using  a  coin  Any area that has a lack of bond between the tile and plastic backing should respond with   a   dull   thud,   as   opposed   to   the higher  pitched  sound  of  a  well  bonded area  However,  the  distinction  between the bonded and unbonded area will not always be clearly evident NOTE To   determine   a   characteristic   sound, compare  with  a  well-bonded  area,  such as along a panel edge.  Press firmly by hand all over the tile surface, observing any  tile  movement  on  release  of  hand pressure.    Outline  any  unbonded  area on  the  face  of  the  tile  for  reference  A 100    percent    bond    between    tile    and backing    Is    not    required    for    ballistic efficiency.    Do  not  make  allowance  for any additional support of the tile by the spall shield.  Do not repair armor panels having a total unbonded area In excess of  20  percent  for  each  tile  section  For monolithic  armor  (one  piece  cast  tile), the   tile   bond   as   a   whole   should   be adequate . 9-49