Andy In Cover Taking Fire Debri

I have been working on the shot of my actor taking fire while being in cover, I have to create accurate debri explosions as the incoming bullets break of dirty and concrete from the wall. To do this i made my own 3D wall environment and scaled it to that of the real time footage. I then created my own Debri animations by creating various shaped polygons and then animating them quickly to give the sens of quick motion. Below is a screenshot of my workspace which also shows how I was trying to create my 3D Environment accurately.