DPC stand for Damp Proof Course. DPC is applied in the base level to protect the structure from the ill effects of moisture and dampness. Thus damp proof course helps in preventing water and moisture to damage the walls and interior of home.
Read this extensive article on standard height of plumbing fixtures that should be known while planing and constructing your bathroom.
FSI or Floor Space Index refers to permissible maximum area that can be constructed on a given plot area. It is also denoted by FAR or Floor Area Ratio.