Carpet tile is now an acceptable entryway system per LEED Interpretation Ruling ID#10252 https://www.usgbc.org/leedinterpretations/LISearch.aspx?liaccessid=10252
Carpet tile is a highly desired walk-off mat due to its ease of maintenance as compared to mechanical systems, avoidance of trip hazards associated with roll-out mats, and many other factors. Carpet tile captures and hides soil, requires minimal maintenance and helps prevent slips and falls. The solid backing prevents soil and moisture from penetrating the tile and seams. Carpet tiles allow for easy replacement of damaged tiles.
The carpet tile must be specifically designed for entryway systems, conventional carpet is not acceptable.