Typical building carpet is not designed to capture and hold particulates, so it is not considered a compliant entryway system under this credit. Remember that the intent of this credit is to improve indoor air quality by preventing the introduction of pollutants into the building interior. Most carpet simply isn’t designed with this in mind. Unless you can provide compelling documentation from a manufacturer that shows your carpet is designed to effectively capture dirt, pollen and other particulates, you won't be eligible for this credit.