Try to prevent as much soil as possible from tracking into the building by using entrance mats. Where practical, 2 linear metres of barrier matting should be installed at entrances, allowing at least two paces over which soil from shoes may be walked off. Make sure that the matting itself is regularly cleaned, otherwise a soil reservoir is created which can be counter-productive. Smaller size secondary matting either loose laid or inlaid, will provide a second line of defence, and help to prevent abrasive grit and other soil particles entering the building.
Thorough regular vacuuming is probably the most effective means by which carpet appearance can be maintained, as this not only removes soil and grit, but helps prevent premature matting. For cut pile carpets, an upright vacuum cleaner incorporating a brush and beater bar will be most effective, but for loop pile carpets, a suction-only vacuum should be used. In both cases, make sure the vacuum is regularly checked to ensure it is functioning effectively and efficiently.