Friction surface means an interior or exterior surface that is subject to abrasion or friction, including, but not limited to, certain window, floor, and stair surfaces.
Impervious surface means a surface that has been covered with a layer of material so that it is highly resistant to infiltration by water.
Pervious surface means an area that releases as runoff a small portion of the precipitation that falls on it. Lawns, gardens, parks, forests or other similar vegetated areas are examples of surfaces that typically are pervious.
Emission limitation means a requirement established by the Board, the director or the Administrator, EPA, which limits the quantity, rate or concentration of emission of air pollutants on a continuous emission reduction including any requirement relating to the operation or maintenance of a source to assure continuous emission reduction (Section 302(k)).
Impact surface means an interior or exterior surface that is subject to damage by repeated sudden force such as certain parts of door frames.