Filtration Soil Information
Soiling around the Edges
 

I get this call all the time: "The last carpet cleaner didn't do a good job..there is still a dark line around the edge of my carpet".  This "line" is called Filtration and it's time to get your HVAC system cleaned.

Filtration soil is a term used to describe dark, grayish lines that may appear on carpet. Filtration soil areas may appear around baseboards, under doors, along the edges of stairs and possibly away from walls where plywood subflooring materials have been joined. Generally, the concentrated air flow will be from an upper level to a lower level of the home. Filtration Soiling Dark grayish lines under doors, around baseboards, and along edges of stairs are symptoms of an aggravating problem -- Filtration Soiling. The cause of the problem is really quite simple: Dust, smog, and other airborne pollutants accumulate where concentrated airflow is directed over or through the carpet's pile. The carpet 'filters' out these pollutants and gradually becomes discolored. The soiling condition can occur quickly, or it may develop over a period of months or years. The level of soiling is dependent upon the volume of airflow and the level of pollutants in the air.


 

Illustrations reprinted by permission from the Carpet and Rug Institute.