Negative Pressure - Explained
Negative pressure is quite simple. In this example, a bedroom will be our containment. Our bedroom has only 1 entrance and 1 window. An air scrubber, capable of filtering all of the air 4 - 30 times per hour, is placed inside containment. The exhaust (filtered air) is ducted directly from the air scrubber to the window where it is exhausted outside. Therefore, a large quantity of air is being taken outside of our containment. All of the air being deposited outside must be made up. This "make-up" air can only come from 1 location in this sealed environment - the bedroom door. Thus, a large volume of air is being rushed inside containment through the door, filtered, and deposited outside. There is no way particles (mold spores, dust, demolition debris) can make its way through that same door and "contaminate" the rest of the facility. If this theoretical room was made of plastic walls, all of the walls would be sucking in at an alarming rate, thus causing negative pressure