a self contained portable negative pressure control system enclosure for protection from airborne asbestos particles and the like from a work space includes an enclosure formed of portable rigid door frames having spring doors and a weighted transom closure within that communicate with the work space to define multiple non - sealed decontamination chambers . the enclosure is used with a room divider or in an access doorway to the work space which is maintained in a negative air pressure by exhaust blowers equipped with hepa filters .