Control system for doors of a negative air pressure enclosure

A door for entry to and exit from an asbestos containing work area, from which asbestos contamination is removed under negative air pressure conditions, said door comprising:

• a rigid frame for pivotal mounting in a doorway for access to said asbestos containing work area;
• said frame having an air inlet for passage of substantial volumes of air therethrough under the effect of negative air pressure in said work area caused by an air moving and filtration means;
• and
• rigid sealing means pivotally mounted on said frame for sealing said inlet automatically upon loss of said negative air pressure in said work area.

A system for controlling air flow in an area where contaminated asbestos materials are being removed from a building, said system comprising:

• an enclosed work area surrounding where asbestos contamination is being removed;
• a rigid door pivotally mounted adjacent the work area for swinging movement during worker access into and out of the work area;
• means for establishing at least one air flow inlet opening from outside the enclosed work area into said enclosed work area;
• at least one air moving and filtration unit for filtering air in the work area, for producing a negative air pressure in the work area, and for drawing air into the work area through said air flow inlet opening;
• and
• means for automatically closing said air flow inlet opening upon sensing a fire, smoke or other emergency within said building.

A method for controlling air flow in an area where contaminated asbestos materials are being removed from a building, which comprises:

• constructing an enclosed space surrounding an area where asbestos contamination is to be removed;
• providing worker access into and out of said enclosed space through a rigid door pivotally mounted for swinging movement;
• establishing at least one air flow inlet through said rigid door from outside the enclosed space into said enclosed space;
• continuously evacuating substantial volumes of air from said enclosed space through a HEPA filter means and continuously drawing substantial volumes of air into said enclosed space through air flow inlet opening to remove dangerous airborne asbestos fibers in said enclosed space and to establish a negative air pressure in said enclosed space;
• and
• automatically closing said air flow inlet opening upon loss of negative air pressure in the enclosed space or other command signal due to changed conditions within said building.

A decontamination chamber for providing worker access between an enclosed work area, where contaminated asbestos materials are being removed from inside a building, and a relatively clean environment outside the work area, which chamber comprises:

• at least a clean room and dirty room through which workers must pass in order to gain entrance to and exit from said enclosed work area;
• a rigid door mounted in a doorway for access to the clean room from the outside environment;
• a rigid door pivotally mounted in a doorway between the clean room and dirty room;
• both said rigid doors providing at least one air flow inlet opening through which substantial volumes of air from the outside environment can sweep through the decontamination chamber into the enclosed work area;
• and
• means for automatically closing said air flow inlet openings upon loss of negative air pressure in the enclosed space.

A negative pressure enclosure for a work area in which dangerous solid asbestos contamination is being removed which comprises:

• wall means including a portion of the existing wall structure in said building and temporary wall means erected to complete the enclosure;
• a rigid door pivotally mounted in said temporary wall means for swinging movement during worker access into and out of the enclosure;
• means for establishing at least one air flow inlet opening from outside the enclosed work area into said enclosed work area;
• at least one air moving and filtration unit for filtering air in the work area, for producing a negative air pressure in the work area, and for drawing air into the work area through said air flow inlet opening;
• and
• means for automatically closing said air flow inlet opening upon sensing a fire, smoke or other emergency within said building.

An air inlet and sealing means for providing air flow into an enclosed negative air asbestos removal work area, which comprises:

• an air flow inlet opening in a temporary wall erected for constructing said enclosed work area;
• said air flow inlet opening capable of allowing substantial volumes of air to pass from outside said work area into said work area under the effect of negative air pressure in said work area caused by an air moving and filtration means;
• and
• rigid sealing means pivotally mounted for sealing said air flow inlet opening automatically upon loss of negative air pressure in said work area or other command signal due to changed conditions within said building.