Definition
An enclosed work area built from polyethylene sheeting and sealed to prevent asbestos fibers from escaping during removal. It includes barrier walls, airlocks, decontamination units, and a negative air pressure system. Containment integrity must be maintained throughout the project and verified by air monitoring and visual inspections.
See also:
Decontamination Unit
A set of connected chambers through which workers pass when entering or leaving an asbestos work area. The sequence runs: dirty room (removing contaminated PPE), shower room (washing), clean room (putting on clean clothes). Workers who skip or shortcut the sequence carry fibers out of the work area with them.
Negative Air Unit (NAU)
A ventilation system with HEPA filters that maintains negative air pressure inside an asbestos work area, so contaminated air cannot escape. The unit draws air continuously from the work area, passes it through HEPA filters, and exhausts clean air outside. Incorrect placement or operation allows contaminated air to leak, putting workers and nearby occupants at risk.