When must a decontamination unit be kept under negative pressure?

A decontamination unit must be kept under negative pressure at all times until a final clearance sample is passed to ensure the safety and health of workers and occupants in surrounding areas. Negative pressure helps contain any airborne asbestos fibers within the decontamination unit, preventing them from escaping and infiltrating other areas. This containment is crucial throughout the entirety of the asbestos abatement process, as there is a continuous risk of fiber release until the site is confirmed to be free of asbestos hazard, which is established through the successful passing of final clearance sampling.

While it might seem that negative pressure is only necessary during certain activities like removal or waste disposal, maintaining it at all times until clearance ensures comprehensive safety measures are in place, protecting both workers and the environment from potential asbestos exposure. This practice is part of strict compliance with safety regulations and standards designed to minimize the risk of asbestos-related diseases.