What minimum negative pressure must be maintained at all times?

The correct answer indicates that a minimum negative pressure of -0.02 inches of water must be maintained at all times during asbestos operations. This requirement is crucial for ensuring that airborne asbestos fibers do not escape the work area and compromise air quality.

Maintaining a negative pressure helps to create a controlled environment that prevents contaminant migration. In the case of asbestos abatement, it's essential to ensure that the air flows into the work area rather than out of it, which means that any potential asbestos fibers remain contained within the designated space. The specified -0.02 inches of water is a standard threshold designed to protect both workers and surrounding individuals from asbestos exposure.

While other negative pressure values may be listed, only -0.02 inches of water aligns with regulatory standards aimed at providing a safe working environment during asbestos-related activities.