What is the function of negative pressure in containment during asbestos work?

• A. It reduces humidity
• B. It increases the risk of leakage
• C. It helps limit dispersion by drawing air into the containment from adjacent areas
• D. It dries surfaces quickly

Answer: (C)

Negative pressure inside containment draws air from adjacent, cleaner areas into the containment, which helps keep asbestos-containing air from leaking into the rest of the building. By exhausting air through a HEPA-filtered system and balancing with make-up air, the containment remains at a lower pressure than surrounding spaces, so any small gaps pull air inward rather than push contaminated air outward. This inward airflow is the key to preventing dispersion of asbestos fibers during work.

Humidities or drying of surfaces aren’t the function of negative pressure, and a higher pressure in surrounding areas would be more likely to push air out of the containment, increasing the risk of spread.