What is the purpose of installing a single layer of 6 mil poly as part of the 'Other critical barriers'?

• A. To prevent contaminated air from escaping from the work area.
• B. To improve lighting.
• C. To provide thermal insulation.
• D. To dampen sound.

Answer: (A)

The main idea here is containment of contaminants. Installing a single layer of 6 mil poly as part of the other critical barriers creates a physical enclosure that helps stop contaminated air and dust from moving out of the work area. When the poly is sealed at the seams and edges, it reduces leakage paths and supports maintaining a controlled environment (often with negative pressure) so nearby spaces aren’t contaminated. It’s not about lighting, insulation, or sound, which would require different materials. A single layer is a practical, common choice for temporary containment, provided it’s properly taped and secured to maintain the barrier.