Air Systems Cleaning Specialist (ASCS) 2025 – 400 Free Practice Questions to Pass the Exam

In contaminated air duct systems, fibrous glass and polystyrene are commonly involved due to their widespread use as insulation materials within HVAC systems. These materials can become sources of contamination over time, particularly when exposed to moisture or biological growth.

Fibrous glass, often used for insulation, can trap dust, debris, and microbial contaminants in its fibers, creating an environment conducive to mold and bacteria. When disturbed during cleaning or maintenance, these contaminants can be released back into the air stream, highlighting the importance of cleaning processes that can effectively manage these materials.

Polystyrene, often found in foam insulation, can degrade or accumulate dust and contaminants as well. These two materials contribute significantly to potential air quality issues when not properly maintained.

The other materials listed – plywood, metal, concrete, brick, plastic, and rubber – are not typically associated with the same level of contamination risk in air duct systems as fibrous glass and polystyrene. While they may be part of the structural elements of a building or components of duct systems, they do not harbor contaminants in the same way that fibrous insulation materials do.