Air Systems Cleaning Specialist (ASCS) Practice Exam

Dirt streaks around supply diffusers that are not caused by a dirty ventilation system are likely caused by what factor?

1. Slow discharge velocities

2. Elevated relative humidity

3. Dirty room air at the diffuser

4. Thermal stratification around the diffuser

The correct answer is: Dirty room air at the diffuser

The presence of dirt streaks around supply diffusers typically suggests that particles in the air are settling around the area, leading to visible residues. When considering the environments where these diffusers operate, dirty room air is a significant factor. If the air entering the diffuser contains dust, pollen, or other particulates, these particles can accumulate on surfaces around the diffuser, creating noticeable streaks. This context helps clarify the importance of maintaining cleanliness in the room's environment itself and suggests that source control for indoor air quality is crucial. When a room has high levels of pollutants in the air, even a well-maintained ventilation system may struggle to prevent the buildup around diffusers. This makes managing the cleanliness of the indoor environment essential for preventing dirt accumulation, making the selection of dirty room air at the diffuser the most relevant choice.