Air Systems Cleaning Specialist (ASCS) Practice Exam

According to cleaning standards, what should be done with fibrous glass duct insulation that has become wet in service?

1. Dried and cleaned

2. Cleaned and coated

3. Removed and replaced

4. Dried and sanitized

The correct answer is: Removed and replaced

When fibrous glass duct insulation becomes wet during service, it poses several issues regarding hygiene, energy efficiency, and the potential for mold growth. The correct course of action is to remove and replace the insulation entirely. This is essential because wet insulation can lose its thermal resistance properties, making it less effective at maintaining temperature and leading to increased energy costs. Additionally, wet insulation creates an environment conducive to microbial growth, which can contaminate the air circulated through the ductwork. Cleaning or attempting to dry the insulation may not fully restore its effectiveness and could inadvertently spread contaminants throughout the system. Coatings might not adequately address the underlying moisture issue, and sanitizing in this case would not be sufficient to ensure the safety and performance of the air handling system. Therefore, the best practice is to remove and replace the wet fibrous glass duct insulation to maintain the integrity of the HVAC system and ensure healthy indoor air quality.