ICC Commercial Mechanical Practice Exam

What is the maximum air temperature allowed within nonmetallic ducts?

1. 108°F

2. 212°F

3. 250°F

4. 350°F

The correct answer is: 250°F

The maximum air temperature allowed within nonmetallic ducts is indeed 250°F. This limit is established to ensure safety and prevent damage to the duct material, which can be adversely affected if temperatures exceed this threshold. Nonmetallic ducts, often made from materials such as PVC or fiberglass, can lose structural integrity or become deformed if exposed to excessively high temperatures. Moreover, maintaining temperatures within this range helps reduce the risk of combustion, particularly in settings where flammable materials may be present. The other temperature options are not permissible for nonmetallic ducts. Specifically, 108°F is well below the operational limits, while both 212°F and 350°F are above the acceptable range for nonmetallic materials, increasing the potential for damage and safety hazards.