What is a requirement for air intake and exhaust systems?

The requirement indicating that all air intake and exhaust systems must adhere to specific guidelines, while clothes dryer exhaust systems are excluded from needing a screen, reflects safety and functionality standards. Clothes dryer exhaust systems are understood to carry lint and other debris, requiring a free-flowing exit to mitigate fire hazards. Therefore, it's important that these systems operate without additional restrictions such as screens.

In contrast, other air intake and exhaust systems benefit from screens as they help protect against pests, debris, and other contaminants entering the system, thus enhancing performance and safety. Since clothes dryer exhaust systems have unique operational needs, exceptions are made for them, reinforcing the idea that different systems have tailored requirements based on their specific applications and operational contexts.