What must a conduit that is vented outdoors be able to prevent from entering?

A conduit that is vented outdoors must be designed to prevent the entry of water and insects. This requirement is critical to ensure the integrity and functionality of the system it serves. If water were to enter the conduit, it could lead to corrosion, mold growth, or other environmental issues that might compromise the safety and effectiveness of the venting system. Similarly, the intrusion of insects could obstruct airflow or cause blockages that impair the vent's performance, potentially leading to hazardous conditions. Therefore, protecting against both water and insects is essential to maintain the system's reliability and safety when venting outdoors.