What is the maximum size allowed for wire rodent/insect mesh at the exhaust?

The correct answer is 1/2 inch. This size is effective for preventing rodents and insects from gaining entry through exhaust systems, while still allowing for adequate airflow. A mesh size of 1/2 inch is a standard practice in many mitigation protocols, as smaller openings can help inhibit pest access more effectively without obstructing exhaust functionality.

Larger mesh sizes, such as 3/4 inch or 1 inch, would not provide the necessary deterrent for smaller pests and could allow them to pass through, negating the protective purpose of the mesh. While a 1/4 inch mesh could theoretically work, it may restrict airflow excessively, which could lead to ventilation issues in systems relying on proper exhaust. Therefore, 1/2 inch is widely considered the optimal balance between pest prevention and maintaining system efficiency.