What must all outside combustion air openings be protected with?

Outside combustion air openings must be protected with a screen that has a mesh size not smaller than 1/4 inch. This requirement is crucial for ensuring that the air entering the combustion chamber is free from larger debris and particles, which could interfere with the combustion process and potentially damage the equipment.

Using a screen of 1/4 inch mesh strikes a balance between allowing sufficient airflow for combustion while preventing larger items like leaves, twigs, or small animals from entering the system. This is particularly important in commercial food service operations where equipment must maintain consistent performance and efficiency for safe food preparation.

Implementing this screen protection not only enhances optimal functioning but also contributes to safety standards by minimizing the risk of blockages or hazards associated with foreign objects in the inlet air pathway. The correct sizing ensures that the air needed for combustion is not restricted, which could lead to poor performance or unsafe operating conditions.