What type of screen is required for air inlets from outside the building serving residential occupancies?

The requirement for a screen mesh on air inlets from outside the building serving residential occupancies is determined by the need to prevent the entry of pests while allowing adequate airflow. A mesh size of 1/4-1/2 inch is the standard specified to balance these needs effectively. This size is small enough to keep out insects and debris while still allowing for sufficient air circulation, which is crucial for ventilation in residential environments.

Having a properly sized screen ensures that it does not restrict airflow significantly, which could lead to issues with indoor air quality and the efficiency of heating and cooling systems. Additionally, if the mesh were to be too fine, it might restrict airflow more than desirable, while a larger mesh could allow unwanted pests to infiltrate the space.

In summary, a screen mesh size of 1/4-1/2 inch is appropriate for residential air inlets as it addresses both ventilation requirements and the need for pest control.