Sheet Metal Journeyman Practice Test

Screen openings on intakes regulate how much air can enter while controlling what can be drawn in or clog the system. In non-residential occupancies, the standard allows a maximum opening of 1 inch. This size provides enough airflow for commercial HVAC needs without permitting excessively large debris or objects to be pulled in, while still being practical for screening methods used in these buildings. If openings were larger, bigger debris or pests could enter and affect performance; if they were smaller, airflow would be unnecessarily restricted and could lead to more maintenance.