The air change rate refers to the number of times the air within a controlled environment, such as a cleanroom or an HVAC system, is replaced or exchanged with fresh air per hour. It is a critical parameter used to quantify ventilation and airflow within a space, influencing air quality and contaminant control.

Yes, various organizations like ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers) and ISO (International Organization for Standardization) provide guidelines and standards for recommended air change rates based on the type of space, its function, and required air quality levels.