Automatic operation of the system shall not reduce the ventilation airflow rate below how many cfm per square foot of the enclosed parking garage floor area?

The correct answer is based on the standards for ventilation rates in enclosed parking garages, which are established to ensure adequate air quality and safety for occupants. The requirement for a minimum ventilation airflow of 0.05 cubic feet per minute (cfm) per square foot of the enclosed floor area is intended to dilute contaminants such as carbon monoxide and other harmful gases generated by vehicle emissions.

This ventilation rate is crucial for maintaining a safe environment, as it helps to prevent the accumulation of hazardous pollutants that could endanger the health and safety of individuals using the garage. Establishing a lower limit ensures that no matter the operational status of the mechanical systems or natural airflow conditions, there is a baseline level of ventilation that must be maintained to promote health and safety.

Higher airflow rates, such as 0.5 cfm, 5 cfm, or 50 cfm per square foot, are not typically required for enclosed parking garages and may lead to energy inefficiencies or increased operational costs, which is why they are not designated as the minimum standard in this context. Therefore, maintaining at least 0.05 cfm per square foot effectively balances safety, functionality, and cost.