How much ventilation is required for mechanical systems in parking garages?

The correct answer, which states that 0.75 cubic feet per minute (cfm) of ventilation is required for mechanical systems in parking garages, reflects established guidelines to ensure adequate air quality and safety in enclosed spaces like parking garages. This ventilation rate is essential in controlling the buildup of vehicle emissions, such as carbon monoxide, which can be harmful to both human occupants and the integrity of the structure.

Industry standards, including those from organizations such as ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), typically recommend specific ventilation rates based on the risk of exposure to harmful pollutants emitted from vehicles. The figure of 0.75 cfm helps in diluting concentrations of these pollutants, thereby enhancing the air quality for anyone using the garage.

This ventilation standard balances the need for safety with energy efficiency, providing enough airflow to mitigate risks without being unnecessarily excessive, which could lead to increased operational costs.

In contrast, the other options given do not align with these established guidelines. Higher values, such as 1 cfm or 2 cfm, might suggest an over-ventilation scenario that could lead to wasted energy and increased operational expenses without providing significantly better air quality. Meanwhile, 1.5 c