What is the required outdoor air CFM for a two-car garage in a single-family dwelling unit?

What is the required outdoor air CFM for a two-car garage in a single-family dwelling unit?

• A. 200 CFM
• B. 100 CFM
• C. 300 CFM
• D. 400 CFM

Answer: (A)

Providing outdoor air to an attached garage helps dilute vehicle exhaust and other fumes that can migrate into the living space. The code often bases the required outdoor-air rate on the number of vehicles in the garage, typically using about 100 CFM per vehicle. With two vehicles, that adds up to 200 CFM. This ensures the garage has enough fresh air to keep pollutant levels low, even with vehicles running or fumes present. If there were only one vehicle, about 100 CFM would be required; more vehicles would proportionally increase the needed outdoor air.

Providing outdoor air to an attached garage helps dilute vehicle exhaust and other fumes that can migrate into the living space. The code often bases the required outdoor-air rate on the number of vehicles in the garage, typically using about 100 CFM per vehicle. With two vehicles, that adds up to 200 CFM. This ensures the garage has enough fresh air to keep pollutant levels low, even with vehicles running or fumes present. If there were only one vehicle, about 100 CFM would be required; more vehicles would proportionally increase the needed outdoor air.