Parking Garage Ventilation Calculator
Code airflow for an enclosed parking garage.
Enter your values
ⓘ Live results
Results
- Required exhaust
- 15,000 CFM
- Air changes
- 5
- Fans at 12,000 CFM each
- 2
- CO-controlled low speed (50%)
- 7,500 CFM
- Annual saving with CO control
- Often 50-80% of fan energy
Quick answer
Enclosed parking garages are commonly ventilated at 0.75 CFM per square foot of floor area.
CFM = area x 0.75
How to use the Parking Garage Ventilation Calculator
- 1Enter the enclosed floor area and clear height.
- 2Apply your local rate — 0.75 CFM per sq ft is the common default.
- 3Add CO and NO2 sensors so fans modulate instead of running flat out.
Worked example
Using the values the calculator loads with:
Inputs
- Garage floor area20000 sq ft
- Ceiling height9 ft
- Code rate0.75 CFM/sq ft
Results
- Required exhaust15,000 CFM
- Air changes5
- Fans at 12,000 CFM each2
- CO-controlled low speed (50%)7,500 CFM
- Annual saving with CO controlOften 50-80% of fan energy
Frequently asked questions
Is CO control allowed?
Most modern codes permit demand control down to a minimum, with sensors and alarms.
Where do exhaust points go?
Split between high and low level, since CO mixes but heavier vapours settle.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.