The International Mechanical Code (IMC) is the model code for mechanical systems, including heating, ventilation, air conditioning and exhaust, published by the International Code Council.
For parking, its most important provisions cover ventilation of enclosed parking garages. An enclosed garage must be mechanically ventilated, and the IMC sets the exhaust rate and allows systems to run at a reduced rate when gas detection shows the air is clean. Open garages that meet the building code’s openness tests rely on natural ventilation instead. See open parking garage.
Garage ventilation under the IMC
- A full exhaust rate for enclosed parking garages, stated in cubic feet per minute per square foot.
- Demand-controlled operation with carbon monoxide and nitrogen dioxide detection, which lets fans drop to a much lower minimum rate when readings are low. See demand-controlled ventilation.
- Exhaust and makeup air arrangements that sweep the whole floor without dead zones.
The Parkonomics view
Garage ventilation is a code requirement with a large energy bill attached. Demand control under the IMC can cut fan energy dramatically, but only if the sensors and controls are commissioned and maintained.
Related terms: Mechanical Ventilation System, Demand-Controlled Ventilation, Enclosed Parking Garage, CFM, I-Codes