Each tier of an open parking garage must have what percent open to the atmosphere?

In an open parking garage, it is essential for each tier to have a significant percentage of its structure open to the atmosphere to ensure proper ventilation. This design helps to mitigate the buildup of harmful fumes from vehicles and assists in maintaining safe levels of air quality within the garage.

The requirement for 40% of the tier to be open to the atmosphere strikes a balance between structural integrity and air circulation. This percentage allows for adequate airflow, which is critical in preventing the accumulation of carbon monoxide and other vehicle emissions that could pose a safety risk to individuals using the facility. The need for such ventilation is particularly important in areas where vehicles are consistently parked or running, as it minimizes the hazard of toxic exposure.

Understanding this aspect of design helps in recognizing why open percentages are mandated and ensures safety and compliance with building codes for parking structures. The options that reflect lower percentages may not provide sufficient ventilation, while anything above 40% could compromise the structural safety and stability of the parking tiers.