Ventilation in parking lots, what does current regulation say?

It should be noted that the applicable ventilation regulations will vary depending on the use for which a building is intended. Thus, we will apply the CTE DB HS3 Quality of indoor air “in residential buildings, inside them, waste storage areas, storage rooms, parking lots, and garages; and, in buildings of any other use, to parking lots and garages. Circulation areas for vehicles are considered part of parking lots and garages. For commercial premises of any other type, it is considered that basic requirements are met if the conditions established in the RITE are observed.” In this article, we explain the requirements regarding ventilation in parking lots.

Ventilation in parking lots: natural ventilation and mechanical ventilation

According to current regulations, buildings intended for parking, as well as garages, must have a ventilation system, whether natural or mechanical.

Requirements for natural ventilation

If we intend to renew the air in the building through natural ventilation, we must have mixed openings in two opposite areas of the envelope, at a minimum, so that their distribution is homogeneous and the distance between any point in the enclosure and the nearest opening does not exceed 25 meters (throughout the route and without obstacles).

For parking buildings with five spaces or fewer and a usable area that does not exceed 100 m2, one or several admission openings (at the bottom of one of the enclosures) that connect directly with the outside space can be provided, along with one or several extraction openings (at the top) with a vertical distance of at least 1.5 meters.

Requirements for mechanical ventilation

Ventilation must be exclusively for parking, unless storage rooms are located within the parking lot itself (ventilation can be joint).

Ventilation will occur through depression, using one of these two options:

• Air admission occurs through natural means and extraction through mechanical means (simple flow mechanical ventilation).
• Both admission and extraction occur through mechanical means (double flow mechanical ventilation).

It must be ensured that stagnant pollutants do not occur. To achieve this, ventilation openings in parking lots must meet the following requirements:

• For every 100 m2 of usable area, there must be one admission opening and one extraction opening.
• The separation between the nearest extraction openings cannot exceed 10 meters.

At least two out of every three extraction openings must be located at a distance from the ceiling equal to or less than 50 cm.

If the parking lot is compartmentalized and ventilation is conducted jointly: compartments must have, at a minimum, one admission opening, and the common circulation areas must have extraction openings.

For parking floors that accommodate 15 vehicle spaces or more, two extraction duct networks (with the corresponding mechanical extractor) must be installed per floor.

In enclosures that accommodate five vehicles or more, or where the usable area exceeds 100 m2, a carbon monoxide detection system must be installed on each floor, so that mechanical extractors are automatically activated if the concentration reaches 50 ppm (in parking lots with employees) or 100 ppm (in parking lots without employees).