Smoke outlet tubes in garages, installation

This article discusses the factors to consider when installing smoke outlet tubes in garages. It is important to note that ventilation systems play a fundamental role in ensuring the safety of individuals, as they guarantee the proper extraction of smoke in the event of a fire. The regulations governing the principles of ventilation in garages and other parking structures are outlined in the Technical Building Code.

As stated in point 1.1, the CTE DB HS 3, Indoor air quality, this section applies to “in residential buildings, within them, waste storage areas, storage rooms, parking lots and garages; and in buildings of any other use, to parking lots and garages. The circulation areas for vehicles are considered to be part of the parking lots and garages.”

Supply and extraction flow rate

According to section 3.1.4, “Parking lots and garages must have a ventilation system that can be either natural or mechanical.” In accordance with the Code, the minimum ventilation flow rate in parking lots and garages is 120 l/s per parking space (or, equivalently, 432 m3/h). For practical purposes and calculations, it is estimated that two motorcycle parking spaces are equivalent to one car parking space.

Smoke outlet tubes in parking lots, how should ventilation work in case of mechanical ventilation?

The requirements of the following regulations for ventilation of parking lots by mechanical means are as follows:

Compartmentalization

The ventilation of parking areas cannot be shared with other premises (unless storage rooms are already part of the parking area itself). In any case, despite being able to share ventilation, according to CTE DB SI, Fire safety, the compartmentalization of storage rooms as a special risk area must be respected, if that were the case.

In the case of compartmentalized parking lots that share ventilation, the intake openings will be located in those compartments and the extraction ones in the collective circulation areas. Thus, each of the compartmented spaces will have, at minimum, one intake opening.

Depression

Ventilation (whether only extraction occurs mechanically or if both intake and extraction occur) must be achieved through depression. In any case, mechanical fans must be installed in accessible areas for proper cleaning and maintenance.

Intake and extraction openings

To prevent the stagnation of harmful gases, intake and extraction openings must be provided for every 100 m2 of usable area. Additionally, the distance between the closest extraction openings should not exceed 10 meters.

Distances

At least two out of every three extraction openings will be located at a distance from the ceiling that does not exceed half a meter.

Duct layouts

When parking areas have 15 spaces or exceed this number, each floor of the building must have two extraction duct layouts, with the corresponding mechanical extractor.

CO2 Detector

In the case of parking premises housing more than five spaces, or exceeding 100 m2 of usable area, the installation of a CO2 detector is mandatory on each floor. In this way, when it reaches 50 ppm (if employees are present) or 100 ppm (if there are none), the device will activate.