Plastic Grilles, do you know where they should be located?

In volume 63 of Construction Reports, published by the Institute of Construction Sciences Eduardo Torroja (CSIC), special emphasis is placed on the importance of correctly locating the openings (and therefore, all types of grilles, whether plastic grilles or metal grilles) if an efficient ventilation system is sought.

Location of grilles and efficiency: an intimate relationship

"Ventilation," according to current regulations, consists of the following: firstly, providing a closed room with the necessary amount of clean air and extracting from it the stale and contaminated air, always through the enclosure. Secondly, distributing that air and making it circulate to avoid indoor pollution. For this, air penetrates through the bottom gap of a door and exits the room through a similar opening located opposite it. This system, however, creates large areas of stagnant air (air that has not been renewed), leading us to think that this system is not sufficient and we should consider the option of installing a controlled mechanical ventilation system.

Each case must always be studied carefully to optimize the system used. It should be noted that the more efficient our ventilation system is, the more energy savings there will be, and therefore, economic savings. Buildings consume 40% of the total energy consumed, and this is partly due to losses caused by uncontrolled air infiltration.

Whether we have a natural, hybrid, or mechanical air supply system, when designing a building, professional advice must be sought to locate the intake and extraction openings where they are most efficient, so that the desired air renewal occurs while consuming the least amount of energy possible. But what do we mean by efficiency? Efficiency of air renewal in a room is understood to be the relationship that exists between the least possible time it takes to replace the interior air of a room (minimum renewal time) and the average time spent in carrying out this action (average air renewal time).

Intake grilles

Whether fixed or adjustable, they will be installed at least 1.80 meters above the ground. In the case of hybrid ventilation, the intake grilles will communicate directly with the outside.

Extraction grilles

They will be connected to extraction ducts at less than 2 meters from the ceiling; and at a distance of any corner greater than 1 meter.

Exhaust grilles

In the case of grilles that crown the exhaust outlets, they will be on the roof, at least 3 meters away from any ventilation inlet. If the ventilation is hybrid, the exhaust grille will be located 1 meter above the roof. All ventilation grilles, whether plastic or any other material, that come into contact with outside air must be arranged in such a way that water cannot enter in case of rain, or failing that, must have elements that prevent it.