What regulations must the air diffusers of your ventilation system comply with?

Do you know the regulatory requirements of the state regarding air diffusers? Below, we will explain what both RITE (Regulation of Thermal Installations in Buildings) and CTE (Technical Code of Building) establish.

The large family of air diffusers

• Ventilation opening: gap made in one of the construction elements that delimit a room to allow the transfer of air between it and another adjacent room or the outside space.

• Supply opening: ventilation opening that serves for supply, communicating the room with the outside, directly or through a supply duct.

• Extraction opening: ventilation opening that serves for extraction, communicating the room with the outside, directly or through an extraction duct.

• Passage opening: ventilation opening that serves to allow the passage of air from one room to another.

• Exhaust outlet: exterior end of an extraction duct through which the stale air exits, which is equipped with protective elements to prevent the entry of water and birds.

• Inlet opening: exterior end of a supply duct through which outside air enters, which is equipped with protective elements to prevent the entry of water and insects.

How many regulations do you think influence the design of air diffusers?

• Supply openings: 4 × qv   or 4 × qva
• Extraction openings: 4 × qv   or 4 × qve       
• Passage openings: 70 cm2   or 8 × qvp    
• Mixed openings: 8 × qv   

• qv is the minimum required ventilation flow of the room (l/s), obtained from the table.

• qva is the ventilation flow corresponding to each supply opening in the room calculated by a balancing procedure for supply and extraction flows and with a hypothesis of air circulation according to the distribution of the rooms, (l/s).

• qve is the ventilation flow corresponding to each extraction opening in the room calculated by a balancing procedure for supply and extraction flows and with a hypothesis of air circulation according to the distribution of the rooms, (l/s).

• qvp is the ventilation flow corresponding to each passage opening in the room calculated by a balancing procedure for supply and extraction flows and with a hypothesis of air circulation according to the distribution of the rooms, (l/s).

Also, the CTE DB HR Protection against noise addresses this issue. In Chapter 2.3 Noise and vibrations of installations it establishes that the noise and vibration levels that the installations may transmit to the protected and habitable rooms of the building will be limited. For this, restraints, or contact points, will be placed those with the construction elements, in such a way that they do not perceptibly increase the levels due to other sources of noise in the building. The document, recalling what is stipulated in Law 37/2003 on Noise, also establishes that the maximum acoustic power level of the grilles and terminal diffusers of air conditioning installations must comply with the levels of emission in adjoining rooms.

Regarding hygiene, the regulatory documents are, on one hand, the UNE 100012:2005 Standard on Hygiene of air conditioning systems and, on the other, the UNE 171330-2:2014 Standard on Indoor Air Quality. According to these documents, periodic cleaning of the entire system that comes into contact with outside air is required, that is, from the outside air grilles (outdoor air intake of heat recovery units) to the internal elements to which that outside air would be introduced (which can be grilles, diffusers, or nozzles). If the outside air is conducted to indoor air conditioning units, all equipment must be cleaned.

As you can see, there are many regulations that govern, from multiple and varied points of view, the air diffusers, those small components that, together with other elements, are part of ventilation systems.