Industrial ventilation: air quality and energy savings

Did you know that in office buildings the ventilation requirements are set by the Regulations for Thermal Installations in Buildings (RITE, 2007) and not by the Technical Building Code (CTE)? Furthermore, the RITE, regarding indoor air quality requirements, is based on standard UNE-EN 13779 and on the CR 1752 report from CEN. Below, we explain the different types of air that circulate through a ventilation system and how to achieve energy savings by choosing appropriate industrial ventilation for your office building.

The different types of air in your building

It is useful to differentiate between the different types of air involved in ventilation systems: outside (enters the circuit from outside), supply (enters the spaces), indoor (from the space), transfer (circulates from one space to another), exhaust (leaves the spaces), recirculated (returns to the system once exhausted), discharged (to the atmosphere), secondary (taken from a specific space and returned to it), leakage (that which passes through joints), infiltrated (from outside to inside the building), exfiltrated (leaves to the outside) and mixed air (the result of combining two or more types of air).

The outside air is classified into five types: ODA-1 (clean air that meets WHO requirements), ODA-2 (air with high particle concentration), ODA-3 (air with high contaminant gas concentration), ODA-4 (high concentration of both particles and gases) and ODA-5 (similar to ODA-4 but with very high concentrations).

The supply air can be of two types: SUP 1 (if it only contains outside air) or SUP 2 (mixed air). The indoor air quality in our buildings must be appropriate, once the emissions produced inside due to their use and occupancy have been quantified.

The indoor air is classified into four categories IDA (IDA 1 corresponds to high - clinical centers - and IDA 4 to low - not permitted). To quantify air quality, parameters such as CO2 levels, quality of infiltrated air, levels of contaminant concentrations, and rates of outside air per person and per unit area are taken into account.

Industrial ventilation: the importance of choosing an appropriate fan

If energy savings are sought, the technician must choose that industrial ventilation that ensures maximum performance. Also, to design variable flow systems: regulation through serial dampers, regulation by means of by-pass dampers, or regulation through frequency variation.

It is extremely important to adapt and condition the controlled mechanical ventilation according to occupancy needs (which will vary over time). There are two types of systems on the market, according to the positions that the fan adopts: “all or little”, whose fan has two positions (presence detector) and “proportional”, in which the fan speed depends on occupancy (which is calculated thanks to a carbon dioxide detector).

Remember that the best way to save energy in your office building is to limit thermal losses that occur within it. To do this, it is essential to install a ventilation system capable of adapting the air renewal flows according to the actual occupancy of the rooms.