As we discussed in our previous introductory article on the basics of HVAC, these systems consider the management of environmental factors between human comfort and machine operation. However, HVAC is just one aspect of a building’s wider ventilation plan. To put this into perspective, MEP as a broader discipline places great importance on ventilation strategies that aren’t necessarily encompassed in the design of HVAC systems. This includes stairwells, lifts, corridors, electrical systems, room sizes, human occupancy limits, geography and so on.
Therefore, ventilation is one of the most critical components in building design from an MEP perspective. Ventilation, in its most basic definition, refers to the removal of ‘stale’ air from a building and replacing it with ‘fresh’ air. Ventilation technology not only provides fresh air for us to breathe but is also important in moderating temperature and humidity levels, replenishing clean oxygen and reducing moisture from structures. Considering the recent health crisis, this is an absolutely crucial function.
The difference between mechanical and natural ventilation
There are two essential subsets of ventilation: mechanical ventilation and natural ventilation. When we talk about mechanical ventilation systems, we refer to an HVAC-oriented approach that relies on machines such as fans, ducts, pumps and other technology that ‘forces’ the circulation of air throughout a building and generates movement. This improves everything from general comfort to enhanced health and safety.
On the other hand, natural ventilation works by utilising the natural pressure differences within sections of buildings, or generally, the differences in the pressure found inside versus outside the structure. The most common “wind-driven” approach works by drawing natural air from the high-pressure side of a building and ventilating it out through its low-pressure side. Though natural ventilation is generally chosen as a cost and time-effective solution in building design, it is often difficult to accomplish due to the precise physical and geographical factors.
The hybrid approach to better indoor ventilation
Current developments in MEP have found that a balanced approach (i.e., combining natural, mechanical and other technological ventilation elements) can be an excellent solution for both comfort, health, safety and cost reduction. Air filtration units, for example, are just one example of this hybrid application. What’s more, these solutions are now more relevant than ever given the current COVID-19 pandemic and its relationship with the proper ventilation of occupied spaces. For example, a recent study found that the installation of air purification units in classrooms reduced the concentration of infectious particles by one-third compared to the control, which used only a traditional HVAC system.
Air purification units may be deployed in buildings with preexisting ventilation systems that may not already provide optimal filtration and ventilation of contaminants. When utilised as auxiliary technology, in both mechanical and natural ventilation systems, such products ensure occupants can breathe the cleanest, safest air in their homes, offices and classrooms. Strategic installation of these units will be something your MEP engineer will be able to advise on – so consider incorporating them as a part of a comprehensive ventilation strategy.