Before the COVID-19 pandemic, HVAC air system design had one clear goal: delivering conditioned air as efficiently as possible. As soon as the pandemic hit, building systems diverted from efficiency, to providing cleaner and healthier spaces that reduce the spread of bacteria and viruses. Many institutions do not have the time or money for a major renovation or a total revamping of a building maintenance program.
Arguably the quickest, easiest, and most cost-effective method of making your buildings HVAC system healthier for its inhabitants is to upgrade the air filters. If your building has an HVAC system more complex than a couple of open windows, then there is a good chance that you have use for air filters. There are a handful of different air filters out there, but they all boil down to the same function: to remove dangerous particles from the air you’re breathing.
Most types of filters do this mechanically by pushing the air through a media that doesn’t allow the particles through, leaving you with cleaner, healthier air. The filter media has holes that are large enough for air to pass through but small enough that the particles get trapped.
Our good friends at the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) have derived a test method to determine how well a certain filter removes particles from the air. To categorize filters on their particle removing capabilities ASHRAE provides us with Minimum Efficiency Reporting Values or MERV rating. On a scale of 1-20 the higher the MERV rating of a filter the better it is at trapping specific types of particles. A standard commercial filtration system that we see installed in buildings is MERV 8, which effectively reduces the amount of larger particles in the air but doesn’t remove smaller, unwanted fumes, dust, and viruses. Now that building systems design is geared towards the removal of viruses, specifically the SARS-CoV-2 virus, the MERV 8 filters often seen in HVAC systems won’t cut it. For the removal of the Covid-19 virus from the air it would take either a minimum of MERV 13 or high-efficiency particulate air (HEPA) filtration system.
Image source: ISO-Aire™
A step up from replacing your filters, helping to make your building healthier, would be to install the filters with airtight gaskets around them. This would ensure that all the air moving through your ductwork passes through a filter and can’t leak around them. Leakage around filters is common even in new commercial HVAC systems because it has additional cost associated with installing. But if your building is older and there hasn’t been any recent upgrade to the air systems, then installing proper gasketing around your current filters would even help.
Now upgrading your filters and sealing them up with proper gasketing isn’t always as simple as taking the old filters out and replacing them with the highest MERV rating that you can afford. With a higher MERV rating there are HVAC system draw backs. Specifically, raising the MERV rating of your filters will raise the static pressure in the ductwork of your HVAC systems. This can cause some problems within the ductwork of your systems as well as causing more stress on your fans. Adding significant static pressure to any HVAC system might prevent your fans from being able to move the air properly through the ductwork and may require your fans in your air handlers to be upgraded as well. A great option for older HVAC systems or buildings that don’t have a routine maintenance program is to add portable HEPA filter air purifiers in the rooms where people congregate. If a quick and easy solution is what you’re looking for and you don’t feel like paying for renovation or skilled labor to install filters, then just plug an air purifier in and you’re on your way to healthy breathing. You will have to clean the air purifier filters to keep them working but at least no on needs to get on the roof or open ceiling tiles to do it.
These solutions are quick and easy, low cost and energy efficient methods of making your building a healthier space for all its inhabitants. We at F&T provide the services needed to make your building clean and comfortable while maintaining a strong backbone of energy efficiency. Please keep an eye out for our upcoming design guide “Leveraging Sustainable Technologies to Maintain Healthy Building Environments” for a full view of options available to help buildings and owners breathe easier.
Fitzemeyer & Tocci is dedicated to designing both health and energy-efficient building systems.
Fitzemeyer & Tocci Staff