COVID-19 has changed life as we know it, and it’s safe to say that most people are longing for a return to normalcy. As businesses reopen and adapt to new standards, they face the many challenges of creating a safe and sanitary work environment while adhering to CDC guidelines.
Some of the most important considerations are how to effectively filtrate, circulate and sanitize the air in shared and common spaces to reduce the spread of viruses. What options exist to improve air filtration and sanitization in shared office, retail, or industrial work spaces? And what new requirements might we expect commercial spaces will need to adhere to in order to ensure a safe work environment for their employees?
Senior Mechanical Engineer John Gunning recently did a Q&A with Omni Realty Group to offer his expertise on this topic.
Working within McClure’s Engineered Services division, John is responsible for the design of building mechanical systems for the commercial, educational and industrial markets. He is a licensed Professional Engineer in Pennsylvania and a LEED Green Associate. John is McClure Company’s in-house expert on the subject of ventilation and dehumidification and is frequently asked to speak at both technical and non-technical seminars regarding these subjects.
Omni Realty Group asked John a series of questions related to HVAC adjustments and standards for building operations in light of COVID-19:
Omni: Prior to COVID-19, what was considered the standard level of air filtration in most office spaces?
JG: Pre-COVID we would expect to see 1-2” thick filters with a MERV 6 to MERV 8 rating. However, some systems may use lesser rated 1” filters, MERV 4 or less, with mesh or washable media.
Omni: As people return back to physical office spaces after stay-at-home orders are lifted, what changes do you anticipate businesses making to their office spaces to be more sanitary for their workers, particularly as it relates to HVAC and air-filtration considerations?
JG: With much of the discussion of the transmission of COVID revolving around the virus in aerosol form, we can anticipate businesses thinking of their HVAC system as more than just a tool to keep the space at the correct temperature. Building codes require outside ventilation air to be introduced into the building to dilute contaminants. Over time, outside air dampers may have been closed for reduced energy usage or for service and there may not be sufficient ventilation air being provided to the building. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has also issued this position document which includes recommendations for building owners. Among the recommendations are upgrades to a minimum MERV 13 filter and use of ultraviolet (UV) lights in the airstream. Previous studies have also shown that optimal humidity range for human health and reduced infection rates of seasonal Influenza and other viruses is 40-60% relative humidity.
Omni: What are the options available for a higher standard of air-filtration in commercial spaces?
JG: Most commercial HVAC equipment will accept a 2” filter. A 2” filter can be manufactured with an efficiency rating up to MERV 13. However, there is a trade-off in both cost and in energy usage as the more efficient filter will have a higher air pressure drop. This higher pressure drop requires greater fan horsepower to move the same amount of air through the filter as compared to a lower efficiency filter.
Omni: In your opinion, what industries most need to make such improvements to air-filtration?
JG: At present, healthcare facilities and some manufacturing businesses are the industries whose filter requirements must meet or exceed the latest ASHRAE recommendations related to preventing the dissemination of airborne pathogens. Office, Retail, Education and Hospitality business are candidates for filtration upgrades as more people return to utilizing these spaces.
Omni: In addition to HVAC and air-filtration changes, what other improvements might you suggest to business owners to increase the cleanliness of their air quality?
JG: Active dehumidification is strongly recommended in order to keep the space’s relative humidity below 60 %. Limiting cooling season humidity can also reduce the risk of mold growth which can be a source of respiratory issues. On the other end of the spectrum, maintaining humidity levels above 40% is of equal importance. To that end, we expect more owners to consider the use of humidification in the heating season. Incorporating UV lights, in the supply air stream, is documented by ASHRAE as an effective method to deactivate genetic building blocks of viruses. While newer, bi-polar ionization shows potential as a technology capable of deactivating airborne viruses, it has yet to be recommended by ASHRAE. When outdoor conditions permit, increasing the use of outdoor air to dilute indoor contaminants is beneficial.
Article adapted with permission from Omni Realty Group. Read the article on Omni’s website here.