Page 104 - Security Today, September/October 2021
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Air Quality
By Kelly Kleinfelder
9 Ways to Reduce Contaminants
Facility managers should consider practical steps first
To protect students and employees from the SARS- CoV-2 virus that causes COVID-19, air quality should be a top concern for school and college administrators. As we have learned more about how COVID-19 spreads, it has become clear that the vast majority of cases occur through airborne transmission—and improving the ven- tilation in campus buildings should be part of a layered approach to health and safety that includes multiple mitigation strategies.
Ventilation system upgrades can increase the flow of clean air and reduce the presence of contaminants inside buildings. Here are some practical steps that facilities managers and other leaders can take right away to improve campus indoor air quality.
Below are four simple, low-cost strategies for increasing the air flow in buildings, as well as five additional suggestions for improving the existing ventilation systems in schools and colleges to prevent the spread of SARS-CoV-2 and other contaminants. These suggestions draw on guidance from the American Society of Heating, Refrigera- tion and Air-Conditioning Engineers (ASHRAE) and the Centers for Disease Control and Prevention (CDC).
Simple Strategies
Introduce more outdoor air into buildings. If you can, open out- door air dampers beyond their minimum settings to reduce the amount of air that is recirculated from HVAC systems. When weath- er conditions allow for this, open windows and doors to increase the flow of air from outside. Even a slightly open window can introduce beneficial outdoor air.
Increase air flow and circulation. Use portable fans wherever pos- sible to circulate clean air and direct potentially contaminated air outside. Avoid placing fans in a way that could cause contaminated air to flow directly from one person to another. According to the CDC, one useful strategy is to use a window fan to direct room air outside. This will help draw outdoor air into the room through other open windows and doors without generating strong indoor air cur- rents. Similar results are achieved in larger facilities using gable fans and roof ventilators, the CDC says.
Make sure ventilation and air filtration systems are working properly.
Check to ensure that all building ventilation systems are operating correctly and provide acceptable air quality for the occupancy in each space. Make sure air filters are properly sized. Inspect filter housing and racks to make sure filters fit correctly and to minimize the amount of air flowing around, instead of through, the filter. Make sure restroom exhaust fans are functioning properly and operating at full capacity when the building is occupied. Inspect and maintain exhaust ventilation systems in areas such as kitchens, and consider operating these systems any time the building is occupied.
Adjust HVAC system settings to maximize air flow. Adjust the set- tings on HVAC systems to increase total air flow to occupied spaces wherever possible. Turn off demand-controlled ventilation (DCV)
controls that reduce air supply based on temperature during hours when a building is occupied.
In buildings where the HVAC fan operation can be controlled by a thermostat, set the fan to the “on” position instead of “auto,” which will operate the fan continuously—even when heating or air condi- tioning isn’t required.
More Complex Solutions
Upgrade HVAC systems to MERV 13 or better. Many schools and colleges have decades-old HVAC systems that will do little to prevent the spread of airborne viruses within buildings. An air filtration sys- tem’s ability to remove particulates from the air is rated on a number system called Minimum Efficiency Reporting Values, or MERVs. This rating system is helpful in comparing the performance of different filters; the higher the MERV rating, the better a filter is at trapping airborne particles.
Both ASHRAE and the EPA recommend using the highest-effi- ciency air filters you can afford to combat the spread of COVID-19 in buildings, with a minimum efficiency target of MERV 13. According to the EPA, “Filters with MERV-13 or higher ratings can trap smaller particles, including viruses.”
The New York City Public School System has spent millions of dol- lars to upgrade the HVAC systems within its schools from MERV 8 to MERV 13 filtration. Upgrading the air filtration within HVAC sys- tems to a MERV 13 rating or better gives schools and colleges the best chance at capturing airborne SARS-CoV-2 particles and removing them from the air inside buildings.
Use HEPA filtration systems to help clean the air.
HEPA stands for “high-efficiency particulate air” filtration, and these filters are highly effective at pulling impurities from the air and holding onto them so they can not recirculate. HEPA filters techni- cally aren’t MERV rated, as the MERV scale stops at 16. However, if the MERV scale continued beyond 16, HEPA filters would be rated between MERV 17 and MERV 20. HEPA filters are considered 99.97% effective at filtering particulates as small as 0.3 microns.
HEPA filters can be used inside many HVAC systems, and portable HEPA filtration systems are also available to clean the air inside indi- vidual classrooms and other indoor spaces.
Consider using UVGI technology to supplement air filtration. Hospitals and other sterile environments have been using technolo- gies such as ultraviolet germicidal irradiation (UVGI) for years to remove harmful contaminants on surfaces and in the air—and this technique is proving to be effective in mitigating the spread of COVID-19 as well.
UVGI involves the use of ultraviolet-C (UVC) light rays to kill the SARS-CoV-2 virus and other contaminants. Direct exposure to UVC radiation inactivates the virus; however, schools and colleges must use UVC lamps with caution, as UVC exposure to human skin or eyes can cause injuries. Using an air purifier or filtration system that contains

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