Commercial HVAC Guidelines for Air Purification – An Overview

Commercial HVAC Guidelines for Air Purification – An Overview

Filtration and ventilation have always been important considerations for any commercial premises. As facilities managers or administrators, you look for solutions that maintain the indoor air quality at optimum levels to ensure the comfort and safety of your building occupants, guests, and visitors. The COVID-19 pandemic has further heightened the need for high-efficiency HVAC systems with air purifier capabilities that enhance indoor air quality and prevent the spread of deadly viruses that travel through the internal ducting and venting systems. In fact, most Canadian provinces, including Ontario, have issued HVAC systems guidelines to reduce the transmission risk of viruses through a multi-layered approach. While physical distancing, screening, mask-wearing, and hand hygiene are all critical measures within these directives, the provincial guidelines also stress improved air distribution, including removing and diluting aerosols, increasing air-exchange rates, and more.

Improving the air quality within your commercial premises in an energy efficient manner involves greater air changes, free cooling with external ambient temperatures using economizers, proper humidification to avoid excessive dryness, and dehumidification to prevent mold growth.

With the increased focus on air filtering, air cleaning and efficient heating and cooling systems, it is time to re-evaluate your commercial HVAC systems and invest in the necessary upgrades for your premises. The HVAC professionals at TRI-AIR Systems offer insights into the future of commercial HVAC systems and air purifier mechanisms during and beyond the COVID-19 pandemic.

Air Purifiers and Air Filtering

Stale air circulating within your premises can be the biggest culprit in spreading pollutants, allergens, and disease-spreading viruses. Improving the quality of indoor air is achievable through:
Air Filtration: Reduce dust, mites, pollen, and toxins by installing air filters in your HVAC systems.
Air Purification: Sanitizing the air by neutralizing airborne toxins, including pathogens, bacteria, viral or fungal matter, gases, and more.

While air filtration systems trap the airborne particles, air purifiers or air cleaners kill or transform the airborne toxins into harmless particles. Investing in the best air purifiers and air cleaners will help you achieve purer, richer, and more oxygenated and breathable air for your commercial premises.

The two main types of air filters are:
High-Efficiency Particulate Air (HEPA) can filter out 99.97 percent of particles as small as the diameter of a single human hair. HEPA filters rate 17 or higher in terms of filtration efficiency.
Minimum Efficiency Reporting Values (MERV) filters that can provide varying levels of filtration, based on their efficiency rating that ranges from 1 (lowest) to 16 (highest).

For air purification, there is no better option than direct sunlight. The ultraviolet (UV) rays act as natural purifying agents to remove harmful elements from the air. However, in commercial spaces where leaving doors and windows open is not an option, the next best solution is UV air purifiers that mimic the sun’s purification properties using ultraviolet light waves. Central purification systems ride on the commercial HVAC systems, treating the air intake in the AC coil or the air ducts.

Ventilation and Air Flow

There is not yet enough data or research to suggest the exact risk of viruses spreading through ventilation systems. However, there is evidence that airflow can be an important factor in the transmission of diseases, such as COVID-19, influenza, or SARS in an indoor environment. While the best way to enhance the airflow is by opening the windows and doors, this may not always be feasible in Canadian regions that experience extreme temperatures. In order to prevent the stale air from recirculating within your premises, you need to maximize the outdoor air ratio settings of your HVAC system. This is achievable by:
● Increasing air filtration to as high as possible, without any significant reduction in the design airflow.
● Using appropriately sized filters that are within their recommended service life.
● Maintaining regular checks on the filter housing and racks, which ensures proper filter fit and redirects the air through the filter instead of around it.

Efficient ventilation mitigation strategies can help reduce virus particle concentration and increase the safety of the building occupants significantly. Here are some key aspects to consider:
● Direct the air upwards instead of at the head level. This will help avoid direct airflow around people’s breathing zones and, in turn, reduce the dispersion of respiratory droplets from person to person.
● During mild weather, open the outdoor air damper beyond the minimum settings to prevent HVAC air recirculation as much as possible. As long as the weather is not too hot or too cold, this will not hamper the humidity or thermal comfort.
● Rebalance or adjust the HVAC settings to increase the total airflow to occupied spaces as much as possible.
● Set the HVAC system fan to “On” instead of “Auto” to improve airflow even when the heating or air conditioning auto-shuts off due to the thermostat.
● Ensure that the exhaust ventilation systems, especially in areas like office kitchens, cafeterias, and bathrooms, are operating at total capacity even when the building is not at full occupancy.
● Evaluate and reposition the exhaust grills, supply louvres, and damper settings to maintain optimum airflow.
● Keep the areas near HVAC inlets and outlets clear as far as possible. Try to arrange staff or visitor seating away from areas with high airflow.
● Ensure regular maintenance of your HVAC system and use the highest-efficiency compatible filters

Indoor Air Quality—The Role of Air Purifiers, Air Filtration Systems and Air Cleaners

An increasing number of studies on the highly transmissible SARS-CoV-2 virus suggest that fine viral particles linger in the air long after an infected person coughs, talks, or sneezes. This means, areas such as lobbies, cafeterias, waiting rooms, and other commercial or retail spaces frequently occupied by a significant number of people are high-risk areas. In these spaces, there is a greater likelihood of multiple people catching an infection within a short span of exposure to the airborne viruses.

In addition to UV air purifiers and air cleaners, it is wise to invest in portable HEPA filtration systems to improve indoor air quality. HEPA filters not only trap disease-causing virus particles but they also filter out dust mites, spores, pet dander, pollen, and other harmful elements or toxins that trigger allergies or asthma. Although HEPA filtration can enhance the air cleaning capabilities of your HVAC systems, remember that the reduction of indoor particle concentrations depends on a combination of multiple factors, including:
● Particle removal efficiency of the filter
● Location of the filters
● Size of the particles
● Rate of airflow through the filter

Air Change Rates and Outdoor Air Circulation

Air change rate is defined as the “volume of air supplied to and removed from a space, via mechanical systems or through the building enclosure, per unit of time divided by the volume of the space.” Besides the Canadian Standards Association (CSA), several other associations provide air change rate standards for HVAC systems in different building environments based on the potential for airborne infection risks. Simply put, air change rate or outdoor air changes per hour (ACH) is the rate at which the air in a space is completely recycled. The higher the ACH, the lower the risk of a person inhaling virus particles. Increasing the ACH means bringing fresh air from outside or eliminating the contaminants from the inside. Your commercial premises with centralized HVAC systems will benefit from high-quality air purifiers, as well as mechanical filters of MERV 13 or higher.

CO2 Levels and Ventilation in Commercial Buildings

Indoor CO2 levels are often a good indicator of Indoor Air Quality (IAQ) and ventilation in commercial buildings. High levels of time-averaged indoor CO2 levels can help you identify the spaces with poor ventilation rates and prioritize your ventilation mitigation efforts appropriately. As per ASHRAE, indoor CO2 levels should not exceed the local outdoor concentration by more than 650 ppm. Using CO2 monitors with sensors will enable your HVAC system to automatically modulate the volume of outside air (OSA) brought indoors and maintain the CO2 levels at the desired concentration. Also known as Demand Controlled Ventilation (DCV), these systems are beneficial in areas, such as gyms, cafeterias, or conference rooms where ventilation rates may fluctuate significantly based on the occupancy levels.

Maintenance and Timely Repairs for Commercial HVAC Units

The American National Standards Institute (ANSI), ASHRAE, and Air Conditioning Contractors of America (ACCA) jointly define the standards for HVAC inspection and maintenance. These standards aim to preserve your system’s ability to achieve acceptable energy efficiency, thermal comfort, and indoor air quality in commercial buildings.

Whether it is the air filters, humidifiers, the fan belt and alignment, the fresh air economizer, the heat exchangers, fuel lines and power sources, or any other component of the HVAC system, routine maintenance and timely repairs are an integral part of safety and comfort for your workplace. While comprehensive maintenance is critical in ensuring the reliability and efficiency of your commercial HVAC systems, other benefits include:
● Decreased heating and cooling bills and an overall reduction in energy costs
● Improved heating, cooling, and air quality
● Lesser chances of breakdowns or malfunctions that lead to expensive repairs
● Extended lifespan of the HVAC systems

Heating and cooling systems are complex, and any changes you make may have unintended effects. Hence, it is always advisable to hire trusted HVAC professionals who can verify the relevant parameters, carry out appropriate maintenance procedures, and ensure that your commercial HVAC systems run smoothly and efficiently.

Even the Best Air Purifier and Air Filtering Practices Aren’t Enough, But They Help…a LOT!

As we go through the various stages of economic recovery and employees, clients and visitors start going back into workplaces. Your commercial spaces will need to cater to the increased occupancy levels without compromising on safety. However, there is a growing consensus among the scientific community that the SARS-CoV-2 virus primarily spreads through the air. Putting a lot of people in poorly ventilated spaces could elevate the risk of transmission and jeopardize the health of your building occupants.

As facilities managers or administrators, you are responsible for the health and safety of the staff, guests, or clients who visit and occupy your commercial premises. This means adhering to the public health and workplace safety guidelines, as well as enhancing the filtration and ventilation measures within your premises.

Pro Tip: Investing in the best air purifiers and air filters or following all ventilation mitigation practices may not entirely eliminate the risk of air contamination. However, they will significantly improve the thermal comfort, energy efficiency, and indoor air quality of your premises.

At TRI-AIR Systems, we have over 40 years of experience in HVAC systems installation and maintenance and understand the role of air purifiers, air cleaners, and heating and cooling systems in maintaining safe and comfortable workplaces. Check out our guide to better air quality and let our experts help you optimize your HVAC systems for air purification, air cleaning, ventilation, energy efficiency, and more.

Call TRI-AIR Systems, 905-470-2424 or contact us online for reliable 24-hour commercial and industrial HVAC needs.

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