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Indoor Air Cleaning Technologies for Your Facility

Tuesday, May 19, 2020

Cost-Effective Solutions that Reduce the Risk of Infectious Aerosol Pathogen Spread

Traditionally there were two ways of reducing the risk of pathogen spread using your building’s existing heating and cooling system. Increase the amount of outdoor air changes or increase the filter efficiency. 

An increase in the amount of outdoor air changes can be used to dilute the pathogen’s concentration in the building thus reducing the risk of spread. Unfortunately, most systems lack the heating and cooling capacity to take on the additional amounts of outside air. This results in a loss of occupant comfort. 

An increased filter efficiency to a level that would capture pathogens and reduce the risk of spread would result in a significant reduction in airflow. The loss of airflow would decrease the system’s ability to heat and cool the space. In most cases, these two strategies require a costly upgrade to the heating and cooling system to maintain the occupants' comfort.

There are two alternative more cost-effective ways to reduce the risk of infectious aerosol pathogen spread in buildings using the existing heating and cooling systems. One being ultraviolet light and the other being bi-polar ionization.

Ultraviolet light has a long track record of disinfecting and deactivating viruses. These lights can be installed in air handling units and bathe the cooling coils in ultraviolet light.  Installing the lights in this location will prevent things from growing on the coil and in the drain pan. Care must be taken to install the proper intensity and type of ultraviolet light. Ultraviolet lights should produce light at the UVC wavelength for the best results. While UV lights installed in an air handling unit can be the lowest first cost option of the two options; the lifetime costs should be taken into consideration. While the UV lamps will continue to emit light for a long time, they lose intensity quickly and will need to be replaced on a regular basis to be fully effective. There are a couple of things to keep in mind when making a decision on UV lights. UV lamps can work on pathogens that find their way into the air handling unit, so pathogens that remain in the space will not be effected by the UV light. Also, UVC light is dangerous to human skin. Much more so than the UVA and UVB light we encounter from the sun. The installation of these lamps should have a switch located nearby to allow future service work to be performed with the lights off.

Bi-polar ionization has been around for a long time but more recent advances in the technology have made it more effective and safer to use. Bi-polar ionization systems generate both positive and negative ions in the ducts of a building where they are distributed to the occupied space.

These ions perform three tasks while in the occupied space.

1. Kill mold spores and bacteria and neutralize viruses.

2. Reduce particles in the air by causing the particles in the air to stick together. These larger “clumps” of particles are easier to move back to the air handling unit and their larger size makes them easier to filter out. Using an ionization system allows less efficient filters to act more like high efficient filters cleaning the air better.

3. Break down odor-causing particles and oxidize them into gases like oxygen, nitrogen, carbon dioxide and water vapor.  This process will eliminate the odor from the oxidized particles. 

Ions are a safe and naturally occurring in our environment. Bi-polar ionization systems simply increase the concentration of the ions.  Care should be taken when selecting an ionization system. Many of the systems on the market produce ozone while generating ions, but not all of them do. UL has a testing procedure for this and you will want to make sure the ionization system is UL-867 Section 37.2.1 certified. 

Finally, the life cycle cost of this system should be taken into consideration. While an ionization system will cost more upfront than an ultraviolet light system; there be very little maintenance costs and the system will ultimately cost less than an ultraviolet light system.

Talk to an Ahern professional today to see how ultraviolet lighting systems or bi-polar ionization systems can be used to reduce the risk of infectious aerosol pathogen spread.

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