The coronavirus pandemic has drastically changed the landscape of facility maintenance and building safety. How buildings operate and the expectations of employees and customers that matriculate through them have changed forever. With the CDC confirming the potentiality of COVID-19 transmission through airborne particulates, the new normal could at some point include government mandated regulations on the filtration and quality of indoor circulated air.
For HVAC systems that have not been in usage, the American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE) has provided start-up procedure protocols with ASHRAE Standard 180-2018, Standard Practice for the Inspection and Maintenance of Commercial Building HVAC Systems. Additionally, there are other solutions that can be installed either as an add-on to an existing HVAC system or as a stand-alone system to provide facility air quality treatment.
HVAC HEPA Filters
HEPA or High Efficiency Particulate Air filters are designed to trap particulates 0.3 microns or larger including viruses, pet dander, and mold. Microns are one-millionth of a meter in size, visually we cannot see anything less than 10 microns. Bacteria ranges anywhere from 0.3 microns to 60 microns, and true HEPA filters will filter out particulates at an efficiency rate up to a 99.97% efficiency rate. These filters work by trapping the particulates in a web of fibers, and it happens either through inertial impaction, diffusion, or interception. Particulates that crash into the filter are absorbed through inertial impaction. Those that are caught while floating through the air are trapped by interception. At reduced speeds they can also be trapped by diffusion as the particulates crash into each other and are then forced through the filter.
Ultraviolet lights that are designed to work in HVAC systems are called Ultraviolet germicidal irradiation lights. The efficiency rate of these lights is dependent on their intensity level and the amount of exposure time. Several studies have shown the effectiveness of UV lights in killing mold and bacteria. In 2012 researchers at Duke University used UV lights to kill 99% of the drug resistant bacteria in their facility. In addition to the air treatment benefits these lights can also help to improve the overall cooling efficiency and reduce overall electricity costs.
There are two primary types of lights commonly used: coil sanitizing and air sanitizing. Coil sanitizing lights are positioned directly facing the coil where they can shine directly on the surface and are left on continuously. Due to the coil being used to condense moisture from the air, as air passes over it, it creates an ideal setting for the growth of mold and bacteria. These lights are the most commonly used and generally have lower installation costs.
Air sanitizing lights are installed in the existing HVAC system return air ductwork. These lights directly treat the air flowing through the system and are usually stick or u-shaped lamps. Some air sanitizing lights can be coordinated to function in coordination with the blower motor. These must be hardwired into the HVAC system, creating higher installation costs than when compared with coil lights.
Dry Hydrogen Peroxide
A new technology that is being introduced to commercial facilities is the usage of dry hydrogen peroxide for air treatment. This technology uses naturally produced oxygen and humidity to create a safe and natural level of hydrogen peroxide. All microorganisms require water to survive, and hydrogen peroxide is structurally similar to water, allowing for it to serve as an attractor. The hydrogen peroxide then attaches itself to the contaminants access points – and begins to naturally destroy them. In addition to treating the air, the hydrogen peroxide will also treat all surface areas that it comes into contact with. This process has been used in a range of commercial environments including hospitals, meat processing plants and manufacturing facilities. In addition to HVAC system add-on units, this technology is also available in portable form for individual room treatments.
We are entering a new normal in the facilities industry, where expectations on air quality have been raised. It is imperative for any air quality treatment solution that proper planning, installation, monitoring and maintenance of the system occurs. Consulting a qualified and experienced facility service companies should be the first step in navigating this new world.
Dylan O’Hana (firstname.lastname@example.org) is President and CEO of CSNA a self-performing facility services company headquartered in Houston, Texas. With more than 20 years of facility service experience, he has provided integrated facility service solutions for clients in a range of industries including healthcare, education, Oil & Gas, commercial, retail and hospitality.