PROTECTING YOUR MOST VALUABLE ASSET
PROTECTING EMPLOYEE HEALTH
Mark Graybill, P.E., HB McClure Engineer
Much of the population is ready for a return to some normality after months of not working or working from home due to COVID-19, but it does not mean the virus is gone. What can we do to reduce the potential transmission of COVID-19 and future flulike viruses in our workplaces? As our offices begin to open in Pennsylvania, we need to minimize the risk of transmission to our employees and customers. As a mechanical engineer specializing in HVAC, I view this challenge in the same way I approach other industrial indoor air quality challenges. Try to capture as much of the contaminant at the source, then filter and dilute the rest. Here are other steps we have been helping clients take to reduce the transmission of viruses in the workplace.
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CONTENTS BASICS............................................................................ 3 HVAC SOLUTIONS....................................................... 5 PLUMBING SOLUTIONS............................................. 7 ELECTRICAL SOLUTIONS........................................... 7
“Transmission of SARS-CoV-2 through the air is
sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures.”
— ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers
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THE BASICS MASKS: While inconvenient, masks are an important component of source capture while on heightened alert. Even cloth masks are effective at capturing respiratory droplets which carry the smaller COVID-19 virus. Where masks are not practical and distancing is not an option, consider adding physical barriers such as plexiglass. INCREASE OUTDOOR AIR FLOW TO YOUR BUILDING: Outdoor air is likely to have much lower concentrations of COVID-19 and other contaminants than indoor air. Ensuring outdoor air intakes are open and investigating methods of increasing outdoor air will allow for more dilution and cleaner air. I recommend also temporarily disabling energy-saving outdoor air control strategies like CO2 demand-controlled ventilation. UV LIGHTS: Most UV systems are designed for radiating coils within HVAC units, not for sterilizing fast-moving air. Some systems with higher UV concentrations are available but are primarily intended for the healthcare industry.
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BIPOLAR IONIZATION: This is the best upcoming technology for air treatment. The positively and negatively charged ions it creates breaks down viruses, bacteria, and gases in the ductwork and throughout the building. Additionally, the charged ions attract smaller particulates together, enhancing the effectiveness of centralized filtration systems. This technology is better than photocatalytic oxidation systems that use small UV lights and a metallic catalyst that often inadvertently create ozone and complaints of a metallic taste. FANS & FILTERS: Most of these steps require the HVAC system fans to run constantly during occupied hours. This is an important and easy setting change on most thermostats that is often overlooked. Increasing the MERV rating (efficiency) of filters is an important consideration. Most standard pleated filters are MERV 8, allowing virus particles to pass right through. Replacement filters are available in the same dimensions up to MERV 13 which can capture the virus-carrying droplet nuclei. Paired with bipolar ionization, the filters are even more effective. By working with a trusted company like HB McClure, you can keep a clean atmosphere and minimize the risk of spreading COVID-19 and other viruses among your employees and customers.
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HVAC SOLUTIONS INCREASE FILTRATION RATINGS OF AIR FILTERS Option 1: Replace filters in existing units with new ones rated up to
MERV 13 (standard pleated filters are MERV 8, spun fiberglass filters are only MERV 4 or lower). This is the best filtration available for
most conventional filter racks. The added pressure drop should be evaluated on systems with marginal fan performance.
Option 2: Add HEPA filtration (better than MERV 13) for part of the
return air with a dedicated unit and fan. This is the best type of filter
available. This adds no additional pressure drop, but it does not filter all of the return air.
ADJUST FAN SETTINGS Turn on HVAC fans continuously during occupied hours to bring in outdoor air and to run indoor recirculated air through the filters. Dilution and filtration are some of the best things we can do to improve indoor air quality.
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BIPOLAR IONIZATION Bipolar Ionization creates positively and negatively charged ions that breakdown bacteria, viruses and other contaminants in the air. It produces no ozone Unlike UV technology, the ions continue through the ductwork and interact with the contaminants in the space instead of just what is in the unit.
INCREASE OUTDOOR AIR This allows for dilution of contaminants Temporarily disable CO2 demand-controlled ventilation or decrease the CO2 PPM setpoints. Right now, increased dilution of potential contaminants is more pressing than energy savings. Add Energy Recovery Ventilators to increase the outdoor air without needing to increase air conditioning tonnage. Consider adding dehumidification and humidification, as increasing outdoor air can require these changes. Humidification reduces the life of bacteria and viruses while dehumidification reduces mold growth.
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PLUMBING SOLUTIONS REDUCE TOUCHING OF SHARED SURFACES Touchless lavatory faucets Automatic flush valves for toilets and urinals Additional handwashing locations
ELECTRICAL SOLUTIONS ELIMINATE LIGHT SWITCHES Motion sensor lighting
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“It is very important to understand that the system recommendations we outline need to be administered through an engineered solution or it could have a detrimental effect on your building’s indoor climate. For example, to increase outside air intake to your building has a direct impact on the ability of your existing equipment to handle the added load, which could lead to CARL FEASER
VP of Commercial Construction, HB McClure
uncomfortable conditions and high energy costs. H.B. McClure engineers can help you make wise and informed decisions on what is best for your situation”
“COVID-19 has added new safety challenges for all of us. Resources and equipment have dramatically improved to provide cleaner air and reduce virus spread, including COVID-19. It’s a collaborative effort between HB McClure and our customers to help preserve their employees’ health and well-being. There is still much to be done in terms of education for business/building owners. I’m proud to see our HB McClure experts leading in this manner and NICK HENCH
creating safer work environments across Central PA.”
Safety Coordinator, HB McClure
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Call us today for a free, expert assessment of your building!
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EngineeringSolutions@hbmcclure.com