HVAC Solutions to Reduce COVID-19 Exposure
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Although most of New York City’s towering commercial buildings remain unoccupied as the city continues to be on pause, it’s time to talk about tenants returning to the workplace. People are likely to be anxious about going back, but facility managers can play an important role in helping tenants feel more comfortable about returning to work by taking action to show that they are doing everything within their control to make their buildings safer.
Stephanie Taylor, MD, M Arch – a Harvard Medical School ASHRAE Distinguished Lecturer – recently gave a presentation1, in which she explained the nature of the COVID-19 virus. It can be alive and contagious in the air for four hours. It lives on cardboard for seven days. It can be aerosolized by speech – which means that it can be transmitted simply by talking, without having to cough or sneeze.
For facility managers, improving the HVAC systems in their buildings is key to both preparing buildings for re-occupancy as well as keeping buildings and people safe once tenants return. There are a number of effective solutions. What facility managers need to keep in mind is that even a cleanroom environment will not guarantee a COVID-19-free space. So, while the recommendations below will not prevent COVID-19 exposure, they are effective in helping to reduce exposure.
In the same way that New York started with 25 percent of employees working from home and eventually reclassified nearly all non-essential employees as work-from-home employees, it is likely that the city will phase the return back to work as well. As tenants return to buildings, they’ll need to know that measures have been taken to create a clean and safe environment. Signage and regular communication describing what has been done will be important.
Plumbing
Plumbing system maintenance may not be top of mind right now, but there are a couple of maintenance procedures that are important to take. Confirm that all traps in floor drains are primed to prevent odors and sewage gases from entering the spaces and turn on faucets every 2-3 days to prevent stagnant water.
Dilution Ventilation (Increasing Outdoor Air)
Increasing outdoor air is one step that can be taken to exhaust the airborne virus out of buildings and bring in fresh outdoor air. If companies limit the number of people physically in their office, increasing the amount of outside air would be possible because the HVAC load is reduced. In addition, seasonal outdoor air temperatures may allow outside air to be supplied, with 100-percent outdoor air being preferable.
Ultraviolet Germicidal Radiation (UVGI)
Ultraviolet lighting methods can be integrated into mechanical systems to capture and eliminate viral particles. An expert should design and install any UV lighting because these systems can be dangerous to facilities personnel (as well as ineffective in getting rid of COVID-19) if not installed correctly.
Photocatalytic Oxidation (PCO)
PCO is an air-cleaning technology. It can be used in any building type and in almost any air handling system. PCO improves indoor air quality by reducing the bacteria, viruses and VOCs in the air that pass through the system. It breaks them down by modifying the chemical makeup of the particles in the air. The chemical modification to clean the air takes place in the PCO panel within the duct or air handling system. This can be more effective when combining PCO with UV protection, as long as all of the recirculated air is treated.
Ionization
Ionization technology is a process that generates positive and negative ions. The ions are used as a catalyst to break down bacteria, viruses, and VOCs. Many of the ionizers on the market generate ozone that is a known molecule to damage the health of humans. Ozone generators should not be used in any commercial buildings. Non-ozone ionizers create an ion percentage higher than typically found naturally and, therefore, the long term adverse health impacts are a concern. Some studies show how the ions that help to break down the bacteria, viruses, and VOCs in the occupied breathing zone will also break down our bodily tissue. We would only recommend this type of technology be used during the hours a building is not occupied.
Filtration (MERV)
While MERV filters improve indoor air quality, they alone are not effective in removing viruses from the air. Making any modifications to HVAC systems, such as adding MERV filters, can create larger pressure drops in the system, which can impact the system operation.
Humidification
Higher humidity in a space causes viruses to latch to water molecules and “sink” to the ground, making them less airborne, which reduces airborne transmission of the virus. The building envelope needs to be reviewed prior to installing any type of humidification.
Electrostatic Precipitation Cleaning (EPC)
EPC is a cleaning method that sprays a mist that adheres to surfaces and objects. It is more effective than traditional cleaning because it does not kick up resting particles and redistribute them onto other surfaces. EPC is recommended if there is an occurrence of COVID-19 in a building but is not necessary if a building has been unoccupied for weeks.
There is no one solution for all buildings, but these suggestions above can and should be considered by facility managers in collaboration with an MEP engineer. What is true for every facility manager in every building in New York City is that steps should be taken to contribute to making buildings safer to save lives.
By David Bonifacic, CEO, WB Engineers+Consultants; Raymond Doyle, Managing Principal & Life Science Practice Leader, WB Engineers+Consultants; Desmond Greene, Managing Principal & Asset Strategy & Repositioning Practice Leader, WB Engineers+Consultants
1Taylor, Stephanie, MD, M Arch. “Indoor Air Hydration: The game changer to staying healthy during COVID-19 and beyond!” ASHRAE. April 15, 2020. Webinar.
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