"Create a Strategic Plan Before Opening to Reduce the Risk of Airborne Virus Transmission"
Not everyone is convinced building ventilation is a significant transmitter of viruses. Improving mechanical ventilation systems in high-occupancy structures would be a critical way to reduce the risk of virus transmission.
Given the concern about airborne transmission, building managers, safety experts, and others should consider taking steps to optimize ventilation and airflow patterns indoors and limit viral spread. ASHRAE’s position that engineering controls to reduce airborne concentrations of viral particles or droplets are warranted to mitigate this risk.
Crowded and poorly ventilated buildings are most at risk for virus transmission
According to a growing number of scientists and other experts, a building’s indoor air quality is just as important as the more well-known measures in reducing transmission risk. Airborne transmission could be a significant factor in the coronavirus pandemic, especially in crowded spaces with poor ventilation.
Many droplets are quite capable of staying airborne for a significant period of time, potentially infecting those nearby. According to some sources, the virus can survive in the air for hours and on surfaces for days.
Ventilation systems in schools, nursing homes, residences and businesses may need to minimize recirculating air and upgrade filtration. Ultraviolet lights may be needed to kill viral particles floating in tiny droplets indoors.
How can airborne transmission of viruses indoors be minimized?
Automated control systems and modifications to heating, ventilation, and air-conditioning systems to help prevent the spread of viruses and other germs by purifying air, improving ventilation, and managing airflows.
If too little outdoor air enters indoors, pollutants can accumulate to levels that can pose health and comfort problems. Increase outdoor air ventialtion can reduce the concentration of contaminants such as viruses, bacteria, fungi and chemicals.
Evidence suggests that measures to change indoor airflow patterns could play a role in reducing transmission. We know that the likelihood of the coronavirus spreading through air or ventilation is probable; therefore, developing a plan to account for this risk is an essential part of proper preparation.
What are some engineering controls and interventions that may be applied to minimize the spread of the disease through the air?
1.
Increase Outdoor Air Ventilation
Disable demand-controlled ventilation (DCV).Further open minimum outdoor air dampers, as high as 100% (wheather permitting), thus eliminating recirculation.
2.
Improve Central Air Filtration
Upgrade to MERV-13 or the highest compatible with the filter rack, and seal edges of the filter to limit bypass.
Fan systems must be able to support the added pressure drop.
3.
Operate HVAC System Fans Longer
Keep systems running longer hours, if possible 24/7, to enhance the filtration and ventilation efforts. Flush building at least 2 hours before and 2 hours after occupancy
4.
Maintain Humidity between 40 - 60% RH
Humidified environments can significantly reduce the viability of viruses. Occupants are more vulnerable to viral respiratory infections with low indoor humidity
5.
UV Germicidal Irradiation & Bi-Polar Ionization
Ultraviolet Germicidal Irradiation and Bi-Polar Ionization techniques can inactivate viruses and bacteria so they are unable to replicate and potentially cause disease
6.
Air Quality Monitoring Systems
Monitoring parameters CO2, VOCs
and particulate levels with people counting devices is an excellent method of determining overcrowding and inadequate building ventilation.
Providing a healthy and sustainable building environment for all:
Carbon Dioxide Sensors
People Counting Sensors
Temperature & Humidity Sensors
Particulate Matter Transmitters (PM)
Volatile Organic Compound Sensors (VOC)
Fresh AIr Ventilation Controls Systems
Variable Air Volume Controls
Building Automation Systems
Engineering Controls
Managing Indoor Air Quality:
Filtration
Humidification
Ventilation
Ultraviolet Germicidal Irradiation (UVGI)
Bi-Polar Ionization (BPI)
Indoor Air Qaulity Monitoring