According to the latest research by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), ventilation and filtration provided by heating, ventilating, and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures.
Prism has been working closely with St. George’s School to conduct a review of their HVAC systems with respect to its existing functionality to mitigate COVID-19 transmission based on established engineering practices and the most up to date ASHRAE guidelines.
The facilities team at St. George’s School engaged Prism Engineering to leverage their expertise in mechanical engineering and provide site-specific recommendations based on the newly developed ASHRAE guidelines. The objective is to mitigate the risk of COVID-19 transmission within the facilities.
HVAC operations assessments, controls reviews and airflow measurements were conducted to verify the air change rates for each classroom within the Junior and Senior school campuses. A compilation of area-specific ratings with respect to their current effectiveness at mitigating Covid 19 transmission was developed and presented along with a list of recommendations.
Upon initial review, there were several areas within the school campuses that could benefit from immediate improvements and upgrades. Prism worked with the building operators to promptly address these vulnerabilities. Specific actions undertaken included:
- Addition of local air purifiers, UV and HEPA filters
- Upgrade of all filtration in air handling systems to MERV 13
- Investigation and resolution of the HVAC system and control consistency
- Upgrades of Direct Digital Controls (DDC):
- Implementation of ventilation air flush for before and after occupancy
- Confirmation of outdoor air damper position
- Updates and confirmation of equipment schedule
- Validation of the DDC modifications
- Optimization of local air purifying equipment locations
- Based on the actions taken to date, a significant improvement in the controls, filtration and air changes per hour has been obtained.
In areas where immediate action was not practical, occupant loading was reduced, and students were relocated to spaces with lower risk of transmission.