1. Increase outdoor air ventilation, using caution in highly polluted areas.

Assessments conducted prior to the opening of schools in September 2020 and again during mid-winter break showed one hundred percent of district schools increase outdoor air ventilation by use of air handler units, roof top units, unit ventilators, or open windows. List of schools may be found in the appendix.

2. When weather conditions allow, increase fresh outdoor air by opening windows and doors. Do not open windows and doors if doing so poses a safety or health risk (e.g., risk of falling, triggering asthma symptoms) to occupants in the building.

While eighty-four percent (83.5%) of our buildings open doors and windows when weather conditions allow, fresh air intake is supplied at all District facilities. Five of the district’s facilities, found in the Appendix, were constructed with curtain wall windows that do not open. All of these buildings now have functioning air conditioning as well as operable ventilation systems. A number of schools were built with windows in need of repair however, these buildings were designed with central mechanical systems to circulate outside air without use of windows. If staff members at these schools, listed in the Appendix, would like a fan for additional circulation, they may contact the COVID-19 reporting line anonymously at (313)578-7018 or by email: info.reopen@detroit12.org.   

3. Use fans to increase the effectiveness of open windows. To safely achieve this, fan placement is important and will vary based on room configuration. Avoid placing fans in a way that could potentially cause contaminated air to flow directly from one person over another. One helpful strategy is to use a window fan, placed safely and securely in a window, to exhaust room air to the outdoors. This will help draw fresh air into room via other open windows and doors without generating strong room air currents.

Most of the older constructed buildings were designed to use a combination of windows and corridors to supplement the natural fresh air intake of ventilation systems. Fans will be provided for staff upon request made with the building engineer. 

4. Decrease occupancy in areas where outdoor ventilation cannot be increased.

Facility team members continuously work with principals to assign spaces based on daily operations. The district completed baseline ventilation assessments prior to opening schools at the beginning of the year to identify problem areas. Areas will poor ventilation were taken offline and building engineers collaborated with principals to determine alternative placement. Ventilation assessments are a continuous process; should problems arise in the future, building engineers will continue to work with principals to identify use of other classrooms.   

Any rooms without outside ventilation will not be used until after repairs are made. Our current indoor air quality assessment and analysis report will report problem spaces on a dashboard that will be placed on the District’s website. 

5. Ensure ventilation systems operate properly and provide acceptable indoor air quality for the current occupancy level for each space.

All district buildings were assessed in the summer of 2020 by facilities vendors.  Results showed 34 schools needed immediate repairs for optimal functioning, see Appendix for list of schools.  Repairs were completed and the units were reassessed during mid-winter break in 2021. As an additional measure, an independent environmental health company is completing carbon dioxide testing in all district schools. CO2 assessments can ensure acceptable levels of ventilation are provided.  If assessment results demonstrate the need for additional ventilation repairs, the identified space will be removed from use until repairs are made. A dashboard listing assessments results will be placed on the district’s website upon project completion.   

6. Increase airflow to occupied spaces when possible.

Assessments conducted prior to the opening of schools in September 2020 and again during mid-winter break showed one hundred percent of district schools increase outdoor air ventilation by use of air handler units, roof top units, unit ventilators, or open windows when outside weather conditions permit.

7. Turn off any demand-controlled ventilation (DCV) controls that reduce air supply based on occupancy or temperature during occupied hours. In homes and buildings where the HVAC fan operation can be controlled at the thermostat, set the fan to the “on” position instead of “auto,” which will operate the fan continuously, even when heating or air-conditioning is not required.

Numerous facilities have unit control systems in need of repair and upgrade. Building engineers manually control mechanical units in these buildings to prevent overheating during summer months and pipe and system freezing during the winter season.  While manual controls reduce efficiency and effective use of each building engineer’s time, this work maintains adequate ventilation levels. The district’s broader plan involves use of CARES Act funding to upgrade broken controls and implement automatic controls that can be monitored onsite and remotely.

 8. Open outdoor air dampers beyond minimum settings to reduce or eliminate HVAC air recirculation. In mild weather, this will not affect thermal comfort or humidity. However, this may be difficult to do in cold, hot, or humid weather.

Automated air damper controls are in need of repair limiting the maximum opening of the units in 37% of schools. In such cases, the ventilation system is manually controlled and operated by engineers using a combination of mechanical air passage systems, windows, and fans for fresh air intake. 

A more detailed assessment is scheduled for spring 2021 after which recommendations for improvement will be produced by independent HVAC consultants. Upon receipt of external air quality assessments, identified units will be repairs and upgraded for digital operations. 

 9. Improve central air filtration: 

A. Increase air filtration to as high as possible without significantly reducing design airflow. 

Approximately 88% of schools can increase air filtration through use of higher rated MERV filters without affecting design.  The remaining 12% of schools use filter ratings designed for existing units.  

B. Inspect filter housing and racks to ensure appropriate filter fit and check for ways to minimize filter bypass. 

All filter housing and racks have been inspected at all schools and 93 units were repaired.  

C. Check filters to ensure they are within their service life and appropriately installed. 

Filter replacement frequency increased at all of District facilities.  At the time of the assessment, 10% of filter replacements were in progress as scheduled.  

 10. Ensure restroom exhaust fans are functional and operating at full capacity when the building is occupied. 

The district conducted building assessments based on CDC guidance during mid-winter break of 2021. The results showed approximately 68% of restroom exhaust fans work per design, see list of schools in Appendix. The capacity of district buildings far exceeds current use and therefore allows for other restrooms to be used while repairs are made to exhaust fans. A ventilation dashboard clearly showing repair areas and opportunities for improvement will be placed on the district’s website and updated as repairs are completed. CARES Act funding will be used to repair/replace units in need of upgrades. 

11. Inspect and maintain local exhaust ventilation in areas such as kitchens, cooking areas, etc. Operate these systems any time these spaces are occupied. Consider operating these systems, even when the specific space is not occupied, to increase overall ventilation within the occupied building. 

OSN contracted an outside company, Hoodz, to inspect and clean kitchen exhaust systems once annually. The units are run everyday and will now be inspected twice per year. All kitchen ventilation systems were inspected and cleaned over the last year.  

12. Consider portable high-efficiency particulate air (HEPA) fan/filtration systems to help enhance air cleaning (especially in higher risk areas such as a nurse’s office or areas frequently inhabited by persons with higher likelihood of COVID-19 and/or increased risk of getting COVID-19). 

Designers can integrate features into the ventilation system that will provide benefits for the school occupants as well as the efficiency and longevity of the HVAC system. In addition, these features can reduce the need for expensive cleaning of the duct work and air handling units. 

Architects and engineers can integrate high-efficiency purification systems into school ventilation systems that will improve reduce the need for air handling repairs.  New technologies have recently surfaced to provide a supplemental layer of filtration. The district contracted an independent environmental team to assess indoor air quality. Environmental Health and Safety team members are working with an independent environmental company to research, test, validate, and recommend filtration units suitable for the district’s wide portfolio of schools. The results of the indoor air quality assessment will be placed on the district’s website.  

13. Generate clean-to-less-clean air movement by re-evaluating the positioning of supply and exhaust air diffusers and/or dampers (especially in higher risk areas). 

Supply and exhaust units are located on the roofs of commercial buildings and schools. Architect and design firms determined the placement of the units prior to construction commencement and roofing systems were built in consideration of this HVAC equipment. While the location of outdoor supply and exhaust air diffusers and dampers can be examined, it is not structurally or financially feasible to reconstruct the roofing systems because district facilities were designed with the current placement of these units. Moving forward, new construction will prioritize the of the units with the same contemplation and planning used with existing facilities.  

14. Consider using ultraviolet germicidal irradiation (UVGI) as a supplement to help inactivate SARS-CoV-2, especially if options for increasing room ventilation are limited. Upper-room UVGI systems can be used to provide air cleaning within occupied spaces, and in-duct UVGI systems can help enhance air cleaning inside central ventilation systems 

While trendy, classroom air purification systems are not sustainable due to required filter changes and electrical requirements. Some models also generate heat and create a humming noise that may distract students during instruction and independent work. UVGI systems use a form of ultraviolet light to neutralize airborne microorganisms and can be placed in classrooms or centralized air handler systems. 

Irradiation technology is under consideration at all district schools.  As technologies evolve, more methodical research and sampling is needed to make an appropriate decision for the wide range of building ages in the district’s portfolio. The district’s environmental health team and HVAC specialists are evaluating systems including charcoal filtration, bipolar ionization, and UV purification systems.  CARES Act monies will be used to install units as assessment results dictate.  

15. In non-residential settings, consider running the HVAC system at maximum outside airflow for 2 hours before and after the building is occupied. 

Building engineers and HVAC controls have the ability to maximize airflow two hours before and after school.  This process began at the beginning of the school year yet fresh air flow was tempered during winter months to maintain the proper functioning of heating systems. Outside air supply was increased in all district facilities this year.