Mechanical Considerations


Increased cleaning protocols should be developed, communicated, trained and implemented.

  • CDC guidelines
  • Clean desk policy to allow effective cleaning
  • Staff facility/equipment use protocols 
  • Housekeeping day and night protocols
  • Portable and/or robotic UV systems
  • Mist sterilization systems i.e. GenEon

controlling outbreaks in academic environments

  • Identify symptoms
  • Provide PPE
  • Relocate those showing symptoms to nursing station or isolation space
  • Develop communication plan to notify about possible contact
  • Develop protocol to handle quarantine of other individuals who may have been exposed
  • Look at spread potential to adjacent spaces or other building areas through systems
  • Develop protocol to handle air cleaning for space prior to re-entry (ozone, local HEPA filtration, combination unit with filtration and UV, etc.)
  • Report/track incident through defined policies

The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) recommends airborne exposure to the virus can and should be controlled. Changes to building operations can reduce airborne exposure.

  • Filtration
  • Outdoor air
  • UV technology
  • Humidity control
  • Emerging technologies

During and following the pandemic, the districts, administrators, and designers  should focus on increasing outside air to the spaces, treat return air and/or supply air to spaces via mechanical filtration, and maintain indoor comfort as defined by the design temperature and relative humidity.

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  • Increase mechanical outdoor air (OA)  as much as possible while ensuring comfort conditions are maintained
  • Verify that existing heating and cooling coils can handle increased amounts of mechanical OA
  • Opening of windows and doors should only be considered when no mechanical ventilation exists and/or air conditioning is not provided to the space
  • Disable any Demand Controlled CO2 Ventilation (DCV) and introduce maximum possible consistent OA flow
  • Apply highest minimum efficiency reporting value (MERV),  HEPA or MERV 14
  • Change start of operation hours (enable systems at 4 AM rather than 6 AM) and run DOAS constantly
  • Turn on exhaust fans and run DOAS as makeup air on school days only
  • Consider local UV-C or air ionization equipment in high density areas (waiting rooms, lobbies, etc.)
  • AHU’s and RTU’s, and HP’s
    • Increase filtration level
    • Verify OA level
  • Nurse Room
    • Treat as isolation room
    • Negatively pressurize nurse’s office (-0.015” to -0.5”) when possible
  • Filtration:  MERV 13 or above
    • Determine current size, depth and quantity of filters in existing equipment (AHU/RTU/DOAS)
    • Average SAR CoV2 particle size = 0.12 um (micrometer)
    • Determine supply fan ability to accommodate higher filter PD

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  • Create a health and safety committee
  • Develop policies for staff and contractor PPE requirements
  • Do not defer maintenance
  • Conduct semi-annual scheduled maintenance on HVAC equipment
  • Perform Checklist #1 (see below) during the summer prior to returning to school
  • Operate all HVAC in occupied mode for a minimum of one week prior to occupancy
  • Perform Checklist #2  (see below) during the week prior to returning to school

Checklist # 1: Complete prior to fall start classes

Review existing systems to ensure facilities have:

  • Proper air distribution
  • Proper operation of lavatories, sinks and associated handwashing equipment
  • Proper operation of control sequences to maintain required ventilation, temperature and humidity conditions
  • Completed preventative/deferred maintenance programs that may improve facility indoor environmental quality (IEQ)

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  • Maintain proper indoor air temperature and humidity levels
  • Monitor temperature and humidity levels
  • Verify proper separation between outdoor intakes and exhaust outlets
  • Consider having existing systems rebalanced to ensure proper building pressurization
  • Consider airflow and system capacities reviews
  • Maintain positive building pressure differential
  • Verify required coil velocities for indoor conditions
  • Verify outdoor airflow rates are correct
  • Verify filters are properly installed
  • Maximize filtration level based on equipment fan capability
  • Reduce or eliminate demand controlled ventilation systems (CO2 control)
  • Perform air flush of all spaces prior to building re-entry
  • Prepare domestic water systems:
    • Flush to remove potential contaminants from stagnant equipment, piping, fixtures, etc.
    • Have all building fixtures open at the same time
    • Flush domestic cold systems with all fixtures on a branch of piping opened simultaneously for a minimum of five minutes
    • Flush domestic hot systems with all fixtures on a branch of piping opened simultaneously for a minimum of 15 minutes
  • Reference Standard 188 and Guideline 12 (managing risk of Legionellosis associated with building systems)
  • Follow recommended equipment maintenance protocols
    • Conduct daily cleaning and air flushing:
      • Mechanical systems should be operated in occupied mode for a minimum period of two hours prior to building re-entry
      • Thoroughly Clean:
        • All areas that have been occupied
        • All restrooms
        • All food preparation areas
        • Accessible surfaces