Mechanical Considerations

Types of Pathogens.JPGCHANGING BUILDING OPERATIONS AND CLEANING PROTOCOL

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

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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

 

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