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Ventilation guidance for custodians

Important information related to ventilation and air purification has been issued by the DOE to school custodian engineers to clarify guidance for winter weather operation of school buildings in light of COVID-19 policies and procedures. 

General comments

  • Custodian engineers or their staff will check building HVAC systems daily for proper operation. Any deficiencies that cannot be addressed at the building level will be reported to the Deputy Director of Facilities.
  • CO2 readings will be taken from every occupied classroom weekly, and other spaces as requested. Readings should be less than 500 ppm below the outside ambient level, or no more than 800 ppm total. Custodian Engineers are encouraged to share readings with space occupants.
  • Work with Principals to ensure COVID signage is properly maintained and displayed.
  • Custodians are required to maintain a 30 day supply of all PPE for school buildings.
  • Building HVAC equipment should be started 2 hours prior to occupancy, and operated one hour after occupancy.
  • Adjust heating set points if required to maintain space temperatures.
  • Work with building staff to ensure all supply and return/exhaust grilles are free of obstructions.
  • Ensure restroom exhaust fans are functional and operating at all times.
  • Inspect and maintain local exhaust ventilation in areas such as kitchens, cooking areas, etc. Operate these systems any time these spaces are occupied.

MERV 13 filters

  • If a building is served by central HVAC systems, custodians will be receiving replacement filters rated for MERV 13.
  • For classrooms served by central HVAC systems using MERV 13 filters, systems can be operated with regular return/mixed air (100% outside air supply is no longer required, but building controls should allow for increased outside air flow based on outside air temperature). No other mitigating measures (air purifiers, open windows, etc.) are required, although these additional measures can continue based on equipment availability, weather conditions, etc.
  • Regularly inspect filter housings and racks for proper filter fit, and seal any gaps to prevent bypass.

Operable windows

  • Outside windows that provide the primary source of ventilation air can remain open during cold weather, as building heating systems are sized to compensate. NOTE – this does not mean all windows should be open, or that each window needs to be open more than a few inches. 2-3 windows per room, opened 3 inches or so each should be sufficient to provide enough air to ventilate the space when considering occupancy and other mitigating measures.
  • Building radiator systems are designed to operate using convection. In colder temperatures, the temperature differential between inside and out increases that convection effect. Opening windows both top and bottom is helpful.
  • In moderate weather, opening windows prior to building occupancy can increase the air flow of each space. However, in colder weather, this may not be possible. If opening the windows does not allow for adequate warm-up of the space, it should not be pre-ventilated.
  • Buildings using windows for ventilation should start their heating plants earlier than usual to overheat the building prior to occupancy. If additional labor hours are required, custodians should reach out to their DDF for approval. Hours should be coded to 202SCV.

Air purifiers

  • The DOE has purchased 60,000 HEPA-rated air purifiers for use in schools, with 30,000 delivered as of Dec.11, 2020, and 30,000 more scheduled to arrive through January.
  • These purifiers can be used in spaces to supplement existing ventilation systems.
  • Purifiers should be installed in proximity to the room occupants.
  • For classroom and office use, filter elements should last approximately 1 year. Replacement filter elements have been ordered and will be provided to schools in 2021.