UCLA Ventilation Systems FAQ

Air Quality Related to COVID-19 Ventilation

  • Can SARS-CoV-2 (COVID-19) be transmitted via existing air handling systems? How much do HVAC improvements reduce the risk of illness?
  • Evidence suggests that transmission between persons is typically the result of large droplet transmission at a short-range (e.g., cough or sneeze) with limited transmission via touching a contaminated surface. Case studies of “community spread” highlight the potential for smaller aerosolized droplets (such as those emitted by all persons when they breathe, speak or laugh) could also transmit the virus. Infectious diseases like COVID-19 can be controlled by interrupting the direct and indirect transmission routes used by the pathogen. The direct spread of pathogens is the primary method of disease spread. Controlling direct spread primarily involves managing human factors and non-pharmaceutical interventions, or NPIs (e.g., distance, density, hygiene, face coverings etc.) and these cannot be effectively managed or controlled via building mechanical systems. However, we can help mitigate the risk of indirect spread of this disease via aerosolized particles by increasing fresh air delivery to spaces and enhancing our building ventilation systems filtration where practical.
  • What is the process for assessing and making adjustments to HVAC systems in UCLA buildings?
  • Facilities Management Utilities Engineers have been actively engaged in evaluating the hundreds of campus buildings and making alterations to filtration and airflow where possible. Initial efforts focused on general assignment and departmental classrooms and then addressing building-wide evaluations, modifications and adjustments.
  • What can be done to reduce the risk of COVID-19 transmission via air handling systems? Is there a set of guidelines/recommendations you can share for how to improve air circulation in classrooms, residence halls, and common areas like dining halls where possible?
  • In general, reducing the risk of pathogen spread via building systems includes the following methods:

      •  Increase fresh outdoor air and/or overall airflow delivered to a space.
      •  Provide highly effective air filtration within mixed air systems.
      •  Identify areas not served by mechanical ventilation systems, or with limited ventilation and consider alternative measures/augmentations that can be applied to mitigate risks in those spaces.
      •  Practice physical distancing, face coverings and hygiene.

    Most buildings on campus are already ventilated beyond design per the American Society of Heating Refrigeration & Air Conditioning Engineers (ASHRAE) 62.1. Facilities Management (FM) has been making interventions when possible to provide additional fresh air and improve building filtration. For spaces without adequate outdoor air and/or filtration (MERV 13), the university will provide portable air purifiers for multi-occupancy spaces including classrooms, conference rooms and shared offices, where it is likely non-vaccinated individuals will occupy the space.
  • Should HEPA filters be used in all Air Handling Systems? Is UCLA updating filtration in buildings?
  • Unless a building air system is designed to accept a HEPA filter, installing one may actually cause so much resistance that it actually lowers airflow to a space, and can damage installed systems. CDC, ASHRAE, and UCLA instead recommend installing higher Minimum Efficiency Reporting Value (MERV) air filters when feasible. Most of our facilities already utilize the recommended MERV 13 or higher filters, and other buildings with fan coil or package units have been increased as much as operationally feasible.
  • Should campuses run HVAC systems at 100% outside air to increase ventilation?
  • Some of our campus buildings, including most laboratory spaces, already operate using 100% outside air systems. However, buildings served by mixed air systems have not been designed to run at 100% outdoor air—doing so could cause conditions that damage building HVAC systems and create unintended indoor air quality issues. For recirculating air systems, UCLA is implementing alternate strategies that increase fresh air delivery and filtration. In general, most mechanically ventilated buildings on campus supply airflow at rates that exceed industry best practice (ASHRAE 62.1). These ventilation rates are based on maximum occupancy. Since our building density is expected to be reduced due to increased telecommute and hybrid scheduling for the foreseeable future of work, and decreased classroom occupancies, fresh air rates supplied per person are multiple times higher than the recommended minimums.
  • Should campuses run HVAC systems 24/7?
  • Operating all building HVAC systems 24/7 during unoccupied periods of the day is not practical or sustainable, nor would it provide benefit to facility occupants when the building is empty.
  • Did UCLA completely shut down HVAC systems during the “Stay-at-Home" advisory, and are there plans to check for mold growth and Legionella in the water systems?
  • While the majority of UCLA faculty, staff and students were learning and working remotely at the onset of the pandemic, most UCLA properties were operational and all critical infrastructure and building needs were being maintained by FM during the COVID-19 “stay-at-home" period. In preparation for a fall return to campus instruction, all HVAC, plumbing and other mechanical systems have been maintained in accordance with Centers for Disease Control and Prevention (CDC) and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommendations.
  • Should people open windows to get fresh air exchange. Is this true for all rooms?
  • Opening windows can provide additional ventilation in some spaces, and would be appropriate in locations such as multi-occupancy offices (if served by a non-dedicated recirculating ventilation system), dorm rooms or naturally ventilated spaces. However, this practice in some cases can cause issues around temperature, humidity and airflow. Make sure that there are no significant unintended negative consequences when doing so—do not open windows if doing so poses a safety or health risk for occupants, including children (e.g., a risk of falling or when the campus Air Quality Index (AQI) exceeds 150). It is important to ensure that air currents do not create airflows from one person directly towards another. If your workspace is on the list of spaces that does not meet the standard for air flow or filtration without additional mitigation, opening windows during normal operating hours could be beneficial.
  • Should employees bring in personal fans? Do those help?
  • Personal fans are discouraged at this time, as they may help spread the virus depending on how they are used; the air-conditioning systems are still cooling as designed.
  • Should air purifiers be used? I want to purchase an air cleaner for my dorm or office, what should I purchase?
  • Portable Air Purifiers will not be provided campus‐wide and will be placed strategically where warranted. If MERV-13 filters cannot be installed in a building or the HVAC system cannot provide adequate ventilation, the university will provide a portable air purifier to filter and re-circulate air within each multiple occupancy space, as well as naturally ventilated spaces with multiple occupancy (e.g. Moore Hall classrooms). If a housing unit does not meet the ventilation and filtration standards (e.g. Hitch, Saxon, Sunset Courtside), a portable air purifier could be appropriate if it is likely unvaccinated individuals may occupy the space.
  • Where should Air Purifiers/Cleaners be placed?
  • Portable Air Purifiers deployed on campus must be placed strategically to ensure the air in the room is circulated effectively and “dead zones”—where air becomes stagnant—are minimized, yet also do not create airflows from one person directly towards another. Steps should be taken to ensure the air intake is unobstructed by furniture and the exhaust is able to move air as far as possible before being deflected or drawn into a return or exhaust grille. Also, they should be placed opposite open windows, not next to them, and near the middle of the wall, four (4) inches away from the wall.
  • How should Air Purifiers/Cleaners be operated in Classrooms?
  • The units must remain operational while the room is occupied and continue running after the occupants have left. Unless departments have staff dedicated to turning them on and off each morning and night, they should simply be left on overnight to ensure they are operating when the rooms are occupied in the morning.
  • How often are our HVAC systems checked and maintained?
  • Most HVAC systems are continuously monitored utilizing building management systems (BMS) and a network of sensors. As part of FM’s comprehensive preventative maintenance program, skilled technicians inspect, clean and maintain building air-handling systems biannually. Preventive maintenance includes:

      •  Vacuuming and cleaning air intakes and catch basins and air-handling rooms
      •  Washing air handler fins and coils
      •  Check and replace all pre-filters and filters according to a set preventative maintenance schedule, more often on smaller buildings.
      •  Cleaning and treating the water in all closed-loop systems
  • Has the University considered putting UV lights or extra HEPA filters in the return air plenums?
  • Unlike HVAC system performance, filtration and ventilation, neither CDC nor ASHRAE have issued specific suggestions for the addition of UV or HEPA filtration to building-wide HVAC systems. Given the uncertainties associated with the efficacy of HVAC system UV disinfection for COVID-19, UV systems are not expected to be used widely on campus at this time.
  • May I purchase a HEPA system outside of UCLA?
  • You may, however, all portable indoor air cleaning devices sold to people or businesses in California are required to be certified by CARB (California Air Resources Board). A searchable list of CARB-certified air cleaning devices is provided here
  • Are the Medify model MA-14 and MA-18 HEPA Air Purifiers approved for use in California? If you try to order the Medify Air Purifier on Amazon you may receive the following note: "This product does not meet California air cleaner regulation requirements, and cannot be shipped to California."
  • Yes, the Medify HEPA air purifiers are approved for use in California. The warning on Amazon is a well-documented technical glitch which is causing the Amazon ordering issue. The glitch is discussed extensively in the customer questions section. Customer feedback on Amazon recommends buyers order directly from the Medify website.
  • If the HVAC system is appropriate, do I still need to wear a face covering?
  • Yes, it is essential that we keep wearing face coverings for the duration that it is required under federal and state laws (including Cal/OSHA requirements for workplace settings), with limited exceptions (e.g., when alone in your own living space, when eating/drinking, when everyone in the space is vaccinated, etc.). Improving HVAC system ventilation does not interrupt the direct transmission of COVID-19 from person to person. Direct transmission appears to be the primary method of COVID-19 spread.
  • Can people congregate in hallways outside classrooms?
  • While there are several restrictions being lifted with the state reopening on June 15, 2021, there are still situations in which people are expected to continue wearing face masks and follow distancing rules, particularly when congregating indoors. When waiting to enter a classroom, people are encouraged to keep indoor interactions with other people short and distanced to the extent feasible. It is recommended that individuals avoid congregating in hallways and instead wait outdoors when feasible.
  • Are bathrooms safe to use?
  • Yes, bathrooms and locker rooms have negative exhaust ventilation systems. As a precaution, avoid overcrowding and consider waiting outside when already occupied at more than 50% occupancy. FM Custodial Services are cleaning all campus bathrooms daily in accordance with public health guidance.
  • Can faculty still hold office hours in their offices?
  • Most of the campus buildings have acceptable ventilation to support multi-occupancy. In spaces that do not meet the ventilation standard: served by recirculating fan coil systems without MERV 13 filtration, faculty are encouraged to adhere to the following guidance during multi-occupancy:

      •  Get vaccinated
      •  If not, consider virtual meetings or seek alternate spaces that can accommodate physical distancing for multi-occupancy
      •  Open operable windows when safe and outdoor UCLA Air Quality Index (AQI) is below 150.
      •  Request a portable air purifier if it is likely unvaccinated individuals may occupy the space.
  • Can “higher risk” activities continue indoors, such as playing musical instruments, singing and dancing? 
  • Activities that have a higher rate of aerosol generation should be considered higher risk and may require additive control measures to effectively mitigate the risk. For example, music (wind instruments and choir), fitness and exercise/athletic activities (which require higher levels of exertion) or spaces where louder speech or projection of your voice is required (theater). Additionally, spaces where physical distancing is challenging (i.e., in-person labs) or where the use of face coverings is not feasible (i.e. playing wind instruments) may require additional considerations to effectively manage the associated risk. Activities identified as higher risk may require supplementary control measures such as:

      •  Administrative controls: decreased density, increased physical distancing, increased cleaning frequency, staggered occupancy, etc.
      •  Engineering controls: portable air purifiers, Plexiglass barriers strategically placed where applicable (e.g., customer facing operations, cash registers, etc.)
      •  Personal Protective Equipment (PPE): increased respiratory protection (i.e. N95), face shields, etc.