Building Ventilation and Filtration Systems

Updated January 20, 2023 | 1:15 p.m.

This webpage provides information about the heating, ventilation, and air conditioning (HVAC) systems in our buildings and how we are adjusting them in response to the COVID-19 pandemic.

UCI is taking steps to ensure campus ventilation and filtration systems provide appropriate COVID-19 risk mitigation.

Building Occupancy

The operational hours for the building HVAC systems are the same as before the pandemic, but with an increase of two hours prior and two hours after operational use.

Beginning July 6, 2021, campus buildings will be unlocked 7:00a.m.-9:00p.m. to support approved faculty and staff returning to campus. HVAC systems have been maintained in all buildings and will be fully functional as the campus community returns.

Air Quality and Heating Ventilation and Air Conditioning (HVAC) System

Indoor air quality and heating ventilation and air conditioning (HVAC) systems influence on the spread of COVID-19 is a major concern for the campus. Facilities Management continuously monitors the recommendations and guidance from the WHO, CDC, and American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE). Based on the recommendations, Facilities is maximizing outside air, operating additional hours to flush pre and post occupancy, and utilizing filtration beyond industry standard where possible. Facilities reminds you that the highest probability of spread continues to be close contact, with physical distancing, the use of a mask, and hand-washing the best defense against the spread of COVID-19.

For common questions regarding air quality in UCI facilities related to COVID-19, please visit the HVAC FAQs.


Facilities Management has had continuous operation of heating ventilation and air conditioning systems throughout campus. Since COVID began, we did not shut down buildings, even though there was a curtailment of classes and work on campus. That also means that we didn't curtail or shut down our maintenance program. We continued all maintenance on campus throughout the heating ventilation and air conditioning (HVAC) systems, which puts us in a much better position coming back to campus as those systems had no stagnation and were maintained throughout the entire time.p

HVAC filters are rated in MERV ratings from 1 to 20, and 17 through 20 are what are referred to as HEPA filters. HEPA filters have the highest efficiency and remove the smallest particles from the air. Unfortunately, those filters are not compatible with the air handling units and air conditioning systems that we have on campus.

Industry standard for places like grocery stores, restaurants, and other common buildings that you might travel to is a MERV-8 rated filter. A home furnace might have a MERV-8 rated filter. These filters are utilized in some campus trailer and temporary buildings. UCI buildings with small air handlers were MERV-10 and are being upgraded to a MERV-13 rated filter. The MERV-13 level of filtration is the ASHRAE recommended filter in response to COVID-19. UCI buildings with larger handlers such as Aldrich Hall, Biological Sciences 3, and Engineering Hall all have MERV 15 filters. MERV 15 filters are used exclusively throughout the campus in our large air handlers and are several steps above the ASHRAE recommendation.

For more information on how UCI is handling indoor air quality as people return to campus, watch Anteater Insider Live: Episode 2 | The Health of Indoor Air.


Facilities Management maintains air conditioning and ventilation systems and replaces air filters on a schedule throughout the year. Filtration further mitigates risk of transmission in buildings with recirculated air. As air moves through a building's HVAC system, air filters trap and collect large and small particles such as dust, allergens and microorganisms.

UCI trailers use filters with a MERV 8 rating that are effective in filtering particles such as mold spores, cooking dusts, hair spray and furniture polish. MERV 8 is industry standard.

UCI buildings with small AHUs use filters with a MERV 10 rating that are effective in filtering particles such as lead dust, flour, auto fumes, and welding fumes. Facilities Management recommends these filters be upgraded to achieve a MERV 13 rating and the ability to filter particles such as bacteria, smoke, and sneezes.

UCI buildings with large AHUs use filters with a MERV 15 rating that can filter particles similar to those as MERV 13 filters, but with greater efficacy.

Not all building HVAC systems can handle the filter upgrades without negatively impacting the system. Increasing filtration to levels beyond what the fans can handle results in a high pressure drop (the pressure drop means air will no longer move through the filter cutting off supply to the zones). In many cases cutting off airflow through the system also overheats the compressors resulting in mechanical damage and loss of all cooling to the building.

Prior to making any filter upgrades, confer with the team of subject matter experts with EHS and FM.

Indoor Environmental Quality

According to the Center for Disease Control and Prevention (CDC), indoor environmental quality (IEQ) refers to the quality of a building’s interior environment in relation to the health and wellbeing of those who occupy space within it. IEQ is determined by many factors, including lighting, air quality, and damp conditions.

For common questions regarding indoor environmental quality in UCI facilities related to COVID-19, please visit the EHS COVID-19 FAQs.

The University of California, Irvine (UCI) has a method for managing indoor environmental quality (IEQ) issues. The methods goals are intended to:

  • Provide a means for reporting and documenting IEQ concerns to Environmental Health & Safety.
  • Establish a consistent IEQ assessment process.
  • Ensure campus compliance with applicable regulations and recognized guidelines.
  • Minimize the effects of poor IEQ on employee/building occupant health.
  • Prevent building-related illnesses.
  • Direct the proper response actions for microbial growth remediation, water intrusion events, and construction project impact on indoor environmental quality.

Submit concerns regarding indoor environmental quality through Report a Safety Concern.

Propping Open Doors

For fire prevention and life safety reasons, do not ;prop open:

  • Entry doors
  • Fire doors
  • Laboratory doors
  • Security access doors

Before propping open doors, please contact EHS at

For Facilities Management related concerns or requests: