Ventilation FAQ

This webpage provides information about ventilation of buildings on SPU’s campus.

How do SPU buildings provide ventilation and improve air quality?

Campus mechanical systems are maintained to provide ventilation and thermal comfort as designed through the following activities:

  • Building mechanical systems have been set to provide the highest possible percentage of outside air, dependent on each building and system.
  • Air filters are in most buildings equipped with central heating, ventilation, and air conditioning (HVAC) systems are rated at MERV-13 or higher as recommended by the CDC and ASHRAE.
  • HVAC systems will normally be on a minimum of two hours prior to the start of the business day for multiple exchanges of interior air prior to occupancy.
  • Building HVAC systems continued to operate normally during the "Stay Home, Stay Healthy” period, even while buildings were unoccupied. The systems were not shut down due to decreased occupancy, but may be temporarily shut down for regular or emergency maintenance unrelated to COVID-19.
  • Laboratory ventilation systems operate continuously with 100% outside air supply that is not recirculated in the building and is exhausted directly to the outside.
  • In most cases, exhaust fans in restrooms operate continuously when buildings are occupied. Some restrooms are equipped with a wall switch operated by the occupant, in which case it’s suggested to keep toilet exhaust fans operating continuously. For restroom exhaust fans to work best, it is recommended to avoid opening operable windows in restrooms and keep restroom doors closed (or mostly closed for single restrooms not in use). Lids were added to toilet seats and should be closed prior to flushing.
  • In naturally ventilated areas (buildings without mechanical systems), operable windows should be open while spaces are occupied.
  • When possible, keeping conference room doors open can help promote good ventilation.

Report building HVAC issues by campus location to the Office of Facility and Project Management (Facilities) at 206-281-2330 or via service request to Please note that the increase in outside air percentage may mean decreased ability to control space temperature during extreme weather.

What is being done to verify building HVAC systems are operational, given COVID-19?

The University performs routine inspections to check HVAC systems for the following:

  • Fan systems are functional and operating.
  • Central HVAC fan filters are within acceptable operating ranges and replaced as necessary.
  • Fan filter racks are inspected for major gaps or damage.
  • Outside air ventilation rates set to provide as close to 100% outside air in recirculating HVAC systems where possible. SPU believes these mechanical systems are operating with 80-100% outside air.

Can I turn on a portable fan or space heater?

Yes, but the discharge airflow should be directed away from the body and face of other people to prevent potential transmission to nearby individuals. If you use a portable fan or space heater, you must follow all manufacturer instructions for use and maintenance for the specified model.

Can I use or purchase a portable air cleaner or air filter for my area? What kind of portable air purifier should I purchase?

Yes, individuals may use a portable air cleaner or air filter in their work area. Check with Facilities prior to use. Units with HEPA filters are preferable. Avoid ionization units — they generate harmful ozone. Follow the manufacturer’s recommendations regarding use and filter changes.

When used properly, portable air cleaners and air filters can help reduce the presence of airborne particles. However, a portable air cleaner should not be relied on to prevent COVID-19 transmission. The portable unit should be sized appropriately for the square footage where it will be placed.

Consult with the Environmental Protection Agency (EPA) Air Cleaners and Air Filters In the Home guidance document Follow all manufacturer instructions for use and maintenance for the specified model. Do not bring UV units to campus without pre-approval from Facilities.

What ventilation is provided in stairwells?

While some stairwells may have operable windows, stairwells are not provided with mechanical ventilation. This is a code and safety issue in order to keep stairs as free of smoke as possible if a fire were to occur in a building.

Can ultraviolet lamps be installed within our building’s HVAC system or within rooms?

Ultraviolet germicidal irradiation (UVGI) is a known technology used to reduce the transmission of airborne microorganisms, including bacteria, viruses, molds and other pathogens. However, the efficacy of high intensity UV irradiation against SARS-CoV-2 is not known. The Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) do not routinely review the safety or efficacy of such light, and therefore cannot confirm whether UVGI might be effective against the spread of COVID-19.

SSPU’s consulting Mechanical Engineer is currently recommending against its use stating that air moves too quickly through air handlers for this technology to be very effective. It also presents a health hazard and cannot be used in occupied spaces. SPU’s consulting Mechanical Engineer will continue to evaluate the changing technology, safety guidelines, and settings where upper-room UVGI might be appropriate, such as rooms with no mechanical HVAC systems.

How many air changes per hour are in my room?

Air changes per hour (ACH) is defined as the volume of ventilation air that is supplied and removed from the room every hour. The ventilation air can be through natural or mechanical ventilation systems and helps to remove contaminants from a room. The number of air changes per hour in each room in a building can vary throughout campus. In general, laboratories are typically supplied with 6–12 air changes per hour, and office areas are typically supplied with 4–8 air changes per hour, in accordance with the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) standards

If you notice evidence of inadequate air quality in your space (e.g., air seems stuffy or stagnant) or thermal comfort, please request an evaluation. Contact Facilities at 206-281-2330 or make a service request at

Has SPU limited use of certain rooms due to air exchange capacity?

Yes, SPU is limiting the use of certain campus facilities due to ventilation. For current limitations, see the list of SPU Closed or Restricted Campus Locations.

Still have questions?

Questions can be emailed to SPU’s COVID-19 Decision Group at