STEP-BY-STEP

Maximize ventilation at your business to prevent COVID-19

Your business should set up as much airflow as possible to be open to the public.

All businesses should get air moving when people are inside, to reduce the risk of COVID-19 transmission. Choose a method depending on what you can do at your business. 

See more ventilation guidance from the Department of Public Health. Email your ventilation questions to dph.doc.ventilation@sfdph.org.

1

Check your HVAC system (if you have one)

Work with building engineering, maintenance staff or a HVAC professional before you work on a mechanical ventilation system.

Disable demand controls so that fans are always on regardless of temperature.

Open outside air dampers to maximum, if you can. Minimize recirculated air.

Switch to the highest-rated filter for your system. Aim for MERV 13 or higher. Regularly check and replace your air filters.

Consider running your fans for 2 hours before your business opens, and after it closes to the public.

Make sure the room meets building code.

or

Get a portable air cleaner for each room

Make sure your air cleaner is certified for ozone and electrical safety. Get an air cleaner that can purify air for the room size you’re using. 

You can also build your own air cleaner. Tape a 20” by 20” MERV-13 air filter to the intake side of a 20-inch box fan, where air goes in. Make sure to only use the fan when there is someone in the room to watch it. It may overheat.

Place air cleaners in the middle of where people will be. Make sure the exhaust will not blow air from person to person

or

Keep all your doors and windows open

You do not have to keep doors and windows open if there will be a safety hazard, such as falling. Fire doors should be kept closed.

You can also use portable fans near windows to increase the fresh air from outside.  Make sure the fans are not blowing air from one person to another.

If you have ceiling fans, adjust them so air is pulled up towards the ceiling.

If you cannot keep doors and windows open, you can move your services outside, or to another room where you can do that.