Operatory Room Settle Time Calculator for Aerosol Generating Dental Procedures

Use this form to calculate settle time or turnover time in between patients in operatory rooms where aerosol generating procedures where used.  Enter your room dimensions and filtration device CFM rating to determine settle time. As recommended by Saskatchewan Health Authority for the COVID-19 PPE Rapid Update.

Need a dental calculator to determine ACH? Check out our dental operatory settle time calculator tool here: Air Changes Per Hour Calculator

You can also download a free air purifier worksheet for dental facilities here.

Check out our 550cfm HEPA air purifer here.

What is settle time?

The “settle time” is the amount of time needed to remove infectious airborne organisms from room air or infectious aerosols that may be created during an AGMP.

This begins when the source of infectious aerosols ends.
When a patient on continuous Airborne Precautions is moved out of the room.
Following an AGMP when a pathogen or virus (e.g., COVID-19) has the potential to be aerosolized during the procedure.

The “settle time” is used to guide if a N95 respirator needs to be worn while in the room or how long the room must sit before Housekeeping can begin cleaning.

The “settle time” should never impact patient care needs and should not delay essential patient or staff movement in and out of the room.

How is the room “settle time” determined?

To determine a specific “settle time” for a specific room, the number of Air Changes per Hour (ACH) must be evaluated as each room can be different (size, temperature, humidity, ventilation capacity, etc.).

The higher the ACH, the less time is required for settle time.

If the number of ACH for the patient room is known, a specific “settle time” can be calculated using the tool above

Then staff will know how long they must wear an N95 respirator or how long before Housekeeping can enter the room to clean.

Please note: the number of ACH does not reflect the direction of air flow (i.e., negative pressure vs positive pressure).

If the number of ACH is unknown, the “settle time” for a patient room has been determined to be 2 hours or 120 minutes.

What conditions must be in place when using a specified “settle time”?

Patient room door should remain completely closed, with the exception of essential patient/staff movement.

(For Canadian Offices) Posters to be displayed on the door can be found on Saskatchewan.ca/covid19-providers.