Clothes dryer installations that exhaust more than how many cubic feet per minute must have makeup air provided?

In the context of clothes dryer installations, the requirement for makeup air comes into play when the exhaust airflow is high. Specifically, when dryers exhaust air at rates over 200 cubic feet per minute (cfm), it is necessary to provide additional makeup air to replace the air being expelled from the structure.

This is crucial for maintaining proper air balance within the building. If sufficient makeup air is not supplied, it can lead to a negative pressure in the space, which might cause backdrafting of combustion appliances, hinder indoor air quality, and create an overall unsafe environment. Additionally, inadequate makeup air can affect the efficiency of the dryer.

In summary, the threshold for needing makeup air is established at 200 cfm, meaning any dryer that exhausts at or above this rate requires supplemental air to ensure safety and efficiency.