Assure ducting is the proper measurement - if it is much too smaller, it is going to restrict airflow, and if the ducting is too big, it is going to cause extreme sound. Air recirculation must be deemed for if a commercial kitchen air flow process is to operate properly. https://commercialkitchenextracts90011.is-blog.com/43706543/details-fiction-and-grease-tight-extract-ductwork