Air Vacuum Corporation is the industry's innovator and leader on "hoseless"​ and 100% vertical & horizontal airflow engine exhaust removal. The AIRVAC 911® Engine Exhaust System utilizes the natural upward movement of air through its unique "coanda"​ airflow pattern. The system eliminates the pockets of stagnant air that horizontal only units may create.The AIRVAC 911® Engine Exhaust System creates a uniform ceiling to floor movement of air and without any heavy unidirectional drafts. In many applications, one AIRVAC 911® unit will perform more effectively than two horizontal type units and our multi unit installation approach simulates a sprinkler fire suppression system by addressing the whole apparatus area together.Headquartered in Dover, NH, Air Vacuum Corporation has been manufacturing and installing the AIRVAC 911 system for over 20 years and is leading the industry in air filtration systems for fire departments and other enclosed apparatus stations.