When installed, the AFM-KIT airflow monitoring system can operate an optical LED or audible alarm, or send a signal to a control device when airflow falls below 8.2 feet per second. Decreased airflow can be caused by fan filter clogs, foreign materials coming into contact with the fan blade or fan failure. The air flow monitor measures positive airflow when it is mounted to the front of the fan and negative airflow when mounted to the intake side.