Air flow rate or volume flow is a measure of the air flow generated by a fan.
Air flow rate is a measure of the cooling of electronic components, circuit boards, subracks and racks. In Europe, air flow rate is expressed in cubic meters per hour (cbm/h), while in Anglo-Saxon countries it is expressed in cubic feet per minute (cfm). There is a relationship between the two quantities: 1 cfm corresponds to 1.7 cbm/h or 0.472 l/s. Accordingly, 50 cbm/h corresponds to 29.5 cfm.
To increase airflow in racks, there are fan trays with multiple fans that have several times the airflow of a single fan.