By Michael Camber
Compressed air dryers are commonly rated to achieve a specific moisture level (e.g. 40°F pressure dew point) for a certain volume of air flow (cfm). This nominal flow rating is typically based on a set of standard conditions (100 psig, 100° F inlet temperature, and 100° F ambient temperature). In practice, your actual conditions can change from day to day and are rarely the standard conditions, and the dryer may be over or undersized depending on how it is selected.