It is The primary reason to dry compressed air is to prevent either condensation or freezing of water vapor at lower temperatures. This category includes the drying of compressed air for instrumentation. In situations of extreme ambient temperatures, the formation of water or ice in the air lines can cause malfunctioning or stoppage of control instruments. While the broad category of “instrument air” is covered in this type of application, a similar circumstance could be encountered for plant air used for air tools, or operation of other pneumatic devices; compressed air for circuit breaker applications, and other cases where freeze-ups and air stoppage of compressed air is undesirable.