기술 상담

Computer chassis are typically equipped with many case fans, some are designed for exhaust and others for intake.  When intake fans’ combined airflow is greater than exhaust, a positive pressure is created inside the chassis.  Conversely, when the airflow is greater for exhaust than it is for intake, a negative pressure is created.

The major difference between positive and negative pressure is the way vents and various gaps are affected.

This photo shows an example of a modern high performance chassis with extra vents not occupied by case fans.  These vents can become either exhaust or intake depending on whether the chassis has positive or negative air pressure respectively.

*Dedicated vents aren’t the only places on a chassis that can act as pathways for airflow, gaps on the outside the chassis such as the one shown in this photo can also be affected.

The diagrams show that chassis with positive air pressure can prevent dust from penetrating into the chassis by use of filters on intake fans and forcing air out of the chassis through unfiltered vents and gaps. On the other hand, a chassis with negative air pressure draws in air from unfiltered vents and gaps that even with fan filters placed on key intake fans, dust can penetrate into the chassis easily.

The idea to use positive air pressure in designing dust-proof chassis comes from the concept of a cleanroom. The cleanrooms are used often in Hi-tech, medical, and food processing industries.  All cleanrooms, regardless of their levels and sizes, are built to maintain a positive pressure environment to prevent dust from entering the room.

Both Sugo SG03 released in 2007 and the Fortress FT01 released in 2008 are examples of chassis with positive air pressure design.  They have optimized support for high-end graphics cards and filters to prevent dust built ups for longer service life.