A Class I Div. 1 purge system is typically called a Type X purge. A Type X purge system is used to provide, control, and monitor instrument air or some other inert gas in an enclosure containing electronic equipment intended to be mounted within a Division 1 hazardous location.
A Class I Div. 1 area is an area classified as containing ignition-capable concentrations of gas/vapors under normal operating conditions.
Going back to the purged enclosure, the electronics mounted within the enclosure are not suitable for operation within this hazardous area so it’s critical to maintain positive atmospheric pressure within the enclosure to maintain safety.
This is where the Class I Div 1. purge system is used. As soon as pressure is lost or drops below a set limit, the purge system will cut power to the enclosure. This guarantees safety.
The Class I Division 1 purge is also used to control the initial startup of the enclosure electronics by flushing the enclosure and its contents with the nonhazardous clean air or inert gas. Again, this allows the electronics mounted within the enclosure to safely start up and operate without fear of an explosion.