Y and Z Equipment
If you are operating a control room with a classification from Division/Zone 1 to Division 2/Zone 2 you will require a type Y purging system.
Control rooms with the need to go from Division 2/Zone 2 to unclassified will require a type Z purging system.
Type Y and Z purging systems don’t require all power systems to be taken offline immediately in the event of a negative-pressure occurrence.
It is however recommended—for safety—that in the event of losing positive air pressure that you do turn off power systems as soon as possible (if you are not monitoring potentially flammable gases and vapors).
When it comes to positive air pressure control rooms—safety is key. Not only is it the paramount safety of your employees, but also for the equipment that is stored in your control enclosure/room… which are likely some of the most expensive assets in your physical environment.