Installation of electrical equipment in hazardous areas is heavily regulated and controlled through codes and standards, issued by many countries or economic blocks.
IEC standards are widely adopted around the world, and standard number 60079-2 covers the protection of electrical equipment by pressurized enclosure. This standard was last updated in 2014 and is now in the final stages of review before publication. Expo is part of the review committee.
There are some significant areas of change in the new version of the standard that may simplify some projects without compromising safety, and Expo presented an overview of these changes at the recent Hazardex conference in the UK.
You can view the presentation here.