“Intrinsically Safe” (IS) is a protection standard for safe operation of electronic equipment in explosive environments. The concept was originally developed for safe operation of process control instrumentation in hazardous areas, particularly around flammable and explosive products. ATEX is named after the French 'ATmosphère EXplosif'. All the 24 member countries of the European Union (plus Norway, Iceland and Liechtenstein) are subject to the directives. Manufacturers, who comply with its provisions and affix the CE and EX marking, are able to sell their equipment anywhere in the European Union.