In North America, the most widely used hazardous location classification system is defined by the National Fire Protection Association (NFPA) Publication 70, National Electric Code® (NEC) in Articles 500 to 506. These regulations specify the type of hazardous substances that are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
The NFPA establishes area classifications based on Classes, Divisions and Zones that when combined delineate the hazardous conditions of a specific area. This classification method provides a description of the hazardous material, and the probability that it is present, so that the appropriate equipment is safely installed and operated. The Occupational Safety and Health Administration (OSHA) has adopted these hazardous classifications from the NEC and they are defined in the 29 Code of Federal Register (CFR) 1910.399.
Almost all developed countries are members of the International Electrotechnical Commission (IEC). Positive pressure enclosures, or “welding habitats” work on the principle of overpressure. This protection principle is regulated by IEC standard 60079-13:2017. The IECEx certification scheme is regulated by the IECEx 02 IEC System for Certification to Standards relating to equipment for use in Explosive Atmospheres (IECEx System) IECEx certification is compulsory to operate electrical equipment in explosive atmosphere in most Countries outside Europe. Australia, New Zealand, UAE, Malaysia, and the Philippines accept IECEx certification directly.
ATEX Certification is the national certification standard of the European Union, and mandatory to operate equipment in explosive atmospheres in Europe. Certification is based on the ATEX directive 2014/34/EU with all equipment requiring a proper manufacturer’s EU Declaration of Conformity. For Zone 1 welding habitats this EU Declaration of Conformity must be based on a Notified Body issued EU–Type Examination Certificate for pressurized habitats (rooms) EN 60079-13.