Purged and Pressurized Systems for Class I, Div. 1 & 2, and Zone 1 & 2 Hazardous Locations

Like most hazardous certified products, type X, Y & Z purged controllers and indicators have historically been designed and certified for use in the countries where they originated or intended to be used. This practice has required the individual specifying or purchasing the equipment to select controllers and indicators which meet the certification requirements for the country in which it is installed. This paper presents a summary of the requirements for purging as a method of protection for class I, div. 1 & 2 and zone 1 & 2 hazardous locations. These controllers and indicators are designed to meet North American NECreg/NFPAreg standards, the ATEX directive 94/9/EC and CE marking for the European countries and IEC 60079 standards worldwide. The paper also summarize the other methods of protection as they compare to purged and pressurized systems. Installation and maintenance procedures and safety issues for working with purged and pressurized systems are presented