Fieldbus in hazardous areas

摘要

Last month this department outlined the content of the FISCO [fieldbus intrinsically safe concept] IEC Technical Specification TS 60079-27. (See the December 2003 Networking & Communications department at www.isa.org/intech/200312c.) The principles underlying FISCO are the foundation for a companion nonincendive technique, which is applicable to Zone 2 or Division 2 locations - where ignitable concentrations of flammable gases, vapors, or liquids are not likely to exist under normal operating conditions. This combination of techniques has a common simple set of rules for creating a system and the associated documentation that can be used whatever the hazardous area classification. The resultant system - fieldbus nonincendive concept (FNICO) also has the merit of being internationally acceptable.