Profibus System Integration PDF 4.03MB - Schneider Electric

EnvironmentInstrumentation management is dependent upon the environmental constraints andregulatory standards for applications in a dangerous environment.The specific EU directives are as follows:• The directive “users” 99/92 specifies the constraints for sites owners regarding thesafety of the workers and environmental protection.• The directive “manufacturers” 94/9 specifies the constraints for materialmanufacturers.These directives are more commonly known under the name of ATEX (ATmosphereEXplosive)For more details, see the website: http://ec.europa.eu/enterprise/atex/indexinfor.htmThe European directives identify several classification criteria:• The type of industry• The nature of the atmospheric risk (gas or dust)• The risk level in each specified danger zoneThe following table summarizes this classification:Area ClassificationZone CriteriaGasesDustsZone 0 Zone 20Zone 1 Zone 21Zone 2 Zone 22xxxPresent continuously or for longperiods(>1000hrs per annum)Likely to occur in normal operationoccasionally (>10hrs, >1000hrs perannum)Unlikely to occur in normal operation,If it does will only be for short perioda(>10hrs per annum)13