Good understanding on hazardous area classifications definitions is essentially important. Every chemical engineer should know about this area in well enough. You should know every inch in the plant site that is classified as hazardous area.
Hazardous Area Classification and definitions in every plant site can be known from engineering documents about the plant facilities. In general, it is included in Electrical section in engineering documents or sometime in safety section.
As per definition, hazardous area is area in plant site, where concentrations of flammable gases, vapors or dusts exist.
In such area, all electrical equipment should be explosion proof type. They should not be able to trigger an explosion due to arching or high temperature surface.
Top 5 Resources on Hazardous Area Classifications and Definitions
This is a complete list of resources that you could refer to when you need to check about hazardous area classifications and definitions.
A must reference for this topic. A solid resource that covers about hazardous area definition, history, divisions or zones for gas, vapors and dusts, gas groups, equipment protection level, temperature classifications, type of protection, ANSI/NFPA area description, equipment class and labelling.
Hazardous area classification for North America: classes, divisions, groups and temperature code.
Hazardous area classification for Europe: protection types, classes, divisions, groups and temperature code.
Hazardous locations based on National Electric Code (NEC): hazardous location types, hazardous location conditions, nature of hazardous substances, hazardous location equipment.
Hazardous area classifications and control of ignition sources. The explanation includes hazardous area classifications for flammable gases and vapors, zoning, selection of equipment, ignition sources identification and control, direct fired heater, hot oil system, process operating above auto-ignition temperature, lightning protection, vehicles, dust explosion.