When you go for hazardous area classification, your land or construction site gets divided into different groups and subgroups. The zone system takes into consideration the hazardous material risks. While Zone 0 is the area where flammable gases or vapors are present for a long time, Zone 1 is the area where flammable gasses and vapors are generated during regular operational days.
Zone 2 covers the area where flammable gases are not likely to be present during regular operational days. Even if they are present, it’s for a very short period. This categorization takes into account gases, mists, and vapors.