NEBOSH Practice Test

What zone classification represents an area where an explosive atmosphere is likely to occur during normal operations?

1. Zone 0

2. Zone 1

3. Zone 2

4. Zone 3

The correct answer is: Zone 1

Zone 1 is classified as an area where an explosive atmosphere is likely to occur during normal operations. This is a critical distinction in hazardous area classifications, as it indicates that the risk of an explosive mixture of air and flammable substances is significant enough that precautions need to be in place to mitigate potential hazards. This classification typically applies to environments where flammable gases or vapors are present and may form explosive atmospheres under normal circumstances, impacting the selection of equipment and safety measures in such areas. In contrast, Zone 0 is defined as a location where an explosive atmosphere is continuously present, while Zone 2 refers to areas where such an atmosphere is unlikely to occur during normal operations, and if it does, it will only exist for a short duration. Zone 3 is typically not included in the standard hazardous area classifications relevant to explosive atmospheres. Understanding these designations is essential for ensuring safety in environments where flammable materials are present.