What defines Class 1 Division 1 environments?

Class 1 Division 1 environments are defined by the presence of flammable gases and vapors that can exist under normal operating conditions. This means that in these environments, there is a continuous or frequently occurring risk of ignition because the hazardous substances are present consistently. This classification is integral in ensuring that appropriate safety measures, such as explosion-proof equipment and specific installation practices, are implemented to mitigate the risk of fire and explosions.

In Class 1 Division 2 environments, on the other hand, hazardous materials may only be present in abnormal situations, such as equipment failure or maintenance operations, which is why the other options do not accurately describe Class 1 Division 1 environments.