Hazardous (Classified) Location : A location in which fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or easily ignitable fibers or flyings.
EESiFlo North America, Terminology and Glossary: Explosion Proof & Hazardous Areas, Pennsylvania, USA 2002, flowmeterdirectory.com/flowmeter_terminology, (Mrtm/ Explo Proof and Haz Areas - Amer) {561}