Group IIB : Above ground installations with ethylene or equal atmospheres. This group most closely matches Group C in the United States and Canadian classifications
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}