Refrigeration Operating Engineer License Practice Exam

The classification of refrigerants is based on their chemical composition and their environmental impact, particularly regarding ozone depletion. Hydrochlorofluorocarbons (HCFCs) are a group of substances that were developed as transitional replacements for chlorofluorocarbons (CFCs), which are known to cause ozone depletion.

In this context, R-22 and R-123 are both recognized as HCFC refrigerants. R-22 (chlorodifluoromethane) has been widely used in residential air conditioning and refrigeration applications. R-123 (dichlorotrifluoroethane) is primarily used in chillers for commercial refrigeration.

Both of these substances have lower ozone depletion potential compared to their CFC counterparts, which makes them less harmful to the ozone layer, though they are still being phased out due to their global warming potential.

In contrast, the other groups of refrigerants mentioned in the choices do not belong to the HCFC category. R-11 and R-12 are CFCs, while R-134a and R-125 are hydrofluorocarbons (HFCs). R-11 and R-115 are also CFCs and not included in the HCFC