The HVACR industry has rightfully pursued and embraced HFC refrigerants with lower global warming potential (GWP). Transitions to R-410A and R-404A were accomplished over time, requiring significant coordination with and planning by OEMs. As illustrated in Figure 1, these refrigerants can operate at pressures that exceed R-22, for instance, by over 50 percent. The new darling of the industry, CO2, only serves to raise the stakes in this high-pressure game. While the seals, compression ratios, efficiency ratings, and other considerations were painstakingly engineered, other system components were taken for granted.
So the refrigerants changed, but what about the standards governing products that transport and contain those refrigerants? UL 207 has provided a vehicle for the equipment manufacturers to deal with components that do not have individual pressure ratings sufficient to handle these new refrigerants. This involves certifying equipment as a system through various testing that essentially qualifies all components together.