Which of the following refrigerants is a blend designed to reduce flammability?

• A. R22
• B. R407C
• C. R410A
• D. R134a

Answer: (B)

R407C is a refrigerant blend designed to reduce flammability compared to its predecessor refrigerants. It is a mixture of three different refrigerants: R134a, R125, and R32. The inclusion of R125 and R134a in this blend contributes to its reduced flammable potential, while maintaining energy efficiency and performance suitable for various applications in air conditioning systems.

Unlike R22, which has an ozone-depleting potential, R407C was developed as an environmentally safer alternative without the same level of flammability concern present in other blends. R410A, while also being a non-ozone depleting refrigerant, has different flammability characteristics and operates at higher pressures. R134a itself is not a blend and does not address flammability in the same way, as it is a single compound rather than a mixture designed to achieve specific performance properties such as reduced flammability. Thus, the properties of R407C make it a suitable choice among refrigerants aimed at minimizing flammability risks.