Final answer:
LEED requires zero use of CFC-based refrigerants in new building HVAC&R systems.
Step-by-step explanation:
In the context of refrigerant selection for HVAC&R systems in new buildings, LEED (Leadership in Energy and Environmental Design) requires a minimum threshold of zero use of CFC-based refrigerants.
CFCs (chlorofluorocarbons) are synthetic chemical compounds that have been widely used as refrigerants, propellants, and solvents. However, they contribute to ozone depletion in the upper atmosphere.
Instead of CFCs, LEED recommends the use of environmentally friendly alternatives such as hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). These replacements include HFC-134a and HCFC-141b, which have lower ozone depletion potential.
By implementing the zero use of CFC-based refrigerants, LEED aims to promote sustainable building practices and reduce environmental impact.