SAE J2772_201909

This Standard is restricted to refrigeration circuits that provide air-conditioning for the passenger compartments of passenger and commercial vehicles. This Standard includes analytical and physical test procedures to evaluate refrigerant concentration inside the passenger compartment. In the early phases of vehicle evaluation, usage of the analytical approach may be sufficient without performing physical tests. The physical test procedure involves releasing refrigerant from an external source to a location adjacent to the evaporator core (inside the HVAC module). An apparatus is used to provide a repeatable, calibrated leak rate. If the system has multiple evaporators, leakage could be simulated at any of the evaporator locations. This standard gives detail information on the techniques for measuring R-744 (CO2) and R-1234yf (HFO-1234yf), but the general techniques described here can be used for other refrigerants as well. This standard is being updated to include references to the United States Environmental Protection Agency’s Significant New Alternatives Policy (SNAP) use restrictions with regard to R-744 and R-152a (now supported as a secondary loop application only). The standard was originally developed to provide a consistent method for measuring refrigerant concentrations in a motor vehicle to be used in conjunction with risk assessments that are done for new refrigerants being developed for mobile air conditioning systems. This standard has not been updated for heat pump systems that use an interior condenser for heating. Interior condensers may create a new risk associated with a high-pressure heat exchanger in the cabin interior air flow path. Manufacturers should appropriately consider additional risks associated with using an interior condenser heat exchanger.