The purpose of this SAE Recommended Practice is to establish uniform test procedures for measuring and rating air delivery and cooling capacity of truck cab air-conditioner evaporator assemblies. It is the intent to measure only the actual cooling capacity of the evaporator. It is not the intent of this recommended practice to rate and compare the performance of the total vehicle air-conditioning system. This procedure is designed to provide truck manufacturers and air conditioning system suppliers with a cost-effective, standardized test method and calculations for measuring and rating air delivery and cooling capacity of truck cab air-conditioner evaporator assemblies. This procedure relates to HFC-134a (R-134a) refrigerant system.