The “System Emissions Chart” contained herein is intended to serve as a means of estimating the annual refrigerant emission rate (grams per year) from new production A/C systems equipped with specified component technologies. It provides emission values for various component technologies that are currently available, and can be expanded as new technologies are commercialized. This document provides the information to develop an Excel file template “System Emissions Chart” for system emission analysis. The chart includes automotive compressor technologies for conventional mobile air conditioning systems as well as those using semi-hermetic compressors. This standard can be considered a companion document to SAE J2763 Test Procedure for Determining Refrigerant Emissions from Mobile Air Conditioning Systems. SAE J2727 estimates system emissions, taking into account production assembly variation and accounts for components that are 100% helium leak tested prior to vehicle final assembly. The results from SAE J2064 are used to better represent permeation emissions from different hose material and coupling configurations in this version. SAE J2763 may be used to quantify emissions from properly assembled systems.
Industry standards did not exist for measuring, or estimating, refrigerant emissions from mobile air conditioning systems when the original version of SAE J2727 was created in 2005. The 2005 version provided a method of rating emissions from A/C systems, based solely on component technologies used in the system, combined with expert input regarding relative emission rates of components. The 2007 revision was based on the 2005 version, enhanced with laboratory measurements and vehicle field test correlations, and replaced the rating system with an estimate of system emissions in grams per year. While the 2008 revision provided clearer definitions of sealing technologies and how to apply them to the SAE J2727 System Emissions Chart, even greater clarity is needed to accommodate the wide variety of system components and their possible connections to the A/C system. The current revision encompasses additional components, a consideration for the emission reduction value of effective Helium leak detection of components prior to vehicle assembly, and requires the use of SAE J2064 A/C hose permeation data to provide proper credit based on the actual emissions of the hose used. In addition, although the original refrigerant emission chart was based on R-134a, the current revision has been enhanced to allow the estimation of R-1234yf emissions as well as those of the R-134a.
The revisions in this document allow for more detailed component emission ratings for existing production manufacturing processes, including leak checking components using helium. Although some sectors of the international MAC industry have developed other emission measurement approaches, this standard has had a comprehensive ongoing relationship of vehicle and laboratory SAE testing procedures that has resulted in correlation of MAC system refrigerant emissions used in this document.