Significant New Alternatives Policy (SNAP)

Acceptable Substitutes in MVAC: Passenger Air Conditioning in Buses and Trains

You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more.Substitutes are reviewed on the basis of environmental and health risks, including factors such as ozone depletion potential, global warming potential, toxicity, flammability, and exposure potential. Lists of acceptableHelpacceptableThis designation means that a substitute may be used, without restriction, to replace the relevant ODS within the end-use specified. For example, HCFC-22 is an acceptable substitute for R-502 in industrial process refrigeration. Note that all SNAP determinations apply to the use of a specific product as a substitute for a specific ODS in a specific end-use. and unacceptableHelpUnacceptableThis designation means that it is illegal to use a product as a substitute for an ODS in a specific end-use. For example, HCFC-141b is an unacceptable substitute for CFC-11 in building chillers. Note that all SNAP determinations apply to the use of a specific product as a substitute for a specific ODS in a specific end-use. substitutes are updated several times each year. The list of acceptable substitutes are shown below.

Note: SNAP-related information published in the Federal Register takes precedence over all information on this page.

Substitute Trade Name Retrofit/New ODPHelpODPA number that refers to the amount of ozone depletion caused by a substance. The ODP is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11. Thus, the ODP of CFC-11 is defined to be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0. The halons have ODPs ranging up to 10. Carbon tetrachloride has an ODP of 1.2, and methyl chloroform's ODP is 0.11. HFCs have zero ODP because they do not contain chlorine. A table of all ozone-depleting substances ( shows their ODPs, GWPs, and CAS numbers. GWPHelpGWPThe index used to translate the level of emissions of various gases into a common measure in order to compare the relative radiative forcing of different gases without directly calculating the changes in atmospheric concentrations. GWPs are calculated as the ratio of the radiative forcing that would result from the emissions of one kilogram of a greenhouse gas to that from the emission of one kilogram of carbon dioxide over a period of time (usually 100 years). Gases involved in complex atmospheric chemical processes have not been assigned GWPs. See lifetime. ASHRAEHelpASHRAEASHRAE is an international organization that establishes standards for the uniform testing and rating of heating, ventilation, air conditioning, and refrigeration equipment. It also conducts related research, disseminates publications, and provides continuing education to its members.
SNAP Listing Date Use Conditions
Evaporative Cooling   N 0 N/A N/A June 16, 2010  
Free Zone (HCFC Blend Delta) Free Zone/ RB-276 R/N 0.013 1,592 A1 September 5, 1996  
Freeze 12 Freeze 12 R/N 0.013 1,606 A1 September 5, 1996  
GHG-X4 GHG-X4, Autofrost, Chill-it R/N 0.045 1,478 A1 September 5, 1996  
HFC-134a 134a R/N 0 1,430 A1 October 1, 2004;
June 16, 2010
Hot Shot Hot Shot, Kar Kool R/N 0.098 3,337 A1 September 5, 1996  
R-125/R-134a/R-600a (28.1/70.0/1.9) NU-22 old composition R/N 0 1,990 A1 June 16, 2010  
R-401C   R/N 0 933 A1 September 5, 1996  
R-407C Suva 407C, Klea 407C R/N 0 1,770 A1 October 1, 2004;
June 16, 2010
R-407F  Genetron Performax LT R/N 0 1,820 A1 October 4, 2011  
R-410A AZ-20, Suva 9100, Puron N 0 2,090 A1 October 1, 2004;
June 16, 2010
R-417A ISCEON 59, NU-22 R/N 0 2,350 A1 June 16, 2010  
R-422B ICOR XAC1, NU-22B R/N 0 2,530 A1 March 29, 2006;
June 16, 2010
R-422D ISCEON MO29 R/N 0 2,730 A1 September 28, 2006;
June 16, 2010
R-424A RS-44 R/N 0 2,440 A1 January 2, 2009;
June 16, 2010
R-426A RS-24 R/N 0 1,510 A1 June 16, 2010  
R-427A Forane 427A R 0 2,140 A1 January 2, 2009;
June 16, 2010
R-434A RS-45 R/N 0 3,250 A1 January 2, 2009;
June 16, 2010
R-438A KDD5, ISCEON MO99 R/N 0 2,270 A1 October 4, 2007;
June 16, 2010
RS-24 (2002 formulation)   R/N 0 1,510 A1 June 16, 2010  
SP34E SP34E R/N 0 <1,470 A1 June 16, 2010  
Stirling Cycle   N 0 N/A N/A June 16, 2010  

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