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  2. Significant New Alternatives Policy (SNAP)

Substitutes in MVAC: Passenger Air Conditioning in Buses and Trains

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 acceptableThis 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 unacceptableThis 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 substitutes is shown below.

Many acceptable substitutes under SNAP may be restricted under the Technology Transitions Program. For more information on Technology Transitions Program restrictions, visit: https://www.epa.gov/climate-hfcs-reduction/technology-transitions-program.

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

Filters              
Substitute Trade Name(s) Retrofit/New ODPA 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 (https://www3.epa.gov/ozone/science/ods/index.html) shows their ODPs, GWPs, and CAS numbers. GWPThe 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. ASHRAEASHRAE 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.
Designation
(Safety
Classification)
SNAP Listing Date Listing Status
Evaporative Cooling   N 0 N/A N/A June 16, 2010 (pdf) (229 KB) Acceptable
 RB-276 Free Zone, HCFC Blend Delta R/N 0.013 1,592 A1 September 5, 1996 (pdf) (145 KB) Acceptable
Freeze 12 Freeze 12 R/N 0.013 1,606 A1 September 5, 1996 (pdf) (145 KB) Acceptable
R-414A GHG-X4, HCFC Blend Xi, Autofrost, Chill-it R/N 0.045 1,478 A1 September 5, 1996 (pdf) (145 KB) Acceptable
HFC-134a   R/N 0 1,430 A1 October 1, 2004 (pdf) (186 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-414B Hot Shot, Kar Kool, HCFC Blend Omicron R/N 0.098 3,337 A1 September 5, 1996 (pdf) (145 KB) Acceptable
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 (pdf) (229 KB) Acceptable
R-401C   R/N 0 933 A1 September 5, 1996 (pdf) (145 KB) Acceptable
R-407C Suva 407C, Klea 407C R/N 0 1,770 A1 October 1, 2004 (pdf) (186 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-407F Genetron Performax LT R/N 0 1,820 A1 October 4, 2011 (pdf) (201 KB) Acceptable
R-410A AZ-20, Suva 9100, Puron N 0 2,090 A1 October 1, 2004 (pdf) (186 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-417A ISCEON 59, NU-22 R/N 0 2,350 A1 June 16, 2010 (pdf) (229 KB) Acceptable
R-422B ICOR XAC1, NU-22B R/N 0 2,530 A1 March 29, 2006 (pdf) (181 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-422D ISCEON MO29 R/N 0 2,730 A1 September 28, 2006 (pdf) (183 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-424A RS-44 R/N 0 2,440 A1 January 2, 2009 (pdf) (173 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-426A RS-24 R/N 0 1,510 A1 June 16, 2010 (pdf) (229 KB) Acceptable
R-427A Forane 427A R 0 2,140 A1 January 2, 2009 (pdf) (173 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-434A RS-45 R/N 0 3,250 A1 January 2, 2009 (pdf) (173 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
R-438A KDD5, ISCEON MO99 R/N 0 2,270 A1 October 4, 2007 (pdf) (163 KB);
June 16, 2010 (pdf) (229 KB)
Acceptable
RS-24 (2002 formulation)   R/N 0 1,510 A1 June 16, 2010 (pdf) (229 KB) Acceptable
SP34E SP34E R/N 0 <1,470 A1 June 16, 2010 (pdf) (229 KB) Acceptable
Stirling Cycle   N 0 N/A N/A June 16, 2010 (pdf) (229 KB) Acceptable

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Last updated on May 14, 2025
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