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6560-50-P

EO_12866 SNAP Low GWP Refrigerants 2060-AS04 NPRM 20140508.docx

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82 

[EPA–HQ–OAR–2013–0748; FRL-9906-56-OAR]

RIN: 2060-AS04

Protection of Stratospheric Ozone: Listing of Substitutes for Refrigeration and Air 

Conditioning and Revision of the Venting Prohibition for Certain Refrigerant Substitutes

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

SUMMARY: Pursuant to the U.S. Environmental Protection Agency’s Significant New 

Alternatives Policy program, this action proposes to list a number of flammable refrigerants as 

acceptable substitutes, subject to use conditions, for ozone-depleting substances in several enduses: household refrigerators and freezers, stand-alone commercial refrigerators and freezers, 

very low temperature refrigeration, non-mechanical heat transfer, vending machines, and room 

air conditioning units. This action also proposes to exempt from Clean Air Act Section 608’s 

prohibition on venting, release, or disposal the hydrocarbon refrigerant substitutes that we are 

proposing to list in this action as acceptable subject to use conditions in specific end-uses. We 

are proposing this exemption on the basis of current evidence that their venting, release, or 

disposal would not pose a threat to the environment. 

DATES: Comments must be received on or before [INSERT DATE 60 DAYS AFTER 

PUBLICATION IN FEDERAL REGISTER]. Any party requesting a public hearing must 

notify the contact listed below under FOR FURTHER INFORMATION CONTACT by 5 

p.m. Eastern Daylight Time on [INSERT DATE 15 DAYS AFTER PUBLICATION IN 
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FEDERAL REGISTER]. If a hearing is held, it will take place on or about [INSERT DATE 

30 DAYS AFTER PUBLICATION IN FEDERAL REGISTER] in Washington, DC and 

further information will be provided on EPA’s Stratospheric Ozone Website at 

www.epa.gov/ozone/snap.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA–HQ–OAR–2013–

0748, by one of the following methods:

• www.regulations.gov. Follow the on-line instructions for submitting comments.

• E-mail: A-And-R-Docket@epa.gov.

• Mail: Air and Radiation Docket, Environmental Protection Agency, Mail Code 6102T,

1200 Pennsylvania Ave., NW., Washington, DC 20460, Attention Docket ID No. EPA–HQ–

OAR–2013–0748.

• Hand Delivery: EPA Docket Center, (EPA/DC) EPA West, Room 3334, 1301 

Constitution Ave., NW., Washington, DC, Attention Docket ID No. EPA–HQ–OAR–2013–

0748. Such deliveries are only accepted during the Docket’s normal hours of operation, and 

special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA–HQ–OAR–2013–0748.

EPA’s policy is that all comments received will be included in the public docket without change 

and may be made available online at www.regulations.gov, including any personal information 

provided, unless the comment includes information claimed to be Confidential Business 

Information (CBI) or other information whose disclosure is restricted by statute. Do not submit 

information that you consider to be CBI or otherwise protected through www.regulations.gov or 

e-mail. The www.regulations.gov Website is an “anonymous access” system, which means EPA 

will not know your identity or contact information unless you provide it in the body of your 

comment. If you send an e-mail comment directly to EPA without going through 
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www.regulations.gov, your e-mail address will be automatically captured and included as part of

the comment that is placed in the public docket and made available on the Internet. If you submit 

an electronic comment, EPA recommends that you include your name and other contact 

information in the body of your comment and with any disk or CD–ROM you submit. If EPA 

cannot read your comment due to technical difficulties and cannot contact you for clarification, 

EPA may not be able to consider your comment. Electronic files should avoid the use of special 

characters and any form of encryption, and should be free of any defects or viruses. For 

additional instructions on submitting comments, go to Section I.B. of the SUPPLEMENTARY 

INFORMATION section of this document.

Docket: All documents in the docket are listed in the www.regulations.gov index. 

Although listed in the index, some information is not publicly available, i.e., CBI or other 

information whose disclosure is restricted by statute. Certain other material, such as copyrighted 

material, is not placed on the Internet and will be publicly available only in hard copy form.

Publicly available docket materials are available either electronically in www.regulations.gov or 

in hard copy at the Air and Radiation Docket, EPA/DC, EPA West, Room 3334, 1301

Constitution Ave., NW. Washington, DC. The Public Reading Room is open from 8:30 a.m. to 

4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the

Public Reading Room is (202) 566–1744, and the telephone number for the Air and Radiation 

Docket is (202) 566–1742.

FOR FURTHER INFORMATION CONTACT: Margaret Sheppard, Stratospheric Protection 

Division, Office of Atmospheric Programs, Mail Code 6205J, Environmental Protection Agency, 

1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number (202) 343–9163; fax 

number (202) 343–2338, e-mail address: sheppard.margaret@epa.gov. Notices and rulemakings 

under EPA’s Significant New Alternatives Policy (SNAP) program are available on EPA’s 
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Stratospheric Ozone Website at www.epa.gov/ozone/snap/regs.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information

A. Background

B. Does this action apply to me?

C. What should I consider as I prepare my comments for EPA?

D. What acronyms and abbreviations are used in the preamble?

II. How does the Significant New Alternatives Policy (SNAP) program work?

A. What are the statutory requirements and authority for the SNAP program?

B. What is EPA’s regulation implementing section 612?

C. How do the regulations for the SNAP program work?

D. Where do I find additional information about the SNAP program?

III. What substitutes in what end-uses are considered in this proposed rule?

A. What listing decisions is EPA proposing in this action?

B. What are ethane, isobutane, propane, HFC-32, R-441A, and the ASHRAE 

classifications for refrigerant flammability?

C. What end-uses are included in EPA’s proposed decision?

IV. What criteria did EPA consider in determining whether to list the substitutes as 

acceptable and in determining appropriate use conditions and how does EPA consider 

those factors?

A. Effects on the environment

B. Flammability and fire safety

C. Toxicity

V. Why is EPA proposing these specific use conditions?

A. New equipment only; not intended for use as a retrofit alternative

B. Standards

C. Charge size

D. Color-coded hoses and piping

E. Labeling

F. Other options not included

VI. How is EPA proposing to address venting, release, or disposal of the refrigerant 

substitutes proposed to be listed under section 608 of the Clean Air Act?

A. What are the statutory requirements concerning venting, release, or disposal of 

refrigerants and refrigerant substitutes under section 608 of the Clean Air Act?

B. What are EPA’s regulations concerning venting, releasing or disposing of 

refrigerant substitutes?

C. What revision to the venting prohibition has EPA recently proposed?

D. What is EPA’s proposed determination regarding whether venting of 

hydrocarbons to be listed as acceptable subject to use conditions in the end-uses 

proposed in this NPRM poses a threat to the environment? 

E. What is EPA proposing regarding venting, release, or disposal of refrigerant 

substitutes, other than hydrocarbons, included in our proposed decision?

VII. What recommendations does EPA have for safe use of the proposed flammable substitute 

refrigerants?
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VIII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 

13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act 

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments

G. Executive Order 13045: Protection of Children from Environmental Health and 

Safety Risks

H. Executive Order 13211: Actions that Significantly Affect Energy Supply, 

Distribution, or Use 

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations

IX. References

I. General Information

A. Background

This rule lists as acceptable subject to use conditions a number of flammable refrigerant

substitutes that EPA believes present overall lower risk to human health and the environment 

compared to other available or potentially available alternatives in the same end-uses. The 

proposed refrigerants include one hydrofluorocarbon (HFC) refrigerant—HFC-32—and four

hydrocarbon refrigerants—ethane, isobutane, propane, and R-441A. This proposed rule, if 

finalized as proposed, would list one or more of these substitutes as acceptable subject to use 

conditions in a number of stationary air-conditioning and refrigeration end-uses under the SNAP 

program, including: household refrigerators and freezers, retail food refrigeration, very low 

temperature refrigeration, non-mechanical heat transfer, vending machines, and residential and 

light commercial air conditioning and heat pumps. The use conditions would set requirements to 

ensure that these substitutes do not present significantly greater risk in the end-use than other 

substitutes that are currently or potentially available.

All of the end-uses proposed in this rule are for stationary refrigeration or air 
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conditioning; EPA previously addressed flammable refrigerants in motor vehicle air conditioning 

(MVAC). On June 13, 1995, at 60 FR 31092, the Agency found all flammable substitutes to be 

unacceptable for use in MVAC unless specifically listed as acceptable subject to use conditions 

because of flammability risks and the lack of sufficient risk assessment and sufficient 

information to demonstrate safe use in that end-use at that time. 40 CFR Part 82, Subpart G, 

Appendix B. Some of these risks are unique to motor vehicles. In recent years, EPA has listed 

three low global warming potential (GWP) refrigerants as acceptable subject to use conditions 

for motor vehicles (i.e., R-152a, R-1234yf, and R-744). Two of these refrigerants are flammable, 

although less flammable than hydrocarbons. Under 40 CFR Part 82, Subpart G, Appendix B, all 

other flammable substitutes remain unacceptable for use in motor vehicle air conditioning 

because EPA has not taken action to specifically list them as acceptable subject to use 

conditions.

This proposed rule responds to a number of SNAP submissions for four hydrocarbon 

refrigerants and HFC-32 and also lists some of these refrigerants as acceptable subject to use 

conditions in the same end-uses. Additionally, this action proposes to exempt from Section 608’s 

prohibition on venting, release, or disposal, the four hydrocarbon refrigerant substitutes that we 

are proposing to list as acceptable subject to use conditions in specific end-uses, on the basis of 

current evidence that their venting, release, or disposal does not pose a threat to the environment.

Note that other environmental regulatory requirements still apply. For example, for those 

refrigerants that are volatile organic compounds (VOC) as defined in 40 CFR 50.100(s), i.e., 

isobutane, propane, and R-441A,1a State might adopt additional control strategies if necessary

for an ozone nonattainment area to attain the National Ambient Air Quality Standard (NAAQS) 

for ozone.

With the exception of HFC-32, the refrigerants proposed acceptable subject to use 

 

1 Both ethane and HFC-32 are not VOC under the definition at 40 CFR 51.100(s).
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conditions in this action are hydrocarbons or blends consisting solely of hydrocarbons. 

Hydrocarbon refrigerants have been in use for over 15 years in countries such as Germany, the 

United Kingdom, Australia, and Japan in household and commercial refrigerators and freezers. 

To a lesser extent, hydrocarbon refrigerants have also been used internationally in small air 

conditioning units such as mini-splits and portable room air conditioners. 

Because hydrocarbon refrigerants have zero ozone depletion potential (ODP) and very

low GWPs compared to most other refrigerants, many companies recently have expressed 

interest in using hydrocarbons in the United States. Also, some companies have reported 

improved energy efficiency with hydrocarbon refrigerants (A.S. Trust & Holdings, 2012; A.S. 

Vestfrost, 2012; CHEAA, 2013).

In a final rule in the Federal Register on December 20, 2011 at 76 FR 78832, EPA’s 

SNAP program listed isobutane and R-441A as acceptable subject to use conditions in household 

refrigerators, freezers, and combination refrigerators and freezers and found propane acceptable 

subject to use conditions in retail food refrigerators and freezers (stand-alone units only). In this 

action, EPA is considering isobutane, propane, and R-441A for different end-uses. 

There is interest in use of HFC-32 (difluoromethane, Chemical Abstracts Service 

Registry Number [CAS Reg. No.] 75-10-5) in residential air conditioning systems and heat 

pumps because it has a GWP of 675, which is lower than the GWPs of hydrochlorofluorocarbon 

(HCFC)-22 (1,810) and most other HFC-based refrigerants (approximately 1,500 to 4,000). It 

also has mild flammability compared to hydrocarbon refrigerants. Mini-split systems using HFC32 are now being sold in Japan and are being introduced in India and Indonesia. 

This action proposes to list one or more of these five lower-GWP refrigerant substitute 

options as acceptable subject to use conditions in the end-uses identified previously. This is a 

regular update to EPA’s lists of acceptable substitutes through the SNAP program under the 
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authority of Section 612 of the Clean Air Act. 

This action also responds to a call in the Climate Action Plan announced June 2013 for 

EPA to “use its authority through the Significant New Alternatives Policy Program to encourage 

private sector investment in low-emissions technology by identifying and approving climatefriendly chemicals” (Climate Action Plan, 2013). This rule proposes to approve a number of 

climate-friendly alternatives for various kinds of refrigeration and air conditioning equipment, as 

discussed below. This is the first listing action EPA has taken since the Climate Action Plan was 

issued.

This action, if finalized, would expand the menu of available climate-friendly

alternatives. Many of these alternatives can substitute both for ozone-depleting substances and 

for high-GWP HFCs. Using low-GWP alternatives instead of high-GWP HFCs would reduce the 

impact of climate-damaging emissions. Use and emissions of HFCs is rapidly increasing because 

they are the primary substitutes for ozone-depleting substances in many of the largest end-uses,

and because use is growing worldwide, mostly due to increased demand for refrigeration and air 

conditioning, particularly in developing countries. Though they represent a small fraction of 

current total greenhouse gas (GHG) emissions, their warming impact is hundreds to thousands of 

times higher than that of CO2 and other GHGs and their emissions are projected to increase

significantly over the next several decades, if left unregulated. In the United States, emissions of 

HFCs are expected to double from current levels of 1.5 percent of greenhouse gas emissions to 3 

percent by 2020 and nearly triple by 20302.

HFCs are rapidly accumulating in the atmosphere. For example, the atmospheric 

concentration of HFC-134a, the most abundant HFC, has increased by about 10% per year from 

2006 to 2012, and concentrations of HFC-143a and HFC-125 have risen over 13% and 16% per 

 

2

Climate Change and President Obama’s Action Plan. June, 2013. Available online at 

www.whitehouse.gov/share/climate-action-plan
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year from 2007-2011, respectively (Montzka, 2012; NOAA, 2013). 

This action proposes to find acceptable, for specific end-uses and subject to use 

conditions, several alternatives that have GWPs significantly lower than both the ozonedepleting substances (ODS) and HFC substitute refrigerants currently used in those end-uses. For 

example, this action, if finalized, would allow the use of isobutane (R-600a) and the hydrocarbon 

blend R-441A in stand-alone commercial refrigerators. The GWPs3of these hydrocarbon 

refrigerants are less than 10, while HFCs typically used in this end-use—HFC-134a and R-404A 

(a blend of three HFCs)—have GWPs of 1,430 and approximately 3,920, respectively. In 

addition, this action proposes to find propane (R-290) acceptable for use in household 

refrigerator-freezers, subject to use conditions. The GWP of R-290 is 3.3 compared to the GWP 

of 1430 for HFC-134a, which is typically used in such equipment at the present time in the U.S. 

Finally, this action, if finalized, would allow for the use of propane, R-441A, and 

difluoromethane (HFC-32) in stand-alone room air conditioners. These alternatives have GWPs 

of 675 or less and could replace the use of R-410A (a blend of two HFCs), which has a GWP of 

approximately 2,090. ODS replaced in the end-uses in this rule include chlorofluorocarbon 

(CFC)-12 (ODP4of 1 and GWP of 10,900), R-13B1 (also known as bromotrifluoromethane or 

halon 1301, with ODP of 10 and GWP of 7,140), CFC-113 (ODP of 0.8 and GWP of 6,130), R502 (a blend of CFC-115 and HCFC-22, with ODP of 0.334 and GWP of 4,660), and HCFC-22 

 

3 GWPs for HFC-134a, HFC-32, the component HFCs comprising R-404A and R-410A, propane and ethane are 

listed in IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the 

Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, 

Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, 

United Kingdom and New York, NY, USA. This document is accessible at 

www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html. GWPs for isobutane and R-441A were provided by 

the submitters to EPA and they are consistent with available information for their components and the range of 

GWPs found for other hydrocarbons in IPCC, 2007. For refrigerant blends, EPA has taken the 100-year integrated 

time horizon GWP from IPCC, 2007 for the component compounds and multiplied them by the weight fraction of 

each component in the blend to obtain an approximate GWP. Unless otherwise stated, GWPs stated in this document 

are 100-year integrated time horizon values taken from IPCC, 2007.

4 Unless otherwise stated, the ODP values used in this document are those published in appendices A and B to 

subpart A of 40 CFR part 82. For refrigerant blends, EPA has taken the ODPs for the component compounds and 

multiplied them by the weight fraction of each component in the blend to obtain an approximate ODP.
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(ODP of 0.055 and GWP of 1,810).

B. Does this action apply to me?

This notice of proposed rulemaking (NPRM) would list the following flammable 

refrigerants as acceptable subject to use conditions for use in specific end-uses within the 

refrigeration and air conditioning sector: ethane (R-170), HFC-32 (R-32), isobutane (R-600a), 

propane (R-290), and the hydrocarbon blend R-441A. Types of residential and light commercial 

air conditioning equipment addressed in this NPRM include window AC units; packaged 

terminal AC units and heat pumps; and portable room AC units. Types of refrigeration 

equipment include stand-alone commercial refrigerators and freezers (retail food refrigeration), 

very low temperature freezers, thermosiphons (non-mechanical transfer equipment), household 

refrigerators and freezers, and vending machines.

Table 1 identifies the potential entities that may wish to use ethane, HFC-32, R-441A, 

isobutane, propane, and other flammable refrigerants in these end-uses. 

TABLE 1—POTENTIALLY REGULATED ENTITIES BY NORTH AMERICAN 

INDUSTRIAL CLASSIFICATION SYSTEM (NAICS) CODE OR SUBSECTOR

Category NAICS code 

or subsector Description of regulated entities

Industry 325412 Pharmaceutical Preparations (e.g., Capsules, 

Liniments, Ointments, Tablets) Manufacturing

Industry 333415 Manufacturers of Refrigerators, Freezers, and Other 

Refrigerating or Freezing Equipment, Electric or 

Other; Heat Pumps Not Elsewhere Specified or 

Included (NESOI); and Parts Thereof

Industry 443111 Appliance Stores: Household-type

Industry 445120 Convenience Stores

Industry 445110 Supermarkets and Other Grocery (except 

Convenience) Stores

Industry 722211 Limited-Service Restaurants

Industry 238220 Plumbing, Heating, and Air Conditioning 

Contractors

Industry 811412 Appliance Repair and Maintenance 

Industry 423620 Household Appliances, Electric Housewares, and 

Consumer Electronics Merchant Wholesalers

Industry 423740 Refrigeration Equipment and Supplies Merchant 

Wholesalers
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This table is not intended to be exhaustive, but rather a guide regarding entities likely to 

adopt the substitutes whose use would be regulated by this proposed action. If you have any

questions about whether this action applies to a particular entity, consult the person listed in the 

preceding section, FOR FURTHER INFORMATION CONTACT.

C. What should I consider as I prepare my comments for EPA?

1. Submitting Confidential Business Information (CBI)

Do not submit confidential information to EPA through www.regulations.gov or e-mail. 

Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a 

disk or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as CBI and 

then identify electronically within the disk or CD-ROM the specific information that is claimed 

as CBI. In addition to one complete version of the comment that includes information claimed as 

CBI, a copy of the comment that does not contain the information claimed as CBI must be 

submitted for inclusion in the public docket. Information marked as CBI will not be disclosed 

except in accordance with procedures set forth in 40 Code of Federal Regulations (CFR) Part 2.

2. Tips for preparing your comments

When submitting comments, remember to:

 Identify the rulemaking by docket number and other identifying information (subject 

heading, Federal Register date, and page number).

 Follow directions. The agency may ask you to respond to specific questions or organize 

comments by referencing a CFR part or section number.

 Explain why you agree or disagree; suggest alternatives and substitute language for 

your requested changes.
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 Describe any assumptions and provide any technical information and/or data that you 

used.

 If you estimate potential costs or burdens, explain how you arrived at your estimate in 

sufficient detail to allow for it to be reproduced.

 Provide specific examples to illustrate your concerns, and suggest alternatives.

 Explain your views as clearly as possible, avoiding the use of profanity or personal 

threats.

 Make sure to submit your comments by the comment period deadline identified.

D. What acronyms and abbreviations are used in the preamble?

Below is a list of acronyms and abbreviations used in this preamble.

AC—air conditioning

ACGIH—American Conference of Governmental Industrial Hygienists

ACH—air changes per hour 

AEGL—acute exposure guideline level 

AHRI—Air Conditioning, Heating and Refrigeration Institute

ANSI—American National Standards Institute

ASHRAE—American Society of Heating, Refrigerating and Air-Conditioning Engineers

BTU—British thermal unit

CAA—Clean Air Act 

CAS Reg. No.—Chemical Abstracts Service Registry Identification Number 

CBI—Confidential Business Information 

CFC—chlorofluorocarbon

CFR—Code of Federal Regulations 

CMAQ—Community Multiscale Air Quality
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DOE—the United States Department of Energy

EO—Executive Order

EPA—the United States Environmental Protection Agency

FR—Federal Register

GHG—greenhouse gas

GWP—global warming potential 

HCFC—hydrochlorofluorocarbon 

HFC—hydrofluorocarbon

ICF—ICF International, Inc.

ICR—Information Collection Request 

IEC—International Electrotechnical Commission

IPCC—Intergovernmental Panel on Climate Change

IPR—industrial process refrigeration

kJ—kilojoule

kPa—kilopascal

lb—pound

LFL—lower flammability limit 

MSDS—Material Safety Data Sheet 

MVAC—motor vehicle air conditioning

NAAQS—National Ambient Air Quality Standard

NAICS—North American Industrial Classification System

NIOSH—the United States National Institute for Occupational Safety and Health 

NOAEL—No Observed Adverse Effect Level

NPRM—Notice of Proposed Rulemaking 
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NTTAA—National Technology Transfer and Advancement Act

OEM—original equipment manufacturer 

ODP—ozone depletion potential 

ODS—ozone-depleting substance 

OHA—Office of Hearing and Appeals

OMB—the United States Office of Management and Budget

OSHA—the United States Occupational Safety and Health Administration 

PEL—permissible exposure limit 

PFC—perfluorocarbon

PMS—Pantone Matching System

ppb—parts per billion 

ppm—parts per million 

PRA—Paperwork Reduction Act

PTAC—packaged terminal air conditioner

PTHP—packaged terminal heat pump

REL—recommended exposure limit 

RFA—Regulatory Flexibility Act 

SBA—the United States Small Business Administration 

SNAP—Significant New Alternatives Policy

STEL—short term exposure limit

TLV—threshold limit value

TSCA—Toxic Substances Control Act 

TWA—time-weighted average 

UL—Underwriters Laboratories Inc. 
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UMRA—Unfunded Mandates Reform Act

VOC—volatile organic compounds

II. How does the Significant New Alternatives Policy (SNAP) program work?

A. What are the statutory requirements and authority for the SNAP Program?

Section 612 of the Clean Air Act (CAA) requires EPA to develop a program for 

evaluating alternatives to ozone-depleting substances (ODS). EPA refers to this program as the 

Significant New Alternatives Policy (SNAP) program. The major provisions of section 612 are

the following: 

1. Rulemaking

Section 612(c) requires EPA to promulgate rules making it unlawful to replace any class I 

substance (chlorofluorocarbon, halon, carbon tetrachloride, methyl chloroform, and 

hydrobromofluorocarbon) or class II substance (hydrochlorofluorocarbon) with any substitute 

that the Administrator determines may present adverse effects to human health or the 

environment where the Administrator has identified an alternative that (1) reduces the overall 

risk to human health and the environment and (2) is currently or potentially available.

2. Listing of Unacceptable/Acceptable Substitutes

Section 612(c) requires EPA to publish a list of the substitutes unacceptable for specific 

uses and to publish a corresponding list of acceptable alternatives for specific uses. The list of 

acceptable substitutes may be found at www.epa.gov/ozone/snap/lists, and the lists of 

“unacceptable,” “acceptable subject to use conditions,” and “acceptable subject to narrowed use 

limits” substitutes are found in the appendices to Subpart G of 40 CFR Part 82 as well as at 

www.epa.gov/ozone/snap/lists. 

3. Petition Process

Section 612(d) grants the right to any person to petition EPA to add a substance to, or 

delete a substance from, the lists published in accordance with section 612(c). The Agency has 
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90 days to grant or deny a petition. Where the Agency grants the petition, EPA must publish the 

revised lists within an additional six months.

4. 90-day Notification

Section 612(e) directs EPA to require any person who produces a chemical substitute for 

a class I substance to notify the Agency not less than 90 days before new or existing chemicals 

are introduced into interstate commerce for significant new uses as substitutes for a class I 

substance. The producer must also provide the Agency with the producer's unpublished health 

and safety studies on such substitutes.

5. Outreach

Section 612(b)(1) states that the Administrator shall seek to maximize the use of federal 

research facilities and resources to assist users of class I and II substances in identifying and 

developing alternatives to the use of such substances in key commercial applications.

6. Clearinghouse

Section 612(b)(4) requires the Agency to set up a public clearinghouse of alternative 

chemicals, product substitutes, and alternative manufacturing processes that are available for 

products and manufacturing processes which use class I and II substances.

B. What is EPA’s regulation implementing section 612?

On March 18, 1994, EPA published the original rulemaking (59 FR 13044) which 

established the process for administering the SNAP program and issued EPA's first lists 

identifying acceptable and unacceptable substitutes in the major industrial use sectors (Subpart G 

of 40 CFR Part 82). These eight sectors - refrigeration and air conditioning; foam blowing; 

cleaning solvents; fire suppression and explosion protection; sterilants; aerosols; adhesives, 

coatings and inks; and tobacco expansion - are the principal industrial sectors that historically

consumed the largest volumes of ODS.
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Section 612 of the CAA instructs EPA to list as acceptable those substitutes that present a 

lower overall risk to human health and the environment as compared with other substitutes that 

are currently or potentially available for a specific use. 

C. How do the regulations for the SNAP program work?

Under the SNAP regulations, anyone who plans to market or produce a substitute in one 

of the eight major industrial use sectors where class I or class II substances have been used must 

provide notice to the Agency, including health and safety information on the substitute, at least 

90 days before introducing it into interstate commerce for significant new use as an alternative. 

40 CFR 82.176(a). This requirement applies to the persons planning to introduce the substitute 

into interstate commerce,5 who typically are chemical manufacturers but may include importers, 

formulators, equipment manufacturers, and end users when they are responsible for introducing a 

substitute into commerce.6The CAA and the SNAP regulations, 40 CFR 82.174(a), prohibit use 

of a substitute earlier than 90 days after notice has been provided to the Agency. EPA considers 

that notice has been received once EPA receives the submission and determines that the 

submission includes complete and adequate data. 40 CFR 82.180(a). At that point, the SNAP 

review begins. 

The Agency has identified four possible decision categories for substitutes that are 

submitted for evaluation: acceptable; acceptable subject to use conditions; acceptable subject to 

narrowed use limits; and unacceptable7(40 CFR 82.180(b)). Use conditions and narrowed use 

 

5 As defined at 40 CFR 82.104, “interstate commerce” means the distribution or transportation of any product 

between one state, territory, possession or the District of Columbia, and another state, territory, possession or the 

District of Columbia, or the sale, use or manufacture of any product in more than one state, territory, possession or 

District of Columbia. The entry points for which a product is introduced into interstate commerce are the release of a 

product from the facility in which the product was manufactured, the entry into a warehouse from which the 

domestic manufacturer releases the product for sale or distribution, and at the site of United States Customs 

clearance.

6 As defined at 40 CFR 82.172, “end-use” means processes or classes of specific applications within major industrial 

sectors where a substitute is used to replace an ODS. 

7 The SNAP regulations also include “pending,” referring to submissions for which EPA has not reached a 

determination under this provision.
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limits are both considered “use restrictions” and are explained below. Substitutes that are deemed 

acceptable with no use restrictions (no use conditions or narrowed use limits) can be used for all 

applications in the relevant end-uses within the sector. Substitutes that are acceptable subject to 

use restrictions may be used only in accordance with those restrictions.

After reviewing a substitute, the Agency may make a determination that a substitute is 

acceptable only if certain conditions are met in the way that the substitute is used to minimize 

risks to human health and the environment. EPA describes such substitutes as “acceptable 

subject to use conditions.” Entities that use these substitutes without meeting the associated use 

conditions are in violation of section 612 of the CAA and EPA’s SNAP regulations. 40 CFR 

82.174(c).

For some substitutes, the Agency may permit a narrowed range of use within an end-use

or sector. For example, the Agency may limit the use of a substitute to certain end-uses or 

specific applications within an industry sector. EPA describes these substitutes as “acceptable 

subject to narrowed use limits.” A person using a substitute that is acceptable subject to 

narrowed use limits in applications and end-uses that are not consistent with the narrowed use 

limit is using the substitute in an unacceptable manner and is in violation of section 612 of the 

CAA and EPA’s SNAP regulations. 40 CFR 82.174(c).

The Agency publishes its SNAP program decisions in the Federal Register (FR). EPA 

publishes proposed decisions concerning substitutes that are deemed acceptable subject to use 

restrictions (use conditions and/or narrowed use limits), or substitutes deemed unacceptable, as 

proposed rulemakings to provide the public providing an opportunity to comment, before 

publishing final decisions.

In contrast, EPA publishes decisions concerning substitutes that are deemed acceptable 

with no restrictions as “notices of acceptability” or “determinations of acceptability,” rather than 
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as proposed and final rules. As described in the preamble to the rule initially implementing the 

SNAP program in the Federal Register at 59 FR 13044 on March 18, 1994, EPA does not believe 

that rulemaking procedures are necessary to list alternatives that are acceptable without 

restrictions because such listings neither impose any sanction nor prevent anyone from using a 

substitute.

Many SNAP listings include “Comments” or “Further Information” to provide additional 

information on substitutes. Since this additional information is not part of the regulatory 

decision, these statements are not binding for use of the substitute under the SNAP program. 

However, regulatory requirements so listed are binding under other regulatory programs (e.g., 

worker protection regulations promulgated by the Occupational Safety and Health 

Administration (OSHA)). The “Further Information” identified in the listing does not necessarily

include all other legal obligations pertaining to the use of the substitute. While the items listed 

are not legally binding under the SNAP program, EPA encourages users of substitutes to apply

all statements in the “Further Information” column in their use of these substitutes. In many 

instances, the information simply refers to sound operating practices that have already been 

identified in existing industry and/or building codes or standards. Thus many of the statements, if 

adopted, would not require the affected user to make significant changes in existing operating 

practices.

D. Where do I find additional information about the SNAP program?

For copies of the comprehensive SNAP lists of substitutes or additional information on 

SNAP, refer to EPA’s Ozone Depletion website at: www.epa.gov/ozone/snap. For more 

information on the Agency's process for administering the SNAP program or criteria for 

evaluation of substitutes, refer to the SNAP final rulemaking in the Federal Register at 59 FR 

13044 on March 18, 1994, codified at 40 CFR Part 82, Subpart G. A complete chronology of 
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SNAP decisions and the appropriate citations is found at: www.epa.gov/ozone/snap/chron.html.

III. What substitutes in what end-uses are considered in this proposed rule?

A. What listing decisions is EPA proposing in this action?

In this action, EPA proposes to list the following refrigerants as acceptable substitutes, 

subject to use conditions, in the identified end-uses.

1. Retail food refrigeration. EPA proposes to list isobutane (also referred to as R–600a) and 

the hydrocarbon blend R-441A as acceptable subject to use conditions as substitutes in retail 

food refrigeration (new stand-alone commercial refrigerators and freezers only). EPA proposes 

the following use conditions:

i. The quantity of the substitute refrigerant (i.e., “charge size”) must not exceed 150 grams 

(5.29 ounces);

ii. These refrigerants may be used only in new equipment designed specifically and clearly 

identified for the refrigerant--i.e., none of these substitutes may be used as a conversion or 

“retrofit”

8

refrigerant for existing equipment;

iii. These refrigerants may be used only in stand-alone commercial refrigerators and freezers 

that meet all requirements listed in Supplement SB to the 10th edition of Underwriters 

Laboratories (UL) Standard 471, dated November 24, 2010. In cases where the proposed rule 

includes requirements more stringent than those of the 10th edition of UL Standard 471, the 

appliance must meet the requirements of the rule, as finalized;

iv. The refrigerator or freezer must have red Pantone Matching System (PMS) #185 marked 

pipes, hoses, or other devices through which the refrigerant passes, to indicate the use of a 

flammable refrigerant. This color must be applied at all service ports and other parts of the 

system where service puncturing or other actions creating an opening from the refrigerant circuit 

to the atmosphere might be expected and must extend a minimum of one (1) inch in both 

 

8

Sometimes conversion refrigerant substitutes are inaccurately referred to as “drop in” replacements.
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directions from such locations;

v. The following markings, or the equivalent, must be provided and must be permanent:

(a) “DANGER—Risk of Fire or Explosion. Flammable Refrigerant Used. Do Not 

Use Mechanical Devices To Defrost Refrigerator. Do Not Puncture Refrigerant Tubing.” This 

marking must be provided on or near any evaporators that can be contacted by the consumer.

(b) “DANGER—Risk of Fire or Explosion. Flammable Refrigerant Used. To Be 

Repaired Only By Trained Service Personnel. Do Not Puncture Refrigerant Tubing.” This 

marking must be located near the machine compartment.

(c) “CAUTION—Risk of Fire or Explosion. Flammable Refrigerant Used. Consult 

Repair Manual/Owner’s Guide Before Attempting To Service This Product. All Safety

Precautions Must be Followed.” This marking must be located near the machine compartment.

(d) “CAUTION—Risk of Fire or Explosion. Dispose of Properly In Accordance With 

Federal Or Local Regulations. Flammable Refrigerant Used.” This marking must be provided on 

the exterior of the refrigeration equipment.

(e) “CAUTION—Risk of Fire or Explosion Due To Puncture Of Refrigerant Tubing; 

Follow Handling Instructions Carefully. Flammable Refrigerant Used.” This marking must be 

provided near all exposed refrigerant tubing.

With regard to the proposed use conditions, we note the following. First, regarding the 

use of red marking for pipes, hoses and other devices in proposed use condition iv, we discuss 

and solicit comment on direct color application on the applicable parts of the system, such as a 

red plastic sleeve, in Section V.D, “Color-coded hoses and piping.” Discussion of application of 

red coloring for equipment utilizing a process tube is also provided there. Second, regarding 

proposed use condition v., the difference between this proposed requirement and clauses SB6.1.2 

to SB6.1.5 of UL Standard 471 is that all of these markings must be in letters no less than 6.4 
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mm (1⁄4 inch) high. In UL 471, the markings are required to be no less than 3.2 mm (1/8 inch) 

high.

2. Very low temperature refrigeration and non-mechanical heat transfer. EPA proposes to list 

ethane (also referred to as R-170), as acceptable, subject to use conditions, in very low 

temperature refrigeration equipment and in non-mechanical heat transfer, subject to the same use 

conditions as described above for isobutane and R-441A in stand-alone commercial refrigerators 

and freezers.

3. Household refrigerators and freezers. EPA proposes to list propane (also referred to as R–

290), as acceptable subject to use conditions as a substitute in household refrigerators and 

freezers and combination refrigerator/freezers subject to the following use conditions. 

i. The charge size for any household refrigerator, freezer, or combination refrigerator and 

freezer for each circuit using R–290 must not exceed 57 grams (2.01 ounces);

ii. This refrigerant may be used only in new equipment specifically designed and clearly

identified for the refrigerant--i.e., none of these substitutes may be used as a conversion or 

“retrofit” refrigerant for existing equipment;

iii. This substitute may be used only in equipment that meets all requirements in Supplement 

SA to the 10th edition of UL Standard 250, dated August 25, 2000. (In cases where the proposed 

rule includes requirements more stringent than those of the 10th edition of UL Standard 250, the 

appliance must meet the requirements of the final SNAP listing);

iv. The refrigerator or freezer must have red Pantone Matching System (PMS) #185 marked

pipes, hoses, and other devices through which the refrigerant passes to indicate the use of a 

flammable refrigerant;

v. Permanent markings must be provided on the equipment, as described above for standalone commercial refrigerators and freezers. All of these markings must be in letters no less than 
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6.4 mm (1⁄4 inch) high. (The difference between this requirement and clauses SA6.2.1 to 

SA6.2.5 of UL Standard 250 is that in UL 250, the markings are required to be no less than 3.2 

mm [1/8 inch] high instead of 6.4 mm [1/4 inch]).

4. Vending machines. EPA proposes to list R–441A, isobutane and propane as acceptable 

substitutes in vending machines, subject to the same use conditions described above for standalone commercial refrigerators and freezers, except that paragraph iii. would read as follows:

Equipment must meet all requirements of Supplement SA to the 7th edition of UL 

Standard 541, “Refrigerated Vending Machines,” dated December 30, 2011 (instead of the 10th 

edition of UL 471).

Note that in UL 541, the relevant references on equipment markings for flammable 

refrigerants in Supplement A are sections SA 6.1.2-SA 6.1.5. 

5. Residential and light commercial air conditioning and heat pumps. EPA proposes to list 

propane (also known as R-290), difluoromethane (also known as HFC-32 or R-32), and R-441A

as acceptable subject to use conditions as substitutes in residential and light commercial air 

conditioning for self-contained room air conditioners, including packaged terminal air 

conditioners (PTACs) and packaged terminal heat pumps (PTHPs), window AC units, and 

portable AC units designed for use in a single room.

9 EPA proposes the following use 

conditions:

i. These refrigerants may be used only in new equipment designed specifically and clearly

identified for the refrigerant--i.e., none of these substitutes may be used as a conversion or 

“retrofit” refrigerant for existing equipment;

ii. These refrigerants may be used only in air conditioners that meet all requirements listed 

in Supplement SA to the 8th edition, dated August 2, 2012, of Underwriters Laboratories (UL) 

 

9

Packaged terminal air conditioners are intended for use in a single room and use no ducts to carry cooled air and no 

external refrigerant lines. Typical applications include motel or dormitory air conditioners. 
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Standard 484, “Room Air Conditioners.” In cases where the final rule includes requirements 

more stringent than those of the 8th edition of UL Standard 484, the appliance must meet the 

requirements of the final rule in place of the requirements in the UL Standard;

iii. UL 484 includes charge limits for room air conditioners and adherence to those charge 

limits would normally be confirmed by the installer. In addition to proposing the charge limits in 

the UL 484 standard as a requirement, EPA is proposing the following charge size limits 

adherence to which must be confirmed by the original equipment manufacturer (OEM). In cases 

where the charge size limit listed is different from those determined by UL 484, the smaller of 

the two charge sizes would apply. For a review of how these charge size limits were derived, see 

“Derivation of Charge Limits for Room Air Conditioners,” EPA, 2013 in the docket. The charge

size limit must be determined based on the type of equipment, the alternative refrigerant used, 

and the normal rated capacity of the unit. The proposed limits are presented in Tables 3 through 

6 below in section V.C, “Charge size,” and in Tables A, B, C and D of the regulatory text at the 

end of this document. 

iv. The air conditioner must have red Pantone Matching System (PMS) #185 marked pipes, 

hoses, or other devices through which the refrigerant passes to indicate the use of a flammable 

refrigerant. This color must be applied at all service ports and other parts of the system where 

service puncturing or other actions creating an opening from the refrigerant circuit to the 

atmosphere might be expected and must extend a minimum of one (1) inch in both directions 

from such locations;

v. The following markings, or the equivalent, must be provided and must be permanent:

(a) On the outside of the air conditioner: “DANGER—Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do Not 

Puncture Refrigerant Tubing.”
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(b) On the outside of the air conditioner: “CAUTION—Risk of Fire or Explosion. 

Dispose of Properly In Accordance With Federal Or Local Regulations. Flammable Refrigerant 

Used.”

(c) On the inside of the air conditioner near the compressor: “CAUTION—Risk of 

Fire or Explosion. Flammable Refrigerant Used. Consult Repair Manual/Owner’s Guide Before 

Attempting To Service This Product. All Safety Precautions Must be Followed.”

(d) For portable air conditioners, packaged terminal air conditioners and packaged 

terminal heat pumps, on the outside of the product: “WARNING: Appliance shall be installed, 

operated and stored in a room with a floor area larger than “X” m2(Y ft2).” The value “X” must 

be determined using the minimum room size in m2calculated using Appendix F of UL 484. The 

evaporator must remain no higher than 0.6 m above the floor.

(e) For window air conditioners, on the outside of the product: “WARNING: 

Appliance shall be installed, operated and stored in a room with a floor area larger than “X” m2

(Y ft2).” The value “X” must be determined using the minimum room size in m2calculated using 

Appendix F of UL 484. The evaporator must remain no higher than 1.06 m above the floor.

All of these markings must be in letters no less than 6.4 mm (1⁄4 inch) high. (The 

difference between this requirement and clauses SA6.2.1 to SA6.2.5 of UL Standard 484 is that 

in UL 484, the markings are required to be no less than 3.2 mm [1/8 inch] high instead of 6.4 

mm [1/4 inch]).

The regulatory text of our proposed decisions appears in tables at the end of this 

document. If finalized as proposed, this text would be codified at 40 CFR Part 82 Subpart G. The 

proposed regulatory text contains listing decisions for the end-uses discussed above. We note 

that there may be other legal obligations pertaining to the manufacture, use, handling, and 

disposal of hydrocarbons that are not included in the information listed in the tables (e.g., section 
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608 prohibition on venting, releasing, or disposing of refrigerant substitutes or Department of 

Transportation requirements for transport of flammable gases).

In summary, EPA is proposing to list ethane, isobutane, propane, HFC-32, and R-441A

as acceptable subject to use conditions as substitute refrigerants in certain refrigeration and air 

conditioning end-uses. If this proposal were to become final, it would be legal to use those 

refrigerants in the specified types of equipment under the conditions identified above. Use in the 

specified types of equipment that is not consistent with the use conditions, as finalized, would be 

a violation of CAA section 612 and EPA’s implementing regulations. Both the equipment 

manufacturers and the end users should be familiar with these proposed use conditions and EPA 

would expect them to comply with any final use conditions.

B. What are ethane, isobutane, propane, HFC-32, R-441A, and the ASHRAE classifications for 

refrigerant flammability?

Ethane, isobutane, and propane are hydrocarbons and R-441A is a hydrocarbon blend. 

Hydrocarbons are highly flammable organic compounds made up of hydrogen and carbon. 

Ethane has two carbons and a chemical formula of C2H6. Propane has three carbons and the 

formula C3H8. Isobutane has four carbons and the formula C4H10, also written as CH(CH3)2CH3

to distinguish it from n-butane. The respective Chemical Abstracts Service Registry Numbers 

(CAS Reg. Nos.) of ethane, propane, and isobutane are 74-84-0, 74–98–6, and 75–28–5. As 

refrigerants, ethane, propane, and isobutane can be referred to by the American Society of 

Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) designations R-170, R–290 

and R–600a, respectively.

R-441A, also known by the trade name “HCR-188C,” is a highly flammable hydrocarbon 

blend consisting of 55% propane, 36% n-butane, 6% isobutane, and 3% ethane by weight. HFC32 is a mildly flammable organic compound made up of hydrogen, carbon, and fluorine with the 
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chemical formula CF2H2 (CAS Reg. No. 75-10-5).

The American National Standards Institute (ANSI)/ASHRAE Standard 34–2010 assigns 

a safety group classification for each refrigerant which consists of two alphanumeric characters 

(e.g., A2 or B1). The capital letter indicates the toxicity and the numeral denotes the 

flammability. ASHRAE classifies Class A refrigerants as refrigerants for which toxicity has not 

been identified at concentrations less than or equal to 400 parts per million (ppm) by volume, 

based on data used to determine threshold limit value-time-weighted average (TLV–TWA) or 

consistent indices. Class B signifies refrigerants for which there is evidence of toxicity at 

concentrations below 400 ppm by volume, based on data used to determine TLV–TWA or 

consistent indices. The refrigerants are also assigned a flammability classification of 1, 2, or 3.

Tests are conducted in accordance with ASTM E681 using a spark ignition source at 60 °C and 

101.3 kPa (ASHRAE, 2010). Figure 1 in ANSI/ASHRAE Standard 15–2007 uses the same 

safety group but limits its concentration to 3400 ppm.

The flammability classification “1” is given to refrigerants that, when tested, show no 

flame propagation. The flammability classification “2” is given to refrigerants that, when tested, 

exhibit flame propagation, have a heat of combustion less than 19,000 kJ/kg (8,174 BTU/lb), and 

have a lower flammability limit (LFL) greater than 0.10 kg/m3. Refrigerants within flammability

classification 2 may optionally be designated in the lower flammability subclass “2L” if they

have a maximum burning velocity of 10 cm/s or lower when tested at 23.0 °C and 101.3 kPa.

The flammability classification “3” is given to refrigerants that, when tested, exhibit flame 

propagation and that either have a heat of combustion of 19,000 kJ/kg (8,174 BTU/lb) or greater 

or an LFL of 0.10 kg/m3or lower. For both toxicity and flammability classifications, refrigerant 

blends are designated based on the worst case of fractionation determined for the blend (which 

may be different when evaluating toxicity than when evaluating flammability).
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Figure 1. Refrigerant Safety Group Classification

Safety Group

In

cre

asin

g

Fla

m

m

ability

Higher 

Flammability

A3 B3

Lower 

Flammability

A2 B2

A2L B2L

No Flame 

Propagation

A1 B1

Lower 

Toxicity

Higher 

Toxicity

Increasing Toxicity

Using these safety group classifications, ANSI/ASHRAE Standard 34–2010 categorizes 

ethane, isobutane, propane, and R-441A in the A3 Safety Group and categorizes HFC-32 in the 

A2L Safety Group.

C. What end-uses are included in our proposed decision?

1. Household Refrigerators, Freezers, and Combination Refrigerator/Freezers

Household refrigerators, freezers, and combination refrigerator/freezers are intended 

primarily for residential use, although they may be used outside the home. Household freezers

only offer storage space at freezing temperatures, unlike household refrigerators. Products with 

both a refrigerator and freezer in a single unit are most common. Wine coolers used in residential 

settings are considered part of this end-use. EPA previously found the flammable hydrocarbon 

refrigerants isobutane and R-441A acceptable subject to use conditions in this end-use. 

December 20, 2011, at 76 FR 78832, codified at Appendix R of Subpart G of 40 CFR Part 82.

2. Retail Food Refrigeration--Stand-Alone Commercial Refrigerators and Freezers

Retail food refrigeration includes the refrigeration systems, including cold storage cases, 

designed to chill food or keep it at a cold temperature for commercial sale. In this proposed rule, 

we are considering the use of hydrocarbons only in stand-alone equipment. A stand-alone 

appliance is one utilizing a sealed hermetic compressor and for which all refrigerant-containing 
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components, including but not limited to the compressor, condenser, and evaporator, are 

assembled into a single piece of equipment before delivery to the ultimate consumer or user.

Such equipment does not require the addition or removal of refrigerant when placed into initial 

operation. Stand-alone equipment is used to chill or to store chilled beverages or frozen products

(e.g., reach-in beverage coolers, stand-alone ice cream cabinets, and wine coolers in commercial 

settings). This proposed rule does not apply to large commercial refrigeration systems such as, 

but not limited to, multiplex direct expansion refrigeration systems typically found in

supermarkets. Such equipment typically requires larger charge sizes than those considered in this 

proposed rule. This proposal also does not apply to walk-in coolers, a type of equipment that 

typically requires larger charges than those considered in this proposed rule. EPA has already 

listed propane as acceptable subject to use conditions for use in stand-alone commercial 

refrigerators and freezers. December 20, 2011, at 76 FR 78832, codified at Appendix R to 

Subpart G of 40 CFR Part 82.

3. and 4. Very low temperature refrigeration and non-mechanical heat transfer equipment. 

Very low temperature refrigeration equipment is intended to maintain temperatures 

considerably lower than for refrigeration of food—for example, -80 °C (-170 °F) or lower. 

Examples of very low temperature refrigeration equipment include medical freezers and freezedryers, which generally require extremely reliable refrigeration cycles to maintain low 

temperatures and must meet stringent technical standards. In some cases, very low temperature 

refrigeration equipment may use a refrigeration system with two refrigerant loops or with a direct 

expansion refrigeration loop coupled with an alternative refrigeration technology (e.g., Stirling 

cycle). This allows a greater range of temperatures and may reduce the overall refrigerant charge.

There is no U.S. standard that we are aware of that applies specifically to very low 

temperature refrigeration or non-mechanical heat transfer. The submitter of information for use 
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of ethane in very low temperature refrigeration has indicated that Underwriters Laboratories, Inc.

will test their equipment for compliance with the UL 471 standard for commercial refrigeration 

equipment, which addresses stand-alone commercial refrigerators and freezers. We are proposing 

compliance with the UL 471 standard as one of the conditions for use of ethane in very low 

temperature refrigeration equipment. This submission also addressed the use of ethane in a type 

of non-mechanical heat transfer equipment called a thermosiphon. Non-mechanical heat transfer 

involves cooling systems that rely on convection to remove heat from an area, rather than 

mechanical refrigeration. A thermosiphon is a type of heat transfer system that relies on natural 

convection currents, as opposed to using a mechanical pump. This proposal would allow use of 

ethane in non-mechanical heat transfer uses, provided that they meet the use conditions, 

including the requirements of Supplement B to the UL 471 standard and a charge limit of 150 

g.10

5. Vending Machines

Vending machines are self-contained units for refrigerating beverages or food which 

dispense goods that must be kept cold or frozen. This end-use differs from other retail food 

refrigeration because goods are dispensed, rather than allowing the consumer to reach in to grab 

a beverage or food product. The design of the refrigeration system of a vending machine is 

similar to that of a self-contained commercial refrigerator or freezer. Typically the difference lies 

in how payment for goods is made and in the selection mechanisms found in vending machines 

but not in self-contained commercial refrigerator-freezers, and possibly the outer casing (e.g., 

glass doors and open, reach-in designs are generally used in self-contained commercial 

refrigerator-freezers whereas glass wall and other types of casings are used for vending 

machines). The standard UL 541 applies to vending machines. It contains a Supplement SA 

 

10 EPA expects that equipment designed for cooling the engine compartment of heavy duty vehicles, a potential nonmechanical heat transfer application, does not meet the requirements of UL 471 and thus, would not meet the 

requirements of this rule. Similar issues may exist for some other non-mechanical heat transfer equipment.
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specifically addressing flammable refrigerants that is very similar to the Supplement SB in the 

UL 471 standard for commercial refrigerators and freezers.

6. Residential and Light Commercial Air Conditioning and Heat Pumps

This end-use includes equipment for cooling air in individual rooms, in single-family 

homes, and sometimes in small commercial buildings. This end-use differs from commercial 

comfort air conditioning, which uses chillers that cool water that is then used to cool air 

throughout a large commercial building, such as an office building or hotel. Examples of 

equipment for residential and light commercial air conditioning and heat pumps include: 

 Central air conditioners, also called unitary air conditioning or unitary split systems. These 

systems include an outdoor unit with a condenser and a compressor, refrigerant lines, an 

indoor unit with an evaporator, and ducts to carry cooled air throughout a building. Central 

heat pumps are similar but offer the choice to either heat or cool the indoor space. These 

systems are not addressed in this rule.

 Multi-split air conditioners. These systems include one or more outdoor unit(s) with a 

condenser and a compressor and multiple indoor units, each of which is connected to the 

outdoor unit by refrigerant lines. These systems are not addressed in this rule.

 Mini-split air conditioners. These systems include an outdoor unit with a condenser and a 

compressor and a single indoor unit that is connected to the outdoor unit by refrigerant lines. 

Cooled air exits directly from the indoor unit rather than being carried through ducts. These 

systems are not addressed in this rule.

 Window air conditioners. These are self-contained units that fit in a window with the 

condenser extending outside the window. These types of units would be regulated under this 

rule if it becomes final.

 Packaged terminal air conditioners and packaged terminal heat pumps. These are self-
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contained units that consist of a separate, un-encased combination of heating and cooling 

assemblies mounted through a wall. These types of units would be regulated under this rule if 

it becomes final.

 Portable room air conditioners. These are self-contained units used inside rooms that are 

designed to be moved easily from room to room, usually having wheels. They may contain 

an exhaust hose that can be placed through a window or door to eject heat to the outside.

These types of units would be regulated under this rule if it becomes final.

Of these types of equipment, window air conditioners, packaged terminal air 

conditioners, packaged terminal heat pumps, and portable room air conditioners are selfcontained equipment with the condenser, compressor, evaporator, and tubing all within casing in 

a single unit. These units all fall under the scope of the UL 484 standard for Room Air 

Conditioners. In contrast, unitary split systems, multi-split systems and mini-split systems have 

an outdoor condenser that is separated from an indoor unit. Compared to split systems, selfcontained equipment typically has smaller charge sizes, has fewer locations that are prone to 

leak, and is less likely to require servicing by a technician, thereby causing refrigerant releases. 

A lower risk of refrigerant releases and a potential for smaller releases and lower concentration 

releases would result in lower risk that flammable refrigerant could be ignited. Thus, selfcontained air conditioners and heat pumps using a flammable refrigerant have lower risk for fire 

than split systems using a flammable refrigerant.

IV. What criteria did EPA consider in determining whether to propose to list the 

substitutes as acceptable and in determining the proposed use conditions and how does 

EPA consider those criteria?

Section 612(c) of the Clean Air Act directs EPA to publish a list of acceptable

replacement substances (“substitutes”) for class I and class II substances for specific uses. EPA 
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compares the risks to human health and the environment of a substitute to the risks associated 

with other substitutes that are currently or potentially available. EPA also considers whether the 

substitute for class I and class II ODS “reduces the overall risk to human health and the

environment” compared to the ODS historically used in the end-use. The criteria we review are 

listed at 40 CFR 82.180(a)(7). These criteria are: (i) atmospheric effects and related health and 

environmental impacts; (ii) general population risks from ambient exposure to compounds with 

direct toxicity and to increased ground-level ozone; (iii) ecosystem risks; (iv) occupational risks; 

(v) consumer risks; (vi) flammability; and (vii) cost and availability of the substitute.

EPA evaluated each of the criteria for each substitute in each end-use for which we are 

proposing action and then for each substitute we considered overall risk to human health and the 

environment in comparison to other available or potentially available alternatives in the same 

end-uses. Based on our evaluations, we may reach different conclusions on the same substitute in 

different end-uses, because of different risk profiles (e.g., different exposure levels and usage 

patterns) and different sets of available or potentially available substitutes for each end-use. 

As noted previously on May 17, 2013, at 78 FR 29035, environmental and human health 

exposures can vary significantly depending on the particular application of a substitute – and 

over time, information available regarding a substitute can change. SNAP’s comparative risk 

framework does not imply fundamental tradeoffs with respect to different types of risk, either to 

the environment or to human health. EPA recognizes that during the nearly two-decade history

of the SNAP program, new information about alternatives already found acceptable and new 

alternatives have emerged. To the extent possible, EPA considers current information that

improves our understanding of the risk factors for the environment and human health in the 

context of the available or potentially available alternatives for a given use. 

A. Effects on the environment
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The SNAP program considers a number of environmental criteria when evaluating 

substitutes: ozone depletion potential (ODP); climate effects, primarily based on global warming 

potential (GWP); local air quality impacts, particularly potential impacts on smog formation 

from emissions of volatile organic compounds (VOC); and ecosystem effects, particularly from 

negative impacts on aquatic life. These and other environmental and health risks are discussed 

below.

The ODP is the ratio of the impact on stratospheric ozone of a chemical compared to the 

impact of an identical mass of CFC–11. Thus, the ODP of CFC–11 is defined to be one (1.0). 

Other CFCs and HCFCs have ODPs that range from 0.01 to one (1.0). 

All refrigerant substitutes in this proposal have an ODP of zero, lower than the ODP of 

the ozone depleting substances that they replace: CFC–12 (ODP = 1.0); HCFC–22 (ODP = 

0.055); R-13B1 (ODP = 10) and R–502 (ODP = 0.334). The most commonly used substitutes in 

the end-uses addressed in this proposal also have an ODP of zero (e.g., R–404A, R– 134a, R–

410A, and R–407C).11 Some less common alternatives for these end-uses, such as R-401A, R414A and other blends containing HCFC-22 or HCFC-142b,

12 have ODPs ranging from 0.01 to 

0.047. Thus, the refrigerant substitutes in this proposal have ODPs lower than or identical to the 

ODPs of other available substitutes and of the substances they replace.

The GWP is a means of quantifying the potential integrated climate forcing of various 

greenhouse gases relative to carbon dioxide. All of the hydrocarbon refrigerants in this proposal 

have a relatively low 100-year integrated GWP of less than ten. HFC-32 has a GWP of 675. For 

comparison, some other commonly used, acceptable refrigerants in these end-uses are R–134a, 

R–404A, R–407C, and R–410A with GWPs of about 1,430, 3,920, 1,770, and 2,090, 

 

11 We assume that substitutes containing no chlorine, bromine, or iodine have an ODP of zero.

12 Under EPA’s phaseout regulations, virgin HCFC-22, HCFC-142b, and blends containing HCFC-22 or HCFC142b may only be used to service existing appliances. Consequently, virgin HCFC-22, HCFC-142b and blends 

containing HCFC-22 or HCFC-142b may not be used to manufacture new pre-charged appliances or appliance 

components or to charge new appliances assembled onsite.
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respectively. In very low temperature refrigeration, a common refrigerant is R-508B, with a 

GWP of 13,400. The GWPs of the ozone-depleting substances that they replace are: CFC–12 

(GWP = 10,900); HCFC–22 (GWP = 1,810); R-13B1/halon 1301 (GWP = 7,140) and R–502 

(GWP = 4,660) (IPCC, 2007). The GWPs of the substitutes reviewed in this proposal are 

significantly lower than those of other refrigerants currently being used in the residential and 

light commercial air conditioning and heat pump end-use. As stated above, EPA considers 

overall risk to human health and the environment compared to ODS as well as alternatives that 

are available and potentially available in a given end-use. Therefore, the GWP of 675 for HFC32 may not be considered low in other end-uses that have a larger variety of options available 

with lower GWPs. Among the acceptable substitutes listed in this end-use, only ammonia 

absorption and the non-vapor compression technologies evaporative cooling and desiccant 

cooling would have lower GWPs. Given technical limits on the effective use of the non-vapor 

compression technologies in different climates and the higher toxicity of ammonia than of the 

alternatives proposed here, the proposed substitutes still reduce risk overall compared to the 

available and potentially available substitutes in this end-use.

The GHG impacts of these refrigerants also depend upon the energy use of appliances, 

since the “indirect” GHG emissions associated with electricity consumption typically exceed 

those from refrigerants over the full lifecycle of refrigerant-containing products. (ORNL, 1997). 

If appliances using the refrigerants being considered in this proposal are less energy efficient 

than the appliances they replace, then it is possible that these appliances would result in higher 

lifecycle GHG emissions than appliances using a higher GWP refrigerant or refrigerant 

substitute. Conversely, higher energy efficiency of these appliances would lead to even lower 

lifecycle GHG emissions. While we have not undertaken a comprehensive assessment of all 

sources of GHG emissions associated with substituting ODS and other commonly used
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refrigerants with the proposed refrigerants, we note that for most of the types of equipment 

covered here, energy efficiency standards exist.

13 Thus, total energy use with alternative 

refrigerants can be expected to be no higher than that required by the standards for those classes 

of equipment.14 Further, testing data, peer-reviewed journal articles and other information 

provided by the submitters for these substitute refrigerants indicated that equipment using these 

refrigerants is likely to have a higher coefficient of performance and use less energy than 

equipment currently being manufactured that uses common ODS and HFC refrigerants that are 

listed as acceptable under SNAP. This implies that equipment that uses the refrigerants proposed 

to be listed will have the same or lower climate impacts than other available substitutes (Daikin, 

2011; A.S. Trust & Holdings, 2012; A.S. Vestfrost, 2012; CHEAA, 2013).

In addition to global impacts on the atmosphere, EPA evaluated potential impacts of the 

proposed substitutes on local air quality. Ethane and HFC-32 are exempt from the definition of 

VOC under CAA regulations (see 40 CFR 51.100(s)) addressing the development of State 

Implementation Plans (SIPs) to attain and maintain the national ambient air quality standards. 

The other proposed refrigerants, isobutane, propane, and components of R-441A, including 

isobutane, n-butane and propane, are VOC. Potential emissions of VOC from all substitutes for 

all end-uses in the refrigeration and air conditioning sector are addressed by the venting 

prohibition under Section 608 of the CAA. Under that prohibition, refrigerant substitutes (and 

thus the VOC they contain) may only be emitted where EPA issues a final determination 

 

13 For example, Department of Energy (DOE) standards apply to portable air conditioners, room air conditioners, 

PTACs and PTHPs, household refrigerators and freezers, refrigerated beverage vending machines, and commercial 

refrigeration equipment. See 

https://www1.eere.energy.gov/buildings/appliance_standards/standards_test_procedures.html.

14 Refrigeration or air conditioning equipment in the applicable covered equipment class would still be subject to 

DOE’s standards, regardless of the refrigerant that the equipment uses. If a manufacturer believes that its design is 

subjected to undue hardship by DOE’s regulations, the manufacturer may petition DOE’s Office of Hearing and 

Appeals (OHA) for exception relief or exemption from the standard pursuant to OHA’s authority under section 504 

of the DOE Organization Act (42 U.S.C. 7194), as implemented at subpart B of 10 CFR part 1003. OHA has the 

authority to grant such relief on a case-by-case basis if it determines that a manufacturer has demonstrated that 

meeting the standard would cause hardship, inequity, or unfair distribution of burdens.
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exempting a refrigerant substitute from the venting prohibition on the basis that venting, 

releasing or disposing of such substance does not pose a threat to the environment, as proposed 

elsewhere in this action (see Section VI, “How is EPA proposing to address venting, release, or 

disposal of the refrigerant substitutes proposed to be listed under section 608 of the Clean Air 

Act?” below). EPA estimates that potential emissions of hydrocarbons when used as refrigerant

substitutes in all end-uses in the refrigeration and air conditioning sector have little impact on 

local air quality, with the possible exception of unsaturated hydrocarbons such as propylene 

(ICF, 2013a). However, for those refrigerants that are VOC as defined in 40 CFR 50.100(s), a 

State could adopt additional control strategies if necessary for an ozone nonattainment area to 

attain the National Ambient Air Quality Standard (NAAQS) for ozone. 

EPA analyzed a number of scenarios to consider the potential impacts on local air quality 

if hydrocarbon refrigerants were used widely. We used EPA’s Vintaging Model to estimate the 

hydrocarbon emissions from these scenarios and EPA’s Community Multiscale Air Quality

(CMAQ) model to assess their potential incremental contributions to ground-level ozone 

concentrations (ICF, 2013a). That analysis assumed that the most reactive hydrocarbon proposed 

to be acceptable (isobutane) was used in all refrigeration and air conditioning uses, and that all 

refrigerant used was emitted to the atmosphere even though isobutane is not being proposed as 

acceptable for use in all refrigeration and air conditioning uses. In that extreme scenario, the 

model predicted that the maximum increase in the 8-hour average ground-level ozone 

concentration would be 0.72 ppb in Los Angeles. Further, in the analysis, the additional groundlevel ozone did not result in exceeding the NAAQS where an area was in compliance without the 

additional refrigerant emissions. Given the potential sources of uncertainty in the modeling, the 

conservativeness of the assumptions, and the finding that the incremental VOC emissions from

this refrigerant emissions would not cause any area that otherwise would meet the NAAQS to 
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exceed it, we believe that the use of isobutane consistent with the use conditions will not result in 

significantly greater risk to the environment than other substitutes that are currently or 

potentially available. Further, propane, ethane, and n-butane, the remaining component of R441A, are less reactive than isobutane and we reach a similar conclusion for those refrigerants. 

EPA also analyzed the potential impacts of the uses of hydrocarbon refrigerants proposed 

to be acceptable under this rule. In this less conservative analysis, EPA looked at a set of enduses that would be more likely to use hydrocarbon refrigerants between now and 2030. The 

analysis assumed use of hydrocarbon refrigerants in those uses for which UL currently has 

standards in place, for which the SNAP program has already listed the uses as acceptable subject 

to use conditions, or for which the SNAP program is reviewing a submission, including those in 

this rule.

15 In addition, the air quality analysis assumed several different hydrocarbons16 would 

be used based upon those under review by the SNAP program in the end-uses for which they

were submitted. For example, we assumed use of propane, R-441A, and another hydrocarbon 

refrigerant under review in room air conditioners and isobutane, propane, and R-441A in 

vending machines, stand-alone retail food refrigeration equipment, and household refrigerators 

and freezers, but no use of hydrocarbons in chillers used for air conditioning of large buildings. 

(For further information on the specific assumptions, see ICF, 2013a, in the docket for this 

rulemaking.) Based on this still conservative but more probable assessment of refrigerant use, we 

found that even if all the refrigerant in appliances in end-uses addressed in this proposed rule 

were to be emitted, there would be a worst-case impact of 0.15 ppb ozone in the Los Angeles 

 

15 The analysis included stand-alone commercial refrigerators, freezers, and coolers; vending machines; 

refrigerated transport; water coolers; commercial ice machines; household refrigerators and freezers; and 

room air conditioners (window AC, packaged terminal AC and packaged terminal heat pumps). The 

analysis did not expressly break out very low temperature refrigeration or non-mechanical heat transfer 

from commercial refrigerators and freezers.

16 Refrigerants in this scenario included propane, isobutane, and R-441A in the end-uses where they are 

proposed to be acceptable subject to use conditions, among others. Ethane was not expressly included, 

since the type of equipment using ethane is not broken out separately in the analysis. However, ethane is 

less reactive than the other refrigerants included in the analysis, so this omission is expected to result in a 

slight overestimation of impacts, if any.
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area, which is the area with the highest level of ozone pollution in the United States. In the other 

cities examined in the analysis, Houston and Atlanta, impacts were smaller (no more than 0.03 

and 0.01 ppb, respectively) (ICF, 2013a). These impacts did not cause any areas to exceed the 

NAAQS that otherwise would have met the NAAQS without the additional refrigerant 

emissions. Because of the relatively low air quality impacts of these refrigerants if they are 

released to the atmosphere in limited amounts, EPA believes that these refrigerants do not have a 

significantly greater impact on human health and the environment based on their effects on local 

air quality than other refrigerants listed as acceptable in the end-uses proposed in this rule.

The substitutes in this proposal are all highly volatile. They typically evaporate or 

partition to air, rather than contaminating surface waters. Effects on aquatic life of the substitutes 

are expected to be small and pose no greater risk of aquatic or ecosystem effects than those of 

other available substitutes for these uses.

Based on EPA’s analysis, the overall environmental risks, including ODP, GWP, local air 

quality effects and ecosystem impacts are lower than or comparable to those of other acceptable 

substitutes in the same end-uses. 

B. Flammability and fire safety

The flammability risks of the proposed substitutes are of potential concern because 

household and retail food refrigerators and freezers and room AC units have traditionally used 

refrigerants that are not flammable. Without appropriate use conditions, the flammability risk 

posed by these refrigerants could be higher than non-flammable refrigerants because individuals 

may not be aware that their actions could potentially cause a fire, and existing equipment has not

been designed specifically to minimize flammable risks. In this section, we discuss the risks 

posed by the refrigerants considered in this rule and explain the proposed use conditions we 

believe are necessary to mitigate risks to ensure that the overall risk to human health and the 
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environment posed by these proposed substitutes is not greater than the overall risk posed by 

other substitutes in the same end-uses. In addition, we discuss why the flammability risks have 

led us to propose that these substitutes are only acceptable for use in new equipment specifically 

designed for these flammable refrigerants. 

Due to their flammable nature, ethane, isobutane, propane, HFC-32, and R-441A could 

pose a significant safety concern for workers and consumers in the end-uses addressed in this 

proposal if they are not handled correctly. In the presence of an ignition source (e.g., static 

electricity spark resulting from closing a door, using a torch during service, or a short circuit in 

wiring that controls the motor of a compressor), an explosion or a fire could occur when the

concentration of refrigerant exceeds its lower flammability limit (LFL). The LFLs of the 

proposed substitutes are: ethane—30,000 ppm; HFC-32—139,000 ppm; isobutane—18,000 

ppm; propane—21,000 ppm; and R-441A—20,500 ppm. Therefore, to use these substitutes 

safely, it is important to minimize the presence of potential ignition sources and to reduce the

likelihood that the levels of ethane, HFC-32, isobutane, propane, or R-441A will exceed the

LFL. Under the proposed listing decision, these substitutes would be acceptable for use only in 

new equipment (refrigerators, freezers and air conditioners) specifically designed for the 

refrigerant. We expect that the original equipment manufacturers, who would be storing large

quantities of the refrigerant, are familiar with and use proper safety precautions to minimize the

risk of explosion, due to OSHA and building code requirements. We are proposing to include in 

the “Further Information” section of the SNAP listings recommendations that these facilities be 

equipped with proper ventilation systems and be properly designed to reduce possible ignition 

sources. 

To determine whether flammability would be a concern for manufacturing and service 

personnel or for consumers, EPA analyzed a plausible worst-case scenario to model a 
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catastrophic release of the proposed refrigerants. The worst-case scenario analysis for each 

refrigerant revealed that even if the unit’s full charge is emitted within one minute, none of these 

refrigerants reached their respective LFLs of 1.8% for isobutane, 2.1% for propane, 2.05% for R441A, or 3.0% for ethane, provided that the charge sizes were no greater than those specified in 

the relevant standard from Underwriters Laboratories (ICF, 2013b,c,d,e,f,g,h,i,j,k). Thus, there 

would not be an excessive risk of fire or explosion, even under those worst-case assumptions, so 

long as the charge meets the use conditions in this proposed rule. Detailed analysis of the

modeling results are discussed below in the next section regarding “Toxicity.” EPA also

reviewed the submitters’ detailed assessments of the probability of events that might create a fire

and engineering risk and approaches to avoid sparking from the refrigeration equipment. Further 

information on these analyses and EPA’s risk assessments are available in public docket EPAHQ-OAR-2013-0748 at www.regulations.gov. Although the analysis showed no potential for the 

released refrigerant from one piece of equipment to reach the LFL, manufacturing and service 

personnel or consumers are not familiar with refrigeration or air conditioning equipment 

containing a flammable refrigerant. Therefore, use conditions are necessary to ensure people 

handling such equipment are aware that equipment contains a flammable refrigerant and to 

ensure safe handling. This allows the flammable refrigerants to be used without increasing 

overall risk to human health and the environment.

C. Toxicity

In evaluating potential toxicity impacts of ethane, HFC-32, isobutane, propane, and R441A on human health, EPA considered both occupational and consumer risks. EPA investigated

the risk of asphyxiation and of exposure to toxic levels of refrigerant for a worst-case scenario 

and a typical use scenario for each refrigerant. In the worst-case scenario of a catastrophic leak, 

we modeled release of the unit’s full charge within one minute into a confined space to estimate 
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concentrations that might result. We considered a conservatively small space appropriate to each

end-use, such as a small convenience store of 244 m3for retail food refrigeration, a small galley

kitchen of 18 m3for a household refrigerator/freezer, or a small bedroom of 41 m3for a room air 

conditioner. 

To evaluate toxicity of all five refrigerants, EPA estimated the maximum time-weighted 

average (TWA) exposure both for a short-term exposure scenario, with a 15-minute and 30-

minute TWA exposure, and for an 8-hour time weighted average that would be more typical of 

occupation exposure for a technician servicing the equipment. We compared these short-term 

and long-term exposure values to relevant industry and government workplace exposure limits 

for ethane, HFC-32, isobutane, propane, and components of R-441A, (including potential 

impurities in the substitutes). The modeling results indicate that both the short-term (15-minute 

and 30-minute) and long-term (8-hour) worker exposure concentrations would be below the 

relevant workplace exposure limits, such as the Occupational Safety and Health Administration 

(OSHA) permissible exposure limit (PEL), the National Institute for Occupational Safety and

Health’s (NIOSH) recommended exposure limit (REL), the American Conference of 

Governmental Industrial Hygienists’ (ACGIH) threshold limit value (TLV), or in the case of 

HFC-32, the manufacturer’s recommended workplace exposure limit. In some cases where there 

was not an established short-term exposure limit (STEL), we considered information on shortterm exposure such as the no observed adverse effect level (NOAEL) from available toxicity

studies or the National Research Council’s Acute Emergency Guideline Limits (AEGL)17. The 

 

17 The AEGL limit is an emergency guideline for exposures to the general population (including

susceptible populations) and is not time-weighted. It also considers the chemical’s flammability in

addition to its toxicity. EPA develops a set of AEGL values for a chemical for five exposure periods (10

and 30 minutes, 1 hour, 4 hours and 8 hours). For each exposure period, three different AEGL values are 

developed to address different levels of toxicological impacts. Of relevance for the modeled scenario is

the AEGL–1 (10,000 ppm), which is defined as: “the airborne concentration, expressed as parts per

million or milligrams per cubic meter (ppm or mg/m3) of a substance above which it is predicted that 

the general population, including susceptible individuals, could experience notable discomfort, 

irritation, or certain asymptomatic nonsensory effects. However, the effects are not disabling and are
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respective workplace exposure limits we considered for the various compounds, including 

components of the refrigerant blend R-441A, are as follows:

 n-Butane, a component in R-441A: 800 ppm REL on 10-hr TWA; 6,900 ppm AEGL1 over 30 minutes

 Ethane: 1000 ppm TLV on 8-hour TWA

 HFC-32: 1000 ppm manufacturer’s exposure guideline on 8-hour TWA; 3000 ppm 

over 15 minutes

 Isobutane: 800 ppm REL on 10-hr TWA; 18,000 ppm NOAEL over 30 minutes

 Propane: 1000 ppm PEL on 8-hr TWA; 6,900 ppm AEGL-1 over 30 minutes

For equipment with which consumers might come into contact, such as retail food 

refrigerators and freezers, vending machines, household refrigerators and freezers, and room air 

conditioners, EPA performed a consumer exposure analysis. In this analysis, we examined 

potential catastrophic release of the entire charge of the substitute in one-minute under a worstcase scenario. We did not examine exposure to consumers in very low temperature refrigeration, 

as equipment for this end-use would typically be used in the workplace, such as in laboratories, 

and not in a home or public space. The analysis was undertaken to determine the 15-minute or 

30-minute TWA exposure levels for the substitute, which were then compared to the toxicity

limits to assess the risk to consumers.

EPA considered toxicity limits for consumer exposure that reflect a short-term exposure 

such as might occur at home or in a store or other public setting where a member of the general 

public could be exposed and then could escape. Specific toxicity limits that we used in our 

analysis of consumer exposure include:

 

transient and reversible upon cessation of exposure.” While permanent toxicological effects are not

expected up to the AEGL–2 value, this limit is not relevant for this analysis because at that level, 

flammability would be a greater concern.
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 n-Butane: 6,900 ppm AEGL-1 over 30 minutes

 HFC-32: cardiotoxic NOAEL of 350,000 ppm over 5 minutes

 Isobutane: 18,000 ppm NOAEL over 30 minutes

 Propane: 6,900 ppm AEGL-1 over 30 minutes

The analysis of consumer exposure assumed that 100 percent of the unit’s charge would 

be released over one minute, at which time the concentration of refrigerant would peak in an 

enclosed space, and then steadily decline. Refrigerant concentrations were modeled under two air 

change scenarios, believed to represent the baseline of potential flow rates for a home or other 

public space, assuming flow rates of 2.5 and 4.5 air changes per hour (ACH) (Sheldon 1989). 

The highest concentrations of the refrigerant occur in the lower stratum of the room when 

assuming the lower ventilation level of 2.5 ACH. Calculating the TWA exposure using 2.5 ACH 

results in a higher concentration than calculating the TWA exposure using 4.5 ACH. Even under 

the very conservative assumptions used in the consumer exposure modeling, the estimated 15-

minute or 30-minute consumer exposures to the proposed refrigerants are much lower than the 

relevant toxicity limits and thus should not pose a toxicity risk any greater than that of other 

acceptable refrigerants in the proposed end-uses.

For further information, including EPA’s risk screens and risk assessments as well as

fault tree analyses from the submitters of the substitutes, see docket number EPA–HQ–OAR–

2013-0748 at www.regulations.gov.

V. Why is EPA proposing these specific use conditions?

EPA is proposing to list ethane, isobutane, propane, HFC-32, and R-441A as acceptable 

subject to use conditions in the specified end-uses. EPA is proposing these uses in new 

equipment designed and manufactured specifically to use these alternatives. The use conditions 

include conditions consistent with industry standards, limits on charge size, and requirements for 
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warnings and markings on equipment to inform consumers and technicians of potential 

flammability hazards. The proposed listings with the specific use conditions are intended to

allow for the use of these flammable refrigerants in a manner that will ensure they do not pose a 

greater risk to human health or the environment than other substitutes that are currently or 

potentially available. We seek comment on the proposed listing as well as the specific use 

conditions discussed below.

A. New equipment only; not intended for use as a retrofit alternative

EPA is proposing that the flammable refrigerants considered in this proposal be limited to 

use only in new equipment that has been designed and manufactured specifically for use with the 

listed alternative refrigerant. We are proposing that these substitutes may be used only in new 

equipment18 that is designed to address concerns unique to flammable refrigerants. The 

flammable refrigerants were not submitted under the SNAP program to be used in retrofitted 

equipment, and no information was provided on how to address hazards of flammable 

refrigerants when used in equipment that was designed for non-flammable refrigerants. 

Introduction into interstate commerce of these refrigerants for use in existing equipment without 

giving timely and adequate notice to EPA would be in violation of section 612(e) of the CAA 

and the SNAP regulations at 40 CFR Part 82, Subpart G. In addition, if the rule is finalized as 

proposed, use of these refrigerants in existing equipment would be in violation of section 612(c)

of the CAA and the corresponding SNAP regulations at 40 CFR Part 82, Subpart G.

B. Standards

EPA is proposing that the flammable refrigerants be used only in equipment that meets 

all requirements in the relevant supplements for flammable refrigerants in certain applicable UL

 

18 This is intended to mean a completely new refrigeration circuit containing a new evaporator, condenser 

and refrigerant tubing. We are aware that for some types of equipment, e.g., vending machines, it is 

possible to detach easily and replace the refrigeration circuit from the outer casing of the equipment. In 

such a situation, replacing the old refrigeration circuit with a new one within the old casing would be 

considered “new” equipment and not a retrofit of the old, existing equipment.
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Standards for refrigeration and air conditioning equipment. Specifically, the standards cited 

include UL 471 10thedition for commercial refrigerators and freezers (including stand-alone 

freezers for very low temperature refrigeration), UL 250 10th edition (for household refrigerators 

and freezers), UL 541 7

th edition for refrigerated vending machines, and UL 484 8th edition for 

room air conditioners.

UL has tested equipment for flammability risk in both household and retail food

refrigeration. Further, UL has developed acceptable safety standards including requirements for 

construction, for markings, and for performance tests concerning refrigerant leakage, ignition of 

switching components, surface temperature of parts, and component strength after being 

scratched. These standards were developed in an open and consensus-based approach, with the 

assistance of experts in the air-conditioning and refrigeration industry as well as experts involved 

in assessing the safety of products. While similar standards exist from other bodies such as the 

International Electrotechnical Commission (IEC), we are proposing to rely on UL standards as 

those that are most applicable and recognized by the U.S. market. This proposed approach is the 

same as that in our previous rule on flammable refrigerants (December 20, 2011 at 76 FR 

78832).

C. Charge size

EPA is proposing use conditions that limit the amount of refrigerant allowed in each type 

of appliance. As before, we believe it is necessary to set limits on charge size in order for these 

refrigerants not to pose a risk to human health or the environment that is greater than the risk 

posed by other available substitutes. These limits will limit the risk to workers and consumers 

since under worst-case scenario analyses, a leak of the proposed charge sizes did not result in 

concentrations of the refrigerant that met or exceeded the LFL, as explained above in Section 

IV.B, “Flammability and fire safety.”
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EPA is proposing limitations on refrigerant charge size for household and stand-alone 

commercial refrigerators and freezers, vending machines, and room air conditioning units that 

reflect the UL 250, UL 471, UL 541 and UL 484 standards. As discussed above in paragraph B 

of this section, we believe UL standards are most applicable to the U.S. market and offer 

requirements developed by a consensus of experts. EPA is proposing a charge size not to exceed

57 grams (2.01 ounces) for household refrigerators and freezers, not to exceed 150 grams (5.29

ounces) for retail food refrigeration in stand-alone units, and not to exceed 150 grams (5.29

ounces) for vending machines. We are proposing a varying charge size limit for room air 

conditioning units as discussed below. To place these quantities in a familiar context, EPA 

estimates the charge size of a disposable lighter is equal to 30 grams (1.06 ounces). 

The UL 250 standard for household refrigerators and freezers limits the amount of

refrigerant that may leak to 50 grams (1.76 ounces). EPA is proposing a charge size of 57 grams

(2.01 ounces) to allow for up to 7 grams (0.25 ounces) of refrigerant that might be solubilized in

the oil (and assumed not to leak or immediately vaporize with the refrigerant in the case of a

leak). EPA bases this estimate on information received from a manufacturer of hydrocarbonbased refrigerator-freezers (see EPA-HQ-OAR-2013-0748 on www.regulations.gov).

UL standards 541 (retail food refrigeration) and 471 (vending machines) limit the amount 

of refrigerant leaked to 150 grams (5.29 ounces). Furthermore, the charge size limit for A3 

refrigerants (for retail food refrigeration) is in line with the IEC 60335–2–89 standard for 

commercial appliances, which has a charge size limit of 150 grams (5.29 ounces).

As noted above, EPA is proposing a varying charge size for room air conditioning units. 

We are proposing that the maximum charge must be no greater than the amount calculated for a 

given sized space according to Appendix F to Supplement SA of UL Standard 484. This section 

of the UL standard uses a formula for charge of a fixed room air conditioner based upon the size 
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of the space where the refrigerant may escape and the lower flammability limit of the refrigerant. 

The formula is as follows:

Where,

Mmax is the maximum charge size allowed for the space, in kg,

LFL is the lower flammability limit of the refrigerant in kg/m3,

h0 is the installation height of the indoor unit in m (0.6 m for an AC unit on the floor, 1.0 

m for an AC unit in a window, 1.8 m for a wall-mounted AC unit, and 2.2 m for a 

ceiling-mounted AC unit), and

A is the floor area of the room, in m2. 

The equipment manufacturer would then design AC units to be used in rooms with a minimum 

size and would label the minimum room size on the equipment. Table 2 below gives examples of 

room sizes and appropriate charge sizes for the three refrigerants proposed to be listed for use in 

room AC units, assuming a typical height of 1.0 m for a window-mounted unit.

In addition to the formula mentioned above, UL 484 has a requirement that the maximum 

charge for a room air conditioner may not exceed the amount calculated using the following 

formula:

Where,

m2 is the maximum charge size allowed, in kg, 

26 m3is a constant, and

LFL is the lower flammability limit of the refrigerant in kg/m3.

That formula sets maximum limits on refrigerant in a room air conditioner, as shown in 

Table 2. With the A3 refrigerants, the maximum value is 1 kg.
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Table 2. Maximum refrigerant charge sizes 

If you are 

using this 

refrigerant

...

Then its lower 

flammability limit 

is...

The 

maximum 

allowable 

charge in kg 

for room air 

conditioner 

is...

And the maximum charge, in 

kg, to use in a room of this 

size19 is...

In % by 

volume

In 

kg/m3

1.7 m x 

1.7 m x 

2.5 m 

(7.2 m3)

A=2.89 

m

2

6 ft x 8 

ft x 8 ft 

(384 ft3/ 

10.9 

m

3

)

A=4.46

m

2

12 ft x 

10 ft x 

10 ft 

(1200 ft3/ 

34.0 m3)

A=11.15 

m

2

HFC-32 14.4 0.306 7.979 0.971 1.192 1.900

Propane (R290)2.1 0.038 0.986 0.071 0.087 0.139

R-441A 2.05 0.041 1.000 0.078 0.095 0.152

Although using a formula to determine the maximum charge size and minimum room 

size is appropriate from an engineering perspective, it does not ensure that a consumer will select 

an appropriate AC unit for the size of their room. It is likely that some consumers may be 

unaware of the exact size of the room to be cooled and thus may select an inappropriately sized 

AC unit that increases the flammability risk. A consumer may believe that a larger, more 

powerful AC unit will provide better, faster cooling and therefore may select an inappropriately

sized AC unit that increases the flammability risk. To address these concerns, EPA proposes to

supplement the charge size guidelines in Appendix F of UL 484 with a use condition that 

restricts the maximum refrigerant charge of equipment based upon the cooling capacity needed,

in British thermal units (BTU) per hour. Equipment manufacturers would be responsible for 

designing equipment below a maximum charge size consistent with the intended cooling 

capacity. This would allow the manufacturer, who has greater understanding of the issue than a 

consumer, to address the issue in a manner under the manufacturer’s control. Placing the burden 

on the manufacturer also provides a better means for EPA to ensure compliance and thus to 

ensure that the risk to human health will not be greater than that posed by other available 

 

19 Although the height of the room does not affect the calculation, typical heights are shown here for reference.
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substitutes. 

We believe that these requirements, in combination with the other use conditions and 

commonly found informational materials, provide sufficient safeguards against instances of 

consumers selecting inappropriately-sized equipment. For instance, packaging, technical 

literature and sales display material will often guide a consumer in choosing the correct capacity 

for a given room size.

EPA has based its proposed charge limits upon appropriate capacity needs for an area to 

be cooled and the requirements for refrigerant charge relative to room size in Appendix F of UL

484, discussed above. A document in the docket describes this relationship in tables in a 

spreadsheet (EPA, 2013). The proposed charge limits for each refrigerant by equipment type and 

mounting location are as follows:
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Table 3. Window AC Units*;

Maximum Charge Size by Unit Capacity and Refrigerant Used in Kg

Refrigerant Charge Size in Kg (by associated capacity in BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 1.73 2.12 2.74 3.00 3.24 3.47 3.68 4.07 4.59 5.48 6.01 6.49 6.72 7.76

R-290 0.13 0.16 0.20 0.22 0.24 0.26 0.27 0.30 0.34 0.40 0.44 0.48 0.50 0.57

R-441A 0.14 0.17 0.22 0.24 0.26 0.28 0.30 0.33 0.37 0.44 0.49 0.53 0.54 0.63

*Assumes the evaporator is at least 1 m, but not more than 1.8 m, above the floor. Cooling capacities between those in the table are to be linearly 

interpolated between the next smaller and larger capacities listed in the table.

Table 4. Packaged Terminal AC Units and Heat Pumps and Portable AC Units:* 

Maximum Charge Size by Unit Capacity and Refrigerant Used in Kg

Refrigerant

Charge Size in Kg (by associated capacity in BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 1.04 1.27 1.65 1.80 1.95 2.08 2.21 2.44 2.75 3.29 3.60 3.89 4.03 4.65

R-290 0.08 0.09 0.12 0.13 0.14 0.15 0.16 0.18 0.20 0.24 0.27 0.29 0.30 0.34

R-441A 0.08 0.10 0.13 0.15 0.16 0.17 0.18 0.20 0.22 0.27 0.29 0.32 0.33 0.38

*Assumes the evaporator is at least 0.6 m, but not more than 1.0 m, above the floor. Cooling capacities between those in the table are to be linearly 

interpolated between the next smaller and larger capacities listed in the table.
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Table 5. Wall-Mounted AC Units* with Compressor 1.8 m Above Floor Level: 

Maximum Charge Size by Unit Capacity and Refrigerant Used in Kg

Refrigerant

Charge Size in Kg (by associated capacity in BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 3.12 3.82 4.94 5.41 5.84 6.24 6.62 7.32 8.26 9.87 10.81 11.68 12.09 13.96

R-290 0.23 0.28 0.36 0.40 0.43 0.46 0.49 0.54 0.61 0.73 0.80 0.86 0.89 1.00

R-441A 0.25 0.31 0.40 0.44 0.47 0.51 0.54 0.59 0.67 0.80 0.88 0.95 0.98 1.00

*Assumes the evaporator is at least 1.8 m, but not more than 2.2 m, above the floor. Cooling capacities between those in the table are to be linearly interpolated between 

the next smaller and larger capacities listed in the table.

Table 6. Ceiling-Mounted AC Units*: 

Maximum Charge Size by Unit Capacity and Refrigerant Used in Kg

Refrigerant

Charge Size in Kg (by associated capacity in BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 3.82 4.67 6.03 6.61 7.14 7.63 8.09 8.95 10.09 12.07 13.22 14.28 14.78 17.06

R-290 0.28 0.34 0.44 0.49 0.53 0.56 0.60 0.66 0.74 0.89 0.97 1.00 1.00 1.00

R-441A 0.31 0.38 0.49 0.54 0.58 0.62 0.66 0.73 0.82 0.98 1.00 1.00 1.00 1.00

*Assumes the evaporator is at least 2.2 m above the floor. Cooling capacities between those in the table are to be linearly interpolated between the next smaller and larger 

capacities listed in the table.
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In cases where the rated capacity exceeds the maximum shown on the table, the maximum charge 

size in the table for that refrigerant applies. In cases where the normal rated capacity lies between two 

values listed next to each other in the table, the maximum charge size would be determined based on a 

linear interpolation between the two respective charge sizes. We assume that room air conditioners will be 

at least 5,000 BTU/hr in capacity; this corresponds to cooling a floor area of roughly 100 square feet or 

9.3 m2and it is the lowest value observed at a popular retailer’s website (www.homedepot.com). We 

request comment on whether there should be lower, higher, or additional intermediate capacity values 

added to these tables.

EPA is requesting comment on the approach of adding a requirement for manufacturers to design 

with a maximum charge size consistent with the design cooling capacity. We also request comment on 

other potential methods for supplementing the formulas for calculating charge size in the UL 484 standard 

in order to reduce potential risks of a consumer using a room air conditioner with an inappropriately high 

charge that could result in a higher risk of fire.

D. Color-coded hoses and piping

EPA proposes that equipment must have distinguishing color-coded hoses and piping to indicate 

use of a flammable refrigerant. This will help technicians immediately identify the use of a flammable

refrigerant, thereby potentially reducing the risk of using sparking equipment or otherwise having an 

ignition source nearby. The air conditioning and refrigeration industry currently uses distinguishing colors

as means for identifying different refrigerants. Likewise, distinguishing coloring has been used elsewhere 

to indicate an unusual and potentially dangerous situation, for example in the use of orange-insulated 

wires in hybrid electric vehicles. Currently, no industry standard exists for color-coded hoses or pipes for 

ethane, HFC-32, isobutane, propane, or R-441A. EPA is proposing that all such refrigerator tubing be 

colored red Pantone Matching System (PMS) #185 to match the red band displayed on the container of 

flammable refrigerants under the Air Conditioning, Heating and Refrigeration Institute (AHRI) Guideline 

“N” 2012, “2012 Guideline for Assignment of Refrigerant Container Colors.” This proposal mirrors the 
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existing requirement for the use of hydrocarbons in residential and commercial refrigerator-freezers

(December 20, 2011, at 76 FR 78832). EPA wants to ensure that there is adequate notice that a flammable 

refrigerant is being used within a particular piece of equipment or appliance. One mechanism to 

distinguish hoses and pipes is to add a colored plastic sleeve or cap to the service tube. The colored plastic

sleeve or cap would have to be forcibly removed in order to access the service tube. This would signal to

the technician that the refrigeration circuit that she/he was about to access contained a flammable

refrigerant, even if all warning labels were somehow removed. This sleeve would be of the same red color 

(PMS #185) and could also be boldly marked with a graphic to indicate the refrigerant was flammable. 

This could be a cost-effective alternative to painting or dying the hose or pipe. EPA is taking comment on 

this mechanism of distinguishing the pipe and hose by adding a colored plastic sleeve or cap to the pipe or 

hose.

EPA is particularly concerned with ensuring adequate and proper notification for servicing and

disposal of appliances containing flammable refrigerants. EPA believes the use of color-coded hoses, as 

well as the use of warning labels discussed below, would be reasonable and would be consistent with 

other general industry practices. This proposed approach is the same as that adopted in our previous rule 

on flammable refrigerants (December 20, 2011, at 76 FR 78832). EPA is interested in receiving 

information on how this requirement has been implemented for those end-uses that are already subject to 

the earlier rule, codified in Appendix R to Subpart G of 40 CFR Part 82.

E. Labeling

As a use condition, EPA is proposing to require labeling of household and retail refrigerators and 

freezers, vending machines, non-mechanical heat transfer equipment, very low temperature refrigeration 

equipment, and room air conditioners. EPA is proposing the warning labels on the equipment contain 

letters at least 1⁄4 inch high. The label must be permanently affixed to the equipment until its end of life. 

Warning label language requirements are found in Section III.A of this proposal, “What listings is EPA

proposing in this action?” The warning label language is similar to or exactly the same as that required in 
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UL standards: for household refrigerators and freezers in UL 250 in section SA6.1, for vending machines 

in UL 541 in section SA6.1, for commercial refrigerators and freezers in UL 471 in section SB6.1, and for 

room air conditioning units in UL 484 in section SA6.1.

EPA believes that it would be difficult to see warning labels with the minimum lettering height 

requirement of 1⁄8 inch in these UL standards. Therefore, as in the requirements in our previous 

hydrocarbon refrigerants rule (December 20, 2011, at 76 FR 78832), EPA is proposing the minimum 

height for lettering must be 1⁄4 inch as opposed to 1⁄8 inch, which will make it easier for technicians, 

consumers, retail storeowners, and first responders to view the warning labels. We also understand that 

UL is considering revising its standards to be consistent with this requirement, which already applies to 

equipment using propane in commercial stand-alone refrigerators and freezers and equipment using 

isobutane or R-441A in household refrigerators, freezers, and combination refrigerator/freezers. 

F. Other options not included

EPA considered requiring separate servicing fittings for use with flammable refrigerants to avoid 

mixing flammable and non-flammable refrigerants. We previously considered this option and proposed 

this as a use condition in a separate rulemaking in the Federal Register at 75 FR 25799 on May 10, 2010. 

In the associated final rule at 76 FR 78848 on December 20, 2011, the Agency did not require separate 

servicing fittings but did include this option as a recommendation rather than a use condition. The types 

of equipment addressed in this rule are self-contained pieces of equipment with a hermetically sealed 

refrigerant circuit that is only rarely serviced. These are the same as or similar to the equipment addressed 

in the December 20, 2011, rule, and thus with regards to separate servicing fittings we are proposing to 

again list this as a recommendation rather than as a use condition. We have heard some anecdotal mention 

of concern about mixing of refrigerant during servicing of appliances, particularly for air conditioning 

equipment that is not self-contained. However, this rule is proposing to address only equipment that is 

self-contained. Moreover, we do not have information that would lead us to a different decision than in 

the December 20, 2011, final rule for hydrocarbon refrigerants in household and stand-alone commercial 
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refrigerators and freezers. 

We also considered requiring only one use condition for each refrigerant and end-use--to meet the 

appropriate standard from Underwriters Laboratories. We understand that UL may incorporate certain 

elements of this proposal, particularly the proposed charge limit and the type font height for labels, into 

the UL 250 standard for household refrigerators and freezers. If those provisions were the only changes 

incorporated in a revised version of Supplement A of the UL 250 standard, EPA could remove the use 

conditions for charge size and for labeling requirements, as they would already be incorporated by

reference through the use condition to follow the UL 250 standard. However, at this time, those changes 

have not been incorporated into UL 250. Therefore, EPA is proposing those use conditions as well as 

compliance with other aspects of UL 250.

VI. How is EPA proposing to address venting, release, or disposal of the refrigerant 

substitutes proposed to be listed under section 608 of the Clean Air Act?

A. What are the statutory requirements concerning venting, release, or disposal of 

refrigerants and refrigerant substitutes under section 608 of the Clean Air Act?

Section 608 of the Act as amended, titled National Recycling and Emission Reduction Program, 

requires EPA to establish regulations governing the use and disposal of ODS used as refrigerants, such as 

certain CFCs and HCFCs, during the service, repair, or disposal of appliances and industrial process 

refrigeration (IPR), including air-conditioning and refrigeration equipment. EPA's authority to propose the 

actions in this NPRM is based in part on section 608 of the Clean Air Act. Section 608(c)(1) provides 

that, effective July 1, 1992, it is:

unlawful for any person, in the course of maintaining, servicing, repairing, or disposing of an 

appliance or industrial process refrigeration, to knowingly vent or otherwise knowingly release or dispose 

of any class I or class II substance used as a refrigerant in such appliance (or industrial process 

refrigeration) in a manner which permits such substance to enter the environment. 

Section 608(c)(1) further exempts from this self-effectuating prohibition “[d]e minimis releases 

associated with good faith attempts to recapture and recycle or safely dispose” of such a substance. EPA 
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interprets releases to meet the criteria for exempted de minimis releases if they occur when the recycling 

and recovery requirements of regulations promulgated under sections 608 and 609 are followed. 40 CFR 

82.154(a)(2).

Effective November 15, 1995, section 608(c)(2) of the Act extends the prohibition in section 

608(c)(1) to knowingly venting or otherwise knowingly releasing or disposing of any refrigerant 

substitute for class I or class II substances by any person maintaining, servicing, repairing, or disposing of 

appliances or IPR. This prohibition applies to any substitute unless the Administrator determines that such 

venting, releasing, or disposing “does not pose a threat to the environment.” Thus, section 608(c) provides 

EPA authority to promulgate regulations to interpret, implement, and enforce this prohibition on venting, 

releasing, or disposing of class I or class II substances and their refrigerant substitutes, which we refer to 

as the “venting prohibition” in this NPRM.

B. What are EPA’s regulations concerning venting, releasing or disposing of refrigerant 

substitutes?

Regulations promulgated under Section 608 of the Act, published on May 14, 1993 (58 FR 

28660), established a recycling program for ozone-depleting refrigerants recovered during the servicing 

and maintenance of air-conditioning and refrigeration appliances. In the same 1993 rule, EPA also 

promulgated regulations implementing the section 608(c) prohibition on knowingly venting, releasing, or 

disposing of class I or class II controlled substances. These regulations were designed to substantially 

reduce the use and emissions of ozone-depleting refrigerants.

EPA issued a final rule on March 12, 2004, at 69 FR 11946 and a second rule on April 13, 2005, at 

70 FR 19273 clarifying how the venting prohibition in section 608(c) applies to substitutes for CFC and 

HCFC refrigerants (e.g., hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) in part or whole) 

during the maintenance, service, repair, or disposal of appliances. These regulations are codified at 40 

CFR Part 82, Subpart F. The regulation at 40 CFR 82.154(a) now states in part that:

(1)“Effective June 13, 2005, no person maintaining, servicing, repairing, or disposing of 
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appliances may knowingly vent or otherwise release into the environment any refrigerant 

or substitute from such appliances, with the exception of the following substitutes in the 

following end-uses:

i. Ammonia in commercial refrigeration, or in [IPR] or in absorption units;

ii. Hydrocarbons in [IPR] (processing of hydrocarbons);

iii. Chlorine in [IPR] (processing of chlorine and chlorine compounds);

iv. Carbon dioxide in any application;

v. Nitrogen in any application; or

vi. Water in any application.

(2) The knowing release of a refrigerant or non-exempt substitute subsequent to its 

recovery from an appliance shall be considered a violation of this prohibition. De minimis

releases associated with good faith attempts to recycle or recover refrigerants or nonexempt substitutes are not subject to this prohibition....”

As explained in EPA's earlier rulemaking concerning refrigerant substitutes, EPA has not 

promulgated regulations requiring certification of refrigerant recycling/recovery equipment intended for 

use with substitutes to date (70 FR 19275; April 13, 2005). However, as EPA noted, the lack of a current 

regulatory provision should not be considered as an exemption from the venting prohibition for

substitutes that are not expressly exempted in Section 82.154(a). EPA has also noted that, in accordance 

with section 608(c) of the Act, the regulatory prohibition at Section 82.154(a) reflects the statutory 

references to de minimis releases of substitutes as they pertain to good faith attempts to recover and 

recycle or safely dispose of non-exempted substitutes (70 FR 19275; April 13, 2005).

C. What revision to the venting prohibition has EPA recently proposed?

On April 12, 2013, at 78 FR 21871, EPA proposed to revise the existing venting prohibition for

refrigerant substitutes.20 Those proposed changes would exempt from that prohibition three hydrocarbon 

refrigerant substitutes listed as acceptable subject to use conditions in the specified end-uses under the 

SNAP program: isobutane (R–600a) and R–441A, which were listed as acceptable, subject to use 

conditions, as refrigerant substitutes in household refrigerators, freezers, and combination refrigerators 

 

20 EPA is describing that proposal in this NPRM simply for ease of reference and as a reminder of EPA’s most recent 

proposal on this subject; EPA is not here changing any aspect of that proposal or reopening the opportunity for 

comments on that NPRM.
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and freezers, and propane (R–290), which was listed as acceptable, subject to use conditions, as a 

refrigerant substitute in retail food refrigerators and freezers (stand-alone units only). That proposal does 

not apply to blends of hydrocarbons with other refrigerants or containing any amount of any CFC, HCFC, 

HFC, or PFC.

EPA proposed to determine that for the purposes of CAA section 608(c)(2), the venting, release or 

disposal of such hydrocarbon refrigerant substitutes in the specified end-uses does not pose a threat to the 

environment, considering both the inherent characteristics of these substances and the limited quantities 

used in the relevant applications. EPA additionally concluded that other authorities, controls and practices 

that apply to such refrigerants help to mitigate environmental risk from the release of those three 

hydrocarbon refrigerant substitutes. For example, state and local air quality agencies may include VOC 

emissions reduction strategies in state implementation plans developed to meet and maintain the NAAQS 

that would apply to hydrocarbon refrigerants.

D. What is EPA’s proposed determination regarding whether venting of hydrocarbons to be 

listed as acceptable subject to use conditions in the end-uses proposed in this NPRM pose a threat to the 

environment?

For purposes of section 608(c)(2) of the CAA, EPA considers two factors in determining whether 

or not venting, release, or disposal of a substitute refrigerant during the maintenance, servicing, repairing,

or disposing of appliances poses a threat to the environment. See 69 FR 11948 (March 12, 2004). First, 

EPA determines whether venting, release, or disposal of the substitute refrigerant poses a threat to the 

environment due to inherent characteristics of the refrigerant, such as global warming potential. Second, 

EPA determines whether and to what extent such venting, release, or disposal actually takes place during 

the maintenance, servicing, repairing, or disposing of appliances, and to what extent such venting, release, 

or disposal is controlled by other authorities, regulations, or practices. To the extent that such releases are 

adequately controlled by other authorities, EPA defers to those authorities. 

1. Potential environmental impacts
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EPA has evaluated the potential environmental impacts of releasing into the environment the 

hydrocarbon refrigerant substitutes that we are proposing to list under the SNAP program as acceptable 

subject to use conditions in the end-uses proposed--i.e., ethane in very low temperature refrigeration and 

non-mechanical heat transfer; isobutane in retail food refrigeration (stand-alone equipment only) and 

vending machines; propane in household refrigerators and freezers, vending machines and room AC units; 

and R-441A in retail food refrigeration (stand-alone equipment only), vending machines and room AC 

units. In particular, we assessed the potential impact of the release of additional hydrocarbons on local air 

quality and their ability to decompose in the atmosphere, their ODP and their GWPs, as well as potential 

impacts on ecosystems (see Section IV above, “What criteria did EPA consider in determining whether to 

list the substitutes as acceptable and in determining appropriate use conditions and how does EPA 

consider those factors?”). As explained in that section, the ODP of these hydrocarbons is zero, the GWPs 

are less than 10, and effects on aquatic life from these hydrocarbons are expected to be small. As to 

potential effects on local air quality, based on the analysis and modeling results described above, EPA 

concludes that the four saturated hydrocarbon refrigerant substitutes proposed to be listed as acceptable 

subject to use conditions in specific end-uses—ethane, isobutane, propane, and R-441A—are expected to 

have little impact on local air quality. In addition, when examining all hydrocarbon substitute refrigerants 

in those uses for which UL currently has standards in place, for which the SNAP program has already 

listed the uses as acceptable subject to use conditions, or for which the SNAP program is reviewing a 

submission, including those in this rule, we found that even if all the refrigerant in appliances in end-uses 

addressed in this proposed rule were to be emitted, there would be a worst-case impact of less than 0.2% 

of the NAAQS for ground-level ozone in the Los Angeles area. In light of its evaluation of potential 

environmental impacts, EPA concludes that the four hydrocarbon refrigerant substitutes in the end-uses at 

issue in this proposal are not expected to pose a threat to the environment on the basis of the limited 

quantities used in the relevant end-uses and applications and on the basis of the inherent characteristics of 

these substances (ICF, 2013a).
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2. Toxicity and Flammability

As discussed above in sections IV.B., “Flammability and fire safety” and IV.C., “Toxicity,” 

EPA’s SNAP program evaluated the potential for fire risk from flammability and toxicity risks from 

exposure to the substitute refrigerants in this proposal. EPA is providing some of that information in this 

section as well.

Hydrocarbons, including ethane, propane, isobutane and the hydrocarbon blend R–441A, are 

classified as A3 refrigerants by ASHRAE Standard 34–2010, indicating that they have low toxicity and 

high flammability. Hydrocarbons considered in this proposal have lower flammability limits (LFLs) 

ranging from 1.8% to 3.0% (18,000 ppm to 30,000 ppm). To address flammability risks, EPA is issuing 

recommendations for their safe use (see section VII, “What recommendations does EPA have for safe use 

of the proposed flammable substitute refrigerants?” below) and specified use conditions. The SNAP 

program’s analysis suggests that the use conditions proposed in this rule mitigate flammability risks.

Like most refrigerants, hydrocarbons can displace oxygen at high concentrations and cause 

asphyxiation. Various industry and regulatory standards exist to address asphyxiation and toxicity risks. 

The SNAP program’s analysis of asphyxiation and toxicity risks suggests that the use conditions proposed 

in this rule mitigate potential asphyxiation and toxicity risks. Furthermore, the Agency believes that the 

flammability risks and occupational exposures to hydrocarbons are adequately regulated by OSHA, 

building, and fire codes at a local and national level.

3. Authorities, Controls, and Practices

EPA believes that existing authorities, controls, and practices would help mitigate environmental 

risk from the release of these hydrocarbon refrigerants. Analyses performed for both this proposed rule 

and the SNAP rules issued in 1994 and 2011 (March 17, 1994, at 59 FR 13044 and December 20, 2011, at 

76 FR 38832, respectively) indicate that existing regulatory requirements and industry practices designed 

to limit and control these substances adequately control the emission of the hydrocarbon refrigerants

proposed to be listed in this action. As explained below, EPA concludes that the limits and controls under 
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other authorities, regulations or practices adequately control the release of and exposure to the four

hydrocarbon substitute refrigerants and mitigate risks from any possible release.

This conclusion is relevant to the second factor mentioned above in the overall determination of 

whether venting, release, or disposal of a substitute refrigerant poses a threat to the environment—that is, 

a consideration of the extent that such venting, release, or disposal is adequately controlled by other 

authorities, regulations, or practices. As such, this conclusion is another part of the determination that the 

venting, release, or disposal of these four hydrocarbon refrigerants would not pose a threat to the 

environment.

Industry service practices and OSHA standards and guidelines address hydrocarbon refrigeration 

equipment, include monitoring efforts, engineering controls, and operating procedures. OSHA 

requirements that apply during servicing include continuous monitoring of explosive gas concentrations 

and oxygen levels. In general, hydrocarbon emissions from refrigeration systems are likely to be 

significantly smaller than those emanating from the industrial process and storage systems, which are 

controlled for safety reasons. Further, the SNAP rule listing hydrocarbons as acceptable subject to use 

conditions for use in household and commercial stand-alone refrigerators and freezers (December 20, 

2011, at 76 FR 78832), we noted that the amount of refrigerant from a refrigerant loop is limited (57 g for 

household refrigerators and freezers, and 150 g for commercial stand-alone refrigerators and freezers), 

indicating that hydrocarbon emissions from such uses are likely to be relatively small. Similar charge 

limits are proposed to apply to very low temperature refrigeration equipment, non-mechanical heat 

transfer equipment, and vending machines, with larger but still limited charges for room air conditioners 

(1000 g for hydrocarbon refrigerants).

Hydrocarbons that are also VOC may be regulated as VOC under sections of the Clean Air Act 

that address nonattainment, attainment and maintenance of the National Ambient Air Quality Standards 

for ground level ozone, including those sections addressing development of State Implementation Plans 

and those addressing permitting of VOC sources.
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The release and/or disposal of many refrigerant substitutes, including hydrocarbons, are controlled 

by other authorities including those established by OSHA and NIOSH guidelines, various standards, and 

state and local building codes. To the extent that release during maintaining, repairing, servicing or 

disposing of appliances is controlled by regulations and standards of other authorities, EPA believes these 

practices and controls for the use of hydrocarbons are sufficiently protective. These practices and controls 

could help mitigate the risk to the environment that may be posed by the venting, release or disposal of 

these four hydrocarbon refrigerants during the maintaining, servicing, repairing, or disposing of 

appliances. This conclusion addresses the second factor in the analysis described above and is thus part of 

the determination that the venting, release, or disposal of these hydrocarbon refrigerant substitutes does 

not pose a threat to the environment.

4. Conclusion

EPA has reviewed the potential environmental impacts of four hydrocarbon refrigerant substitutes 

in the end-uses that we are proposing to list subject to use conditions under SNAP, as well as the 

authorities, controls and practices in place for those hydrocarbon refrigerant substitutes. Specifically, EPA 

concludes that these four hydrocarbon refrigerant substitutes in the proposed end-uses and subject to the 

proposed use conditions are not expected to pose a threat to the environment based on the inherent 

characteristics of these substances and the limited quantities used in the relevant applications. EPA 

additionally concludes that existing authorities, controls, and practices help mitigate environmental risk 

from the release of those four hydrocarbons in the proposed end-uses and subject to the proposed use 

conditions. In light of these conclusions and those described or identified above in this section, we are 

proposing to determine, in accordance with 608(c)(2), that based on current evidence and risk analyses, 

the venting, release or disposal of these four hydrocarbon refrigerant substitutes in the end-uses proposed 

does not pose a threat to the environment. Furthermore, EPA is proposing to exempt from the venting

prohibition at 40 CFR 82.154(a)(1) these additional uses for which hydrocarbons are being proposed to be 

found acceptable subject to use conditions under the SNAP program. 
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EPA seeks information or data on whether there currently is an industry standard for recovery

units for flammable refrigerants and whether there are commercially available recovery units that are 

specifically designed to be compatible with ethane, isobutane, propane, and R-441A. At this time, EPA is 

unaware of any recovery units that are designed specifically for recovering hydrocarbons and which are 

readily available in the U.S. Further, we are not aware of relevant U.S. standards for such recovery units. 

However, to the extent that these hydrocarbons are recovered rather than vented as would be allowed in 

the specified end-uses if this proposal became final, EPA recommends the use of recovery equipment 

designed for flammable refrigerants, when such equipment and relevant U.S. standards for it become 

available, in accordance with applicable safe handling practices.

E. What is EPA proposing regarding venting, release, or disposal of refrigerant substitutes, 

other than hydrocarbons, included in our proposed decision?

Today’s proposed rulemaking would regulate the use of HFC-32 in room AC units. All HFCs are 

currently subject to the venting prohibition. EPA is not proposing to extend the exemption to HFC-32 or 

any refrigerant blends that contain HFC-32 or any other HFC. Further, the exemption to the venting 

prohibition proposed in this NPRM does not extend to blends of hydrocarbons and other types of 

compounds, e.g., blends of HFCs and hydrocarbons. Such refrigerant substitutes would still be subject to 

the statutory and regulatory venting prohibition.

VII. What recommendations does EPA have for safe use of the proposed flammable

substitute refrigerants?

EPA recommends that only technicians specifically trained in handling flammable refrigerant 

substitutes service or dispose of refrigeration and air conditioning equipment containing these substances. 

Technicians should know how to minimize the risk of fire and the procedures for using flammable 

refrigerant substitutes safely. Releases of large quantities of refrigerant substitutes during servicing and

manufacturing, especially in enclosed, poorly ventilated spaces or in areas where large amounts of 

refrigerant are stored, could cause an explosion if an ignition source exists nearby. For these reasons, it is 
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important that only properly trained technicians handle flammable refrigerant substitutes when 

maintaining, servicing, repairing, or disposing of household and retail food refrigerators and freezers, very

low temperature freezers, non-mechanical heat transfer equipment (e.g., thermosiphons), and room air 

conditioners. In addition, EPA recommends that if hydrocarbon refrigerant substitutes were vented, 

released, or disposed of (rather than recovered), as would be allowed in the specified end-uses if this 

proposal became final, the release should be in a well-ventilated area, such as outside of a building.

We are aware that at least one organization, Refrigeration Service Engineers Society (RSES), has 

developed a technician training program in collaboration with refrigeration equipment manufacturers and 

users that addresses safe use of flammable refrigerant substitutes. In addition, EPA has reviewed several 

training programs provided as part of SNAP submissions from persons interested in flammable refrigerant

substitutes. EPA intends to update the CAA Section 608 technician certification test bank provided to 

approved organizations that administer the certification exams in accordance with 40 CFR 82.161 to 

specifically include questions concerning flammable refrigerant substitutes. 

EPA considered proposing a use condition requiring training in handling flammable refrigerant 

substitutes for technicians who service or dispose of refrigeration and air conditioning equipment 

containing these substitutes. However, we do not have sufficient information on the core elements that 

should be part of such a training program to ensure that a training requirement would improve safety. 

Some examples of potential core elements that EPA might consider include:

 EPA’s relevant use conditions for flammable refrigerants ; 

 relevant OSHA requirements for flammable gases; relevant industry standards (e.g., UL, ASHRAE, 

NFPA); 

 MSDS information, including first aid and physical and chemical characteristics of flammable 

refrigerants; and 

 requirements and procedures for safe storage and handling of flammable refrigerants.

EPA requests comment on whether we should establish a use condition requiring training in handling 
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flammable refrigerant substitutes for technicians servicing or disposing of equipment containing such 

substitutes, and if so, what should be the mandatory elements of such training.

VIII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: 

Improving Regulation and Regulatory Review

Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is a “significant 

regulatory action.” It raises novel legal or policy issues arising out of legal mandates, the President’s 

priorities, or the principles set forth in the Executive Order. Accordingly, EPA submitted this action to the 

Office of Management and Budget (OMB) for review under EO 12866 and 13563 (76 FR 3821, January

21, 2011) and any changes made in response to OMB recommendations have been documented in the 

docket for this action.

B. Paperwork Reduction Act

This action does not impose any new information collection burden. This proposed rule is an 

Agency determination. It contains no new requirements for reporting or recordkeeping. The Office of 

Management and Budget (OMB) has previously approved the information collection requirements 

contained in the existing regulations in Subpart G of 40 CFR Part 82 under the provisions of the 

Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and has assigned OMB control number 2060-0226.

This Information Collection Request (ICR) included five types of respondent reporting and recordkeeping 

activities pursuant to SNAP regulations: submission of a SNAP petition, filing a SNAP/TSCA 

Addendum, notification for test marketing activity, recordkeeping for substitutes acceptable subject to use 

restrictions, and recordkeeping for small volume uses. The OMB control numbers for EPA’s regulations 

are listed in 40 CFR Part 9 and 48 CFR Chapter 15.C.

C. Regulatory Flexibility Act

The Regulatory Flexibility Act (RFA) generally requires an agency to prepare a regulatory 

flexibility analysis of any rule subject to notice and comment rulemaking requirements under the 
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Administrative Procedure Act or any other statute unless the agency certifies that the rule will not have a 

significant economic impact on a substantial number of small entities. Small entities include small 

businesses, small organizations, and small governmental jurisdictions. For purposes of assessing the 

impacts of this rule on small entities, small entity is defined as: (1) a small business as defined by the 

Small Business Administration’s (SBA) regulations at 13 CFR 121.201; (2) a small governmental 

jurisdiction that is a government of a city, county, town, school district or special district with a 

population of less than 50,000; and (3) a small organization that is any not-for-profit enterprise which is 

independently owned and operated and is not dominant in its field.

After considering the economic impacts of this proposed rule on small entities, I certify that this 

action will not have a significant economic impact on a substantial number of small entities. In

determining whether a rule has a significant economic impact on a substantial number of small entities, 

the impact of concern is any significant adverse economic impact on small entities, since the primary

purpose of the regulatory flexibility analyses is to identify and address regulatory alternatives “which 

minimize any significant economic impact of the rule on small entities.” 5 U.S.C. 603 and 604. Thus, an 

agency may certify that a rule will not have a significant economic impact on a substantial number of 

small entities if the rule relieves regulatory burden, or otherwise has a positive economic effect on all of 

the small entities subject to the rule. The use conditions of this proposed rule, if finalized, would apply to 

manufacturers of household and commercial refrigerators and freezers, vending machines, nonmechanical heat transfer equipment, very low temperature refrigeration equipment for laboratories and 

room air conditioners that choose to use these refrigerants. Today’s action, if finalized, would allow 

equipment manufacturers the additional options of using ethane, HFC-32, isobutane, propane, and R441A in the specified end-uses but does not mandate such use. Because refrigeration and air conditioning 

equipment for these refrigerants are not manufactured yet in the U.S. for the proposed end-uses (with the 

exception of limited test-marketing), no change in business practice would be required to meet the use 

conditions, resulting in no adverse impact compared to the absence of this rule. Proposed provisions that 
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would allow venting of hydrocarbon refrigerants in the uses addressed by this rule would reduce 

regulatory burden. Thus, the rule would not impose any new costs on small entities if finalized as 

proposed. EPA continues to be interested in the potential impacts of the proposed rule on small entities 

and welcomes comments on issues related to such impacts.

D. Unfunded Mandates Reform Act

This action contains no Federal mandates under the provisions of Title II of the Unfunded 

Mandate Reform Act of 1995 (UMRA), 2 U.S.C. 1531–1538 for State, local, or tribal governments or the 

private sector. This action imposes no enforceable duty on any State, local, or tribal governments or the 

private sector. The enforceable requirements of this proposed rule related to integrating risk mitigation 

devices, markings, and procedures for maintaining safety of refrigeration and air conditioning equipment 

using flammable refrigerants affect only a small number of manufacturers of refrigeration and air 

conditioning equipment and their technicians. Therefore, this rule is not subject to the requirements of 

sections 202 and 205 of the UMRA. This action is also not subject to the requirements of section 203 of 

UMRA because it contains no regulatory requirements that might significantly or uniquely affect small 

governments. This regulation applies equipment manufacturers and not to governmental entities. Today’s 

action, if finalized, would allow equipment manufacturers the additional options of using ethane, HFC-32,

isobutane, propane, and R-441A in the specified end-uses. Because refrigeration and air conditioning 

equipment for these refrigerants are not manufactured yet in the U.S. for the proposed end-uses, no 

change in business practice would be required to meet the use conditions. This proposed rule does not 

mandate a switch to these substitutes; consequently, there is no direct economic impact on entities from 

this rulemaking.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have substantial direct effects on the 

States, on the relationship between the national government and the States, or on the distribution of power 

and responsibilities among the various levels of government, as specified in Executive Order 13132. This
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regulation applies directly to facilities that use these substances and not to governmental entities. Thus, 

Executive Order 13132 does not apply to this action. In the spirit of Executive Order 13132, and

consistent with EPA policy to promote communications between EPA and State and local governments, 

EPA specifically solicits comments on this proposed action from State and local officials.

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

This action does not have tribal implications, as specified in Executive Order 13175 (65 FR 

67249, November 9, 2000). It will not have substantial direct effects on tribal governments, on the 

relationship between the Federal government and Indian tribes, or on the distribution of power and 

responsibilities between the Federal government and Indian tribes, as specified in Executive Order 13175.

EPA specifically solicits additional comment on this proposed action from tribal officials.

G. Executive Order 13045: Protection of Children From Environmental Health and Safety 

Risks

This action is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it is 

not economically significant as defined in EO 12866, and because the Agency does not believe the 

environmental health or safety risks addressed by this action present a disproportionate risk to children. 

This proposed rule provides both regulatory restrictions and recommended guidelines based upon risk 

screens conducted in order to reduce risk of fire and explosion. This proposed rule, if finalized, would 

provide refrigerant substitutes that have no ODP and lower GWP than other substitutes currently listed as 

acceptable. The reduction in ODS and GHG emissions would assist in restoring the stratospheric ozone 

layer and provide climate benefits. The public is invited to submit comments or identify peer-reviewed 

studies and data that assess effects of early life exposure to the refrigerant substitutes addressed in this

action.

H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or 

Use

This action is not a “significant energy action” as defined in Executive Order 13211, (66 FR 
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28355 (May 22, 2001)) because it is not likely to have a significant adverse effect on the supply, 

distribution, or use of energy. Preliminary information indicates that these new systems may be more

energy efficient than currently available systems in some climates. 

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (“NTTAA”), 

Public Law 104–113, (15 U.S.C. 272 note) directs EPA to use voluntary consensus standards in its 

regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical. 

Voluntary consensus standards are technical standards (e.g., materials specifications, test methods, 

sampling procedures, and business practices) that are developed or adopted by voluntary consensus 

standards bodies. The NTTAA directs EPA to provide Congress, through OMB, explanations when the

Agency decides not to use available and applicable voluntary consensus standards. This proposed rule

involves technical standards. EPA proposes to use current editions of the Underwriters Laboratories (UL)

standards 250, 471, 541 and 484, which include requirements for safety and reliability for flammable 

refrigerants. This proposed rule regulates the safety and deployment of new substitutes for household and

commercial refrigerators and freezers, vending machines, non-mechanical heat transfer equipment, very

low temperature refrigeration equipment, and room air conditioners. 

EPA welcomes comment on this aspect of the proposed rulemaking and, specifically invites the

public to identify potentially applicable voluntary consensus standards and to explain why such standards 

should be used in this regulation.

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority 

Populations and Low-Income Populations

Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes Federal executive policy on 

environmental justice. Its main provision directs Federal agencies, to the greatest extent practicable and 

permitted by law, to make environmental justice part of their mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or environmental effects of their programs, 
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policies, and activities on minority populations and low-income populations in the United States.

EPA has determined that this proposed rule will not have disproportionately high and adverse 

human health or environmental effects on minority or low-income populations because it increases the 

level of human health and environmental protection for all affected populations without having any 

disproportionately high and adverse human health or environmental effects on any population, including 

any minority or low-income population. This proposed rule, if finalized, would provide refrigerant 

substitutes that have no ODP and lower GWP than other substitutes currently listed as acceptable. The 

reduction in ODS and GHG emissions would assist in restoring the stratospheric ozone layer and provide

climate benefits.

IX. References

This preamble references the following documents, which are also in the Air Docket at the address 

listed in Section I.B.1. Unless specified otherwise, all documents are available electronically through the 

Federal Docket Management System, Docket # EPA-HQ-OAR-2013-0748.

Air-Conditioning, Heating, and Refrigeration Institute (AHRI), 2012. AHRI Guideline N-2012: 

Assignment of Refrigerant Container Colors. 2012.

ASHRAE, 2010. American National Standards Institute (ANSI)/American Society of Heating, 

Refrigerating and Air-Conditioning Engineers (ASHRAE). Standard 34-2010 (supersedes 

ANSI/ASHRAE Standard 34-2007): Designation and Safety Classification of Refrigerants. 2010.

A.S. Trust & Holdings, 2012. Significant New Alternatives Policy Program Submission to the 

United States Environmental Protection Agency for R-441A in retail food refrigeration.

A/S Vestfrost, 2012. Significant New Alternatives Policy Program Submission to the United 

States Environmental Protection Agency for isobutane in retail food refrigeration.

Climate Action Plan (CAP), 2013. The President’s Climate Action Plan. Executive Office of the 

President. June, 2013. Available online at 

www.whitehouse.gov/sites/default/files/image/president27sclimateactionplan.pdf.

Chinese Household Electrical Appliance Association (CHEAA), 2013. Significant New 

Alternatives Policy Program Submission to the United States Environmental Protection Agency for 

Propane (R-290) in residential and light commercial air conditioning and dehumidifiers. Daikin, 2011. 

Significant New Alternatives Policy Program Submission to the United States Environmental Protection 

Agency for HFC-32 in residential and light commercial air conditioning.

EPA, 2013. Derivation of Charge Limits for Room Air Conditioners. Staff memo to Air Docket. 

2013.

ICF, 2013a. Assessment of the Potential Impact of Hydrocarbon Refrigerants on Ground-Level 

Ozone Concentrations.

ICF, 2013b. Risk Screen on Substitutes for CFC-12, HCFC-22 and R-502 in Retail Food 

Refrigeration; Substitute: Isobutane (R-600a)
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ICF, 2013c. Risk Screen on Substitutes for CFC-12, HCFC-22 and R-502 in Retail Food 

Refrigeration; Substitute: R-441A

ICF, 2013d. Risk Screen on Substitute for CFC-12, CFC-13, R-13B1, and R-503 in Very Low 

Temperature Refrigeration and Non-Mechanical Heat Transfer; Substitute: Ethane (R-170)

ICF, 2013e. Risk Screen on Substitutes for CFC-12 and R-502 in Vending Machines; Substitute: 

R-441A

ICF, 2013f. Risk Screen on Substitutes for CFC-12 and R-502 in Vending Machines; Substitute: 

Isobutane (R-600a)

ICF, 2013g. Risk Screen on Substitutes for CFC-12 and R-502 in Vending Machines; Substitute: 

R-290 (Propane)

ICF, 2013h. Risk Screen on Substitutes for CFC-12 and HCFC-22 in Household Refrigerators and 

Household Freezers.; Substitute: Propane (R-290).

ICF, 2013i. Risk Screen on Substitutes for HCFC-22 in Residential and Light Commercial Air 

Conditioning and Heat Pumps; Substitute: R-290 (Propane)

ICF, 2013j. Risk Screen on Substitutes for HCFC-22 in Residential and Light Commercial Air 

Conditioning and Heat Pumps; Substitute: HFC-32 (Difluoromethane)

ICF, 2013k.Risk Screen on Substitutes for HCFC-22 in Residential and Light Commercial Air 

Conditioning and Heat Pumps; Substitute: R-441A

IPCC, 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I 

to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. 

Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge 

University Press, Cambridge, United Kingdom and New York, NY, USA. This document is accessible at 

www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html

Montzka, S.A., 2012. HFCs in the Atmosphere: Concentrations, Emissions and Impacts, 

ASHRAE/NIST Conference 2012.

NOAA, 2013. NOAA emissions data on HFCs. Available online at 

ftp://ftp.cmdl.noaa.gov/hats/hfcs/.

ORNL, 1997. J. Sand, S. Fischer, and V. Baxter, “Energy and Global Warming Impacts of HFC 

Refrigerants and Emerging Technologies,” 1997, Oak Ridge National Lab.

Sheldon, 1989. Sheldon, L.S., et al. 1989. "An Investigation of Infiltration and Indoor Air 

Quality." New York State Energy Research & Development Authority, Report 90-11. As cited in ICF, 

2013h, Risk screen for propane in household refrigerators and freezers.

Underwriters Laboratories (UL), 2000. UL 250: Household Refrigerators and Freezers. 10th

edition. Supplement SA: Requirements for Refrigerators and Freezers Employing a Flammable 

Refrigerant in the Refrigerating System. August 2000.

UL, 2010. UL 471. Commercial Refrigerators and Freezers. 10th edition. Supplement SB: 

Requirements for Refrigerators and Freezers Employing a Flammable Refrigerant in the Refrigerating 

System. November 2010.

UL, 2011. UL 541. Refrigerated Vending Machines. 7th edition. Supplement SA: Requirements for 

Room Air Conditioners Employing a Flammable Refrigerant in the Refrigerating System. December 

2011.

UL, 2012. UL 484. Room Air Conditioners. 8th edition. Supplement SA: Requirements for 

Refrigerated Venders Employing a Flammable Refrigerant in the Refrigerating System. August 2012.
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Protection of Stratospheric Ozone: Listing of Substitutes for Refrigeration and Air Conditioning 

and Revision of the Venting Prohibition for Certain Refrigerant Substitutes

Proposed Rule

Page 73 of 87

List of Subjects in 40 CFR Part 82

Environmental protection, Administrative practice and procedure, Air pollution control, 

Incorporation by reference, Recycling, Reporting and recordkeeping requirements, Stratospheric ozone 

layer.

DATED:

Gina McCarthy, 

Administrator.
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For the reasons stated in the preamble, 40 CFR part 82 is proposed to be amended as follows:

PART 82 - PROTECTION OF STRATOSPHERIC OZONE

1. The authority citation for part 82 continues to read as follows:

Authority: 42 U.S.C. 7414, 7601, 7671 - 7671q.

Subpart G – Significant New Alternatives Policy Program

2. Subpart G is amended by revising Appendix R to read as follows:

Appendix R to subpart G of part 82- Substitutes Subject to Use Restrictions Listed in the December 20, 

2011, final rule, Effective February 21, 2012, and in the [INSERT DATE OF PUBLICATION OF 

FINAL RULE IN THE FEDERAL REGISTER] final rule, Effective [INSERT DATE 60 DAYS 

AFTER PUBLICATION OF FINAL RULE IN THE FEDERAL REGISTER].
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SUBSTITUTES THAT ARE ACCEPTABLE SUBJECT TO USE CONDITIONS

End-use Substitute Decision Use Conditions Further Information

Household 

refrigerators,

freezers, and 

combination 

refrigerators 

and freezers

(New 

equipment 

only)

Isobutane 

(R-600a) 

Propane (R290)

R-441A 

Acceptable 

Subject To

Use 

Conditions 

These refrigerants may be used 

only in new equipment 

designed specifically and 

clearly identified for the 

refrigerant (i.e., none of these 

substitutes may be used as a 

conversion or “retrofit” 

refrigerant for existing 

equipment designed for a 

different refrigerant).

These refrigerants may be used 

only in a refrigerator or 

freezer, or combination 

refrigerator and freezer, that 

meets all requirements listed 

in Supplement SA to the 10th

edition of the Underwriters 

Laboratories (UL) Standard 

for Household Refrigerators 

and Freezers, UL 250, dated 

August 25, 2000. In cases 

where the final rule includes 

requirements more stringent 

than those of the 10th edition 

of UL 250, the appliance must 

meet the requirements of the 

final rule in place of the 

requirements in the UL 

Standard.

The quantity of the substitute 

refrigerant (i.e., “charge size”) 

must not exceed 57 grams 

(2.01 ounces) in any 

refrigerator, freezer, or 

combination refrigerator and 

freezer for each circuit. 

Applicable OSHA requirements at 29 CFR 

part 1910 must be followed, including 

those at 29 CFR 1910.106 (flammable 

and combustible liquids), 1910.110 

(storage and handling of liquefied 

petroleum gases), 1910.157 (portable fire 

extinguishers), and 1910.1000 (toxic and 

hazardous substances).

Proper ventilation should be maintained at all 

times during the manufacture and storage 

of equipment containing hydrocarbon 

refrigerants through adherence to good 

manufacturing practices as per 29 CFR 

1910.106. If refrigerant levels in the air 

surrounding the equipment rise above 

one-fourth of the lower flammability 

limit, the space should be evacuated and 

re-entry should occur only after the space 

has been properly ventilated.

Technicians and equipment manufacturers 

should wear appropriate personal 

protective equipment, including chemical 

goggles and protective gloves, when 

handling these refrigerants. Special care 

should be taken to avoid contact with the 

skin since these refrigerants, like many 

refrigerants, can cause freeze burns on the 

skin. 

A class B dry powder type fire extinguisher 

should be kept nearby.

Technicians should only use spark-proof 

tools when working on refrigerators and 

freezers with these refrigerants.

Any recovery equipment used should be 

designed for flammable refrigerants. 

Any refrigerant releases should be in a wellventilated area, such as outside of a 

building.

Only technicians specifically trained in 

handling flammable refrigerants should 

service refrigerators and freezers 

containing these refrigerants. Technicians 

should gain an understanding of 

minimizing the risk of fire and the steps 

to use flammable refrigerants safely.
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End-use Substitute Decision Use Conditions Further Information

Household 

refrigerators, 

freezers, and 

combination 

refrigerators 

and freezers

(New 

equipment 

only)

Isobutane 

(R-600a) 

Propane (R290)

R-441A 

Acceptable 

Subject To 

Use 

Conditions 

As provided in clauses SA6.1.1 and SA6.1.2 

of UL Standard 250, 10th edition, the following 

markings must be attached at the locations 

provided and must be permanent: 

(a) On or near any evaporators that can be 

contacted by the consumer: "DANGER- Risk 

of Fire or Explosion. Flammable Refrigerant 

Used. Do Not Use Mechanical Devices To 

Defrost Refrigerator. Do Not Puncture 

Refrigerant Tubing."

(b) Near the machine compartment: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be Repaired 

Only By Trained Service Personnel. Do Not 

Puncture Refrigerant Tubing."

(c) Near the machine compartment: 

“CAUTION - Risk of Fire or Explosion. 

Flammable Refrigerant Used. Consult Repair 

Manual/Owner's Guide Before Attempting To 

Service This Product. All Safety Precautions 

Must Be Followed."

(d) On the exterior of the refrigerator: 

“CAUTION - Risk of Fire or Explosion. 

Dispose of Properly In Accordance With 

Federal Or Local Regulations. Flammable 

Refrigerant Used."

(e) Near any and all exposed refrigerant 

tubing: “CAUTION - Risk of Fire or 

Explosion Due To Puncture Of Refrigerant 

Tubing; Follow Handling Instructions 

Carefully. Flammable Refrigerant Used."

All of these markings must be in letters no less 

than 6.4 mm (1/4 inch) high. 

The refrigerator, freezer, or combination 

refrigerator and freezer must have red, 

Pantone® Matching System (PMS) #185 

marked pipes, hoses, or other devices through 

which the refrigerant is serviced (typically 

known as the service port) to indicate the use 

of a flammable refrigerant. This color must be 

present at all service ports and where service 

puncturing or otherwise creating an opening 

from the refrigerant circuit to the atmosphere 

might be expected (e.g., process tubes). The 

color mark must extend at least 2.5 centimeters 

(1 inch) from the compressor and must be 

replaced if removed.

Room occupants should 

evacuate the space immediately 

following the accidental release 

of this refrigerant.

If a service port is added then 

household refrigerators, 

freezers, and combination 

refrigerator and freezers using 

these refrigerants should have 

service aperture fittings that 

differ from fittings used in 

equipment or containers using 

non-flammable refrigerant. 

“Differ” means that either the 

diameter differs by at least 1/16 

inch or the thread direction is 

reversed (i.e., right-handed vs. 

left-handed). These different 

fittings should be permanently 

affixed to the unit at the point 

of service and maintained until 

the end-of-life of the unit, and 

should not be accessed with an 

adaptor.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

77 of 88

End-use Substitute Decision Use Conditions Further Information

Retail food 

refrigerators 

and freezers 

(stand-alone 

units only)

(New 

equipment 

only)

Isobutane 

(R-600a)

Propane (R290) 

R-441A

Acceptable 

subject to 

use 

conditions

These refrigerants may be used only in 

new equipment specifically designed 

and clearly identified for the 

refrigerants (i.e., none of these 

substitutes may be used as a 

conversion or “retrofit” refrigerant for 

existing equipment designed for other 

refrigerants).

These substitutes may only be used in

equipment that meets all requirements 

in Supplement SB to the 10th edition 

of the Underwriters Laboratories 

(UL) Standard for Commercial 

Refrigerators and Freezers, UL 471, 

dated November 24, 2010. In cases 

where the final rule includes 

requirements more stringent than 

those of the 10th edition of UL 471, 

the appliance must meet the 

requirements of the final rule in place 

of the requirements in the UL 

Standard.

The charge size for the retail food 

refrigerator or freezer must not 

exceed 150 grams (5.29 ounces) in 

each circuit.

Applicable OSHA requirements at 29 CFR 

part 1910 must be followed, including 

those at 29 CFR 1910.94 (ventilation) and 

1910.106 (flammable and combustible 

liquids), 1910.110 (storage and handling 

of liquefied petroleum gases), and 

1910.1000 (toxic and hazardous 

substances).

Proper ventilation should be maintained at all 

times during the manufacture and storage 

of equipment containing hydrocarbon 

refrigerants through adherence to good 

manufacturing practices as per 29 CFR 

1910.106. If refrigerant levels in the air 

surrounding the equipment rise above 

one-fourth of the lower flammability 

limit, the space should be evacuated and 

re-entry should occur only after the space 

has been properly ventilated.

Technicians and equipment manufacturers 

should wear appropriate personal 

protective equipment, including chemical 

goggles and protective gloves, when 

handling these refrigerants. Special care 

should be taken to avoid contact with the 

skin since these refrigerants, like many 

refrigerants, can cause freeze burns on the 

skin. 

A class B dry powder type fire extinguisher 

should be kept nearby.

Technicians should only use spark-proof 

tools when working on refrigerators and 

freezers with these refrigerants.

Any recovery equipment used should be 

designed for flammable refrigerants. 

Any refrigerant releases should be in a wellventilated area, such as outside of a 

building.

Only technicians specifically trained in 

handling flammable refrigerants should 

service refrigerators and freezers 

containing these refrigerants. Technicians 

should gain an understanding of 

minimizing the risk of fire and the steps 

to use flammable refrigerants safely.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

78 of 88

End-use Substitute Decision Use Conditions Further Information

Retail food 

refrigerators 

and freezers 

(stand-alone 

units only)

(New 

equipment 

only)

Isobutane 

(R-600a)

Propane (R290) 

R-441A

Acceptable 

subject to 

use 

conditions

As provided in clauses SB6.1.2 to SB6.1.5 of 

UL Standard 471, 10th edition, the following 

markings must be attached at the locations 

provided and must be permanent:

(a) Attach on or near any evaporators that can 

be contacted by the consumer: "DANGERRisk of Fire or Explosion. Flammable 

Refrigerant Used. Do Not Use Mechanical 

Devices To Defrost Refrigerator. Do Not 

Puncture Refrigerant Tubing."

(b) Attach near the machine compartment: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be 

Repaired Only By Trained Service 

Personnel. Do Not Puncture Refrigerant 

Tubing."

(c) Attach near the machine compartment: 

“CAUTION - Risk of Fire or Explosion. 

Flammable Refrigerant Used. Consult 

Repair Manual/Owner's Guide Before 

Attempting To Service This Product. All 

Safety Precautions Must be Followed."

(d) Attach on the exterior of the refrigerator: 

“CAUTION - Risk of Fire or Explosion. 

Dispose of Properly In Accordance With 

Federal Or Local Regulations. Flammable 

Refrigerant Used."

(e) Attach near any and all exposed refrigerant 

tubing: “CAUTION - Risk of Fire or 

Explosion Due To Puncture Of Refrigerant 

Tubing; Follow Handling Instructions 

Carefully. Flammable Refrigerant Used."

All of these markings must be in letters no less 

than 6.4 mm (1/4 inch) high. 

The refrigerator or freezer must have red, 

Pantone® Matching System (PMS) #185 

marked pipes, hoses, and other devices 

through which the refrigerant is serviced, 

typically known as the service port, to 

indicate the use of a flammable refrigerant. 

This color must be present at all service 

ports and where service puncturing or 

otherwise creating an opening from the 

refrigerant circuit to the atmosphere might 

be expected (e.g., process tubes). The color 

mark must extend at least 2.5 centimeters (1 

inch) from the compressor and must be 

replaced if removed.

Room occupants should evacuate the 

space immediately following the 

accidental release of this 

refrigerant.

If a service port is added then retail 

food refrigerators and freezers 

using these refrigerants should 

have service aperture fittings that 

differ from fittings used in 

equipment or containers using nonflammable refrigerant. “Differ” 

means that either the diameter 

differs by at least 1/16 inch or the 

thread direction is reversed (i.e., 

right-handed vs. left-handed). 

These different fittings should be 

permanently affixed to the unit at 

the point of service and maintained 

until the end-of-life of the unit, and 

should not be accessed with an 

adaptor.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

79 of 88

End-use Substitute Decision Use Conditions Further Information

Very low 

temperature 

refrigeration

Nonmechanical 

heat transfer

(New 

equipment 

only)

Ethane (R170)Acceptable 

subject to 

use 

conditions

This refrigerant may be used only in new 

equipment specifically designed and 

clearly identified for the refrigerant 

(i.e., the substitute may not be used as 

a conversion or “retrofit” refrigerant 

for existing equipment designed for 

other refrigerants).

These substitutes may only be used in 

equipment that meets all requirements 

in Supplement SB to the 10th edition of 

the Underwriters Laboratories (UL) 

Standard for Commercial Refrigerators 

and Freezers, UL 471, dated November

24, 2010. In cases where the final rule 

includes requirements more stringent 

than those of the 10th edition of UL 

471, the appliance must meet the 

requirements of the final rule in place 

of the requirements in the UL 

Standard.

The charge size for the retail food 

refrigerator or freezer must not exceed 

150 grams (5.29 ounces) in each 

circuit.

Applicable OSHA requirements at 29 

CFR part 1910 must be followed, 

including those at 29 CFR 1910.94 

(ventilation) and 1910.106 

(flammable and combustible 

liquids), 1910.110 (storage and 

handling of liquefied petroleum 

gases), and 1910.1000 (toxic and 

hazardous substances).

Proper ventilation should be 

maintained at all times during the 

manufacture and storage of 

equipment containing hydrocarbon 

refrigerants through adherence to 

good manufacturing practices as 

per 29 CFR 1910.106. If refrigerant 

levels in the air surrounding the 

equipment rise above one-fourth of 

the lower flammability limit, the 

space should be evacuated and reentry should occur only after the 

space has been properly ventilated.

Technicians and equipment 

manufacturers should wear 

appropriate personal protective 

equipment, including chemical 

goggles and protective gloves, 

when handling ethane. Special care 

should be taken to avoid contact 

with the skin since ethane, like 

many refrigerants, can cause freeze 

burns on the skin. 

A class B dry powder type fire 

extinguisher should be kept nearby.

Technicians should only use sparkproof tools when working on 

refrigerators and freezers with 

flammable refrigerants.

Any recovery equipment used should 

be designed for flammable 

refrigerants. 

Any refrigerant releases should be in a 

well-ventilated area, such as 

outside of a building.

Only technicians specifically trained in 

handling flammable refrigerants 

should service refrigerators and 

freezers containing these 

refrigerants. Technicians should 

gain an understanding of 

minimizing the risk of fire and the 

steps to use flammable refrigerants 

safely.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

80 of 88

End-use Substitute Decision Use Conditions Further Information

Very low 

temperature 

refrigeration

Nonmechanical 

heat transfer

(New 

equipment 

only)

Ethane (R170)Acceptable 

subject to 

use 

conditions

As provided in clauses SB6.1.2 to SB6.1.5 of 

UL Standard 471, 10th edition, the following 

markings must be attached at the locations 

provided and must be permanent:

(a) Attach on or near any evaporators that can 

be contacted by the consumer: "DANGERRisk of Fire or Explosion. Flammable 

Refrigerant Used. Do Not Use Mechanical 

Devices To Defrost Refrigerator. Do Not 

Puncture Refrigerant Tubing."

(b) Attach near the machine compartment: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be 

Repaired Only By Trained Service 

Personnel. Do Not Puncture Refrigerant 

Tubing."

(c) Attach near the machine compartment: 

“CAUTION - Risk of Fire or Explosion. 

Flammable Refrigerant Used. Consult 

Repair Manual/Owner's Guide Before 

Attempting To Service This Product. All 

Safety Precautions Must be Followed."

(d) Attach on the exterior of the refrigerator: 

“CAUTION - Risk of Fire or Explosion. 

Dispose of Properly In Accordance With 

Federal Or Local Regulations. Flammable 

Refrigerant Used."

(e) Attach near any and all exposed refrigerant 

tubing: “CAUTION - Risk of Fire or 

Explosion Due To Puncture Of Refrigerant 

Tubing; Follow Handling Instructions 

Carefully. Flammable Refrigerant Used."

All of these markings must be in letters no less 

than 6.4 mm (1/4 inch) high. 

The refrigeration equipment must have red, 

Pantone® Matching System (PMS) #185 

marked pipes, hoses, and other devices 

through which the refrigerant is serviced, 

typically known as the service port, to 

indicate the use of a flammable refrigerant. 

This color must be present at all service 

ports and where service puncturing or 

otherwise creating an opening from the 

refrigerant circuit to the atmosphere might 

be expected (e.g., process tubes). The color 

mark must extend at least 2.5 centimeters (1 

inch) from the compressor and must be 

replaced if removed.

Room occupants should evacuate the 

space immediately following the 

accidental release of this 

refrigerant.

If a service port is added then 

refrigeration equipment using this 

refrigerant should have service 

aperture fittings that differ from 

fittings used in equipment or 

containers using non-flammable 

refrigerant. “Differ” means that 

either the diameter differs by at 

least 1/16 inch or the thread 

direction is reversed (i.e., righthanded vs. left-handed). These 

different fittings should be 

permanently affixed to the unit at 

the point of service and 

maintained until the end-of-life of 

the unit, and should not be 

accessed with an adaptor.

Example of non-mechanical heat 

transfer using this refrigerant 

would be use in a secondary loop 

of a thermosiphon.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

81 of 88

End-use Substitute Decision Use Conditions Further Information

Vending 

Machines

(New 

equipment 

only)

Isobutane (R600a)

Propane (R290)

R-441A

Acceptable 

subject to 

use 

conditions

These refrigerants may be used only in 

new equipment specifically designed 

and clearly identified for the 

refrigerants (i.e., none of these 

substitutes may be used as a conversion 

or “retrofit” refrigerant for existing 

equipment designed for other 

refrigerants).

Where it is possible to easily detach and 

replace the old refrigeration circuit 

from the outer casing of the equipment. 

with a new one containing a new 

evaporator, condenser and refrigerant 

tubing within the old casing , this is 

considered “new” equipment and not a 

retrofit of the old, existing equipment.

These substitutes may only be used in 

equipment that meets all requirements 

in Supplement SA to the 7th edition of

the Underwriters Laboratories (UL) 

Standard for Refrigerated Vending 

Machines, UL 541, dated December, 

2011. In cases where the final rule 

includes requirements more stringent 

than those of the 7

th edition of UL 541, 

the appliance must meet the 

requirements of the final rule in place 

of the requirements in the UL Standard.

The charge size for the refrigeration 

equipment shall not exceed 150 grams 

(5.29 ounces) in each circuit.

Applicable OSHA requirements at 29 

CFR part 1910 must be followed, 

including those at 29 CFR 1910.94 

(ventilation) and 1910.106 

(flammable and combustible 

liquids), 1910.110 (storage and 

handling of liquefied petroleum 

gases), and 1910.1000 (toxic and 

hazardous substances).

Proper ventilation should be 

maintained at all times during the 

manufacture and storage of 

equipment containing hydrocarbon 

refrigerants through adherence to 

good manufacturing practices as 

per 29 CFR 1910.106. If refrigerant 

levels in the air surrounding the 

equipment rise above one-fourth of 

the lower flammability limit, the 

space should be evacuated and reentry should occur only after the 

space has been properly ventilated.

Technicians and equipment 

manufacturers should wear 

appropriate personal protective 

equipment, including chemical 

goggles and protective gloves, 

when handling propane. Special 

care should be taken to avoid 

contact with the skin since ethane, 

like many refrigerants, can cause 

freeze burns on the skin. 

A class B dry powder type fire 

extinguisher should be kept nearby.

Technicians should only use sparkproof tools when working on 

refrigeration equipment with 

flammable refrigerants.

Any recovery equipment used should 

be designed for flammable 

refrigerants. 

Any refrigerant releases should be in a 

well-ventilated area, such as 

outside of a building.

Only technicians specifically trained in 

handling flammable refrigerants 

should service refrigeration 

equipment containing this 

refrigerant. Technicians should 

gain an understanding of 

minimizing the risk of fire and the 

steps to use flammable refrigerants 

safely.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

82 of 88

End-use Substitute Decision Use Conditions Further Information

Vending 

Machines

(New 

equipment only)

Isobutane 

(R-600a)

Propane (R290)

R-441A

Acceptable 

subject to use 

conditions

As provided in clauses SA6.1.2 to SA6.1.5 

of UL Standard 541, 7

th edition, the 

following markings must be attached at 

the locations provided and must be 

permanent:

(a) Attach on or near any evaporators that 

can be contacted by the consumer: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. Do Not 

Use Mechanical Devices To Defrost 

Refrigerator. Do Not Puncture 

Refrigerant Tubing."

(b) Attach near the machine compartment: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be 

Repaired Only By Trained Service 

Personnel. Do Not Puncture Refrigerant 

Tubing."

(c) Attach near the machine compartment: 

“CAUTION - Risk of Fire or Explosion. 

Flammable Refrigerant Used. Consult 

Repair Manual/Owner's Guide Before 

Attempting To Service This Product. All 

Safety Precautions Must be Followed."

(d) Attach on the exterior of the refrigerator: 

“CAUTION - Risk of Fire or Explosion. 

Dispose of Properly In Accordance With 

Federal Or Local Regulations. 

Flammable Refrigerant Used."

(e) Attach near any and all exposed 

refrigerant tubing: “CAUTION - Risk of 

Fire or Explosion Due To Puncture Of 

Refrigerant Tubing; Follow Handling 

Instructions Carefully. Flammable 

Refrigerant Used."

All of these markings must be in letters no 

less than 6.4 mm (1/4 inch) high. 

The refrigeration equipment must have red, 

Pantone® Matching System (PMS) #185 

marked pipes, hoses, and other devices 

through which the refrigerant is serviced, 

typically known as the service port, to 

indicate the use of a flammable refrigerant. 

This color must be present at all service 

ports and where service puncturing or 

otherwise creating an opening from the 

refrigerant circuit to the atmosphere might 

be expected (e.g., process tubes). The color 

mark must extend at least 2.5 centimeters (1 

inch) from the compressor and must be 

replaced if removed.

Room occupants should evacuate the 

space immediately following the 

accidental release of this 

refrigerant.

If a service port is added then 

refrigeration equipment using 

this refrigerant should have 

service aperture fittings that 

differ from fittings used in 

equipment or containers using 

non-flammable refrigerant. 

“Differ” means that either the 

diameter differs by at least 1/16 

inch or the thread direction is 

reversed (i.e., right-handed vs. 

left-handed). These different 

fittings should be permanently 

affixed to the unit at the point of 

service and maintained until the 

end-of-life of the unit, and 

should not be accessed with an 

adaptor.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

83 of 88

End-use Substitute Decision Use Conditions Further Information

Residential and 

lightcommercial air 

conditioning 

and heat 

pumps—selfcontained room 

air conditioners 

only

(New 

equipment 

only)

HFC-32

Propane (R290)

R-441A

Acceptable 

subject to 

use 

conditions

These refrigerants may be used only 

in new equipment specifically 

designed and clearly identified for 

the refrigerants (i.e., none of these 

substitutes may be used as a 

conversion or “retrofit” refrigerant 

for existing equipment designed 

for other refrigerants).

These substitutes may only be used in 

equipment that meets all 

requirements in Supplement SA 

and Appendixes B through F of

the 8th edition of the Underwriters 

Laboratories (UL) Standard for 

Room Air Conditioners, UL 484, 

dated August 3, 2012. In cases 

where the final rule includes 

requirements more stringent than 

those of the 8th edition of UL 484, 

the appliance must meet the 

requirements of the final rule in 

place of the requirements in the 

UL Standard.

The charge size for the entire air 

conditioner must not exceed the 

maximum refrigerant mass 

determined according to 

Appendix F of UL 484, 8th edition 

for the room size where the air 

conditioner is used. The charge 

size for these three refrigerants 

must in no case exceed 7979 g 

(281.5 oz or 17.59 lb) of HFC-32; 

986 g (34.8 oz or 2.17 lbs) of 

propane; or 1000 g (35.3 oz or 

2.21 lb) of R-441A. The 

manufacturer must design a 

charge size for the entire air 

conditioner that does not exceed 

the amount specified for the unit’s 

cooling capacity, as specified in 

Table A, B, C, or D of this 

appendix

Applicable OSHA requirements at 29 

CFR part 1910 must be followed, 

including those at 29 CFR 1910.94 

(ventilation) and 1910.106 

(flammable and combustible 

liquids), 1910.110 (storage and 

handling of liquefied petroleum 

gases), and 1910.1000 (toxic and 

hazardous substances).

Proper ventilation should be 

maintained at all times during the 

manufacture and storage of 

equipment containing hydrocarbon 

refrigerants through adherence to 

good manufacturing practices as 

per 29 CFR 1910.106. If refrigerant 

levels in the air surrounding the 

equipment rise above one-fourth of 

the lower flammability limit, the 

space should be evacuated and reentry should occur only after the 

space has been properly ventilated.

Technicians and equipment 

manufacturers should wear 

appropriate personal protective 

equipment, including chemical 

goggles and protective gloves, 

when handling propane. Special 

care should be taken to avoid 

contact with the skin since propane, 

like many refrigerants, can cause 

freeze burns on the skin. 

A class B dry powder type fire 

extinguisher should be kept nearby.

Technicians should only use sparkproof tools when working on air 

conditioning equipment with 

flammable refrigerants.

Any recovery equipment used should 

be designed for flammable 

refrigerants. 

Any refrigerant releases should be in a 

well-ventilated area, such as 

outside of a building.

Only technicians specifically trained in 

handling flammable refrigerants 

should service refrigeration 

equipment containing this 

refrigerant. Technicians should 

gain an understanding of 

minimizing the risk of fire and the 

steps to use flammable refrigerants 

safely.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

84 of 88

End-use Substitute Decision Use Conditions Further Information

Residential and 

lightcommercial air 

conditioning 

and heat 

pumps—selfcontained room 

air conditioners 

only

(New 

equipment 

only)

HFC-32

Propane (R290)

R-441A

Acceptable 

subject to 

use 

conditions

As provided in clauses SA6.1.2 to SA6.1.5 of UL 

484, 8th edition, the following markings must 

be attached at the locations provided and 

must be permanent:

(a) On the outside of the air conditioner: 

"DANGER- Risk of Fire or Explosion. 

Flammable Refrigerant Used. To Be 

Repaired Only By Trained Service Personnel. 

Do Not Puncture Refrigerant Tubing."

(b) On the outside of the air conditioner: 

“CAUTION - Risk of Fire or Explosion. 

Dispose of Properly In Accordance With 

Federal Or Local Regulations. Flammable 

Refrigerant Used."

(c) On the inside of the air conditioner near the 

compressor: “CAUTION - Risk of Fire or 

Explosion. Flammable Refrigerant Used. 

Consult Repair Manual/Owner's Guide 

Before Attempting To Service This Product. 

All Safety Precautions Must be Followed."

(d) On the outside of each portable air 

conditioner: “WARNING: Appliance hall be 

installed, operated and stored in a room with 

a floor area larger the “X” m2(Y ft2).” The 

value “X” on the label must be determined 

using the minimum room size in m2

calculated using Appendix F of UL 484, 8th

edition. For R-441A, use a lower 

flammability limit of 0.041 kg/m3in 

calculations in Appendix F of UL 484, 8th

edition.

(e) All of these markings must be in letters no 

less than 6.4 mm (1/4 inch) high. 

The air conditioning equipment must have red, 

Pantone® Matching System (PMS) #185 

marked pipes, hoses, and other devices 

through which the refrigerant is serviced, 

typically known as the service port, to 

indicate the use of a flammable refrigerant. 

This color must be present at all service ports 

and where service puncturing or otherwise 

creating an opening from the refrigerant 

circuit to the atmosphere might be expected 

(e.g., process tubes). The color mark must 

extend at least 2.5 centimeters (1 inch) from 

the compressor and must be replaced if 

removed.

Room occupants should evacuate 

the space immediately 

following the accidental 

release of this refrigerant.

If a service port is added then air 

conditioning equipment using 

this refrigerant should have 

service aperture fittings that 

differ from fittings used in 

equipment or containers using 

non-flammable refrigerant. 

“Differ” means that either the 

diameter differs by at least 

1/16 inch or the thread 

direction is reversed (i.e., 

right-handed vs. left-handed). 

These different fittings should 

be permanently affixed to the 

unit at the point of service and 

maintained until the end-oflife of the unit, and should not 

be accessed with an adaptor.

Air conditioning equipment in this 

category includes:

Window air conditioning units

Portable room air conditioners

Packaged terminal air 

conditioners and heat pumps
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

85 of 88

Note: The use conditions in this appendix contain references to certain standards from Underwriters Laboratories Inc. (UL). The 

standards are incorporated by reference, and the referenced sections are made part of the regulations in part 82:

1. UL 250: Household Refrigerators and Freezers. 10th edition. Supplement SA: Requirements for Refrigerators and Freezers 

Employing a Flammable Refrigerant in the Refrigerating System. Underwriters Laboratories, Inc. August 25, 2000.

2. UL 471. Commercial Refrigerators and Freezers. 10th edition. Supplement SB: Requirements for Refrigerators and Freezers 

Employing a Flammable Refrigerant in the Refrigerating System. Underwriters Laboratories, Inc. November 24, 2010.

3. UL 541. Refrigerated Vending Machines. 7th edition. Supplement SA: Requirements for Room Air Conditioners Employing a 

Flammable Refrigerant in the Refrigerating System. December 30, 2011

4. UL 484. Room Air Conditioners. 8th edition. Supplement SA: Requirements for Refrigerated Venders Employing a Flammable 

Refrigerant in the Refrigerating System and Appendixes B through F. August 3, 2012.

The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 

51. Copies of UL Standards 250, 471, 484 and 541 may be purchased by mail at: COMM 2000; 151 Eastern Avenue; Bensenville, IL 

60106; Email: orders@comm-2000.com; Telephone: 1-888-853-3503 in the U.S. or Canada (other countries dial +1-415-352-2168); 

Internet address: http://ulstandardsinfonet.ul.com/ or www.comm-2000.com.

You may inspect a copy at U.S. EPA’s Air and Radiation Docket; EPA West Building, Room 3334, 1301 Constitution Ave., N.W., 

Washington DC or at the National Archives and Records Administration (NARA). For questions regarding access to these standards, the 

telephone number of EPA’s Air and Radiation Docket is 202-566-1742. For information on the availability of this material at NARA, 

call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

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Table A Maximum Design Charge Sizes for Window Air Conditioners

Refrigerant

Maximum design charge size (kg)

Associated cooling capacity (BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 1.73 2.12 2.74 3.00 3.24 3.47 3.68 4.07 4.59 5.48 6.01 6.49 6.72 7.76

R-290 0.13 0.16 0.20 0.22 0.24 0.26 0.27 0.30 0.34 0.40 0.44 0.48 0.50 0.57

R-441A 0.14 0.17 0.22 0.24 0.26 0.28 0.30 0.33 0.37 0.44 0.49 0.53 0.54 0.63

Note: For use with self-contained air conditioning units or heat pumps with an evaporator at least 0.6 and no more than 1.0 m above the floor. Cooling 

capacities between those in the table are to be linearly interpolated between the next smaller and larger capacities listed in the table.

Table B. Maximum Design Charge Sizes for Packaged Terminal Air Conditioners, 

Packaged Terminal Heat Pumps, and Portable Air Conditioning Units

Refrigerant

Maximum design charge size (kg)

Associated cooling capacity (BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 1.04 1.27 1.65 1.80 1.95 2.08 2.21 2.44 2.75 3.29 3.60 3.89 4.03 4.65

R-290 0.08 0.09 0.12 0.13 0.14 0.15 0.16 0.18 0.20 0.24 0.27 0.29 0.30 0.34

R-441A 0.08 0.10 0.13 0.15 0.16 0.17 0.18 0.20 0.22 0.27 0.29 0.32 0.33 0.38

Note: For use with self-contained air conditioning units or heat pumps with an evaporator no more than 0.6 m above the floor. Cooling capacities between 

those in the table are to be linearly interpolated between the next smaller and larger capacities listed in the table.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

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Table C. Maximum Design Charge Sizes for Wall-Mounted AC Units 

Refrigerant

Maximum Design Charge Size (kg)

Associated capacity (BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 3.12 3.82 4.94 5.41 5.84 6.24 6.62 7.32 8.26 9.87 10.81 11.68 12.09 13.96

R-290 0.23 0.28 0.36 0.40 0.43 0.46 0.49 0.54 0.61 0.73 0.80 0.86 0.89 1.00

R-441A 0.25 0.31 0.40 0.44 0.47 0.51 0.54 0.59 0.67 0.80 0.88 0.95 0.98 1.00

Note: For use with self-contained air conditioners or heat pumps with an evaporator at least 1.0 and no more than 1.8 m above the floor. Cooling capacities 

between those in the table are to be linearly interpolated between the next smaller and larger capacities listed in the table.

Table D. Maximum Design Charge Sizes for Ceiling-Mounted AC Units: 

Refrigerant

Maximum Design Charge Size (kg)

Associated capacity (BTU/hr)

5,000 6,000 7,000 8,000 9,000 10,000 12,000 14,000 18,000 21,000 23,000 24,000 30,000 34,000

R-32 3.82 4.67 6.03 6.61 7.14 7.63 8.09 8.95 10.09 12.07 13.22 14.28 14.78 17.06

R-290 0.28 0.34 0.44 0.49 0.53 0.56 0.60 0.66 0.74 0.89 0.97 1.00 1.00 1.00

R-441A 0.31 0.38 0.49 0.54 0.58 0.62 0.66 0.73 0.82 0.98 1.00 1.00 1.00 1.00

Note: For use with self-contained air conditioners or heat pumps with an evaporator more than 1.8 m above the floor. Cooling capacities between those in the 

table are to be linearly interpolated between the next smaller and larger capacities listed in the table.
*** E.O. 12866/13563 Review –Revised Version – Do Not Cite, Quote, or Release During Review***

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3. Amend Section 82.154 by adding section viii to paragraph (a)(1) to read as follows:

§ 82.154 Prohibitions.

(a)(1) * * *

(viii) Effective [INSERT DATE 60 DAYS AFTER PUBLICATION OF FINAL RULE IN 

THE FEDERAL REGISTER], isobutane (R-600a) and R-441A as substitutes in retail food 

refrigerators and freezers (stand-alone units only); propane (R-290) as a substitute in household 

refrigerators, freezers, and combination refrigerators and freezers; ethane (R-170) as a substitute 

in very low temperature refrigeration equipment and equipment for non-mechanical heat 

transfer; R-441A, propane and isobutane as substitutes in vending machines; and propane, and 

R-441A in self-contained room air conditioners for residential and light commercial air 

conditioning and heat pumps.

* * * * *