```

[Federal Register Volume 89, Number 238 (Wednesday, December 11, 2024)]
[Rules and Regulations]
[Pages 99720-99727]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28307]

[[Page 99720]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82

[EPA-HQ-OAR-2003-0118; FRL-12145-01-OAR]
RIN 2060-AG12

Protection of Stratospheric Ozone: Determination 39 for the 
Significant New Alternatives Policy Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Determination of acceptability.

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SUMMARY: This determination of acceptability expands the list of 
acceptable substitutes pursuant to the U.S. Environmental Protection 
Agency's Significant New Alternatives Policy program. This action lists 
four substitutes as acceptable additional substitutes for use in the 
refrigeration and air conditioning and foam blowing sectors.

DATES: This determination is applicable on December 11, 2024.

ADDRESSES: EPA established a docket for this action under Docket ID No. 
EPA-HQ-OAR-2003-0118 (continuation of Air Docket A-91-42). All 
electronic documents in the docket are listed in the index at https://www.regulations.gov. Although listed in the index, some information is 
not publicly available, e.g., confidential business information (CBI) 
or other information whose disclosure is restricted by statute. 
Publicly available docket materials are available either electronically 
at https://www.regulations.gov or in hard copy at the EPA Docket Center 
(EPA/DC), (Docket Nos. A-91-42 and EPA-HQ-OAR-2003-0118), William J. 
Clinton West, Room 3334, 1301 Constitution Avenue NW, Washington, DC 
20460. 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. The Docket Center's hours of operations are 8:30 a.m.-
4:30 p.m., Monday-Friday (except Federal Holidays). For further 
information on the EPA Docket Center services and the current status, 
please visit online at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Nathaniel Burola, Stratospheric 
Protection Division, Office of Atmospheric Protection (Mail Code 
6205A), U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue 
NW, 20460; telephone number: 202-564-2883; email address: 
[email protected].

Table of Contents

I. Listing of New Acceptable Substitutes
    A. Refrigeration and Air Conditioning
    1. R-471A
    2. R-480A
    3. R-513A
    B. Foam Blowing
    1. Extruded Polystyrene (XPS) Blowing Agent Blends of 0 to 90 
Percent HFO-1336mzz(Z), 0 to 90 Percent HFO-1234ze(E), 0 to 75 
Percent HFC-152a, and 0 to 90 Percent CO2
Appendix A: Summary of Decisions for New Acceptable Substitutes

SUPPLEMENTARY INFORMATION:

I. Listing of New Acceptable Substitutes

    This action is listing as acceptable additional substitutes for use 
in the refrigeration and air conditioning and foam blowing sectors. 
This action presents EPA's most recent decisions under the Significant 
New Alternatives Policy (SNAP) program to list as acceptable several 
substitutes in different end-uses. The new substitutes are:
     R-471A in retail food refrigeration, industrial process 
refrigeration, and cold storage warehouses (retrofit equipment only);
     R-480A in cold storage warehouses, commercial ice 
machines, positive displacement chillers, refrigerated transport, and 
water coolers (retrofit equipment only);
     R-513A in residential and light commercial air 
conditioning and heat pumps--self-contained units (new equipment only);
     XPS foam blowing agent blends of 0 to 90 percent 
hydrofluoroolefin (HFO)-1336mzz(Z), 0 to 90 percent HFO-1234ze(E), 0 to 
75 percent hydrofluorocarbon (HFC)-152a, and 0 to 90 percent carbon 
dioxide (CO2) in polystyrene: extruded boardstock and 
billet.
    Listing decisions in the end-uses in this document do not prejudge 
EPA's listings of these substitutes for other end-uses. For additional 
information on SNAP, visit the SNAP website at https://www.epa.gov/snap. The full lists of acceptable substitutes for ozone-depleting 
substances (ODS) in the industrial sectors covered by the SNAP program 
are available at https://www.epa.gov/snap/substitutes-sector. For more 
information on the Agency's process for administering the SNAP program 
or criteria for evaluation of substitutes, refer to the initial SNAP 
rulemaking (59 FR 13044; March 18, 1994). The regulations are codified 
at 40 CFR part 82, subpart G. SNAP decisions and the appropriate 
Federal Register citations are available at: https://www.epa.gov/snap/snap-regulations. Under the SNAP program, EPA may list a substitute as 
acceptable for specified end-uses where the Agency has reviewed the 
substitute and found no reason to restrict or prohibit its use. 
Substitutes listed as unacceptable; acceptable, subject to narrowed use 
limits; or acceptable, subject to use conditions are also listed in the 
appendices to 40 CFR part 82, subpart G.
    This document discusses each substitute listing in detail and 
summarizes the results of EPA's assessment of the human health and 
environmental risks posed by each substitute. EPA's evaluation applies 
the criteria in 40 CFR 82.180(a)(7), including atmospheric effects and 
related health and environmental effects, ecosystem risks, occupational 
risks, consumer risks, flammability, and cost and availability of the 
substitute. EPA evaluates these criteria in risk screens, or technical 
documents that evaluate risks to human health and the environment from 
substitutes in specific end-uses, including comparisons to other 
available substitutes and evaluations against relevant thresholds of 
risk starting with protective assumptions. The risk screens cited in 
this document include evaluation of atmospheric effects, toxicity data, 
exposure assessments, flammability, and other environmental impacts 
such as ecotoxicity and local air quality impacts. You can find more 
information on the criteria used in the evaluation of substitutes in 
the SNAP program at https://www.epa.gov/snap/snap-regulations.
    In this document, EPA determined the global warming potential (GWP) 
for a chemical or blend using the 100-year GWP values from the 
Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment 
Report (AR4) \1\ for substances or components of blends if included.\2\ 
Note that Annex F to the Montreal Protocol on Substances that Deplete 
the Ozone Layer lists GWPs for HFCs that are numerically equivalent to

[[Page 99721]]

the AR4 values.\3\ These HFC 100-year GWP values are also numerically 
equivalent to the exchange values listed in the American Innovation and 
Manufacturing Act of 2020 (hereafter referred to as ``the AIM Act''). 
If no GWP is provided in AR4 for a substance, the SNAP program is using 
the 100-year GWP listed in World Meteorological Organization (WMO), 
2022.\4\ To calculate the GWP of blends of chemicals, such as the 
listed refrigerant blends, this document weights the GWP of each 
component of the blend by its mass percentage. This method of 
calculating GWPs is consistent with the method used to calculate GWPs 
in the October 2023 Technology Transitions Rule as codified at 40 CFR 
84.64.
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    \1\ 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., Qin, D., 
Manning, M., Chen, Z., Marquis, M., Averyt, K.B., Tignor M., and 
Miller, H.L. (eds.)]. Cambridge University Press, Cambridge, United 
Kingdom and New York, NY, USA. Available at: https://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html.
    \2\ The IPCC, 2007 100-year GWP values are consistent with the 
exchange values for the regulated HFCs listed in subsection (c) of 
the AIM Act and with the GWPs in Annex F of the Montreal Protocol.
    \3\ Annex F of the Montreal Protocol is available at: https://ozone.unep.org/treaties/montreal-protocol/articles/annex-f-controlled-substances.
    \4\ WMO, Scientific Assessment of Ozone Depletion: 2022, GAW 
Report No. 278, 509 pp.; WMO: Geneva, 2022. Available at: https://ozone.unep.org/system/files/documents/Scientific-Assessment-of-Ozone-Depletion-2022.pdf. (WMO, 2022).
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    Under section 612 of the Clean Air Act (CAA), the SNAP program 
reviews substitutes using a comparative risk framework in different 
industrial sectors. In making listing decisions, EPA considers overall 
risk to human health and the environment. As a general matter, the 
substitutes being added through this action to the acceptable lists 
have a similar or lower risk than other substitutes already listed as 
acceptable in those end-uses. However, certain substitutes may have a 
higher risk than certain other substitutes already listed as acceptable 
or acceptable subject to restrictions. In such cases, those already-
listed alternatives have other factors that limit their use in some 
situations within a particular end-use.
    Appendix A contains tables summarizing each listing decision in 
this action. The statements in the ``Further Information'' column in 
the tables provide additional information, but these are not legally 
binding under section 612 of the CAA. Although users are not required 
to follow recommendations in the ``Further Information'' column of the 
table under section 612 of the CAA, some of these statements may refer 
to obligations that are enforceable or binding under federal or state 
programs other than the SNAP program. The identification of other 
enforceable or binding requirements should not be construed as a 
comprehensive list of such obligations. In many instances, the 
information simply refers to standard operating practices in existing 
industry standards and/or building codes. When using these substitutes 
in the identified end-use, EPA strongly encourages you to apply the 
information in the ``Further Information'' column. Many of these 
recommendations, if adopted, would not require significant changes to 
existing operating practices.
    It should be noted that a substitute listed as acceptable under the 
SNAP program may also be subject to requirements or limitations under 
other statutory or regulatory provisions. For example, there are 
relevant regulations under subsection (i) of the AIM Act that restrict 
the use of certain HFCs in a variety of sectors and subsectors. See 88 
FR 73098 (October 24, 2023). Consequently, if a substitute listed as 
acceptable under the SNAP program is also subject to limitations on its 
use under other regulations, it may not be permitted for use in 
accordance with those other regulations. Those intending to use a 
substitute listed as acceptable under the SNAP program may need to 
consider restrictions under subsection (i) of the AIM Act, as well as 
other relevant authorities, and must also be followed.\5\
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    \5\ For example, there may be restrictions or prohibitions in 
regulations issued under section 610 of the CAA at 40 CFR part 82 
subpart C for nonessential products containing ODS, under the Toxic 
Substances Control Act, under the Occupation Safety and Health Act, 
and under state or local laws and regulations that warrant 
consideration.
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    You can find submissions to EPA for the substitutes listed in this 
document, as well as other materials supporting the decisions in this 
action, in the docket (EPA-HQ-OAR-2003-0118) at https://www.regulations.gov.

A. Refrigeration and Air Conditioning

1. R-471A
    EPA's decision: EPA finds R-471A acceptable as a substitute for use 
in:
     Cold storage warehouses (retrofit equipment only);
     Industrial process refrigeration (retrofit equipment 
only);
     Retail food refrigeration--Refrigerated food processing 
and dispensing equipment (retrofit equipment only);
     Retail food refrigeration--Remote condensing units 
(retrofit equipment only);
     Retail food refrigeration--Supermarket systems (retrofit 
equipment only).
    R-471A, marketed under the trade name Solstice[supreg] N71, is a 
weighted blend of 78.7 percent HFO-1234ze(E), also known as trans-
1,3,3,3-tetrafluoroprop-1-ene (Chemical Abstracts Service Registry 
Number [CAS Reg. No.] 29118-24-9); 17.0 percent HFO-1336mzz(E), also 
known as trans-1,1,1,4,4,4-hexafluoro-2-butene (CAS Reg. No. 66711-86-
2); and 4.3 percent HFC-227ea, which is also known as 1,1,1,2,3,3,3-
heptafluoropropane (CAS Reg. No. 431-89-0).
    You may find a copy of the applicant's submission, with CBI 
redacted, providing the required health and environmental information 
for this substitute in this end-use in the docket (EPA-HQ-OAR-2003-
0118) at https://www.regulations.gov under the name, ``Supporting 
Materials for Notice 39 Listing of R-471A in Refrigeration and Air 
Conditioning. SNAP Submission Received September 15, 2023.'' EPA 
performed assessments to examine the health and environmental risks of 
this substitute, and the results are summarized below. These 
assessments are available in the docket EPA-HQ-OAR-2003-0118:
     ``Risk Screen on Substitutes in Retail Food Refrigeration 
(Retrofit Equipment) Substitute: R-471A (Solstice[supreg] N71).''
     ``Risk Screen on Substitutes in Industrial Process 
Refrigeration and Cold Storage Warehouses (Retrofit Equipment) 
Substitute: R-471A (Solstice[supreg] N71).''
    Environmental information: R-471A has an ozone depletion potential 
(ODP) of 0. Its components, HFO-1234ze(E), HFO-1336mzz(E), and HFC-
227ea, have GWPs of 1,\6\ 26,\7\ and 3,220,\8\ respectively. When these 
values are weighted by mass percentage of the blend, R-471A has a GWP 
of about 144. The components of R-471A are excluded from the EPA's 
regulatory definition of volatile organic compounds (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 (NAAQS). Knowingly venting or otherwise knowingly 
releasing this refrigerant blend is limited by the venting prohibition 
under section 608(c)(2) of the CAA, codified in EPA regulations at 40 
CFR 82.154(a).
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    \6\ WMO, 2022.
    \7\ WMO, 2022.
    \8\ Annex F to the Montreal Protocol.
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    Flammability information: The component HFO-1234ze(E) has lower 
flammability as defined using the standard test method American Society 
of Testing and Materials (ASTM) E681.\9\ The other two components of R-
471A are not flammable using the same

[[Page 99722]]

method. R-471A is not flammable as formulated, in the worst-case 
formulation for flammability (WCF) and the worst-case of fractionation 
for flammability (WCFF). The American Society of Heating, 
Refrigerating, and Air-Conditioning Engineers (ASHRAE) has assigned R-
471A a flammability class of ``1,'' meaning it does not propagate a 
flame under standard test conditions.\10\
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    \9\ ASTM, E681. Standard Test Method for Concentration Limits of 
Flammability of Chemicals (Vapors and Gases).
    \10\ ASHRAE Standard 34-2022: Designation and Safety 
Classification of Refrigerants. (ASHRAE, 2022).
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    Toxicity and exposure data: Potential health effects of exposure to 
this substitute include drowsiness or dizziness. The substitute may 
also irritate the skin or eyes or cause frostbite in the case of rapid 
evaporation of the liquid. The substitute could cause asphyxiation if 
air is displaced by vapors in a confined space. Excessive exposure may 
cause central nervous system effects including drowsiness and 
dizziness. Excessive exposure may also cause cardiac arrhythmia. These 
potential health effects are common to many refrigerants.
    ASHRAE has adopted an occupational exposure limit (OEL) for the 
blend of 710 ppm 11 12 on an eight-hour time-weighted 
average (8-hr TWA) for HFO-1336mzz(E), the American Industrial Hygiene 
Association (AIHA) has established a WEEL of 1,000 ppm (8-hr TWA) for 
HFC-227ea, and ASHRAE has adopted an OEL of 800 ppm (8-hr TWA) for HFO-
1234ze(E).\13\ EPA anticipates that users will be able to meet these 
workplace guidance limits and address potential health risks by 
following recommendations in the manufacturer's safety data sheet 
(SDS), ASHRAE Standard 15,\14\ other industry standards, and other 
safety precautions common to the refrigeration and air conditioning 
industry.
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    \11\ ASHRAE, 2022.
    \12\ Trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E) 
(2018). Toxicology and Industrial Health. 2019; 35(3):204-210. 
doi:10.1177/0748233719825529.
    \13\ ASHRAE, 2022.
    \14\ ASHRAE 15. Safety Standard for Refrigeration Systems.
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    Comparison to other substitutes in these end-uses: R-471A has an 
ODP of 0, comparable to or less than other listed substitutes in 
retrofits for these end-uses with ODPs ranging from 0 to less than 
0.0004.
    As a retrofit for supermarket systems, remote condensing units, and 
refrigerated food processing and dispensing equipment, R-471A with a 
GWP of 144 is lower than that of all other acceptable substitutes such 
as R-450A which has a GWP of 601; R-513A with a GWP of 630; R-448A with 
a GWP of 1,386; R-449A with a GWP of 1,396; R-449B with a GWP of 1,412; 
R-407C with a GWP of 1,770; R-407F with a GWP of 1,825; and R-407A with 
a GWP of 2,107.
    For retrofits in industrial process refrigeration, R-471A's GWP of 
144 is lower than that of other acceptable substitutes such as HFC-134a 
which has a GWP of 1,430; R-407C with a GWP of 1,770; and R-407F with a 
GWP of 1,825. Other alternatives in this sector have a lower GWP than 
R-471A such as CO2 with a GWP of 1 and R-290 (propane) with 
a GWP of 3. There may be situations in which lower-GWP options may not 
be feasible for certain retrofitted industrial process refrigeration 
equipment. For example, CO2, which has a GWP of 1 is a high-
pressure refrigerant and cannot be used as a retrofit for low-pressure 
refrigerant systems. R-471A is a low-pressure refrigerant, making it 
more technically feasible to retrofit systems that use similar low-
pressure refrigerants. R-290 is an A3, highly flammable refrigerant and 
may not be feasible for certain retrofitted industrial process 
refrigeration equipment where flammability is a concern.
    Further, refrigerants offer cooling within a specific temperature 
range. Adding R-471A to the list of available substitutes in industrial 
process refrigeration systems may offer a refrigerant that achieves a 
specific cooling temperature that other retrofit alternatives with 
lower GWPs cannot achieve.\15\ For retrofits of cold storage 
warehouses, R-471A's GWP of 144 is lower than that of all other 
acceptable substitutes such as R-450A with a GWP of 601; R-513A with a 
GWP of 630; HFC-134a with a GWP of 1,430; R-407C with a GWP of 1,770; 
and R-407F with a GWP of 1,825.
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    \15\ The October 2023 Technology Transitions Rule does not 
restrict the use of HFCs (i.e., establish GWP limits) in retrofit 
applications (See 88 FR 73127).
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    Flammability and toxicity risks are comparable to or lower than 
flammability and toxicity risks of other available substitutes in the 
same retrofit end-uses. Toxicity risks can be minimized by use 
consistent with the AIHA and OARS WEELs, ASHRAE OELs and ASHRAE 15, 
other industry standards, recommendations in the manufacturer's SDS, 
and other safety precautions common in the refrigeration and air 
conditioning industry.
    Based on the considerations described above, EPA finds R-471A 
acceptable as a retrofit refrigerant for the following end-uses: cold 
storage warehouses, industrial process refrigeration, and retail food 
refrigeration (including supermarket systems, remote condensing units, 
and refrigerated food processing and dispensing equipment), because it 
does not pose greater overall environmental and human health risk than 
other available substitutes in the same end-uses.
2. R-480A
    EPA's decision: EPA finds R-480A acceptable as a substitute for use 
in:
     Cold storage warehouses (retrofit equipment only);
     Commercial ice machines (retrofit equipment only);
     Positive displacement chillers (retrofit equipment only);
     Refrigerated transport (retrofit equipment only);
     Water coolers (retrofit equipment only).
    R-480A, marketed under the trade name RS-20, is a weighted blend of 
5 percent CO2 (CAS Reg. No. 124-38-9), 86 percent HFO-
1234ze(E), also known as trans-1,3,3,3-tetrafluoroprop-1-ene (CAS Reg. 
No. 29118-24-9), and 9 percent HFC-227ea, also known as 1,1,1,2,3,3,3-
heptafluoropropane (CAS Reg. No. 431-89-0).
    You may find a copy of the applicant's submission, with CBI 
redacted, providing the required health and environmental information 
for this substitute in this end-use in the docket (EPA-HQ-OAR-2003-
0118) at https://www.regulations.gov under the name, ``Supporting 
Materials for Notice 39 Listing of R-480A in Refrigeration and Air 
Conditioning. SNAP Submission Received May 16, 2024.'' EPA performed 
assessments to examine the health and environmental risks of this 
substitute, and the results are summarized below. These assessments are 
available in the docket EPA-HQ-OAR-2003-0118:
     ``Risk Screen on Substitutes in Cold Storage Warehouses 
(Retrofit Equipment). Substitute: R-480A (RS-20).''
     ``Risk Screen on Substitutes in Commercial Ice Machines 
(Retrofit Equipment). Substitute: R-480A (RS-20).''
     ``Risk Screen on Substitutes in Chillers (Retrofit 
Equipment). Substitute: R-480A (RS-20).''
     ``Risk Screen on Substitutes in Refrigerated Transport 
(Retrofit Equipment). Substitute: R-480A (RS-20).''
     ``Risk Screen on Substitutes in Water Coolers (Retrofit 
Equipment). Substitute: R-480A (RS-20).''
    Environmental information: R-480A has an ODP of 0. This blend 
consists of

[[Page 99723]]

CO2 with a GWP of 1,\16\ HFO-1234ze(E) with a GWP of 1,\17\ 
and HFC-227ea with a GWP of 3,220.\18\ Weighting these values by mass 
percentage results in a GWP of 291 for R-480A. The components of R-480A 
are excluded from EPA's regulatory definition of VOC under CAA 
regulations (see 40 CFR 51.100(s)) addressing the development of SIPs 
to attain and maintain the NAAQS. Knowingly venting or otherwise 
knowingly releasing this refrigerant blend is limited by the venting 
prohibition under CAA section 608(c)(2), codified at 40 CFR 82.154(a).
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    \16\ IPCC, 2007.
    \17\ WMO, 2022.
    \18\ Annex F to the Montreal Protocol.
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    Flammability information: The component HFO-1234ze(E) has lower 
flammability as defined using the standard test method ASTM E681, while 
the other two components of R-480A are not flammable using the same 
method. R-480A is not flammable as formulated, in the WCF and the WCFF. 
ASHRAE has assigned R-480A a flammability class of ``1,'' meaning it 
does not propagate a flame under standard test conditions.
    Toxicity and exposure data: The substitute may be hazardous if 
inhalation, skin contact, or eye contact with the substitute occurs at 
sufficiently high levels. The substitute could cause symptoms of 
asphyxiation if air is displaced by vapors in a confined space. These 
potential health effects are common to many refrigerants.
    ASHRAE has adopted an OEL for the blend of 900 ppm (8-hr TWA).\19\ 
For the components of R-480A, the U.S. Occupational Safety and Health 
Administration (OSHA) has established a permissible exposure limit 
(PEL) of 5,000 ppm (8-hr TWA) for CO2, AIHA has established 
a WEEL of 1,000 ppm for HFC-227ea, and ASHRAE has adopted an OEL of 800 
ppm (8-hr TWA) for HFO-1234ze(E).\20\ EPA anticipates that users will 
be able to meet these workplace guidance limits and address potential 
health risks by following recommendations in the manufacturer's SDS, 
ASHRAE Standard 15, other industry standards, and other safety 
precautions common to the refrigeration and air conditioning industry.
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    \19\ ASHRAE, 2022, Addendum h.
    \20\ ASHRAE, 2022.
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    Comparison to other substitutes in these end-uses: R-480A has an 
ODP of 0, comparable to or less than other listed substitutes in these 
end-uses with ODPs ranging from 0 to less than 0.0004.
    For cold storage warehouses, R-480A with a GWP of 291 is lower than 
all other acceptable substitutes for retrofit equipment in this end-
use, such as a number of HFC blends, including R-450A and R-513A, with 
GWPs of 601 and 630, respectively.
    For commercial ice machines, R-480A's GWP of 291 is lower than all 
other acceptable substitutes for retrofit equipment in this end-use, 
such as a number of HFC blends, including R-450A and R-513A, with GWPs 
of 601 and 630, respectively.
    For positive displacement chillers, R-480A's GWP of 291 is lower 
than that of certain other acceptable substitutes for retrofit 
equipment in this end-use, such as a number of HFC blends, including R-
450A and R-513A, with GWPs of 601 and 630, respectively. The GWP of R-
480A is higher than the GWPs of two other acceptable substitutes for 
retrofit equipment in this end-use, namely R-1224yd(Z) and R-514A, with 
GWPs of 1 \21\ and 2,\22\ respectively. EPA is listing this substitute 
as acceptable because available lower-GWP options are not feasible to 
use in certain applications. For example, equipment retrofitted with R-
480A can operate within a specific temperature range and pressure range 
that other retrofitted chillers using lower-GWP options such as R-
1224yd(Z) and R-514A cannot achieve. For refrigerated transport, R-
480A's GWP of 291 is lower than that of all other acceptable 
substitutes for retrofit equipment in this end-use, such as R-450A, R-
513A, and HFC-134a, with GWPs of 601, 630, and 1,430, respectively.
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    \21\ WMO, 2022.
    \22\ This value is calculated by weighting the GWPs of HFO-
1336mzz(Z) (2) and 1,2-dichloroethene(Z) (1) from WMO, 2022 by the 
mass percentages of the blend components of 74.7 percent and 25.3 
percent, respectively.
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    For water coolers, R-480A's GWP of 291 is lower than that of all 
other acceptable substitutes for retrofit equipment in this end-use, 
such as R-450A, R-513A, R-426A, and R-411A, with GWPs of 601, 630, 
1,510, and 1,600, respectively.
    Flammability and toxicity risks are comparable to or lower than 
flammability and toxicity risks of other available substitutes in the 
same retrofit end-uses. Toxicity risks can be minimized by use 
consistent with the OSHA PEL, AIHA WEEL, ASHRAE OELs, ASHRAE 15 and 
other industry standards, recommendations in the manufacturer's SDS, 
and other safety precautions common in the refrigeration and air 
conditioning industry.
    Based on the considerations described above, EPA finds R-480A 
acceptable in retrofit equipment in the following end-uses: cold 
storage warehouses, commercial ice machines, positive displacement 
chillers, refrigerated transport, and water coolers, because it does 
not pose greater overall environmental and human health risk than other 
available substitutes in the same end-uses.
3. R-513A
    EPA's decision: EPA finds R-513A acceptable as a substitute for use 
in:
     Residential and light commercial air conditioning and heat 
pumps--self-contained units (new equipment only).
    R-513A, marketed under the trade name Opteon[supreg] XP-10, is a 
weighted blend of 44 percent HFC-134a and 56 percent HFO-1234yf by 
weight. HFC-134a is an HFC and is also known as 1,1,1,2-
tetrafluoroethane (CAS Reg. No. 811-97-2). HFO-1234yf is an HFO and is 
also known as 2,3,3,3 tetrafluoroprop-1-ene (CAS Reg. No.754-12-1).
    You may find a copy of the applicant's submission, with CBI 
redacted, providing the required health and environmental information 
for this substitute in this end-use category in Docket EPA-HQ-OAR-2003-
0118 at www.regulations.gov under the name, ``SNAP Information Notice 
for R-513A as a Refrigerant. SNAP Submission Received January 9, 
2024.'' EPA has performed an assessment to examine the health and 
environmental risks of this substitute and the results are summarized 
below. This assessment is available in Docket EPA-HQ-OAR-2003-0118:
     ``Risk Screen on Substitutes for Use in Residential and 
Light Commercial Air Conditioning and Heat Pumps--Self-Contained Units 
(New Equipment) Substitute: R-513A (Opteon[supreg] XP-10).''
    Environmental information: R-513A is a blend of HFC-134a and HFO-
1234yf with an ODP of 0. HFC-134a has a GWP of 1,430 \23\ and HFO-
1234yf has a GWP of 1.\24\ The GWP of R-513A is 630 when the two 
components are weighted by mass percentage of their GWPs. All 
components of the blends are excluded from the EPA's regulatory 
definition of VOC under CAA regulations (see 40 CFR 51.100(s)) 
addressing the development of SIPs to attain and maintain the NAAQS. 
Knowingly venting or otherwise knowingly releasing this refrigerant 
blend is limited by the venting prohibition under section 608(c)(2) of 
the CAA, codified in EPA's regulations at 40 CFR 82.154(a).
---------------------------------------------------------------------------

    \23\ Annex F to the Montreal Protocol.
    \24\ WMO, 2022.
---------------------------------------------------------------------------

    Flammability information: The component HFO-1234yf has lower 
flammability as defined using the

[[Page 99724]]

standard test method ASTM E681. HFC-134a is not flammable using the 
same method. R-513A is not flammable as formulated in the WCF and the 
WCFF. ASHRAE has assigned R-513A a flammability class of ``1,'' meaning 
it does not propagate a flame under standard test conditions.
    Toxicity and exposure data: Potential health effects of exposure to 
this substitute include skin and eye irritation and frostbite upon 
contact. The substitute could cause asphyxiation if air is displaced by 
vapors in a confined space. These potential health effects are common 
to many refrigerants. EPA anticipates that R-513A will be used 
consistent with the recommendations specified in the SDS. ASHRAE has 
adopted an OEL for the blend R-513A of 650 ppm as an 8-hr TWA. The AIHA 
has established WEELs of 1000 ppm for HFC-134a and of 500 ppm for HFO-
1234yf, both as an 8-hr TWA. EPA anticipates that users will be able to 
meet these workplace guidance limits and will address potential health 
risks by following requirements and recommendations in the 
manufacturer's SDSs, ASHRAE Standard 15, other industry standards, and 
other safety precautions common to the refrigeration and air 
conditioning industry.
    Comparison to other refrigerants in this end-use category: R-513A 
has an ODP of 0, which is comparable to other acceptable substitutes in 
the residential and light commercial air conditioning and heat pumps--
self-contained units end-use category with ODPs ranging from 0 to less 
than 0.0004. R-513A which has a GWP of 630 is lower than or comparable 
to those of some acceptable substitutes in the same end-use category 
for which we are finding it acceptable, such as R-452B which has a GWP 
of 700 and HFC-32 which has a GWP of 675. R-513A has a GWP of 630, 
which is higher than those of other acceptable substitutes in this end-
use category such as R-290, which has a GWP of 3, R-454A, which has a 
GWP of 240, R-454B, which has a GWP of 470, R-454C, which has a GWP of 
150, and R-457A, which has a GWP of 140.
    While other acceptable substitutes have lower GWPs, EPA is listing 
R-513A as acceptable in this end-use category recognizing it likely 
will be used only in certain self-contained units that use R-134a where 
other available options are not technically feasible. Self-contained 
units can include but are not limited to window units, packaged 
terminal air conditioners, packaged terminal heat pumps, portable room 
air conditioning units, and portable air conditioners used to cool 
commercial aircraft interiors while on the ground.\25\ As a general 
matter, the replacements for most of the equipment in the residential 
and light commercial air conditioning and heat pumps end-use category 
use refrigerants that mimic the thermodynamic qualities and high 
pressure of R-410A which was the dominant refrigerant used for the 
majority of equipment types in this end-use category. There are, 
however, some specific applications where R-134a was used in self-
contained units because of its unique thermodynamic properties that 
make it a better choice. For example, self-contained portable air 
conditioners used to cool commercial aircraft while on the ground 
currently use R-134a. This refrigerant is used because R-134a is 
optimized for equipment that use screw compressors and need to be able 
to operate at extremely high ambient temperatures with high humidity. 
R-513A's thermodynamic properties closely mimic those of R-134a, making 
it an important option for applications where R-134a is used. As noted 
above, self-contained portable air conditioners used to cool the 
aircraft interior while on the ground must function in a wide range of 
ambient temperatures and humidities, making R-513A an important option 
for this specific use. Other available refrigerant options with lower 
GWPs do not have the correct thermodynamic properties to fit the 
technical needs for this specific use. In addition, R-513A and R-134a 
are both low pressure refrigerants. As a result, R-513A could replace 
R-134a in equipment with minimal modifications but it is not expected 
to replace R-410A due to the extensive re-engineering required.
---------------------------------------------------------------------------

    \25\ These are all examples of equipment defined as ``factory 
sealed appliances'' in the UL 60335-2-40 standard for electrical 
heat pumps, air-conditioners, and dehumidifiers, in which all 
refrigerating system parts have been sealed tight during the 
manufacturing process. Other equipment that meets the UL definition 
of factory sealed appliances are also self-contained units.
---------------------------------------------------------------------------

    EPA expects that use of R-513A in residential and light commercial 
air conditioning and heat pumps will be limited to a narrow set of 
specific applications because it is likely to be used only in those few 
applications where R-134a is currently used in self-contained units and 
where other available options are not technically feasible. Therefore, 
EPA is listing this refrigerant as acceptable for use in the 
residential and light commercial air conditioning and heat pumps-self-
contained units end-use category.
    Flammability and toxicity risks are comparable to or lower than 
flammability and toxicity risks of other available substitutes in the 
same end-use category. For example, R-513A is non-flammable and has 
comparable or lower flammability risk compared to other acceptable 
refrigerants in this end-use category, such as the lower flammability 
refrigerants R-454B and R-454C. Toxicity risks can be minimized by use 
consistent with the AIHA's WEELs, ASHRAE's OEL, ASHRAE 15 and other 
industry standards, recommendations in the SDS, and other safety 
precautions common in the refrigeration and air conditioning industry.
    Based on the considerations described above, EPA finds R-513A 
acceptable in new self-contained units in the residential and light 
commercial air conditioning end-use because it provides a lower-GWP 
alternative for this end-use category. R-513A does not pose greater 
overall environmental and human health risk than other available 
substitutes in the same end-use category.

B. Foam Blowing

1. Extruded Polystyrene (XPS) Blowing Agent Blends of 0 to 90 Percent 
HFO-1336mzz(Z), 0 to 90 Percent HFO-1234ze(E), 0 to 75 Percent HFC-
152a, and 0 to 90 Percent CO2
    EPA's decision: EPA finds blends of 0 to 90 percent HFO-1336mzz(Z), 
0 to 90 percent HFO-1234ze(E), 0 to 75 percent HFC-152a, and 0 to 90 
percent CO2 (``HFO-1336mzz(Z)/HFO-1234ze(E)/HFC-152a/
CO2 blends'') acceptable as a substitute for use as a foam 
blowing agent in:
     Polystyrene: extruded boardstock and billet.
    HFO-1336mzz(Z) is an HFO and is also called (Z)-1,1,1,4,4,4-
hexafluorobut-2-ene or cis-1,1,1,4,4,4-hexafluorobut-2-ene (CAS Reg. 
No. 692-49-9); it also goes by the trade names of FEA-1100 or 
Formacel[supreg] 1100. HFO-1234ze(E) is an HFO and is also known as 
trans-1,3,3,3-tetrafluoroprop-1-ene (CAS Reg. No. 29118-24-9). HFC-152a 
is an HFC and is also called ethane, 1,1-difluoro (CAS Reg. No. 75-37-
6). CO2 has CAS Reg. No. 124-38-9.
    You may find a copy of the applicant's submission, with CBI 
redacted, providing the required health and environmental information 
for this substitute in this end-use in the docket (EPA-HQ-OAR-2003-
0118) at https://www.regulations.gov under the name, ``SNAP Information 
Notice for Extruded Polystyrene Blend of 0 to 90% HFO-1336mzz(Z), 0 to 
90% HFO-1234ze(E), 0 to 75% HFC-152a, and 0 to 90% CO2 as a 
Foam Blowing Agent SNAP Submission Received August 7, 2023.''

[[Page 99725]]

EPA has performed an assessment to examine the health and environmental 
risks of this substitute. This assessment is available in the docket 
EPA-HQ-OAR-2003-0118:
     ``Risk Screen on Substitutes for Use in Extruded 
Polystyrene Boardstock and Billet Foam Substitute: HFO-1336mzz(Z)/HFO-
1234ze(E)/HFC-152a/CO2 Blends.''
    Environmental information: These HFO-1336mzz(Z)/HFO-1234ze(E)/HFC-
152a/CO2 foam blowing agent blends have an ODP of 0. The 
components, HFO-1336mzz(Z), HFO-1234ze(E), HFC-152a, and CO2 
have GWPs of 2,\26\ 1,\27\ 124,\28\ and 1, respectively. The GWPs of 
the blowing agent blends using these components range from 1 to 94. 
These reflect the composition ranges that result in the lowest GWP of 1 
to the highest GWP of 94 given the GWP and range of percentages for 
each component. The components of the HFO-1336mzz(Z)/HFO-1234ze(E)/HFC-
152a/CO2 blends are excluded from EPA's regulatory 
definition of VOC under CAA regulations (see 40 CFR 51.100(s)) 
addressing the development of SIPs to attain and maintain the NAAQS.
---------------------------------------------------------------------------

    \26\ WMO, 2022.
    \27\ WMO, 2022.
    \28\ Annex F to the Montreal Protocol.
---------------------------------------------------------------------------

    Flammability information: The component HFC-152a is flammable at 
standard temperature and pressure as defined by standard test method 
ASTM E681. HFO-1336mzz(Z) and HFO-1234ze(E) are not flammable at 
standard temperature and pressure using the same method. However, at 
higher temperatures, such as the temperatures typical for extruding 
XPS, HFO-1234ze(E) may also be flammable, particularly at higher 
humidity levels.\29\ HFO-1336mzz(Z)/HFO-1234ze(E)/HFC-152a/
CO2 blends anticipated to be used in manufacturing 
polystyrene: extruded boardstock and billet are flammable at the 
temperatures typical for extruding XPS.
---------------------------------------------------------------------------

    \29\ Bellair and Hood, 2019. Comprehensive evaluation of the 
flammability and ignitability of HFO-1234ze, R.J. Bellair and L. 
Hood, Process Safety and Environmental Protection 132 (2019) 273-
284. Available online at doi.org/10.1016/j.psep.2019.09.033.
---------------------------------------------------------------------------

    Toxicity and exposure data: Potential health effects of exposure to 
this substitute include skin or eye irritation or frostbite. At 
sufficiently high concentrations, the substitute may cause irregular 
heartbeat. The substitute could cause asphyxiation if air is displaced 
by vapors in a confined space. These potential health effects are 
common to many foam blowing agents. Exposure may be possible during the 
blowing of the foam if the foam manufacturer does not take standard 
precautions such as the use of personal protective equipment. EPA 
anticipates that these HFO-1336mzz(Z)/HFO-1234ze(E)/HFC-152a/
CO2 blends will be used consistent with the recommendations 
specified in the SDS.
    The AIHA has established a WEEL of 1,000 ppm for HFC-152a as an 8-
hr TWA. The WEEL committee of the OARS has established a WEEL of 500 
ppm \30\ for HFO-1336mzz(Z). OSHA has established a PEL of 5,000 ppm on 
an 8-hr TWA for CO2. The manufacturer of HFO-1234ze(E) 
recommends an OEL of 800 ppm \31\ (8-hr TWA) for this chemical. EPA 
anticipates that users will be able to meet the AIHA and OARS WEELs, 
OSHA PEL, and manufacturer's OEL and will follow requirements and 
recommendations in the manufacturer's SDSs and other safety precautions 
common to the foam blowing industry, thereby addressing potential 
health risks.
---------------------------------------------------------------------------

    \30\ Cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z) (2018). 
Toxicology and Industrial Health. 2019;35(3):180-188. doi:10.1177/
0748233719825530.
    \31\ ASHRAE, 2022.
---------------------------------------------------------------------------

    Comparison to other foam blowing agents in this end-use: These HFO-
1336mzz(Z)/HFO-1234ze(E)/HFC-152a/CO2 blends have an ODP of 
0, comparable to other acceptable substitutes in the polystyrene: 
extruded boardstock and billet end-use, such as HFC-152a, HFO-
1234ze(E), methyl formate, and CO2. These HFO-1336mzz(Z)/
HFO-1234ze(E)/HFC-152a/CO2 blends' GWPs from 1 to 94 are 
lower than or comparable to those of other acceptable substitutes in 
the same end-use for which we are finding it acceptable. Examples 
include HFC-152a, HFO-1234ze(E), light saturated hydrocarbons C3-C6, 
and methyl formate, with respective GWPs of 124,\32\ 1,\33\ less than 
4,\34\ and 11.\35\ Depending on the specific composition, the blend 
used may have a higher GWP than that of some individual chemicals that 
are acceptable substitutes in this end-use that are more flammable 
(e.g., HFO-1234ze(E)) or are less able to meet standard specifications 
(e.g., ASTM C578) than the blends because of properties such as 
solvency in the plastic resin (e.g., HFO-1336mzz(Z)) or contributions 
to insulation value (e.g., CO2, water).
---------------------------------------------------------------------------

    \32\ Annex F to the Montreal Protocol.
    \33\ WMO, 2022.
    \34\ IPCC, 2007.
    \35\ WMO, 2022.
---------------------------------------------------------------------------

    Flammability and toxicity risks are comparable to or lower than 
flammability and toxicity risks of other available substitutes in the 
same end-use. Toxicity risks can be minimized by use consistent with 
the AIHA's and OARS's WEELs, OSHA's PEL, recommendations in the SDS, 
and other safety precautions common in the foam blowing industry.
    Based on the considerations described above, EPA finds blends of 0 
to 90 percent HFO-1336mzz(Z), 0 to 90 percent HFO-1234ze(E), 0 to 75 
percent HFC-152a, and 0 to 90 percent CO2 acceptable in the 
polystyrene: extruded boardstock and billet end-use because they do not 
pose greater overall environmental and human health risk than other 
available substitutes in the same end-use.

List of Subjects in 40 CFR Part 82

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Reporting and recordkeeping requirements.

Paul M. Gunning,
Director, Office of Atmospheric Protection.

Appendix A: Summary of Decisions for New Acceptable Substitutes

                                       Refrigeration and Air Conditioning
----------------------------------------------------------------------------------------------------------------
             End-use                     Substitute                Decision            Further information \1\
----------------------------------------------------------------------------------------------------------------
Cold storage warehouses           R-471A.................  Acceptable.............  This substitute is a blend
 (retrofit equipment only).                                                          of 78.7 percent
                                                                                     hydrofluoroolefin (HFO)-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene;
                                                                                     (Chemical Abstracts Service
                                                                                     Registry Number [CAS Reg.
                                                                                     No.] 29118-24-9); 17.0
                                                                                     percent HFO-1336mzz(E),
                                                                                     also known as trans-
                                                                                     1,1,1,4,4,4-hexafluoro-2-
                                                                                     butene (CAS Reg. No. 66711-
                                                                                     86-2); and 4.3 percent HFC-
                                                                                     227ea, which is also known
                                                                                     as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-471A has a global warming
                                                                                     potential (GWP) of 144 and
                                                                                     an ozone depletion
                                                                                     potential (ODP) of 0. The
                                                                                     blend is not flammable as
                                                                                     it has an American Society
                                                                                     of Heating, Refrigerating,
                                                                                     and Air-Conditioning
                                                                                     Engineers (ASHRAE)
                                                                                     flammability classification
                                                                                     of ``1''.

[[Page 99726]]

 
                                                                                    ASHRAE has adopted an
                                                                                     occupational exposure limit
                                                                                     (OEL) for the blend of 710
                                                                                     ppm on an eight-hour time-
                                                                                     weighted average (8-hr
                                                                                     TWA). For the components of
                                                                                     R-471A, the Workplace
                                                                                     Environmental Exposure
                                                                                     Limit (WEEL) Committee of
                                                                                     the Occupational Alliance
                                                                                     for Risk Science (OARS) has
                                                                                     established a WEEL of 400
                                                                                     ppm on an 8-hr TWA for HFO-
                                                                                     1336mzz(E), the AIHA has
                                                                                     established a WEEL of 1,000
                                                                                     ppm for HFC-227ea (8-hr
                                                                                     TWA), and ASHRAE has
                                                                                     adopted an OEL of 800 ppm
                                                                                     on an 8-hr TWA for HFO-
                                                                                     1234ze(E).
Cold storage warehouses           R-480A.................  Acceptable.............  This substitute is a
 (retrofit equipment only).                                                          weighted blend of 5 percent
                                                                                     CO2, 86 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene CAS
                                                                                     Reg. No. 29118-24-9), and 9
                                                                                     percent HFC-227ea, which is
                                                                                     also known as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-480A has a GWP of 291 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1.''
                                                                                    ASHRAE has adopted an OEL
                                                                                     for the blend of 900 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-480A, the Occupational
                                                                                     Safety and Health
                                                                                     Administration (OSHA) has
                                                                                     established a permissible
                                                                                     exposure limit (PEL) for
                                                                                     CO2 of 5,000 ppm on an 8-hr
                                                                                     TWA, AIHA has established a
                                                                                     WEEL of 1,000 ppm for HFC-
                                                                                     227ea (8-hr TWA), and
                                                                                     ASHRAE has adopted an OEL
                                                                                     of 800 ppm on an 8-hr TWA
                                                                                     for HFO-1234ze(E).
Commercial ice machines           R-480A.................  Acceptable.............  This substitute is a
 (retrofit equipment only).                                                          weighted blend of 5 percent
                                                                                     CO2, 86 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene CAS
                                                                                     Reg. No. 29118-24-9), and 9
                                                                                     percent HFC-227ea, which is
                                                                                     also known as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-480A has a GWP of 291 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1.''
                                                                                    ASHRAE has adopted an OEL
                                                                                     for the blend of 900 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-480A, OSHA has
                                                                                     established a PEL for CO2
                                                                                     of 5,000 ppm on an 8-hr
                                                                                     TWA, AIHA has established a
                                                                                     WEEL of 1,000 ppm for HFC-
                                                                                     227ea (8-hr TWA), and
                                                                                     ASHRAE has adopted an OEL
                                                                                     of 800 ppm on an 8-hr TWA
                                                                                     for HFO-1234ze(E).
Industrial process refrigeration  R-471A.................  Acceptable.............  This substitute is a blend
 (retrofit equipment only).                                                          of 78.7 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene; (CAS
                                                                                     Reg. No. 29118-24-9); 17.0
                                                                                     percent HFO-1336mzz(E),
                                                                                     also known as trans-
                                                                                     1,1,1,4,4,4-hexafluoro-2-
                                                                                     butene (CAS Reg. No. 66711-
                                                                                     86-2); and 4.3 percent HFC-
                                                                                     227ea, which is also known
                                                                                     as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-471A has a GWP of 144 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1''.
                                                                                    ASHRAE has adopted an OEL
                                                                                     for the blend of 710 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-471A, OARS has
                                                                                     established a WEEL of 400
                                                                                     ppm on an 8-hr TWA for HFO-
                                                                                     1336mzz(E), AIHA has
                                                                                     established a WEEL of 1,000
                                                                                     ppm for HFC-227ea (8-hr
                                                                                     TWA), and ASHRAE has
                                                                                     adopted an OEL of 800 ppm
                                                                                     on an 8-hr TWA for HFO-
                                                                                     1234ze(E).
Positive displacement chillers    R-480A.................  Acceptable.............  This substitute is a
 (retrofit equipment only).                                                          weighted blend of 5 percent
                                                                                     CO2, 86 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene CAS
                                                                                     Reg. No. 29118-24-9), and 9
                                                                                     percent HFC-227ea, which is
                                                                                     also known as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-480A has a GWP of 291 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1.''
                                                                                     ASHRAE has adopted an OEL
                                                                                     for the blend of 900 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-480A, the Occupational
                                                                                     Safety and Health
                                                                                     Administration (OSHA) has
                                                                                     established a permissible
                                                                                     exposure limit (PEL) for
                                                                                     CO2 of 5,000 ppm on an 8-hr
                                                                                     TWA, AIHA has established a
                                                                                     WEEL of 1,000 ppm for HFC-
                                                                                     227ea (8-hr TWA), and
                                                                                     ASHRAE has adopted an OEL
                                                                                     of 800 ppm on an 8-hr TWA
                                                                                     for HFO-1234ze(E).
Refrigerated transport (retrofit  R-480A.................  Acceptable.............  This substitute is a
 equipment only).                                                                    weighted blend of 5 percent
                                                                                     CO2, 86 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene CAS
                                                                                     Reg. No. 29118-24-9), and 9
                                                                                     percent HFC-227ea, which is
                                                                                     also known as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-480A has a GWP of 291 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1.''
                                                                                     ASHRAE has adopted an OEL
                                                                                     for the blend of 900 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-480A, OSHA has
                                                                                     established a PEL for CO2
                                                                                     of 5,000 ppm on an 8-hr
                                                                                     TWA, AIHA has established a
                                                                                     WEEL of 1,000 ppm for HFC-
                                                                                     227ea (8-hr TWA), and
                                                                                     ASHRAE has adopted an OEL
                                                                                     of 800 ppm on an 8-hr TWA
                                                                                     for HFO-1234ze(E).
Residential and light commercial  R-513A.................  Acceptable.............  This HFC-134a/HFO-1234yf
 air conditioning and heat                                                           blend R-513A has an ODP of
 pumps--self-contained units                                                         0. Its components include
 (new equipment only).                                                               HFC-134a which has a GWP of
                                                                                     1,430 and HFO-1234yf which
                                                                                     has a GWP of 1. If these
                                                                                     values are weighted by mass
                                                                                     percentage, then the blend
                                                                                     would have a GWP of 630.
                                                                                     All components of the
                                                                                     blends are excluded from
                                                                                     EPA's regulatory definition
                                                                                     of VOC under CAA
                                                                                     regulations (see 40 CFR
                                                                                     51.100(s)).
                                                                                    ASHRAE has assigned R-513A a
                                                                                     flammability class of
                                                                                     ``1,'' meaning it does not
                                                                                     propagate a flame under
                                                                                     standard test conditions.
                                                                                     ASHRAE has adopted an OEL
                                                                                     for the blend R-513A of 650
                                                                                     ppm (8-hr TWA). The AIHA
                                                                                     has established WEELs of
                                                                                     1000 ppm for HFC-134a and
                                                                                     of 500 ppm for HFO-1234yf,
                                                                                     both as an 8-hr TWA.
Retail food refrigeration--       R-471A.................  Acceptable.............  This substitute is a blend
 Refrigerated food processing                                                        of 78.7 percent HFO-
 and dispensing equipment                                                            1234ze(E), which is also
 (retrofit equipment only).                                                          known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene; (CAS
                                                                                     Reg. No. 29118-24-9); 17.0
                                                                                     percent HFO-1336mzz(E),
                                                                                     also known as trans-
                                                                                     1,1,1,4,4,4-hexafluoro-2-
                                                                                     butene (CAS Reg. No. 66711-
                                                                                     86-2); and 4.3 percent HFC-
                                                                                     227ea, which is also known
                                                                                     as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-471A has a GWP of 144 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1''.
                                                                                     ASHRAE has established an
                                                                                     OEL for the blend of 710
                                                                                     ppm on an eight-hour time-
                                                                                     weighted average (8-hr
                                                                                     TWA). For the components of
                                                                                     R-471A, OARS has
                                                                                     established a WEEL of 400
                                                                                     ppm on an 8-hr TWA for HFO-
                                                                                     1336mzz(E), AIHA has
                                                                                     established a WEEL of 1,000
                                                                                     ppm for HFC-227ea (8-hr
                                                                                     TWA), and ASHRAE has
                                                                                     adopted an OEL of 800 ppm
                                                                                     on an 8-hr TWA for HFO-
                                                                                     1234ze(E).

[[Page 99727]]

 
Retail food refrigeration--       R-471A.................  Acceptable.............  This substitute is a blend
 Remote condensing units                                                             of 78.7 percent HFO-
 (retrofit equipment only).                                                          1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene; (CAS
                                                                                     Reg. No. 29118-24-9); 17.0
                                                                                     percent HFO-1336mzz(E),
                                                                                     also known as trans-
                                                                                     1,1,1,4,4,4-hexafluoro-2-
                                                                                     butene (CAS Reg. No. 66711-
                                                                                     86-2); and 4.3 percent HFC-
                                                                                     227ea, which is also known
                                                                                     as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-471A has a GWP of 144 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1''.
                                                                                     ASHRAE has established an
                                                                                     OEL for the blend of 710
                                                                                     ppm (8-hr TWA). For the
                                                                                     components of R-471A, OARS
                                                                                     has established a WEEL of
                                                                                     400 ppm on an 8-hr TWA for
                                                                                     HFO-1336mzz(E), AIHA has
                                                                                     established a WEEL of 1,000
                                                                                     ppm for HFC-227ea (8-hr
                                                                                     TWA), and ASHRAE has
                                                                                     adopted an OEL of 800 ppm
                                                                                     on an 8-hr TWA for HFO-
                                                                                     1234ze(E).
Retail food refrigeration--       R-471A.................  Acceptable.............  This substitute is a blend
 Supermarket systems (retrofit                                                       of 78.7 percent HFO-
 equipment only).                                                                    1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene; (CAS
                                                                                     Reg. No. 29118-24-9); 17.0
                                                                                     percent HFO-1336mzz(E),
                                                                                     also known as trans-
                                                                                     1,1,1,4,4,4-hexafluoro-2-
                                                                                     butene (CAS Reg. No. 66711-
                                                                                     86-2); and 4.3 percent HFC-
                                                                                     227ea, which is also known
                                                                                     as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-471A has a GWP of 144 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1''.
                                                                                     ASHRAE has established an
                                                                                     OEL for the blend of 710
                                                                                     ppm (8-hr TWA). For the
                                                                                     components of R-471A, OARS
                                                                                     has established a WEEL of
                                                                                     400 ppm on an 8-hr TWA for
                                                                                     HFO-1336mzz(E), AIHA has
                                                                                     established a WEEL of 1,000
                                                                                     ppm for HFC-227ea (8-hr
                                                                                     TWA), and ASHRAE has
                                                                                     adopted an OEL of 800 ppm
                                                                                     on an 8-hr TWA for HFO-
                                                                                     1234ze(E).
Water coolers (retrofit           R-480A.................  Acceptable.............  This substitute is a
 equipment only).                                                                    weighted blend of 5 percent
                                                                                     CO2, 86 percent HFO-
                                                                                     1234ze(E), which is also
                                                                                     known as trans-1,3,3,3-
                                                                                     tetrafluoroprop-1-ene CAS
                                                                                     Reg. No. 29118-24-9), and 9
                                                                                     percent HFC-227ea, which is
                                                                                     also known as 1,1,1,2,3,3,3-
                                                                                     heptafluoropropane (CAS
                                                                                     Reg. No. 431-89-0).
                                                                                    R-480A has a GWP of 291 and
                                                                                     an ODP of 0. The blend is
                                                                                     not flammable as it has an
                                                                                     ASHRAE flammability
                                                                                     classification of ``1.''
                                                                                     ASHRAE has adopted an OEL
                                                                                     for the blend of 900 ppm (8-
                                                                                     hr TWA). For the components
                                                                                     of R-480A, OSHA has
                                                                                     established a PEL for CO2
                                                                                     of 5,000 ppm on an 8-hr
                                                                                     TWA, AIHA has established a
                                                                                     WEEL of 1,000 ppm for HFC-
                                                                                     227ea (8-hr TWA), and
                                                                                     ASHRAE has adopted an OEL
                                                                                     of 800 ppm on an 8-hr TWA
                                                                                     for HFO-1234ze(E).
----------------------------------------------------------------------------------------------------------------
\1\ See recommendations in the manufacturer's SDS and guidance for all listed refrigerants.

                                                  Foam Blowing
----------------------------------------------------------------------------------------------------------------
             End-use                    Substitute               Decision             Further information \1\
----------------------------------------------------------------------------------------------------------------
Polystyrene: Extruded boardstock   Extruded polystyrene  Acceptable..............  HFO-1234ze(E) is also known
 and billet.                        (XPS) foam blowing                              as trans-1,3,3,3-
                                    agent blends of 0                               tetrafluoroprop-1-ene
                                    to 90 percent HFO-                              (Chemical Abstracts Service
                                    1336mzz(Z), 0 to 90                             Registry Number [CAS Reg.
                                    percent HFO-                                    No.] 29118-24-9). HFO-
                                    1234ze(E), 0 to 75                              1336mzz(Z) is also known as
                                    percent HFC-152a,                               (Z)-1,1,1,4,4,4-hexafluoro-2-
                                    and 0 to 90 percent                             butene and cis-1,1,1,4,4,4-
                                    CO2.                                            hexafluoro-2-butene (CAS
                                                                                    Reg. No. 692-49-9). HFC-152a
                                                                                    is also known as 1,1-
                                                                                    difluoroethane (CAS Reg. No.
                                                                                    75-37-6). CO2 has CAS Reg.
                                                                                    No. 124-38-9.
                                                                                   These blends have 100-year
                                                                                    GWPs from 1 to about 94,
                                                                                    depending on the specific
                                                                                    composition. Blends of these
                                                                                    compounds anticipated to be
                                                                                    used in manufacturing are
                                                                                    flammable.
                                                                                   The AIHA has established a
                                                                                    WEEL of 1,000 ppm for HFC-
                                                                                    152a on an eight-hour Time-
                                                                                    Weighted Average (8-hr TWA).
                                                                                    The OARS has established a
                                                                                    WEEL of 500 ppm (8-hr TWA)
                                                                                    for HFO-1336mzz(Z). The
                                                                                    manufacturer of HFO-
                                                                                    1234ze(E) has established an
                                                                                    OEL of 800 ppm (8-hr TWA)
                                                                                    and the American Society of
                                                                                    Heating, Refrigerating and
                                                                                    Air-Conditioning Engineers
                                                                                    has adopted an OEL of 800
                                                                                    ppm (8-hr TWA) for this
                                                                                    compound. The U.S. OSHA has
                                                                                    established a PEL of 5,000
                                                                                    ppm on an 8-hr TWA for CO2.
----------------------------------------------------------------------------------------------------------------
\1\ See recommendations in the manufacturer's SDS and guidance for all listed foam blowing agents.

[FR Doc. 2024-28307 Filed 12-10-24; 8:45 am]
BILLING CODE 6560-50-P
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