[Federal Register Volume 87, Number 144 (Thursday, July 28, 2022)]
[Proposed Rules]
[Pages 45508-45562]
[FR Doc No: 2022-14665]

Vol. 87

Thursday,

No. 144

July 28, 2022

Part III

Environmental Protection Agency

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40 CFR Part 82

Protection of Stratospheric Ozone: Listing of Substitutes Under the
Significant New Alternatives Policy Program in Refrigeration, Air
Conditioning, and Fire Suppression; Proposed Rule

Federal Register / Vol. 87, No. 144 / Thursday, July 28, 2022 /
Proposed Rules

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 82

[EPA-HQ-OAR-2021-0836; FRL-6399-01-OAR]
RIN 2060-AT78

Protection of Stratospheric Ozone: Listing of Substitutes Under
the Significant New Alternatives Policy Program in Refrigeration, Air
Conditioning, and Fire Suppression

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: Pursuant to the U.S. Environmental Protection Agency's
Significant New Alternatives Policy program, this action proposes to
list certain substances as acceptable subject to use conditions in the
refrigeration and air conditioning sector for chillers--comfort
cooling, residential dehumidifiers, non-residential dehumidifiers,
residential and light commercial air conditioning and heat pumps, and a
substance as acceptable subject to use conditions and narrowed used
limits in very low temperature refrigeration. Through this action, EPA
is proposing to incorporate by reference standards which establish
requirements for electrical air conditioners, heat pumps, and
dehumidifiers, laboratory equipment containing refrigerant, safe use of
flammable refrigerants, and safe design, construction, installation,
and operation of refrigeration systems. Additionally, this action
proposes to list certain substances as acceptable subject to use
conditions in the fire suppression sector for certain streaming and
total flooding uses. Finally, EPA requests advance comment on potential
approaches to SNAP listing decisions for very short-lived substances
that have ozone depletion potentials similar to those of ozone-
depleting substances scheduled to be phased out.

DATES: Comments must be received on or before September 12, 2022. 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 August 2, 2022. If a virtual public hearing is held, it will take
place on or before August 12, 2022 and further information will be
provided on EPA's Stratospheric Ozone website at https://www.epa.gov/snap.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2021-0836. All documents in the docket are listed on the
https://www.regulations.gov website. 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. 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
electronically through https://www.regulations.gov or in hard copy at
the Air and Radiation Docket, EPA/DC, EPA West, Room 3334, 1301
Constitution Avenue NW, Washington, DC 20460. 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 EPA Docket Center services and
the current status, please visit https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Holly Tapani, Stratospheric Protection
Division, Office of Atmospheric Programs (Mail Code 6205T),
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington,
DC 20460; telephone number:<PHONE_NUMBER>; email address:
[email protected]. Notices and rulemakings under EPA's Significant
New Alternatives Policy program are available on EPA's SNAP website at
https://www.epa.gov/snap/snap-regulations.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
    A. Executive Summary and Background
    B. Does this action apply to me?
    C. What acronyms and abbreviations are used in the preamble?
II. What is EPA proposing in this action?
    A. Chillers--Proposed Listing of HFO-1234yf, R-454A, R-454B, and
R-454C as Acceptable, Subject to Use Conditions, for Use in New
Chiller Equipment, and Proposed Listing of HFC-32 and R-452B as
Acceptable, Subject to Use Conditions, for Use in New Rotary and
Scroll Chiller Equipment, for Chillers Used in Comfort Cooling,
Including Both Commercial and Industrial Process AC
    1. Background on Chillers--Commercial AC and Industrial Process
AC
    2. What are the American Society of Heating, Refrigerating and
Air-Conditioning Engineers (ASHRAE) classifications for refrigerant
flammability?
    3. What are HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-
454C and how do they compare to other refrigerants in the same end-
use?
    4. Why is EPA proposing these specific use conditions?
    5. What additional information is EPA including in these
proposed listings?
    6. On which topics is EPA specifically requesting comment?
    B. Residential Dehumidifiers--Proposed Listing of HFO-1234yf,
HFC-32, R-452B, R-454A, R-454B, and R-454C as Acceptable, Subject to
Use Conditions, for Use in New Residential Dehumidifiers End-Use
    1. Background on Residential Dehumidifiers
    2. What are the ASHRAE classifications for refrigerant
flammability?
    3. What are HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-
454C and how do they compare to other refrigerants in the same end-
use?
    4. Why is EPA proposing these specific use conditions?
    5. What additional information is EPA including in these
proposed listings?
    6. On which topics is EPA specifically requesting comment?
    C. Non-Residential Dehumidifiers--Proposed Listing HFC-32 as
Acceptable, Subject to Use Conditions, for Use in New Non-
Residential Dehumidifiers End-Use
    1. Background on Non-Residential Dehumidifiers
    2. What are the ASHRAE classifications for refrigerant
flammability?
    3. What is HFC-32 and how does it compare to other refrigerants
in the same end-use?
    4. Why is EPA proposing these specific use conditions?
    5. What additional information is EPA including in these
proposed listings?
    6. On which topics is EPA specifically requesting comment?
    D. Residential and Light Commercial AC and Heat Pumps (HPs)--
Proposed Listing of HFC-32 as Acceptable, Subject to Use Conditions,
for Use in New Self-Contained Room ACs and HPs End-Use
    1. Background on Self-Contained Room ACs and HPs
    2. What are the ASHRAE classifications for refrigerant
flammability?
    3. What is HFC-32 and how does it compare to other refrigerants
in the same end-use?
    4. What use conditions currently apply to this refrigerant in
this end-use category?
    5. What use conditions is EPA proposing?
    6. How do the proposed use conditions differ from the existing
ones and why is EPA proposing to change the use conditions?
    7. What is the acceptability status of HFC-32 in self-contained
room ACs and HPs?
    8. What additional information is EPA including in these
proposed listings?
    9. On which topics is EPA specifically requesting comment?
    E. Use Conditions and Further Information for Chillers,
Residential Dehumidifiers, Non-Residential Dehumidifiers, and HFC-32
Self-Contained Room ACs and HPs
    1. What use conditions is EPA proposing and why?
    2. What additional information is EPA including in these
proposed listings?
    3. On which topics is EPA specifically requesting comment?
    F. Very Low Temperature Refrigeration (VLTR)--Proposed Listing
of R-1150 as

Acceptable, Subject to Use Conditions and Narrowed Use Limits, for
Use in VLTR End-Use
    1. Background on VLTR
    2. What is EPA's proposed listing decision for R-1150?
    3. What is R-1150 and how does it compare to other refrigerants
in the same end-use?
    4. What use conditions is EPA proposing?
    5. Why is EPA proposing these specific use conditions?
    6. What narrowed use limits is EPA proposing?
    7. Why is EPA proposing these specific narrowed use limits?
    8. What additional information is EPA including in these
proposed listings?
    9. On which topics is EPA specifically requesting comment?
    G. Streaming and Total Flooding Fire Suppression--Proposed
Listing of 2-bromo-3,3,3-trifluoropropene (2-BTP) as Acceptable,
Subject to Use Conditions, as a Streaming Agent in Non-Residential
Applications and as a Total Flooding Agent in Normally Unoccupied
Spaces Under 500 ft\3\
    1. Background on Streaming and Total Flooding Fire Suppression
    2. What is EPA's proposed listing decision for 2-BTP?
    3. What is 2-BTP and how does it compare to other fire
suppressants in the same end-uses?
    4. What use conditions is EPA proposing?
    5. Why is EPA proposing these specific use conditions?
    6. On which topics is EPA specifically requesting comment?
    H. Total Flooding Fire Suppression--Proposed Listing of
EXXFIRE[supreg] as Acceptable, Subject to Use Conditions, for Use in
Normally Unoccupied Spaces
    1. What is EPA's proposed listing decision for EXXFIRE[supreg]?
    2. What is EXXFIRE[supreg] and how does it compare to other fire
suppressants in the same end-use?
    3. What use conditions is EPA proposing and why?
    4. On which topics is EPA specifically requesting comment?
    I. Total Flooding Fire Suppression--Proposed Listing of Powdered
Aerosol H (Pyroquench-[alpha]TM) as Acceptable, Subject
to Use Conditions, for Use in Normally Unoccupied Spaces
    1. What is EPA's proposed listing decision for Powdered Aerosol
H?
    2. What is Powdered Aerosol H and how does it compare to other
fire suppressants in the same end-use?
    3. What use conditions is EPA proposing and why?
    4. On which topics is EPA specifically requesting comment?
III. Request for Advance Comment on Potential Approaches to SNAP
Listing Decisions for Certain Very Short-Lived Substances
IV. 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 (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    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
V. References

I. General Information

A. Executive Summary and Background

    This action proposes to list new alternatives for the refrigeration
and air conditioning (AC) and fire suppression sectors. Specifically,
EPA is:
     Listing hydrofluoroolefin (HFO)-1234yf, R-454A, R-454B,
and R-454C as acceptable, subject to use conditions, for use in
chillers used in comfort cooling, including commercial and industrial
process AC;
     Listing hydrofluorocarbon (HFC)-32 and R-452B as
acceptable, subject to use conditions, for use in scroll and rotary
chillers used in comfort cooling, including commercial and industrial
process AC;
     Listing HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-
454C as acceptable, subject to use conditions, for use in residential
dehumidifiers;
     Listing HFC-32 as acceptable, subject to use conditions,
for use in non-residential dehumidifiers;
     Listing HFC-32 as acceptable, subject to use conditions,
for use in self-contained room air conditioners (ACs) and heat pumps
(HPs);
     Listing R-1150 as acceptable, subject to use conditions
and narrowed use limits, for use in very low temperature refrigeration
(VLTR);
     Listing 2-bromo-3,3,3-trifluoropropene (2-BTP) as
acceptable, subject to use conditions, in streaming--for non-
residential use, except home offices and boats--and total flooding--in
normally unoccupied spaces under 500 ft\3\;
     Listing of EXXFIRE[supreg] as acceptable, subject to use
conditions, in total flooding--for normally unoccupied areas; and
     Listing of Powdered Aerosol H, also known as Pyroquench-
[alpha]TM, as acceptable, subject to use conditions, in
total flooding--for normally unoccupied areas.
    EPA is proposing these new listings after its evaluation of human
health and environmental information for these substitutes under the
Significant New Alternatives Policy (SNAP) program. The Agency is
proposing action on these new listings in the refrigeration and AC
sector and the fire suppression sector based on the information that
EPA has included in the docket. This proposed action provides
additional flexibility for industry by providing new options in
specific uses.
    Additionally, EPA requests advance comment on potential approaches
to SNAP listing decisions for very short-lived substances (VSLS) that
have ozone depletion potentials (ODPs) similar to those of class II
ozone-depleting substances (ODS) that are currently being phased out,
in particular trifluoroiodomethane (CF3I) and blends
containing CF3I. EPA is not proposing to include any
regulatory requirements with respect to such VSLS in this rulemaking.
    EPA is not requesting comment on the republication of the first six
entries of the table titled ``Substitutes That Are Acceptable Subject
to Use Conditions''. Those entries are being republished to bring the
table in line with the Office of the Federal Register's general
requirement for orderly codification by: adding entry numbers,
replacing prohibited language, and properly formatting the footnotes.

SNAP Program Background

    The SNAP program implements section 612 of the Clean Air Act (CAA).
Several major provisions of section 612 are:
1. Rulemaking
    Section 612(c) requires EPA to promulgate rules making it unlawful
to replace any class I (chlorofluorocarbon (CFC), halon, carbon
tetrachloride, methyl chloroform, methyl bromide,
hydrobromofluorocarbon, and chlorobromomethane) or class II
(hydrochlorofluorocarbon (HCFC)) ODS 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
that it finds to be unacceptable for specific uses and to publish a
corresponding list

of acceptable substitutes for specific uses.
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).
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 a new or existing chemical is introduced into
interstate commerce for significant new use as a substitute for a class
I substance. The producer must also provide the Agency with the
producer's unpublished health and safety studies on such substitutes.
    The regulations for the SNAP program are promulgated at 40 Code of
Federal Regulations (CFR) part 82, subpart G, and the Agency's process
for reviewing SNAP submissions is described in regulations at 40 CFR
82.180. Under these rules, the Agency has identified five types of
listing decisions: acceptable; acceptable subject to use conditions;
acceptable subject to narrowed use limits; unacceptable; and pending
(40 CFR 82.180(b)). Use conditions and narrowed use limits are both
considered ``use restrictions,'' as described below. Substitutes that
are deemed acceptable with no use restrictions (no use conditions or
narrowed use limits) can be used for all applications within the
relevant end-uses in the sector. After reviewing a substitute, the
Agency may determine that a substitute is acceptable only if certain
conditions in the way that the substitute is used are met to minimize
risks to human health and the environment. EPA describes such
substitutes as ``acceptable subject to use conditions'' (40 CFR
82.180(b)(2)). 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.'' Under the narrowed
use limit, users intending to adopt these substitutes ``must ascertain
that other alternatives are not technically feasible.'' (40 CFR
82.180(b)(3)).
    In making decisions regarding whether a substitute is acceptable or
unacceptable, and whether substitutes present risks that are lower than
or comparable to risks from other substitutes that are currently or
potentially available in the end-uses under consideration, EPA examines
the criteria in 40 CFR 82.180(a)(7): (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.
    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 under SNAP, 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 U.S. Occupational Safety and Health Administration
(OSHA)). The ``further information'' classification 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.
    For additional information on the SNAP program, visit the SNAP
website at https://www.epa.gov/snap. The full lists of acceptable
substitutes for ODS in all industrial sectors are available at https://www.epa.gov/snap/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
published March 18, 1994 (59 FR 13044), codified at 40 CFR part 82,
subpart G. SNAP decisions and the appropriate Federal Register
citations can be found at: https://www.epa.gov/snap/snap-regulations.
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.

B. Does this action apply to me?

    The following list identifies regulated entities that may be
affected by this rule and their respective North American Industrial
Classification System (NAICS) codes:

 Plumbing, Heating, and Air Conditioning Contractors (NAICS
238220)
 All Other Basic Organic Chemical Manufacturing (NAICS 325199)
 Pharmaceutical Preparations (e.g., Capsules, Liniments,
Ointments, Tablets) Manufacturing (NAICS 325412)
 Air Conditioning and Warm Air Heating Equipment and Commercial
and Industrial Refrigeration Equipment Manufacturing (NAICS 333415)
 Household Appliances, Electric Housewares, and Consumer
Electronics Merchant Wholesalers (NAICS 423620)
 Refrigeration Equipment and Supplies Merchant Wholesalers
(NAICS 423740)
 Recyclable Material Merchant Wholesalers (NAICS 423930)
 Appliance Repair and Maintenance (NAICS 811412)
 Fire Protection (NAICS 922160)

    This list is not intended to be exhaustive, but rather to provide a
guide for readers regarding entities likely to be affected by this
action. To determine whether your facility, company, business, or
organization could be affected by this action, you should carefully
examine the regulations at 40 CFR part 82, subpart G and the revisions
below. If you have questions regarding the applicability of this action
to a particular entity, consult the person listed in the FOR FURTHER
INFORMATION CONTACT section.

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

    Below is a list of acronyms and abbreviations used in the preamble
of this document:

2-BTP--2-bromo-3,3,3-trifluoropropene
AC--Air Conditioning or Air Conditioner
ACCA--Air Conditioning Contractors of America
ACGIH--American Conference of Governmental Industrial Hygienists
AEL--Acceptable Exposure Limit
AIHA--American Industrial Hygiene Association
AHRI--Air-Conditioning, Heating, and Refrigeration Institute
ANSI--American National Standards Institute
ASHRAE--American Society of Heating, Refrigerating and Air-
Conditioning Engineers
ASTM--American Society for Testing and Materials

CAA--Clean Air Act
CAS Reg. No.--Chemical Abstracts Service Registry Identification
Number
CBI--Confidential Business Information
CFC--Chlorofluorocarbon
CFR--Code of Federal Regulations
CO2--Carbon Dioxide
EPA--United States Environmental Protection Agency
FR--Federal Register
GWP--Global Warming Potential
HCFC--Hydrochlorofluorocarbon
HCFO--Hydrochlorofluoroolefin
HFC--Hydrofluorocarbon
HFO--Hydrofluoroolefin
HP--Heat Pump
ICF--ICF International, Inc.
IPCC--Intergovernmental Panel on Climate Change
LFL--Lower Flammability Limit
LOAEL--Lowest Observed Adverse Effect Level
NAAQS--National Ambient Air Quality Standards
NAICS--North American Industrial Classification System
NARA--National Archives and Records Administration
NFPA--National Fire Protection Association
NIOSH--National Institute for Occupational Safety and Health
NPRM--Notice of Proposed Rulemaking
ODP--Ozone Depletion Potential
ODS--Ozone Depleting Substances
OMB--United States Office of Management and Budget
OSHA--United States Occupational Safety and Health Administration
PMS--Pantone[supreg] Matching System
ppm--Parts Per Million
PRA--Paperwork Reduction Act
PTAC--Packaged Terminal Air Conditioner
PTHP--Packaged Terminal Heat Pump
RAL--``Reichs-Ausschu[szlig] f[uuml]r Lieferbedingungen und
G[uuml]tesicherung,'' Germany's National Commission for Delivery
Terms and Quality Assurance
RCRA--Resource Conservation and Recovery Act
RFA--Regulatory Flexibility Act
SCBA--Self-Contained Breathing Apparatus
SDS--Safety Data Sheet
SIP--State Implementation Plan
SNAP--Significant New Alternatives Policy
TLV-TWA--Threshold Limit Value-Time-Weighted Average
TSCA--Toxic Substances Control Act
TWA--Time Weighted Average
UL--UL, formerly known as Underwriters Laboratories, Inc.
UMRA--Unfunded Mandates Reform Act
VOC--Volatile Organic Compound, Volatile Organic Compounds
VSLS--Very Short-Lived Substances
VLTR--Very Low Temperature Refrigeration
WEEL--Workplace Environmental Exposure Limit
WMO--World Meteorological Organization

II. What is EPA proposing in this action?

A. Chillers--Proposed Listing of HFO-1234yf, R-454A, R-454B, and R-454C
as Acceptable, Subject to Use Conditions, for Use in New Chiller
Equipment, and Proposed Listing of HFC-32 and R-452B as Acceptable,
Subject to Use Conditions, for Use in New Rotary and Scroll Chiller
Equipment, for Chillers Used in Comfort Cooling, Including Both
Commercial and Industrial Process AC

    EPA previously listed HFO-1234yf as acceptable subject to use
conditions in motor vehicle AC in light-duty vehicles (74 FR 53445;
October 19, 2009), in heavy-duty pickup trucks and complete heavy-duty
vans (81 FR 86778; December 1, 2016) and in nonroad vehicles and
service fittings for small refrigerant cans (87 FR 26276; May 4, 2022).
EPA previously listed HFC-32 as acceptable subject to use conditions as
a substitute in residential and light commercial AC and HPs (80 FR
19454; April 10, 2015) (86 FR 24444; May 6, 2021) and previously listed
R-452B, R-454A, R-454B, and R-454C, (hereafter called ``the four
refrigerant blends''), as acceptable subject to use conditions as
substitutes in residential and light commercial AC and HPs (86 FR
24444; May 6, 2021).\1\
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    \1\ In this proposed rule, we use the term ``air conditioner''
and ``AC'' to cover equipment that cools air, heats air, or has the
function to do both (typically referred to as a ``heat pump'').
While such equipment might humidify or dehumidify the air, the term
does not include equipment whose purpose is for latent cooling only
(i.e., dehumidifiers), which are a separate end-use under SNAP and
are addressed in section II.B of this proposed rule.
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    Today's proposed rulemaking is proposing to find HFC-32, HFO-
1234yf, and the four refrigerant blends acceptable subject to use
conditions as substitutes in certain types of chillers. This proposed
listing for HFO-1234yf, R-454A, R-454B, and R-454C applies to all
compressor types of chillers, i.e., centrifugal and positive
displacement (including reciprocating, screw, scroll and rotary)
chillers, while the proposed listing for HFC-32 and R-452B applies to
only scroll and rotary chillers. The proposed listings are for comfort
cooling applications of such chillers under EPA's proposed use
conditions, including but not limited to use in commercial AC and
industrial process AC.
    Several use conditions proposed for chillers are identical to those
proposed for other end-uses (residential dehumidifiers, non-residential
dehumidifiers, and residential and light commercial AC and HPs)
proposed in sections II.B, II.C, and II.D. below. Because of this
similarity, EPA discusses the use conditions that would apply to all
three end-uses in section II.E below. For chillers, EPA is also
proposing an additional use condition related to adherence to the
ASHRAE 15-2019 standard. In summary, the common use conditions proposed
are:
    (1) New equipment only--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.
    (2) UL Standard--These refrigerants may be used only in chillers
that meet all requirements listed in the 3rd edition, dated November 1,
2019, of UL Standard 60335-2-40, ``Household and Similar Electrical
Appliances--Safety--Part 2-40: Particular Requirements for Electrical
Heat Pumps, Air Conditioners and Dehumidifiers'' (hereafter in this
section, ``UL Standard''). If this rule is finalized as proposed, in
cases where the final rule would include requirements different than
those of the 3rd edition of UL Standard 60335-2-40, EPA is proposing
that the appliance would need to meet the requirements of the final
rule in place of the requirements in the UL Standard. See section II.E
below for further discussion on the requirements of this standard that
EPA is proposing to incorporate by reference.
    (3) Warning labels--Several warning labels are proposed as use
conditions as detailed in section II.E below. These labels are similar
or verbatim in language to those required by the UL Standard. The
warning labels must be provided in letters no less than 6.4 mm (\1/4\
inch) high and must be permanent.
    (4) Markings--Equipment must have distinguishing red
(Pantone[supreg] Matching System (PMS) #185 or Reichs-Ausschu[szlig]
f[uuml]r Lieferbedingungen und G[uuml]tesicherung \2\ (RAL) 3020)
color-coded hoses and piping to indicate use of a flammable
refrigerant. The chiller shall have marked service ports, pipes, hoses
and other devices through which the refrigerant is serviced. Markings
shall extend at least 1 inch (25 millimeters) from the servicing port
and shall be replaced if removed.
---------------------------------------------------------------------------

    \2\ Germany's National Commission for Delivery Terms and Quality
Assurance.
---------------------------------------------------------------------------

    For chillers, EPA is also proposing a use condition related to
adherence to the ASHRAE 15-2019 standard in addition to those common
proposed use conditions. Specifically, we are proposing that these
refrigerants may only be used in chillers that meet all

requirements listed in the American National Standards Institute
(ANSI)/ASHRAE Standard 15-2019 (hereafter ``ASHRAE Standard''). If this
rule is finalized as proposed, in cases where the final rule would
include requirements different than those of ASHRAE Standard 15-
2019,\3\ EPA is proposing that the appliance would need to meet the
requirements of the final rule in place of the requirements in the
ASHRAE Standard. EPA is also proposing that if this rule is finalized
as proposed, in cases where similar requirements of ASHRAE Standard 15
and UL Standard 60335-2-40 differ, the more stringent or conservative
condition shall apply unless superseded by the final rule. This
additional use condition is discussed further in section II.A.4 below.
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    \3\ ASHRAE, 2019b. American National Standards Institute (ANSI)/
American Society for Heating, Refrigerating, and Air-Conditioning
Engineers (ASHRAE) Standard 15. Safety Standard for Refrigeration
Systems. 2019.
---------------------------------------------------------------------------

    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix X of 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for the end-uses discussed
above. EPA notes that there may be other legal obligations pertaining
to the manufacture, use, handling, and disposal of the proposed
refrigerants that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) prohibition on knowingly
venting or otherwise knowingly releasing or disposing of substitute
refrigerants in the course of maintaining, servicing, repairing or
disposing of an appliance or industrial process refrigeration or
Department of Transportation requirements for transport of flammable
gases). Flammable refrigerants being recovered or otherwise disposed of
from chillers are likely to be hazardous waste under the Resource
Conservation and Recovery Act (RCRA) (see 40 CFR parts 260-270).
1. Background on Chillers--Commercial AC and Industrial Process AC
    This proposal applies to chillers that are covered by the UL 60335-
2-40 standard ``Household and Similar Electrical Appliances--Safety--
Part 2-40: Requirements for Electrical Heat Pumps, Air Conditioners and
Dehumidifiers'' and ASHRAE Standard 15-2019, ``Safety Standard for
Refrigeration Systems.'' EPA understands that the UL Standard applies
to chillers used for comfort cooling.
    In the initial rule establishing the SNAP program (59 FR 13044;
March 18, 1994), EPA included within the refrigeration and AC sector
the end-use ``commercial comfort air conditioning'' and then elaborated
on that end-use by saying that ``CFCs are used in several different
types of mechanical commercial comfort AC systems, known as chillers.''
EPA indicated ``that over time, existing cooling capacity [from
chillers] will be either retrofitted or replaced by systems using non-
CFC refrigerants in a vapor compression cycle or by alternative
technologies.'' We also explained in that rule that vapor compression
chillers can be categorized by the type of compressor used, including
centrifugal, rotary, screw, scroll and reciprocating compressors. These
compressor types are also divided into centrifugal and positive
displacement chillers, the latter of which includes those with
reciprocating, screw, scroll or rotary compressors.
    Centrifugal chillers are equipment that utilize a centrifugal
compressor in a vapor-compression refrigeration cycle. Centrifugal
chillers are typically used for commercial comfort AC, although other
uses, that we are not proposing here, do exist. Centrifugal chillers
can be found in office buildings, hotels, arenas, convention halls,
airport terminals and other buildings. Centrifugal chillers tend to be
used in larger buildings.
    Positive displacement chillers are those that utilize positive
displacement compressors such as reciprocating, screw, scroll or rotary
types. Positive displacement chillers are applied in similar situations
as centrifugal chillers, again primarily for commercial comfort AC,
except that positive displacement chillers tend to be used for smaller
capacity needs such as in mid- and low-rise buildings.
    A chiller is a type of equipment using refrigerant that typically
cools water or a brine solution, which is then pumped to fan coil units
or other air handlers to cool the air that is supplied to the occupied
spaces transferring the heat to the water. The heat absorbed by the
water can then be used for heating purposes, and/or can be transferred
directly to the air (``air-cooled''), to a cooling tower or body of
water (``water-cooled''), or through evaporative coolers
(``evaporative-cooled''). A chiller or a group of chillers could
similarly be used for district cooling where the chiller plant cools
water or another fluid that is then pumped to multiple locations being
served such as several different buildings within the same complex.
Chillers may also be used to maintain operating temperatures in various
types of buildings, for example, in data centers, server farms, and
agricultural/food operations. Chillers are used in other applications,
for example, to cool process streams in industrial applications.
Chillers are also used for comfort cooling of operators or climate
control and protecting process equipment in industrial buildings, for
example, in industrial processes when ambient temperatures could
approach 200 [deg]F (93 [deg]C) and corrosive conditions could exist.
The listings proposed today would apply to all types of chillers in
comfort cooling applications.
2. What are the American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE) classifications for refrigerant
flammability?
    The ANSI/ASHRAE Standard 34-2019 assigns a safety group
classification for each refrigerant which consists of two to three
alphanumeric characters (e.g., A2L or B1). The initial 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, 2L, or 3. Tests for flammability are conducted in accordance with
American Society for Testing and Materials (ASTM) E681 using a spark
ignition source at 140 [deg]F (60 [deg]C) and 14.7 psia (101.3 kPa).\4\
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 (8,169
Btu/lb), and have a lower flammability limit (LFL) greater than 0.10
kg/m\3\. The flammability classification ``2L'' is given to
refrigerants that, when tested, exhibit flame propagation, have a heat
of combustion less than 19,000 kJ/kg (8,169 BTU/lb), have an LFL
greater than 0.10 kg/m\3\, and have a maximum burning velocity of 10
cm/s or lower

when tested in dry air at 73.4 [deg]F (23.0 [deg]C) and 14.7 psi (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 (8,169 BTU/lb) or greater or have an
LFL of 0.10 kg/m\3\ or lower.
---------------------------------------------------------------------------

    \4\ ASHRAE, 2019a. ANSI/ASHRAE Standard 34-2019: Designation and
Safety Classification of Refrigerants.
---------------------------------------------------------------------------

    For flammability classifications, refrigerant blends are designated
based on the worst case of formulation for flammability and the worst
case of fractionation for flammability determined for the blend.
[GRAPHIC] [TIFF OMITTED] TP28JY22.000

    Using these safety group classifications, ANSI/ASHRAE Standard 34-
2019 categorizes HFO-1234yf, HFC-32 and the four refrigerant blends in
this section of the proposed rulemaking in the A2L Safety Group.
3. What are HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-454C and
how do they compare to other refrigerants in the same end-use?
    HFO-1234yf and HFC-32 are lower flammability refrigerants, and the
four refrigerant blends are lower flammability refrigerant blends, all
with an ASHRAE safety classification of A2L. The respective Chemical
Abstracts Service Registry Identification Numbers (CAS Reg. Nos.) of
HFO-1234yf, HFC-32 and the components of the four refrigerant blends
are listed below.
    HFO-1234yf, also known by the trade names ``Solstice[supreg] yf''
and ``Opteon TM YF,'' is also known as 2,3,3,3-
tetrafluoroprop-1-ene (CAS Reg. No. 754-12-1). HFC-32 is also known as
R-32 or difluoromethane (CAS Reg. No. 75-10-5). R-452B, also known by
the trade names ``Opteon TM XL 55'' and ``Solstice[supreg]
L41y,'' is a blend consisting of 67 percent by weight HFC-32; seven
percent HFC-125, also known as 1,1,1,2,2-pentafluoroethane (CAS Reg.
No. 354-33-6); and 26 percent HFO-1234yf. R-454A, also known by the
trade name ``OpteonTM XL 40,'' is a blend consisting of 35
percent HFC-32 and 65 percent HFO-1234yf. R-454B, also known by the
trade names ``OpteonTM XL 41'' and ``Puron
AdvanceTM,'' is a blend consisting of 68.9 percent HFC-32
and 31.1 percent HFO-1234yf. R-454C, also known by the trade name
``OpteonTM XL 20,'' is a blend consisting of 21.5 percent
HFC-32 and 78.5 percent HFO-1234yf.
    Redacted submissions and supporting documentation for HFO-1234yf,
HFC-32 and the four refrigerant blends are provided in the docket for
this proposed rule (EPA-HQ-OAR-2021-0836) at https://www.regulations.gov. EPA performed an assessment to examine the health
and environmental risks of each of these substitutes. These assessments
are available in the docket for this proposed
rule.5 6 7 8 9 10
---------------------------------------------------------------------------

    \5\ ICF, 2022a. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute: R-
32.
    \6\ ICF, 2022b. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute:
HFO-123yf.
    \7\ ICF, 2022c. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute: R-
452B.
    \8\ ICF, 2022d. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute: R-
454A.
    \9\ ICF, 2022e. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute: R-
454B.
    \10\ ICF, 2022f. Risk Screen on Substitutes in Chillers and
Industrial Process Air Conditioning (New Equipment); Substitute: R-
454C.
---------------------------------------------------------------------------

    Environmental information: HFO-1234yf, HFC-32 and the four
refrigerant blends have ODPs of zero.
    HFO-1234yf has a 100-year integrated global warming potential (GWP)
of less than one to four. 11 12 13 HFC-32 has a GWP of 675.
The four refrigerant blends are made up of the components HFC-32, HFC-
125, and HFO-1234yf, which have GWPs of 675, 3,500, and one to four,
respectively.\14\ If these values are weighted by mass percentage, then
R-452B, R-454A, R-454B, and R-454C have GWPs of about 700, 240, 470,
and 150, respectively.
---------------------------------------------------------------------------

    \11\ World Meteorological Organization (2018). Burkholder et al.
Appendix A, Table A-1 in Scientific Assessment of Ozone Depletion:
2018, Global Ozone Research and Monitoring Project, Report No. 58,
World Meteorological Organization, Geneva, Switzerland, http://ozone.unep.org/science/assessment/sap. (WMO, 2018).
    \12\ Nielsen et al., 2007. Nielsen, O.J., Javadi, M.S., Sulbaek
Andersen, M.P., Hurley, M.D., Wallington, T.J., Singh, R. 2007.
Atmospheric chemistry of CF3CF=CH2: Kinetics and mechanisms of gas-
phase reactions with Cl atoms, OH radicals, and O3. Chemical Physics
Letters 439, 18-22. Available online at http://www.cogci.dk/network/OJN_174_CF3CF=CH2.pdf.
    \13\ Hodnebrog [Oslash];. et al., 2013. Hodnebrog [Oslash];.,
Etminan, M., Fuglestvedt, J.S., Marston, G., Myhre, G., Nielsen,
C.J., Shine, K.P., Wallington, T.J.: Global Warming Potentials and
Radiative Efficiencies of Halocarbons and Related Compounds: A
Comprehensive Review, Reviews of Geophysics, 51, 300-378,
doi:10.1002/rog.20013, 2013.
    \14\ Unless otherwise specified, GWP values are 100-year values
from Intergovernmental Panel on Climate Change (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. S. Solomon, D. Qin, M. Manning, Z. Chen, M.
Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.). Cambridge
University Press. Cambridge, United Kingdom 996 pp.
---------------------------------------------------------------------------

    HFC-32, HFO-1234yf, and the other component of one of the four
refrigerant

blends, HFC-125, are excluded from EPA's regulatory definition of
volatile organic compounds (VOC) (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). That definition
provides that ``any compound of carbon'' which ``participates in
atmospheric photochemical reactions'' is considered a VOC unless
expressly excluded in that provision based on a determination of
``negligible photochemical reactivity.'' Knowingly venting or otherwise
knowingly releasing or disposing of these refrigerants in the course of
maintaining, servicing, repairing or disposing of an appliance or
industrial process refrigeration is prohibited as provided in section
608(c)(2) of the CAA and EPA's regulations at 40 CFR 82.154(a)(1).
    Flammability information: HFO-1234yf, HFC-32 and the four
refrigerant blends have lower flammability. All have an ASHRAE
flammability classification of 2L.
    Toxicity and exposure data: HFO-1234yf, HFC-32 and the four
refrigerant blends have an ASHRAE toxicity classification of A.
Potential health effects of exposure to these substitutes include
drowsiness or dizziness. The substitutes may also irritate the skin or
eyes or cause frostbite. At sufficiently high concentrations, the
substitutes may cause irregular heartbeat. The substitutes could cause
asphyxiation if air is displaced by vapors in a confined space. These
potential health effects are common to many refrigerants.
    The American Industrial Hygiene Association (AIHA) has established
Workplace Environmental Exposure Limits (WEELs) of 1,000 ppm as an
eight-hour time-weighted average (8-hr TWA) for HFC-32 and the
component refrigerant HFC-125; the AIHA has established a WEEL of 500
ppm as an 8-hr TWA for HFO-1234yf. The manufacturer of R-452B, R-454A,
R-454B, and R-454C recommends AELs, respectively, of 874, 690, 854, and
615 ppm on an 8-hr TWA for these blends. EPA anticipates that users
will be able to meet the AIHA WEELs and manufacturers' AELs and address
potential health risks by following requirements and recommendations in
the manufacturers' safety data sheet (SDS), the use conditions proposed
(including adherence to ASHRAE Standard 15), and other safety
precautions common to the refrigeration and AC industry.
    Comparison to other substitutes in this end-use: HFO-1234yf, HFC-32
and the four refrigerant blends all have an ODP of zero, comparable to
or lower than some of the acceptable substitutes in these end-uses,
such as HFO-1234ze(E) with an ODP of zero. Although HCFC-123 and R-406A
(with components HCFC-22 and HCFC-142b) have been listed acceptable in
this end-use with ODPs of 0.02 and 0.057, respectively, HCFC-123
(unless used, recovered, and recycled) may not be used as a refrigerant
in equipment manufactured on or after January 1, 2020, under 40 CFR
82.15(g)(5)(i).\15\ Similarly, components of R-406A (HCFC-22 and HCFC-
142b) (unless used, recovered, and recycled) may not be used as a
refrigerant for use in chillers manufactured on or after January 1,
2010, under 40 CFR 82.15(g)(2)(i).\16\ Under 40 CFR 82.16, EPA has not
issued any production and consumption allowances for HCFC-22 and HCFC-
142b since 2019.
---------------------------------------------------------------------------

    \15\ The regulations at 40 CFR 82.15(g)(5)(iii) provide a
limited exception to the prohibition on use in 82.15(g)(5)(i), for
use of HCFC-123 as a refrigerant in equipment manufactured on or
after January 1, 2020 but before January 1, 2021 if the conditions
of 40 CFR 82.15(g)(5)(iii) are met.
    \16\ The regulations at 40 CFR 82.15(g)(2)(ii) provide limited
exceptions to the prohibitions in 82.15(g)(2)(i), including for
HCFC-22 ``for use as a refrigerant in appliances manufactured before
January 1, 2012, provided that the components are manufactured prior
to January 1, 2010, and are specified in a building permit or a
contract dated before January 1, 2010, for use on a particular
project.''
---------------------------------------------------------------------------

    HFC-32 and the four refrigerant blends' GWPs, ranging from about
150 to 700, are higher than those of some of the acceptable substitutes
for new centrifugal and positive displacement chillers, including HCFO-
1233zd(E), HFO-1336mzz(Z) and R-515B, with GWPs of 3.7, 9 and 287,
respectively. The GWPs of HFO-1234yf, R-454A, R-454B, and R-454C are
lower than some of the acceptable substitutes for new centrifugal and
positive displacement chillers, such as R-450A and R-513A, with GWPs of
approximately 600 and 630, respectively. For scroll and rotary
chillers, HFC-32's and R-452B's GWPs of 675 and about 700 are higher
than the GWPs of those refrigerants. The GWPs of HFC-32 and R-452B are,
however, lower than R-410A, with a GWP of approximately 2,090, which is
the refrigerant that has typically been employed in such systems. EPA
listed R-410A as unacceptable for chillers as of January 1, 2024. Our
initial evaluation is that the characteristics of these two
alternatives meet the technical needs of scroll and rotary chillers
while lower-GWP alternatives do not. For instance, under the Air-
Conditioning, Heating, and Refrigeration Institute's (AHRI) Low-GWP
Alternative Refrigerants Evaluation Program, manufacturers specifically
chose HFC-32 amongst others to test in scroll chillers \17\ but not in
screw chillers.\18\ EPA understands that the decision to investigate
this refrigerant in scroll chillers was made because it has the higher
volumetric capacity that is needed for this type of compressor. This
thermodynamic property is important to achieve the cooling capacity
needed without increasing equipment sizes, which could lead to weights
exceeding code requirements, for instance, when a chiller on top of an
existing building is replaced with a new one. In contrast, for other
types of compressors, such as centrifugal, reciprocating, and screw,
the higher volumetric capacity is not required; lower-GWP refrigerants,
such as HCFO-1233zd(E), R-450A, and R-513A, with GWPs ranging from less
than one to 630, are available and meet technical needs for those
compressor types.
---------------------------------------------------------------------------

    \17\ For example, test report #46 (https://ahrinet.org/App_Content/ahri/files/RESEARCH/AREP_Final_Reports/AHRI%20Low-GWP%20AREP-Rpt-046.pdf).
    \18\ For example, test report #7 (https://ahrinet.org/App_Content/ahri/files/RESEARCH/AREP_Final_Reports/AHRI%20Low-GWP%20AREP-Rpt-024.pdf) and test report #25 (https://ahrinet.org/App_Content/ahri/files/RESEARCH/AREP_Final_Reports/AHRI%20Low-GWP%20AREP-Rpt-025.pdf).
---------------------------------------------------------------------------

    HFC-32's and the four refrigerant blends' GWPs, ranging from about
150 to 700, are higher than those of some of the acceptable substitutes
for new industrial process AC, including carbon dioxide
(CO2), HFO-1336mzz(Z) and R-515B with GWPs of 1, 9 and 287
respectively. Their GWPs are lower than some of the acceptable
substitutes for new industrial process AC, such as HFC-134a, R-410A,
and R-507A with GWPs of 1,430, 2,090 and 3,990 respectively. HFO-
1234yf's GWP of one to four is comparable to or lower than that of
other acceptable substitutes for new industrial process AC, such as
CO2, HFO-1336mzz(Z) and R-515B with GWPs of 1, 9 and 287,
respectively.
    Information regarding the toxicity of other available alternatives
is provided in the listing decisions previously made (see https://www.epa.gov/snap/substitutes-chillers). Toxicity risks of use,
determined by the likelihood of exceeding the exposure limit, of HFO-
1234yf, HFC-32, and the four refrigerant blends in these end-uses are
evaluated in the risk screens referenced above. The toxicity risks of
using HFO-1234yf, HFC-32, and the four refrigerant blends in chillers
and industrial process AC are comparable to or lower than toxicity
risks of other available substitutes in the same end-uses. Toxicity
risks of the

proposed refrigerants can be minimized by use consistent with ASHRAE
15--which would be required by our proposed use conditions--and other
industry standards, recommendations in the manufacturers' SDS, and
other safety precautions common in the refrigeration and AC industry.
    The flammability risk with HFO-1234yf, HFC-32, and the four
refrigerant blends in these end-uses, determined by the likelihood of
exceeding their respective lower flammability limits, are evaluated in
the risk screens referenced above. In conclusion, while these
refrigerants may pose greater flammability risk than other available
substitutes in the same end-uses, this risk can be minimized by use
consistent with ASHRAE 15--which would be required by our proposed use
conditions--and other industry standards such as UL 60335-2-40--which
is also required by our proposed use conditions--as well as
recommendations in the manufacturers' SDS and other safety precautions
common in the refrigeration and AC industry. EPA is proposing use
conditions to reduce the potential risk associated with the
flammability of these alternatives so that they will not pose
significantly greater risk than other acceptable substitutes in this
end-use.
4. Why is EPA proposing these specific use conditions?
    The UL Standard 60335-2-40 discussed in section II.E indicates that
refrigerant charges greater than a specific amount (called
``m3'' in the UL Standard and based on the refrigerant's
LFL) are beyond its scope and that national standards might apply, such
as for instance ANSI/ASHRAE 15-2019. Hence, EPA is including adherence
to both standards as use conditions for chillers, broadening the
coverage under this proposed rule.
    EPA is proposing that ANSI/ASHRAE Standard 15-2019, with all
addenda published to date of this proposal, including addenda a, b, c,
d, e, f, i, j, k, n, o, q, and r apply specifically to chillers. Where
the requirements specified in this proposed rule (if finalized) and
ASHRAE Standard 15 are different, the requirements of this proposed
rule (if finalized) would apply. In cases where similar requirements of
ASHRAE Standard 15 and UL Standard 60335-2-40 differ, EPA proposes that
the more stringent or conservative condition would apply.
    A summary of certain aspects of ASHRAE Standard 15 is provided here
for information only. This is not meant to be a full explanation of the
Standard or how it is applied. ASHRAE Standard 15 specifies
requirements for refrigeration systems,\19\ including chillers, based
on the safety group classification of the refrigerant used, the type of
occupancy in the location for which the system is used, and whether
refrigerant-containing parts of the system enter the space or ductwork
and so leakage in the space is deemed ``probable.'' ``High-
Probability'' installations are those such that leaks or failures will
result in refrigerant entering the occupied space. As explained above,
HFO-1234yf, HFC-32 and the four refrigerant blends are all classified
as A2L refrigerants. Occupancies are divided into six classifications:
institutional, public assembly, residential, commercial, large
mercantile, and industrial. Examples of these include jails, theaters,
apartment buildings, office buildings, shopping malls, and chemical
plants, respectively.
---------------------------------------------------------------------------

    \19\ We note that while the ASHRAE 15-2019 purpose indicates
``refrigeration systems,'' EPA believes this includes applications
that are typically called ``air conditioning.''
---------------------------------------------------------------------------

    Sections 7.2 and 7.3 of ASHRAE Standard 15 determine the maximum
amount of refrigerant allowed in the system, while section 7.4 provides
an option to locate equipment outdoors or in a machinery room
constructed and maintained under conditions specified in the standard.
Section 7.6 of ASHRAE Standard 15 addresses the refrigerants in this
proposal when used for human comfort in ``high-probability'' systems,
including requirements for nameplates, labels, refrigerant detectors
(under certain conditions), airflow initiation and other actions (if a
rise in refrigerant concentration is detected), and other restrictions.
    EPA recognizes that ASHRAE Standard 15 is undergoing revisions and
is typically updated and republished every three years. While this
proposed rule incorporates all addenda published by the date of this
proposal, the 2022 version of the standard may incorporate additional
changes. ASHRAE standards are open for public comment and participation
following ANSI requirements.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. See section II.E.2 below
for further discussion on what additional information EPA is including
in these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision above for use of HFC-32 and R-452B in scroll and rotary
chillers. EPA is also requesting comment on the proposal to list HFO-
1234yf, R-454A, R-454B, and R-454C acceptable in all chillers. We
request comment on our initial evaluation and our proposal to find HFC-
32 and R-452B acceptable, subject to use conditions, for use only in
scroll and rotary chillers. EPA also seeks specific comments on the use
conditions including the proposed requirements to comply with both the
third edition of UL Standard 60335-2-40 and ASHRAE 15-2019 including
published addenda. With respect to these standards, EPA is requesting
comment on the risk mitigation offered by compliance with the current
version of the standards proposed as use conditions, the nature of
updates proposed for these standards, and the expected timeline for
those updates. EPA is requesting comment on the applicability of UL
Standard 60335-2-40, 3rd Edition to chillers, including which chillers
and under which applications the standard applies, as well as on the
applicability of ASHRAE Standard 15-2019 with the addenda published to
date.
    EPA recognizes that these standards are undergoing revision. Both
UL and ASHRAE standards are open for public comment and participation
following ANSI requirements. UL opened for comment a proposed 4th
edition of this standard as an update to the 3rd Edition to which
comments were due March 1, 2022. If the final 4th edition is published
before EPA takes final action on today's proposed listings that would
incorporate the 3rd edition by reference, EPA may incorporate the 4th
Edition by reference into those listings in lieu of the 3rd Edition.
Similarly, ASHRAE has opened for comment a 2022 version of ANSI/ASHRAE
15. If the final 2022 edition of ASHRAE 15 is published before EPA
takes final action on today's proposed listings that would incorporate
the 2019 edition by reference, EPA may incorporate the 2022 edition by
reference into those listings in lieu of the 2019 edition. If either
revised standard becomes final before EPA takes final action on these

listings, EPA anticipates reopening or extending the public comment
period to provide an opportunity for public comment on incorporating
the final 4th edition of UL 60335-2-40 or the final 2022 edition of
ASHRAE 15 by reference into those listings.

B. Residential Dehumidifiers--Proposed Listing of HFO-1234yf, HFC-32,
R-452B, R-454A, R-454B, and R-454C as Acceptable, Subject to Use
Conditions, for Use in New Residential Dehumidifiers End-Use

    EPA previously listed HFO-1234yf as acceptable subject to use
conditions in motor vehicle AC in light-duty vehicles (74 FR 53445;
October 19, 2009), in heavy-duty pickup trucks and complete heavy-duty
vans (81 FR 86778; December 1, 2016) and in nonroad vehicles and
service fittings for small refrigerant cans (87 FR 26276; May 4, 2022).
EPA previously listed HFC-32 as acceptable subject to use conditions as
a substitute in residential and light commercial AC and HPs (80 FR
19454; April 10, 2015 and 86 FR 24444, May 6, 2021) and previously
listed R-452B, R-454A, R-454B, and R-454C (hereafter called ``the four
refrigerant blends'') as acceptable subject to use conditions as
substitutes in residential and light commercial AC and HPs (86 FR
24444; May 6, 2021).
    Several use conditions proposed for residential dehumidifiers are
common to those proposed for other end-uses in section II.A, above, and
II.C and II.D, below. Because of this similarity, EPA discusses the use
conditions that would apply to all four end-uses in section II.E. For
residential dehumidifiers, those are the only use conditions EPA is
proposing. In summary the use conditions proposed are:
    (1) New equipment only--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.
    (2) UL Standard--These refrigerants may be used only in residential
dehumidifiers that meet all requirements listed in the 3rd edition,
dated November 1, 2019, of Underwriters Laboratories (UL) Standard
60335-2-40, ``Household and Similar Electrical Appliances--Safety--Part
2-40: Particular Requirements for Electrical Heat Pumps, Air
Conditioners and Dehumidifiers'' (UL Standard). If this rule is
finalized as proposed, in cases where the final rule would include
requirements different from those of the 3rd edition of UL Standard
60335-2-40, EPA is proposing that the appliance would need to meet the
requirements of the final rule in place of the requirements in the UL
Standard. See section II.E below for further discussion on the
requirements of this standard that EPA is proposing to incorporate by
reference.
    (3) Warning labels--Several warning labels are proposed as use
conditions as detailed in section II.E below. These labels are similar
or verbatim in language to those required by the UL Standard. The
warning labels must be provided in letters no less than 6.4 mm (\1/4\
inch) high and must be permanent.
    (4) Markings--Equipment must have distinguishing red (PMS #185 or
RAL 3020) color-coded hoses and piping to indicate use of a flammable
refrigerant. The residential dehumidifier shall have marked service
ports, pipes, hoses and other devices through which the refrigerant is
serviced. Markings shall extend at least 1 inch (25mm) from the
servicing port and shall be replaced if removed.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix X of 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for the end-use discussed
above. EPA notes that there may be other legal obligations pertaining
to the manufacture, use, handling, and disposal of the proposed
refrigerants that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) prohibition on knowingly
venting or otherwise knowingly releasing or disposing of substitute
refrigerants in the course of maintaining, servicing, repairing or
disposing of an appliance or industrial process refrigeration, or
Department of Transportation requirements for transport of flammable
gases). Flammable refrigerants being recovered or otherwise disposed of
from residential dehumidifiers are likely to be hazardous waste under
RCRA (see 40 CFR parts 260-270).
1. Background on Residential Dehumidifiers
    Residential dehumidifiers are primarily used to remove water vapor
from ambient air or directly from indoor air for comfort or material
preservation purposes in the context of the home.\20\ While AC systems
often combine cooling and dehumidification, this end-use only serves
the latter purpose and is often used in homes for comfort purposes.
This equipment is self-contained and circulates air from a room, passes
it through a cooling coil, and collects condensed water for disposal.
Residential dehumidifiers fall under the scope of the UL 60335-2-40
standard ``Household and Similar Electrical Appliances--Safety--Part 2-
40: Requirements for Electrical Heat Pumps, Air Conditioners and
Dehumidifiers.''
---------------------------------------------------------------------------

    \20\ SNAP regulations (see 40 CFR 82.172) define residential use
as use by a private individual of a chemical substance or any
product containing the chemical substance in or around a permanent
or temporary household, during recreation, or for any personal use
or enjoyment. Use within a household for commercial or medical
applications is not included in this definition, nor is use in
automobiles, watercraft, or aircraft.
---------------------------------------------------------------------------

    Some dehumidifiers for residential or light commercial use are
integrated with the space air conditioning equipment, for instance via
a separate bypass in the duct through which air is dehumidified, a
dehumidifying heat pipe across the indoor coil, or other types of
energy recovery devices that move sensible and/or latent heat between
air streams (e.g., between incoming air and air vented to the outside).
EPA classifies this application as a component of a residential or
light commercial AC system or HP. As such, EPA has already listed HFC-
32 as acceptable for such uses, subject to the use conditions specified
in SNAP Rule 23 (86 FR 24444; May 6, 2021).
    Today's proposal, if finalized, would find HFO-1234yf, HFC-32, and
the four refrigerant blends acceptable, subject to use conditions, in
self-contained residential dehumidifiers. Note that dehumidifiers for
residential or light commercial use that are integrated with air
conditioning equipment (i.e., not self-contained), are not addressed in
this listing because EPA classifies that type of equipment as
residential or light commercial AC and HP.
2. What are the ASHRAE classifications for refrigerant flammability?
    HFO-1234yf and HFC-32 are lower flammability refrigerants, and the
four refrigerant blends are lower flammability refrigerant blends, all
with an ASHRAE safety classification of A2L. See section II.A.2 above
for further discussion on ASHRAE classifications.
3. What are HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-454C and
how do they compare to other refrigerants in the same end-use?
    See section II.A.3 above for further discussion on the
environmental, flammability, toxicity, and exposure information for
these refrigerants.
    Redacted submissions and supporting documentation for HFO-1234yf,
HFC-32 and the four refrigerant blends are provided in the docket for
this proposed rule (EPA-HQ-OAR-2021-0836) at

https://www.regulations.gov. EPA performed an assessment to examine the
health and environmental risks of each of these substitutes. These
assessments are available in the docket for this proposed
rule.21 22 23 24 25 26
---------------------------------------------------------------------------

    \21\ ICF, 2022g. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: HFC-32.
    \22\ ICF, 2022h. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: R-452B.
    \23\ ICF, 2022i. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: R-454A.
    \24\ ICF, 2022j. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: R-454B.
    \25\ ICF, 2022k. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: R-454C.
    \26\ ICF, 2022l. Risk Screen on Substitutes in Residential
Dehumidifiers (New Equipment); Substitute: HFO-1234yf.
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: HFO-1234yf, HFC-32
and the four refrigerant blends all have an ODP of zero, comparable to
or lower than some of the acceptable substitutes in new residential
dehumidifiers, such as HFC-134a, R-410A, and R-513A, with ODPs of zero.
HCFC-22 and R-406A (a blend of HCFC-22 and HCFC-142b) have ODPs of
0.055 and 0.057, respectively, and are listed as acceptable in new
residential dehumidifiers. However, HCFC-22 and HCFC-142b are
controlled substances under Title VI of the CAA and (unless used,
recovered, and recycled) may not be used as a refrigerant in equipment
manufactured on or after January 1, 2010, under 40 CFR
82.15(g)(2)(i).\27\ Under 40 CFR 82.16, EPA has not issued any
production and consumption allowances for HCFC-22 and HCFC-142b (which
is a component of R-406A, along with HCFC-22) since 2019.
---------------------------------------------------------------------------

    \27\ The regulations at 40 CFR 82.15(g)(2)(ii) provide limited
exceptions to the prohibitions in 82.15(g)(2)(i), including for
HCFC-22 ``for use as a refrigerant in appliances manufactured before
January 1, 2012, provided that the components are manufactured prior
to January 1, 2010, and are specified in a building permit or a
contract dated before January 1, 2010, for use on a particular
project.''
---------------------------------------------------------------------------

    HFO-1234yf, R-454A, R-454B, and R-454C have GWPs ranging up to
about 470, lower than all the acceptable substitutes for new
residential dehumidifiers, including R-513A and R-410A with GWPs of 630
and 2,090, respectively. HFC-32 and R-452B have GWPs of 675 and 700,
respectively, which are lower than some of the other acceptable
substitutes for new residential dehumidifiers, such as HFC-134a, R-
410A, and R-507A with GWPs of 1,430, 2,090 and 3,990 respectively, but
higher than R-513A, with a GWP of about 630.
    Information regarding the toxicity of other available alternatives
is provided in the previous listing decisions for new residential
dehumidifiers (https://www.epa.gov/snap/substitutes-residential-dehumidifiers). Toxicity risks of use, determined by the likelihood of
exceeding the exposure limit, of HFO-1234yf, HFC-32, and the four
refrigerant blends in these end-uses are evaluated in the risk screens
referenced above. The toxicity risks of using HFO-1234yf, HFC-32, and
the four refrigerant blends in new residential dehumidifiers are
comparable to or lower than toxicity risks of other available
substitutes in the same end-use. Toxicity risks of the proposed
refrigerants can be mitigated by use consistent with ASHRAE 15 and
other industry standards, recommendations in the manufacturers' SDS,
and other safety precautions common in the refrigeration and AC
industry.
    The flammability risk with HFO-1234yf, HFC-32, and the four
refrigerant blends in the new residential dehumidifiers end-use,
determined by the likelihood of exceeding their respective lower
flammability limits, are evaluated in the risk screens referenced in
this section above. While these refrigerants may pose greater
flammability risk than other available substitutes in the new
residential dehumidifiers end-use, this risk can be mitigated by use
consistent with ASHRAE 15 and UL 60335-2-40, required by our proposed
use conditions, as well as recommendations in the manufacturers' SDS
and other safety precautions common in the refrigeration and AC
industry. EPA is proposing use conditions to reduce the potential risk
associated with the flammability of these alternatives so that they
will not pose significantly greater risk than other acceptable
substitutes in the new residential dehumidifiers end-use.
4. Why is EPA proposing these specific use conditions?
    EPA is proposing to list HFO-1234yf, HFC-32 and the four
refrigerant blends as acceptable, subject to use conditions, for use in
residential dehumidifiers for new equipment. The use conditions
identified in the listing above are explained below in section II.E.1
in greater detail.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. See section II.E.2 below
for further discussion on what additional information EPA is including
in these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision in section II.B above, proposing to find HFO-1234yf, HFC-32,
and the four refrigerant blends acceptable, subject to use conditions,
in new residential dehumidifiers. EPA seeks comment on the risk
mitigation offered by the use conditions proposed, including requiring
compliance with the third edition of UL Standard 60335-2-40, except to
the extent the proposed rule conflicts with the UL Standard, in which
case we propose that the conditions specified in the proposed rule
would apply if finalized. We also request comment on whether EPA should
consider other use conditions to further mitigate potential risk from
refrigerants. EPA requests comment on whether residential dehumidifiers
have been designed for the refrigerants proposed and any information on
the safety of such equipment in other countries, and if and how such
experience would translate to safe use in the United States. EPA also
requests comment on our description of different types of dehumidifiers
and how EPA classifies different types in different end-uses.

C. Non-Residential Dehumidifiers--Proposed Listing of HFC-32 as
Acceptable, Subject to Use Conditions, for Use in New Non-Residential
Dehumidifiers End-Use

    EPA is proposing to list HFC-32 as acceptable, subject to use
conditions for use in new non-residential dehumidifiers. EPA previously
listed HFC-32 as acceptable subject to use conditions as a substitute
in residential and light commercial AC and HPs (80 FR 19454; April 10,
2015 and 86 FR 24444, May 6, 2021).
    The use conditions proposed for non-residential dehumidifiers are
the same as those proposed for residential dehumidifiers. The use
conditions are common to those proposed for other end-uses in section
II.A and II.B, above, and II.D, below. Because of this similarity, EPA
discusses the use

conditions that would apply to all four end-uses in section II.DE. In
summary, the use conditions proposed are:
    (1) New equipment only--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.
    (2) UL Standard--These refrigerants may be used only in non-
residential dehumidifiers that meet all requirements for dehumidifiers
listed in the 3rd edition, dated November 1, 2019, of Underwriters
Laboratories (UL) Standard 60335-2-40, ``Household and Similar
Electrical Appliances--Safety--Part 2-40: Particular Requirements for
Electrical Heat Pumps, Air Conditioners and Dehumidifiers'' (UL
Standard). If this rule is finalized as proposed, in cases where the
final rule would include requirements different from those of the 3rd
edition of UL Standard 60335-2-40, EPA is proposing that the appliance
would need to meet the requirements of the final rule in place of the
requirements in the UL Standard. See section II.E below for further
discussion on the requirements of this standard that EPA is proposing
to incorporate by reference.
    (3) Warning labels--Several warning labels are proposed as use
conditions as detailed in section II.E below. These labels are similar
or verbatim in language to those required by the UL Standard. The
warning labels must be provided in letters no less than 6.4 mm (\1/4\
inch) high and must be permanent.
    (4) Markings--Equipment must have distinguishing red (PMS #185 or
RAL 3020) color-coded hoses and piping to indicate use of a flammable
refrigerant. The non-residential dehumidifier shall have marked service
ports, pipes, hoses and other devices through which the refrigerant is
serviced. Markings shall extend at least 1 inch (25mm) from the
servicing port and shall be replaced if removed.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified in appendix X of 40 CFR part 82, subpart G. The proposed
regulatory text contains listing decisions for the end-use discussed
above. EPA notes that there may be other legal obligations pertaining
to the manufacture, use, handling, and disposal of the proposed
refrigerants that are not included in the information listed in the
tables (e.g., the CAA section 608(c)(2) prohibition on knowingly
venting or otherwise knowingly releasing or disposing of substitute
refrigerants in the course of maintaining, servicing, repairing or
disposing of an appliance or industrial process refrigeration, or
Department of Transportation requirements for transport of flammable
gases). Flammable refrigerants being recovered or otherwise disposed of
from non-residential dehumidifiers are likely to be hazardous waste
under RCRA (see 40 CFR parts 260-270).
1. Background on Non-Residential Dehumidifiers
    Today's proposal would create a new SNAP end-use for non-
residential dehumidifiers. As described in section II.B.1 above, while
AC systems often combine cooling and dehumidification, the non-
residential dehumidifier end-use serves only the latter purpose. This
equipment is self-contained and circulates air from a room, passes it
through a cooling coil, and collects condensed water for disposal. Non-
residential dehumidifiers are similar in function to residential
dehumidifiers described in section II.B.1 above, but are used in spaces
not covered by residential use (see definition provided in section
II.B.1 above). These types of non-residential spaces include
commercial, industrial, or agricultural spaces (e.g., grow-rooms for
plants) to provide finely controlled environments with temperature and
humidity monitored carefully to ensure optimal conditions (e.g., plant
growth). Examples of non-residential settings where self-contained
dehumidifiers are used include food production and preparation where
excessive humidity could damage the product or to manage humidity in
greenhouses to protect crops. This type of equipment falls under the
scope of the UL 60335-2-40 standard ``Household and Similar Electrical
Appliances--Safety--Part 2-40: Requirements for Electrical Heat Pumps,
Air Conditioners and Dehumidifiers.''
2. What are the ASHRAE classifications for refrigerant flammability?
    HFC-32 is a lower flammability refrigerant with an ASHRAE safety
classification of A2L. See section II.A.2 above for further discussion
on ASHRAE classifications.
3. What is HFC-32 and how does it compare to other refrigerants in the
same end-use?
    See section II.A.3 above for further discussion on the
environmental, flammability, toxicity and exposure information for HFC-
32.
    The redacted submission and supporting documentation for HFC-32 is
provided in the docket for this proposed rule (EPA-HQ-OAR-2021-0836) at
https://www.regulations.gov. EPA performed an assessment to examine the
health and environmental risks of this substitute. This assessment is
available in the docket for this proposed rule.\28\
---------------------------------------------------------------------------

    \28\ ICF, 2022m. Risk Screen on Substitutes in Non-residential
Dehumidifiers (New Equipment); Substitute: HFC-32.
---------------------------------------------------------------------------

    Because EPA is proposing new non-residential self-contained
dehumidifiers as a new end-use, there are no other listed substitutes
to compare to HFC-32.
4. Why is EPA proposing these specific use conditions?
    The use conditions identified in the listing above are explained
below in section II.E.1 in greater detail.
5. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. See section II.E.2 below
for further discussion on what additional information EPA is including
in these proposed listings. 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.
6. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed listing
decision in section II.C above, proposing to find HFC-32 acceptable,
subject to use conditions, in non-residential dehumidifiers. EPA seeks
comment on the risk mitigation offered by the use conditions proposed,
including requiring compliance with the third edition of UL Standard
60335-2-40, except to the extent the proposed rule conflicts with the
UL Standard, in which case we propose that the conditions specified in
the proposed rule would apply if finalized. We also request comment on
whether other use conditions would offer needed risk mitigation for the
flammable refrigerants proposed. EPA requests comment on whether non-
residential dehumidifiers have been designed for the refrigerant
proposed, HFC-32, any information on the safety of such equipment in
other countries, and if and how such experience would translate to safe
use in the United States. EPA also requests

comment on our description of different types of dehumidifiers and how
EPA classifies different types in different end-uses.

D. Residential and Light Commercial AC and Heat Pumps (HPs)--Proposed
Revision of Use Conditions Provided in the Previous Listing of HFC-32
as Acceptable, Subject to Use Conditions, for Use in New Self-Contained
Room ACs and HPs

    EPA previously listed HFC-32 as acceptable, subject to use
conditions, in new self-contained room ACs and HPs in SNAP Rule 19 (80
FR 19461; April 10, 2015). Today we are proposing to update those use
conditions to be consistent with use conditions applied to other
refrigerants with lower flammability as finalized in SNAP Rule 23 (86
FR 24444; May 6, 2021). The proposed use conditions would be required
on all such equipment manufactured on or after the effective date of
the final rule and would not apply to or affect equipment manufactured
before the effective date of the final action and manufactured in
compliance with the SNAP requirements applicable at the time of
manufacture.
1. Background on Self-Contained Room ACs and HPs
    EPA provided an overview of the residential and light commercial AC
and HPs end-use, and the self-contained equipment category within that
end-use, in SNAP Rule 19 (80 FR 19461; April 10, 2015) and the Notice
of Proposed Rulemaking for SNAP Rule 23 (85 FR 35881-35882; June 12,
2020). We believe the descriptions there adequately describe the end-
use category as it exists today.
2. What are the ASHRAE classifications for refrigerant flammability?
    See section II.A.2 above for further discussion on ASHRAE
classifications.
3. What is HFC-32 and how does it compare to other refrigerants in the
same end-use?
    See section II.A.3 above for further discussion on the
environmental, flammability, toxicity and exposure information for HFC-
32.
    A redacted submission and supporting documentation for HFC-32 are
provided in the docket for this proposed rule (EPA-HQ-OAR-2021-0836) at
https://www.regulations.gov. EPA performed an assessment to examine the
health and environmental risks of this substitute, available in the
docket for this proposed rule.\29\
---------------------------------------------------------------------------

    \29\ ICF, 2022n. Risk Screen on Substitutes in Residential and
Light Commercial Air Conditioning and Heat Pumps (New Equipment)
Substitute: HFC-32 (Difluoromethane).
---------------------------------------------------------------------------

    Comparison to other substitutes in this end-use: HFC-32 has an ODP
of zero, the same as other acceptable substitutes in this end-use, such
as R-290, HFC-134a, R-410A, and R-513A, with ODPs of zero.
    HFC-32 has a GWP of 675, higher than some of the acceptable
substitutes for residential and light commercial air conditioning and
heat pumps, including ammonia absorption, R-290, and R-454B with GWPs
of zero, three, and about 470, respectively. HFC-32's GWP is lower than
some of the acceptable substitutes for residential and light commercial
air conditioning and heat pumps, such as R-452B, HFC-134a, and R-410A,
with GWPs of approximately 700, 1,430, and 2,090, respectively.
    Information on the toxicity and flammability risk of HFC-32 in this
end-use category was provided in SNAP Rule 19. In summary, EPA found
the toxicity risks of HFC-32 to be comparable to or lower than other
acceptable alternatives. Although we noted that the flammability risk
of HFC-32 may be greater than that of other available, nonflammable
substitutes in the same end-use, we found that those risks are not
significant even under worst-case assumptions. These risks of HFC-32
are similar to the risks of other flammable refrigerants found
acceptable for this end-use category in SNAP Rule 23 (i.e., R-452B, R-
454A, R-454B, R-454C, and R-457A). We noted there that this risk can be
minimized by use consistent with industry standards such as UL 60335-2-
40--which would be required by our proposed revision to the use
conditions--and other industry standards, such as ASHRAE 15, as well as
recommendations in the manufacturers' SDS and other safety precautions
common in the refrigeration and air conditioning industry. The updates
to the use conditions proposed maintain the low potential risk
associated with the flammability of this alternative so that it will
not pose significantly greater risk than other acceptable substitutes
in this end-use category.
4. What use conditions currently apply to this refrigerant in this end-
use category?
    EPA previously found HFC-32 acceptable, subject to use conditions,
in new residential and light commercial AC for self-contained room AC
units, including packaged terminal air conditioner (PTAC) units,
packaged terminal heat pumps (PTHPs), window AC and HP units, and
portable AC units, designed for use in a single room in SNAP Rule 19
(80 FR 19454; April 10, 2015). Those requirements are codified in
appendix R of 40 CFR part 82, subpart G. EPA provided information on
the environmental and health properties of HFC-32 and the various
substitutes available at that time for use in this end-use.
Additionally, EPA's risk screen for this refrigerant is available in
the docket for this previous rulemaking (EPA-HQ-OAR-2013-0748).
    HFC-32 has an ASHRAE classification of A2L, indicating that it has
low toxicity and lower flammability. The flammability risks are of
potential concern because residential ACs and HPs traditionally used
refrigerants that are not flammable. In the presence of an ignition
source (e.g., static electricity, a spark resulting from a closing
door, or a cigarette), an explosion or a fire could occur if the
concentration of HFC-32 were to exceed the LFL of 144,000 ppm by
volume.
    To address flammability, EPA listed HFC-32 as acceptable, subject
to use conditions, in new self-contained room AC units. The current use
conditions address safe use of this flammable refrigerant and include
incorporation by reference of Supplement SA to the 8th edition (August
2, 2012) of UL Standard 484, refrigerant charge size limits based on
cooling capacity and type of equipment, and requirements for markings
and warning labels on equipment using the refrigerant to inform
consumers and technicians of potential flammability hazards. Without
appropriate use conditions, the flammability risk posed by this
refrigerant could be higher than non-flammable refrigerants because
individuals may not be aware that their actions could potentially cause
a fire, and because the refrigerant could be used in existing equipment
that has not been designed specifically to minimize flammability risks.
Our assessment and listing decisions in SNAP Rule 19 (80 FR 19454;
April 10, 2015) found that with the use conditions, the overall risk of
this substitute, including the risk due to flammability, does not
present significantly greater risk in the end-use than other
substitutes that are currently or potentially available for that same
end-use.
5. What updates to the use conditions is EPA proposing?
    EPA is proposing to update the use conditions that apply to HFC-32
in new self-contained room ACs and HPs for

equipment manufactured after the effective date of a final rule based
on this proposal. Several of the updated use conditions proposed for
self-contained room ACs and HPs are common to those proposed for other
end-uses in sections II.A, II.B, and II.C above. Because of this
similarity, EPA discusses the use conditions that would apply to all
four end-uses in section II.E. For HFC-32 in self-contained room ACs
and HPs, these are the only use conditions EPA is proposing. In
summary, with the updates proposed, the use conditions proposed are the
following:
    (1) New equipment only--This refrigerant may only be used in new
equipment designed specifically and clearly identified for the
refrigerant, i.e., this substitute may not be used as a conversion or
``retrofit'' refrigerant for existing equipment. This use condition is
the same as what currently exists for HFC-32 in this end-use category.
    (2) UL Standard--This refrigerant (i.e., in this case, HFC-32) may
be used only in equipment (i.e., in this case, self-contained room ACs
and HPs) that meet all requirements listed in the 3rd edition, dated
November 1, 2019, of Underwriters Laboratories (UL) Standard 60335-2-
40, ``Household and Similar Electrical Appliances--Safety--Part 2-40:
Particular Requirements for Electrical Heat Pumps, Air Conditioners and
Dehumidifiers'' (UL Standard). If this rule is finalized as proposed,
in cases where the final rule would include requirements different than
those of the 3rd edition of UL Standard 60335-2-40, EPA is proposing
that the appliance would need to meet the requirements of the final
rule in place of the requirements in the UL Standard. See section II.E
below for further discussion on the requirements of this standard that
EPA is proposing to incorporate by reference. This change in the use
condition updates the standard to which the equipment must comply from
Supplement SA to the 8th edition, dated August 2, 2012, of UL Standard
484, ``Room Air Conditioners'' to the 3rd edition of UL 60335-2-40.
    (3) Warning labels--Several warning labels are proposed as use
conditions as detailed in section II.E below. These labels are similar
or verbatim in language to those required by the UL Standard. The
warning labels must be provided in letters no less than 6.4 mm (\1/4\
inch) high and must be permanent. While the font size is the same as in
the use conditions that currently apply, several revisions to the
labels and the language in them have changed and are based on the
updated UL Standard, the 3rd edition of UL 60335-2-40.
    (4) Markings--Equipment must have distinguishing red (PMS #185 or
RAL 3020) color-coded hoses and piping to indicate use of a flammable
refrigerant. The equipment shall have marked service ports, pipes,
hoses and other devices through which the refrigerant is serviced.
Markings shall extend at least 1 inch (25mm) from the servicing port
and shall be replaced if removed. This use condition is the same as
what currently exists for HFC-32 in this end-use category.
    The regulatory text of the proposed decisions appears in tables at
the end of this document. If finalized as proposed, this text would be
codified by amending appendix R. The amendment would be to indicate
that the use conditions finalized apply to HFC-32 self-contained room
AC units manufactured on or after the effective date of such a final
rule (which we anticipate would be 30 days after publication in the
Federal Register). Equipment manufactured before the effective date of
the final rule would not be affected by this action and would hence be
subject to the use conditions included in appendix R at the time they
were manufactured. The proposed revisions to the current regulatory
text update the use conditions as they apply to the previous listing
decision for HFC-32 in self-contained room ACs and HPs. EPA notes that
there may be other legal obligations pertaining to the manufacture,
use, handling, and disposal of the proposed refrigerants that are not
included in the information listed in the tables (e.g., the CAA section
608(c)(2) prohibition on knowingly venting or otherwise knowingly
releasing or disposing of substitute refrigerants in the course of
maintaining, servicing, repairing or disposing of an appliance or
industrial process refrigeration, or Department of Transportation
requirements for transport of flammable gases). Flammable refrigerants
being recovered or otherwise disposed of from residential and light AC
appliances are likely to be hazardous waste under RCRA (see 40 CFR
parts 260-270).
6. How do the proposed use conditions differ from the existing ones and
why is EPA proposing to change the use conditions?
    The updated use conditions EPA is proposing are similar to the ones
that exist today in appendix R of 40 CFR part 82, subpart G for HFC-32
in this end-use category. The proposed requirements that HFC-32 must be
used in new equipment only and must include red markings at service
ports are repeated in this proposed listing. Existing room ACs using
HFC-32 manufactured before the effective date of a final rule to this
proposal would not be affected by these updated use conditions.
    Warning labels are required under EPA's current regulations, and
EPA is proposing to continue to require them, although with some
specific language changes. The warning labels EPA is proposing are
identical to those required as use conditions for the use of HFC-32 in
residential and light commercial AC and HPs (excluding self-contained
room ACs and HPs) and for R-452B, R-454A, R-454B, R-454C, and R-457A in
residential and light commercial AC and HPs (including self-contained
room ACs and HPs). EPA finds that using a common set of labels, similar
to those from UL Standard 60335-2-40, will aid in compliance especially
for a manufacturer that uses more than one of these refrigerants or
produces both self-contained room ACs and HPs and other types of
residential and light commercial AC and HPs. The updated labels EPA is
proposing use the opening word ``WARNING'' in lieu of ``DANGER'' or
``CAUTION'' and change ``Risk of Fire or Explosion'' to just ``Risk of
Fire.'' EPA is proposing that the labels must be provided in letters no
less than 6.4 millimeter (\1/4\ inch) high and must be permanent, which
is identical to the current requirement for HFC-32 in self-contained
room ACs and HPs.
    EPA is proposing to update the standard incorporated by reference
in the use conditions, replacing the requirement to follow certain
sections of the 2012 version of UL 484 with the proposed requirement to
adhere to the 3rd edition of UL Standard 60335-2-40. UL Standard 60335-
2-40 was developed in an open and consensus-based approach, with the
assistance of experts in the refrigeration and AC industry as well as
experts involved in assessing the safety of products. The revision
cycle for the 3rd edition, including final recirculation, concluded
with its publication on November 1, 2019. The 2019 UL Standard replaces
the previously published version of several standards, including UL
Standard 484, which had already been revised into a ninth edition by
that time. EPA was aware of the continuing progress of UL Standards to
address flammable refrigerants more appropriately. In the 2021 SNAP
Rule (SNAP Rule 23) listing HFC-32 for other categories within the
residential and light commercial AC and HPs end-use, we stated, ``EPA
understands that the standard we relied on in [SNAP] Rule 19 might
`sunset' in the future.

Therefore, we will continue to evaluate the market for the equipment
addressed in that rule, including HFC-32 in self-contained room ACs,
and whether to establish new or revised use conditions that reference
UL 60335-2-40'' (86 FR 24463; May 6, 2021). Today, we are proposing
such a change knowing that UL is replacing the standard to which such
equipment is certified from UL 484 to the newer UL 60335-2-40 standard.
    Updating the UL Standard incorporated as a use condition will
provide more consistency amongst the products within this end-use and
between HFC-32 and the five A2L refrigerants listed as acceptable,
subject to use conditions, for this end-use including self-contained
room ACs and HPs in SNAP Rule 23. This change will allow the industry
to focus on the existing standard. The change will be helpful in
implementing any transitions needed or planned for manufacturers,
installers, and technicians. A manufacturer, who may offer different
products within this end-use with different refrigerants, could use
similar processes, such as in developing and applying the warning
labels required. Installers and technician, likewise, would not need to
reference different standards depending on the type of equipment and
the particular A2L refrigerant being used in that equipment, when
putting in a new piece of equipment or servicing that equipment.
    Another revision to the use conditions is charge sizes. In the 2019
SNAP Rule, charge sizes from both UL 484 (8th edition) and those
stipulated by tables within the rule needed to be followed. Rather than
requiring examination of both items and determining which charge size
was lower, the proposed updated use conditions would rely on a single
document, the 3rd edition of UL Standard 60335-2-40.
7. What is the acceptability status of HFC-32 in self-contained room
ACs and HPs?
    If finalized as proposed, the use conditions in this action would
apply to new self-contained room ACs and HPs using HFC-32 manufactured
on or after the effective date of the final rule (which we anticipate
would be 30 days after publication in the Federal Register). The final
rule would not apply to or affect equipment manufactured before the
effective date of this action and manufactured in compliance with the
SNAP requirements applicable at the time of manufacture as stipulated
in SNAP Rule 19 and appendix R of 40 CFR part 82, subpart G at that
time. EPA views equipment to be manufactured at the date upon which the
appliance's refrigerant circuit is complete, the appliance can
function, the appliance holds a full refrigerant charge, and the
appliance is ready for use for its intended purposes. For self-
contained room ACs and HPs, this occurs at the factory. If this rule is
finalized as proposed, products manufactured between May 11, 2015, and
the effective date of the final rule would be required to meet the use
conditions in SNAP Rule 19 (which took effect May 11, 2015) and as
listed in appendix R of 40 CFR part 82, subpart G. Such products would
be permitted to be warehoused and sold through normal channels, even if
they are sold or installed after the effective date of the final rule
based on this proposed rule. Self-contained room ACs and HPs using HFC-
32 manufactured on or after the effective date of the final rule based
on this proposed rule would be required to meet the use conditions so
finalized and listed in the revisions to appendix R.
8. What additional information is EPA including in these proposed
listings?
    EPA is providing additional information related to these proposed
listings. Since this additional information is not part of the
regulatory decision under SNAP, these statements are not binding for
use of the substitute under the SNAP program. See section II.E.2 below
for further discussion on what additional information EPA is including
in these proposed listings. EPA notes that the additional information
is similar to, but not identical with, the addition information in the
listing for HFC-32 in self-contained room ACs and HPs in SNAP Rule 19.
EPA is proposing additional information consistent with that included
in the other proposed listings for air conditioning equipment in this
rule and consistent with that included in the listings for four A2L
refrigerant blends listed as acceptable subject to use conditions in
self-contained room ACs and HPs in SNAP Rule 23. 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.
9. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed updates to
the use conditions as discussed in section II.D above. EPA requests
comments on the proposed change in use conditions and if and how such
change would affect the safety of self-contained room ACs and HPs using
HFC-32.

E. Use Conditions and Further Information for Chillers, Residential
Dehumidifiers, Non-Residential Dehumidifiers, and HFC-32 Self-Contained
Room ACs and HPs

1. What use conditions is EPA proposing and why?
    As described above, EPA is proposing to list:

 HFO-1234yf, R-454A, R-454B and R-454C as acceptable, subject
to use conditions, for use in centrifugal and positive displacement
chillers for new equipment in comfort cooling applications, including
commercial AC and industrial process AC
 HFC-32 and R-452B as acceptable, subject to use conditions,
for use in scroll and rotary chillers for new equipment in comfort
cooling applications, including commercial AC and industrial process AC
 HFO-1234yf, HFC-32, R-452B, R-454A, R-454B, and R-454C as
acceptable, subject to use conditions, for use in residential
dehumidifiers for new equipment
 HFC-32 as acceptable, subject to use conditions, for use in
non-residential dehumidifiers for new equipment

    In addition, EPA is proposing to update the use conditions that
apply to the previous listing of:
     HFC-32 as acceptable, subject to use conditions, for use
in self-contained room ACs and HPs for new equipment.
    These use conditions are summarized in the listings under
subheadings II.A, II.B, and II.C, and the revisions to the use
conditions are summarized under subheading II.D, above, and are
explained here in greater detail. The use conditions EPA proposes
(either as new listings or revisions to a previous listing) include
conditions requiring use of each refrigerant in new equipment, which
can be specifically designed for the refrigerant; use consistent with
the UL 60335-2-40 industry standard, 3rd Edition, including testing,
charge sizes, ventilation, usage space requirements, and certain hazard
warnings and markings; and requirements for warning labels and markings
on equipment to inform consumers and technicians of potential
flammability hazards. The listings with specific use conditions are
intended to allow for the use of these lower flammability refrigerants
in a manner that will ensure they do not pose a greater overall risk to
human health and the environment than other substitutes in these end-
uses.

New Equipment Only; Not Intended for Use as a Retrofit Alternative
    EPA is proposing that these refrigerants may be used only in new
equipment which has been designed to address concerns unique to
flammable refrigerants--i.e., none of these substitutes may be used as
a conversion or ``retrofit'' refrigerant for existing equipment. EPA is
unaware of information on how to address hazards if these flammable
refrigerants were to be used in equipment that was designed for non-
flammable refrigerants. Given the flammable nature of these
refrigerants, the fact that EPA is unaware of information to assess the
risk if such retrofits were allowed, and because the refrigerants were
not submitted to the SNAP program for retrofits, EPA has not reviewed
them for retrofit applications for this proposal and is only proposing
that they may be used in new equipment which can be properly designed
for their use. This proposed use condition would not affect the ability
to service a system using one of these refrigerants once installed,
including the adding of refrigerant or replacing components.
Standards
    EPA is proposing that the flammable refrigerants may be used only
in equipment that meets all requirements in UL Standard 60335-2-40, 3rd
Edition.
    Those participating in the UL 60335-2-40 consensus standards
process (hereafter ``UL'') have tested equipment for flammability risk
and evaluated the relevant scientific studies. Further, UL has
developed safety standards including requirements for construction and
system design, for markings, and for performance tests concerning
refrigerant leakage, ignition of switching components, surface
temperature of parts, and component strength after being scratched.
Certain aspects of system construction and design, including charge
size, ventilation, and installation space, and greater detail on
markings, are discussed further below in this section. The UL 60335-2-
40 Standard was developed in an open and consensus-based approach, with
the assistance of experts in the AC 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 specific UL standards
that are most applicable and recognized by the U.S. market. This
approach is the same as that in our previous rules on flammable
refrigerants (e.g., 76 FR 78832; December 20, 2011 and 80 FR 19454;
April 10, 2015 and 86 FR 24444; May 6, 2021).
    A summary of the requirements of UL 60335-2-40 as they affect the
refrigerants and end-use addressed in this section of our proposal
follows. This summary is offered for information only and does not
provide a complete review of the requirements in this standard.
    Among the provisions in UL 60335-2-40 are limits on the amount of
refrigerant allowed in each type of appliance based on several factors
explained in that standard. The requirements in UL 60335-2-40 would
reduce the risk to workers and consumers. Annex GG of the standard
provides the charge limits, ventilation requirements and requirements
for secondary circuits. The standard specifies requirements for
installation space of an appliance (i.e., room floor area) and/or
ventilation or other requirements that are determined according to the
refrigerant charge used in the appliance, the installation location and
the type of ventilation of the location or of the appliance. Within
Annex GG, Table GG.1 provides guidance on how to apply the requirements
to allow for safe use of flammable refrigerants. UL 60335-2-40, 3rd
Edition contains provisions for safety mitigation. These mitigation
requirements were developed to ensure the safe use of flammable
refrigerants over a range of appliances. In general, as larger charge
sizes are used, more stringent mitigation requirements are required. In
certain applications refrigerant detection systems (as described in
Annex LL, Refrigerant detection systems for A2L refrigerants) and
refrigerant sensors (as described in Annex MM, Refrigerant sensor
location confirmation tests) such as safety alarms are required. Where
air circulation (i.e., fans) is required in accordance with Annex GG or
Annex 101.DVG, it must be initiated by a separate refrigerant detection
system either as part of the appliance or installed separately. In a
room with no mechanical ventilation, Annex GG provides requirements for
openings to rooms based on several factors, including the charge size
and the room area. The minimum opening is intended to be sufficient so
that natural ventilation would reduce the risk of using a flammable
refrigerant. The standard also includes specific requirements covering
construction, instruction manuals, allowable charge sizes, mechanical
ventilation, safety alarms, and shut off valves for A2L refrigerants.
    In addition to Annex GG and Table GG.1 mentioned above, UL 60335-2-
40 has a requirement for the maximum charge for an appliance using an
A2L refrigerant. Additional requirements exist for charge sizes
exceeding three times the LFL.
    Table GG.1 of the UL standard indicates that systems with
refrigerant charges exceeding certain amounts are outside the scope of
the standard, stating that ``National standards apply.'' Specifically,
if the refrigeration circuit with the greatest mass of a flammable
refrigerant is more than 260 times the lower flammability limit (in kg/
m\3\), such equipment is outside the scope. For example, HFC-32 has an
LFL of approximately 0.307 kg/m\3\ (0.0192 lb/ft\3\); therefore,
equipment with charge sizes of a single circuit exceeding 79.82 kg
(176.0 lb) would fall outside the scope of the UL Standard. EPA expects
that many chillers could exceed these charge thresholds and therefore
is proposing that an additional safety standard would apply for all
chillers, as discussed in section II.A above. EPA does not expect this
situation to occur for residential dehumidifiers or self-contained room
ACs and HPs because of their smaller charge sizes.
    EPA recognizes that this standard is undergoing revision. UL opened
for comment a proposed 4th edition of this standard as an update to the
3rd Edition to which comments were due March 1, 2022. UL standards are
open for public comment and participation following ANSI requirements.
Warning Labels
    As a use condition or revision to existing use conditions, EPA is
proposing to require labeling of chillers, residential dehumidifiers,
non-residential dehumidifiers, and HFC-32 self-contained room ACs and
HPs (``equipment'') containing the proposed flammable refrigerants. EPA
is proposing that the following markings, or the equivalent, must be
provided in letters no less than 6.4 mm (\1/4\ inch) high and must be
permanent:

i. On the outside of the equipment: ``WARNING--Risk of Fire. Flammable
Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do
Not Puncture Refrigerant Tubing''
ii. On the outside of the equipment: ``WARNING--Risk of Fire. Dispose
of Properly In Accordance With Federal Or Local Regulations. Flammable
Refrigerant Used''
iii. On the inside of the equipment near the compressor: ``WARNING--
Risk of Fire. Flammable Refrigerant Used. Consult Repair Manual/Owner's
Guide Before Attempting to Service

This Product. All Safety Precautions Must Be Followed''
iv. For any equipment pre-charged at the factory, on the equipment
packaging or on the outside of the equipment: ``WARNING--Risk of Fire
due to Flammable Refrigerant Used. Follow Handling Instructions
Carefully in Compliance with National Regulations''
1. If the equipment is delivered packaged, this label shall be applied
on the packaging
2. If the equipment is not delivered packaged, this label shall be
applied on the outside of the appliance

    EPA expects that all residential dehumidifiers and non-residential
dehumidifiers and all self-contained room ACs and HPs would be
packaged, and hence this label would be placed as stipulated in item 1
above. EPA expects that chillers could be provided packaged or not, and
this label would be placed as stipulated in item 1 or 2, respectively.

v. On the equipment near the nameplate:
1. At the top of the marking: ``Minimum installation height, X m (W
ft)''. This marking is only required if the similar marking is required
by the 3rd edition of UL 60335-2-40. The terms ``X'' and ``W'' shall be
replaced by the numeric height as calculated per the UL Standard. Note
that the formatting here is slightly different than the UL Standard;
specifically, the height in Inch-Pound units is placed in parentheses
and the word ``and'' has been replaced by the opening parenthesis.
2. Immediately below v.1. above or at the top of the marking if v.1. is
not required: ``Minimum room area (operating or storage), Y m\2\ (Z
ft\2\)''. The terms ``Y'' and ``Z'' shall be replaced by the numeric
area as calculated per the UL Standard. Note that the formatting here
is slightly different than the UL Standard; specifically, the area in
Inch-Pound units is placed in parentheses and the word ``and'' has been
replaced by the opening parenthesis.
vi. For non-fixed equipment, including residential dehumidifiers, non-
residential dehumidifiers, and self-contained room ACs and HPs, on the
outside of the product: ``WARNING--Risk of Fire or Explosion--Store in
a well-ventilated room without continuously operating flames or other
potential ignition.'' EPA expects that this label would be required on
residential dehumidifiers, non-residential dehumidifiers, and HFC-32
self-contained room ACs (e.g., including portable ACs, window ACs,
PTACs and PTHPs).
vii. For fixed equipment that is ducted, including chillers, near the
nameplate: ``WARNING--Risk of Fire--Auxiliary devices which may be
ignition sources shall not be installed in the ductwork, other than
auxiliary devices listed for use with the specific appliance. See
instructions.'' EPA expects that residential dehumidifiers, non-
residential dehumidifiers, and self-contained ACs and HPs would not be
ducted, but that chillers used for comfort cooling could be.

    The text of the warning labels, above, is exactly the same as that
required in UL 60335-2-40, with the exception of the label identified
in v., which is similar to that in the UL Standard. The major
difference between this proposed requirement and the requirements in
Table 101.DVF.1 of UL 60335-2-40 is that the markings for A2L
refrigerants, including HFO-1234yf, HFC-32 and the four refrigerant
blends, are required to be no less than 3.2 mm (\1/8\ inch) high in the
standard instead of 6.4 mm (\1/4\ inch) as EPA is proposing in this
action. EPA believes that it would be difficult to see warning labels
with the minimum lettering height requirement for A2L refrigerants of
\1/8\ inch in the UL Standard. Therefore, as in the requirements in our
previous flammable refrigerants rules (e.g., 76 FR 78832; December 20,
2011 and 80 FR 19454; April 10, 2015 and 86 FR 24444; May 6, 2021), EPA
is proposing that 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, first responders, and those disposing
the appliance to view the warning labels.
Markings
    Our understanding of the UL Standard is that red markings, similar
to those EPA has applied as use conditions in past actions for
flammable refrigerants (76 FR 78832; December 20, 2011 and 80 FR 19454;
April 10, 2015 and 86 FR 24444; May 6, 2021), are required by the UL
Standard for A2 and A3 refrigerants but not A2L refrigerants. EPA is
proposing that such markings apply to these A2L refrigerants as well to
establish a common, familiar and standard means of identifying the use
of a flammable refrigerant.
    These red markings 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 AC and refrigeration industry currently uses red-colored
hoses and piping as means for identifying the use of a flammable
refrigerant based on previous SNAP listings. 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 in SNAP listings, color-coded
hoses or pipes must be used for ethane, HFC-32, R-452B, R-454A, R-454B,
R-454C, R-457A, isobutane, propane, and R-441A in certain types of
equipment where these are listed acceptable, subject to use conditions.
All such tubing must be colored red PMS #185 or RAL 3020 to match the
red band displayed on the container of flammable refrigerants AHRI
Guideline N, ``2017 Guideline for Assignment of Refrigerant Container
Colors.'' The intent of this aspect of the proposal is to provide
adequate notice for technicians and others that a flammable refrigerant
is being used within a particular piece of equipment or appliance.
Another goal is to provide adequate notification of the presence of
flammable refrigerants for personnel disposing of appliances containing
flammable refrigerants. As explained in a previous SNAP rule, one
mechanism to distinguish hoses and pipes is to add a colored plastic
sleeve or cap to the service tube. (80 FR 19465; April 10, 2015). Other
methods, such as a red-colored tape could be used. The colored plastic
sleeve, cap, or tape would have to be forcibly removed in order to
access the service tube and would have to be replaced if removed. 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, cap or tape would be
of the same red color (PMS #185 or RAL 3020) 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 dyeing the hose or
pipe.
    EPA is proposing the use of color-coded hoses or piping as a way
for technicians and others to recognize that a flammable refrigerant is
used in the equipment. This would be in addition to the proposed use of
warning labels discussed above. EPA believes having two such warning
methods is reasonable and consistent with other general industry
practices. This approach is the same as that adopted in our previous
rules on flammable refrigerants (e.g., 76 FR 78832; December 20, 2011
and 80 FR 19454; April 10, 2015 and 86 FR 24444; May 6, 2021).

2. What additional information is EPA including in these proposed
listings?
    For chillers, residential, dehumidifiers, non-residential
dehumidifiers, and self-contained room ACs and HPs, EPA is including
recommendations, found in the ``Further Information'' column of the
regulatory text at the end of this document, to protect personnel from
the risks of using flammable refrigerants. Similar to our previous
listings of flammable refrigerants, EPA is including information on the
OSHA requirements at 29 CFR part 1910, proper ventilation, personal
protective equipment, fire extinguishers, use of spark-proof tools and
equipment designed for flammable refrigerants, and training. Since this
additional information is not part of the regulatory decision under
SNAP, these statements are not binding for use of the substitute under
the SNAP program. 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.
3. On which topics is EPA specifically requesting comment?
    EPA is requesting comment on all aspects of the proposed use
conditions described above and the appropriateness for applying these
use conditions to the listings for chillers, residential dehumidifiers,
and non-residential dehumidifiers, and the revisions to the listing for
self-contained room ACs and HPs described in sections II.A, II.B, II.C,
and II.D, respectively.
    EPA is requesting comment on the applicability of UL Standard
60335-2-40, 3rd Edition, to chillers, including for which chillers and
under which applications the standard applies. We likewise are
requesting comment on the applicability of the UL Standard to
residential dehumidifiers, non-residential dehumidifiers, and self-
contained room ACs and HPs.
    With regard to UL Standard 60335-2-40, EPA is requesting comment on
the status of the standard, the modifications that are being or have
been incorporated in it, how those modifications would change the risk
associated with the use of these flammable refrigerants in these end-
uses, and the appropriateness of adopting as a use condition the
current (3rd) edition of this standard.
    EPA recognizes that this standard is undergoing revision. UL opened
for comment a proposed 4th edition of this standard as an update to the
3rd Edition to which comments were due March 1, 2022. UL standards are
open for public comment and participation following ANSI requirements.
If the final 4th edition is published before EPA takes final action on
today's proposed listings that would incorporate the 3rd edition by
reference, EPA may incorporate the 4th Edition by reference into those
listings in lieu of the 3rd Edition. In that situation, EPA anticipates
reopening or extending the public comment period to provide an
opportunity for public comment on incorporating the final 4th edition
by reference into those listings.
    EPA is also requesting comment on requiring labeling, the height of
the lettering, and the likelihood of labels remaining on a product
throughout the lifecycle of the product, including its disposal.

F. Very Low Temperature Refrigeration (VLTR)--Proposed Listing of R-
1150 as Acceptable, Subject to Use Conditions and Narrowed Use Limits,
for Use in VLTR End-Use

1. Background on VLTR
    The very low temperature refrigeration end-use includes a wide
range of equipment types. VLTR equipment is intended to maintain
temperatures considerably lower than for refrigeration of food (below -
62 [deg]C or -80 [deg]F). Examples of very low temperature
refrigeration equipment include medical freezers and freeze-dryers,
which generally require extremely reliable refrigeration cycles to
maintain low temperatures and must meet stringent technical standards.
In some cases, VLTR equipment may use a refrigeration system with two
stages, each with its own refrigerant loop. This allows a greater range
of temperatures and may reduce the overall refrigerant charge.
    For this notice of proposed rulemaking, only equipment designed to
reach temperatures lower than -80 [deg]C (-112 [deg]F) is addressed.
See sections II.E.6 and II.E.7 below for a discussion of the narrowed
use limits describing the reasoning for this temperature requirement.
Examples of equipment covered by this proposed rule in the VLTR end-use
include:
     Freeze dryers. This equipment typically includes a two-
stage system, with a VLTR stage being addressed by this proposed rule
and a warmer stage, usually classified as industrial process
refrigeration, not addressed in this proposed rule. The primary
application of this equipment is for freeze drying material in a
laboratory setting.
     Cold traps required to operate below -80 [deg]C or -112
[deg]F. This equipment is used during laboratory evaporation to
condense vapors to prevent them from entering and damaging the pump, or
leaking into the environment, ensuring a closed system within the
vacuum pump.
     Very low temperature freezers designed to reach
temperatures below -80 [deg]C or -112 [deg]F.
    Each of these types of laboratory equipment, including other VLTR
equipment not mentioned that fit within the narrowed use limits
proposed in section II.F.6, would be subject to the listing decision
under this rule for R-1150 if this decision were to become final as
proposed.
2. What is EPA's proposed listing decision for R-1150?
    EPA is proposing to list R-1150 as acceptable, subject to use
conditions and narrowed use limits, for use in VLTR equipment,
including freeze-dryers, cold traps, and laboratory freezers. This
proposed listing would apply to all types of VLTR equipment that meet
the requirements of the UL Standard 61010-2-011, 2nd Edition, and for
all applications of such equipment under EPA's proposed use conditions
and narrowed use limits.
3. What is R-1150 and how does it compare with other refrigerants in
the same end-use?
    R-1150, also known as ethene or ethylene (CAS Reg. No. 75-85-1), is
an unsaturated hydrocarbon (HC). It is a flammable refrigerant with the
ASHRAE safety classification A3. You may find a copy of the applicants'
submissions, with CBI redacted, providing the required health and
environmental information for this substitute in this end-use in Docket
EPA-HQ-OAR-2021-0836 at www.regulations.gov under the names
``Supporting Materials for Rule 25 Listing of R-1150 in Refrigeration
and Air Conditioning. SNAP Submission Received December 3, 2018'' and
``Supporting Materials for Rule 25 Listing of R-1150 in Refrigeration
and Air Conditioning. SNAP Submission Received January 21, 2021.'' EPA
performed an assessment to examine the health and environmental risks
of this substitute. This assessment is available in Docket EPA-HQ-OAR-
2021-0836: ``Risk Screen on Substitutes in Very Low Temperature
Refrigeration (New Equipment). Substitute: R-1150.'' \30\
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    \30\ ICF, 2022o. Risk Screen on Substitutes in Very Low
Temperature Refrigeration (New Equipment); Substitute: R-1150.
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    Environmental information: R-1150 has an ODP of zero and a GWP of
four.
    In addition to ODP and GWP, EPA evaluated potential impacts of R-
1150

and other HC refrigerants on local air quality. R-1150 is considered a
VOC and not excluded from EPA's regulatory definition of VOC (see 40
CFR 51.100(s)) addressing the development of SIPs to attain and
maintain the NAAQS. As described below, EPA estimates that potential
emissions of HCs do not have a significant impact on local air quality.
This includes R-1150 in VLTR, when used in the refrigeration and AC
sector as substitute refrigerants in end-uses consistent with their
listings under the SNAP program.\31\
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    \31\ ICF, 2014. Assessment of the Potential Impact of
Hydrocarbon Refrigerants on Ground Level Ozone Concentrations.
February, 2014.
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    In response to the increased market share of HCs, particularly in
VLTR applications, EPA conducted additional analysis of various
scenarios to consider the potential impacts on local air quality if HC
refrigerants were used in further applications.\32\ In particular, use
of R-1150 in very low temperature freezers, including VLTR equipment
with an industrial process refrigeration (IPR) stage using propylene,
and R-1150 in retail food refrigeration systems \33\ were investigated
for ground-level ozone effects. The analysis first considers highly
conservative modeling scenarios where a specific HC would be used
widely across all end-uses in the refrigeration and AC sector. Scenario