\54\ The TEAP 2018 Quadrennial Assessment Report includes
sections for each of the Technical Options Committees (TOC):
Flexible and Rigid Foams TOC, Halons TOC, Methyl Bromide TOC,
Medical and Chemicals TOC, and Refrigeration, Air Conditioning and
Heat Pumps TOC. Available at: https://ozone.unep.org/science/assessment/teap.
    \55\ In accordance with Article 6 of the Montreal Protocol,
every four years the parties request assessments from various
advisory bodies, including the TEAP's quadrennial assessment of the
sectors and subsectors covered by the petitions. Under Decision
XXVIII/2 the TEAP is also instructed to review HFC substitutes every
five years. The parties also routinely request reports considering
transitions and/or related topics (e.g., commercial fisheries,
energy efficiency for the refrigeration and air conditioning
sector).
    \56\ TEAP 2022 Progress Report (May 2022) and 2018 Quadrennial
Assessment Report. Available at: https://ozone.unep.org/science/assessment/teap.
    \57\ Volume 3: Decision XXXIII/5--Continued provision of
information on energy-efficient and low-global-warming-potential
technologies, Technological and Economic Assessment Panel, United
Nations Environment Programme (UNEP), May 2022. Available at:
https://ozone.unep.org/system/files/documents/TEAP-EETF-report-may-2022.pdf.
---------------------------------------------------------------------------

    EPA also considered materials developed by, or submitted to, State
and foreign governments that have requirements restricting the use of
HFCs. Many of these jurisdictions highlight available substitutes that
can be used in place of regulated substances in the sectors and
subsectors that are the subject of this rulemaking.
    This is not an exhaustive list of sources that EPA could use in the
future to consider the availability of substitutes; section VI.E.1 of
this preamble describes additional sources of information that the
Agency considers to be best available data. For future Agency actions
under the Technology Transitions program, EPA would likely again
consider information from these sources to assess availability of
substitutes but the Agency may augment or omit sources where
appropriate to be consistent with the Agency's interpretation of
subsection (i)(4)(A).
    EPA has identified substitutes \58\ for use in lieu of regulated
substances in

specific sectors or subsectors by reviewing information from several of
these sources, which the Agency considers to be best available data.
EPA compiled a non-exhaustive list of available substitutes that
informed the GWP limit or restriction. See American Innovation and
Manufacturing Act of 2020--Subsection (i)(4) Factors for Determination:
List of Substitutes, referred to in this preamble as the ``List of
Substitutes TSD.'' That TSD and list were developed after considering,
to the extent practicable, the subsection (i)(4)(B) subfactors, as
discussed below and in the other TSDs available in the docket.
Substitutes for regulated substances have been identified in this list
as available for the sectors and subsectors for which EPA is
establishing restrictions.
---------------------------------------------------------------------------

    \58\ Inclusion of a substitute, either in the preamble or the
docket, is for informative purposes only and is not intended as an
EPA endorsement or recommendation.
---------------------------------------------------------------------------

    We note, however, that EPA's identification of a substitute as
``available'' for use in a particular sector or subsector is not
intended as a determination that such substitute is already widely used
in that sector or subsector, or that the subfactors in subsection
(i)(4)(B) are fully realized as to that substitute (even if those
conditions are true in some cases). For example, as stated in the
proposed rule, some of the substitutes EPA lists as ``available'' for a
sector or subsector may not yet be available uniformly throughout the
United States or may not be already permissible under building codes in
every jurisdiction in the United States (see section VI.E.2.d of this
preamble). Instead, the Agency interprets ``available'' in subsection
(i)(4)(B) as permitting it to consider the progress and status of a
substitute's incorporation into a sector or subsector, particularly in
relation to establishing the compliance deadlines for each restriction.
The statute would serve little purpose if EPA were only permitted to
restrict regulated substances where the (i)(4)(B) subfactors (e.g.,
building codes, contractor training costs, commercial demand) were
already ``satisfied'' because substitutes were already completely
adopted by the sector or subsector. Instead, it is reasonable for the
Agency to consider a substitute to be available based on the
expectation that, by the compliance date established in a restriction,
many of the (i)(4)(B) subfactors could feasibly be met. We recognize
that forecasting availability based on the (i)(4)(B) subfactors by an
established compliance dates in the future is an exercise that
inherently requires some estimation and uncertainty; for example, it is
impossible to perfectly predict the outcome of SNAP evaluations that
have not yet occurred or the success or failure of equipment redesigns
and safety tests. In setting compliance dates for the restrictions
under subsection (i), EPA is exercising its judgment and applying best
available data regarding how far along a sector or subsector is in the
transition to lower-GWP substitutes to determine when those substitutes
will be sufficiently available to accommodate a variety of uses within
the sector or subsector.
    Comment: One commenter stated that, in general, EPA has not
adequately assessed available substitutes and the ability of these
substitutes to be utilized in certain end uses by the dates that have
been proposed. The commenter stated that it is not apparent from the
proposed rule or the information that is available in the docket that
EPA has adequately assessed each of the end uses in sufficient detail,
or whether information the Agency has relied on correctly indicates
that substitutes (as defined through GWP limitations) are technically
achievable and therefore available.
    Response: EPA disagrees that the Agency has not adequately assessed
available substitutes. The commenter did not explain, as a general
matter, what information relied upon by the Agency it believed to be
unreliable or insufficiently detailed. EPA has considered information
provided by the TEAP, which taps into global expertise from industry,
academia, and the public sector. EPA also looked to its own SNAP
program, which has evaluated more than 500 ODS alternatives, many of
which are also substitutes for HFCs. Moreover, these were not the only
sources of information that the Agency relied upon, and additional
supporting information is cited for each of the finalized restrictions.
a. Commercial Demands and Technological Achievability
    Two of the subfactors that subsection (i)(4)(B) directs EPA, to the
extent practicable, to take into account in its consideration of
availability of substitutes are commercial demands and technological
achievability. This section provides information on how the Agency
views each term on its own, their potential impact on availability of
substitutes, and their interconnectedness.
    EPA views commercial demands as interest from OEMs and system
owners to use substitutes in products for ultimate sale or
installation. An OEM's interest in using a substitute is tied to their
ability to meet consumer needs. As discussed previously, EPA considers
a submission under the SNAP program to be an indicator that a chemical
producer or formulator anticipates commercial demand for the submitted
alternative. Another method to determine commercial demands is to
assess what types of equipment in a sector or subsector are for sale
and what regulated substances or substitutes are being used. Another
means for assessing commercial demands is to review the information
companies provide including, but not limited to, planned releases of
products or equipment using substitutes. Likewise, use of products or
equipment using substitutes by system owners can demonstrate commercial
demands for that equipment.
    EPA views technological achievability as the ability for a
substitute to perform its intended function in a sector or subsector.
For example, technological achievability can be demonstrated through a
substitute's compliance with or listing by standard setting bodies such
as ASHRAE or Underwriters Laboratories (UL) or through testing and
demonstration labs and projects.
    EPA provides additional information in the TSD American Innovation
and Manufacturing Act of 2020--Subsection (i)(4) Factors for
Determination: Technological Achievability and Commercial Demands,
referred to in this preamble as the ``Commercial Demands and
Technological Achievability TSD''; this TSD supports the Agency's
consideration of the commercial demands and technological achievability
subfactors and is available in the docket. The Commercial Demands and
Technological Achievability TSD identifies products and systems using
substitutes that are commercially available (i.e., products for sale),
or where manufacturers indicate they soon will be available, by sector
and subsector. EPA views commercial availability of products and
systems using substitutes as an indication of both commercial demand
and technological achievability. In other words, a product or system
using an available substitute in a market means that the particular
substitute is technologically achievable and that there is a commercial
demand for that substitute.
    The Agency relied on a range of sources and considered where
products and systems are already available as well as where they are
expected to be available given their use in other countries and/or
manufacturer announcements. These sources include, but are not limited
to, publicly available data such as information on ENERGY STAR
products, company websites,

SNAP listings, news articles, market reports, and communication with
industry experts. EPA also considers information that was provided to
relevant States as informative when evaluating whether a technology is
achievable or in commercial demand for the purposes of evaluating
available substitutes in their respective rulemakings. Another source
for considering technological achievability and commercial demand is
the information provided by petitioners. While EPA made every effort to
gather information related to these subfactors, we recognize that given
the scope of this rulemaking and the number of sectors and subsectors
covered, we may not have considered all versions and models of all
products or equipment in every sector or subsector.
    EPA is not limiting its consideration of commercial demands and
technological achievability to a specific geographic region since
products or systems may be introduced in a few markets first. The
information provided in this rule and the Commercial Demands and
Technological Achievability TSD available in the docket are based on
the best available data and were considered to the extent practicable
in this rulemaking.
b. Consumer Costs and Affordability for Residential and Small Business
Consumers
    Subsection (i)(4)(B) directs EPA, to the extent practicable, to
take into account consumer costs and affordability for residential and
small business consumers, among other subfactors, in its consideration
of availability of substitutes. EPA views these two subfactors as
related, in many instances, because residential and small business
consumers are a subset of consumers at large. The Act does not specify
in what way EPA should consider costs and affordability to these
consumers in determining whether a substitute is available. The
Agency's view is that the appropriate way to analyze consumer costs and
affordability is to look not at the total cost of a product/system
using a substitute, but rather at the difference in cost of a product/
system resulting from the transition. For this rule, the Agency has
considered the impact of its restrictions on the use of substitutes in
certain subsectors to the costs of products or systems for consumers of
all types. In some cases, EPA has extended proposed compliance dates to
mitigate potential cost impacts to consumers, because in doing so, the
Agency is anticipating that by the later compliance date established in
the final rule, the HFC phasedown required under subsection (e) will be
further along, there will be increased production of HFC substitutes,
and the cost of the substitute will be less of a barrier to the
availability of that substitute.
    Although some substitutes are more costly than HFCs today, the
experience with the ODS phaseout has been that prices of substitutes
generally decline as production increases, as more producers negotiate
licensing agreements for certain chemicals, and as patents expire. EPA
has compiled a memo in the docket which provides a non-exhaustive list
of several announcements that have been made regarding the initiation
or updating of production plants for various substitutes.\59\
Simultaneously, experience with the ODS phaseout and reductions in
supply of HFCs in other parts of the world, suggest that the price of
HFCs will increase as a result of the phasedown. While these are the
anticipated trends, EPA finds that the cost of using a regulated
substance or substitute generally represents only a small fraction of
the total cost of the product.\60\ For the RACHP sector, the cost of
refrigerant is less than one percent of the entire cost of the system,
and the highest costs come from raw materials such as copper, steel,
and aluminum that are used to make the equipment.\61\ Therefore, even a
large change in the cost of the refrigerant is unlikely to have a
significant impact on the overall cost of the product.
---------------------------------------------------------------------------

    \59\ See memo titled, Technical Support Company Announcements of
Increased Production of Low-GWP Substitutes in the docket that
presents company announcements of increased production of lower-GWP
substitutes. This memo is for informational purposes and does not
represent endorsement by the Agency. EPA further notes that this
memo is a non-exhaustive sampling of announcements; there may be
other companies announcing increased production of lower-GWP
substitutes.
    \60\ U.S. Department of Energy, Technical Support Document:
Energy Efficiency Program for Consumer Products: Residential Central
Air Conditioners and Heat Pumps, December 2016. Available at:
https://www.regulations.gov/document?D=EERE-2014-BT-STD-0048-0098.
    \61\ Consumer Cost Impacts of the U.S. Ratification of the
Kigali Amendment, JMS Consulting in partnership with INFORUM,
November 2018. Available in the docket.
---------------------------------------------------------------------------

    Additionally, substitutes are more efficient refrigerants than the
HFCs currently used, with some exceptions. This means that less
refrigerant is necessary in the finished product. More importantly,
this can reduce costs of the equipment because it requires less raw
material such as copper, steel, and aluminum to create heat transfer
elements. EPA applied the savings from using fewer raw materials and
improved energy efficiency only when EPA found sufficient literature
supporting such claims; however, other such cost saving factors may be
relevant to other subsectors.
    In considering affordability for residential and small business
consumers and consumer costs, the Agency has also looked at overall
compliance costs associated with this rule to OEMs, importers,
retailers, distributors, and other regulated entities. This is because
compliance costs to these entities tend to be passed on to consumers.
EPA has previously analyzed ``consumer costs'' in relation to
``compliance costs'' and found very little difference in these.\62\ EPA
included the cost to consumers in an analysis of the HFC phasedown as
stipulated in the AIM Act that Congress was considering in 2019. In
that analysis, the costs to consumers were approximately $0 to $200
million less than the compliance costs, depending on the compliance
step-down year (EPA analyzed 2020, 2024, 2029, and 2034). Compared to
the total cumulative costs or savings estimated, these differences
represented no more than a 20 percent difference, and in all cases were
decreases in total costs or increases in total savings.
---------------------------------------------------------------------------

    \62\ See ``American Innovation and Manufacturing Act of 2019:
Compliance and Consumer Cost Estimates'' document in the docket.
---------------------------------------------------------------------------

    EPA's estimates of compliance costs include energy efficiency
changes of equipment when switching from a regulated substance to a
substitute, where data were available. To the extent available, EPA's
analysis factored in energy efficiency changes inherent to the
substitute, which is separate from the energy efficiency gains from
using new equipment subject to more recent efficiency standards. These
costs (or savings) will likely impact all consumers of the equipment
using the substitutes, as the ones paying for the electricity. In this
case, the consumer could be a residential consumer or a small business
consumer, for instance a restaurant buying a new air conditioning unit
or a small convenience store using new stand-alone retail food
refrigeration equipment.
    EPA's Costs and Environmental Impacts TSD summarizes many of the
Agency's analytical results regarding the costs of using substitutes in
the impacted subsectors (which in turn informed the Agency's assessment
of whether that substitute is available) as well as the expected costs
and negative costs (i.e., savings) to industry associated with
transitioning from a regulated substance to a substitute. This
discussion (and the Costs and

Environmental Impacts TSD) refers to the cost of manufacturing,
purchasing, operating, and maintaining a product or system with a
substitute that complies with the restrictions compared with that same
product or system using a prohibited substance. For example, for the
residential and light commercial air conditioning and heat pump
subsector, the costs of manufacturing units that use lower-GWP
substances or blends (e.g., R-454B), and maintaining the operation of
that equipment, compared to those costs for a baseline unit (e.g., one
that uses R-410A including the operation and maintenance of that unit),
are used to generate an approximate accounting of the full cost (or
potential savings) of the transition. Depending on the substitute and
application, this can result in savings or costs borne by the consumer.
    Data to develop the cost estimates summarized in the Costs and
Environmental Impacts TSD were derived from a variety of information
sources including technical literature and experts. EPA provides
additional details regarding the data used in the RIA addendum and its
accompanying appendices and references cited. The cost factors were
applied to develop transition scenarios consistent with this rule using
EPA's Vintaging Model. The resulting costs and abatement were used in a
similar manner as the Marginal Abatement Cost analysis explained in the
Allocation Framework RIA.
    With respect to subsection (i)(4)(B)'s direction to consider
affordability for small business consumers in particular, the Agency
also analyzed whether its restrictions as a whole could have a
significant economic impact on a substantial number of small business
consumers. The analysis found that approximately 162 of the 51,047
potentially affected small businesses could incur costs in excess of 1
percent of annual sales and that approximately 110 small businesses
could incur costs in excess of 3 percent of annual sales. Based on this
analysis, we do not anticipate a broad, significant economic impact on
small businesses as a result of the final restrictions. We expect that
these results largely stem from the anticipated reduced costs of
substitute chemicals as compared with HFCs as well as potential energy
savings and reduced material costs for equipment as discussed above.
This rule also does not require any consumers to stop using and
maintaining their existing equipment.
    Equipment manufacturers, which are often small businesses, have
also already begun to transition to different refrigerants required by
this rule in response to regulations being implemented in several
States. Although State actions do not affect the entire U.S. market,
many manufacturers have begun the transition to HFC substitutes to have
products that can be sold nationally and comply with regulations in
export markets. Additional information on potential impacts of this
rule on small businesses can be found in the Small Business Regulatory
Enforcement Fairness Act (SBREFA) \63\ screening analysis located in
the docket for this rulemaking.
---------------------------------------------------------------------------

    \63\ Economic Impact Screening Analysis for Restrictions on the
Use of Hydrofluorocarbons under Subsection (i) of the American
Innovation and Manufacturing Act, available in the docket.
---------------------------------------------------------------------------

    One factor that affects affordability for residential and small
business consumers is up-front capital costs for new equipment.
Compared to large businesses, both groups may be less likely to be able
to afford high up-front capital costs. However, this rule does not
require that existing equipment be retired by a specific date, nor are
estimates of emission reductions associated with these restrictions
predicated on the assumption that equipment would be retired
prematurely. Indeed, this final rule makes substantial changes from the
proposed rule to reduce costs borne by distributors and equipment
owners associated with the sell-through of products, the repair of
existing systems, and the continued supply of components.
    More salient to EPA's analysis is consideration of the costs of a
substitute and its impacts on availability, particularly with regard to
investments that must be made in redesigning equipment to incorporate
use of the substitute. This redesign may have downstream costs on
consumers, both small business and residential. One way EPA has
factored in these costs and attempted to mitigate downstream impacts on
consumers is by establishing compliance dates that are further in the
future than the one-year required under the AIM Act. By signaling
earlier to regulated industry that transitions will be required and
providing more than one year for compliance, EPA provides some economic
and regulatory certainty to designers and manufacturers, and eases
supply constraints on components that these manufacturers may need for
the redesign. Additionally, staggering the compliance dates across
multiple years, rather than having a single January 1, 2025, compliance
date, lessens potential bottlenecks in the transition to manufacture
new equipment, such as testing and certification of equipment by a
nationally recognized testing laboratory (NRTL). The resultant savings
may then be passed on to consumers.
    Comment: One commenter stated that EPA failed to consider higher
repair and servicing costs over the life of these systems caused by the
proposed rule. The commenter asserted that by moving to flammable
refrigerants, service technicians must undertake additional precautions
that would add to the time and cost to repairs; that moving from one
refrigerant (R-410A) to multiple refrigerants will require costly
redundancy of refrigerant-specific servicing equipment; and that newly
designed equipment is generally less reliable and requires more repairs
than established products.
    Response: EPA disagrees with this commenter. In the context of
availability, EPA did consider repair and servicing. As explained
elsewhere in this final rule, this is not the first transition for most
of the sectors and subsectors covered by this rule. Many manufacturers
already use flammable HFCs or HFC alternatives including in foams,
aerosols, and RACHP. EPA understands that there may be additional
technician training needed; however, training is often needed when
alternatives are introduced including with regard to inherent
characteristics of the alternative that could include flammability,
glide, changes in compatibility with components or oils, and other
factors. Therefore, the need for training or changes in how repairs are
undertaken, for example, is not limited to the introduction of
flammable alternatives. We expect that under the HFC phasedown, access
to HFCs, both newly manufactured and reclaimed, will continue far into
the future, particularly given that the AIM Act directs EPA to phase
down and not to phase out HFC production and consumption and subsection
(h) provides direction concerning maximizing reclamation of HFCs. A
network of reclaimers offer reclaimed HFCs that can be used to service
existing equipment for its full useful life. Reclaimed CFCs and HCFCs
remain available in the United States for servicing equipment that was
designed, sold, installed, and continues to be operated by residential
and small business consumers. Furthermore, the Regulatory Impact
Analysis for this rule finds that for many subsectors, required
transitions will provide net savings to the economy over time, which
may in turn be passed on to small business and residential consumers.

c. Safety
    Subsection (i)(4)(B) directs EPA, to the extent practicable, to
take into account safety in its consideration of the availability of
substitutes. As part of EPA's consideration of safety, EPA is providing
additional information in the Safety TSD. This TSD supports the
Agency's consideration of the safety subfactor and is available in the
docket. EPA has reviewed information on flammability and toxicity as
well as the ability of substitutes to meet relevant industry safety
standards. In our interpretation of best available data, we evaluated
information from recognized industrial sources, including standard-
setting bodies, the SNAP program, international technical committees,
and information from petitions. Safety information may impact the
availability of substitutes in a particular sector or subsector, for
example, if there are restrictions on the use of a substance in local
building codes and/or regulatory requirements. Industry acceptance of
substitutes that are compliant with safety standards is also an
indication of safety and, therefore, impacts the use of a particular
substitute.
    Taking safety into account in considering the availability of
substitutes is not intended to limit substitutes to only those that are
risk free. This interpretation under subfactor (i)(4)(B) is informed by
the approach EPA has taken under the SNAP program, where the Agency has
likewise stated that it does not require alternatives to be risk free
(59 FR 13044, March 18, 1994). Many industry standards are designed to
mitigate risk and allow for the safe use of flammable, toxic, or high-
pressure substitutes. EPA therefore understands the direction to take
safety into account, to the extent practicable, as encompassing
consideration of information on the risks associated with the
substitute as well as information on risk mitigation.
    EPA has considered the listings under SNAP in its assessment of the
availability of substitutes in this rule. The SNAP program, in making
listing decisions for a substitute (e.g., to list as acceptable or
unacceptable), considers whether a substitute presents human health and
environmental risks that are lower than or comparable to such risks
from other substitutes that are currently or potentially available for
the same uses. Under this comparative risk evaluation, the human health
risks analyzed include safety, and in particular, flammability,
toxicity, exposure (of workers, consumers, and the general population)
to chemicals with direct toxicity; and exposure of the general
population to increased ground-level ozone. Under the SNAP program, EPA
makes decisions that are informed by its overall understanding of the
environmental and human health impacts.
    Under SNAP, EPA can list substitutes as ``acceptable subject to use
conditions,'' indicating that a substitute is acceptable only if used
in a certain way. Use conditions can include, but are not limited to,
warning labels, charge size limits, compliance with relevant safety
standards, unique fittings for servicing of equipment, and restrictions
on where a substitute is used (e.g., normally unoccupied spaces).
    EPA can also list substitutes as ``acceptable subject to narrowed
use limits'' under SNAP, indicating that a substitute may be used only
within certain specialized applications within an end-use and may not
be used for other applications within that end-use. EPA lists an
alternative as acceptable subject to narrowed use limits because of a
lack of available alternatives within the specialized application.
Users of an alternative in this category must make a reasonable effort
to ascertain that other alternatives are not technically feasible for
reasons of performance or safety. Users are expected to undertake a
thorough technical investigation of alternatives to the otherwise
restricted compound. Although users are not required to report the
results of their investigations to EPA, users must document these
results and retain them in their files for the purpose of demonstrating
compliance.
    EPA lists substitutes as ``unacceptable'' under SNAP if the Agency
determines that they may increase overall risk to human health and the
environment, compared to other alternatives that are available or
potentially available for the same use. EPA has listed substitutes as
unacceptable considering the human health criteria described above, as
well as the environmental factors considered under SNAP. For example,
SNAP has listed certain substitutes as unacceptable due to unusually
high ozone depletion potential, global warming potential, toxicity and
exposure, flammability (where it is not clear how to mitigate risks
sufficiently), and potential impacts on local air quality. Substitutes
listed as unacceptable in an end-use are prohibited for that use for
those subject to SNAP.
    EPA evaluates substitutes under the SNAP program on an ongoing
basis and over time has listed numerous substances as ``acceptable,''
``acceptable, subject to use conditions,'' or ``acceptable, subject to
narrowed use limits.'' Often, EPA applies compliance with relevant
safety standards, such as those discussed in the remainder of this
section, as a use condition to mitigate some of the risk associated
with using certain substitutes, particularly those that are classified
as flammable. Therefore, updates to standards can greatly affect how
SNAP considers the safe use of certain substitutes, and expanded risk
mitigation strategies required by standards could reduce the
comparative risk evaluation of a substitute under SNAP. The SNAP
program also often applies use conditions in addition to those required
by safety standards, which can further reduce the risk associated with
use of a substitute.
    In its evaluation of the safety subfactor under subsection
(i)(4)(B) for refrigerants, EPA is also considering the safety group
classification designated by ASHRAE Standard 34, and requirements for
the safe design, construction, installation, and operation of systems
under ASHRAE Standard 15, Safety Standard for Refrigeration Systems,
and 15.2, Safety Standard for Refrigeration Systems in Residential
Applications. ASHRAE Standard 34 assigns a designation consisting of
two to three alphanumeric characters (e.g., A2L or B1). The initial
capital letter indicates the toxicity, and the numeral and trailing
letter, if any, denotes the flammability. Under this standard, Class A
refrigerants are those 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. Refrigerants that are listed under the B (higher
toxicity) classification of ASHRAE Standard 34 have been used safely
and effectively for many years. For example, after the CFC phaseout,
several companies offered comfort cooling chillers using HCFC-123, and
at least one has since transitioned to the low-GWP B1 refrigerant R-
514A in part of its product line. These systems generally have low leak
rates, are located away from building occupants in limited-access areas
(e.g., mechanical rooms) with secured entrances, and utilize
refrigerant sensors and alarms to alert operators of leaks. Building
codes further reduce risks by requiring, for

example, mechanical ventilation to the outdoor space where such systems
are placed.
    The standard also assigns refrigerants a flammability
classification of 1, 2, 2L, or 3 based upon the results of standardized
testing for flame propagation, heat of combustion, lower-flammability
limit (LFL), and burning velocity. Tests for flammability are conducted
in accordance with American Society for Testing and Materials E681
using a spark ignition source at 140 [deg]F (60 [deg]C) and 14.7 psia
(101.3 kPa).\64\ The flammability classification ``1'' is given to
refrigerants that show no flame propagation. The flammability
classification ``2'' is given to refrigerants that exhibit flame
propagation, have a heat of combustion less than 19,000 kJ/kg (8,169
BTU/lb), and have a LFL greater than 0.10 kg/m\3\. The flammability
classification ``2L'' is given to refrigerants that 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 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.
---------------------------------------------------------------------------

    \64\ ASHRAE, 2022. ANSI/ASHRAE Standard 34-2022: 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.
Information on the ASHRAE classification of each substitute identified
by EPA for this rule is available in the docket for this rulemaking.
    ASHRAE Standard 15 specifies requirements for air-conditioning and
refrigeration systems 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 that 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. 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. 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
final rule 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.
    ASHRAE Standard 15 is generally followed for several of the RACHP
subsectors addressed in this rule, and in many cases is required as a
use condition under SNAP for comfort cooling chillers (see 88 FR 26382,
April 28, 2023) or adoption either by reference or through similar
language in local building codes. Therefore, part of our consideration
of safety in our evaluation of the availability of substitutes is based
on our knowledge of this and other ASHRAE Standards, and the evaluation
of safety in these standards regarding substances, equipment, and use
conditions. For example, the scope of ASHRAE standard 15 specifically
excludes refrigeration systems operating with R-717 (ammonia)
refrigerant and references IIAR Standard 2, American National Standard
for Safe Design of Closed-Circuit Ammonia Refrigeration Systems. For
subsectors where R-717 is currently widely employed (e.g., industrial
process refrigeration, cold storage warehouses, ice rinks) or where it
may be used as a substitute, our consideration of safety in evaluating
the availability of substitutes also incorporates this standard. Where
the standards distinguish what types of refrigerants may be used based
on a feature of the equipment (e.g., charge size), EPA has in some
instances considered those distinctions in setting the levels of
restrictions or the timing of compliance dates.
    EPA also considered UL standards in factoring in safety when
evaluating the availability of substitutes under subsection (i)(4)(B).
In general, UL standards provide engineering, labeling, and design
requirements that address potential safety concerns for various types
of refrigeration, air-conditioning, and heat pump equipment. Updates to
UL standards are then incorporated into other regulatory and industry
assessments, such as updates to SNAP listings, equipment design and
testing, and changes to building codes. In some cases, EPA took notice
of the timing of a publication of an update to a UL standard in
establishing the compliance date for a subsector restriction, such as
the safety standard UL 60335-2-89. This standard covers chillers used
for IPR and other IPR systems, cold storage warehouses, retail food
refrigeration equipment, and commercial ice machines. In October 2021,
the 2nd edition of the standard was published, updating safety
requirements so that flammable and lower flammability refrigerants
could be deployed more widely in commercial refrigeration equipment.
These updates included safety requirements, such as sensors in the room
to trigger refrigerant shut-off valves when a refrigerant leak is
detected and updated warning labels that better alert technicians,
equipment users, and firefighters that a flammable refrigerant is
contained in the equipment, among others. The updates included in UL
60335-2-89, 2nd edition, enable lower-GWP flammable refrigerants to be
used safely in equipment in greater amounts than before through
expanded mitigation strategies.
    Based on the above, we find that products and systems can be used
safely even if there are challenges with the HFC or HFC blend
substitute being used. For example, most products within the RACHP
sector will be tested at NRTL for conformance to the applicable UL
standard and other requirements (e.g., DOE energy conservation
standards, National Sanitation Foundation (NSF) requirements). This
testing provides a check on the products design to ensure, for
instance, that charge sizes of flammable refrigerants do not exceed the
standard's limit and that proper design and mitigation features are
included as required. Likewise, when building projects are permitted,
the authority having jurisdiction will typically review the design
including specification on the refrigeration systems and conduct
another review before giving permission for the building to commence
operation. This too provides a check on the safety of such systems, for
instance by ensuring compliance with ASHRAE Standard 15 or similar
requirements provided by the local building codes.
    Additional information on EPA's consideration of safety is
available in the Safety TSD in the docket.
d. Building Codes
    Subsection (i)(4)(B) directs EPA, to the extent practicable, to
take building codes into account in its consideration

of availability of substitutes. For certain types of equipment,
especially in the RACHP sector, building codes may inform which
substances can be used or may prescribe additional requirements before
a specific substance can be used, thereby impacting availability of
substitutes in some jurisdictions. This section summarizes EPA's
understanding of building code development across the nation generally
and how model building codes are developed and adopted into local
building codes. EPA has considered this information, to the extent
practicable, to evaluate how building codes may affect the availability
of substitutes to regulated substances. Additional information is found
in the TSD American Innovation and Manufacturing Act of 2020--
Subsection (i)(4) Factors for Determination: Building Codes, referred
to in this preamble as the ``Building Codes TSD.'' This TSD supports
the Agency's consideration of the building codes subfactor and is
available in the docket.
    Building codes are established at the subnational level and can
differ greatly across jurisdictions. Some States develop their own
building codes and determine the frequency with which they are updated.
Other states adopt (and sometimes amend) ``model'' building codes that
are written by code-setting organizations. Code-setting organizations
include the International Association of Plumbing and Mechanical
Officials (IAPMO), the International Code Council (ICC), and the
National Fire Protection Association (NFPA). Many States allow local
governments to set their own building codes, provided they comply with
the minimum standards established under State building codes. Both
State and local building codes are periodically reevaluated and
updated. The Agency did not review every jurisdiction's building codes
as EPA does not view that as practicable.
    Model building codes serve as the basis for many State and local
building codes and incorporate a range of industry standards that
establish specific requirements for building performance or design.
Several of these standards are directly relevant to the availability of
substitutes in the RACHP sector. EPA considered, to the extent
practicable, updates to industry standards and if those updates may be
incorporated into model building codes that will allow the future use
of products that use substitutes. EPA also considered whether current
building codes permit the installation and use of products and systems
using substitutes, particularly with respect to setting compliance
dates for restrictions. As noted earlier, EPA does not interpret
subsection (i)(4)(B)'s direction to factor in building codes, to the
extent practicable, as a requirement that EPA must find that current
building codes already permit the use of a substitute before it may be
deemed available.
    EPA understands that, in some cases, jurisdictions need to update
their building codes for some substitutes to be available for certain
uses. EPA finds it reasonable to consider that updates to building
codes may already be underway to reflect updated regulatory
requirements or safety standards, and for EPA to establish compliance
dates with the expectation that jurisdictions will prioritize
completing those updates with those deadlines in mind. EPA is aware of
ongoing efforts by industry groups and other stakeholders to work with
State and local officials to update building codes to allow for
alternative refrigerants. EPA has had and will continue to have
discussions concerning agency rulemaking and meet with relevant
stakeholders, including State officials. In some cases, it will be
EPA's establishment of a future restriction that will serve as the
catalyst, or at least a contributing factor, to the updating of
building codes to accommodate those restrictions. Users may also be
able to take other actions, usually site-specific, to show comparable
safety to existing refrigerants and systems to receive approval from
the authority having jurisdiction, even where building code updates are
not yet complete. The Agency has therefore, for many of the subsectors
addressed in this final action, provided additional time enabling those
jurisdictions to update their building codes or legislation
accordingly.
    Model codes are typically updated on a three-year cycle, and most
model building codes were last updated in 2021; the next scheduled
updates are for 2024. Several proposed changes in the current code
development cycle for the 2024 codes could enhance the availability of
HFC substitutes under model building codes. For example, ICC, an
international developer of model codes, standards, and building safety
solutions, approved changes to many model codes that affect the
availability of A2L refrigerants for the RACHP sector. These model code
changes, which will go into effect in 2024, are consistent with updated
industry standards that allow the use of substitutes identified in this
rulemaking. However, State and local building code agencies do not
automatically adopt updates to the model codes and thus, they may not
be implemented until after 2024.
    Information from stakeholders, including petitioners, indicates
that several States are updating building codes both as part of the
cyclical review and off cycle that would allow for the use of
additional HFC substitutes. For example, Oregon, California, and
Colorado have recently made, or are considering making, changes to
their codes that would effectively incorporate updated industry
standards as reflected in the model code changes that occurred in 2021.
Updated codes may require automatic refrigerant leak detection systems,
circulating fans, and labeling and handling instructions for flammable
refrigerants in certain applications and installations.
    Additional information on EPA's consideration of building codes can
be found in the Building Codes TSD in the docket.
e. Appliance Efficiency Standards
    As part of the Agency's consideration of the availability of
substitutes as directed by subsection (i)(4)(B), EPA is taking into
account, to the extent practicable, appliance efficiency standards. EPA
consulted with the U.S. Department of Energy regarding relevant minimum
energy efficiency standards and the timing for any planned changes to
the current standards. DOE, through its Building Technologies Office
and Appliance and Equipment Standards Program, sets minimum energy
efficiency standards for more than 60 different types of equipment,
including appliances and equipment used in homes, businesses, and
elsewhere.\65\ Several of these equipment types are within the RACHP
sector and are covered in this action. Among the equipment relevant to
this action are consumer products (e.g., refrigerators, freezers, and
room air conditioners) and commercial and industrial systems (e.g.,
automatic commercial ice machines, vending machines, walk-in coolers,
and walk-in freezers).\66\ EPA provides additional information in the
memo American Innovation and Manufacturing Act of 2020--Subsection
(i)(4) Factors for Determination: Appliance Efficiency Standards,
referred to in this preamble as the ``Appliance Efficiency Standards
memo.'' This memo supports the Agency's consideration of the appliance

efficiency standards subfactor and is available in the docket.
---------------------------------------------------------------------------

    \65\ See the U.S. Department of Energy's Appliance and Equipment
Standards Program available at: www.energy.gov/eere/buildings/appliance-and-equipment-standards-program.
    \66\ For additional information and a complete list of products,
please refer to the U.S. Department of Energy's website available
at: www.energy.gov/eere/buildings/standards-and-test-procedures.
---------------------------------------------------------------------------

    The DOE Appliance and Equipment Standards Program regularly
develops and updates appliance efficiency standards and test
procedures. Future revisions to existing appliance efficiency standards
could impact what substitutes are chosen to be used in equipment in
specific sectors and subsectors. EPA is in regular communication with
DOE so both agencies are aware of the schedules for these separate but
related actions. The Appliance Efficiency Standards memo lists
applicable standards in relevant sectors and subsectors and identifies
standards currently undergoing revision. We understand that for
redesign and testing of equipment, industry prefers that DOE and EPA
regulations are synchronized where possible. Given that DOE and EPA
operate under separate Congressional mandates, that synchronization may
not always be possible, but sharing information early can reduce
inconsistencies such that, to the extent possible, the refrigerants
used to set performance standards will be available under the
technology transitions program. For example, EPA discussed with DOE
test procedures that they developed for Automatic Commercial Ice
Machines (ACIMs). Based in part on that discussion, and as suggested in
comments, EPA is not finalizing the restrictions for this subsector as
proposed, but rather is finalizing restrictions in part by referencing
DOE regulations (see section VI.F.1.g). EPA also recognizes the
potential to greatly increase climate protection by both reducing the
GWP of substances used in the relevant subsectors (e.g., construction
foams, appliances foams, and refrigerants) covered by this action and
supporting energy efficiency in such applications.
    Comment: Commenters stated that product design changes for
refrigerant and efficiency both require a significant amount of time,
resources, and capital and that there is benefit to every stakeholder
in the channel if these regulatory actions are coordinated. One
commenter stated that new DOE efficiency standards for ACIMs will be
effective between 2027 and 2029 and the proposed compliance dates would
require redundant work to develop products that first comply with both
requirements. Two commenters that manufacture ice machines stated that
many of their products will become less efficient by up to 10 percent
due to the operating differences of the refrigerants.
    Response: EPA recognizes that other requirements such as DOE energy
conservation standards apply to ACIMs just as they apply to many RACHP
subsectors. While EPA and DOE operate under different authorities and
must follow timelines as set forth by these authorities, we find that
the compliance dates finalized here broadly meet the commenters'
request. For remote ACIMs, a compliance date of 2027, and for self-
contained ACIMs, compliance dates of 2026 or 2027 with a three-year
sell-through period, comport well with the commenter's prediction of
DOE efficiency standards becoming effective in 2027 to 2029. DOE has
already begun the process for such standards, and OEMs can choose to
develop new products meeting the restrictions set in this rule while at
the same time considering potential DOE energy conservation standards.
    EPA disagrees that ACIMs using alternative refrigerants will
necessarily experience a drop in efficiency. One ACIM manufacturer
recently reported on results of an ACIM after the R-404A compressor was
replaced with an R-290 one, finding a 34 percent energy savings and an
increase of 35 percent in ice production.\67\ DOE found a similar
improvement when using R-290 in a different type of ACIM.\68\ In its
TSD for ACIMs, DOE in its preliminary analysis estimates the baseline
energy can drop from 10% below baseline (i.e., after other improvements
were made) to 18% below baseline when switching to R-290. The
refrigerant change increased the energy efficiency ratio (EER) from 6.4
to 7.4. When evaluating compressors for ACIMs, DOE found that R-290
compressors were consistently more efficient than R-404A ones over the
full capacity range studied (from approximately 1,000 BTU/h to 5,000
BTU/h). In six other types of ACIMs, DOE consistently found that the
energy use dropped by switching to R-290,\69\ and likewise found
improvements by switching to R-600a in three types of ACIMs.\70\
---------------------------------------------------------------------------

    \67\ See https://www.embraco.com/en/embraco-brings-to-ahr-expo-a-case-study-with-34-energy-savings-in-ice-machines.
    \68\ Technical Support Document: Energy Efficiency Program for
Consumer Products and Commercial and Industrial Equipment: Automatic
Commercial Ice Makers; EERE-2017-BT-STD-0022-0009_content (1);
available at www.regulations.gov.
    \69\ Based on ACIM type, energy use compared to baseline
declined 18% to 25%, 8% to 18%, 7% to 20%, 8% to 19%, 42% to 48%,
and 11% to 32%.
    \70\ Based on ACIM type, energy use compared to baseline
declined 0% to 8%, 20% to 22%, and 3% to 10%.
---------------------------------------------------------------------------

f. Contractor Training Costs
    As part of the Agency's consideration of the availability of
substitutes as directed by subsection (i)(4)(B), EPA is taking into
account, to the extent practicable, available information on contractor
training costs, including training related to substitutes for relevant
sectors and subsectors (e.g., certain RACHP and foam subsectors). EPA
obtained contractor training and exam cost data through a review of
publicly available literature, from industry trade and training
associations, and information submitted to EPA during the comment
period or in petitions under subsection (i). It is not feasible to
obtain information and data on all available training programs and
exams and our review represents an assessment to the extent practicable
of information in relevant sectors and subsectors for contractor
training costs. Some substitutes may require specialized or additional
training, knowledge, or expertise to ensure their safe handling and
use. This includes, but is not limited to, flammable (A3 or B3), lower
flammability (A2L or B2L), and higher toxicity (B1, B2L, B2, or B3)
refrigerants and other substitutes with unique or different
characteristics such as those operating at higher pressures than HFCs.
To the extent practicable, the Agency has considered the cost of
trainings to contractors for handling products and equipment containing
substitutes for HFCs or blends containing HFCs substitutes. In certain
situations, the Agency has endeavored to mitigate costs associated with
high demand for trainings associated with new substitutes by providing
additional time for compliance (and, in turn, for those trainings to
occur).
    Manufacturers and trade organizations often provide training and
certification beyond what is required under the regulations
implementing sections 608 and 609 of the CAA. This is not a new
practice, especially with the release of new equipment. As the
transition to lower-GWP refrigerants continues, more technicians are
expected to work with flammable refrigerants, and a variety of training
and education resources are anticipated to include the incorporation of
flammable refrigerants into existing curriculum. There are already
courses, trainings, and conferences across the country that focus on
lower-GWP refrigerants among the affected subsectors. Costs of
trainings are dependent on several factors, such as the organization
providing the training, how it is administered, and the location. In
some States, continued RACHP education is required as part of a State
licensing requirement; training on using

flammable refrigerants may be incorporated to fulfill this requirement.
    Certain applications in the foams and aerosols sectors may also
require safety training. In particular, the Occupational Safety and
Health Administration (OSHA) requires that contractors providing in
situ installation of spray foams, foam insulation, and aerosols receive
health and safety training regarding the hazards of working in confined
spaces and procedures to avoid injury from fall hazards. OSHA issued a
standard reflected in 29 CFR part 1926 subpart AA--Confined Spaces in
Construction, which requires that employers provide employees free
training to ensure that the employee understands the hazards of working
in a confined space. Additional trainings and exams are available
beyond the basic required safety training and may vary in costs
depending on the level and amount of training a contractor obtains.
g. Quantities of Regulated Substances Available From Reclaiming, Prior
Production, or Prior Import
    As part of the Agency's consideration of the availability of
substitutes as directed by subsection (i)(4)(B), EPA is taking into
account, to the extent practicable, information on quantities of HFCs
from reclamation and stockpiles of previously produced or imported
HFCs. EPA is providing additional information in the TSD American
Innovation and Manufacturing Act of 2020--Subsection (i)(4) Factors for
Determination: Quantities Available from Reclaiming, Prior Production,
or Prior Import.
    HFCs available from prior production or import that have been
stockpiled and HFCs that have been recovered and reclaimed can both
smooth transitions to alternative technologies and ensure that existing
equipment can continue to be used. The Agency knows from its experience
under the ODS phaseout the important role reclamation plays by
providing an ongoing supply of material. This is true not only for the
RACHP sector but a similar approach of recycling of fire suppressants
is also used for the fire suppression sector, where regulated
substances are recovered and tested and/or reprocessed to certain
industry purity standards. Some companies may also choose to stockpile
substances to ensure a continued supply that can meet their needs. EPA
cannot estimate how much material will be stockpiled for a particular
sector or subsector or by a particular company; however, the Agency can
consider this approach as a general matter.
    Information that EPA considered includes HFC reclamation data
submitted annually in accordance with the Clean Air Act section 608
reclamation program, codified at 40 CFR part 82, subpart F;
reclamation, production, and import data reported under 40 CFR part 84,
subpart A; \71\ data gathered to support development of the AIM Act
subsection (e) regulations contained in the docket for the 40 CFR part
84, subpart A rules; \72\ and data reported to the Greenhouse Gas
Reporting Program (GHGRP) under subparts OO and QQ.
---------------------------------------------------------------------------

    \71\ In addition to quarterly data, under 40 CFR 84.31, HFC
producers, importers, exporters, application-specific allowance
holders, reclaimers, and fire suppressant recyclers must annually
report the quantity of each regulated substance held in inventory as
of December 31 of each year.
    \72\ Available at www.regulations.gov, in Docket ID No. EPA-HQ-
OAR-2021-0044.
---------------------------------------------------------------------------

    In addition, EPA is developing proposed regulations under the
authority of subsection (h) of the AIM Act. Subsection (h)(1) of the
Act provides that ``[f]or purposes of maximizing reclaiming and
minimizing the release of a regulated substance from equipment and
ensuring the safety of technicians and consumers, the Administrator
shall promulgate regulations to control, where appropriate, any
practice, process, or activity regarding the servicing, repair,
disposal, or installation of equipment . . . that involves: (A) a
regulated substance; (B) a substitute for a regulated substance; (C)
the reclaiming of a regulated substance used as a refrigerant; or (D)
the reclaiming of a substitute for a regulated substance used as a
refrigerant.'' Such regulations, if finalized, could increase the level
of reclamation in the future, such that the data provided in the TSD
may be a conservative estimate of what may be available in the future.
3. How is EPA considering overall economic costs and environmental
impacts, as compared to historical trends?
    Subsection (i)(4)(C) directs the Agency to factor in, to the extent
practicable, overall economic costs and environmental impacts, as
compared to historical trends. The Act does not prescribe how EPA
should carry out its consideration of this factor, nor does the statute
clearly delineate what is meant by the phrase ``as compared to
historical trends.'' In light of the ambiguity, we interpret the
language of (i)(4)(C) as purposefully accommodating of many different
types and degrees of analysis of economic costs and environmental
impacts (including costs and impacts that may be difficult to quantify)
in part because the nature of EPA's action when applying this provision
can differ greatly depending on the circumstances.
    Subsection (i)(4)(C) applies both to EPA's action on subsection (i)
petitions and to EPA's rulemakings under subsection (i). Subsection (i)
requires EPA to grant or deny petitions within 180 days of receipt, a
time period that inherently limits the scope and depth of any potential
analysis under subsection (i)(4)(C). EPA's timeframe for promulgating a
rule subject to a granted petition is two years from the date of a
petition grant, and in undertaking a rulemaking, whether by negotiated
rulemaking or not, EPA will undoubtedly perform more in-depth analysis
of economic costs and environmental impacts than we would in the more
abbreviated statutory period allotted for petition decisions. As
worded, particularly read in light of subsection (i)(4)'s
acknowledgement that consideration of some factors will be limited by
practicability (i.e., ``to the extent practicable''), the provision has
flexibility to permit EPA to tailor its consideration of this factor
accordingly.
    We note also that subsection (i)(4)(C) applies to cases where EPA
is considering a broad swath of restrictions--such as this action,
which covers more than 40 subsectors--as well as cases where EPA is
contemplating a much more limited set of restrictions, potentially for
only one sector or subsector. As discussed in this section, EPA
reviewed multiple sources of information when factoring subsection
(i)(4)(C) into the use restrictions for this action. This information
included, but was not limited to, the Costs and Environmental Impacts
TSD, information previously developed by EPA concerning HFCs and
transitions, our experience with the ODS program, information developed
by the TEAP, the Montreal Protocol's Science Assessment Reports,
industry reports and commissioned studies (e.g., JMS Consulting in
partnership with INFORUM), journal articles, and other research. In
other actions under subsection (i), it may be appropriate in some
instances for EPA to prepare detailed analyses such those in the Costs
and Environmental Impacts TSD, but also times when new analyses of
similar detail would be unnecessary or not practicable.
    It is also not clear from the plain language of the statute what
information EPA should consider when thinking about ``historical
trends,'' and how EPA should ``compare'' ``overall'' economic cost and
environmental impact information about newly contemplated

restrictions to those trends. Here too the ambiguity of these phrases
accommodates consideration of a variety of information and comparisons
depending on the circumstances and the available information.
    In undertaking this action, EPA does not yet have historical
overall economic cost and environmental impact trends for previous use
restrictions, or transitions from HFCs to substitutes, under subsection
(i) to compare with the overall economic costs and environmental
impacts of the contemplated restrictions. However, it is practicable
and reasonable to in part interpret our obligation to factor in the
considerations under subsection (i)(4)(C) by looking at the overall
economic costs and the anticipated environmental impacts of the
restrictions as compared to a scenario where historical trends continue
into the future (i.e., ``business-as-usual''). For purposes of this
action, a reasonable reading of the business-as-usual scenario is the
conditions that would occur if only the Allocation Framework Rule and
the 2024 Allocation Rule were in effect. Therefore, the analysis in the
Costs and Environmental Impacts TSD uses as a baseline what would occur
absent the restrictions finalized in this rulemaking. As noted,
subsection (i)(4)(C) does not require a specific type of analysis, such
as the one EPA conducted for purposes of the Costs and Environmental
Impacts TSD, and we anticipate that the Agency could consider this
(i)(4) factor using a different type of analysis in the future.
    As this is the first set of restrictions under subsection (i)
requiring transitions from certain regulated substances in certain
sectors and subsectors, it is appropriate to consider information from
historical comparable technology transitions in similar contexts. As
noted elsewhere, HFCs are used mainly in the same sectors and
subsectors where ODS were used. EPA has considered the overall economic
costs and environmental impacts of actions taken under the CAA title VI
regulations on ODS in a memo \73\ available in the docket. EPA
acknowledges that the ODS phaseout and transitions from HFCs as a
result of this rule have their own unique regulatory features and
technological transitions at play, leading to different overall
economic impacts and environmental impacts. The memo discussing the
costs and environmental impacts of the ODS phaseout is included as
supplemental information and as a relevant benchmark, as the transition
to HFC substitutes will impact many of the same industries and entail,
in some cases, similar technological shifts.
---------------------------------------------------------------------------

    \73\ See ``Overview of CFC and HCFC Phaseout'' document in the
docket.
---------------------------------------------------------------------------

    One key historical trend observed during the ODS phaseout that may
be relevant to the HFC phasedown is that technology transitions did not
necessarily drive up the cost of products to the consumer or hurt the
performance of products. A clear example of this was discussed in a
2018 report of the TEAP.\74\ From 1972 through 2015, household
refrigerators sold in the United States underwent several design
changes in response to regulations requiring transition from ODS
refrigerant, ODS-containing insulation foam, and increased energy
efficiency. Over that time, the average capacity of refrigerators sold
in the United States also grew to accommodate consumer preferences.
Even as refrigerators became larger, more energy efficient, and
transitioned from use of ODS, the average price fell in real dollars.
Consumers not only benefitted from the lower initial purchase price,
but the greater energy efficiency also reduced consumers' electricity
costs. This example, and a similar trend seen in household unitary AC
units, are discussed in more detail in the report American Innovation
and Manufacturing Act of 2019: Compliance and Consumer Cost Estimates,
which can be found in the docket.\75\
---------------------------------------------------------------------------

    \74\ Decision XXIX/10 Task Force Report on Issues Related to
Energy Efficiency while Phasing Down Hydrofluorocarbons, Technical
and Economic Assessment Panel, UNEP, May 2018. Available at: https://ozone.unep.org/sites/default/files/2019-04/TEAP_DecisionXXIX-10_Task_Force_EE_May2018.pdf
    \75\ Consumer Cost Impacts of the U.S. Ratification of the
Kigali Amendment, JMS Consulting in partnership with INFORUM,
November 2018. Available in the docket.
---------------------------------------------------------------------------

    As described in the memo that summarizes the costs of the ODS
phaseout, the most comprehensive analysis was in a 1999 peer-reviewed
report from EPA to Congress.\76\ In that report, EPA summarized the
costs of the allowance allocation and reductions for CFCs, HCFCs,
halons, and methyl chloroform to be $18 billion (7 percent discount
rate) to $56 billion (2 percent discount rate) in 1990 dollars.\77\ It
was also noted that the transition to more energy efficient air
conditioning using alternatives to HCFC-22 could lower this cost by
$16.8 billion in 1990 dollars.\78\ As opposed to this net cost, the
Costs and Environmental Impacts TSD indicates that the transitions
envisioned would yield a net savings through 2050 of $4.2 billion (7
percent discount rate) to $8 billion (3 percent discount rate) in
compliance costs.
---------------------------------------------------------------------------

    \76\ Final Report to Congress on Benefits and Costs of the Clean
Air Act, 1990 to 2010; EPA 410-R-99-001 Nov 15, 1999.
    \77\ Approximately $36 billion and $111 billion, respectively,
in 2020 dollars.
    \78\ Approximately $33.3 billion in 2020 dollars.
---------------------------------------------------------------------------

    The primary goal of the ODS phaseout was to protect the ozone layer
in accordance with title VI of the CAA and the Montreal Protocol,
whereas the primary purpose of this action is to restrict the use of
higher-GWP HFCs, making the benefits difficult to compare. However, the
phaseout of ODS also provided climate change benefits, as most ODS are
also high-GWP greenhouse gases, as indicated by the exchange values for
the ODS that are listed in subsection (e)(1)(D) of the AIM Act.\79\
Although such benefits have not been calculated specifically for the
United States, we note that the U.S. was one of the largest producers
and consumers of ODS, and that the benefits from phasing out ODS can be
significant given the high GWPs of the most common ODS.
---------------------------------------------------------------------------

    \79\ Velders, Guus JM, et al. ``The importance of the Montreal
Protocol in protecting climate.'' Proceedings of the National
Academy of Sciences 104.12 (2007): 4814-4819.
---------------------------------------------------------------------------

4. How is EPA considering the remaining phasedown period for regulated
substances?
    Subsection (i)(4)(D) directs the Agency to factor in, to the extent
practicable, the remaining phasedown period for regulated substances
under the final rule issued under subsection (e)(3) of the AIM Act, if
applicable. In the Allocation Framework Rule (86 FR 55116, October 5,
2021), EPA established the allocation program under subsection (e) of
the AIM Act, which is codified at 40 CFR part 84, subpart A. A key
provision under subsection (e) requires EPA to phase down the
consumption and production of the statutorily listed HFCs on an
exchange value-weighted basis according to the schedule in the table in
subsection (e)(2)(C) of the AIM Act. The quantity of allowances
available for allocation for each calendar year decreases over time
according to the statutory phasedown schedule.
    Currently, the United States is at the first step of the HFC
phasedown. In 2023, HFC production and consumption is limited to 90
percent of the historical baseline. Additional reduction steps occur on
January 1 of 2024, 2029, 2034, and 2036, at which point HFC production
and consumption will continue at 15 percent of the baseline. Starting
with the allowances for calendar year 2024 the total quantity of

production and consumption allowances that may be allocated will drop
by one third--to 60 percent of baseline--and starting with calendar
year 2029 they will decline to 30 percent of baseline. Thus, most of
the phasedown will occur within the next six years. This reduction in
the supply of HFCs is an important factor in finalizing restrictions
under subsection (i) with compliance dates and GWP limits that are as
stringent as feasible under the analysis of all the (i)(4) factors.
    EPA also views this final rule as supporting the phasedown
schedule. While promulgated under a separate statutory provision under
the AIM Act, the restrictions on the use of HFCs will have a
complementary effect in meeting the HFC phasedown schedule by
facilitating necessary transitions to lower-GWP substitutes. This rule
supports innovation and advances the adoption of substitutes where
available, thereby reducing demand for HFCs. EPA anticipates new
substitutes and technologies will continue to emerge as the reductions
in the caps on production and consumption allowances continue.
Restricting the use of HFCs in sectors and subsectors that are better
positioned to transition to new substitutes and technologies is
consistent with subsection (i) and supports the overall production and
consumption phasedown.
    Title VI of the CAA similarly provided for prohibitions on the sale
or distribution in interstate commerce of certain products under
section 610 and for additional restrictions on use of certain ODS under
section 605(a). These restrictions supported the ODS phaseout. For
example, most of the nonessential products bans under section 610 were
established at the very beginning of the ODS phaseout program--ahead of
the overall CFC phaseout by a few years and ahead of the HCFC final
phaseout by a few decades. By banning the use of certain ODS where
substitutes were available, early transitions accrued additional
environmental benefits and supported the overall economy-wide
transition by removing uses of controlled substances that were no
longer necessary. At the time, in discussing some of the statutory
criteria to be considered in determining whether a product was
nonessential, EPA noted that ``where substitutes are readily available,
the use of controlled substances could be considered nonessential even
in a product that is extremely important.'' (58 FR 4768, January 15,
1993).
5. How did EPA determine the degree of the restrictions for each sector
and subsector?
    AIM Act subsection (i)(1) grants EPA authority to restrict by rule
the use of a regulated substance in the sector or subsector in which
the regulated substance is used, and these restrictions may be
exercised ``fully, partially, or on a graduated schedule.'' In
determining the degree of the restrictions--e.g., GWP level, how
partially or fully to restrict the use, and on what schedule--EPA
looked to the factors in subsection (i)(4). Specifically, we interpret
subsection (i)(4) as directing EPA to balance multiple factors in
establishing the level of the contemplated use restriction, and we
describe in this section the guiding principles and methodology EPA
employed in our consideration of those factors in developing the
restrictions established in this action. In short, EPA selected the
degree of restriction for each sector or subsector by weighing the
following considerations: maximizing environmental benefit while
ensuring adequate availability of substitutes (as informed by the
subsection (i)(4)(B) subfactors) and with consideration of how this
action comports with the overall economic costs and environmental
benefits compared to historical trends. With respect to all of our
information and analysis we strive to use best available data. We are
also mindful of the HFC phasedown schedule in ensuring that the use
restrictions support that schedule by reducing total U.S. demand for
HFCs by transitioning uses in sectors and subsectors where the Agency
has determined that substitutes are available.
    EPA is establishing restrictions on the use of HFCs by, for the
most part, setting GWP limits by sector or subsector. In section VI.B,
EPA highlights the benefits of using GWP limits, including achieving
environmental benefits, smoothing the transition from higher-GWP
substances, supporting innovation, providing regulatory certainty, and
harmonizing with approaches taken by other governments in establishing
similar requirements.
    Because the use restrictions were requested by numerous
stakeholders, representing a broad range of interests (regulated
industry, environmental and public health organizations, and State and
local governments), EPA considered the petitions--either in the form of
GWP limits or specific substances to be restricted--as the starting
point for the level of the restrictions. In some cases, petitioners
provided information about substitutes that are already in use or would
soon be ready to be in use in the affected sectors and subsectors and
attested to the achievability (technologically, regulatory, economic,
and otherwise) of certain substitutes. The substitutes discussed in the
petitions and supporting information had lower GWPs, and thus reduced
adverse impacts on climate, compared to the regulated substances for
which a use restriction was requested. Many of the petitioners are the
entities (or trade associations representing those entities) developing
substitutes or manufacturing products using substitutes.
    The impetus for this rulemaking, in part, was to address the
granted petitions. Therefore, the restrictions requested in those
petitions, including specific substances or GWP limits, and the timing
of those restrictions, were a natural starting point for the Agency's
inquiry. However, as a starting point, EPA was clear in the proposed
rule that the Agency was not obligated to propose a rule restricted to
the petitions. Subsection (i)(4) requires that EPA take into account,
to the extent practicable, the factors described in section VI.E of
this preamble. In following this statutory directive, EPA considered
the (i)(4) factors collectively, with no single (i)(4) factor (or
subfactor) driving the restrictions for any sector or subsector.
Collective consideration of the (i)(4) factors is consistent with the
statutory text, which directs EPA to account for all the factors, to
the extent practicable, in carrying out a rulemaking under subsection
(i), and which does not state that one factor should carry more weight
than the others. Further, accounting for the (i)(4) factors together
enables EPA to take a holistic approach in facilitating transition to
substitute technology, one that considers the availability of
substitutes, overall economic costs and environmental impacts, as
compared to historical trends, and the HFC phasedown schedule codified
by the Allocation Framework Rule.
    The direction in subsection (i)(4)(C) to factor in overall economic
costs and environmental impacts as compared to historical trends does
not have a clear meaning in the context of selecting the degree of a
restriction for a given sector or subsector. The provision's focus on
an ``overall'' comparison makes direct application of this factor in
setting a level of restriction for a specific sector or subsector less
practicable. However, the focus in subsection (i)(4)(C) on ``economic
costs'' and ``environmental impacts'' still provides direction to the
Agency that cost and environmental considerations are relevant factors
for EPA to consider in setting the level of a use restriction under
subsection (i),

and we address how EPA did so in the following paragraphs.
    For these restrictions, in factoring in environmental impacts, our
aim was generally to establish GWP limits for each sector or subsector
at the lowest supportable level while considering the other factors
under subsection (i), specifically, availability of substitutes and
cost, as well as considerations of implementation and enforcement. It
is reasonable to prioritize maximizing the climate change benefits of
restricting the regulated substances that are the focus of this rule,
given that these environmental impacts are and have been one of the
central concerns with the use of HFCs. Much of the information relied
upon in our analysis of available substitutes comes from SNAP, which
evaluates and identifies as ``acceptable'' those substances that reduce
overall risk to human health and the environment, as well as the TEAP
reports which speak to human health and environmental considerations,
the granted petitions, and information from State and foreign
government regulations.
    Therefore, in selecting the levels of restrictions for each sector
and subsector, we set the GWP limit at the lowest level that will
provide a sufficient range of substitutes for applications within a
subsector. EPA projects the cumulative environmental impact of these
restrictions to be significant; with an average annual additional \80\
emission reduction of 4 to 34 MMTCO2e, and an average annual
additional consumption reduction of 28 to 43 MMTCO2e, from
2025 through 2050 (see Costs and Environmental Impacts TSD).
---------------------------------------------------------------------------

    \80\ These reductions would be in addition to the consumption
reductions from the Allocation Rules.
---------------------------------------------------------------------------

    EPA did not set the level of restrictions for this rule at
precisely the GWPs of identified available substitutes in each sector
or subsector. Instead, EPA is establishing GWP limits at regular
intervals--i.e., 150 GWP, 300 GWP, and 700 GWP. This approach has
advantages over a methodology that tightly tailors the GWP limit for
each subsector to the specific GWPs of the currently identified
available substitutes for that particular sector or subsector (e.g.,
establishing GWP limits of 237, 258, and 290 based on the particular
substitutes currently available in three different subsectors).
Establishing limits at regular intervals avoids changing the status of
an alternative caused by minor discrepancies in the methodology used to
calculate GWPs; \81\ promotes development of new variations on
substitutes that are still within the permissible range; allows for use
of a wider range of substitutes (recognizing that not every substitute
is necessarily available for each use within a subsector); and eases
implementation of the restrictions for regulated parties, consumers,
and enforcement.
---------------------------------------------------------------------------

    \81\ For example, using the methodology finalized in this rule,
EPA calculates that R-452B has a GWP of 698 and thus meets the 700
GWP limits.
---------------------------------------------------------------------------

    To ensure adequate availability of substitutes, EPA looked at a
range of information relevant to the subfactors provided in subsection
(i)(4)(B) from a variety of sources. In general, EPA aimed to establish
GWP limits at a level that would include multiple available substitutes
that could be used in that sector or subsector (taking into
consideration the various (i)(4)(B) subfactors to the extent
practicable). In the following sections, we provide detailed
information regarding the availability of substitutes for each sector
and subsector.
    Our methodology for setting the levels of the use restrictions also
factored in considerations of cost, both in identifying availability of
substitutes and in assessing overall costs of the levels of the
restrictions. Some of the subfactors in subsection (i)(4)(B) for the
Agency to take into account when determining ``availability'' are
explicitly or implicitly related to cost. Subfactors that explicitly
relate to cost include commercial demands (there would be no demand for
a substitute that caused a product to be so costly as to be
unmarketable), consumer costs, affordability for residential and small
business consumers, and contractor training costs. Other subfactors
that are not explicitly related to cost contain implicit considerations
of cost. For example, a company generally would not invest in
demonstrating that use of a substitute is technologically achievable in
a sector or subsector if the use of that substitute was so cost
prohibitive that it would never actually be adopted. The Agency
factored in these cost subfactors to the extent practicable when
considering availability of substitutes.
    Subsection (i)(4)(C) also specifically directs EPA to factor in, to
the extent practicable, overall economic costs as compared to
historical trends, and as discussed above, the Agency has considered
numerous sources of information as we developed this rule, including
the cost findings summarized in the Costs and Environmental Impacts
TSD. As discussed in that TSD, we anticipate that the incremental
economic cost of the restrictions will result in a savings to the
regulated industry, i.e., that complying with the use restrictions and
transitioning from higher-GWP regulated substances to lower GWP
substitutes will, on the whole, reduce costs for industry.
    In summary, in carrying out a rulemaking under subsection (i), EPA
views subsection (i)(4)(A) through (D) as providing overarching
direction for setting restrictions under this section. Subsection
(i)(4)(B) also requires the Agency to examine the particular subfactors
listed therein for the sector or subsector in order to determine
whether a substitute is available for use in that sector or subsector.
Therefore, in the following section addressing the final restrictions
and compliance dates for each sector and subsector, EPA has focused the
bulk of its discussion on the identification of available substitutes
and the Agency's consideration of the relevant sub-factors informing
availability.

F. For which sectors and subsectors is EPA establishing restrictions on
the use of HFCs?

    This section provides a description of each sector or subsector
subject to the restrictions in this rule, the final use restrictions,
and compliance dates, and EPA's assessment of the availability of
substitutes for each sector or subsector (see section VI.E.5). In
addition, this section includes summaries of comments on specific
sectors and subsectors and EPA's responses.
1. Refrigeration, Air Conditioning, and Heat Pumps
    Subsectors in the RACHP sector typically use a refrigerant in a
vapor compression cycle to cool and/or dehumidify a substance or space,
such as a refrigerator cabinet, room, office building, or warehouse.
The equipment in this subsector, for the purposes of this rule,
includes self-contained, factory-completed products and larger, field-
assembled systems. EPA recognizes that these terms may be used under
SNAP and the refrigerant management regulations in 40 CFR part 82,
subpart F.
a. Industrial Process Refrigeration (IPR)
    IPR systems are used to cool process streams at a specific location
in manufacturing and other industrial processes (e.g., chemical,
pharmaceutical, petrochemical, and manufacturing industries). IPR
systems are directly linked to the industrial process, meaning the
refrigerant leaving the condenser and metering device is

delivered directly to the heat source before returning to the
compressor. This also includes appliances used directly in the
generation of electricity. Specialized refrigerated laboratory
equipment, such as that used in the pharmaceutical industry, may fall
under this subsector if it operates at temperatures above -62 [deg]C (-
80 [deg]F), and is not considered to be very low temperature
refrigeration equipment.
    Where one system is used for both IPR and other applications (such
as cooling a room or building in which the industrial process is
located), EPA considers it to be an IPR system if 50 percent or more of
its operating capacity is used for IPR. Cooling or IPR that involves
using a chiller, e.g., to circulate a secondary fluid to the point at
which heat is removed from the process, or to cool a room or building
as explained in this section, is regulated as a chiller and is
discussed in section VI.F.1.j. IPR equipment not using a chiller is
regulated as part of the IPR subsector and discussed in this section.
    In the proposed rule, EPA included data centers and data servers in
the description of applications that the Agency considers to be IPR. In
this final rule, EPA is creating a separate subsector for data centers,
information technology equipment facilities (ITEF), and computer room
cooling equipment which includes appliances used for large scale
cooling of server farms, ITEF, computer rooms, data centers, data
servers, communication rooms, and other spaces dedicated to maintaining
the operating temperature of electronic technologies. This subsector is
discussed in section VI.F.1.b.
    Many types of foods require refrigeration during the production
process. EPA considers refrigerating equipment used during the
production of food and beverages in an industrial setting to fall under
IPR. If the food production process requires cooling done directly by a
refrigerant, either at the point where cooling is required or to cool a
room or building in which the cooling is required, the equipment falls
within the IPR subsector. If instead a chiller is used to cool a
secondary fluid (e.g., water) that then provides the required cooling,
EPA considers the use to be in the chillers for IPR subsector. The IPR
subsector includes all equipment and operations that use a refrigerant
to make and prepare food that is not immediately available for sale (or
supply, if the food is not ``sold'') to the consumer and would require
shipping or delivering it, possibly through intermediate points, to the
point where such sale would occur. This could include facilities where
food is processed and packaged by the food producer, such as a meat
processor that prepares and packages individual cuts of meat within a
single facility or building while maintaining the required
temperatures. Although such facilities may be designed in a fashion
similar to a cold storage warehouse, the fact that items are being
processed by the food producer indicates that the application falls in
the IPR subsector. However, if a food producer operates a refrigerated
storage area solely for the holding of already packaged food, and
possibly for packing such food in larger containers or bundles for
shipment, that application would fall within the cold storage warehouse
subsector.
    Another example of an IPR system is a ``blast cooler'' or ``blast
freezer.'' In this context, ``blast cooler'' or ``blast freezer''
refers to a type of equipment in which cold air is supplied and
circulated rapidly to a food product, generally to quickly cool or
freeze the food before damage or spoilage can occur. This is the same
description as the Agency has previously used for this equipment (see
80 FR 42901, July 20, 2015). Such equipment might be used as part of a
food production line in an industrial setting. They also can be placed
separately at public facilities including hospitals, schools,
restaurants, and supermarkets. These public facilities might use the
blast cooler or freezer on food that they will store for later use
after they receive it from a vendor or that they cook or prepare as
part of their operations. Such units might also be placed near
entranceways to cold storage warehouses, for instance to receive food
refrigerated and shipped at one temperature and then to bring it down
to a lower temperature for storage.
    IPR systems typically have large refrigerant charges to satisfy the
significant cooling demands throughout the facility. Historically,
facilities have commonly used R-717, hydrocarbons, CFCs, HCFCs, and
HFCs including but not limited to R-12, R-22, R-404A, R-507A, and R-
134a.
What restrictions on the use of HFCs is EPA establishing for IPR
systems?
    EPA is prohibiting the use of HFCs and blends containing HFCs in
IPR systems at different GWP thresholds (150, 300, and 700) depending
on a combination of factors including the size, refrigerant temperature
entering the evaporator, and design of the system. These GWP limits
apply to new IPR systems other than chillers used for IPR, which are
discussed in section VI.F.1.j. EPA is establishing a 150 GWP limit for
new IPR systems with refrigerant charge capacities of 200 lb or greater
with refrigerant temperature entering the evaporator at -30 [deg]C (-22
[deg]F) or above beginning January 1, 2026.\82\ EPA is establishing a
300 GWP limit for new IPR systems with refrigerant charge capacities
less than 200 lb and for the high temperature side of cascade systems
with refrigerant temperature entering the evaporator at -30 [deg]C (-22
[deg]F) or above, also beginning January 1, 2026. If the low
temperature side of a cascade system has a charge capacity less than
200 lb with refrigerant temperature entering the evaporator at -30
[deg]C (-22 [deg]F) or above, then the GWP limit is 300, beginning
January 1, 2026. If the low temperature side of a cascade system has a
charge capacity of 200 lb or greater with refrigerant temperature
entering the evaporator at -30 [deg]C (-22 [deg]F) or above, EPA is
prohibiting the use of HFCs and HFC blends with a GWP of 150 or greater
in the low temperature side of the cascade beginning January 1, 2026.
In new IPR systems where the refrigerant temperature entering the
evaporator is equal to or above -50 [deg]C (-58 [deg]F) but less than -
30 [deg]C (-22 [deg]F), the GWP limit is 700 beginning January 1, 2028.
EPA is currently not establishing restrictions for new IPR systems with
refrigerant temperature entering the evaporator below -50 [deg]C (-58
[deg]F).\83\
---------------------------------------------------------------------------

    \82\ The refrigerant HFC-134a has a boiling point slightly above
-30 [deg]C (-22 [deg]F) and R-717 has a boiling point slightly lower
at -33.3 [deg]C. R-717, HFC-134a, and similar refrigerants like R-
450A and R-513A work above this temperature.
    \83\ The refrigerants R-404A and R-410A have bubble (boiling)
points slightly above -50 [deg]C (-58 [deg]F). R-404A and similar
refrigerants like R-448A, R-449A, R-449B, R-452A, and R-410A and
similar refrigerants like HFC-32 and the R-454 series, work above
this temperature.
---------------------------------------------------------------------------

    In considering the availability of substitutes under subsection
(i)(4)(B), EPA identified several substitutes \84\ as available for use
in IPR systems in place of the higher-GWP substances that EPA is
prohibiting. These available substitutes for all non-chiller IPR
systems include HCFO-1224yd(Z) (GWP less than 1), R-717 (GWP 1), R-1270
(GWP 1.8), R-290 (GWP 3.3), and

R-600 (GWP 4).\85\ EPA is aware of a statement by one stakeholder that
R-717 and hydrocarbons (R-600, R-1270, R-290) were used in 90 to 95
percent of the market share for IPR systems in 2019, indicating the
technological achievability and commercial demand for systems using
available substitutes.\86\
---------------------------------------------------------------------------

    \84\ EPA notes for all substitutes identified in section VI.F of
this preamble, not every substitute listed is necessarily available
across all U.S. markets. For example, in some cases, substitutes may
be technologically and economically viable and may be in use in
international markets but may be unavailable in specific U.S. market
for other reasons such as building code restrictions. The lists of
``available'' substitutes therefore includes some substances which
may only be ``potentially available'' in some areas. EPA also notes
that not all of the identified substitutes are listed as acceptable
under the SNAP program. See section VI.E.2 of this preamble for a
discussion on availability of substitutes.
    \85\ EPA notes that the GWP limits apply only to regulated
substances and blends containing a regulated substance (e.g., R-
471A, R-454A, and R-454C). The GWPs of the other substitutes, which
do not contain a regulated substance, are provided here and in
subsequent sections for context only.
    \86\ AHRI Letter Responding to CARB's Request for Input and
Clarifications Following the August 6, 2019, Public Meeting for
Industrial Process Refrigeration and Transport Refrigeration
Equipment. Available in the docket.
---------------------------------------------------------------------------

    In addition to the substitutes that are already available for use
in this subsector, EPA has recently proposed to list HFO-1234yf, HFO-
1234ze(E), R-454A, R-454C, R-455A, R-457A, and R-516A (with GWPs of 1,
1, 237, 146, 146, 137, and 140 respectively) as acceptable, subject to
use conditions, under SNAP for use in IPR (88 FR 33722, May 24, 2023).
These proposed listings meet the GWP limit of 300 for this subsector,
and all except R-454A meet the GWP limit of 150. Although the already
available substitutes have been evaluated by EPA to be sufficient to
meet these restrictions, the potential for a greater array of options
in the future may further smooth the transition from higher-GWP HFCs.
EPA continues to encourage innovation of refrigerants that meet these
restrictions and anticipates the number of substitutes available for
use in IPR will continue to grow.
    Comment: One commenter expressed support for the proposed January
1, 2025, transition date for commercial refrigeration, including IPR.
Several commenters requested a January 1, 2026, transition date for
commercial refrigeration equipment, including IPR, citing the need for
building codes to be updated and stating that the IPR industry
(including OEMs, refrigerant suppliers, technicians, and system
designers) is not ready in all regions and applications. One commenter
added that even meeting a January 1, 2026, transition date does not
allow enough time for OEMs and distributors to adjust their supply
chain processes.
    Response: In this final rule, for IPR equipment with a refrigerant
temperature entering the evaporator greater than or equal to -30 [deg]C
(-22 [deg]F), EPA is extending the compliance date to January 1, 2026.
For IPR equipment with a refrigerant temperature entering the
evaporator from -30 [deg]C (-22 [deg]F) to -50 [deg]C (-58 [deg]F), EPA
is extending the compliance date to January 1, 2028, for reasons
discussed in this section.
    The additional year for most IPR equipment provides time for the
adoption of building codes that incorporate updated safety standards
(e.g., UL 60335-2-89, ASHRAE 15-2022) allowing for the safe use of
lower-GWP refrigerants.87 88 The International Building Code
is scheduled to be updated in 2024, which would then need to be adopted
by State and local jurisdictions. Delaying the compliance date to
January 1, 2026, provides time for jurisdictions to make these updates.
However, EPA can consider a substitute to be available before every
building code in every jurisdiction across the United States permits
its use. See section VI.E.2.d of the preamble for further discussion on
how building codes affect the availability of substitutes. Based on
EPA's assessment of the availability of substitutes under subsection
(i)(4)(B), additional time is warranted for a transition in IPR
systems, with the compliance date depending on the temperature of the
refrigerant entering the evaporator. The Agency is extending the
compliance date to January 1, 2028, for IPR systems with refrigerant
temperature entering the evaporator from -30 [deg]C (-22 [deg]F) to -50
[deg]C (-58 [deg]F) because, as discussed further below in this
section, there are fewer technologically achievable refrigerants with a
sufficiently low boiling point such that they may be used in equipment
used at lower temperatures. Therefore, more time may be needed to
identify, test, and implement appropriate substitutes in such
equipment.
---------------------------------------------------------------------------

    \87\ ASHRAE. (2022). ANSI/ASHRAE Standard 15-2022: Safety
Standard for Refrigeration Systems.
    \88\ UL Standard. (2021). Household and Similar Electrical
Appliances--Safety--Part 2-89: Particular Requirements for
Commercial Refrigerating Appliances and Ice-Makers with an
Incorporated or Remote Refrigerant Unit or Motor-Compressor
(Standard 60335-2-89, Edition 2).
---------------------------------------------------------------------------

    The additional year for most IPR systems will also help mitigate
other issues identified by commenters regarding the industry's ability
to transition, such as the refrigerant supply chain, the timeline for
new equipment design and testing, and need for specialized technician
trainings. One additional year is in agreement with several industry
commenters and provides time for EPA to continue its review of lower-
GWP substitutes, such as the proposed SNAP Rule 26 discussed previously
(88 FR 33722, May 24, 2023), which will likely provide even more
refrigerant options. For these reasons, EPA is providing one additional
year for most of the IPR subsector, and three additional years for IPR
systems with refrigerant temperature entering the evaporator from -50
[deg]C to -30 [deg]C (-58 [deg]F to -22 [deg]F), to comply with the GWP
restrictions established in this final rule.
How does charge size and system design affect the availability of
substitute refrigerants?
    EPA is establishing different GWP limits for new IPR, remote
condensing unit, supermarket, and cold storage warehouse systems based
on the refrigerant charge capacity of the system. Setting different GWP
restrictions based on the charge of the system is consistent with
information provided by petitioners, EPA's understanding of technical
challenges inherent to smaller charge capacity systems, and industry
safety standards. In general, systems with smaller refrigerant charge
capacities (i.e., smaller than 200 lb) are located inside and in
potentially confined spaces where a leak of a flammable refrigerant
could result in concentrations of concern. Conversely, larger
refrigerant charge capacities (i.e., greater than or equal to 200 lb)
are typically located outside the refrigerated space, where safety
standards and building codes allow for greater use of flammable and
lower flammability refrigerants. Setting different GWP limits for this
subsector based on the charge capacity of equipment will increase the
number of available substitutes where lower-GWP substitutes are
limited.
    Each of the restrictions adopted in this action is tailored to the
subsector-specific applications and availability of substitutes for
those applications. Specifically, for smaller-footprint applications
(i.e., spaces with lower total air volume where smaller amounts of
leaked refrigerant could disproportionately increase in concentration)
in these subsectors, the use of A2Ls (lower flammability refrigerants)
is limited by the product safety standard UL 60335-2-89. This standard,
which can be referenced by building codes, sets charge limits for A2L
refrigerants used indoors to 260 times the lower flammability limit
(LFL, in kg/m\3\). This allowance is near or under 200 lb for most A2L
refrigerants. For example, this restriction would allow up to 176 lb of
HFC-32 in a single refrigeration circuit (87 FR 45522, July 28, 2022;
88 FR 26400, April 28, 2023). However, in certain applications, safety
standard ASHRAE 15 will apply to equipment with charge capacities above
this threshold, enabling the use of larger refrigerant charges by
requiring

additional mitigation strategies, such as increased air exchange to
minimize the concentration of leaked refrigerant in the air. Therefore,
larger systems covered by ASHRAE 15 are less limited in their
refrigerant options when complying with safety standards incorporated
in building codes.
    EPA proposed to differentiate the subsection (i) restrictions for
these subsectors based on refrigerant charge capacity to conform with
applicable safety standards, in consideration of the (i)(4)(B) factors,
which direct the Agency to consider safety, to the extent practicable,
in assessing availability of substitutes. Using a 200 lb charge
capacity threshold, rather than a lower one such as 50 lb as suggested
by some commenters, allows for greater availability of technologically
achievable substitutes in IPR, retail food remote condensing units,
retail food supermarket systems, and cold storage warehouse systems of
all sizes. Systems with refrigerant charge capacities less than 200 lb
are restricted from using certain lower-GWP refrigerant options by
safety standards, and thus require a higher GWP limit to ensure the
availability of substitutes for use in these subsectors.
    EPA has also considered the availability of substitutes when
cascade systems are used in new IPR, supermarket, remote condensing
unit, and cold storage warehouse systems. A cascade system is a design
option which consists of two independent refrigeration systems that
share a common cascade heat exchanger. They are often employed in
applications when the required temperature is very low. Each side of a
cascade system uses a different refrigerant that is most suitable for
the given temperature range. High temperature systems, or the ``high
temperature side,'' have typically used HFCs as a refrigerant; however,
it is technologically achievable in some cases and has become more
common to use R-717. For low temperature systems, or the ``low
temperature side,'' low boiling point refrigerants such as R-744 and R-
508B have been used. Considerations for the choice of refrigerant on
the high and low temperature sides of cascade systems are influenced by
many factors including, but not limited to, a refrigerant's toxicity
and flammability, its temperature glide, and its suitability for the
temperature application specifications.
    In its consideration of safety and building codes under subsection
(i)(4)(B), to the extent practicable, EPA understands that the use of
flammable or toxic refrigerants, such as R-717, on the high temperature
side of a cascade system may be limited in certain circumstances (e.g.,
in areas that are heavily populated or based on building codes and/or
standards). Therefore, EPA is establishing a higher GWP limit for HFCs
used in the high temperature side of cascade systems to allow
sufficient refrigerant options to comply with local building codes and
industry safety standards. Because the high temperature side of a
cascade system typically enters the building (i.e., in the machinery
room), some refrigerants such as R-717 may not be allowed by building
codes or may be limited in the charge size allowed. On the other hand,
the current edition of safety standard UL 60335-2-89 includes
provisions that support higher charge sizes for A2L refrigerants,
including some that meet a GWP limit of 300 but not 150, such as R-454A
and R-457B. A GWP limit of 300, as compared to a GWP limit of 150, also
allows for a greater array of available substitutes, such as R-515B
which was recently listed as acceptable under SNAP Notice 38 (88 FR
61977, September 8, 2023) and R-480A which is pending SNAP review,
which will further ease the transition to lower-GWP refrigerants. EPA
notes that the applicable GWP limit for the low temperature side of a
cascade system is dictated by the charge size of the low temperature
side by itself.
    Comment: Some commenters from industry generally supported the
proposed GWP limits based upon charge capacity thresholds for
refrigeration (i.e., GWP limit of 300 for refrigeration systems with a
refrigerant charge capacity of less than 200 lb and GWP limit of 150
for refrigeration systems with a refrigerant charge capacity of 200 lb
or more), including IPR systems, retail food refrigeration (remote
condensing units and supermarket systems), and cold storage warehouses.
Three other commenters recommended a single GWP limit for each of these
subsectors, regardless of the equipment's charge size. A couple of
commenters stated that could incentivize manufacturers to move to
higher-GWP HFCs in systems with smaller charges. One commenter
requested a 150 GWP limit, citing adequate availability of current
refrigerant options below that level. They asserted that a 300 GWP
limit for certain charge sizes and systems was unnecessarily high,
overly complicated, and could stifle innovation of very low-GWP
refrigerants. Another commenter requested a 10 GWP limit for all
equipment in these four subsectors, claiming there are no currently
available substitutes between 10 and 300 GWP.
    Several commenters agreed with establishing two GWP limits for
these subsectors by charge capacity, but urged EPA to adopt a 150 GWP
limit for IPR, retail food refrigeration, and cold storage warehouses
with a charge capacity threshold of 50 lb, instead of 200 lb as
proposed. In support of shifting the threshold to 50 lb, these same
commenters noted that California's regulations establishing GWP limits
and EPA's section 608 Refrigerant Management Program both use 50 lb as
a charge capacity threshold and that having the same charge capacity
threshold as California's GWP restrictions would allow for nationwide
consistency instead of a patchwork of requirements. They also noted
that updated safety standards and building codes have made a range of
substitutes available for use in this subsector for equipment with
charge sizes between 50 and 200 lb. Another commenter described a 10 lb
charge capacity cutoff as more appropriate for these subsectors than
200 lb for purposes of safety, but still requested a single GWP limit
regardless of charge size.
    These same commenters also disagreed with EPA's proposal to set a
separate GWP limit for the high temperature side of cascade systems.
Instead, they requested that EPA group cascade systems with other types
of direct refrigeration systems in the subsector containing a single
refrigerant loop. Such restrictions would be similar to California's
regulations, which do not include a separate requirement for cascade
systems. One commenter stated that there does not appear to be a clear
rationale articulated in the proposed rule for separating cascade
systems into a separate subsector category for GWP limit, nor any
criteria or requirement limiting the HFC or HFC-blend charge size of
the refrigerant used in the high temperature side of a cascade system.
    Several commenters pointed to the availability of substitutes below
150 GWP, such as R-744 and R-717, making the proposed 300 GWP limit
unnecessarily high for equipment of certain charge capacities (ranging
from no lower limit to 50 lb) and for the high temperature side of
cascade systems. One commenter acknowledged that EPA has assessed R-717
as being prohibitively toxic for use in certain locations based on
building codes, but they asserted that R-717 may only be prohibited by
a small number of localities and stated that it is otherwise a suitable
refrigerant option to meet a 150 GWP limit in most cases. This
commenter stated that cold storage

warehouses and IPR systems have widely used R-717, historically, and
they claimed R-744 is a suitable alternative in cases where R-717
cannot be used. Another commenter noted that continuing to use HFC
blends up to a GWP of 300 in new systems, especially in sectors where
refrigerant leaks are widespread, poses dramatically more harm to the
climate than use of non-HFCs and expressed concern that new
refrigeration systems will place significant demand on a dwindling
supply of HFCs when it will be needed to service existing equipment in
other subsectors such as residential AC.
    Response: EPA did not propose and is not finalizing a GWP limit of
10 for IPR, remote condensing units, supermarket systems, and cold
storage warehouses. EPA agrees with commenters that some of the
refrigerants available for use in these subsectors, such as R-744 and
R-717, have GWPs of less than 10. As noted in section VI.E.5, this
action establishes GWP limits at regular, grouped intervals, to ease
compliance and enforcement and also to ensure that there are adequate
available substitutes for various applications within the subsector.
Some of the lowest-GWP refrigerants, particularly those with non-
fluorinated chemistry, may not be appropriate in all situations (e.g.,
R-717). Moreover, the GWP limits EPA is finalizing allow for additional
refrigerants to be used and for continued innovation. The Agency does
not agree that this approach will unnecessarily incentivize the use of
higher-GWP refrigerants than would otherwise have been used, and is
finalizing restrictions consistent with our review of the (i)(4)
factors for each of the sectors and subsectors.
    After review of the comments, EPA is finalizing the refrigerant
charge capacity threshold at 200 lb for non-chiller IPR equipment, with
refrigerant entering the evaporator (for IPR systems that are not
chillers) with a temperature of -30 [deg]C (-22 [deg]F) or above, as
proposed. For purposes of subsection (i) and its evaluation of the
availability of substitutes for use in a sector or subsector, EPA is
aligning the refrigerant charge capacity threshold with applicable
safety standards (e.g., UL 60335-2-24, UL 60335-2-40, and UL 60335-2-
89) rather than aligning with thresholds established by States. EPA
recognizes there may be benefits to greater consistency between
regulatory requirements. However, EPA must consider the (i)(4) factors,
to the extent practicable, and these lead EPA to base the GWP threshold
on the industry safety standards, which limit the allowable charge of
flammable refrigerants based on the flammability limit of each
refrigerant to minimize risk from their use. In particular, the
industry safety standard for commercial refrigeration equipment, UL
60335-2-89, restricts charge sizes of A2L refrigerants at approximately
200 lb in a single circuit in equipment where leaks would likely enter
an occupied space, whereas ASHRAE 15 allows for larger charge sizes in
machinery rooms and outdoors by requiring additional mitigation
strategies, such as certain rates of air exchange. Equipment installed
in machinery rooms or outside has greater flexibility to meet the
requirements of safety standards and building codes, while smaller
equipment is more constrained by available space and may need more
refrigerant options that minimize the footprint of refrigerating
systems. Therefore, by harmonizing charge capacity thresholds with UL
60335-2-89, EPA is ensuring adequate availability of substitutes for
equipment with charge capacities below 200 lb.
    Concerning the suggestion to use a 50 lb charge capacity cutoff,
EPA's refrigerant management program under CAA section 608 applies leak
repair requirements to certain appliances with a full charge of 50 or
more pounds of any ODS refrigerant or blend containing an ODS
refrigerant (see 40 CFR 82.157(a). The factors for determination of
availability of substitutes listed in subsection (i)(4) of the AIM Act
do not lead the Agency to conclude that aligning the charge capacity
threshold for these subsectors' restrictions with the threshold used
for ODS leak repair requirements is appropriate. The refrigerant charge
capacity threshold of 10 lb was suggested by one commenter as being
more technically appropriate as a way of addressing safety than 200 lb
without explanation. EPA therefore does not agree that 10 lb is a more
appropriate charge capacity threshold than 200 lb. Further discussion
on EPA's decision to choose a 200 lb cutoff to determine GWP limits for
IPR, remote condensing units, supermarket systems, and cold storage
warehouses can be found earlier in this section.
    EPA considers it unlikely that establishing size thresholds will
create an incentive to build more smaller refrigeration systems rather
than fewer large refrigeration systems. Drivers for selection of a
commercial refrigeration system, such as cost, amount of product
needing to be cooled, ability to control temperature, durability,
support from the vendor, and ease of servicing, are not likely to push
the system user uniformly toward purchasing a refrigerant with a GWP of
300 compared to a refrigerant with a GWP of less than 150. Rather, EPA
expects that a company would use a smaller system with a refrigerant
with a GWP between 150 and 300, such as the HFC/HFO blends R-454A or R-
515B, instead of a lower-GWP refrigerant, such as R-744 (GWP 1), or the
HFC/HFO blend R-454C (GWP 146) if they determined refrigeration systems
with lower-GWP refrigerants would take up too much space.
    EPA also disagrees with the suggestion to remove the 300 GWP limit
for the high temperature side of cascade systems. Technical constraints
related to temperature, pressure, efficiency, and glide limit the
available refrigerants for the high temperature side of cascade
systems. As discussed in the proposed rule (87 FR 76775; December 15,
2022), building codes and safety considerations may also limit the
availability of flammable and/or toxic refrigerants in the high
temperature side of cascade systems. By establishing a GWP limit of
300, rather than 150, additional substitutes are available that
overcome the technical constraints and subsection (i)(4) factors that
limit the number of refrigerant options in subsectors using cascade
systems.
How does operating temperature affect the availability of substitute
refrigerants?
    Comment: Several commenters suggested that GWP limits for non-
chiller IPR systems be based on operating temperature ranges, similar
to the current European Union (EU) F-Gas regulations \89\ and CARB
regulations. A few of these commenters suggested EPA provide
flexibility with higher GWP limits for systems with lower temperature
ranges. One such commenter requested a GWP limit of 700 for IPR
equipment with refrigerant evaporating temperatures greater than -25
[deg]C (-13 [deg]F) and a 2,200 GWP limit for IPR equipment with
refrigerant evaporating temperatures from -25 [deg]C (-13 [deg]F) to -
45 [deg]C (-49 [deg]F). That commenter stated that flammable and toxic
alternatives that meet the original GWP limits of 150 or 300 would not
be viable for new or retrofit IPR facilities due to safety risks,
technical feasibility, and cost. Several commenters also requested
exemptions from restrictions

for IPR systems using flooded or liquid overfed evaporators.
---------------------------------------------------------------------------

    \89\ European Union Law. 2014. Regulation (EU) No 517/2014 of
the European Parliament and of the Council of 16 April 2014 on
fluorinated greenhouse gases and repealing Regulation (EC) No 842/
2006 Text with EEA relevance. Available at: http://eurlex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2<IP_ADDRESS>5.01.ENG.
---------------------------------------------------------------------------

    Regarding IPR systems operating at colder temperatures, many
commenters requested clarification for systems with very low
temperatures that may or may not be exempt from GWP limits under EPA's
proposed rule, including those for laboratory equipment and IPR
chillers. One commenter proposed an exemption for all IPR applications
with a refrigerant evaporating temperature below -45 [deg]C, and
suggested that all IPR systems, including both direct process cooling
and chiller systems, have the same GWP limits, as the same refrigerant
selection challenges exist for both system designs. Another commenter
suggested that EPA exempt specialty applications for systems designed
for -50 [deg]C (-58 [deg]F) exiting fluid temperatures or create a
formal variance process, similar to California and Washington State
regulations. One commenter stated that to meet the technical demands of
the laboratory products industry's specialized applications, new
sustainable substitutes--or a sudden and transformative advance in
refrigeration science--would be necessary to meet the schedule of the
proposed rule. The commenter strongly encouraged EPA to consider
providing clear, concise exceptions for equipment utilized in a
laboratory setting or provide for a longer compliance window so that
there is adequate time to make substantive changes to delicate and
complex laboratory equipment.
    Response: After review of the comments and further consideration of
the availability of substitutes under subsection (i)(4) of the AIM Act,
EPA is establishing separate GWP thresholds for IPR equipment based on
the temperature of the refrigerant entering the evaporator. This
provides more options for specialized equipment that must achieve
temperatures significantly lower than 0 [deg]F, considering
technological achievability as a factor limiting the availability of
substitutes in such equipment.
    EPA largely agrees with the commenter that asserted IPR systems
with evaporating temperatures below -25 [deg]C (-13 [deg]F) require the
same refrigerant options as chillers for IPR in which EPA proposed a
GWP limit of 700, as the same technical constraints related to
refrigerating at colder temperatures apply (e.g., fewer refrigerants
have such a low boiling point). EPA is therefore finalizing a GWP limit
of 700 for IPR equipment with refrigerant entering the evaporator with
a temperature less than -30 [deg]C (-22 [deg]F) but greater than or
equal to -50 [deg]C (-58 [deg]F), regardless of the refrigerant charge
capacity or whether the equipment is part of a cascade system.
    EPA disagrees with the comment that the threshold be at -25 [deg]C
(-13 [deg]F) because the same constraints on the availability of
substitutes under the (i)(4)(B) analysis that can be used at lower
temperatures apply in other subsectors, such as for chillers for
comfort cooling and chillers for IPR; hence, EPA is finalizing the same
GWP threshold based on the same temperature threshold as for chillers
for IPR at -30 [deg]C (-22 [deg]F). This also allows for greater
simplicity and ease of determining which GWP threshold applies than if
there were different thresholds for chillers for IPR and for other IPR
systems. One of the commenters has stated that refrigerant with an
evaporating temperature of less than -25 [deg]C should be able to use
refrigerants such as R-513A, which has a GWP of 630 (between 300 and
700). Such equipment would have the same refrigerant options as
chillers for IPR.
    EPA also disagrees that a GWP limit up to 2,200 would be
appropriate, given the sufficiently available substitutes with GWP
below 700 for use in this exiting fluid temperature range, such as R-
513A (GWP 630). Furthermore, as indicated by considerations described
in recently proposed SNAP listings for use in IPR (88 FR 33722, May 24,
2023), there may be additional available substitutes for this equipment
in the future, such as HFO-1234yf (GWP 1), HFO-1234ze(E) (GWP 1), R-
457A (GWP 137), R-516A (GWP 140), R-455A (GWP 146), R-454C (GWP 146),
and R-454A (GWP 237).
    For IPR equipment with refrigerant entering the evaporator with a
temperature of -30 [deg]C (-22 [deg]F) or higher, EPA disagrees with
the commenter who requested the Agency finalize a GWP limit as high as
700. EPA has identified HCFO-1224yd(Z) (GWP less than 1), R-717 (GWP
1), R-1270 (GWP 1.8), R-290 (GWP 3.3), and R-600 (GWP 4) as suitable
for use in equipment operating above -30 [deg]C (-22 [deg]F), and all
have a GWP below 150. In comparison, equipment with temperatures
between -30 [deg]C (-22 [deg]F) and -50 [deg]C (-58 [deg]F) could
require higher volumetric capacity (e.g., to replace R-404A) and would
have fewer refrigerants able to attain lower boiling points, so a wider
range of refrigerants with higher GWPs are needed compared to equipment
with temperatures at -30 [deg]C (-22 [deg]F) and above. EPA is
therefore finalizing the GWP limits of 150 and 300 for this type of
equipment, depending on the refrigerant charge capacity and whether the
refrigerant is used in the high temperature side of a cascade system,
based on the technological achievability of using identified
substitutes at these warmer evaporating temperatures.
    EPA disagrees with comments that requested exemptions for all IPR
systems using flooded or liquid overfed evaporators. Many of the
technological challenges associated with using lower-GWP refrigerants
in IPR equipment are related to the temperature of the refrigerant
going into the evaporator. Therefore, EPA has not set restrictions for
IPR equipment, including those using flooded or liquid overfed
evaporators, operating below -50 [deg]C (-58 [deg]F) at this time.
    In the case of IPR equipment with refrigerant temperature entering
the evaporator lower than -50 [deg]C (-58 [deg]F), EPA recognizes that
most of the refrigerants used for such equipment have relatively high
GWPs. The Agency expects that after further research and development,
there may be additional refrigerants available for these low
temperatures, given the growing demonstrations of technological
achievability; additional reviews of refrigerants for safety, health,
and environmental impacts under the SNAP program; and changes to
industry standards that allow for larger charge sizes of flammable
refrigerants, such as ethane. However, upon evaluating the availability
of substitutes for IPR equipment operating at very low temperatures,
EPA is not restricting the use of HFCs and HFC blends in new IPR
equipment with refrigerant entering the evaporator or chillers for IPR
with exiting fluid temperatures lower than -50 [deg]C (-58 [deg]F) in
this final rule. Given that this equipment is not covered in this final
rule, EPA declines to implement an individual variance process as
requested by the commenter. Note that EPA may choose to set
restrictions in the future as the availability of lower-GWP substitutes
continues to grow.