As the terms ``appliance'' and ``refrigerant-containing appliance''
are not defined terms under the AIM Act, the regulatory definition will
provide clarity as to what types of equipment would be subject to
certain proposed requirements. EPA intends this term to be a subset of
the broader category of ``equipment'' subject to subsection (h) of the
AIM Act. EPA notes that this proposed definition differs from the
definition of ``appliance'' under section 608 of the CAA. Sections 601
and 608 of the CAA specified that an appliance ``is used for household
or commercial purposes,'' and that phrase also appears in the
definition of ``appliance'' in 40 CFR 82.152. The AIM Act has no
analogous provision. Accordingly, EPA is not proposing to include that
phrase in defining ``refrigerant-containing appliance'' for purposes of
implementing subsection (h). In keeping with the application of Title
VI of the CAA (e.g., under sections 608 and 612), EPA is defining a
``refrigerant-containing appliance'' to consist of an independent
circuit. The independent circuit provides the desired cooling or
heating effect, typically consisting of a compressor, condenser,
evaporator, and metering device in an enclosed refrigerant loop. EPA
notes that a given piece of equipment could contain multiple
independent circuits and thus be considered as multiple, separate
``refrigerant-containing appliances.'' For instance, some food retail
cases have been made with multiple independent circuits, each one
containing the maximum 150-gram charge limit of propane, thus allowing
a single case to address a higher refrigeration load. Also, some
household refrigerator-freezers have been produced with two independent
circuits, one handling the refrigerator and another the freezer.
    Refrigerant-containing equipment means equipment as defined in this
subpart that contains, uses, or is otherwise connected or associated
with a regulated substance or substitute for a regulated substance that
is used as a refrigerant. This definition includes refrigerant-
containing components, refrigerant-containing appliances, and MVAC-like
appliances. This term does not include mission-critical military end
uses and systems used in deployable and expeditionary situations. This
term also does not include space vehicles as defined in 40 CFR 84.3.
    EPA is proposing to explicitly state that the definition of
``refrigerant-containing equipment'' under subsection (h) does not
include mission-critical military end uses and systems used in
deployable and expeditionary applications, as well as space vehicles.
This proposed exclusion is based on EPA's understanding that there are
situations in which the unique design and use of mission-critical
military end uses and systems used in deployable and expeditionary
situations and space vehicles make it impossible to recover refrigerant
during the service, repair, disposal, or installation of the equipment.
Likewise, requiring adherence to the leak repair and other

proposed provisions for refrigerant-containing equipment in this
proposal in an active military zone of engagement, including systems
used in deployable and expeditionary situations, could lessen the
military effectiveness of the equipment. Likewise, requiring leak
repair and other provisions in this proposal for such equipment in
space vehicles could lessen their effectiveness.
    Repackager means an entity who transfers regulated substances,
either alone or in a blend, from one container to another container
prior to sale or distribution or offer for sale or distribution. An
entity that services system cylinders for use in fire suppression
equipment and returns the same regulated substances to the same system
cylinder it was recovered from after the system cylinder is serviced is
not a repackager.
    Repair, for purposes of this subpart and as it relates to a
particular leak in a refrigerant-containing appliance, means making
adjustments or other alterations to that refrigerant-containing
appliance that have the effect of stopping leakage of refrigerant from
that particular leak.
    Reprocess means using procedures, such as filtering, drying,
distillation and other chemical procedures to remove impurities from a
regulated substance or a substitute for a regulated substance.
    Retrofit, as it relates to a refrigerant-containing appliance,
means to convert an appliance from one refrigerant to another
refrigerant. Retrofitting includes the conversion of the appliance to
achieve system compatibility with the new refrigerant and may include,
but is not limited to, changes in lubricants, gaskets, filters, driers,
valves, o-rings or appliance components. Retrofits required under this
subpart shall be done to a refrigerant with a lower global warming
potential. EPA is proposing this definition as similar to the parallel
definition in 40 CFR 82.152, with an additional provision requiring
that retrofits performed for compliance with this rulemaking must
involve switching to a lower GWP refrigerant. EPA is proposing to
include this provision as part of this definition for the purposes of
this action so that if an owner or operator chooses to retrofit a
refrigerant-containing appliance in lieu of repairing a leak, the
retrofit must use a refrigerant that is a lower GWP in the original
equipment. One implication of including this provision would be that if
there are cases in which switching to a lower GWP refrigerant is not an
option (e.g., for reasons such as safety considerations or a
refrigerant with a lower GWP is not suitable for use in a particular
refrigerant-containing appliance), a retrofit would not be available as
a compliance option for the particular refrigerant-containing
appliance. Additional detail on the requirements of performing a
retrofit and developing a retrofit plan can be found in section
IV.C.3.f. of this preamble.
    Stationary refrigerant-containing equipment means refrigerant-
containing equipment, as defined in this subpart, that is not a motor
vehicle air conditioner or MVAC-like appliance, as defined in this
subpart.
    Substitute for a regulated substance means a substance that can be
used in equipment in the same or similar applications as a regulated
substance, to serve the same or a similar purpose, including but not
limited to a substance used as a refrigerant in a refrigerant-
containing appliance or as a fire suppressant in fire suppression
equipment, provided that the substance is not a regulated substance or
an ozone-depleting substance.
    EPA is proposing for the purposes of this action to define a
substitute for a regulated substance to make clear that substitutes in
this rulemaking would not include regulated substances or ozone-
depleting substances. Examples of a substitute for a regulated
substance include but are not limited to HFOs, hydrocarbons (e.g.,
propane, isobutane), ammonia (NH4), and CO2. A
substitute for a regulated substance may be used neat or in a blend.
Subsection (h) includes authority for EPA to develop regulations
involving regulated substances and substitutes for regulated
substances. Specifically, subsection (h)(1) expressly provides that EPA
is to promulgate certain regulations involving a regulated substance, a
substitute for a regulated substance, the reclaiming of a regulated
substance as a refrigerant, or the reclaiming of a substitute for a
regulated substance as a refrigerant. EPA acknowledges that this
definition of ``substitute for a regulated substance'' differs from the
definition of the similar term, ``substitute'' \42\ in the proposed
Technology Transitions Rule (87 FR 76738, December 15, 2022). EPA is
proposing this definition for purposes of implementing subsection (h),
because specifying that substitutes for a regulated substance are only
those substances that do not contain HFCs will draw a distinction that
is helpful for certain provisions in this proposal, as EPA is proposing
to control certain practices, processes, or activities as they relate
to regulated substances differently from compared to how they relate to
substitutes for regulated substances. As EPA has noted in the Executive
Summary at section I.A., the terms ``HFC'' and ``regulated substance''
are used interchangeably in this preamble. Similarly, throughout this
preamble, EPA notes that the term ``substitute for an HFC'' may be used
interchangeably with ``substitute for a regulated substance'' in this
preamble.
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    \42\ The proposed definition for substitute in the proposed
Technology Transitions rule is: ``any substance, product, or
alternative manufacturing process, whether existing or new, that is
used, or intended for use, in a sector or subsector with a lower
global warming potential than the regulated substance, whether neat
or used in a blend, to which a use restriction would apply.'' (See
87 FR 76738, 76754, December 15, 2022). EPA further notes that it
has not made final decisions for the Technology Transitions rule.
---------------------------------------------------------------------------

    Virgin regulated substance means any regulated substance that has
not had any bona fide use in equipment except for those regulated
substances contained in the heel or the residue of a container that has
bona fide use in the servicing, repair, or installation of equipment.
    EPA is proposing to add this definition of ``virgin regulated
substance'' to make it clear that introduction of a regulated substance
to equipment, such as a refrigerant-containing appliance or fire
suppression equipment, solely to convert the regulated substance to
``used'' regulated substance in order to circumvent the intended
requirements of this proposal is not permissible. This scenario, where
regulated substance is charged to equipment, such as a refrigerant-
containing appliance or fire suppression equipment, and recovered
without any bona fide use, was brought to EPA's attention by
stakeholders including during public stakeholder meetings as the agency
developed this proposal.\43\ A regulated substance that has had no bona
fide use in equipment would be considered a virgin regulated substance
unless it was from the heel or residue of a container that did have a
bona fide use in the servicing, repair, or installation of equipment.
---------------------------------------------------------------------------

    \43\ EPA held stakeholder meetings for public input on November
9, 2022 and March 16, 2023 as well as solicited feedback through a
webinar for the EPA GreenChill Partnership program on April 12,
2023.
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B. Which sectors and subsectors is EPA considering addressing under
subsection (h)?

    Subsection (h) of the AIM Act provides EPA authority to promulgate
regulations to control, where appropriate, any practice, process, or
activity related to the servicing, repair, disposal, or installation of
equipment that involves HFCs or their substitutes, or the reclaiming of
HFCs or their substitutes used as refrigerants. EPA

interprets this provision to include authority to regulate, as
appropriate, practices, processes, or activities related to any sector,
subsector, or application where a regulated substance or a substitute
for a regulated substance is used in equipment. Regulated substances
and their substitutes are typically used in the RACHP sector as a
refrigerant in a vapor compression cycle to cool and/or dehumidify a
substance or space, like a refrigerator cabinet, room, office building,
or warehouse. Regulated substances and/or their substitutes may also be
used in other sectors, subsectors, or applications, such as aerosols,
fire suppression, solvent cleaning, foam blowing, and others. However,
as noted in section II.B. of this proposal, subsection (h)(4) expressly
provides that any rulemaking under subsection (h) shall not apply to a
regulated substance or a substitute for a regulated substance that is
contained in a foam. Thus, EPA is not proposing any requirements for
regulated substances or their substitutes when they are contained in
foams in this proposal. Accordingly, EPA interprets its authority under
subsection (h) to include promulgating regulations that control the
types of practices, processes, or activities identified in subsection
(h)(1) in any of those sectors, subsectors, or applications, with the
limitation that we do not interpret our regulatory authority under
subsection (h) to extend to HFCs or substitutes for HFCs when they are
contained in foams.
    EPA is proposing requirements for equipment in certain sectors or
subsectors as described in sections IV.C.-F. of this preamble. While
EPA interprets subsection (h) to provide authority that could be
applied to practices, processes, or activities related to equipment
across a broad range of sectors, subsectors, or applications that
involve regulated substances and/or their substitutes, at this time EPA
is focusing on certain sectors and subsectors in the requirements
proposed in the rulemaking. In future rulemakings, EPA may consider
establishing requirements for equipment in other sectors, subsectors,
or applications that involve regulated substances and/or their
substitutes. The relevant sections of this preamble describe the
requirements that EPA is proposing for equipment in certain sectors and
subsectors and how EPA understands these sectors and subsectors as
relevant for these proposed requirements.
    Where EPA is proposing requirements for certain sectors or
subsectors, we intend to be consistent with how those sectors or
subsectors are understood under other provisions of the AIM Act and/or
CAA Title VI that address the same sector or subsector, such as
subsection (i) of the AIM Act, through the Technology Transitions
program. EPA issued a proposed Technology Transition rulemaking on
December 15, 2022 (87 FR 76738) which provides additional detail on
many of the same sectors and subsectors for which we are proposing
certain requirements under subsection (h). Although EPA has not yet
made final decisions regarding those sectors or subsectors under
subsection (i) of the AIM Act, we also anticipate considering how those
sectors or subsectors are addressed in the final Technology Transitions
rulemaking in developing this rulemaking under subsection (h) of the
AIM Act.
    EPA is proposing certain provisions, as described later in this
preamble, for certain equipment in applicable subsectors within the
RACHP sector in this action. Such subsectors within the RACHP sector
include: residential and light commercial air conditioning and heat
pumps; cold storage warehouses; IPR; stand-alone retail food
refrigeration; supermarket systems; refrigerated transport; and
automatic commercial ice makers. EPA is also proposing certain
provisions for equipment in the fire suppression sector, as described
later in this preamble. Not all provisions proposed in this rulemaking
would apply to each of the sectors and subsectors identified here. For
example, EPA is proposing certain requirements for the use of reclaimed
HFCs in residential and light commercial AC and heat pumps. However,
EPA is proposing to exempt residential and light commercial AC and heat
pump equipment in the universe of refrigerant-containing appliances
subject to proposed leak repair requirements. Additional detail can be
found in section IV.C.2. of this preamble.
    EPA is requesting comment on all aspects of this proposed rule.
Where EPA is proposing requirements for equipment in certain sectors
and subsectors, EPA is providing additional detail noting specific
areas for which we are seeking comment.

C. How is EPA proposing to address leak repair?

1. Background
    As noted above, subsection (h) of the AIM Act includes provisions
focused on the management of regulated substances. Specifically,
subsection (h)(1) directs EPA, for ``purposes of maximizing reclaiming
and minimizing the release of a regulated substance from equipment and
ensuring the safety of technicians and consumers,'' to ``promulgate
regulations to control, where appropriate, any practice, process, or
activity regarding the servicing, repair, disposal, or installation of
equipment (including requiring, where appropriate, that any such
servicing, repair, disposal, or installation be performed by a trained
technician meeting minimum standards, as determined by the
Administrator) that involves'': ``a regulated substance''; ``a
substitute for a regulated substance''; ``the reclaiming of a regulated
substance used as a refrigerant''; or ``the reclaiming of a substitute
for a regulated substance used as a refrigerant.''
    Among other things, EPA interprets its regulatory authority under
subsection (h)(1) to include authority to establish requirements
related to the detection, prevention, and repair of leaks for equipment
containing HFCs or substitutes for HFCs (whether the equipment uses the
HFC or substitute for an HFC neat or in a blend with other substances).
EPA understands the statutory phrase ``regulations to control . . . any
practice, process, or activity'' as including authority for rules
governing both the manner in which a practice, process, or activity
occurs (e.g., standards that must be met, timing of the process or
activity, etc.), as well as rules requiring that a practice, process,
or activity be undertaken. Regulations establishing requirements for
leak prevention, detection, and repair would control practices,
processes, and activities regarding the servicing, repair, disposal, or
installation of equipment. For example, detecting and fixing leaks in
equipment would be considered an activity regarding the servicing or
repair of equipment. Similarly, leak prevention and/or inspection and
repair practices, processes, or activities would be conducted regarding
the servicing and/or repair of equipment.
    The requirements proposed in this rulemaking also relate to the
statutory purposes identified in subsection (h)(1). Requirements
related to the detection, inspection, repair, and prevention of leaks
for equipment containing HFCs (whether used neat or in a blend) or
their substitutes would serve the statutory purpose of minimizing the
release of regulated substances from equipment. For example, leak
detection, inspection, and repair requirements help minimize such
releases because the sooner a leak is found and repaired, the less HFC
will be released. Further, leak prevention requirements would minimize
HFC releases by avoiding potential leaks in the first place.
Additionally, regulations establishing

requirements for leak prevention, detection, and repair would also
further the statutory purpose of maximizing the reclamation of
regulated substances by reducing the amount of HFC released from
equipment and thus increasing the amount of HFC that is available to be
recovered and reclaimed. Any regulated substance used in equipment that
is released through leaks and escapes to the atmosphere reduces the
amount of HFC remaining in the equipment that could otherwise be
recovered and reclaimed for further use.
    Further, as the phasedown of the production and consumption of HFCs
as required by the AIM Act progresses, reclaimed HFCs will play a key
role in the amount of available HFCs for equipment that will continue
to use HFCs (e.g., for servicing). Reclaimed HFCs will also be
important in avoiding potential economic disruption that could be
associated with the scarcity of virgin HFCs as well as avoid stranding
existing equipment that will need to be serviced using HFCs. Generally,
overall refrigerant management in appliances helps to maintain the
health of the appliances. This can be crucial for refrigerant-
containing appliances in the RACHP subsectors that are relevant to
handling food products, such as supermarket systems, refrigerated
transport, and other food retail subsectors where the intended function
is to ensure food products are maintained at appropriate temperatures
to avoid spoilage and food waste. In 2021, 344,000 tons of food were
lost in the United States due to equipment issues in the retail and
food service subsectors.\44\ Successful repair of leaks and avoiding
leaks are a few ways to help ensure that these appliances are operating
efficiently and as intended and can help to avoid unnecessary food
waste.
---------------------------------------------------------------------------

    \44\ ReFED, Insights Engine Food Waste Monitor, May 2023,
available at: https://insights-engine.refed.org/food-waste-monitor?view=overview&year=2021.
---------------------------------------------------------------------------

    In considering requirements related to leak prevention, detection,
and repair under subsection (h) of the AIM Act, EPA further notes that
subsection (h)(3) expressly provides that EPA may coordinate
regulations promulgated to carry out subsection (h) with any other
regulations promulgated by EPA that involve the same or a similar
practice, process, or activity regarding the servicing, repair,
disposal, or installation of equipment, or reclaiming. Accordingly, the
Agency considered various potential approaches to coordinating the
proposed regulations under subsection (h) related to leak prevention,
detection, and repair with regulations previously promulgated under CAA
section 608, given they relate to the same or similar practices,
processes, or activities for refrigerant-containing appliances
containing ODS. In particular, during the development of this NPRM, EPA
considered the requirements at 40 CFR 82.157.
    As noted in the background section of this preamble at section
III.C.1., all provisions in 40 CFR part 82, subpart F except leak
repair currently apply to appliances containing ODS substitutes
including regulated HFCs used neatly or in blends. EPA is not proposing
any requirements duplicative of those in this action. However, EPA is
proposing to establish leak repair requirements for refrigerant-
containing appliances using HFCs and/or substitutes for HFCs.
    As described in the definitions section of this proposal at section
IV.A.3., EPA is proposing to define ``equipment'' as including
appliances. In the context of subsection (h), EPA considers that
appliances would be a subset within the broader category of equipment.
EPA has also proposed to define ``refrigerant-containing appliance'' in
section IV.A.3. In this action, the Agency generally refers to the
proposed leak repair requirements as applying to refrigerant-containing
appliances. In the context of the proposed leak repair requirements,
appliances are considered types of equipment that are used in
subsectors within the RACHP sector. EPA is proposing leak repair
provisions for certain refrigerant-containing appliances with a
refrigerant that contains HFCs or certain substitutes for HFCs (whether
the equipment uses the HFC or certain substitutes for an HFC neat or in
a blend with other substances) under subsection (h) of the AIM Act. If
finalized, these regulations would be codified at 40 CFR part 84.106.
2. Scope of the Proposed Leak Repair Requirements
    EPA is proposing leak repair requirements for certain refrigerant-
containing appliances containing HFC (whether used neat or in a blend)
or certain HFC substitute refrigerants under subsection (h) of the AIM
Act. These requirements are being proposed as part of implementing
subsection (h)(1) of the AIM Act, as these provisions would control
practices, processes, or activities regarding servicing or repair of
appliances, which are a type of equipment, and would involve a
regulated substance or a substitute for a regulated substance. The
requirements proposed are similar to leak repair provisions for
appliances containing an ODS refrigerant found at 40 CFR 82.157,\45\
but are not identical. In particular, EPA is proposing to apply the
leak repair requirements under subsection (h) of the AIM Act to
appliances containing HFCs or certain substitutes for HFCs with lower
charge sizes. Where EPA is proposing to require the same or similar
practice, process or activity for applicable appliances containing HFC
or substitutes for HFCs as is required under 40 CFR 82.157 for
appliances containing an ODS refrigerant, EPA is proposing to adopt
regulatory text under 40 CFR part 84, where appropriate, that is
consistent with the parallel provision in 40 CFR 82.157. Where the
proposed requirements are different, the regulatory text will differ.
---------------------------------------------------------------------------

    \45\ In this proposed rulemaking, EPA is not reopening the leak
repair requirements at 40 CFR 82.157 or proposing any changes to
them.
---------------------------------------------------------------------------

a. Appliances containing which refrigerants would be subject to the
proposed leak repair requirements?
    EPA is proposing to include HFCs (including blends that contain
HFCs) and certain substitutes for HFCs under the provisions related to
leak repair under subsection (h) of the AIM Act. As noted previously,
HFCs are potent GHGs with GWPs that can be hundreds to thousands of
times more potent than CO2. As noted in the background
section of this preamble (section III.A), global HFC use and emissions
have been increasing since the ODS phaseout and their increasing use in
RACHP equipment.\46\ Provisions related to leak repair for equipment
that use HFCs and their substitutes are critical to mitigating
emissions of HFCs and meeting the purpose stated in subsection (h)(1)
of the AIM Act to minimize releases of regulated substances from
equipment. As mentioned, the AIM Act includes a list of 18 HFCs as
regulated substances and provides authority for the Administrator to
add additional HFCs if certain criteria are met, including that the GWP
of the substance is above 53.\47\ Certain substitutes for HFCs have
GWPs that are below that of the lowest GWP of a substance that EPA
could list as a regulated substance under subsection (c)(3)(A)(i)(II)
of the AIM Act (i.e., a GWP of greater than 53). EPA is proposing to
apply the leak repair requirements to refrigerant-containing appliances
containing an HFC

refrigerant or a substitute for HFC refrigerants that have a GWP above
53 (whether the HFC or substitute for an HFC is used neat or in a
blend). EPA is proposing this cutoff for the leak repair provisions;
however, other provisions in this proposal would apply to any
substitute for an HFC without any GWP threshold, unless otherwise
specified.
---------------------------------------------------------------------------

    \46\ WMO, 2022.
    \47\ Subsection (c)(3)(A) provides the criteria by which the
Administrator may designate a substance not included in the list of
regulated substances in subsection (c)(1); these criteria include
that the substance must be a chemical substance that is a saturated
hydrofluorocarbon and have an exchange value (i.e., GWP) greater
than 53.
---------------------------------------------------------------------------

    In subsection (h) of the AIM Act, Congress directed EPA to control,
where appropriate, any practice, process, or activity regarding the
servicing, repair, disposal, or installation of equipment involving
HFCs or their substitutes. EPA is proposing that for the leak repair
provisions under subsection (h), it is appropriate at this time to only
address substitutes for HFCs (whether used neat or in a blend) with
GWPs that are greater than the cutoff Congress provided for listing new
regulated substances (i.e., a GWP of 53). The agency notes that
currently the vast majority of HFC refrigerants and refrigerant blends
containing HFCs in equipment have much higher GWPs, often 20 to 50, or
even more than 75 times as high as this cutoff. EPA acknowledges that
over time the refrigerant market is likely to shift, and that this
proposal is based on the current and near-term anticipated market for
equipment that contains HFCs and substitutes for HFCs. Thus, we view it
as appropriate to focus the proposed leak repair requirements on HFCs
and substitutes for HFCs with GWPs above 53 in this rulemaking, whether
the HFC or substitute is used neat or in a refrigerant blend. We
further note that EPA may in a future rulemaking consider establishing
leak repair requirements for substitutes for HFCs and blends containing
substitutes for HFCs with a GWP at or below 53. For example, if EPA
becomes aware of concerns related to this limitation as the refrigerant
market shifts to lower GWP substitutes for HFCs, EPA could consider
revisiting this requirement.
    To determine whether an appliance containing a substitute for a
regulated substance is required to comply with the proposed leak repair
provisions, EPA is proposing to adopt the similar process for
determining the GWP of regulated substances and/or their substitutes as
described in the proposed Technology Transitions Rule (87 FR 76738,
76750, December 15, 2022). The GWP of a regulated substance would use
the GWP as related to the exchange value listed in subsection (c) of
the AIM Act and codified as appendix A to 40 CFR part 84.\48\ For the
GWP of substitutes for regulated substances, EPA is proposing to use
IPCC's Fourth Assessment Report (AR4) 100-year GWPs wherever possible
given they are numerically the same as the exchange values in the AIM
Act and because EPA considers such an approach to be less complicated.
For hydrocarbons listed in Table 2-15 of AR4, EPA is proposing to use
the net GWP value. For substances for which no GWP is provided in AR4,
EPA is proposing to use the 100-year GWP listed in World Meteorological
Organization (WMO) 2022.\49\ For any substance not listed in either of
these sources, EPA is proposing to use the GWP of the substance in
Table A-1 to 40 CFR part 98, as it exists on a specified date, such as
the date any final rule based on this proposal is published in the
Federal Register, if such substance is specifically listed in that
table. EPA is aware of two potential substitutes for regulated
substances that might be addressed by the proposed requirements that
are not listed in these three sources, trans-dichloroethylene (HCO-
1130(E)) and HCFO-1224yd(Z) and is proposing to set these GWPs to be
five \50\ and one,\51\ respectively, for the purposes of this proposal.
For any other substance not listed in the above three source documents,
EPA is proposing that the default GWPs as shown in Table A-1 to 40 CFR
part 98, as it exists on a specified date, such as the date any final
rule based on this proposal is published in the Federal Register, shall
be used. In the event that the hierarchy outlined in this section does
not provide a GWP (i.e., the substance in question is not listed in the
three documents, is not one of the two for which EPA is proposing GWPs,
is not listed in Table A-1 to 40 CFR part 98 and does not fit within
any of the default GWPs provided in Table A-1 to 40 CFR part 98), EPA
is proposing to use a GWP of zero. In any case where a GWP value is
preceded with a less than (<), very less than (<<), greater than (>),
approximately (~), or similar symbol in the source document, which is
used to determine the GWP, EPA is proposing that the value shown shall
be used.
---------------------------------------------------------------------------

    \48\ EPA noted in section III.A. of this preamble that the
exchange values for the regulated HFCs listed in subsection (c) of
the AIM Act are numerically identical to the 100-year GWPs of each
substance, as given in the Errata to Table 2.14 of the IPCC's Fourth
Assessment Report (AR4) and Annexes A, C, and F of the Montreal
Protocol. Available at: https://www.ipcc.ch/site/assets/uploads/2018/05/ar4-wg1-errata.pdf.
    \49\ WMO, 2022.
    \50\ 81 FR 32244 (May 23, 2016).
    \51\ 84 FR 64766 (November 25, 2019).
---------------------------------------------------------------------------

    Applying the proposed provisions related to leak repair under
subsection (h) to HFC substitutes with a GWP greater than 53, but not
those with a GWP at or below 53, would result in certain lower GWP
refrigerants (e.g., single component HFO refrigerants) that are covered
by the venting prohibition at 40 CFR 82.154(a)(1) to be excluded from
coverage under the proposed subsection (h) leak repair provisions, as
they have a GWP lower than 53. The proposed leak repair requirements
would still apply where any substitute for an HFC is a component in a
refrigerant blend that contains an HFC or another substitute for an HFC
with a GWP above 53. This would be true even if one or more of the
components of the refrigerant blend is a substitute for an HFC that is
exempted from the venting prohibition under 40 CFR 82.154(a)(1). In
describing the practical effects of our proposed approach, we are not
reopening, taking comment on, or proposing to modify any regulatory
provisions in 40 CFR part 82 in this NPRM.
    In the case that a refrigerant-containing appliance uses a
refrigerant blend that contains an ODS and an HFC or a substitute for
an HFC with a GWP above 53, EPA is proposing that the owner or operator
of such appliance be required to simultaneously meet the leak repair
provisions promulgated under CAA section 608 at 40 CFR 82.157 and the
proposed provisions in this action, to the extent that they are
applicable. EPA notes that many of the provisions in this proposed
action are similar to those in 40 CFR 82.157, which should help
alleviate any concerns about duplicative requirements. However, the
provisions proposed in this NPRM (as described in the following
section) would apply to refrigerant-containing appliances with a charge
size of 15 pounds or more of a refrigerant that contains an HFC or a
substitute for an HFC with a GWP above 53. The requirements at 40 CFR
82.157 apply to appliances containing an ODS with a charge size at or
above 50 pounds. If such appliances use a refrigerant that also
contains an HFC or an HFC substitute that has a GWP above 53, they
would be required to meet the leak repair requirements proposed in this
NPRM, to ensure that the requirements applicable to the HFCs and HFC
substitutes are also met. An appliance with a charge size of 15 pounds
or greater containing a refrigerant blend that was made up of ODS and
an HFC or a substitute for an HFC with a GWP above 53 would also be
required to meet the proposed provisions in this action, as a way of
ensuring that the requirements that apply to the HFCs or certain
substitutes for HFCs contained in the equipment

are met. However, because these appliances would not meet the charge
size threshold under 40 CFR 82.157, those requirements would not apply
even though they contain ODS refrigerants.
    EPA intends for the leak repair requirements in this proposal to be
sufficiently consistent with the requirements at 40 CFR 82.157 such
that both sets of requirements could be met for refrigerant-containing
appliances that use a refrigerant blend containing an ODS and an HFC or
a substitute for an HFC with a GWP above 53 and that have full charge
of 50 or more pounds of refrigerant. EPA requests comment on whether
there is an impediment to a refrigerant containing-appliance
simultaneously complying with both sets of requirements.
    Leak repair provisions for appliances containing HFCs and certain
substitutes for HFCs as refrigerants as proposed in this document
should minimize emissions. EPA describes emission reductions in the
draft TSD titled Analysis of the Economic Impact and Benefits of the
Proposed Rule and in in section VI. of this proposal.
    EPA is requesting comment on all aspects of this proposal. In
particular, EPA is seeking comment on the use of a GWP cutoff to apply
the proposed leak repair requirements to equipment containing an HFC or
a substitute for an HFC as a refrigerant, used neat or in blends. EPA
also seeks comment on using a GWP above 53 as the cutoff, including,
for example, comments on whether EPA should consider a lower GWP
cutoff.
b. Appliances with what charge size would be subject to the proposed
leak repair requirements?
    EPA is proposing to apply the leak repair requirements under
subsection (h) of the AIM Act to refrigerant-containing appliances with
a charge size of 15 pounds or more of a refrigerant that contains an
HFC or a substitute for an HFC with a GWP above 53, with specific
exemptions. This is a lower threshold than the threshold for the leak
repair requirements established under CAA section 608, as the leak
repair provisions at 40 CFR 82.157 apply to appliances containing 50 or
more pounds of ODS refrigerant, a threshold that was established in
1993. EPA is aware of technological achievements that, in many cases,
have resulted in smaller charge sizes for cooling loads. For example,
microchannel heat exchangers are one such technology used to reduce
refrigerant charge size in equipment. Equipment using different
refrigerants may also have a lower charge size; for example, in air
conditioning equipment, the refrigerant charge size for HFC-32 is
approximately 10-20 percent less than that of R-410A.\52\ As another
example, EPA also understands that in certain cases, remodels or
expansions of supermarket systems can increase capacity while not
increasing the refrigerant charge size (i.e., effectively using a lower
refrigerant charge for a greater cooling capacity). Such a scenario
could be achieved by remodeling with display cases that operate at a
higher evaporator temperature to maintain product temperatures without
changing the intended purpose of the refrigeration system.\53\
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    \52\ Refrigeration, Air Conditioning, and Heat Pumps Technical
Options Committee 2018 Assessment Report, Technical and Economic
Assessment Panel, UNEP, February 2019. Available at: https://ozone.unep.org/sites/default/files/2019-04/RTOC-assessment-report-2018_0.pdf.
    \53\ See 80 FR 42903, July 20, 2015.
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    EPA is proposing a lower threshold because applying the
requirements to more equipment is expected to reduce HFC releases from
equipment and because avoided releases of HFCs from leaks would
increase the amount of HFCs that would be available for recovery and
reclamation. The AIM Act provides a schedule for a phasedown of HFCs,
as opposed to the phaseout directed for ODS under the CAA. Therefore,
there may be the continued introduction of HFC-containing equipment
indefinitely which is a notable difference from the CAA. As described
more fully in section II.B. of this proposal, subsection (h)(1) of the
AIM Act tasks the Agency with promulgating certain regulations, where
appropriate, for certain purposes, including minimizing the release of
regulated substances from equipment and maximizing the reclamation of
regulated substances. EPA interprets the phrase ``where appropriate''
in subsection (h)(1) to provide it discretion to reasonably determine
how the regulations under subsection (h)(1) will apply, including by
making determinations about the charge size threshold of equipment that
would be subject to the leak repair requirements. Consistent with its
statutory authority, EPA is proposing to use a lower threshold than the
50-pound threshold for ODS-containing appliances under 40 CFR 82.157
for the leak repair requirements to further serve these purposes.
    By proposing that the applicable charge size for appliances with a
refrigerant that contains an HFC or a substitute for an HFC with a GWP
greater than 53 to be 15 pounds or more of refrigerant, with certain
exemptions, the universe of affected appliances covered by the leak
repair requirements under subsection (h) would be expanded as compared
to the universe of appliances containing ODS refrigerants and subject
to the leak repair requirements provisions at 40 CFR 82.157. For
example, an applicable charge size of 15 pounds or more of a
refrigerant that contains an HFC or substitute refrigerant with a GWP
above 53 is expected to cover certain appliances in the following
subsectors which are typically below the 50-pound threshold under 40
CFR 82.157 and thus not subject to those provisions:
     Train air conditioning;
     Passenger buses (e.g., school, coach, transit, and trolley
buses); \54\
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    \54\ ``Bus'' is defined at 40 CFR 1037.801 and means ``a heavy-
duty vehicle designed to carry more than 15 passengers. Buses may
include coach buses, school buses, and urban transit buses.''
---------------------------------------------------------------------------

     Refrigerated transport--rail;
     Large retail food remote condensing units (e.g., cold
rooms in supermarkets); and
     Large commercial unitary air conditioning (e.g., a system
for a mid-sized office building).
    EPA is proposing a 15-pound or more refrigerant charge size for
appliances subject to the subsection (h) leak repair requirements based
in part on consideration of an analysis of equipment in applications
where HFCs or their substitutes are currently being used as a
refrigerant and where they are expected to be used in the coming years.
EPA conducted an analysis using the Vintaging Model to estimate stocks
of refrigerants used in equipment of varying charge sizes. The
Vintaging Model tracks the transition from ODS to substitutes including
HFCs by modeling the total pieces of equipment and average charge
sizes--which could vary over time based on vintage and the ODS or
substitute used--from five sectors to over 60 subsectors. Doing so
allows us to bin the pieces of equipment and total refrigerant in
equipment by charge size. A current snapshot of the model's estimates
of the installed stock of refrigerants that are HFCs and their
substitutes (excluding ODS refrigerants) in 2025 shows that
approximately 39 percent of refrigerants (on a weighted CO2e
basis) are used in appliances with a charge size above 50 pounds. An
additional 22 percent of installed stock are within appliances
containing between 15 and 50 pounds of refrigerant. In evaluating
potential sources where leak repair could be efficacious at reducing
releases of refrigerant from equipment and changes

in the RACHP market and aftermarket over the past few decades, EPA
finds it appropriate to propose a threshold of 15 pounds as the
applicable charge size of appliances that would need to comply with
leak repair requirements. As a general matter, EPA is proposing 15
pounds as the appropriate charge size threshold because at less than 15
pounds these appliances are significantly more likely to be
hermetically sealed and thus less prone to leak, and because appliances
with less than 15 pounds are also more likely to be replaced rather
than repaired.
    EPA assessed other refrigerant charge sizes for appliances to cover
in the proposed leak provisions. EPA is considering higher alternative
thresholds for charge sizes such as 30 pounds and 50 pounds, as well as
lower alternative thresholds, such as 5 pounds. For information on the
estimated costs and emissions reductions of the various charge size
thresholds, please refer to Appendix F of the draft TSD titled Analysis
of the Economic Impact and Benefits of the Proposed Rule in the docket
for this action. As a general matter, EPA considered the statutory
purposes in subsection (h)(1) to maximize the reclaiming and minimize
the releases of regulated substances from equipment when setting the
threshold for appliances covered for the leak repair requirements.
These purposes guided EPA's considerations in exploring different
charge sizes; however, subsection (h)(1) states for EPA to consider
promulgating regulations ``as appropriate'' to meet these purposes. EPA
notes that refrigerant-containing appliances with small charge sizes
(below 15 pounds) may be hermetically sealed and less prone to leaks.
Further, in many cases, these smaller appliances (e.g., residential
appliances like window air conditioning units) are likely to be
disposed of and replaced rather than repaired when they are found to be
malfunctioning. On the other hand, EPA described earlier in this
section the rationale for proposing the lower charge size threshold of
15 pounds as compared to a higher charge size (e.g., 30 or 50 pounds).
For example, EPA notes that with technological advances in some
refrigerant-containing appliances, similar cooling capacity can be
achieved with smaller relative charge sizes. We are proposing a charge
size threshold of 15 pounds of refrigerant for covered appliances in
this action.
    EPA is proposing to exempt from the leak repair requirements under
subsection (h) any refrigerant-containing appliance, including those
with a charge-size at or above 15 pounds, used for the residential and
light commercial air conditioning and heat pumps subsector.\55\ The
vast majority of appliances in the residential and light air
conditioning subsector typically have a charge size of less than 15
pounds; however, EPA is proposing exemptions in the case that an
appliance is used within this subsector with a charge size of 15 pounds
or more. These appliances are used in residences (but this subsector
does not include larger centrally-cooled apartment/condominium
buildings--where a chiller is likely used), and small retail and office
buildings. Since the majority of appliances in this subsector have a
refrigerant charge below the proposed 15-pound cutoff for leak repair
requirements, enforcement of those that are above a charge size of 15
pounds may be challenging or burdensome. It may not be immediately
obvious if a particular refrigerant-containing appliance has a charge
size of 15 pounds or greater without examining it more closely.
Further, the universe of affected appliances could grow unevenly if
appliances in this subsector were included, which could cause
compliance by owners and operators or servicing technicians to become
cumbersome. EPA's proposal to exempt appliances in this subsector from
the leak repair requirements would be administratively more efficient
and less burdensome for those that would be required to comply.
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    \55\ The residential and light commercial air conditioning
subsector includes equipment for cooling air in individual rooms,
single-family homes, and small commercial buildings, including both
self-contained and split systems. Self-contained systems include
some rooftop AC units (e.g., those ducted to supply conditioned air
to multiple spaces) and many types of room ACs, including packaged
terminal air conditioners (PTACs), some rooftop AC units, window AC
units, portable room AC units, and wall-mounted self-contained ACs,
designed for use in a single room. Split systems include ducted and
non-ducted mini-splits (which might also be designed for use in a
single room), multi-splits and variable refrigerant flow (VRF)
systems, and ducted unitary splits. For additional information on
the types of equipment, see EPA's website at https://www.epa.gov/snap/substitutes-residential-and-light-commercial-air-conditioning-and-heat-pumps. EPA is not proposing to codify a regulatory
definition for residential and light commercial air conditioning and
heat pumps subsector consistent with the foregoing description, but
EPA requests comment on whether such a regulatory definition would
be beneficial in resolving any perceived ambiguities.
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    The Agency is proposing to require leak repair provisions for new
and existing passenger buses,\56\ including school, coach, transit, and
trolley buses with charge-sizes at or above 15 pounds. The HD category
\57\ incorporates all motor vehicles with a gross vehicle weight rating
of 8,500 pounds or greater. Air conditioning systems used to cool
passenger compartments in these buses mainly use HFC-134a or R-
407C,\58\ and are typically manufactured as a separate unit that is
pre-charged with refrigerant and installed onto the vehicle in a
separate enclosure (e.g., roof mounted). The refrigerant charge for
these systems is also much larger than those for other MVAC systems,
typically ranging from 15 to 30 pounds. On the other hand, MVAC systems
used to cool passenger compartments in light-duty, medium-duty, HD on-
road and nonroad (off-road) vehicles are typically charged during
vehicle manufacture and the main components are connected by flexible
refrigerant lines. MVAC systems in these vehicles typically have charge
sizes ranging from one to eight pounds depending on the manufacturer
and cab size.59 60 EPA requests comments on the proposed
extension of the leak repair provisions to passenger buses. The Agency
is particularly interested in information, such as any technical
challenges, maintenance concerns, or other issues EPA should consider
regarding the repair of buses.
---------------------------------------------------------------------------

    \56\ ``Bus'' is defined at 40 CFR 1037.801 and means ``a heavy-
duty vehicle designed to carry more than 15 passengers. Buses may
include coach buses, school buses, and urban transit buses.''
    \57\ Defined at 40 CFR 86.1803-01.
    \58\ Chemours, Freon \TM\ Refrigerant for Bus and Rail Air
Conditioning; available at: https://www.freon.com/en/industries/stationary-ac-heat-pumps/public-transport-ac.
    \59\ ICF, 2016. Technical Support Document for Acceptability
Listing of HFO-1234yf for Motor Vehicle Air Conditioning in Limited
Heavy-Duty Applications. Available at: https://www.regulations.gov/document/EPA-HQ-OAR-2015-0663-0007.
    \60\ EPA, 2021. Basic Information about the Emission Standards
Reference Guide for On-road and Nonroad Vehicles and Engines.
Available at https://www.epa.gov/emission-standards-reference-guide/basic-information-about-emission-standards-reference-guide-road.
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    EPA is proposing to stagger the proposed compliance dates.
Appliances containing 50 pounds or more of a refrigerant containing an
HFC or a substitute for an HFC with a GWP above 53 would be required to
comply with the provisions on the effective date for the final rule.
Because these proposed requirements are similar to those that have been
in place for ODS-containing appliances at or above a full charge size
of 50 pounds for some time, EPA is proposing to conclude that this is
sufficient time for regulated entities to come into compliance.
Further, prior to the rescission in 2020 (85 FR 14150, March 11, 2020),
the final rulemaking under CAA section 608 in 2016 (81 FR 82272,
November 18, 2016) applied leak repair provisions for HFC-containing
appliances with a charge size of 50 pounds or greater. The 2016 CAA

section 608 Rule became effective on January 1, 2017, and the relevant
leak repair requirements for HFCs and other ODS substitutes (now
rescinded) applied as of January 1, 2019 (81 FR 82272, 82356, November
18, 2016). The 2020 CAA section 608 Rule took effect on April 10, 2020
(85 FR 14150, March 11, 2020). Thus, for over three years industry was
aware of these requirements and affected entities should have been
complying for more than one year before the requirements in the 2016
CAA section 608 Rule were rescinded. While entities that were no longer
subject to the leak repair requirements after rescission may have
chosen to no longer comply with those requirements after the rescission
took effect, those entities that were subject to the regulatory
requirements per the 2016 CAA section 608 Rule prior to rescission
would, at a minimum, be familiar with these requirements.
    For appliances with a full charge that is less than 50 pounds of
refrigerant, the Agency did not previously require leak repair and thus
we are proposing additional time. EPA is proposing one year after the
publication date of the final rule for appliances with a charge size
between 15 to 50 pounds of a refrigerant containing an HFC or a
substitute for an HFC with a GWP above 53 to allow the affected
regulated community time to familiarize themselves with the
requirements and make preparations to comply with them. For example, it
is expected that owners and operators of affected appliances with
between 15 and 50 pounds of a refrigerant containing an HFC or a
substitute for an HFC with a GWP above 53 may need time to learn about
the updated requirements; determine full charges of their appliances;
and update systems, standard operating procedures, and training
materials to best implement the requirements. Appliances with a full
charge of between 15 and 50 pounds of a refrigerant containing an HFC
or a substitute for an HFC with a GWP above 53 that are not exempted
would be expected to comply as of one year after the date of
publication for the final rule in the Federal Register. EPA understands
that some appliance owners or operators with equipment with a charge
size between 15 and 50 pounds of a refrigerant containing an HFC or a
substitute for an HFC may have already been repairing leaks.
Refrigerant-containing appliance owners or operators may choose to
repair leaks when not required, for example as a way to avoid costs
associated with continually adding refrigerant to systems or to avoid
any disruption in normal operations. However, given there was no leak
repair requirement for this equipment, EPA is unaware whether this is
true in all or even the majority of cases. Further, where unrequired
leak repair may have been occurring, it is not clear whether the
repairs were sufficient to ensure equipment was leaking below the
applicable leak rates (as established under 40 CFR 82.157) or whether
the repairs were verified and records of the repair event were kept.
Accordingly, these owners and operators may also need time to
understand the proposed requirements and develop practices and
processes for compliance.
    EPA is seeking comment on all aspects of this proposal. In
particular, the Agency is seeking comment on the proposed charge size
cutoff of 15 pounds of refrigerant for equipment that contain HFCs or
certain substitutes for HFCs. As noted previously, EPA is also
considering using different charge sizes as a threshold for the
proposed leak repair requirements for applicable refrigerant-containing
appliances, including those that are lower (e.g., 5 pounds) or higher
(e.g., 30 pounds). While EPA is proposing 15 pounds as the charge size
cutoff for the leak repair provisions, EPA continues to consider the
option of using a different charge size cutoff, such as 5 pounds, 30
pounds, or 50 pounds, and seeks comment on these considerations.
Further, EPA also seeks comment on its proposal to exempt refrigerant-
containing appliances in the residential and light commercial air
conditioning and heat pumps subsector from the leak repair
requirements. Specifically, EPA is seeking whether the scope of this
exemption is appropriate and if EPA should consider exempting
refrigerant-containing appliances in other subsectors from the proposed
leak repair requirements. While EPA is proposing that refrigerant-
containing appliances with a full charge between 15 and 50 pounds
subject to the leak repair requirements under 40 CFR part 84 would have
a compliance date of one year after the date of publication for the
final rule in the Federal Register, the Agency is considering
alternative compliance dates including January 1, 2025, or 18 months
from the date of publication of the final rule. EPA is seeking comment
on the proposed compliance dates for the proposed leak repair
requirements, and in particular, allowing additional time for
appliances with a refrigerant charge size of between 15 and 50 pounds.
In particular, EPA seeks information about activities (besides rule
familiarization and applicability determinations) that owners or
operators of refrigerant-containing appliances with a refrigerant
charge size of between 15 and 50 pounds perceive that they would need
to engage in prior to the effective date of the rule, the length of
time the commenter estimates the activity would take, and any available
information that would substantiate that estimate. For example, EPA
seeks comment on whether they would need to modify or initiate a
contractual relationship with a servicing technician firm, the length
of time that would take, and information to substantiate that estimate
if available.
3. What leak repair provisions is EPA proposing?
    EPA is proposing leak repair requirements under subsection (h) to
achieve the purposes of minimizing releases and maximizing the
reclamation of regulated substances by controlling practices,
processes, and activities related to the servicing, repair, or disposal
of equipment that contains regulated substances and/or their
substitutes (whether the regulated substance or the substitute is used
neat or in blends). These requirements are being proposed as part of
implementing subsection (h)(1) of the AIM Act, as these provisions
would control practices, processes, or activities regarding servicing
or repair of appliances, which are a type of equipment, and would
involve a regulated substance or a substitute for a regulated
substance.
    As described in section IV.C.2.a. and b., these leak repair
requirements would apply to refrigerant-containing appliances with a
charge size of 15 pounds or more where the refrigerant contains an HFC
or a substitute for an HFC with a GWP greater than 53. As noted in
section II.B., subsection (h)(3) provides that EPA may coordinate
regulations under this authority with other regulations promulgated by
the Agency that involve: ``the same or a similar practice, process, or
activity regarding the servicing, repair, disposal, or installation of
equipment; or . . . reclaiming.''
    EPA reviewed the regulations promulgated under CAA section 608
addressing the same or similar practice, processes or activities as
addressed in this proposal to consider the extent appropriate to
coordinate requirements in those regulations with those proposed in
this action. Specifically, EPA reviewed the leak repair requirements at
40 CFR 82.157, which do not apply to appliances containing HFCs or
their substitutes. The leak repair provisions under CAA section

608 contain requirements for practices, processes, and activities
related to identifying and repairing leaks in appliances that contain
ODS. These practices, processes, and activities are applicable to
appliances containing HFCs as, in many cases, the same types of
appliances (e.g., chillers, rooftop air conditioning units, supermarket
systems, etc.) are used since HFCs are a substitute for ODS. EPA is not
proposing new requirements in this action where the provisions in 40
CFR part 82, subpart F already apply to appliances containing HFCs and
certain substitutes. EPA notes that there are existing recordkeeping
requirements 40 CFR 82.156(a)(3) for technicians evacuating refrigerant
from appliances with a full charge of more than 5 and less than 50
pounds of refrigerant for purposes of disposal of that appliance. EPA
is not reopening any of the provisions in 40 CFR part 82 in this
action, and thus, the Agency is not proposing any changes to the
referenced recordkeeping requirements. Further, the Agency does not
view these recordkeeping requirements as being in conflict with the
proposed leak repair requirements nor does the Agency view them as
redundant. EPA notes that the bulk of the appliances covered by the
recordkeeping requirements at 40 CFR 82.156(a)(3) are residential air
conditioning appliances, which would be exempt from the proposed leak
repair provisions in this proposed action. These records are used to
assess technicians' compliance with the disposal requirements for 5 to
50 pound appliances under 40 CFR part 82 subpart F and are not related
to the owner/operator's compliance with the leak repair requirements.
    As described in greater detail in the following sections, the
proposed leak repair provisions would require action if an appliance
has been found to be leaking above the applicable leak rate threshold.
The proposed leak repair provisions would generally not necessitate any
specific action for appliances that are not leaking above the
applicable leak-rate threshold, although the leak rate calculations and
certain recordkeeping requirements would apply to appliances that are
not leaking above the threshold. While EPA is proposing to adopt the
same applicable leak rates for the leak repair requirements under
subsection (h) as applies under 40 CFR 82.157, as described in section
IV.C.3.b. of this preamble, EPA is proposing requirements for
identifying and potentially repairing leaks sooner (see section IV.C.4.
of this preamble for proposed requirements for ALD systems).
a. Leak Rate Calculations
    EPA is proposing to adopt requirements for leak rate calculations
as part of the proposed leak repair requirements under subsection (h).
Under these proposed requirements, refrigerant-containing appliances
with a charge size of 15 pounds or more of a refrigerant that contains
an HFC or a substitute for and HFC with a GWP above 53 would require a
leak rate calculation, if the appliance is found to be leaking.
Accordingly, under subsection (h), EPA is proposing to require that the
leak rate of covered appliances be calculated every time refrigerant is
added to an appliance, unless the addition is made immediately
following a retrofit, installation of a new appliance, or qualifies as
a seasonal variance, as described in this and subsequent sections.
    In this action, EPA is not proposing to require the repair of all
leaks, but rather to require repair of leaks such that the appliance is
below the applicable leak rate threshold. Thus, calculation of the leak
rate is necessary to determine where further action (i.e., repair) is
required, since owners or operators may not be able to determine
compliance without calculating the leak rate each time refrigerant is
added to the appliance. For example, if an appliance owner adds
refrigerant to the appliance but does not calculate the leak rate, the
owner would have no means of determining if the appliance's leak rate
was below the applicable leak rate threshold. Hence, the owner would
not know if further action was warranted. The leak rate calculation is
an important step for owners and operators to determine if a leak must
be repaired and to the applicable leak rate threshold to which it would
need to be repaired (as discussed in section IV.C.3.b). EPA considers
that the leak rate calculation provisions under 40 CFR 82.157(b) are
appropriate for the refrigerant-containing appliances proposed in this
action and is proposing to establish analogous requirements for
equipment covered under the subsection (h) leak repair provisions.
    EPA is proposing two methods for calculating the leak rate for an
applicable appliance under subsection (h) in this action: the
annualizing method and the rolling average method. These leak rate
calculation methods are described in section IV.A.1. This approach of
providing two different methods for calculating the leak rate, as well
as the specific leak rate calculation methods proposed, are the same as
those described and provided in 40 CFR part 82, subpart F. EPA is
proposing that these two methods could be used similarly to how they
can be used under subpart F. Based on EPA's experience under subpart F,
there are advantages in the flexibility provided by having two
different methods. The strength of the annualizing method is that it is
future oriented and allows the owner or operator to ``close out'' each
leak event so long as the requirements are followed and does not lump
past leak events with the current leak event. It considers the amount
of time since the last refrigerant addition and then scales that up to
provide a leak rate that projects the amount of refrigerant lost over a
whole year if the leak is not fixed. As a result, this formula will
yield a higher leak rate for smaller leaks if the amount of time since
the last repair was shorter. This approach can contribute to minimizing
the releases of HFCs or their substitutes by requiring more thorough
leak inspections and verified repairs sooner. The rolling average
method also has its strengths. It accounts for all refrigerant
additions over the past 365 days or since the last successful follow-up
verification test showing that all identified leaks were successfully
repaired (if less than 365 days). If an owner or operator verifies all
identified leaks are repaired, this method would also allow an owner or
operator to ``close out'' a leak event. If there is no follow-up
verification test showing that all identified leaks were successfully
repaired within the last year, the leak rate would be based completely
on actual leaks in the past year. This retrospective approach measures
actual performance and if leaks are identified and fixed quickly, an
appliance may never reach the applicable leak rate, thus limiting and
minimizing the releases of HFCs or their substitutes from leaks.
    In the 2016 CAA section 608 Rule (81 FR 82272, November 18, 2016),
EPA finalized that the same leak rate calculation must be used for all
appliances at the same facility for appliances subject to the CAA leak
repair provisions. EPA is proposing to similarly require that the same
method of leak rate calculation be used for all refrigerant-containing
appliances at the same facility for appliances subject to the proposed
leak repair provisions in this action. This aspect of the proposal
helps ensure that the requirements are followed consistently at a
facility. As noted above, having the option to choose between one of
two methodologies to calculate the leak rate

provides flexibility to the owners and operators of affected
refrigerant-containing appliances. However, once a method is chosen, it
is necessary for the owner or operator to continue using the same
methodologies so leak rates are consistently calculated for the
appliances. The two methods use two different paradigms to determine
leak rate--one is forward-looking/predictive, while the other is
looking back/retrospective. If an owner or operator were to switch
between methods, they would not get an accurate calculation (because
the time frame being evaluated would be different in each method).
    In either methodology of calculating the leak rate, EPA is
proposing that when calculating the leak rate, any purged refrigerant
that is destroyed would not be counted towards the leak rate. To
qualify for this exemption, the purged refrigerant would be required to
be destroyed at a verifiable destruction efficiency of 98 percent or
greater.
    EPA is seeking comment on all aspects of its proposal related to
leak rate calculations under subsection (h). EPA is particularly
requesting comment on if there are any alternative leak rate
calculations that could be conducted to identify whether a system is
leaking above the applicable trigger leak rate. EPA is also requesting
comment on calculating the amount of refrigerant lost, without having
to add refrigerant, as a means of calculating the leak rate. For
example, an owner or operator could evacuate all of the refrigerant
from an appliance, weigh it, and compare it to the full charge of the
appliance. Alternatively, EPA is aware that certain types of ALD
systems can infer the amount of refrigerant that has leaked from an
appliance based on operating characteristics (more detail in section
IV.C.4. of this preamble) and EPA is seeking comment on the feasibility
and technical accuracy of using the amount of refrigerant that such a
system identifies as having been lost from the appliance in the leak
rate calculation, as a means of identifying the leak rate.
b. Requirement To Repair Leaks, Timing and Applicable Leak Rates
    EPA is proposing to establish a number of requirements related to
the repair of leaks under subsection (h) related to determining when a
leak needs to be repaired, the extent of the repair required, and the
timing of such repairs. EPA is proposing to establish timing
requirements for the repair of leaks in refrigerant-containing
appliances with a charge size of 15 pounds or more with a refrigerant
that contains an HFC or a substitute for an HFC with a GWP above 53.
Under this proposal, owners or operators would be required to identify
and repair leaks within 30 days (or 120 days if an industrial process
shutdown is required) of when refrigerant is added to an appliance that
has exceeded the applicable leak rate. These proposed timing
requirements are consistent with those requirements found at 40 CFR
82.157(d) to repair leaks for ODS-containing equipment. Repairing leaks
in a timely manner helps serve the purposes identified in subsection
(h)(1). For example, timely repair is critical to reducing the
emissions of refrigerants from leaking appliances, and thus to
minimizing releases of HFCs from equipment. In addition, by repairing
leaks in a timely manner, additional HFC refrigerant will be
subsequently available for reclamation, which supports maximizing
reclaiming of HFCs. Also, equipment that is in good repair, is better
able to operate in an efficient manner.
    In some unforeseen circumstances, repair of leaks may require
additional time beyond that of the proposed timeframe. EPA is proposing
that extensions may be available for owners or operators to repair
leaks if certain conditions are met, which would further serve the
purposes identified in subsection (h)(1) of ensuring the safety of
technicians and/or minimizing the release of regulated substances.
Among these conditions, EPA is proposing that one or more must be met
to qualify for additional time. Extensions for the leak repair would be
available if the appliance is located in an area subject to
radiological contamination or shutting down the appliance will directly
lead to radiological contamination. EPA is proposing that in this case,
additional time would be permitted to the extent necessary to complete
the repairs in a safe working environment. An extension would also be
available to owners or operators if the requirements of any other
Federal, state, local, or Tribal regulations would make a repair within
30 days (or 120 days if an industrial process shutdown is required)
impossible. Additional time would be permitted to the extent needed to
comply with the applicable regulations. EPA is also proposing there
would be extensions available if components must be replaced as a part
of the repair and they are not available within the leak repair
timeframe of 30 days (or 120 days if an industrial process shutdown is
required). In this case, additional time would be permitted of up to 30
days after receiving the needed component, and the total extension
could not exceed 180 days (or 270 days if an industrial process
shutdown is required) from the date of the appliance exceeded the
applicable leak rate. In all cases of potential extensions to the leak
repair timeframe, an owner or operator would still be required to
repair leaks that the technician has identified as significantly
contributing to the exceedance of the applicable leak rate and that do
not require additional time and verify those repairs within the initial
30 days (or 120 days if an industrial process shutdown is required).
Owners or operators would also be required to document all repair
efforts and provide a reason for the inability to repair the leak
within the initial 30-day (or 120-day if an industrial process shutdown
is required) time period. All extension requests must be submitted
electronically in a format specified by EPA and include pertinent
information as described in the proposed regulatory text at Sec.
84.106.
    EPA is proposing that a leak is presumed to be repaired if there is
no further addition of refrigerant to the equipment for 12 months after
the repair or if there are no leaks identified by either the required
periodic leak inspection(s) or an ALD system, where applicable. Further
information on the proposed requirements for ALD systems are described
in section IV.C.4. While EPA is proposing to require ALD systems for
certain equipment, there may be some cases where an owner or operator
chooses to use ALD systems for equipment where it is not required.
Whether use of the ALD system is due to requirements as proposed in
section IV.C.4. or used as a compliance option in lieu of leak
inspections (see section IV.C.3.d.) for a specific appliance, if the
ALD system detects a leak in the 12-month period after a successful
leak repair, the leak repair would be presumed to have subsequently
failed unless the owner or operator can document that the ALD system
leak detection was due to a new leak unrelated to the previously
repaired leak. Such documentation would include but not be limited to
the records required to be kept under proposed 40 CFR 84.108(i).
Additional information on leak inspections is described in section
IV.C.3.d. If an appliance is mothballed, EPA is proposing that the
timeframe for repair, inspections, and verification tests would be
temporarily suspended and resume when additional refrigerant is added
to the appliance (or component of an appliance is the leaking component
was isolated).
    As noted earlier, under the CAA section 608 implementing
regulations at 40 CFR 82.157, specific leak rates are

used to determine whether a repair is needed for an appliance and also
the degree to which the leak must be repaired, as leaks must be
repaired if the appliance exceeds the applicable leak rate (which
varies depending on the type of appliance) and must be repaired such
that the leak rate is brought below the applicable leak rate. See 40
CFR 82.157(c) and (d). For the leak repair requirements under
subsection (h), EPA is proposing to use a similar approach for
determining when leaks must be repaired and the degree to which they
must be repaired. EPA is also proposing to apply the same applicable
leak rates for certain types of refrigerant-containing appliances
covered in this proposal that contain HFCs or their substitutes as
would apply to the same types of appliances under 40 CFR 82.157(c) if
it contained an ODS refrigerant. Thus, EPA is proposing that the
applicable leak rates for refrigerant-containing appliances with a
charge size of 15 pounds or more with a refrigerant that contains an
HFC or a substitute for an HFC with a GWP above 53 would be as follows:
     20 percent leak rate for commercial refrigeration
equipment;
     30 percent leak rate for IPR equipment; and
     10 percent leak rate for comfort cooling appliances or
other refrigerant-containing appliances not covered as commercial or
industrial refrigeration equipment.
    EPA is proposing that these applicable leak rates per the type of
appliance are appropriate for the proposed leak repair provisions in
this action under subsection (h) of the AIM Act. The applicable leak
rates were established to limit and minimize the releases of ODS
refrigerant and were updated to be more stringent in the 2016 CAA
section 608 Rule (81 FR 82272, November 18, 2016). EPA is proposing to
adopt applicable leak rates that mirror those that are currently in
effect for ODS-containing appliances under the 2016 CAA section 608
Rule. These rates were in effect for appliances containing 50 or more
lbs of HFCs for a period of time, and, after reviewing the information
and analysis that supported application of these leak rates to that HFC
equipment, EPA has determined it is appropriate to propose them in this
action. These applicable leak rates are relevant for minimizing
releases of HFCs from refrigerant-containing appliances that contain
HFCs. This proposal draws on EPA's experience implementing similar
requirements under section 608, where these thresholds have provided a
practical and effective method for determining when leaks must be
repaired. EPA notes in support of the 2016 CAA section 608 Rule, EPA
reviewed data from the lowest-emitting equipment to gauge technological
feasibility and then reviewed other datasets.\61\ The Agency considered
whether a lower percent leak rate for some, or all of the categories of
appliances would be more appropriate to propose in this rulemaking for
those that use refrigerants that contain HFCs and/or substitutes for
HFCs. EPA notes that, as a general matter, equipment in good repair is
typically able to operate more efficiently. EPA reviewed the docket for
the 2016 CAA section 608 Rule, which lowered the applicable leak rates
for each of the appliance categories.62 63 In that action,
EPA evaluated leak rate data of appliances in each of the applicable
categories to determine the appropriate applicable leak rates. EPA also
reviewed information from stakeholders shared during public meetings
held in the development of this proposal.\64\ EPA is proposing to use
the same applicable leak rates for each category of appliances as found
under 40 CFR 82.157. While EPA is not proposing changes to the
applicable leak rates for categories of refrigerant-containing
appliances as they involve HFCs and covered substitutes for HFCs, the
Agency notes that we could revisit the applicable leak rates as
appropriate to support the overall purposes of subsection (h) of the
AIM Act.
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    \61\ For more details on this analysis see 81 FR 82272, 82317;
Technical Support Document: Analysis of the Economic Impact and
Benefits of Final Revisions to the National Recycling and Emission
Reduction Program, September 2, 2016, available at https://www.regulations.gov/document/EPA-HQ-OAR-2015-0453-0225.
    \62\ Docket No. EPA-HQ-OAR-2015-0453.
    \63\ For further information, please see the discussion in the
2016 CAA section 608 rule at 81 FR 82272, 82317 and the technical
support document, Analysis of the Economic Impact and Benefits of
Final Revisions to the National Recycling and Emission Reduction
Program, available in the docket for the 2016 CAA section 608
rulemaking (EPA-HQ-OAR-2015-0453).
    \64\ EPA held stakeholder meetings for public input on November
9, 2022 and March 16, 2023 as well as solicited feedback through a
webinar for the EPA GreenChill Partnership program on April 12,
2023.
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    This proposal includes refrigerant-containing appliances with
charge sizes that are below the 50-pound charge size threshold for ODS-
containing appliances under 40 CFR 82.157. As discussed in section
IV.C.2., EPA is proposing to apply leak repair requirements to
appliances using an HFC and/or a substitute for HFCs as a refrigerant
(neat or in blends) based on a charge size threshold of 15 pounds or
greater, with certain exceptions as discussed in section IV.C.2.a.
above. EPA is proposing to use the same leak rate across categories of
equipment for all covered appliances. In other words, a 20 percent leak
trigger rate would apply for commercial refrigeration equipment with a
full charge size of 15 pounds or more, and a 10 percent trigger leak
rate would apply for comfort cooling appliances with a full charge size
of 15 pounds or more.
    Refrigerant-containing appliances with 15-50 pounds of refrigerant
in the applicable subsectors are proposed to be covered by the
appropriate listed categories and with the applicable trigger leak
rates. For refrigerant-containing appliances in certain subsectors and
applications that have not been previously covered under 40 CFR 82.157,
as noted in section IV.C.2.b., EPA is proposing determinations for the
applicable leak rates. For refrigerated transport--rail, EPA is
proposing that this application would be considered under the comfort
cooling and other appliances category and have an applicable leak rate
of 10 percent.
    EPA is seeking comment on all aspects of this proposal and in
particular on the proposed applicable leak rates for appliances in the
subsectors and applications noted in section IV.C.2.b. of this
proposal. EPA is also seeking comment on its proposal to include an
explicit presumption that a leak is presumed to be repaired if one of
the listed conditions is met, such as there being no further addition
of refrigerant to the equipment for 12 months after the repair. While a
similar, though not identical, presumption is included in similar
regulations under section 608 of the CAA, EPA is also proposing to
include a definition of ``repair'' to the regulatory provisions under
subsection (h), which is not a defined term in the regulations under
CAA section 608. EPA is particularly interested in comments on whether
the presumption is necessary or helpful, if the proposed definition of
``repair'' is finalized.
c. Verification Testing
    EPA is proposing requirements for initial and follow-up
verification for refrigerant-containing appliances with a charge size
of 15 pounds or more of a refrigerant that contains an HFC or a
substitute for an HFC with a GWP above 53 as a part of the proposed
leak repair provisions under subsection (h). Verification testing
involves important practices, processes, and activities regarding the
repair and servicing of equipment. The tests are performed shortly
after an appliance has been

repaired to confirm that the leak has been successfully repaired.
Without the verification tests, it may take additional time for the
owner or operator to realize that the repair has been unsuccessful and
during that time refrigerant could continue to leak from the appliance.
EPA is proposing that the verification tests must be performed for all
leak repairs to ensure that the leak repair is done correctly the first
time, which would help minimize any releases of HFCs from the
appliance, and also help maximize HFCs available for eventual
reclamation by limiting such releases.
    Thus, as part of the proposed requirements for leak repair
verification tests under subsection (h), an owner or operator would be
required to conduct initial and follow-up verification tests within
specified timeframes on each leak that is repaired. The initial
verification test would be required to be performed within 30 days (or
120 days if an industrial process shutdown is required) of an appliance
exceeding the applicable leak rate and must demonstrate that leaks are
repaired, where a repair attempt was made. The initial verification
test is to verify that the leak has been repaired prior to adding
refrigerant back into the appliance and the follow-up verification test
confirms that the repair held after refrigerant has been added and the
appliance has been brought back to normal operating characteristics.
The follow-up verification test would be required to be conducted
within 10 days of a successful initial verification test or 10 days
after the appliance has returned to normal operating conditions (if the
appliance or isolated component of the appliance was evacuated to
perform repairs). EPA is proposing that the follow-up verification test
is necessary to confirm that the leak repair has held after the
refrigerant-containing appliance has been recharged, pressurized, and
returned to normal operating conditions. Thus, these provisions are
proposed in this action to ensure leaks are properly repaired and to
ensure emissions are minimized. EPA also notes that this process of
performing an initial verification test and a follow-up verification
test has been a part of the similar leak repair provisions for affected
ODS-containing equipment under CAA section 608. For additional
discussion on the terminology, timing, and purposes associated with the
verification tests in detail in the context of the requirements under
CAA section 608, please refer to the 2016 CAA section 608 Rule (81 FR
82272, 82324, November 18, 2016).
    EPA is also considering that in some cases, a follow-up
verification test is impossible; for example, when it would be unsafe
to be present when the system is at normal operating characteristics
and conditions. Under subsection (h), EPA is proposing language to
address such situations. This approach helps serve the purpose
identified in subsection (h)(1) of ensuring technician and consumer
safety. EPA is proposing that where it is unsafe to be present or
otherwise impossible to conduct a follow-up verification test when it
would be unsafe to be present when the system is at normal operating
characteristics and conditions the follow-up verification test must,
where practicable, be conducted prior to the system returning to normal
operating characteristics and conditions. In such situations, the owner
or operator has the burden of showing that it was unsafe to be present
when the system is at normal operating characteristics and conditions.
EPA requests comment on whether there should be a recordkeeping
requirement associated with establishing that it is unsafe to be
present or otherwise impossible to conduct a follow-up verification
test on the system has been returned to normal operating conditions.
    EPA understands these initial and follow-up verification tests
after an attempted repair of a leak as involving important practices,
processes, and activities regarding the repair of equipment within the
proposed leak repair provisions. These proposed requirements are
designed to help ensure that leaks are repaired successfully and that
the repair holds, so that repair has the intended effect of limiting
emissions of HFCs or substitutes for HFCs from the appliance. EPA is
proposing that if the initial or follow-up verification test indicates
that a leak repair had not been successful, the owner or operator may
conduct as many additional repairs and initial or follow-up
verification tests as needed to achieve a successful leak repair within
the applicable time period and to verify the repairs.
    EPA is requesting comment on all aspects of this rulemaking. In
particular, EPA is requesting comment on the applicable leak rates for
each category for refrigerant-containing appliances. EPA is also
requesting comment on the timing by which the initial and follow-up
verification tests must be performed as a part of the proposed leak
repair provisions.
d. Leak Inspections
    EPA is proposing requirements for leak inspections as a part of the
proposed leak repair requirements under subsection (h). These leak
inspection requirements would apply to refrigerant-containing
appliances that have been found to be leaking at a rate that exceeds
the applicable leak rate per the appliance type. In particular, the
proposed leak inspection requirements involve processes, practices, and
activities regarding the repair of refrigerant-containing appliances
that are designed to ensure the long-term effectiveness of a successful
leak repair. Thus, the proposed requirements would help minimize any
releases of HFCs from equipment over time and also help maximize HFCs
available for eventual reclamation by limiting such releases.
    EPA is proposing that leak inspections would be required for
refrigerant-containing appliances with a charge size of 15 pounds or
more of a refrigerant that contains an HFC or a substitute for an HFC
with a GWP greater than 53 that are found to be leaking above the
applicable leak rate and have had one or more leaks repaired. Leak
inspection frequency would be dependent on the type of appliance and
the size of the appliance (by refrigerant charge size). As described in
greater detail later in this section, an ALD system that is being used
to monitor an appliance or portions of an appliance may be used as a
compliance option in lieu of quarterly or annual leak inspections,
whether the ALD system is required to be used under requirements in
this proposal or the ALD system is used voluntarily on an appliance
where it would not be required under this proposal. Where an ALD system
is not being used on an appliance or on portions of an appliance, all
leak inspection requirements proposed would be required for the
appliance or the portions of the appliance that are not being monitored
by an ALD system. If an ALD system is being used to comply with the
leak inspection requirements for an appliance or portions of an
appliance (per proposed regulatory requirement or voluntarily), certain
regulatory requirements must be met as proposed (see section IV.C.4.).
    For commercial refrigeration and IPR appliances that have a charge
size of 500 pounds or more of a refrigerant that contains an HFC or a
substitute for an HFC with a GWP greater than 53, EPA is proposing that
leak inspections be performed every three months after the equipment is
found to be leaking above the applicable leak rate until the owner or
operator can demonstrate that the equipment has not exceeded the
applicable leak rate for four consecutive quarters. For commercial
refrigeration and IPR appliances that have a charge size between 15 and
500 pounds of a

refrigerant that contains an HFC or a substitute for an HFC with a GWP
greater than 53, EPA is proposing that leak inspections be performed
once per calendar year after the equipment is found to be leaking above
the applicable leak rate until the owner or operator can demonstrate
that the equipment has not exceeded the applicable leak rate for one
year (i.e., 12 months). For comfort cooling and other appliances that
have a charge size of 15 pounds or above of a refrigerant that contains
an HFC or a substitute for an HFC with a GWP above 53, EPA is proposing
that leak inspections be performed once per calendar year after the
equipment is found to be leaking above the applicable leak rate until
the owner or operator can demonstrate that the equipment has not
exceeded the applicable leak rate for one year (i.e., 12 months). In
each case, to demonstrate that the equipment has not exceeded the
applicable leak rate, a leak rate calculation is done during a leak
inspection as described in section IV.C.3.a. of this proposal. EPA is
proposing that it is appropriate to require more frequent leak
inspections for larger commercial refrigeration and IPR appliances
(i.e., charge sizes at or above 500 pounds), as the larger charge size
means that potential emissions from the appliance are greater if a leak
is not properly repaired.
    In this action, EPA is also separately proposing requirements for
the use of ALD systems for commercial refrigeration and IPR appliances
that have a charge size of 1,500 pounds or more of refrigerant that
contains an HFC or a substitute for an HFC with a GWP above 53 (see
section IV.C.4. of this proposal). Where ALD systems would be required
to monitor leaks in appliances, EPA is proposing that leak inspections
for the appliances would be required after exceeding the applicable
leak rate and undergoing a repair only for the portions of the
appliance that are not being monitored by the ALD system (e.g., if part
of the appliance is not in an enclosed space). This proposal is based
on an understanding that where the ALD system is monitoring the
appliance, it serves the function of monitoring for leaks. Thus, a
requirement for performing periodic leak inspections on those portions
of the appliance would be unneeded. EPA considers the leak inspections
that are proposed for codification at 40 CFR 84.106(g) and the
requirements related to ALD systems that are proposed for codification
at 40 CFR 84.108 to be separate. That is to say, EPA would be proposing
these leak inspections irrespective of any mandatory ALD system
requirement and vice versa. However, recognizing that some equipment
could be subject to both requirements, if both proposals are finalized,
to help coordinate the requirements, EPA is proposing a limited
exception to the quarterly and annual leak inspection requirements if
ALD systems are being used and meet certain requirements. This proposed
limited exception is intended to allow the use of the ALD system in
those circumstances to serve as a compliance option for the leak
inspection requirement.
    For further information and requirements related to ALD systems
proposed in this action, refer to section IV.C.4. Likewise, EPA is
proposing that if an owner or operator is voluntarily using an ALD
system to monitor leaks in a refrigerant-containing appliance that
would not be subject to the proposed requirement to use an ALD system
(e.g., the equipment has a charge size below 1,500 pounds), any
periodic leak inspections would only need to be performed after the
applicable leak rate is exceeded for the portions of the appliance
where the ALD system is not monitoring for leaks. Again, where the ALD
system is monitoring the appliance, it would serve the function of
monitoring for leaks in the equipment, and periodic inspections on
those portions of the equipment would be unneeded. EPA is also
proposing that, where an appliance exceeds the applicable leak rate, an
owner or operator may choose to use an ALD system, where not required
under proposed requirements in section IV.C.4. (i.e., for certain
appliances with a charge size below 1,500 pounds), as a compliance
option in lieu of the proposed requirements for periodic leak
inspections. However, leak inspections would need to be performed for
the portions of the appliance where the ALD system is not monitoring
for leaks. Where an owner/operator wishes to use an ALD system in lieu
of proposed regulatorily required leak inspections, the ALD system
needs to meet the requirements established elsewhere in this proposal
(including annual ALD system audit and calibration requirements). The
owner or operator would be required to follow certain reporting and
recordkeeping requirements to show the ALD system is meeting the
intended functionality and monitoring leaks effectively (as described
in section IV.C.4.b.).
    EPA is requesting comment on all aspects of this proposal. In
particular, EPA is seeking comment on the proposed requirements for
leak inspection. EPA welcomes comment on the frequency of leak
inspections required based on the charge size of the equipment as well
as the use of ALD system (whether required as part of this proposal or
not) to satisfy the requirements for leak inspections.
e. Chronically Leaking Appliances
    As part of the proposed leak repair provisions under subsection
(h), EPA is proposing to include specific requirements for refrigerant-
containing appliances with a charge size of 15 pounds or more of a
refrigerant that contains an HFC or a substitute for an HFC with a GWP
above 53 that EPA would consider as chronically leaking. The proposed
requirements are designed to gather information and support efforts to
address such chronic leaks, which would have the effect of further
minimizing emissions from equipment.
    As discussed in section IV.C.2. above, under this proposal, covered
appliances include refrigerant-containing appliances with charge sizes
of 15 pounds or more of a refrigerant that contains an HFC or a
substitute for an HFC with a GWP above 53. EPA is proposing that an
appliance would be considered a chronically leaking appliance if the
appliance leaks 125 percent or more of its full charge within a
calendar year. The proposed requirements for chronically leaking
appliances are similar, but not identical to, analogous requirements
under 82.157(j). For such chronically leaking appliances, owners and
operators are required to submit reports describing the efforts taken
to identify leaks and repair the appliance. Under subsection (h), EPA
is proposing to establish a reporting requirement for covered
appliances that are considered chronically leaking.
    To better serve the purposes of minimizing releases of regulated
substances and allow EPA to more easily verify the information being
reported, EPA is proposing to standardize the reporting format for
chronically leaking appliances. EPA is proposing that the reports must
be submitted no later than March 1 following the calendar year of the
>=125 percent leak. EPA is proposing that these reports cover basic
identification information (i.e., owner name, facility name, facility
address where appliance is located, and appliance ID or description),
appliance type (comfort cooling, IPR, or commercial refrigeration),
refrigerant type, full charge of appliance (pounds), annual percent
refrigerant loss, dates of refrigerant addition, amounts of refrigerant
added, date of last successful

follow-up verification test, explanation of cause of refrigerant
losses, repair actions taken, and whether a retrofit or retirement plan
been developed for the appliance, and, if so, the anticipated date of
retrofit or retirement. EPA proposes that these reports be submitted
electronically in a format specified by EPA. EPA anticipates that the
information in these reports would either be contained in the records
EPA is proposing that owner or operators would be required to maintain,
or they are the type of information that would be on hand during the
ordinary course of business. Because of the amount of refrigerant
emitted, chronically leaking appliances warrant special attention.
These reporting requirements for chronically leaking equipment are
designed to help ensure that owner or operators are complying with the
leak repair provisions and that they have taken appropriate steps to
identify the leaks and correct the root cause of those leaks. These
reports would allow EPA to evaluate compliance with the regulatory
requirements and to identify entities that may benefit from compliance
assistance and other outreach efforts. These reports would also allow
EPA to assess common root causes for appliances that chronically leak,
which would facilitate consideration of approaches to mitigate these
leaks and minimize the releases of HFCs from such equipment. EPA
discusses whether this information is entitled to confidential
treatment in section V.A.1. of this document.
    EPA is proposing to set the reporting threshold for appliances that
leak 125 percent of the full charge within a calendar year, as the
Agency intends to avoid capturing refrigerant-containing appliances
affected by unavoidable losses of full charge. In order to be subject
to the requirement, appliances would have to lose their full charge and
then a significant quantity more within a single calendar year. EPA
requests comment on the 125 percent threshold and whether, given the
focus of minimizing releases of regulated substances, that threshold
should be lowered. For example, EPA is considering lowering the
threshold to 110 percent to avoid capturing refrigerant-containing
appliances affected by unavoidable losses of full charge, but a lower
amount leaked beyond a full charge would be required to trigger the
provisions for chronically leaking appliances.
f. Retrofit and Retirement Plans
    EPA is proposing to include requirements for retrofit and
retirement plans in the proposed leak repair provisions under
subsection (h) for applicable refrigerant-containing appliances that
contain HFCs or certain substitutes for HFCs as a refrigerant. These
requirements reduce emissions by capping the amount of time an
appliance can remain in operation when it is known to be leaking above
the leak rate threshold. Owners or operators may choose to retrofit or
retire a leaking appliance rather than repair a leak, or, in some
situations, may be required to retrofit or retire the appliance if
successful leak repair cannot be achieved and verified. The proposed
requirements would also further serve the purposes of minimizing
releases and maximizing the reclaiming of HFCs, as proper retrofit or
retirement of a leaking appliance would ensure that any further HFC
emissions from such equipment are mitigated. Additionally, in the
process of retrofitting or retiring an appliance, the refrigerant that
was remaining in the leaking appliance would typically be recovered and
could then subsequently be reclaimed.
    EPA is proposing requirements for developing retrofit and
retirement plans for refrigerant-containing appliances where leaks
cannot be repaired, or an owner or operator chooses to retrofit to a
lower GWP refrigerant (where available) or retire an appliance rather
than repair a leak. The proposed requirements would apply to
refrigerant-containing appliances with 15 pounds or more of a
refrigerant that contains an HFC or a substitute for an HFC with a GWP
above 53. The provisions proposed in this action would provide the
details on the timing for creating a retrofit or retirement plan for
covered refrigerant-containing appliances, and what must be contained
in a retrofit or retirement plan. EPA is proposing that a retrofit or
retirement plan be created within 30 days of certain scenarios. The
Agency understands this timing is sufficient for an owner or operator
to either attempt to repair the leak with all necessary requirements as
described in section IV.C.3.b. or make a business decision to directly
begin the retrofit or retirement process. It is necessary to cap this
timing requirement to minimize emissions from leaks in the case where
an owner or operator fails to take any action after finding that their
applicable refrigerant-containing appliance is leaking above the
applicable leak threshold. After 30 days, the owner or operator must
begin developing a retrofit or retirement plan. The following scenarios
describe when a retrofit or retirement plan must be developed:
     An appliance is leaking above the applicable leak rate and
the owner or operator intends to retrofit or retire the appliance
rather than repair the leak;
     An appliance is leaking above the applicable leak rate and
the owner or operator fails to take action to identify or repair the
leak; or
     An appliance is continuing to leak above the applicable
leak rate after an attempted leak repair and verification testing.
    Developing the retrofit or retirement plan is a key process in
ensuring that each step of the plan is successfully performed such that
releases of HFCs are minimized and the reclaiming of the HFCs can be
maximized. EPA is proposing that the retrofit or retirement plan
include information regarding the location of the appliance,
characteristics of the appliance, a procedure for how the appliance
will be converted to accommodate a different refrigerant (if the
appliance is being retrofitted), plans for the disposition of any
recovered refrigerant and the appliance (if the appliance is being
retired), and a schedule for the completion of the appliance retrofit
or retirement. Characteristics of the appliance that would be
retrofitted or retired include the type and full charge of the
refrigerant used in the appliance, and for retrofitted, the type and
full charge of the refrigerant to which the appliance will be
retrofitted. In describing how the appliance would be retrofitted, the
owner or operator must include an itemized procedure for converting the
appliance to a different refrigerant, including changes required for
compatibility. This would also include any changes for compatibility
that relate to safety considerations to ensure the safety of
technicians and consumers when converting an appliance to a different
refrigerant, which would further serve one of the purposes identified
in subsection (h)(1). EPA is also proposing that the retrofit or
retirement plan must include information on how any recovered
refrigerant is being dispositioned. In the case of retiring an
appliance, the retirement plan would need to include how the appliance
is being dispositioned. EPA is proposing that the retrofit or
retirement plan include a schedule for completion of the retrofit or
retirement and, unless additional time is granted, that the schedule
would not exceed one year of the plan's date (not to exceed 12 months
from when the plan was finalized).
    EPA is proposing that an owner or operator may request relief from
the provisions of a retrofit or retirement plan if they are able to
establish that an

appliance is no longer leaking above the applicable leak rate within
180 days of creating the plan, and the owner or operator agrees to
repair all identified leaks within one year of the plan's date. The
owner or operator would be required to submit specified information to
EPA, including information regarding leaks in the appliance,
descriptions of the work completed/to be completed, and more, as found
in the proposed regulatory text.
    For IPR equipment, EPA is proposing that extensions could be
requested in cases where requirements or other applicable Federal,
state, local, or Tribal regulations would make it impossible to
complete the retrofit or retirement within one year. In this case,
owners or operators could be permitted additional time to the extent
needed to comply with the applicable regulations. EPA is also proposing
that extensions could be requested for IPR equipment if the equipment
is custom-built and the supplier of the appliance or one of its
components has quoted a delivery time of more than 30 weeks. In such
cases, the appliance or component must be installed within 120 days of
receipt. If additional time is needed, the owner or operator would need
to submit a request for the additional time to EPA. Further, EPA is
proposing that extensions could be requested to complete a retrofit or
retirement if the IPR equipment is located in an area subject to
radiological contamination or shutting down the appliance will directly
lead to radiological contamination. EPA is proposing that in this case,
additional time would be permitted to the extent necessary to complete
the retrofit in a safe working environment. EPA is not proposing
extensions specifically applicable to Federally owned equipment (see,
e.g., the provisions at 40 CFR 82.157(i)(3)) because EPA believes these
circumstances can be addressed under the other proposed extension
provisions, but EPA requests comment on this.
    EPA is requesting comment on all aspects of this proposal, and, in
particular, the proposed provisions for retrofit and retirement plans
for applicable refrigerant-containing appliances. EPA is requesting
comment on the timing for developing retrofit or retirement plans and
the timing for executing these plans. EPA is also requesting comment on
if the Agency should require that refrigerant be recovered as a part of
the retrofit or retirement plan, or if that is already sufficiently
covered by requirements under 40 CFR part 82, subpart F. Further, EPA
is seeking comment on requiring that if an owner or operator is
developing a retrofit plan, they must include that a lower GWP
refrigerant will be used in the retrofitted appliance. EPA notes that
it is not assuming early retirement of appliances as a result of the
proposed rule provisions. EPA is seeking comment on any potential
impacts of the proposed leak repair provisions on the retirement of
affected refrigerant-containing appliances.
g. Recordkeeping and Reporting
    EPA is proposing to include recordkeeping and reporting
requirements to support compliance with the proposed leak repair
provisions under subsection (h) for applicable refrigerant-containing
appliances that contain HFCs or certain substitutes for HFCs as a
refrigerant. For example, the requirements would control recordkeeping
and reporting practices, process, or activities for servicing and
repair that involves HFCs or a substitute for an HFC. As noted in
section II.B. of this document, EPA's authority to require
recordkeeping and reporting under the AIM Act is also supported by
section 114 of the CAA, which applies to the AIM Act and rules
promulgated under it as provided in subsection (k)(1)(C) of the AIM
Act.
    As discussed in section IV.C.2. above, this proposal covers
refrigerant-containing appliances with charge sizes of 15 pounds or
higher of a refrigerant that contains an HFC or a substitute for an HFC
that has a GWP above 53. The recordkeeping and requirements related to
the leak repair requirements under subsection (h) would be applicable
to the full range of appliances that are subject to the proposed leak
repair provisions, including those containing at least 15 pounds of
refrigerant with limited exemptions, as described in section IV.C.2.b.
for certain appliances. The proposed recordkeeping and reporting
requirements provide critical information about whether required
actions were taken and are part of the suite of compliance tools
included in this proposal. Compliance with the overall leak repair
requirements is intended to minimize the release of HFC and substitute
refrigerants and the Agency considers these recordkeeping and reporting
requirements necessary to readily assess compliance. Records that would
demonstrate noncompliance or are incomplete may be used for enforcement
purposes. The proposed requirements are informed in part by EPA's
consideration of its experience implementing similar regulations under
CAA section 608 at 40 CFR 82.157 and the recordkeeping and reporting
requirements that have been used to assure compliance with those
provisions.
    EPA is proposing recordkeeping requirements for refrigerant-
containing appliances with a charge size of 15 pounds or more of a
refrigerant containing an HFC or a substitute for an HFC with a GWP
above 53 under subsection (h) that are similar to those at 40 CFR
82.157(l). Where EPA is proposing requirements for recordkeeping, we
are proposing that record be maintained for three years in either paper
or electronic format. An owner or operator may contract out the record
generation responsibilities but retains ultimate liability for
compliance and must be able to access these records electronically or
in hard copy from the facility where the appliance is located. All
recordkeeping requirements can be found in Sec.  84.106(l) of the
proposed regulatory text. These records would be the primary means for
the facility to demonstrate compliance with the leak repair
requirements, and EPA would review them when evaluating compliance. EPA
could access these records in various ways, including, but not limited
to, via on-site review of the records or requesting them via an
information request. In general, EPA is proposing the following
recordkeeping requirements for owners and operators under subsection
(h):
     Maintain records documenting the full charge of
appliances;
     Maintain records, such as invoices or other documentation
showing when refrigerant is added or removed from an appliance, when a
leak inspection is performed, when a verification test is conducted,
and when service or maintenance is performed;
     Maintain retrofit and/or retirement plans;
     Maintain retrofit and/or extension requests submitted to
EPA;
     If a system is mothballed to suspend a deadline, maintain
records documenting when the system was mothballed and when it was
brought back on-line (i.e., when refrigerant was added back into the
appliance or isolated component of the appliance);
     Maintain records of purged and destroyed refrigerant if
excluding such refrigerant from the leak rate;
     Maintain records to demonstrate a seasonal variance; and
     Maintain copies of any reports submitted to EPA under the
proposed reporting requirements in this action.
    EPA is proposing reporting requirements for refrigerant-containing
appliances that with a charge size of 15 pounds or more of a
refrigerant containing an HFC or a substitute for an HFC with a GWP
above 53 under

subsection (h) that are similar to those at 40 CFR 82.157(m). The
proposed reporting requirements include notifications to EPA that
include specified information when:
     The owner or operator is seeking an extension to complete
repairs;
     The owner or operator is seeking an extension to complete
a retrofit or retirement plan;
     The owner or operator is seeking relief from the
obligation to retrofit or retire an appliance;
     When an appliance leaks 125 percent or more of the full
charge in a calendar year;
     The owner or operator is excluding purged refrigerants
that are destroyed from annual leak rate calculations for the first
time.
    Additional detail on these proposed recordkeeping and requirements
is available in the proposed regulatory text. Proposed recordkeeping
and reporting requirements in this action for ALD systems are described
in section IV.C.4.b.
    EPA is requesting comment on all aspects of this proposal, and, in
particular, the recordkeeping and reporting requirements associated
with the leak repair provisions in this proposal. EPA is requesting
comment on the information required in the recordkeeping and reporting
provisions and if there is any additional information that would be
relevant for the proposed leak repair requirements in this action.
4. Automatic Leak Detection Systems
    ALD systems on refrigerant-containing appliances are refrigerant
leak detection technologies calibrated to continuously monitor a
refrigerant-based system(s) for evidence of leaks and alert an operator
upon detection of a leak. Repairing leaks sooner further minimizes
emissions. Where ALD systems are used, it can result in early and
effective detection of leaks, so that the leaks can be repaired and
emissions of regulated substances or their substitutes can quickly be
mitigated. As part of the proposed regulatory requirements to implement
subsection (h)(1), EPA is proposing to require that ALD systems be used
for certain new and existing refrigerant-containing appliances to
detect leaks, which would trigger subsequent requirements. These
provisions would control practices, processes, or activities regarding
servicing, repair or installation of such appliances, which are a type
of equipment, and would involve a regulated substance or a substitute
for a regulated substance. When an ALD system detects a leak in a
refrigerant-containing appliance covered by this proposal, an owner or
operator of the appliance would be required to either perform
practices, processes, and/or activities to determine whether servicing
or repair of the appliance is necessary (i.e., calculating a leak rate
and assessing it compared to the applicable leak rate for the type of
appliance) or, alternatively, preemptively repair the leak (i.e.,
before adding refrigerant and calculating the leak rate). EPA is
proposing to explicitly permit preemptive repair of the leak as a
compliance option to avoid the need to add refrigerant to an appliance
with a known leak (which would otherwise generally be necessary to
calculate the leak rate and determine if the applicable leak rate is
exceeded). If the preemptive repair is being used as a compliance
option, it must occur within 30 days (or 120 days where an industrial
process shutdown would be necessary) of the alert. These proposed
requirements are expected to facilitate prompt repair of leaks, which
would further help minimize releases of regulated substances from
equipment.
    In the case of preemptive repair, this compliance option provides
the opportunity to repair an appliance that is known to be leaking
prior to the addition of refrigerant. When refrigerant is added to the
appliance that underwent preemptive repair, a leak rate calculation
would still be required. If the leak rate calculation (performed after
the addition of refrigerant for the follow-up verification test)
conducted after the preemptive repair reveals that the appliance had
leaked above the applicable leak threshold, the proposed suite of leak
repair requirements would still apply. The preemptive repair actions
can be considered in determining whether the suite of leak repair
requirements triggered by the exceedance of the applicable leak
threshold have been satisfied, but the owner or operator of the
appliance would still need to ensure that the leaks had been repaired
according to the proposed definition of repair and that the other
requirements proposed in 40 CFR 84.106 (e.g., initial and follow-up
verification tests, leak inspections (where applicable) and related
recordkeeping) had been met.
    EPA understands that for reasons other than this proposal, ALD
systems already are in use to a certain extent. For example, some
owners and operators may already use ALD systems to serve as an early
warning system for detecting and repairing leaks. Some owners and
operators may choose to install ALD systems from an economic
perspective as early detection and repair of leaks can avoid costs of
replacing the released refrigerant and operating equipment at
suboptimal levels and/or the loss of perishable products due to failure
to maintain required cooling. Further, there are provisions under 40
CFR 82.157 where an owner or operator of a covered appliance with ODS
refrigerants may choose to use an ALD system in place of performing
regular leak inspections as a part of the leak repair provisions under
CAA section 608 at 40 CFR 82.157. Nothing in this proposal changes the
requirements related to ALD systems under CAA section 608 for equipment
containing only ODS refrigerants. In other words, an owner or operator
of an appliance that uses ODS-containing refrigerants will continue to
be required to meet any and all requirements under 40 CFR 82.157 for
that appliance, including if they choose to use an ALD system to comply
with requirements under 40 CFR 82.157.
    Additionally, there are safety standards that apply when using
certain HFCs (whether neat or in a blend) and/or substitutes for HFCs
that have been classified as lower flammability. Lower flammability
refrigerants in this context are those that are classified by ASHRAE as
A2L refrigerants.\65\ UL Standard 60335-2-40 currently requires the use
of leak detectors for electrical heat pumps, air conditioners and
dehumidifiers containing A2L refrigerants.66 67 Under that
standard, leak detectors that detect pressure loss are required in
cases that the prescribed A2L charge limit is exceeded (which is
typically around four pounds for permanently installed applications).
That standard also prescribes that refrigerant leak detectors be
installed at the factory for applicable appliances

and have factory established set points for detection to avoid
potential buildup of concentrations of flammable refrigerants.
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    \65\ ASHRAE Standard 34-2022 assigns a safety group
classification for each refrigerant which consists of two
alphanumeric characters (e.g., A2 or B1). The capital letter
indicates the toxicity class (``A'' for lower toxicity) and the
numeral denotes the flammability. ASHRAE recognizes three
classifications and one subclass for refrigerant flammability. The
three main flammability classifications are Class 1, for
refrigerants that do not propagate a flame when tested as per the
ASHRAE 34 standard, ``Designation and Safety Classification of
Refrigerants;'' Class 2, for refrigerants of lower flammability; and
Class 3, for highly flammable refrigerants, such as the hydrocarbon
refrigerants. ASHRAE recently updated the safety classification
matrix to include a new flammability subclass 2L, for flammability
Class 2 refrigerants that burn very slowly.
    \66\ UL. 2019. ``Understanding UL 60335-2-40 Refrigerant
Detector Requirements.'' https://www.ul.com/news/understanding-ul-60335-2-40-refrigerant-detector-requirements.
    \67\ UL 60335-2-40, 2019. Household And Similar Electrical
Appliances--Safety--Part 2-40: Particular Requirements for
Electrical Heat Pumps, Air-Conditioners and Dehumidifiers. Third
Edition. November 1, 2019.
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a. Proposed Automatic Leak Detection Requirements
    EPA is proposing to require the use of ALD systems for certain
RACHP equipment. Specifically, EPA is proposing to require ALD systems
for IPR and commercial refrigeration appliances containing 1,500 pounds
or more of a refrigerant that contains an HFC or a substitute for an
HFC with a GWP above 53 for both new and existing equipment. EPA is not
proposing to require ALD systems for comfort cooling appliances. As
previously noted, EPA considers the leak inspections that are proposed
for codification at 40 CFR 84.106(g) and the requirements related to
ALD systems that are proposed for codification at 40 CFR 84.108 to be
separate. However, as previously discussed, in certain circumstances
the proposed leak inspection requirements would recognize use of the
ALD systems that meets certain requirements under the proposed 40 CFR
84.108 as a compliance option that may be used in lieu of quarterly or
annual leak inspections.
    Beginning on January 1, 2025, for new refrigerant-containing
appliances, EPA is proposing that an ALD system be installed as part of
the overall appliance installation, either during the installation of
the new appliance or within 30 days from when the new appliance is
installed. EPA understands that depending on the type of ALD system, it
may be more practicable to install an ALD system during the appliance
installation. In other cases, additional time may be needed to secure a
contractor or technician to install the ALD system, or there may be
unforeseen delays in acquiring an ALD system. For existing refrigerant-
containing appliances, EPA is proposing that an ALD system must be
installed within one year of the effective date of the final rule.
    EPA is proposing that refrigerant-containing appliances in the
commercial refrigeration and IPR subsectors with a charge size of 1,500
pounds or more with a refrigerant that contains an HFC or a substitute
for an HFC that has a GWP above 53 (whether the HFC or substitute is
used neat or in a blend) would be required to use ALD systems. The
refrigerants that would be covered are the same as for other leak
repair provisions proposed in this action, but the proposed full charge
size cutoff for using ALD systems (1,500 pounds) is greater than that
of the other leak repair provisions in this proposal (15 pounds). EPA
understands that using ALD systems for refrigerant-containing
appliances that have lower refrigerant charge sizes (i.e., below 1,500
pounds) may be an option an owner or operator could take so they are
alerted to leaks sooner. This could also be an option an owner or
operator takes for specific refrigerants. However, discussed later in
this section, EPA is not proposing to require use of ALD systems for
refrigerant-containing appliances with less than 1,500 pounds.
Similarly, EPA also understands that owners and operators with larger
charge size appliances may be more likely to have in place refrigerant
management plans, routine equipment inspections, or other formal or
even informal mechanisms aimed at reducing refrigerant losses.
    EPA considered a number of potential options for the threshold for
requiring ALD systems. The Agency considered thresholds as low as 15 or
50 pounds to match the proposed leak repair requirements or as
analogous with the longstanding CAA section 608 leak repair threshold
for ODS-containing appliances, respectively. The Agency also considered
as high as 2,000 pounds, which is consistent with the current state
requirement in California.\68\ Throughout this proposal, EPA uses
charge sizes to differentiate requirements; for example, EPA proposed
500 pounds as a cutoff for the frequency of inspections for certain
appliances and the Agency also considered this as a potential cutoff
for proposing to require ALD systems. Further, another potential cutoff
considered was 200 pounds, which was used as a point of inflection for
proposing certain GWP-limit based restrictions under the Technology
Transitions program.\69\
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    \68\ California Code of Regulations, Regulation for the
Management of High Global Warming Potential Refrigerants for
Stationary Sources. Available: https://ww2.arb.ca.gov/sites/default/files/2020-07/finalfro_0.pdf.
    \69\ In the proposed Technology Transitions rule (87 FR 76738,
December 15, 2022), the inflection point of 200 pounds for a charge
size of equipment in certain subsectors is used to propose different
GWP-limit based restrictions. This point was considered based on
safety standards ANSI/ASHRAE Standard 15-2019 and UL 60335-2-89,
which set a charge limit set a charge limit for using lower
flammability refrigerant for certain applications that vary by
refrigerant but does not exceed 200 pounds.
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    EPA is also aware of other cutoffs used for requirements for using
ALD systems in certain states and internationally. Across states, the
Agency is aware that California \70\ has a similar provision with a
cutoff of 2,000 pounds that has been in place for over ten years and
Washington \71\ is considering a cutoff of 1,500 pounds in a recent
proposal for requiring ALD systems on refrigeration equipment.
Internationally, the EU \72\ uses a CO2e-based threshold,
requiring that leakage detection systems be installed for stationary
equipment (including refrigeration, air conditioning, heat pumps, and
fire protection equipment and electrical switch gear and organic
Rankine cycles) that contain 500 or more metric tons of
CO2e. For example, if a stationary refrigeration appliance
is charged with R-404A (which has a GWP of 3,920), then the minimum
charge size required to use a leakage detection system would be
approximately 281 pounds under the EU's approach. EPA notes that it is
considering using either a pounds-based approach or a CO2e-
based approach to establishing the threshold for these requirements.
While there are certain advantages to CO2e approaches, such
as providing an advantage for lower GWP refrigerants, the Agency also
understands that for compliance purposes, limits based on pounds also