Administrator Regina McCarthy 

Environmental Protection Agency 

Ariel Rios Building 

1200 Pennsylvania Avenue, N.W. 

Washington, DC 20460

By Email

October 6, 2015

Petition for Change of Status of HFCs under Clean Air Act Section 612 

(Significant New Alternatives Policy)

Dear Administrator McCarthy: 

The Natural Resources Defense Council (NRDC) and the Institute for Governance 

& Sustainable Development (IGSD) congratulate the United States Environmental 

Protection Agency (EPA) on its successful adoption of final “change of status” standards 

adjusting the list of acceptable alternatives maintained under the Significant New 

Alternatives Policy Program (SNAP) to list as unacceptable certain high global warming 

potential (GWP) chemicals from a number of applications. These rules are an important 

first step to ensuring that SNAP continually adjusts to eliminate the most environmentally 

harmful chemicals from the approved list as additional, environmentally preferable 

substitutes become available. 

After this important step forward, much work remains to be done. As a next step, 

NRDC and IGSD hereby petition EPA to remove the chemicals listed below from the list 

of acceptable substitutes for the specified end uses under EPA’s SNAP program. In the 

following petition, NRDC and ISGD request changes of listing status for the high-GWP 

chemicals we understand to be most used in the US marketplace for each application in 

which a lower-GWP alternative is available. There may be numerous, infrequently-used 

high-GWP chemicals similar to those we are petitioning to ban whose status we have not 

specifically requested be changed. NRDC and IGSD ask EPA to consider changing the 

listing status of these chemicals alongside those explicitly requested in this petition.

This petition is filed pursuant to Section 612(d) of the Clean Air Act and 40 C.F.R 

§ 82.184(b)(3). Under section 612 of the Clean Air Act, EPA has the responsibility to 

evaluate alternatives to ozone-depleting substances (ODSs) identified in section 602 and to 

publish a list of acceptable and unacceptable substitutes through the SNAP program. EPA 

also has the authority to revise this list on its own, or in response to a petition, to remove a 
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substitute previously listed as acceptable. As EPA determined in the SNAP delisting rule, 

a chemical once deemed an acceptable alternative can be made unacceptable by the 

emergence of newer alternatives with lower overall human health and environmental 

impacts.

It is imperative that EPA continue the process it began in the SNAP delisting rule. 

There are many high-GWP refrigerants and substances used for replacement of other ODSs

still on the SNAP approved list for which adequate substitutes are available. Furthermore,

there are some substances on the SNAP list marketed as refrigerants that are 

counterproductive to environmental protection because they, if carelessly used, can 

contaminate recycled refrigerants risking damage to equipment, endangering service 

technicians, and discouraging recycling. Accordingly, NRDC and IGSD hereby petition 

EPA to make the following changes to the listing status of approved alternatives under 

SNAP:

1) Remove R-404A and R-507A from the list of acceptable substitutes in all 

new and retrofit stationary and transportation applications effective January 1, 2017. Ban 

the servicing of systems with new R-404A and R-507A refrigerant effective January 1, 

2020. 

2) Remove HFC-23 from the list of acceptable substitutes for all new and 

retrofit industrial process refrigeration applications effective January 1, 2017. Apply 

narrow use restrictions to HFC-23 in very low temperature refrigeration and total flooding 

fire suppression, allowing only for applications in which all other approved alternatives are 

physically inadequate effective January 1, 2017. 

3) Remove sulfur hexafluoride (SF6), perfluorinated compounds (PFCs), 

HCFC-22 blends, HCFC-124, and trifluoroiodomethane (CF3I) from the list of acceptable 

substitutes in all flooding and streaming fire suppression applications effective January 1, 

2019. 

4) Remove HFC-134a from the list of acceptable substitutes in all new 

centrifugal, screw, reciprocating, and scroll chillers effective January 1, 2019.

5) Remove HFC-134a from the list of acceptable substitutes in all new 

medium- and heavy-duty vehicle air conditioning effective January 1, 2021. 

6) Remove HFC-134a from the list of acceptable substitutes in new household 

refrigerators and freezers effective January 1, 2021.

7) Remove R-410A from the list of acceptable substitutes in all new
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a. Portable factory sealed air conditioners and dehumidifiers effective January

1, 2019

b. Air-cooled centrifugal, screw, reciprocating, and scroll chillers effective 

January 1, 2019

c. Water-cooled centrifugal, screw, reciprocating, and scroll chillers effective 

January 1, 2023

d. Light commercial air conditioning effective January 1, 2023

e. Household residential split air conditioning effective January 1, 2025

(NRDC and IGSD request that EPA defer consideration of the petition for 

those end-use sectors (7(d)-7(e)) that currently lack an approved low-GWP 

alternative until EPA has SNAP-approved a low-GWP alternative.)

8) Remove R-410A, R-407A, R-407C, and R-407F from the list of acceptable 

substitutes in all new and retrofit cold storage warehouses and industrial process 

refrigeration effective January 1, 2023. 

9) Remove R-410A, R-407C, and R-407F from the list of acceptable 

substitutes in all new and retrofit industrial process air conditioning effective January 1, 

2023. 

10) Restrict the sale of small canisters of HFC-134a to certified technicians 

only, effective January 1, 2017 or earlier. 

11) Reference international standards IEC 60335-2-40 and ISO5149 when 

granting SNAP approval for new alternatives in the end uses covered by those standards.

12) Remove HFC-134a, HFC-245fa, HFC-365mfc and HFC-227ea from the list 

of acceptable substitutes in rigid polyurethane spray foams effective January 1, 2017. 

I. Background

HFCs were originally added to the SNAP list because they were deemed an 

improvement on the ODSs they replaced – chlorofluorocarbons (CFCs) and 

hydrofluorocarbons (HCFCs) that deplete the ozone layer and also have high global 

warming potentials (GWPs). While HFCs are not ODSs, some HFCs are extremely potent 

greenhouse gases (GHGs), with GWPs thousands of times greater than that of carbon 

dioxide (CO2).

Currently, HFCs make up 1.5 percent of the United States’ greenhouse gas 

emissions, but in the U.S. alone, emissions of HFCs are expected to triple by 2030.i

Atmospheric concentrations of HFCs are increasing as well, with HFC -134a increasing by 

an average of 10% per year from 2006 to 2012.ii Even though HFCs may currently make 
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up a small piece of global climate emissions, their projected rapid growth underscores the 

urgent need to replace these chemicals with lower-GWP alternatives. Further, without 

stringent rules in place, HFC emissions increases could counteract the progress EPA is 

striving to make in other sectors to reduce carbon pollution.

HFCs are relatively short-lived GHGs that preventing thermal radiation from 

escaping earth’s atmosphere by strongly absorbing wavelengths emitted by the sun. 

Commonly used HFCs persist in the atmosphere for 5-50 years and therefore cause more 

immediate damage to climate than their 100-year GWPs would indicate. Inaction on HFC 

consumption threatens to exacerbate climate change feedback loops like increased 

atmospheric water vapor, decreases in arctic albedo and increased methane releases, carbon 

cycle disruptions, and other drastic short term accelerators to climate change. 

The relatively short-lived nature of these pollutants offers a unique opportunity to 

reverse and avoid some of the effects of climate change. EPA has the opportunity, through 

its SNAP program, to rapidly protect the global climate by removing the most harmful and 

unnecessary chemicals from the list of approved alternatives. 

The SNAP program implements Section 612 of the Clean Air Act. The SNAP 

program was created to assure the health and environmental safety of alternatives for 

ozone-depleting substances. The purpose of the SNAP program is “to allow a safe, smooth 

transition away from ozone-depleting compounds by identifying substitutes that offer lower 

overall risks to human health and the environment.”iii Section 602 of the Clean Air Act

contains a list of Class I and Class II ozone-depleting substances that have been or are 

being phased out. Under the SNAP program EPA evaluates proposed substitutes and 

classifies the substitutes as acceptable, acceptable subject to use limits or conditions, or 

unacceptable.iv 

EPA’s acceptability determinations are comparative evaluations, where EPA looks 

not only at the proposed substitute in comparison to the relevant Class I or Class II 

substance listed in Section 602, but also in comparison to “other substitutes for the same 

end-use.” In comparing these substitutes directly with each other, EPA then may “prohibit 

the use of those substitutes found, based on the same comparisons, to increase overall 

risks.”v This progressive comparative analysis allows the SNAP program to continually 

promote new and less environmentally harmful substitutes as they are developed and listed. 

The comparative analysis requires EPA to analyze, among other things, 

“atmospheric effects and related health and environmental impacts... [and] general 

population risks from ambient exposure to compounds with direct toxicity and to increased 

ground-level ozone.”vi Further, the “overall risk characterization will consider such factors 

as: Toxicity and exposure -- both human health and ecological; chlorine loadings; ozonedepletion potential; global-warming potential; and flammability.”vii
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EPA’s recent SNAP delisting rule was an important step forward in employing this 

comparative analysis to revise and update the SNAP list, and it is imperative that the 

Agency continue this successful approach with respect to more end-uses and chemicals. 

NRDC and IGSD petition to remove the particular chemicals listed above because 

all of them meet two requirements. First, each chemical has an unacceptably high GWP in 

comparison with one or more lower-GWP alternatives that possess similar thermodynamic 

characteristics.viii Second, unless otherwise noted, the available alternatives to the 

chemicals proposed for SNAP unacceptability listing can achieve equal or greater energy 

efficiency in hardware design specifically for these new alternatives and taking on board 

the latest technical advances.

NRDC and IGSD submit that all of the chemicals described below are good 

candidates for delisting with respect to their particular end-use(s), and EPA should act to 

delist them as quickly as possible.

II. Analysis of Chemicals for which Change of Status is Requested

1. Remove R-404A and R-507A from the list of acceptable substitutes in all 

new and retrofit stationary and transportation applications effective January 1, 2017. 

Ban the servicing of systems with new R-404A and R-507A refrigerant effective January 

1, 2020. 

NRDC and IGSD petition to remove R-404A and R-507A from the list of 

acceptable substitutes for all class I and class II ODSs in all new and retrofit applications 

effective January 1, 2017. 

R-404A is a nearly azeotropic blend of HFC-143a, HFC-125, and HFC-134a used 

primarily in commercial refrigeration, industrial refrigeration, and refrigerated 

transportation. R-404A’s high GWP of 3902 makes it unsuitable for use now that lowerGWP alternatives have been developed and are commercially available. R-507A consists of 

equal parts HFC-125 and HFC-143a, making it close to R-404A in performance but with 

an even higher GWP of 3985. Its status as an acceptable alternative to class I and II ODSs 

should therefore be removed along with R-404A.

In its July final rule, EPA disallowed the use of R-404A and R-507A in commercial 

refrigeration in stand-alone, condensing unit, and direct and indirect supermarket retail 

food refrigeration and vending machines.

ix NRDC and IGSD reiterate their support for this 

important action and view it as an important first step in updating the SNAP list to 

eliminate obsolete high-GWP HFCs. 
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Moving forward from EPA’s delisting of R-404A and R-507A from commercial 

applications, the next large end-use that requires action is industrial refrigeration. R-404A 

and R-507A are used over a wide range of applications for both low-temperature and 

medium-temperature refrigeration. These systems cool with direct-expansion coils and 

typically have site-installed refrigerant pipework that leak between 5-10% per yearx

. 

There are several suitable lower-GWP alternatives for industrial applications, 

including the well-established R-407 series (in particular, R-407A and R-407F) and the 

recently developed R-448A, R-449A and R-452A blends. The R-448A and R-449A

refrigerants, while not yet extensively deployed, offer GWP reductions of about 65% below 

R-404A, maintain A1 non-flammability, and can be retrofitted into existing systems 

without an oil change or used in new equipment. R-452A benefits are talked about below. 

Thermodynamic efficiency often surpasses R-404A and R-507A levels with modest 

adjustments to the thermal expansion device. 

The next major end-use that for which R-404A and R-507A should be delisted is 

the refrigerated transportation sector. Refrigerated trucks often travel through a wide range 

of climatic conditions and therefore require refrigerants with low compressor discharge 

temperatures to avoid system damage in high ambient temperature conditions. R-452A 

offers a non-flammable, low discharge temperature alternative with a 45% reduction in 

GWP from R404A. R-452A’s application is being considered under SNAP and Chemours 

has committed to making R-452A generally available 12 months after approval. R-452A 

can be used to retrofit existing equipment or incorporated into new system designs and has 

demonstrated thermodynamic efficiency and capacity comparable to that of R-404A in 

most configurations. The R-407 series of refrigerants may also be used in the transportation 

sector as long as appropriate measures (e.g. liquid injection) are taken to mitigate high 

compressor discharge temperature. 

While R-452A and the R-407 series offer non-flammability and significant 

reductions in GWP below R-404A, this sector will eventually need to move towards longterm near-zero-GWP solutions. EPA should not, however, hesitate to grant SNAP approval 

to interim refrigerants like R-452A while industry and others research future solutions. 

Thermo King and Carrier, the two major manufacturers of refrigerated 

transportation equipment, have both indicated the near-immediate availability of R-452A 

systems. Thermo King has committed to making R-452A equipment available as soon as 

SNAP approves it, while Carrier has been selling R-452A systems in Europe for a 

considerable period. Further delaying the change of listing status for R-404A in 

transportation refrigeration only serves to impede industry’s efforts to transition this enduse. 
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In addition to the proposed SNAP unacceptability listing on new and retrofit use of 

R-404A and R-507A, NRDC and IGSD propose a service ban on new R-404A and R-507A 

refrigerant effective January 1, 2020. Intended to avoid a long service tail, the ban would 

require owners of R-404A and R-507A systems to retrofit before 2020 so that servicing 

could be done with available R-448A, R-449A, R-452A or R-407-class refrigerants. 

With alternatives available in all applications, further SNAP action on R-404A and 

R-507A will result in significant greenhouse gas emissions savings from multiple sectors.

2. Remove HFC-23 from the list of acceptable substitutes for all new and 

retrofit industrial process refrigeration applications effective January 1, 2017. Apply 

narrow use restrictions to HFC-23 in very low temperature refrigeration and total 

flooding fire suppression, allowing only for applications in which all other approved 

alternatives are physically inadequate effective January 1, 2017. 

HFC-23, with its very high GWP of 14,800, has become obsolete in the 

applications for which it is currently SNAP approved except for a very narrow range of 

special uses. NRDC and IGSD petition EPA to list HFC-23 as unacceptable in industrial 

process refrigeration and to place narrow use restrictions on very low temperature 

refrigeration and total flooding fire suppression to permit only those applications for which 

all other alternatives are physically inadequate. 

HFC-23, famous for being a mostly unwanted high-GWP byproduct of the HCFC22 manufacturing process, has a very low boiling point of -116°F and is therefore suited to 

certain refrigeration and fire suppression applications. In particular, HFC-23 is important in 

very low temperature refrigeration applications like medical storage and other high-value 

low-temperature refrigeration applications. In total flooding fire suppression, HFC-23 is 

used in applications that demand high vapor pressure at very low space temperature and 

under special circumstances in which very high quantities of fire extinguishing agent must 

be discharged in occupied spaces. HFC-23’s no-observed-adverse-effect-level (NOAEL) is 

a factor of three higher than the next highest fire extinguishing agent and it is therefore 

uniquely able to safely extinguish or prevent fires in occupied spaces. Moreover, both of 

the applications listed above are generally non-emissive and the climate impact of use in 

these cases is negligible. 

That being said, HFC-23’s GWP makes its use in nonessential applications

unacceptable—even within the SNAP categories mentioned above. NRDC and IGSD 

believe that as long as HFC-23 is confined to its current applications, its use in the U.S.

does not represent a major climate risk. As such, rather than list HFC-23 as unacceptable, 

EPA should issue use restrictions on HFC-23 in both very low temperature refrigeration 

and total flooding fire suppression to ensure that its use does not expand as other HFCs are 

removed from the list of approved alternatives. 
8

In addition, HFC-23 should be delisted from industrial process refrigeration given 

the availability of R-717 (ammonia) systems for large industrial applications and the 

availability of R-407A/F, R-448A, and R-449A for small and medium industrial distributed 

systems. Note that R-448A and R-449A are not yet SNAP approved for industrial 

applications, but they show increased performance in all applications currently served by 

R-404A. Additional SNAP approval action will ensure a full suite of suitable alternatives to 

HFC-23 in industrial refrigeration applications. 

3. Remove sulfur hexafluoride (SF6), perfluorinated compounds (PFCs), 

HCFC-22 blends, HCFC-124, and trifluoroiodomethane (CF3I) from the list of 

acceptable substitutes in all flooding and streaming fire suppression applications 

effective January 1, 2019. 

NRDC and IGSD petition EPA to list SF6, PFCs, HCFC-22 blends, HCFC-124, and 

CF3I as unacceptable under SNAP on account of the environmental hazards they pose and 

in light of the many fire suppression alternatives available. It is our understanding that none 

of these agents are currently used in fire suppression and therefore removal from the list of 

alternatives is preemptive of unnecessary future use. 

SF6 is an inorganic fire suppression agent currently SNAP-approved in military and 

civilian aviation applications despite its extremely high GWP of 23,900. Historically, SF6 

has been used as a simulant gas used by the US Air Force to test the flow properties of 

halon fire protection systems. 

PFCs are persistent and environmentally harmful chemicals also currently SNAPapproved in fire suppression end uses where safer alternatives are listed. PFCs reached the 

marketplace in the 1990s to considerable acclaim, but failed to gain large market share and 

are no longer believed to be manufactured or installed.

HCFC-22 blends, HCFC-124, and CF3I are ozone depleting substances for which 

suitable HFC and non-HFC alternatives exist. They should summarily be removed from the 

list of approved alternatives in all flooding and streaming fire suppression applications. 

4. Remove HFC-134a from the list of acceptable substitutes in all new 

centrifugal, screw, reciprocating, and scroll chillers effective January 1, 2019. 

Centrifugal Chillers

Large centrifugal chillers are used to efficiently cool large commercial buildings. 

These chillers have traditionally used CFC-11, CFC-12, and HCFC-123. CFC-11 and 

HCFC-123 are low pressure refrigerants, meaning their circuits operate below atmospheric 

pressure and benefit from lower refrigerant leakage rates than more-common positive 
9

pressure circuits. In low-pressure designs, outside air tends to leak into the refrigerant 

circuit rather than refrigerant leaking out of the circuit, as with medium and high pressure 

refrigerants. 

The use of HFC-134a in these end uses raises different concerns. HFC-134a is a 

medium pressure refrigerant that suffers from both a high GWP and the propensity to leak 

into the atmosphere. Manufacturers who have shifted out of low pressure CFC-11 or 

HCFC-123 chillers to HFC-134a have incurred a penalty on refrigerant leakage in both 

cases and, in the case of HCFC-123, a GWP increase of more than a factor of eighteen. In 

addition, HFC-134a’s theoretical coefficient of performance (COP) is 6% lower than CFC11’s and approximately 5% lower than HCFC-123’sxi. To avoid the transition penalties of 

lower energy efficiency and higher refrigerant leak rates, at least one manufacturer is 

selling low-pressure centrifugal chillers using HCFC-123.

The remaining manufacturers started using medium-pressure HFC-134a in 

centrifugal chillers, and now lower-GWP alternatives are available that are dramatically 

better with respect to human health, environment, and technical performance.

The modern low-pressure alternative, HFO-1233zd, has excellent properties 

including a GWP of 7, A1 non-flammability and nontoxicity, and a theoretical energy 

efficiency about 3% higher than HFC-134a. HFO-1233zd will require equipment redesign 

irrespective of what refrigerant is being used now, as its pressure is different than that of 

HFC-134a and HCFC-123. Nonetheless, the three-pronged benefit of low GWP, low 

leakage, and high energy efficiency make the redesign effort worthwhile: HFO-1233zd 

should satisfy the market for large centrifugal chillers far into the future.

Medium pressure alternatives to HFC 134a are also available. SNAP-approved 

HFO-1234ze provides an alternative with similar theoretical efficiency to HFC-134a and a 

GWP of <1. HFO-1234ze is classified as having 2L flammability, meaning that certain 

standards updates will be necessary for HFO-1234ze chillers to be widely commercially 

available. In particular, the American Society of Heating, Refrigeration, and Air 

Conditioning Engineers (ASHRAE) Standard 15 and Underwriters Laboratories (UL)

Standard 60335-2-40 need to be updated to include 2Ls, followed by the International

Mechanical Codes and Uniform Mechanical Codes (UMC and IMC) adopting references to 

these updated standards. The necessary updates for HFO-1234ze sales in air cooled chillers 

are expected in 2016, while standards for water-cooled chillers in mechanical rooms will be 

available in either 2018 or 2021, depending on the success of several code integration 

strategies. 

Additional medium pressure alternatives exist; Honeywell’s R-450A and 

Chemours’s R-513A offer design-compatible HFC-134a alternatives that can be rapidly 

adopted—with only changes to controls—while HFO-1234ze redesigns are completed and 
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building codes become fully compatible with 2L refrigerants. These transitional 

refrigerants offer roughly a 50% GWP reduction from HFC-134a and are nonflammable. In 

the case of R-513A, energy efficiency is nearly thermodynamically equal to that of the 

HFC134a being replaced. R-450A suffers a more significant efficiency penalty and may 

not be ideal from a total climate impact standpoint. 

Medium-pressure chiller manufacturers can employ R-450A or R-513A as a simple, 

interim solution if a full conversion to HFO-1234ze or HFO-1233zd is for some reason not 

feasible by 2019. R-513A and R-450A are not suitable long-term solutions, however, 

because they do not reduce the GWP to acceptable long term levels. These refrigerants may 

be the choice only in HFC-134a applications where it is not yet feasible to mitigate 

flammability of currently available lower-GWP refrigerants.

Screw, Reciprocating, and Scroll Chillers

HFC-134a is also currently used in screw chillers and to a much lesser extent 

reciprocating and scroll chillers, as an alternative to class I and II ODSs. Screw chiller 

compressors require medium- or high-pressure working fluids; as such, HFO-1234ze, R450A, and R-513A are all suitable alternatives in this product class. Similar to the 

discussion of centrifugal chillers above, R-450A and R-513A may be used as interim 

solutions based on existing designs, or manufacturers may move straight to HFO-1234ze 

redesigns in screw chiller offerings. HFO-1234ze’s efficiency and low GWP make it the 

ideal long-term market-driven solution for this smaller class of chillers, while R-450A and 

R-513A constitute possible interim step solutions. These non-flammable solutions may 

need to be maintained for special public safety situations in the future, but not for 

stationary chillers.

5. Remove HFC-134a from the list of acceptable substitutes in all new 

medium- and heavy-duty vehicles effective January 1, 2021. 

The technology developed to replace HFC-134a in motor vehicle air conditioning 

(MAC) passenger vehicles and light-duty trucks is equally applicable to heavy-duty trucks 

and most off-road vehicles.xii As such, we incorporate by reference our October 2014 

comments on that transition (See SNAP Delisting Rule, Docket No. EPA-HQ-OAR-2014-

0198-0136). HFO-1234yf, HFC-152a, and CO2 are SNAP listed as alternatives to HFC134a for the MAC sector and, so far, all companies that are phasing down HFC-134a have 

selected HFO-1234yf. HFO-1234yf is not currently SNAP approved for medium- and 

heavy-duty vehicles, but SNAP has indicated that it will begin approvals starting with the 

medium- and heavy-duty vehicles that most directly resemble light-duty vehicles. 

NRDC and IGSD therefore petition to list HFC-134a unacceptable for medium- and 

heavy-duty vehicles MACs after MY 2021 with some exceptions.
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Heavy-duty on-road and off-road vehicles use components and systems from the 

same suppliers as those for light-duty vehicles and will therefore benefit from the current 

phase out of HFC-134a. In addition, heavy-duty vehicles have the advantage of more 

available space in engine compartments, which makes redesign and implementation of lowGWP refrigerants simpler than for light-duty vehicles where it is sometimes necessary to 

wait for a major model upgrade in order to fit the system. 

The larger available space in the engine compartment of large trucks compared to 

passenger vehicles also makes it easier to implement secondary-loop MACs (SL-MACs). 

SL-MACs reduce the refrigerant charge and leakage by up to 50% in systems with single 

cooling points and to reduce the refrigerant charge and leakage by up to 75% or more in 

systems with two cooling points as a result of shorter refrigerant hoses and fewer 

refrigerated component connections. Trucks with sleeper cabs typically have one cooling 

point in the driver’s compartment and one cooling point in the sleeper cab. Trucks with 

electrically-powered MACs to allow comfort while parked without the engine running can 

implement hermetically sealed low-GWP systems with near-zero life-cycle refrigerant 

emissions. 

Suppliers of HFO-1234yf have confirmed ample supplies of HFO-1234yf from 

production facilities in China and Japan and additional production facilities are under 

construction at two locations in the United States and elsewhere. CO2 is available in vast 

quantities, while HFC-152a production be expanded or diverted from aerosol product uses 

where it is no longer environmentally acceptable. A contested application patent protects 

HFO-1234yf, but the patents for CO2 and HFC-152a have expired. 

NRDC and IGSD also suggest that EPA collaborate with other federal and state 

authorities to incentivize truck manufactures to incorporate reliability and fuel efficiency 

measures in addition to reducing refrigerant emissions. Design changes for increased fuel 

efficiency include fluid valves (rather than air dampers) to prevent hot antifreeze from 

entering the cab during air conditioning, controls that dehumidify and demist at evaporator 

temperatures optimized for technical and fuel performance (rather than over-cooling and 

reheating air), and integration with engine controls to cool during deceleration and low 

power loads in order to minimize incremental fuel consumption (during deceleration 

cooling, the air conditioner fan speed can be controlled to maintain comfort). Design 

changes for minimizing refrigerant leaks include fewer and better leak-tight fittings, lesspermeable hoses, mounting to reduce harmonic vibration, and leak checking after charging 

using more sensitive detectors. 

Removing SNAP approval for HFC-134a from medium and heavy trucks on the 

same schedule as passenger vehicles and light trucks will help the alternatives achieve full 

economy of scale. A SNAP listing of unacceptable after model year 2021 will also help 

consumers save money on infrastructure changes because a national HFC-134a phase down
12

schedule will be in place. Specifically, synchronized bans will shut down refrigerant supply 

streams and will induce the HFC-134a service tail to follow a similar trajectory for both 

light-duty and heavy-duty vehicles. The necessary supply and maintenance infrastructure 

will therefore be phased down simultaneously. NRDC and IGSD urge EPA not to allow 

additional time to pass between the ban of HFC-134a in light-duty and heavy-duty 

vehicles.

For situations where public safety cannot be guaranteed or where technology cannot 

be implemented effectively by 2021, non-flammable options like R-450A and R-513A may 

be used for specific applications. 

6. Remove HFC-134a from the list of acceptable substitutes in new 

household refrigerators and freezers effective January 1, 2021. 

Across the United States, at least 150 million domestic refrigerators, freezers, and 

combination units preserve food using HFC-134a. During their lifetimes, these units do not 

typically leak much HFC-134a, but improper disposal frequently results in the entire

refrigerant charge being vented to the atmosphere. Because improper disposal is prevalent 

and hard to control, domestic refrigerators and freezers have a significant impact on US 

greenhouse gas emissions. 

In order to reduce these emissions, NRDC and IGSD petition EPA to remove HFC134a from the list of acceptable class I and II ODS substitutes effective January 1, 2021. 

Updated Department of Energy (DOE) energy efficiency standards are also expected to go 

into effect for domestic refrigeration equipment in that year, so we suggest a coordinated 

approach that allows for a single redesign to incorporate both refrigerant and efficiency 

upgrades. 

Several alternatives to HFC-134a are being explored, including HFO-1234yf, HFO1234ze, propane (R-290), isobutane (R-600a), R-513A, and R-450A. HFO-1234yf has the 

benefit of being nearly design compatible with HFC-134a, although adjustments to 

desiccants, expansion valves, and heat exchangers may be necessary to match HFC-134a 

efficiency. HFO-1234ze offers a more efficient, lower-capacity version of its cousin that 

will require more redesign but offers greater life cycle benefit. 

Propane and isobutane, two hydrocarbons widely used abroad, provide an excellent 

potential option. Today, these options are restricted by UL’s and EPA’s charge limit of 

57g in domestic refrigeration applications—a charge limit too small to build a typical 

refrigerator/freezer with just one refrigerant circuit. Given the widespread and apparently 

safe use of units with more than 57 grams abroad (nearly half a billion units are in usexiii), 

we believe that UL and EPA should approve use conditioned on appropriate safety 

mitigation. If UL or EPA did so, the US market could follow the major shift to 
13

hydrocarbon refrigerators that has already occurred abroad. Hydrocarbons offer potential 

efficiency gains over HFC-134a, low GWP, and are inexpensive and plentiful.

R-513A and R-450A are HFC-134a replacements offered by Chemours and 

Honeywell, respectively, and could be used as medium-GWP interim steps towards the 

much lower GWP solutions provided by HFO-1234yf, HFO-1234ze, and the hydrocarbons.

However, in this application we believe it makes much more sense for manufacturers to 

skip the interim transition to R-513A and R-450A given the safe demonstration of 

hydrocarbons across the globe. 

Energy efficiency is important when selecting domestic refrigerator and freezer 

refrigerants, as over 98% of the life cycle carbon-equivalent emissions are from the fossil 

fuel and biomass used to generate electricity to power the appliance. Hydrocarbons and 

HFO-1234ze offer the clearest path to more efficient, low-GWP refrigerators, and a welltimed EPA HFC-134a delisting, alongside revisited charge limitations and safety 

mitigation, could facilitate this transition rapidly and at low cost to manufacturers. 

7. Remove R-410A from the list of acceptable substitutes in all new:

a. Portable factory sealed air conditioners and dehumidifiers effective 

January 1, 2019

b. Air-cooled centrifugal, screw, reciprocating, and scroll chillers effective 

January 1, 2019

c. Water-cooled centrifugal, screw, reciprocating, and scroll chillers 

effective January 1, 2023

d. Light commercial air conditioning effective January 1, 2023

e. Household residential split air conditioning effective January 1, 2025

NRDC and IGSD request that EPA defer consideration of the petition for those 

end-use sectors (7(d)-7(e)) that currently lack an approved low-GWP alternative until 

EPA has SNAP-approved a low-GWP alternative. 

NRDC and IGSD petition EPA to establish a comprehensive timeline for the phase 

down of R-410A. NRDC and IGSD request that EPA defer consideration of items 7(d) and 

7(e) until the first lower-GWP alternative is SNAP-approved in those end-uses. 

R-410A has replaced R-22 in almost all residential and medium-scale commercial 

comfort cooling applications in the US, bringing with it safety and stratospheric protection 

but also a dangerously-high GWP of 2088 and middling energy efficiency. Any 

international agreement to phase down HFCs will require strict controls on R-410A and 

EPA could demonstrate no greater leadership to the international community than by 

proposing such an R-410A ban. Furthermore, an EPA ruling on R-410A will address 
14

industry’s request for a firm timeline for phasing down those refrigerants, and is an 

absolute requirement for a second round of SNAP status changes.

Portable Factory-Sealed Products

The UL484 safety standard was recently updated to include Class 2 and Class 3 

refrigerants for use in factory-sealed portable appliances like small air conditioners, 

dehumidifiers and other similar devices. EPA’s Rule 19 provides additional options for 

refrigerants in this area. EPA has listed certain climate-friendly hydrocarbons (ethane, 

isobutane, and propane) and a hydrocarbon blend (R-441A) as acceptable in stand-alone 

commercial and household refrigerators and freezers, very low temperature refrigeration, 

non-mechanical heat transfer, vending machines, and room air conditioning units. EPA has 

also listed HFC-32 as acceptable in room air conditioning units—a two-thirds reduction in 

GWP from R-410A. EPA has also exempted ethane, isobutane, propane, and R-441A from 

the §608 venting prohibition for the specific applications listed above.

Chillers

Some chillers equipped with screw and scroll compressors use high-pressure 

refrigerant circuits that offer high cooling capacity. Generally smaller than medium- and 

low-pressure equipment, these units use R-410A with a GWP of 2088. The high GWP and 

prevalence of these chillers in US commercial buildings make R-410A a priority for 

removal from the list of acceptable substitutes. As such, NRDC and IGSD petition for the 

earliest-possible removal of these systems in commercial chiller applications. 

High-pressure alternatives HFC-32, R-454B, R-446A, R-447A, and “DR-55” have 

all been developed as medium-GWP replacements for R-410A. Daikin Industries and other 

Japanese manufacturers have championed HFC-32, a pure hydrofluorocarbon, for use in 

direct and indirect cooling applications. It offers a GWP of 675, 2L flammability, and high 

energy efficiency when optimized to the system design, but has higher discharge 

temperatures. Chemours’s R-454B, GWP 490, has been shown to have modest 

flammability and high energy efficiency, while their soon-to-be-numbered “DR-55” 

promises near-design-compatibility with R-410A, very low burning velocity, a GWP of 

675, and good energy efficiency. Honeywell has developed R-446A, GWP 490, and R447A, GWP 580, with emphasis on the same climate-friendly attributes and is currently 

implementing those refrigerants in Asia. 

SNAP has already included a 2L refrigerant in its list of acceptable alternatives for 

chillers, HFO-1234ze, which operates at medium pressure. As discussed in the previous 

section on chillers, the necessary standards updates for 2L-class air-cooled chillers are 

expected in 2016, while standards for 2L-class water-cooled chillers in mechanical rooms 

will be available in either 2018 or 2021. As such, NRDC and IGSD believe that the 
15

conversion away from R-410A is feasible for air-cooled chillers by 2019 and for watercooled chillers placed in mechanical rooms by 2023. Moreover, the proposal of this 

impending change of status will encourage ongoing efforts to clear regulatory hurdles 

regarding the adoption of 2L-class alternatives. 

The expected climate benefits of transitioning away from R-410A in chillers are 

two-pronged and very large. The reduction of GWP by at least a factor of three means 

significant direct emissions saving; moreover, 2L alternatives are typically more efficient 

than R-410A in native designs and have the potential to reduce use-phase electricity 

consumption. This life cycle benefit provides all the more reason to add R-410A 

alternatives to the SNAP list promptly and change the listing status of R-410A so that code 

organizations and industry know they can expect rapid, comprehensive transition of chiller 

refrigerants. 

Light Commercial and Residential A/C

Light commercial and residential air conditioning constitute a major subset of the 

heating, ventilating, and air conditioning (HVAC) sector and have also been dominated by 

R-410A since R-22’s phase out. These systems differ from chillers in that they directly 

condition air intended for space cooling, whereas chillers are indirect systems that cool 

water that will eventually be circulated through coils in the space. 

Commercial products included in this sector include rooftop air conditioning units 

and air handlers, while residential products include split systems, packaged central air 

conditioners, ductless mini-splits, heat pumps, and packaged-terminal air conditioners. 

There is also overlap between these two categories, as certain classes of residential 

products may also be used in small businesses or other light commercial applications. 

The alternatives being developed for these applications are the same as for chillers, 

and also offer the dual benefit of much-lower GWP and greater energy efficiency. NRDC 

and IGSD urge EPA to move forward expeditiously with the consideration of SNAP 

applications for the alternatives listed in the chillers section so manufacturers may begin 

preparing the transition. Such action, along with the changes of status proposed, will set the 

US on a path towards major HFC emissions reductions. 

ASHRAE 15 has established a subcommittee—ASHRAE 15.2—to determine 

safety standards for flammable refrigerants in residential applications. ASHRAE 15.2 

expects to complete its work by December 31, 2017, in order to be included in the 2021

International Residential Code published by the International Code Council for state and 

local government adoption. According to that schedule, residential standards will be 

finished well in advance of 2025, ensuring the widespread availability of systems using 

low-GWP alternatives before R-410A’s proposed change of status. 
16

For light commercial systems, the language developed by ASHRAE 15.2 for

residential products will likely be published into an updated ASHRAE 15, which has 

jurisdiction over all commercial refrigeration systems. While this process will likely follow 

the same 2021 code cycle timeline as residential applications, NRDC and IGSD believe 

that less time between code adoption and change of listing status is required for 

commercial applications. A change of status in 2023 reflects the U.S. Department of 

Energy’s estimate for refrigerant changeover used in setting efficiency standards for 

commercial unitary air conditioners (rooftop units).

8. Remove R-410A, R-407A, R-407C, and R-407F from the list of acceptable 

substitutes in all new and retrofit cold storage warehouses and industrial process 

refrigeration effective January 1, 2023. Remove R-410A, R-407C, and R-407F from the 

list of acceptable substitutes in all new and retrofit industrial process air conditioning 

effective January 1, 2023. 

As discussed in the previous section, the R-410 and R-407 refrigerants will be 

supplanted by available alternatives starting widely in 2021. NRDC and IGSD petition that 

they be removed categorically from industrial and cold storage applications in 2023 in light 

of the availability of suitable alternatives. In addition, currently-existing alternatives like R717 and R-744 allow this transition to begin even sooner if site-specific design concerns 

allow. 

9. Restrict the sale of small canisters of HFC-134a to certified technicians 

only, effective January 1, 2017. 

Small can sales of HFC-134a to uncertified do-it-yourself users have been a major 

source of emissions as long as HFC-134a has been used in MAC systems. As noted in 

previous petitions, half of HFC-134a sold for MAC professional service maintains 90% of 

vehicles requiring service. The other half is sold to do-it-yourself users who account for 

10% of all MAC systems. 

While closing this gap would constitute a major emissions savings on its own, an 

even greater environmental risk has emerged. As industry shifts to HFO-1234yf MAC

systems to comply with EPA’s delisting of HFC-134a in new vehicles starting model year 

2021, the opportunity will arise to user-recharge an HFO-1234yf MAC system with HFC134a. Small cans of HFC-134a are expected to be ten times less expensive than the cost of 

an HFO-1234yf recharge, an incentive more than sufficient to make this loophole a major 

climate concern. For example, a small can of HFC-134a with a retail price of $20 contains 

about $4 of refrigerant, but would have a retail price of at least $60 with HFO-1234yf 

costing $54 for the same amount. As such, restricting the sales of HFC-134a small cans has 

significant climate benefit and will ensure that EPA realizes the emissions savings 

estimated in the light-duty vehicle HFC-134a delisting. 
17

10. Reference international standards IEC 60335-2-40 and ISO5149 when 

granting SNAP approval for new alternatives in the end uses covered by those standards. 

NRDC and IGSD petition EPA to reference international design standard IEC 

60335-2-40 and international use standard ISO 5149 when adding lower-GWP alternatives 

to the SNAP list. IEC 60335-2-40 and ISO 5149 are international standards developed with 

US participation and reflect an international perspective on design and use standards for 

HVAC equipment and refrigerants under consideration by SNAP. 

Referencing these standards will allow EPA to consider new SNAP applications for 

low-GWP, 2L-class alternatives without waiting for the ASHRAE standards development 

process to finish, which may take until 2018. EPA can use these international standards as 

a baseline for the use conditions placed on alternative refrigerants and then focus their 

independent risk analysis efforts on areas relevant specifically to US applications. 

11. Remove HFC-134a, HFC-245fa, HFC-365mfc and HFC-227ea from the 

list of acceptable substitutes in rigid polyurethane spray foams effective January 1, 2017. 

NRDC and IGSD commend SNAP on their comprehensive action on high-GWP 

foams in the first change of status rule. One additional end-use—rigid polyurethane spray 

foams—should see additional changes of status for HFC-134a, HFC-245fa, HFC-365mfc, 

and HFC-227ea. Rigid polyurethane spray foams are used as insulation for homes and 

buildings and can be made with alternatives HFO-1233zd and HFO-1336mzz. Both 

alternatives offer very low GWP and practically equal insulation properties to those being 

replaced. 

Industry has indicated that they can commercialize low-GWP alternatives within six 

months once SNAP regulations require it. In addition, Honeywell is expanding its current 

plant and bringing another plant online in 2018, while Chemours is also pursuing increased 

production capacity. Spray foam customers and suppliers need a strong signal to begin the 

transition and SNAP should provide it on a similar timeline to the changes of status 

finalized for the rest of the foams sector. 

* * *

NRDC and IGSD believe that action on the petition items above will put the United 

States in a strong position regarding both domestic and international efforts to phase down 

HFCs. In order to maintain each step of the HFC phase-down timeline put forth by the 

North American proposal to amend the Montreal Protocol, additional SNAP changes of 

status will be required. By 2019—the first proposed year of control—additional bans will 

be required to achieve the US’s targeted consumption reductions. NRDC and IGSD view 

the above bans on HFC-134a, R-404A, and R-507A as a significant step towards hitting the 
18

US’s first control year goal and believe they will send a strong international message of 

leadership. Further delisting of R-410A will show that the United States is capable of deep 

HFC consumption reductions in the near future and is committed to leading the way 

towards an HFC agreement under the Montreal Protocol. 

Sincerely,

David Doniger

Ben Longstreth

Emily Davis

Alex Hillbrand

Climate and Clean Air Program

Natural Resources Defense Council

1152 15th St. NW

Washington, D.C. 20008

ddoniger@nrdc.org

blongstreth@nrdc.org

edavis@nrdc.org

ahillbrand@nrdc.org

Durwood Zaelke 

Stephen O. Andersen

Nancy Sherman 

Institute for Governance & Sustainable Development

2300 Wisconsin Ave. NW Suite 300B

Washington, D.C. 20007 

zaelke@igsd.org

soliverandersen@aol.com

nsherman@igsd.org
19

 i U.S. EPA, Stratospheric Protection Division, Office of Atmospheric Programs, 

Benefits of Addressing HFCs under the Montreal Protocol, pg. 2 (June 2013) available 

at Memorandum to Docket: References and Associated Documents, Docket No. EPAHQ-OAR-2014-0198-0003. [hereinafter “Benefits of Addressing HFCs”].

ii Id. at 11. 

iii Environmental Protection Agency, Significant New Alternatives Policy (SNAP) 

Program, http://www.epa.gov/ozone/snap/index.html (last visited Sept. 18, 2015)

iv Id.

v Significant New Alternatives Policy Program, Purpose and Scope, 40 C.F.R. § 82.170 

(2015).

vi Significant New Alternatives Policy Program, Agency Review of SNAP Submissions, 

40 C.F.R. § 82.180(a)(7)(i)-(ii) (2015).

vii Protection of Stratospheric Ozone; Request for Data and Advanced Notice of 

Proposed Rulemaking, 57 Fed. Reg. 1984, 1985 (Jan. 16, 1992).

viii Some bans are proposed under the assumption that soon-to-be-available 

refrigerants will be SNAP-approved in that application. 

ix U.S. EPA, Protection of Stratospheric Ozone: Change of Listing Status for Certain 

Substitutes under the Significant New Alternatives Policy Program, 80 Fed. Reg. 

42,870 (July 20, 2015) (Docket ID No. EPA-HQ-OAR-2014-0198-0238) x http://conf.montreal-protocol.org/meeting/workshops/hfc_management02/presession/PreSession%20Documents/FS%205%20Industrial%20Refrigeration%20f

inal.pdf

xi Low-GWP Chillers Development Update. Dr. Nacer Achaichia, Honeywell. 2014. 

xii There may be limited exceptions for unique situations such as military vehicles 

where even mildly flammable refrigerants may not be acceptable 

xiii Fact Sheet 3: Domestic Refrigeration. UNEP Ozone Secretariat. 21 April, 2015.