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Federal Register / Vol. 86, No. 86 / Thursday, May 6, 2021 / Rules and Regulations
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a. Substitutes and End-Use Proposed Comment: Several commenters voiced general support for the proposed listing of HFC32, R452A, R454A, R454B, R454C, and R457A as acceptable subject to use conditions in residential and light commercial air conditioning and heat pumps. Chemours likewise supported the proposal. Daikin voiced strong support and encouraged EPA to approve HFC32 quickly, noting that over 100 million R32 split system air conditioners have been sold since 2012 and provided a list showcasing their and other manufactures implementation of air conditioning products using A2L refrigerants in other countries. HARDI supported these listings as one part of a larger process in the industrys effort to phase down older refrigerants.
Response: EPA acknowledges these commenters general support for this proposed listing and appreciates the additional information provided by Daikin on the use of HFC32. We add to that information that it has been reported that products using HFC32
are operating in over 90 countries.34
After considering all the public comments on this proposal, we are finalizing this portion of the rule as proposed with only a few modifications discussed elsewhere in this final rule.
b. Clarifications Comment: AHRI suggested that rather than mildly flammable refrigerants EPA use the term refrigerants with lower flammability to remain consistent with ASHRAE classifications.
Response: EPA acknowledges this correction and has used the lower flammability description for the A2L
refrigerants in the preamble to this final rule. In the Further information column of the regulatory text in this final rule, we have used the term Flammable to replace the term Mildly flammable that was contained in the 2020 NPRM.
Comment: AHRI pointed out that EPA
indicated class 2L flammability is determined based on testing at 73.4 F
23.0 C. They noted that ASHRAE
Standard 342019 requires testing at that temperature to determine if flame propagation exists and if not, tests at 140 F 60 C are conducted to determine the refrigerant flammability classification.
Response: EPA acknowledges this clarification, which is incorporated in 34 The Air Conditioning, Heating, and Refrigeration News, An HVAC Technicians Guide to R32, November 12, 2020. Available at https
www.achrnews.com/articles/144053-an-hvactechnicians-guide-to-r-32?oly_enc_
id=8731J4776701J6C.

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the description of the ASHRAE standard testing procedures to determine flammability classification in section II.B.3 above.
Comment: AHRI provided additional detail on requirements contained in UL
60335240 and stated that some of the summary information EPA provided 85
FR 3588434885, June 12, 2020 may be taken out of context or be incorrect. For instance, they stated alarms might not be required for most systems and if refrigerant concentrations are found to exceed certain thresholds a mitigation strategy such as fan operation and air circulation or ventilation would be activated; shut-off valves are only an option for VRF systems; connected space requirements exist for duct-free equipment but are not required for ducted systems with sensors/detectors;
mitigation requirements for labeling, ignition source controls, and other features are required for portable appliances with charge sizes less than three times the LFL; that similar requirements exist for fixed appliances where the charge is less than six times the LFL; that detectors are required to be factory installed, qualified and listed with the product for equipment above a charge size calculated per the standard;
outdoor air ventilation is required only in a few cases; and while Annex HH is informative as EPA stated in the proposal, installation and service instructions are required by the UL
standard and that these instructions would tailor Annex HH
recommendations to the specific product. Carrier pointed out that Annex DD of the standard, while also informative, provides guidance on what information should be included in operation, service and installation manuals.
Response: EPA acknowledges these clarifications and we agree with the commenters more detailed characterization of certain aspects of UL
Standard 60335240. Our description in section II.B.5 above is offered only for informational purposes and is not meant to be an exhaustive summary of the standard. We emphasize that our use conditions are not reliant on that informational description but rather adherence to the actual requirements in the standard, which is incorporated by reference in this rulemaking.
Comment: AHRI stated that the proposed rule would require the use of spark-free equipment but states such tools are not required for A2L
refrigerants as these refrigerants have a high minimum ignition energy and sparks from tools and even some electrical devices is not a competent ignition source for an A2L refrigerant
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due to their higher minimum ignition energies.
Response: EPA noted in the proposal and reiterates in this final rule that the information on spark-free tools is included in the Further information column of the regulatory text and so is not a requirement of the rule. While we believe the use of spark-free tools provides additional risk mitigation for technicians working with flammable refrigerants, it was not proposed as a requirement and in this final rule we maintain the recommendation in the Further information column.
c. Use Conditions i. Standards Comment: Daikin supported EPAs reliance on UL Standard 60335240 as a basis for listing as acceptable with a use condition requiring adherence to that standard. NRDC, speaking in part about the UL Standard, stated that EPAs approach of reviewing, adjusting as needed, and then adopting these standards safe use requirements is sound.
Response: EPA acknowledges Daikins and NRDCs support for these aspects of the proposed listing. After considering all the public comments on this proposal, we are finalizing this listing, as described in section II.B, including the use conditions related to UL 60335
240.
Comment: Pointing to ASHRAE 15
2019 and the third edition of UL 60335
240, Chemours stated that the application and product standards for the end-uses referenced in the proposed rule are complete. AHRI stated that industry has proposed requirements to reduce risk with A2L refrigerants in UL
Standard 60335240, ASHRAE
Standard 15, and ASHRAE Standard 15.2. They provided some examples of these including air circulation as well as control of ignition sources and hot surface temperatures. Trane stated EPAs use conditions should be linked to the current and future versions of ASHRAE 15 and ASHRAE 15.2, the latter of which they expected to be published in early 2021. They noted that these standards govern the installation, operation and maintenance of heating, ventilation, and air conditioning HVAC systems using A2L
refrigerants in commercial and residential occupancies.
Response: EPA understands that other risk mitigation requirements have been proposed by the standards project committee for ASHRAE 15 and ASHRAE 15.2 and may be used by the HVAC industry, just as mitigation requirements have already been
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