## Summary of Interagency Working Comments on Draft Language under EO

12866 and EO 13563 Interagency Review. Subject to Further Policy Review.

Interagency Comments on U.S. Environmental Protection Agency (EPA) draft final rule titled,

“ Protection of Stratospheric Ozone: Proposed New Listings of Substitutes; Changes of Listing Status; and Reinterpretation of Unacceptability for Closed Cell Foam Products under the Significant New Alternatives Policy Program; and Revision of Clean Air Act Section 608’s Venting Prohibition for Propane ,” (RIN 2060

‐ AS80 )

1. From the commenting agency’s perspective, this rule is a very helpful driver in our efforts to secure an HFC amendment in 2016 by showing that HFC alternatives are available, and that the US is delivering domestically to reduce HFC use and emissions. This rule would significantly he lp the negotiations if the proposal is out by mid

- March, this would be far enough in advance of the April 4

- 8 Open

- ended working group meeting that other countries would be aware of it and we can speak to the proposal at the meeting. Second, the commentin g agency would ask that we make utmost efforts to finalize the rule by mid

- September, in advance of the October 10

- 14 Meeting of the Parties where the commenting agency hopes to adopt an HFC amendment.

EPA Response : We appreciate the commenter’s perspecti ve and agree that there is value in issuing the NPRM ahead of the April 4

- 8 OEWG meeting. It would provide an opportunity for the United States to demonstrate the actions we are taking domestically. We also see the value in issuing the final rule ahead o f the October MOP.

2. Has EPA considered including window air conditioning units? Or are there other categories of equipment that EPA thinks should be included as well?

EPA Response : EPA has reviewed the SNAP end

- uses considering the overall risk to human health and the environment of the various acceptable alternatives and knowledge of the availability and deployment of equipment using alternatives that pose lower overall risk. For window air conditioners, in April 2015, EPA found HFC

- 32, R

- 290 and R

- 441A acceptable subject to use conditions. We are not aware of any such units being sold in the U.S. market currently. Furthermore, recent changes in the UL Standard covering such products have placed on these acceptable refrigerants requirements that are stric ter than the use conditions EPA established. The UL Standard effectively limits use of these flammable refrigerants to a small subset of room air conditioners. Because we have no evidence that alternatives have been identified that are viable for these u nits, EPA considers it premature to propose that other alternatives that pose lower risk are available in this end

- use.

Lower

- GWP refrigerants are acceptable in other end

- uses; however, similar to window air conditioning units at this time we do not ha ve evidence that those alternatives are viable for those particular end

- uses. EPA will continue to study those end

- uses and the availability of alternatives that pose lower overall risk to human health and the environment for possible changes of status in the future.

3. Table numbers refer to tables in the screening analysis for the following comments:

a. Aggregation in the screening analysis

- EPA should not be considering the aggregated impacts on small entities to support its RFA certification. This rule is a series of separable provisions that do not interact with each other, so aggregation masks signif icant economic effects. In particular, working from table 19 of the screening2 analysis, if considered separately, two of the product/uses regulated here appear to lead to significant economic impacts on a substantial number of small entities.

EPA Respons e : Per EPA’s “Final Guidance for EPA Rulewriters: Regulatory Flexibility Act as amended by the Small Business Regulatory Enforcement Fairness Act” (2006), EPA makes a certification of no SISNOSE for a rule as a whole (i.e., aggregates across industries and or types of small entities). EPA does not make separate certifications for separate provisions of a single rule, even if the provisions are separable.

b. Annualization in the screening analysis

- While annualization may be appropriate in
cost

- benefit analys es, it should not be used in screening analyses. Annualization assumes that a small business can effect a loan for the purposes of regulatory compliance at a rate of 7% over the annualization period. (In one case, EPA uses 20 years. In another case, it us es 25 years. Neither would be available to a small business, even for productive investment in facilities.) Please express compliance costs in terms of capital (or one

- time) costs and operating costs to help evaluate the likely economic impacts.

EPA Res ponse : EPA’s “Final Guidance for EPA Rulewriters: Regulatory Flexibility Act as amended by the Small Business Regulatory Enforcement Fairness Act” (2006) specifically states that “annualizing the compliance costs is appropriate when a stream of cash flows or a large capital expenditure is involved with compliance (see section 2.6.2 on p.20).

c. Energy Efficiency Standards

- The interaction between the DOE energy efficiency standards and this proposed rule are more significant than discussed and has the potent ial to significantly increase costs. It appears that the cost estimates in the screening analysis assumes that replacement with 450 and 513 will have no energy efficiency impacts. Are there any other sources for the assertion that 450 and 513 are drop

- in replacements that require no upfront re

- engineering or changes to maintain energy efficiency?

EPA Response : EPA noted in SNAP Rule 20 that R

- 450A and R

- 513A were specifically designed to be a very close match in the properties and performance of HFC

- 134a . As such, EPA does not believe that the energy efficiency of a given unit will be significantly impacted by the choice of these refrigerants. Because the changes of status proposed here only affect new equipment, manufacturers will have ample opportunity to assess and, if desired, improve the efficiency of equipment using these alternatives. In fact, the similarity with HFC

- 134a is so good that manufacturers are currently offering equipment that are equally rated for either refrigerant (e.g., for chillers dual

- rated for HFC

- 134a and R

- 513A, see http://www.trane.com/commercial/europe/be/en/about

us/newsroom/press

- releases/trane

- sintesis.html and https://www.chemours.com/Refrigerants/en_US/assets/downloads/20160120

- press

release

- johnson

- controls

- opteon

- xp10.pdfu ).3 For small entities, a short gap between energy efficiency standards and SNAP standards means that they either have to go through two engineering cycles on their products in a very short period of time or their compliance date for SNAP would, in effect, be the earlier date for energy efficiency standards. If the practical effect of the two rules together is an earlier compliance date, how does that affect EPA’s finding that there is enough time to meet the technical challenges of adopting substitutes? If en gineering for both regulation has to be combined, then it would increase the costs.

EPA Response : Although EPA works under authorities different than DOE, and therefore our status change dates may differ from DOE compliance dates, EPA has considered the D OE energy conservation standards as part of our analysis of when products using alternatives may be available, and has proposed status change dates considering those standards. For those products that fall under DOE energy conservations standards (e.g., ho me refrigerator

- freezers, some refrigerated food processing and delivery equipment, some equipment types applied in cold storage warehouses), EPA has considered the existing and likely future cycles of DOE standards, and believes the status change dates we have proposed line up reasonably well with DOE compliance dates. This will allow manufacturers to choose whether they wish to meet the two regulations in series

— in which case the costs estimated by EPA would apply to meeting our proposed regulation

— or whe ther they want to reduce costs by meeting them in a combined fashion. We expect that updated information regarding the DOE standards will become available during the comment period on the proposed rule and we will consider that information along with comme nts on this issue as we develop the final rule.

d. Cold Storage

– The commenter has concerns about the certification for this sector. This section leaves the impression that the universe of small entities that produce packaged systems with fluorinated refrig erants would be significantly affected (i.e

. , 4 of 4). Table 19 implies that all four of these entities would experience a significant economic impact. Advocacy encourages EPA to consider alternatives that would significantly reduce the burden on these f

our entities.

EPA Response : While EPA agrees it is appropriate to analyze impacts on different industries separately in order to consider alternatives that may alleviate some impact for sectors or industries where impact is greater, for purposes of certif ying no SISNOSE, impacts of a rule are aggregated across sectors/industries/type of entity, and the certification decision is based on the aggregated impact (see section 2.7.3, pp.26

- 28). EPA does not make certifications by sector.

e. Spray

– The commenter has significant concerns about the certification for this industry. Even though the number of small entities in the NAICS code is several hundred, the whole NAICS code is not the appropriate number against which to compare for the purposes of determining a “substantial number.” Considered as a separable part of this rulemaking, table 19 would imply that almost half of the small entities affected would4 experience significant impacts. Since these impacts are presented as annualized over 25 years, this may b e a significant understatement of costs.

EPA Response : EPA has not compared the number of affected small businesses against all small businesses in the whole NAICS code. While EPA agrees it is appropriate to analyze impacts on different industries separat ely in order to consider alternatives that may alleviate some impact for sectors or industries where impact is greater, for purposes of certifying no SISNOSE, impacts of a rule are aggregated across sectors/industries/type of entity, and the certification decision is based on the aggregated impact (see section 2.7.3, pp.26

- 28). EPA does not make certifications by
sector.

f. Repair and Maintenance

- I’m not completely sure how this rule would impact repair and maintenance of equipment manufactured before the e ffective dates. Would a partial replacement of refrigerator parts and recharge with phased out HFC still be allowed? How are these service providers regulated? Are there any estimates of the size of this kind of repair market and the extent to which it ext ends the useful life of regulated products?

EPA Response : This rule would not impact repair and maintenance of equipment manufactured before the effective dates. As in the previous rule for change of status of certain substitutes, equipment manufactured before the change of status dates may continue to be serviced with the refrigerants undergoing a change of status. The
propos ed change of status would apply only to newly manufactured equipment.

4. The commenter conducts research and operations across a wide spectrum of technical areas and levels of readiness. In general, the commenter uses HFCs as replacements for ozone

depleting substances (ODSs) in numerous applications, including certain mission

- critical applications for which appropriate substitutes hav e not been identified. These uses can include precision cleaning, foam blowing, and possibly other applications. Because of the dynamic nature of our Agency’s work, particularly as regards space flight programs currently being developed, it is not possib le to identify all possible mission

- critical uses of high

- GWP substances, even the limited subset of materials and applications addressed in the proposed Significant New Alternatives Policy (SNAP) Program rule.

Two proposed provisions are of particular co ncern, as detailed below.

a. Extension of the proposed narrowed use limit for spray foams by three years, to expire on January 1, 2025. EPA is proposing to list as unacceptable several HFC and HFC blend foam blowing agents for certain spray foam applicati ons. EPA is also proposing an exception to this listing for military or space

- and aeronautics

- related applications when used in low pressure two

- component and high pressure two

- component spray foams. This exception would be a narrowed use limit expiring on January 1, 2022.5 As currently written, th e proposed rule would allow the commenting agency to use through Calendar Year (CY) 2021 mission

- critical HFC 245fa

- based cryoinsulation spray foams being qualified for use on space flight hardware. These foams replace HCFC 141b

- blown foams, which in turn replaced CFC 11

- blown foams in similar applications. Each of these successive foam replacement efforts took several years due to the challenging operational environment and the lengthy requalification process associated with human rating. The commenting agency has begun planning a research program for our human

- rated systems that would screen numerous foam chemistries as possible substitutes. However, since no single chemistry has yet been identified that can meet the rigorous technical and safety requirements of human

- rated space flight systems, it could take several years to complete replacement work. Considering the length of the federal budgetary cycle and the length of time the commenter anticipate s bein g needed to identify, develop, test and implement substitutes, the commenter does not expect to be able to deploy replacement foams in the proposed timeframe. Although the commenter is not certain how much time will be required for substitution work, the
commenter believe s an additional three years for this narrowed use limit should be adequate.

EPA Response : EPA agrees. We appreciate the additional information on specific steps required for military or space

- and aeronautics

- related applications. We will revise the discussion in the preamble to allow until January 1, 2025 for those applications under the narrowed use limit.

b. Exemption of spaceflight hardware and related support equipment from the proposed import ban on products composed of or incorporating closed cell foams made with unacceptable blowing agents.

EPA is proposing to apply the unacceptability determinations in this action for foam blowing agents, as well as all listings for foam blowing agents codified in the appendices to 40 CFR part 82 sub part G, to closed cell foam products and products containing closed cell foam. This would mean that closed cell foam products and products containing closed cell foams manufactured abroad and imported could not be used in the United States if the foam blow ing agent was listed as unacceptable.

The commenting agency uses parts and components made abroad to meet challenging mission requirements and, in some cases, as part of international agreements with partners such as Japan, Canada, Russia, and the Europea n Union. These components may comprise or incorporate closed cell foam products or products containing closed cell foams made with blowing agents listed as
unaccep table. It is critical that the commenting agency be allowed to use parts and components tha t are qualified for spaceflight applications to minimize risk to our crews, vehicles and overall mission.

We request that EPA consider exempting spaceflight hardware and related support equipment from this proposed provision. This would allow continued u se of parts6 and components needed for mission safety and to meet th e technical requirements of the commenter ’s partners.

In addition, NASA has reviewed the recently updated draft language providing “narrowed use limits for military or space

- and aeronauti cs

- related applications” through CY 2024 for certain refrigerants used in centrifugal chillers and positive displacement chillers. We concur with this updated draft language.

EPA Response : In response to the commenting agency’s request, we are proposing to revise the change of status date from January 1, 2022 to January 1, 2025 when HFCs become unacceptable in foam blowing end

- uses for space and aeronautic

- related uses. This will provide ad ditional flexibility to the commenting agency for all foam blowing end

- uses. For space and aeronautics

- related uses, t he extension of unacceptability determinations to foam products containing the unacceptable foam blowing agent would apply only to product s manufactured after January 1, 2025.

5. Much of the supporting analysis referenced by EPA as contained within contracted research reports was not available to the commenting agency and thus, we were unable to determine the underlying assumptions that went i nto t he analysis. From the commenting agencies’ perspective, there are several areas where it appears (under cursory review) that the occupational exposure perspective may have been insufficiently and/or inappropriately considered. For example:

a. In man y instances, the EPA analysis relies on AEGL values for short

- term exposure and does not use NIOSH IDLH values. This occurs in both occupational and non

- occupational analysis but given that many workers commute or work in affected vehicles for significant time periods, th e “consumer” analysis needs to also consider occupational exposure criterion.

EPA Response : It is not clear which substitute or end

- use the comment pertains to. We are unaware of a NIOSH IDLH value for HFO

- 1234yf or 2

- BTP. In the case of propane, EPA initially considered using the IDLH value of 2,100 ppm (30

- minute TWA), but decided not to use the IDHL because it is based upon flammability concerns (i.e., set at 10% of the lower explosive limit of 2.1%). Instead, we decided to use the AEGL

- 1 (30

- min) in our analysis of toxicity of propane because the AEGL

- 1 is based on toxicity information. Furt her, the AEGL

- 1 value is appropriate for the general population. For ice machines and water coolers, the end

- use analysis considers scenarios where a consumer could be exposed as well as a worker (e.g., ice machine used in a restaurant). EPA has analyzed f

lammability concerns separately from toxicity based upon an instantaneous release of refrigerant rather than upon a 30

- minute TWA exposure, such as would be needed to compare to a 30

- minute TWA IDLH.

3/17 Interagency Follow

- up Comment : When discussing a lternatives solely from a toxicity perspective

– we concur with this approach. Th e end

- use analysis details are not available to the reviewers and is only7 loosely referenced in the NOPR. It is not clear if commercial

- sized refrigeration and ice making eq uipment were evaluated under non

- restaurant scenarios such as in a small bar that may not have a kitc hen hood exhaust. If not considered, then further analyses should be performed since such higher charge s , lower ventilation rate scenarios could alter the model outcomes.

EPA Response : 

### EPA will take comment in the preamble on the risk screens, their assumptions, and the exposure limits used in our evaluation.

b. EPA’s occupational exposure analysis was consistently limited to service technicians and apparently did not consider the potential occupational exposures that could result to workers in numerous industries affected by the proposed rule, but most notably workers in transportation, public (to include fire/rescue/police), healthcare and service

s ectors.

EPA Response: The only workers that normally would work directly with refrigerant would be technicians or individuals who evacuate refrigerant from the equipment during recycling or disposal, and EPA analyzed both of these situations under the des cription of “occupational exposure.” However, EPA also evaluated exposure in the case where there is a leak from the equipment while it is in use. In these analyses, EPA considered consumer exposure and personnel exposure, such as to a restaurant worker

wo rking near a commercial ice machine or water cooler or a laboratory worker working near a very low temperature freezer. For use of HFO

- 1234yf in motor vehicle air conditioning, EPA considered exposure to professional technicians, vehicle occupants, and fir st responders (i.e., fire/rescue/police). EPA looked at both exposure to the refrigerant itself as well as exposure to potential combustion byproducts (p.171

- 172 & 176 of the preamble) and concluded that HFO

- 1234yf does not pose greater risk with regard to HF generation than other available or potentially alternatives, including risk to workers.

c. When considering flammability issues, they rely on Lower Flammability Levels (LFL) (and apparent assumptions of even mixing throughout spaces) as opposed to the
tr aditional 10% of Lower Explosive Limit (LEL) criteria.

EPA Response: EPA’s SNAP program has traditionally analyzed flammability risks by considering an instantaneous release of the substitute and comparing it to the lower flammability limit (LFL). We sta rt by assuming that refrigerants that are denser than air, such as propane, will pool near the floor, and that 95% of the refrigerant charge will be in the lowest 0.4 m (1.3 ft) of a room. We also look to available literature for conservative but reasonabl e assumptions about ventilation rates, as well as using available information on room sizes and charge sizes. If a substitute’s instantaneous concentration exceeds the LFL, then we reconsider the conservativeness of the assumptions, and may consider situat ions where complete mixing is reasonable (e.g., if building codes require a certain ventilation rate).8 EPA understands that NIOSH has sometimes used a value of 10% of the LEL when establishing 30

- minute IDLH values for the workplace for certain highly flammable substances (e.g., propane). However, we are unfamiliar with risk assessments of specific situations that use such a criterion. It is also our understanding that OSHA regulations require concentrations of flammable substances be kept to no more th an 25% of the LFL in the workplace. Thus, we do not agree that there is a “traditional” value used throughout the federal government for addressing and assessing flammability risks.

3/17 Interagency Follow

- up Response to first paragraph: Under still air conditions this seems plausible

, but in semi

- confined environments where this equipment is often placed, (often more than one piece at a time) with fan

induced airflows and hot equipment whose heat exchangers induce convective heat rise,

a still

- air assumption is probably not practical. Under these scenarios, room sizes and room ventilation rates may often be disassociated with gas behavior near the equipment. These scenarios should be investigated using actual experimental results as
oppo sed to theoretical models that require generalized input assumptions.

Regarding “ If a substitute’s instantaneous concentration exceed the LFL... ”: From a human safety perspective, the LFL itself is not an acceptable pass/fail criterion for potential flammab le environments.

It is important to note that a NIOSH IDLH value is not a 30

- min ute time

- weighted average (TWA). It is a ceiling value that represents a concentration for which “ EVERY EFFORT SHOULD BE MADE TO EXIT IMMEDIATELY” (emphasis not added by

re viewers) Please see: http://www.cdc.gov/niosh/npg/pgintrod.html

3/17 Interagency Follow

- up Response to second paragraph : We concur with the EPA ’s comment that the 10% of LEL criterion by itself is not the sole “traditional” criterion for determining when an environment potentially exposed to flammable vapors is “safe”. In hindsight, we should have said, “...as opposed to the traditional 10% or 25% of Lower Explosive Limit (LEL) safety criteria for p otentially flammable environments that is cited by NIOSH, OSHA and NFPA .” Either of these criterion however, are a much more realistic safety concentration target than the current NOPR’s use of 100% of the LFL as the safe threshold.

Regarding the EPA r esponse sentence “ It is also our understanding that OSHA regulations require ...” :
1) OSHA defines Hazardous Atmospheres as including “Flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL)

. ” http://webapps.dol.gov/elaws/osha/confined/definitions.asp#hazardous

.9 2) There is logical basis within NFPA (and by ref, some OSHA codes) to use the 25% of LEL for non

- confined areas. Either of t hese options (10% or 25%) are a much safer alternative for a pass/fail criterion than the LFL itself.

EPA response : 

### EPA will take comment in the preamble on the risk screens, their assumptions, and the flammability limits used in our evaluation.

d. EPA needs to add minimum enclosure volume requirements as a proposed use condition for placement of new equipment that uses flammable refrigerants. Ice machines, vending machines and water coolers are often placed within custom wall cubicles that would ex acerbate the flammability hazards associated with potential leaks and these size restrictions do not appear to have been adequately considered within EPA’s analysis.

EPA Response : Rather than proposing to add a use condition, EPA will take comment in th e preamble on the risk screens and their assumptions. Based on currently available information, we think that the room sizes used in our risk screen indicate there would not be an unacceptable risk of fire or explosion provided that the charge size is limi ted to 150 g. However, if further information becomes available during the public comment period that might cause us to change our assumptions, we may consider setting a use condition.

3/17 Interagency follow

- up comment : We appreciate the concurrence. U pon additional reflection, the minimum enclosure volume requirements should also probably be based on a “per piece of equipment” ratio since many such areas could have multiple pieces of equipment using the same refrigerant.

Given these assumptions, sq

- ft of floor area seems to be a more applicable criteria than room volume. Nevertheless, our calculations

, following the EPA

- provided assumptions

, determined that this may not be a sufficiently large space. (Please see sample calculation for m inimum r oom v olume below )”.

Regarding “

... or at least 15 m 3 for equipment with a charge of 100 g or less ,” similar concerns exist for this Room volume: charge size ratio as to those stated immediately above

Sample Calculation for Minimum Room Volume (Floor Area) Disc ussion: Given: (1) EPA/NOPR proposed limit of room volume of 22 m3 (2) EPA/NOPR assumption that 95% of propane charge will settle in lowest 0.4 meters of
floor area (3) LEL for propane = 21000 ppm (NIOSH pocket guide

- http://www.cdc.gov/niosh/npg/npgd0524.html ) (4) 1 ppm propane/air = 1.8 mg/m3 propane/air (NIOSH pocket guide)10 Assumption: (1) Room height in EPA/NOPR proposed room volume is 2.44m (8’) [Note: A taller room height would be an even worse scenario)

C alculations: (1) Floor area = V/h = 22 m 3 / 2.44m = 9m 2 (2) Vol of propane

- contaminated atmosphere = 9m 2 x 0.4m = 3.6 m 3 (3) 95% of 150g charge = .95x150x1000 = 142500 mg of propane (4) Conc of propane in lower rom volume = 142500 mg/ 3.6 m3 = 39583 mg/m 3 (5) 39583 mg/m 3 / ((1.8 mg/m3)/ppm) = 21991 ppm of propane**

** This value is above the LEL for propane, over 4 times the 25% of LEL (5250 ppm) criterion and over 10 times the 10% of LEL criterion. The NIOSH reviewers recommend that the minimum floor volume per piece o f propane refrigerant equipment be increased to at least comply with the 25% of LEL criterion. However, even this increase may not be sufficient (see additional comment below). Additional Comment : While it is an informative exercise, a potential fault in this approach is the assumption that the propane will dissipate across the entire floor area. As we know, this equipment tends to be placed into wall cubicles, under countertops, between cabinets and/or between other pieces of equipment (that may not h ave similar UL protections as the refrigeration compressors that use flammable refrigerants). Under these real

- world installation conditions

– the resulting propane concentration under the identified release scenario would be even higher and a serious pot ential hazard given all of the ignition sources in these areas.

EPA Response : EPA will take comment in the preamble on the risk screens and their assumptions.

e. Combustion byproduct analysis for HFO

- 1234yf only focused on hydrogen fluoride whereas recent research (( http://www.en.uni

muenchen.de/news/newsarchiv/2014/kornath_refrigerant.html ) seems to indicates carbonyl fluoride (much more toxic) should also be considered.

EPA Response : The amount of carbonyl fluoride produced when HFO

- 1234yf decomposes or burns is small and is comparable to that for HFC

- 134a. For both compounds, carbonyl fluoride quickly reacts with moisture and decomposes to HF and CO 2
.

f. In the combustion byproduct analysis, AEGL values were again referenced for potential occupational exposure scenarios where ILDH values are more applicable and in this case, would likely have led to a different conclusion.

EPA Response : Exposure to combus tion byproducts of HFO

- 1234yf is anticipated to occur only when the refrigerant combusts and the combustion byproducts are carried into the passenger cabin. If a driver or passenger is in a vehicle with a fire under the hood and is exposed to smoke and the byproducts of combustion of refrigerant, he or11 she is likely to exit the vehicle as quickly as possible, and certainly in far less than 30 minutes. Thus, a higher AEGL

- 2 value of 95 ppm over 10 minutes is more applicable, rather than a longer

- term, lower exposure limit for HF such as the IDLH of 30 ppm over 30 minutes or the AEGL

- 2 of 34 ppm over 30 minutes.

3/17 Interagency follow

- up comment:

Regarding “ likely to exit the vehicle as quickly as possible...”: assumes that the person is able to exit, which is often not the case.

“ ...a higher AEGL

- 2 value of 95 ppm ...”: NIOSH Recommended Exposure Limits ( RELs ) for hydrogen fluoride include a 15

- min ute ceiling of 6 ppm (same as the OSHA STEL) and an IDLH value of 30 ppm. As ind icated in our other responses, t he IDLH value is NOT a 30

- min ute TWA
, but rather is an exposure value that should result in immediate evacuation. (Please see NIOSH Pocket Guide entry: http://www.cdc.gov/niosh/npg/npgd0334.html )

.

It is noted that in the two EPA

- cited experimental investigations (see next comment) of potential hydrogen fluoride exposures in the cab of a vehicle, the above

- mentioned HF concentration values (6 ppm & 30 ppm) were exceeded in both experiments, and significantly so in 1 of 2 of the experiments

.
EPA Response : This section is a reference to risk assessment work performed by a cooperative research program (CRP) of SAE International, an international standard

setting body. We have relied upon this work in EPA’s earlier listing of HFO

- 1234yf for light

- duty passenger vehicles and trucks and have no new information indicating that there is a problem with this approac h. EPA considers the SAE CRP’s approach to evaluating risk of HF to be sufficiently protective.

g. Low

- to

- no repetition data points (with insufficient information provided regarding sample protocol, collection point, etc.) appear to have been used to make de finitive risk conclusions without considering statistical variability and the impact it could have on subsequent safety conclusions.

EPA Response : It is not clear from the comment what substitute, end

- use, or test the commenting agency is referring to. I n general, EPA’s screening analyses for flammability and toxicity risks in this rule are based upon measurements when available, or exposure modeling using a box model if measured data are not available (see p. 63 of the preamble). EPA also uses any modele d or empirical information provided by submitters of the substitutes under review or other available industry data, which in some cases has included measured data (e.g., measurements of HF concentrations during decomposition of HFO

- 1234yf from the SAE Coop erative Research Program mentioned on p. 175 of the preamble).12 3/17 Interagency Follow

- Up Comment: The comment applies to the previous discussion on combustion byproducts (specifically HF) as well as the two “extreme condition” tests mentioned towards th e bottom of page 174 of the NOPR.

Regarding the last part of the response “...(e.g., measurements of HF concentrations during decomposition of HFO

- 1234yf from the SAE Cooperative Research Program mentioned on p. 175 of the preamble) :

. ” Note that there app ears to be a typo in the estimated risk cited from the SAE CRP1234

- 4 report. From page 174 of updated NOPR,

“ Based on the updated analysis, the estimated overall risk of vehicle fire exposure attributed to use of R

- 1234yf is conservatively estimated at 3x 10 12 events per vehicle operating hour

. ” We believe the exponent is missing a minus sign and the estimate is intended to be “3x10

- 12 ”

EPA Response: Thank you for the correction. EPA will change this in the preamble.

h. There is a strong reliance upon UL listing requirements (especially as they relate to refrigerant charge limits) without providing the details of assumptions made by the UL in determining that such limits were safe. We cannot verify the accuracy of this

a pproach. Our own calculations identified very plausible scenarios where the proposed refrigerant charge limits could create atmospheres in excess of 10% of LEL under catastrophic release scenarios discussed in the notice of proposed rulemaking.

EPA Res ponse : EPA relies on the consensus

- based standards from UL as directed under the National Technology Transfer and Advancement Act of 1995 and OMB Circular A

119, Federal Participation in the Development and Use of Voluntary Consensus Standards and in Confo rmity Assessment Activities . The UL standards include safety provisions that are independent of the specific charge size. For example, the UL standards require testing of equipment to ensure the leaked amount of refrigerant will remain well below the LFL ( e.g., sections SB5.1 of UL 471 for commercial refrigerators and freezers, SA 5.1 of UL 563 for ice makers). In the leak test, the measured concentration of leaked refrigerant is prohibited from exceeding 75% of the LFL at all times during testing and is pr ohibited from exceeding 50% of the LFL for any period exceeding 5 minutes.

Information is not available on the assumptions used by UL’s consensus

- based standard

- setting committees in selecting the charge size limit of 150 g. We note, however, that this c harge size limit has been widely adopted in Europe for stand

- alone equipment in locations that the public can access and is also a requirement in many international standards (e.g., IEC standards).

EPA’s risk screening analyses contain specific assumptio ns about factors such as effective room size, ventilation rates, charge sizes, length of release of refrigerant and whether leaked refrigerant is assumed to be evenly dispersed in a room or is concentrated close to the floor. The results of these analyses are described in the preamble.13

6. The provision concerning the 2022 phase

- out of HFC

- 134a in centrifugal and positive displacement compressor chillers will adversely impact national security unless narrowed use limits are crafted for our mission

- critical ap plications in marine vessels. The commenting agency is working closely with industry partners that produce this mission

- critical hardware to identify and eventually qualify suitable lower

- GWP alternatives. However, the lower

- GWP alternatives currently be ing offered or proposed for use in commercial chillers either do not meet the commenting agency's military

- unique requirements or will require longer timeframes to test for military suitability, and then redesign, qualify, a nd procure new chillers for the agency’s shipbuilding programs.

EPA Response : EPA is proposing a narrowed use limit that would allow use of HFC

- 134a in centrifugal and positive displacement compressor chillers beyond January 1, 202 4
, for certain military applications, specifically marine vessels.

7. 3/18 Comment: The commenting agency recently identified a possible chiller issue with the 2025 date. The agency plans to use HFC 134a as a coolant on the Orion capsule while it is on the g round. A chiller will circulate the coolant until launch. If this type of use would be unacceptable with the regulatory language as written, we would appreciate it if EPA would consider including space vehicle applications in the chiller narrow use limit . The commenting agency appreciates EPA’s flexibility to consider unique NASA mission applications.

EPA Response: EPA will propose a narrowed use limit for R

- 134a and R

- 404A in new centrifugal chillers and positive displacement chillers for use in human

- rate d spacecraft.

8. 3/23 Comment: Will EPA add a reference in the New Cold Storage Warehouse section that discusses DOE regulatory efforts regarding Walk

- In Coolers and Walk

- In Freezers? The following language was paraphrased from DOE’s technical amendments final rule 80 FR 69837 (November 12, 2015) that was issued in response to litigation on DOE’ s final rule from June 3, 2014. The compliance timing of the reconsideration rule has not yet been publicly announced, but DOE indicated that the compliance date would likely be at the end of 2019.

DOE issued a final rulemaking on June 3, 2014 (79 FR 32049) that set nineteen energy conservation standards for walk

- in coolers and walk

- in freez ers with a compliance date of June 5, 2017 . Due to litigation regarding this rulemaking, DOE vacated six of those standards for refrigeration systems and is currently engaged in a negotiated rulemaking to address the standards as referenced in the agency’ s technical amendments final rulemaking 80 FR 69837 (November 12, 2015)

.
EPA Response : EPA is adding this language to the preamble in the section discussing the relationship between this rule and other federal rules:



### DOE issued a final rulemaking on Jun e 3, 2014 (79 FR 32049) that set nineteen energy conservation standards for walk

- in coolers and walk

- in freezers with a compliance date of June 5, 2017. Due to litigation regarding this rulemaking, DOE vacated six of those standards for refrigeration syste ms and is currently engaged in a negotiated rulemaking to address the standards as referenced in the agency’s technical amendments final rulemaking14



### 80 FR 69837 (November 12, 2015). Consistent with DOE’s rule, which defines walk

- in coolers and walk

- in freez ers as having a total chilled storage area of less than 3,000 square feet, EPA considers such equipment to fit within the retail food refrigeration end

- use, rather than the cold storage warehouse end

- use. Thus, we consider there to be no regulatory overlap between this proposed rule and the DOE energy conservation standards for walk

- in coolers and freezers.

9. 3/23 Comment : NASA requests that EPA add spacecraft applications as “acceptable subject to narrowed use limits” after January 1, 2025 for centrifugal chiller and positive displacement chiller end uses of HFC 134a and R

- 404A. We appreciate EPA’s flexibility to consider unique NASA mission

- critical applications. Below is the justification language provided by NASA concerning their Orion mission. Will EPA include and request comment as they may revise their request prior to issuing the final rule?

NASA has recently identified an additional issue related to EPA’s proposed provisions limiting the use of coolants, including HFC 134a and R

- 404A, in chille rs. The agency anticipates being able to transition chillers to acceptable coolants for most uses. However, NASA plans to use HFC 134a and R

- 404A to provide cooling to human

- rated spacecraft during ground

- based assembly, integration and test operations, and launch. The cooling of sensitive human

- rated electrical equipment is critical to the spacecraft technical performance and crew safety. NASA programs use specialized ground coolant systems to provide heat transfer during certain ground operations. Th ese coolant circulation systems use HFC 134a and R

- 404A to meet the program’s stringent performance and material compatibility requirements. Alternate substances listed as acceptable under the SNAP program may not provide appropriate heat transfer, materi al compatibility, stability in the test environment, and other critical properties. Considering that identification, testing, and implementation of materials to be used in human

rated spaceflight programs routinely take several years due to the challengin g operational environment, lengthy qualification process associated with human rating, and the federal budgetary cycle, NASA does not expect to be able to deploy substitute coolants in EPA’s proposed timeframe.

EPA Response: EPA will propose a narrowed use limit for R

- 134a and R

- 404A in new centrifugal chillers and positive displacement chillers for use in human

- rate d spacecraft.