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. 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 freezers 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 June 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 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). Consistent with DOE’s rule, which 

defines walk-in coolers and walk-in freezers 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. 

3/24 Interagency Comment: 

Commenting agency notes that the definition of a walk-in cooler and freezer is set by statute at 

42 U.S.C. 6311(20):

(A) In general. —

The terms "walk-in cooler" and "walk-in freezer" mean an enclosed storage space refrigerated 

to temperatures, respectively, above, and at or below 32 degrees Fahrenheit that can be walked 

into, and has a total chilled storage area of less than 3,000 square feet.

(B) Exclusion.—
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The terms "walk-in cooler" and "walk-in freezer" do not include products designed and 

marketed exclusively for medical, scientific, or research purposes.

In the commenting agency’s view, except in certain limited cases – such as with food 

preparation rooms or facilities involving blast chillers/freezers – any equipment that meets this 

definition would be considered by the commenting agency as a walk-in. 

The commenting agency also notes that DOE’s regulations for walk-ins are equipment-based 

while EPA’s are end-use application-based. If a given refrigerant that EPA is proposing to 

address is designed for use in walk-in equipment with a total chilled storage area of less than 

3000 square feet as well as retail storage facilities with a total chilled storage area of 3,000 

square feet or more, that fact would seem to suggest that there is a potential risk of regulatory 

overlap between this proposed SNAP action and DOE’s already-established regulatory 

framework for walk-ins.

3/25 EPA Response: EPA will make the following edits to the preamble text.

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 freezers 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). For purposes of the DOE regulations, the Energy Conservation Act 42

U.S.C. 6311(20) defines walk-in coolers and walk-in freezers as having a total chilled storage 

area of less than 3,000 square feet. EPA considers the vast majority of such equipment to fit 

within the retail food refrigeration end-use, rather than the cold storage warehouse end-use. As 

described in the July 20, 2015 SNAP final rule, walk-in coolers and walk-in freezers as 

pertaining to DOE regulations could fall in the SNAP retail food refrigeration end-use category 

“supermarket system” (i.e., where refrigerant from a multi-compressor rack was supplied to the 

evaporator(s) in the walk-in enclosed storage space), “remote condensing unit” (where a 

dedicated one- or two-compressor system installed in the field supplied the refrigerant to the 

walk-in enclosed storage space) or “stand-alone equipment” (where the enclosed storage space 

is manufactured and delivered with all components including the refrigerant). Thus, we 

consider there to be no regulatory overlap between the vast majority of equipment to provide 

cooling to cold storage warehouses, which is addressed by this proposed rule and the DOE 

energy conservation standards for walk-in coolers and freezers. One exception might be where 

a refrigeration system (that does not otherwise fit into the SNAP end-use categories of 

supermarket system or remote condensing units) supplied refrigerant to an enclosed storage 

space with an area less than 3,000 square foot. This enclosed storage space would be required 

to meet both this proposed rule and the DOE requirements. On the other hand, if this 

refrigeration system supplied refrigerant to two enclosed storage spaces, one with an area 

greater than 3,000 square foot and one with an area less than that amount, both spaces would 

be covered by this proposed rule as cold storage warehouses while only the smaller room is 

covered by the DOE requirements.
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2. 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 chillers. 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. These 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, material compatibility, stability in the test environment, and other critical properties. 

Considering that identification, testing, and implementation of materials to be used in humanrated spaceflight programs routinely take several years due to the challenging 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 spacecraft.

3/24 Interagency Comment: Currently, the EPA language says “acceptable, subject to 

narrowed use limits, for human-rated spacecraft”

To address the specific equipment that provides for safety, the commenting agency requests 

that EPA add “and related support equipment” in the narrow use exemption to read 

“...acceptable, subject to narrowed use limits, for human-rated spacecraft and related support 

equipment”

This specific language is to ensure that the targeted narrowed use exemption covers the launch 

and spacecraft equipment functions discussed in our justification that protect the safety of our 

human spaceflight crews and the spacecraft.

3/25 EPA Response: EPA will add “and related support equipment” to the relevant discussion 

in the preamble and the regulatory text. 

3. 2/25 Comment: 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 into the analysis. From the 
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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. 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 exacerbate 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 

the 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 limited 

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. Upon 

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 minimum room volume below)”. 

Regarding “...or at least 15 m3 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) Discussion:

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)

Assumption: 

Commented [A1]: 3/24 Interagency Comment: The commenter 

provided suggested requests for comment in the preamble. The 

requests for comment provide sufficient clarity such that the public can 

determine and subsequently evaluate exactly what assumptions EPA 

had made in conducting their risk analysis.

Commented [EPA2R1]: 3/25 EPA response: As discussed, 

EPA will take comment in the preamble on the risk screens and their 

assumptions. 

Commented [A3]: 3/24 Interagency Comment: Given recent 

discussions and shared calculations between EPA and the commenting 

agency on this issue, the commenting agency is concerned that the 

removal of a minimum floor space use condition would only serve to 

exacerbate the hazard potential. 

Commented [EPA4R3]: 3/25 EPA response: As discussed, 

EPA will remove this requirement from the proposed use 

condition and will seek comment in the preamble on the risk 

screens and their assumptions.
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(1) Room height in EPA/NOPR proposed room volume is 2.44m (8’) [Note: A taller room 

height would be an even worse scenario)

Calculations: 

(1) Floor area = V/h = 22 m3 / 2.44m = 9m2

(2) Vol of propane-contaminated atmosphere = 9m2 x 0.4m = 3.6 m3

(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/m3

(5) 39583 mg/m3 / ((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 of 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 have 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 potential 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. Commented [A5]: 3/24 Interagency Comment: Will EPA go out 

for comment with the specific question: “Is the EPA’s use of 100% of 

the LFL an appropriate criterion for determination of an acceptably 

safe environment within the EPA risk screens?”

Commented [EPA6R5]: 3/25 EPA response: As discussed, 

EPA will post the risk screen to the docket and take comment in the 

preamble on the risk screens and their assumptions.