[6450-01-P]

DEPARTMENT OF ENERGY 

10 CFR Part 431 

[Docket No. EERE-2008-BT-TP-0014] 

RIN: 1904-AB85 

Energy Conservation Program: Test Procedures for Walk-In Coolers and Walk-In 

Freezers 

AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. 

ACTION: Notice of Proposed Rulemaking and Public Meeting. 

SUMMARY: Pursuant to the Energy Policy and Conservation Act, as amended, the U.S. 

Department of Energy (DOE) is proposing test procedures for measuring the energy 

consumption of walk-in coolers and walk-in freezers (collectively “walk-in equipment” or 

"walk-in(s)"), definitions to delineate the products covered by the test procedures, and provisions 

(including a sampling plan) for manufacturers to implement the test procedures. The notice also 

addresses enforcement issues as they relate to walk-in equipment. Concurrently, DOE is 

undertaking an energy conservation standards rulemaking for this equipment. Any data gathered 

through the use of the test procedure adopted by DOE will be used in evaluating any potential 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
standards for this equipment. Once these standards are promulgated, the adopted test procedures 

will be used to determine equipment efficiency and compliance with the standards. 

DATES: DOE will hold a public meeting in Washington, DC on Thursday, February 11, 2010, 

beginning at 9:00 a.m. DOE must receive requests to speak at the meeting before 4:00 p.m., 

Thursday, January 28, 2010. DOE must receive a signed original and an electronic copy of 

statements to be given at the public meeting before 4:00 p.m., Thursday, January 28, 2010. 

DOE will accept comments, data, and information regarding this notice of proposed 

rulemaking (NOPR) before or after the public meeting, but no later than [Insert date 75 days 

after date of publication in the Federal Register]. See section V, “Public Participation,” of this 

NOPR for details. 

ADDRESSES: The public meeting will be held at the U.S. Department of Energy, Forrestal 

Building, Room 8E-089, 1000 Independence Avenue, SW., Washington, DC 20585-0121. To 

attend the public meeting, please notify Ms. Brenda Edwards at (202) 586-2945. Please note that 

foreign nationals participating in the public meeting are subject to advance security screening 

procedures, requiring a 30-day advance notice. If you are a foreign national and wish to 

participate in the public meeting, please inform DOE as soon as possible by contacting Ms. 

Brenda Edwards at (202) 586-2945 so that the necessary procedures can be completed. 

Any comments submitted must identify the NOPR for Test Procedures for Walk-in 

Coolers and Freezers, and provide docket number EERE-2008-BT-TP-0014 and/or Regulation 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Identifier Number (RIN) 1904-AB85. Comments may be submitted using any of the following 

methods: 

1. Federal eRulemaking Portal: www.regulations.gov. Follow the instructions for 

submitting comments. 

2. E-mail: WICF-2008-TP-0014@hq.doe.gov. Include the docket number EERE-2008-BTTP-0014 and/or RIN 1904-AB85 in the subject line of the message. 

3. Postal Mail: Ms. Brenda Edwards, U.S. Department of Energy, Building Technologies 

Program, Mailstop EE-2J, 1000 Independence Avenue, SW., Washington, DC, 20585-

0121. Please submit one signed original paper copy. 

4. Hand Delivery/Courier: Ms. Brenda Edwards, U.S. Department of Energy, Building 

Technologies Program, 950 L’Enfant Plaza, SW., 6th Floor, Washington, DC 20024. 

Please submit one signed original paper copy. 

For detailed instructions on submitting comments and additional information on the 

rulemaking process, see section V, “Public Participation,” of this document. 

Docket: For access to the docket to read background documents or comments received, 

visit the U.S. Department of Energy, Resource Room of the Building Technologies Program, 950 

L’Enfant Plaza, SW., 6th Floor, Washington, DC 20024, (202) 586-2945, between 9 a.m. and 4 

p.m. Monday through Friday, except Federal holidays. Please call Ms. Brenda Edwards at the 

above telephone number for additional information regarding visiting the Resource Room. 

FOR FURTHER INFORMATION CONTACT: Mr. Charles Llenza, U.S. Department of 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Energy, Building Technologies Program, EE–2J, 1000 Independence Avenue, SW., Washington, 

DC 20585–0121, (202) 586–2192, Charles.Llenza@ee.doe.gov or Mr. Michael Kido, Esq., U.S. 

Department of Energy, Office of General Counsel, GC–72, 1000 Independence Avenue, SW., 

Washington, DC 20585– 0121, (202) 586–8145, Michael.Kido@hq.doe.gov.

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Authority and Background 

II. Summary of the Proposal 

III. Discussion 

A.Overall Approach 

1. Basic Model 

2. Approach Option 1: Test the Unit as a Whole 

3. Approach Option 2: Allow Manufacturers to Use Alternative Energy 

Determination Methods (AEDMs) 

4. Proposed Option and Recommendation: Separate Envelope and Refrigeration Tests 

B.Envelope 

1. Overview of the Test Procedure 

2. Test Methods 

a. Insulation 

b. Air Infiltration 

c. Steady-State Infiltration Test 

3. Calculations 

a. Energy Efficiency Ratio 

b. Heat Gain through the Envelope due to Conduction 

c. Heat Gain Due to Infiltration 

d. Envelope Component Electrical Loads 

e. Normalization 

f. Daily Energy Consumption Coefficients 

C.Refrigeration System 

1. Overview of the Test Procedure 

2. Test Conditions 

3. Test Methods 

4. Measurements and Calculations 

D.Compliance, Certification, and Enforcement 

1. Provisions for Energy Conservation Standards Developed by the Department of 

Energy 

2. Provisions for Existing Design Standards Prescribed by Congress 

IV. Regulatory Review 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
A.Review Under Executive Order 12866 

B.Review Under the National Environmental Policy Act 

C.Review Under the Regulatory Flexibility Act 

D.Review Under the Paperwork Reduction Act 

E.Review Under the Unfunded Mandates Reform Act of 1995 

F.Review Under the Treasury and General Government Appropriations Act, 1999 

G.Review Under Executive Order 13132 

H.Review Under Executive Order 12988 

I.Review Under the Treasury and General Government Appropriations Act, 2001 

J.Review Under Executive Order 13211 

K.Review Under Executive Order 12630 

L.Review Under Section 32 of the Federal Energy Administration (FEA) Act of 1974 

V. Public Participation 

A.Attendance at Public Meeting 

B.Procedure for Submitting Requests to Speak 

C.Conduct of Public Meeting 

D.Submission of Comments 

E.Issues on Which DOE Seeks Comment 

1. Test Procedure Improvements 

2. Basic Model 

3. Separate Envelope and Refrigeration Tests 

4. Definition of Envelope 

5. Effect of Impermeable Skins on Long-Term R-Value 

6. Measuring Long-Term R-Value Using American Society for Testing and Materials 

(ASTM) C1303-08 

7. Infiltration 

8. Nominal Coefficient of Performance of Refrigeration 

9. Measuring the U-Value of glass 

10. Floor R-Value 

11. Electrical Duty Cycle 

12. Normalization Factor 

13. Daily Energy Consumption Coefficients 

14. Definition of Refrigeration System 

15. Measurements and Calculations of Energy Use of Refrigeration Systems 

16. Impacts on Small Businesses 

VI. Approval of the Office of the Secretary 

I. Authority and Background 

Title III of the Energy Policy and Conservation Act of 1975, as amended (EPCA or the 

Act) sets forth a variety of provisions designed to improve energy efficiency. Part B of Title III 

(42 U.S.C. 6291–6309) provides for the Energy Conservation Program for Consumer Products 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Other Than Automobiles. The National Energy Conservation Policy Act (NECPA), Pub. L. 95-

619, amended EPCA to add Part C of Title III, which established an energy conservation 

program for certain industrial equipment. (42 U.S.C. 6311-6317) (These parts were subsequently 

redesignated as Parts A and A-1, respectively, for editorial reasons.) Section 312 of the Energy 

Independence and Security Act of 2007 (EISA 2007) further amended EPCA by adding certain 

equipment to this energy conservation program, including walk-in coolers and walk-in freezers 

(collectively “walk-in equipment” or “walk-ins”), the subject of this rulemaking. (42 U.S.C 

6311(1), (2), 6313(f) and 6314(a)(9)) 

EPCA defines walk-in equipment as follows: 

(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.— 

The terms “walk-in cooler” and “walk-in freezer” do not include products 

designed and marketed exclusively for medical, scientific, or research purposes. 

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

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Walk-ins covered by this rulemaking may be located indoors or outdoors. They may be 

used exclusively for storage, but they may also have transparent doors or panels for the purpose 

of displaying stored items. Examples of items that may be stored in walk-ins include, but are not 

limited to, food, beverages, and flowers. DOE notes that any equipment that meets the above 

definition is potentially subject to regulation. 

Under the Act, the overall program consists essentially of the following parts: testing, 

labeling, and Federal energy conservation standards. The testing requirements for covered 

equipment consist of test procedures, prescribed under EPCA. These test procedures are used in 

several different ways: (1) any data from the use of these procedures are used as a basis in 

developing standards for covered products or equipment; (2) the test procedure is used when 

determining equipment compliance with those standards; and (3) manufacturers of covered 

equipment must use the procedure to establish that their equipment complies with energy 

conservation standards promulgated pursuant to EPCA and when making representations about 

equipment efficiency. 

Section 343 of EPCA (42 U.S.C. 6314) sets forth generally applicable criteria and 

procedures for DOE’s adoption and amendment of such test procedures. That provision requires 

that the test procedures promulgated by DOE be reasonably designed to produce test results 

which reflect energy efficiency, energy use, and estimated operating costs of the covered 

equipment during a representative average use cycle. It also requires that the test procedure not 

be unduly burdensome to conduct. See 42 U.S.C. 6314(a)(2). As part of the process for 

promulgating a test procedure, DOE must publish the procedure that it plans to propose and offer 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
the public an opportunity to present oral and written comments on them. Consistent with 

Executive Order 12889 and EPCA (see 42 U.S.C. 6314(b)), DOE provides a minimum comment 

period of 75 days on a proposed test procedure. As to the test procedures for walk-in equipment, 

EPCA prescribes the following requirements: 

(A) In general.— 

For the purpose of test procedures for walk-in coolers and walk-in freezers: 

(i) The R value shall be the 1/K factor multiplied by the thickness of the panel. 

(ii) The K factor shall be based on ASTM [American Society for Testing and 

Materials] test procedure C518–2004. 

(iii) For calculating the R value for freezers, the K factor of the foam at 20°F 

(average foam temperature) shall be used. 

(iv) For calculating the R value for coolers, the K factor of the foam at 55°F 

(average foam temperature) shall be used. 

(B) Test Procedure.— 

(i) In general.—Not later than January 1, 2010, the Secretary shall establish a 

test procedure to measure the energy-use of walk-in coolers and walk-in 

freezers. 

(ii) Computer modeling.—The test procedure may be based on computer 

modeling, if the computer model or models have been verified using the results 

of laboratory tests on a significant sample of walk-in coolers and walk-in 

freezers. (42 U.S.C. 6314(a)(9)) 

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On February 4, 2009, DOE held a public meeting on the framework document it issued 

concerning the DOE rulemaking to evaluate walk-in equipment for energy conservation 

standards. See 74 FR 411 (Jan. 6, 2009) and 74 FR 1992 (Jan. 14, 2009). Both the framework 

document and meeting discussed the possible test procedures for this equipment that DOE was 

considering at that time, and gave interested parties an opportunity to submit comments. Today's 

notice addresses those comments and proposes test procedures for walk-in equipment. 

II. Summary of the Proposal 

In today’s notice, DOE proposes to adopt new test procedures for determining the energy 

use of walk-in cooler and walk-in freezer equipment to address the statutory requirement to 

establish a test procedure by January 1, 2010. (42 U.S.C. 6314(a)(9)(B)) Concurrently, DOE is 

undertaking an energy conservation standards rulemaking for walk-in equipment to address the 

statutory requirement to establish performance standards no later than January 1, 2012. (42 

U.S.C. 6313(f)(4)(A)) DOE will use any data resulting from use of the test procedure that DOE 

adopts to evaluate potential performance standards for this equipment. Furthermore, once 

performance standards are issued, manufacturers would be required to use the test procedures to 

determine compliance with such standards and for any representations regarding the energy use 

of walk-in equipment they produce. This test procedure, once adopted, would serve as the means 

for ascertaining compliance with the appropriate standards in an enforcement action. 

For the reasons described below, DOE proposes to adopt a test procedure that contains 

two separate test methods. This approach is necessary because there are typically two 

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manufacturers of walk-in equipment: one who manufactures the envelope (i.e., the insulated box 

in which the refrigerated or frozen items are stored) and one who manufactures the refrigeration 

system (i.e., the mechanism that provides the means by which to feed chilled air into the 

envelope). One method determines the energy consumption of the refrigeration system of the 

walk-in cooler or freezer. The other method determines the energy consumption of the envelope, 

which is the sum of the energy use associated with heat transmission through the envelope in the 

form of conduction through the walls and air infiltration through openings, and the power 

consumed by electrical components that are part of the envelope. Each of the two components, 

the refrigeration system and the envelope, is considered separately and the energy consumption 

of each component is calculated using the applicable test procedure. DOE believes that the 

approach is consistent with the requirements in EPCA because the results of the two tests will 

represent, in the aggregate, the total energy consumption of walk-in coolers and freezers. 

Using this approach, DOE believes that the proposed test procedures will adequately 

measure the energy consumption of walk-in equipment by capturing the energy consumption of 

both components. However, DOE requests comment from stakeholders on improvements or 

changes to the proposed test procedures and will consider modifications that improve the 

accuracy, appropriateness for the equipment being tested, repeatability of test results for the 

same or similar units, comparability of results for different types of units, burden on 

manufacturers, precision of language, or other elements of the procedures. In submitting 

comments, interested parties should state the nature of the recommended modification and 

explain how it would improve upon the test procedure proposed in this NOPR. Commenters 

should also submit data, if any, to support their positions. 

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DOE’s adoption of the proposed test procedures, which would be applicable to all walkin equipment, would not necessarily mean that DOE would adopt a single energy conservation 

standard or set of labeling requirements for all walk-in equipment. In the separate rulemaking 

proceeding concerning energy conservation standards for walk-in equipment, DOE may divide 

such equipment into classes and may conclude that standards are not warranted for some classes 

of equipment that are within the scope of today’s test procedure. Furthermore, DOE may create a 

separate standard for each class of equipment that includes a utility- or performance-related 

feature that another equipment class lacks, and that affects energy consumption. 

DOE also notes that the National Technology Transfer and Advancement Act of 1995 

(Pub. L. 104-113) directs Federal agencies to use voluntary consensus standards in lieu of 

Government standards whenever possible. Consequently, as described in the following 

paragraphs, DOE attempted to incorporate by reference in its test procedures generally accepted 

rules or recognized industry standards such as those issued by the Air-Conditioning, Heating and 

Refrigeration Institute (AHRI), the American Society of Heating, Refrigerating, and Air 

Conditioning Engineers (ASHRAE), the American National Standards Institute (ANSI), and/or 

ASTM International (ASTM), that provide either specific aspect(s) of the test procedure, or the 

complete test procedure, for the specified equipment. 

III. Discussion

In the following section, DOE describes the overall approach it proposes to follow with 

respect to the adoption of a test procedure for walk-ins. This approach results from the 

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characteristics of walk-in equipment and is based in part on the basic model definition that DOE 

currently uses to help establish testing requirements for manufacturers to follow. The following 

section also addresses issues raised by commenters, which included: manufacturers (Craig 

Industries (Craig), Manitowoc, Nor-Lake); trade associations (AHRI); utility companies 

(Southern California Edison (SCE), Sacramento Municipal Utility District (SMUD), San Diego 

Gas and Electric (SDG&E); and advocacy groups (Appliance Standards Awareness Project 

(ASAP), American Council for an Energy-Efficient Economy (ACEEE), Natural Resources 

Defense Council (NRDC), Northwest Energy Efficiency Alliance (NEEA)). 

A. Overall Approach 

DOE developed today’s proposed test procedure to set forth the testing requirements for 

walk-in equipment. In the framework document, DOE considered two overall approaches 

manufacturers could take to determine the energy consumption of walk-in coolers and freezers. 

First, DOE considered using a modified version of the Air-Conditioning and Refrigeration 

Institute (ARI) Standard 1200-2006, “Performance Rating of Commercial Refrigerated Display 

Merchandisers and Storage Cabinets” (ARI 1200-2006), which uses the test method described in 

the American National Standards Institute/American Society of Heating, Refrigerating, and Air 

Conditioning Engineers (ANSI/ASHRAE) Standard 72-2005, “Method of Testing Commercial 

Refrigerators and Freezers” (ANSI/ASHRAE 72-2005). Second, DOE considered allowing 

manufacturers to determine the efficiency of some of their products using alternative efficiency 

determination methods (AEDMs). (An AEDM is a predictive mathematical model, developed 

from engineering analyses of design data and substantiated by actual test data, which represents 

the energy consumption characteristics of one or more basic models.) 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE received comments on these proposed approaches, many of which were opposed to 

both approaches. The comments DOE received, and DOE’s responses, are discussed in more 

detail below. After considering these comments and reviewing the matter further, DOE is 

proposing separate test procedures for the envelope (insulated box) and the refrigeration system. 

DOE discusses the details of its proposals and addresses manufacturer comments in the 

following subsections. 

1. Basic Model 

Under EPCA, which prohibits the distribution in commerce of covered equipment that do 

not comply with the applicable standard, each model of covered equipment is potentially subject 

to energy efficiency testing consistent with the relevant requirements for that equipment. 

However, walk-in manufacturers typically make numerous envelope models and, even within a 

single model, the units are often customized in multiple ways. To reduce this potential burden, 

DOE proposes following the approach it has used for other equipment by allowing 

manufacturers to group equipment or models with essentially identical energy consumption 

characteristics into a single family of models, called a basic model. This concept has been 

established both for residential appliances and commercial and industrial equipment covered 

under EPCA. (See Title 10 of the Code of Federal Regulations (10 CFR) 430.2, which covers 26 

products, and 10 CFR 431.12, 431.62, 431.132, 431.172, 431.192, 431.202, 431.222, 431.262, 

and 431.292, which cover various equipment.) 

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Walk-in refrigeration systems are often manufactured according to the same basic 

blueprint design, and any particular model could incorporate modifications that do not 

significantly affect the energy efficiency of the system. For example, manufacturers often sell 

systems that are designed to operate at different voltages. This allows them to market to 

customers with different electrical capabilities. The operating voltage affects the energy 

efficiency of the system, but very minimally. If manufacturers were required to test the 

efficiency of each model with a different feature, the testing burden would be significant, but 

yield effectively redundant results. Therefore, DOE provides for testing of a basic model of 

refrigeration systems that may not be identical, but would not have any electrical, physical, or 

functional characteristics that significantly affect energy consumption. Features that may affect 

the energy consumption of walk-in cooler and freezer refrigeration systems include compressor 

size, fan motor type, and heat exchanger coil dimensions. 

Walk-in envelopes are often manufactured according to the same basic design, but the 

equipment is so highly customized that each walk-in a manufacturer builds may be unique, and 

potentially subject to testing as a separate basic model. For instance, changing the size of the 

envelope would affect the energy consumption obtained by the test procedure, even if the 

construction methods and materials were the same. To address this possibility, DOE proposes (1) 

grouping walk-in envelopes with essentially identical construction methods, materials, and 

components into a single basic model, and (2) adopting a calculation methodology for 

determining the energy consumption of units within the basic model. This methodology would 

require a manufacturer to test one unit of the basic model and then calculate daily energy 

consumption coefficients (DECCs) for that basic model according to the test procedure. The 

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manufacturer could then apply those DECCs to other units within a basic model even if those 

units were not identical, to obtain the energy consumption of those units. Although units within a 

basic model need not share identical dimensions, finishes, and non-energy-related features (e.g. 

shelving or door kick plates), they must have been manufactured using substantially the same 

construction methods, materials, and components. A few examples of factors that would 

necessitate a different basic model include changing the type of insulating foam, the method of 

locking together the panels of the walk-in envelope, or the electrical characteristics of the 

lighting. Examples of factors that may not constitute a different basic model include the type of 

exterior metal finish, the dimensions of the envelope, and the number of doors of the same type. 

The exterior metal finish would not have a substantial impact on the efficiency of the envelope. 

Dimensions and number of doors, on the other hand, would be accounted for in the energy 

consumption calculation using the DECCs from the unit of the basic model that was tested. (See 

section III.B.3.f for further discussion of DECCs.) 

All of the equipment included in a basic model must be within the same equipment class. 

Components of similar design may be substituted in a basic model without requiring additional 

testing if the represented energy consumption measurements continue to satisfy the provisions 

for sampling and testing. Only representative samples within each basic model would be tested. 

For walk-ins, DOE is considering adopting the following definition of “basic model:” 

“Basic Model means all units of a given type of walk-in equipment manufactured by a single 

manufacturer, and— (1) With respect to envelopes, which do not have any differing construction 

methods, materials, components, or other characteristics that significantly affect the energy 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
consumption characteristics. (2) With respect to refrigeration systems, which have the same 

primary energy source and which do not have any differing electrical, physical, or functional 

characteristics that significantly affect energy consumption.” DOE requests comment on its 

proposed basic model approach. 

2. Approach Option 1: Test the Unit as a Whole 

In the framework document, DOE considered developing a test procedure for walk-ins by 

adapting an existing test procedure for commercial refrigeration equipment, such as ARI 1200-

2006. This approach would require an entire walk-in cooler or freezer to be physically tested 

within a controlled test chamber in order to evaluate its energy consumption over a period of 

time. During the standards framework public meeting, DOE requested comments on the 

feasibility of this approach. Interested parties responded with significant reservations about using 

a modified version of the ARI 1200-2006 test procedure, citing crucial differences between 

walk-ins and commercial refrigeration equipment. 

In particular, interested parties noted that walk-ins are physically different from 

commercial refrigerators in ways that make a full-system test burdensome or impractical. 

Manitowoc stated that for very large walk-ins, around the 3,000-square-foot limit in the EPCA 

definition, manufacturers might not have a large enough test facility to make the measurements 

necessary for the ARI 1200-2006 test procedure in a controlled environment. (Manitowoc, Public 

Meeting Transcript, No. 15 at p. 59) (In this and subsequent citations, “Public Meeting 

Transcript” refers to the transcript of the February 4, 2009, public meeting on standards for walkin coolers and freezers. “No. 15” refers to the document number of the transcript in the Docket 

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for the DOE rulemaking on standards for walk-in coolers and freezers, Docket No. EERE-2008-

BT-TP-0014; and the page references refer to the place in the transcript where the statement 

preceding appears.) Kason Industries also stated that it would be practically impossible to have a 

large enough controlled climate enclosure to test medium to large walk-ins, and added that if a 

walk-in were a free-standing structure, testing it as a whole building would not be practical. 

(Kason, No. 16 at pp. 1, 4) (In this and subsequent citations, the document number refers to the 

number of the comment in the Docket for the DOE rulemaking on standards for walk-in coolers 

and freezers, Docket No. EERE-2008-BT-TP-0014; and the page references refer to the place in 

the document where the statement preceding appears.) The Air-Conditioning, Heating, and 

Refrigeration Institute (AHRI) stated that the proposed test procedures were not practical 

because it would be costly to physically test walk-ins. (AHRI, No. 33 at p. 2) 

Commenters also noted that the market for walk-in coolers and freezers is structured 

differently from the market for commercial refrigeration equipment, making a direct comparison 

between these types of equipment difficult. Manitowoc stated that the envelope of a particular 

unit of walk-in equipment may be manufactured by one company and the refrigeration system by 

another company. ARI 1200-2006 would require the two systems to be integrated before running 

the test, which would place the burden on the installer or someone beyond the manufacturer of 

the subsystems. (Manitowoc, Public Meeting Transcript, No. 15 at p. 59) AHRI agreed that the 

ARI 1200-2006 standard might not be the right approach and that DOE would need to separate 

the mechanical system from the envelope. (AHRI, Public Meeting Transcript, No. 15 at p. 62) 

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In addition to these concerns, commenters identified a deficiency in the ARI 1200-2006 

test procedure. SCE stated that the majority of potential energy savings can be achieved using 

floating head pressure and variable-speed evaporator fans, both of which have varying effects 

depending on the time of day and the regional climate because the savings associated with each 

feature can depend on the ambient temperature and usage patterns of the walk-in over the course 

of a day. Because ARI 1200-2006 is a steady-state test, it would not capture the energy savings 

from either option. (SCE, Public Meeting Transcript, No. 15 at p. 63) AHRI agreed that the test 

procedure should capture savings from a control strategy or variable-speed components, both of 

which could optimize the operation of the walk-in for a variety of ambient conditions and usage 

patterns. An example of optimization would be allowing elements of the refrigeration system to 

turn off or reduce their operation at night when the walk-in is not being accessed. (AHRI, No. 33 

at p. 2) 

After considering these comments, DOE believes that an adapted version of ARI 1200-

2006 would be inadequate to use as the test procedure for walk-in equipment. ARI 1200-2006 

contains too many limitations and practical difficulties that would make it very difficult to 

effectively implement as a workable test procedure for walk-in. Therefore, DOE is no longer 

considering this approach. 

3. Approach Option 2: Allow Manufacturers to Use Alternative Energy Determination 

Methods (AEDMs) 

DOE's framework document also presented an alternative that would permit the use of an 

AEDM when determining walk-in energy consumption to help relieve the testing burden on 

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manufacturers. An AEDM is a predictive mathematical model, developed from engineering 

analyses of design data and substantiated by actual test data which represents the energy 

consumption characteristics of one or more basic models. After confirming the accuracy of an 

AEDM, the manufacturer would apply the AEDM to basic models to determine their energy 

consumption without conducting any physical testing. 

Applying this approach, the manufacturer would confirm the accuracy of the AEDM 

using the following method. First, the manufacturer would determine through actual testing the 

energy consumption of a certain number of its basic models that would be selected in accordance 

with criteria specified in the procedure. Second, the manufacturer would apply the AEDM to 

these same basic models. The AEDM would be considered sufficiently accurate only if: (1) the 

predicted total energy consumption of each of these basic models, calculated by applying the 

AEDM, is within a certain percentage of the total energy consumption determined from the 

testing of that basic model; and (2) the average of the predicted total energy consumption for the 

tested basic models, calculated by applying the AEDM, is within a certain percent of the average 

of the total energy consumption determined from testing these basic models. Under this 

approach, once the manufacturer verifies the accuracy of the AEDM, the manufacturer can use 

the AEDM to determine the energy consumption of other basic models without having to test 

those models. DOE requested comments on this approach during the framework public meeting, 

both in terms of how to implement the approach and whether such an approach was valid for 

walk-ins at all. DOE received several relevant comments, which are described and addressed 

below. 

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Given the unprecedented nature of using an AEDM to rate this type of equipment, DOE 

needed to determine both an appropriate sample size for verifying an AEDM and an acceptable 

minimum accuracy percentage for an AEDM. During the framework public meeting, DOE 

requested comments on these two values. AHRI could not provide feedback on how accurate the 

AEDM should be because DOE had not yet determined the test metric to apply. (AHRI, Public 

Meeting Transcript, No. 15 at p. 69) Manitowoc agreed that the test methodology needs to be 

established and experiments conducted to collect data that would be used to validate AEDMs. 

(Manitowoc, Public Meeting Transcript, No. 15 at p. 70) In a written comment, Kason Industries 

stated that an AEDM with a minimum accuracy of 66 percent would encompass a majority of the 

wide range of walk-in cooler and freezer applications. (Kason, No. 16 at p. 2) No commenter 

provided substantive data that DOE would use in its analysis to help support a particular sample 

size. Accordingly, DOE did not receive enough data from stakeholders that could help it 

determine an appropriate sample size or accuracy range to substantiate an AEDM. 

During the public meeting, DOE also requested comments on the possibility of allowing 

manufacturers to take this approach to rate their walk-ins. Kason stated that an AEDM procedure 

would be preferable to using a physical test because the majority of walk-ins are custom-made 

by size, ambient temperature, and refrigeration demands. Therefore, it would be very difficult to 

create a test procedure that encompasses the range of walk-in equipment. (Kason, No. 16 at p. 1) 

Kason suggested that, as an alternative to testing the system as a whole, an AEDM could be 

based on determining efficiencies and performance characteristics for the principal components 

of a walk-in considering three factors: insulation and air tightness of the external envelope and 

door, efficiency of the refrigeration system for steady-state storage load (similar to the efficiency 

20 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
rating system for HVAC), and performance of the refrigeration system for removal of process 

heat and equipment-generated heat. (Kason, No. 16 at p. 2) 

Other interested parties commented that allowing manufacturers to develop their own 

calculation methodology or software program as an AEDM could be problematic. Owens 

Corning questioned whether there could be a comparison among ratings published by 

manufacturers that developed different AEDMs. (Owens Corning, Public Meeting Transcript, 

No. 15 at p. 64) Craig stated that manufacturers who devise their own test procedures could write 

them in a way that benefits their own company. (Craig, Public Meeting Transcript, No. 15 at pp. 

68-69) SCE stated that allowing manufacturers to develop their own software as an AEDM could 

be unfair to manufacturers with fewer resources, because the software is expensive and timeconsuming to develop. Instead, SCE suggested that it would be better to have a transparent 

analysis method with the algorithms available to all participants and the data in a standardized 

format. (SCE, Public Meeting Transcript, No. 15 at p. 71) Craig replied that many manufacturers 

have sizing programs, which may be proprietary, to calculate the total load of the walk-in, 

accessories, and product load, and to size the refrigeration system properly for the energy 

requirements of the envelope. (Craig, Public Meeting Transcript, No. 15 at pp. 77-78 and No. 22 

at p. 4) However, Craig stressed that requiring manufacturers to follow the same model 

developed or approved by DOE, would be fair to different manufacturers and provide consistent 

information to end users. (Craig, Public Meeting Transcript, No. 15 at p. 94 and No. 22 at p. 5) 

ACEEE asserted that it would be difficult for DOE to work with many proprietary 

models, some of which might be difficult to verify. (ACEEE, Public Meeting Transcript, No. 15 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
at p. 94) NEEA also said that if an AEDM were used, the software should be equally available to 

all manufacturers and code officials for the purpose of determining compliance. (NEEA, No. 18 

at p. 3) Crown Tonka stated that a standard configuration and standard test should be developed 

to create a baseline for energy usage, with normalizing factors associated with configuration 

changes. (Crown Tonka, No. 23 at p. 1) Owens Corning reiterated that a single AEDM should be 

accepted to keep comparisons consistent. (Owens Corning, No. 31 at p. 2) 

DOE had previously understood that manufacturers would develop their own AEDMs 

and would verify their accuracy by testing a small number of walk-in models. However, as 

discussed above, most interested parties indicated that allowing manufacturers to develop their 

own rating calculations or software could be problematic, despite the fact that the calculations 

and software would need to be verified. Therefore, DOE does not propose to allow 

manufacturers to develop their own AEDMs. Instead, DOE developed its own calculation 

methodology for manufacturers to use in rating similar, but not identical, units of walk-in 

equipment. For further discussion on this methodology, see section III.B.3.f. 

4. Proposed Option and Recommendation: Separate Envelope and Refrigeration Tests 

Both methods described above were predicated on the assumption that an entire walk-in 

unit is manufactured by a single entity, which could either test the walk-in as a whole according 

to ARI Standard 1200-2006, or calculate the overall efficiency using an AEDM. In fact, as DOE 

learned, most walk-ins have two main manufacturers: one who manufactures the envelope and 

one who manufactures the refrigeration system that cools the interior of the envelope. (Other 

manufacturers may be involved in producing secondary components —such as fan assemblies or 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
lighting— that are then purchased by the main manufacturers and incorporated as part of the 

refrigeration system or envelope.) These two parts are manufactured separately, and are often 

assembled together in the field by a third-party contractor who may not have been responsible 

for the manufacture of either part, and who may not have testing or evaluation capabilities. 

Because of this situation, DOE developed, and is proposing, a different approach for testing 

walk-ins, as described below. 

Specifically, DOE proposes separate test procedures for the envelope and the 

refrigeration system. The envelope manufacturer would be responsible for testing the envelope 

according to the envelope test procedure, and the refrigeration system manufacturer would be 

responsible for testing the refrigeration system according to the refrigeration system test 

procedure. Such an approach would be more likely to generate usable data in support of 

standards for both the envelope and the refrigeration system during the development of any 

energy conservation standards for walk-in coolers and freezers. The two test procedures are 

described in sections III.B and III.C, respectively. 

There are several advantages to this approach. First, having separate test procedures 

would allow individual component manufacturers to test their components – the envelope and 

the refrigeration system. These component manufacturers would be more likely to have access to 

the resources, equipment, and personnel needed to conduct the tests. On the other hand, the 

“manufacturer” of an entire walk-in system (i.e., envelope and refrigeration system combined), 

could be a third party: a contractor who assembles the walk-in from the separate components 

and/or installs it in the field. This third-party assembler may even be the end-user or owner of the 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
equipment. If a walk-in is assembled in the field, testing of the entire assembled system may not 

be feasible due to lack of expertise and the need for additional testing equipment. 

Second, this approach would result in a significantly reduced testing burden while 

ensuring compliance with any standard DOE may develop. There are many more assemblers and 

installers of walk-ins than there are component manufacturers. Because EPCA requires 

manufacturers to demonstrate compliance with energy conservation standards, interpreting the 

term “manufacturer” to include assemblers and installers, who may be contractors or end-users, 

to demonstrate compliance with a standard would impose the compliance burden on entities who, 

more likely than not, may not have participated in the design and manufacture (and therefore 

energy efficiency) of the component parts. Furthermore, this approach would create substantial 

difficulties for DOE to enforce any standards it promulgates for walk-in equipment. While DOE 

considered the possibility that including assemblers and installers as parties involved in the 

manufacture of this equipment could encourage these parties to take steps to ensure that 

compliant equipment is installed, at this time, DOE believes that the testing burdens are best met 

by the envelope and refrigeration system manufacturers for the reasons discussed above. 

Accordingly, under today's proposal, only envelope and refrigeration system manufacturers 

would need to demonstrate compliance with any proposed standard through the use of the test 

procedure. (DOE notes that possible remedial action for failing to satisfy these requirements 

include civil penalties and injunctive relief to prevent the continued sale and distribution of 

noncompliant equipment.) (42 U.S.C. 6303-6304) 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE requests comment on this proposed approach and whether it is appropriate for walkins. 

B. Envelope 

As described earlier, the envelope consists of the insulated box in which the stored items 

reside. The following discussion describes in greater detail the test procedure DOE is proposing 

for the walk-in envelope. DOE also addresses issues raised by interested parties. 

This procedure contains the proposed methodology for evaluating the performance 

characteristics of the insulation as well as methods for testing thermal energy gains related to air 

infiltration caused by use (door openings) and imperfections in wall interfaces or door gasketing 

material. Heat gain due to internal electrical components is an additional consideration. 

The proposed procedure utilizes the data obtained to calculate a measure of energy use 

associated with the envelope. In other words, the test procedure calculates the effect of the 

envelope’s characteristics and components on the energy consumption of the walk-in as a whole. 

This includes the energy consumption of electrical components present in the envelope (such as 

lights) and variation in the energy consumption of the refrigeration system due to heat loads 

introduced as a function of envelope performance, such as conduction of heat through the walls 

of the envelope. The effect on the refrigeration system is determined by calculating the energy 

consumption of a theoretical, or nominal, refrigeration system, were it to be paired with the 

tested envelope. Using the same nominal refrigeration system characteristics allows for direct 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
comparison of the performance of walk-in envelopes across a range of sizes, product classes, and 

levels of feature implementation. 

The test procedure obtains a metric of energy use associated with the envelope of a walkin cooler or freezer, consistent with the statutory requirement (42 U.S.C. 6314(a)(9)(B)(i)). For 

purposes of this rulemaking, DOE interprets the term “energy use” to describe the sum of (a) the 

electrical energy consumption of envelope components and (b) the energy consumption of the 

walk-in refrigeration equipment that is contributed by the performance of the envelope. 

1. Overview of the Test Procedure 

In accordance with EPCA, DOE is developing test procedures to evaluate the energy use 

associated with the envelope of walk-in coolers and freezers. The walk-in envelope includes, but 

may not be limited to, walls, floor, ceiling, seals, windows, and/or doors comprised of single or 

composite materials designed to isolate the interior, refrigerated environment from the ambient, 

external environment. For the purposes of developing this test procedure and evaluating potential 

performance standards for walk-in equipment, DOE considers the envelope to also include 

lighting and other energy-consuming components of the walk-in that are not part of its 

refrigeration system (e.g., motors for automatic doors, anti-sweat heaters, etc.). DOE is 

considering the following definition for “envelope,” which would be inserted into 10 CFR part 

431: 

(1) the portion of a walk-in cooler or walk-in freezer that isolates the interior, refrigerated 

environment from the ambient, external environment; and 

26 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
(2) all energy-consuming components of the walk-in cooler or walk-in freezer that are not 

part of its refrigeration system. 

DOE requests comments on this proposed definition. 

DOE also evaluated several available industry test procedures to measure the energy 

performance of various components of the walk-in envelope, but was unable to find a test 

procedure that would evaluate the entire envelope system. Consequently, DOE developed its 

own methodology, including a prescriptive calculation procedure, which incorporates specific 

component tests and allows for an overall energy performance value of the envelope to be 

determined. The proposed test measurements and accompanying calculation procedures to 

ascertain the overall energy performance value are described in the following sections. 

2. Test Methods 

 As discussed above, DOE was unable to find a single, existing comprehensive test 

procedure for evaluating walk-in cooler and freezer envelopes. However, DOE identified and 

evaluated many recognized industry standards that could be applied to the testing of certain 

components and characteristics of walk-in envelopes. DOE incorporated an insulation test and an 

air infiltration test, with some modifications, into the proposed test procedure. The evaluation 

process, the results of the evaluation, and details of the proposed test methods are described in 

the following sections. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
a. Insulation 

Insulation comprises a significant component of walk-in units. EPCA specifies that 

ASTM C518-04, “Standard Test Method for Steady-State Thermal Transmission Properties by 

Means of the Heat Flow Meter Apparatus,” must be used, along with specific foam temperatures 

for freezer or cooler applications specified in EPCA, to determine the R-value of individual 

walk-in envelope insulation materials. (42 U.S.C. 6314(a)(9)(A)) Commenters identified two 

issues of significance for DOE to consider when developing a test procedure for insulation: aging 

and moisture absorption. DOE discusses these issues in the subsections that follow. 

i. Aging of Foam Insulation 

 EPCA requires that the test procedure for walk-ins use an R-value that shall be the 1/K 

factor multiplied by the thickness of the panel. (42 U.S.C. 6314(a)(9)(A)) The Act does not 

specify when the R-value should be calculated, a key issue interested parties raised at the 

framework public meeting. Specifying when the R-value should be calculated is a critical 

consideration because several sources indicate that the R-value of certain materials can change 

over time. 

Craig stated that R-values tend to deteriorate over time and that different materials 

exhibit unique rates of deterioration. (Craig, Public Meeting Transcript, No. 15 at p. 215 and No. 

8 at p. 1) Craig expressed concern that using an initial R-value (R-value as measured within two 

weeks of manufacture) to determine compliance would ignore deterioration that occurs in blown 

foams over time. Craig argued that underestimating the energy use of walk-ins would be the 

likely outcome of using initial R-value, that it would be misleading for end-users, and that it 

28 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
would be inconsistent with the goals of the EISA 2007 legislation and the rulemaking process. 

(Craig, Public Meeting Transcript, No.15 at p. 215) A comment submitted jointly by 

representatives of ASAP, ACEEE, and NRDC (hereafter referred to as the "Joint Comment") 

stated that the test procedures used should account for the potential degradation of panel 

insulation and door seals over time. (Joint Comment, No. 21 at p. 2) Craig also recommended 

that DOE develop an accelerated test procedure that represents lifetime energy use and can be 

completed within 6 months. (Craig, No. 8 at p. 1) 

In the context of foam insulation for walk-ins and the building industry, long-term 

thermal resistance (LTTR), described in greater detail below, refers to the impact of diffusion on 

the thermal resistance of insulation materials. In other words, the concentration of gaseous 

blowing agents contained in the foam, and which provide the foam with much of its insulating 

value, is reduced by both the diffusion of air into the foam and the secondary process of the 

blowing agent diffusing out of the foam. Because air has a significantly lower insulating value, 

the increased ratio of air to blowing agent reduces the foam insulation performance (this process 

is also known as “aging”). This diffusion process causes foam to lose insulating value, which is 

represented by its R-value. As a concept, LTTR represents the R-value of foam material over its 

lifetime by describing insulating performance changes due to diffusion over time. 

DOE investigated the issue of aging in foam insulation and found that it is widely 

accepted that the material properties of foam insulation made with gaseous blowing agents, other 

than air and including HFC-134a, HFC-245fa, HFC-365mfc, cyclopentanes, change over time. 

The amount of degradation can range from roughly 10-35 percent within 2 years of manufacture. 

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Because use of ASTM C518-04 reflects the properties of a material at the time it is tested, using 

ASTM C518-04 to measure the insulating performance of a foam material at the time of 

manufacture would yield a result that differs from that produced by the same test conducted at 

some later point in time. Additionally, research has found that the vast majority of diffusion into 

and out of foam materials manufactured with blowing agents other than air occurs within the first 

5 years of manufacture. Because the rate of diffusion follows an exponential curve, the majority 

occurs within the first year, after which the diffusion curve changes very little as it 

asymptotically approaches the equilibrium point. 

DOE found that various methods of “conditioning” foam prior to measuring its insulating 

ability with American Society for Testing and Materials (ASTM) C518 have been developed in 

order to test aged insulating value, or LTTR. These standards are contained in five foam material 

specifications: 

(1) ASTM C578-09, “Standard Specification for Rigid, Cellular Polystyrene Thermal 

Insulation;” 

(2) ASTM C591-08a, “Standard Specification for Unfaced Preformed Rigid Cellular 

Polyisocyanurate Thermal Insulation;” 

(3) ASTM C1029-08, “Standard Specification for Spray-Applied Rigid Cellular 

Polyurethane Thermal Insulation;” 

(4) ASTM C1126-04, “Standard Specification for Faced or Unfaced Rigid Cellular 

Phenolic Thermal Insulation;” and 

30 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
(5) ASTM C1289-08, “Standard Specification for Faced Rigid Cellular Polyisocyanurate 

Thermal Insulation Board.” 

DOE found that since their development in the 1980s, the most widely accepted 

conditioning methods are the 180-day conditioning at 73 °F or a 90-day conditioning at 140 °F. 

The goal of the 90-day conditioning method was to achieve the same aging result as the 180-day 

method in a shorter period of time. 180-day conditioning is used by ASTM C591-08a and ASTM 

C578-09 and the 90-day condition is typically used for ASTM C1089-08 and ASTM C1126-04. 

By accelerating the conditioning, the 90-day test sought to reduce the time and cost burdens for 

manufacturers. Although elevating the temperature of foams did achieve a faster rate of aging, 

subsequent research found that the results were not reliable indicators of actual aging because the 

relationship between the diffusion coefficient (a proportionality constant that describes the force 

or rate of diffusion for a given substance) and temperature are different for each gas. (Therese 

Stovall, “Measuring the Impact of Experimental Parameters upon the Estimated Thermal 

Conductivity of Closed-Cell Foam Insulation Subjected to an Accelerated Aging Protocol: TwoYear Results,” p. 1) 

DOE found that efforts to develop an accelerated aging method that did not use elevated 

temperatures resulted in the creation of ASTM C1303, which in 1995 introduced the slicing and 

scaling method, also known as the “thin slicing” method (a technique used to slice the foam so 

that it ages more rapidly as a function of reduced thickness). In contrast to ASTM C578-09, 

ASTM C591-08a, ASTM C1029-08, ASTM C1126-04, and ASTM C1289-08, which specify the 

use of either the 180-day conditioning method or 90-day accelerate conditioning method to age 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
the foam before measuring its thermal resistance. In contrast, the thin slicing method used in 

ASTM C1303-08 (the most recent version of ASTM C1303) was designed specifically to test the 

aging of foam insulation in duration shorter than 180 days, and without the temperature elevation 

methodology used in the 90-day test. (ASTM C1303-08, section 5.3, at p. 3) By reducing the 

length of the pathway for diffusion to take place, the “aging” can be accelerated without the 

confounding effects caused by unique gas properties of the material and blowing agent. The 

results are used to determine the R-value of foam 5 years after manufacture, a value that has been 

shown to correlate strongly with the average R-value of foam 15 years after manufacture. 

(ASTM C1303-08, section 5.4, at p. 3) 

In early 2000, the National Research Council Canada and Institute for Research in 

Construction (NRC-IRC) developed CAN/ULC-S770-00. CAN/ULC-S770-00 incorporated 

elements of ASTM C1303-95 (the first version of ASTM C1303) but altered that standard by 

clarifying the slicing procedure used in ASTM C1303-95, as differing interpretations of the 

previous procedure were thought to be causing variations in the test results among third-party 

testing facilities. These changes sought to eliminate inconsistency in the interpretation of the 

slicing procedure and test setup to ensure uniformity across testing labs. In December 2000, 

CAN/ULC-S770-00 became the Canadian national mandatory test for calculating the LTTR of 

all foam insulation products (this test has since been updated; the most recent version is 

CAN/ULC-S770-03). Members of the U.S.-based Polyisocyanurate Insulation Manufacturers 

Association (PIMA) began to test their products using the same procedure on January 1, 2003. 

The LTTR calculated from this test procedure is used for all building insulation product labeling 

32 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
in Canada and PIMA products in the United States. Also in 2000, ASTM C1303-95 was updated 

as ASTM C1303-00. 

In a 2005 rule by the U.S. Federal Trade Commission (FTC) in which the FTC 

considered requiring ASTM C1303-00 (the most recent version at that time) for product labeling 

on all foam insulation products, the FTC’s review process revealed several unresolved issues 

related to the test procedure. (70 FR 31258 (May 31, 2005); 16 CFR Part 460, Labeling and 

Advertising of Home Insulation: Trade Regulation Rule, Final Rule) Subsequently, ASTM 

C1303-00 was updated to address these issues, which included foam stack composition, 

minimum slice thickness and slice source, the time between manufacture and test initiation, 

preparation of foam-in-place samples, and other clarifications of the procedure. This updated 

version was published as ASTM C1303-08 and is the most recent version of the standard to date. 

Some commenters noted during the framework meeting that the application of an 

impermeable vapor barrier to the surface of the foam could reduce the impact of aging. 

Depending on its end use, foam insulation may have facers or skins applied to act as a vapor 

barrier and/or to enhance the bond of construction glues. Kysor stated that proper use of skins 

eliminates aging and the associated reduction of R-value in polyurethane panels. (Kysor 

(attachment), No. 29 at p. 1) 

DOE examined this issue and found that foams used in walk-in panels are sometimes 

protected by impermeable barriers designed to prevent vapor and/or air exchange into or out of 

the foam or the interior of the walk-in. DOE found research conducted by the National Resource 

33 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
Council Canada (NRCC) suggesting that impermeable facers do not eliminate aging but may 

delay the rate of aging and/or the final equilibrium of the aged state. (Mukhopadhyaya, P.; 

Bomberg, M.T.; Kumaran, M.K.; Drouin, M.; Lackey, J.; van Reenen, D.; Normandin, N., 

“Long-Term Thermal Resistance of Polyisocyanurate Foam Insulation with Impermeable 

Facers”; Mukhopadhyaya, P.; Bomberg, M.T.; Kumaran, M.K.; Drouin, M.; Lackey, J.; van 

Reenen, D.; Normandin, N., “Long-Term Thermal Resistance of Polyisocyanurate Foam 

Insulation With Gas Barrier”; Mukhopadhyaya, P.; Kumaran, M.K. “Long-Term Thermal 

Resistance Of Closed-Cell Foam Insulation: Research Update From Canada”) In one of the 

summary observations of “Long-Term Thermal Resistance of Polyisocyanurate Foam Insulation 

with Gas Barrier,” the NRCC noted, “a considerable amount of aging occurred in thin slice 

specimens despite having untouched impermeable facers, as well as a glass plate at the bottom of 

the specimens and edges sealed completely with epoxy coating.” 

Additionally, the relationship between the skin and the rate of aging in foam depends on 

preserving the integrity of both the skin surface and the bonding between the skin and insulation. 

Punctures, made to allow for the installation of light fixtures, doors, and shelving, undermine the 

integrity of the skin. Walk-in insulation panels and their skins also typically separate over time 

due to shrinkage of foam materials after manufacture. While most foam materials contract by 

less than 1 percent of their total volume, shrinkage at this level is enough to create significant air 

gaps. DOE found that current methods of conditioning foam materials do not account for 

impermeable facers. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Finally, like the conditioning standards that are currently in use, ASTM C1303-08 is not 

designed to test impermeably faced foams that may be used with walk-ins. Significant research 

has been underway by the NRCC but no known test procedure is currently available that 

accounts for the effect of impermeable barriers. DOE requests feedback on this issue, including 

the submission of test results on the impact of impermeable skins on long-term R-value. DOE 

specifically requests that interested parties submit or identify peer-reviewed, published data on 

this issue. 

DOE also requests feedback on the use of ASTM C1303-08 with impermeably faced 

foams. DOE may recommend the use of a test procedure specifically designed for impermeably 

faced foam if one is developed. 

As a result of this evaluation, DOE proposes requiring manufacturers to use ASTM 

C1303-08 to determine the LTTR of walk-in foam insulation for the purposes of calculating the 

energy consumption of walk-in equipment. DOE requests comments on this proposal. 

DOE is also proposing and seeking comment on the following exceptions to ASTM 

C1303-08: 

(1) Section 6.6.2 of C1303-08 suggests that two standards for measuring the thermal 

resistance may be used. DOE proposes to allow use only of ASTM C518-04 (in EPCA, an 

incorrect form of the date suffix was used, e.g., ASTM C518-[20]04), as specified in EPCA. (42 

U.S.C. 6314(a)(9)(A)(ii)) 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
(2) In section 6.6.2.1, in reference to ASTM C518-04, the mean test temperature of the 

foam during R-value measurement would be -6.7 +/- 2 °C (20 +/- 4 °F) with a temperature 

difference of 22 +/- 2 °C (40 +/- 4 °F) for freezers and 12.8 +/- 2 °C (55 +/- 4 °F) with a 

temperature difference of 22 +/- 2 °C (40 +/- 4 °F) for coolers. This change replaces the standard 

mean temperature of 75 °F for ASTM C518-04 with the EPCA specified values. 

(3) For the purposes of preparing samples with foam-in-place method, section A2 should 

be followed exactly except for the following modifications to accommodate foam-in-place 

methods that may be used during the manufacture of walk-in panels: 

(3.1) Instead of following A2.3, which specifies that the foam be sprayed onto a 

single sheet of wood, the sample shall be foamed into a fully closed box of 

internal dimension 60 cm x 60 cm by desired product thickness (2ft x 2ft x 

Desired thickness). The box shall be made of 3⁄4 inch plywood and internal 

surfaces wrapped in 4 to 6 mil polyethylene film to prevent the foam from 

adhering to the box material. 

(3.2) Instead of following section A2.4,which specifies the spraying of foam 

layers onto a open sheet of plywood, the cavity shall be filled using the 

manufacturer’s typical foam-in-place method through a standard injection port or 

other process typically used to foam the product being tested. 

(3.3) In section A2.6, which defines the single surface in contact with the board to 

be the “surface,” the definition of the foam’s “surface” shall be the two surface 

regions in contact with the 60 x 60 cm sections of the box. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
(3.4) Section A2.8 shall not be followed because the prepared sample will not 

have any “free rise” component. 

DOE proposes that manufacturers select foam test thicknesses based on design 

specifications and practice. If a foam’s thickness as manufactured varies from the tested product 

thickness, DOE proposes that the R-value of that foam at its manufactured thickness may be 

interpolated using the results of ASTM C1303-08, provided that the manufactured thickness does 

not vary from the tested product thickness by more than ±0.5 inches. For example, if 4-inch and 

6-inch products were prepared, interpolation between 3.5 and 4.5 inches would be allowed for 

the 4-inch foam and 5.5 and 6.5 inches for the 6-inch foam. If the manufacturer determines that 

final foam thickness should be outside of the tested range, then additional testing would be 

necessary to fit the criterion for interpolation. Manufacturers should make their sample selections 

accordingly to avoid the need for additional testing. DOE requests feedback on the use of 

interpolation within the specified ±0.5 inch range. 

DOE proposes that the results for each of the sample sets of three stacks should be 

reported as specified by ASTM C1303-08. As defined by ASTM C1303-08, after thin slices of 

foam are cut, the slices are organized into “stacks” of slices to match the original overall 

thickness of the sample. The procedure defines three stack types: (1) stacks comprised of only 

surface slices of foam, (2) stacks of only core slices and (3) a mixture of core and surface slices. 

A “surface” slice and a “core” slice are defined in ASTM C1303 as “a thin-slice foam specimen 

that was originally adjacent to the surface of the full-thickness product and that includes any 

facing that was adhered to the surface of the original full-thickness product” and “a thin-slice 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
foam specimen that was taken at least 5 mm (0.2 in.) or 25% of the product thickness, whichever 

is greater, away from the surface of the full thickness product” respectively. The R-value of only 

the mixed stack would be used to calculate the energy performance of walk-ins. DOE requests 

feedback on this approach. ASTM is currently conducting a 5-year “ruggedness” test. Upon 

completion of the test, DOE may consider a rulemaking to modify the required number of stacks 

and/or which stack is best suited for labeling and calculating energy performance. DOE requests 

feedback on the use of the mixed stack R-value for the purpose of calculating walk-in energy 

use. 

Additionally, DOE notes that ASTM C1303-08 is specifically intended for measuring the 

LTTR of foam materials. In light of this situation, the process contained in this standard would 

not apply to advanced insulation technologies such as vacuum insulated panels (VIPs) or 

aerogels. However, ASTM C518-04 can be used to measure the thermal properties of these new 

technologies, which, as specified in EPCA, is the required test for measuring insulating 

performance. (42 U.S.C. 6314(a)(9)(A)(ii)) DOE requests feedback on whether non-foam 

advanced technologies, such as VIPs or aerogels, would be likely to be used for walk-ins in the 

next 5 years. If DOE determines that these materials may be used in walk-ins in the next 5 years, 

DOE may consider alternative test procedures for capturing the long-term insulating value of any 

non-foam materials. 

ii. Water Absorption in Foam 

At the framework public meeting, interested parties raised the issue of R-value 

deterioration in foams due to moisture absorption. Craig stated that moisture penetration causes a 

38 

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decline in the R-value of foam insulation, at a rate that depends on the type of foam used. (Craig, 

No. 22 at p. 3) As is the case with aging, insulating foams exhibit different characteristics in the 

presence of moisture. Polystyrene foam is highly resistant to water absorption, whereas 

polyurethanes and polyisocyanurates are more easily damaged by exposure to moisture. In 

general, the solution to moisture issues involves creating an impermeable barrier between the 

insulation and the moisture source. However, Owens Corning asserted that customers routinely 

puncture metal skins to allow for the installation of lighting fixtures, shelving, and doors, 

creating holes that allow moisture to enter the insulation. (Owens Corning, Public Meeting 

Transcript, No. 15 at p. 61) 

Although vapor permeance and water absorption tests exist, they are designed for 

measuring specific material properties rather than measuring system performance of composite 

structures like walk-ins. For a variety of reasons, these tests would be complex, costly, and time 

consuming to use because several sub-methods would need to be developed to quantify the 

impact of water on walk-ins. For every unique construction method and/or combination of 

materials (e.g., blowing agent, foam type, barriers, gasketing materials, panel joint type and 

method), the following considerations exemplify the challenges inherent in accounting for and 

quantifying insulating performance: (1) the rate at which the walk-in envelope collects water 

over its life must be measured or predicted using an accelerated test; (2) a saturation level or 

maximum absorption, if any, must be determined; and (3) a correlation between water absorption 

levels and insulation performance must be quantified. At this time, test procedures for each of 

these considerations are not yet recognized by a nationally recognized organization such as 

ASTM. 

39 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE reviewed several methods for testing vapor permeance and water absorption in 

foam insulation materials including ASTM E96, “Standard Test Methods for Water Vapor 

Transmission of Materials,” ASTM C209, “Standard Test Methods for Cellulosic Fiber 

Insulation Board,” ASTM C272-01(2007), “Standard Test Method for Water Absorption of Core 

Materials for Structural Sandwich Constructions,” and ASTM D2842-06, “Standard Test Method 

for Water Absorption of Rigid Cellular Plastics.” Each of these standards describes a method for 

submerging a sample in water for a specified amount of time and then measuring the amount of 

water absorbed on a volume or weight basis. However, each one specifies significantly different 

immersion durations (ranging from 2 to 96 hours) and methods of weighing samples (blotting 

surfaces before measurement or using a buoyancy measurement). DOE believes that using the 

longest test period, 96 hours, would likely result in near worst case or maximum water 

absorption, but it is unclear how this directly translates to reduction in insulation performance for 

various materials. 

Additionally, ASTM E96-05 measures vapor permeance under low vapor pressure 

gradient conditions. However, the temperature differentials in which walk-ins operate cause a 

high vapor pressure gradient, which has the effect of continuously driving moisture through the 

envelope. Neither ASTM E96-05 nor any other known procedures currently provide a 

methodology to accurately calculate the vapor permeance in walk-ins at the pressure gradients 

typically experienced in the field. 

40 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
Some research has been completed, including a major study by the Cold Regions 

Research and Engineering Lab (CRREL). The CRREL study developed and applied a method for 

creating a vapor pressure gradient across various materials to quantify the rate at which these 

materials absorb and retain water over time. The insulating performance of the materials was 

also tested at various levels of moisture content to develop equations for the purpose of 

calculating the insulating properties at any moisture percentage relative to its dry weight. No 

other testing body has applied CRREL’s testing procedures to replicate the results and most of 

CRREL’s research was completed nearly 20 years ago. One of DOE’s national labs has also 

begun development of procedures to evaluate the impact of moisture on insulation R-values, but 

this activity remains incomplete. 

Given the discussion above, DOE does not propose to include the impact of water 

absorption on R-value in the test procedure because no well-accepted method has been 

developed. However, DOE will evaluate such a procedure if it is developed in the future. 

b. Air Infiltration 

Another major pathway for energy loss in walk-ins is air infiltration, or air exchanged 

into and out of a walk-in while all access points are closed or during door-opening cycles (i.e., 

the openings of doors for the removal or stocking of product, or passage of customers, personnel, 

and/or machinery, also referred to as “door-opening events”). Compared with other energy 

consumption factors such as conduction losses through insulation, air infiltration may be the 

largest contributing factor to envelope energy losses. Air infiltration can occur through steadystate leakage or from door opening events. As a result, designs and technologies that reduce 

41 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
infiltration during steady-state operation and door-opening events should be considered to reduce 

these losses. 

EPCA includes prescriptive requirements for doors used on walk-ins, recognizing that a 

major portion of energy is lost through door opening cycles. All walk-in coolers or freezers 

“manufactured on or after January 1, 2009, shall (A) have automatic door closers that firmly 

close all walk-in doors that have been closed to within 1 inch of full closure, except ... doors 

wider than 3 feet 9 inches or taller than 7 feet; [and] (B) have strip doors, spring hinged doors, or 

other method of minimizing infiltration when doors are open ....” (42 U.S.C. 6313(f)(1)) During 

the framework public meeting, interested parties suggested methods for calculating infiltration 

from door-opening events within the test procedure. 

These two infiltration pathways, steady-state leakage, and air losses due to door-opening 

events, are mitigated using distinct methods. 

Steady-state infiltration (the air exchanged between the interior and exterior of a walk-in 

while all doors are closed, also referred to as “leakage”) occurs because of the significant 

pressure gradient caused by the large temperature difference between the refrigerated space and 

the external environment. This pressure differential continuously induces air movement from the 

outside to the inside of a walk-in where leakage pathways exist. Leakage typically occurs 

through door frames, door gaskets, wall panel-to-panel interfaces, and wall-to-floor and wall-toceiling junctions. While considered minimal for small walk-ins, leakage becomes more 

significant as the walk-in size increases. 

42 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
Air infiltration due to door openings is mostly a function of door area, opening frequency, 

duration, and air density. The primary means of reducing the amount of infiltration is by the use 

of active or passive infiltration reduction devices and devices that help reduce the time that doors 

are left accidentally ajar. Air curtains and strip curtains are good examples of active versus 

passive devices. The sections below describe the methods for testing the effectiveness of such 

devices and procedure for calculating air infiltration’s impact on energy use in walk-ins. 

Hired Hand recommended that the energy analysis for warehouse coolers and freezers 

include the performance of the door, including the number of door-opening cycles each day or 

week and factoring in optional door configurations such as automatic doors with or without strip 

curtains. (Hired Hand, No. 27 at p. 1) Eliason recommended that DOE consider average door 

cycling and door-ajar conditions in its test procedure. (Eliason, No. 19 at p. 1) Eliason noted that 

both of these conditions are part of the company’s internal life-cycling test and represent realworld conditions. (Eliason, No. 19 at p. 1) Hired Hand stated that a simple rating for door 

infiltration performance could be based on door-opening cycles per week. (Hired Hand, No. 27 

at p. 2) Hired Hand also suggested that DOE require consumer labeling to indicate the cost per 

minute of leaving the door open based on door size and application. (Hired Hand, No. 27 at p. 2) 

Based on stakeholder comments and DOE review of the impact of air infiltration on 

energy use, DOE identified two methods that could be used to measure air infiltration in walkins: the blower door method and the gas tracer method. These methods are described in the 

following subsections. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
i. Blower Door Method 

DOE reviewed ASTM E1827-96(2007), “Standard Test Methods for Determining 

Airtightness of Buildings Using an Orifice Blower Door,” as a possible candidate test procedure 

for testing walk-ins. This method pressurizes or depressurizes the internal space using a large 

fan, typically placed in a doorway. The infiltration rate of the space can be directly calculated by 

measuring the pressure difference between the exterior and interior space and the air-flow rate 

through the fan. 

After reviewing this test method, DOE identified reasons why the test might not be 

suitable for walk-ins. The blower door method is better suited for structures with relatively high 

rates of infiltration, such as buildings and homes, rather than the relatively low levels typically 

observed in walk-ins. In addition, known calibration curves for the blower door method require 

small temperature differentials (generally less than 10 F) between the inside and outside of the 

envelope. However, walk-ins typically operate with a far greater differential that is normally 

greater than 40 F. Another drawback to using this method with walk-ins is that the test setup 

procedure requires blocking a main entrance to the structure with the blower door. Because 

infiltration around the main door is a key source of infiltration in walk-ins and would not be 

measured as part of the test, this approach would not adequately capture the majority of the 

infiltration. For these reasons, DOE does not propose the use of the blower door method for 

measuring the air infiltration of walk-ins. 

ii. Gas Tracer Method 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE also reviewed ASTM E741-06, “Standard Test Method for Determining Air Change 

in a Single Zone by Means of a Tracer Gas Dilution.” Although not as widely used as the blower 

door method, the gas tracer method has been used for decades by the building industry. The test 

is conducted by injecting a tracer gas, such as carbon dioxide or perfluorocarbons, into the 

internal space and measuring its concentration at recorded times. From these measurements, the 

average air change rate can be determined. While manual tools, such as syringes, or automated 

systems can be used to sample the air spaces, the test procedure lends itself to automation both 

for calibration and data collection. Depending on the gas and sampling method used, the gas 

concentration can be measured immediately with portable equipment. This method is also more 

accurate than the blower door method because it allows for direct measurement of infiltration 

without modification of the design conditions. (ASTM, ASTM E741-06 (2006), “Determining 

Air Change in a Single Zone by Means of a Tracer Gas Dilution,” section 5.6, p. 3) 

c. Steady-State Infiltration Test 

For the reasons described above, DOE proposes using the gas tracer method described in 

ASTM-E741-06 for measuring the steady-state air infiltration of walk-ins, with the following six 

exceptions. 

First, DOE proposes using the “concentration decay method” instead of other available 

options described in ASTM E741-06. DOE considers this method to be the simplest, fastest, 

most cost efficient, and most accurate. 

45 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
Second, carbon dioxide (CO2) is the recommended gas tracer for all testing because of 

the few human hazards related to its use, and the availability and relative cost of sampling 

equipment. 

Third, the test would use the “average air change rate” method, in changes per hour (1/h), 

rather than the “average air change flow” method described in ASTM E741-06. The “air change 

flow” method allows for the direct measure of the exchange of air in cubic feet per hour and does 

not require measurement of the internal volume of the space but requires a more complex test 

setup and sampling method. In contrast, the “air change rate” method measures the rate of 

exchange of air per unit of time can be completed using relatively simple equipment. However, 

converting this value to a measurement of the flow, e.g., volume of air exchanged per unit time, 

requires a precise measurement of internal volume. Since the precise internal volume of a given 

walk-in is readily available, DOE considers the “air change rate” method preferable to the “air 

change flow” method because the equipment is less expensive and the measurements are easier 

to obtain. 

Fourth, ASTM E741-06 describes the importance of verifying proper gas mixing but does 

not describe where or how many spatial locations should be sampled. DOE proposes that spatial 

measurements shall be taken in a minimum of six locations or one location per 20 square feet 

(ft2

) of floor area (whichever results in a greater number of measurements), at a height of 3 ft +/- 

0.5 ft, or a minimum of 2 ft +/- 0.5 ft from the inside wall of the walk-in envelope, to verify that 

the air space is uniformly mixed. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Fifth, DOE proposes the test be completed close to operational temperature to mimic the 

thermally induced pressure gradient seen in walk-ins. The internal air temperature shall be -23.3 

(-10 °F) +/- 2 °C (4 °F) for freezers and 1.7 (35 °F)+/- 2 °C ( 4 °F) for coolers. The external air 

temperature should be 24 °C (75 °F) +/-2.5 °C (5 °F). 

Sixth, the test should be completed with all doors closed. The resulting measurement 

shall be in units of changes per hour. 

DOE requests feedback on its proposal to use ASTM E741-06 as the method for 

determining air infiltration and on the proposed exceptions to the test procedure. 

For the purposes of administering the test, DOE considered the following options for the 

location of the test: (1) require testing at a third-party testing facility. DOE believes that 

requiring that manufacturers to ship every walk-in manufactured, or a representative model, to a 

third-party facility for testing, would place a substantial burden on manufacturers; (2) require 

testing by a third party on site at a walk-in manufacturing facility. Completing the infiltration test 

at the manufacturing facility reduces logistical complexity and costs associated with testing. 

Since the equipment used to complete infiltration testing was originally designed for testing the 

performance of buildings, the equipment and protocols are designed to be mobile. 

DOE believes that the most viable option is allowing testing to occur at the 

manufacturing facility, if preferred by the manufacturer. DOE requests feedback on the 

flexibility of location required for completion of any infiltration test. 

47 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
iii. Door Infiltration Reduction Device Test 

DOE is considering incorporating a door-opening test to quantify the impact of 

technologies such as strip curtains, air curtains, or other infiltration reduction devices during 

door-opening events. Due to the limited data available on these devices and the variety of 

technologies, DOE believes a standardized test would provide a more comprehensive and 

accurate picture regarding the effectiveness of these devices when compared to simply using 

effectiveness assumptions 

DOE proposes a two-part test to account for the effect of the door infiltration reduction 

device. First, measurements should be taken once the tracer gas has uniformly dispersed in the 

internal space using the methodology described in ASTM E741-06. Within 3 minutes +/- 30 

seconds, with the infiltration reduction device in place, a door should be opened at an angle of 90

degrees over a period no longer than 3 seconds, then held at 90 degrees in the open position for 5 

minutes +/- 5 seconds, then closed over a period no longer than 3 seconds. The gas concentration 

should be sampled again after the door has been closed. Samples should continue being taken 

until the gas concentration is once again uniformly mixed within the walk-in. Second, the test 

should be repeated exactly as described above with the infiltration reduction device removed or 

deactivated. 

Using the measured infiltration with the device in place and without the device in place, 

the infiltration reduction effectiveness can be directly calculated: 

48 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
Vrate,withdevice E  100% Eq. 1 Vrate,without device

Where: 

Vrate,with-device = air infiltration rate, with door open and reduction device active, using 4.2, 1/h; 

Vrate,without-device = air infiltration rate, with door open and reduction device disabled or removed, 

using 4.2, 1/h. 

This calculation will yield a value between 0 and 100 percent, with 100 percent meaning 

that the device prevents all air infiltration when the door is open. DOE proposes using this 

calculated effectiveness for every unique door-device combination that a manufacturer may 

offer. DOE requests feedback on the proposed method for measuring the effectiveness of an 

infiltration reduction device. 

iv. Infiltration Due to Door Openings 

DOE does not propose to require manufacturers to measure the infiltration from all dooropening events. The complexity of testing, the variation of walk-in design, and various end-use 

behavior factors would make such a recommendation very difficult to execute. Instead, DOE 

proposes using analytical methods based on equations published in the ASHRAE Refrigeration 

Handbook in combination with assumed door-opening frequency, and duration of door cycles, to 

calculate the air infiltration associated with each door-opening event. 

ASHRAE recommends using Gosney and Olama’s (1975) air exchange equations for 

fully established flow through door openings (Equation 2). Several key assumptions have the 

49 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
greatest impact on predicated air exchange and are related to the calculation of the decimal 

portion or time a doorway is open, Dt. (ASHRAE, Refrigeration Handbook, 2006, section 13.5) 

P   p 	 60  o 
 Dt  Eq. 2 3600  d 


Where: 

Dt,= fractional door opening, 

P = the number of doorway passages (or number of door-opening cycles for a given door), 

p = the door open-close time, 

o = the time the door stands open, and 

d = daily time period. 

Dt is important for properly calculating the energy impact of air infiltration due to dooropening events. Therefore, the assumed values of P, p, and o will drive the result. The daily 

time period, d, is simply assumed to be 24 hours. 

For display glass doors, a P of 72 per day, p of 8 seconds per passage, o of 0 minutes 

and d of 24 hours could be used. P of 72 per day is based on comments by Hired Hand and 

research on cold store infiltration. Hired Hand commented that the reach in frequency is 

approximately 400-600 per week (or one passage every 20 minutes assuming 18 hours per day 

per week). (Hired Hand, Public Meeting Transcript, No. 15 at p. 154) However, DOE identified 

a study by A. R. East, P. B. Jeffrey, and D. J. Cleland, “Air Infiltration into Walk-in Cold 

Rooms,” which suggested that this number should be closer to one passage every 10 minutes 

(assuming 18 hours per day per week). DOE suggests that the average of the two values of one 

50 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
passage every 15 minutes or P of 72 per day could be used. DOE chose the value of 8 seconds 

per passage but seeks comment on whether another value may be more appropriate. 

For all other door or access types, a P of 60 per day, p of 12 seconds per passage, o of 

15 minutes, and d of 24 hours could be used. The number of passages reflects that other door 

types are typically accessed less frequently than glass doors. The value of 12 seconds per passage 

was selected based on the assumption that non-glass doors, such as those through which forklifts 

are driven in order to load product, will be open for longer periods of time than a typical display 

door. DOE selected the o of 15 minutes due to the probability that a non-glass door will be 

propped open accidentally or intentionally. If an automatic door opener/closer is used for doors 

larger than 7 feet tall and 3 feet, 9 inches wide, then a p of 10 seconds should be used. 

DOE recognizes that with the variety of walk-in types and end-users, the frequency and 

duration of door-opening events is likely to vary significantly. As a result, DOE requests 

comments on the DOE assumed values for P, p, and o. 

3. Calculations 

In this section, DOE proposes a calculation methodology for using the results obtained 

from the measurements in the aforementioned tests, along with other known quantities, to 

calculate an energy use metric associated with the envelope. The steps in the proposed 

methodology are explained below. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
a. Energy Efficiency Ratio 

EPCA requires that the test procedure “measure the energy use of walk-in coolers and 

walk-in freezers.” (42 U.S.C. 6314(a)(9)(B)(i)) However, EPCA does not specify the units of 

measurement or units for reporting that are required. Based on a review of commonly used 

energy consumption metrics, DOE recommends the use of kWh/day as this unit is commonly 

recognized by end-users, manufacturers and other interested parties. However, a majority of 

metrics used to describe heat transfer losses are in units of British Thermal Units (BTU) per unit 

time. Therefore, to convert the British Thermal Units per hour (BTU/h) thermal energy 

transmission calculation into a measure of electrical energy consumed by the refrigeration 

equipment to remove the heat, DOE proposes using an energy efficiency ratio (EER) conversion 

based on a nominal efficiency of an assumed refrigeration system. 

Because an envelope manufacturer cannot control where the refrigeration equipment is 

sited and the EER is intended to provide a means of comparison and not directly reflect a real 

walk-in installation, DOE proposes that the EER be 12.4 Btu per Watt hour (Btu/W-h) for 

coolers and 6.3 Btu/W-h for freezers. The difference in EER for coolers and freezers reflects the 

relative efficiency of the refrigeration equipment for the associated application. As the 

temperature of the air surrounding the evaporator coil drops (that is, when considering a freezer 

relative to a cooler), thermodynamics dictates that the system effectiveness at removing heat per 

unit of electrical input energy decreases. DOE requests feedback on the relative EERs of 

refrigeration equipment for a comparison basis 

52 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
b. Heat Gain through the Envelope due to Conduction 

The energy calculation for all components that comprise the external surface area of the 

walk-in may be determined using the measured surface area, the measured foam R-value for the 

walls and ceiling, the R-value (or U-value) for glass doors, the design operation temperature, and 

the average ambient air temperature. Then, the associated heat transfer due to conduction can 

then be directly calculated. 

i. Conduction through Glass Display Doors 

The heat conduction through the glass is one of the largest single contributors to energy 

consumption for walk-ins with a high ratio of glass surface area to non-glass surface. The 

thermal conductivity, the inverse of thermal resistivity or R-value, is commonly represented by 

the U-value in units of Btu/ft2-°F-h. The thermal conductivity for most glass products, such as 

glass doors and windows used in buildings, is certified by a third party organization such as the 

National Fenestration Rating Council (NFRC). After certification, the product is granted a NFRC 

label and thermal conductivity performance rating. This rating represents an overall component 

performance including but not limited to the glass and the glass frame. However, in the case of 

glass products manufactured for the use in walk-ins, such as display doors, inset window and 

glass walls, DOE believes that glass component manufacturers currently do not participate in any 

third party rating programs nor do they provide products with performance labels. In addition, 

the performance data of these products is not readily available able in product literature. 

In order for the thermal conductivity performance of glass products be incorporated into 

the walk-in test procedure, DOE proposes these two options: (1) If manufacturers of glass doors 

53 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
used in walk-ins participate in the same NFRC rating program, the performance of the door shall 

be simply read from its label and used for calculations in this test procedure. If glass door 

manufacturers do not participate in the same NFRC rating program, then (2) DOE would require 

manufacturers to use the free software package Window 5.2 (available here: 

http://windows.lbl.gov/software/window/window.html), that calculates the U-value, or thermal 

conductivity, of a glass door given precise specifications such as the size of the door, the number 

of panes of glass, the gas fill between the panes, etc. This tool was developed by Lawrence 

Berkeley National Lab (LBNL) and is known in the glass component industry to accurately 

predict glass door thermal performance from the given door characteristics. It has been used for 

many years and has been heavily verified by empirical test data. In order to ensure that inputs 

used to calculate overall door performance are not being manipulated by manufacturers, DOE 

intends to require the walk-in manufacturer to report the exact inputs and settings used in 

Window 5.2 to represent the door materials and glazing system. This will ensure transparency 

and accuracy by enabling other manufacturers and DOE to verify the integrity of the data and 

calculated performance. 

DOE seeks comment on the availability of performance data on glass products used in 

walk-in applications, glass component manufacturers’ participation in third party certification 

programs such as NFRC, and the proposed method for predicting the thermal performance of 

glass components using LBNL’s Window 5.2 software package. 

ii. Conduction through Floors 

54 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
In general, walk-in coolers are installed on top of concrete surfaces regardless of the 

walk-in type. For a walk-in cooler that does not have a floor supplied by the manufacturer, the 

average insulating performance of concrete will be assumed for the floor surface of the walk-in. 

Therefore, DOE proposes using an R-value of 0.6 ft2

-F-h/Btu for calculating the energy lost 

assuming the walk-in cooler are sited on 6-inch concrete floors of 150 lb/ft3

 density (ASHRAE 

Fundamentals Handbook). DOE requests feedback on the use of this R-value for coolers that are 

not shipped with an insulated floor. 

Generally, walk-in manufacturers that sell large freezers do not install freezer floors. This 

task is normally subcontracted by the end-user before the walk-in is installed to ensure EPCA 

compliance. Therefore, DOE proposes using the minimum R-value specified in EPCA for walkin freezer floors, R-28 ft2

-F-h/Btu, for energy performance calculations if the manufacture does 

not supply a floor to ensure EPCA compliance. (42 U.S.C. 6313(f)(1)(D)) DOE requests 

comments on the use of this proposed R-value for freezer floors. 

c. Heat Gain Due to Infiltration 

The amount of embodied energy in an air sample is primarily a function of its 

temperature and density or what is typically referred to as the enthalpy in a thermodynamic 

system such as a walk-in. The required amount of energy needed to remove heat from the air is 

calculated as the difference between the enthalpy of air entering the refrigerated space and 

enthalpy of the air inside the refrigerated space. This calculation is commonly used when 

designing walk-ins and typically uses dry-bulb and wet-bulb temperatures. The difference, per 

unit mass or volume of air, is calculated using the functional relationship between temperature 

55 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
and enthalpy. Using the measured infiltration rate from the required steady-state test described 

above or calculated analytical value for air infiltration for door-opening events and the calculated 

internal and external enthalpy, a rate of energy lost per hour (Btu/h) due to air exchange can be 

calculated. 

d. Envelope Component Electrical Loads 

Because the energy use of the walk-in refrigeration equipment is being analyzed 

separately from the envelope energy use, DOE is considering calculating the electricity 

consumption of lights, sensors, and other miscellaneous electrical devices using name-plate 

rating and assumptions about their daily operation, all of which would be incorporated into the 

evaluation of envelope energy use. In addition, because the test procedure for the refrigeration 

system will not include heating loads caused by lighting, heater wires, and other miscellaneous 

components, the thermal load from these components will be factored into the envelope 

calculations. DOE proposes as part of the test procedure calculations that 100 percent of the 

electrical energy consumed to operate the devices that are internal located in the walk-in, will be 

converted to thermal energy. This assumption is accurate since at steady-state, all the input 

electrical energy is converted completely into heat adhering to the physical laws of conservation 

of energy. While some electrical energy, which has been converted into light, may escape the 

controlled space via translucent glass display doors, this escaping energy is negligible. The 

associated thermal energy will then be used to calculate an additional compressor load that 

would be required to remove the additional heat generated by these components 

56 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE recommends using the following equation to calculate the power usage for each 

electricity-consuming device type, Pcomp, (kWh): 

Pcomp ,t  Prated ,t  (1  PTOt )  nt  24 Eq. 3 

Where: 

Prated,t = rated power of each component, 

PTOt = percent time off, and 

nt = the number of devices at the rated power. 

DOE proposes that the rated power must be read from each electricity-consuming device 

product data sheet or name plate, and the nt is the number of identical devices for which the Pcomp 

calculation is being made. 

DOE further proposes the use of the following equation to calculate additional 

compressor load due to heat generated by electrical components, Cload, (kWh): 

3.412 Btu Cload  Ptot,int  Eq. 4 EER Wh

Where: 

EER= EER of walk-in (cooler=12.4 or freezer=6.3), Btu/W-h 

Ptot,int= The total electrical load due to components sited inside the walk-in 

envelope 

The percent time off (PTO) value accounts for the reduction in energy use in walk-ins 

with component control systems installed and to specify the possible number of hours for various 

component types. While this value may not reflect behaviorally related energy consumption, 

such as how long an end-user typically leaves the lights on, it will provide a means for 

57 

EERE-2008-BT-TP-0014 DOC ID 1.1.001
comparison of walk-in performance. To address the wide variety of devices that could be 

employed in a walk-in unit, DOE proposes the following PTO values: 

(1) For lights, DOE proposes a PTO value of 25 percent for systems without timers or 

other auto shut-off systems and 50 percent for systems with timers or other auto shut-off systems 

installed. 

(2) For anti-sweat heaters, DOE proposes a PTO value of 0 percent for all systems 

without direct or indirect relative humidity sensing controls. DOE further proposes that a PTO 

value of 75 percent be used for walk-in coolers, and 50 percent for walk-in freezers with these 

controls. (Focus on Energy, BP-3429-0304, “Anti-Sweat Heater Controls,” 2004, p. 1) 

(3) For electrically powered devices (such as air curtains) that mitigate air infiltration but 

are not actively controlled based on door open or closed positions, DOE proposes a PTO value of 

25 percent. 

(4) For electrically powered devices that mitigate air infiltration that are also actively 

controlled based on door open or closed position for display doors, DOE proposes a PTO value 

of 99.33 percent. 

(5) For electrically powered devices that mitigate air infiltration that are also actively 

controlled based on door open or closed position for all other doors, DOE proposes a PTO value 

of 99.17 percent. 

(6) For all other devices, DOE proposes a PTO value of 0 percent, unless the walk-in 

manufacturer can demonstrate that the device is controllable by a preset control system. If this 

can be demonstrated, then DOE proposes a value of 25 percent for the device in question. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
DOE seeks comments on these assumptions. 

e. Normalization 

A single metric would make comparing the energy use of walk-ins much more 

straightforward. DOE proposes using a calculation for energy consumption per unit time and a 

normalization factor to account for differences in glass and non-glass external surface area 

depending on the product class. During the framework public meeting and in written comments, 

some interested parties recommended that DOE use volume as the normalization factor for 

performance standards. (Manitowoc, Public Meeting Transcript, No. 15 at p. 56; EEI, Public 

Meeting Transcript, No. 15 at p. 116; NEEA, No. 18 at p. 3)) Crown Tonka, in a written 

comment, recommended that the test metric be kWh per cubic foot (i.e., energy consumption 

normalized by volume). (Crown Tonka, No. 23 at p. 1) The Joint Comment recommended that 

DOE use surface area as the normalization factor. (Joint Comment, No. 21 at p. 2) A comment 

submitted jointly by representatives of SCE, SMUD, and SDG&E (hereafter referred to as the 

Utilities Joint Comment) also stated that DOE should use surface area as a normalization factor. 

(Utilities Joint Comment, No. 32 at p. 7) 

Many established metrics use a per-day time scale normalized by product volume. 

However, surface area is the key geometric characteristic related to both conduction and 

infiltration because volumetric normalization cannot directly account for the higher conduction 

and infiltration losses associated with glass doors and windows. Conduction and infiltration 

losses through glass become particularly important considerations as the ratio of glass door area 

to total wall area increases, as is the case in walk-ins designed for customer access. Using surface 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
area as the normalization factor would account for these losses through any glass door or 

window used in a walk-in. Therefore, DOE proposes the use of surface area as a normalization 

factor for performance calculations of walk-ins. DOE requests comments on this proposed 

normalization method. 

f. Daily Energy Consumption Coefficients 

As discussed in section III.A.1, DOE proposes allowing manufacturers to group similar 

units together into a single “basic model.” This approach would reduce the testing burden as only 

one unit of each basic model would be subject to testing. However, in the case of envelopes, the 

equipment is so highly customized that each unit a manufacturer builds may be unique. For 

example, units may have identical materials, components, or construction methods, but may be 

built to varied dimensions, which could result in different energy consumption values being 

obtained using the proposed test methods. 

In order to compare units that are similar enough to be included in the same basic model, 

but that are not identical, the test procedure allows for calculating daily energy consumption 

coefficients (or DECCs), using test results from a particular unit within a basic model, and then 

applying these DECCs to other units within a basic model to calculate the energy consumption of 

the other units. DECCs are essentially scaling factors that allow a manufacturer to change certain 

parameters of an envelope and calculate the corresponding change in energy consumption. In the 

case of today's proposed procedure, these parameters would be wall surface area, non-glass door 

surface area, glass display door surface area, glass wall and inset window surface area, 

infiltration due to opening of non-display type doors and infiltration reduction due to reduction 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
devices in place on non-display doors, infiltration due to opening of display type doors and 

infiltration reduction due to reduction devices in place on display doors, and electrical energy 

consumption due to devices including, but not limited to, lights, anti-sweat heaters, and motors to 

drive air mixing fans. The expression for daily energy consumption is formulated on the 

assumptions that: (1) energy consumption due to conduction losses scales linearly with surface 

area; (2) energy consumption due to infiltration scales linearly with the number of doors of each 

type and total wall surface area; (3) energy consumption of anti-sweat door heaters scales 

linearly with total door surface area; and (4) energy consumption of other electrical components 

including lighting and stirring fans scales linearly with the interior volume of the envelope. 

Once the DECCs are calculated from a tested walk-in envelope, they are combined to 

provide a linear expression of the daily energy consumption of any walk-in envelope of the same 

basic model as the tested envelope (that is, having the same construction methods, materials, 

components, and other energy consumption characteristics as the tested envelope), as follows: 

E tot,system non-glass non-glass,tot glass glass,tot infilt,disp_dr_opn disp_doors  DECC  A + DECC  A + DECC  A +

DECC disp_dr_device disp_doors infilt,non-display,dr_opn non-display-doors non-display-dr_device non-display-doors  n 	 DECC  A + DECC  n 	

DECC light ref_space ASH disp_doors stir_fan ref_space other ref_space  V + DECC  A + DECC  V + DECC  V

Eq. 5 

where: 

DECCnon-glass= DECC for non-glass, 

Anon-glass,tot= total non-glass surface area, 

DECCglass,door= DECC for glass doors, 

Aglass,glass, tot= total glass surface area, and 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
DECCglass,wall= DECC for glass walls and inset windows, 

Aglass,wall, tot= total glass wall and inset window surface area, and 

DECCinfilt,disp_dr_opn= DECC for opening of display type doors, 

Adisp_doors= total area of display doors, 

DECC disp_dr_device= DECC for infiltration reduction device in place for display doors, 

 ndisp_doors= total number of display doors, 

DECCinfilt,non-display_,dr_opn = DECC for non-display type doors, 

Anon-display_doors= total area of non-display type doors, 

DECCnon-display_dr_device= DECC for infiltration reduction device in place for non-display 

doors, 

 nnon-display_doors= total number of non-display doors, 

DECClight= DECC for lights, 

Vref_space= total enclosed refrigerated volume(ft3

), 

DECCASH= DECC for anti-sweat heaters, 

DECCstir_fan= DECC for motors used to drive air mixing fans, and 

DECCother= DECC for other electricity consuming devices. 

Only applicable DECCs shall be used. For example, if a certain basic model did not have 

glass display doors, DECCs and variables pertaining to glass display doors would not be 

calculated, nor would they be included in the equation of energy consumption. 

DOE believes that this approach would reduce the testing burden on manufacturers 

because it would not require manufacturers to test every unit produced with slight variations due 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
to customer specification. However, by specifying a calculation methodology that manufacturers 

must use, the approach reduces the potential for inconsistency among manufacturers’ rating 

methods, a concern that interested parties raised about DOE’s previous idea to allow each 

manufacturer to develop its own AEDM for rating similar, but not identical, equipment. (See 

section III.A.3 for discussion of comments about this issue). DOE requests comment on the 

proposed approach of specifying a formula based on DECCs, and on the assumptions that DOE 

made in generating this formula. DOE also asks if there are other parameters it should consider 

when calculating DECCs. 

C. Refrigeration System 

As previously discussed, a differentiation was made for the purposes of this test 

procedure between the envelope or structure of the walk-in cooler or freezer and the mechanical 

refrigeration system performing the physical work necessary to cool the interior space. The 

refrigeration system in this context is further subdivided into three categories, consisting of 

single-package systems containing both the condensing and evaporator units, split systems with 

the condensing unit and unit cooler physically separated and connected via refrigerant piping, 

and rack systems utilizing unit coolers, which receive refrigerant from a shared loop. The 

proposed test procedure contains separate specific provisions for the standardized testing of each 

refrigeration system type. Later sections provide a general overview of the test procedure for 

refrigeration systems of walk-in coolers and freezers and address some of the technical issues 

pertinent to the proposed test procedure. The following section also addresses issues raised by 

interested parties. 

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1. Overview of the Test Procedure 

In accordance with EPCA, DOE proposes to adopt a test procedure for measuring the 

energy consumption of the refrigeration system of walk-in coolers and freezers. (42 U.S.C. 

6314(a)(9)(B)(i)) DOE is considering adding the following definition for “refrigeration system” 

to 10 CFR part 431, subpart R: “Refrigeration system means the mechanism used to create the 

refrigerated environment in the interior of a walk-in cooler or freezer, consisting of an integrated 

single-package refrigeration unit, or a split system with separate unit cooler and condensing unit 

sections, or a unit cooler that is connected to a central rack system; and including all controls and 

other components integral to the operation of this mechanism.” DOE requests comments on this 

proposed definition. 

In the framework document, DOE examined in detail six test procedures developed either 

by AHRI or ASHRAE that relate to the measurement of energy consumption of refrigeration 

equipment to determine whether they could apply to walk-in refrigeration systems. Although the 

six procedures collectively covered all of the components of the refrigeration systems of walk-in 

coolers and freezers (i.e., the compressor, the condenser, the condensing unit or the unit cooler), 

each of these existing procedures covered only one or some of the components, and none applied 

to the testing of the complete refrigeration system. The rating conditions specified in those 

procedures also are generally not representative of typical conditions found in walk-in 

equipment. 

During the framework public meeting and in a written comment, AHRI informed DOE 

that it has begun developing a standard for the performance rating of walk-in cooler and freezer 

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refrigeration systems. (AHRI, Public Meeting Transcript, No. 15 at p. 50; AHRI, No. 33 at p. 3) 

This standard, AHRI Standard 1250P, “2009 Standard for Performance Rating of Walk in 

Coolers and Freezers,” was published in September of 2009. DOE has reviewed the final, 

published version of AHRI Standard 1250P and proposes to incorporate it by reference into this 

test procedure. 

The test procedure DOE proposes to adopt covers testing of refrigeration systems for 

walk-in coolers and freezers, including unit coolers and condensing units that are sold together as 

a matched system (i.e., paired with each other in a way that optimizes the performance of the 

system), as well as unit coolers and condensing units sold separately, including unit coolers 

connected to compressor racks. The procedure describes the method for measuring the 

refrigeration capacity and the electrical energy consumption for the condensing unit and the unit 

cooler, as well as the off-cycle fan energy and the defrost subsystem under specified test 

conditions. The standard test conditions specify the dry-bulb and wet-bulb temperatures, the 

relative humidity for both the unit cooler and the condensing unit, and require that the system 

must operate under steady-state conditions. The test procedure groups walk-in cooler and freezer 

systems into four categories by distinguishing between indoor and outdoor locations for the 

condensing unit, and between coolers and freezers. The test procedure also specifies calculations 

for the nominal box loads for each of the four categories under typical low- and high-load 

conditions, expressed as a function of the ambient air temperature. (The “nominal box load” 

refers to the refrigeration load imposed on the system by the walk-in envelope. Similar to the 

way in which the envelope was assumed to be paired with a refrigeration system of a given EER 

to provide a means of comparison between different envelopes, DOE assumes that the 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
refrigeration system is paired with an envelope of given heat transfer characteristics. This 

assumption is made for comparison purposes. See section III.B.3.a for further discussion of this 

concept.) For systems in which the condensing unit is located outdoors, the test procedure uses 

bin temperature data and bin hour data to represent the impact of the seasonal variation in outside 

ambient air temperature on energy use. The test procedure computes an annual walk-in 

efficiency factor, or AWEF, for the refrigeration system under a specified thermal load profile 

over a 24-hour operation period. 

2. Test Conditions 

DOE received several comments on test conditions. The Utilities Joint Comment stated 

that most of the potential energy savings can be achieved using floating head pressure and 

variable-speed evaporator fans, both of which are time-varying and weather dependent, and a 

steady-state test may not capture these savings adequately. (Utilities Joint Comment, No. 32 at p. 

4) Manitowoc stated that energy usage can depend on the heat load in the box consisting of 

defrost energy and fan energy, both of which depend on the refrigeration system control strategy. 

(Manitowoc, Public Meeting Transcript, No. 15 at p. 76) NEEA stated that the test conditions 

should reflect variations in the location of the condensing unit, thermal load conditions, and 

outdoor air temperature. (NEEA, No. 18 at p. 3) 

The test procedure DOE proposes specific conditions for both the interior and exterior of 

the walk-in to determine the net refrigeration capacity. The interior conditions of the unit cooler 

are specified as nominal temperature and humidity conditions: 2 °C dry-bulb and less than 50 

percent relative humidity (RH) for coolers, and -23 °C dry-bulb and less than 50 percent RH for 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
freezers. The proposed test procedure would measure both net refrigeration capacity and offcycle fan power at those conditions for the unit cooler. For the condenser, the test procedure 

would specify three different ambient conditions for dry-bulb and wet-bulb temperatures: hot (35 

°C/24 °C), moderate (15 °C /12 °C) and cold (2 °C /1 °C). The purpose of specifying three sets 

of ambient conditions is to capture the variation in capacity under different ambient 

temperatures. 

For two-capacity condensing units, the test procedure would measure the net refrigeration 

capacity under the same set of ambient conditions for the condenser at both the minimum and 

maximum capacity levels. Variable-speed condensing units would also have their refrigeration 

capacities measured at an additional intermediate capacity level. Because the test procedure 

provides for measurement of the compressor power and the fan power at two compressor 

capacity levels for two-speed systems and at three capacity levels for variable-speed systems at 

multiple outside ambient air temperature levels, DOE believes that the proposed test conditions 

reasonably reflect the energy savings that may be achieved through the control strategies referred 

to by interested parties. Also, as mentioned above, the proposed procedure includes a 

measurement of off-cycle fan power, which would account for energy savings due to variablespeed evaporator fans. 

The Joint Comment stated that test procedures should account for partial-load conditions 

as well as maximum loading, and that test methods limited to maximum load conditions at 

steady-state operation are insufficient. (Joint Comment, No. 21 at p. 2) ACEEE also stated that 

the efficiency metric of the refrigeration system should reflect part-load conditions. (ACEEE, 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Public Meeting Transcript, No. 15 at p. 99) In the proposed test procedure, DOE has provided for 

testing of two-capacity and variable-capacity condensing units at the minimum capacity level, 

which would correspond to the appropriate low-load level condition for an appropriately sized 

unit. However, for a single-capacity unit, low-load conditions would lead to a higher frequency 

of equipment cycling because the equipment would be sized for a much larger load; that is, a 

load consistent with worst-case conditions. For single-speed equipment, the proposed test 

procedures do not capture the impact of this cyclic degradation. DOE believes that capturing the 

cyclic degradation is not necessary because, averaged over representative locations in the entire 

country, walk-in coolers may operate for many hours at the full-load condition. For instance, the 

daily pull-down-load in typical walk-in cooler and freezer installations is met over a period of 5 

to 8 hours of full-load operation for a properly sized unit. Consequently, the impact of the cyclic 

degradation is not very significant for the walk-in cooler or freezer refrigeration system. 

Craig noted that the refrigeration systems of walk-in equipment are often oversized to 

account for the worst weather conditions and additional pull-down load. (Craig, Public Meeting 

Transcript, No. 15 at p. 97) Nor-Lake stated that its methodology for determining the 

refrigeration load for the walk-in takes into account the worst conditions over the typical annual 

cycle, as well as product load, pull-down load, the number of door openings, and duration (NorLake, No. 30 at p. 2). The proposed test procedure computes the energy use on the basis of a 

nominal box load, which takes into account product load, infiltration load due to door openings, 

and transmission load through the box walls and roof. DOE believes that the values for the 

nominal box loads adequately reflect typical oversizing values. The proposed annual energy 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
efficiency metric is based on weather conditions that are considered representative of the 

population-weighted average weather conditions of the country as a whole. 

3. Test Methods 

The net refrigeration capacity of the system is determined by one of the following test 

methods: (1) DX Dual Instrumentation measures the enthalpy change and the mass flow rate of 

the refrigerant across the unit cooler using two independent measuring systems; or (2) DX 

Calibrated Box measures the enthalpy change and the mass flow rate of the refrigerant across the 

unit cooler and the heat input to the calibrated box. In the first method, the test unit cooler and 

the matched condensing unit are kept inside separate environmental chambers. In the second 

method, the condensing unit is placed inside the environmental chamber, while the unit cooler is 

kept inside a calibrated box, which is inside a temperature-controlled enclosure. 

DOE believes the test methods are appropriate for walk-ins because they were adapted 

from AHRI Standard 420-2008, “Performance rating of forced-circulation free-delivery unit 

coolers for refrigeration,” and ASHRAE Standard 23, “Methods of Testing for Rating Positive 

Displacement Refrigerant Compressors and Condensing Units,” and have been widely used in 

the refrigeration industry for many years. Furthermore, these test methods were developed and 

approved by the industry and published by the industry trade association as a sufficiently 

adequate means of assessing the net refrigeration capacity of equipment that share many 

functional similarities with walk-ins, such as components, materials, and substances (e.g., the 

refrigerant) that provide the mechanical means of refrigeration.. The test methods DOE is 

proposing today also account for ways in which walk-in refrigeration systems differ from 

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commercial refrigeration equipment; as in their operating conditions, configurations, or patterns 

of use. For example, condensing units of walk-in refrigeration systems may be located outdoors 

and experience a wider range of operating temperatures than commercial refrigeration, which is 

generally located indoors; the walk-in refrigeration test procedure specifies three different 

ambient temperatures at which to test, in order to approximate actual conditions under which the 

system might operate. Furthermore, DOE’s proposed methods improve upon previously 

developed refrigeration test methods by accounting for the energy-saving effects of advanced 

technologies such as variable- speed fans and defrost control strategies. 

4. Measurements and Calculations 

The test procedure DOE proposes to adopt, AHRI Standard 1250P-2009, measures 

certain parameters, including the net refrigeration capacity and the off-cycle fan power for both 

coolers and freezers. The defrost power and thermal energy transferred to the defrost drain water 

are measured for a defrost cycle for freezers only. Separate calculation procedures for singlecapacity, two-capacity, and variable-capacity equipment are included in the test procedure. The 

test procedure determines the annual walk-in energy factor, or AWEF, as the ratio of the annual 

net heat removed from the box, which includes the internal heat gains from non-refrigeration 

components but excludes the heat gains from the refrigeration components in the box, to the 

annual electrical energy consumption. The final metric determined by this procedure is a 

measure of efficiency. However, DOE is required by EPCA to establish “a test procedure to 

measure...energy use.” (42 U.S.C. 6314(a)(9)(B)(i)) In light of this requirement, DOE proposes 

that manufacturers determine both the AWEF and the annual energy consumption of their 

equipment using the test procedure, which will enable the test procedure to be consistent with the 

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requirements of EPCA to develop test procedures that measure the energy consumption of walkin equipment. 

In the AHRI Standard 1250P-2009 calculations, the annual net heat removed from the 

nominal box is represented as a function of ambient temperature surrounding the condenser and 

the measured net refrigeration capacity at the highest test temperature. For refrigeration systems 

consisting of a unit cooler and a dedicated condensing unit, the annual net heat removed from the 

box can be calculated from the system capacity and, for systems located outdoors, the net heat 

removed from the nominal box at a given bin temperature weighted by the number of hours 

corresponding to the bin temperature. The temperature bin data listed in Table D1 of AHRI 

Standard 1250P-2009 has been constructed from the ambient temperatures over a typical 

meteorological year for a specified location, corresponding closely to the use cycle parameters 

prescribed in other DOE standards. For refrigeration systems consisting of a unit cooler 

connected to a remote rack, the net heat removed is a function of the unit cooler capacity at the 

test points specified in AHRI Standard 1250P-2009. 

DOE is considering deriving the expressions for the annual net heat removed from the 

box, that is, the numerator of the equations for energy consumption, by simplifying the equations 

in AHRI Standard 1250P-2009. As an example, the calculation methodology for indoor coolers 

using AHRI Standard 1250P-2009 would be as follows: 

The AWEF, for walk-in cooler systems with dedicated condensing units located indoors, 

is determined by 

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n 

 AWEF  BL(t ) j j E(t )
, Eq. 6 j 1 

where [BL(tj)] is the annual net heat removed from the box over the course of the year, and 

[E(tj)] is the annual energy consumption of the system. Thus, 

n n

E(t j)  BL(t j  ) AWEF . Eq. 7 j1 j1 

AWEF is calculated directly using the test procedure, while BL(tj) is calculated by: 

BL(t j)  0.33L(t j) 	 0.67BLL(t j)
n j . Eq. 8 

For indoor units, tj is assumed to be constant; thus, nj = 8760, the total number of hours in a year. 

BLH and BLL are given by, respectively, 

BLH  0.7  qss (90 F) Eq. 9

and 

BLL  0.1 qss (90 F) , Eq. 10

where qss(90 °F) is the system steady state refrigeration capacity at 90 °F. When terms are 

combined and the expression simplified, the equation for annual energy consumption becomes 

0.30 qss (90 F)8760 Annual Energy Consumption  . Eq. 11 AWEF 

DOE requests comment on using these equations to derive annual energy consumption. 

D. Compliance, Certification, and Enforcement 

Finally, DOE addresses below compliance, certification, and enforcement issues 

involving walk-ins. At this time, DOE is not proposing any specific requirements for this 

equipment. As discussed below, DOE will consider addressing these issues in a separate 

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rulemaking. Any data on which a manufacturer relies for the purposes of certifying compliance 

with any applicable standards that DOE promulgates for this equipment would be derived from 

the test procedure that DOE adopts. The adopted procedure would also be used by DOE during 

enforcement-related testing. 

1. Provisions for Energy Conservation Standards Developed by the Department of Energy 

The purpose of establishing compliance, certification, and enforcement regulations is to 

provide reasonable assurance that manufacturers appropriately test and accurately represent the 

performance characteristics of commercial equipment. DOE recently incorporated the standards 

prescribed by EISA 2007, including those for walk-ins, into 10 CFR Parts 430 and 431. 74 FR 

12074 (March 23, 2009). However, DOE has not yet proposed or issued amended energy 

conservation standards for walk-ins. DOE will consider issuing compliance, certification, and 

enforcement provisions for walk-ins in a future rulemaking. Therefore, today’s notice proposes 

no certification, compliance, or enforcement provisions for energy conservation standards for 

walk-ins. 

2. Provisions for Existing Design Standards Prescribed by Congress 

DOE is responsible for enforcing Federal energy standards, whether those standards were 

developed through a DOE rulemaking pursuant to EPCA or prescribed by Congress. In EISA 

2007, Congress prescribed design standards specifically for walk-ins that took effect on January 

1, 2009. Typically, DOE establishes specific enforcement regulations for each product covered 

by existing standards, which may require manufacturers to file documents such as a compliance 

statement and a certification report. In a compliance statement, the manufacturer certifies its 

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products meet the requirements. In a certification report, the manufacturer provides productspecific information that would enable DOE to determine whether the product meets the 

standard. DOE has already established compliance and certification requirements for other 

products. 

Until DOE finalizes regulations that require compliance statements and certification 

reports for walk-ins, manufacturers will not be required to report data to DOE, but they must still 

meet all prescribed design standards that went into effect on January 1, 2009. If there is a 

question on compliance with design standards, the manufacturer must make a reasonable case 

that the equipment meets those standards. 

To address concerns about the EISA 2007 design requirements for walk-ins, DOE 

maintains a Frequently Asked Questions page on the DOE website at 

http://www1.eere.energy.gov/buildings/appliance_standards/commercial/wicf_faqs.html. 

IV. Regulatory Review 

A. Review Under Executive Order 12866 

The Office of Management and Budget has determined that test procedure rulemakings 

do not constitute “significant regulatory actions” under Executive Order 12866, “Regulatory 

Planning and Review,” 58 FR 51735 (October 4, 1993). Accordingly, this action was not subject 

to review under that Executive Order by the Office of Information and Regulatory Affairs 

(OIRA) of the Office of Management and Budget (OMB). 

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B. Review Under the National Environmental Policy Act 

In this proposed rule, DOE proposes to adopt test procedures and related provisions for 

walk-in equipment. The test procedures would be used initially for the purpose of considering 

the adoption of energy conservation standards for walk-ins, and DOE would require their use 

only if standards were subsequently adopted. The proposed test procedures will not affect the 

quality or distribution of energy and, therefore, will not result in environmental impacts. 

Therefore, DOE determined that this rule falls into a class of actions that are categorically 

excluded from review under the National Environmental Policy Act of 1969 (42 U.S.C. 4321 et 

seq.) and the Department’s implementing regulations at 10 CFR part 1021. More specifically, 

today’s proposed rule is covered by the Categorical Exclusion in paragraph A6 to subpart D, 10 

CFR Part 1021. Accordingly, neither an environmental assessment nor an environmental impact 

statement is required. 

C. Review Under the Regulatory Flexibility Act 

The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires preparation of an initial 

regulatory flexibility analysis (IRFA) for any rule that by law must be proposed for public 

comment, unless the agency certifies that the rule, if promulgated, will not have a significant 

economic impact on a substantial number of small entities. As required by Executive Order 

13272, “Proper Consideration of Small Entities in Agency Rulemaking” (67 FR 53461 (August 

16, 2002)), DOE published procedures and policies on February 19, 2003, to ensure that the 

potential impacts of its rules on small entities are properly considered during the rulemaking 

process. 68 FR 7990. DOE has made its procedures and policies available on the Office of 

General Counsel’s website, http://www.gc.doe.gov. 

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DOE reviewed the test procedures considered in today’s notice of proposed rulemaking 

under the provisions of the Regulatory Flexibility Act and the procedures and policies published 

on February 19, 2003. As discussed in more detail below, DOE found that because the proposed 

test procedures have not previously been required of manufacturers, all manufacturers, including 

small manufacturers, could potentially experience a financial burden associated with new testing 

requirements. While examining this issue, DOE determined that it could not certify that the 

proposed rule, if promulgated, would not have a significant effect on a substantial number of 

small entities. Therefore, DOE has prepared an IRFA for this rulemaking. The IRFA describes 

potential impacts on small businesses associated with walk-in cooler and freezer testing 

requirements. 

DOE has transmitted a copy of this IRFA to the Chief Counsel for Advocacy of the Small 

Business Administration for review. 

1. Reasons for the proposed rule 

Title III of the EPCA sets forth a variety of provisions designed to improve energy 

efficiency. Part B of Title III (42 U.S.C. 6291–6309) provides for the Energy Conservation 

Program for Consumer Products Other Than Automobiles. NECPA (Pub. L. 95-619) amended 

EPCA to add Part C of title III, which established an energy conservation program for certain 

industrial equipment. (42 U.S.C. 6311-6317) (These parts were subsequently redesignated as 

Parts A and A-1, respectively, for editorial reasons.) Section 312 of EISA 2007 further amended 

EPCA by adding certain equipment to this energy conservation program, including walk-in 

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coolers and walk-in freezers (collectively “walk-in equipment” or “walk-ins”), the subject of this 

rulemaking. (42 U.S.C 6311(1), (2), 6313(f) and 6314(a)(9)) The proposed rule would establish a 

test procedure for walk-in coolers and walk-in freezers. 

2. Objectives of, and legal basis for, the proposed rule 

Under EPCA, the overall energy conservation program consists essentially of the 

following parts: testing, labeling, and Federal energy conservation standards. The testing 

requirements for covered equipment consist of test procedures, prescribed under EPCA. The test 

procedures, if adopted, would be used in one of three ways: (1) any data from the use of the test 

procedure, would be used by DOE as a basis for developing standards for walk-in equipment; (2) 

the procedure would be used by DOE when determining equipment compliance with those 

standards; and (3) manufacturers of covered equipment would be required to use the procedure 

as the basis for establishing that their equipment complies with the relevant energy conservation 

standards promulgated pursuant to EPCA and when making representations regarding equipment 

efficiency. 

Section 343 of EPCA (42 U.S.C. 6314) sets forth generally applicable criteria and 

procedures for DOE’s adoption and amendment of test procedures for covered equipment. That 

provision requires that the test procedures promulgated by DOE be reasonably designed to 

produce test results which reflect energy efficiency, energy use, and estimated operating costs of 

the covered equipment during a representative average use cycle. It also requires that the test 

procedure not be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2)) Further information 

concerning the background of this rulemaking is provided in Section I of this preamble. 

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3. Description and estimated number of small entities regulated 

Small businesses, as defined by the Small Business Administration (SBA) for the walk-in 

cooler and freezer manufacturing industry, are manufacturing enterprises with 750 employees or 

fewer. DOE used the small business size standards published on January 31, 1996, as amended, 

by the SBA to determine whether any small entities would be required to comply with the rule. 

61 FR 3286; see also 65 FR 30836, 30850 (May 15, 2000), as amended at 65 FR 53533, 53545 

(September 5, 2000). The size standards are codified at 13 CFR Part 121. The standards are 

listed by North American Industry Classification System (NAICS) code and industry description 

and are available at 

http://www.sba.gov/idc/groups/public/documents/sba_homepage/serv_sstd_tablepdf.pdf. Walkin cooler and freezer equipment manufacturing is classified under NAICS 333415, AirConditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration 

Equipment Manufacturing. 

DOE reviewed AHRI’s listing of commercial refrigeration equipment manufacturer 

members and surveyed the industry to develop a list of domestic manufacturers. DOE also asked 

stakeholders and AHRI representatives within the industry if they were aware of any other small 

business manufacturers. DOE then examined publicly available data, including regulatory 

databases such as state databases and the National Sanitation Foundation (NSF) Section 7 

database. DOE identified at least 37 small manufacturers of walk-in cooler and freezer 

envelopes, and at least 5 small manufacturers of walk-in cooler and freezer refrigeration systems. 

However, some manufacturers that DOE interviewed indicated that there could be many more 

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small business manufacturers than were publicly listed. Such unlisted manufacturers could be 

very small (<50 employees) and serve only a local market. They also may not submit any 

information to state or national regulators such as NSF. Therefore, DOE believes there may be 

more affected small entities than it estimated and seeks comment on the number of small entities 

that may be impacted by the test procedure. 

4. Description and estimate of compliance requirements 

Potential impacts of the proposed test procedures on manufacturers, including small 

businesses, come from impacts associated with the cost of testing. In this test procedure NOPR, 

DOE proposes measures to reduce the financial burden of testing on all manufacturers, including 

small business manufacturers. First, where the procedure gives manufacturers options in terms of 

materials, equipment, or methodology to be used in performing the test, DOE proposes to allow 

manufacturers to use the lowest-cost option, where possible. For instance, ASTM E741-06 

allows manufacturers to use any of about 12 tracer gases. DOE specifies a tracer gas to ensure 

that all manufacturers report at the same accuracy, but specifies the use of carbon dioxide, which 

would be the lowest cost option. Second, DOE proposes to reduce the total number of tests 

manufacturers would have to perform by allowing them to group similar equipment into a single 

family, or basic model, and only requiring them to test one unit of each basic model. (See section 

III.A.1for a more detailed discussion of the basic model proposal.) 

The proposed test procedure for envelopes would require manufacturers to perform 

testing in accordance with two industry test standards: ASTM C1303-08, “Standard Test Method 

of Predicting Long Term Thermal Resistance of Closed-Cell Foam Insulation,” and ASTM 

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E741-06, “Standard Test Method for Determining Air Change in a Single Zone by Means of a 

Tracer Gas Dilution.” DOE spoke with industry experts to determine the approximate cost of 

each test and determined that a test using ASTM C1303-08 costs between approximately $5,000 

and $10,000, and a test using ASTM E741-06 costs between $1,000 and $5,000. A typical 

manufacturer would have approximately 8 basic models, so the total cost of compliance would 

be approximately $84,000. 

The proposed test procedure for refrigeration systems would require manufacturers to 

perform testing in accordance with a single industry test standard: AHRI Standard 1250P-2009, 

“2009 Standard for Performance Rating of Walk-In Coolers and Freezers.” Because this test was 

recently developed by the industry and has not yet been widely used to test refrigeration systems, 

DOE could not determine how much the test currently costs. However, DOE researched the cost 

of other, similar standards and subsequently estimated that a test using AHRI Standard 1250P2009 would likely cost approximately $5,000. A typical refrigeration manufacturer could have 

approximately 50 basic models, making the total cost of compliance approximately $250,000. 

Because the cost of running each test is the same for all manufacturers, and because DOE 

has proposed measures to reduce burden on all manufacturers, DOE believes that all 

manufacturers would incur comparable costs as a result of the proposed test procedures. 

However, DOE does not expect that small manufacturers would have fewer basic models than 

large manufacturers, because the equipment is highly customized throughout the industry. A 

small manufacturer could have the same total cost of testing as a large manufacturer, but this cost 

would be a higher percentage of a small manufacturer’s annual revenues. Thus, DOE cannot 

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certify that the differential impact associated with walk-in cooler and freezer test procedures on 

small businesses would not be significant. 

5. Duplication, overlap, and conflict with other rules and regulations 

DOE is not aware of any rules or regulations that duplicate, overlap, or conflict with the 

rule being considered today. 

6. Significant alternatives to the rule 

DOE considered a number of alternatives to the proposed test procedure, including test 

procedures that incorporate industry test standards other than the three proposed standards, 

ASTM C1303-08, ASTM E741-06, and AHRI Standard 1250P-2009, described above. 

Instead of requiring ASTM C1303-08 for testing the long-term thermal properties of insulation, 

DOE could require only ASTM C518-04, “Standard Test Method for Steady-State Thermal 

Transmission Properties by Means of the Heat Flow Meter Apparatus,” which tests the thermal 

properties of insulation at a certain point in time (i.e., the point of manufacture). (Because ASTM 

C1303-08 incorporates ASTM C518-04, requiring ASTM C1303-08 is consistent with the 

statutory requirement for basing measurement of the thermal conductivity of the insulation on 

ASTM C518-04.) (42 U.S.C. 6314(a)(9)(A)) A test of ASTM C518-04 alone costs 

approximately $500-$1,000. However, DOE is considering ASTM C1303 for other reasons; 

namely, the concern that ASTM C518-04 alone does not capture the performance characteristics 

of a walk-in over the period of its use, because it does not account for significant changes in the 

thermal properties of insulation over time. For more discussion on this issue, see Section 

III.B.2.a. 

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DOE also considered ASTM E1827-96(2007), “Standard Test Methods for Determining 

Airtightness of Buildings Using an Orifice Blower Door,” instead of ASTM E741-06, for testing 

infiltration. ASTM E1827-96(2007) costs about $300-$500 for a single test. However, DOE 

believes that ASTM E1827-96(2007) is not appropriate for walk-ins because it is conducted by 

placing test equipment in the door, and thus does not account for in infiltration through the door, 

which is a major component of infiltration in walk-ins. In addition, it is not intended for testing 

envelope systems, such as a walk-in, that have a large temperature difference between the 

internal and external air. Therefore, to complete a blower-door test, the walk-in would not be 

able to be tested at or close to operational temperatures, resulting in a test that does not 

accurately reflect its performance. For more discussion on this issue, see Section III.B.2.b. 

In the framework document, DOE considered adapting an existing test procedure for 

commercial refrigeration equipment, such as ARI Standard 1200-2006, “Performance Rating of 

Commercial Refrigerated Display Merchandisers and Storage Cabinets,” as an alternative to 

AHRI Standard 1250P-2009. The two tests are based on a similar methodology for rating 

refrigeration equipment in general, but ARI Standard 1200-2006 requires testing at only one set 

of ambient conditions, whereas AHRI Standard 1250P-2009 requires testing at 3 sets of ambient 

conditions for refrigeration systems with the condensing units located outdoors. The additional 

time required to test the system at 3 sets of conditions would incur additional cost and could 

make AHRI Standard 1250P-2009 more burdensome than ARI Standard 1200-2006. However, 

DOE believes that AHRI Standard 1250P-2009 is more appropriate for testing walk-ins than ARI 

Standard 1200-2006. A test procedure based on ARI Standard 1200-2006 would require the 

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entire walk-in to be tested as a whole, but manufacturers might not have a large enough test 

facility to make the measurements necessary for the ARI 1200-2006 test procedure in a 

controlled environment. Also, the refrigeration system is often manufactured separately from the 

insulated envelope. In this case, whoever assembled the two components would bear the burden 

of conducting ARI 1200-2006; this party might not be the manufacturer of the refrigeration 

system. In contrast, AHRI 1250P-2009 tests only the refrigeration system. It does not require a 

larger test chamber than other, similar tests, and can be conducted by the manufacturer of the 

refrigeration system. Furthermore, because AHRI 1250P-2009 requires the system to be tested at 

3 ambient temperatures, it captures energy savings from features (for example, floating head 

pressure) that allow the system to use less energy at lower ambient temperatures. For more 

discussion on this issue, see Section III.A.2. 

DOE requests comment on the impacts to small business manufacturers for these and 

any other possible alternatives to the proposed rule. DOE will consider any comments received 

regarding impacts to small business manufacturers for all the alternatives identified. 

D. Review Under the Paperwork Reduction Act 

Today’s proposed rule contains no record-keeping requirements. Therefore, today’s 

notice of proposed rulemaking would not impose any new reporting requirements requiring 

clearance by OMB under the Paperwork Reduction Act, 44 U.S.C.3501 et seq. The Department 

recognizes, however, that if it adopts standards for walk-in coolers and walk-in freezers, once the 

standards become operative, manufacturers may become subject to record-keeping requirements 

associated with compliance with the standards. Therefore, the Department will comply with the 

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record-keeping requirements of the Paperwork Reduction Act if and when energy conservation 

standards are adopted. 

E. Review Under the Unfunded Mandates Reform Act of 1995 

Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104–4) (UMRA) 

requires each Federal agency to assess the effects of Federal regulatory actions on State, local, 

and tribal governments and the private sector. With respect to a proposed regulatory action that 

may result in the expenditure by State, local and tribal governments, in the aggregate, or by the 

private sector of $100 million or more (adjusted annually for inflation), section 202 of UMRA 

requires a Federal agency to publish estimates of the resulting costs, benefits, and other effects 

on the national economy. (2 U.S.C. 1532(a), (b)) UMRA also requires a Federal agency to 

develop an effective process to permit timely input by elected officers of State, local, and tribal 

governments on a proposed “significant intergovernmental mandate,” and requires an agency 

plan for giving notice and opportunity for timely input to potentially affected small governments 

before establishing any requirements that might significantly or uniquely affect small 

governments. On March 18, 1997, DOE published a statement of policy on its process for 

intergovernmental consultation under UMRA (62 FR12820) (also available at www.gc.doe.gov). 

The proposed rule published today does not provide for any Federal mandate likely to result in 

an aggregate expenditure of $100 million or more. Therefore, the UMRA does not require a cost 

benefit analysis of today’s proposal. 

F. Review Under the Treasury and General Government Appropriations Act, 1999 

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Section 654 of the Treasury and General Government Appropriations Act, 1999 (Pub. L. 

105–277) requires Federal agencies to issue a Family Policymaking Assessment for any rule that 

may affect family well-being. This proposed rule would not have any impact on the autonomy or 

integrity of the family as an institution. Accordingly, DOE has concluded that it is not necessary 

to prepare a Family Policymaking Assessment. 

G. Review Under Executive Order 13132 

Executive Order 13132, “Federalism,” 64 FR 43255 (August 4, 1999) imposes certain 

requirements on agencies formulating and implementing policies or regulations that preempt 

State law or that have federalism implications. The Executive Order requires agencies to 

examine the constitutional and statutory authority supporting any action that would limit the 

policymaking discretion of the States and carefully assess the necessity for such actions. The 

Executive Order also requires agencies to have an accountable process to ensure meaningful and 

timely input by State and local officials in the development of regulatory policies that have 

federalism implications. On March 14, 2000, DOE published a statement of policy describing the 

intergovernmental consultation process it will follow in the development of such regulations (65 

FR 13735). DOE has examined today’s proposed rule and has determined that it does not 

preempt State law and does not have a substantial direct effect on the States, on the relationship 

between the national government and the States, or on the distribution of power and 

responsibilities among the various levels of government. EPCA governs and prescribes Federal 

preemption of State regulations as to energy conservation for the products that are the subject of 

today’s proposed rule. States can petition DOE for exemption from such preemption to the 

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extent, and based on criteria, set forth in EPCA. (42 U.S.C. 6297) No further action is required 

by Executive Order 13132. 

H. Review Under Executive Order 12988 

With respect to the review of existing regulations and the promulgation of new 

regulations, section 3(a) of Executive Order 12988, “Civil Justice Reform” (61 FR 4729, 

February 7, 1996), imposes on Federal agencies the general duty to adhere to the following 

requirements: (1) eliminate drafting errors and ambiguity, (2) write regulations to minimize 

litigation, and (3) provide a clear legal standard for affected conduct rather than a general 

standard and promote simplification and burden reduction. Section 3(b) of Executive Order 

12988 specifically requires that Executive agencies make every reasonable effort to ensure that 

the regulation (1) clearly specifies the preemptive effect, if any; (2) clearly specifies any effect 

on existing Federal law or regulation; (3) provides a clear legal standard for affected conduct 

while promoting simplification and burden reduction; (4) specifies the retroactive effect, if any; 

(5) adequately defines key terms; and (6) addresses other important issues affecting clarity and 

general draftsmanship under any guidelines issued by the Attorney General. Section 3(c) of 

Executive Order 12988 requires Executive agencies to review regulations in light of applicable 

standards in section 3(a) and section 3(b) to determine whether they are met or it is unreasonable 

to meet one or more of them. DOE has completed the required review and determined that, to the 

extent permitted by law, this proposed rule meets the relevant standards of Executive Order 

12988. 

I. Review Under the Treasury and General Government Appropriations Act, 2001 

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The Treasury and General Government Appropriations Act, 2001 (44 U.S.C. 3516, note) 

provides for agencies to review most disseminations of information to the public under 

guidelines established by each agency pursuant to general guidelines issued by OMB. OMB’s 

guidelines were published at 67 FR 8452 (February 22, 2002), and DOE’s guidelines were 

published at 67 FR 62446 (October 7, 2002). DOE has reviewed today’s notice under the OMB 

and DOE guidelines and has concluded that it is consistent with applicable policies in those 

guidelines. 

J. Review Under Executive Order 13211 

Executive Order 13211, “Actions Concerning Regulations That Significantly Affect 

Energy Supply, Distribution, or Use,” 66 FR 28355 (May 22, 2001) requires Federal agencies to 

prepare and submit to the Office of Information and Regulatory Affairs (OIRA), Office of 

Management and Budget, a Statement of Energy Effects for any proposed significant energy 

action. A “significant energy action” is defined as any action by an agency that promulgated or is 

expected to lead to promulgation of a final rule, and that (1) is a significant regulatory action 

under Executive Order 12866, or any successor order; and (2) is likely to have a significant 

adverse effect on the supply, distribution, or use of energy; or (3) is designated by the 

Administrator of OIRA as a significant energy action. For any proposed significant energy 

action, the agency must give a detailed statement of any adverse effects on energy supply, 

distribution, or use should the proposal be implemented, and of reasonable alternatives to the 

action and their expected benefits on energy supply, distribution, and use. Today’s regulatory 

action is not a significant regulatory action under Executive Order 12866. Moreover, it would not 

have a significant adverse effect on the supply, distribution, or use of energy. The Administrator 

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of OIRA also did not designate today’s action as a significant energy action. Therefore, it is not a 

significant energy action, and DOE has not prepared a Statement of Energy Effects. 

K. Review Under Executive Order 12630 

DOE has determined pursuant to Executive Order 12630, “Governmental Actions and 

Interference with Constitutionally Protected Property Rights,” 53 FR 8859 (March 18, 1988) that 

this proposed rule would not result in any takings which might require compensation under the 

Fifth Amendment to the United States Constitution. 

L. Review Under Section 32 of the Federal Energy Administration (FEA) Act of 1974 

Under section 301 of the Department of Energy Organization Act (Pub. L. 95–91), DOE 

must comply with section 32 of the Federal Energy Administration Act of 1974, as amended by 

the Federal Energy Administration Authorization Act of 1977. (15 U.S.C. 788) Section 32 

provides in part that, where a proposed rule contains or involves use of commercial standards, 

the rulemaking must inform the public of the use and background of such standards. The rule 

proposed in this notice incorporates testing methods contained in the following commercial 

standards: ASTM C1303-08, “Standard Test Method of Predicting Long Term Thermal 

Resistance of Closed-Cell Foam Insulation;” ASTM E741-06, “Standard Test Method for 

Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution;” and AHRI 

Standard 1250P, “2009 Standard for Performance Rating of Walk in Coolers and Freezers.” The 

Department has evaluated these standards and is unable to conclude whether they fully comply 

with the requirements of section 32(b) of the Federal Energy Administration Act, i.e., whether 

they were developed in a manner that fully provides for public participation, comment, and 

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review. As required by section 32(c) of the Federal Energy Administration Act, of 1974, as 

amended, DOE will consult with the Attorney General and the Chairman of the Federal Trade 

Commission before prescribing a final rule concerning the impact on competition of requiring 

manufacturers to use the methods contained in these standards to test walk-in equipment. 

V. Public Participation 

A. Attendance at Public Meeting 

The time, date, and location of the public meeting are provided in the DATES and 

ADDRESSES sections at the beginning of this document. Anyone who wants to attend the 

public meeting must notify Ms. Brenda Edwards at (202) 586-2945. As explained in the 

ADDRESSES section, foreign nationals visiting DOE headquarters are subject to advance 

security screening procedures. 

B. Procedure for Submitting Requests to Speak 

Any person who has an interest in the topics addressed in this notice, or who is a 

representative of a group or class of persons that has an interest in these issues, may request an 

opportunity to make an oral presentation at the public meeting. Such persons may hand-deliver 

requests to speak to the address shown in the ADDRESSES section at the beginning of this 

notice between 9:00 a.m. and 4:00 p.m., Monday through Friday, except Federal holidays. 

Requests may also be sent by mail or email to: Ms. Brenda Edwards, U.S. Department of 

Energy, Building Technologies Program, Mailstop EE-2J, 1000 Independence Avenue, S.W., 

Washington, DC 20585-0121, or Brenda.Edwards@ee.doe.gov. Persons who wish to speak 

should include in their request a computer diskette or CD in WordPerfect, Microsoft Word, PDF, 

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or text (ASCII) file format that briefly describes the nature of their interest in this rulemaking 

and the topics they wish to discuss. Such persons should also provide a daytime telephone 

number where they can be reached. 

DOE requests that those persons who are scheduled to speak submit a copy of their 

statements at least one week prior to the public meeting. DOE may permit any person who 

cannot supply an advance copy of this statement to participate, if that person has made 

alternative arrangements with the Building Technologies Program in advance. When necessary, 

the request to give an oral presentation should ask for such alternative arrangements. 

C. Conduct of Public Meeting 

DOE will designate a DOE official to preside at the public meeting and may also employ 

a professional facilitator to aid discussion. The public meeting will be conducted in an informal, 

conference style. The meeting will not be a judicial or evidentiary public hearing, but DOE will 

conduct it in accordance with section 336 of EPCA (42 U.S.C. 6306). Discussion of proprietary 

information, costs or prices, market share, or other commercial matters regulated by U.S. antitrust laws is not permitted. 

DOE reserves the right to schedule the order of presentations and to establish the 

procedures governing the conduct of the public meeting. A court reporter will record the 

proceedings and prepare a transcript. 

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At the public meeting, DOE will present summaries of comments received before the 

public meeting, allow time for presentations by participants, and encourage all interested parties 

to share their views on issues affecting this rulemaking. Each participant may present a prepared 

general statement (within time limits determined by DOE) before the discussion of specific 

topics. Other participants may comment briefly on any general statements. At the end of the 

prepared statements on each specific topic, participants may clarify their statements briefly and 

comment on statements made by others. Participants should be prepared to answer questions 

from DOE and other participants. DOE representatives may also ask questions about other 

matters relevant to this rulemaking. The official conducting the public meeting will accept 

additional comments or questions from those attending, as time permits. The presiding official 

will announce any further procedural rules or modification of procedures needed for the proper 

conduct of the public meeting. 

DOE will make the entire record of this proposed rulemaking, including the transcript 

from the public meeting, available for inspection at the U.S. Department of Energy, 6th Floor, 

950 L'Enfant Plaza, SW., Washington, DC 20024, (202) 586– 2945, between 9:00 a.m. and 4:00 

p.m., Monday through Friday, except Federal holidays. Anyone may purchase a copy of the 

transcript from the transcribing reporter. 

D. Submission of Comments 

DOE will accept comments, data, and information regarding the proposed rule no later 

than the date provided at the beginning of this notice. Comments, data, and information 

submitted to DOE’s e-mail address for this rulemaking should be provided in WordPerfect, 

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Microsoft Word, PDF, or text (ASCII) file format. Interested parties should avoid the use of 

special characters or any form of encryption, and wherever possible, comments should include 

the electronic signature of the author. Absent an electronic signature, comments submitted 

electronically must be followed and authenticated by submitting a signed original paper 

document to the address provided at the beginning of this notice. Comments, data, and 

information submitted to DOE via mail or hand delivery/courier should include one signed 

original paper copy. No telefacsimiles (faxes) will be accepted. 

According to 10 CFR 1004.11, any person submitting information that he or she believes 

to be confidential and exempt by law from public disclosure should submit two copies: one copy 

of the document including all the information believed to be confidential, and one copy of the 

document with the information believed to be confidential deleted. DOE will make its own 

determination as to the confidential status of the information and treat it according to its 

determination. 

Factors of interest to DOE when evaluating requests to treat submitted information as 

confidential include (1) a description of the items, (2) whether and why such items are 

customarily treated as confidential within the industry, (3) whether the information is generally 

known by or available from other sources, (4) whether the information has previously been made 

available to others without obligation concerning its confidentiality, (5) an explanation of the 

competitive injury to the submitting person which would result from public disclosure, (6) a date 

upon which such information might lose its confidential nature due to the passage of time, and 

(7) why disclosure of the information would be contrary to the public interest. 

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E. Issues on Which DOE Seeks Comment 

DOE is particularly interested in receiving comments on the following issues: 

1. Test Procedure Improvements 

DOE requests comments on improvements in the test procedures that it should consider. 

In submitting comments, interested parties should state the nature of the recommended 

modification and an explanation of how it improves upon the test procedure proposed in this 

NOPR. See section II for details. 

2. Basic Model 

Because walk-in equipment tends to be highly customized, DOE is considering allowing 

manufacturers to group similar walk-in equipment under a single “basic model” and only 

subjecting one unit of each basic model to testing. DOE will use the term “basic model” to 

represent a single family of walk-in equipment, consisting of walk-in equipment or models of 

equipment that do not have any differentiating electrical, physical, or functional features that 

significantly affect energy consumption characteristics. DOE requests comments on the proposed 

basic model approach. See section III.A.1 for details. 

3. Separate Envelope and Refrigeration Tests 

For any walk-in, two different manufacturers may make the two main components: the 

envelope, or insulated box, and the refrigeration system. In this notice, DOE proposes separate 

test procedures for the envelope and the refrigeration system. The envelope manufacturer would 

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be responsible for testing the envelope according to the envelope test procedure, and the 

refrigeration system manufacturer would be responsible for testing the refrigeration system 

according to the refrigeration system test procedure. The purpose of this provision is to 

accurately reflect the structure of the walk-in market and assign testing responsibilities to the 

equipment manufacturers. DOE requests comments on the proposed approach to develop 

separate test procedures. See section III.A.4 for details. 

4. Definition of Envelope 

DOE requests comments on the following definition of “envelope:” “(1) a piece of 

equipment that is the portion of a walk-in cooler or walk-in freezer that isolates the interior, 

refrigerated environment from the ambient, external environment; and (2) all energy-consuming 

components of the walk-in cooler or walk-in freezer that are not part of its refrigeration system.” 

See section III.B.1 for details. 

5. Effect of Impermeable Skins on Long-Term R-Value 

DOE received many comments on the framework document regarding long-term Rvalue. After researching the issue, DOE determined that the R-value of insulating foams 

diminish after manufacture at rates that vary by material type and environmental conditions. 

Diffusion of gases and moisture infiltration are the key mechanisms of R-value decline. Many 

manufacturers seek to prevent or delay diffusion and moisture infiltration by sealing the foam in 

a “skin,” typically a metal material. DOE received comments suggesting that these skins can be 

made fully impermeable while other comments argued that full impermeability cannot be 

achieved due to imperfect sealing at panel joints, imperfect adherence of foam to metal during 

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manufacture, deliberate punctures for fixtures and shelving, and/or inadvertent punctures that 

typically occur in the field. DOE requests feedback on this issue, including the submission of test 

results on the impact of impermeable skins on long-term R-value. Specifically, DOE requests 

that interested parties submit or identify any peer-reviewed, published data pertaining to the 

efficacy of skins in preventing or delaying R-value decline. See section III.B.2.a for details. 

6. Measuring Long-Term R-Value Using American Society for Testing and Materials 

(ASTM) C1303-08 

DOE proposes accounting for R-value decline due to diffusion of gases by requiring 

manufacturers to condition their foam prior to testing. DOE proposes requiring manufacturers to 

condition foam using ASTM C1303-08, which conditions foam using an accelerated aging 

method prior to testing its R-value. Because ASTM C1303-08 uses ASTM C518-2004, using 

ASTM C1303-08 would be consistent with EPCA. (42 U.S.C. 6314(a)(9)(A)(ii)) DOE requests 

feedback on the proposal to require conditioning and testing foam using ASTM C1303-08. DOE 

recognizes that ASTM C1303-08 is designed for unfaced and permeably faced foams rather than 

the impermeably faced foams typical of walk-ins. DOE requests feedback on the use of ASTM 

C1303-08 for foams that will be impermeably faced. 

DOE is considering several exceptions and clarifications to ASTM C1303-08 to satisfy 

requirements of EPCA and to make the test procedure more applicable to walk-ins. DOE 

requests feedback on the number of samples and sample thicknesses, the use of interpolation of 

results for foam thicknesses within the specified ±0.5 inch range, and the use of the core stack Rvalue out of a sample size of three stacks for the purpose of calculating walk-in energy use. 

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Lastly, ASTM C1303-08 cannot be used for non-foam materials, but DOE is not aware of 

any non-foam materials currently being used as insulation in walk-in coolers or freezers. DOE 

requests comment on whether non-foam technologies, such as vacuum insulated panels or 

aerogels, are likely to be commercially available for walk-ins within the next 5 years. See section 

III.B.2.a for details. 

7. Infiltration 

Air infiltration causes a substantial amount of heat gain through the envelope. After 

evaluating several methods of testing and measuring the air infiltration, DOE proposes requiring 

ASTM E741-06, also referred to as the gas tracer method, as the test procedure for measuring 

steady-state infiltration and the effectiveness of infiltration reduction devices (for air infiltration 

unrelated to door opening events). Because door opening also contributes to infiltration, DOE 

proposes accounting for this infiltration pathway. DOE does not, however, propose to require 

manufacturers to individually measure the infiltration from door opening events, due to the 

complexity of this type of testing and the availability of accurate analytical models, which would 

make a test procedure very difficult to implement. DOE proposes using analytical methods based 

on ASHRAE fundamentals as well as assumed door-opening frequency and duration and the 

measured infiltration barrier effectiveness to calculate the air infiltration associated with each 

door-opening event. DOE requests comments on the proposed test method for steady-state 

infiltration. DOE requests input and feedback on the calculations and assumptions proposed for 

determining infiltration from door-opening events. See section III.B.2.b for details on the 

proposed analytical methods. 

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8. Nominal Coefficient of Performance of Refrigeration 

In developing a test procedure for the envelope alone, without a refrigeration system, 

DOE had to determine the energy consumption associated with heat gain through the envelope 

due to conduction and infiltration. DOE proposes to assume a nominal EER for the refrigeration 

system to convert the heat gain through the box into a measure of the energy consumption of a 

theoretical refrigeration system that would be removing this heat from the box. For comparison 

purposes, DOE recommends that the EER be 12.4 Btu per watt hour (Btu/Wh) for coolers and 

6.3 Btu/Wh for freezers because these are typical EER values. DOE requests comments on this 

proposal and on the assumed value for the EER. See section III.B.3.a for details. 

9. Measuring the U-Value of glass 

Because conduction through glass components can be a significant source of heat transfer 

through walk-in envelopes, DOE seeks to order to account for improvements in glass 

performance in the test procedure. DOE proposes two options for manufacturers: (1) If 

manufacturers of glass doors used in walk-ins participate in the NFRC rating program, the 

performance of the door shall be simply read from its label and used for calculations in this test 

procedure. If glass door manufacturers do not participate in the NFRC rating program, then (2) 

DOE proposes to require manufacturers to use the LBNL’s publicly available Window 5.2 

software package to calculate glass door performance. DOE seeks comment on the availability of 

performance data on glass products used in walk-in applications, glass component 

manufacturers’ participation in third party certification programs such as NFRC, and the 

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proposed method for predicting the thermal performance of glass components using Window 5.2. 

See section III.B.3.b for more information. 

10. Floor R-Value 

EPCA does not require walk-in cooler floors to meet a specific R-value. In many 

instances, walk-in coolers are shipped without additional insulating floors and are simply placed 

on top of an existing surface, such as a concrete slab. Since concrete is the floor surface most 

commonly used with floorless walk-in coolers DOE is considering using the R-value of 6-inch 

concrete to calculate energy lost through these floors. DOE proposes using an R-value of 0.6 ft2

-

° F-hr/Btu for 6-inch concrete. Since walk-in freezers are required to have a floor insulation of 

R-28, DOE will assume this R-value for purposes of calculating the energy loss through walk-in 

freezer floors if the manufacturer does not provide any additional insulating surface. DOE 

requests comments on these assumptions. See section III.B.3.b for details. 

11. Electrical Duty Cycle 

As part of the envelope test procedure, DOE recommends calculating the electricity 

consumption of lights, sensors, and other miscellaneous electrical devices not considered part of 

the refrigeration equipment using name-plate rating and an assumed daily operation. DOE 

incorporates assumed duty cycles of lights, anti-sweat heaters, and other devices based on 

whether they are controlled by a preset control system. While these assumptions may not reflect 

the actual behaviorally related energy consumption, they will provide a means for comparison. 

DOE requests comments on whether the duty cycle assumptions are appropriate. See section 

III.B.3.d for details. 

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12. Normalization Factor 

For the envelope test procedure, DOE proposes to normalize the energy consumption by 

a certain factor related to the size of the walk-in so that manufacturers of larger walk-ins and 

walk-ins with glass doors are not unfairly penalized. DOE believes that the surface area of the 

envelope is an appropriate normalization factor, because surface area is the key geometric 

characteristic related to both conduction and infiltration and is particularly important as the ratio 

of glass door area to wall area increases. DOE requests comments on the proposal to normalize 

the energy consumption by the surface area of the walk-in. See section III.B.3.e for details. 

13. Daily Energy Consumption Coefficients 

In order to compare envelopes that are similar enough to be included in the same basic 

model but are not identical, the test procedure allows for calculating Daily Energy Consumption 

Coefficients, or DECCs, using test results from a particular envelope within a basic model, and 

then applying these DECCs to other envelopes within a basic model to calculate the energy 

consumption of the other units. DECCs are essentially scaling factors that allow a manufacturer 

to change certain parameters of an envelope and calculate the corresponding change in energy 

consumption. DOE believes that this approach would reduce the testing burden on manufacturers 

because it would not require manufacturers to test every unit produced with slight variations due 

to customer specification. DOE requests comment on this rating methodology. For formulas and 

more information, see section III.B.3.f. 

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14. Definition of Refrigeration System 

DOE requests comments on the following definition of “refrigeration system:” “the 

mechanism used to create the refrigerated environment in the interior of a walk-in cooler or 

freezer, consisting of an integrated single-package refrigeration unit, or a split system with 

separate unit cooler and condensing unit sections, or a unit cooler that is connected to a central 

rack system; and including all controls and other components integral to the operation of this 

mechanism.” See section III.C.1 for details. 

15. Measurements and Calculations of Energy Use of Refrigeration Systems 

The test procedure DOE proposes to adopt, AHRI Standard 1250P-2009, determines the 

annual walk-in energy factor, or AWEF, which is a measure of the efficiency of a walk-in’s 

refrigeration system. However, DOE is required by EPCA to establish “a test procedure to 

measure...energy use.” (42 U.S.C. 6314(a)(9)(B)(i)) In light of this requirement, DOE proposes 

that manufacturers determine both the AWEF and the annual energy consumption of their 

equipment using the test procedure, which will enable the test procedure to be consistent with the 

requirements of EPCA to develop test procedures that measure the energy consumption of walkin equipment. DOE is considering satisfying the statutory requirement by deriving the energy 

consumption of the walk-in refrigeration system from data obtained when the test procedure is 

performed. DOE’s derivation process, and further information, can be found in section III.C.4. 

16. Impacts on Small Businesses 

The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires preparation of an initial 

regulatory flexibility analysis (IRFA) for any rule that by law must be proposed for public 

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comment, unless the agency certifies that the rule, if promulgated, will not have a significant 

economic impact on a substantial number of small entities. Upon examination of this NOPR, 

DOE could not certify that the rule, if promulgated, would not have a significant economic 

impact on a substantial number of small entities; therefore, DOE prepared an IRFA for this rule. 

DOE requests comment on the number of small businesses affected by the proposed rule, and 

seeks comment on impacts to small business manufacturers for any possible alternatives to the 

proposed rule. More information, along with the text of the IRFA, can be found in section IV.C. 

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_________________________________ 

VI. Approval of the Office of the Secretary 

The Secretary of Energy has approved publication of this proposed rule. 

List of Subjects in 10 CFR Part 431 

Administrative practice and procedure, Confidential business information, Energy 

conservation, Reporting and recordkeeping requirements. 

Issued in Washington, DC, on December 14, 2009. 

Cathy Zoi 

Assistant Secretary 

Energy Efficiency and Renewable Energy 

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For the reasons stated in the preamble, DOE proposes to amend part 431 of chapter II of title 10, 

of the Code of Federal Regulations, to read as set forth below. 

PART 431—ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 

INDUSTRIAL EQUIPMENT 

1. The authority citation for part 431 continues to read as follows: 

Authority: 42 U.S.C. 6291-6317. 

2. Section 431.302 is amended by adding, in alphabetical order, definitions for “Basic 

model,” “Envelope,” “Refrigeration system,” and “Walk-in equipment” to read as 

follows: 

§ 431.302 Definitions concerning walk-in coolers and walk-in freezers. 

Basic Model means all units of a given type of walk-in equipment manufactured by a 

single manufacturer, and— 

(1) With respect to envelopes, which do not have any differing construction methods, 

materials, components, or other characteristics that significantly affect the energy consumption 

characteristics. 

(2) With respect to refrigeration systems, which have the same primary energy source and 

which do not have any differing electrical, physical, or functional characteristics that 

significantly affect energy consumption. 

Envelope means (1) the portion of a walk-in cooler or walk-in freezer that isolates the 

interior, refrigerated environment from the ambient, external environment; and (2) all energyconsuming components of the walk-in cooler or walk-in freezer that are not part of its 

refrigeration system. 

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Refrigeration system means the mechanism used to create the refrigerated environment in 

the interior of a walk-in cooler or freezer, consisting of an integrated single-package refrigeration 

unit, or a split system with separate unit cooler and condensing unit sections, or a unit cooler that 

is connected to a central rack system; and including all controls and other components integral to 

the operation of this mechanism. 

* * * * * 

 Walk-in equipment means either the envelope or the refrigeration system of a walk-in 

cooler or freezer. 

3. Section 431.303 is amended by adding new paragraphs (b)(2), (b)(3), and (c) to read as 

follows: 

§ 431.303 Materials incorporated by reference. 

* * * * * 

(b) * * * 

(1) * * * 

(2) ASTM C1303-08, Standard Test Method of Predicting Long Term Thermal Resistance of 

Closed-Cell Foam Insulation, approved September 15, 2008, IBR approved for §431.304. 

(3) ASTM E741-06, Standard Test Method for Determining Air Change in a Single Zone by 

Means of a Tracer Gas Dilution, approved October 1, 2006 , IBR approved for §431.304. 

(c) AHRI. Air-Conditioning, Heating, and Refrigeration Institute, 2111 Wilson Boulevard, Suite 

500, Arlington, VA 22201, (703) 600-0366, or www.ahrinet.org. 

(1) AHRI Standard 1250P-2009, 2009 Standard for Performance Rating of Walk-In Coolers and 

Freezers, approved September 2009 , IBR approved for §431.304. 

(2) Reserved. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
4. Section 431.304 is revised to read as follows: 

§ 431.304 Uniform test method for the measurement of energy consumption of walk-in 

coolers and walk-in freezers. 

(a) Scope. This section provides test procedures for measuring, pursuant to EPCA, the 

energy consumption of walk-in coolers and walk-in freezers. 

(b) Testing and Calculations. 

(1) Determine the energy consumption of walk-in cooler and walk-in freezer envelopes 

by conducting the test procedure specified in Appendix A to this subpart. 

(2) Determine the U-value of glass components from the product label in compliance 

with the National Fenestration Rating Council’s Product Certification Program, PCP-2007, or by 

using the Window 5.2 software to calculate the performance of the glass. 

(3) Determine the Annual Walk-in Efficiency Factor of walk-in cooler and walk-in 

freezer refrigeration systems by conducting the test procedure set forth in AHRI Standard 1250P2009 (incorporated by reference, see § 431.303). 

(4) Determine the energy consumption of walk-in cooler and walk-in freezer 

refrigeration systems by: 

(i) For refrigeration systems with the condensing unit located inside a conditioned space, 

performing the following calculations for coolers and freezers, respectively: 

0.30  qss (90 F)  8760 Annual Energy Consumption (coolers)  Annual Walk - in Efficiency Factor 

0.53  qss (90 F)  8760 Annual Energy Consumption (freezers)  Annual Walk - in Efficiency Factor 

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where qss(90 °F) is the steady state net refrigeration capacity measured at an ambient condition of 

90 °F, and the Annual Walk-In Efficiency Factor is calculated from the results of the test 

procedures set forth in AHRI Standard 1250P-2009 (incorporated by reference, see § 431.303). 

(ii) For refrigeration systems with the condensing unit located outdoors, performing the 

following calculations for coolers and freezers, respectively: 

n 
 q(95 F)  (t j  35)  ss 

j 1  0.24  qss (95 F) 	 0.06    n j  60   Annual Energy Consumption (coolers)  Annual Walk - in Efficiency Factor 

n 
 q(95 F)  (t j 	10)  ss   0.28  qss (95 F) 	 0.25  105   n j j 1   Annual Energy Consumption (freezers)  Annual Walk - in Efficiency Factor 

where qss(95 °F) is the steady state net refrigeration capacity measured at an ambient condition of 

95 °F; tj and nj represent the outdoor temperature at each bin j and the number of hours in each 

bin j, respectively, for the temperature bins listed in Table D1 of AHRI Standard 1250P-2009 

(incorporated by reference, see § 431.303); and the Annual Walk-In Efficiency Factor is 

calculated from the results of the test procedures set forth in AHRI Standard 1250P-2009 

(incorporated by reference, see § 431.303). 

(iii) For refrigeration systems consisting of a unit cooler connected to a rack system, 

performing the following calculations for coolers and freezers, respectively: 

0.30  qmix,evap  8760

Annual Energy Consumption (coolers)  Annual Walk - in Efficiency Factor 

0.53 qmix,evap  8760

Annual Energy Consumption (freezers) Annual Walk - in Efficiency Factor 

where qmix,evap is the net capacity of the evaporator coil, determined by testing the unit cooler at 

the 25 °F suction dewpoint for a cooler and the -20 °F suction dewpoint for a freezer, at the 

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maximum evaporator fan speed, according to AHRI standard 1250P-2009 (incorporated by 

reference, see § 431.303); and the Annual Walk-in Efficiency Factor is calculated from the 

results of the test procedures set forth in AHRI Standard 1250P-2009 (incorporated by reference, 

see § 431.303). 

5. Appendix A is added to subpart R of part 431 to read as follows: 

APPENDIX A TO SUBPART R OF PART 431—UNIFORM TEST METHOD FOR THE 

MEASUREMENT OF ENERGY CONSUMPTION OF THE ENVELOPES OF WALK-IN 

COOLERS AND WALK-IN FREEZERS 

1.0 SCOPE

This appendix covers the test requirements used to measure the energy consumption of 

the envelopes of walk-in coolers and walk-in freezers. 

2.0 DEFINITIONS

The definitions contained in §431.302 are applicable to this appendix. 

2.1 Additional Definitions 

(a) Unless explicitly stated otherwise, the surface area for all measurements is the area as 

measured on the external surface of the walk-in. 

(b) A device or control system that “automatically” opens and closes doors without direct 

user contact (i.e., a motion sensor that senses when a forklift is approaching the entrance to a 

door, opens, and then closes after the forklift has passed). 

(c) Unless explicitly stated otherwise, all calculations and test procedure measurements shall 

use the temperature and relative humidity data shown in Table A.1. For installations where 

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two or more walk-in envelopes share any surface(s), the “external conditions” of the shared 

surface(s) should reflect the internal conditions of the neighboring walk-in. 

Table A.1 - Temperature and Relative Humidity Conditions 

Internal Conditions (cooled space within envelope) 

Cooler Value Units 

Dry Bulb Temperature 35 F 

 Relative Humidity 60 % 

Freezer 

Dry Bulb Temperature -10 F 

 Relative Humidity 60 % 

External Conditions (space external to the envelope) 

Freezer and Cooler Value Units 

Dry Bulb Temperature 75 F 

 Relative Humidity 40 % 

3.0 TEST APPARATUS AND GENERAL INSTRUCTIONS

3.1 Conduction Heat Gain 

3.1.1 Glass Doors 

(a) All dimensional measurements for glass doors include the door frame and glass. 

(b) Calculate the individual and total glass door surface area (Aglass) as follows: 

A  W  H  n (3-1) glass,i glass,i glass,i i 

i

Aglass, tot  Wglass,i  H glass,i  n i (3-2) 

1 

Where: 

i = index for each type of unique glass door used in cooler or freezer being tested, 

ni = number of identical glass doors of type i, 

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Wglass,i = width of glass door (including door frame), and 

Hglass,i= height of glass door (including door frame). 

(c) Calculate the temperature differential(s) Ti for each unique glass door (F) as follows: 

Ti  TDB,int,i  TDB,ext,i (3-3) 

Where: 

i = Index for each type of unique glass door used in cooler or freezer being tested, 

TDB,int,i = dry-bulb air temperature inside the cooler or freezer, F 

TDB,ext,i = dry-bulb air temperature external to cooler or freezer, F 

(d) Calculate the conduction load through the glass doors, (Qcond-glass,door): 

i

Qcond -glass,door   Aglass,i  Ti  Uglass,i  ni (3-4) 

1 

Where: 

ni = number of identical glass doors of type i; 

Uglass,i = thermal transmittance, U-value of the door, of type i, Btu/ h-ft2

-

o

F; 

Aglass,i = total surface area of all walk-in glass doors of type i, ft2

; and 

 = temperature differential between refrigerated and adjacent zones, F. 

3.1.2 Wall Glass and Doors with Inset Glass 

(a) Calculate the individual and total glass surface area (Aglass,wall), as follows: 

A  W  H  n (3-5) glass, wall,i glass, wall,i glass, wall,,i i 

i

A glass,wall,tot  Wglass,wall,i  Hglass, wall,i  n i (3-6) 

1 

Where: 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
i = index for each type of unique glass door used in cooler or freezer being tested, 

ni = number of identical glass walls or insets of type i, 

Wglass,wall,,i = width of glass wall (including glass framing) 

Hglass,wall,i= height of glass wall (including glass framing) 

(b) Calculate the temperature differential(s) Tglass,wall,i for each unique glass wall (F), as 

follows: 

T  T  T (3-7) glass, wall,i DB,int,glass, wall,i DB,ext,glass, wall,i 

Where: 

i = Index for each type of unique glass door used in cooler or freezer 

TDB,int,glass,wall,i = dry-bulb air temperature inside the cooler or freezer, F 

TDB,ext,glass,wall,i = dry-bulb air temperature external to cooler or freezer, F 

(c) Calculate the conduction load through the glass walls and glass insets, (Qcond-glass,wall) , as 

follows: 

i

Qcond -glass, wall   A glass, wall,,i  Tglass, wall,i  U glass, wall,i  ni (3-8) 

1 

Where: 

ni = number of identical glass walls or insets of type i; 

Uglass,wall,i = thermal transmittance, U-value of the glass wall, of type i, Btu/ h-ft2

-

o

F; 

Aglass,wall,i = total surface area of all walk-in glass walls and insets of type i, ft2

; and 

glass,wall,i= temperature differential between refrigerated and adjacent zones, F. 

3.1.3 Non-Glass Envelope Components 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
(a) Calculate the total surface area of the walk-in non-glass envelope (Anon-glass,tot) , as 

follows: 

i j k l

A non-glass,tot   A walls,i 	  Afloor, j 	  Aceiling,k 	  A non-glass doors,l (3-9) 1 1 1 1 

Where: 

i,j,k,l = number of identical surface area regions of walls, floors, ceilings and non-glass 

doors, respectively, comprised of the same thickness and underlying materials and 

temperature differential--for example, if a walk-in has wall sections that are of 

two different thickness or of two different foam insulation products, i=2; 

Awalls,i = area of walls, of thickness and underlying materials of type i; 

Afloor,j = area of floor, of thickness and underlying materials of type j; 

Aceiling,k = area of ceiling, of thickness and underlying materials of type k; and 

Anon-glass door,l = area of doors, of thickness and underlying materials of type l. 

(b) Determine the R-value (Thermal resistance) of the walls, ceiling, and floor foam per 4.1, 

as follows: 

(c) Calculate the conduction or transmission load through all non-glass components (Qcondnon-glass) , as follows: 

i A walls,i 

j Afloor,j ceiling,k non-glass k A l A doors,l Q cond-non-glass  Ti  	Tj  	Tk  	Tl  1 Rnon-glass,wall,i 1 R non-glass,floor,j 1 Rnon-glass,ceil, k 1 Rnon-glass,door, l 

(3-10) 

Where: 

Rnon-glass,wall, i = R-value of foam used in wall panels, of type i, h-ft2

-

o

F/Btu; 

Rnon-glass,floor, j = R-value of foam used in floor panels, of type j, h-ft2

-

o

F/Btu; 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Rnon-glass,ceil, k = R-value of foam used in ceiling panels, of type k, h-ft2

-

o

F/Btu; 

Rnon-glass,door, l = R-value of foam used in non-glass doors, of type l, h-ft2

-

o

F/Btu; 

Awalls,i = area of wall, of thickness and underlying materials of type i; 

Afloor,j = area of floor, of thickness and underlying materials of type j; 

Aceiling,k = area of ceiling, of thickness and underlying materials of type k; and 

Anon-glass door,l = area of doors, of thickness and underlying materials of type l. 

Ti= dry bulb temperature differential between internal and external air, of type i, F 

Tj= dry bulb temperature differential between internal and external air, of type j, F 

Tk= dry bulb temperature differential between internal and external air, of type k, F 

Tl= dry bulb temperature differential between internal and external air, of type l, F 

3.1.4 Total Conduction Load 

(a) Calculate total conduction load, Qcond, (Btu/h), as follows: 

Qcond  Qcond-non-glass 	 Qcond-glass,wall 	 Qcond-glass,door (3-11) 

Where: 

Qcond-non-glass = conduction load through non-glass components of walk-in, Btu/h; and 

Qcond-glass,wall = total conduction load through walk-in glass walls and inset windows, Btu/h. 

Qcond-glass,door = total conduction load through walk-in glass doors, Btu/h. 

3.2 Infiltration Heat Gain 

3.2.1 Steady State Infiltration Calculations 

(a) Convert dry-bulb internal and external air temperatures from °F to Rankine (°R), as 

follows: 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
TDB-int,R = TDB-int + 459.67 °F (3-12) 

TDB-ext,R = TDB-ext + 459.67 °F (3-13) 

Where: 

TDB-int,R = the dry-bulb temperature of internal walk-in air, °R; and 

TDB-ext,R = the average dry-bulb temperature of air surrounding the walk-in, °R. 

(b) Calculate the water vapor saturation pressure for the external air and the internal 

refrigerated air, as follows: 

(1) If TDB,R < 491.67 °R (32 °F), using following equation to calculate water vapor 

saturation pressure (Pws in psia): 


 C1  2 3 4 

Pws  exp



  	C2 	 C3 TDB,R 	 C4 TDB,R 	 C5 TDB,R 	 C6 TDB,R 	 C7 lnTDB,R 

 TDB,R  

(3-14) 

Where: 

TDB,R = dry-bulb temperature in Rankine (for the internal or external air), 

C1 = – 1.0214165 E+04, 

C2 = – 4.8932428 E+00, 

C3 = – 5.3765794 E–03, 

C4 = 1.9202377 E–07, 

C5 = 3.5575832 E–10, 

C6 = – 9.0344688 E–14, and 

C7 = 4.1635019 E+00. 

(2) If TDB,R > 491.67 °R (32 °F), use the following equation to calculate water vapor 

saturation pressure (Pws in psia): 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001

 C   8 2 3 Pws  exp





T 

 	 C9 	 C10 TDB,R 	 C11 TDB,R 	 C12 TDB,R 	 C13 lnTDB,R  (3-15) 

 DB,R  

Where: 

TDB,R = dry-bulb temperature (for the internal and external air), °R; 

C8 = – 1.0440397 E+04; 

C9 = – 1.1294650 E+01; 

C10 = – 2.7022355 E–02; 

C11 = 1.2890360 E–05; 

C12 = 2.4780681 E–09; and 

C13 = 6.5459673 E+00. 

(c) Calculate the absolute humidity ratio,, as follows: 


0.62198  RH  Pws 

	      14.696  RH  Pws  (3-16) 

Where: 

RH = relative humidity in decimal format (e.g., 0.40 for 40 percent) (for the internal or 

external air), and 

Pws = water vapor saturation pressure. 

(d) Calculate air specific volume, , (ft3

/lb), as follows: 


  0.02521094 2 TDB,R  1 	 1.6078  	
 (3-17) 

Where: 

TDB,R = dry-bulb temperature (for the internal or external air), °R, and 

 = absolute humidity ratio. 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
(e) Calculate air density, air density(lb/ft3

), as follows: 

  


1 (3-18) 

Where: 

 = specific volume of air, ft3/lb. 

(f) Calculate the enthalpy for the internal and external air, h, (Btu/lb), as follows: 

h    T0.240 DB F,     T0.444 DB F, 1061	 		 
 (3-19) 

Where: 

TDB,F = dry-bulb temperature (for the internal or external air), o

F; and 

 absolute humidity ratio. 

(g) Measure the steady-state infiltration rate per 4.2., Vrate (1/h) 

(h) Convert Vrate to V, (ft3

/h) , as follows: 

VV rate  V spaceref (3-20) 

Where: 

Vref-space = the total enclosed volume of the walk-in, ft3 

Vrate = the infiltration rate per 4.2, 1/h 

(i) Calculate the total infiltration load due to steady-state infiltration, Qinfilt, (Btu/h) , as 

follows: 

Q  infilt  ext  hext  int  hint  V (3-21) 

Where: 

V= the infiltration rate measured from 4.2, ft3

/h; 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
int = internal air density, lb/ft3

; 

ext =  external air density, lb/ft3

; 

hint = internal air enthalpy, Btu/lb; and 

hext = external air enthalpy, Btu/lb. 

3.2.2 Door Opening Infiltration Calculations 

(a) Calculate the portion of time each doorway is open, Dt, as follows: 

P  	 60  
 D  p o (3-22) t,i 3600 d 


Where: 

i= index for each unique door. A unique door must be of the same geometry, 

underlying materials, function, and have the same temperature difference across the door 

P = number of doorway passages (i.e., number of doors opening events); 

p = door open-close time, seconds per opening P; 

o = time door stands open, minutes; and 

d = daily time period, h. 

(1) Number of doorway passages: For display glass doors, P = 72 , and all other doors, P= 60 

(2) Door open-close time: For display glass doors, p = 8 seconds. For non-glass doors, if an 

automatic door opener/closer is used, p = 10 seconds and all other doors, p = 15 seconds. 

(3) Time door stands open: Display glass doors, o = 0 minutes and all other doors, o= 15 

minutes 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
(4) Daily time period :All walk-ins, d= 24 hours 

(b) Calculate the density factor, Fm, for each door, as follows: 

3/2 
     2  Fm,i   1/3  (3-23) 

   int,i  1	          ext,i  

Where: 

i= index for each unique door 

 int,i = internal air density, of door type i, lb/ft3; and 

 ext,i = external air density, of door type i, lb/ft3. 

(c) Calculate the infiltration load for fully established flow through each door, qi (Btu/h), as 

follows: 

1/2    ext,i 1/ 2

q  795.6 A (h  h )    



1 

  g  H   F (3-24) i i ext,i int,i int,i i m,i   int,i 

Where: 

i= index for each unique door 

Ai = doorway area, of door type i, ft2; 

hint,i = internal air enthalpy, of door type i, Btu/lb; 

hext,i = external air enthalpy, of door type i, Btu/lb; 

 int,i = internal air density, of door type i, lb/ft3; 

 ext,i = external air density, of door type i, lb/ft3; 

Hi = doorway height, of door type i, ft; 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Fm,i = density factor, of door type i, and 

g = acceleration of gravity, 32.174 ft/s2

. 

(d) Calculate the doorway infiltration reduction device effectiveness, E (%), at the same test 

conditions as described in steady-state infiltration section, as follows: 

(1) A sample set must be taken once the tracer gas has uniformly dispersed in the internal 

space using the methodology described in 4.2. 

(2) The test should be repeated exactly as described with the infiltration reduction device 

removed or deactivated. 

(3) Calculate the infiltration reduction effectiveness: 

Vrate,withdevice E  (3-25) Vrate,withoutdevice

Where: 

Vrate,with-device = air infiltration rate, with door open and reduction device active, using 4.2, 1/h; 

Vrate,without-device = air infiltration rate, with door open and reduction device disabled or removed, 

using 4.2, 1/h. 

(e) Calculate the total door opening infiltration load for a single door, Qopen, (Btu/h), as 

follows: 

Qopen,i  qi  Dt,i  Df  (1  Ei)  ni (3-26) 

Where: 

q = infiltration load for fully established flow, Btu/h; 

Dt = doorway open-time factor; 

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EERE-2008-BT-TP-0014 DOC ID 1.1.001
Df = doorway flow factor, 0.8 for freezers and coolers (from ASHRAE Fundamentals); 

E = effectiveness of doorway protective device, as measured by gas tracer test, %; and 

ni = number of doors (of the type i being considered in calculation). 

(f) Calculate the total load due to door opening infiltration for all doors, Qopen, (Btu/h), as 

follows: 

i

Qopen   Qopen,i (3-27) 

1 

3.3 Energy Consumption Due To Total Heat Gain 

(a) Calculate the total thermal load, Qtot, (Btu/h), as follows: 

Qtot  Qinfilt 	 Qopen 	 Qcond (3-28) 

Where: 

Qinfilt = total load due to steady-state infiltration, Btu/h; 

Qcond = total load due to conduction, Btu/h; and 

Qopen= total load due to door opening infiltration, Btu/h. 

(b) Select Energy Efficiency Ratio (EER) , as follows: 

(1) For coolers, use EER = 12.4 Btu/Wh 

(2) For freezers, use EER = 6.3 Btu/Wh 

(c) Calculate the total daily energy consumption due to thermal load, Qtot,EER, (kWh/day), as 

follows: 

Qtot 24h Qtot 24 kW h Q ,   Qtot,EER    (3-29) tot EER EER 1day1000 EER 1000 W day 

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Where: 

Qtot = total thermal load, Btu/h; and 

EER= EER of walk-in (cooler or freezer), Btu/Wh. 

3.4 Energy Consumption Related To Electrical Components. Electrical components 

contained within a walk-in could include, but are not limited to: heater wire (for anti-sweat or 

anti-freeze application); lights (including display door lighting systems); control system 

units; and sensors. 

3.4.1 Direct Energy Consumption of Electrical Components 

(a) Select the required value for percent time off for each type of electricity consuming 

device, PTOt (%) 

(1) For lights without timers, control system or other demand-based control, PTO=25 

percent. For lighting with timers, control system or other demand-based control, PTO=50 

percent. 

(2) For anti-sweat heaters on coolers (if required): Without timers, control system or other 

demand-based control, PTO=0 percent. With timers, control system or other demand-based 

control, PTO=75 percent. For anti-sweat heaters on freezers (if required): Without timers, 

control system or other auto-shut-off systems, PTO=0 percent. With timers, control system or 

other demand-based control, PTO=50 percent 

(3) For active infiltration reduction devices: Without control by door open or closed position, 

PTO=25 percent. With control by door open or closed position for display doors, PTO=99.33 

percent. With control by door open or closed position for other doors, PTO=99.17 percent. 

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(4) For all other electricity consuming devices: Without timers, control system, or other autoshut-off systems, PTO=0 percent. If it can be demonstrated that the device is controlled by 

preinstalled timers, control system or other auto-shut-off systems, PTO=25 percent. 

(b) Calculate the power usage for each type of electricity consuming device, Pcomp,t, (kWh) , 

as follows: 

Pcomp ,t  Prated ,t  (1  PTOt )  nt  24 (3-30) 

Where: 

t= index for each type of electricity consuming device with identical rated power; 

Prated,t = rated power of each component, of type t, kW; 

PTOt = percent time off, for device of type t, %; and 

nt= number of devices at the rated power of type t. 

(c) Calculate the total electrical energy consumption, Ptot, (kWh), as follows: 

t

P  P (3-31) tot,int comp,int,t

1 

t

Ptot,ext  Pcomp,ext,t (3-32) 

1 

Where: 

t = index for each type of electricity consuming device with identical rated power; 

Pcomp,int, t = the energy usage for an electricity consuming device sited inside the walk-in 

envelope, of type t, kWh. 

Pcomp,ext, t = the energy usage for an electricity consuming device sited outside the walk-in 

envelope, of type t, kWh. 

3.4.2 Total Indirect Electricity Consumption Due to Electrical Devices 

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(a) Calculate the additional compressor load due to thermal output from electrical 

components contained within the envelope, Cload, (kWh), as follows: 

3.412 Btu Cload  Ptot,int  (3-33) EER Wh

Where: 

EER= EER of walk-in (cooler=12.4 or freezer=6.3), Btu/Wh 

Ptot,int= The total electrical load due to components sited inside the walk-in envelope 

3.5 Total Normalized Energy Consumption 

3.5.1 Total Energy Load 

(a) Calculate the total energy load of the walk-in envelope per unit of surface area, Etot 

(kWh/ft2

), as follows: 

QtotAEER 	 Ptot Anonglass,tot 
 Qtot,EER 

E , glass  Etot,non     (3-34) tot non glass Anon glass Anonglass,tot glass 	 A A ,tot 	 A  nonglass,tot glass,tot 

A 
 Q  glass,tot tot,EER Etot,glass     (3-35) Anonglass,tot glass 	 A A ,tot 	 A  nonglass,tot glass,tot 

Ptot load 	 C E  (3-36) tot,electricdevice Anonglass,tot glass 	 A ,tot

Where: 

Qtot,EER= the total thermal load, kWh; 

Ptot= the total electrical load, kWh; 

Anon-glass,tot = total surface area of the non-glass envelope, ft2; 

Aglass,tot = total surface area glass envelope, ft2. 

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Cload= additional compressor load due to thermal output from electrical components 

contained within the envelope, kWh 

4.0 TEST METHODS AND MEASUREMENTS 

4.1 R-Value Testing and Measurements 

4.1.1 Measuring R-Value of Insulating Foam. 

(a) Follow the test procedure in ASTM C1303-08 exactly, except for these exceptions, 

(incorporated by reference, see § 431.303): 

(1) Section 6.6.2, where several types of hot plate methods are recommended, ASTM C518-

04, (incorporated by reference, see § 431.303), must be used for measuring the R-value 

(2) Section 6.6.2.1, in reference to ASTM C518-04, the mean test temperature of the foam 

during R-value measurement must be: 

(i) For freezers: -6.7 +/- 2 °C (20 +/- 4 °F) with a temperature difference of 22 +/- 2 

°C (40 +/- 4 °F) 

(ii) For coolers: 12.8 +/- 2 °C (55 +/- 4 °F) with a temperature difference of 22 +/- 2 

°C (40 +/- 4 °F) 

(b) At least one sample set must be prepared, comprised of three stacks, while adhering to all 

preparation methods and uniformity specifications described in ASTM C1303-08, 

(incorporated by reference, see § 431.303). 

(c) The value resulting LTTR for the foam shall be reported as Rfoam, but for the purposes of 

calculations in this test procedure calculations it will be converted to Rnon-glass, as follows: 

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R non -glass  R foam (4-1) 

Where: 

Rfoam = R-value of foam as measured by ASTM C1303-08, h-ft2-

o

F/Btu-in. 

4.1.2 Determining R-Value of Concrete Floors 

(a) For walk-ins in which the floor is concrete instead of insulated panels and has not been 

supplied by the walk-in manufacturer: 

(1) Coolers: Use an R-value of 0.6 for floors of walk-in coolers. 

(2) Freezers: Use an R-value of 28 for floors of walk-in freezers. 

4.2 Steady State Infiltration Testing 

(a) Follow the test procedure in ASTM E741-06 exactly, except for these changes and 

exceptions to the procedure, (incorporated by reference, see § 431.303): 

(1) Concentration decay method: The “concentration decay method” must be used instead of 

other available options described in ASTM E741-06. 

(2) Gas Tracer: CO2 must be used as the gas tracer for all testing. 

(3) Air change rate: Measure the air change rate in ft3

/h, rather than the air change flow 

described in ASTM E741-06, (incorporated by reference, see § 431.303). 

(4) Spatial measurements: Spatial measurements must be taken in a minimum of six 

locations or one location/20 ft2

 of floor area (whichever results in a greater number of 

measurements) at a height of 3 ft +/- 0.5 ft, at a minimum distance of 2 ft +/- 0.5 ft from the 

walk-in walls or doors. 

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(b) The internal air temperature for freezers and for coolers shall be +/- 2 °C ( 4 °F) of the 

values shown in Table A.1. 

(c) The external air temperature must be 24 °C (75 °F) +/-2.5 °C (5 °F) surrounding the 

walk-in. 

(d) The test must be completed with all reach or walk-in doors closed. 

(e) For testing the effectiveness ASTM E741-06 will used, with the following changes or 

exceptions to the procedure: 

(1) Within 3 minutes +/- 30 seconds, with the infiltration reduction device in place, a hinged 

door should be opened at an angle greater than or equal to 90 degrees. The elapsed time, 

from zero degrees position (closed) to greater than or equal to 90 degrees (open) must be no 

longer than 5 seconds. The door must then be then held at an angle greater than or equal to 90 

degrees for 5 min +/- 5 seconds and then closed over a period no longer than 5 seconds. For 

non-hinged doors, the door must reach its maximum opened position, be held open, and 

reach a fully closed position for the same elapsed time as described above for hinge-type 

doors. 

(2) The gas concentration must be sampled again after the door has been closed. Samples 

should continue being taken until the gas concentration is once again uniform within the 

walk-in. 

5.0 CALCULATION OF DAILY ENERGY CONSUMPTION COEFFICIENTS (DECC) 

The calculation procedures described in this section are based on the test measurements and 

other performance parameters discussed and described in the previous sections. The Daily 

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Energy Consumption Coefficients are each combined to provide a linear expression of the 

daily energy consumption of any walk-in system with the construction features or component 

design parameters of a tested walk-in design with similar components and features. The 

DECC figures established using measurements on the test unit may be used to derive the 

daily electrical energy consumption of other walk-in systems in the same class constructed 

with similar components of construction as follows: 

E tot,system non-glass non-glass,tot glass glass,tot infilt,disp_dr_op  DECC A + DECC A + DECC n disp_doors A +

DECC disp_dr_device disp_doors infilt,non-display, n 	 DECC dr_opn non-display-doors non-display-dr_device non-display-doors A + DECC n 	

DECC light ref_space ASH disp_doors stir_fan ref_space other ref_space V + DECC  A + DECC V + DECC V

(5-1) 

Where: 

DECCnon-glass= DECC for non-glass, 

Anon-glass,tot= total non-glass surface area, 

DECCglass,door= DECC for glass doors, 

Aglass,glass, tot= total glass surface area, and 

DECCglass,wall= DECC for glass walls and inset windows, 

Aglass,wall, tot= total glass wall and inset window surface area, and 

DECCinfilt,disp_dr_opn= DECC for opening of display type doors, 

Adisp_doors= total area of display doors, 

DECC disp_dr_device= DECC for infiltration reduction device in place for display doors,

 ndisp_doors= total number of display doors, 

DECCinfilt,non-display_,dr_opn = DECC for non-display type doors, 

Anon-display_doors= total area of non-display type doors, 

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DECCnon-display_dr_device= DECC for infiltration reduction device in place for non-display 

doors,

 nnon-display_doors= total number of non-display doors, 

DECClight= DECC for lights, 

Vref_space= total enclosed refrigerated volume(ft3), 

DECCASH= DECC for anti-sweat heaters, 

DECCstir_fan= DECC for motors used to drive air mixing fans, and 

DECCother= DECC for other electricity consuming devices. 

(a) Calculate DECCnon-glass as follows: 

Anonglass,tot Qtot,non-glass = Qcond, non-glass + Qinfilt  (5-2) Anonglass,tot glass 	 A ,tot glass 	 A ,wall,tot

Qtot,non-glass 24 h kW Ethermal,non-glass    (5-3) EER 1000 day W 

Ethermal,nonglass DECC non-glass  Anonglass,tot (5-4) 

Where: 

Qcond,non-glass= conduction load due to non-glass surface area, 

Qcond,glass,wall= conduction load due to glass wall and inset window surface area, 

Qcond,glass,door= conduction load due to glass door surface area, 

Qinfilt= load due to steady-state infiltration, 

Anon-glass,tot= total non-glass surface area, 

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Aglass,wall,tot= total glass wall and inset window surface area, 

Aglass,door,tot= total glass door surface area, 

EER= energy efficiency ratio for freezer or cooler, as described 3.3(b) 

(b) Calculate DECCglass,door as follows: 

Aglass,door,tot Qtot,glass,door = Qcond, glass,door + Qinfilt  (5-5) Anonglass,tot glass 	 A ,door,tot glass 	 A ,wall,tot

Qtot,glass,door 24 h kW Ethermal,glass,door    (5-6) EER 1000 day W

Ethermal,glass,door DECCglass,door  (5-7) Aglass,door,tot

Where: 

Qcond,non-glass= conduction load due to non-glass surface area, 

Qcond,glass,wall= conduction load due to glass wall and inset window surface area, 

Qcond,glass,door= conduction load due to glass door surface area, 

Qinfilt= load due to steady-state infiltration, 

Anon-glass,tot= total non-glass surface area, 

Aglass,wall,tot= total glass wall and inset window surface area, 

Aglass,door,tot= total glass door surface area, 

EER= energy efficiency ratio for freezer or cooler, as described 3.3(b) 

(c) Calculate DECCglass,wall as follows: 

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Aglass,wall,tot Qtot,glass,wall = Qcond, glass,wall + Qinfilt  (5-8) Anonglass,tot glass 	 A ,door,tot glass 	 A ,wall,tot

Qtot,glass,wall 24 h kW Ethermal,glass,wall    (5-9) EER 1000 day W

Ethermal,glass DECCglass,wall  (5-10) Aglass,wall,tot

Where: 

Qcond,non-glass= conduction load due to non-glass surface area, 

Qcond,glass,wall= conduction load due to glass wall and inset window surface area, 

Qcond,glass,door= conduction load due to glass door surface area, 

Qinfilt= load due to steady-state infiltration, 

Anon-glass,tot= total non-glass surface area, 

Aglass,wall,tot= total glass wall and inset window surface area, 

Aglass,door,tot= total glass door surface area, 

EER= energy efficiency ratio for freezer or cooler, as described 3.3(b) 

(d) Compute DECCglass in an identical manner to DECCglass,door, described above. 

(e) Compute DECCinfilt,disp_dr_opn and DECC disp_dr_device as follows: 

Qopen,disp_dr 24hr Einfilt,disp_dr_opn   (5-11) EER 1000 

Einf ilt,disp _ dr _ opn DECCinfilt,disp_dr_opn  A (5-12) 

display _ dr

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Where: 

Qopen,disp_dr= total infiltration load calculated for display door-opening events, and 

EER= energy efficiency ratio for freezer or cooler 

(f) Determine DECC disp_dr_device as follows: 

(1) For passive infiltration reduction devices (e.g., strip curtains), the DECC disp_dr_device is 

zero. 

(2) For active infiltration reduction devices (e.g., air curtains), DECCdisp_dr_device = Pcomp

where Pcomp is determined as in section 3.4.1 using the appropriate PTO (percent time off) 

(g) Compute DECCinfilt, non-display_dr_opn and DECC non-display_dr_device in the same manner as 

DECCinfilt, disp_dr_opn and DECC disp_dr_device above. 

(h) Compute DECCASH in the following manner: 

Pcomp, ASH DECC ASH = (5-13) Adisp-door 

Where: 

Pcomp, ASH= total energy consumed by anti-sweat heaters (per section 3.4.1), and 

Adisp-door= total surface area of display doors. 

(i) Compute DECCstir_fan , for stirring (non-evaporator) fans in the following manner: 

Pcomp,stir_fan DECC = (5-14) stir_fan Vref_space 

Where 

Vref_space= total volume of the refrigerated space (ft3

), and 

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Pcomp,stirring_fan total energy consumed by stir fan(s) (per 3.4.1). 

(j) Compute DECCother for all other electricity consuming devices: For all lights and other 

electrical loads, Pcomp,j is determined per the provisions of the section 3.4.1 and the DECCother 

is obtained by dividing the respective Pcomp,j by Vref_spac.

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