[Federal Register Volume 87, Number 38 (Friday, February 25, 2022)]
[Proposed Rules]
[Pages 10726-10751]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-03484]


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DEPARTMENT OF ENERGY

10 CFR Part 431

[EERE-2019-BT-TP-0041]
RIN 1904-AE57


Energy Conservation Program: Test Procedure for Commercial Warm 
Air Furnaces

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

ACTION: Notice of proposed rulemaking and announcement of public 
meeting.

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SUMMARY: The U.S. Department of Energy (``DOE'') proposes to amend the 
test procedures for commercial warm air furnaces (``CWAFs'') to 
incorporate the latest versions of the industry standards that are 
currently incorporated by reference. DOE also proposes to establish a 
new metric, Thermal Efficiency Two (``TE2''), and corresponding test 
procedure. Use of the newly proposed test procedure would become 
mandatory at such time as compliance with amended energy conservation 
standards based on TE2 is required, should DOE adopt such standards. 
DOE also proposes additional specifications for CWAFs with multiple 
vent hoods or small-diameter vent hoods. DOE is seeking comment from 
interested parties on the proposal.

DATES: DOE will accept comments, data, and information regarding this 
proposal no later than April 26, 2022. See section V, ``Public 
Participation,'' for details. DOE will hold a webinar on Tuesday, March 
29, 2022, from 1:00 p.m. to 5:00 p.m. See section V, ``Public 
Participation,'' for webinar registration information, participant 
instructions, and information about the capabilities available to 
webinar participants. If no participants register for the webinar, it 
will be cancelled.

ADDRESSES: Interested persons are encouraged to submit comments using 
the Federal eRulemaking Portal at www.regulations.gov. Follow the 
instructions for submitting comments. Alternatively, interested persons 
may submit comments, identified by docket

[[Page 10727]]

number EERE-2019-BT-TP-0041, by any of the following methods:
    1. Federal eRulemaking Portal: www.regulations.gov. Follow the 
instructions for submitting comments.
    2. Email: to <a href="/cdn-cgi/l/email-protection#3f794a4d515e5c5a4c0d0f0e066b6f0f0f0b0e7f5a5a115b505a11585049"><span class="__cf_email__" data-cfemail="0e487b7c606f6d6b7d3c3e3f375a5e3e3e3a3f4e6b6b206a616b20696178">[email protected]</span></a>. Include docket number 
EERE-2019-BT-TP-0041 in the subject line of the message.
    No telefacsimiles (``faxes'') will be accepted. For detailed 
instructions on submitting comments and additional information on this 
process, see section V of this document.
    Although DOE has routinely accepted public comment submissions 
through a variety of mechanisms, including postal mail and hand 
delivery/courier, the Department has found it necessary to make 
temporary modifications to the comment submission process in light of 
the ongoing coronavirus 2019 (``COVID-19'') pandemic. DOE is currently 
suspending receipt of public comments via postal mail and hand 
delivery/courier. If a commenter finds that this change poses an undue 
hardship, please contact Appliance Standards Program staff at (202) 
586-1445 to discuss the need for alternative arrangements. Once the 
COVID-19 pandemic health emergency is resolved, DOE anticipates 
resuming all of its regular options for public comment submission, 
including postal mail and hand delivery/courier.
    Docket: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts (if a public meeting is held), 
comments, and other supporting documents/materials, is available for 
review at www.regulations.gov. All documents in the docket are listed 
in the www.regulations.gov index. However, some documents listed in the 
index, such as those containing information that is exempt from public 
disclosure, may not be publicly available.
    The docket web page can be found at www.regulations.gov/document?D=EERE-2019-BT-TP-0041-0001. The docket web page contains 
instructions on how to access all documents, including public comments, 
in the docket. See section V for information on how to submit comments 
through www.regulations.gov.

FOR FURTHER INFORMATION CONTACT:

Ms. Julia Hegarty, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Office, EE-5B, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(240) 567-6737. Email: <a href="/cdn-cgi/l/email-protection#fdbc8d8d91949c939e98ae899c93999c8f998eac88988e899492938ebd9898d3999298d39a928b"><span class="__cf_email__" data-cfemail="85c4f5f5e9ece4ebe6e0d6f1e4ebe1e4f7e1f6d4f0e0f6f1eceaebf6c5e0e0abe1eae0abe2eaf3">[email protected]</span></a>.
Ms. Amelia Whiting, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121. 
Telephone: (202) 586-2588. Email: <a href="/cdn-cgi/l/email-protection#6c2d010900050d423b04051805020b2c041d42080309420b031a"><span class="__cf_email__" data-cfemail="2a6b474f46434b047d42435e43444d6a425b044e454f044d455c">[email protected]</span></a>.

    For further information on how to submit a comment, review other 
public comments and the docket, or participate in a public meeting (if 
one is held), contact the Appliance and Equipment Standards Program 
staff at (202) 287-1445 or by email: 
<a href="/cdn-cgi/l/email-protection#b1f0c1c1ddd8d0dfd2d4e2c5d0dfd5d0c3d5c2e0c4d4c2c5d8dedfc2f1d4d49fd5ded49fd6dec7"><span class="__cf_email__" data-cfemail="65241515090c040b06003611040b010417011634100016110c0a0b162500004b010a004b020a13">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: DOE proposes to incorporate by reference the 
following industry standards into 10 CFR part 431:
    American National Standards Institute (``ANSI'') Z21.47-2021, 
``Gas-fired Central Furnaces'';
    ANSI/The American Scociety of Mechanical Engineers (``ASME'') PTC 
19.3-1974 (R2004), ``Part 3: Temperature Measurement, Instruments and 
Apparatus'';
    ANSI/American Society of Heating, Refrigeration, and Air-
conditioning Engineers (``ASHRAE'') Standard 103-2017, ``Method of 
Testing for Annual Fuel Utilization Efficiency of Residential Central 
Furnaces and Boilers'';
    Copies of ANSI Z21.47-2021, ANSI/ASME PTC 19.3-1974 (R2004) and 
ANSI/ASHRAE 103-2017, can be obtained from American National Standards 
Institute, 25 W 43rd Street, 4th Floor, New York, NY 10036, (212) 642-
4900, or online at: webstore.ansi.org.
    Underwriters Laboratories (``UL'') standard UL 727-2018 ``Standard 
for Safety Oil-Fired Central Furnaces'';
    Copies of UL 727-2018 can be obtained from Underwriters 
Laboratories, Inc., 2600 NW, Lake Rd., Camas, WA 98607-8542, (360) 817-
5500 or online at: standardscatalog.ul.com.
    ANSI/Air-Conditioning, Heating, and Refrigeration Institute 
(``AHRI'') 1500-2015 ``Performance Rating of Commercial Space Heating 
Boilers'';
    Copies of AHRI 1500-2015 can be obtained from Air-Conditioning, 
Heating, and Refrigeration Institute, 2111 Wilson Blvd., Suite 500, 
Arlington, VA 22201, (703) 524-8800, or online at: ahrinet.org.
    ANSI/ASTM E230/E230M-17 ``Standard Specification for Temperature-
Electromotive Force (emf) Tables for Standardized Thermocouples'';
    ASTM D240-09 ``Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter'';
    ASTM D396-14a ``Standard Specification for Fuel Oils'';
    ASTM D4809-09a ``Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)'';
    ASTM D5291-10 ``Standard Test Methods for Instrumental 
Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products 
and Lubricants'';
    Copies of ANSI/ASTM E230/E230M-17, ASTM D240-09, ASTM D396-14a, 
ASTM D4809-09a, and ASTM D5291-10, and can be obtained from ASTM, 
International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, 
PA 19428, (877) 909-2786 or by going online at: www.astm.org.
    National Fire Protection Association (``NFPA'') 97-2003 ``Standard 
Glossary of Terms Relating to Chimneys, Vents, and Heat-Producing 
Appliances''.
    Copies of NFPA 97-2003 can be obtained from National Fire 
Protection Association, 1 Batterymarch Park, Quincy, MA 02169-7471, 
(617) 770-3000 or by going online at: www.nfpa.org.
    For a further discussion of these standards, see section IV.M of 
this document.

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
    C. Deviation From Appendix A
II. Synopsis of the Notice of Proposed Rulemaking
III. Discussion
    A. Scope of Applicability
    B. Updates to Industry Standards
    1. UL 727-2006
    2. HI BTS-2000
    3. ANSI Z21.47
    4. ANSI/ASHRAE 103
    C. ``Thermal Efficiency Two'' Metric
    1. Jacket Loss
    2. Part-Load Performance
    D. Electrical Energy Consumption
    E. Other Test Procedure Updates and Clarifications
    1. Flue Temperature Measurement in Models With Multiple Vent 
Hoods
    2. Flue Temperature Measurement in Models With Vent Space 
Limitations
    3. Input Rate Tolerance
    4. Flue Loss Determination
    F. Test Procedure Costs, Harmonization, and Other Topics
    1. Test Procedure Costs and Impact
    2. Harmonization With Industry Standards
    G. Compliance Date
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Order 12866
    B. Review Under the Regulatory Flexibility Act
    1. Description of Why Action Is Being Considered
    2. Objective of, and Legal Basis for, Rule

[[Page 10728]]

    3. Description and Estimate of Small Entities Regulated
    4. Description and Estimate of Compliance Requirements
    5. Duplication Overlap, and Conflict With Other Rules and 
Regulations
    6. Significant Alternatives to the Rule
    C. Review Under the Paperwork Reduction Act of 1995
    D. Review Under the National Environmental Policy Act of 1969
    E. Review Under Executive Order 13132
    F. Review Under Executive Order 12988
    G. Review Under the Unfunded Mandates Reform Act of 1995
    H. Review Under the Treasury and General Government 
Appropriations Act, 1999
    I. Review Under Executive Order 12630
    J. Review Under Treasury and General Government Appropriations 
Act, 2001
    K. Review Under Executive Order 13211
    L. Review Under Section 32 of the Federal Energy Administration 
Act of 1974
    M. Description of Materials Incorporated by Reference
V. Public Participation
    A. Participation in the Webinar
    B. Procedure for Submitting Prepared General Statements for 
Distribution
    C. Conduct of the Webinar
    D. Participation in the Webinar
    E. Issues on Which DOE Seeks Comment
VI. Approval of the Office of the Secretary

I. Authority and Background

    CWAFs are included in the list of ``covered equipment'' for which 
DOE is authorized to establish and amend energy conservation standards 
and test procedures. (42 U.S.C. 6311(1)(J)) DOE's energy conservation 
standards and test procedures for CWAFs are currently prescribed at 
subpart D of part 431 of title 10 of the Code of Federal Regulations 
(``CFR''). The following sections discuss DOE's authority to establish 
test procedures for CWAFs and relevant background information regarding 
DOE's consideration of test procedures for this equipment.

A. Authority

    The Energy Policy and Conservation Act, as amended (``EPCA''),\1\ 
authorizes DOE to regulate the energy efficiency of a number of 
consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C \2\ of EPCA, added by Public Law 95-619, Title 
IV, section 441(a), established the Energy Conservation Program for 
Certain Industrial Equipment, which sets forth a variety of provisions 
designed to improve energy efficiency. (42 U.S.C. 6311-6317) This 
equipment includes CWAFs, the subject of this document. (42 U.S.C. 
6311(1)(J))
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    \1\ All references to EPCA in this document refer to the statute 
as amended through the Infrastructure Investment and Jobs Act, 
Public Law 117-58 (Nov. 15, 2021).
    \2\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
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    The energy conservation program under EPCA consists essentially of 
four parts: (1) Testing, (2) labeling, (3) Federal energy conservation 
standards, and (4) certification and enforcement procedures. Relevant 
provisions of EPCA include definitions (42 U.S.C. 6311), test 
procedures (42 U.S.C. 6314), labeling provisions (42 U.S.C. 6315), 
energy conservation standards (42 U.S.C. 6313), and the authority to 
require information and reports from manufacturers (42 U.S.C. 6316; 42 
U.S.C. 6296).
    The Federal testing requirements consist of test procedures that 
manufacturers of covered equipment must use as the basis for: (1) 
Certifying to DOE that their equipment complies with the applicable 
energy conservation standards adopted pursuant to EPCA (42 U.S.C. 
6316(b); 42 U.S.C. 6296), and (2) making representations about the 
efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE uses 
these test procedures to determine whether the equipment complies with 
relevant standards promulgated under EPCA.
    Federal energy efficiency requirements for covered equipment 
established under EPCA generally supersede State laws and regulations 
concerning energy conservation testing, labeling, and standards. (42 
U.S.C. 6316(a) and (b); 42 U.S.C. 6297) DOE may, however, grant waivers 
of Federal preemption for particular State laws or regulations, in 
accordance with the procedures and other provisions of EPCA. (42 U.S.C. 
6316(b)(2)(D); 42 U.S.C. 6297(d))
    Under 42 U.S.C. 6314, EPCA sets forth the criteria and procedures 
DOE must follow when prescribing or amending test procedures for 
covered equipment. EPCA requires that any test procedures prescribed or 
amended under this section must be reasonably designed to produce test 
results which reflect energy efficiency, energy use or estimated annual 
operating cost of a given type of covered equipment during a 
representative average use cycle and requires that test procedures not 
be unduly burdensome to conduct. (42 U.S.C. 6314(a)(2))
    EPCA requires that the test procedure for CWAFs be those generally 
accepted industry testing procedures developed or recognized by the 
Air-Conditioning, Heating, and Refrigeration Institute (AHRI) or by the 
American Society of Heating, Refrigerating and Air-Conditioning 
Engineers (ASHRAE), as referenced in ASHRAE Standard 90.1. (42 U.S.C. 
6314(a)(4)(A)) Further, if such industry test procedure is amended, DOE 
must amend its test procedure to be consistent with the amended 
industry test procedure, unless DOE determines, by rule published in 
the Federal Register and supported by clear and convincing evidence, 
that such amended test procedure would not meet the requirements in 42 
U.S.C. 6314(a)(2) and (3) related to representative use and test 
burden, in which case DOE may establish an amended test procedure that 
does satisfy those statutory provisions. (42 U.S.C. 6314(a)(4)(B) and 
(C))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including CWAF, to 
determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
6314(a)(1))
    If the Secretary determines that a test procedure amendment is 
warranted, the Secretary must publish proposed test procedures in the 
Federal Register and afford interested persons an opportunity (of not 
less than 45 days' duration) to present oral and written data, views, 
and arguments on the proposed test procedures. (42 U.S.C. 6314(b)) If 
DOE determines that test procedure revisions are not appropriate, DOE 
must publish its determination not to amend the test procedures. DOE is 
publishing this notice of proposed rulemaking (``NOPR'') in 
satisfaction of the 7-year review requirement specified in EPCA. (42 
U.S.C. 6314(a)(1)(A)(ii))

B. Background

    DOE's current test procedure for CWAFs is codified at 10 CFR 
431.76, ``Uniform test method for the measurement of energy efficiency 
of commercial warm air furnaces.'' The currently applicable test 
procedure incorporates by reference two industry standards for testing 
gas-fired CWAFs: American National Standards Institute (``ANSI'') 
Z21.47-2012, ``Standard for Gas-fired Central Furnaces'' (``ANSI 
Z21.47-2012''), which is used for all types of gas-fired CWAFs; and 
ANSI/American Society of Heating, Refrigeration, and Air-conditioning 
Engineers (``ASHRAE'') Standard 103-2007, ``Method of Testing for 
Annual Fuel Utilization Efficiency of Residential Central Furnaces and 
Boilers'' (``ANSI/ASHRAE 103-2007''), which is specifically used for 
testing condensing gas-fired CWAFs. 10 CFR

[[Page 10729]]

431.76 (c)(1), (d)(2), (e)(1), and (f)(1);10 CFR 431.75(b)(1) and 
(c)(1). The current test procedure also incorporates by reference two 
industry standards for testing oil-fired CWAFs: Hydronics Institute 
Division of AHRI (``HI'') BTS-2000 Rev 06.07, ``Method to Determine 
Efficiency of Commercial Space Heating Boilers'' (``HI BTS-2000'') \3\ 
and Underwriters Laboratories (``UL'') UL 727-2006, ``Standard for 
Safety Oil-Fired Central Furnaces'' (``UL 727-2006'').\4\ 10 CFR 
431.76(c)(2), (d)(1), and (e)(2); 10 CFR 471.75(d)(1) and (e)(2).
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    \3\ DOE determined that UL 727-1994 did not provide a procedure 
for calculating the percent flue loss of the furnace, which is 
necessary in calculating the thermal efficiency, and therefore 
incorporated by reference provisions from HI BTS-2000 to calculate 
the flue loss for oil-fired CWAFs. 69 FR 61916, 61917, 61940 (Oct. 
21, 2004).
    \4\ UL 727-1994 is also incorporated by reference in 10 CFR 
431.75, but is no longer referenced in the test method specified in 
10 CFR 431.76, which references only UL 727-2006.
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    DOE most recently amended the test procedure for CWAFs in a final 
rule published on July 17, 2015, which updated the test procedure for 
gas-fired CWAFs to incorporate by reference the latest versions of the 
industry standards available at the time (i.e., ANSI Z21.47-2012 and 
ANSI/ASHRAE 103-2007). 80 FR 42614 (``July 2015 final rule''). At the 
time of the July 2015 final rule, UL 727-2006 and HI BTS-2000 were 
still the most recent versions of those industry standards.
    On May 5, 2020, DOE published a request for information (``RFI'') 
soliciting public comments, data, and information on aspects of the 
existing DOE test procedure for CWAFs, including whether there are any 
issues with the current test procedure and whether it is in need of 
updates or revisions. 85 FR 26626 (``May 2020 RFI'').
    DOE received comments in response to the May 2020 RFI from the 
interested parties listed in Table I.1.

  Table I.1--Written Comments Received in Response to the May 2020 RFI
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                                        Reference in
            Commenter(s)                  this NOPR      Commenter type
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Appliance Standards Awareness         ASAP............  Efficiency
 Project.                                                Organization.
Northwest Energy Efficiency Alliance  NEEA............  Efficiency
                                                         Organization.
Pacific Gas and Electric Company,     CA IOUs.........  Utility
 Southern California Gas Company,                        Organization.
 Southern California Edison, and San
 Diego Gas and Electric Company
 (collectively, the ``California
 Investor-Owned Utilities'').
Air-Conditioning, Heating, and        AHRI............  Trade
 Refrigeration Institute.                                Association.
American Public Gas Association.....  APGA............  Trade
                                                         Association.
Carrier Corporation.................  Carrier.........  Manufacturer.
Trane Technologies..................  Trane...........  Manufacturer.
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    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\5\
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    \5\ The parenthetical reference provides a reference for 
information located in the docket of DOE's rulemaking to develop 
test procedures for CWAFs. (Docket No. EERE-2019-BT-TP-0041, which 
is maintained at www.regulations.gov). The references are arranged 
as follows: (Commenter name, comment docket ID number, page of that 
document).
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C. Deviation From Appendix A

    In accordance with section 3(a) of 10 CFR part 430, subpart C, 
appendix A (``appendix A''), DOE notes that it is deviating from the 
provision in appendix A regarding the pre-NOPR stages for a test 
procedure rulemaking. See 86 FR 70892 (Dec. 13, 2021) (effective 
January 12, 2022). Section 8(b) of appendix A states if DOE determines 
that it is appropriate to continue the test procedure rulemaking after 
the early assessment process, it will provide further opportunities for 
early public input through Federal Register documents, including 
notices of data availability and/or RFIs. DOE is opting to deviate from 
this provision due to the substantial feedback and information supplied 
by commenters in response to the May 2020 RFI.
    As discussed in section I.B of this NOPR, the May 2020 RFI 
requested submission of such comments, data, and information pertinent 
to test procedures for CWAFs. In response to the May 2020 RFI, 
stakeholders provided substantial comments and information, which DOE 
has found sufficient to identify the need to modify the test procedures 
for CWAFs. Section III of this NOPR discusses in detail the comments 
received and how early stakeholder feedback has been considered in 
forming DOE's proposals to amend the CWAF test procedure.

II. Synopsis of the Notice of Proposed Rulemaking

    In this NOPR, DOE proposes to update its test procedures for CWAFs 
as follows:
    (1) Reorganize the setup and testing provisions in 10 CFR 431.76 
related to the determination of thermal efficiency into the newly 
established 10 CFR part 431, subpart D, appendix A (``appendix A'');
    (2) Incorporate by reference the most recent versions of the 
currently referenced industry standards:
    <bullet> UL 727-2018 (previously UL 727-2006) for testing oil-fired 
CWAFs;
    <bullet> AHRI 1500-2015 (previously HI BTS-2000) for performing 
fuel oil analysis and for calculating flue loss of oil-fired CWAFs;
    <bullet> ANSI Z21.47-2021 (previously ANSI Z21.47-2012) for testing 
gas-fired CWAFs; and
    <bullet> ANSI/ASHRAE 103-2017 (previously ANSI/ASHRAE 103-2007) for 
testing condensing gas-fired CWAFs;
    (3) Incorporate by reference the standards referenced in UL 727-
2018 (i.e., NFPA 97-2003), AHRI 1500-2015 (i.e., ASTM D396-14a, ASTM 
D240-09, ASTM D4809-09a, and ASTM D5291-10), and ANSI Z21.47-2021 
(i.e., ANSI/ASME PTC 19.3-1974 (R2004)) that are necessary for 
performing the DOE test procedure;
    (4) Clarify how to test units with multiple vent hoods, and units 
with vent hoods that are 2 inches or smaller in diameter; and
    (5) Establish a new test procedure at 10 CFR part 431, subpart D, 
appendix B (``appendix B''), which would generally require testing as 
in appendix A, but which would establish a new metric, ``TE2.'' The new 
TE2 metric would account for jacket losses and part-load operation in 
addition to accounting for flue losses. If adopted, manufacturers could 
use proposed new appendix B to make voluntary representations of TE2; 
this proposed test procedure would become mandatory at such time as 
compliance is required with amended energy conservation standards based 
on TE2, should DOE adopt such standards.

[[Page 10730]]

    DOE's proposed actions are summarized in Table II.1 compared to the 
current test procedure as well as the reason for the proposed change.

          Table II.1--Summary of Changes in Proposed Test Procedures Relative to Current Test Procedure
----------------------------------------------------------------------------------------------------------------
    Current DOE test procedure       Proposed test procedures    Applicable test procedure       Attribution
----------------------------------------------------------------------------------------------------------------
References UL 727-2006 for testing  Incorporate by reference    Appendix A and appendix B.  Align with industry
 oil-fired CWAFs.                    UL 727-2018 for testing                                 standard update.
                                     oil-fired CWAFs, and the
                                     standards referenced in
                                     UL 727-2018 that are
                                     necessary in performing
                                     the DOE test procedure
                                     (i.e., NFPA 97-2003).
References HI BTS-2000 for          Incorporate by reference    Appendix A and appendix B.  Align with industry
 performing fuel oil analysis and    AHRI 1500-2015 for                                      standard update.
 for calculating flue loss of oil-   performing fuel oil
 fired CWAFs.                        analysis and for
                                     calculating flue loss of
                                     oil-fired CWAFs and the
                                     standards referenced in
                                     AHRI 1500-2015 that are
                                     necessary in performing
                                     the DOE test procedure
                                     (i.e., ASTM D396-14a,
                                     ASTM D240-09, ASTM D4809-
                                     09a, and ASTM D5291-10).
References ANSI Z21.47-2012 for     Incorporate by reference    Appendix A and appendix B.  Align with industry
 testing gas-fired CWAFs.            ANSI Z21.47-2021 for                                    standard update.
                                     testing gas-fired CWAFs,
                                     and the standards
                                     referenced in ANSI Z21.47-
                                     2021 that are necessary
                                     in performing the DOE
                                     test procedure (i.e.,
                                     ANSI/ASME PTC 19.3-1974
                                     (R2004)).
References ANSI/ASHRAE 103-2007     Incorporate by reference    Appendix A and appendix B.  Align with industry
 for testing condensing gas-fired    ANSI/ASHRAE 103-2017 for                                standard update.
 CWAFs.                              testing condensing gas-
                                     fired CWAFs.
Does not specify how to test units  Adds specifications for     Appendix A and appendix B.  Additional
 with multiple vent hoods.           units with multiple vent                                specification to
                                     hoods. Measurements made                                improve consistency
                                     in each vent hood shall                                 and repeatability
                                     be averaged or adjusted                                 in testing.
                                     using a weighted average,
                                     depending on the flue
                                     hood face area.
Does not specify how to test units  Adds specifications to      Appendix A and appendix B.  Additional
 with vent hoods that are too        address units with small-                               specification to
 small to fit nine thermocouples.    diameter vent hoods.                                    improve consistency
                                     Units with vent hoods                                   and repeatability
                                     that are 2 inches or                                    in testing.
                                     smaller in diameter may
                                     optionally use 5
                                     thermocouples.
Efficiency metric (TE) only         Establishes a new metric    Appendix B................  Improve
 accounts for flue losses and does   (TE2) that accounts for                                 representativeness.
 not account for jacket losses or    flue losses, jacket
 part-load operation.                losses, and part-load
                                     operation.
----------------------------------------------------------------------------------------------------------------

    DOE has tentatively determined that the proposed amendments for the 
test procedure at appendix A described in section III of this document 
would not alter the measured efficiency of CWAFs, that the proposed 
test procedures would not be unduly burdensome to conduct, and that the 
proposed test procedures more accurately produce test results that 
reflect energy efficiency, energy use, and estimated operating costs of 
CWAFs during a representative average use cycle.
    The additional proposed amendments for the newly proposed appendix 
B would alter the reported efficiency of CWAFs, as discussed in the 
relevant section of this document. However, as proposed, testing in 
accordance with these specific proposed changes would not be required 
until such time as compliance is required with any amended energy 
conservation standards based on appendix B.
    Discussion of DOE's proposed actions are discussed in detail in 
section III of this document.

III. Discussion

    In the following sections, DOE describes the proposed amendments to 
the test procedures for CWAFs. DOE seeks input from the public to 
assist with its consideration of the proposed amendments presented in 
this document. In addition, DOE welcomes comments on other relevant 
issues that may not specifically be identified in this document.

A. Scope of Applicability

    This rulemaking applies to CWAFs. EPCA defines ``warm air furnace'' 
as a self-contained oil-fired or gas-fired furnace designed to supply 
heated air through ducts to spaces that require it and includes 
combination warm air furnace/electric air conditioning units, but does 
not include unit heaters and duct furnaces. (42 U.S.C. 6311(11)(A)) DOE 
codified the statutory definition of ``warm air furnace'' at 10 CFR 
431.72. DOE defines a CWAF as a warm air furnace that is industrial 
equipment, and that has a capacity (rated maximum input) of 225,000 
British thermal units (``Btu'') per hour or more. 10 CFR 431.72.
    DOE did not receive any comments in response to the May 2020 RFI 
related to the scope of the CWAF test procedure or relevant definitions 
for CWAFs. DOE is not proposing any changes to the scope of equipment 
covered by its CWAF test procedures, or to the relevant definitions.

B. Updates to Industry Standards

    As discussed, DOE currently incorporates by reference in 10 CFR 
part 431, subpart D, the following industry test procedures: UL 727-
2006, HI-BTS 2000, ANSI Z21.47-2012, and ANSI/ASHRAE Standard 103-2007. 
Updates of each of these test standards have been published since they 
were incorporated into the current test procedure. These updated test 
standards are UL 727-2018 (update to UL 727-2006), AHRI 1500-2015 
(update to HI-BTS 2000), ANSI Z21.47-2021 \6\ (update to ANSI Z21.47-
2016), and ANSI/ASHRAE Standard 103-2017 (update to ANSI/ASHRAE 
Standard 103-2007).
---------------------------------------------------------------------------

    \6\ At the time of the May 2020 RFI publication, ANSI Z21.47-
2016 was the most up-to-date version of ANSI Z21.47. Since then, 
ANSI Z21.47-2021 was published.
---------------------------------------------------------------------------

    In the May 2020 RFI, DOE noted several differences between the 
industry standards currently incorporated by reference and the updated 
industry standards and sought comment on these changes. 85 FR 26626, 
26629-26631. Each change in the updated versions of

[[Page 10731]]

each standard and stakeholder comments in response to the May 2020 RFI 
are discussed in the following sections. DOE did not identify any 
substantive differences between the currently referenced industry 
standards and their updated versions that would pertain to the DOE test 
procedure for CWAFs, other than those discussed in the following 
sections. In response to the updates to the relevant industry 
standards, DOE is proposing to amend the Federal test procedure for 
CWAFs to incorporate by reference in 10 CFR part 431, subpart D, the 
following updated industry standards: UL 727-2018, AHRI 1500-2015, ANSI 
Z21.47-2021, and ANSI/ASHRAE 103-2017.
    As discussed, the DOE test procedure for CWAFs is specified in 10 
CFR 431.76. In this NOPR, DOE is proposing to establish appendix A to 
subpart D of 10 CFR part 431. DOE is reorganizing the CWAF setup and 
testing provisions currently proscribed in 10 CFR 431.76 into appendix 
A to clarify the test provisions that are necessary for determining 
thermal efficiency. DOE is reorganizing 10 CFR 431.76 in the way 
because, as discussed in section III.C of this document, DOE is also 
establishing appendix B for determining the proposed thermal efficiency 
two metric. DOE has tentatively determined that creating separate 
appendixes for the determination of the two different metrics would 
help clarify which appendix corresponds to which metric (i.e., appendix 
A is for thermal efficiency, while appendix B is for thermal efficiency 
two). Therefore, the establishment of appendix A is editorial and for 
reorganization purposes, and appendix A does not deviate from the 
current DOE test procedure unless specifically discussed in the 
sections below and in section III.E of this document.
1. UL 727-2006
    The CWAF test procedure at 10 CFR 431.76 requires use of those 
procedures contained in UL 727-2006 that are relevant to the steady-
state efficiency measurement (i.e., UL 727-2006 sections 1 through 3; 
37 through 42 (except for sections 40.4 and 40.6.2 through 40.6.7); 
43.2; and 44 through 46). In the May 2020 RFI, DOE identified two 
updates in UL 727-2018 relating to the scope and to thermocouple 
tolerance. 85 FR 26626, 26629-26630. In addition, since the publication 
of the May 2020 RFI, DOE has identified one additional update in UL 
727-2018 related to the definitions incorporated in section 3 of UL 
727-2018. These updates, the comments received from stakeholders 
regarding these updates, and DOE's proposal for each update are 
discussed in detail in the following sections. As previously mentioned 
in section III.B of this document, DOE is proposing to amend the DOE 
test procedure to incorporate by reference UL 727-2018.
a. Scope of UL 727
    In the May 2020 RFI, DOE noted that the language in section 1 of 
the UL 727-2018 test standard regarding the scope of the standard has 
been changed from that in UL 727-2006. 85 FR 26626, 26630. Section 1.3 
in UL 727-2006 references the NFPA ``Standard for Installation of Oil-
Burning Equipment,'' NFPA 31, and codes such as the ``Building 
Officials Code Administrators International National Mechanical Code,'' 
the ``State Building Code Council Standard Mechanical Code,'' and the 
``International Association of Plumbing and Mechanical Officials 
Uniform Mechanical Code'' for requirements for the installation and use 
of oil-burning equipment. In contrast, Section 1.3 of UL 727-2018 
references the NFPA ``Standard for Installation of Oil-Burning 
Equipment,'' NFPA 31, the ``International Mechanical Code,'' and the 
``Uniform Mechanical Code'' regarding installation and use of oil-
burning equipment.
    In the May 2020 RFI, DOE explained that DOE defines the scope for 
the testing of CWAFs in 10 CFR 431.76(a), and that the scope of 
applicability of the DOE test procedure is independent from the scope 
defined by UL-727-2006. 85 FR 26626, 26630. Although DOE references the 
scope of UL 727-2006 in its test provisions at 10 CFR 431.76(c)(2), 
only the procedures within UL 727-2006 that are pertinent to the 
measurement of the steady-state efficiency are included in the DOE test 
procedure. 10 CFR 431.76(b). Therefore, any provisions within the scope 
of UL 727-2006 that do not relate to the measurement of the steady-
state efficiency do not apply to the DOE test procedure.
    In the May 2020 RFI, DOE sought comment on whether there is a need 
to identify more specifically the provisions of UL 727-2006 that apply 
to the DOE test procedure. Id. In response, AHRI recommended the 
adoption of the most current edition of UL 727 published in 2018 and 
stated that it does not believe there is a need to identify provisions 
from the 2006 edition in the DOE test procedure. (AHRI, No. 7 at p. 3)
    DOE has tentatively determined that the scope section of UL 727-
2018 is inapplicable to the DOE test procedure because the scope of the 
DOE test procedure is defined separately in 10 CFR 431.76(a), and only 
the provisions in UL 727-2018 that relate to the measurement of steady-
state efficiency apply to the DOE test procedure. While DOE is 
proposing to incorporate by reference UL 727-2018 in its entirety, DOE 
is proposing to explicitly identify the provisions of UL 727-2018 that 
are applicable to the DOE test procedure for CWAF, which would not 
include the scope section of that industry standard, since the scope of 
the DOE test procedure is defined separately in 10 CFR 431.76(a).
b. Thermocouple Tolerance
    The DOE test procedure currently incorporates Section 40 of UL 727-
2006 for the test set-up for oil-fired commercial warm air furnaces. 10 
CFR 431.76(c)(2). In the May 2020 RFI, DOE noted that Section 40.6.1 of 
UL 727-2018, which pertains to temperature measurements using 
potentiometers and thermocouples, has different language from UL 727-
2006 and incorporates different ANSI references. 85 FR 26626, 26629-
26630. Specifically, UL 727-2006 specifies that the thermocouple wire 
must conform to the requirements specified in the Initial Calibration 
Tolerances for Thermocouples table (i.e., Table 8) in International 
Society of Automation (``ISA'') standard MC96.1, ``Temperature-
Measurement Thermocouples'' (``ANSI/ISA MC96.1''). In contrast, UL 727-
2018 states that the thermocouple wire must conform to the requirements 
specified in the Tolerance on Initial Values of Electromagnetic Force 
(``EMF'') Versus Temperature tables (i.e., Tables 1-3) in ANSI/ASTM 
E230/E230M-17 ``Standard Specification for Temperature-Electromotive 
Force (emf) Tables for Standardized Thermocouples,'' (``ASTM E230/
E230M-17''). The thermocouple specifications in ANSI/ISA MC96.1 and 
ANSI/ASTM E230/E230M-17 are applicable only to the range of 
temperatures associated with the types of thermocouples specified in 
each of the industry standards. As discussed in the May 2020 RFI, based 
on an initial review of ANSI/ASTM E230/E230M-17, the temperature ranges 
to which the ANSI/ASTM E230/E230M-17 specifications apply differ from 
the temperature ranges specified in MC96.1 for certain thermocouple 
wires. Specifically, ANSI/ASTM E230/E230M-17 includes temperature 
ranges and specifications for thermocouple types C, N, and mineral-
insulated metal-sheathed E type, which are not included in ANSI/ISA 
MC96.1; and tolerances on initial values of EMF versus temperature for 
extension wires and compensating extension wires in ANSI/ASTM E230/

[[Page 10732]]

E230M-17 (i.e., Tables 2 and 3) have been added to Section 40.6.1 of UL 
727-2018. Id. at 85 FR 26630.
    In the May 2020 RFI, DOE asked for comment regarding the changes 
resulting from UL 727-2018 referencing ANSI/ASTM E230/E230M-17. 
Specifically, DOE asked for comment on whether the additional 
references and changes to the thermocouple and thermocouple extension 
wire requirements would impact the representativeness of the measured 
test results or test burden of the DOE CWAF test procedure, if adopted. 
Id. DOE also sought comment on why Section 40.6.1 in UL 727 was changed 
from referencing ANSI/ISA MC96.1 in UL 727-2006, to ANSI/ASTM E230/
E230M in UL 727-2018. DOE requested input on the perceived benefits 
and/or drawbacks of such change. 85 FR 26626, 26630.
    AHRI encouraged DOE to evaluate how any additions or changes to the 
thermocouple and thermocouple extension wire requirements to determine 
the full impact any differences may have on current products' ability 
to remain compliant. (AHRI, No. 7 at p. 2) AHRI also commented that 
ANSI/ISA MC96.1 is an obsolete standard that was last published in 1982 
and was administratively withdrawn by ISA in 2011. Additionally, AHRI 
stated that the ANSI/ASTM E230/E230M-17 standard represents current 
technologies and is maintained on a periodic basis in accordance with 
the ASTM standards development procedures. (AHRI, No. 7 at pp. 2-3)
    DOE has confirmed that ANSI/ISA MC96.1 was administratively 
withdrawn by ISA. As the ANSI/ASTM E230/E230M-17 standard is the 
current industry standard regarding thermocouples, it is expected that 
thermocouples currently being used for testing meet the specifications 
of that industry standard. Furthermore, DOE notes that the requirements 
in ANSI/ASTM E230/E230M-17 allow additional thermocouple wires for 
testing, in addition to those that were specified in ANSI/ISA MC96.1. 
Therefore, DOE expects units tested according to the previous 
requirements in ANSI/ISA MC96.1 would subsequently meet those in ANSI/
ASTM E230/E230M-17. DOE received no additional comments on this topic. 
Absent data and information to indicate that the requirements in ANSI/
ASTM E230/E230M-17 are not appropriate or result in a significant 
change from the provisions in ANSI/ISA MC96.1. DOE has tentatively 
determined that there is not sufficient evidence to indicate ANSI/
ASTME230/E230M-17 would not meet the requirements in 42 U.S.C. 
6314(a)(2) and (3), related to representative use and test burden. 
Additionally, if DOE were to continue to reference a test procedure 
that is administratively withdrawn, industry may find it difficult to 
obtain copies of the obsolete standard. Therefore, DOE is proposing to 
incorporate the ANSI/ASTM E230/E230M-17 thermocouple provisions 
referenced in UL 727-2018 (i.e., Tables 1-3 of ANSI/ASTM E230/E230M-17) 
in the DOE test procedure for CWAFs.
c. NFPA 97-2003
    Sections 3.11 and 3.27 of UL 727-2018 state that the definitions of 
terms ``combustible'' and ``noncombustible'' are the definitions found 
within NFPA 97M, ``Standard Glossary of Terms Relating to Chimneys, Gas 
Vents and Heat Producing Appliances'' (``NFPA 97M''). UL 727-2018 does 
not specify which version of NFPA 97M is being referenced in the 
standard, nor does it include a publication date of version number of 
the NFPA 97M standard. The latest version of NFPA 97M of which DOE is 
aware is a version published in 1967. DOE also notes that NFPA's 
website does not contain a NFPA 97M publication, and instead contains 
NFPA 97-2003 ``Standard Glossary of Terms Relating to Chimneys, Vents, 
and Heat-Producing Appliances'' (NFPA 97-2003). NFPA 97-2003 contains 
definitions for ``combustible material'' and ``noncombustible 
material,'' however NFPA 97M only contains a definition for 
``combustible material.'' DOE notes that there are minor differences 
between the definitions for ``combustible material'' in both standards, 
and that DOE tentatively concludes that there are no substantial 
differences.\7\ Further, DOE has tentatively concluded that UL 727-2018 
references an outdated standard (NFPA 97M) and should instead reference 
the most up-to-date industry standard (NFPA 97-2003). Therefore, DOE is 
proposing to incorporate by reference NFPA 97-2003, and is proposing 
that the references to NFPA 97M that are relevant to the DOE test 
procedure (i.e., those made within Sections 3.11 and 3.27 of UL 727-
2018) shall instead reference NFPA 97-2003.
---------------------------------------------------------------------------

    \7\ NFPA 97-2003 defines ``combustible material'' as ``material 
made of or surfaced with wood, compressed paper, plant fiber, 
plastics, or other material that can ignite and burn, whether 
flameproofed or not, or whether plastered or unplastered.'' (Section 
3.3.44 of NFPA 97-2003) NFPA 97M defines ``combustible material'' as 
``combustible material, as pertaining to materials adjacent to or in 
contact with heat-producing appliances, chimney connectors and vent 
connectors, steam and hot-water pipes, and warm-air ducts, means 
material made of or surfaced with wood, compressed paper, plant 
fibers, or other materials that will ignite and burn. Such material 
shall be considered as combustible even though flameproofed, fire-
retardant treated, or plastered.'' (NFPA 97M, part II, p. 193)
---------------------------------------------------------------------------

    DOE seeks comment on its tentative conclusion that NFPA 97M is an 
outdated standard that has been superseded by NFPA 97-2003. DOE seeks 
comment on its proposal to incorporate by reference NFPA 97-2003 in 10 
CFR part 431, subpart D.
2. HI BTS-2000
    DOE's test procedure for oil-fired CWAFs references sections of HI 
BTS-2000 that are relevant to fuel oil analysis and calculating percent 
flue loss (i.e., HI BTS-2000 sections 8.2.2, 11.1.4, 11.1.5, and 
11.1.6.2). 10 CFR 431.76(c)(2) and (e)(2). DOE's test procedure 
includes these provisions because DOE has previously determined that UL 
727 does not provide a procedure for calculating the percent flue loss 
of the furnace, which is necessary in calculating the thermal 
efficiency (``TE''), and therefore incorporated by reference provisions 
from HI BTS-2000 to calculate the flue loss for oil-fired CWAFs. 69 FR 
61916, 61917, 61940.
    In 2015, HI BTS-2000 was redesignated by AHRI as AHRI 1500-2015. In 
the May 2020 RFI, DOE identified two substantive changes in the 
sections relevant to the DOE test procedure in the update from HI BTS-
2000 to AHRI 1500-2015 regarding fuel oil analysis and calculation of 
flue loss. 85 FR 26626, 26630. DOE requested comment generally 
regarding whether any of the differences between Sections 8.2.2, 
11.1.4, 11.1.5, and 11.1.6.2 of HI BTS-2000 and AHRI 1500-2015 are 
relevant to the DOE test procedure, and if so, how such differences 
would impact the representativeness of measurements and the associated 
test burden of the DOE commercial warm air furnaces test procedure, if 
adopted. Id. at 85 FR 26631. The updates to AHRI 1500-2015, the 
comments received from stakeholders regarding these updates, and DOE's 
proposal for each update are discussed in detail in the following 
paragraphs. As previously mentioned in section III.B of this document, 
DOE is proposing to amend the DOE test procedure to incorporate by 
reference AHRI 1500-2015.
a. Fuel Oil Analysis Requirements
    DOE's test procedure for oil-fired CWAFs includes fuel oil analysis 
requirements that reference Section 8.2.2 of HI BTS-2000. 10 CFR 
431.76(c)(2). As noted in the May 2020 RFI, Section C3.2.1.1 of AHRI 
1500-2015 (previously Section 8.2.2 of HI BTS-2000) specifies different 
fuel oil

[[Page 10733]]

analysis requirements (i.e., heating value analyzed per ASTM D240-09 
\8\ or ASTM D4809-09a,\9\ hydrogen and carbon content analyzed per ASTM 
D5291-10,\10\ and density and American Petroleum Institute (``API'') 
gravity analyzed per ASTM D396-14a \11\) than are required in Section 
8.2.2 of HI BTS-2000 (i.e., heat value, hydrogen and carbon content, 
density and API gravity analyzed per ASTM D396-90 \12\). 85 FR 26626, 
26631.
---------------------------------------------------------------------------

    \8\ ASTM D240-09 ``Standard Test Method for Heat of Combustion 
of Liquid Hydrocarbon Fuels by Bomb Calorimeter'' (``ASTM D240-
09'').
    \9\ ASTM D4809-09a ``Standard Test Method for Heat of Combustion 
of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)'' 
(``ASTM D4809-09a'').
    \10\ ASTM D5291-10 ``Standard Test Methods for Instrumental 
Determination of Carbon, Hydrogen, and Nitrogen in Petroleum 
Products and Lubricants'' (``ASTM D5291-10'').
    \11\ ASTM D396-14a ``Standard Specification for Fuel Oils'' 
(``ASTM D396-14a'').
    \12\ ASTM D396-90 ``Standard Specification for Fuel Oils'' 
(``ASTM D396-90'').
---------------------------------------------------------------------------

    In the May 2020 RFI, DOE asked for comment regarding the 
differences between the fuel oil analysis requirements in each 
standard, whether the differences between the two would yield different 
results during testing, and whether adopting AHRI 1500-2015 would add 
or reduce burden to the current testing requirements of the DOE test 
procedure. 85 FR 26626, 26631.
    The CA IOUs encouraged DOE to ensure that fuel oil analysis 
requirements are consistent across applicable test procedures. (CA 
IOUs, No. 8 at p. 4) AHRI stated that the two standards show no 
significant changes and that adoption of AHRI 1500-2015 would not yield 
different results during testing. AHRI reiterated its support for the 
adoption of the most current edition of this standard, stating that 
this edition represents the most current technology and information 
available at the time of publication, and that HI BTS-2000 is an 
obsolete standard no longer maintained by AHRI. Furthermore, AHRI 
stated that it has determined that there is no change in the burden by 
adopting AHRI 1500-2015. (AHRI, No. 7 at p. 4)
    DOE has not received any information or data indicating that 
updating the HI BTS-2000 reference to AHRI 1500-2015 would result in a 
test procedure that would not meet the representativeness requirements 
or be unduly burdensome to conduct. DOE has confirmed that HI BTS-2000 
is no longer maintained by AHRI and has tentatively determined that it 
is an obsolete standard. AHRI 1500-2015 represents the industry's most 
up to date requirements for fuel oil analysis, and no issues or 
differences between the new and old standards that would impact results 
or require retesting have been reported to DOE. Because of this, and 
based on stakeholder comment, DOE has tentatively determined that 
incorporating AHRI 1500-2015 into the DOE test procedure would not 
impact the performance of a CWAF under test or require CWAFs to be 
retested. Additionally, if DOE were to continue to reference a test 
procedure that is administratively withdrawn, industry may find it 
difficult to obtain copies of the obsolete standard. Therefore, DOE has 
tentatively determined that AHRI 1500-2015, the successor industry 
standard to the currently referenced HI BTS-2000, contains fuel oil 
analysis requirements that are equivalent to the requirements in HI 
BTS-2000 and are currently being used by test facilities. Therefore, 
DOE is proposing to incorporate by reference AHRI 1500-2015, including 
its fuel oil analysis specifications.
b. Calculation of Carbon Dioxide in Flue Gas Losses
    In the May 2020 RFI, DOE noted that Section 11.1.4 of HI BTS-2000 
requires that the carbon dioxide (``CO<INF>2</INF>'') value used in the 
calculation of the dry flue gas loss for oil must be the measured 
CO<INF>2</INF>. 85 FR 26626, 26631. Section C7.2.4 of AHRI 1500-2015 
(previously Section 11.1.4 in HI BTS-2000) includes the option to 
calculate CO<INF>2</INF> using the measured oxygen (``O<INF>2</INF>'') 
value instead of directly measuring the CO<INF>2</INF> value. The DOE 
test procedure at 10 CFR 431.76(d) requires that CO<INF>2</INF> must be 
measured.
    In the May 2020 RFI, DOE asked for comment on whether the option to 
calculate CO<INF>2</INF> in AHRI 1500-2015 yields different testing 
results compared to using the measured value, and whether it should 
adopt the AHRI 1500-2015 provisions that allow for measuring 
O<INF>2</INF> and calculating CO<INF>2</INF>. Id. The CA IOUs stated 
that measuring CO<INF>2</INF> levels is more accurate than calculating 
CO<INF>2</INF> levels based on O<INF>2</INF> measurements. The CA IOUs 
also stated that since certified labs and manufacturers are already 
equipped to measure CO<INF>2,</INF> DOE should maintain the current 
requirement for direct CO<INF>2</INF> measurements. (CA IOUs, No. 8 at 
p. 4) AHRI recommended that the option to calculate CO<INF>2</INF> 
based on a measurement of O<INF>2</INF> be added to the DOE test 
method. AHRI stated that using a calculated CO<INF>2</INF> yields 
comparable results and is equivalent using a measured CO<INF>2</INF> 
value. (AHRI, No. 7 at p. 4)
    DOE has identified O<INF>2</INF> sensors on the market that are 
accurate to within <plus-minus>0.1 percent, which is equivalent to or 
greater than the accuracy of the CO<INF>2</INF> sensors used in labs 
that perform CWAF testing. Therefore, if such O<INF>2</INF> sensors are 
used to measure O<INF>2</INF> as a means for calculating 
CO<INF>2</INF>, the value of CO<INF>2</INF> obtained through 
calculation and the value obtained through direct measurement should be 
comparable. DOE also consulted with independent third-party testing 
facilities and found that some of these facilities currently use 
sensors that measure O<INF>2</INF> in the flue gasses and perform an 
internal calculation to determine CO<INF>2</INF> in the flue gasses. In 
addition, AHRI 1500-2015 includes the option to directly measure 
CO<INF>2</INF>, so if that option is less burdensome, test facilities 
would continue to be able to rely on it. DOE has tentatively determined 
that calculating CO<INF>2</INF> using a measured O<INF>2</INF> value, 
as specified in AHRI 1500-2015, would provide results equivalent to the 
CO<INF>2</INF> measurement currently required by the DOE test method, 
and that allowing a calculated value of CO<INF>2</INF> would harmonize 
with the latest industry standard without increasing test burden. For 
these reasons, DOE proposes to incorporate by reference the provisions 
in AHRI 1500-2015 that provide an optional procedure for measuring 
CO<INF>2</INF> based on measured O<INF>2</INF> values. DOE also 
proposes to establish section 3 of appendix A (i.e., an update of 10 
CFR 431.76(d) of the current DOE test procedure) to reflect DOE's 
proposal to allow measuring O<INF>2</INF>, and this includes requiring 
that O<INF>2</INF> measurements are determined with an instrument that 
has a reading error no greater than <plus-minus>0.1 percent. DOE notes 
that Table C1 of AHRI 1500-2017 specifies that O<INF>2</INF> shall be 
measured with an accuracy no greater than <plus-minus>0.1 percent, and 
therefore this proposal aligns with the requirements in the industry 
standard.
    DOE seeks comment on its proposal to adopt the optional method 
specified in AHRI 1500-2015 that allows for calculating CO<INF>2</INF> 
using a measured O<INF>2</INF> value. DOE also seeks comment on its 
proposal to establish section 3 of appendix A (i.e., an update of 10 
CFR 431.76(d) of the current DOE test procedure) to accommodate the 
option to calculate CO<INF>2</INF> using a measured O<INF>2</INF> 
value.
3. ANSI Z21.47
    In the May 2020 RFI, DOE noted that the test method in 10 CFR 
431.76 for gas-fired CWAFs requires the use of procedures contained in 
ANSI Z21.47-2012 that are relevant to the steady-state efficiency 
measurement (i.e., Sections 1.1, 2.1 through 2.6, 2.39, and 4.2.1 of 
ANSI Z21.47-2012). 81 FR 26626, 26630. DOE noted that the majority of 
the test standard provisions relevant to

[[Page 10734]]

DOE's test procedure did not change in the most up-to-date version of 
the industry standard at that time, ANSI Z21.47-2016. Id. The revisions 
that were made were mostly editorial in nature, including moving 
Section 2 in ANSI Z21.47-2012 to Section 5 in ANSI Z21.47-2016, among 
other structural changes. In reviewing the 2012 and 2016 versions of 
the standard, DOE identified one apparent typographical error in the 
2016 version.
    Since the publication of the May 2020 RFI, an updated version of 
the ANSI Z21.47 standard was published in 2021: ANSI Z21.47-2021. DOE 
notes that the only substantive difference between the 2016 and 2021 
versions relevant to the sections referenced by the DOE test procedure 
is related to burner operating characteristics tests specified in 
Section 5.4a of both ANSI Z21.47-2016 and ANSI Z21.47-2021.
    The updates to ANSI Z21.47-2012 in ANSI Z21.47-2016 and ANSI 
Z21.47-2021, as well as the scope of the industry standard, are 
discussed in further detail in the following sections. As previously 
mentioned in section III.B of this document, DOE is proposing to amend 
the DOE test procedure to reference ANSI Z21.47-2021, as it is the most 
recent version of the industry test procedure.
a. Scope of ANSI Z21.47
    DOE's test procedure for CWAFs currently includes reference to the 
scope Section (section 1.1) of ANSI Z21.47-2012. 10 CFR 431.76(c). As 
previously stated in section III.B.1.a of this document, DOE defines 
the scope for the testing of CWAFs in 10 CFR 431.76(a), and DOE's test 
procedure for CWAFs requires use of ANSI Z21.47 only for provisions 
pertinent to the measurement of the steady-state efficiency.
    While DOE is proposing to incorporate by reference ANSI Z21.47-2021 
in its entirety, DOE is proposing to explicitly identify the provisions 
of ANSI Z21.47-2021 that are applicable to the DOE test procedure for 
CWAFs, which would not include the scope section of that industry 
standard.
b. Typographical Error
    Section 2.3.2(c) of ANSI Z21.47-2012 and the corresponding Section 
5.3.2(c) of ANSI Z21.47-2021 provide installation requirements for 
horizontal furnaces. In the May 2020 RFI, DOE noted that Section 
5.3.2(c)(iii) of ANSI Z21.47-2016 appears to contain a typographical 
error by referencing ``Figure 4, Enclosure types for alcove and closet 
installation tests for horizontal furnaces.'' 85 FR 26626, 26630. The 
title of Figure 4 in ANSI Z21.47-2016 is ``Enclosure types for alcove 
and closet installation tests for up-flow and down-flow furnaces,'' and 
as titled, Figure 4 applies only to up-flow and down-flow furnaces. It 
appears that the appropriate reference in Section 5.3.2(c)(iii) of ANSI 
Z21.47-2016 should be to Figure 5, ``Enclosed types for alcove and 
closet installation tests for horizontal furnaces.''
    In the May 2020 RFI, DOE asked for comment on whether Section 
5.3.2(c)(iii) of ANSI Z21.47-2016 should refer to Figure 5 in the test 
procedure, rather than Figure 4. Id. AHRI, Trane, and Carrier all 
agreed that the reference to Figure 4 was a typographical error, and 
that Section 5.3.2(c)(iii) of ANSI Z21.47-2016 should refer to Figure 
5. (AHRI, No. 7 at p. 3; Trane, No. 9 at p. 2; Carrier, No. 4 at p. 1)
    In the update to the industry standard, ANSI Z21.47-2021 corrected 
this typographical error by having Section 5.3.2(c)(iii) reference 
Figure 5. Therefore, the typographical error in ANSI Z21.47-2016 is no 
longer relevant because DOE is now proposing to incorporate by 
reference ANSI Z21.47-2021.
c. Propane Nomenclature
    DOE also asked for comment regarding any differences between ANSI 
Z21.47-2012 and ANSI Z21.47-2016, and specifically whether there are 
any differences other than those already identified by DOE in the May 
2020 RFI. Id. In response to DOE's request for comment regarding any 
additional differences between ANSI Z21.47-2012 and ANSI Z21.47-2016, 
AHRI and Trane both noted that in ANSI Z21.47-2016, the term 
``propane'' is used in place of the term ``liquified petroleum gas;'' 
however, the commenters stated that this change is not substantive.\13\ 
(AHRI, No. 7 at p. 3; Trane, No. 9 at p. 2) Carrier did not 
specifically comment on this nomenclature change, although it stated 
that there are no additional updates in AHRI Z21.47-2016 that would 
impact the DOE test procedure, other than those already identified by 
DOE. (Carrier, No. 4 at p. 1)
---------------------------------------------------------------------------

    \13\ Trane stated that ANSI Z21.47-2016 uses the term 
``propane'' in place of the term ``liquified natural gas''. (Trane, 
No. 9 at p. 2) However, DOE notes that ANSI Z21.47-2012 uses the 
term ``liquified petroleum gas,'' not ``liquified natural gas,'' and 
believes this was what Trane intended to note.
---------------------------------------------------------------------------

    DOE notes that ANSI Z21.47-2021 also uses the term ``propane'' in 
place of ``liquified petroleum gas.'' DOE tentatively agrees with AHRI 
and Trane that the use of ``propane'' instead of ``liquified petroleum 
gas'' is for clarification only, and, therefore, does not affect the 
test procedure. Therefore, DOE is proposing to incorporate by reference 
ASNI Z21.47-2021 and specify use of the sections that correspond to the 
sections currently referenced in the DOE test procedure (i.e., Sections 
5.1 through 5.6, 5.40, and 7.2.1 of ANSI Z21.47-2021),), including the 
language referring to ``propane'' instead of ``liquefied petroleum 
gas.''
d. Burner Operating Characteristics Tests
    Section 2.4a of ANSI Z21.47-2012 is referenced in the current DOE 
test procedure for CWAFs. 10 CFR 431.76(c)(2). This section states that 
three separate tests (each specified in Sections 2.9.1(a), 2.10.1, and 
2.11.3, respectively, of ANSI Z21.47-2012) shall be performed prior to 
the performance test to ensure that there is no burner flashback and 
that the ignition system is working properly. Section 2.4a states that 
these three burner operating characteristics tests shall be conducted 
with test gas G (i.e., butane-air). ANSI Z21.47-2021 includes a minor 
alteration to these provisions, which allows for performing these tests 
with a different test gas. Section 5.4a of ANSI Z21.47-2021 (previously 
section 2.4a in ANSI Z21.47-2012) states that the burner operating 
characteristics tests shall be performed with either test gas G or, at 
the manufacturer's option for testing premixed burners, test gas H 
(i.e., propane-air). DOE notes that the burner operating 
characteristics tests, including the test gas used for these tests, do 
not affect the TE measurement of a CWAF. Therefore, DOE does not have 
evidence to deviate from the industry test procedure and proposes to 
adopt Section 5.4 of ANSI Z21.47-2021, including the previsions 
regarding the use of test gas as an option when performing the burner 
characteristics tests.
    DOE seeks comment on whether the option provided in Section 5.4a of 
ANSI Z21.47-2021 to use test gas H when performing the three burner 
characteristics tests would impact the representativeness or burden of 
the thermal efficiency test.
4. ANSI/ASHRAE 103
    In the May 2020 RFI, DOE noted that DOE's test procedure for gas-
fired condensing CWAFs references Sections 7.2.2.4, 7.8, 9.2, 11.3.7.1 
and 11.3.7.2 of ANSI/ASHRAE Standard 103-2007. 10 CFR 431.76; 85 FR 
26626, 26630. DOE did not identify any substantive changes in the 
sections currently referenced by the DOE test procedure in the update 
from ANSI/ASHRAE 103-2007 to ANSI/

[[Page 10735]]

ASHRAE 103-2017; however, DOE asked for comment on whether there were 
any differences between the two standards that are relevant to the DOE 
test procedure, and if so, how such differences would impact the 
representativeness of measurements and the test burden of the DOE test 
procedure for CWAFs, if adopted. Id.
    AHRI commented that Sections 11.3.7.1 and 11.3.7.2 in ANSI/ASHRAE 
103-2017 were modified to replace a fixed numerical value with 
mathematical expressions, but that there were no significant changes to 
the clauses specified in the DOE test procedure. (AHRI, No. 7 at p. 3) 
Trane stated that equations were modified only in terms from numeric to 
mathematical, but that this did not change the outcomes of the 
measurements. (Trane, No. 9 at p. 2)
    DOE acknowledges that the two equations in Sections 11.3.7.1 and 
11.3.7.2 of ANSI/ASHRAE 103-2017 have been modified. ANSI/ASHRAE 103-
2007 includes variables in each equation that are defined as constants 
in the list of variables below each equation (e.g., latent heat of 
vaporization equals 1053.3 Btu per pound mass (``Btu/lbm'')); in 
contrast, ANSI/ASHRAE 103-2017 inserts the constants directly into each 
equation. DOE has tentatively determined that the changes to the 
equations referenced by DOE (specifically those in clauses 11.3.7.1 and 
11.3.7.2 of ANSI/ASHRAE 103-2017) are editorial in nature and do not 
change the calculated values. As previously mentioned in section III.B 
of this document, DOE is proposing to amend the DOE test procedure to 
reference ANSI/ASHRAE 103-2017, which would include these changes.

C. ``Thermal Efficiency Two'' Metric

    As previously discussed, EPCA requires that the test procedures for 
CWAFs be those generally accepted industry testing procedures or rating 
procedures developed or recognized by AHRI or ASHRAE, as referenced in 
ASHRAE Standard 90.1. (42 U.S.C. 6314(a)(4)(A)) If such an industry 
test procedure or rating procedure is amended, the Secretary shall 
amend the test procedure for the product as necessary to be consistent 
with the amended industry test procedure or rating procedure unless the 
Secretary determines, by rule, published in the Federal Register and 
supported by clear and convincing evidence, that to do so would not 
meet the requirements in 42 U.S.C. 6314(a)(2) and (3) related to 
representative use and test burden.\14\ (42 U.S.C. 6314(a)(4)(B))
---------------------------------------------------------------------------

    \14\ 42 U.S.C. 6314(a)(2) requires that test procedures be 
reasonably designed to produce test results which reflect energy 
efficiency, energy use, and estimated operating costs of a type of 
industrial equipment (or class thereof) during a representative 
average use cycle (as determined by the Secretary), and shall not be 
unduly burdensome to conduct. 42 U.S.C. 6314(a)(3) requires that if 
the test procedure is a procedure for determining estimated annual 
operating costs, such procedure shall provide that such costs shall 
be calculated from measurements of energy use in a representative 
average-use cycle (as determined by the Secretary), and from 
representative average unit costs of the energy needed to operate 
such equipment during such cycle.
---------------------------------------------------------------------------

    As discussed in further detail in the sub-sections that immediately 
follow, DOE has tentatively determined that a test procedure that 
includes jacket loss and accounts for part-load operation would better 
produce test results that reflect energy efficiency, energy use, and 
estimated operating costs of CWAFs during a representative average use 
cycle. CWAFs are typically installed outdoors and as a result jacket 
losses can be a significant source of energy loss. Further, for models 
with multiple heating stages, performance can vary at the maximum input 
heating stage as compared to reduced input stage(s). Therefore, DOE is 
proposing to account for these factors by establishing a new test 
procedure and metric for CWAFs, termed ``Thermal Efficiency Two'' 
(``TE2''), which would generally adopt the same changes proposed for 
the current test procedure at appendix A, but would additionally 
account for jacket losses and part load operation. The proposed TE2 
test procedure would account for flue losses in the same manner as the 
current TE metric. DOE proposes to establish a new appendix B to 10 CFR 
part 431, which would contain the test method for TE2.
    If adopted, manufacturers would be permitted to make voluntary 
representations using TE2. Mandatory use of the TE2 test procedure 
would be required at such time as compliance is required with amended 
energy conservation standards based on TE2, should DOE adopt such 
standards. DOE is, therefore, also proposing to retain the test method 
for TE, which is proposed to be modified as discussed elsewhere in this 
document, in appendix A for use until such time as TE2 becomes 
mandatory.
    DOE seeks comment on its proposal to establish a new test procedure 
(i.e., appendix B) and metric (i.e., TE2) for CWAFs, which would 
generally adopt the same changes proposed for the current test 
procedure at appendix A and account for flue losses in the same manner 
as the current TE metric, but would additionally account for jacket 
losses and part load operation.
1. Jacket Loss
    As discussed, the current energy efficiency metric for CWAFs is TE. 
10 CFR 431.77. TE for a CWAF is defined in 10 CFR 431.72 as 100 percent 
minus the percent flue loss, and is calculated, as specified in 10 CFR 
431.76(e), by following the procedure specified in Section 2.39 of ANSI 
Z21.47-2012 for gas-fired CWAFs and Sections 11.1.4, 11.1.5, and 
11.1.6.2 of HI BTS-2000 for oil-fired CWAFs.\15\ A test method and 
calculations for determining the jacket loss percentage (i.e., the 
hourly heat loss through the jacket divided by the hourly input and 
multiplied by 100) are included in Section 2.39 of ANSI Z21.47-2012 
(and the corresponding Section 5.40 of ANSI Z21.47-2021), which is 
referenced in the DOE test procedure. However, the jacket loss 
percentage is not included in the equation used to calculate TE.\16\
---------------------------------------------------------------------------

    \15\ 10 CFR 431.76(f) (i.e., section 5 of appendix A) includes a 
TE adjustment for condensing CWAFs. This adjustment adds the 
additional heat gain (expressed in a percent) from condensation of 
water vapor to the TE and subtracts the heat loss (expressed as a 
percent) due to the flue condensate flowing down the drain.
    \16\ DOE notes that Section 2.39 of ANSI Z21.47-2012 and Section 
5.40 of ANSI Z21.47-2021 specify a maximum jacket loss of 1.5 
percent for any furnace not covered by ``Federal Energy Acts'' 
(i.e., not regulated by DOE). This provision is not referenced as 
part of the DOE test procedure.
---------------------------------------------------------------------------

    In the May 2020 RFI, DOE requested comment on whether jacket loss 
should be accounted for in the calculation of TE. Specifically, DOE 
asked for comment regarding information and data on whether and to what 
extent inclusion of jacket loss would provide results that would more 
appropriately reflect energy efficiency during a representative average 
use cycle, and also information and data as to the test burden that 
would be associated with potential inclusion of jacket loss as part of 
the DOE CWAF test procedure. Id
    ASAP, NEEA,\17\ and the CA IOUs each supported adding jacket loss 
to the TE metric, stating that jacket loss could have a large impact on 
overall thermal efficiency. (ASAP, No. 5 at p.1; NEEA, No. 10 at p.3; 
CA IOUs, No. 8 at p.4) Specifically, the CA IOUs stated that furnace 
jacket losses have significant variations based on the installation 
configuration (e.g., stand-alone vs. embedded in a commercial unitary 
air-conditioner (``CUAC'')) and the mode of operation used for testing 
(e.g., full-load

[[Page 10736]]

vs. part-load), and suggested that DOE consider using the method in 
ASHRAE 155P for determining commercial boiler jacket loss for CWAFs, if 
this method is repeatable and reproducible. (CA IOUs, No. 8 at p. 4) 
NEEA stated that its energy modeling showed that improved insulation, 
decreased casing leakage, and decreased damper leakage can save up to 
11 percent of annual energy consumption, and that this magnitude of 
energy savings is comparable with that of a condensing secondary heat 
exchanger, which is listed as ``max tech'' in the current CWAF energy 
conservation standards rulemaking. NEEA also stated that although CWAFs 
are separately regulated from CUACs, the two types of equipment are 
often contained within the same rooftop unit (``RTU''), and that 
enclosure improvements that would improve efficiency of CWAFs would 
also improve efficiency for CUACs. (NEEA, No. 10 at pp. 3-4) ASAP 
stated that since the impact of improved insulation is not currently 
considered in the test procedure, two CWAF units could have the same 
efficiency rating and yet provide significantly different performance 
if one unit had better insulation than the other. ASAP further 
explained that capturing the impact of improved insulation would 
provide testing results that would better reflect the efficiency of 
CWAFs during a representative average use cycle, and, in turn, provide 
better information to purchasers. (ASAP, No. 5 at p. 1)
---------------------------------------------------------------------------

    \17\ DOE also received comment from NEEA supporting the addition 
of jacket loss to the TE metric in response to the May 2020 ECS RFI. 
(NEEA, EERE-2019-BT-STD-0042-0024 at pp. 6-7)
---------------------------------------------------------------------------

    AHRI, Carrier,\18\ and Trane opposed incorporating jacket loss into 
the TE metric and asserted that it would have a minimal effect on 
performance. (AHRI, No. 7 at p. 5; Carrier, No. 4 at pp. 1-2; Trane, 
No. 9 at p. 3) AHRI and Trane stated that including jacket loss in the 
TE calculation would result in minimal change in TE and would lower the 
TE of the CWAF. (AHRI, No. 7 at p. 5 Trane, No. 9 at p. 3) Carrier also 
stated that for larger commercial equipment, factory installed options 
are available that can increase the size of the cabinet downstream of 
the furnace section, and that test burden on manufacturers would 
increase significantly if all options that impact jacket size are 
required to be tested. Carrier asserted that DOE would have to 
demonstrate the energy benefit since jacket losses are relatively low 
and their inclusion would result in increased test burden, different 
design requirements, and significantly higher cost for the manufacturer 
and the end customer if the minimum efficiency standards did not 
materially change. (Carrier, No. 4 at p. 2)
---------------------------------------------------------------------------

    \18\ DOE also received comment from Carrier opposing this in 
response to the May 2020 ECS RFI, similarly, stating that jacket 
loss would have a minimal effect on performance, and that this 
minimal affect does not justify its inclusion the TE. (Carrier, 
EERE-2019-BT-STD-0042-0013 at p. 5)
---------------------------------------------------------------------------

    On May 12, 2020, DOE published an energy conservation standards RFI 
(``May 2020 ECS RFI'') for air-cooled CUACs, commercial unitary heat 
pumps, and CWAFs. 85 FR 27941. DOE received multiple comments from 
stakeholders in response to the May 2020 ECS RFI that are related to 
jacket loss and that are relevant to DOE's consideration of whether to 
incorporate jacket losses into the test procedure for CWAFs. 
Specifically, the Joint Advocates recommended that DOE amend the CWAF 
test procedure to include effects of improved insulation.\19\ (Joint 
Advocates, EERE-2019-BT-STD-0042-0023 at p. 3) AHRI stated that it does 
not see a justification to include jacket loss in the measured energy 
efficiency, and that there would be minimal, if any, change in the 
usable heat provided to the end user if jacket loss is added to the TE 
calculation. (AHRI, EERE-2019-BT-STD-0042-0014 at p. 4) Goodman stated 
that jacket losses should not be included in the CWAF test procedure, 
and that inclusion of jacket loss would require new and more difficult 
testing and increased burden. (Goodman, EERE-2019-BT-STD-0042-0017 at 
pp. 2-3) Lastly, Goodman recommended DOE not include jacket loss in the 
DOE test procedure because ASHRAE 90.1-2019 requires that CWAF jacket 
loss not exceed 0.75 percent of the CWAF input rating, and therefore 
any effect on measured performance would be small enough to not justify 
the added burden. Id.
---------------------------------------------------------------------------

    \19\ The Join Advocates include the following organizations: 
Appliance Standards Awareness Project, American Council for an 
Energy Efficient Economy, California Energy Commission, Natural 
Resources Defense Council, and Northeast Energy Efficiency 
Partnerships.
---------------------------------------------------------------------------

    Regarding Goodman's reference to the jacket loss requirement for 
CWAFs in ASHRAE 90.1-2019, DOE notes that as part of a final rule 
published on May 16, 2012 (``May 2012 final rule'') amending energy 
conservation standards and test procedures for commercial heating, air-
conditioning, and water-heating equipment, DOE addressed the ASHRAE 
90.1 requirement pertaining to jacket loss.\20\ In the May 2012 final 
rule, DOE determined that if ASHRAE adds a prescriptive requirement for 
equipment for which an efficiency level is already specified (e.g., a 
jacket loss requirement in addition to a TE requirement), DOE does not 
have the authority to use a dual descriptor for a single equipment 
type. 77 FR 28928, 28937. Specifically, DOE explained that pursuant to 
42 U.S.C. 6313(a)(6), the Secretary has authority to amend the energy 
conservation standards for specified equipment, but under 42 U.S.C. 
6311(18), the statute's definition of the term ``energy conservation 
standard'' is limited to: (A) A performance standard that prescribes a 
minimum level of energy efficiency or a maximum quantity of energy use 
for a product; or (B) a design requirement for a product. DOE stated 
that the language of EPCA authorizes DOE to establish a performance 
standard or a single design standard. As such, DOE concluded that a 
standard that establishes both a performance standard and a design 
requirement is beyond the scope of DOE's legal authority. Id.\21\ 
Additionally, DOE previously considered including jacket loss in the TE 
calculation in a NOPR published on December 13, 1999. 64 FR 69598, 
69601 (``December 1999 NOPR''). In the December 1999 NOPR, DOE did not 
propose to include jacket loss in the TE calculation, having determined 
that, consistent with adopting industry test standards referenced in 
ASHRAE/IES Standard 90.1-1989, the statute's intent is to assign the 
same meaning to the term ``thermal efficiency'' as its definition in 
the corresponding referenced standards, i.e., 100 percent minus percent 
flue loss. Id. DOE's determination in the December 1999 NOPR was 
informed by a public workshop held on April 14 and 15, 1998, and what 
DOE understood to be

[[Page 10737]]

the consensus of the participants that TE should not include jacket 
loss, because ANSI Z21.47 defined TE without jacket loss. Id. As such, 
DOE acknowledges that the TE as currently determined under ANSI Z21.47 
does not include jacket loss even if it is a requirement of ASHRAE 90.1
---------------------------------------------------------------------------

    \20\ The version of ASHRAE 90.1 that was available at the time 
of the May 2012 final rule (i.e., ASHRAE 90.1-2010) includes the 
same 0.75-percent jacket loss requirement that is in ASHRAE 90.1-
2019.
    \21\ DOE notes that it has adopted dual metrics under 42 U.S.C. 
6313(a)(6)(A), when the American Society of Heating, Refrigerating 
and Air Conditioning Engineers (ASHRAE) has amended ASHRAE Standard 
90.1, Energy Standard for Buildings Except Low-Rise Residential 
Buildings, and set a dual metric and accompanying standard levels. 
See, e.g., 77 FR 28928 (May 16, 2012) (DOE adopted energy 
conservation standards for cooling and heating modes in terms of 
both Energy Efficiency Ratio (EER) and Coefficient of Performance 
(COP) for variable refrigerant flow (VRF) water-source heat pumps 
with cooling capacities at or greater than 135,000 Btu/h and less 
than 760,000 Btu/h (for which DOE did not previously have standards) 
in response to updated standards for such equipment in ASHRAE 
Standard 90.1.) DOE has also adopted a dual metric where a consensus 
agreement has been presented to DOE for adoption as a direct final 
rule (DFR) pursuant to 42 U.S.C. 6295(p)(4). See, e.g., 76 FR 37408 
(June 27, 2011) (For central air conditioners, DOE adopted dual 
metrics (i.e., the Seasonal Energy Efficiency Ratio (SEER) and EER) 
for the hot-dry region as recommended by a consensus agreement 
supported by a variety of interested stakeholders including 
manufacturers and environmental and efficiency advocates.) DOE has 
interpreted these specific statutory provisions as authorizing an 
exception to the general rule previously stated.
---------------------------------------------------------------------------

    As noted, DOE is generally required to adopt a test procedure for 
CWAFs that is consistent with the generally accepted industry testing 
procedures developed or recognized by AHRI or by ASHRAE, as referenced 
in ASHRAE Standard 90.1. (42 U.S.C. 6314(a)(4)(A)) Further, if such 
industry test procedure (i.e., the test procedure referenced in ASHRAE 
Standard 90.1) is updated, DOE must amend its test procedure to be 
consistent with the amended industry test procedure, unless DOE 
determines, by rule published in the Federal Register and supported by 
clear and convincing evidence, that such amended test procedure would 
not meet the requirements in 42 U.S.C. 6314(a)(2) and (3) related to 
representative use and test burden. (42 U.S.C. 6314(a)(4)(B) and (C)) 
Additionally, EPCA also requires that DOE periodically evaluate the 
test procedures for CWAFs to determine whether amended test procedures 
would more accurately or fully comply with the requirements for the 
test procedures to not be unduly burdensome to conduct and be 
reasonably designed to produce test results that reflect energy 
efficiency, energy use, and estimated operating costs during a 
representative average use cycle. (42 U.S.C. 6314(a)(1))
    For the reasons that follow, DOE has tentatively determined that 
incorporating a jacket loss measurement into the test procedure and 
metric for CWAFs would improve the representativeness of the test 
procedure by capturing an attribute of CWAFs other than combustion 
efficiency (i.e., jacket loss) that can have a substantive impact on 
the overall energy use of CWAFs.
    The current TE is essentially a measure of combustion efficiency. 
However, the energy efficiency of the equipment is influenced by 
factors in addition to combustion efficiency (i.e., jacket loss). 
Jacket loss contributes to the overall energy use of a CWAF and is, 
therefore, one of the parameters that determines a CWAF's overall 
efficiency. Heat loss through the cabinet (i.e., jacket loss) is 
proportional to the thickness of the insulation and/or insulative 
material used. DOE tentatively agrees with ASAP that CWAFs with the 
same TE, as determined under the current DOE test procedure, could have 
different performance in the field if one unit has different insulation 
than the other. DOE also notes that the vast majority of CWAFs are 
installed within CUACs located on rooftops, and that these outdoor 
installations will result in greater jacket loss than CWAFs installed 
indoors because of the colder ambient air. As such, DOE tentatively 
agrees with the CA IOUs that performance of a CWAF will vary depending 
on installation location because of different levels of jacket loss. 
Differences in performance based on differences in jacket loss are not 
captured by the current DOE test procedure and metric. Incorporating 
jacket loss into a TE2 metric will therefore account for differences in 
CWAF insulation. Additionally, weighting jacket loss based on 
installation location, which DOE discusses more in the following 
paragraphs, will account for the differences in jacket loss across 
various installation locations.
    DOE is proposing that, for CWAFs that are designed for outdoor 
installation (including but not limited to CWAFs that are weatherized, 
or approved for resistance to wind, rain, or snow) or designed for 
indoor installation in an unheated space (i.e., isolated combustion 
systems),\22\ jacket loss shall be measured in accordance with the 
Section 5.40 of ANSI Z21.47-2021. DOE is proposing to multiply this 
measured jacket loss by jacket loss factors to account for differences 
in installation location. DOE proposes that a jacket loss factor of 1.7 
for CWAFs designed for indoor installation in an unheated space (i.e., 
isolated combustion system), or 3.3 for CWAFs designed for outdoor 
installation (including, but not limited to, CWAFs that are 
weatherized, or approved for resistance to wind, rain, or snow) be 
multiplied by the measured jacket loss before subtracting the product 
from thermal efficiency (i.e., TE2 is calculated as 100 percent minus 
flue and jacket loss, when the jacket loss is the measured jacket loss 
multiplied by the jacket loss factor). DOE is also proposing that the 
jacket loss shall be zero for CWAFs designed for installation indoors 
within a heated space because the heat loss through the CWAF's jacket 
would go directly into the heated space. DOE notes that this approach 
is consistent with the approach taken in appendix N to subpart B of 10 
CFR part 430 for measuring AFUE in residential furnaces, which 
references ASHRAE 103. Therefore, DOE has tentatively determined these 
are the appropriate jacket loss factors to use based on the values 
found in Section 11.2.11 of ASHRAE 103-2017, and is proposing to use 
these factors in newly proposed appendix B.\23\
---------------------------------------------------------------------------

    \22\ This description of a CWAF designed for outdoor 
installation is consistent with a residential weatherized warm air 
furnace specified in 10 CFR 430.2.
    \23\ DOE notes that the jacket loss factor in Section 11.2.11 of 
ASHRAE 103-2017 for equipment intended for indoor installation 
within a heated space is 0.0. As such, jacket loss would be 
calculated as zero. Therefore, as previously mentioned, DOE is 
proposing the jacket loss would be assumed to be zero for CWAFs 
intended for indoor installation within a heated space.
---------------------------------------------------------------------------

    As previously mentioned, DOE references Section 2.39 of ANSI 
Z21.47-2012 (now Section 5.40 in ANSI Z21.47-21), which includes a test 
procedure for determining jacket loss. DOE does not currently reference 
Annex J of ANSI Z21.47-2012, which includes the equation used to 
calculate jacket loss. Annex J also includes Figures J.1 and J.2 which 
are used to determine the coefficient of convection and coefficient of 
radiation for the surface, which are two coefficients used in the 
calculation of jacket loss. DOE is proposing to incorporate by 
reference the jacket loss test procedure specified in Section 5.40 of 
ANSI Z21.47-2021, which includes a reference to Annex J of ANSI Z21.47-
2021, for both gas-fired and oil-fired CWAFs. Specifically, DOE is 
proposing to adopt this test procedure for measuring jacket loss when 
testing to newly proposed appendix B to determine TE2.
    To the extent that manufacturers participate in the industry 
certification program under ASHRAE 90.1, such manufacturers should 
already be measuring jacket loss according to the test procedure 
proposed in this NOPR due to the prescriptive jacket loss requirement 
in ASHRAE 90.1. Based on a review of models on the market, DOE found 
the majority of CWAFs indicate in product literature that they comply 
with the requirements of ASHRAE 90.1, which indicates that many CWAFs 
are already tested for jacket loss.
    DOE is proposing to adopt the industry test standard for 
determining jacket loss that DOE has tentatively determined is 
currently being used by industry, and as such would not be unduly 
burdensome. Additionally, testing according to appendix B would be 
mandatory only at such time as compliance is required with amended 
energy conservation standards based on TE2, should DOE adopt such 
standards. Therefore, DOE proposes to incorporate jacket loss in the 
proposed TE2 metric.
    DOE seeks comment on its proposal to require jacket loss be 
measured when testing CWAFs designed for outdoor

[[Page 10738]]

installation and designed for indoor installation within an unheated 
space when determining TE2 pursuant to newly proposed appendix B, and 
on its proposed method for measuring jacket loss. DOE also seeks 
comment on its proposal that jacket loss for CWAFs intended for indoor 
installation within a heated space would be assumed to be zero, and on 
its proposed jacket loss factors for CWAFs designed for outdoor 
installation and designed for indoor installation within an unheated 
space.
2. Part-Load Performance
    In response to the May 2020 RFI, DOE received comments from NEEA 
and the CA IOUs encouraging DOE to adopt a metric and test procedure 
that account for operation at part load. (NEEA, No. 10 pp. 1-2; CA 
IOUs, No. 8 at p. 1) NEEA and the CA IOUs both asserted that CWAFs 
spend the majority of their time in a low fire mode (i.e., part load) 
and that adopting a metric that includes part load would better 
represent the operation of CWAFs in the field. Id. More specifically, 
NEEA asserted that CWAFs often spend 10 to 20 percent of their time at 
high fire mode (i.e., full load), and that DOE should update its test 
procedure to include reduced firing rates (i.e., part-load) and 
seasonal performance so that the test procedure is more representative 
of an average use cycle.\24\ NEEA recommended a seasonal metric be 
used, asserting that jacket loss, damper leakage, and fan performance 
would be affected by CWAFs installed in colder climates. (NEEA, No. 10 
p.2) NEEA also commented that other DOE test procedures for HVAC 
equipment have been transitioning to measure part-load and seasonal 
performance, and that the CWAF test procedure should likewise be 
updated. (NEEA, No. 10 p. 1) The CA IOUs stated that cyclic losses due 
to cycling of the burners negatively impacts efficiency of a CWAF, and 
that accounting for this would increase the representativeness of the 
test procedure. (CA IOUs, No. 8 at pp. 1-2)
---------------------------------------------------------------------------

    \24\ NEEA referenced the following energy model: Energy Modeling 
of Commercial Gas Rooftop Units in Support of CSA P.8 Standard.
---------------------------------------------------------------------------

    AHRI commented that any additional requirements beyond the current 
test procedure provisions would be a burden to manufacturers, and that 
any changes that affect testing or calculations are likely to be overly 
burdensome compared to any benefits, due to what AHRI characterized as 
the relatively small market for these appliances. (AHRI, No. 7 at p. 
77)
    DOE reviewed the current CWAF market and found that the vast 
majority of CWAFs certified to DOE have two or more stages of heating. 
DOE notes that CWAFs with two or more stages can operate at reduced 
firing rates to meet the building load. Under the current DOE test 
procedure, TE reflects the efficiency of the burner and the efficiency 
of the heat exchanger at full load. When a CWAF burner operates at a 
reduced input rate (i.e., part load), the ratio of heat exchanger 
surface area to burner input rate is increased (in comparison to 
operation at full load), which theoretically should increase the 
efficiency of the CWAF compared to operating at full load, if other 
aspects of operation are consistent. However, depending on the air-fuel 
ratio or other factors impacting combustion efficiency, the combustion 
efficiency could decrease, and therefore, the change in performance, 
including whether efficiency is improved or reduced at part-load, could 
vary from model to model. Therefore, CWAF part-load performance has the 
potential to be substantively different from full-load performance and 
including part-load performance in the measurement of CWAF efficiency 
would allow the efficiency metric to account for this potential 
difference and be more representative. To provide for measured test 
results that are more representative of the average use cycle of CWAFs 
that are two-stage and modulating burner units (i.e., CWAFs that 
operate at less than full load), DOE proposes to include a part-load 
measurement in the test procedure proposed at newly proposed appendix 
B. DOE has tentatively determined that including a part-load test 
procedure within the DOE test procedure would better capture how CWAFs 
operate in the field and would be more representative of the 
performance of CWAFs during an average use cycle, particularly for 
models that have two or more stages of heating. Therefore, DOE is 
proposing to include both part-load and full-load operation tests in 
the newly proposed appendix B.
    Specifically, DOE proposes to require that, for two-stage or 
modulating burner models, the flue loss of the unit under test be 
determined as specified in section 2 of appendix A (formerly 10 CFR 
431.76(c)) at both the maximum and minimum input rates on the nameplate 
of the unit. The jacket loss (as described in section III.C.1 of this 
document) would be determined at the maximum input rate and optionally 
be determined at the minimum input rate. If the jacket loss were 
determined only at the maximum input rate, it would be assigned an 
equivalent value at the minimum input rate. TE2 would then be 
calculated as the average of the efficiencies determined at both the 
maximum and minimum input rates using the flue loss and jacket loss 
determined at each input rate.
    Averaging the performance at the maximum and minimum input rate 
weights both full-load and part-load CWAF operation equally (i.e., 
representing CWAF operation at full load 50 percent of the time and 
part load 50 percent of the time). DOE considered the relationship 
between full-load operation and part-load operation presented in the 
comments from NEEA. However, the 10 to 20 percent estimate of operation 
at full load referenced by NEEA was based on data for climate regions 
represented by Winnipeg, Montreal, and Toronto. DOE has tentatively 
determined that operating conditions represented by these climate zones 
are not representative of the United States, which includes more 
temperate climate zones.
    DOE also considered relying on the part-load and full-load burner 
operating hour calculations for two-stage and modulating furnaces 
specified in Appendix C of ANSI/ASHRAE 103-2017. However, DOE 
tentatively determined that this approach would not be representative 
because the calculations specified in Appendix C of ANSI/ASHRAE 103-
2017 include assumptions that are specific to residential furnaces 
(e.g., national average heating load hours) that may not be 
representative for CWAFs. For example, CWAFs may operate more 
frequently during business hours, whereas a residential furnace may 
operate more frequently during off-business hours when people are more 
likely to be at home.
    DOE tentatively finds that CWAFs spend a substantive amount of time 
in part-load. Absent nationally representative data or information to 
support weighting factors for full-load and part-load performance that 
are more representative of an average use cycle, DOE has tentatively 
determined that weighting both equally is appropriate at this time, 
however DOE seeks comment on this tentative determination.
    DOE seeks comment on its proposal to add a part-load test procedure 
to be incorporated into the newly proposed TE2 metric. DOE also seeks 
comment on its proposal to calculate TE2 by averaging performance at 
the maximum and minimum fire rate and seeks and any related data. DOE 
also requests comment on alternate weighting values, including those 
discussed, that may be more nationally representative of an

[[Page 10739]]

average use, along with any relevant data.

D. Electrical Energy Consumption

    In the May 2020 RFI, DOE noted that the DOE test procedure for 
CWAFs does not include any measurement of electrical consumption in its 
determination of the efficiency of CWAFs, including electrical 
consumption of blowers/fans, controls, or other auxiliary electrical 
consumption. 85 FR 26626, 26632. DOE explained that CWAFs are typically 
part of a single package that also includes air-conditioning equipment, 
and that the test method and metrics for commercial air-conditioning 
and heating equipment (i.e., integrated energy efficiency ratio 
(``IEER'')) accounts for the electrical consumption of the blower; as 
such, the electrical consumption of the blower has not been included in 
the CWAF test method. Id. DOE noted that any auxiliary electrical 
consumption associated only with the furnace operation when heating is 
not accounted for in any metric. Id.
    In the May 2020 RFI, DOE asked for comment on whether it should 
consider including the electrical consumption of CWAFs in the CWAF 
efficiency metric or test procedure, as well as on the merits and 
burdens of such approach. Id. DOE also asked for comment on which 
components' electrical consumption would be appropriate to include, 
noting that the electrical consumption of the CWAF blower is typically 
factored into other commercial equipment efficiency metrics and test 
procedures. Id.
    ASAP, the CA IOUs, and NEEA recommended that DOE account for 
electrical consumption of the CWAF. (CA IOUs, No. 8 at p. 2; ASAP, No. 
5 at p. 1; NEEA, No. 10 at p. 4) More specifically, ASAP urged DOE to 
ensure that all electrical consumption associated with CWAFs (including 
CWAF auxiliary electrical consumption) is captured in either the CWAF 
test procedure or the test procedure for CUACs. Specifically, regarding 
auxiliary electrical consumption, ASAP stated that capturing auxiliary 
electrical consumption would better reflect the efficiency of CWAFs 
during a representative average use cycle, thus providing better 
information to purchasers. (ASAP, No. 5 at p. 2) ASAP also stated that 
the term sheet from the Appliance Standards and Rulemaking Federal 
Advisory Committee (``ASRAC'') working group for CUACs and CWAFs 
contained a recommendation that DOE amend the test procedure for CUACs 
to better capture total fan energy use, including the energy use 
associated with the supply fan operation when the unit is in heating 
mode. (ASAP, No. 5 at p. 1) The CA IOUs also noted that the ASRAC term 
sheet includes a recommendation to update the CUAC test procedure to 
``better represent total fan energy use, including considering (a) 
alternative external static pressures; and (b) operation other than 
mechanical cooling and heating.'' (ASAP, No. 5 at pp. 1-2; CA IOUs, No. 
8 at pp. 2-3) Similarly, NEEA stated that electrical energy should be 
considered in total energy consumption in all operating modes, citing 
that RTUs spend the majority of their time in ventilation mode, and 
that electrical energy consumption of an RTU is 4 to 11 percent of 
total seasonal energy consumption. (NEEA, No. 10 at p. 4) Additionally, 
NEEA stated that the current CWAF test procedure does not capture many 
energy efficient features that are currently available on the market 
and, therefore, does not effectively allow manufacturers to distinguish 
more efficient equipment.\25\ NEEA also encouraged DOE to consider a 
calculation-based test procedure to include other energy using 
components and operating modes. (NEEA, No. 10 at pp. 3-4) DOE also 
received comment from the Joint Advocates in response to the May 2020 
ECS RFI, recommending DOE amend the CWAF test procedure to capture 
auxiliary electrical consumption. (Joint Advocates, EERE-2019-BT-STD-
0042-0023 at p. 3)
---------------------------------------------------------------------------

    \25\ NEEA stated that these efficient components include low 
leak dampers, improved insulation or thermally broken insulation, 
variable speed fans, economizing capability, improved controls, 
demand control ventilation, modulating heat/high turndown furnaces, 
and heat recovery. (NEEA, No. 10 at p. 3)
---------------------------------------------------------------------------

    AHRI, Carrier, and Trane recommended against including the 
electrical consumption of CWAFs in the efficiency metric or test 
procedure. (AHRI, No. 7 at p. 6; Trane, No. 9 at p. 4; Carrier, No. 4 
at p. 3) AHRI stated that the electrical energy consumption of CWAF 
components is minimal compared to the fossil fuel energy used for 
heating. (AHRI, No. 7 at p. 6) Trane explained that combustion fan 
motor wattage is very small as a percentage of these commercial 
furnaces (Trane, No. 9 at p. 4) More specifically, AHRI stated that the 
energy consumption of a combustion fan is a fraction of a percent of 
the total energy consumption. Carrier similarly asserted that the power 
draw of the inducer fan used to create the draft through the furnace is 
minimal compared to the energy of combustion. (Carrier, No. 4 at p. 3) 
AHRI and Trane asserted that the extra burden from retesting and 
certifying to a new metric is not worth adding electrical consumption 
into a new efficiency metric. (AHRI, No. 7 at p. 6; Trane, No. 9 at p. 
4) AHRI and Carrier noted that CWAFs are often sold as part of a 
packaged unit (i.e., within a CUAC), and that the blower and fans are 
included in the performance measurement of the CUAC. (AHRI, No. 7 at p. 
6; Carrier No. 4 at p. 3) AHRI also noted that the total air-
conditioning hours are far greater than the total heating hours. (AHRI, 
No. 7 at p. 6; Carrier, No. 4 at p. 3)
    DOE agrees with stakeholders that CWAFs are typically installed 
within a CUAC, and that the energy consumption of the supply air fan is 
captured in the current CUAC test procedure. DOE notes that the energy 
consumption of the supply air fan during furnace-only operation is not 
captured within the CUAC test procedure; however, DOE has tentatively 
determined that such energy consumption would be better addressed in a 
future amendment to the CUAC test procedure, rather than also 
integrating supply fan consumption into the CWAF test procedure. This 
approach would allow for the supply air fan's energy consumption to be 
captured in a single test procedure. Similarly, DOE notes that many of 
the components that were referenced by NEEA are related to CUAC 
performance. As such, DOE has tentatively determined that these 
components would be better addressed a future CUAC test procedure 
amendment. Therefore, DOE has tentatively determined not to include 
supply fan energy consumption in the CWAF metric.
    DOE also considered whether to include the electrical energy 
consumption of other auxiliary components of CWAFs within the DOE test 
procedure. In a final rule published on May 4, 2016, amending the 
energy conservation standards for CWAFs, DOE analyzed the auxiliary 
energy consumption of CWAFs, finding that on average, auxiliary power 
consumption for the draft inducer was 100 W for gas-fired CWAFs and 220 
W for oil-fired CWAFs. (See section 7B.3 of the Final Rule TSD, EERE-
2013-BT-STD-0021-0050.) DOE also estimated the power consumption of 
other auxiliary components (e.g., 25 W for spark ignition). Id. This 
auxiliary power consumption, as compared to the fossil fuel energy 
input rate, represents a fraction of a percent of the total energy 
consumption of a CWAF. As such, improvements in electrical power 
consumption, if integrated into TE, would have a negligible impact on 
the measured energy efficiency of a CWAF. DOE has tentatively 
determined that incorporating electrical consumption into the 
measurement of CWAF

[[Page 10740]]

efficiency would not substantially improve the representativeness of 
the test procedure and would increase testing burden. DOE also notes 
that including electrical consumption in the determination of CWAF 
efficiency would be a significant deviation from how CWAF efficiency is 
currently measured, for which DOE must demonstrate ``clear and 
convincing evidence'' that such change would more fully comply with the 
requirements of EPCA. Because DOE has tentatively concluded it is 
unlikely that inclusion of electrical energy in the TE metric would 
impact the thermal efficiency rating, DOE tentatively concludes that 
such a change would not meet the clear and convincing threshold 
established by DOE. Therefore, DOE is not proposing to update the CWAF 
test procedure to include electrical consumption.

E. Other Test Procedure Updates and Clarifications

1. Flue Temperature Measurement in Models With Multiple Vent Hoods
    In the May 2020 RFI, DOE noted that neither the DOE test procedure 
nor the ANSI Z21.47 test procedure specifies how to perform the flue 
temperature measurement if a unit has multiple vent hoods, and that 
models are currently available on the market with multiple vent hoods. 
85 FR 26626, 26631. DOE notes that in this NOPR, as in the May 2020 
RFI, DOE's references to a ``vent hood'' are synonymous with a ``vent 
pipe.''
    In the May 2020 RFI, DOE requested comment on how CWAFs with more 
than one vent hood are currently tested and whether it should consider 
adding provisions in the DOE test procedures to address measuring the 
flue gas temperature of a unit with multiple vent hoods. DOE also asked 
how best to measure flue gas temperature in such units. Id.
    AHRI stated that the manufacturers' installation instructions 
should include information regarding the use of multiple vents and each 
vent's functionality. AHRI stated that if the vent hood modules are the 
same size, the results are averaged; however, if they are different 
sizes, the test results for each vent hood should be adjusted 
accordingly before averaging the results. AHRI stated that, for 
example, if one vent is intended to exhaust two-thirds of the flue 
product and the second is intended to exhaust the remaining one-third, 
then this should be specified in the installation instructions, and a 
weighted average used to determine the flue gas temperature. (AHRI, No. 
7 at p. 5)
    Trane stated that DOE should use the instructions in both the 
installation operation manuals as well as the supplemental testing 
instruction (``STI'') supplied when a model is certified to DOE for 
determining how to measure flue gas for models with multiple vent 
hoods. (Trane, No. 9 at p. 3)
    Carrier stated that the procedure it uses for models with multiple 
vent hoods is to analyze combustion products and measure flue 
temperature separately in each vent hood, and then use the averaged 
data of all vents to calculate TE. (Carrier, No. 4 at p. 2)
    DOE tentatively agrees that results should be measured in each vent 
hood and weighted proportionally to the size of each vent hood when 
calculating TE. For units with multiple vent hoods of the same size, 
this approach would result in the measurements being averaged. 
Therefore, in order to ensure consistency between tests, DOE is 
proposing to add instructions to clarify the test method for models 
with multiple vent hoods. DOE proposes that measurements used to 
calculate TE (e.g., flue gas temperature, CO<INF>2</INF> in flue 
gasses), be made separately for each vent hood, and that they are 
weighted proportionally to the size of each vent hood when calculating 
flue loss. Further, DOE proposes that test requirements, such as 
determining when equilibrium conditions occur based on the flue gas 
temperature, are determined based these weighted measurements. This 
proposal is predicated on the assumption that the amount (i.e., mass 
flow) of flue exhaust exiting each vent hood is proportional to the 
hood size. DOE recognizes that vent hood ``size'' may be measured in 
various ways, and therefore is proposing to specify that vent hoods 
size would be determined by calculating the outlet face area of the 
vent hood. As noted, DOE is proposing this additional procedure for 
clarification and to improve test repeatability, as ANSI Z21.47-2021 
does not address flue temperature measurements in CWAFs with multiple 
vent hoods.
    DOE seeks comment on its proposal to provide instructions in the 
DOE test procedure for testing units with multiple vent hoods.
    DOE seeks comment on its assumption that the amount (i.e., mass 
flow) of flue exhaust exiting each vent hood is proportional to the 
size of the vent hood. Furthermore, DOE seeks comment on its proposal 
to compare vent hood outlet face areas to determine vent hood size.
2. Flue Temperature Measurement in Models With Vent Space Limitations
    In the May 2020 RFI, DOE noted that Section 2.16 of ANSI Z21.47-
2012 and Section 5.16 of ANSI Z21.47-2016 both specify measuring the 
flue gas temperature in the vent pipe using nine individual 
thermocouples placed in specific locations; however, these sections do 
not provide guidance on how to measure the flue gas temperature if the 
vent size constrains the space where the thermocouples are to be placed 
to the point that normal operation of the unit is inhibited when nine 
thermocouples are installed. 85 FR 26626, 26631-26632. DOE notes this 
is also true of Section 5.16 in ANSI Z21.47-2021. In the May 2020 RFI, 
DOE noted that a vent may be so small (if, for example, a unit has 
multiple vents) that it is not practical to measure the flue gas 
temperature using nine thermocouples. DOE also explained that during 
testing of one unit with a particularly small vent hood, DOE found that 
placing nine \26\ thermocouples was not practical due to space 
limitations. 81 FR 26626, 26631-26632.
---------------------------------------------------------------------------

    \26\ In the May 2020 RFI, DOE stated that DOE found that placing 
more than four thermocouples for that particular test unit was not 
practical due to space limitations. 85 FR 26626, 26632. However, 
this was a typographical error; DOE intended to state that placing 
nine thermocouples (not more than four) was not practical in this 
instance due to space limitations.
---------------------------------------------------------------------------

    In the May 2020 RFI, DOE asked for comment on how CWAFs with vent 
size constraints are currently tested and whether DOE should consider 
adding provisions in the DOE test procedure to address measuring the 
flue gas temperature when space limitations preclude the use of nine 
thermocouples. DOE also asked how best to measure flue gas temperature 
in such units. 81 FR 26626, 26632.
    AHRI stated that the manufacturer's test instructions may specify 
that the number of thermocouples be limited due to space constraints 
within the draft hood. In such instances, the testing laboratory will 
follow the manufacturer's test instructions for set-up. (AHRI, No. 7 at 
p. 6) Trane stated that it believes the manufacturer will communicate 
how measurements were performed either in the STI or installation 
manual to achieve the performance metric rating that is certified, and 
that DOE should follow those instructions. (Trane, No. 9 at p. 3) 
Carrier acknowledged that, at times, it is impossible to fit nine 
thermocouples adequately in a smaller vent and stated that it uses the 
procedure from ANSI/ASHRAE 103, which specifies the number of 
thermocouples depending on

[[Page 10741]]

the diameter of the vent. Carrier further stated that ANSI/ASHRAE 103 
requires five thermocouples for vents 2 inches in diameter and smaller, 
nine thermocouples for vents greater than 2 inches in diameter, and 17 
thermocouples for a stack measurement. (Carrier, No. 4 at p. 2)
    In order to ensure consistency and repeatability in the application 
of the test method for models with small vent hoods, DOE recognizes the 
need to specify how to perform the DOE test procedure when nine 
thermocouples do not fit inside the vent hood. Although AHRI and Trane 
suggest allowing the manufacturer to specify how the thermocouples 
should be installed, this could lead to inconsistent test set-up and 
results for models with small vents if manufacturers choose different 
approaches for testing. Therefore, DOE is proposing to align its test 
procedure with ASHRAE 103-2017. More specifically, DOE is proposing to 
specify in the DOE test procedure that when testing gas- and oil-fired 
CWAFs, the flue gas temperatures shall be measured in the vent hood 
using nine individual thermocouples when the vent hood is larger than 2 
inches in diameter and may optionally be measured using five individual 
thermocouples when the vent hood is 2 inches or smaller in diameter.
    DOE seeks comment on the proposal to specify in the DOE test 
procedure that when testing gas- and oil-fired CWAFs, the flue gas 
temperatures shall be measured in the vent hood using nine individual 
thermocouples, or if the vent hood is 2 inches or smaller in diameter, 
five thermocouples may optionally be used.
3. Input Rate Tolerance
    In the May 2020 RFI, DOE noted that its test procedure for gas-
fired CWAFs references the test method in ANSI Z21.47, and that the 
thermal efficiency test in Section 2.39 of ANSI Z21.47 requires that 
the test be conducted at normal inlet pressure and at 100 percent of 
normal input rate (i.e., the maximum hourly Btu input rating specified 
by the manufacturer). 10 CFR 431.76(c)(1). DOE noted that no tolerance 
is provided on the input rate in section 2.39, so when taken literally, 
this provision could be interpreted to require that the firing rate be 
exactly 100 percent of the nominal input rate. DOE further noted that 
other types of fossil-fuel-fired equipment such as commercial packaged 
boilers, commercial water heaters, residential water heaters, 
residential furnaces, and residential boilers require the input rate 
during testing to be within <plus-minus>2 percent of the nameplate 
input rate. 85 FR 26626, 26631.
    In the May 2020 RFI, DOE asked for comment on whether industry uses 
a tolerance when testing to ANSI Z21.47, and if so, what tolerance is 
used. DOE also asked whether a tolerance should be specified for the 
input rate during testing of gas-fired CWAFs, and if so, what tolerance 
would be appropriate. Id.
    Carrier stated that it uses a minor plus-and-minus tolerance on 
input rate and that it understands that this approach is not included 
in ANSI Z21.47, but it has been used on furnace testing at Carrier for 
many years.\27\ (No. 4 at p. 2) Trane and AHRI both commented that 
section 5.4.4 \28\ of ANSI Z21.47-2016 includes a <plus-minus>2 percent 
tolerance on input rate. (AHRI, No. 7 at p. 5; Trane, No. 9 at p. 3) 
The CA IOUs recommend including a tolerance of <plus-minus>2 percent of 
rated input for gas-fired CWAFs, consistent with the commercial boiler 
test methods described in AHRI 1500-2015. (CA IOUs, No. 8 at p. 4.)
---------------------------------------------------------------------------

    \27\ Carrier did not provide a specific value for the tolerance 
it uses for CWAF testing.
    \28\ DOE understands commenters to have intended to reference 
section 5.5.4 as there is no section 5.4.4 in ANSI Z21.47-2016.
---------------------------------------------------------------------------

    DOE notes that Sections 5.5.4 of ANSI Z21.47-2016 and 5.5.4 of ANSI 
Z21.47-2021 both specify a <plus-minus>2 percent tolerance on the 
manufacturer's specified hourly Btu input rating, and that the same 
<plus-minus>2 percent input rate tolerance is also specified in Section 
2.5.4 of ANSI Z21.47-2012, which is currently incorporated by reference 
in the current DOE test procedure. As discussed in section III.B.3 of 
this document, DOE is proposing to reference the Sections of ANSI 
Z21.47-2021 that correspond to the sections in ANSI Z21.47-2012 that 
are currently referenced, including Section 5.5 of ANSI Z21.47-2021. 
This proposal, therefore, incorporates Section 5.5.4 of ANSI Z21.47-
2021, which includes the <plus-minus>2 percent tolerance on the 
manufacturer's specified hourly Btu input rating.
4. Flue Loss Determination
    Section 2.39 of ANSI Z21.47-2012 and Section 5.40 ANSI Z21.47-2021 
reference Annex I for the determination of flue loss that is used in 
the TE calculation. Annex I includes two methods for determining flue 
loss--one method that uses a calculation, and one method that uses 
nomographs shown in Figures I.1 and I.2 of ANSI Z21.47-2021. The 
nomograph method may only be used when the heating value, specific 
gravity, and flue gas CO<INF>2</INF> of a CWAF fall within a specified 
range.\29\ If these conditions are met, either calculation method may 
be used. DOE notes that the option to use either method may result in 
issues with repeatability if the determination of flue loss varies when 
using each method. Therefore, DOE is proposing in section 4 of appendix 
A (formerly 10 CFR 431.76(e)) that the calculation method must be used 
when determining flue loss. DOE is proposing use of the calculation 
method rather than the nomograph method because the nomograph method is 
not applicable for all tests, and the calculation method is likely to 
provide better repeatability by eliminating subjective differences in 
interpreting the nomograph.
---------------------------------------------------------------------------

    \29\ Heating value for natural gas or propane must be 970-1100 
Btu/ft\3\ or 2466-2542 Btu/ft\3\, respectively. Specific gravity for 
natural gas or propane must be 0.57-0.70 or 1.522-15.74, 
respectively. Ultimate carbon dioxide for natural gas or propane 
must be 11.7-12.2% or 13.73-13.82%, respectively.
---------------------------------------------------------------------------

    DOE seeks comment on its proposal to require the calculation method 
specified in Annex I of ANSI Z21.47-2021 be used when determining flue 
loss, and not the nomograph method.

F. Test Procedure Costs, Harmonization, and Other Topics

1. Test Procedure Costs and Impact
    In this NOPR, DOE proposes to amend the existing test procedure for 
CWAF for determining TE by incorporating by reference the most up-to-
date versions of the industry standards currently referenced in the DOE 
test procedure, and by providing additional detail for the test setup 
for models with multiple vent hoods and models with vent hoods having 
space limitations. DOE has tentatively determined that these proposed 
amendments for determining TE would not be unduly burdensome for 
manufacturers to conduct, and that the proposed test procedures for 
this equipment are consistent with the industry test procedure updates. 
DOE has tentatively determined that the proposed amendments to the test 
procedure for determining TE would improve the representativeness, 
accuracy, and reproducibility of the test results and would not be 
unduly burdensome for manufacturers to conduct. DOE expects that the 
proposed test procedure in appendix A for measuring and TE would not 
increase testing costs.
    DOE also is proposing to establish a new TE2 metric and establish a 
new appendix B, which would include the test procedure for determining 
TE2. DOE estimates that the additional test cost due to the additional 
part-load test and jacket loss test required for the TE2

[[Page 10742]]

metric would be $2,200, compared to the current DOE test procedure, 
which DOE estimates to be $4,200 at a third-party laboratory (i.e., a 
total estimated cost of $6,400 per tested unit for the amended TE2 test 
procedure). Therefore, assuming two units are tested per basic 
model,\30\ DOE estimates the testing cost associated with the newly 
proposed appendix B test procedure to be $12,800 per basic model.
---------------------------------------------------------------------------

    \30\ Per the sampling requirements specified at 10 CFR 
429.11(b), manufacturers are required to test at least two units to 
determine the rating for a basic model, except if only one unit of 
the basic model is produced.
---------------------------------------------------------------------------

    In accordance with 10 CFR 429.41, CWAF manufacturers may elect to 
use an alternative efficiency determination method (``AEDM'') to rate 
models for the TE2 metric, which significantly reduces testing costs to 
industry. DOE estimates the per-manufacturer cost to develop and 
validate an AEDM to determine TE2 for CWAF equipment to be $17,300. DOE 
estimates a cost of $46 per basic model for determining energy 
efficiency using a validated AEDM.\31\
---------------------------------------------------------------------------

    \31\ DOE's estimated initial cost to develop and validate an 
AEDM includes (1) 80 hours to develop the AEDM based on existing 
simulation tools; (2) an additional 16 hours to validate the AEDM 
for two basic models at the cost of an engineering calibration 
technician wage of $46 per hour; and (3) the cost of third-party 
testing of two units per validation class (as required in 10 CFR 
429.70(c)(2)(iv)). DOE estimated the additional per basic model cost 
to determine efficiency using an AEDM assuming 1 hour per basic 
model at the cost of an engineering calibration technician wage of 
$46 per hour.
---------------------------------------------------------------------------

    Additionally, DOE has tentatively determined that the proposed 
appendix B test procedure and TE2 calculation would alter the measured 
energy efficiency of a CWAF.
    As previously discussed, the proposed test procedure provisions 
regarding TE2 would not be mandatory unless and until compliance is 
required with amended energy conservation standards that rely on TE2. 
Because DOE is not referencing a prevailing industry test procedure for 
determination of TE2, DOE expects that the updated DOE test procedure 
in appendix B would increase the testing burden on CWAF manufacturers 
if use of appendix B were required in the future. However, DOE has 
tentatively determined that the test procedure amendments, if 
finalized, would not require manufacturers to redesign any of the 
covered equipment, would not require changes to how the equipment is 
manufactured, and would not impact the utility of the equipment.
    DOE seeks comment on its understanding of the impact of the test 
procedure proposals in this NOPR, specifically with respect to DOE's 
estimated test costs, and DOE's initial conclusion regarding the 
testing costs associated with the proposed test procedure for TE2 as 
compared to the current test procedure.
2. Harmonization With Industry Standards
    DOE's established practice is to adopt relevant industry standards 
as DOE test procedures unless such methodology would be unduly 
burdensome to conduct or would not produce test results that reflect 
the energy efficiency, energy use, water use (as specified in EPCA) or 
estimated operating costs of that product during a representative 
average use cycle. 10 CFR 431.4; section 8(c) of appendix A 10 CFR part 
430 subpart C. In cases where the industry standard does not meet EPCA 
statutory criteria for test procedures, DOE will make appropriate 
modifications to the DOE test procedure through the rulemaking process.
    The current test procedures for CWAF at 10 CFR 431.76 incorporates 
by reference UL 727-2006 for testing oil-fired CWAFs, HI BTS-2000 for 
performing fuel oil analysis and for calculating flue loss of oil-fired 
CWAFs, ANSI Z21.47-2012 for testing gas-fired CWAFs, and ANSI/ASHRAE 
103-2007 for testing condensing gas-fired CWAFs. As discussed, the 
proposed amendments to the DOE test procedure for determining TE would 
update the references to the incorporated industry testing standards. 
Also as discussed, DOE is proposing to adopt a new metric, TE2, for 
CWAFs. There is no industry testing standard that provides for 
determining TE2. However, the test procedure provisions that provide 
the measured inputs for determining TE2 rely on the same industry 
testing standards DOE is proposing to reference for determining TE.
    DOE requests comments on the benefits and burdens of the proposed 
updates and additions to industry standards referenced in the test 
procedure for CWAFs.
    DOE recognizes that adopting industry standards with modifications 
imposes a burden on industry (i.e., manufacturers face increased costs 
if the DOE modifications require different testing equipment or 
facilities). DOE seeks comment on the degree to which the DOE test 
procedure should consider and be harmonized further with the most 
recent relevant industry standards for CWAFs, and whether there are any 
changes to the Federal test method that would provide additional 
benefits to the public. DOE also requests comment on the benefits and 
burdens of, or any other comments regarding adopting of, any industry/
voluntary consensus-based or other appropriate test procedure, without 
modification.

G. Compliance Date

    EPCA prescribes that if DOE amends a test procedure, all 
representations of energy efficiency and energy use, including those 
made on marketing materials and product labels, must be made in 
accordance with an amended test procedure, beginning 360 days after 
publication of such a test procedure final rule in the Federal 
Register. (42 U.S.C. 6314(d)(1))
    To the extent the modified test procedure proposed in this document 
is required only for the evaluation and issuance of updated efficiency 
standards, use of the modified test procedure, if finalized, would not 
be required until the compliance date of updated standards.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Order 12866

    The Office of Management and Budget (``OMB'') has determined that 
this test procedure rulemaking does not constitute a significant 
regulatory action under section 3(f) of Executive Order (``E.O.'') 
12866, Regulatory Planning and Review, 58 FR 51735 (Oct. 4, 1993). 
Accordingly, this action was not subject to review under the Executive 
order by the Office of Information and Regulatory Affairs (``OIRA'') in 
OMB.

B. 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 (Aug. 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 DOE rulemaking process. 68 FR 7990. DOE has made 
its procedures and policies available on the Office of the General 
Counsel's website: www.energy.gov/gc/office-general-counsel.
    The following sections detail DOE's IRFA for this test procedure 
rulemaking.

[[Page 10743]]

1. Description of Why Action Is Being Considered
    DOE is proposing to amend the existing DOE test procedures for 
CWAFs in satisfaction of the 7-year review requirement specified in 
EPCA. (42 U.S.C. 6314(a)(1)(A)(ii)).
2. Objective of, and Legal Basis for, Rule
    EPCA authorizes DOE to regulate the energy efficiency of a number 
of consumer products and certain industrial equipment. (42 U.S.C. 6291-
6317) Title III, Part C \32\ of EPCA, added by Public Law 95-619, Title 
IV, section 441(a), established the Energy Conservation Program for 
Certain Industrial Equipment, which sets forth a variety of provisions 
designed to improve energy efficiency. (42 U.S.C. 6311-6317) This 
equipment includes CWAFs, the subject of this document. (42 U.S.C. 
6311(1)(J))
---------------------------------------------------------------------------

    \32\ For editorial reasons, upon codification in the U.S. Code, 
Part C was redesignated Part A-1.
---------------------------------------------------------------------------

    Further, if such an industry test procedure is amended, DOE must 
amend its test procedure to be consistent with the amended industry 
test procedure, unless DOE determines, by rule published in the Federal 
Register and supported by clear and convincing evidence, that such 
amended test procedure would not meet the requirements in 42 U.S.C. 
6314(a)(2) and (3) related to representative use and test burden. (42 
U.S.C. 6314(a)(4)(B))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including CWAFs, to 
determine whether amended test procedures would more accurately or 
fully comply with the requirements for the test procedures to not be 
unduly burdensome to conduct and be reasonably designed to produce test 
results that reflect energy efficiency, energy use, and estimated 
operating costs during a representative average use cycle. (42 U.S.C. 
63146314(a)(1)(A))
3. Description and Estimate of Small Entities Regulated
    For manufacturers of CWAFs, the Small Business Administration 
(``SBA'') has set a size threshold, which defines those entities 
classified as ``small businesses'' for the purposes of the statute. DOE 
used the SBA's small business size standards to determine whether any 
small entities would be subject to the requirements of the rule. See 13 
CFR part 121. The equipment covered by this rule are classified under 
North American Industry Classification System (``NAICS'') code 
333415,\33\ ``Air-Conditioning and Warm Air Heating Equipment and 
Commercial and Industrial Refrigeration Equipment Manufacturing.'' In 
13 CFR 121.201, the SBA sets a threshold of 1,250 employees or fewer 
for an entity to be considered as a small business for this category.
---------------------------------------------------------------------------

    \33\ The size standards are listed by NAICS code and industry 
description and are available at: www.sba.gov/document/support--
table-size-standards (Last accessed July 16, 2021).
---------------------------------------------------------------------------

    DOE reviewed the test procedures proposed in this NOPR under the 
provisions of the Regulatory Flexibility Act and the procedures and 
policies published on February 19, 2003. DOE's analysis relied on 
publicly available databases to identify potential small businesses 
that manufacture equipment covered in this rulemaking. DOE utilized the 
California Energy Commission's Modernized Appliance Efficiency Database 
System (``MAEDbS''),\34\ EPA's ENERGY STAR Database,\35\ and the DOE's 
Certification Compliance Database (``CCD'') \36\ to identify to 
manufacturers. DOE identified eight original equipment manufacturers 
(``OEMs'') of CWAFs affected by this rulemaking. DOE screened out 
companies that do not meet the definition of a ``small business'' or 
are foreign-owned and operated. Of these eight OEMs, DOE identified one 
small, domestic OEM for consideration. DOE used subscription-based 
business information tools to determine headcount and revenue of the 
small business.
---------------------------------------------------------------------------

    \34\ MAEDbS can be accessed at 
www.cacertappliances.energy.ca.gov/Pages/Search/AdvancedSearch.aspx 
(Last accessed July 15, 2021).
    \35\ ENERGY STAR-certified products can be found in the ENERGY 
STAR database accessed at www.energystar.gov/productfinder/product/certified-commercial-water-heaters/results (Last accessed July 15, 
2021).
    \36\ Certified equipment in the CCD are listed by product class 
and can be accessed at www.regulations.doe.gov/certification-data/#q=Product_Group_s%3A* (Last accessed July 15, 2021).
---------------------------------------------------------------------------

4. Description and Estimate of Compliance Requirements
    In this NOPR, DOE proposes to amend the existing test procedure for 
CWAFs when determining TE by incorporating by reference the most up-to-
date versions of the industry standards currently referenced in the DOE 
test procedure, and to provide additional detail for the test setup for 
models with multiple vent hoods and models with vent hoods having space 
limitations. DOE proposes to update appendix A (formerly 10 CFR 
431.76), ``Uniform test method for the measurement of energy efficiency 
of commercial warm air furnaces'' as follows:
    (1) Incorporate by reference UL 727-2018 (previously UL 727-2006) 
for testing oil-fired CWAFs;
    (2) Incorporate by reference AHRI 1500-2015 (previously HI BTS-
2000) for performing fuel oil analysis and for calculating flue loss of 
oil-fired CWAFs;
    (3) Incorporate by reference ANSI Z21.47-2021 (previously ANSI 
Z21.47-2012) for testing gas-fired CWAFs;
    (4) Incorporate by reference ANSI/ASHRAE 103-2017 (previously ANSI/
ASHRAE 103-2007) for testing condensing gas-fired CWAFs;
    (5) Incorporate by reference the standards referenced in UL 727-
2018 (i.e., NFPA 97-2003), AHRI 1500-2015 (i.e., ASTM D396-14a, ASTM 
D240-09, ASTM D4809-09a, and ASTM D5291-10), and ANSI Z21.47-2021 
(i.e., ANSI/ASME PTC 19.3-1974 (R2004)) that are necessary in 
performing the DOE test procedure;
    (6) Clarify how to test units with multiple vent hoods, and units 
with vent hoods that are 2 inches in diameter or smaller; and
    DOE also proposes to establish a new test procedure and metric for 
``TE2'' in a new appendix B to 10 CFR 431.72, which manufacturers could 
use to make voluntary representations, and which would be mandatory 
only at such time as compliance is required with amended energy 
conservation standards based on TE2, should DOE adopt such standards. 
The proposed new TE2 metric accounts for flue losses in a manner 
identical to the existing TE metric, and accounts for jacket losses and 
part-load operation.
    Items (1) through (5) incorporate by reference the most up-to-date 
versions of the industry standards currently referenced in the DOE test 
procedure. Item (6) includes clarifications intended to improve 
consistency and reproducibility of test procedure results. The industry 
test procedure ANSI Z21.47 does not specify how to test units with 
multiple vent hoods or units with vent hoods that are too small to fit 
the required number of thermocouples. DOE is proposing to add 
clarifications and guidance to address these scenarios. DOE has 
tentatively determined that these proposed amendments in this NOPR 
would improve the representativeness, accuracy, and reproducibility of 
the test results and would not increase third-party laboratory testing 
costs.
    In item (7), DOE proposes to adopt appendix B, which includes the 
relevant test procedure requirements for measuring TE2, an efficiency 
metric proposed by DOE which incorporates jacket loss and CWAF 
performance at reduced firing rates. The proposed NOPR amendments would 
not require

[[Page 10744]]

manufacturers to re-rate models, as DOE energy conservation standards 
do not currently require TE2 ratings. As such, the test procedure 
amendments do not result in industry costs.
    Should DOE adopt energy conservation standards based on the TE2 
metric in proposed appendix B in the future, DOE anticipates 
manufacturers would incur costs to re-rate models as result of the 
standards. DOE expects the proposed test procedure in appendix B for 
measuring TE2 would increase testing costs compared to the current DOE 
test procedure. The current DOE test procedure costs approximately 
$4,200 per unit for third-party laboratory testing. DOE estimates the 
cost for third-party laboratory testing according to the proposed 
appendix B to be $6,400 per unit.
    If CWAF manufacturers conduct testing to certify a basic model, two 
units are required to be tested per basic model. The test cost, 
according to the proposed amendments, would be $12,800 per basic 
model.\37\ However, manufacturers are not required to perform 
laboratory testing on all basic models, as CWAF manufacturers may elect 
to use AEDMs.\38\ An AEDM is a computer modeling or mathematical tool 
that predicts the performance of non-tested basic models. These 
computer modeling and mathematical tools, when properly developed, can 
provide a means to predict the energy usage or efficiency 
characteristics of a basic model of a given covered product or 
equipment and reduce the burden and cost associated with testing. DOE 
estimates the cost to develop and validate an AEDM for CWAFs to be 
$17,300, which includes testing of two models per validation class. 
Additionally, DOE estimates a cost of approximately $46 per basic model 
for determining energy efficiency using the validated AEDM.
---------------------------------------------------------------------------

    \37\ The cost to test one unit is $6,400. The cost to test two 
units is $12,800.
    \38\ In accordance with 10 CFR 429.70.
---------------------------------------------------------------------------

    DOE estimates the range of potential costs for the one domestic, 
small OEM. When developing cost estimates for the small OEM, DOE 
considers the cost to develop the AEDM simulation tool, the costs to 
validate the AEDM through testing, and the cost to rate basic models 
using the AEDM.
    DOE research indicates that the one small manufacturer has average 
annual revenues of $3.3 million. DOE understands this OEM to 
manufacture four basic models. Therefore, DOE estimates that the 
associated re-rating costs for this manufacturer to be approximately 
$17,400 when making use of AEDMs. The cost for this small manufacturer 
to re-rate all basic models is estimated to be less than 1 percent of 
annual revenue.
    DOE requests comment on the number of small OEMs DOE identified. 
DOE also seeks comment on the potential costs this small manufacturer 
may incur.
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 proposes to reduce burden on manufacturers, including small 
businesses, by allowing AEDMs in lieu of physically testing all basic 
models. The use of an AEDM is less costly than physical testing of CWAF 
models. Without AEDMs, DOE estimates the cost to physically test all 
CWAF basic models for the identified small manufacturer to be 
approximately $51,200.
    Additional compliance flexibilities may be available through other 
means. EPCA provides that a manufacturer whose annual gross revenue 
from all of its operations does not exceed $8 million may apply for an 
exemption from all or part of an energy conservation standard for a 
period not longer than 24 months after the effective date of a final 
rule establishing the standard. (42 U.S.C. 6295(t)) Additionally, 
manufacturers subject to DOE's energy efficiency standards may apply to 
DOE's Office of Hearings and Appeals for exception relief under certain 
circumstances. Manufacturers should refer to 10 CFR part 430, subpart 
E, and 10 CFR part 1003 for additional details.

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of CWAFs must certify to DOE that their products 
comply with any applicable energy conservation standards. To certify 
compliance, manufacturers must first obtain test data for their 
products according to the DOE test procedures, including any amendments 
adopted for those test procedures. DOE has established regulations for 
the certification and recordkeeping requirements for all covered 
consumer products and commercial equipment, including CWAFs. (See 
generally 10 CFR part 429.) The collection-of-information requirement 
for the certification and recordkeeping is subject to review and 
approval by OMB under the Paperwork Reduction Act (``PRA''). This 
requirement has been approved by OMB under OMB control number 1910-
1400. Public reporting burden for the certification is estimated to 
average 35 hours per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

D. Review Under the National Environmental Policy Act of 1969

    In this NOPR, DOE proposes test procedure amendments that it 
expects will be used to develop and implement future energy 
conservation standards for CWAFs. DOE has 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 DOE's implementing regulations at 10 CFR part 1021. 
Specifically, DOE has determined that adopting test procedures for 
measuring energy efficiency of consumer products and industrial 
equipment is consistent with activities identified in 10 CFR part 1021, 
appendix A to subpart D, A5 and A6. Accordingly, neither an 
environmental assessment nor an environmental impact statement is 
required.

E. Review Under Executive Order 13132

    Executive Order 13132, ``Federalism,'' 64 FR 43255 (Aug. 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 to 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 this proposed

[[Page 10745]]

rule and has determined that it would 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 this proposed 
rule. States can petition DOE for exemption from such preemption to the 
extent, and based on criteria, set forth in EPCA. (42 U.S.C. 4316(b); 
42 U.S.C. 6297(d)) No further action is required by Executive Order 
13132.

F. Review Under Executive Order 12988

    Regarding the review of existing regulations and the promulgation 
of new regulations, section 3(a) of Executive Order 12988, ``Civil 
Justice Reform,'' 61 FR 4729 (Feb. 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, (3) provide a clear legal standard for affected 
conduct rather than a general standard, and (4) 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 
sections 3(a) and 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, 
the proposed rule meets the relevant standards of Executive Order 
12988.

G. Review Under the Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (``UMRA'') 
requires each Federal agency to assess the effects of Federal 
regulatory actions on State, local, and Tribal governments and the 
private sector. Public Law 104-4, sec. 201 (codified at 2 U.S.C. 1531). 
For a proposed regulatory action likely to result in a rule that may 
cause the expenditure by State, local, and Tribal governments, in the 
aggregate, or by the private sector of $100 million or more in any one 
year (adjusted annually for inflation), section 202 of UMRA requires a 
Federal agency to publish a written statement that estimates the 
resulting costs, benefits, and other effects on the national economy. 
(2 U.S.C. 1532(a), (b)) The 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 FR 12820; also available 
at https://energy.gov/gc/office-general-counsel. DOE examined this 
proposed rule according to UMRA and its statement of policy and 
determined that the rule contains neither an intergovernmental mandate, 
nor a mandate that may result in the expenditure of $100 million or 
more in any year, so these requirements do not apply.

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

    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.

I. Review Under Executive Order 12630

    DOE has determined, under Executive Order 12630, ``Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights'' 53 FR 8859 (March 18, 1988), that this proposed regulation 
would not result in any takings that might require compensation under 
the Fifth Amendment to the U.S. Constitution.

J. Review Under Treasury and General Government Appropriations Act, 
2001

    Section 515 of 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 (Feb. 22, 2002), and 
DOE's guidelines were published at 67 FR 62446 (Oct. 7, 2002). Pursuant 
to OMB Memorandum M-19-15, Improving Implementation of the Information 
Quality Act (April 24, 2019), DOE published updated guidelines which 
are available at www.energy.gov/sites/prod/files/2019/12/f70/DOE%20Final%20Updated%20IQA%20Guidelines%20Dec%202019.pdf. DOE has 
reviewed this proposed rule under the OMB and DOE guidelines and has 
concluded that it is consistent with applicable policies in those 
guidelines.

K. 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 OMB, 
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.
    The proposed regulatory action to amend the test procedure for 
measuring the energy efficiency of CWAFs 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, nor has it been designated as a significant energy action by 
the Administrator of OIRA. Therefore, it is not a significant energy 
action, and, accordingly, DOE has not prepared a Statement of Energy 
Effects.

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

    Under section 301 of the Department of Energy Organization Act 
(Pub. L. 95-

[[Page 10746]]

91; 42 U.S.C. 7101), 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; ``FEAA'') 
Section 32 essentially provides in relevant part that, where a proposed 
rule authorizes or requires use of commercial standards, the notice of 
proposed rulemaking must inform the public of the use and background of 
such standards. In addition, section 32(c) requires DOE to consult with 
the Attorney General and the Chairman of the Federal Trade Commission 
(``FTC'') concerning the impact of the commercial or industry standards 
on competition.
    The proposed modifications to the test procedure for CWAF would 
incorporate testing methods contained in certain sections of the 
following commercial standards: UL 727-2018, AHRI 1500-2015 ANSI 
Z21.47-2021, and ANSI/ASHRAE 103-2017. DOE has evaluated these 
standards and is unable to conclude whether they fully comply with the 
requirements of section 32(b) of the FEAA (i.e., whether it was 
developed in a manner that fully provides for public participation, 
comment, and review). DOE will consult with both the Attorney General 
and the Chairman of the FTC concerning the impact of these test 
procedures on competition, prior to prescribing a final rule.

M. Description of Materials Incorporated by Reference

    In this NOPR, DOE proposes to incorporate by reference the 
following standards:
    (1) UL 727-2018. This test standard provides instruction for how to 
test oil-fired CWAFs.
    Copies of UL 727-2018 can be obtained from Underwriters 
Laboratories, Inc., 2600 NW. Lake Rd., Camas, WA 98607-8542, (360) 817-
5500 or online at: standardscatalog.ul.com.
    (2) ANSI Z21.47-2021. This test standard provides instruction for 
how to test gas-fired CWAFs.
    (3) ASHRAE 103-2017. This test standard provides instruction for 
how to test residential furnaces and boilers, which DOE is referencing 
for the purpose of providing instruction for testing condensing gas-
fired CWAFs.
    (4) ANSI/ASME PTC 19.3-1974 (R2004). This standard is also 
referenced as ANSI Z21.47-2021, and it specifies thermocouple 
requirements for when testing gas-fired CWAFs.
    Copies of ANSI Z21.47-2021, ANSI/ASHRAE 103-2017 and ANSI/ASME PTC 
19.3-1974 (R2004), can be obtained from 25 W 43rd Street, 4th Floor, 
New York, NY 10036, (212) 642-4900, or online at: webstore.ansi.org.
    (5) AHRI 1500-2015. This test standard provides instruction for how 
to test perform fuel oil analysis and for how to calculate flue loss of 
oil-fired CWAFs.
    Copies of AHRI 1500-2015 can be obtained from 2111 Wilson Blvd., 
Suite 500, Arlington, VA 22201, (703) 524-8800, or online at: 
ahrinet.org.
    (6) NFPA 97-2003. This standard is referenced in UL 727-2018, and 
it provides definitions for the terms combustible and noncombustible.
    Copies of NFPA 97-2003 can be obtained form 1 Batterymarch Park, 
Quincy, MA 02169-7471, (617) 770-3000 or by going online at: 
www.nfpa.org.
    (7) ANSI/ASTM E230/E230M-17. This standard is referenced in UL 727-
2018, and it specifies thermocouple requirements for when testing oil-
fired CWAFs.
    (8) ASTM D396-14a. This standard is referenced in AHRI 1500-2015, 
and it contains general fuel oil requirements.
    (9) ASTM D240-09. This standard is referenced in AHRI 1500-2015, 
and it contains fuel oil heating value requirements.
    (10) ASTM D4809-09a. This standard is referenced in AHRI 1500-2015, 
and it contains fuel oil hydrogen and carbon content requirements.
    (11) ASTM D5291-10. This standard is referenced in AHRI 1500-2015, 
and it contains fuel oil density requirements.
    Copies of ANSI/ASTM E230/E230M-17, ASTM D240-09, ASTM D396-14a, 
ASTM D4809-09a, and ASTM D5291-10, can be obtained from 100 Barr Harbor 
Drive, P.O. Box C700, West Conshohocken, PA 19428, (877) 909-2786 or by 
going online at: www.astm.org.

V. Public Participation

A. Participation in the Webinar

    The time and date of the webinar meeting are listed in the DATES 
section at the beginning of this document. If no participants register 
for the webinar, it will be cancelled. Webinar registration 
information, participant instructions, and information about the 
capabilities available to webinar participants will be published on 
DOE's website: www1.eere.energy.gov/buildings/appliance_standards/standards.aspx?productid=49&action=viewlive Participants are 
responsible for ensuring their systems are compatible with the webinar 
software.

B. Procedure for Submitting Prepared General Statements for 
Distribution

    Any person who has an interest in the topics addressed in this 
proposed rule, or who is 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 webinar. Such persons may submit to 
<a href="/cdn-cgi/l/email-protection#e7a697978b8e86898482b49386898386958394b6928294938e888994a78282c9838882c9808891"><span class="__cf_email__" data-cfemail="f4b58484989d959a9791a780959a9095869087a5819187809d9b9a87b49191da909b91da939b82">[email protected]</span></a>. Persons who wish to speak 
should include with their request a computer file in WordPerfect, 
Microsoft Word, PDF, 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.
    Persons requesting to speak should briefly describe the nature of 
their interest in this rulemaking and provide a telephone number for 
contact. DOE requests persons selected to make an oral presentation to 
submit an advance copy of their statements at least two weeks before 
the webinar. At its discretion, DOE may permit persons who cannot 
supply an advance copy of their statement to participate, if those 
persons have made advance alternative arrangements with the Building 
Technologies Office. As necessary, requests to give an oral 
presentation should ask for such alternative arrangements.

C. Conduct of the Webinar

    DOE will designate a DOE official to preside at the webinar/public 
meeting and may also use a professional facilitator to aid discussion. 
The meeting will not be a judicial or evidentiary-type public hearing, 
but DOE will conduct it in accordance with section 336 of EPCA (42 
U.S.C. 6306). A court reporter will be present to record the 
proceedings and prepare a transcript. DOE reserves the right to 
schedule the order of presentations and to establish the procedures 
governing the conduct of the webinar/public meeting. There shall not be 
discussion of proprietary information, costs or prices, market share, 
or other commercial matters regulated by U.S. anti-trust laws. After 
the webinar/public meeting and until the end of the comment period, 
interested parties may submit further comments on the proceedings and 
any aspect of the rulemaking.
    The webinar will be conducted in an informal, conference style. DOE 
will present a general overview of the topics addressed in this 
rulemaking, allow

[[Page 10747]]

time for prepared general statements by participants, and encourage all 
interested parties to share their views on issues affecting this 
rulemaking. Each participant will be allowed to make a general 
statement (within time limits determined by DOE), before the discussion 
of specific topics. DOE will permit, as time permits, other 
participants to comment briefly on any general statements.
    At the end of all prepared statements on a topic, DOE will permit 
participants to clarify their statements briefly. Participants should 
be prepared to answer questions by DOE and by other participants 
concerning these issues. DOE representatives may also ask questions of 
participants concerning other matters relevant to this rulemaking. The 
official conducting the webinar/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 the above procedures that may be needed for the proper 
conduct of the webinar/public meeting.
    A transcript of the webinar will be included in the docket, which 
can be viewed as described in the Docket section at the beginning of 
this document. In addition, any person may buy a copy of the transcript 
from the transcribing reporter.

D. Participation in the Webinar

    DOE will accept comments, data, and information regarding this 
proposed rule no later than the date provided in the DATES section at 
the beginning of this proposed rule. Interested parties may submit 
comments using any of the methods described in the ADDRESSES section at 
the beginning of this document.
    Submitting comments via www.regulations.gov. The 
www.regulations.gov web page will require you to provide your name and 
contact information. Your contact information will be viewable to DOE 
Building Technologies staff only. Your contact information will not be 
publicly viewable except for your first and last names, organization 
name (if any), and submitter representative name (if any). If your 
comment is not processed properly because of technical difficulties, 
DOE will use this information to contact you. If DOE cannot read your 
comment due to technical difficulties and cannot contact you for 
clarification, DOE may not be able to consider your comment.
    However, your contact information will be publicly viewable if you 
include it in the comment or in any documents attached to your comment. 
Any information that you do not want to be publicly viewable should not 
be included in your comment, nor in any document attached to your 
comment. Persons viewing comments will see only first and last names, 
organization names, correspondence containing comments, and any 
documents submitted with the comments.
    Do not submit to www.regulations.gov information for which 
disclosure is restricted by statute, such as trade secrets and 
commercial or financial information (hereinafter referred to as 
Confidential Business Information (``CBI'')). Comments submitted 
through www.regulations.gov cannot be claimed as CBI. Comments received 
through the website will waive any CBI claims for the information 
submitted. For information on submitting CBI, see the Confidential 
Business Information section.
    DOE processes submissions made through www.regulations.gov before 
posting. Normally, comments will be posted within a few days of being 
submitted. However, if large volumes of comments are being processed 
simultaneously, your comment may not be viewable for up to several 
weeks. Please keep the comment tracking number that www.regulations.gov 
provides after you have successfully uploaded your comment.
    Submitting comments via email. Comments and documents submitted via 
email also will be posted to www.regulations.gov. If you do not want 
your personal contact information to be publicly viewable, do not 
include it in your comment or any accompanying documents. Instead, 
provide your contact information on a cover letter. Include your first 
and last names, email address, telephone number, and optional mailing 
address. The cover letter will not be publicly viewable as long as it 
does not include any comments.
    Include contact information each time you submit comments, data, 
documents, and other information to DOE. No faxes will be accepted.
    Comments, data, and other information submitted to DOE 
electronically should be provided in PDF (preferred), Microsoft Word or 
Excel, or text (ASCII) file format. Provide documents that are not 
secured, written in English and free of any defects or viruses. 
Documents should not contain special characters or any form of 
encryption and, if possible, they should carry the electronic signature 
of the author.
    Campaign form letters. Please submit campaign form letters by the 
originating organization in batches of between 50 to 500 form letters 
per PDF or as one form letter with a list of supporters' names compiled 
into one or more PDFs. This reduces comment processing and posting 
time.
    Confidential Business Information. Pursuant 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 via 
email two well-marked copies: One copy of the document marked 
confidential including all the information believed to be confidential, 
and one copy of the document marked non-confidential with the 
information believed to be confidential deleted. DOE will make its own 
determination about the confidential status of the information and 
treat it according to its determination.
    It is DOE's policy that all comments may be included in the public 
docket, without change and as received, including any personal 
information provided in the comments (except information deemed to be 
exempt from public disclosure).

E. Issues on Which DOE Seeks Comment

    Although DOE welcomes comments on any aspect of this proposal, DOE 
is particularly interested in receiving comments and views of 
interested parties concerning the following issues:
    (1) DOE seeks comment on its tentative conclusion that NFPA 97M is 
an outdated standard that has been superseded by NFPA 97-2003. DOE 
seeks comment on its proposal to incorporate by reference NFPA 97-2003 
in 10 CFR part 431, subpart D.
    (2) DOE seeks comment on its proposal to adopt the optional method 
specified in AHRI 1500-2015 that allows for calculating CO<INF>2</INF> 
using a measured O<INF>2</INF> value. DOE also seeks comment on its 
proposal to establishestablish section 3 of appendix A (i.e., an update 
of 10 CFR 431.76(d) of the current DOE test procedure) to accommodate 
the option to calculate CO<INF>2</INF> using a measured O<INF>2</INF> 
value.
    (3) DOE seeks comment on whether the option provided in Section 
5.4a of ANSI Z21.47-2021 to use test gas H when performing the three 
burner characteristics tests would impact the representativeness or 
burden of the thermal efficiency test.
    (4) DOE seeks comment on its proposal to establish a new test 
procedure (i.e., appendix B) and metric (i.e., TE2) for CWAFs, which 
would generally adopt the same changes proposed for the current test 
procedure at appendix A and account for flue losses in the same manner 
as the current

[[Page 10748]]

TE metric, but would additionally account for jacket losses and part 
load operation.
    (5) DOE seeks comment on its proposal to require jacket loss be 
measured when testing CWAFs designed for outdoor installation and 
designed for indoor installation within an unheated space when 
determining TE2 pursuant to newly proposed appendix B, and on its 
proposed method for measuring jacket loss. DOE also seeks comment on 
its proposal that jacket loss for CWAFs intended for indoor 
installation within a heated space would be assumed to be zero, and on 
its proposed jacket loss factors for CWAFs designed for outdoor 
installation and designed for indoor installation within an unheated 
space.
    (6) DOE seeks comment on its proposal to add a part-load test 
procedure to be incorporated into the newly proposed TE2 metric. DOE 
also seeks comment on its proposal to calculate TE2 by averaging 
performance at the maximum and minimum fire rate and seeks and any 
related data. DOE also requests comment on alternate weighting values, 
including those discussed, that may be more nationally representative 
of an average use, along with any relevant data.
    (7) DOE seeks comment on its proposal to provide instructions in 
the DOE test procedure for testing units with multiple vent hoods.
    (8) DOE seeks comment on its assumption that the amount (i.e., mass 
flow) of flue exhaust exiting each vent hood is proportional to the 
size of the vent hood. Furthermore, DOE seeks comment on its proposal 
to compare vent hood outlet face areas to determine vent hood size.
    (9) DOE seeks comment on the proposal to specify in the DOE test 
procedure that when testing gas- and oil-fired CWAFs, the flue gas 
temperatures shall be measured in the vent hood using nine individual 
thermocouples, or if the vent hood is 2 inches or smaller in diameter, 
five thermocouples may optionally be used.
    (10) DOE seeks comment on its proposal to require the calculation 
method specified in Annex I of ANSI Z21.47-2021 be used when 
determining flue loss, and not the nomograph method.
    (11) DOE seeks comment on its understanding of the impact of the 
test procedure proposals in this NOPR, specifically with respect to 
DOE's estimated test costs, and DOE's initial conclusion regarding the 
testing costs associated with the proposed test procedure for TE2 as 
compared to the current test procedure.
    (12) DOE requests comment on the number of small OEMs DOE 
identified. DOE also seeks comment on the potential costs this small 
manufacturer may incur.

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 test procedures, Incorporation by 
reference, and Reporting and recordkeeping requirements.

Signing Authority

    This document of the Department of Energy was signed on February 
11, 2022, by Kelly J. Speakes-Backman, Principal Deputy Assistant 
Secretary, Energy Efficiency and Renewable Energy, pursuant to 
delegated authority from the Secretary of Energy. That document with 
the original signature and date is maintained by DOE. For 
administrative purposes only, and in compliance with requirements of 
the Office of the Federal Register, the undersigned DOE Federal 
Register Liaison Officer has been authorized to sign and submit the 
document in electronic format for publication, as an official document 
of the Department of Energy. This administrative process in no way 
alters the legal effect of this document upon publication in the 
Federal Register.

    Signed in Washington, DC, on February 14, 2022.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE is proposing to amend 
10 CFR part 431 as set forth below:

PART 431--ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND 
INDUSTRIAL EQUIPMENT

0
1. The authority citation for part 431 continues to read as follows:

    Authority: 42 U.S.C. 6291-6317; 28 U.S.C. 2461 note.

0
2. Amend Sec.  431.72 by adding, in alphabetical order, a definition 
for ``Thermal efficiency two'' to read as follows:


Sec.  431.72  Definitions concerning commercial warm air furnaces.

* * * * *
    Thermal efficiency two for a commercial warm air furnace equals 100 
percent minus percent flue loss and jacket loss.
* * * * *
0
3. Revise Sec.  431.75 to read as follows:


Sec.  431.75  Materials incorporated by reference.

    Certain material is incorporated by reference into this subpart 
with the approval of the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other 
than that specified in this section, DOE must publish a document in the 
Federal Register and the material must be available to the public. All 
approved material is available for inspection at DOE, and at the 
National Archives and Records Administration (NARA). Contact DOE at the 
U.S. Department of Energy, Office of Energy Efficiency and Renewable 
Energy, Building Technologies Program, Sixth Floor, 950 L'Enfant Plaza 
SW, Washington, DC 20024, (202) 586-9127, <a href="/cdn-cgi/l/email-protection#4301362a2f272a2d24300326266d272c266d242c35"><span class="__cf_email__" data-cfemail="511324383d35383f36221134347f353e347f363e27">[email protected]</span></a>, https://www.energy.gov/eere/buildings/building-technologies-office. For 
information on the availability of this material at NARA, email: 
<a href="/cdn-cgi/l/email-protection#b1d7c39fd8dfc2c1d4d2c5d8dedff1dfd0c3d09fd6dec7"><span class="__cf_email__" data-cfemail="c8aebae6a1a6bbb8adabbca1a7a688a6a9baa9e6afa7be">[email protected]</span></a>, or go to: www.archives.gov/federal-register/cfr/ibr-locations.html. It may be obtained from the following sources:
    (a) AHRI. Air-Conditioning, Heating, and Refrigeration Institute, 
2111 Wilson Blvd., Suite 500, Arlington, VA 22201, (703) 524-8800, or 
go to: www.ahrinet.org.
    (1) ANSI/AHRI 1500-2015 (``AHRI 1500-2015''), ``Performance Rating 
of Commercial Space Heating Boilers'', approved November 28, 2014; IBR 
approved for appendices A and B to this subpart.
    (2) [Reserved]
    (b) ANSI. American National Standards Institute. 25 W 43rd Street, 
4th Floor, New York, NY 10036. (212) 642-4900 or go to www.ansi.org.
    (1) ANSI Z21.47-2021,``Gas-fired Central Furnaces'', approved April 
21, 2021; IBR approved for appendices A and B to this subpart.
    (2) [Reserved]
    (c) ASHRAE. American Society of Heating, Refrigerating and Air-
Conditioning Engineers Inc., 1791 Tullie Circle NE, Atlanta, Georgia 
30329, (404) 636-8400, or go to: www.ashrae.org.
    (1) ANSI/ASHRAE Standard 103-2017 (``ASHRAE 103-2017''), ``Method 
of Testing for Annual Fuel Utilization Efficiency of Residential 
Central Furnaces and Boilers'', approved June 30, 2017; IBR approved 
for appendices A and B to this subpart.
    (2) [Reserved]

[[Page 10749]]

    (d) ASME. American Society of Mechanical Engineers, Service Center, 
22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007, (973) 882-1170, or go 
to www.asme.org.
    (1) ANSI/ASME PTC 19.3-1974 (R2004) (``ASME PTC 19.3-1974 
(R2004)''), ``Part 3: Temperature Measurement, Instruments and 
Apparatus'', published January 1, 2004; IBR approved for appendices A 
and B to this subpart.
    (2) [Reserved]
    (e) ASTM. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, 
West Conshohocken, PA 19428, (877) 909-2786, or go to www.astm.org/.
    (1) ANSI/ASTM E230/E230M-17 (``ASTM E230/E230M-17''), ``Standard 
Specification for Temperature-Electromotive Force (emf) Tables for 
Standardized Thermocouples'', approved November 1, 2017, IBR approved 
for appendices A and B to this subpart.
    (2) ASTM D240-09, ``Standard Test Method for Heat of Combustion of 
Liquid Hydrocarbon Fuels by Bomb Calorimeter'', approved July 1, 2009; 
IBR approved for appendices A and B to this subpart.
    (3) ASTM D396-14a, ``Standard Specification for Fuel Oils,'' 
approved on October 1, 2014; IBR approved for appendices A and B to 
this subpart.
    (4) ASTM D4809-09a, ``Standard Test Method for Heat of Combustion 
of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)''; 
IBR approved for appendices A and B to this subpart.
    (5) ASTM D5291-10, ``Standard Test Methods for Instrumental 
Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products 
and Lubricants'', approved on May 1, 2010; IBR approved for appendices 
A and B to this subpart.
    (f) NFPA. National Fire Protection Association, 11 Tracy Drive, 
Avon, MA 02322, 1-800-344-3555, or go to www.nfpa.org.
    (1) NFPA 97-2003, ``Standard Glossary of Terms Relating to 
Chimneys, Vents, and Heat-Producing Appliances''; IBR approved for 
appendices A and B to this subpart.
    (2) [Reserved]
    (g) UL. Underwriters Laboratories, Inc., 333 Pfingsten Road, 
Northbrook, IL 60062, (847) 272-8800, or go to: www.ul.com.
    (1) UL 727 (``UL 727-2018''), ``Standard for Safety Oil-Fired 
Central Furnaces'', Tenth Edition, published January 31, 2018; IBR 
approved for appendices A and B to this subpart.
    (2) [Reserved]
0
4. Revise Sec.  431.76 to read as follows:


Sec.  431.76   Uniform test method for the measurement of energy 
efficiency of commercial warm air furnaces.

    (a) Scope. This section prescribes the test requirements used to 
measure the energy efficiency of commercial warm air furnaces with a 
rated maximum input of 225,000 Btu per hour or more.
    (b) Testing and calculations. (1) Thermal efficiency. Test in 
accordance with appendix A to subpart D of this part when making 
representations of thermal efficiency.
    (2) Thermal efficiency two. Test in accordance with appendix B to 
subpart D of this part when making representations of thermal 
efficiency two.
0
5. Add appendix A to subpart D of part 431 to read as follows:

Appendix A to Subpart D of Part 431--Uniform Test Method for the 
Measurement Energy Efficiency of Commercial Warm Air Furnaces (Thermal 
Efficiency)

    Note: On and after [date 360 days following publication of a 
final rule], any representations made with respect to the energy use 
or efficiency of commercial warm air furnaces must be made in 
accordance with the results of testing pursuant to this section. At 
that time, manufacturers must use the relevant procedures specified 
in this appendix, which reference ANSI Z21.47-2021, ASHRAE 103-2017, 
UL 727-2018, or AHRI 1500-2015. On and after [effective date 30 days 
following publication of a final rule] and prior to [date 360 days 
following publication of a final rule], manufacturers must test 
commercial warm air furnaces in accordance with this appendix or 10 
CFR 431.76 (revised as of January 1, 2020). DOE notes that, because 
testing under this section is required as of [date 360 days 
following publication of a final rule], manufacturers may wish to 
begin using this amended test procedure immediately. Any 
representations made with respect to the energy use or efficiency of 
such commercial warm air furnaces must be made in accordance with 
whichever version is selected.
    1. Incorporation by reference. DOE incorporates by reference in 
Sec.  431.75, the entirety of standards AHRI 1500-2015, ANSI Z21.47-
2021, ASHRAE 103-2017, ASME PTC 19.3-1974 (R2004), ASTM E230/E230M-
17, ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, ASTM D5291-10, NFPA 
97-2003, and UL 727-2018. However, for standards ANSI Z21.47-2021, 
ASHRAE 103-2017, UL 727-2018, and AHRI 1500-2015, only the 
enumerated provisions of those documents apply to this appendix, as 
follows:

1.1 ANSI Z21.47-2021

    1.1.1 Sections 5.1, 5.1.4, 5.2, 5.3, 5.4, 5.5, 5.5.1, 5.6, and 
7.2.1 of ANSI Z21.47-2021 as specified in section 2.1 of this 
appendix;
    1.1.2 Section 5.40 as specified in sections 2.1 and 3.1 of this 
appendix; 1.1.3 Section 5.2.8 as specified in section 5.1 of this 
appendix;
    1.1.4 Annex I as specified in section 4.1 of this appendix.

1.2 ASHRAE 103-2017

    1.2.1 Sections 7.2.2.4, 7.8, and 9.2 of ASHRAE 103-2017 as 
specified in section 3.2 of this appendix;
    1.2.2 Figure 10 of ASHRAE 103-2017 as specified in section 2.3.1 
of this appendix.
    1.2.3 Sections 11.3.7.1 and 11.3.7.2 of ASHRAE 103-2017 as 
specified in section 5.1 of this appendix.

1.3 UL 727-2018

    1.3.1 Sections 2, 3, 37, 38 and 39, 40, 40.6, 41, 42, 43.2, 44, 
45, and 46 of UL 727-2018 as specified in section 2.2 of this 
appendix;
    1.3.2 Figure 40.3 of UL 727-2018 as specified in section 3.1 of 
this appendix.

1.4 AHRI 1500-2015

    1.4.1 Section C3.2.1.1 of AHRI 1500-2015 as specified in section 
2.2 of this appendix; 1.4.2 Sections C7.2.4, C7.2.5, and C7.2.6.2 of 
the AHRI 1500-2015of section 4.2 of this appendix.
    2. Test set-up and Testing. Where this section prescribes use of 
ANSI Z21.47-2021 or UL 727-2018, perform only the procedures 
pertinent to the measurement of the steady-state efficiency, as 
specified in this section.
    2.1 Gas-fired commercial warm air furnaces. The test set-up, 
including flue requirement, instrumentation, test conditions, and 
measurements for determining thermal efficiency are as specified in 
section 2.3 of this appendix, and the following sections of ANSI 
Z21.47-2021: 5.1 (General, including ASME PTC 19.3-1974 (R2004) as 
referenced in Section 5.1.4), 5.2 (Basic test arrangements), 5.3 
(Test ducts and plenums), 5.4 (Test gases), 5.5 (Test pressures and 
burner adjustments), 5.6 (Static pressure and air flow adjustments), 
5.40 (Thermal efficiency), and 7.2.1 (Basic test arrangements for 
direct vent central furnaces). If section 2.3 of this appendix and 
ANSI Z21.47-2021 have conflicting provisions (e.g., the number of 
thermocouples that should be used when testing units with vent hoods 
two inches in diameters or smaller), follow the provisions in 
section 2.3. The thermal efficiency test must be conducted only at 
the normal inlet test pressure, as specified in Section 5.5.1 of 
ANSI Z21.47-2021, and at the maximum hourly Btu input rating 
specified by the manufacturer for the product being tested.
    2.2 Oil-fired commercial warm air furnaces. The test setup, 
including flue requirement, instrumentation, test conditions, and 
measurement for measuring thermal efficiency is as specified in 
section 2.3 of this appendix and the following sections of UL 727-
2018: 2 (Units of Measurement), 3 (Glossary, except that the 
definitions for combustible and non-combustible in Sections 3.11 and 
3.27 shall be as referenced in NFPA 97-2003), 37 (General), 38 and 
39 (Test Installation), 40 (Instrumentation, except 40.4 and 40.6.2 
through 40.6.7 which are not required for the thermal efficiency 
test, and including ASTM E230/E230M-17 as referenced in Sections 
40.6), 41 (Initial Test Conditions), 42 (Combustion Test--Burner and 
Furnace), 43.2 (Operation Tests), 44 (Limit Control

[[Page 10750]]

Cutout Test), 45 (Continuity of Operation Test), and 46 (Air Flow, 
Downflow or Horizontal Furnace Test). If section 2.3 of this 
appendix and UL 727 have conflicting provisions (e.g., the number of 
thermocouples that should be used when testing units with vent hoods 
two inches in diameters or smaller), follow the provisions in 
section 2.3 of this appendix. Conduct a fuel oil analysis for 
heating value, hydrogen content, carbon content, pounds per gallon, 
and American Petroleum Institute (API) gravity as specified in 
Section C3.2.1.1 of AHRI 1500-2015, including the applicable 
provisions of ASTM D240-09, ASTM D4809-09a, ASTM D5291-10, and ASTM 
D396-14a, as referenced. The steady-state combustion conditions, 
specified in Section 42.1 of UL 727-2018, are attained when 
variations of not more than 5 [deg]F in the measured flue gas 
temperature occur for three consecutive readings taken 15 minutes 
apart.
    2.3 Additional test set up requirements for gas-fired and oil-
fired commercial warm air furnaces
    2.3.1 Thermocouple setup for gas and oil-fired commercial warm 
air furnaces with flue vents that are two inches in diameter or 
smaller. For units with vent hoods (i.e., flue outlet hoods) two 
inches in diameter or smaller, the flue gas temperatures may 
optionally be measured using five individual thermocouples, instead 
of nine thermocouples.
    2.3.2 Procedure for flue gas measurements when testing units 
with multiple vent hoods. For units that have multiple vent hoods 
record flue gas measurements (e.g., flue gas temperature, 
CO<INF>2</INF> in the flue gasses) separately for each individual 
vent hood and calculate a weighted-average value based on the 
readings of all vent hoods. To determine the weighted average for 
each measurement, first calculate the face area of each vent hood. 
Then multiply the ratio of each individual vent hood's face area to 
the total face area of all vent hoods (i.e., the face area of each 
individual vent hood divided by the total vent hood area) by that 
vent hood's respective component measurement and the sum of all of 
the products for all of the vent hoods to determine the weighted-
average values. Use the weighted-average values to determine flue 
loss, and whether equilibrium conditions are met before the official 
test period.
    3. Additional test measurements
    3.1 Determination of flue CO<INF>2</INF> (carbon dioxide) or 
O<INF>2</INF> (oxygen) for oil-fired commercial warm air furnaces. 
In addition to the flue temperature measurement specified in Section 
40.6.8 of UL 727-2018, locate one or two sampling tubes within six 
inches downstream from the flue temperature probe (as indicated on 
Figure 40.3 of UL 727-2018). If an open end tube is used, it must 
project into the flue one-third of the chimney connector diameter. 
If other methods of sampling the flue gas are used place the 
sampling tube so as to obtain an average sample. There must be no 
air leak between the temperature probe and the sampling tube 
location. Collect the flue gas sample at the same time the flue gas 
temperature is recorded. The CO<INF>2</INF> or O<INF>2</INF> 
concentration of the flue gas must be as specified by the 
manufacturer for the product being tested, with a tolerance of 
<plus-minus>0.1 percent. Determine the flue CO<INF>2</INF> or 
O<INF>2</INF> using an instrument with a reading error no greater 
than <plus-minus>0.1 percent.
    3.2 Procedure for the measurement of condensate for a gas-fired 
condensing commercial warm air furnace. The test procedure for the 
measurement of the condensate from the flue gas under steady-state 
operation must be conducted as specified in Sections 7.2.2.4, 7.8, 
and 9.2 of ASHRAE 103-2017 under the maximum rated input conditions. 
This condensate measurement must be conducted for an additional 30 
minutes of steady-state operation after completion of the steady-
state thermal efficiency test specified in Section 2.1 of this 
appendix.
    4. Calculation of thermal efficiency
    4.1 Gas-fired commercial warm air furnaces. Use the calculation 
procedure specified in Section 5.40, Thermal efficiency, of ANSI 
Z21.47-2021. When determining the flue loss that is used in the 
calculation of thermal efficiency, the calculation method specified 
in Annex I shall be used.
    4.2 Oil-fired commercial warm air furnaces. Calculate the 
percent flue loss (in percent of heat input rate) by following the 
procedure specified in Sections C7.2.4, C7.2.5, and C7.2.6.2 of the 
AHRI 1500-2015. The thermal efficiency must be calculated as: 
Thermal Efficiency (percent) = 100 percent - flue loss (in percent).
    5. Procedure for the calculation of the additional heat gain and 
heat loss, and adjustment to the thermal efficiency, for a 
condensing commercial warm air furnace.
    5.1 Calculate the latent heat gain from the condensation of the 
water vapor in the flue gas, and calculate heat loss due to the flue 
condensate down the drain, as specified in Sections 11.3.7.1 and 
11.3.7.2 of ASHRAE 103-2017, with the exception that in the equation 
for the heat loss due to hot condensate flowing down the drain in 
Section 11.3.7.2, the assumed indoor temperature of 70 [deg]F and 
the temperature term TOA must be replaced by the measured room 
temperature as specified in Section 5.2.8 of ANSI Z21.47-2021.
    5.2 Adjustment to the thermal efficiency for condensing 
furnaces. Adjust the thermal efficiency as calculated in section 4.1 
of this appendix by adding the latent gain, expressed in percent, 
from the condensation of the water vapor in the flue gas, and 
subtracting the heat loss (due to the flue condensate down the 
drain), also expressed in percent, both as calculated in section 5.1 
of this appendix, to obtain the thermal efficiency of a condensing 
furnace.
0
6. Add appendix B to subpart D of part 431 to read as follows:

Appendix B to Subpart D of Part 431-Uniform Test Method for the 
Measurement Energy Efficiency of Commercial Warm Air Furnaces (Thermal 
Efficiency Two)

    Note: Representations with respect to energy use or efficiency 
of this equipment, including compliance certifications, must be made 
in terms of thermal efficiency (TE), as determined by the test 
procedure specified in appendix A to this subpart. In addition, 
manufacturers may optionally make representations of energy use or 
efficiency of this equipment using thermal efficiency 2 (TE2) as 
determined using this appendix [on or after effective date 30 days 
after publication of final rule].
    1. Incorporation by Reference. DOE incorporates by reference in 
Sec.  431.75, the entirety of standards AHRI 1500-2015, ANSI Z21.47-
2021, ASHRAE 103-2017, ASME PTC 19.3-1974 (R2004), ASTM E230/E230M-
17, ASTM D240-09, ASTM D396-14a, ASTM D4809-09a, ASTM D5291-10, NFPA 
97-2003, and UL 727-2018. However, for standards ANSI Z21.47-2021, 
ASHRAE 103-2017, UL 727-2018, and AHRI 1500-2015, only the 
enumerated provisions of those documents apply to this appendix, as 
follows:

1.1 ANSI Z21.47-2021

    1.1 Sections 5.1, 5.1.4, 5.2, 5.3, 5.4, 5.5, 5.5.1, 5.6, and 
7.2.1 of ANSI Z21.47-2021 as specified in section 2.1 of appendix A 
to this subpart;
    1.1.2 Section 5.40 as specified in sections 2.1 and 3.1 of 
appendix A to this subpart;
    1.1.3 Section 5.2.8 as specified in section 5.1 of appendix A to 
this subpart;
    1.1.4 Annex I as specified in section 4 of appendix A to this 
subpart;
    1.1.5 Annex J as specified in sections 2.2 and 2.6 of this 
appendix.

1.2 ASHRAE 103-2017

    1.2.1 Sections 7.2.2.4, 7.8, and 9.2 of ASHRAE 103-2017 as 
specified in section 3.2 of appendix A to this subpart;
    1.2.2 Figure 10 of ASHRAE 103-2017 as specified in section 2.3.1 
of appendix A to this subpart.
    1.2.3 Sections 11.3.7.1 and 11.3.7.2 of ASHRAE 103-2017 as 
specified in section 5.1 of appendix A to this subpart.

1.3 UL 727-2018

    1.3.1 Sections 2, 3, 37, 38 and 39, 40, 40.6, 41, 42, 43.2, 44, 
45, and 46 of UL 727-2018 as specified in section 2.2 of appendix A 
to this subpart;
    1.3.2 Figure 40.3 of UL 727-2018 as specified in section 3.1 of 
appendix A to this subpart.

1.4 AHRI 1500-2015

    1.4.1 Section C3.2.1.1 of AHRI 1500-2015 as specified in section 
2.2 to appendix A of this subpart;
    1.4.2 Sections C7.2.4, C7.2.5, and C7.2.6.2 of the AHRI 1500-
2015 of section 4.2 of appendix A to this subpart.

2. Testing

    2.1 Setup and test the unit according to sections 1 through 5 of 
appendix A to this subpart, while operating the unit at the maximum 
nameplate input rate (i.e., full load). Calculate thermal efficiency 
TE using the procedure specified in sections 4 and 5 of appendix A 
to this subpart.
    2.2 For commercial warm air furnaces that are designed for 
outdoor installation (including but not limited to CWAFs that are 
weatherized, or approved for resistance to wind, rain, or snow), or 
indoor installation

[[Page 10751]]

within an unheated space (i.e., isolated combustion systems), 
determine the jacket loss using Section 5.40 and Annex J of ANSI 
Z21.47-2021 while the unit is operating at the maximum nameplate 
input.
    2.3 For commercial warm air furnaces that are designed only for 
indoor insulation within a heated space, jacket shall be zero. For 
commercial warm air furnaces that are designed for indoor 
installation within a heated or unheated space, multiply the jacket 
loss determined in section 2.2 of this appendix by 1.7. For all 
other commercial warm air furnaces, including commercial warm air 
furnaces that are designed for outdoor installation (including but 
not limited to CWAFs that are weatherized, or approved for 
resistance to wind, rain, or snow), multiply the jacket loss 
determined in section 2.2 of this appendix by 3.3.
    2.4 Subtract the jacket loss determined in section 2.3 of this 
appendix from the TE determined in section 1.1 of this appendix to 
determine the full load efficiency.
    2.5 Setup and test the unit according to sections 1 through 5 of 
appendix A to this subpart, while operating the unit at the 
nameplate minimum input rate (i.e., part load). Calculate TE using 
the procedure specified in sections 4 and 5 of appendix A to this 
subpart.
    2.6 For commercial warm air furnaces that are designed for 
outdoor installation (including but not limited to CWAFs that are 
weatherized, or approved for resistance to wind, rain, or snow), or 
indoor installation within an unheated space (i.e., isolated 
combustion systems), determine the jacket loss using Section 5.40 
and Annex J of ANSI Z21.47-2021 while the unit is operating at the 
minimum nameplate input. Alternatively, the jacket loss determined 
in section 2.2 of this appendix at the maximum nameplate input may 
be used.
    2.7 For commercial warm air furnaces that are designed only for 
indoor insulation within a heated space, jacket shall be zero. For 
commercial warm air furnaces that are designed for indoor 
installation within a heated or unheated space, multiply the jacket 
loss determined in section 2.6 of this appendix by 1.7. For all 
other commercial warm air furnaces, including commercial warm air 
furnaces that are designed for outdoor installation (including but 
not limited to CWAFs that are weatherized, or approved for 
resistance to wind, rain, or snow), multiply the jacket loss 
determined in section 2.6 of this appendix by 3.3.
    2.8 Subtract the jacket loss determined in section 2.7 of this 
appendix from the TE determined in section 2.5 of this appendix to 
determine the part load efficiency.
    2.9 Calculate TE2 by taking the average of the full-load and 
part-load.

[FR Doc. 2022-03484 Filed 2-24-22; 8:45 am]
BILLING CODE 6450-01-P


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