```

[Federal Register Volume 90, Number 11 (Friday, January 17, 2025)]
[Rules and Regulations]
[Pages 5538-5560]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-01002]

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DEPARTMENT OF ENERGY

10 CFR Part 431

[EERE-2022-BT-TP-0019]
RIN 1904-AF08

Energy Conservation Program: Test Procedure for Compressors

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

ACTION: Final rule.

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SUMMARY: The U.S. Department of Energy (``DOE'') is amending the test 
procedure for compressors to correct an error and to ensure that 
pressure ratio is expressed in terms of absolute pressure. DOE is also 
correcting the formula for isentropic efficiency and specific energy 
consumption of the packaged compressor by incorporating a K6 
correction factor to correct for differences in pressure ratio when 
testing at differing elevations. Finally, DOE is amending the 
definition of ``air compressor'' to include a minor clarification and 
revise a typographical error.

DATES: The effective date of this rule is April 2, 2025. The amendments 
will be mandatory for product testing starting July 16, 2025.
    The incorporation by reference of certain publications listed in 
the rule is approved by the Director of the Federal Register on April 
2, 2025.

ADDRESSES: The docket, which includes Federal Register notices, public 
meeting attendee lists and transcripts, 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, not all documents listed in the index may be publicly 
available, such as those containing information that is exempt from 
public disclosure.
    A link to the docket web page can be found at www.regulations.gov/docket/EERE-2022-BT-TP-0019. The docket web page contains instructions 
on how to access all documents, including public comments, in the 
docket.
    For further information on how to review the docket contact the 
Appliance and Equipment Standards Program staff at (202) 287-1445 or by 
email: [email protected].

FOR FURTHER INFORMATION CONTACT: 
    Mr. Jeremy Dommu, U.S. Department of Energy, Office of Energy 
Efficiency and Renewable Energy, Building Technologies Office, EE-2J, 
1000 Independence Avenue SW, Washington, DC 20585-0121. Telephone: 
(202) 586-9870. Email: [email protected].
    Mr. Pete Cochran, U.S. Department of Energy, Office of the General 
Counsel, GC-33, 1000 Independence Avenue SW, Washington, DC 20585-0121. 
Telephone: (202) 586-9496. Email: [email protected].

SUPPLEMENTARY INFORMATION: 
    DOE incorporates by reference the following industry standards into 
title 10 of the Code of Federal Regulation (``CFR'') part 431:
    IEC 60584-1:2013, Thermocouples--Part 1: EMF specifications and 
tolerances, edition 3.0, August 2013 (``IEC 60584-1:2013'').
    IEC 60584-3:2021, Thermocouples--Part 3: Extension and compensating 
cables--Tolerances and identification system, edition 3.0, February 
2021 (``IEC 60584-3:2021'').
    Copies of IEC 60584-1:2013 and IEC 60584-3:2021 may be purchased 
from International Electrotechnical Commission (``IEC'') Central 
Office, 3, rue de Varemb[eacute], Case Postale 131, CH-1211, Geneva, 
Switzerland +41 22 919 02 11, or by going to webstore.iec.ch.
    ISO 1217:2009(E), Displacement compressors--Acceptance tests, 
fourth edition, July 1, 2009 (``ISO 1217:2009(E)'').
    ISO 1217:2009/Amd.1:2016(E), Displacement compressors--Acceptance 
tests (fourth edition, July 1, 2009), AMENDMENT 1: Calculation of 
isentropic efficiency and relationship with specific energy, April 15, 
2016 (``ISO 1217:2009/Amd.1:2016(E)'').
    ISO 5167-1:2022(E), Measurement of fluid flow by means of pressure

[[Page 5539]]

differential devices inserted in circular cross-section conduits 
running full--Part 1: General principles and requirements, third 
edition, June 2022 (``ISO 5167-1:2022(E)'').
    ISO 9300:2022(E), Measurement of gas flow by means of critical flow 
nozzles, third edition, June 2022 (``ISO 9300:2022(E)'').
    Copies of ISO 1217:2009(E), ISO 1217:2009/Amendment 1:2016(E), ISO 
5167-1:2022(E), and ISO 9300:2022(E) may be purchased from 
International Organization for Standardization (``ISO'') at Chemin de 
Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland +41 22 749 01 
11, or by going to www.iso.org.
    See section IV.N of this document for further discussion of these 
standards.

Table of Contents

I. Authority and Background
    A. Authority
    B. Background
II. Synopsis of the Final Rule
III. Discussion
    A. Scope of Applicability
    1. Reciprocating Compressors
    2. Centrifugal Compressors
    3. Compressor Motor Nominal Horsepower
    4. Lubricant-Free Compressors
    5. Brushed Motors
    6. Output Pressure Less Than 75 psig
    7. Integrated Dryers
    B. Updates to Industry Standards
    1. ISO 1217:2009(E) as the Basis for This Test Procedure
    2. Ambient Temperature Range Requirement
    C. Definitions
    1. Multi-Element Air Compressors
    D. Efficiency Metrics
    1. Load Point for Fixed-Speed Compressors
    2. Load Points for Variable-Speed Compressors
    3. Inclusion of Unloaded Operation for Fixed-Speed Compressors
    4. Part-Load Performance of Fixed-Speed Compressors With 
Variable-Airflow Controls
    E. Test Method
    1. K6 Correction Factor
    2. Correction of Pressure Ratio at Full-Load Operating Pressure 
Formula
    3. Tolerances for Measured Energy Efficiency Values
    F. Reporting
    G. Test Procedure Costs and Harmonization
    1. Amendment to Incorporate K6 Correction Factor
    2. Amendment To Update Formula for Pressure Ratio at Full-Load 
Operating Pressure
    3. Amendment to Update Definition of ``Air Compressor''
    4. Harmonization With Industry Standards
    H. Effective and Compliance Dates
    I. Renumbering of Appendix A
IV. Procedural Issues and Regulatory Review
    A. Review Under Executive Orders 12866, 13563, and 14094
    B. Review Under the Regulatory Flexibility Act
    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. Congressional Notification
    N. Description of Materials Incorporated by Reference
V. Approval of the Office of the Secretary

I. Authority and Background

    Compressors are included in the list of ``covered equipment'' (via 
the clause classifying certain types of ``industrial equipment'' as 
``covered equipment'') for which the U.S. Department of Energy 
(``DOE'') is authorized to establish and amend energy conservation 
standards and test procedures. (42 U.S.C. 6311(1)(L), 6311(2)(B)(i), 
and 6312(b)). DOE's test procedures for compressors are currently 
prescribed at subpart T of part 431 of title 10 of the Code of Federal 
Regulations (10 CFR part 431). The following sections discuss DOE's 
authority to establish and amend test procedures for compressors and 
relevant background information regarding DOE's consideration of test 
procedures for this equipment.

A. Authority

    The Energy Policy and Conservation Act, Public Law 94-163, 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, as codified) Title III, Part C of EPCA,\2\ 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. This 
equipment includes compressors, the subject of this document. Under 
EPCA, DOE may include a type of industrial equipment, including 
compressors, as covered equipment if it determines that doing so is 
necessary to carry out the purposes of Part A-1. (42 U.S.C. 6311(1)(L), 
6311(2)(B)(i), and 6312(b)). The purpose of Part A-1 is to improve the 
efficiency of electric motors and pumps and certain other industrial 
equipment to conserve the energy resources of the Nation. (42 U.S.C. 
6312(a)). On November 15, 2016, DOE published a final rule, which 
determined that coverage for compressors is necessary to carry out the 
purposes of Part A-1 of Title III of EPCA. 81 FR 79991. (42 U.S.C. 
6311(1)(L); 42 U.S.C. 6311 (2)(A); 42 U.S.C. 6311 (2)(B)(i))
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    \1\ All references to EPCA in this document refer to the statute 
as amended through the Energy Act of 2020, Public Law 116-260 (Dec. 
27, 2020), which reflect the last statutory amendments that impact 
Parts A and A-1 of EPCA.
    \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(a); 42 U.S.C. 6295(s)), and (2) making other representations about 
the efficiency of that equipment (42 U.S.C. 6314(d)). Similarly, DOE 
must use these test procedures to determine whether the equipment 
complies with relevant standards promulgated under EPCA. (42 U.S.C. 
6316(a); 42 U.S.C. 6295(s))
    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 42 U.S.C. 6316(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).
    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 that reflect energy efficiency, energy use, or estimated annual 
operating cost of a given type of covered equipment during a

[[Page 5540]]

representative average use cycle (as determined by the Secretary) and 
requires that test procedures not be unduly burdensome to conduct. (42 
U.S.C. 6314(a)(2))
    EPCA also requires that, at least once every 7 years, DOE evaluate 
test procedures for each type of covered equipment, including 
compressors, 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))
    In addition, 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. (42 U.S.C. 6314(a)(1)(A)(ii))
    DOE is publishing this final rule in satisfaction of the 7-year 
review requirement specified in EPCA. (42 U.S.C. 6314(b)(1))

B. Background

    DOE's existing test procedure for compressors appears at title 10 
of the Code of Federal Regulations (CFR) part 431, subpart T, appendix 
A--Uniform Test Method for Certain Air Compressors (hereafter 
``appendix A'').
    As stated, DOE published a final rule on November 15, 2016, in 
which DOE determined that coverage of compressors is necessary to carry 
out the purposes of Part A-1 of Title III of EPCA. 81 FR 79991. DOE's 
test procedure for determining compressor energy efficiency of certain 
varieties of compressors was established in a final rule published on 
January 4, 2017 (hereafter, the ``January 2017 Final Rule''). 82 FR 
1052.
    On May 17, 2019, DOE published a notice of petition for rulemaking 
and request for comment regarding the test procedure for compressors in 
response to a petition from Atlas Copco North America (``Atlas 
Copco''). 84 FR 22395. Atlas Copco's petition was received on April 17, 
2019. Atlas Copco requested that DOE amend the compressors test 
procedure to specify that manufacturers could satisfy the test 
procedure requirements by using the industry test method for rotary air 
compressor energy efficiency, ISO 1217:2009(E) ``Displacement 
compressors--Acceptance tests''. In the notice of petition for 
rulemaking, DOE sought comment as to whether to proceed with the 
petition, but took no position at the time regarding the merits of the 
suggested rulemaking or the assertions made by Atlas Copco. 84 FR 
22395.\3\
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    \3\ Associated documents are available in the rulemaking docket 
at www.regulations.gov/docket/EERE-2019-BT-PET-0017.
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    On January 10, 2020, DOE published a final rule for energy 
conservation standards for air compressors (hereafter, the ``January 
2020 ECS Final Rule''). 85 FR 1504. Compliance with the energy 
conservation standards established in the January 2020 ECS Final Rule 
is required for compressors manufactured starting on January 10, 2025. 
10 CFR 431.345.
    On May 6, 2022, DOE issued a Request for Information (``RFI'') for 
a test procedure for compressors to consider whether to amend DOE's 
test procedure for compressors (hereafter, the ``May 2022 RFI''). 87 FR 
27025. To inform interested parties and to facilitate this process, DOE 
identified certain issues associated with the currently applicable test 
procedure on which DOE is interested in receiving comment. On June 6, 
2022, DOE granted a 14-day extension to the public comment period, 
allowing comments to be submitted until June 20, 2022. 87 FR 34220.
    In general, representations of compressor performance must be in 
accordance with the DOE test procedure. (42 U.S.C. 6314(d)). However, 
DOE guidance (issued Dec. 6, 2017; revised Jun. 8, 2018) stated that it 
would discretionarily not enforce this requirement until compliance 
with a standard is required or a labeling requirement is established. 
On May 2, 2022, DOE announced that it was suspending the enforcement 
policy regarding the test procedure for air compressors and removed the 
policy from the DOE enforcement website.
    Following retraction of the enforcement policy and to aid 
manufacturers in understanding DOE's regulatory requirements regarding 
the test procedure and forthcoming energy conservation standards, DOE 
held a ``Compressors Regulations 101'' webinar on May 24, 2022. The 
webinar reviewed testing, rating, certification, and compliance 
responsibilities.\4\
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    \4\ The slide material presented during the webinar has been 
published on DOE's website: www.energy.gov/sites/default/files/2022-05/compressors-101.pdf.
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    On February 13, 2023, DOE published a notice of proposed rulemaking 
and announcement of public meeting for test procedures for compressors 
(hereafter, the ``February 2023 NOPR''). 88 FR 9199. To inform 
interested parties and to facilitate this process, DOE identified 
certain issues associated with the currently applicable test procedure 
on which DOE is interested in receiving comment. On March 22, 2023, DOE 
held a public meeting (hereafter, the ``March 2023 Public Meeting'') to 
obtain stakeholder input regarding the issues and proposed amendments 
raised by the February 2023 NOPR.
    DOE received comments in response to the February 2023 NOPR from 
the interested parties listed in table I.1.

          Table I.1--List of Commenters With Written Submissions in Response to the February 2023 NOPR
----------------------------------------------------------------------------------------------------------------
                                      Reference in this   Comment No. in
           Commenter(s)                  final rule         the docket                Commenter type
----------------------------------------------------------------------------------------------------------------
Compressed Air & Gas Institute....  CAGI................              21  Trade Association.
Saylor-Beall Air Compressors......  Saylor-Beall........              22  Manufacturer.
Sullivan-Palatek, Inc.............  Sullivan-Palatek....              23  Manufacturer.
Kaeser Compressors................  Kaeser Compressors..              24  Manufacturer.
Ingersoll Rand....................  Ingersoll Rand......              25  Manufacturer.
Northwest Energy Efficiency         NEEA & NPCC.........              26  Efficiency Organizations.
 Alliance, and Northwest Power and
 Conservation Council.
Pacific Gas and Electric Company,   CA IOUs.............              27  Utility Companies.
 San Diego Gas and Electric, and
 Southern California Edison.

[[Page 5541]]

 
Appliance Standard Awareness        ASAP, ACEEE, & NRDC.              28  Efficiency Organizations.
 Project, American Council for an
 Energy-Efficient Economy, and
 Natural Resources Defense Council.
----------------------------------------------------------------------------------------------------------------

    A parenthetical reference at the end of a comment quotation or 
paraphrase provides the location of the item in the public record.\5\ 
To the extent that interested parties have provided written comments 
that are substantively consistent with any oral comments provided 
during the March 2023 Public Meeting, DOE cites the written comments 
throughout this final rule. DOE did not identify any oral comments 
provided during the March 2023 Public Meeting that are not 
substantively addressed by written comments.
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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 compressors. (Docket No. EERE-2022-BT-TP-0019, 
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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II. Synopsis of the Final Rule

    In this final rule, DOE is amending subpart T of title 10 of the 
Code of Federal Regulations, part 431 (10 CFR part 431), which contains 
definitions, materials incorporated by reference, and the test 
procedure for determining the energy efficiency of certain varieties of 
compressors, as follows:
    (1) Correct the formula for calculating isentropic efficiency and 
specific energy consumption of the packaged compressor by incorporating 
a K6 correction factor to correct for the change in pressure ratio when 
testing at differing elevations;
    (2) Revise the formula for pressure ratio at full-load operating 
pressure currently in 10 CFR part 431, subpart T to correct a 
typographical error, and to calculate pressure ratio using terms 
expressed in absolute pressure; and
    (3) Modify the current definition of ``air compressor'' to clarify 
that compressors with more than one compression element are still 
within the scope of this test procedure, and to revise the 
typographical error of ``compressor element'' to ``compression 
elements.''
    DOE's 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 Amended Test Procedure
----------------------------------------------------------------------------------------------------------------
  DOE test procedure prior to amendment        Amended test procedure                   Attribution
----------------------------------------------------------------------------------------------------------------
References ISO 1217:2009(E) Annex C       Adds the K6 correction factor    Error correction.
 (excluding sections C.1.2, C.2.1, C.3,    in the formula calculating
 C.4.2.2, C.4.3.1, and C.4.5) for          isentropic efficiency and
 calculating isentropic efficiency and     specific energy consumption of
 specific energy consumption of the        the packaged compressor in
 packaged compressor.                      order to correct for the
                                           change in pressure ratio when
                                           testing at differing
                                           elevations. Incorporates by
                                           reference Annex B, section
                                           B.4.5 of ISO 1217:2009(E).
Pressure ratio at full-load operating     Corrects the pressure ratio at   Error correction.
 pressure formula in 10 CFR part 431,      full-load operating pressure
 subpart T contains an error, as the       formula in 10 CFR part 431,
 wrong formula is presented.               subpart T.
Air Compressor Definition: A compressor   Air Compressor Definition: A     Clarification.
 designed to compress air that has an      compressor designed to
 inlet open to the atmosphere or other     compress air that has an inlet
 source of air, and is made up of a        open to the atmosphere or
 compression element (bare compressor),    other source of air, and is
 driver(s), mechanical equipment to        made up of one or more
 drive the compressor element, and any     compression elements (bare
 ancillary equipment.                      compressors), driver(s),
                                           mechanical equipment to drive
                                           the compression elements, and
                                           any ancillary equipment.
----------------------------------------------------------------------------------------------------------------

    DOE has determined that the amendments described in section III and 
adopted in this document will more accurately comply with the 
requirements that test procedures be reasonably designed to produce 
test results that reflect energy use during a representative average 
use cycle and are not unduly burdensome to conduct. (42 U.S.C. 
6314(a)(2)) The amendments adopted in this final rule will ensure that 
any test for isentropic efficiency and specific energy consumption of a 
packaged compressor performed at any elevation other than 364 ft, or 
during low- or high-pressure weather events, will be correct. As such, 
these amendments will ensure accurate measured/calculated efficiency of 
compressors. DOE has also determined that these amendments will not 
require retesting or recertification solely as a result of DOE's 
adoption of the amendments to the test procedures since the amendment 
aligns the test procedure with existing industry practice. 
Additionally, DOE has determined that the amendments will not increase 
the cost of testing. Discussion of DOE's actions are addressed in 
detail in section III of this document.
    The effective date for the amended test procedures adopted in this 
final rule is 75 days after publication of this document in the Federal 
Register. Representations of energy use or energy efficiency must be 
based on testing in accordance with the amended test procedures 
beginning 180 days after the publication of this final rule.

III. Discussion

    In the following sections, DOE adopts certain amendments to its 
test procedure for compressors. For each amendment, DOE provides 
relevant background information, explains why

[[Page 5542]]

the amendment merits consideration, discusses relevant public comments, 
and adopts an approach.

A. Scope of Applicability

    DOE's test procedure applies to a compressor that meets all of the 
following criteria: is an air compressor; is a rotary compressor; is 
not a liquid ring compressor; is driven by a brushless electric motor; 
is a lubricated compressor; has a full-load operating pressure of 75-
200 pounds per square inch gauge (psig); is not designed and tested to 
the requirements of the American Petroleum Institute Standard 619; has 
full-load actual volume flow rate greater than or equal to 35 cubic 
feet per minute (cfm), or is distributed in commerce with a compressor 
motor nominal horsepower greater than or equal to 10 horsepower (hp); 
and has a full-load actual volume flow rate less than or equal to 1,250 
cfm, or is distributed in commerce with a compressor motor nominal 
horsepower less than or equal to 200 hp. 10 CFR 431.344.
    DOE received comments both supporting and opposing scope changes. 
CAGI, supported by Kaeser Compressors, Ingersoll Rand, Saylor-Beall, 
and Sullivan-Palatek, stated that they support DOE's proposal to 
maintain the current scope of the test procedure. (CAGI, No. 21 at pp. 
1-3; Kaeser Compressors, No. 24 at pp. 3-5; Ingersoll Rand, No. 25 at 
pp. 1-3; Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 
1) On the other hand, NEEA & NPCC, CA IOUs, and ASAP, ACEEE, & NRDC 
encouraged DOE to consider expanding the scope of the test procedure to 
include additional air compressor types. (NEEA & NPCC, No. 26 at pp. 2-
4; CA IOUs, No. 27 at pp. 2-9; ASAP, ACEEE, & NRDC, No. 28 at pp. 1-3)
    As discussed in more detail in the following sections, DOE is not 
amending the scope of the test procedure at this time. DOE may consider 
test procedure scope expansion, including related comments discussed in 
this final rule, in a future test procedure rulemaking.
    DOE responds to specific scope expansion topics in sections III.A.1 
through III.A.7 of this final rule.
1. Reciprocating Compressors
    As stated in section III.A of this document, the current test 
procedure for compressors applies to rotary compressors (and, 
therefore, does not apply to reciprocating compressors). 10 CFR 
431.344. In the February 2023 NOPR, DOE proposed to continue excluding 
reciprocating compressors from the scope of the test procedure. 88 FR 
9199, 9203. DOE stated that it will continue reviewing potential test 
procedures for reciprocating compressors, including existing test 
methods, and may consider expanding the scope of the test procedure to 
include these compressors in a future test procedure rulemaking. Id. 
DOE also asked for comment regarding its proposal to not include 
reciprocating compressors within the scope of test procedure 
applicability. Id.
    In response to the February 2023 NOPR, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all expressed 
support for the DOE proposal to exclude reciprocating compressors from 
the scope of test procedure applicability. (CAGI, No. 21 at p. 1; 
Kaeser Compressors, No. 24 at p. 3; Ingersoll Rand, No. 25 at p. 1; 
Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    However, in response to the request for comment, NEEA & NPCC 
recommended that DOE modify the proposed test procedure or develop a 
new test procedure for testing both one- and three-phase reciprocating 
compressors because ISO 1217:2009(E) contains a commonly used test 
procedure for rating reciprocating compressors among manufacturers. 
However, NEEA & NPCC commented that the reasons discussed in the 
February 2023 NOPR (88 FR 9199, 9202) for DOE not using ISO 
1217:2009(E), as currently written, as the test method for 
reciprocating compressors are reasonable. NEEA & NPCC also stated that, 
by establishing a test procedure for reciprocating compressors, DOE is 
ensuring consistent representation of efficiency in this market and 
creating a path for industry stakeholders to gather data on this 
equipment type that would better inform future rulemakings. (NEEA & 
NPCC, No. 26 at pp. 2-3) ASAP, ACEEE, & NRDC agreed with this point and 
added that, given the significant potential energy savings for 
reciprocating compressors, DOE should consider the inclusion of 
reciprocating compressors within the test procedure scope. ASAP, ACEEE, 
& NRDC also stated that this would make it easier for DOE to pursue 
future energy conservation standards for reciprocating compressors and 
could provide helpful efficiency data to support voluntary programs. 
(ASAP, ACEEE, & NRDC, No. 28 at pp. 2-3)
    DOE agrees that there could be benefits to including reciprocating 
compressors within the scope of the test procedure. DOE also agrees 
that the test method in ISO 1217:2009(E) might be appropriate for some 
reciprocating compressors but inappropriate for others, as there are a 
wide range of intended duty cycles for reciprocating compressors.
    DOE is continuing to exclude reciprocating compressors from the 
scope of the compressors test procedure. DOE will continue reviewing 
potential test procedures for reciprocating compressors, including 
existing test methods, and may consider expanding the scope of the test 
procedure to include reciprocating compressors in a future test 
procedure rulemaking.
2. Centrifugal Compressors
    As stated in section III.A of this document, the current test 
procedure for compressors applies to rotary positive displacement 
compressors (and therefore does not apply to centrifugal air 
compressors). 10 CFR 431.344. In the February 2023 NOPR, DOE proposed 
to continue excluding centrifugal compressors from the scope of the 
test procedure. 88 FR 9199, 9203. DOE stated that it will continue to 
review and consider potential test methods for centrifugal compressors 
and may consider developing test procedures for centrifugal compressors 
as a part of a future rulemaking process. Id. DOE also asked for 
comment regarding its proposal to not include centrifugal compressors 
within the scope of test procedure applicability and regarding whether 
dynamic compressor varieties other than centrifugal compete with the 
air compressor categories discussed in the February 2023 NOPR. Id.
    In response to the request for comment in the February 2023 NOPR, 
CAGI, Kaeser Compressors, Ingersoll Rand, Saylor-Beall, and Sullivan-
Palatek all expressed support for DOE's proposal to exclude centrifugal 
compressors from the scope of test procedure applicability. (CAGI, No. 
21 at p. 2; Kaeser Compressors, No. 24 at p. 3; Ingersoll Rand, No. 25 
at p. 1; Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 
1) Additionally, in response to the request for comment regarding 
clarification on ``dynamic'' versus ``centrifugal'' compressors, CAGI, 
Kaeser Compressors, Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek 
all supported the position that centrifugal compressors are the only 
form of dynamic compressor that competes with the air compressor 
categories discussed in the February 2023 NOPR. (CAGI, No. 21 at p. 2; 
Kaeser Compressors, No. 24 at p. 3; Ingersoll Rand, No. 25 at p. 2; 
Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    NEEA & NPCC also recommended that DOE consider a separate future 
test

[[Page 5543]]

procedure rulemaking for centrifugal compressors, which would create a 
path for expanding the current test procedure scope to rotary 
compressors up to 500 hp. NEEA & NPCC commented that centrifugal 
compressors make up a small market share but represent 18 percent of 
annual energy consumption for industrial compressors, and are typically 
above 200 hp. NEEA & NPCC also stated that rotary and centrifugal 
compressors from 200 hp to 500 hp represent 25 percent of total 
commercial and industrial compressor energy consumption. NEEA & NPCC 
stated that ISO 5389 is an industry-accepted test procedure for 
centrifugal compressors and recommended this as an option for a future 
centrifugal compressor test procedure rulemaking. NEEA & NPCC also 
stated that there is little overlap in the applications that would use 
a centrifugal compressor instead of a rotary compressor because 
centrifugal compressors are more expensive and are used for specific 
applications that require clean air. (NEEA & NPCC, No. 26 at pp. 3-4)
    CA IOUs recommended DOE expand the scope of this test procedure to 
cover centrifugal compressors. CA IOUs stated that dynamic air 
compressors account for approximately 18 percent of total industrial 
air compressor national energy consumption. CA IOUs also stated that 
the inclusion of dynamic compressors would give end users more data to 
compare with and that these compressors provide oil- and particulate-
free air, which would allow them to compete with regulated and large 
positive displacement rotary compressors in certain applications. (CA 
IOUs, No. 27 at pp. 7-9) ASAP, ACEEE, & NRDC also encouraged DOE to 
include centrifugal compressors in the scope of this test procedure 
final rule due to the significance of their energy usage and the fact 
that centrifugal compressors may compete with large rotary positive 
displacement compressors. ASAP, ACEEE, & NRDC added that ISO 5389, the 
industry test procedure for dynamic compressors, could potentially 
serve as the basis of the test procedure. (ASAP, ACEEE, & NRDC, No. 28 
at p. 3)
    It is true that centrifugal compressors can compete with large 
rotary positive displacement compressors, as stated by commenters. (CA 
IOUs, No. 27 at pp. 8-9; ASAP, ACEEE, & NRDC, No. 28 at p. 3) DOE 
discussed the potential for competition between these categories in the 
January 2017 Final Rule. 82 FR 1052, 1061-1063. Competition between 
these categories is considerable above 200 hp, and this reasoning was 
used to set the upper bound of the compressor test procedure motor 
nominal horsepower at 200 hp. 82 FR 1052, 1062. As discussed in section 
III.A.3 of this final rule, DOE is maintaining this upper bound on 
compressor motor nominal horsepower in the test procedure. This ensures 
that there is not considerable competition between unregulated 
centrifugal compressors and regulated positive displacement rotary 
compressors within the scope of the DOE compressors test procedure.
    DOE has not yet determined a test procedure for centrifugal 
compressors that would produce test results that reflect efficiency 
during a representative average use cycle and that would not be unduly 
burdensome to conduct. (42 U.S.C. 6314(a)(2)) Due to the reasons 
discussed in the February 2023 NOPR and previous paragraphs, DOE is not 
expanding the scope of this test procedure to include centrifugal 
compressors. DOE continues to review and consider potential methods for 
centrifugal compressors and may consider developing test procedures for 
centrifugal compressors as part of a future rulemaking process.
3. Compressor Motor Nominal Horsepower
    As stated in section III.A of this document, the current test 
procedure for compressors applies to compressors that have a full-load 
operating pressure of 75 to 200 psig (inclusive) and either (1) a full-
load actual volume flow rate of 35 to 1,250 cfm (inclusive) or (2) 
compressor motor nominal horsepower of 10 to 200 hp (inclusive). 10 CFR 
431.344. In the February 2023 NOPR, DOE tentatively determined that the 
same burden concerns as discussed in the January 2017 Final Rule would 
continue to exist for the current compressor market. 88 FR 9199, 9203. 
These include a small number of shipments of units greater than 200 hp 
and the potential for competitive disadvantage for rotary positive 
displacement compressors that compete with centrifugal compressors. Id. 
Therefore, DOE did not propose any changes to the current horsepower 
range of 10 to 200 hp for the existing test procedure in the February 
2023 NOPR. Id. DOE asked for comment regarding the determination to not 
include compressors with a horsepower rating above 200 hp within the 
scope of test procedure applicability. Id.
    In response to the February 2023 NOPR, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all expressed 
support for the DOE proposal to not include compressors with a 
horsepower rating above 200 hp within the scope of test procedure 
applicability. (CAGI, No. 21 at p. 2; Kaeser Compressors, No. 24 at pp. 
3-4; Ingersoll Rand, No. 25 at p. 2; Saylor-Beall, No. 22 at p. 1; 
Sullivan-Palatek, No. 23 at p. 1)
    Kaeser Compressors encouraged DOE to investigate increasing the 
maximum horsepower above 200 hp to 500 hp in a future rulemaking. 
(Kaeser Compressors, No. 24 at p. 2) NEEA & NPCC recommended that DOE 
consider a separate future test procedure rulemaking for centrifugal 
compressors, which would create a path for expanding the current test 
procedure scope to rotary compressors up to 500 hp. NEEA & NPCC also 
stated that rotary and centrifugal compressors from 200 hp to 500 hp 
represent 25 percent of total commercial and industrial compressor 
energy consumption. (NEEA & NPCC, No. 26 at pp. 3-4)
    CA IOUs recommended that DOE expand the scope of the test procedure 
to cover large (201-500 hp) rotary positive displacement air 
compressors. CA IOUs stated that all compressor types in this size 
range consume 29 percent of total industrial air compressor energy, and 
that increasing the scope of the test procedure would support the goal 
of fully evaluating the cost-effectiveness, technological feasibility, 
and economically justified savings opportunities for end users. CA IOUs 
also stated that air compressor manufacturers voluntarily provide CAGI 
data sheets for large and oil-free rotary positive displacement air 
compressors, therefore the additional test burden of covering 
compressors with motors operating at 201-500 hp is limited. CA IOUs 
provided data showing that there is a wide range of isentropic 
efficiencies for rotary positive displacement compressors with motor 
nominal power greater than 200 hp. Finally, CA IOUs provided data 
indicating that centrifugal compressors likely compete with fixed-speed 
rotary positive displacement compressors to provide baseload, but they 
do not likely compete with variable-speed rotary positive displacement 
compressors providing low part load. (CA IOUs, No. 27 at pp. 2-7)
    ASAP, ACEEE, & NRDC also encouraged DOE to expand the scope of the 
test procedure to cover rotary positive displacement air compressors 
greater than 200 hp. ASAP, ACEEE, & NRDC disagreed with DOE's rationale 
for excluding rotary compressors greater than 200 hp for several 
reasons. First, ASAP, ACEEE, & NRDC indicated that CAGI performance 
data is already available for many of these larger models. Second, 
ASAP, ACEEE, & NRDC acknowledged that larger

[[Page 5544]]

compressors have lower shipment numbers, but they indicated that DOE 
has recently expanded the scope of the electric motors test procedure 
to 750 hp and stated that very large electric motors are also often 
low-volume, custom products. Third, ASAP, ACEEE, & NRDC stated that 
most compressor manufacturers make both in-scope rotary compressors and 
out-of-scope compressors, so it is unclear whether certain 
manufacturers would be disadvantaged by inclusion of larger rotary 
compressors. Finally, ASAP, ACEEE, & NRDC stated that DOE should 
consider expanding the test procedure scope to currently out-of-scope 
compressor types, such as centrifugal compressors, as this would 
mitigate concerns over disadvantaging certain manufacturers or pushing 
the market towards out-of-scope substitutions. (ASAP, ACEEE, & NRDC, 
No. 28 at pp. 1-2)
    DOE recognizes that a considerable amount of the market for 
compressors greater than 200 hp is served by centrifugal compressors. 
As discussed in the January 2017 Final Rule, the inclusion of rotary 
compressors greater than 200 hp could create a competitive disadvantage 
for manufacturers of these compressors, as centrifugal compressors of 
the same horsepower do not have the same testing and representation 
requirements. 82 FR 1052, 1061-1062. DOE concluded at the time that 
this competitive advantage could incentivize users to switch from 
regulated rotary compressors to unregulated centrifugal compressors, 
thus creating a competitive advantage for manufacturers of unregulated 
centrifugal compressors. Id. Although commenters have indicated that 
these categories compete in only a subset of the market and that some 
manufacturers make both regulated and unregulated compressors, the same 
competitive issues still largely exist today.
    Although ASAP, ACEEE, & NRDC have suggested that DOE can mitigate 
the concerns over competition by covering both rotary positive 
displacement and centrifugal compressors over 200 hp in the test 
procedure scope (ASAP, ACEEE, & NRDC, No. 28 at pp. 1-2), section 
III.A.2 of this final rule discusses that DOE is continuing to exclude 
centrifugal compressors from the scope of the test procedure at this 
time. As a result, in order to ensure that there is not considerable 
competition between unregulated centrifugal compressors and regulated 
positive displacement rotary compressors, DOE is also continuing to 
exclude rotary positive displacement compressors over 200 hp from the 
scope of the test procedure at this time.
    For the reasons discussed in the February 2023 NOPR and the 
previous paragraphs, DOE is maintaining the current horsepower range of 
10 to 200 hp for this test procedure final rule. DOE continues to 
review and consider potential methods for testing positive displacement 
rotary compressors with nominal motor horsepower greater than and less 
than the current scope and may consider developing test procedures for 
these compressors as part of a future rulemaking process.
4. Lubricant-Free Compressors
    As stated in section III.A of this document, the current test 
procedure for compressors applies to lubricated compressors (and 
therefore does not apply to lubricant-free compressors). 10 CFR 
431.344. In the February 2023 NOPR, DOE proposed to not expand the 
scope of the test procedure to include lubricant-free compressors. 88 
FR 9199, 9203-9204. DOE stated that it may evaluate the justification 
for developing test procedures for lubricant-free compressors as part 
of a future rulemaking process. DOE also asked for comment regarding 
its proposal to not include lubricant-free compressors within the scope 
of test procedure applicability.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all responded in 
agreement with DOE's proposal to not include lubricant-free compressors 
within the scope of test procedure applicability. (CAGI, No. 21 at p. 
2; Kaeser Compressors, No. 24 at p. 4; Ingersoll Rand, No. 25 at p. 2; 
Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    Kaeser Compressors encouraged DOE to evaluate recently added/
verified test standards for oil-free compressors and blowers for 
potential incorporation in a future rulemaking. Kaeser Compressors also 
added that, since there are many different compressor and blower 
technologies in the oil-free category, they may require different ways 
to develop efficiency and test standards. (Kaeser Compressors, No. 24 
at p. 2)
    ASAP, ACEEE, & NRDC recommended DOE expand the scope of this test 
procedure to cover lubricant-free compressors, because including 
lubricant-free compressors would mitigate the risk of unregulated 
product substitutions, which was a concern in the January 2017 Final 
Rule. (ASAP, ACEEE, & NRDC, No. 28 at p. 3)
    DOE discussed lubricant-free compressors in both the January 2017 
Final Rule (82 FR 1052, 1063) and the January 2020 ECS Final Rule (85 
FR 1504, 1519-1520), concluding that justification did not exist at the 
time to support extending the scope of test procedures or energy 
conservation standards to apply to lubricant-free compressors. DOE has 
determined that the conclusion made in the 2017 and 2020 final rules 
still applies for lubricant-free compressors.
    ASAP, ACEEE, & NRDC recommended that DOE mitigate the risk of 
unregulated product substitutions by expanding the scope of the test 
procedure to cover lubricant-free compressors and other categories of 
compressors, such as centrifugal and scroll compressors, instead of 
excluding lubricant-free compressors. (ASAP, ACEEE, & NRDC, No. 28 at 
p. 3) Section III.A.2 of this final rule, however, discusses that DOE 
is continuing to exclude centrifugal compressors from the scope of the 
test procedure at this time. As a result, in order to ensure that there 
is not competition between unregulated centrifugal compressors and 
regulated lubricant-free positive displacement rotary compressors, DOE 
is also excluding lubricant-free rotary positive displacement 
compressors from the scope of the test procedure at this time.
    For the reasons discussed in the previous paragraphs, at this time, 
DOE is not expanding the scope of the test procedure to include 
lubricant-free compressors. DOE may evaluate the justification for 
developing test procedures for lubricant-free compressors as part of a 
future rulemaking process.
5. Brushed Motors
    As stated in section III.A, the current test procedure for 
compressors applies only to compressors with brushless motors. 10 CFR 
431.344. In the February 2023 NOPR, DOE proposed to not expand the 
scope of the test procedure to include compressors with brushed motors. 
88 FR 9199, 9204. DOE stated that it may evaluate the justification for 
developing test procedures for compressors with brushed motors as part 
of a future rulemaking process. DOE also asked for comment regarding 
its proposal to not include compressors with brushed motors within the 
scope of test procedure applicability.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all responded in 
agreement with DOE's proposal to exclude compressors with brushed 
motors from the scope of test procedure applicability. (CAGI, No. 21 at 
p. 2;

[[Page 5545]]

Kaeser Compressors, No. 24 at p. 4; Ingersoll Rand, No. 25 at p. 2; 
Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    ASAP, ACEEE, & NRDC encouraged DOE to include compressors with 
brushed motors in the test procedure scope. (ASAP, ACEEE, & NRDC, No. 
28 at p. 1) ASAP, ACEEE, & NRDC commented that they were concerned that 
manufacturers could consider replacing brushless motors with less 
efficient brushed motors to avoid compressor regulations. (ASAP, ACEEE, 
& NRDC, No. 28 at p. 3)
    DOE discussed compressors with brushed motors in both the January 
2017 Final Rule (82 FR 1052, 1060) and the January 2020 ECS Final Rule 
(85 FR 1504, 1515), concluding that the burden associated with 
establishing testing requirements for brushed motor compressors 
outweighed the associated benefits. This was because, although there 
were potential benefits to expanding scope to include these models, 
brushed motors are uncommon in compressors with significant operating 
hours, and most brushed motor compressors are not tested for 
efficiency. 82 FR 1052, 1060. In addition, DOE stated that brushed 
motors are uncommon in compressors with significant potential energy 
savings (i.e., high operating hours) due to higher maintenance costs, 
short operating lives, significant acoustic noise, and electrical 
arcing. Id. For these reasons, DOE concluded that brushed motors are 
not a viable substitution risk for compressors within the scope of the 
DOE compressor test procedure. Id.
    DOE has determined that the conclusions made in the January 2017 
Final Rule still apply for compressors with brushed motors. Due to this 
reasoning, at this time, DOE is not expanding the scope of the test 
procedure to include compressors with brushed motors. DOE may evaluate 
the inclusion of compressors with brushed motors as part of a future 
rulemaking.
6. Output Pressure Less Than 75 psig
    As stated in section III.A, the current test procedure for 
compressors applies only to compressors that have a full-load operating 
pressure greater than or equal to 75 psig and less than or equal to 200 
psig. 10 CFR 431.344. In the February 2023 NOPR, DOE proposed to not 
include equipment for compressed air applications for pressures under 
75 psig within the scope of test procedure applicability. 88 FR 9199, 
9204. DOE stated that it may evaluate the justification for developing 
test procedures for compressors with output pressure of less than 75 
psig as part of a future rulemaking process. Id. DOE also asked for 
comment regarding its proposal to not include equipment for compressed 
air applications for pressures under 75 psig within the scope of test 
procedure applicability. Id.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all commented in 
agreement with DOE's proposal to not include compressors with output 
pressure less than 75 psig. (CAGI, No. 21 at p. 2; Kaeser Compressors, 
No. 24 at p. 4; Ingersoll Rand, No. 25 at p. 2; Saylor-Beall, No. 22 at 
p. 1; Sullivan-Palatek, No. 23 at p. 1)
    Kaeser Compressors encouraged DOE to evaluate recently added/
verified test standards for oil-free compressors and blowers for 
potential incorporation in a future rulemaking, which would include 
pressure ranges of 50-160 psig. Kaeser Compressors added that 1-30 psig 
is also a large area of energy consumption, which includes wastewater 
treatment and other aeration and conveying applications that include 
24/7 operation. (Kaeser Compressors, No. 24 at p. 2)
    At this time, DOE is not expanding the scope of the test procedure 
to include compressors with output pressure of less than 75 psig. DOE 
discussed compressors with output pressure of less than 75 psig in both 
the January 2017 Final Rule (82 FR 1052, 1062-1063) and the January 
2020 ECS Final Rule (85 FR 1504,1519), concluding that justification 
did not exist at the time to support extending the scope of either test 
procedures or energy conservation standards to apply to compressors 
with output pressure of less than 75 psig. DOE has determined that the 
conclusion made in the January 2017 Final Rule and the January 2020 ECS 
Final Rule still applies for compressors with output pressure of less 
than 75 psig. DOE may evaluate the justification for developing test 
procedures for compressors with output pressure of less than 75 psig as 
part of a future rulemaking process.
7. Integrated Dryers
    In response to the February 2023 NOPR, Kaeser Compressors commented 
that, while integrated dryers inside a compressor package are not 
listed in the DOE procedure, it might be necessary to specifically 
exclude them from this test procedure. (Kaeser Compressors, No. 24 at 
p. 8)
    Section 2.2.4 of appendix A contains tables 1 and 2, which specify 
the compressor components and ancillary equipment that must be present 
and installed when testing an air compressor. These tables were 
discussed in the January 2017 Final Rule. 82 FR 1052, 1055-1057, 1080-
1082. Table 1 to appendix A contains the equipment that must be present 
and installed for all tests. If the compressor is distributed in 
commerce without an item from table 1 to appendix A, the manufacturer 
must provide an appropriate item to be installed for the test. If any 
of the equipment listed in table 2 to appendix A is distributed in 
commerce with units of the compressor basic model, it must be present 
and installed for all tests specified in appendix A. Additional 
ancillary equipment beyond the items listed in tables 1 and 2 to 
appendix A may be installed for the test, if distributed in commerce 
with the compressor, but this additional ancillary equipment is not 
required.
    Neither table 1 nor table 2 to appendix A specify an integrated 
dryer, or any type of dryer, as a piece of equipment that must be 
installed for testing. Table 1 to appendix A specifies a moisture 
separator and drain, but this is different from a dryer, in that a 
moisture separator removes liquid water from the air, whereas a dryer 
removes water vapor from the air. As a result, an integrated dryer is 
not required to be present and installed for the tests specified in the 
compressors test procedure. A manufacturer may install an integrated 
dryer for the tests if the integrated dryer is distributed in commerce 
with the compressor, but the integrated dryer is not required.
    Although Kaeser Compressors suggested that it might be necessary to 
specifically exclude integrated dryers from the test procedure, DOE is 
not doing that in this final rule. As discussed in the previous 
paragraphs, a manufacturer is not required to install an integrated 
dryer for testing, but the manufacturer may install an integrated dryer 
if they wish to represent the performance of their compressor with an 
integrated dryer installed. This flexibility is indicated by the text 
of section 2.2.4 of appendix A and tables 1 and 2 to appendix A, and no 
changes are required at this time to clarify this flexibility.

B. Updates to Industry Standards

1. ISO 1217:2009(E) as the Basis for This Test Procedure
    DOE's current test procedure incorporates by reference certain 
sections of ISO 1217:2009(E) as amended through Amendment 1:2016 for 
test methods and acceptance tests regarding volume rate of flow and 
power requirements of displacement

[[Page 5546]]

compressors, in addition to the operating and testing conditions that 
apply when a full performance test is specified. In the February 2023 
NOPR, DOE did not propose amendments to the existing reference to ISO 
1217:2009(E) as amended through Amendment 1:2016 as the basis for the 
compressors test procedure. 88 FR 9199, 9204-9205. DOE also asked for 
comment regarding its initial determination to continue to use ISO 
1217:2009(E) as amended through Amendment 1:2016 as the basis for the 
compressors test procedure.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all commented in 
agreement with DOE's proposal to continue to use ISO 1217:2009(E) as 
amended through Amendment 1:2016 as the basis for the compressors test 
procedure. (CAGI, No. 21 at p. 3; Kaeser Compressors, No. 24 at p. 4; 
Ingersoll Rand, No. 25 at p. 2; Saylor-Beall, No. 22 at p. 1; Sullivan-
Palatek, No. 23 at p. 1)
    DOE agrees with the comments received and is continuing to 
incorporate by reference certain sections of ISO 1217:2009(E) as 
amended through Amendment 1:2016 in the compressors test procedure at 
10 CFR 431.343. As discussed in section III.E.1, DOE is revising 10 CFR 
431.343 to add section B.4.5 of Annex B of ISO 1217:2009(E) to the list 
of sections that DOE is incorporating by reference in the compressors 
test procedure. See section III.E.1 for a full discussion of this 
revision.
2. Ambient Temperature Range Requirement
    DOE adopted the ambient temperature range for testing of 68 to 90 
[deg]F in the January 2017 Final Rule partially in response to concern 
that creating a climate-controlled space for testing compressors could 
be a significant burden on small businesses. DOE stated that this 
temperature range provides representative measurements without unduly 
burdening manufacturers. 82 FR 1052, 1079-1080. In the February 2023 
NOPR, DOE proposed to maintain the current ambient temperature range 
requirement of 68 to 90 [deg]F for testing air compressors. 88 FR 9199, 
9205. DOE also asked for comment regarding its proposal to maintain the 
current ambient temperature range requirement.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all commented in 
agreement with DOE's proposal to maintain the current ambient 
temperature range requirement of 68 to 90 [deg]F for testing air 
compressors. (CAGI, No. 21 at p. 3; Kaeser Compressors, No. 24 at p. 5; 
Ingersoll Rand, No. 25 at p. 2; Saylor-Beall, No. 22 at p. 1; Sullivan-
Palatek, No. 23 at p. 1) They added that narrowing the range or 
specifying specific requirements would add burden to the industry 
without providing any advantages to consumers. (Id.)
    For the reasons discussed in the February 2023 NOPR and the 
previous paragraphs, DOE is not amending the current ambient 
temperature range requirement of 68 to 90 [deg]F for testing air 
compressors in this final rule.

C. Definitions

1. Multi-Element Air Compressors
    Air compressors may include multiple compression elements to 
increase compression efficiency or to generate a greater pressure 
increase than would be possible with a single compression element. The 
current definition of ``air compressor'' specifies inclusion of a 
compression element but does not exclude air compressors that include 
more than one compression element. DOE discussed the current definition 
of ``air compressor'' as applying to multi-element air compressors in 
both the January 2017 Final Rule (82 FR 1052, 1068) and the January 
2020 ECS Final Rule, in which multi-staging was identified as a 
technology option for improving the energy efficiency of compressors. 
85 FR 1504, 1537.
    In the February 2023 NOPR, DOE tentatively determined that revising 
the definition of ``air compressor'' to explicitly include air 
compressors with more than one compression element would reduce the 
probability that the definition is misinterpreted to exclude air 
compressors with more than one compression element. 88 FR 9199, 9205-
9206. DOE proposed to amend the definition of ``air compressor'' such 
that ``compression element (bare compressor)'' is replaced by ``one or 
more compression elements (bare compressors).'' Id. Additionally, DOE 
proposed to change ``compressor element'' to ``compression elements'' 
to correct a typographical error. Id. DOE also issued a request for 
comment in the February 2023 NOPR regarding its proposed amendment of 
the definition of ``air compressor.'' 88 FR 9199, 9206.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, Sullivan-Palatek, and CA IOUs all 
expressed support for DOE's proposed amendment to the definition of 
``air compressor.'' (CAGI, No. 21 at p. 2; Kaeser Compressors, No. 24 
at p. 4; Ingersoll Rand, No. 25 at p. 2; Saylor-Beall, No. 22 at p. 1; 
Sullivan-Palatek, No. 23 at p. 1; CA IOUs, No. 27 at p. 1)
    The current formulation of the definition of ``air compressor'' 
does not exclude air compressors with more than one compression 
element; nonetheless, stating expressly that multi-element compressors 
meet the definition of ``air compressor'' limits the potential for 
misinterpretation.
    For the reasons discussed in the February 2023 NOPR and the 
preceding paragraphs, DOE is amending the definition of ``air 
compressor'' to be ``a compressor designed to compress air that has an 
inlet open to the atmosphere or other source of air, and is made up of 
one or more compression elements (bare compressors), driver(s), 
mechanical equipment to drive the compression elements, and any 
ancillary equipment.''

D. Efficiency Metrics

1. Load Point for Fixed-Speed Compressors
    The current efficiency metric for fixed-speed compressors, full-
load package isentropic efficiency, uses a single load point at 100 
percent of full-load actual volume flow rate. In the February 2023 
NOPR, DOE proposed to maintain the requirement to measure the 
performance of fixed-speed compressors at full load, or more 
specifically, full-load actual volume flow rate at full-load operating 
pressure, as described in paragraph 3.3.1 of appendix A. 88 FR 9199, 
9209. DOE also asked for comment on whether the test procedure reflects 
actual operating costs for compressors based on their realistic average 
use cycles. Id.
    In response to the February 2023 NOPR, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all expressed 
support for the provision that the test procedure can be considered 
reflective of realistic average use cycles. They commented that, in 
practical terms, no one compressor installation will have identical or 
predictable use cycles, and that the current regulatory provision to 
certify fixed-speed machines based on their performance at 100 percent 
flow rate and for variable-speed machines based on a weighted average 
for flow conditions provides a realistic, representative framework for 
testing, certifying, and presenting meaningful and consistent data to 
customers. (CAGI, No. 21 at p. 5; Kaeser Compressors, No. 24 at p. 8; 
Ingersoll Rand, No. 25 at p. 4; Saylor-Beall, No. 22 at p. 1; Sullivan-
Palatek, No. 23 at p. 1)

[[Page 5547]]

    For the reasons discussed in the February 2023 NOPR and preceding 
paragraphs, DOE is not proposing to alter the current metric for fixed-
speed compressors in this test procedure final rule.
2. Load Points for Variable-Speed Compressors
    The part-load package isentropic efficiency metric for variable-
speed air compressors uses three load points: 40, 70, and 100 percent 
of full-load actual volume flow rate. In the February 2023 NOPR, DOE 
proposed to continue using those load points. 88 FR 9199, 9208-9209. 
DOE requested comment on its proposal to maintain the number of load 
points for variable-speed air compressors and to not include points 
with greater than 100 percent of full-load actual volume flow rate. Id.
    In response to the request for comment in the February 2023 NOPR, 
CAGI, Kaeser Compressors, Ingersoll Rand, Saylor-Beall, and Sullivan-
Palatek all expressed support for the DOE proposal to maintain the 
number of test points and to not include points with greater than 100-
percent load.
    For the reasons discussed in the February 2023 NOPR and the 
previous paragraphs, in this final rule, DOE is maintaining the load 
points for the part-load package isentropic efficiency metric for 
variable-speed air compressors at 100 percent, 70 percent, and 40 
percent of full-load actual volume flow rate.
3. Inclusion of Unloaded Operation for Fixed-Speed Compressors
    The isentropic efficiency metric for fixed-speed compressors 
currently includes performance at full-load operation only. No measure 
of performance is included from unloaded operation. In the February 
2023 NOPR, DOE proposed to maintain this exclusion of unloaded 
operation from the isentropic efficiency metric. 88 FR 9199, 9208.
    ASAP, ACEEE, & NRDC encouraged DOE to explore how unloaded power 
measurements could be incorporated into the test procedure. ASAP, 
ACEEE, & NRDC stated that fixed-speed air compressors are tested and 
evaluated only at full load. However, they elaborated that fixed-speed 
compressors often include controls such as ``load/unload'' or ``start/
stop'' and commented that testing and evaluating fixed-speed compressor 
efficiency at both fully loaded and fully unloaded (i.e., zero flow) 
conditions would be more representative of typical usage. ASAP, ACEEE, 
& NRDC further stated that the CAGI Performance Verification Program 
already specifies testing at a fully unloaded test point, and that 
capturing differences in unloaded power usage will become increasingly 
important as compressor efficiencies improve. (ASAP, ACEEE, & NRDC, No. 
28 at p. 3)
    NEEA & NPCC recommended that DOE include a no-load power 
measurement in the test procedure for fixed-speed compressors that use 
start/stop and load/unload control strategies. NEEA & NPCC stated that 
unlike variable-airflow controls, fixed-speed air compressors that use 
start/stop and load/unload control strategies operate at either fully 
loaded or fully unloaded states, and testing units that have start/stop 
or load/unload control strategies at fully loaded and fully unloaded 
states would be more representative of typical usage. NEEA & NPCC 
commented that the January 2020 ECS Final Rule indicates that a 
significant portion of annual energy consumption is spent in a no-load 
or fully unloaded state for fixed-speed compressors with unload 
strategies. NEEA & NPCC further stated that, because the metric does 
not currently account for a no-load power, DOE can't consider 
technologies that reduce no-load power consumption in its standard 
analysis; manufacturers that develop products that use less energy in 
no-load are not given credit in their regulated ratings; and the DOE 
test procedure assumption for non-operating hours is zero, which is not 
in agreement with the analysis performed in the January 2020 ECS Final 
Rule and does not align with the typical usage of compressors. NEEA & 
NPCC also stated that standby mode and off mode energy consumption 
measurements are required for all consumer products' test procedures, 
and that including a no-load power measurement for industrial equipment 
that consumes power in a no-load state, such as start/stop and load/
unload compressors, ensures consistency in test procedure requirements 
across industrial and consumer products. (NEEA & NPCC, No. 26 at pp. 5-
6)
    NEEA & NPCC disagreed with DOE's statement in the February 2023 
NOPR that testing at a no-load state is not an essential output of the 
test procedure and, therefore, would cause unneeded incremental burden 
on testing and reporting requirements. NEEA & NPCC stated that DOE 
requiring testing at a no-load state is the necessary step for no-load 
power measurement to be an essential output of the test procedure. NEEA 
& NPCC also stated that the incremental burden of testing a unit at a 
no-load state is minimal, as units under test are already set up for 
testing at specified load points and the CAGI data sheets already 
specify tolerances for testing at a fully unloaded test point. (NEEA & 
NPCC, No. 26 at p. 6)
    DOE agrees that information describing unloaded states of operation 
could be useful to the end user. This subject was discussed in the 
January 2017 Final Rule. 82 FR 1052, 1068-1070. This included mention 
of possible methods to include loaded and unloaded points in a 
representative manner, including, potentially, the energy required 
during the transient periods between loaded and unloaded operation. Id. 
At the time, it was noted that there were no methods that had been 
developed and accepted by industry consensus, although Atlas Copco did 
provide an example of a cycle energy requirement approach to consider 
the energy during loaded operation, unloaded operation, and the 
transient periods between loaded and unloaded operation. Id. At the 
time, DOE did not include unloaded performance in its isentropic 
efficiency metric because there was no accepted industry test method. 
Id. DOE indicated at the time that DOE may consider incorporating such 
a method in future rulemakings if the metric gains acceptance in the 
industry and the test method can be formalized and validated beyond a 
case study. 82 FR 1052, 1069. DOE also stated that manufacturers may 
measure and advertise unloaded power, but it would not require 
measurement of unloaded performance as part of the test procedure. 82 
FR 1052, 1070.
    At the current time, DOE is not aware that an industry standard 
test method has been developed to provide a representative measure of 
performance across loaded and unloaded operation. In a comment in 
response to the February 2023 NOPR, Kaeser Compressors indicated that 
DOE could consider new industrial standards for a future rulemaking, 
including ISO 4376, Cycle energy requirement.\6\ This standard is 
described on the ISO website as measuring the additional energy 
required for a single cycle caused by transient conditions, which 
sounds similar to the method from Atlas Copco that was discussed in the 
January 2017 Final Rule. The standard is currently listed as ``under 
development'' on the ISO website, and DOE is not aware of any 
compressors that are currently rated using this standard. As a result, 
it appears that this standard is not currently being used widely by 
industry. DOE is also not aware of any other industry consensus method 
to

[[Page 5548]]

combine loaded and unloaded performance.
---------------------------------------------------------------------------

    \6\ Available at iso.org/standard/85352.html.
---------------------------------------------------------------------------

    The concerns that existed in the January 2017 Final Rule regarding 
the lack of an accepted industry test method to combine loaded and 
unloaded performance still exist. As a result, DOE is not including any 
measure of unloaded performance in the metrics of the compressors test 
procedure at this time, although manufacturers may measure and 
advertise unloaded power. DOE may consider including unloaded 
performance in the metrics of the compressors test procedures as part 
of a future rulemaking process.
4. Part-Load Performance of Fixed-Speed Compressors With Variable-
Airflow Controls
    The isentropic efficiency metric for fixed-speed compressors 
includes performance at full-load operation only. No measure of 
performance is included from part-load operation. In the February 2023 
NOPR, DOE proposed to maintain this exclusion of part-load operation 
from the isentropic efficiency metric for fixed-speed compressors. 88 
FR 9199, 9208.
    ASAP, ACEEE, & NRDC encouraged DOE to include voluntary testing and 
reporting of part-load performance of fixed-speed compressors with 
variable-airflow controls. ASAP, ACEEE, & NRDC stated that fixed-speed 
compressors sold with variable-airflow controls, such as ``variable 
displacement'' or ``inlet modulation,'' can provide similar utility as 
variable-speed compressors. Thus, ASAP, ACEEE, & NRDC stated that DOE 
should provide specific voluntary provisions to test and rate 
compressors with variable-airflow controls (e.g., using the variable-
speed compressor test points at 40, 70, and 100 percent of full load). 
ASAP, ACEEE, & NRDC further stated that part-load testing of fixed-
speed compressors with airflow controls would facilitate comparison of 
part-load efficiency among variable-airflow compressors as well as 
between variable-airflow and variable-speed compressors. Finally, ASAP, 
ACEEE, & NRDC indicated that these provisions would also ensure that 
any manufacturer representations of variable-airflow compressor part-
load performance are consistent across the industry. (ASAP, ACEEE, & 
NRDC, No. 28 at pp. 3-4)
    NEEA & NPCC recommended DOE coordinate with CAGI in rating fixed-
speed rotary compressors with variable-airflow controls at variable 
load points to align with variable-speed compressors. NEEA & NPCC 
stated that many fixed-speed rotary compressors have variable-airflow 
controls and non-flat load profiles. Fixed-speed compressors that use 
variable-airflow controls, such as inlet valve modulation and variable 
displacement, provide the same function as variable-speed compressors; 
however, these compressors are tested only at full-load operation 
currently. Testing fixed-speed rotary compressors with variable-airflow 
controls at variable load points would be more representative of 
typical usage and produce a more representative isentropic efficiency. 
Furthermore, NEEA & NPCC stated that by not testing compressors with 
variable-airflow controls at part-load set points, consumers cannot 
compare and select the most efficient air compressors for part-load 
operations. (NEEA & NPCC, No. 26 at p. 4)
    NEEA & NPCC disagreed with DOE's reasoning in the February 2023 
NOPR that because fixed-speed rotary compressors in the CAGI data 
sheets are rated at only full-load isentropic efficiency, establishing 
part-load isentropic efficiencies for compressors with variable-airflow 
controls in the test procedure is not warranted at this time. NEEA & 
NPCC stated that DOE should consider improvements to the testing of 
variable-airflow compressors for several reasons. First, NEEA & NPCC 
stated that DOE is not limited to CAGI's performance verification 
program or the information on CAGI data sheets in their test procedure, 
and that DOE should fully consider the burden and value of changes to 
the testing of fixed-speed variable-airflow compressors. Second, NEEA & 
NPCC commented that the January 2020 ECS Final Rule indicated that 
about 37 percent of fixed-speed industrial air compressors use inlet 
valve modulation or variable displacement with high, low, or even load 
profiles, indicating that a significant portion of fixed-speed air 
compressors are tested in conditions at which they rarely or never 
operate. Finally, NEEA & NPCC commented that there may be a significant 
savings opportunity for fixed-speed rotary compressors with variable-
airflow controls, and that DOE should investigate the savings 
opportunity by testing these compressors the same as variable-speed 
compressors. NEEA & NPCC stated that if significant savings potential 
is noted, DOE should update testing to better reflect the energy 
consumption and potential for savings in this equipment. In addition, 
NEEA & NPCC stated that DOE could also coordinate with CAGI on how to 
include these reporting requirements in their data sheets so that both 
continue to align, should DOE make changes. (NEEA & NPCC, No. 26 at p. 
6)
    DOE agrees that a part-load package isentropic efficiency metric 
for fixed-speed variable-airflow compressors could acceptably represent 
the typical energy use of fixed-speed compressors with variable-airflow 
controls. This subject was discussed in the January 2017 Final Rule. 82 
FR 1052, 1072-1073. At the time, it was noted that CAGI was doing 
preliminary work on developing a method for one of these control 
methods (variable displacement), but that there was not yet an industry 
consensus method for measuring the part-load performance of variable-
airflow fixed-speed compressors. Id. at 82 FR 1073. The lack of an 
accepted test method was one of the reasons that DOE did not include a 
part-load package isentropic efficiency metric for fixed-speed 
variable-airflow compressors in the test procedure. The other reasons 
included the lack of historical part-load performance data for these 
compressors and the approach taken by CAGI and the EU Lot 31 draft 
standard. Id. DOE also acknowledged in the January 2017 Final Rule that 
part-load performance information for these varieties of compressors 
can provide valuable information for the end user, and that 
manufacturers of fixed-speed compressors may continue making graphical 
or numerical representations of package isentropic efficiency and 
package specific power as functions of flow rate or rotational speed. 
Id.
    At the current time, DOE is not aware of an industry consensus 
method for measuring part-load package isentropic efficiency for fixed-
speed variable-airflow compressors, nor is DOE aware of this metric 
being used widely for this category of compressors. As a result, the 
concerns that existed in the January 2017 Final Rule regarding the lack 
of an accepted industry test method still exist. Therefore, DOE is not 
including any measure of part-load package isentropic efficiency for 
fixed-speed variable-airflow compressors in the compressors test 
procedure at this time. DOE may consider part-load package isentropic 
efficiency for fixed-speed variable-airflow compressors as part of a 
future rulemaking process.

E. Test Method

1. K6 Correction Factor
    ISO 1217:2009(E) contains several correction factors that correct 
for variables of the environment, process gas, and compressor 
operation. The K6 correction factor in ISO 1217:2009(E) is 
labeled in section 4.1 of ISO 1217:2009(E) as the correction factor for

[[Page 5549]]

the isentropic exponent. The DOE test procedure uses only a subset of 
the correction factors in ISO 1217:2009(E), and it does not use the 
K6 correction factor. The DOE test procedure specifies in 
sections 3.3.2.2, 3.4.3.2, 3.4.4.2, and 3.5 of appendix A to multiply 
measured power by the K5 correction factor, which is labeled 
in section 4.1 of ISO 1217:2009(E) as the correction factor for the 
inlet pressure, polytropic exponent, and pressure ratio.
    In response to the May 2022 RFI, DOE received comments about 
potentially needing to use the K6 correction factor in 
certain situations. CAGI, supported by Kaeser Compressors, commented 
that if testing is conducted at sites significantly above sea level, 
use of the K6 correction factor may be necessary to obtain 
accurate representative results. (CAGI, No. 11 at p. 2; Kaeser 
Compressors, No. 17 at p. 1)
    In the February 2023 NOPR, DOE explained that DOE had deliberately 
omitted the K6 correction factor during the January 2017 
Final Rule. 82 FR 1052, 1084; 88 FR 9199, 9206. As listed in the 
footnotes of the January 2017 Final Rule, the isentropic exponent of 
air has some limited variability with atmospheric conditions, and DOE 
adopted a fixed value of 1.400 to align with the EU Lot 31 draft 
standard's metric calculations. Id. As such, DOE did not propose to 
amend the current fixed value of 1.400 for the isentropic exponent in 
the February 2023 NOPR. 88 FR 9199, 9206. DOE also asked for comment 
regarding its initial determination to continue to use a fixed value of 
1.400 for the isentropic exponent, as opposed to incorporating a 
K6 correction factor. Id.
    In response to the request for comment, CAGI, supported by Kaeser 
Compressors, Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek, 
commented in support of DOE's initial determination to continue to use 
a fixed value of 1.400 for the isentropic exponent of air. However, 
they added that to ensure results derived from testing at elevation are 
accurate, the K6 correction factor is necessary to 
incorporate both isentropic exponent and pressure ratio. They indicated 
that is necessary to correct the measured power with both the 
K5 and K6 correction factors in order to correct 
for inlet pressure and pressure ratio. The DOE test procedure directs 
that performance be normalized to a reference ambient inlet pressure of 
100 kPa, approximately corresponding to an altitude of 364 ft above sea 
level. CAGI presented a table illustrating that calculated results are 
incorrect at elevations greater than and less than 364 ft if 
K6 is not used. (CAGI, No. 21 at pp. 3-5; Kaeser 
Compressors, No. 24 at p. 6; Ingersoll Rand, No. 25 at p. 3; Saylor-
Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1) The commenters 
also indicated that correcting the DOE test procedure to include 
K6 will reduce burdens and potential burdens for the 
industry, because currently the DOE test method and its correction 
deviates from the national consensus standard. They also stated that 
correcting the procedure will not result in a need to retest and 
recertify but will ensure that any verification/certification performed 
at any elevation other than 364 ft or during low- or high-pressure 
weather events will be correct. (CAGI, No. 21 at pp. 4-5; Kaeser 
Compressors, No. 24 at pp. 8-9; Ingersoll Rand, No. 25 at pp. 4-5; 
Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    After reviewing CAGI's comments and the content of ISO 
1217:2009(E), DOE now understands that K6 is required to 
calculate package isentropic efficiency and specific power accurately 
in the DOE test procedure. Although K5 is labeled as 
``correction factor for inlet pressure, polytropic exponent and 
pressure ratio'' and K6 is labeled as ``correction factor 
for isentropic exponent'' in section 4.1 of ISO 1217:2009(E), which 
appears to be inaccurate. K5, as determined in section 
C.4.3.2 of Annex C to ISO 1217:2009(E), appears to correct only for 
inlet pressure, because it is a ratio of inlet pressures. 
K6, as determined in section B.4.5 of Annex B to ISO 
1217:2009(E), appears to correct for both the isentropic exponent and 
pressure ratio, because it contains ratios of isentropic exponents and 
pressure ratios. In the case of the DOE test procedure, for which a 
fixed value of 1.400 is used for the isentropic exponent, K6 
will correct for only pressure ratio. For the packaged compressors 
covered by the DOE test procedure, both inlet pressure and pressure 
ratio change with elevation and weather conditions. By including the 
K5 correction factor but excluding the K6 
correction factor, the DOE test procedure currently corrects for 
variations in inlet pressure but does not correct for variations in 
pressure ratio. By including K6 as well, the DOE test 
procedure will correct for variations in both inlet pressure and 
pressure ratio, thereby resulting in more accurate measurements of 
isentropic efficiency and specific power.
    To incorporate the K6 correction factor, DOE is making 
the following changes in the DOE test procedure. First, DOE is 
incorporating by reference section B.4.5 of ISO 1217:2009(E) into 
subpart T of 10 CFR part 431, which includes equations to calculate the 
K6 correction factor: equation B.9 for single-stage 
displacement compressors with or without cooling and multi-stage 
compressors without intercooling, and equation B.10 for multi-stage 
displacement compressors with intercoolers. Second, DOE is revising 
sections 3.3.2.2, 3.4.3.2, 3.4.4.2, and 3.5 of appendix A to multiply 
measured power by both K5 and K6, instead of only 
multiplying measured power by K5.
    As indicated by commenters, these changes will make the results of 
the DOE test procedure more accurate, reduce burden by making the DOE 
test procedure consistent with the industry test method, and not 
require any retesting or recertifying.
2. Correction of Pressure Ratio at Full-Load Operating Pressure Formula
    Section 3.6 of appendix A specifies a formula for pressure ratio at 
full-load operating pressure, which is used to classify whether a 
machine or apparatus qualifies as a compressor, as the definition of 
``compressor'' stated in 10 CFR 431.342 states that the machine or 
apparatus must have a pressure ratio at full-load operating pressure 
greater than 1.3. Pressure ratio at full-load operating pressure does 
not factor directly into the measured values of compressor performance.
    In response to the May 2022 RFI, DOE received comments noting that 
there is an apparent error in the formula for pressure ratio. In the 
February 2023 NOPR, DOE concurred with the commenters that the current 
formula contains an error, as it both does not match the discussion in 
the preamble of the January 2017 Final Rule and does not contain terms 
related to the calculation of pressure ratio at full-load operating 
pressure. 88 FR 9199, 9207.
    The current formula for pressure ratio at full-load operating 
pressure inadvertently duplicates a formula used in a calculation 
related to determining a represented value of performance for a 
compressor basic model from a tested sample of units. Specifically, the 
current formula of pressure ratio at full-load operating pressure 
exactly matches the formula for the lower 95-percent confidence limit 
(``LCL'') of the true test mean divided by 0.95. In the February 2023 
NOPR, DOE proposed to change the formula for pressure ratio at full-
load operating pressure in section 3.6 of appendix A to rectify this 
error and reflect the proper pressure ratio at full-load operating 
pressure equation that will be utilized in the test procedure. The 
numerator of this proposed formula for pressure ratio incorporated 
full-load

[[Page 5550]]

operating pressure, determined in section 4.3.4 of appendix A (Pa 
gauge), while the denominator was standard atmospheric pressure, 100 
kPa. 88 FR 9199, 9207.
    DOE requested comment in the February 2023 NOPR regarding its 
proposal to correct the equation for pressure ratio at full-load 
operating pressure. In response, CAGI, supported by Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek, commented in 
support of DOE's proposal to correct the equation for pressure ratio at 
full-load operating pressure to amend a previous typographical error. 
In addition, the commenters noted that pressure ratio must always be 
calculated in terms of absolute pressure and recommended the addition 
of 100 kPa to the numerator of the equation to achieve this. (CAGI, No. 
21 at p. 4; Kaeser Compressors, No. 24 at p. 7; Ingersoll Rand, No. 25 
at p. 4; Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 
1)
    DOE evaluated the stakeholders' recommendation to express pressure 
ratio in terms of absolute pressure and agrees with the proposed 
solution. ``Absolute pressure'' is defined as pressure relative to a 
perfect vacuum. In the correction proposed in the February 2023 NOPR, 
the equation for pressure ratio expresses pressure in terms of gauge 
pressure in the numerator and absolute pressure in the denominator. 88 
FR 9199, 9207. ``Gauge pressure'' is defined as the pressure above 
atmospheric pressure and has a different reference pressure compared to 
absolute pressure. For the calculated pressure ratio to be accurate, 
both the numerator and denominator must be expressed in terms of 
absolute pressure.
    As a result, in this test procedure final rule, DOE is amending the 
formula for pressure ratio at full-load operating pressure in section 
3.6 of appendix A to rectify the typographical error and to adjust the 
proposed equation so that pressure ratio is calculated in terms of 
absolute pressure by adding atmospheric pressure of 100 kPa to the 
numerator. The amended calculation for pressure ratio at full-load 
operating pressure is shown below in equation 1:
[GRAPHIC] [TIFF OMITTED] TR17JA25.092

Where:

PR = pressure ratio at full-load operating pressure;
P1 = 100 kPa; and
PFL = full-load operating pressure, determined in section 
4.3.4 of appendix A to subpart T of part 431 (Pa gauge).

    This change has no effect on the scope of compressors subject to 
the test procedure and does not increase the associated testing burden 
on manufacturers.
3. Tolerances for Measured Energy Efficiency Values
    DOE adopted the tolerances specified in table 1 of ISO 1217:2009(E) 
in the January 2017 Final Rule in order to align with ISO 1217:2009(E), 
as amended, to reduce the burden and cost to manufacturers. DOE stated 
that most manufacturers currently use ISO 1217:2009(E), and with the 
modifications adopted in the January 2017 Final Rule, the test methods 
established for compressors are intended to produce results equivalent 
to those produced historically under ISO 1217:2009(E). 82 FR 1052, 
1076. In the February 2023 NOPR, DOE proposed to continue to use the 
tolerances for measured energy efficiency values specified in ISO 
1217:2009(E) and asked for comment regarding this proposal. 88 FR 9199, 
9205.
    In response to the request for comment, CAGI, Kaeser Compressors, 
Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek all commented in 
support of DOE's proposal to continue to use the tolerances for 
measured energy efficiency values specified in ISO 1217:2009(E). (CAGI, 
No. 21 at p. 3; Kaeser Compressors, No. 24 at p. 5; Ingersoll Rand, No. 
25 at p. 2; Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at 
p. 1) CAGI stated that uncertainty of measurement and variation in 
performance as a result of variation in manufacturing needs to be 
reflected in data presented to consumers, and that tolerances defined 
in Annex C of ISO 1217:2019 relate only to the verification of the 
measured parameters by a practical test. Id.
    For the reasons discussed in the previous paragraphs, DOE is not 
amending the tolerances for measured energy efficiency values specified 
in ISO 1217:2009(E).

F. Reporting

    Manufacturers, including importers, must use product-specific 
certification templates to certify compliance to DOE. For compressors, 
the certification template reflects the general certification 
requirements specified at 10 CFR 429.12 and the product-specific 
requirements specified at 10 CFR 429.63. DOE is not amending the 
product-specific certification requirements for these products at this 
time.

G. Test Procedure Costs and Harmonization

    EPCA requires that test procedures established by DOE not be unduly 
burdensome to conduct. (42 U.S.C. 6293(b)(3)) The following sections 
discuss DOE's evaluation of estimated costs associated with the 
amendments included in this final rule.
    In this final rule, DOE is amending the test procedure for 
compressors by: (1) correcting the formula for calculating isentropic 
efficiency and specific energy consumption of the packaged compressor 
to the specified pressure ratio by incorporating a K6 
correction factor, (2) updating the formula for pressure ratio at full-
load operating pressure currently presented in appendix A to rectify a 
previous error, and (3) modifying the current definition of ``air 
compressor'' to clarify that compressors with more than one compression 
element are still within the scope of this test procedure, and to 
revise the typographical error of ``compressor element'' to 
``compression element.''
1. Amendment To Incorporate K6 Correction Factor
    In the February 2023 NOPR, DOE issued a request for comment on the 
benefits and burdens of the proposed updates to the test procedure for 
compressors. 88 FR 9199, 9210. In response to DOE's request for 
comment, regarding DOE's amendment to include a K6 
correction factor, DOE received comments from CAGI, supported by Kaeser 
Compressors, Ingersoll Rand, Saylor-Beall, and Sullivan-Palatek, 
stating that this correction will reduce potential burdens for the 
industry. These commenters commented that,

[[Page 5551]]

currently, the DOE test method and its correction deviate from the 
national consensus standard. These commenters believe this deviation 
was not intentional, as it provides no benefit and reduces test 
accuracy. These commenters further stated that the error and deviation 
are more significant the farther the elevation is from 364 ft. These 
commenters also stated that error can occur during atmospheric weather 
events leading to extreme low or high pressure, and that testing that 
is not performed at the exact rated full-load operating pressure is 
incorrectly converted to efficiency and specific power in the current 
DOE test procedure. CAGI elaborated that 100 kPa represents the mean 
ambient pressure at 111 m (364 ft), and that if lab elevation differs 
significantly from this level, measurements deriving efficiency will 
deviate when using the DOE test method. CAGI stated that, using the 
industry standard correction, the efficiency as measured (with no 
corrections) is the same exact value as applying K5 and 
K6 factors to correct specific power consumption and 
deriving isentropic efficiency at the conclusion (as presented in Annex 
C and Annex H of ISO 1217:2009). CAGI concluded that correcting the 
test procedure using their recommendations will not result in a need to 
retest and recertify, but will ensure that any verification/
certification performed at any elevation other than 364 ft or during 
low- or high-pressure events will be correct. (CAGI, No. 21 at pp. 5-6; 
Kaeser Compressors, No. 24 at pp. 8-9; Ingersoll Rand, No. 25 at pp. 4-
5; Saylor-Beall, No. 22 at p. 1; Sullivan-Palatek, No. 23 at p. 1)
    DOE agrees with the stakeholder comments that the incorporation of 
the K6 correction factor will not add any test burden or 
associated costs and will only increase the accuracy of efficiency 
representations in this test procedure. DOE has also determined that 
this amendment will not require retesting or recertification solely as 
a result of DOE's adoption of the amendment to the test procedures, 
since the amendment aligns the test procedure with existing industry 
practice. Current industry practice is to use the K6 
correction factor to correct for error introduced by non-standard 
ambient pressures when testing at elevations above or below 364 ft. As 
such, although the newly incorporated correction factor would alter the 
final efficiency output of the DOE test procedure for compressors 
tested at non-standard ambient pressures as compared to the incorrect 
calculation in the current test procedure, this correction will not 
result in a need for manufacturers to retest or to update the 
isentropic efficiency ratings of their compressors because the industry 
already uses the appropriate correction factor consistent with the 
existing industry test procedure. This amendment serves to harmonize 
the DOE test procedure with the existing industry practice for testing 
compressor efficiency.
    DOE does not anticipate any added test burden or associated costs 
from the amendment incorporating the K6 correction factor, 
as: (1) the test method follows accepted industry practice, and (2) 
representations of compressor efficiency would not need to be updated, 
since the amendment DOE is adopting in this final rule will align DOE's 
test procedure with current industry testing practice, making it so 
manufacturers do not need to retest their models. As any 
representations are voluntary prior to the compliance date of any 
energy conservation standards for compressors, there is no direct 
burden associated with any of the testing requirements adopted in this 
final rule.
2. Amendment To Update Formula for Pressure Ratio at Full-Load 
Operating Pressure
    The amendment regarding updating the formula for pressure ratio at 
full-load operating pressure will not impact the representations of 
compressor energy efficiency/energy use. The definition of a compressor 
is ``a machine or apparatus that converts different types of energy 
into the potential energy of gas pressure for displacement and 
compression of gaseous media to any higher-pressure values above 
atmospheric pressure and has a pressure ratio at full-load operating 
pressure greater than 1.3,'' as stated in 10 CFR 431.342. In the test 
procedure for compressors, the calculation of pressure ratio at full-
load operating pressure is only used to determine if a compressor meets 
the statutory definition of ``compressor'' by ensuring that the 
pressure ratio at full-load operating pressure is greater than 1.3. As 
such, this amendment does not impact representations of energy 
efficiency/energy use, and DOE does not anticipate any added test 
burden or associated costs for manufacturers stemming from this 
correction to the compressors test procedure.
3. Amendment To Update Definition of ``Air Compressor''
    DOE does not anticipate any added test burden or associated costs 
from the amendment updating the definition of ``air compressor.'' This 
amendment serves to clarify that compressors with more than one 
compression element are still within the scope of this test procedure, 
and to revise the typographical error of ``compressor element'' to 
``compression elements.'' As such, DOE does not anticipate any added 
test burden or associated costs for compressor manufacturers due to 
this amendment.
4. 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 of 10 CFR 
part 430 subpart C. In cases where the industry standard does not meet 
EPCA statutory criteria for test procedures, DOE will make 
modifications through the rulemaking process to these standards as the 
DOE test procedure.
    The test procedure for compressors at appendix A is based on, and 
incorporates by reference, much of ISO 1217:2009(E), ``Displacement 
compressors--Acceptance tests,'' as amended through Amendment 1:2016. 
In this final rule, DOE will incorporate by reference section B.4.5 of 
Annex B of ISO 1217:2009(E) via amendment. The industry standards DOE 
has incorporated by reference for the test procedure for compressors 
are located in 10 CFR 431.343.

H. Effective and Compliance Dates

    The effective date for the adopted test procedure amendment will be 
75 days after publication of this final rule in the Federal Register. 
EPCA prescribes that 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 180 days after publication of the final rule in the Federal 
Register. (42 U.S.C. 6314(d)(1)) EPCA provides an allowance for 
individual manufacturers to petition DOE for an extension of the 180-
day period if the manufacturer may experience undue hardship in meeting 
the deadline. (42 U.S.C. 6314(d)(2)) To receive such an extension, 
petitions must be filed with DOE no later than 60 days before the end 
of the 180-day period and must detail how the manufacturer will 
experience undue hardship. (Id.)

[[Page 5552]]

I. Renumbering of Appendix A

    Currently, appendix A is organized using a hierarchy that uses 
Roman numerals (i.e., ``I, II, III, IV . . .'') for first-level 
headings, Latin capital letters for second-level headings (i.e., ``A, 
B, C, D . . .''), and Arabic numerals (i.e., 1, 2, 3 . . .'') for 
third-level headings.
    In this final rule, DOE is revising the numbering hierarchy of 
appendix A to use only Arabic numerals, consistent with the numbering 
hierarchy that DOE uses across test procedures for consumer products at 
10 CFR part 430, subpart B and for commercial and industrial equipment 
generally at 10 CFR part 431. For example, the current heading 
``I.B.2'' of appendix A is renumbered to ``2.2.2'' (also reflecting the 
addition of a new section at the beginning of appendix A). This 
renumbering is for consistency purposes only and does not result in any 
substantive changes solely as a result of the renumbering.

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866, 13563, and 14094

    Executive Order (``E.O.'') 12866, ``Regulatory Planning and 
Review,'' as supplemented and reaffirmed by E.O. 13563, ``Improving 
Regulation and Regulatory Review,'' 76 FR 3821 (Jan. 21, 2011) and E.O. 
14094, ``Modernizing Regulatory Review,'' 88 FR 21879 (April 11, 2023), 
requires agencies, to the extent permitted by law, to (1) propose or 
adopt a regulation only upon a reasoned determination that its benefits 
justify its costs (recognizing that some benefits and costs are 
difficult to quantify); (2) tailor regulations to impose the least 
burden on society, consistent with obtaining regulatory objectives, 
taking into account, among other things, and to the extent practicable, 
the costs of cumulative regulations; (3) select, in choosing among 
alternative regulatory approaches, those approaches that maximize net 
benefits (including potential economic, environmental, public health 
and safety, and other advantages; distributive impacts; and equity); 
(4) to the extent feasible, specify performance objectives, rather than 
specifying the behavior or manner of compliance that regulated entities 
must adopt; and (5) identify and assess available alternatives to 
direct regulation, including providing economic incentives to encourage 
the desired behavior, such as user fees or marketable permits, or 
providing information upon which choices can be made by the public. DOE 
emphasizes as well that E.O. 13563 requires agencies to use the best 
available techniques to quantify anticipated present and future 
benefits and costs as accurately as possible. In its guidance, the 
Office of Information and Regulatory Affairs (``OIRA'') in the Office 
of Management and Budget (``OMB'') has emphasized that such techniques 
may include identifying changing future compliance costs that might 
result from technological innovation or anticipated behavioral changes. 
For the reasons stated in this preamble, this final regulatory action 
is consistent with these principles.
    Section 6(a) of E.O. 12866 also requires agencies to submit 
``significant regulatory actions'' to OIRA for review. OIRA has 
determined that this final regulatory action does not constitute a 
``significant regulatory action'' under section 3(f) of E.O. 12866. 
Accordingly, this action was not submitted to OIRA for review under 
E.O. 12866.

B. Review Under the Regulatory Flexibility Act

    The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires 
preparation of a final regulatory flexibility analysis (FRFA) for any 
final rule where the agency was first required by law to publish a 
proposed rule for public comment, unless the agency certifies that the 
rule, if promulgated, will not have a significant economic impact on a 
substantial number of small entities. As required by Executive Order 
13272, ``Proper Consideration of Small Entities in Agency Rulemaking,'' 
67 FR 53461 (August 16, 2002), DOE published procedures and policies on 
February 19, 2003 to ensure that the potential impacts of its rules on 
small entities are properly considered during the 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. DOE reviewed this final rule under the 
provisions of the Regulatory Flexibility Act and the procedures and 
policies published on February 19, 2003.
    For manufacturers of compressors, 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. 13 CFR 
part 121. The size standards are listed by North American Industry 
Classification System (``NAICS'') code and industry description and are 
available at www.sba.gov/document/support-table-size-standards. 
Compressor manufacturing is classified under NAICS 333912, ``air and 
gas compressor manufacturing.'' The SBA sets a threshold of 1,000 
employees or less for an entity to be considered a small business in 
this category. This employment figure is enterprise-wide, encompassing 
employees at all parent, subsidiary, and sister corporations.
    To identify and estimate the number of small business manufacturers 
of equipment within the scope of this rulemaking, DOE conducted a 
market survey using available public information. DOE's research 
involved industry trade association membership directories (including 
CAGI), individual company and online retailer websites, and market 
research tools (e.g., Hoovers reports) to create a list of companies 
that manufacture equipment covered by this rulemaking. DOE additionally 
reviewed publicly available data, data available through market 
research tools, and contacted select companies on its list, as 
necessary, to determine whether they met the SBA's definition of a 
small business manufacturer. DOE screened out companies that do not 
offer equipment within the scope of this rulemaking, do not meet the 
definition of a ``small business,'' or are foreign owned and operated.
    DOE identified a total of 12 domestic small businesses 
manufacturing compressors. However, as previously stated, the 
amendments adopted in this final rule revise certain definitions and 
formulas to ensure the clarity and accuracy of existing requirements 
and procedures, and the amendments harmonize the DOE test procedure 
with existing industry practices, without requiring manufacturers to 
retest their compressors. DOE has determined that the adopted test 
procedure amendments would not impact testing costs otherwise 
experienced by manufacturers.
    Therefore, DOE concludes that the cost effects accruing from the 
final rule would not have a ``significant economic impact on a 
substantial number of small entities,'' and that the preparation of a 
FRFA is not warranted. DOE has submitted a certification and supporting 
statement of factual basis to the Chief Counsel for Advocacy of the 
Small Business Administration for review under 5 U.S.C. 605(b).

C. Review Under the Paperwork Reduction Act of 1995

    Manufacturers of compressors must certify to DOE that their 
products comply with any applicable energy conservation standards. To 
certify compliance, manufacturers must first

[[Page 5553]]

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 compressors. (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.
    DOE is not amending the certification or reporting requirements for 
compressors in this final rule. Instead, DOE may consider proposals to 
amend the certification requirements and reporting for compressors 
under a separate rulemaking regarding appliance and equipment 
certification. DOE will address changes to OMB Control Number 1910-1400 
at that time, as necessary.
    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 final rule, DOE establishes test procedure amendments that 
it expects will be used to develop and implement future energy 
conservation standards for compressors. 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 (August 4, 
1999), imposes certain requirements on agencies formulating and 
implementing policies or regulations that preempt State law or that 
have federalism implications. The Executive order requires agencies to 
examine the constitutional and statutory authority supporting any 
action that would limit the policymaking discretion of the States and 
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 examined this final 
rule and determined that it will 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 final 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. 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, 
this final 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 regulatory action resulting 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 www.energy.gov/gc/office-general-counsel. DOE examined this final 
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

[[Page 5554]]

proposed rule or policy that may affect family well-being. When 
developing a Family Policymaking Assessment, agencies must assess 
whether: (1) the action strengthens or erodes the stability or safety 
of the family and, particularly, the marital commitment; (2) the action 
strengthens or erodes the authority and rights of parents in the 
education, nurture, and supervision of their children; (3) the action 
helps the family perform its functions, or substitutes governmental 
activity for the function; (4) the action increases or decreases 
disposable income or poverty of families and children; (5) the proposed 
benefits of the action justify the financial impact on the family; (6) 
the action may be carried out by State or local government or by the 
family; and whether (7) the action establishes an implicit or explicit 
policy concerning the relationship between the behavior and personal 
responsibility of youth, and the norms of society. In evaluating the 
above factors, DOE has concluded that it is not necessary to prepare a 
Family Policymaking Assessment as none of the above factors are 
implicated. Further, this proposed determination would not have any 
financial impact on families nor any impact on the autonomy or 
integrity of the family as an institution.

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 regulation will 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 final 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 significant energy action. A 
``significant energy action'' is defined as any action by an agency 
that promulgates 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 is likely to have a 
significant adverse effect on the supply, distribution, or use of 
energy; or (2) is designated by the Administrator of OIRA as a 
significant energy action. For any significant energy action, the 
agency must give a detailed statement of any adverse effects on energy 
supply, distribution, or use if the regulation is implemented, and of 
reasonable alternatives to the action and their expected benefits on 
energy supply, distribution, and use.
    This regulatory action is not a significant regulatory action under 
Executive Order 12866. Moreover, it would not have a significant 
adverse effect on the supply, distribution, or use of energy, 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. 95-91; 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 modifications to the test procedure for compressors adopted in 
this final rule incorporate testing methods contained in certain 
sections of the following commercial standards: ISO 1217:2009(E), as 
amended through ISO 1217:2009(E)/Amd.1:2016. While this test procedure 
is not exclusively based on this industry testing standard, some 
components of the DOE test procedure adopt definitions, test 
parameters, measurement techniques, and additional calculations from 
them without amendment. DOE has evaluated these standards and is unable 
to conclude whether it fully complies 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.) In the 
January 2017 Final Rule, DOE consulted with both the Attorney General 
and the Chairman of the FTC about the impact on competition of using 
the methods contained in these standards and received no comments 
objecting to their use. 82 FR 1052, 1099.

M. Congressional Notification

    As required by 5 U.S.C. 801, DOE will report to Congress on the 
promulgation of this rule before its effective date. The report will 
state that it has been determined that the rule is not a ``major rule'' 
as defined by 5 U.S.C. 804(2).

N. Description of Materials Incorporated by Reference

    The following standards have not previously been approved for 
incorporation by reference in subpart T, appendix A, but are 
incorporated by reference in this final rule on the basis that they are 
referenced by other standards which had been previously and remain 
incorporated by reference in subpart T, appendix A.
    ISO 1217:2009(E), ``Displacement compressors--Acceptance tests,'' 
fourth edition, July 1, 2009. ISO 1217:2009(E) specifies methods for 
acceptance tests regarding volume rate of flow and power requirements 
of displacement compressors. It also specifies methods for testing 
liquid-ring type compressors and the operating and testing conditions 
which apply when a full performance test is specified.
    ISO 1217:2009/Amd.1:2016(E), Displacement compressors--Acceptance 
tests (fourth edition, July 1, 2009), AMENDMENT 1: Calculation of 
isentropic efficiency and relationship with specific energy, April 15, 
2016. ISO 1217:2009/Amd.1.:2016(E) provides a method for the 
calculation of isentropic efficiency and relationship with specific 
energy.
    ISO 5167-1:2022(E), Measurement of fluid flow by means of pressure 
differential devices inserted in circular cross-section conduits 
running full--Part 1: General principles and

[[Page 5555]]

requirements, third edition, June 2022. ISO 5167-1:2022(E) defines 
terms and symbols and establishes the general principles for methods of 
measurement and computation of the flow rate of fluid flowing in a 
conduit by means of pressure differential devices (orifice plates, 
nozzles, Venturi tubes, cone meters, and wedge meters) when they are 
inserted into a circular cross-section conduit running full. The 
standard also specifies the general requirements for methods of 
measurement, installation and determination of the uncertainty of the 
measurement of flow rate.
    ISO 9300:2022(E), Measurement of gas flow by means of critical flow 
nozzles, third editions, June 2022. ISO 9300:2022(E) specifies the 
geometry and method of use (installation in a system and operating 
conditions) of critical flow nozzles used to determine the mass flow 
rate of a gas flowing through a system basically without the need to 
calibrate the critical flow nozzle. It also gives the information 
necessary for calculating the flow rate and its associated uncertainty.
    IEC 60584-1:2013, Thermocouples--Part 1: EMF specifications and 
tolerances, edition 3.0, August 2013. IEC 60584-1:2013 specifies 
reference functions and tolerances for letter-designated thermocouples.
    IEC 60584-3:2021, Thermocouples--Part 3: Extension and compensating 
cables--Tolerances and identification system, edition 3.0, February 
2021. IEC 60584-3:2021 provides tolerances and an identification system 
necessary for the measurement of thermocouple circuits.
    In this final rule, DOE includes revisions to the regulatory text 
that contained references to section B.4.5 of Annex B of ISO 
1217:2009(E), which was not specifically incorporated by reference 
before this test procedure final rule.
    See SUPPLEMENTARY INFORMATION section of this document for 
availability information of this material.

V. Approval of the Office of the Secretary

    The Secretary of Energy has approved publication of this final 
rule.

List of Subjects in 10 CFR Part 431

    Administrative practice and procedure, Confidential business 
information, Energy conservation test procedures, Incorporation by 
reference, Reporting and recordkeeping requirements.

Signing Authority

    This document of the Department of Energy was signed on January 10, 
2025, by Jeffrey Marootian, Principal Deputy Assistant Secretary for 
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 January 13, 2025.
Treena V. Garrett,
Federal Register Liaison Officer, U.S. Department of Energy.

    For the reasons stated in the preamble, DOE amends part 431 of 
chapter II of title 10 of the Code of Federal Regulations 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.  431.342 by revising the definition of ``Air compressor'' 
to read as follows:

Sec.  431.342  Definitions concerning compressors.

* * * * *
    Air compressor means a compressor designed to compress air that has 
an inlet open to the atmosphere or other source of air, and is made up 
of one or more compression elements (bare compressors), driver(s), 
mechanical equipment to drive the compression elements, and any 
ancillary equipment.
* * * * *

0
3. Revise Sec.  431.343 to read as follows:

Sec.  431.343  Materials incorporated by reference.

    (a) 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, the DOE must publish a document in 
the Federal Register and the material must be available to the public. 
All approved incorporation by reference (IBR) 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, 1000 Independence Avenue SW, EE-5B, Washington, DC 20024, 
(202) 586-9127, [email protected], www.energy.gov/eere/buildings/building-technologies-office. For information on the availability of 
this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations.html or email: [email protected]. The material may be 
obtained from the sources in paragraphs (b) and (c) of this section:
    (b) IEC. International Electrotechnical Commission Central Office, 
3, rue de Varemb[eacute], Case Postale 131, CH-1211 GENEVA 20, 
Switzerland; + 41 22 919 02 11; webstore.iec.ch.
    (1) IEC 60584-1:2013, Thermocouples--Part 1: EMF specifications and 
tolerances, editions 3.0, August 2013; IBR approved for appendix A to 
this subpart.
    (2) IEC 60584-3:2021, Thermocouples--Part 3: Extension and 
compensating cables--Tolerances and identification system, edition 3.0, 
February 2021; IBR approved for appendix A to this subpart.
    (c) ISO. International Organization for Standardization, Chemin de 
Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland +41 22 749 01 
11, www.iso.org.
    (1) ISO 1217:2009(E), Displacement compressors--Acceptance tests, 
fourth edition, July 1, 2009; IBR approved for appendix A to this 
subpart.
    (2) ISO 1217:2009/Amd.1:2016(E), Displacement compressors--
Acceptance tests (fourth edition, July 1, 2009), AMENDMENT 1: 
Calculation of isentropic efficiency and relationship with specific 
energy, April 15, 2016; IBR approved for appendix A to this subpart.
    (3) ISO 5167-1:2022(E), Measurement of fluid flow by means of 
pressure differential devices inserted in circular cross-section 
conduits running full--Part 1: General principles and requirements, 
third edition, June 2022; IBR approved for appendix A to this subpart.
    (4) ISO 9300:2022(E), Measurement of gas flow by means of critical 
flow nozzles, third edition, June 2022; IBR approved for appendix A to 
this subpart.

0
4. Revise appendix A to subpart T to read as follows:

[[Page 5556]]

Appendix A to Subpart T of Part 431--Uniform Test Method for Certain 
Air Compressors.

    Note:  Prior to July 16, 2025, any representations made with 
respect to the energy use or efficiency of compressors must be based 
on testing conducted in accordance with:
    (a) The applicable provisions of this appendix as they appeared 
in this subpart T of part 431 as of January 1, 2023; or
    (b) This appendix.
    Beginning July 16, 2025, representations with respect to energy 
use or efficiency of compressors, including compliance 
certifications, must be based on testing conducted in accordance 
with this appendix.

1. Incorporation by Reference

    DOE incorporated by reference in Sec.  431.343, the entire 
standard for: IEC 60584-1:2013, IEC 60584-3:2021, ISO 1217:2009(E), 
ISO 1217:2009/Amd.1:2016(E), ISO 5167-1:2022, and ISO 9300:2022; 
however, only enumerated provisions of ISO 1217:2009(E) and ISO 
1217:2009/Amd.1:2016(E) are applicable to this appendix as listed in 
section 1. To the extent there is a conflict between the terms or 
provisions of a referenced industry standard and the CFR, the CFR 
provisions control.
    1.1 ISO 1217:2009(E)
    1.1.1 Section 2, Normative references;
    1.1.2 Section 3, Terms and definitions;
    1.1.3 Section 4, Symbols;
    1.1.4 Section 5, Measuring equipment, methods and accuracy 
(excluding 5.1, 5.5, 5.7, and 5.8);
    1.1.5 Section 6, Test procedures: the introductory text to 
Section 6.2, Test arrangements, paragraphs 6.2(g) and 6.2(h), and 
Table 1--Maximum deviations from specified values and fluctuations 
from average readings of this appendix;
    1.1.6 Annex B (normative), Simplified acceptance test for bare 
displacement compressors, Section B.4.5 Comparison with specified 
values;
    1.1.7 Annex C (normative), Simplified acceptance test for 
electrically driven packaged displacement compressors (excluding 
C.1.2, C.2.1, C.3, C.4.2.2, C.4.3.1, and C.4.5).
    1.2 ISO 1217:2009/Amd.1:2016(E)
    1.2.1 Section 3.5.1: isentropic power;
    1.2.2 Section 3.6.1: isentropic efficiency;
    1.2.3 Annex H (informative), Isentropic efficiency and its 
relation to specific energy requirement, sections H.2, Symbols and 
subscripts, and H.3, Derivation of isentropic power.

2. Measurements, Test Conditions, and Equipment Configuration

    2.1. Measurement Equipment.
    2.1.1. For the purposes of measuring air compressor performance, 
the equipment necessary to measure volume flow rate, inlet and 
discharge pressure, temperature, condensate, and packaged compressor 
power input must comply with the equipment and accuracy requirements 
specified in sections 5.2, 5.3, 5.4, 5.6, and 5.9 of ISO 
1217:2009(E), (including the applicable provisions of IEC 60584-1 
and IEC 60584-3, as referenced in section 5.3 of ISO 1217:2009(E) 
and the applicable provisions of ISO 5167-1 and ISO 9300, as 
referenced in section 5.6 of ISO 1217:2009(E)) and sections C.2.3 
and C.2.4 of Annex C to ISO 1217:2009(E).
    2.1.2. Electrical measurement equipment must be capable of 
measuring true root mean square (RMS) current, true RMS voltage, and 
real power up to the 40th harmonic of fundamental supply source 
frequency.
    2.1.3. Any instruments used to measure a particular parameter 
specified in section 2.1.1 of this appendix must have a combined 
accuracy of 2.0 percent of the measured value at the 
fundamental supply source frequency, where combined accuracy is the 
square root of the sum of the squares of individual instrument 
accuracies.
    2.1.4. Any instruments used to directly measure the density of 
air must have an accuracy of 1.0 percent of the measured 
value.
    2.1.5. Any pressure measurement equipment used in a calculation 
of another variable (e.g.,actual volume flow rate) must also meet 
all accuracy and measurement requirements of section 5.2 of ISO 
1217:2009(E).
    2.1.6. Any temperature measurement equipment used in a 
calculation of another variable (e.g.,actual volume flow rate) must 
also meet all accuracy and measurement requirements of section 5.3 
of ISO 1217:2009(E).
    2.1.7. Where ISO 1217:2009(E) refers to ``corrected volume flow 
rate,'' the term is deemed synonymous with the term ``actual volume 
flow rate,'' as defined in section 3.4.1 of ISO 1217:2009(E).

2.2. Test Conditions and Configuration of Unit Under Test

    2.2.1. For both fixed-speed and variable-speed compressors, 
conduct testing in accordance with the test conditions, unit 
configuration, and specifications of section 6.2 paragraphs (g) and 
(h) of ISO 1217:2009(E) and sections C.1.1, C.2.2, C.2.3, C.2.4, 
C.4.1, C.4.2.1, C.4.2.3, and C.4.3.2 of Annex C to ISO 1217:2009(E).
    2.2.2. The power supply must:
    (a) Maintain the voltage greater than or equal to 95 percent and 
less than or equal to 110 percent of the rated value of the motor,
    (b) Maintain the frequency within 5 percent of the 
rated value of the motor,
    (c) Maintain the voltage unbalance of the power supply within 
3 percent of the rated values of the motor, and
    (d) Maintain total harmonic distortion below 12 percent 
throughout the test.
    2.2.3. Ambient Conditions. The ambient air temperature must be 
greater than or equal to 68 [deg]F and less than or equal to 90 
[deg]F for the duration of testing. There are no ambient condition 
requirements for inlet pressure or relative humidity.
    2.2.4. All equipment indicated in table 1 of this appendix must 
be present and installed for all tests specified in this appendix. 
If the compressor is distributed in commerce without an item from 
table 1 of this appendix, the manufacturer must provide an 
appropriate item to be installed for the test. Additional ancillary 
equipment may be installed for the test, if distributed in commerce 
with the compressor, but this additional ancillary equipment is not 
required. If any of the equipment listed in table 2 of this appendix 
is distributed in commerce with units of the compressor basic model, 
it must be present and installed for all tests specified in this 
appendix.

                 Table 1--Equipment Required During Test
------------------------------------------------------------------------
                                                        Variable-speed
            Equipment             Fixed-speed rotary      rotary air
                                    air compressors       compressors
------------------------------------------------------------------------
Driver..........................  Yes...............  Yes.
Bare compressors................  Yes...............  Yes.
Inlet filter....................  Yes...............  Yes.
Inlet valve.....................  Yes...............  Yes.
Minimum pressure check valve/     Yes...............  Yes.
 backflow check valve.
Lubricant separator.............  Yes...............  Yes.
Air piping......................  Yes...............  Yes.
Lubricant piping................  Yes...............  Yes.
Lubricant filter................  Yes...............  Yes.
Lubricant cooler................  Yes...............  Yes.
Thermostatic valve..............  Yes...............  Yes.
Electrical switchgear or          Yes...............  Not applicable.*
 frequency converter for the
 driver.
Device to control the speed of    Not applicable **.  Yes.
 the driver (e.g., variable
 speed drive).
Compressed air cooler(s)........  Yes...............  Yes.
Pressure switch, pressure         Yes...............  Yes.
 transducer, or similar pressure
 control device.

[[Page 5557]]

 
Moisture separator and drain....  Yes...............  Yes.
------------------------------------------------------------------------
* This category is not applicable to variable-speed rotary air
  compressors.
** This category is not applicable to fixed-speed rotary air
  compressors.

Table 2--Equipment Required During Test, if Distributed in Commerce With
                             the Basic Model
------------------------------------------------------------------------
                                                        Variable-speed
            Equipment             Fixed-speed rotary      rotary air
                                    air compressors       compressors
------------------------------------------------------------------------
Cooling fan(s) and motors.......  Yes...............  Yes.
Mechanical equipment............  Yes...............  Yes.
Lubricant pump..................  Yes...............  Yes.
Interstage cooler...............  Yes...............  Yes.
Electronic or electrical          Yes...............  Yes.
 controls and user interface.
All protective and safety         Yes...............  Yes.
 devices.
------------------------------------------------------------------------

    2.2.5. The inlet of the compressor under test must be open to 
the atmosphere and take in ambient air for all tests specified in 
this appendix.
    2.2.6. The compressor under test must be set up according to all 
manufacturer instructions for normal operation (e.g., verify 
lubricant level, connect all loose electrical connections, close off 
bottom of unit to floor, cover forklift holes).
    2.2.7. The piping connected to the discharge orifice of the 
compressor must be of a diameter at least equal to that of the 
compressor discharge orifice to which it is connected. The piping 
must be straight with a length of at least 6 inches.
    2.2.8. Transducers used to record compressor discharge pressure 
must be located on the discharge piping between 2 inches and 6 
inches, inclusive, from the discharge orifice of the compressor. The 
pressure tap for transducers must be located at the highest point of 
the pipe's cross section.

3. Determination of Package Isentropic Efficiency, Package Specific 
Power, and Pressure Ratio at Full-Load Operating Pressure

    3.1 Data Collection and Analysis.
    3.1.1. Stabilization. Record data at each load point under 
steady-state conditions. Steady-state conditions are achieved when a 
set of two consecutive readings taken at least 10 seconds apart and 
no more than 60 seconds apart are within the maximum permissible 
fluctuation from the average (of the two consecutive readings), as 
specified in table 1 of ISO 1217:2009(E) for--
    (a) Discharge pressure;
    (b) Temperature at the nozzle or orifice plate, measured per 
section 5.3 of ISO 1217:2009(E); and
    (c) Differential pressure over the nozzle or orifice plate, 
measured per section 5.2 of ISO 1217:2009(E).
    3.1.2. Data Sampling and Frequency. At each load point, record a 
minimum set of 16 unique readings, collected over a minimum time of 
15 minutes. Each consecutive reading must be no more than 60 seconds 
apart, and not less than 10 seconds apart. All readings at each load 
point must be within the maximum permissible fluctuation from 
average specified in table 1 of ISO 1217:2009(E) for--
    (a) Discharge pressure;
    (b) Temperature at the nozzle or orifice plate, measured per 
section 5.3 of ISO 1217:2009(E); and
    (c) Differential pressure over the nozzle or orifice plate, 
measured per section 5.2 of ISO 1217:2009(E).
    If one or more readings do not meet the requirements, then all 
previous readings must be disregarded and a new set of at least 16 
new unique readings must be collected over a minimum time of 15 
minutes. Average the readings to determine the value of each 
parameter to be used in subsequent calculations.
    3.1.3. Calculations and Rounding. Perform all calculations using 
raw measured values. Round the final result for package isentropic 
efficiency to the thousandth (i.e., 0.001), for package specific 
power in kilowatts per 100 cubic feet per minute to the nearest 
hundredth (i.e., 0.01), for pressure ratio at full-load operating 
pressure to the nearest tenth (i.e., 0.1), for full-load actual 
volume flow rate in cubic feet per minute to the nearest tenth 
(i.e., 0.1), and for full-load operating pressure in pounds per 
square inch gauge (psig) to the nearest integer (i.e., 1). All terms 
and quantities refer to values determined in accordance with the 
procedures set forth in this appendix for the tested unit.

3.2. Full-Load Operating Pressure and Full-Load Actual Volume Flow Rate

    Determine the full-load operating pressure and full-load actual 
volume flow rate (referenced throughout this appendix) in accordance 
with the procedures prescribed in section 4 of this appendix.

3.3. Full-Load Package Isentropic Efficiency for Fixed- and Variable-
Speed Air Compressors

    Use this test method to test fixed-speed air compressors and 
variable-speed air compressors.
    3.3.1. Test unit at full-load operating pressure and full-load 
volume flow rate according to the requirements established in 
sections 2, 3.1, and 3.2 of this appendix. Measure volume flow rate 
and calculate actual volume flow rate in accordance with section 
C.4.2.1 of Annex C to ISO 1217:2009(E) with no corrections made for 
shaft speed. Measure discharge gauge pressure and packaged 
compressor power input. Measured discharge gauge pressure and 
calculated actual volume flow rate must be within the deviation 
limits for discharge pressure and volume flow rate specified in 
tables C.1 and C.2 of Annex C to ISO 1217:2009(E), where full-load 
operating pressure and full-load actual volume flow rate (as 
determined in section 4 of this appendix) are the targeted values.
    3.3.2. Calculate the package isentropic efficiency at full-load 
operating pressure and full-load actual volume flow rate (full-load 
package isentropic efficiency, [eta]isen,FL) using the 
equation for isentropic efficiency in section 3.6.1 of ISO 
1217:2009(E) as modified by ISO 1217:2009/Amd.1:2016(E). For 
Pisen, use the isentropic power required for compression 
at full-load operating pressure and full-load actual volume flow 
rate, as determined in section 3.3.2.1 of this appendix. For 
Preal, use the real packaged compressor power input at 
full-load operating pressure and full-load actual volume flow rate, 
as determined in section 3.3.2.2 of this appendix.
    3.3.2.1. Calculate the isentropic power required for compression 
at full-load operating pressure and full-load actual volume flow 
rate using equation (H.6) of Annex H to ISO 1217:2009/Amd.1:2016(E). 
For qV1, use the actual volume flow rate 
(cubic meters per second) calculated in section 3.3.1 of this 
appendix. For p1, use 100 kPa. For p2, use the 
sum of
    (a) 100 kPa, and
    (b) The measured discharge gauge pressure (Pa) from section 
3.3.1 of this appendix. For K, use the isentropic exponent (ratio of 
specific heats) of air, which, for the purposes of this test 
procedure, is 1.400.
    3.3.2.2. Calculate real packaged compressor power input at full-
load operating pressure and full-load actual volume flow rate using 
the following equation:

Preal,100% = K5 [middot] K6 
[middot] PPR,100

Where:

[[Page 5558]]

    K5 = correction factor for inlet pressure, as 
determined in section C.4.3.2 of Annex C to ISO 1217:2009(E). For 
calculations of this variable use a value of 100 kPa for contractual 
inlet pressure;
    K6 = correction factor for pressure ratio, as 
determined in section B.4.5 of Annex B to ISO 1217:2009(E). For 
calculations of this variable use a value of 1.400 for isentropic 
exponent, and for contractual pressure ratio, use the ratio of (a) 
The sum of 100 kPa and the measured discharge gauge pressure (kPa) 
from section 3.3.1 of this appendix, to
    (b) 100 kPa; and
PPR,100 = packaged compressor power input reading 
at full-load operating pressure and full-load actual volume flow 
rate measured in section 3.3.1 of this appendix (W).

3.4. Part-Load Package Isentropic Efficiency for Variable-Speed Air 
Compressors
    Use this test method to test variable-speed air compressors.
    3.4.1. Test unit at two load points:
    (a) Full-load operating pressure and 70 percent of full-load actual 
volume flow rate and
    (b) Full-load operating pressure and 40 percent of full-load actual 
volume flow rate, according to the requirements established in sections 
2, 3.1, and 3.2 of this appendix. To reach each specified load point, 
adjust the speed of the driver and the backpressure of the system. For 
each load point, measure volume flow rate and calculate actual volume 
flow rate in accordance with section C.4.2.1 of Annex C to ISO 
1217:2009(E), with no corrections made for shaft speed. For each load 
point, measure discharge gauge pressure and packaged compressor power 
input. Measured discharge gauge pressure and calculated actual volume 
flow rate must be within the deviation limits for discharge pressure 
and volume flow rate specified in tables C.1 and C.2 of Annex C to ISO 
1217:2009(E).
    3.4.2. For variable-speed compressors, calculate the part-load 
package isentropic efficiency using the following equation:

[eta]isen,PL = v40 x 
[eta]isen,40 + v70 x 
[eta]isen,70 + v100 x 
[eta]isen,100

Where:

[eta]isen,PL = part-load package isentropic efficiency 
for a variable-speed compressor;
[eta]isen,100 = package isentropic efficiency at 
full-load operating pressure and 100 percent of full-load actual 
volume flow rate, as determined in section 3.3.2 of this appendix;
[eta]isen,70 = package isentropic efficiency at 
full-load operating pressure and 70 percent of full-load actual 
volume flow rate, as determined in section 3.4.3 of this appendix;
[eta]isen,40 = package isentropic efficiency at 
full-load operating pressure and 40 percent of full-load actual 
volume flow rate, as determined in section 3.4.4 of this appendix;
v40 = weighting at 40 percent of full-load actual 
volume flow rate and is 0.25;
v70 = weighting at 70 percent of full-load actual 
volume flow rate and is 0.50; and
v100 = weighting at 100 percent of full-load 
actual volume flow rate and is 0.25.

    3.4.3. Calculate package isentropic efficiency at full-load 
operating pressure and 70 percent of full-load actual volume flow rate 
using the equation for isentropic efficiency in section 3.6.1 of ISO 
1217:2009(E) as modified by ISO 1217:2009/Amd.1:2016(E). For 
Pisen, use the isentropic power required for compression at 
full-load operating pressure and 70 percent of full-load actual volume 
flow rate, as determined in section 3.4.3.1 of this appendix. For 
Preal, use the real packaged compressor power input at full-
load operating pressure and 70 percent of full-load actual volume flow 
rate, as determined in section 3.4.3.2 of this appendix.
    3.4.3.1. Calculate the isentropic power required for compression at 
full-load operating pressure and 70 percent of full-load actual volume 
flow rate using equation (H.6) of Annex H to ISO 1217:2009/
Amd.1:2016(E). For qV1, use actual volume flow rate (cubic 
meters per second) at full-load operating pressure and 70 percent of 
full-load actual volume flow rate, as calculated in section 3.4.1 of 
this appendix. For p1, use 100 kPa. For p2, use 
the sum of
    (a) 100 kPa, and
    (b) Discharge gauge pressure (Pa) at full-load operating pressure 
and 70 percent of full-load actual volume flow rate, as calculated in 
section 3.4.1 of this appendix. For K, use the isentropic exponent 
(ratio of specific heats) of air, which, for the purposes of this test 
procedure, is 1.400.
    3.4.3.2. Calculate real packaged compressor power input at full-
load operating pressure and 70 percent of full-load actual volume flow 
rate using the following equation:

Preal,70 = K5 [middot] K6 
[middot] PPR,70

Where:

K5 = correction factor for inlet pressure, as determined 
in section C.4.3.2 of Annex C to ISO 1217:2009(E). For calculations 
of this variable use a value of 100 kPa for contractual inlet 
pressure;
K6 = correction factor for pressure ratio, as determined 
in section B.4.5 of Annex B to ISO 1217:2009(E). For calculations of 
this variable use a value of 1.400 for isentropic exponent, and for 
contractual pressure ratio, use the ratio of
    (a) The sum of 100 kPa and the measured discharge gauge pressure 
(kPa) from the test at 70 percent of full-load actual volume flow 
rate in section 3.4.1 of this appendix, to
    (b) 100 kPa; and

PPR,70 = packaged compressor power input reading 
at full-load operating pressure and 70 percent of full-load actual 
volume flow rate, as measured in section 3.4.1 of this appendix (W).

    3.4.4. Calculate package isentropic efficiency at full-load 
operating pressure and 40 percent of full-load actual volume flow rate 
using the equation for isentropic efficiency in section 3.6.1 of ISO 
1217:2009(E) as modified by ISO 1217:2009/Amd.1:2016(E). For 
Pisen, use the isentropic power required for compression at 
full-load operating pressure and 40 percent of full-load actual volume 
flow rate, as determined in section 3.4.4.1 of this appendix. For 
Preal, use the real packaged compressor power input at full-
load operating pressure and 40 percent of full-load actual volume flow 
rate, as determined in section 3.4.4.2 of this appendix.
    3.4.4.1. Calculate the isentropic power required for compression at 
full-load operating pressure and 40 percent of full-load actual volume 
flow rate using equation (H.6) of Annex H to ISO 1217:2009/
Amd.1:2016(E). For qV1, use actual volume flow rate (cubic 
meters per second) at full-load operating pressure and 40 percent of 
full-load actual volume flow rate, as calculated in section 3.4.1 of 
this appendix. For p1, use 100 kPa. For p2, use 
the sum of
    (a) 100 kPa, and
    (b) Discharge gauge pressure (Pa) at full-load operating pressure 
and 40 percent of full-load actual volume flow rate, as calculated in 
section 3.4.1 of this appendix. For K, use the isentropic exponent 
(ratio of specific heats) of air, which, for the purposes of this test 
procedure, is 1.400.
    3.4.4.2. Calculate real packaged compressor power input at full-
load operating pressure and 40 percent of full-load actual volume flow 
rate using the following equation:

Preal,40 = K5 [middot] K6 
[middot] PPR,40

Where:

K5 = correction factor for inlet pressure, as determined 
in section C.4.3.2 of Annex C to ISO 1217:2009(E). For calculations 
of this variable use a value of 100 kPa for contractual inlet 
pressure;
K6 = correction factor for pressure ratio, as determined 
in section B.4.5 of Annex B to ISO 1217:2009(E). For calculations of 
this variable use a value of 1.400 for isentropic exponent, and for 
contractual pressure ratio, use the ratio of
    (a) The sum of 100 kPa and the measured discharge gauge pressure 
(kPa) from the test at 40 percent of full-load actual volume flow 
rate in section 3.4.1 of this appendix, to
    (b) 100 kPa; and

PPR,40 = packaged compressor power input reading 
at full-load operating pressure and 40 percent of full-load actual 
volume

[[Page 5559]]

flow rate, as measured in section 3.4.1 of this appendix (W).
3.5. Determination of Package Specific Power
    For both fixed and variable-speed air compressors, determine the 
package specific power, at any load point, using the equation for 
specific energy consumption in section C.4.4 of Annex C to ISO 
1217:2009(E) and other values measured pursuant to this appendix, with 
no correction for shaft speed. Calculate PPcorr in section 
C.4.4 of Annex C to ISO 1217:2009(E) using the following equation:

PPcorr = K5 [middot] K6 [middot] 
PPR

Where:

K5 = correction factor for inlet pressure, as determined 
in section C.4.3.2 of Annex C to ISO 1217:2009(E). For calculations 
of this variable use a value of 100 kPa for contractual inlet 
pressure;
K6 = correction factor for pressure ratio, as determined 
in section B.4.5 of Annex B to ISO 1217:2009(E). For calculations of 
this variable use a value of 1.400 for isentropic exponent, and for 
contractual pressure ratio, use the ratio of
    (a) The sum of 100 kPa and the measured discharge gauge pressure 
(kPa) from the test used to determine the package specific power, to
    (b) 100 kPa; and
PPR = packaged compressor power input reading (W), as 
determined in section C.2.4 of Annex C to ISO 1217:2009(E).
3.6. Determination of Pressure Ratio at Full-Load Operating Pressure
    Pressure ratio at full-load operating pressure, as defined in Sec.  
431.342, is calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TR17JA25.094

Where:

PR = pressure ratio at full-load operating pressure;
P1 = 100 kPa; and
PFL = full-load operating pressure, determined in section 
4.3.4 of this appendix (Pa gauge).

4. Method To Determine Maximum Full-Flow Operating Pressure, Full-Load 
Operating Pressure, and Full-Load Actual Volume Flow Rate

4.1. Principal Strategy
    The principal strategy of this method is to incrementally increase 
discharge pressure by 2 psig relative to a starting point, and identify 
the maximum full-flow operating pressure at which the compressor is 
capable of operating. The maximum discharge pressure achieved is the 
maximum full-flow operating pressure. The full-load operating pressure 
and full-load actual volume flow rate are determined based on the 
maximum full-flow operating pressure.
4.2. Pre-test Instructions
    4.2.1. Safety. For the method presented in section 4.3.1 of this 
appendix, only test discharge pressure within the safe operating range 
of the compressor, as specified by the manufacturer in the installation 
and operation manual shipped with the unit. Make no changes to safety 
limits or equipment. Do not violate any manufacturer-provided motor 
operational guidelines for normal use, including any restriction on 
instantaneous and continuous input power draw and output shaft power 
(e.g., electrical rating and service factor limits).
4.2.2. Adjustment of Discharge Pressure
    4.2.2.1. If the air compressor is not equipped, as distributed in 
commerce by the manufacturer, with any mechanism to adjust the maximum 
discharge pressure output limit, proceed to section 4.2.3 of this 
appendix.
    4.2.2.2. If the air compressor is equipped, as distributed in 
commerce by the manufacturer, with any mechanism to adjust the maximum 
discharge pressure output limit, then adjust this mechanism to the 
maximum pressure allowed, according to the manufacturer's operating 
instructions for these mechanisms. Mechanisms to adjust discharge 
pressure may include, but are not limited to, onboard digital or analog 
controls, and user-adjustable inlet valves.
    4.2.3. Driver speed. If the unit under test is a variable-speed 
compressor, maintain maximum driver speed throughout the test. If the 
unit under test is a fixed-speed compressor with a multi-speed driver, 
maintain driver speed at the maximum speed throughout the test.
4.2.4. Measurements and Tolerances
    4.2.4.1. Recording. Record data by electronic means such that the 
requirements of section 4.2.4.5 of this appendix are met.
    4.2.4.2. Discharge Pressure. Measure discharge pressure in 
accordance with section 5.2 of ISO 1217:2009(E). Express compressor 
discharge pressure in psig in reference to ambient conditions, and 
record it to the nearest integer. Specify targeted discharge pressure 
points in integer values only. The maximum allowable measured deviation 
from the targeted discharge pressure at each tested point is 1 psig.
    4.2.4.3. Actual Volume Flow Rate. Measure actual volume flow rate 
in accordance with section C.4.2.1 of Annex C to ISO 1217:2009(E) 
(where it is called ``corrected volume flow rate'') with no corrections 
made for shaft speed. Express compressor actual volume flow rate in 
cubic feet per minute at inlet conditions (cfm).
    4.2.4.4. Stabilization. Record data at each tested load point under 
steady-state conditions, as determined in section 3.1.1 of this 
appendix.
    4.2.4.5. Data Sampling and Frequency. At each load point, record a 
set of at least of two readings, collected at a minimum of 10 seconds 
apart. All readings at each load point must be within the maximum 
permissible fluctuation from the average (of the two consecutive 
readings), as specified in 3.1.2 of this appendix. Average the 
measurements to determine the value of each parameter to be used in 
subsequent calculations.
    4.2.5 Adjusting System Backpressure. Set up the unit under test so 
that backpressure on the unit can be adjusted (e.g., by valves) 
incrementally, causing the measured discharge pressure to change, until 
the compressor is in an unloaded condition.
    4.2.6 Unloaded Condition. A unit is considered to be in an unloaded 
condition if capacity controls on the unit automatically reduce the 
actual volume flow rate from the compressor (e.g., shutting the motor 
off, or unloading by adjusting valves).
4.3. Test Instructions
    4.3.1. Adjust the backpressure of the system so the measured 
discharge pressure is 90 percent of the expected maximum full-flow 
operating pressure, rounded to the nearest integer, in psig. If the 
expected maximum full-flow operating pressure is not known, then adjust 
the backpressure of the system so that the measured discharge pressure 
is 65 psig. Allow the unit to remain at this setting for 15 minutes to 
allow the unit to thermally stabilize. Then measure and record 
discharge pressure and actual volume flow rate at the starting 
pressure.
    4.3.2. Adjust the backpressure of the system to increase the 
discharge pressure by 2 psig from the previous value, allow the unit to 
remain at this setting for a minimum of 2 minutes, and proceed to 
section 4.3.3 of this appendix.
    4.3.3. If the unit is now in an unloaded condition, end the test 
and proceed to section 4.3.4 of this appendix. If the unit is not in an 
unloaded condition, measure discharge pressure and actual volume flow 
rate, and repeat section 4.3.2 of this appendix.

[[Page 5560]]

    4.3.4. Of the discharge pressures recorded under stabilized 
conditions in sections 4.3.1 through 4.3.3 of this appendix, identify 
the largest. This is the maximum full-flow operating pressure. 
Determine the full-load operating pressure as a self-declared value 
greater than or equal to the lesser of (A) 90 percent of the maximum 
full-flow operating pressure, or (B) 10 psig less than the maximum 
full-flow operating pressure.
    4.3.5 The full-load actual volume flow rate is the actual volume 
flow rate measured at the full-load operating pressure. If the self-
declared full-load operating pressure falls on a previously tested 
value of discharge pressure, then use the previously measured actual 
volume flow rate as the full-load actual volume flow rate. If the self-
declared full-load operating pressure does not fall on a previously 
tested value of discharge pressure, then adjust the backpressure of the 
system to the self-declared full-load operating pressure and allow the 
unit to remain at this setting for a minimum of 2 minutes. The measured 
actual volume flow rate at this setting is the full-load actual volume 
flow rate.

[FR Doc. 2025-01002 Filed 1-16-25; 8:45 am]
BILLING CODE 6450-01-P
```