Energy Conservation Program for Certain Commercial and Industrial Equipment: Test Procedure for Commercial Water Heating Equipment

Federal RegisterNov 10, 2016

Ask Donna

What actually matters in this document.

Text

DEPARTMENT OF ENERGY

10 CFR Parts 429, 430, and 431

[Docket No. EERE-2014-BT-TP-0008]

RIN 1904-AD18

Energy Conservation Program for Certain Commercial and Industrial Equipment: Test Procedure for Commercial Water Heating Equipment

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

On May 9, 2016, the U.S. Department of Energy (DOE) published a notice of proposed rulemaking (NOPR) to amend its test procedures for commercial water heaters, unfired hot water storage tanks, and hot water supply boilers (henceforth, “commercial water heating (CWH) equipment”). That proposed rulemaking serves as the basis for this final rule. Specifically, this final rule incorporates by reference the most recent versions of relevant industry standards; modifies the existing test methods for certain classes of CWH equipment; establishes new test procedures for determining the

efficiency of commercial heat pump water heaters and standby loss for instantaneous water heaters and hot water supply boilers; clarifies test set-up and settings for various classes of CWH equipment; revises the certification requirements for CWH equipment; and establishes associated definitions.

DATES:

The effective date of this rule is December 12, 2016. The final rule changes will be mandatory for representations related to energy efficiency or energy use starting November 6, 2017. The incorporation by reference of certain publications listed in this rule is approved by the Director of the

Federal Register

on December 12, 2016.

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:

https://www.regulations.gov/docket?D=EERE-2014-BT-TP-0008.

This Web page contains a link to the docket for this rulemaking on the

www.regulations.gov

site. The docket Web page contains simple 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) 586-6636 or by email:

CommWaterHeatingEquip2014TP0008@;ee.doe.gov.

FOR FURTHER INFORMATION CONTACT:

Ms. Ashley Armstrong, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Office, EE-5B, 1000 Independence Avenue SW., Washington, DC 20585-0121. Telephone: (202) 586-6590. Email:

Ashley.Armstrong@ee.doe.gov.

Mr. Eric Stas or Ms. Jennifer Tiedeman, U.S. Department of Energy, Office of the General Counsel, GC-33, 1000 Independence Avenue SW., Washington, DC 20585-0121. Telephone: (202) 586-9507 or (202) 287-6111. Email:

Eric.Stas@hq.doe.gov

Jennifer.Tiedman@hq.doe.gov.

SUPPLEMENTARY INFORMATION:

This final rule incorporates by reference the following industry standards into part 431:

(1) American National Standards Institute, (ANSI) Standard Z21.10.3-2015/Canadian Standards Association (CSA) Standard 4.3-2015, “Gas-fired water heaters, volume III, storage water heaters with input ratings above 75,000 Btu per hour, circulating and instantaneous,” ANSI approved on October 5, 2015, Annex E (normative) Efficiency test procedures—E.1 “Method of test for measuring thermal efficiency,” Paragraph c, “Vent requirements” and Paragraph f, “Installation of temperature sensing means”;

(2) American Society of Heating, Refrigeration and Air-Conditioning Engineers, ANSI/ASHRAE Standard 118.1-2012, ANSI approved on October 27, 2012, “Method of Testing for Rating Commercial Gas, Electric, and Oil Service Water-Heating Equipment”; Section 3 “Definition and Symbols,” Section 4 “Classifications by Mode of Operation,” Section 6 “Instruments,” Section 7 “Apparatus,” Section 8 “Methods of Testing,” Section 9 “Test Procedures,” and Section 10 “Calculation of Results”;

(3) ASTM International (ASTM) C177-13, “Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus,” approved September 15, 2013;

(4) ASTM C518-15, “Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus,” approved September 1, 2015; and

(5) ASTM D2156-09 (Reapproved 2013), “Standard Test Method for Smoke Density in Flue Gases from Burning Distillate Fuels,” approved October 1, 2013.

Copies of ANSI Z21.10.3-2015/CSA 4.3-2015 and ANSI/ASHRAE 118.1-2012 can be obtained from the American National Standards Institute, 25 W. 43rd Street, 4th Floor, New York, NY 10036, (212) 642-4800, or by going to

http://webstore.ansi.org/.

Copies of ASTM C177-13, ASTM C518-15, and ASTM D2156-09 can be obtained from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, (610) 832-9585, or by going to

http://www.astm.org/Standard/index.html.

See section IV.N of this final rule for further discussion of these standards.

Table of Contents

I. Authority and Background

II. Synopsis of the Final Rule

III. Discussion

A. Updated Industry Test Methods

1. ANSI Z21.10.3 Testing Standard

2. ASTM Standard Test Method D2156 and Smoke Spot Test

3. ASTM Test Standards C177 and C518

B. Ambient Test Conditions and Measurement Intervals

1. Ambient Room Temperature

2. Test Air Temperature

3. Ambient Relative Humidity

4. Maximum Air Draft

5. Measurement Intervals

C. Test Set-Up for Storage and Storage-Type Instantaneous Water Heaters

D. Test Method for Unfired Hot Water Storage Tanks

E. Setting the Tank Thermostat for Storage and Storage-Type Instantaneous Water Heaters

1. Gas-fired and Oil-Fired Storage Water Heaters

2. Electric Storage Water Heaters

F. Steady-State Requirements and Soak-In Period

1. Steady-State Verification

2. Clarifying Statements

3. Soak-In Period

G. Definitions for Certain Consumer Water Heaters and Commercial Water Heating Equipment

1. Consumer Water Heaters

2. Commercial Water Heating Equipment

3. Residential-Duty Commercial Water Heaters

4. Storage-Type Instantaneous Water Heaters

H. Standby Loss Test for Instantaneous Water Heaters and Hot Water Supply Boilers

1. Definition of Flow-Activated Instantaneous Water Heater

2. Storage Volume Determination for Instantaneous Water Heaters and Hot Water Supply Boilers (Excluding Storage-Type Instantaneous Water Heaters)

3. Standby Loss Test Procedures for Instantaneous Water Heaters and Hot Water Supply Boilers (Other Than Storage-Type Instantaneous Water Heaters)

I. Test Set-Up for Commercial Instantaneous Water Heaters and Hot Water Supply Boilers

1. Location of Outlet Water Temperature Measurement

2. Multiple Outlet Water Connections

3. Supply and Outlet Water Valves

4. Additional Comments

5. Test Set-Up for Instantaneous Water Heaters and Hot Water Supply Boilers

J. Test Procedure for Rating Commercial Heat Pump Water Heaters

1. Definitions of CHPWH

2. Test procedure for CHPWH

K. Gas Pressure

L. Fuel Input Rate

1. Certification Provisions

2. Enforcement Provisions

M. Default Values for Certain Test Parameters for Commercial Water Heating Equipment

N. Certification Requirements

O. Other Issues

1. Timing of the Test Procedure and Energy Conservation Standards Rulemakings

2. Other Comments

3. Waiver Requests

IV. Procedural Issues and Regulatory Review

A. Review Under Executive Orders 12866

B. Review Under the Regulatory Flexibility Act

1. Need for, and Objectives of, the Rule

2. Significant Issues Raised in Response to the IRFA

3. Description and Estimate of the Number of Small Entities Affected

4. Description and Estimate of Compliance Requirements

5. Significant Alternatives to the Rule

C. Review Under the Paperwork Reduction Act of 1995

D. Review Under the National Environmental Policy Act of 1969

E. Review Under Executive Order 13132

F. Review Under Executive Order 12988

G. Review Under the Unfunded Mandates Reform Act of 1995

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

I. Review Under Executive Order 12630

J. Review Under the 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

Title III, Part C

of the Energy Policy and Conservation Act of 1975 (EPCA or the Act), Public Law 94-163 (42 U.S.C. 6311-6317, as codified), added by Public Law 95-619, Title IV, section 441(a), sets forth a variety of provisions designed to improve energy efficiency.

It established the “Energy Conservation Program for Certain Industrial Equipment,” a program covering certain commercial and industrial equipment (hereafter referred to as “covered equipment”), which includes the commercial water heating (CWH) equipment that is the subject of this rulemaking. (42 U.S.C. 6311(1)(K)) Title III, Part B

of EPCA (42 U.S.C. 6291-6309, as codified) sets forth a variety of provisions designed to improve energy efficiency and established the Energy Conservation Program for Consumer Products Other Than Automobiles. This includes consumer water heaters, which are also addressed in this rulemaking. (42 U.S.C. 6292(a)(4))

For editorial reasons, Part C was codified as Part A-1 in the U.S. Code.

All references to EPCA in this document refer to the statute as amended through the Energy Efficiency Improvement Act of 2015 (EEIA 2015), Public Law 114-11 (April 30, 2015).

For editorial reasons, upon codification in the U.S. Code, Part B was redesignated as Part A.

Under EPCA, the energy conservation programs for consumer products and industrial equipment generally consist of four parts: (1) Testing; (2) labeling; (3) establishing Federal energy conservation standards; and (4) certification and enforcement procedures. The testing requirements consist of test procedures that manufacturers of covered products and equipment must use as both the basis for certifying to DOE that their products and equipment comply with the applicable energy conservation standards adopted pursuant to EPCA, and for making representations about the efficiency of that equipment. (42 U.S.C. 6293(c); 42 U.S.C. 6295(s); 42 U.S.C. 6314; 42 U.S.C. 6316)

The initial test procedures for CWH equipment were added to EPCA by the Energy Policy Act of 1992 (EPACT 1992), Public Law 102-486, and correspond to those referenced in ASHRAE and Illuminating Engineering Society of North America (IESNA) Standard 90.1-1989 (

i.e.,

ASHRAE Standard 90.1-1989) which went into effect on October 24, 1992. (42 U.S.C. 6314(a)(4)(A)) EPCA requires that if an industry test procedure that is referenced in ASHRAE Standard 90.1 is amended, DOE must amend its test procedure to be consistent with the amended industry test procedure, unless DOE determines that the amended test procedure is not reasonably designed to produce test results that reflect the energy efficiency, energy use, or estimated operating costs of the equipment during a representative average use cycle. In addition, DOE must determine that the amended test procedure is not unduly burdensome to conduct. (42 U.S.C. 6314(a)(2), (3) and (4)(B))

If DOE determines that a test procedure amendment is warranted, it must publish a proposed test procedure in the

Federal Register

and offer the public an opportunity to present oral and written comments. (42 U.S.C. 6314(b)(1)-(2)) When amending a test procedure, DOE must determine to what extent, if any, the proposed test procedure would alter the equipment's energy efficiency as determined under the existing test procedure. (42 U.S.C. 6293(e); 42 U.S.C. 6314(a)(4)(C))

The Energy Independence and Security Act of 2007 (EISA 2007), Public Law 110-140, amended EPCA to require that at least once every 7 years, DOE must review test procedures for each type of covered equipment, including CWH equipment, and either: (1) Amend the test procedures if the Secretary of Energy (Secretary) determines that the amended test procedures would more accurately or fully comply with the requirements of 42 U.S.C. 6314(a)(2)-(3),

or (2) publish a notice of determination not to amend a test procedure. (42 U.S.C. 6314(a)(1)(A)) Under this requirement, DOE must review the test procedures for CWH equipment no later than May 16, 2019, which is 7 years after the most recent final rule amending the Federal test method for CWH equipment.

This final rule satisfies the requirement to review the test procedure for CWH equipment within 7 years, as well as the aforementioned requirement that DOE amend its test procedure if an industry test procedure is updated.

42 U.S.C. 6314(a)(2) requires that test procedures be reasonably designed to produce test results which reflect energy efficiency, energy use, and estimated operating costs of a type of industrial equipment (or class thereof) during a representative average use cycle (as determined by the Secretary), and not be unduly burdensome to conduct.

42 U.S.C. 6314(a)(3) requires that if the test procedure is a procedure for determining estimated annual operating costs, such procedure must provide that such costs are calculated from measurements of energy use in a representative average-use cycle (as determined by the Secretary), and from representative average unit costs of the energy needed to operate such equipment during such cycle. The Secretary must provide information to manufacturers of covered equipment regarding representative average unit costs of energy.

DOE published a final rule in the

Federal Register

on May 16, 2012, that, in relevant part, amended its test procedure for commercial water heating equipment. 77 FR 28928.

DOE's test procedure for CWH equipment is found at 10 CFR 431.106,

Uniform test method for the measurement of energy efficiency of commercial water heaters and hot water supply boilers (other than commercial heat pump water heaters).

DOE's test procedure for CWH equipment provides a method for determining the thermal efficiency and standby loss of CWH equipment. In a direct final rule for test procedures for CWH equipment, DOE incorporated by reference certain sections of ANSI Standard Z21.10.3-1998 (ANSI Z21.10.3-1998),

Gas Water Heaters, Volume III, Storage Water Heaters With Input Ratings Above 75,000 Btu Per Hour, Circulating and Instantaneous.

69 FR 61974, 61983 (Oct. 21, 2004). On May 16, 2012, DOE published a final rule for certain commercial heating, air-conditioning, and water heating equipment in the

Federal Register

that, among other things, updated the test procedures for certain CWH equipment by incorporating by reference ANSI

Z21.10.3-2011. 77 FR 28928, 28996. These updates did not materially alter DOE's test procedure for CWH equipment.

DOE has reserved a place in its regulations for a test procedure for commercial heat pump water heaters at 10 CFR 431.107,

Uniform test method for the measurement of energy efficiency for commercial heat pump water heaters.

However, in this final rule, DOE is removing 431.107 and addressing the test method for commercial heat pump water heaters in Appendix E to Subpart G of 10 CFR 431.

The American Energy Manufacturing Technical Corrections Act (AEMTCA), Public Law 112-210, was signed into law on December 18, 2012, and amended EPCA to require that DOE publish a final rule establishing a uniform efficiency descriptor and accompanying test methods for consumer water heaters and certain CWH equipment. (42 U.S.C. 6295(e)(5)) AEMTCA required DOE to replace the current efficiency metric for consumer water heaters (energy factor) and the current efficiency metrics for commercial water heaters (thermal efficiency and standby loss) with a uniform efficiency descriptor. (42 U.S.C. 6295(e)(5)(C)) Further, AEMTCA required that the uniform efficiency descriptor and accompanying test method apply, to the maximum extent possible, to all water heating technologies currently in use and to future water heating technologies. (42 U.S.C. 6295(e)(5)(H)) However, AEMTCA allowed DOE to exclude from the uniform efficiency descriptor specific categories of covered water heaters that do not have residential uses, that can be clearly described, and that are effectively rated using the current thermal efficiency and standby loss descriptors. (42 U.S.C. 6295(e)(5)(F))

DOE published a final rule for test procedures for certain CWH equipment on July 11, 2014 (“July 2014 final rule”). 79 FR 40542. The July 2014 final rule modified the current consumer water heater metric (energy factor) to create uniform energy factor (UEF), the descriptor to be used as the uniform efficiency descriptor for all consumer water heaters and CWH equipment that have residential uses.

Id.

at 40544. The July 2014 final rule excluded CWH equipment from the uniform descriptor equipment that has no residential use, that can be clearly identified and described, and that is effectively rated using the current thermal efficiency and standby loss efficiency descriptors. In the July 2014 final rule, DOE defined and adopted a new test method for “residential-duty commercial water heaters,” which are commercial water heaters that have residential uses.

Id.

For this final rule for CWH equipment test procedures, DOE is only amending test procedures for the CWH equipment classes that are not “residential-duty commercial water heaters” as adopted in the July 2014 final rule.

On February 27, 2014, DOE published in the

Federal Register

a request for information (February 2014 RFI) to seek public comments on several issues associated with the current test procedure for CWH equipment. 79 FR 10999. On May 9, 2016, DOE published a NOPR proposing amendments to its procedures for certain CWH equipment (May 2016 NOPR). 81 FR 28588. The May 2016 NOPR considered and responded to comments received in response to the February 2014 RFI.

Although DOE did not consider amended test procedures for residential-duty commercial water heaters, DOE is amending the definition for “residential-duty commercial water heater,” as discussed in section III.G.3.

In this final rule, DOE responds to all comments received from interested parties in response to the proposals presented in the May 2016 NOPR, either during the May 2016 NOPR public meeting or in subsequent written comments.

II. Synopsis of the Final Rule

As explained in detail in section III, in this final rule, DOE amends subpart G of 10 CFR part 431 to:

• Incorporate by reference certain provisions of the most current version of the following industry standards, older versions of which are currently incorporated into DOE's regulations: (1) ANSI Z21.10.3-2015/CSA 4.3-2015,

Gas-fired Water Heaters, Volume III, Storage Water Heaters with Input Ratings Above 75,000 Btu Per Hour, Circulating and Instantaneous

; (2) ASTM Standard Test Method D2156-09,

Standard Test Method for Smoke Density in Flue Gases from Burning Distillate Fuels

; (3) ASTM Standard Test Method C177-13,

Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus

; and (4) ASTM Test Standard Method C518-15,

Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus

;

• Update the requirements for ambient condition requirements, measurement locations, and measurement intervals for the thermal efficiency and standby loss test procedures;

• Amend the test set-up requirements for storage water heaters, storage-type instantaneous water heaters, instantaneous water heaters, and hot water supply boilers;

• Update provisions for setting the tank thermostat for storage and storage-type instantaneous water heaters prior to the thermal efficiency and standby loss tests;

• Update requirements for establishing steady-state operation for CWH equipment;

• Update existing and adopt new definitions for certain consumer water heaters, certain CWH equipment, residential-duty commercial water heater and storage-type instantaneous water heaters;

• Update the test set-up for instantaneous water heaters and hot water supply boilers that are tested using a recirculating loop;

• Adopt a new standby loss test procedure for flow-activated and externally-activated instantaneous water heaters;

• Modify the standby loss test procedure for internally thermostatically-activated instantaneous water heaters;

• Update the test procedure for determination of storage volume for instantaneous water heaters and hot water supply boilers (other than storage-type instantaneous water heaters);

• Adopt requirements for gas supply pressure and gas outlet pressure of gas-fired CWH equipment;

• Adopt a new test procedure for rating commercial heat pump water heaters (CHPWHs) based on certain sections incorporated by reference from ANSI/ASHRAE Standard 118.1-2012,

Method of Testing for Rating Commercial Gas, Electric, and Oil Service Water-Heating Equipment;

• Adopt provisions for measurement and enforcement of fuel input rate; and

• Specify default values for certain parameters for testing oil-fired CWH equipment.

The final rule also amends 10 CFR part 429 to clarify certification requirements and enforcement procedures for certain CWH equipment, and amends certain definitions in 10 CFR part 430. Specifically, in 10 CFR part 430, this final rule removes the definitions of “Electric heat pump water heater” and “Gas-fired heat pump water heater,” and revises the definitions of “Electric instantaneous water heater,” “Electric storage water heater,” “Gas-fired instantaneous water heater,” “Gas-fired storage water heater,” “Oil-fired instantaneous water heater,” and “Oil-fired storage water heater.”

III. Discussion

Table III-1 presents the list of interested parties that submitted written comments in response to the May 2016 NOPR.

Table III-1—Interested Parties Providing Comment in Response to the May 2016 NOPR

Name

Abbreviation

Commenter type

A.O. Smith Corporation and Lochinvar, LLC

A.O. Smith

Air-Conditioning, Heating, and Refrigeration Institute

AHRI

American Gas Association and American Public Gas Association

Gas Associations

Appliance Standards Awareness Project and American Council for an Energy-Efficient Economy

Joint Advocates (ASAP and ACEEE)

Bock Water Heaters, Inc

Bock

Bradford White Corporation

Bradford White

Bradley Corporation

Bradley

California Investor Owned Utilities

CA IOUs

Earthlinked Technologies Inc

Earthlinked

Edison Electric Institute

EEI

GE Appliances

HTP, Inc

HTP

Lochinvar, LLC

Lochinvar

Northwest Energy Efficiency Alliance

NEEA

Raypak, Inc

Raypak

Rheem Corporation

Rheem

Rinnai America Corporation

Rinnai

* “IR”: Industry Representative; “M”: Manufacturer; “EA”: Efficiency/Environmental Advocate.

These interested parties commented on a range of issues, including those identified by DOE in the May 2016 NOPR, as well as other issues related to the proposed test procedure. The issues, the comments received, DOE's responses to those comments, and the resulting changes to the NOPR test procedure proposals for CWH equipment adopted in this final rule are discussed in the following subsections.

A. Updated Industry Test Methods

DOE's test procedure for measuring the energy efficiency for CWH equipment currently incorporates by reference the industry standard ANSI Z21.10.3-2011 at 10 CFR 431.105. Additionally, DOE lists ASTM Standard Test Methods D2156-80, C177-97, and C518-91 as sources of information and guidance in 10 CFR 431.104. DOE defines “ASTM Standard Test Method D2156-80” at 10 CFR 431.102, and points to this source in DOE's current test procedure at 10 CFR 431.106. DOE points to ASTM C177-97 and ASTM C518-91 in its definition of “R-value” at 10 CFR 431.102. In the May 2016 NOPR, DOE proposed to update the references to industry test methods to incorporate the most recent version available of each of these standards.

As described in section I, with respect to CWH equipment, EPCA initially directs DOE to use industry test methods as referenced in ASHRAE/IES Standard 90.1, “Energy Standard for Buildings Except Low-Rise Residential Buildings.” (42 U.S.C. 6314(a)(4)(A)) If and when such an industry test method is amended, EPCA requires that DOE amend its test procedure as necessary to be consistent with the amended industry test method unless it determines, by rule published in the

Federal Register

and supported by clear and convincing evidence, that the amended test procedure would be unduly burdensome to conduct or would not produce test results that reflect the energy efficiency, energy use, and estimated operating costs of that equipment during a representative average use cycle. (42 U.S.C. 6314(a)(2), (3) and (4)(B))

AHRI and Rheem stated that DOE is obligated to adopt generally accepted industry testing procedures and may only adopt an alternate procedure upon proving by clear and convincing evidence that the industry test standard is not designed to reflect the energy efficiency of the equipment being tested or is unduly burdensome to conduct. (AHRI, No. 26 at pp. 3-4, Rheem No. 34 at p. 2) AHRI argued that the May 2016 NOPR does not address this statutory requirement and instead shifts the burden of data production to the regulated industry, and further argued that DOE must quantify the benefits of the proposed test procedure over the industry test standards. (AHRI, No. 26 at pp. 3-4) Rheem asserted that the appropriate reason to amend the current Federal test procedure is the statutory requirement to amend the Federal test procedure whenever the industry-accepted test standard for commercial water heating equipment is amended, and recommended that DOE adopt the industry-accepted test procedure rather than amendments to it. Rheem added that, in its view, the proposed test procedures lack justification, are burdensome, and are contradictory to the requirements of Executive Order 12988, “Civil Justice Reform.” (Rheem, No. 34 at pp. 1-4) A. O. Smith stated that the proposed test procedure is not justified by empirical and qualitative data. (A. O. Smith, No. 27 at p. 1)

DOE does not agree with commenters' interpretations of the relevant statutory provisions at issue here. Under 42 U.S.C. 6314(a)(4)(B), when DOE is triggered by the amendment of an industry test method applicable to ASHRAE equipment, the Secretary is directed to undertake an assessment of that industry test method to determine whether amendments to the Federal test procedure are “necessary” to be “consistent” with the amended industry test method. (There may be cases where the industry standard-setting organization reviews its method and puts out a new version with minimal or no changes, in which case it may not be necessary for DOE to amend its own test procedure.) The term “consistent” does not equate to “identical,” so Congress envisioned that some differentiation from the industry standard may be necessary. However, in the event DOE determines that a more significant deviation from the industry test method is needed (

i.e.,

a change that would not be “consistent” with the industry method), the Secretary must determine by rule published in the

Federal Register

and supported by clear and convincing evidence that a Federal test procedure consistent with the industry test method would not meet the requirements of 42 U.S.C. 6314(a)(2) and (3). It is only in the latter case that the clear and convincing evidence standard would apply.

In DOE's experience, industry standard-setting bodies typically

undertake a thorough and professional approach to their test procedures. However, DOE must remain cognizant of its statutory duty to ensure that the Federal test method be consistent with the industry test method while meeting other statutory requirements at 42 U.S.C. 6314(a)(2)-(3) (including that the procedure produces test results that reflect the energy efficiency, energy use, and estimated operating costs of that equipment during a representative average use cycle and is not unduly burdensome to conduct). To the extent that DOE identifies provisions of the relevant industry test method that would produce inaccurate, inconsistent, or unrepeatable results, as demonstrated by DOE's testing or analysis, such results would be unlikely to reflect a product's representative average energy efficiency or use. Such findings would demonstrate that the industry test procedure would not meet the statutory requirements of 42 U.S.C. 6314(a)(2)-(3) without alteration, thereby justifying DOE's decision to modify the industry test procedure (or in certain instances, even to deviate from the industry test procedure entirely, in which case the clear and convincing evidence standard would apply). That is why DOE usually adopts certain sections of industry test methods rather than adopting industry methods wholesale and adjusts the industry test methods as needed to satisfy the aforementioned statutory requirements. Such is the case here, where DOE is adopting amended test procedures that are largely consistent with the industry test methods (parts of which are incorporated by reference), and any deviations from those industry test methods adopted in this final rule are intended to clarify the test method to ensure consistent application, improve repeatability, or make the test method more representative of the energy efficiency during a representative average use cycle, and ensure that the test procedure is not unduly burdensome to conduct.

DOE is tasked with providing clear, repeatable procedures through the rulemaking process. The differences between the Federal test methods that DOE is adopting in this final rule and the industry test methods, and the rationale for these differences, are explained in detail in the sections that follow. As one example, a major difference between the test method DOE is adopting in this final rule and the method contained in ANSI Z21.10.3-2015 is the method for setting the thermostat for gas-fired and oil-fired storage water heaters—DOE requires the thermostat be set based on the reading from the top-most thermostat, while ANSI Z21.10.3-2015 requires the thermostat be set based on the mean temperature of the water stored within the tank. As discussed in detail in section III.E.1 below, certain CWH designs having a large amount of stratification cannot achieve the mean tank temperature of 140 ± 5 °F required by ANSI Z21.10.3-2015. Thus, if DOE were to adopt the industry method wholesale, there would be certain models that could not be tested in accordance with the test procedure. Further, the thermostats of gas-fired and oil-fired storage water heaters are generally set in the field to deliver water at the temperature needed for the application, without regard to the mean temperature of the water stored within the tank, as it is typically not relevant to the user as long as the water at the outlet can meet the temperature requirement for the application. Therefore, for this particular example, the DOE test method adopted in this final rule differs from the industry standard only to the extent that it is appropriate for and can be used for all types of CWH equipment. This approach to amending test procedures both maintains consistency with the industry test method and ensures that the Federal test method meets the statutory requirements set forth above.

Nonetheless, assuming that DOE requires clear and convincing evidence for its amendments to industry standards here, DOE believes its findings fully satisfy that threshold. To explain that conclusion, DOE articulates how it understands the “clear and convincing evidence” concept to operate in the context of DOE's establishing of test procedures. A rulemaking procedure is unlike the context of litigation, where “clear and convincing” means that the evidence must “place in the ultimate factfinder an abiding conviction that the truth” of its conclusions is “highly probable.”

Nonetheless, DOE fully recognizes that whenever it must have “clear and convincing evidence” pursuant to 42 U.S.C. 6314(a), it needs a higher degree of confidence in its conclusions than would be required under the “preponderance” standard that ordinarily applies in agency rulemaking. In such matters, the administrative record, taken as a whole, must justify DOE in a strong conviction that its conclusions are highly likely to be correct.

Colorado

New Mexico,

467 U.S. 310, 316 (1984).

Because a test procedure rulemaking is not a litigation, the differences warrant some differences in how the “clear and convincing evidence” threshold operates. DOE both develops the record and reviews it to make findings. Also, as an agency tasked with setting policy, DOE is ordinarily expected to use its technical judgment.

For purposes of establishing test procedures under 42 U.S.C. 6314(a), “clear and convincing evidence” can include the same sorts of evidence that DOE would use in any other rulemaking. But DOE will conclude it has “clear and convincing evidence” only when it is strongly convinced that it is highly likely to have reached appropriate findings. With respect to the findings discussed in this rulemaking, DOE does have that strong conviction.

In addition, contrary to AHRI's assertion, DOE is under no statutory obligation to quantify the benefits of adopting improved test procedures other than to find that the test procedures are not unduly burdensome to conduct. In response to Rheem's suggestion that DOE simply adopt industry test methods without amendment, where the industry-based test procedure contains one or more provisions that would prevent it from generating results that meet the requirements of the statute, EPCA directs DOE to adopt a Federal test procedure that resolves the identified problem(s)—not to adopt the industry method unquestioned. See 42 U.S.C. 6314(a)(2), (3) and (4). For the example given above, the industry test method cannot be used without modification for certain CWH equipment, as those equipment are not designed to operate in the manner prescribed by the industry test method. Therefore, the energy efficiency resulting from the industry test method (if possible to test) would not reflect the energy efficiency of that equipment during a representative average use cycle, and in such instances EPCA requires DOE to modify the test procedure.

Consistent with this authority, DOE is adopting a test procedure that is generally consistent with the industry-based test procedure. The justification and evidence supporting each provision adopted is described in the sections that follow, including DOE's compliance with Executive Order 12988, which is addressed in section IV.F of this final rule.

The following subsections discuss revisions to DOE's test procedure for CWH equipment vis-à-vis these industry standards.

1. ANSI Z21.10.3 Testing Standard

As previously noted, DOE's test procedure for measuring the energy efficiency for CWH equipment currently incorporates by reference the industry

standard ANSI Z21.10.3-2011 at 10 CFR 431.105. Specifically, the DOE test procedures at 10 CFR 431.106 directs one to follow Exhibits G.1 and G.2 of ANSI Z21.10.3-2011 for measuring thermal efficiency and standby loss, respectively. An updated edition of the industry test method, ANSI Z21.10.3-2015/CSA 4.3-2015,

Gas-fired Water Heaters, Volume III, Storage Water Heaters with Input Ratings Above 75,000 Btu Per Hour, Circulating and Instantaneous

(hereinafter referred to as “ANSI Z21.10.3-2015”), was approved on October 5, 2015, and released in November 2015.

In the May 2016 NOPR, DOE proposed to incorporate by reference certain sections of ANSI Z21.10.3-2015 in its test procedures for CWH equipment. 81 FR 28588, 28595 (May 9, 2016). Specifically, DOE proposed to incorporate by reference only Annex E.1 of ANSI Z21.10.3-2015 (which corresponds to Exhibit G.1 of ANSI Z21.10.3-2011). As discussed in the May 2016 NOPR, DOE did not propose to incorporate by reference Annex E.2 of ANSI Z21.10.3-2015 (which corresponds to Exhibit G.2 of ANSI Z21.10.3-2011) because of an error in a standby loss equation; however, DOE included certain language from Annex E.2 in its standby loss test procedures proposed in the May 2016 NOPR.

Id.

DOE has concluded that the standby loss test procedure for storage-type CWH equipment adopted in this final rule is consistent with the approach taken by Annex E.2 of ANSI Z21.10.3-2015; nonetheless, any differences in the DOE test method (as discussed in the applicable subsections within section III of this notice) are also supported by clear and convincing evidence. CA IOUs responded to the May 2016 NOPR by expressing support for updating the reference to ANSI Z21.10.3-2015 with as-needed modifications. (CA IOUs, No. 23 at p. 1) In the May 2016 NOPR, DOE's proposed test procedures included specific references to sections c, f, and j of Annex E.1 of ANSI Z21.10.3-2015. 81 FR 28588, 28595 (May 9, 2016) However, as discussed in section III.F.1 of this final rule, DOE is adopting new requirements for establishing steady-state operation prior to the thermal efficiency test, as recommended by several stakeholders. Therefore, in this final rule, DOE is not referencing section j of Annex E.1 of ANSI Z21.10.3-2015, which includes conduct of the thermal efficiency test and establishment of steady-state operation. However, DOE is adopting language and equations for determination of thermal efficiency that are similar to those included in section j of Annex E.1 of ANSI Z21.10.3-2015. Consequently, in this final rule DOE is amending its test procedures for CWH equipment by incorporating by reference sections c and f (“Vent requirements” and “Installation of temperature-sensing means,” respectively) of Annex E.1 of ANSI Z21.10.3-2015.

ANSI Z21.10.3-2015 also includes a new standby loss test procedure—Annex E.3,

Method of test for measuring standby loss for tube type instantaneous water heaters with 10 or greater gallons of storage.

This procedure provides a method to test standby loss of instantaneous water heaters and hot water supply boilers, including those that require continuous flow of water to activate the burner or heating element (

i.e.,

“flow-activated instantaneous water heaters”). DOE reviewed this test procedure for the May 2016 NOPR and discussed the issues with incorporating Annex E.3 of ANSI Z21.10.3-2015 as a test procedure for conducting the standby loss test for flow-activated instantaneous water heaters. Specifically, DOE noted that Annex E.3 of ANSI Z21.10.3-2015 contained several apparent errors, such as equations that appeared to have typos and variables that were incorrectly defined. Further, the test method in Annex E.3 would have ended the test after 1 hour, and assumed that the entire amount of thermal energy contained in the stored water above room temperature is lost in exactly 1 hour, regardless of the rate at which the equipment actually loses heat. DOE tentatively concluded that such a procedure would unfairly assume the same rate of standby losses for models that may lose heat at different rates, and would not be representative of the energy efficiency of this equipment. DOE discussed these issues in detail in section III.G of the May 2016 NOPR. Ultimately, in the May 2016 NOPR, DOE proposed a test procedure similar to Annex E.3 of ANSI Z21.10.3-2015 with modifications to: (1) The equation to calculate the standby loss; (2) the conduct of the test; (3) the parameters that need to be measured; and (4) the stopping criteria for the test. 81 FR 28588, 28607-28613 (May 9, 2016). In the May 2016 NOPR, DOE also proposed to adopt a different method for determining the storage volume for use in the standby loss calculation for flow-activated instantaneous water heaters than that specified by Annex E.3 of ANSI Z21.10.3-2015. Specifically, DOE proposed to use a weight-based method similar to the method specified in section 5.27 of ANSI Z21.10.3-2015, rather than the method included in section 5.28 of ANSI Z21.10.3-2015, which leaves the actual method for determining storage volume to the discretion of the test entity.

In section III.H of this final rule, DOE discusses the comments received from interested parties on the proposed test procedure for flow-activated instantaneous water heaters, including comments on the methodology used to determine the storage volume. In addition, based on the comments received, DOE has expanded the applicability of the adopted test procedure to externally thermostatically-activated instantaneous water heaters and modified the methodology to determine the storage volume to allow the measurement using calculations of physical (or design drawing) based dimensions. For additional details, see section III.H of this final rule.

2. ASTM Standard Test Method D2156 and Smoke Spot Test

DOE's current test procedure for oil-fired CWH equipment at 10 CFR 431.106 points to ASTM Standard Test Method D2156-80. Specifically, DOE requires that smoke in the flue does not exceed No. 1 smoke

as measured by the procedure in ASTM D2156-80. A more recent version of ASTM D2156 was approved on December 1, 2009, and reapproved on October 1, 2013. After reviewing D2156-80 and D2156-09 for the May 2016 NOPR, DOE tentatively concluded that no substantive changes were made between these versions in the test method for determining the smoke spot number, and therefore DOE proposed to incorporate by reference ASTM D2156-09 in its test procedures for oil-fired CWH equipment. 81 FR 28588, 28595 (May 9, 2016). In response to the May 2016 NOPR, several parties expressed support in updating references to ASTM D1246-09. (Bock, No. 19 at p. 1; AHRI, No. 26 at p. 13; A.O. Smith, No. 27 at p. 2) DOE did not receive any other comments on this proposal, and, therefore, DOE is incorporating by reference ASTM D2156-09 in its test procedures for oil-fired CWH equipment in appendices A, C, and E to subpart G of 10 CFR part 431.

The smoke scale, as described in ASTM D156, consists of ten spots numbered consecutively from 0 to 9, ranging in equal photometric steps from white through neutral shades of gray to black.

DOE's current requirement for the flue gas smoke spot number for oil-fired CWH equipment requires that the smoke in the flue does not exceed No. 1 smoke;

however, the regulations do not specify when during the test to determine the smoke spot number. To improve consistency and repeatability of testing CWH equipment, in the May 2016 NOPR, DOE proposed to specify when to conduct the smoke spot test. 81 FR 28588, 28596 (May 9, 2016). Specifically, DOE proposed to require determination of the smoke spot number after steady-state operation has been achieved, but prior to beginning measurement for the thermal efficiency test. For the thermal efficiency test, DOE proposed to require that the smoke spot number be determined after steady-state condition has been reached (with steady-state defined as being achieved when there is no variation of the outlet water temperature in excess of 2 °F over a 3-minute period). For the standby loss test, DOE proposed to require determination of the smoke spot number after the first cut-out

before beginning measurements for the standby loss test. DOE also proposed to require that the CO°reading, which is required to be measured when testing oil-fired CWH equipment under DOE's current test procedures specified at 10 CFR 431.106, also be measured at the time required for determination of the smoke spot number.

Cut-out refers to the de-activation of the burner or heating element following a control signal that the stored water is heated to the thermostat set-point temperature or the call for hot water has ended. The thermostat that signals the burner to activate or de-activate may be located inside the unit or outside the unit at a remote location (

e.g.,

in an external hot water storage tank).

DOE also proposed to clarify that the smoke spot test and measurement of CO

reading are required before each thermal efficiency test or standby loss test (as applicable) of oil-fired CWH equipment unless no settings on the water heater have been changed and the water heater has not been turned off since the end of a previously run efficiency test, in which case a second smoke spot test or CO

reading is not required prior to beginning another efficiency test (

i.e.,

thermal efficiency or standby loss).

Id.

In response to the May 2016 NOPR, AHRI commented that the CO

reading and smoke spot number should only be measured once when input rate of the burner is being set, not before both the thermal efficiency and standby loss tests. (AHRI, No. 26 at pp. 8-9) A.O. Smith agreed with DOE's proposal regarding when the smoke spot test and measurement of CO

reading are not required, and agreed with DOE's proposal that the same requirement for when to measure apply to both CO

reading and the smoke spot test. (A.O. Smith, No. 27 at p. 2) Bock agreed with the proposal regarding when to conduct the smoke spot measurement before the thermal efficiency test, but disagreed with the proposal regarding when to conduct the measurement prior to the standby loss test. Specifically, Bock stated that confining the smoke spot measurement to the short time period between the second cut-in

and second cut-out would add unnecessary complexity to the procedure, and that the timing of the second cut-in varies. Bock suggested measurement of the smoke spot number 15 minutes into initial warm-up, before the first cut-out. (Bock, No. 19 at p. 1)

Cut-in refers to the initiation of the burner or heating element operation based on a control signal to raise the temperature of stored hot water that has fallen below the required thermostat set-point temperature, or to meet an external demand for hot water.

In this final rule, DOE is adopting a requirement similar to its proposal that the smoke spot test and CO

reading measurement be conducted before beginning the thermal efficiency test. However, given DOE's updated requirements that establish a steady-state verification period immediately preceding the thermal efficiency test (discussed in section III.F.1 of this final rule), the testing body may not know when the steady-state verification period ends and the thermal efficiency test begins until after testing is complete. Therefore, DOE is requiring that the smoke spot test and CO

reading measurement must be conducted with the burner firing prior to beginning measurements for the steady-state verification period.

In response to AHRI, DOE notes that the determination of the smoke spot number and measurement of the CO

reading is only required before the standby loss test if a thermal efficiency test or standby loss test was not previously conducted, or if the settings have been changed or the water heater turned off after a previously conducted test. Therefore, if efficiency tests are conducted consecutively, and the water heater settings are not changed or the water heater turned off between tests, the method adopted in this final rule is in line with AHRI's suggestion that the smoke spot test only be required once.

DOE also recognizes that there may be a short time period between the second cut-in and second cut-out for determining the smoke spot number, and that the timing of the second cut-in may not be easily predictable. Therefore, DOE agrees with Bock that measurement of the smoke spot number prior to the first cut-out would be less burdensome. When conducting the standby loss test when a thermal efficiency test was not conducted immediately prior, the thermostat must be set for the standby loss test prior to the first cut-out, but there is no specified duration for warm-up. For oil-fired CWH equipment for which a test was not previously conducted (or for which settings on the water heater have changed since the previous test), DOE is therefore specifying that the smoke spot number be determined with the burner firing prior to beginning the standby loss test. DOE is not adopting a requirement that the smoke spot test number be determined after any specific time before beginning the standby loss test, because DOE recognizes that different models will take different amounts of time to warm up.

Additionally, DOE is adopting specifications for the test procedure for the set-up for measuring the smoke density for oil-fired CWH equipment, as proposed in the May 2016 NOPR. 81 FR 28588, 28641 (May 9, 2016). Specifically, DOE is establishing a requirement that the smoke-measuring device be connected to an open-ended tube, and that this tube must project into the flue by

1/4

1/2

of the pipe diameter. These requirements are the same as those specified for commercial space-heating boilers in AHRI 1500-2015, and DOE did not receive any comments related to this proposal.

3. ASTM Test Standards C177 and C518

DOE's current definition for “R-value” at 10 CFR 431.102 references two industry test methods: ASTM Standard Test Method C177-97 and ASTM Test Standard Method C518-91.

A more recent version of ASTM C177 was approved in September 2013 and published in October 2013 (ASTM C177-13). Additionally, a more recent version of ASTM C518 was approved in May 2010 and published in June 2010 (ASTM C518-10). After comparing both versions of each standard for the May 2016 NOPR, DOE tentatively concluded that, for both standards, there are no substantive differences in the procedures for measuring R-value between the new and old versions. Therefore, in the May 2016 NOPR, DOE proposed to incorporate by reference ASTM Standard Test Methods C177-13 and C518-10, and to update its references to these versions in the definition for “R-value” at 10 CFR 431.102. 81 FR 28588, 28592 (May 9, 2016).

In response to the May 2016 NOPR, several interested parties expressed support for updating references to ASTM C518 and C177. (Bradford White, No. 21 at p.1; AHRI, No. 26 at p. 13; A.

O. Smith, No. 27 at p. 2; Rheem, No. 34 at p. 4) DOE did not receive any other comments on this proposal, and, therefore, DOE is incorporating by reference ASTM Standard Test Method C177-13. However, since publication of the May 2016 NOPR, DOE became aware of a more recent version of ASTM C518 that was approved in September 2015 and published in December 2015, ASTM C518-15. After careful review, DOE has determined that there are no substantive differences between ASTM C518-10 and ASTM C518-15. DOE received no feedback which disagreed with DOE's proposal to update its reference to ASTM C518 to the 2010 version. Since the 2015 version of ASTM C518 is not substantially different than the 2010 version and in order to maintain up-to-date references to industry test methods, DOE is incorporating by reference the most recent version of the standard, ASTM C518-15.

B. Ambient Test Conditions and Measurement Intervals

To improve the repeatability of the thermal efficiency and standby loss tests in DOE's current test procedures for CWH equipment, DOE proposed several changes to its required ambient test conditions. These proposals included: (1) Tightening the ambient room temperature tolerance from ± 10.0 °F to ± 5.0 °F and the allowed variance from mean ambient temperature from ± 7.0 °F to ± 2.0 °F; (2) requiring measurement of test air temperature—the temperature of entering combustion air—and requiring that the test air temperature not vary by more than ± 5 °F from the ambient room temperature at any measurement interval during the thermal efficiency and standby loss tests for gas-fired and oil-fired CWH equipment; (3) establishing a requirement for ambient relative humidity of 60 percent ± 5 percent during the thermal efficiency and standby loss tests for gas-fired and oil-fired CWH equipment; (4) setting a maximum air draft requirement of 50 ft/min as measured prior to beginning the thermal efficiency or standby loss tests; and (5) decreasing the time interval for data collection from one minute to 30 seconds for the thermal efficiency test and from 15 minutes to 30 seconds for the standby loss test. 81 FR 28588, 28597 (May 9, 2016).

In response to the May 2016 NOPR, several stakeholders disagreed with DOE's proposals to tighten requirements on ambient conditions and argued that DOE's proposals would be overly burdensome to manufacturers. (Bock, No. 19 at p. 1; Bradford White, No. 21 at p. 3; CA IOUs, No. 23 at pp. 2-3; HTP, No. 24 at p. 1; AHRI, No. 26 at pp. 6-8; A.O. Smith, No. 27 at p. 2; Raypak, No. 28 at pp. 5-6; Bradley, NOPR Public Meeting Transcript, No. 20 at p. 33; Rheem, No. 34 at pp. 4-6) Bock stated that it supports using the procedures in the most updated versions of ANSI Z21.10.3 and ASHRAE 118.1. (Bock, No. 19 at p. 1) Bradford White further argued that the proposed changes are not merited because they would not affect efficiency ratings. (Bradford White, No. 21 at p. 3) CA IOUs stated that the proposed tightening of requirements would not provide a significant improvement in accuracy. (CA IOUs, No. 23 at pp. 2-3)

A.O. Smith suggested that DOE's proposed modifications to the required ambient conditions would be very difficult to meet with large equipment with significant makeup air requirements. A.O. Smith also pointed out that a model of CWH equipment with a rated input of 2 million Btu/h would consume fresh air at a rate of 400 cfm, and that there are over 30 models of CWH equipment on the market with a rated input of 2 million Btu/h or greater. (A.O. Smith, No. 27 at p. 2) AHRI, A.O. Smith, and Raypak argued that laboratories in which CWH equipment is typically tested have multiple ongoing activities, with doors opening and closing, and that conditioning air in such a facility to meet DOE's proposed ambient condition requirements would be unduly burdensome to manufacturers. (AHRI, No. 26 at p. 7; A.O. Smith, No. 27 at p. 2; Raypak, No. 28 at p. 6) Bradford White indicated that costs per manufacturer to laboratory upgrades required to meet DOE's proposed requirements would be hundreds of thousands of dollars or require purchase of environmental chambers which cost at least $120,000 each; AHRI suggested that the cost of complying with the proposed requirements would range from $250,000 to $1 million per manufacturer; Raypak suggested the cost to upgrade its facility would be $500,000 to $1.5 million; Rinnai suggested that meeting DOE's proposed requirements would require environmental chambers which cost more than $250,000 each; and Rheem suggested that the cost for laboratory upgrades would be greater than $500,000. (Bradford White, No. 21 at p. 3; AHRI, No. 26 at p. 7; Raypak, No. 28 at p. 6; Rinnai, No. 34 at p. 1; Rheem, No. 34 at p. 5) NEEA agreed with DOE's proposed ambient condition requirements and suggested that the requirements would improve the consistency of DOE's test procedures with little or no additional test burden. (NEEA, No. 30 at p. 2)

In light of comments received, DOE is not adopting the more stringent ambient conditions (

i.e.,

tighter tolerance on ambient room temperature, ambient relative humidity requirements) that were proposed in the May 2016 NOPR that may have added to test burden for manufacturers. Therefore, DOE considers these comments mitigated. However, DOE is adopting changes related to its other proposals regarding test air temperature, maximum air draft, and data collection intervals, and the specific actions that DOE is taking on each of the proposed requirements and the potential test burden associated with each action are discussed separately in detail in this section.

Joint Advocates suggested that DOE should require collection and reporting of data for relative humidity, air temperature, and barometric pressure. (Joint Advocates, No. 32 at p. 2) CA IOUs commented that DOE should consider the impact of barometric pressure on the results of efficiency testing of CWH equipment because it affects how much moisture can be held in air. CA IOUs also requested that DOE conduct an uncertainty analysis to demonstrate that tighter temperature and humidity tolerances are warranted. (CA IOUs, No. 23 at p. 3) DOE is not aware of any data demonstrating that barometric pressure significantly affects the measured efficiency for CWH equipment, and has therefore not found it necessary to regulate the ambient barometric pressure of test rooms for any heating products. In response to the May 2016 NOPR, no commenters provided such data. Therefore, DOE is not adopting barometric pressure requirements in this final rule. Furthermore, with regard to the Join Advocates suggestion, DOE notes that reported values resulting from testing are typically based on test results of a sample that contains two or more units, which could have slightly different relative humidity and air temperatures during testing. Manufacturers then report representative values in accordance with the requirements of 10 CFR 429. Because reported values for relative humidity and air temperature would be based on multiple unit samples and would not correspond to a single efficiency rating resulting from a specific set of ambient conditions, this information would be of little value to commercial consumers. Therefore, DOE is declining to adopt these reporting requirements at this time.

The following subsections discuss the specific comments on each of the proposed changes for the ambient test

conditions, along with DOE's response and decision.

1. Ambient Room Temperature

Bradford White, AHRI, and Rheem noted that DOE's proposal to tighten the ambient room temperature requirement from 75 °F ± 10.0 °F to 75 °F ± 5.0 °F would preclude the testing of both consumer water heaters and commercial water heating equipment in the same test laboratory, because DOE's test procedure for consumer water heaters requires that the ambient room temperature be maintained between 65 °F and 70 °F. (Bradford White, No. 19 at p. 3; AHRI, No. 26 at p. 7; Rheem, No. 34 at p. 5) While Bradford White, AHRI, and A.O. Smith argued that DOE's proposal to decrease the permitted variance from mean ambient temperature during testing from ± 7.0 °F to ± 2.0 °F would require costly upgrades to HVAC systems in testing facilities, they supported decreasing the allowed variance from ± 7.0 °F to ± 5.0 °F. (Bradford White, No. 19 at p. 3; AHRI, No. 26 at p. 7; A.O. Smith, No. 27 at p. 18) Bradford White further noted that most manufacturers could accommodate a decrease in the allowed variance to ± 5.0 °F using their existing laboratory HVAC systems. (Bradford White, No. 19 at p. 3) A.O. Smith further noted that decreasing the allowed variance to ± 5.0 °F would not be burdensome to manufacturers because rapid variations in supply air flow and temperature could be avoided. (A.O. Smith, No. 27 at p. 18)

DOE agrees with commenters that establishing a narrower range for ambient room temperature such that consumer water heaters and commercial water heating equipment cannot be tested at the same time could be overly burdensome to some manufacturers. Therefore, DOE is maintaining its current ambient room temperature requirement for testing of CWH equipment at 75 °F ± 10.0 °F. In light of comments from several commenters that a decrease in the permitted variance from mean ambient temperature during testing from ± 7.0 °F to ± 5.0 °F would not be burdensome to manufacturers, DOE is adopting a requirement that the ambient temperature must not vary from the mean temperature during testing by more than ± 5.0 °F. This requirement is consistent with the requirement in ANSI Z21.10.3-2015, but slightly more stringent to improve repeatability. Based on the comments received, DOE believes this change would not add undue burden and would improve the repeatability of the test.

In the May 2016 NOPR, DOE proposed that the ambient room temperature be measured at the same interval during the soak-in period as during the thermal efficiency and standby loss tests—30 seconds. 81 FR 28588, 28641, 289644 (May 9, 2016). However, DOE believes that measurement of the ambient room temperature at frequent intervals throughout the 12-hour soak-in period is unnecessary. Unlike for an efficiency test (

i.e.,

thermal efficiency or standby loss) or the steady-state verification period, measurements from the soak-in period are not used in calculation of an efficiency metric or in verification of steady-state operation. The purpose of the soak-in period is simply to allow the tank insulation of storage water heaters and storage-type instantaneous water heaters to reach thermal equilibrium between the ambient room temperature and the stored water temperature. DOE believes that as long as no actions are taken that would change the ambient room temperature during the soak-in period, the ambient room temperature need only be measured prior to beginning the soak-in period. Therefore, DOE is adopting a requirement that the ambient room temperature be maintained at 75 °F ± 10 °F during the soak-in period as measured prior to beginning the soak-in period, and that no actions be taken during the soak-in period that would cause the ambient room temperature to deviate from this range.

2. Test Air Temperature

In the May 2016 NOPR, DOE proposed to require measurement of test air temperature—the temperature of entering combustion air—and require that the test air temperature not vary by more than ± 5 °F from the ambient room temperature at any measurement interval during the thermal efficiency and standby loss tests for gas-fired and oil-fired CWH equipment. 81 FR 28588, 28597 (May 9, 2016). Bradford White and Raypak disagreed with DOE's proposed requirements for test air temperature. (Bradford White, No. 19 at pp. 3-4; Raypak, No. 28 at pp. 5-6) Bradford White and AHRI argued that measurement of test air temperature at each air inlet would be redundant given the required measurement of ambient room temperature, because DOE's ambient room temperature requirement would apply to entering combustion air. (Bradford White, No. 19 at pp. 3-4; AHRI, No. 26 at p. 8) Bradford White further argued that DOE's ambient room temperature requirement would apply to entering combustion air because most models of CWH equipment are tested with minimal vent length, and therefore the combustion air inlet would be very close to the water heater and location of ambient room temperature measurement. Bradford White also asserted that DOE's proposal would present complications for water heaters with air inlets on the bottom of the unit and for models that draw combustion air from the periphery of the water heater, and that at least three thermocouples would likely be needed in these cases to measure test air temperature. Braford White also stated that adding multiple additional thermocouples to a data acquisition system would be more burdensome than suggested by DOE. (Bradford White, No. 19 at pp. 3-4) AHRI commented that the requirement to measure test air temperature within 2 feet of the combustion air inlet would not be possible for models with concentric direct venting. AHRI also argued that measuring the test air temperature for each air inlet for water heaters with multiple air inlets would be an unnecessary burden, and that one properly located temperature sensor could adequately monitor incoming air temperature for such water heaters. (AHRI, No. 26 at pp. 7-8) Raypak questioned why DOE proposed to require measurement of test air temperature, arguing that it does not affect measured efficiency and that DOE has not provided evidence that test air temperature affects accuracy or repeatability of test results. (Raypak, No. 28 at pp. 5-6)

DOE believes that the temperature of entering combustion air, or test air temperature, can have a significant effect on the measured efficiency of a water heater. An increased combustion air temperature increases the enthalpy of the entering air to the water heater, and this increased combustion air enthalpy provides for additional heating of water that is not reflected in the calculation of thermal efficiency. While DOE's current test procedure for CWH equipment does include a requirement for ambient room temperature, this value is only measured at a single location. Therefore, it is possible that the air temperatures could differ between the locations of measurement of ambient room temperature and test air temperature. As mentioned by AHRI, some models of CWH equipment are tested with direct venting systems, and DOE notes that the combustion air intake vent for such equipment would likely not be located in the immediate vicinity of the CWH equipment. Therefore, measurement of ambient room temperature would not be representative of the test air temperature for such equipment. DOE notes that

Raypak did not provide a rationale to support its assertion that test air temperature does not affect the measured efficiency. DOE also notes that AHRI 1500-2015, the industry-consensus test standard for commercial packaged boilers, includes similar requirements for measurement of both ambient room temperature and test air temperature. DOE does not believe that there is a significant difference between testing CWH equipment and commercial packaged boilers that would make measuring and recording test air temperature overly burdensome for CWH equipment. DOE acknowledges that, in certain cases, the air inlet(s) to the water heater may be close enough to the required location for measurement of ambient room temperature that there may not be a significant difference in temperature measured at the two locations. However, after consultation with independent testing laboratories, requiring additional temperature sensors to a data acquisition system to record another air temperature measurement (or multiple measurements) for the combustion air does not appear to present a significant burden to manufacturers, as it would be a simple, one-time task.

In this final rule, for gas-fired and oil-fired CWH equipment, DOE is adopting a requirement that test air temperature be measured within 2 feet of the air inlet to the water heater. DOE also is adopting a requirement that the test air temperature may not vary by more than ± 5 °F from the ambient room temperature at any measurement interval during the thermal efficiency or standby loss tests, as applicable. DOE concludes that the additional requirements for test air temperature are consistent with the industry standard, ANSI Z21.10.3-2015, as these requirements do not change or conflict with any requirements in the industry standard. Instead, the requirements pertaining to test air temperature provide a more detailed approach to maintaining the room temperature and will ensure consistent and repeatable temperatures within the test area.

Regarding AHRI's comments with respect to measuring test air temperature for models with direct venting, DOE's intent by the phrase “air inlet to the water heater” in the proposed requirement was to refer to the site where combustion air enters either the water heater or air intake vent, if applicable. However, DOE acknowledges that more specific phrasing is warranted to clarify the measurement location for models tested with direct venting. Therefore, DOE is adopting language such that the test air temperature must be measured within two feet of the air inlet to the water heater or the inlet to the combustion air intake vent, as applicable.

In the May 2016 NOPR, DOE proposed a location for the measurement of the test air temperature for units without a dedicated air inlet. 81 FR 28588, 28597 (May 9, 2016). Specifically, DOE proposed that in this case, the test air temperature would be measured within two feet of a location on the water heater where combustion air would enter the unit. DOE believes that this provision provide adequate instruction as to how to test units that draw combustion air from the periphery of the water heater, which was raised as a potential issue by Bradford White. Therefore, DOE is adopting the language proposed in the May 2016 NOPR for how to measure test air temperature for units without a dedicated air inlet. For such a unit, the test air temperature must be measured within two feet of any location on the water heater where combustion air is drawn. Additionally, for such a unit, DOE's adopted requirements would only require measurement of test air temperature at one location, not three, as asserted by Bradford White. For example, if a unit draws combustion air through a gap between the burner tray and the bottom of the tank, then the test air temperature must be measured within two feet of that gap.

Regarding Bradford White's comment that test air temperature measurement would be complicated for units with an air inlet on the bottom of the water heater, DOE believes that its provisions adopted in this final rule adequately address this issue. For water heaters that draw air from the periphery of the bottom of the water heater, DOE's previously discussed provision for how to measure test air temperature for units without a dedicated air inlet would apply. DOE is unaware of any models of CWH equipment on the market with a dedicated air inlet on the bottom of the water heater (

i.e.,

in between the water heater bottom and the ground), and suspects that this would be a undesirable configuration, as the small clearance between the water heater bottom and the ground would likely obstruct adequate flow of entering combustion air. However, if such a configuration of CWH equipment exists, the test air temperature would be measured at any location within two feet of the air inlet on the bottom of the water heater under the procedure adopted in this final rule. DOE presumes that any clearance between the bottom of the water heater and the ground that is sufficiently large for providing adequate air flow would also be sufficiently large for installing a temperature sensor(s) for measurement of test air temperature.

DOE disagrees with AHRI that measurement of test air temperature should not be required at each air inlet for models of CWH equipment with multiple air inlets. For units that have multiple air inlets (such as stacked, modular units with multiple air inlets that each correspond to a separate burner and heat exchanger), DOE believes that the efficiency of the unit would be affected by the entering combustion air temperature to all air inlets, and that a requirement to measure test air temperature at each air inlet is justified. As previously discussed, DOE does not believe that installing multiple temperature sensors to measure test air temperature would present a significant burden to manufacturers. Therefore, DOE is adopting a requirement that test air temperature be measured at each air inlet for units with multiple air inlets, and that the specification for no variation of more than ± 5 °F from the ambient room temperature applies to the test air temperature measured at each air inlet.

Given the requirement to measure test air temperature within two feet of the air inlet to the water heater, the location of test air temperature measurement may be close to the water heater burner. Therefore, DOE suspects that the temperature sensor used to measure test air temperature might be subject to radiation from the burner. To prevent an impact from such radiation on the measurement of test air temperature, DOE is adopting a requirement that the temperature sensor used to measure test air temperature be shielded from radiation. DOE notes that such a requirement for shielding temperature measurement from radiation is included in ANSI Z21.10.3-2015 for the temperature sensor used to measure ambient room temperature. Additionally, DOE understands that shielding temperature measurements from radiation is common industry practice and would not present any significant burden to manufacturers.

3. Ambient Relative Humidity

In response to DOE's proposed requirements for ambient relative humidity, several commenters argued that relative humidity does not have an effect on results of efficiency testing of CWH equipment because the tests do not require collection of condensate. (Bradford White, No. 19 at p. 2; AHRI, No. 26 at p. 8; A.O. Smith, No. 27 at p. 2; Raypak, No. 28 at p. 6; Rinnai, No. 31

at p. 1) CA IOUs commented that the extent to which relative humidity affects the measured efficiency of condensing water heaters is unclear. (CA IOUs, No. 24 at p. 3) Joint Advocates suggested that relative humidity requirements should not apply to non-condensing gas-fired and oil-fired CWH equipment. (Joint Advocates, No. 32 at p. 2) Bradford White and Rheem commented that it would be difficult to meet DOE's proposed relative humidity requirements in all geographic locations at all times of the year, as these factors can result in significant variation in ambient relative humidity. (Bradford White, No. 21 at pp. 2-3; Rheem, No. 34 at p. 5) Rheem further argued that meeting DOE's proposed relative humidity requirements would likely require that a test room be maintained at a positive pressure, and asserted that it would be difficult to connect humidistats to a data acquisition system. Rheem also stated that a less stringent tolerance is needed for an ambient relative humidity requirement, and that more data showing any correlation between relative humidity and water heater performance are needed before DOE sets a requirement for relative humidity. (Rheem, No. 34 at p. 5)

In light of comments received, DOE has concluded that the potential burden of controlling ambient humidity is not justified at this time, given the amount of make-up air for combustion that would need to be conditioned to supply larger CWH equipment during testing. Manufacturers asserted that controlling the ambient humidity will not have a substantial impact on ratings and should not be held within a tolerance. In DOE's view any variation in the resulting energy efficiency rating from varying levels of ambient humidity would be adequately captured by the existing tolerances for both certification and enforcement in DOE's regulations. Therefore, DOE is not adopting a requirement that ambient relative humidity be maintained at any specific level for CWH equipment other than commercial heat pump water heaters. DOE is establishing a wet bulb temperature requirement for commercial heat pump water heaters based on relevant industry test standards, as discussed in section III.J of this final rule.

4. Maximum Air Draft

In the May 2016 NOPR, DOE proposed a maximum air draft requirement of 50 ft/min as measured prior to beginning the thermal efficiency or standby loss tests. 81 FR 28588, 28597 (May 9, 2016). Bradford White and A.O. Smith agreed with DOE's proposed maximum air draft requirement, but commented that the requirement should not necessitate the connection of the draft-measuring device to the data acquisition system. (Bradford White, No. 19 at p. 4; A.O. Smith, No. 27 at p. 17) A.O. Smith also stated that measurement of air draft may have a large uncertainty at 50 ft/min, and recommended that DOE assign a tolerance for the measurement of air draft and require the draft-measuring device to meet International Organization for Standardization (ISO) requirements. (A.O. Smith, No. 27 at p. 17) Raypak disagreed with DOE's proposed maximum air draft requirement, and argued that there is no evidence that such a requirement would affect results of testing of CWH equipment. Additionally, Raypak argued that most CWH manufacturers do not manufacture residential water heaters, and that DOE was therefore mistaken to presume that many CWH equipment manufacturers would not need to purchase devices for measuring air draft as these devices are already required for testing residential water heaters. (Raypak, No. 28 at p. 5) Rheem argued that DOE's proposed maximum air draft requirement would be appropriate for the standby loss test, but unnecessary for the thermal efficiency test. Rheem also asserted that maintaining a maximum air draft less than 50 ft/min would be difficult while also maintaining the stricter ambient conditions proposed by DOE in the May 2016 NOPR. (Rheem, No. 34 at p. 6)

In this final rule, DOE is adopting its proposed requirement for a maximum air draft of 50 ft/min to clarify the requirement in ANSI Z21.10.3-2015 that the test area be “protected from drafts.” Because ANSI Z21.10.3-2015 already includes a requirement for protecting the test area from drafts, DOE concludes that this change provides additional detail but is consistent with the industry standard. DOE believes that this clarification reduces ambiguity in ANSI Z21.10.3-2015 to allow for a more repeatable test. This requirement is also similar to the requirement that DOE adopted for testing consumer water heaters and certain commercial water heaters in the July 2014 final rule. 79 FR 40542, 40569 (July 11, 2014). Specifically, DOE is adopting a requirement that the air draft be measured prior to beginning the thermal efficiency and standby loss tests, within three feet of the jacket of the water heater, and that no actions can be taken during the conduct of the tests that would increase the air draft near the water heater being tested.

In response to Raypak's comment that there is no evidence that the air draft affects the performance of CWH equipment, DOE notes that Annex E.1 of ANSI Z21.10.3-2015 already requires that water heater placement in the test room shall be protected from drafts. DOE believes that if the draft had no impact on the test result, the industry test standard, ANSI Z21.10.3-2015, would not require the test to be done in an area protected from drafts. Therefore, DOE believes that there is an understanding amongst the majority of the industry that air draft from sources such as room ventilation registers, windows, or other external sources of air movement, during the test can affect the performance of CWH equipment. DOE also believes that 50 ft/min is a reasonable maximum value, as it is consistent with DOE's requirement for consumer water heaters. DOE also notes that many manufacturers of CWH equipment also manufacture consumer water heaters and residential-duty commercial water heaters. DOE identified at least 17 of 29 CWH equipment manufacturers (excluding rebranders) that also manufacture consumer water heaters or residential-duty commercial water heaters. For CWH equipment manufacturers who do not also manufacture water heaters subject to the Part 430, Appendix E test procedure (and therefore may not already have draft-measuring devices in their test labs), DOE expects the costs and burden associated with purchasing air draft-measuring devices that do not have the capability of connection to data acquisition system to be insignificant. DOE discusses the potential costs of these requirements as they pertain to small business manufacturers in section 0.

Regarding digital measurement of air draft, DOE's maximum air draft requirement does not require digital measurement. DOE is only adopting a requirement to measure the air draft once at the beginning of the test, so connection to a data acquisition system would be unnecessary. Additionally, DOE is not establishing any requirements on the type or accuracy of device used to measure the air draft. DOE notes that it currently prescribes a similar maximum air draft requirement for consumer and residential-duty commercial water heaters and has no such requirements on the draft-measuring device in that test procedure at appendix E to subpart B of 10 CFR part 430. DOE believes the test entity can determine the appropriate device and accuracy for this measurement.

Additionally, DOE is not establishing a tolerance on its maximum air draft requirement. DOE believes that a tolerance is unnecessary on a maximum value—the air draft must be no greater than 50 ft/min, but any draft below this value meets the requirement.

DOE acknowledges that the air draft may potentially have a greater impact on the results of the standby loss test than on those of the thermal efficiency test. However, once again noting the draft protection provision in ANSI Z21.10.3-2015, DOE has concluded that there may still be an effect on the results of the thermal efficiency test, and that the measurement of air draft, just once before the test begins, does not present a significant burden to manufacturers. Therefore, DOE is adopting the maximum air draft requirement for both the thermal efficiency and standby loss tests. DOE notes that it is not adopting in this final rule the more stringent ambient condition requirements (

i.e.,

narrower tolerance on ambient room temperature, requirement to maintain ambient relative humidity within a specified range) that Rheem argued would make the proposed maximum air draft requirement difficult to meet.

In the May 2016 NOPR, DOE proposed that the maximum draft requirement also apply to the soak-in period. 81 FR 28588, 28597 (May 9, 2016). However, DOE has determined that this requirement is not necessary for the soak-in period. The purpose of the maximum air draft requirement is to improve repeatability of the thermal efficiency and standby loss tests by preventing large air drafts that might cause significantly higher tank heat losses in some tests than in others. DOE believes that this concern does not apply to the soak-in period, the purpose of which is simply to establish thermal equilibrium in the tank insulation, and during which energy consumption is not measured. Therefore, DOE is not adopting a maximum air draft requirement for the soak-in period.

5. Measurement Intervals

Bradford White, AHRI, and Raypak opposed DOE's proposal to decrease the required data collection interval from 1 minute to 30 seconds for the thermal efficiency test and from 15 minutes to 30 seconds for the standby loss test. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 6-7; Raypak, No. 28 at pp. 6-7) A.O. Smith and Rheem opposed DOE's proposal to decrease the time interval to 30 seconds specifically for the standby loss test. (A.O. Smith, No. 27 at p. 19; Rheem, No. 34 at p. 5)

AHRI and Raypak stated that DOE did not provide evidence or data to suggest that decreasing the time interval would improve accuracy or affect efficiency. (AHRI, No. 26 at pp. 6-7; Raypak, No. 28 at pp. 6-7) AHRI argued that measurements every 15 minutes during the standby loss test are sufficient, and that, if a measurement is within tolerance at two consecutive 15-minute readings, then it is reasonable to assume that the measurement was maintained within tolerance during the entire 15-minute period between measurements. (AHRI, NOPR Public Meeting Transcript, No. 20 at pp. 32-33)

Bradford White argued that DOE's proposal would make data files large and difficult to analyze. (Bradford White, No. 19 at p. 4) To accommodate DOE's proposed time intervals for data collection, AHRI commented that some manufacturers might need to upgrade their facilities, and Raypak and Rheem argued that small manufacturers might need to purchase or upgrade data acquisition systems. (AHRI, No. 26 at pp. 6-7; Raypak, No. 28 at pp. 6-7; Rheem, No. 34 at p. 5) A.O. Smith argued that no readings other than time and temperature should be required at intervals that would necessitate connection to a data acquisition system because most other measurement devices used for testing CWH equipment are not designed to communicate with a data acquisition system. (A.O. Smith, No. 27 at p. 18) Raypak argued that the costs for connecting devices to a data acquisition system are 4-5 times higher than suggested by DOE in the May 2016 NOPR. (Raypak, No. 28 at pp. 6-7) Rheem further acknowledged that data collection intervals can be reduced with current equipment. A.O. Smith and Rheem also asserted that DOE's proposed reduced measurement interval would lead to an increased likelihood that tests would have to be re-run if any parameters were to fall out of the allowable range during the test. (A.O. Smith, No. 27 at p. 18; Rheem, No. 34 at p. 5)

DOE proposed requirements for more frequent data collection to improve the resolution of test data, and therefore, to ensure that test conditions are adequately met throughout the test. DOE disagrees with AHRI that a value can be assumed to be maintained within tolerance in a 15-minute period between readings when measurements at each 15-minute interval are within tolerance, which is further supported by the comments of Rheem and A.O. Smith. DOE believes that 15 minutes is a sufficiently long time for variation in any one of several parameters to potentially have a significant effect on measured standby loss. DOE notes that the standby loss test measures a significantly lower energy consumption than does the thermal efficiency test, and that the measured standby loss is therefore particularly sensitive to fluctuations in ambient conditions. Therefore, DOE believes that recording measurements every 15 minutes does not provide sufficient resolution of test data to ensure that the test results accurately capture the variability in the measurement and could lead to inaccurate and/or inconsistent results. A requirement for data collection every minute ensures that only momentary fluctuations outside of the ambient condition tolerances (

i.e.,

those that occur between consecutive 1-minute readings and are therefore unlikely to have an effect on the measured efficiency) are permitted under DOE's test procedure.

DOE disagrees that its proposed measurement intervals for data collection would make data analysis significantly more burdensome. Analysis of whether all parameters were maintained within their allowable tolerances during testing should be quick and simple in spreadsheet software, and the time required for such analysis should not depend on the number of data entries to any significant extent.

DOE also disagrees that its proposed measurement intervals would require costly upgrades to laboratory facilities. Given that DOE's proposed measurement interval was only slightly different from the current requirement included in Exhibit G.1 of ANSI Z21.10.3-2011 (which DOE currently incorporates by reference for the thermal efficiency test)—30 seconds vs. 1 minute—DOE does not believe that this provision will require any upgrades. The duration of the standby loss test exceeds 24 hours and can reach up to 48 hours; therefore, DOE does not believe that any manufacturers are performing this test without an automated data acquisition system. The one-time cost of a data acquisition system would likely be much less than the recurring labor costs of having a lab technician constantly monitor and record measurements every 15 minutes for every standby loss test for up to 48 hours. Bradford White and Rheem acknowledged that they use data acquisition systems in their facilities, and no stakeholders have commented to DOE that they do not use data acquisition systems for testing of CWH equipment. (Bradford White, Rheem, NOPR Public Meeting Transcript, No. 20 at pp. 43-44) Additionally, DOE does not believe that increasing the frequency of data collection would require any

significant upgrades to existing data acquisition systems. Rather, DOE believes that changing the measurement frequency would require a simple one-time software change and that the additional amount of data collected could be stored inexpensively given the low cost of computer storage. Additionally, DOE is not adopting any requirements in this final rule that would require measurement with a data acquisition system other than time and temperature.

DOE believes that more frequent data collection allows the capture of any variation in parameters that might affect the measured efficiency of CWH equipment. If variation is detected such that a parameter does not meet the DOE test procedure requirements, then DOE believes that re-running the test would be warranted. However, DOE acknowledges that there is a possibility that there could be momentary fluctuations in ambient conditions and/or water temperatures that do not have a significant effect on efficiency. In such a case, a single data point out of the allowable range of the DOE test procedure could require a test to be re-run. The likelihood of such a momentary fluctuation being captured in a test data point is directly proportional to the frequency of data collection. For this reason, DOE is not adopting the proposed 30-second data collection intervals and is instead maintaining the existing 1-minute data collection interval requirement for the thermal efficiency test and decreasing the required data collection interval for the standby loss test from 15 minutes to 1 minute. For the thermal efficiency test, the 1-minute time interval applies to the measurement of (1) ambient room temperature, (2) test air temperature, (3) supply water temperature, and (4) outlet water temperature. For the standby loss test, the 1-minute time interval applies to the measurement of (1) ambient room temperature, (2) test air temperature, (3) mean tank temperature for storage water heaters and storage type-instantaneous water heaters, and (4) outlet water temperature for instantaneous water heaters and hot water supply boilers other than storage type-instantaneous water heaters. DOE concludes that these changes to the data recording intervals improve repeatability, while maintaining consistency with the test method in ANSI Z21.10.3-2015.

This 1-minute data collection interval is consistent with the required 1-minute measurement interval for inlet and outlet water temperatures included in the 2011 and 2015 versions of ANSI Z21.10.3. For the standby loss test, DOE believes that the benefits of finer granularity in data collected from 1-minute intervals instead of 15-minute intervals will provide confirmation that variation in ambient conditions does not occur during the test that could have a significant impact on the measured standby loss. DOE believes that this benefit outweighs any potential burden that might occur from the possibility of having to re-run a test because momentary fluctuations of ambient conditions out of tolerance were captured that would not affect the measured standby loss.

As discussed in sections III.F.1 and III.L of this final rule, DOE is also adopting requirements that the gas consumption be measured at 10-minute intervals during the steady-state verification period and thermal efficiency test. These gas consumption measurements are used to determine fuel input rate. As discussed in section III.F.1 of this final rule, DOE does not expect its requirements that gas consumption be measured at 10-minute intervals during the steady-state verification period and thermal efficiency test to impose any significant burden on manufacturers.

C. Test Set-Up for Storage and Storage-Type Instantaneous Water Heaters

DOE's current test procedure for CWH equipment incorporates by reference the requirement in Exhibit G.1 of ANSI Z21.10.3-2011 that the inlet and outlet piping be immediately turned vertically downward from the connections on a tank-type water heater to form heat traps, and that the thermocouples for measuring supply and outlet water temperatures be installed before the inlet heat trap piping and after the outlet heat trap piping. DOE noted in the May 2016 NOPR that the absence of a clearly defined location for the thermocouples could contribute to variability in the test results. As a result, DOE proposed particular locations for installing the supply and outlet water temperature sensors based on piping distance from the water heater connections. Specifically, DOE proposed that the sensors be placed after a total vertical piping distance of 24 inches and total horizontal piping that is (1) two inches plus the piping distance between the water connection and the edge of the water heater with top and bottom openings for water connections and (2) 6 inches for horizontal opening water connections. DOE also provided separate figures for each configuration of storage water heaters (

i.e.,

top, bottom and horizontal opening water connections) and included them in the proposed appendix A to subpart G of part 431 of the regulatory text of the May 2016 NOPR. 81 FR 28588, 28598-28599 (May 9, 2016).

Rheem stated that it agrees with the standardization of the location of temperature measurements, but disagrees with the distance of 24 inches for measuring the water temperature. Rheem argued that having an outlet water temperature measured at the proposed distance would result in inclusion of the piping losses, which may also differ between the piping configurations and outlet water temperature sensor locations adopted by each lab, and recommended that the water temperature for storage water heaters should be measured at a distance of 5 inches away from the water heater to achieve comparable results with instantaneous water heaters. Last, Rheem stated that the proposed inlet water temperature location for CWH equipment with water connections on the side of the tank is not feasible in the case of some of its models that have inlet water openings only 6 inches above the floor. (Rheem, No. 34 at pp. 6-7)

DOE agrees with Rheem that the total piping distance from the water heater to the temperature sensors (particularly the outlet water temperature) should be consistent between both storage type and instantaneous type water heaters, so that any piping losses are comparable. In the May 2016 NOPR, DOE proposed to specify the measurement location for outlet water temperature at 5 inches from the enclosure for instantaneous water heaters, because that measurement was proposed to be used for both outlet water temperature for the thermal efficiency test and to approximate the water temperature of stored water within the heat exchanger for the standby loss test. 81 FR 28588, 28613-28615 (May 9, 2016) Thus, for the standby loss test, it was important for that measurement to occur close to the unit. However, as discussed in section III.I.1, in this final rule, DOE is adopting a separate temperature measurement location for measuring water to approximate the water temperature within the heat exchanger for the standby loss test, and for measuring the outlet water temperature for the thermal efficiency test. As a result, in section III.I.1 of this final rule, DOE has modified the test set-up for instantaneous water heaters and hot water supply boilers so that: (1) Outlet water temperature for the thermal efficiency test is measured at the second elbow in the outlet water piping; (2) heat exchanger outlet water temperature measured for the standby loss test is within one inch of the outlet water port

(inside or outside); and (3) total piping distance between the water heater and supply and outlet water temperature sensors is consistent with that specified in the test set-up for water heaters with horizontal opening water connections. Rather than change the location of the temperature measurements for storage water heaters, as suggested by Rheem, DOE changed the measurement location for instantaneous water heaters. By using separate temperature sensors to measure the outlet water temperature for the standby loss test (within one inch of outlet) and the thermal efficiency test (at the second elbow), it is no longer necessary to have a temperature sensor for the outlet water temperature that is as close as possible to the water heater. Further, the additional piping length allows installation of two elbows in the piping and the measurement of the water temperature downstream (for outlet) and upstream (for supply) of the heat traps that are required for the test set-up. Installing the outlet water temperature sensor for the thermal efficiency test at the second elbow ensures that the water flow will be well mixed, resulting in more accurate temperature readings (as recommended by stakeholders). For a detailed explanation on test set up for instantaneous water heaters and hot water supply boilers and DOE's responses to public comments, see section III.I of this final rule.

With regard to Rheem's concerns about piping losses if the outlet water temperature is measured at a piping distance of 30 inches away from the water heater, DOE notes that the current and the proposed test set up both require the water piping to be insulated up to a distance of 4 feet from the water connections, which should minimize piping losses. In addition, water heaters with large pipe diameters may not be able to install outlet water temperature sensors with two elbows in the piping (to yield sufficient flow mixing) at 5 inches from the water heater.

DOE also considered Rheem's other comments on the inability of certain water heater models with horizontal water connections, to meet the vertical piping distance of 24 inches as proposed in May 2016 NOPR for the inlet water connection. To address this issue, DOE is adopting a requirement that the vertical piping distance be 24 inches, unless 24 inches is not possible, in which case the maximum possible distance for a given water heater model must be used.

Based on the foregoing, DOE is adopting the test set-ups shown in Figures III.1, III.2, and III.3 for gas-fired and oil-fired storage water heaters and gas-fired and oil-fired storage-type instantaneous water heaters. In addition, DOE uses very similar test set-ups for other types of CWH equipment. Specifically, as discussed in section III.I.5, the set-up for instantaneous water heaters and hot water supply boilers is the same as shown in Figures III.1, III.2, and III.3, except that an outlet water valve and heat exchanger outlet temperature sensor are required. DOE has concluded that these changes are consistent with the approach in ANSI Z21.10.3-2015, but will provide additional specificity and improve test repeatability. The test set-ups for electric storage water heaters and storage-type instantaneous water heaters are similar to the test set-ups shown in Figures III.1, III.2, and III.3, with the only difference being that the outlet water temperature sensor is not present. An outlet water temperature sensor is not needed for testing electric storage water heaters and storage-type instantaneous water heaters, because the outlet water temperature is not measured during the conduct of the test.

BILLING CODE 6450-01-P

ER10NO16.005

ER10NO16.006

BILLING CODE 6450-01-C

D. Test Method for Unfired Hot Water Storage Tanks

EPCA defines an “unfired hot water storage tank” (UFHWST) as a tank used to store water that is heated externally. (42 U.S.C. 6311(12)(C)) The current Federal standard for this equipment type requires a minimum thermal insulation (R-value) of 12.5. 10 CFR 431.110. DOE defines “R-value” as the thermal resistance of insulating material as determined based on ASTM Standard Test Method C177-97 or ASTM Standard Test Method C518-91 and expressed in °F·ft

·h/Btu. 10 CFR 431.102. In section III.A.3 of this rulemaking, DOE updates references to these standards in its definition for “R-value” by incorporating by reference ASTM C177-13 and ASTM C518-15. In the May 2016 NOPR, DOE proposed to adopt a method for testing the standby loss for UFHWSTs in lieu of relying on the current R-value metric and ASTM standards. DOE received numerous comments on this topic, and is still considering those comments. Therefore, DOE will address the comments and its proposed test procedure for UFHWSTs in a separate rulemaking notice.

DOE is aware that some manufacturers ship UFHWSTs without insulation and that uninsulated UFHWSTs may or may not then be insulated on-site. In the May 2016 NOPR, DOE clarified that UFHWSTs shipped without insulation are not compliant with the Federal R-value standard. 81 FR 28588, 28601-28602 (May 9, 2016). All UFHWSTs must either be shipped insulated to the R-value standard or shipped together with insulation meeting the R-value standard. Manufacturers of UFHWSTs must certify that the insulation meets the R-value standard prescribed in 10 CFR 431.110, and this certification must be based on testing according to the methods prescribed in the R-value definition. A UFHWST manufacturer may demonstrate compliance with the insulation requirements either by conducting testing itself or by using test data from the insulation material producer. Further, manufacturers of UFHWSTs are responsible for retaining records of the underlying test data used for certification in accordance with current maintenance of records requirements set forth at 10 CFR 429.71.

In response to the May 2016 NOPR, Bock and Raypak disagreed with DOE's clarification that all UFHWSTs must be shipped insulated or with insulation. (Bock, No. 19 at p. 2; Raypak, No. 28 at p. 3) Bock argued that some units have to be shipped without insulation to allow entry into a building, and that requiring shipping with insulation will increase expense and in some cases prevent installation. (Bock, No. 19 at p. 2) Raypak argued that tank insulation might be damaged beyond repair in shipping, and then require re-installation of insulation in the field. Raypak further suggested that DOE allow UFHWSTs with a volume greater than 200 gallons to be field-insulated. (Raypak, No. 28 at p. 3)

DOE disagrees with the commenters that manufacturers can distribute UFHWSTs in commerce without insulation. The standard, which was set by statute, requires a minimum thermal insulation (R-value) of 12.5 for UFHWSTs. The covered equipment must be compliant at the time the manufacturer distributes it in commerce.

See

42 U.S.C. 6316, 6302. Therefore, if a manufacturer distributes a UFHWST without insulation, the manufacturer has distributed a UFHWST without a minimum thermal insulation of 12.5. DOE's interpretation gives manufacturers a great deal of flexibility and accommodates commenters' concerns that insulation already wrapped on the UFHWST may be damaged during shipment or that insulated UFHWSTs may not fit through the entryway to some buildings, as manufacturers can either ship the tank already wrapped in insulation or with insulation provided. Therefore, if there are any UFHWSTs that cannot be shipped already insulated, or if there are concerns of damage of insulation in shipping, then the insulation shipped with the unit can be applied upon

installation. All UFHWSTs of all storage volumes must satisfy this requirement. Accordingly, in this final rule, DOE reiterates that all UFHWSTs must be shipped insulated or with insulation such that the installed UFHWST will meet the minimum standard.

E. Setting the Tank Thermostat for Storage and Storage-Type Instantaneous Water Heaters

DOE's test procedure for measuring the energy efficiency of CWH equipment currently requires that the thermostat be set to achieve specific conditions for the mean tank temperature before the test may begin. In particular, section g of Exhibit G.1 of ANSI Z21.10.3-2011 (which is currently incorporated by reference into the DOE test procedure) requires that before starting testing, the thermostat setting must be adjusted such that, when starting with the water in the system at 70 °F ± 2 °F, the maximum mean tank temperature would be 140 °F ± 5 °F after the thermostat reduces the gas supply to a minimum.

1. Gas-Fired and Oil-Fired Storage Water Heaters

DOE understands that some units may have difficulty achieving the current mean tank temperature requirement (

e.g.,

condensing water heaters), and in the May 2016 NOPR, DOE proposed to modify its requirements for setting the tank thermostat. 81 FR 28588, 28604 (May 9, 2016). Specifically, DOE proposed to modify the thermal efficiency and standby loss test procedures for gas-fired and oil-fired storage water heaters and storage-type instantaneous water heaters to require that before starting the required soak-in period, the thermostat setting be adjusted such that, when starting with the water in the system at 70 ± 2 °F, the maximum outlet water temperature will be 140 °F ± 5 °F after the thermostat reduces the gas supply to a minimum.

In response to the May 2016 NOPR, DOE received comments from several interested parties. Joint Advocates and Rheem agreed with changing from a mean tank temperature requirement to an outlet water temperature requirement for fossil fuel-fired storage water heaters. (Joint Advocates, No. 32 at p. 2; Rheem, No. 34 at p. 8) However, Rheem also stated that outlet water temperature is a poor indicator of standby loss, and that mean tank temperature should be used to determine heat loss. (Rheem, No. 34 at p. 8) AHRI stated that measurement of outlet water temperature will not work for setting the tank thermostat if measured more than 2 feet downstream of the water heater outlet because water is not flowing when setting the thermostat. Instead, AHRI suggested that the six tank temperature sensors be installed in the tank at the beginning of the test, as is currently required in ANSI Z21.10.3-2015, and that the tank thermostat be set based on the reading from the topmost tank temperature sensor used to calculate mean tank temperature. (AHRI, No. 26 at p. 8) A.O. Smith stated that, for the thermal efficiency test, setting the tank thermostat is irrelevant as long as the water heater is firing at full input rate and meeting the outlet water temperature requirement. A.O. Smith further suggested that, in order to measure the outlet water temperature for standby loss, the measurement location needs to be inside the tank within one inch of the tank outlet. (A.O. Smith, No. 27 at p. 5) Bradford White stated that the same thermostat setting should be used for both thermal efficiency and standby loss tests, and requested clarification on DOE's proposal, stating that the language in the NOPR preamble and the proposed appendix A in the NOPR regulatory text were not consistent. (Bradford White, No. 21 at p. 8)

DOE agrees with A.O. Smith that, for an outlet temperature requirement, as opposed to a mean tank temperature requirement, setting the tank thermostat for the thermal efficiency test is irrelevant as long as the water heater is firing continuously at full firing rate and all the specifications required for the steady-state verification period, including the outlet water temperature requirement, are met. However, because the thermostat setting does not affect the operation of the water heater during the thermal efficiency test as long as the burner is firing continuously at full firing rate, the thermostat setting used in the thermal efficiency test does not necessarily provide an outlet water temperature of 140 °F ± 5 °F when water is not flowing through the water heater. In order to ensure that this outlet water temperature requirement is met, DOE believes that the thermostat setting needs to be set such that the maximum outlet water temperature after cut-out is 140 °F ± 5 °F before beginning the standby loss test.

While the thermostat settings used during the thermal efficiency test do not affect the test results so long as the burner fires continuously at full firing rate, DOE understands that the standby loss test is often performed directly after the thermal efficiency test. In this final rule, DOE is adopting provisions such that a soak-in period is not required in between the thermal efficiency and standby loss tests, if no settings on the water heaters are changed and the water heater is not turned off. However, setting the tank thermostat between the thermal efficiency and standby loss tests would inherently require changing settings on the water heater, unless the thermostat was already set to achieve the required outlet water temperature after cut-out of 140 °F ± 5 °F. Therefore, DOE believes that the tank thermostat must be set to meet the outlet water temperature requirement before the thermal efficiency test. DOE notes that requiring the tank thermostat to be set prior to the thermal efficiency test is consistent with DOE's current test procedure, DOE's proposal in the May 2016 NOPR, and with AHRI's comment.

DOE agrees with AHRI and A.O. Smith that it would be difficult to set the tank thermostat without water flowing through the water heater such that the outlet water temperature after cut-out is 140 °F ± 5 °F, as measured downstream of a heat trap in the outlet water piping. Additionally, DOE believes that the tank thermostat must be set without water flowing through the water heater; otherwise, both the tank thermostat and water flow rate would affect the measured outlet water temperature, and the thermostat settings obtained might not ensure that the outlet water temperature requirement is met without water flowing. Therefore, DOE believes that the thermostat should be set based on the reading of a temperature sensor located inside the tank. However, commenters disagreed on the location of measurement, with AHRI suggesting using the temperature recorded at the topmost temperature sensor in the tank that is used for measurement of mean tank temperature, while A.O. Smith suggested the placement of a temperature sensor inside the tank within 1 inch of the water heater outlet. While a temperature sensor within one inch of the water heater outlet is closer to the temperature of the water delivered than is the topmost temperature sensor used for mean tank temperature calculation, the difference between these temperatures is likely insignificant, and therefore, the placement of an additional temperature sensor in the tank for the sole purpose of setting the tank thermostat would be an unnecessary burden to manufacturers. Consequently, DOE is adopting a requirement that the tank thermostat be set using the reading from the topmost tank temperature sensor used to calculate mean tank temperature. Based on the above, DOE concludes that there is evidence that setting the thermostat according to the mean tank temperature, as is done in

ANSI Z21.10.3-2015, does not provide an accurate reflection of the energy efficiency during a representative average use cycle for certain equipment. DOE further concludes that the method for setting the thermostat adopted in this final rule provides an accurate reflection of energy efficiency for all kinds of gas-fired and oil-fired storage water heaters on the market. Therefore, DOE concludes that the method adopted in this final rule is consistent with the industry standard, ANSI Z21.10.3-2015, but provides flexibility so that all designs of gas-fired and oil-fired storage water heaters can achieve the temperature requirement used for setting the tank thermostat. DOE also concludes that the method adopted in this final rule is not unduly burdensome to conduct. Therefore, the changes adopted are better aligned with the requirements of 42 U.S.C. 6314(a)(2).

In response to Rheem, while DOE proposed to use outlet water temperature for the purpose of setting the tank thermostat for the standby loss test, DOE still proposed to use mean tank temperature for determining heat loss during the standby loss test. 81 FR 28588, 28604 (May 9, 2016). In this final rule, DOE is adopting provisions for determining heat loss during the standby loss test using mean tank temperature, similar to those included in annex E.2 of ANSI Z21.10.3-2015.

For gas-fired and oil-fired storage water heaters and storage-type instantaneous water heaters, DOE is adopting a requirement that the tank thermostat be set prior to the steady-state verification period. The thermostat must be set starting with the tank full of water at the water supply temperature. The thermostat must be set such that the maximum water temperature measured at the topmost tank temperature sensor after cut-out (and while water is not flowing through the water heater) is 140 °F ± 5 °F. The thermostat also must be set such that with water flowing through the unit continuously, the outlet water temperature can be maintained at 70 °F ± 2 °F above the supply water temperature, as required during the thermal efficiency test. DOE's updated requirements for determining steady-state operation for the thermal efficiency test and the steady-state verification period are discussed in section III.F.1 of this final rule. If conducting a standby loss test after a thermal efficiency test, the thermostat setting established prior to the thermal efficiency test would be used for the standby loss test, and no separate procedure would be needed for setting the thermostat. However, if the standby loss test is run without a previously run thermal efficiency test, the thermostat would need to be set using the same procedure as required before the thermal efficiency test, such that the maximum top tank sensor water temperature after cut-out is 140 °F ± 5 °F. In this case, the tank thermostat must be set prior to the soak-in period.

2. Electric Storage Water Heaters

DOE proposed to maintain the mean tank temperature requirement for the standby loss test for electric storage water heaters, rather than adopt an outlet water temperature requirement, because of complications involved with setting multiple tank thermostats. 81 FR 28588, 28604 (May 9, 2016). Electric storage water heaters typically have multiple heating elements and thermostats, and each thermostat needs to be set prior to beginning the standby loss test. Therefore, DOE tentatively determined that electric storage water heaters are not well-suited to an outlet water temperature requirement because it is unclear how the lower thermostat(s) would be set to achieve a designated outlet water temperature. However, DOE proposed to clarify its language specifying the method for setting thermostats in an electric storage water heater with multiple thermostats. Specifically, DOE proposed to clarify that the thermostats are to be set in immediate succession, starting from the topmost thermostat. DOE also proposed to clarify that when setting each thermostat, the mean tank temperature is calculated using only temperature readings measured at locations higher in the tank than the heating element corresponding to the thermostat being set, with the exception of the bottommost thermostat. Finally, DOE proposed to clarify that all thermostats below the thermostat being tested must be turned off so that no elements below the thermostat being tested are in operation.

Several commenters agreed with DOE's proposal to maintain the existing mean tank temperature requirement for setting the tank thermostat for electric storage water heaters. (Bradford White, No. 21 at p. 8; AHRI, No. 26 at p. 13; A.O. Smith, No. 27 at p. 5; Joint Advocates, No. 32 at p. 2; Rheem, No. 34 at p. 9) A.O. Smith also agreed with DOE's proposed clarification regarding how to set thermostats for electric storage water heaters with multiple thermostats. (A.O. Smith, No. 27 at p. 5) However, AHRI, Rheem, and Bradford White disagreed with DOE's proposal on how to set thermostats for units with multiple thermostats. Specifically, AHRI and Rheem suggested that only the topmost and bottommost thermostats be set and used for the standby loss test. (AHRI, No. 26 at p. 10; Rheem, No. 24 at p. 9) AHRI stated that DOE's proposal is unnecessarily burdensome and complicated, and that it does not matter how many thermostats and associated heating elements are used to meet the mean tank temperature requirement for the standby loss test. (AHRI, No. 26 at p. 10) Rheem stated that using just the topmost and bottommost thermostats would simplify the test and improve consistency among units with different thermostat-to-element ratios. Additionally, Rheem commented that not all laboratories can supply power greater than 36 kW. (Rheem, No. 24 at p. 9) Bradford White recommended that the lowest thermostat be set first, and then the next highest, etc. Bradford White also did not support DOE's proposal to calculate mean tank temperature with only temperature readings measured higher than the heating element corresponding to the thermostat being set, with the exception of the bottom thermostat. (Bradford White, No. 21 at p. 8)

After review of stakeholder comments and consultation with several independent testing laboratories, DOE agrees with AHRI and Rheem that setting all thermostats for the standby loss test for commercial electric storage water heaters with multiple thermostats is unnecessary. DOE agrees with AHRI that setting fewer thermostats would reduce burden to manufacturers and would be unlikely to affect the results of the standby loss test, because it is unlikely that more than one heating element will experience a call for heat during the standby loss test. DOE also notes, based on its assessment of commercial electric storage water heaters on the market, most models have banks of heating elements grouped together such that a call for heat in the lowest thermostat will likely heat the water up to temperature at the nearby thermostats as well. Additionally, DOE agrees with Rheem that limiting the number of thermostats (and correspondingly the number of heating elements) used during the standby loss test may simplify the testing of higher input capacity units by limiting the total amperage draw to a level that most laboratories would be able to provide.

DOE believes that the topmost thermostat should be set using mean tank temperature calculated only with temperature readings measured at locations higher in the tank than the heating element corresponding to the thermostat being set. If the water lower in the tank is included in the mean tank temperature calculation and has not been previously heated by a lower element, as suggested by Bradford

White, the heating element(s) corresponding to the topmost thermostat would have to heat water at the top of the tank to a temperature much higher than the required mean tank temperature in order to achieve the mean tank temperature requirement.

In this final rule, DOE is maintaining a mean tank temperature requirement for the standby loss test for electric storage water heaters. DOE is adopting its proposed requirement that that the tank thermostat(s) be set prior to conducting the required soak-in period. DOE is also clarifying that the thermostat(s) for electric storage water heaters must be set while no water is flowing through the unit. DOE is also adopting requirements for setting tank thermostats for electric storage water heaters with multiple thermostats. Specifically, DOE is specifying that only the topmost and bottommost thermostats be set, and that all other thermostats and corresponding elements not operate while setting thermostats or during conduct of the standby loss test. DOE also specifies that when setting the topmost thermostat, only temperature readings measured at locations higher in the tank than the heating element corresponding to the topmost thermostat (the lowest heating element corresponding to the thermostat if the thermostat controls more than one element) should be used to calculate mean tank temperature. However, when setting the bottommost thermostat, DOE specifies that all temperature readings should be used to calculate mean tank temperature. These changes are consistent with the industry test method, ANSI Z21.10.3-2015, and simply provide additional detail regarding the method for setting the thermostat to improve consistency and repeatability.

F. Steady-State Requirements and Soak-In Period

1. Steady-State Verification

In the May 2016 NOPR, DOE noted that the required three-minute period for verifying steady-state operation prior to the thermal efficiency test, which is included in Exhibit G.1 of ANSI Z21.10.3-2011 (currently incorporated by reference in DOE's test procedure), may not be sufficiently long. 81 FR 28588, 28601 (May 9, 2016). Additionally, DOE noted that the current test procedure does not impose requirements for maximum variation in inlet water temperature or water flow rate during this period for verifying steady-state operation. Therefore, DOE requested information and data that might support a change to the provisions for establishing steady-state operation in its test procedure.

In response to the May 2016 NOPR, Bradford White stated that it is possible to meet the current criterion of no variation in outlet water temperature in excess of 2 °F over a 3-minute period before the water heater has reached steady-state conditions. (Bradford White, No. 19 at p. 4) Bradford White and AHRI both commented that verification of steady-state operation is an area in which the repeatability of the thermal efficiency test can be improved. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at p. 9) Bradford White and AHRI also suggested that DOE adopt more stringent requirements for establishing steady-state operation prior to the thermal efficiency test, and included specific guidelines in their comments that they recommend DOE implement. Specifically, Bradford White and AHRI suggested establishing an hour-long period during which the requirements of DOE's current thermal efficiency test procedure would have to be met, along with additional requirements for maximum variation in: (1) Water flow rate (± 0.25 gallons per minute (gpm)); (2) gas higher heating value (± 5 percent, measured every 30 minutes); (3) inlet water temperature (± 0.50 °F, with respect to the initial reading); and (4) the difference between initial and final rise between inlet and outlet water temperatures (± 0.50 °F and ± 1 °F for units with input rates <500,000 Btu/h and ≥500,000 Btu/h, respectively). Bradford White and AHRI further suggested that the final 30 minutes of the hour-long period would be used to calculate the results of the thermal efficiency test. (Bradford White, No. 19 at p. 5; AHRI, No. 26 at pp. 9-10) AHRI also suggested that these measurements would be required at least every 60 seconds, except for gas higher heating value.

A.O. Smith commented that while an additional requirement for establishing steady-state operation could improve repeatability, it would be a new requirement that manufacturers would need to further analyze. (A.O. Smith, No. 27 at p. 3) However, A.O. Smith suggested revised guidelines for determining steady-state operation in case DOE proceeds with such modifications to its test procedure. Specifically, A.O. Smith suggested that steady-state be considered established once 30 minutes of consecutive readings confirm that: (1) Inlet water temperature is maintained at 70 °F ± 2 °F, (2) outlet water temperature is maintained at 70 °F ± 2 °F above supply water temperature, and (3) fuel input rate is within 2 percent of the rated input. A. O. Smith argued that the required measurement intervals should be one minute for storage-type water heaters but only 15 minutes for instantaneous water heaters because instantaneous water heaters do not experience a lasting effect from momentary variations in water temperature as do storage-type water heaters. (A.O. Smith, No. 27 at pp. 3-4)

Rheem commented that it typically monitors the outlet water temperature of storage-type water heaters for at least 20 minutes prior to testing but does not record this data. Rheem also stated that it typically runs three thermal efficiency tests after steady-state conditions are established prior to beginning the thermal efficiency test for which data are recorded. Additionally, Rheem asserted that instantaneous water heaters only require 5 minutes of operation before steady-state conditions are reached, and that different steady-state verification requirements may be warranted for different classes of CWH equipment. (Rheem, No. 34 at p. 7)

DOE agrees with the commenters that the guidelines for establishing steady-state operation that were suggested by Bradford White and AHRI would improve test repeatability. Specifically, DOE agrees with these commenters that extending the duration of the steady-state verification period from 3 minutes to 30 minutes prior to the start of the 30 minute period for the thermal efficiency test (for which steady-state conditions must also be maintained, equating to a total of one hour of continuous steady-state operation), and adding additional requirements for verification would improve the repeatability of the test. DOE notes these guidelines were suggested by a trade organization that represents manufacturers that produce over 90 percent of CWH equipment sold in the United States, indicating that the need for adopting these guidelines is widely understood across the industry. Additionally, Bradford White noted that its suggested guidelines for determining steady-state operation were developed by an industry working group, and that AHRI plans to adopt these test guidelines. (Bradford White, No. 21 at p. 5) Therefore, DOE concludes that the modifications to DOE's steady-state verification procedures adopted in this final rule do not require further analysis and comment from manufacturers, as suggested by A.O. Smith, because DOE's adopted requirements contain only minor deviations from the guidelines suggested by Bradford White and AHRI. However, DOE is open to stakeholder feedback regarding these procedural modifications related to establishment of steady-state operation, including

experiences prior to the compliance date, and the Department would consider addressing any potential issues in a future test procedure rulemaking or guidance, as necessary.

DOE agrees with all of the conditions specified in the steady-state requirements recommended by Bradford White and AHRI, except for the requirement that there be no variation in the higher heating value of greater than ± 5 percent. DOE notes that AHRI and Bradford White recommended requirements for steady-state verification that include a maximum variation on the fuel higher heating value, while the guidelines suggested by A.O. Smith instead include a requirement that the fuel input rate be maintained within 2 percent of the rated input. While DOE recognizes that restricting variation in fuel higher heating value ensures consistency in the composition of fuel consumed (

e.g.,

ensuring steady-state operation in the case that the fuel source is changed during the test), DOE believes that restricting variation on fuel input rate would be more effective in terms of ensuring that steady-state operation is reached. Variation in fuel higher heating value is reflected in measurement of fuel input rate, along with variation in gas consumption. Additionally, section 2.3.3 of ANSI Z21.10.3-2011, which is referenced in exhibit G.1 of ANSI Z21.10.3-2011 (referenced in DOE's current test procedure), specifies that the burner shall be adjusted to achieve a measured input within ± 2 percent of the manufacturer's rated input 15 minutes after being placed in operation from a room temperature start. Therefore, DOE believes that including a similar requirement for restricting variation in fuel input rate when verifying steady-state operation is consistent with DOE's current test procedure and the industry consensus test standard (ANSI Z21.10.3).

DOE does not expect a requirement to measure fuel input rate during the steady-state verification period and thermal efficiency test to impose any significant burden to manufacturers. As discussed in section III.F.2 of this final rule, no commenters suggested that DOE's proposed clarification that full firing rate must be maintained throughout the thermal efficiency test would be burdensome or difficult to achieve. Determination of fuel input rate for each 10-minute interval simply requires recording the fuel consumption every ten minutes.

Consequently, DOE is adopting the requirements for determining that steady-state operation has been achieved, as recommended by AHRI and Bradford White with one modification. Specifically, DOE is declining AHRI and Bradford White's suggestion of a requirement for maintaining the fuel higher heating value within ± 5 percent in favor of adopting A.O. Smith's suggestion of a requirement to maintain the fuel input rate within ± 2 percent. Under the test procedure adopted in this final rule, the thermal efficiency test will be complete when there is a continuous, one-hour-long period (comprising the 30-minute “steady-state verification period” and 30-minute “thermal efficiency test”) meeting the following requirements: (1) Outlet water temperature is maintained at 70 °F ± 2 °F above supply water temperature, (2) water flow variation is no greater than ± 0.25 gpm from the initial value, (3) fuel input rate is maintained within 2 percent of the rated input certified by the manufacturer, (4) the supply water temperature (or inlet water temperature if a recirculating loop is used for instantaneous water heaters and hot water supply boilers) is within ± 0.5 °F of its initial reading, and (5) the rise between the supply water temperature (or inlet water temperature if a recirculating loop is used for instantaneous water heaters and hot water supply boilers) and outlet water temperatures is within ± 0.50 °F of its initial value for the duration of the one-hour-long period for units with rated input less than 500,000 Btu/h, and within ± 1 °F of its initial value for units with rated input greater than or equal to 500,000 Btu/h. The final 30 minutes will be used to calculate thermal efficiency. DOE concludes that the method for determining steady-state operation adopted in this final rule is consistent with the industry test standard, ANSI Z21.10.3-2015, but provides more stringent requirements to improve consistency. Based on the comments received from stakeholders and the foregoing discussion, DOE concludes that the adopted method will produce results which better reflect the energy efficiency of CWH equipment during a representative average use cycle and will not be unduly burdensome to conduct, as required by EPCA. (42 U.S.C. 6314(a)(2))

In response to A.O. Smith's suggestion that DOE increase the measurement interval for instantaneous type water heaters, DOE disagrees and is maintaining 1-minute measurement intervals for the thermal efficiency test as currently included in DOE's test procedure. This interval applies to the new requirements for determining steady-state operation (adopted from the guidelines suggested by Bradford White and AHRI), except for fuel input rate, which has a 10-minute measurement interval. While DOE acknowledges it is possible that burner fluctuations may not have as much of a lasting effect on instantaneous water heaters (other than storage-type instantaneous water heaters) as suggested by A.O. Smith, DOE is not adopting a longer measurement interval for instantaneous water heaters than for storage water heaters. DOE believes that the 1-minute measurement interval included in DOE's current test procedure is appropriate for both storage water heaters and instantaneous water heaters, and that it is appropriate and not significantly burdensome to manufacturers to extend this measurement interval to the measurements taken during the steady-state verification period prior to the thermal efficiency test. DOE notes that this one-minute interval was included in the suggestion for determining steady-state operation from both Bradford White and AHRI. Measurement intervals for both the thermal efficiency and standby loss tests are further discussed in section III.B.5 of this final rule.

DOE disagrees with Rheem's suggestion that separate requirements may be warranted for verifying steady-state operation for instantaneous water heaters and storage water heaters, and is adopting the same requirements for both kinds of CWH equipment. Many storage water heaters, particularly those with a low input-volume ratio, may require a significant amount of time before steady-state conditions are reached and measurements can begin constituting the steady-state verification period. In contrast, instantaneous water heaters, with a much higher input-volume ratio, may reach steady-state conditions very quickly, and it may only take a short time after beginning water heater operation before measurements can be included in the steady-state verification period. However, DOE is not adopting any provisions or requirements regarding the duration of the period during which CWH equipment warms up to reach steady-state conditions. Nonetheless, DOE continues to believe that a 30-minute period for verifying steady-state operation is appropriate for both storage water heaters and instantaneous water heaters, and that the duration of this period should not depend upon the time it takes for the water heater to warm up. Thus, DOE is not adopting different verification requirements for instantaneous water heaters, as suggested by Rheem.

2. Clarifying Statements

In the May 2016 NOPR, DOE proposed adding clarifying statements to its test procedure regarding steady-state operation. Specifically, DOE proposed to require that the test entity must maintain the outlet water temperature at 70 °F ± 2 °F above the supply water temperature and ensure the burner fires continuously at the full firing rate (

i.e.,

no modulation or cut-outs) for the entire duration of the thermal efficiency test. Further, DOE proposed to clarify that once steady-state operation is achieved, as determined by no variation of the outlet water temperature in excess of 2 °F over a 3-minute period, no settings on the water heating equipment may be changed until measurements for the thermal efficiency test are finished. DOE also proposed a similar clarification for the standby loss test for CWH equipment other than flow-activated instantaneous water heaters, requiring that after the first cut-out before beginning the standby loss test, no settings may be changed on the water heater until measurements for the standby loss test are finished. 81 FR 28588, 28604-28605 (May 9, 2016).

In response to the May 2016 NOPR, several commenters agreed with DOE's proposed clarifications. (Bock, No. 19 at p. 2; Bradford White, No. 21 at p. 8, A.O. Smith, No. 27 at p. 6; Rheem, No. 34 at p. 9) Bradford White further noted that it believes that the content of DOE's clarifying statements are already understood and common industry practice. However, Bradford White noted that it did not agree with the 3-minute period for determining steady-state operation. (Bradford White, No. 21 at p. 8)

The provisions for establishing steady-state operation prior to the thermal efficiency test that DOE is adopting in this final rule (as discussed in section III.F.1 of this final rule) include, among other requirements, that the following conditions be maintained throughout the test: (1) The specified outlet water temperature, and (2) the fuel input rate within ± 2 percent of the manufacturer's rated input. This is in contrast to the existing requirement that there be no variation in outlet water temperature in excess of 2 °F over a 3-minute period prior to beginning the test. Therefore, additional clarifying statements addressing these conditions during the thermal efficiency test are no longer necessary, as they now must be maintained throughout the duration of the test. However, DOE is adopting its proposed provisions requiring that no settings may be changed on the CWH equipment being tested: (1) Once the steady-state conditions are established during the steady-state verification test and until the thermal efficiency test is completed; and (2) after the first cut-out before beginning the standby loss test until the measurements of the standby loss test are completed (for all CWH equipment, except for flow-activated instantaneous water heaters and externally thermostatically-activated instantaneous water heaters). (For more information on the standby loss test procedure adopted for flow-activated and externally thermostatically-activated instantaneous water heaters, see section III.H.3 of this final rule.) As noted above by commenters, these requirements to leave the settings on CWH equipment unchanged during certain portions of testing are already generally understood and common industry practice. DOE is adding these requirements to clarify the industry test method, and, therefore, concludes that these changes are consistent with ANSI Z21.10.3-2015.

3. Soak-In Period

DOE's current thermal efficiency test procedure for gas-fired and oil-fired CWH equipment, which incorporates by reference Exhibit G.1 of ANSI Z21.10.3-2011, requires the water heater to achieve steady-state conditions prior to beginning measurements for the thermal efficiency test. Specifically, the test procedure requires the outlet water temperature to be maintained at 70 °F ± 2 °F above the supply water temperature, with no variation in excess of 2 °F over a 3-minute period. DOE's current standby loss test procedure for gas-fired and oil-fired CWH equipment, which incorporates by reference Exhibit G.2 of ANSI Z21.10.3-2011, requires the water heater to reach a mean tank temperature of 140 °F and remain in standby mode after the first cut-out until the next cut-out before measurements for the standby loss test begin. However, as discussed in the May 2016 NOPR, DOE thought it possible that these provisions for both tests might be insufficient for ensuring that the tank insulation is fully heated before beginning test measurements.

In the May 2016 NOPR, DOE proposed to require a soak-in period prior to beginning the thermal efficiency and standby loss tests, in which the water heater would remain idle (

i.e.,

no water draws) for at least 12 hours with thermostat(s) maintained at settings that would achieve the required water temperature. 81 FR 28588, 28598 (May 9, 2016). However, DOE proposed not requiring a soak-in period prior to the beginning of an efficiency test (

i.e.,

thermal efficiency or standby loss) if no settings on the water heater were changed and the water heater had not been turned off since the end of a previously run efficiency test.

In response to the May 2016 NOPR, A.O. Smith stated that all proposed requirements for soak-in periods are unnecessary and would not improve test accuracy or repeatability, given the requirements for establishing steady-state operation. (A.O. Smith, No. 27 at p. 17) Several commenters stated that a soak-in period is unnecessary before a thermal efficiency test because DOE's test procedure requires that steady-state operation be reached prior to beginning measurements. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10; Raypak, No. 28 at p. 6; Rheem, No. 34 at p. 6) However, Bradford White, AHRI, and Raypak indicated that the soak-in period would be useful prior to a thermal efficiency test if the water heater were not stored in a conditioned space (

i.e.,

maintained at 75 °F ± 10 °F according to Bradford White, maintained at temperature above freezing according to Raypak, and unspecified according to AHRI). (Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10; Raypak, No. 28 at p. 6) Bradford White and AHRI also argued that a soak-in period should only be required before a standby loss test if the test is not begun within 3 hours of the end of a thermal efficiency test. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at pp. 9-10) Raypak indicated that a soak-in period should only be required before a standby loss test if the water heater is not stored in a conditioned space. (Raypak, No. 28 at p. 6) Rheem stated that a soak-in period of 12 hours is sufficiently long before conducting a standby loss test without a previously run thermal efficiency test. (Rheem, No. 34 at p. 6)

A.O. Smith argued that while not requiring human interaction, a soak-in period would be burdensome to

manufacturers because it would require lab space to be occupied and certain environmental conditions to be monitored and maintained. (A.O. Smith, No. 27 at p. 17) Rheem stated that the soak-in period would place an additional burden on manufacturers in terms of time, resources, and laboratory space, if required when a thermal efficiency test is performed in conjunction with a standby loss test. (Rheem, No. 34 at p. 6)

DOE acknowledges that a soak-in period would not be warranted before a thermal efficiency test if steady-state operation is assured prior to beginning the test. Given the more stringent provisions for determining steady-state operation that DOE is adopting in this final rule (discussed in section III.F.1), DOE agrees with commenters that a soak-in period is not needed before the thermal efficiency test, and is not adopting this requirement. While several commenters indicated that a soak-in period might be helpful if the water heater were not stored in a conditioned space, DOE believes that in this case, the water heater would simply take longer to reach the required steady-state conditions before beginning the thermal efficiency test, and that an additional soak-in period would not be necessary.

DOE believes that a soak-in period would improve test repeatability for the standby loss test if a thermal efficiency test were not previously conducted. In the May 2016 NOPR, DOE also proposed that a soak-in period be required if any settings on the water heater had been changed, or if the water heater had been turned off since the end of a previously run efficiency test. 81 FR 28588, 28598 (May 9, 2016). However, Bradford White and AHRI indicated that a soak-in period should only be required before the standby loss test if the standby loss test does not begin within three hours of the end of a previously run thermal efficiency test. (Bradford White, No. 19 at p. 4; AHRI, No. 26 at p. 9)

DOE disagrees with the suggestion that a soak-in period would not be necessary if a water heater were turned off after a thermal efficiency test but for three hours or less before beginning the standby loss test. DOE believes that the water heater should be turned on at all times between the end of the thermal efficiency test and the beginning of the standby loss test to ensure that the thermal equilibrium within the tank insulation, or “soaking in,” achieved during the thermal efficiency test is not lost before starting the standby loss test. DOE notes that water heaters likely vary significantly in the time required after ending the thermal efficiency test before the burner cuts in again. This variation includes factors such as storage volume, tank heat losses, and thermostat control algorithms. For certain water heaters, this time may even exceed three hours, in which case it would not matter if the water heater were turned on or off during this period. However, in other cases, the thermal equilibrium of the tank may be lost if the water heater is turned off between tests. A decrease in the insulation temperature between tests might require additional energy consumption to reheat the insulation during the standby loss test, which would result in higher calculated values of standby loss.

DOE also believes that a soak-in period requirement will improve the repeatability of the standby loss test for electric storage water heaters. Electric storage water heaters do not have a thermal efficiency test, so unless multiple standby loss tests are run consecutively, the soak-in period will ensure that the tank insulation has reached thermal equilibrium before measurements for the standby loss test begin. Therefore, to improve repeatability of the standby loss test for storage water heaters and storage-type instantaneous water heaters, DOE is adopting a requirement that a soak-in period of 12 hours be conducted before the standby loss test unless no settings on the water heater have been changed and the water heater has not been turned off since the end of a previously run efficiency test. DOE concludes that adding requirements for the soak-in period (when required) will improve the repeatability of the test result, but is consistent with ANSI Z21.10.3-2015.

The provisions DOE is adopting that specify when a 12-hour soak-in period is required prior to the standby loss test (

i.e.,

required unless no settings on the water heater have been changed and the water heater has not been turned off since the end of a previously run efficiency test) allow flexibility for the manufacturer or testing agency. After completion of the thermal efficiency test, as long as the water heater stays turned on and no settings are changed, the laboratory technician may choose to begin the standby loss test immediately, or allow the tank to soak in longer before beginning the standby loss test.

G. Definitions for Certain Consumer Water Heaters and Commercial Water Heating Equipment

1. Consumer Water Heaters

A statutory definition for consumer “water heater” was added to EPCA by the National Appliance Energy Conservation Act of 1987 (NAECA; Pub. L. 100-12, March 17, 1987), which specifies input ratings at or below which water heaters are to be classified as consumer water heaters (

e.g.,

75,000 Btu/h for gas-fired storage water heaters; 12 kW for electric storage water heaters and electric instantaneous water heaters; 210,000 Btu/h for oil-fired instantaneous water heaters). (42 U.S.C. 6291(27)) NAECA also established standards for gas-fired consumer water heaters, oil-fired consumer water heaters, and electric consumer water heaters. (42 U.S.C. 6295(e)(1))

DOE restated the statutory definition of “water heater” in the appliance standards regulations applicable to consumer products at 10 CFR 430.2. In addition to adopting EPCA's definition of “water heater” for standards applicable to consumer products, DOE defined a variety of terms in the test procedure provisions applicable to consumer water heaters to help specify the test procedure provisions applicable to specific kinds of water heaters (

e.g.,

“gas instantaneous water heater” and “electric storage water heater”). 55 FR 42162, 42169 (October 17, 1990). These test procedure definitions included provisions related to water temperature design characteristics and rated storage volume. The standards at 10 CFR 430.32 and the “water heater” definition at 10 CFR 430.2 did not include any such limitations.

In an effort to consolidate all relevant definitions in 10 CFR 430.2, DOE removed the definitions for specific kinds of consumer water heaters from its test method at appendix E to subpart B of part 430 (

i.e.,

“electric heat pump water heater,” “electric storage water heater,” “gas-fired instantaneous water heater,” “gas-fired storage water heater,” and “oil-fired storage water heater”) and placed these definitions in the general definition section at 10 CFR 430.2, along with newly established definitions for “gas-fired heat pump water heaters,” “oil-fired instantaneous water heater,” and “electric instantaneous water heater.” 79 FR 40542, 40549, 40566-40567 (July 11, 2014). The reorganization of the existing definitions and the newly established definitions became effective on July 13, 2015, and these definitions excluded products with a rated storage capacity greater than 120 gallons and, in some cases, excluded products designed to heat and store water at a thermostatically controlled temperature greater than 180 °F. 79 FR 40542, 40566-40567 (July 11, 2014).

As noted previously, the standards and definition set forth in EPCA do not include any limitation related to the water temperature or storage capacity.

Therefore, prior to the effective date of the amendments in the July 2014 final rule, any product meeting the definition of a “water heater” as established under EPCA and restated in 10 CFR 430.2 would have been subject to the statutory standards applicable to consumer water heaters (

i.e.,

water heaters within the input limits established under EPCA would have been subject to the standards regardless of the water delivery temperature or storage capacity).

In the May 2016 NOPR, DOE proposed to amend the definitions for specific types of consumer water heaters included at 10 CFR 430.2 by removing from the definitions the specifications related to the water temperature and storage capacity. 81 FR 28588, 28605-28606 (May 9, 2016). Because a model that would otherwise meet the definition of a consumer water heater could not “become” commercial as the result of the unit's capability of producing water at temperatures above 180 °F or by having a rated capacity in excess of 120 gallons, the proposed definitions better reflect the statutory definitions and DOE's statutory authority. More generally, DOE clarified that a product that utilizes gas, oil, or electricity to heat potable water for use outside the heater upon demand that does not meet the statutory definition of “water heater” at 42 U.S.C. 6291(27) would be a commercial water heater, subject to the standards for such water heaters as set forth in 42 U.S.C. 6313(a)(5).

DOE received comments on the proposed removal of the temperature and the capacity criteria. A number of stakeholders disagreed with DOE's proposal to remove the 180 °F water delivery temperature from the consumer water heater definitions at 430.2. (HTP, No. 24 at p. 2; AHRI, No. 26 at pp. 4-5; Rinnai, No. 31 at p. 2; Bock, No. 19 at p. 2; Bradford White, No. 21 at pp. 8-9; Rheem, No. 34 at pp. 10-11) AHRI argued that by removing these criteria, specifically the 180 °F exclusion, from its consumer water heater definitions, DOE would be reversing a long-standing position that AHRI stated was determined valid in the July 2014 final rule. AHRI also stated that DOE did not provide sufficient explanation for reversing its long-standing position. (AHRI, No. 26 at pp. 4-5)

Contrary to AHRI's understanding, the relocation of definitions from the test procedure provisions to the general definitions section in the July 2014 final rule was not for the purpose of validating a long-standing position. As noted previously, “water heater” is defined by EPCA, and remains defined in 10 CFR 430.2, without restriction as to water temperature delivery or storage capacity. The addition of these exclusions to DOE's definitions at 10 CFR 430.2 was not intended to limit the applicability of the definition of “water heater.” As explained in the July 2014 final rule, definitions of “gas-fired heat pump water heater,” “oil-fired instantaneous water heater,” and “electric instantaneous water heater” were added in the context of the new test procedure. 79 FR 40542, 40549 (July 11, 2014). The notice also stated that all other definitions from the test procedure were being relocated.

Id.

The July 2014 final rule did not discuss restricting the statutory or regulatory definition of “water heater.” As opposed to validating a long-standing position, DOE recognizes that by relocating the definitions it furthered confusion regarding the applicability of the standards. As previously stated, prior to the effective date of the July 2014 final rule, any product meeting the definition of a “water heater” would have been subject to the statutory standards applicable to consumer water heaters, regardless of the water delivery temperature or storage capacity. The temperature and capacity restrictions were for the purpose of applying provisions of the test procedure, not the standard. Therefore, DOE considers removal of these exclusions as a correction to a recent change, and not as a reversal of a long-standing position. Additionally, as discussed in the following paragraphs, DOE has concluded use of such limitations would be inappropriate given, in part, the water heaters currently available on the market.

AHRI further argued that when interpreting the statutory definition applicable to consumer water heaters, DOE must first consider the definition of “consumer product.” When determining whether a product falls within the definition of “water heater” in the context of the consumer product standards, AHRI argued that DOE must first consider whether that product is a consumer product and that the temperature and capacity criteria inform that consideration. AHRI pointed to prior consideration by DOE of factors beyond those in the EPCA definition to distinguish between consumer and commercial products, citing the April 2010 final rule (75 FR 20112, 20127), in which DOE stated that pool heaters marketed as commercial equipment and that contain additional design modifications related to safety requirements for installation in commercial buildings would not be covered by DOE's consumer product standard for pool heaters. (AHRI, No. 26 at pp. 5-6) In the present case, AHRI essentially argued that water heaters that are designed to deliver water at temperatures greater than 180 °F or that have a rated volume in excess of 120 gallons are not to any significant extent marketed or sold for personal use by individuals, and therefore cannot be consumer products. Other commenters asserted that water delivery temperature provides a meaningful way to distinguish between consumer and commercial water heaters. (Bock, No. 19 at p. 2; Bradford White, No. 21 at p. 9; Rinnai, No. 31 at p. 2) HTP and AHRI stated that units that heat water above 180 °F are only used in commercial applications, and that water heated above 180 °F in a residential application presents a scald hazard. (HTP, No. 24 at p. 2; AHRI, No. 26 at p. 4) Bradford White stated that all of its commercial electric storage basic models would be mistakenly reclassified if DOE removed the 180 °F exclusion from its consumer water heater definitions, even though according to Bradford White, these models are not appropriate for residential applications. (Bradford White, No. 21 at p. 9) A.O. Smith stated that defining as consumer water heaters gas instantaneous water heaters with an input capacity less than or equal to 200,000 Btu/h and a water delivery temperature greater than 180 °F would make ratings inconsistent with other commercial water heaters. (A.O. Smith, No. 27 at p. 10)

Several manufacturers also disagreed with the removal of the storage capacity criterion. (Bradford White, No. 21 at p. 9; A.O. Smith, No. 27 at p. 6; Rheem, No. 34 at p. 11) Bradford White and A.O. Smith stated that models with storage volume greater than 120 gallons require American Society of Mechanical Engineers (ASME) pressure vessel certification in most jurisdictions and that these models would not be used in residential applications. Bradford White also commented that the cost of ASME certification is high enough to be cost-prohibitive for residential applications. (Bradford White, No. 21 at p. 9)

DOE reiterates that the relocation of definitions relevant to the test procedure to the general definition section at 10 CFR 430.2 was not intended to reflect a prior interpretation restricting the applicability of the standards for consumer water heaters. However, even if the removal of the water temperature delivery and volume capacity limitations were a change to a long standing practice of distinguishing between consumer and commercial water heaters, a recent survey of the

market leads DOE to determine that such criteria would not be appropriate to distinguish between water heaters that are consumer products and those that are commercial products. While DOE acknowledges that water heaters with a water delivery temperature greater than 180 °F or with a storage volume greater than 120 gallons may not be commonly used in residential applications, the question is whether a water heater is of the type distributed in commerce to any significant extent for personal use by an individual. (42 U.S.C. 6291(1)) Consideration of whether an article is of a type distributed in commerce to any significant extent for personal use by an individual is made without regard to whether a specific article is in in fact distributed in such a manner.

Id.

In surveying the market, DOE has identified several water heaters that demonstrate that a reliance on a 180 °F threshold would be inappropriate for distinguishing between consumer and commercial water heaters. Rheem markets a water heater under its commercial line that has input ratings below the 12 kW threshold specified in the statutory definition for consumer water heaters and has thermostat controls that provide maximum water temperatures greater than 180 °F. (Docket No. EERE-2014-BT-TP-0008-0041) This water heater's installation instructions reference installation in the “home,” indicating that the model is distributed for consumer use. (Docket No. EERE-2014-BT-TP-0008-0040, pp. 15, 21) A water heater offered by A.O. Smith has two 4.5 kW heating elements arranged in a configuration typical for consumer water heaters and provides an input capacity below the statutory 12 kW threshold, but has a thermostat adjustable up to 181 °F, one degree above the 180 °F threshold in the regulatory definition of “electric storage water heater.” (Docket No. EERE-2014-BT-TP-0008-0038) The manual for the A.O. Smith product references installation in the home, again suggesting that the product is distributed, at least to an extent, for residential use. (Docket No. EERE-2014-BT-TP-0008-0037, pp. 8-9)

With regard to the 180 °F criterion, DOE's understanding is that exceeding the temperature threshold for a water heater can be achieved through replacement of a single part, the thermostat, which DOE believes can be very easily and inexpensively changed to allow for heating water to greater than 180 °F. As noted by A.O. Smith in its comment, the 180 °F operating limit is not necessarily a satisfactory criterion for separating consumer and commercial water heaters, because a thermostat designed to deliver water temperatures in excess of 180 °F can be installed at no additional cost on products that are consumer water heaters in all other respects. (A.O. Smith, No. 27 at pp. 6-7) A.O. Smith suggested that removing the 180 °F criterion for electric storage water heaters could dissuade manufacturers from trying to avoid DOE's standard for la

This text is long and has been trimmed here. Open the source document for the complete record.

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.