55FR23842

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Tuesday 

June 12, 1990 

Part Ill 

Department of 

Energy 

Office of Conservation and Renewable 

Energy 

10 CFR Part 435 

Energy Conservation Voluntary 

Performance Standards for New 

Commercial and Multi-Family High Rise 

Residential Buildings; Mandatory for New 

Federal Buildings; Final Rule, Response 

to Comments and Announcement of 

Appropriate Standby Loss Criteria 
 55FR23842

23842 Federal Register / Vol. 55, No. 113 / Tuesday, June 12, 1990 / Rules and Regulations 

DEPARTMENT OF ENERGY 

Office of Conservation and 

Renewable Energy 

10 CFR Part 435 

[Docket No. CAS-RM-79-112-C] 

Energy Conservation Voluntary 

Performance Standards for New 

Commercial and Multi-Family High Rise 

Residential Buildings; Mandatory for 

New Federal Buildings 

AGENCY: U.S. Department of Energy. 

ACTION: Final rule and response to 

comments and announcement of 

appropriate standby loss criteria. 

SUMMARY: Pursuant to the October 6, 

1989, Memorandum and Order of the 

United States District Court for the 

District of Columbia in Civil Action No. 

89-1315, Gas Appliance Manufacturers 

Association, Inc., et al., v. Secretary of 

Energy, the Department of Energy (DOE) 

hereby complies with the Memorandum 

and Order by publishing a Response to 

Comments and Announcement of 

Appropriate Standby Loss Criteria 

(Response and Announcement). The 

Court remanded 10 CFR 435.109, section 

9.3.2 and portions of Table 9.3-1 dealing 

with "Minimum Performance (Loss)" for 

electric, gas and oil storage water 

heaters pending reconsideration of those 

provisions on remand in a manner 

consistent with the Court's opinion. See 

Court's Memorandum and Order, dated 

October 6, 1989. In that regard, the Court 

directed as follows: (1) That DOE 

provide a statement of reasons for 

adoption of standby loss criteria, with 

attention to the relevant statutory 

requirements, including those dealing 

l111ith practicability, cost-benefit 

analysis, and impact on affected groups; 

(2) that DOE place in the public 

rulemaking record all the materials on 

which it now relies in determining the 

storage water heater criteria it adopts 

on remand; (3) that DOE publish its 

statement of reasons for adoption of 

standby loss criteria in the Federal 

Register; (4) that DOE make the 

materials upon which it relies available; 

(5) that DOE invite all interested 

participants to comment on the 

materials; (6) that plaintiffs and other 

interested persons file their response or 

responses with DOE; and (7) that DOE 

publish in the Federal Register a 

statement responding to plaintiffs' 

critique and any others, again with 

reference to the statutory requirements 

and announcing appropriate standby 

loss criteria. 

Pursuant to the Court's October 6, 

1989, Memorandum and Order, DOE has 

been enjoined from taking any action to 

enforce the requirements of section 9.3.2 

and the relevant portion of Table 9.3-1 

pending completion of the remand 

procedures described above. With 

today's publication of this Response and 

Announcement, that remand process is 

completed. In the following sections of 

this Response and Announcement, DOE 

reviews the circumstances surrounding 

the remand process, discusses the 

comments it received from interested 

persons during the process and the 

results of additional tests that it caused 

to be conducted, and announces the 

standby loss criteria for electric, gas, 

and oil storage water heaters that it is 

hereby adopting. DOE has modified tl1e 

criterion for electric storage water 

heaters and redefined instantaneous 

water heaters. The criteria for gas and 

oil water heaters have not been 

changed. DOE adopts these conclusions 

in a revised Table 9.3-1 in section V. 

EFFECTIVE DATE: The effective date for 

standby loss criteria for storage water 

heaters as presented in § 435.109, Table 

9.3-1, in section V of this Response and 

Announcement is June 12, 1990. 

ADDRESSES: Copies of DOE's analysis 

and test data may be viewed and/or 

obtained from the DOE Freedom of 

Information Reading Room, room lE190, 1000 Independence Avenue, SW., 

Washington, DC 20585, (202) 586-6020, 9 

a.m.-4 p.m., Monday-Friday, except 

holidays. 

FOR FURTHER INFORMATION CONTACT: 

Jean J. Boulin, Office of Codes and 

Standards, CE-43, U.S. Department of 

Energy, room 5E-080, 1000 

Independence Avenue, SW .. 

Washington, DC 20585, (202) 586-9444. 

Lawrence V. Robertson, Jr., Esq .. Office 

of General Counsel, GC-12, U.S. 

Department of Energy, room 6A-141, 

1000 Independence Avenue, SW .. 

Washington, DC 20585, (202) 586-9507. 

SUPPLEMENTARY INFORMATION: 

I. Historical Background 

A. Events Prior to October 8, 1989 

This portion of the historical 1 

background of the standards is 

presented at 54 FR 49724-49726, 

November 30, 1989. 

B. Events From October 6, 1989-

November 30, 1989 

These events are described at 54 FR 

49726, B. Events Subsequent to October 

6, 1989. 

C. Events Since November 30, 1989 

In compliance with the October 6. 

1989, Memorandum and Order of the 

Court, DOE has completed the following 

actions to date: 

1. Published, on November 30, 1989, a 

Preliminary Statement of Reasons for 

Adoption of Standby Loss Criteria 

(Preliminary Statement), with attention 

to the relevant statutory requirements, 

including those dealing with 

practicability, cost-benefit analysis, and 

impact on affected groups. (See 54 FR 

49724). 

2. Placed in the public rulemaking 

record, on November 30, 1989, all of the 

materials on which it relied in -

determining the storage water heater 

criteria it proposed to adopt on remand. 

The Preliminary Statement contained 

editorial errors. These errors were 

corrected at 54 FR 50341, December 6, 

1989. 

Subsequently. on February 2, 1990, 

DOE published a notice of Changes in 

Dates for Comment. (See 54 FR 3714). 

Notice was given that, on motion by 

plaintiffs. the October 6, 1989, Court 

Order was amended to extend the time 

allowed to comment on DOE's 

Preliminary Statement and, 

correspondingly, for DOE to respond to 

comments so received and announce 

appropriate standby loss criteria. The 

time for comment by the plaintiff and 

other interested persons was extended 

from January 15, to February 28, 1990; 

and the time allowed for the DOE's 

response from February 15, to May 15, 

1990. 

A Notice of Supplement to Public 

Record was published by DOE to advise 

of the availability of a "research grade" 

compiled computer code on diskette 

together with instructions explaining its 

use by the Department in determining 

the gas, electric and oil water heater 

examples set forth in the Preliminary 

Statement. (See 54 FR 3714, February z. 

1990). The source code compiled on diskette is that which is listed in 

Technical Support Doc11ment for 

Preliminary Statement of Reasons for 

Adoption of Standby Loss Criteria, 

November 1989, U.S. Department of 

Energy, Washington, D.C .. Table A-1. 

This was necessary because DOE, in 

response to a December 21, 1989, data 

request from GAMA, provided a copy of 

this information. In addition, DOE sent a 

copy of this information to all those who 

had requested or been sent copies of the 

November, 1989 Technical Support 

Document. 

Il. Applicable Statutory and Judidal 

Criteria 

Congress mandated, in section 

501(b)(1) of the Department of Energy 

Organization Act, 42 U,S.C. 7191(b)(1), 

that the Secretary of Energy, in 
 55FR23842

Federal Register I Vol. 55, No. 113 I Tuesday, June 12, 1990 I Rules and Regulations 

promulgating energy standards. must 

include "a statement of the research. 

analysis, and other available 

information in support of. the need for. 

and the probable effect of, any such 

proposed rule, regulation or order." In 

addition, section 501(d), 42 U.S.C. 

7191(d) provides that after the notice 

and comment period, the Secretary may 

promulgate a rule if the rule is 

accompanied by "an explanation 

responding to !he major comments. 

criticisms, and alterntives offered during 

the comment period." Section 310 of the 

Energy Conservation Standards for New 

Buildings Act. 42 U.S.C. 6839. 

specificaily provides that such 

standards must be "adequately 

11nalyzed in terms of energy efficiency. 

. economic cost and benefit. and 

impact on affected groups. in addition, 

section 302 of the Energy Conservation 

Standards for New Buildings Act. 42 

U.S.C. 6831(b)(2). requires DOE "ter 

achieve the maximum practicable 

improvements in energy efficiency and 

increases in the use of non-depletable 

sources of energy." In that regard. the 

October 6, 1989. Memorandum of the 

Court concludes that the word 

'practicable' in section 302(b](2J 

'rninforces the requirement of section 

310 that DOE take into account cos!· 

benefit and constituency concerns and 

not simply sacrifice all other concerns !o 

any reductions in energy use." Further 

standards-setting activities "shall be 

designed lo assure that such standards 

are adequately analyzed in terms of 

energy efficiency. stimulation of use of 

rion-deple!able sources of energy 

institutional resources, habitability, 

economic cost and benefit. and impact 

upon affected groups " 

Finally the Court's Memorandum 

further states that "increased energy 

efficiency must be weighed againsi 

potential increases in overall dollar 

costs arising from new standards under 

some articulated formula." 

m. Description of Storage Water Heater 

Standby Loss Criteria in Question 

The Storage Water Heater Standby 

Loss Criteria in question are part of 

Section 435.109 of the interim standards. 

entitled "Service Water HeatLTJ.g 

Systems," published at 54 Federal 

Register 4889 (January 30, 1989). This 

section identifies the scope, design 

principles, minimum requirements, and a 

prescriptive compliance method for 

service water heating systems and 

equipment. 

All water heaters and hot water 

storage tanks are addressed in Table 

9.3-1. This includes electric, gas, and oil 

storage water heaters. unfired storage 

tanks. gas and distillate oil 

instantaneous water heaters. and 

swimming pool water heaters. There is 

one exception to the standby loss 

criteria; storage water heaters and hot 

water storage tanks having more than 

500 gallons of storage capacity need not 

meet the standby loss requirements of 

Table 9.3-1 if (1) the tank surface area is 

thermally insulated to R-12.5 and (2) a 

slanding pilot light is not used. 

The standby loss criteria for electric, 

gas, and oil storage water heaters are 

highlighted in the right hand column of 

Table 9.3-1. Although the word 

"standby" could intuitively infer only 

that period of time when the storage 

water heater is not used, e.g., overnight, 

the criteria address the constant loss of 

heat energy experienced by a storage 

water heater while holding heated water 

not immediately being drawn for use in 

a building. A "storage water heater" is a 

water heater that has an input rating 

equal to or less than 4000 Btu/hr per 

gallon and a storage capacity of more 

than 10 gallons. 

The covered water heaters include the 

following: electric storage water heaters 

with a storage capacity of more than 120 

gallons or an input rating of more than 

12 kW; gas storage water heaters with a 

capacity of more than 100 gallons or an 

input rating of more than 75,000 Btu/h; 

and oil storage water heaters of more 

than 50 gallons or an input rating of 

more tI:ian 105,000 Btu/h. The covered 

electric storage water heaters are 

required to have a standby heat loss of 

less than 1.9 W /ft 2 • The covered gas 

and oil storage water heaters are 

required to have a standby heat loss of 

less than 1.3 + 38/V percent per hour. 

Standby loss is based on nominal 

temperature difference of 80°F, or the 

change in water temperature in percenl 

per hour based on a nominal 

temperature of 90°F. Table 9.3-1 is 

shown below. 

The test procedures that are to be 

used for certifying compliance with the 

standby loss criteria are described and 

explained in the Preliminary Statement 

at 54 FR 49730. 

l!:llWNG CODE MS0-01-M 
 55FR23842

23844 Federal Register/ Vol. 55, No. 113 /Tuesday, June 12, 1990 /Rules and Regulations 

Table 9.3-1 (January 30, 1989) 

Standard Rating Conditions & Minimum Performance of Water Heating Equipment 

Type Fuel 

Storage Electric 

1 Water 

I Heaters 

Gas 

Oil 

I I 

Storage! Input 

Rating 

Applica~le Test Procedure Minimu.~ Performance 

Capacity I 

(Gal) 

DOE Rating 

920 .:::_12 kW DOE Test Procedures, 1985 EF 

Code of Federal Regulations Title 10, Part 430 .::o.95-0.00132V 

>120 {or) >12kW 

~... 000 ·.,- .:::_100 

Btti/h 

ANSI C72.l - 1972 

DOE Test Procedures, 1985 

Code of Federal Regulations Title lQ, Part 430 

>100 (or) >75,000 ANSI Z21.10.3-1984 

Btu/h Gas Water Heaters 

w/Addenda Z21.l0.3a-1985 

.::_so 

.:::_75,000 

Btu/h 

.::_105,000 

Btu/h 

DOE Test Procedures, 1985 

Code of Federal Regulations Title 10, Part 430 

EF 

.::_0.62-0.0019V 

EF 

z.0.59-0.0019\f 

>0.59-0.0019V 

Eff. Loss 

SL 

<1.9 W/ft2 

SL 

<l.3+ 

38/V 

I I 

>105,000 

Btu/h 

E . 

c SL 

<1.3+ LJ >50 (ol) 

·.~~~~ - 03\: 30/V 

I 

9 CE690 Il.Cl.N 
 55FR23842

Federal Register I Vol. 55, No. 113 I Tuesday, June 12, 1990 / Rules and Regulations 

Table 9.3-l (January 30, 1989) 

Standard Rating Conditions & Minimum Performance of Water Heating Equipment (Cont.) 

Type 

Applicable Test Procedure Minimum Performance 

Input 

Class Fuel Capacity Rating 

Unfired 1 All All 

Storage Volume In[>uts 

Instantaneous Gas - All ANSI Z21.10.3-1984 

Inputs 

Distill All 

011 - Inputs 

Pool Gas/ All AMS! Z21.56-1986 

Heaters Oil - Inputs 

Notes for Table 9.3-1: 

Terms Defined: 

l. EF = Energy factor, overall heater efficiency by DOE Test Procedure 

Et Thermal efficiency with 70°F, •T 

- HL 

- <6.5 

Btu/ll"ft2 

Et -

80\ -

Ee -

83\ -

Et -

78\c -

E0 = Combustion ef!icienc2, 100 percent - flue loss when smoke a 0 (trace is permitted) 

SL = Standby loss in W/ft based on 80°F, •T, or in percent per hour based on nominal 9o•F, AT 

HL = Heat loss of tank surface area 

V a Storage volume in gallons 

Insert IHustralio~s) 737A-738 

BILLING CODE 6450--0f-C 

10 CE698 Il.CLN 

next page, page 12 

23845 
 55FR23842

23846 Federal Register / Vol. 55, No. 113 / Tuesday, June 12, 1990 / Rules and Regulations 

IV. Summary of Public Comment 

Received by February 28, 1990, on the 

November 30, 1989, Preliminary 

Statement of Reasons and DOE 

Responses 

A.Summary 

At the close of the comment period on 

February 28, 1990, DOE had received 

responses from nine individuals, firms, 

and organizations. A number of those 

cofil111ents v;ere duplicative in nature. 

Tl1e comments dealt primarily with 

specific sections of the Preliminary 

Statement, including those dealing with 

DOE's assumptions in modeling standby 

less in gas and electric water heaters, 

the methods used to compute 

practicability and cost-benefit, and the 

impact on affected groups. There were 

also several general comments. It should 

I:,,; noted that reference is made in many 

of the comments to "DOE's proposed 

standards." The Energy Conservation 

Standards for New Commercial aad 

Multi-Family High Rise Buildings that 

DOE promulgated on January 30, 1989 

(54 FR 4538), are not proposed 

standards. The standards became 

mandatory for aH Federal construction 

agencies on July 31, 1.989. After that 

clate, all new Federal buildings fitting 

tl::e category must be designed to meet 

or exceed the standards. This, of course, 

does not include portions of the standby 

loss criteria as specified in the October 

6, 1989, Court Order. 

The nine parties commenting included 

one trade association (GAMA), two 

from one professional society (American 

Society of Heating, Refrigerating, and 

Air-Conditioning Engineers, Inc. 

[ASHRAE]), three water heater 

manufacturers (Rheem Corporation, 

State Industries, Inc., and BradfordWhite Corporation}, a State energy 

office (California Energy Commission), a 

public interest group (National 

Resources Defense Council), and one 

individual (Lawrence G. Spielvogel of 

Lawrence G. Spielvogel, Inc.). The 

cc1mments addressed numerous issues; 

therefore, DOE has divided them into 86 

individual comments. Each comment is 

addressed in this Response and 

Announcement, and a response is 

provided for each. The comments are 

grouped by issue. Duplicate and similar 

comments are grouped and responded to 

as a single comment. 

The covered water heaters addressed 

by this Response and Announcement 

are defined in the DOE standards by 

fuel type, storage capacity, and input 

rating rather than by occupancy served 

(residential or commercial). For 

example, some small storage capacity, 

low input storage water heaters are 

quite appropriate for use in some 

commercial buildings. However, to 

facilitate discussion of comments and 

DOE's responses, the term commercial, 

when used in regard to storage water 

heaters, hereafter refers to the storage 

water heaters covered by the standby 

Joss criteria in question defined in 

Section III. 

The majority of the comments 

disputed the standby loss criteria, 

although a few supported the DOE 

criteria. One comment suggested a more 

stringent level for commercial electric 

storage water heaters. 

In developing the Preliminary 

Statement, as well as in responding to 

previous requests for information from 

the water heater industry, DOE has 

provided detailed documentation in 

support of its analysis. In responding to 

comments, DOE again is providing full 

documentation. This includes further 

computer analyses and tests 0'1 selected 

commercial electric and gas water . 

heaters. DOE had anticipated a similar 

level of supporting documentation 

would be provided in the comments 

submitted by the interested trade 

association and water heater 

manufacturers. However, this was not 

the case. Rather, in a number of 

instances these persons advanced 

arguments and asserted conclusions that 

were not substantiated by 

accompanying data or documentation. 

A Congressional mandate requires 

DOE to establish standards that achieve 

the maximum practicable levels of 

energy conservation, and DOE intends 

to establish standards based on the data 

that is available, and has been made 

available to it. In the case of water 

beaters, DOE has based its decisions on 

information derived from its OVii'11 

research, the standards development 

process of the Standing Standards 

Committee-90R, of ASHRAE, and 

information provided by the industry. 

Some industry information indicates 

that the progression of the water heater 

standbyloss criteria, from established 

standards and practice, through the 

criteria establish by DOE, can be met by 

the industry through normal product 

improvement. DOE's analysis indicates 

likewise. 

B. General Comments 

1. DOE received several general 

comments concerning the practicability 

of the standby loss criteria for natural 

gas and electric water heaters., No 

specific comments were received 

regarding oil water heaters, although 

one comment on gas water heaters also 

alluded to oil water heaters. Three who 

commented strongly endorsed the DOE 

standby loss criteria. Five others 

contended that the DOE water heater 

standby loss criteria for gas and electric 

water heaters are too stringent, and that 

DOE's method of analyzing potential 

energy savings and cost-benefit are 

flawed. 

Thomas P. Wutka, CIGNA 

Corporation and Chairman of the 

ASHRAE Standing Standards Project 

Committee-90R, stated that the 

evidence DOE provides in its 

Preliminary Statement, "clearly 

demonstrates the cost-effective 

feasibility of the standby loss 

requirements for storage water heaters." 

The ASHRAE 90R Committee also 

requested that DOE not loosen the 

requirements simply because other 

groups assert that the requirements are 

unreasonable. Mr. Wutka asserted 

farther that those groups seeking an 

injunction on the water heater standby 

loss criteria have not offered any 

convincing evidence that the criteria 

should be amended. Mr. Wutka and Dr. 

David Goldstein of the Natural 

Resources Defense Council (NRDC), and 

a member of the ASHRAE 90R 

Committee provided a letter from 

American Appliances, a water heater 

manufacturer, in support of the standby 

loss requirements, which stated "we feel 

that they are technically achievable by 

that time [1992] without unreasonable 

cost". While there was a follow-up letter 

qualifying these comments, DOE found 

it unpersuasive. Dr. Goldstein indicated 

in his comments that the standby loss 

levels were less stringent than they 

should be to meet the Congressional 

mandate of achieving the maximum 

practicable improvements in energy 

efficiency. 

Dr. Goldstein also said that the new 

analysis provided by DOE in the 

Preliminary Statement clearly 

demonstrated that a more stringent 

criterion for electric water heatere-1.52 

W /ft2-can be justified. Dr. Goldstein 

provided procedural, technical, and 

other background information to 

substantiate these claims. 

Finaily, Ms. Elena Schmid of the 

California Energy Commission (CEC} 

stated that the CEC found that a more 

stringent standby loss level could be 

used for gas water heaters. However, 

Ms. Schmid said, at the current time, a 

more stringent level has not been 

reviewed thoroughly enough to warrant 

that DOE assess more stringent criteria. 

Contending that the DOE water heater 

standby loss criteria for gas and electric 

water heaters are too stringent, Mr. 

Denver Collins of State Industries, Inc., 

a water heater manufacturer, stated that 

DOE needs an education in commercial 

water heaters and recommend~ that 

DOE work in good faith with the water 
 55FR23842

Federal Register / Vol. 55, No. 113 / Tuesday, June 12, 1990 / Rules and Regulations 23847 

heater industry to arrive at reasonable, 

obtainable efficiency goals based on 

actual test data rather than on invalidated,_erroneous computer models. 

DOE Response: DOE agrees with the 

three who endorsed the DOE standby 

loss criterion for the gas water heaters. 

DOE believes that the water heater 

standby loss criterion for the gas water 

heaters are practicable. While DOE 

believes that there is some data to 

suggest that more stringent [gas] water 

heater standby loss criteria would be 

reasonable, it agrees with the comment 

made by the CEC that a more stringent 

level has not been reviewed thoroughly 

enough to warrant that DOE set more stringent criteria at this time. DOE also 

believes that Federal construction 

agencies that specify storage water 

heaters in the design of their buildings 

will find water heaters on the market to 

meet these criteria at life-cycle costeffective prices. 

In response to several of the other 

commenters on the electric water heater 

criterion, DOE has performed tests and 

done additional analysis that cause 

DOE to believe that slightly less 

stringent criterion for electric water 

heaters are warranted. A more detailed 

discussion is provided below. 

DOE appreciates the receipt of diverse 

comments. It is through public comment 

that DOE hopes to improve its standardmaking process. However, it is 

important that those who do comment 

on DOE standards substantiate their 

views and document or reference 

published material to support their 

statements. Statements of opinion and 

substantive comments must be 

supported by essential documentation. 

Finally, DOE has attempted to work 

with the industries affected by its 

standards. Every effort has been made 

for public review and comment, and 

through ASHRAE, DOE has worked 

with the most widely recognized of all 

energy conservation standards 

development bodies. In that regard, DOE 

forcefully rejects the suggestion that it 

has not been responsive to the concerns 

expressed by industry representatives. 

2. Mr. Paul G. Daugirda of Rheem 

Corporation and Mr. Eugene L. West of 

Bradford-White Corporation, both water 

heater manufacturers, stated that none 

of their current electric or gas model 

commercial storage water heaters would 

meet the standby loss provisions of the 

proposed DOE standards. Mr. Daugirda 

said that DOE's inexperience in the 

design and construction of water heating 

equipment led to optimistic assumptions 

and unrealistic conclusions. 

DOE Response: While it is expected 

that some commercial storage water 

neaters will not meet the criteria set by 

DOE, DOE continues to believe that the 

criteria are fair and not onerous to 

·water heater manufacturers. It is not 

uncommon in any area of technology 

that some current models will not meet 

the new criteria when more stringent 

standards are set. If the standards are 

developed fairly and are not unduly 

burdensome, it is then up to the 

purveyor of that technology to make the 

decision whether to continue to market 

specific equipment. If the decision is 

made to market that equipment, then the 

necessary modifications will have to be 

undertaken. 

DOE believes that its water heater 

standby loss criteria, with some 

modification to the electric storage 

water heater criterion, are fair and not 

unduly burdensome. It further believes 

that many current water heaters can be 

easily and cost-effectively modified to 

meet the standards. DOE has produced 

substantial information to document its 

rationale, including information that is 

discussed later in this Response and 

Announcement. 

3. Rheem Corporation estimated its 

lost revenue, on an annual basis from 

Federal sales, to be approximately 

$800,000 if the standby loss criteria are not modified. Mr. Daugirda stated that if 

various States, especially large market 

States like California and New York, 

adopt the Federal standards, the lost 

sales revenue could easily amount to 

several million dollars. 

Mr. Daugirda also indicated that to 

stay in business in the Federal sector, 

the Rheem Corporation would have to 

re-tool its production facility to produce 

entirely new models. The company now 

has eight basic designs of gas-fired 

water heaters in the 75,500 to 100,000 

Btu/h input range, a category of product 

that comprises 23 percent of the 

company's commercial water heater 

business. Only one of these designs has 

a flue damper. To modify these designs as needed to comply with the DOE 

criteria would require the addition of a flue damper to all but one design, and 

increased insulation and enlargement of 

the casing for all eight designs. Mr. 

Daugirda claimed these to be radical 

changes that would increase 

manufacturing costs by approximately 

50 percent over models without flue 

dampers. He stated further that the total 

standby loss energy savings would not 

come close to defraying the additional 

costs of the units. 

DOE Response: The company 

provided no basis for choosing not to 

build units that meet the standby loss 

criteria. Rather, it acknowledges that it 

currently produces a product line that uses flue dampers, but provided no 

additional information as to how and 

why the production line would have to 

be changed to accommodate the 

addition of the flue dampers and 

insulation to Rheern's other currently 

available water heaters. It further stated 

that the addition of a flue damper will 

increase manufacturing costs by 50 

percent over models without flue 

dampers, but again, provided no 

explanation or supporting information. 

Mr. Daugirda implies that the 

company would lose money by building 

units to the DOE standby loss criteria. 

However, this is not logical assuming 

that the standby loss criteria become 

mandatory in wide segments of the 

water heater market. The setting of 

standards automatically creates a 

market and market forces would set the 

unit price. If this were to happen, the 

question for manufacturers becomes 

whether they choose to reenter the 

market with a modified product which 

can compete in that market. ASHRAE/ 

!ES Standard 90.1-1989 has been 

published with standby loss criteria 

similar to those in the DOE Interim 

Standards. A number of States and local 

governments have expressed interest in 

adopting the DOE or ASHRAE/IES 

standards. It is DOE's belief that if the 

ASHRAE/IES Standard 90.1-1989 

becomes the operable standard across 

the country, then a very large market 

will be created. 

In the meantime, DOE has an 

obligation to set standards that must 

"achieve the maximum practicable 

improvements in energy efficiency." 

[Public Law 94-385] Given that water 

heater units that meet the standards are 

currently available and that these units 

come within the life-cycle cost 

guidelines (subpart A of 10 CFR part 

436) under which the Federal 

government operates, it is DOE's 

responsibility to set standards that most 

benefit the Federal government. 

4. Dr. Goldstein of NRDC requested 

that DOE conduct further analysis of the 

standards on affected groups. Dr. 

Goldstein identified taxpayers as the 

primary group affected by the DOE 

standards since they are responsible for 

the energy bills of buildings covered by 

mandatory standards. 

In addition, Dr. Goldstein stated that 

the general public is an interested party 

because the Federal standards, coupled 

with the similar ASHRAE standards, 

will influence or even determine the 

design of most commercial buildings in 

future years. 

According to Dr. Goldstein, failure to 

promulgate energy savings requirements 

that are costceffective-that is, ones 

whose cost to society is less than the 

cost of new energy supply-raises utility 
 55FR23842

Federal .Register I Vol. 55, No. 113 I Tuesday, June 1.2, 11}90 l Rules and Regulations 

bills for everyone. This results in excess 

and unnecessary consumption of fossil 

fuels with adverse effects on the 

nation's energy security, air quality, and 

the global climate. He said the 

standards proposed by ASHRAE are 

exceptionally cost-effective-the DOE 

Technical Support Document suggests 

paybackperiods of less than three 

years. For this reason, he said, these 

other parties would be adversely 

affected if DOE fails to adopt a standard 

at least as strong as that adopted by 

ASHRAE. 

DOE Response: It is fully DOE's 

intention to adopt standards that are 

practicable for both the groups that must 

a bide by the standards and those groups 

that would be affected, in the long term., 

should reasonable standards not be 

adopted. In order to reassess its position 

on the standby loss criteria, DOE has 

performed further technical and costbenefit analyses based on the comments 

received. Based upon its review and 

analyses, DOE believes that the 

standards it has promulgated, and those 

it will modify through this document, are 

practicable for groups administering and 

complying with the standards and also 

fair to the general public. 

C. Comments on DOE's Basic 

Assumptions in Modeling Commercial 

Storage Water Heaters 

DOE received several general and 

specific comments regarding the 

assumptions used in modeling different 

capacity and fuel types (gas, oil, and 

electric) of water heaters. The computer 

rnodelingwas done for several purposes. 

First, to establish a baseline for current 

capacity and fuel types of water heaters. 

Second, to determine the modifications 

that would be needed, when necessary, 

so these units could meet the DOE 

standards. Third, to evaluate the energy 

savings potential of lowered standby 

loss levels. Lastly, to determine the costbenefit of the water heaters at the 

lowered standby loss levels. 

It should be noted that not every 

water heater currently available was 

modeled. Rather, the analysis was 

performed on a range of generic water 

heaters ofdifferent sizes, shapes, and 

power .inputs. This approach was taken 

to evaluate the effects of specific 

standby loss criteria and not as a way of 

evaluating current models. To respond 

to public comments, DOE did, followiI).g 

the public comment period, test two 

units-one gas-fired and another 

electric. These tests were performed to 

help verify assumptions made in 

modeling and to assess tests reported by 

the industry. 

A thermal modeling approach was 

used to determine the standby water 

heater losses through the tank jacket. 

The thermal model used in the analysis 

is a steady-state model based on first 

principles of thermodynamics. It uses 

universally accepted equations for . 

calculating the heat flow from the 

heated water and acceptable values of 

thermal resistance for various materials 

in generic models. Due to the wide 

variety of water heaters on the market, a 

generic model was used tbatmade no 

attempt to calculate subtle design 

differences between models and 

manufacturers. Rather the model took 

account of broadly recognized 

characteristics of storage water healers 

that significantly affect standby losses. 

Where the inputs to the model were 

known to vary significantly, a range 

with high, medium, and low inputs was 

tested in the model to establish the 

"sensitivity" to the variations. For 

example, when there were questions 

about the values assigned the emissivity 

of the jacket, several runs of the model 

were made varying the emissivity for 

each run and showing the sensitivity of 

the results for each variation. 

Figures 1 and2 illustrate the heat 

losses accounted for by the model. The 

model accounts for 100 percent of the 

standby losses from the jacket. It did not 

originally account for the other losses 

due to fittings, controls, and flue in the 

case of gas units. DOE did, however, 

add losses to the model to account for 

these fitting losses. This information 

was based on available data, which is 

summarized later in this document. The 

water heater tank was modeled as a 

right cylinder (having its axis 

perpendicular to the base) containing 

water at a uniform temperature, 

surrounded by air, which is also at a 

uniform temperature. Water and air 

temperature were selected to 

correspond to those indicated in the 

appropriate test procedure for the 

specific water heater type. 
 55FR23842

Federal Register / Vol. 55, No. 113 /Tuesday, June 12, 1990 / Rules and Regulations 23849 

JACKET TOP 

RELIEF FITTING 

INLET FITTING OUTLET FITTING 

ELECTRIC 

WATER 

HEATER 

JACKET SIDE 

DRAIN FITTING 

CONTROLS 

JACKET BOTTOM 

COMPONENTS OF HEAT LOSS 

Figure 1 - Heat Loss Components for Electric 

Water Heaters 

Use of the steady-state thermal model 

allows calculation of heat flow rates 

from the water in the tank to the 

ambient air with varying levels of tank · 

insulation. This approach permitted 

DOE to perform a sensitivity analysis to 

determine the level of insulation 

required to meet the standby loss 

criteria. The required insulation levels 

for different water heater types and 

sizes are listed in the Preliminary 

Statement and the accompanying 

Technical Support Document. 

As described above, the thermal 

modeling approach used by DOE is 

based on a steady-state analysis. The 

actual standby loss tests of water 

heaters conducted in accordance with 

the test procedures are dynamic tests 

covering a 48 hour period. Actual 

standby loss tests are required to be 

conduc"ted over an extended period of 

time due to the complexity of making 

accurate measurements of heat loss on a 

steady-state basis. The test procedure 

measures the energy input required to 

maintain the water at the setpoint 

temperature, the input energy required 

to maintain the setpoint temperature is 

exactly equal to the steady-state heat 

loss of the water heater. 
 55FR23842

. 23850 Federal Register i Vol. 55, No. 113 ./·Tuesday, June 12, .1990 ./ Rules .and Regulations 

TOP 

CLEANOUT 

FLUE 

GAS 

WATER 

HEATER 

BOTTOM 

FITTINGS 

JACKET 

COMPONENTS OF HEAT LOSS 

Figure 2 - Heat Loss Components for Gas Water 

Heater 

The steady-state modeling approach 

used by DOE did not attempt to model 

the standby loss test, but was instead 

designed to give ·results equivalent to 

the standby loss test. The reference to 

the test procedure used as the basis for 

the standby loss calculation shown in 

the Preliminary Statement and the 

accompanying Technical Support 

Document is a reference to the specific 

standby loss equation used in the 

calculation. 

1. Faulty Modeling 

DOE received several general 

comments from Rheem Corporation, 

State Jndustries, Inc., Bradford-White 

Corporation, and GAMA asserting a 

lack of knowledge by DOE regarding 

water heaters, and, therefore, 

questioning its expertise in compiling a 

rational computer model. Specifically, 

the comments addressed the precision 

with which DOE modeled specific types 

of water heaters. For example, 

comments from Rheem, Bradford-White, 

and GAMA related to size of water 

heaters modeled, suggesting that DOE 

reviewed too large a range of water 

heater sizes, and that the market was 

primarily within one size-100 gallons 

and less. 

DOE Response: DOE believes that the 

issues are whether .the computer model 

is reasonable for the entire range of 

water heaters covered by the standards, 

and whether the assumptions used are 

conservative enough to be inclusive of 

most water heaters and to establish the 

practicability of the criteria. Most of the 

comments were directed at a relatively 

small portion of the storage water heater 

market. 

However, to provide some finality to 

resolving the question of model 

assumptions, DOE directed the National 

Institute of Standards and Technology 

(NIST) to purchase two "off-the-shelf' 

storage water heaters, one electric and 

one gas, and test the units. The results of 

the tests were then compared with the 

results generated by DOE's computer 

model. After adjusting input 

assumptions for fitting and control 

losses for the electrical unit, close 

correlation was found between the 

results. Thus, the computer model 

showed itself to be consiStent with the 

NIST test data. 

The geometry and size of water heater 

flues were also areas in which DOE 

received negative comment. It was 

asserted that DOE only modeled uni.ts 

with a single flue through the water 

heater tank. The three who commented 

on this subject stated that most water 

heater designs include a multiple flue 

arrangement through the tank. The hot 

gases that pass through the flues are 

then collected at the top of the tank and 

released through a single flue hole. The 

comment was made that the geometry 

and surface area for these water heater 

types would have a significant effect on 

standby loss and that DOE had not· 

accounted for this type of water heater 

in its modeling. As stated previously, it 

was not DOE's intention to construct a 

model that handled specific water 

heaters, rather it was constructed to 

provide conservative data for an entire 

range of water heaters. In this instance, 

DOE allowed for a range of percent heat 

losses through the flue and picked what 

it thought was the most appropriate 

value. However, it also found that the 

appropriate value may vary depending 

on input firing rate. 
 55FR23842

Federal Register I Vol. 55, No. 113. I Tuesday, Junel2, 1990 /,Rules and, Regulations 23851 

A sensitivity analysis was performed 

to determine the effect on tank and 

jacket surface area as a result of 

considering multiple flues as opposed to 

a single flue. For this analysis a 100-

gallon gas water heater with the same 

dimensions as those shown in Table 1 of 

the Preliminary Statement v1ras 

analyzed. For each case analyzed the 

tank volume and tank height were 

assumed ta be constant. The unit was 

assumed to be insulated with 2 inches of 

insulating material in order to establish 

the jacket diameter. As additional flues 

were added, the tank and jucket 

diameters were increased to 

Table 1 

accommodate the additional flue area 

while maintaining a constant water 

volume. Table 1 in this Response and 

Announcement indicates the differences 

between the different configurations is 

not significant for the purpose of altering 

the method of establishing the slandbv 

loss criteria. 

SENSITIVITY OF SURFACE AREA CP.l'u~GES TO VARIOUS FLUE CONFIGURATIONS 

NUMBER 

.OF 

FLUES 

FLUE NET TANK JACKET TANK JACKET TA.~K JACKET CHANGE IN CHANGE IN 

PIAl'1ETER AREA DIAMETER D!AMETER HEIGHT HEIGHT AREA 1'.F.EA TANK AREA JACKET AREA 

(in.) (sq. in.) (in.)· (in.) (in.) pn.) (sq. ft.)(sq. ft.) (\) (\) 

1 6 443.01 23.75 27.75 55.70 57.70 31.94 39.13 o.oo -0.00 

4 3 443. 01. 23.75 27.75 55.70 57.70 31.94 39.13 0.00 0.00 

6 3 457.15 2"4 .13 28.13 55,70 57.70 32.49 39. 72 1. 74 1.50 

8 3 471. 29 24.50 28.50 55.70 57.70 33.04 40.30 3.45 2.99 

10 3 485.43 24.86 28.86 55.70 57.70 33.58 40.87 5.15 4.45 

12 3 499.56 25.22 29.22 55.70 57.70 34.12 41.44 6.82 S.90 

14 3 513.70 25.57 29.57 55.70 57.70 34.65 42.00 8.48 7.33 

16 3 527.84 25.92 29.92 55.70 57.70 35.17 42.55 10.12 e.74 

18 3 541.97 26.27 30.27 55.70 57.70 35.69 43.10 11. 74 10.14 

20 3 556.11 26.61 30.61 55.70 57.70 36.20 43.64 13.34 11.52 

22 3 570.25 26.95 30.95 55.70 57.70 36.70 44.18 14.93 12.69 

NOTE: Analysis based on 100-gallon gas water heater described in Table l of the Preliminarj Statement 

2. Specific Comments 

a. jacket Heat Loss. Lawrence G. 

Spielvogel of Lawrence G. Spielvogel, 

Inc., stated that DOE's assumptions 

were flawed because the model 

assumed that all standby heat loss from 

the jacket of a water heater represents 

. wasted energy. Mr. Spielvogel stated 

that virtually all water heaters are in 

heated space in buildings. Therefore, 

jacket heat loss provides useful heat to 

the space, reducing the amount of heat 

thal is otherwise required. The space in 

which water heaters are located is 

virtually never air conditioned. Since 

there is no energy penalty for air 

conditioning, jacket losses are losses 

only during the months when there is no 

heating. Throughout the continental 

United States this period of time 

typically ranges from several months to 

about six months per year. In addition, 

the ambient temperature is usually 

higher than 70° to 72° F during those 

months. This further reduces jacket heat 

loss. Therefore, according to Mr. 

Spielvogel, the benefit associated with 

reducing jacket loss is only a fraction of 

that set forth in the DOE analysis. Mr. 

Spielvogel did not provide data to 

support this argument. 

DOE Response: No supporting data 

was provided for the comment. DOE 

believes that most water heaters are 

located in mechanical rooms. Such 

spaces are generally vented to the 

outside and the heat is lost when 

vented. Water heater standby loss is not 

calculated in the sizing of heating of 

such spaces and reduction of this heat 

loss is not likely to have any benefits for 

down sizing of equipment. 

Water heaters located in conditioned 

space, likely will be in core areas of the 

building, Such core areas of a building 

are very often cooled year-round. In 

such conditions, the standby loss 

requires additional energy to cool the 

excess heat. 

In those cases of water heaters 

located in heated spaces, DOE believes 

that many of these spaces are both 

heated or cooled, or adjacent to and 

influenced by spaces that are both 

heated and cooled. In such cases, DOE 

believes the benefit from heat loss in the 

heating season is lost to the cost of . 

cooling and ventilation in the swing and 

cooling seasons. 

DOE believes that its assumptions are 

correct nationally. It should also be 

noted that Sections 11 and 12 of the 

standards make provision for taking 

advantage of otherwise unaccounted for 

benefits in the standards through a 

whole building energy analysis. 

Furthermore, the DOE standards do not 

assure water heater placement 

regardless of current practice. DOE does 

not believe it to be practical to make 

this a requirement. Therefore, units 

should be designed for use in nonconditioned areas. 

GAMA also commented on jacket 

heat loss, contending that DOE changed 

its criteria by allowing for insulation to 

be placed, either internal or external of 

the water heater jacket. Furthermore, 

GAMA contended the test procedures 

used to evaluate the water heaters do 

not make any accommodation for 

adding insulation on the outside of the 

water heater jacket prior to conducting 

the test. GAMA indicated that the 

ANSI/ASHRAE/IES Standard 90A-1980 

standby loss requirements have always 

been applied to the water heater without 

external insulation. In using the test 

procedure and adhering to Standard 90, 
 55FR23842

23852 Federal Register / VoL 55, No. 113 I Tuesday, June 12, 1990 / Rules and Regulations 

the only insulation considered is that 

which is placed between the tank and 

the water heater jacket at the time of 

producti-On. GAMA argued that no 

enforcement agency or any other 

standard-setting organization recognizes 

the option of insulating the outside as a 

means of establishing compliance. It 

contended that if DOE truly intended 

that its standby loss criteria could be 

satisfied by insulating the outside of the 

water heater, the dispute with DOE 

could be resolved very simply. DOE's 

standards could be revised to specify 

the standby loss requirements currently 

found in ANSI/ ASHRAE/IES Standard 

90A-1980 and separately require that all 

commercial storage water heaters be 

wrapped with an external insulation 

blanket at the time of installation. The 

R-value of the external insulation could 

be specified to provide the desired level 

of standby loss. . DOE Response: There is nothing in the 

test procedures that would prevent the 

testing of a storage water heater with 

additional insulation external to the 

· metal jacket. From the standpoint of · 

testing water heaters, it does not matter 

whether the insulation is internal to the 

water heater jacket or external. as DOE 

has found in the tests conducted at. 

NIST. Therefore DOE conducted its 

analysis to include all possibilities. 

DOE believes that external insulation 

is not a preferred solution if the 

insulation is of the type that can be 

easily damaged in operation. For 

example; low quality insulation v.Taps 

can become detachedeasily and.can 

disintegrate with time; extern.al 

insulation can be torn or .otherwise 

disabled unless covered by a stiff ;;hell; 

and routine maintenance to external 

insulation is subject to the rigors of 

maintenance, moistur,e, and animal 

destruction. DOE does not intend to 

engineer a specific solution for external 

insulation, but is aware of foam 

insulations that might be used 

externally. 

b. Set Water Temperatures. Mr. 

Spielvogel and GAMA commented on 

the assumption used for water 

temperature. Mr. Spielvogel stated that 

DOE is incorrect in its p.ssumption that 

hot water is stored at 140° F to 160° F. 

He stated that heater temperatures 

typlcaliy are set in the range of 110° F to 

120° F. Both comments indicated that 

even in the DOE standards-Section 

9.3.4-DOE suggests water heater no than 120° F, with 

~~·~n.ovu of booster heaters for any 

DOE 

received no supporting with which 

to scrutinize the assertion. it appearn 

Iha! the commenteri:; have 

misinterprete~d the standards. Section 

9.3.4.1.1 of the DOE Interim Standards 

suggests that w·ater temperatures need 

not be higher than 120 °F except for 

certain uses. This is a suggestion only, 

as nowhere in the standards are water 

temperature levels set. At outlets for a 

particular use over 120 °F, DOE requires 

separate remote heaters or booster 

heaters. For example, a restaurant in 

what otherwise is an office building 

would require higher water . 

temperatures for dishwashing and 

sterilization. 

In its analysis DOE uses the 140 °F to 

169 °F to reflect the tank temperatures 

from the only data available to DOE at 

the time, a End-Use Load and Consumer 

Assessment Program (ELCAP) study 

sponsored by the Bonneville Power 

Administration. In this study 

commercial building tanktemperatures 

were .not studied. Data from residential 

wafer heater tank temperature (409 

·temperatures taken) shows the average 

temperature to be 137 °F, with a range of 

104 °F to 195 °F. Multiples of tank 

temperatures clustered at standard 120 

°F, 130 °F, and 140 °F values. The DOE 

assumption of140 °F was based on what 

was likely to occur. c. 24-Hour Per Day Use. Mr. 

Spielvogel and GAMA indicated that it 

was presumed that the covered water 

heaters were used 24-hours per day. Mr. 

Spielvogel indicated that increasingly it 

is usual practice to tum off all types of 

water heaters when non-residential 

buildings are unoccupied. This is 

accomplished by seven-day time clocks 

or with energy management systems. 

Therefore, according to him, in a typical 

commercial building. the water heater is 

likely to be off more than half the hours 

in a year. GAMA states that a good 

average usage is 14 hours per day. 

DOE Response. The intent of the 

standby loss criteria is to reduce heat 

losses. In general these losses can be 

reduced through the addition of 

insulation. Additional insulation 

benefits the efficiency of the water 

heater whether it is in the standby mode 

or in an operational mode. 

Both the ANSI and DOE test 

procedures dictate that the units be 

tested in the standby mode. The test 

procedures are designed to isolate the 

losses arising from the standby loss of 

the unit. In actual operation, the unit 

will be in for part of the time, 

and will be and circulating water 

for the other part. In either case, the 

additional insulation required to meel 

the loss criteria will serve to 

rf,duce losses of 

With respect to the use of time 

and energy management systerns, DOE 

d,id not receive any data or""''"''~" 

information to substantiate from the 

comment. DOE does not have any 

information that indicates that either 

time clocks or energy management 

systems predominate in turning off 

commercial water heaters during times 

of non-use. The data it does have from 

the ELCAP study sponsored by the 

Bonneville Power Administration 

indicates that a very small percentage of 

commercial water heaters are 

controlled. 

d. Sizes of Units Modeled. Several 

comments stated that DOE's choice of 

volumetric capacities is not 

representative of the marketplace. The 

comments indicated that the majority of 

commercial gas storage water heater 

models have storage volumes in the 

range of50 to ioO gallons, with the two 

most common sizes being 75 to 100 

gallons. Further, the comments indicated 

that the formulas and criterion 

employed to model commercial gas-fired 

water heaters were developed only to 

cover a narrow range of residential size 

water heaters with specific physical 

characteristics. 

Rheem Corporation commented that 

99. percent of water heaters sold have 

volumetric capacities of 100 gallons or 

less. Mr. Daugirda also stated that 

modeling units of greater capacities. 

when the formula used to set the 

standby levels is tilted in favor of larger 

units, gives misleading results, 

Bradford-White Corporation indicated 

that 80 percent of its gas-fired water 

heaters sold were in the 75 to 100 gallon 

size (100 percent of the electric water 

heaters were the 50to120 gallon range). 

Mr. West also indicated that the larger 

than 100 gallon for gas, and 120 gallon 

for electric, water heaters have sales 

prices of six to ten times the price of 

typical, smaller-size models. 

Mr'. West pointed out that the electric 

water heaters DOE examined-50, 120, 

and 170 gallons-do not accurately 

represent common models. The 

predominant volume sizes of 

commercial electric storage water 

heaters range from 50 gallons to 120 

gallons. Annual shipments of models 

within this volume range account for 

over 90 percent of the total commercial 

electric storage water heater shipments. 

The typical line consists of a 50- or 52-

size, an 80-, 82- or 85-gallon size. 

and a 120-gallon size. The DOE anaiysis 

should have included a modal with a 

volume of 80, 82 or 85 gallons. 

GM!A indicated that the sizes 

modeled by DOE to the 

sizes for only one company (A.O. 

and tha~ the company offered 

the greatest variety of larger volume 

models. These models, however, are 
 55FR23842

Federal Register /Vol. 55, No. 113 l Tuesday; June 12, 1990 /rRules and Regulations 23853 

equipped with power gas burners and 

are not representative of typical . 

commercial gas storage water heaters. 

DOEResponse:The predominant size 

· capacity of commercial gas an.d electi::ic 

storage wat(;lr heaters sold in the United 

States may well be in the .50 to 120 · 

gallon range. OOEdoes not have data 

confirming that information despite 

several requests to the irn;lmitry that 

such information be furnished. It is also . not known if the manufacturers! . . . 

assertion includes both comme.rcial and 

residential water heaters. 

However, DOE has used an analysis 

that is not dependent on mix of market 

sales. DOE has analyzed a wide-range 

of sizes fr1a t are covered by the criteria. 

It does not matter that certain sizes 

predominate the market. DOE has the 

obligation of setting levels for all storage 

water heaters that are within the scope 

of the standards. Hs study is valid if it 

adequately covers the range of water. 

heaters covered by the criteria. Thus, 

the study need not be a weighted 

average. study of the units sold., The. 

study addressed the issue by looking at 

a range of sizes and performing 

sensitivity analyses to identify 

parameters that might be sensitive to, 

change. The study ~learly shows that 

the range of units addressed was quite 

adequate to address the range of units 

about which Mr. West expresses 

concern. 

With respect to the comment 

concerning types of gas-fired water 

heaters modeled, while it is true that the 

units were modeled after the large 

power gas burner heater line of one 

·manufacturer, the models in the analysis 

did not attempt to utilize a power burner 

design. The models were chosen simply 

to provide representative tank 

dimensions of large gas-fired storage 

water heaters: Because the analysis was 

looking specifically at jacket losses, the 

concern about the powered burners and 

therefore, the cost of these units, is not 

warranted. 

D. Comments on Eiectric St.orage Water 

Heaters 

1. Specific Comments 

The majority of the comments 

pertained to gas storage water heaters. 

However, GAMA and each of the 

manufacturers that commented produce 

both gas and electric water heaters and 

have provided comments on each type. 

a. Water Heater CharacteristicsElectric. DOE received comments from 

GAMA and Rheem Corporation. They 

indicated that DOE was incorrect in 

assuming that commercial electric 

storage heaters are constructed the 

same as residential electric models. 

They stated that there are two major 

differences-:the larger surface. area cf 

the. part ofthe jacket that covers the 

water heater's controls and the. area 

where the heating eleml;lnts, 

thermostatic controls, and electric 

circuits are located. The effects of.these. 

two differences are: (1) the exterior 

surface ar.ea estimates of the DOE's 

analysis are too small; and (2) the tank 

surface area around the heating 

elements, controls, and circuits cannot 

be insulated with foam. Thus, the tank 

surface area has higher standby losses 

than other parts of the tank because it is 

not as well insulated as the rest of the 

storage tank and it also provides several 

thermal leaks where there are 

penetrations of the insula Uon. 

Mr. Daugirda of Rheem Corporation 

stated that the DOE analysis is flawed 

by the use of a 0.5 emissivity and a 

76.6~F temperature difference (150°F 

water temperature and 71.4°F room 

temperature) while the basis of the 

sta11dby loss is an 80°F difference. Mr. 

Daugirda indicated that these flaws 

caus.e a three percent discrepancy due 

to «?missivity .and a 4.3 percent 

discrepancy due to temperature 

differences. This accounts for a 

cumulative 7.3 percent difference from 

the expected. These latter assumptions 

are made based on the outlet and relief 

valve fittings typically being at the top 

of the tank (highest temperature) and 

inlet and drain fittings typically being at 

the bottom of the tank (lowest 

temperature). 

DOE Response: The commenters are 

incorrect in their statement that DOE 

assumed that commercial electric 

storage water heaters are constructed in 

the same manner as residential electric 

models. Data from commercial water 

heater manufacturers and vendors were 

used to establish modeling parameters 

foflhe analysis. DOE is quite aware of 

the extensions of surface area that occur 

on commercial units, such as extensions 

covering the heating elements, controls, 

and electric circuits. According to 

manufacturers literature, these 

extensions vary depending on the unit 

selected. Therefore, it would be difficult, 

time-consuming, and non-productive to 

model every model and type of unit. 

DOE used a modeling approach that 

considered the water heater as a right 

cylinder. The jacket surface area used in 

the calculations was based on the area 

of a cylinder without regard to any 

extensions of that area required to 

accommodate the electrical components. 

DOE believes that this method 

represents the most consistent method 

of dealing with jacket surface area. 

Consideration of the additional area 

covering the electrical components 

would lead to a lpwering of the 

calculated standby loss for an individual 

unit. However. in its. model, DOE has 

accounted for the standby losses 

attributed to fitting, controls, and other 

externalities. 

Various published studies on water 

heaters were reviewed to approximate 

the losses attributable to fittings :md 

controls. [Harris, 1984; Hoskins, 1977; 

Mutch, 1974; Palla, 1979] The 

information available from these reports 

was based on analysis and testing of 

residential water heaters. No data on 

commercial fittings and controls was 

uncovered and none of the commenters 

provided such data. Appropriate 

adjustments were made to adapt the 

information for commercial storage 

water heaters. DOE concluded from this 

analysis that the heat loss from: 

Pressure Relief Valve Fitting=14 Btu/h@ 

72"F &T 

Drain Valve Fjtting=7 Btu/h@72°F AT 

To develop figures for the inlet and 

outlet water line fittings, the assumption 

was made that the losses were 

proportional to the diameter of the 

fittings, and that the outlet (hot) fitting 

would be equivalent to the pressure 

relief valve fitting and the inlet (cold) 

fHting would be equivalent to the drain 

valve fitting. Under these assumptions, 

and considering the relative diameters 

of typical fittings the following loss 

figures were estimated: 

Inlet Fitting=14 Btu/h@72°F .t. T (at assumed 

twice drain valve fitting diameter) 

Outlet Fitting=28 Btu/h@72°F .AT (at 

assumed twice pressure relief valve 

fitting diameter) 

None of the published reports 

provided data on the losses from the 

controls for the electric water heaters. 

The controls are considered to include 

the thermostat and electric heating 

elements along with the associated 

wiring. The NIST test data was used to 

develop a loss figure for the controls. 

The NIST tests on the electric water 

heater modified to eliminate thermal 

shorts yielded an average heat loss rate 

of 294.2 Btu/h. When the NIST unit was 

further modified by wrapping the unit in 

an R-11 insulation blanket and inserting 

an R-11 batt over the electrical 

components the average heat loss rate 

was 237.9 Btuh. The difference between 

the two loss rates was presumably due 

to the jacket loss reduction and the 

reduction in loss from the electrical 

controls. Use of the model would allow 

the determination of the jacket bss 

reduction, leaving the remaining loss as 

attributable to the controls. 
 55FR23842

Using the NIST test data: for the 

modified unit and the.modified unit plus 

· an insulation jacket: · 

NISTMODl(modified unit) average heat . 

loss=Z94.2 Btu/h . · 

NISTh10D2 (modified unit plus R~:l1 

· Batt)=237.9 Btu/h · 

Difference=56.3 Btu/h 

Using the model t<;1 predict the 

difference in jacket heat losses: 

MOD1 (model with the same insulation NIST 

unil)=193.4 Btu/h 

MOD2 (modelwith R-11 insulation blanket 

added)=162.3 Btu/h 

Difference=31.1 Btu/h. 

The difference between the two. NIST 

tests does not reflect any difference in 

the losses from the fittings since no · 

changes were made in this area. Thus, 

the difference in the NIST tests results 

from the difference in the jacket kisses 

plus the difference in the controls losses. 

Since L'ie jacket loss difference is 

presumably accounted for by the model, 

fae remaining difference should be the 

losses associated w~th the controls. 

Difference in NIST tests (294.2-237.9)=56.3 

Btu/h .· . 

Difference in model (193.4:-162.3)=.31.1 Btu/ h . 

Amount attributable to controls lo8ses=25.2 

Btu/h. 

Summarizing the estimated losses for 

the non-jacket areas (fittings and 

controls) after correction to the test 

conditions of 79.95°F .6.: 

Inlet Fitting {14 Btu/h @72 •p ATJ=15.'5 Btu/ h . . 

Outlet Fitting (28 Btu/h@ 72 °F Ji,. T}=31.1 

Btu/h 

Pressure Relief Valve {14 Btu/h@ 72 •p 

AT)= 15.5 Btu/h 

Drain Fitting (7Btu/h@72 °F AT)=7.8 Btu/h 

Controls=25.2 Btu/h 

Total Lo&s.=1)5.1 Btu/h 

To correlate the results of the model 

with the results of the tests, these 

fittirigs and control losses are 

substituted into an equation that 

describes the heat loss: 

Heat Loss=Jacket Loss + Fittings Loss + 

Controls Loss 

From the model for the modification 

#1 condition, the heat loss is 193.4 Btu/ 

h. The corresponding heat loss from the 

NIST test data is 294.2 Btu/h. The 

difference between the two figures is 

100.8 Btu/h. Comparing this number to 

the total lOss from fittings and controls 

indicates that the model and the test 

results show heat loss within 5.7 Btu/h 

of each other, when reasonable 

assumptions for the fittings and controls 

are made. 

The test proced\J.re DOE used for 

electric water heaters (ANSI Standard 

C72:1'."""1972) calls for .<J. test room 

temperature of 73.4 °F ± 5 °F. ±3.~ °F 

and a top-of-tank water temperature of 

150 °F±5 °F. This information is 

provided in the Prelirriin<J.ry Statement of 

Reasons. The equation used in the DOE 

Interim'Standards to calculate standby 

losses includes a term to correct the · 

actual test condition to an 80 °F . 

temperature rise condition. In 

calculating the standby loss rate for a 

given electriC water heater model, as 

subjected to the ANSI Standard G72.1-

1972 test conditions, the computer model 

used the specified room air temperature 

of 73.4 °F, not 71.4 °F as stated in the 

comment, and tank water temperature of. 

150 °F. Then, the standby loss equation 

was used to project the losses that 

would occur with and 80 °F temperature 

rise. Therefore, the standby losses · 

calculated were based on an.SO °F 

temperature difference, not the 76;6 °F 

difference stated in the comment. 

With respect to emissivity levels, DOE 

modeled a range of water heaters at 0.1. 

0.5. and 0.9 emissivity. The data 

reported in Figure 3 indicated there is no 

appreciable difference between 

emissivity levels. 

BIWNG CODE 6450-01-U 
 55FR23842

Federal Register: I Vot p5, No .. 113 /Tuesday, Ju,ne 12, 1990 /Rules and Regillations • ; i • 1 23855 ' ! ' • 

ELECTRIC VI ATER HEATER STANDBY LOSSES 

50 Gallon Electric Model 

2..1.--....-~~-.-~-r-~-r-~-.----r~-.-~-.-~..,.-~r----..~-.-' 

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7 .0 

lnsulaiion Thickness (in.) 

---- Fiberg!ass-.5 -+- Foam-.5 Emis ~ riberglass-.9 -s- Foam-.9 Emis 

·---- ·-----·----

Figure 3 - Sensitivity to ssivity 
 55FR23842

23856 Federal Regist~~ l VoL 5~, No. 113 l TuE)sday, June .12, 1.990 / Rules and Regulations 

b. Manufacturer Test Data vs. DOE 

Calculations. State Industries, Inc. and 

Bradford-White Corporation stated that 

they had tested water heaters of 

approximately 50-gallon capacity. They 

and GAMA refer to these tests and 

concluded that the DOE model is invalid 

because the DOE predictions of standby 

loss for that size unit are far less than 

their test results. Mr. Collins of State 

Industries, Inc., concluded that DOE had 

used too low a jacket emissivity, and 

did not take into account other losses 

. such as those that occur through fittings. 

values, and clean-out op,enings. GAtl.1A 

and SI commented that it was necessary 

to use two inches of foam insulation 

around the tank (except around the 

thermostat/heating ~lement/ control 

area where two inches of fiber glass are 

used) to meet the current 4 W /ft 2 

criterion, as opposed to the DOE 

calculation of two inches of fiberglass. 

GAMA further commented that DOE 

had neither used empirical data nor 

validated its model against empirical 

data. GAMA cited ASHRAE Research. 

Project 502 where such a comparison 

had been made using .a simple model 

and blanket insulation. They further 

cited this project as concluding that 

insulation exceeding R-50 wouklbe 

needed to achieve a standby loss of i.9 

W/ft 2 • 

DOE Response: No supporting unit 

description, test description, or test data 

were provided by the manufacturers or 

by CAM.I\. upon which DOE could 

evaluate the comments relative to the 

tested units. 

DOE commissioned tests at NIST on a 

unit similar to the capacity of the units 

which the manufacturers stated they 

had tested [NIST Letter Report, 1990]. 

The results of standby tests showed the 

unit as shipped performed very poorly 

relative to published claims: Simple 

correction of major the.rmal bridging 

resulted in a 28 percent heat loss 

reduction. Data from the tests of the 

modified unit and from the unit with an 

insulation blanket added were used in a 

comparison with the predictions of the 

DOE model. The model was able to 

predict the results within a factor of 

±15 percent. 

A Bradford-White commercial electric 

water heater, model M-I-50-12-35F115(S/N GC013836), was purchased from 

a local distributor for evaluation, The 

tank had an advertised (nominal) 

capacity of 50 gallons. AH tests were 

conducted in accordance with DOD's 

Energy Conservation Progam for 

Consumer Products, 10 CFR Part 430 

(Janu~ry 1, 1985) in lieu of the test 

procedure specified within the Energy 

Pcrfor~ance Standards for Commercial 

and Multi-Family High Rise Residential 

Buildings, ANSI Standard C72.1. The 

cited ANSI Standard has been 

withdrawn by ANSI. 

Measured standby losses for the 

unmodified electric water heater were 

120.3 watts per hour or 5.67 W/ft2 of 

tank surface area. This exceeds 

compliance with ANSI/ ASHRAE/IES 

Standard 90A-1980's criterion of 4 W / ft 2 

that was in place until December 1989. 

During the initial tests, the bottom of 

the jacket on the water heater and the 

metal enclosure housing the heating 

elements were identified as sources of 

excessive heat loss using an infrared 

scanner. The tank had severely 

compressed the fiberglass insulation on 

which it rested so as to be almost 

ineffective. This permitted the heat to 

travel from the tank to the sheet metal 

bottom jacket material and hence to 

outside edge of the jacket which was hot 

to the touch. The bottom of the tank was 

removed and void spaces between the 

jacket and storage vessel filled with 

foam. The tank was placed on a two 

inch piece of extruded polystyrene 

(R-10). 

The enclosure, which permits access 

to the heating elements, was altered by 

removing a portion which was in contact 

with the storage tank The unaltered 

enclosure provided a'direct path for heat 

flow from the storage vessel to the 

surrounding ambient air. Approximately 

hvo inches of fiberglass insulation was 

installed in the area previously occupied 

by the removed metal. Measured 

standby losses fpr this modified tank 

were 86.2 watts per hour or 4.00 W /ft2 of 

tank surface area, thereby bringing it · 

close to compliance with ANSI/ 

ASHRAE/IES Standard 90A-1980. This 

represents the 28 percent reduction in 

the heat loss from the storage tank. 

The tank, modified as described 

above:was wrapped with an R-11 foilfaced fiberglass insulation blanket.The' 

measured emissivity of the foil is O.o3. 

The blanket was installed over the · 

entire exterior of the jacket with the 

exception of the bottom surface of the 

tank. A foil-faced R-11 batt of fiberglass 

insulation was installed in the 

enclosures that house the heating 

elements and fuses. Measured standby 

losses for this configuration were 69.7 

watts per hour or 3.29 W /ft 2 of tank 

surface area, and were 42 percent less 

than the losses measured for the 

unmodified electric water heater. -

Based on the preliminary analysis 

conducted for the Preliminary · 

Statement, 50-gallon electric water 

heaters were shown to comply with the 

ASHRAE Standard 90A-1980 4 W / f1 2 . 

criterion with approximately 1.5 inches 

of fiberglass insulation. A 

reconsiderntion of that analysis, which 

includes components of heat loss for 

fittings and controls, indicates that 

approximately 1.5 inches of form would 

be required to reach 4 W /ft 2 • 

The computer simulation was 

designed to assess jacket losses from 

water heaters under steady-state 

conditions. When the results of the 

computer model are added to published 

data on fitting losses. the resulting total 

standby loss concurs with test data 

supplied by NIST. 

c. Tank Surface vs. Jacket Surf ace. 

Four comments questioned whether the 

insulation requirements of the DOE 

standby loss criteria pertain to the tank 

surface or jacket surface of an electric 

water heater. Mr. Daugirda of Rheem 

Corporation stated that many more 

commercial units covered by the DOE 

standards could meet the water heater 

standby loss criteria if the tank surface 

is used to determine the f.9 W /ft 2 

maximum standby loss. However, if 

jacket surface area is used, he said, the 

criteria remain infeasible. Mr. Daugirda 

maintained that this should be reflected 

in revised DOE standards. He suggested 

that the standby loss requirement 

should. be changed to read as follows: 

SL<25 W + 2.6. W /ft 2 of tank surface 

area. This change is reques_ted for water 

heaters having volumes up to 120 

gallons. 

GAMA also submitted data to support 

its assertion that DOE remain consistent 

with the criteria used for the last fifteen 

years, and should specify that its 

standby loss requirement is to be based 

on the surface area of the tank. 

Mr. Jim Hildenbrand of ASHRAE .. 

request that DOE change itscrHeria to 

be consistent with the standby loss 

criteria in the recently issued ASHRAE/ • 

IES Standard 90.1-1989 whichis 

expressed in W /ft 2 of tank surface area. · 

DOE Response: DOE agrees with the 

comments that DOE should not set its 

standby loss criterion for electric 

storage water heaters in terms of jacket 

surface area. DOE believes that it is -

likely that the jacket area of different 

manufacturers will vary between water 

heaters of the same capacity and input 

energy, depending on the aspect ratio of 

the tank, the insulation used, and 

varying design and manufacturing 

needs. DOE further believes that the 

jacket area of a unit should not include 

the surface area of the box containing 

wiring, controls and thermostats, which 

project from the side of many water 

heaters; and that it would be 

unnecessarily complex to express this 

concept in a definition to covE;?r those 

and similar conditions. 
 55FR23842

Feder~l R~gister / Vol. 55, No. :113 / ··Tues:day; ·J~ne 12, 1990 I Rule~ and Regulations 23857 

"noE also evaluated expressing the 

criteria in terms of tank surface area. 

The tar~ of many of the units are not 

simple right cylinders. They have a 

concave bottom and convex top. This 

raises the question as to whether to 

calculate the area of the tank as a right 

cylinder or to refine that calculation to 

account for the deformed top and 

bottom. Furthermore, the dimensions of 

the tank are not generally provided in 

the product literature of the 

manufacturer. Fabrication drawings 

would be the only consistent source of 

tank dimensions. In addition, it is 

slightly more difficult to calculate the 

a1eas of the convex and concave 

surfaces. Therefore, DOE concludes that 

it is more appropriate to express the 

criteria in terms of tank surface area 

than in terms of jacket surface area. As 

s:.Jch, the criteria announced today are 

expressed in terms of tank surface area. 

E. Com111enta on Gas Storage l-llater 

Heaters 

1. Construction Characteristics 

DOE received comments from the 

three water heater manufacturers and 

GAMA that implied that the physical 

dlmensions used in modeling 

commercial gas storage water heaters 

were incorrect. The comments indicated 

that DOE's assumption of a single large 

diameter flue tube through the center of 

a water heater tank results in undcrcalculating the uninsulated heat 

exchange area for that loss, and 

incorrectly calculating actual heal loss 

coefficients. They further stated the 

assumption of a single flue tube also 

leads to the incorrect eupposition that a 

flue damper located on the end of the 

flue tube and in the closed position 

effectively seals the flue tube. 

These comments indicated that if 

DOE's analysis had used the practical 

design construction necessary for the 

heat inputs required by the water heater 

market. it would have used a multifhrn 

construction, typically six or seven 

flues. The multiple flue tubes are much 

smaller in di;imeter than in the DOE 

model and are equipped with flue 

baffles. They have a different heat loss 

coefficient from that of a large diameter 

unbaffled flue tube. For instance, two, 3-

inch diameter flue tubes have the same 

surface area as a single, 6-inch diameter 

flue tube, but each 3-inch tube only has 

one-fourt.11 the volume of Llie 6-!nch tube. · 

This diameter-to-volume ratio affects 

the flow of heat from the flue tube wan 

to the air and the resultant standby heat 

loss. Multiple flues require the use of a 

flue collector box located above the 

tank and before the flue outlet of the 

water heater. The flue damper is 

installed on this flue outlet. The flue 

collector box essentially covers the 

entire top of the storage !ank and is 

there to four inches high. Tbe top 

insulation of the water heater is located 

between the flue collector box and the 

top of the water heater jacket. The 

surface area of this box becomes an 

additional area of standby loss on the 

1Nater heater. 

DOE Response: His clear that there is 

a misunderstanding of the assumptions 

DOE used in its modeling approach. The 

assumption of a single flue was made to 

develop an estimate of the increase in 

tank dimensions to accommodate the 

volume of water required. The model d;J 

not attempt to account for the detailed 

heat transfer from internal flue passages 

to the water. Instead the model assumed 

a uniform water temperature a::i 

indicated in the Technical Support 

Document. For the purpose of modeling 

jacket heat loss, the difference between 

single flues and multiple flues is not 

significant. 

The commenters suggested thal the 

assumption of a single flue versus 

multiple flues results in some errors in 

estab1ishing the effect of flue dampers. 

The fact that the flue damper is located 

within the collector box and covers the 

multiple internal flues does not 

necessarily result in different 

performance from a single flue with a 

damper at the flue exit. The intent of the 

flue damper is to retain the hot flue 

gases within the flue rather than 

allowing them to escape up the flue. The 

location of the flue damper is immaterial 

if the effect of its location does not 

change. 

2. Jacket Heat Loss 

State Industries, Inc., Bradford-White 

Corporation, and GAMA argued th.at 

DOE erroneously assumed that using 

flue·dampers and electric igniticn 

devices (IIDs) would eliminate most of 

the tank heat losses other than those 

attributable to jacket losses. They 

pointed out that DOE calculated energy 

savings based on jacket losses of 70 

percent to 90 percent of the total losses, 

and contended that with the addition of 

flue dampers and Ills, jacket iosses are 

between 40 percent and 50 percent of 

the total standby losses. Nearly one-half 

to 60 percent of the losses are 

unaffected by increasing the thickness 

of insulation. GAMA referred to, but did 

not identify, two manufacturers who 

apparently conducted tests on their own 

units to prove this point, and partial test 

information was included in their 

comments. 

Another criticism of the assumptions 

was that DOE made no attempt to 

measure the percentage loss attributable 

to jacket loss. It stated that DOE's 

analysis assumes that models currently 

equipped with flue dampers and IIDs 

have jacket losses that account for 70 

percent or more of the total standby 

loss. However, .GAMA and Stale 

Industries indicated that in no case did 

the. analysis measure the percentage of 

loss attributable to jacket loss on such 

water heaters. GAMA and State 

Industries indicated that manufacturers' 

experience and knowledge gained in 

improving the efficiency of commercial 

storage water heaters show that the 

losses through the flue still account for 

50 percent or more of the total 

loss. GAMA, Bradford-White 

Corporation, and State Industries 

contended that although effective in 

diminishing a major portion of the flue 

gas loss, flue damp.ers do not eliminate 

that loss entirely. Rather, the s!eel 

damper that obstructs the hot flue gas 

will be warmed and conduct heat away 

from the system. In the open 

the damper is subject to thermal 

expansion due to continual exposure to 

the high temperature flue gases exiting 

the water heater. When the burner shuts 

off and the damper closes, it will cooi 

down. As it cools down, the damper will 

contract slightly. Thus, GA.l'v!A and State 

Industries maintained, even putting 

aside the realities of production and 

fabrication tolerances, a damper that 

might seal tight when first closed, might 

not maintain that seal. 

Dr. Goldstein of NRDC commented 

that flue dampers were necessary to 

meet the DOE standards, and promoted 

the idea of using flue dampers in 

conjunction with additional insulation 

on commercial gas water heaters. 

DOE Response: Although experience 

and knowledge, and some testing, wer·e 

given as reasons for the negative 

comments on the use of flue dampers 

and IIDs, no -substantive information 

was provided. To more fully respond to 

those who commented, it would have 

been necessary for DOE to receive data 

on the characteristics of the units tesled 

by the manufacturers, particularly on 

the flue damper used and the jacket and 

flue collector box insulation. Without 

such data it is not really possible to 

evaluate this statement fully. 

DOE believes that those who 

commented misunderstood the DOE 

analysis. DOE assumed, for the purpose 

of its analysis, that after a flue damper 

and electronic ignition device were 

added to a commercial gas storage 

water healer, 70 percent of the 

remaining heat los3 would be through 

the jacket. This presumes that 30 

percent of the loss remains through flue 

and pilot losses and that the standby 
 55FR23842

Federal Register / Vol. 55, 'No. i::l'3. / TU:esday,'Jilnec12, 1990 /Rules and R~gulations 

loss criteria cannot be attained simply 

by adding insulation. 

DOE does not consider acceptable the 

contention of those who commented that 

50 percent or more of the loss comes 

through the flue despite the presence of 

a flue damper. First, while it is 

understandable that flue dampers are 

not 100 percent efficient, it is also 

-conceivable that better design and 

production and the more predominant 

use of electronic flue dampers can 

rectify much of the residual heat loss. 

Second, the DOE test on a commercial 

gas water heater at NIST indicates that 

total he,at loss without a flue damper 

during the cool down mode of the test 

procedure is approximtely 50 percent 

during the first 24 hours. With the flue 

damper, the percentage heat loss during 

a similar 24-hour period was only about 

30 percent. See Figures 4 and 5. These 

figures were based on the total standby 

losses minus those through the jacket, 

fittings, gas valve, and piping losses. 

While not confirming the percentage 

thermal resistance provided by a flue 

damper, the test was illustrative of the 

effect flue dampers can have. 

In regard to Dr. Goldstein's comment, 

DOE agrees that flue dampers are an 

integral part of water heater energy 

conservation and that they, along with 

IIDs, should be added to units that 

cannot now meet the DOE criteria with 

insulation only. 

BIU.il>lG COO£ 64!;G-OH\l 
 55FR23842

Federal Register/ .Vol. 55, No. 113 I Tuesday, Juae 12, 1990 /Rules and Regulations 23359 

GAS WATER HEATER WITHOUT FLUE DAMPER 

COOL DJWN TEST - NIST TEST RESULTS 

n 

I-" 

as 

ro 

::;; 

<t: 0.7 l 

;.'. 

~ ;- 0.6 

'::I 

::: 

I::: 0.5 

:::: 

v 

' 0.4 

~' w 

m 0 3 

~ I 

~ 0.2 <i 

Iv 

0 1 

O' d l 2 I 4 J !fT I 10 12 I 11 16 18 20 2'2 24 I 26 28 I 30 3?_ 34 " 1 9 11 13 15 1 f i 21 23 2's' 2 29 31 33 3 

ELAPSED T lf~E ( HOIJP.S)- N I ST TEST RESULTS 

Figure 4--NIST Gas Water Heater Cool-Down Test v/out Flue 
 55FR23842

. 23660 Federal Register J Vol; 55, No. 113 /Tuesday, June 12, i990 / Rules and Regulations . 

GAS HEATER WITH TOTAL FLUE RESTRICTION 

COOL DOWN TEST - NIST TEST RESULTS 

0.9 

" " I- o a z 

UJ 

a:i 

::i 

<( 0.7 I 

~ 

~ I- 0.6 

':f 

~ 

I- 0.5 z 

u 

' 0.4 t:' 

z 

liJ 

ID 0.3 

~ I 

~ 0.2 

~ u 

0 1 

0 

Figure 5 - NIST Gas Water Heater Cool-Down Test w/ Flue Damper 

Ellll.ING CODE 6450-01-C 
 55FR23842

Federal Register I Vol. 55, No. 113 /Tuesda:it. June 12; 1990 I Rules and Regtilations 

3. Insulation. 

DOE received three comments 

concerning insulation. Mr. West of 

Bradford-White Corporation indicated 

that the heat exchange surface needed 

for the efficient transfer of heat for the 

combustion process, the bottom area of 

the tank, cannot be insulated in a 

practical manner, He stated that DOE 

apparently failed to account for this in 

the analysis. Since the need to transfer 

heat exists during combustion, a similar 

transfer of heat occurs during the 

periods of standby operation. At this 

time, heat flow begins to reverse in its 

direction, therefore, heat loss emanates 

from this needed uninsulated area. The 

water heater bottom area is efficient in 

transferring combustion heat but it also 

adds to the heat loss during standby 

periods. 

Mr. Stanonik of GAMA stated that 

DOE's analysis underestimates the 

standby loss through the top of the 

storage tank because it places the 

insulation on top of the water heater. 

The insulation on the top of the water 

heater actually is on the top of the flue 

collector box. not on top of the storage 

tank. With an air space of three to four 

inches between the top of the tank and 

the top of the water heater, there will be 

an appreciably larger loss through the 

top of the tank than predicted by the 

DOE analysis. 

Finally, GAAIA commented that the 

DOE standby loss criteria contradicts 

several of the studies and reports 

referenced by DOE. Mr. Stanonik 

suggested that at some R-values of 

insulation there is no significant 

potential for saving energy by further 

increasing the insulation levels. The 

1982 "Consumer Products Efficiency 

Standards Engineering Analysis 

Document" prepared by Arthur D. Little, 

Co. for DOE and cited as a reference 

source in the development of the 

standby loss requirements for electric 

residential water heaters states that the 

point at which further insulation is not 

b1meficial is an R-value of about 14. For 

residential gas water heaters, the report 

indicates that the same point is an Rvalue of about 16. These levels are 

consistent with information in a 1977 

study by Oak Ridge National Laboratory 

entitled, "Energy and Cost Analysis of 

Residential Water Healers" and the 

1979 National Bureau of Standards 

Report entitled. "Evaluation of Energy 

Conserving Modifications for Water 

Heaters." The DOE analysis suggests 

that this critical point is an R-value of 21 

for commercial electric water heaters 

and an R-value of 18 to 21 for 

commercial gas water heaters, 

de.pending on what percentage of 

standby loss is .attributed to jacket 

losses. The DOE analysis suggests a 

larger.optimal thickness of insulation 

than the other studies, even though DOE 

used these studies to establish its 

standby loss criteria. 

DOE Response: DOE understands that 

the bottom surface of a gas water heater 

is uninsulated. In its analysis, DOE 

included any heat losses from this 

surface in the category of other losses. 

The other loss category was used to 

include all areas of essentially 

uncontrollable losses such as the bottom 

surface and the flue losses. No 

pubhshed data was available on the 

amount of heat losses attributable to the 

bottom surface of gas water heaters 

which would allow for treating this loss 

separately. In addition. manufacturers' 

data indica les the configuration of tl1e 

bottom surface of the water heaters as 

well as the burner units varies among 

different manufacturers. 

While it is true that during standby 

conditions heat will tend to flow from 

the warmer water out through the 

bottom surface to the surrounding air, 

the actual heat loss will be less than 

suggested due to the natural tendency 

for heat to rise. In addition, test data has 

shown that the temperature of the water 

in the bottom of the tank will be less 

than the temperature at the top of the 

tank. As a consequence, si.r1ce the heat 

loss is a function of the temperature 

difference between the water and 

surrounding air temperature, heat loss 

through the bottom of the tank ·will be 

lower than through other areas of the 

tank surfaces due to the lower 

temperature differences. 

The commentor indicated tJ1at 

insulation on the top of commercial 

water heaters is placed on top of the 

flue collector box and not on top of the 

storage tank as assumed in the D0E 

analysis. For the Bradford-White 

commerical gas unit tested by NIST, the 

insulation is located on top ofthe 

storage tank. DOE believes that the 

location of the insulation assumed for 

the modeling is appropriate and 

consistent with current construction 

practices. 

The DOE standby loss criteria does 

not contradict the other studies and 

reports referenced by Mr. Stanonik. The 

analysis performed to support the 

current criteria was based on current 

costs for energy, labor and materials. 

The previous studies were conducted a_t 

least eight years ago, one of them beL.1g 

13 years ago. Costs have changed since 

Hie publication of those reports. and the 

change in costs is reflected in the 

current analysis. Additionally, the 

referenced studies dealt with residential 

versus commercial water heaters. DOE 

made adjustments in its analysis ta _ 

account for the differences in size, 

construction techniques and operating 

conditions between commercial and 

residential units. In fact, results from 

some of the referenced reports were 

used in correlating the DOE model to the 

NIST test data. 

4. Surface Emissivity 

Comments from Rheem, State 

Industries, and GAMA each indicated 

that DOE underestimated standby 

losses in commerical storage water 

heaters by using an emissivity factor of 

0.5 rather than 0.9. Mr. Daugirda of 

Rheem Corporation stated that this 

causes a three percent discrepancy. 

According to the Gas Engineers 

Handbook (The Industrial Press, 1965}, 

the surface emissivity of various paints 

of different colors and types is 0.9 or 

higher. AH the jackets of commercial 

storage gas water heaters are painted. 

Therefore, the 0.9 emissivity value 

should have been used in the analysis. 

The direct result of utilizing a higher 

number would be increased standby 

heat loss. 

DOE Response: The emissivity values 

chosen for the DOE model were taken 

from a widely accepted heat transfer 

text book with similar data to the 1955 

edition of the Gas Engineers Handbook 

[Heat Tran sf er, an Alan Chapman 

Engineering Text]. The value for a 

painted surface was in the 0.9 range. 

However, at the time of the modeling, 

DOE was aware that some units are 

offered with stainless steel jackets and 

it was assumed that not all the surfaces 

were painted. The value for a stsinless 

steel surface was 0.1, so an approximate 

average of these two was calculated to 

arrive at the 0.5 emissivity factor used in 

the DOE analysis. 

Using an emissivity of 0.5 rather than 

an emissivity of 0.9 results in an 

extremely small difference in the 

calculated standby loss. The computer 

analysis was run at three separate 

levels--0.5, 0.7, and 0.9-and DOE found 

little appreciable difference in standby 

loss rates at any level of added 

insulation. For all subsequent analysis, 

, DOE used 0.9 surface emissivity. See 

Figure 3. 

5. Water Heater Fittings 

Bradford-White Corporation and 

GAMA indicated that water heater 

fitting(s) losses are distinctly different 

from the jacket and flue losses and need 

to be considered in any analysis. The 

comments maintained that DOE's 

analysis underestimates standby losses 

becal!se it does not consider the. standby 
 55FR23842

23862 ·,Federal Register/ Vol. 55; No. 113 I Tuesday; June' 12, 1990 I Rules and Regulations 

losses that occur throt1"gh such fittings~ 

The losses from thermal leaks created 

by fittings that connect through the 

insulation to the tank contribute to 

standby loss but are not affected by the 

addition of insulation. The comments 

cited an Arthur D. Little, Co. report 

entitled, "Study of Energy Saving. · 

Options for Refrigerators and Water 

Heaters," published in 1976, that 

determined that the fitting losses are 

about 85 Btu/h in a residential gas water 

heater and about 110 Btu/h on a. 

residential electric water heater. 

Considering that the fittings on 

commercial storage. tanks wm be larger 

and that such tanks also acid a Clean-out 

valve, the fitting losses on cmnfnereial · 

storage water heaters will at least be 

comparable to residential units~ These 

fitting losses represent over four percent 

of the 090 percent allowable fosses" of 

1932.26 Btu in.DOE's analysis for the 

100-gallon gas model and almost 20 

percent of the "90 percE!nt allowable 

losses" of 539 Btu for the 120-gallon 

electric model. 

DOE Response: In. the initial 

modeling, DOE used an aggregate 

numberfor fitting losses'. Subsequently? 

further information wail identified and 

used in the latest modeling runs. For .. 

electric water heaters; Hie total standby 

loss for fittings was 100.85 B,tu/h. The 

number for gas water heaters is 

approximately 75 percent of the electric 

fittings losses because controls are not 

included. Figures 1and2 illustrate the 

avenues of standby loss for electric and 

gas water heaters. Subsection D of this 

Section contains additional information 

relevant to this topic. 

6. Heat Traps 

DOE received one comment from 

GAlvlA concerning heat traps. Mr. 

Stanonik stated that there is a conflict 

between the DOE analysis and an 

earlier DOE document~"1982 DOE 

Engineering Analysis Document". In the 

papers submitted in response to the 

lawsuit filed by GAlvlA, DOE stated that 

the use of heat traps were not factored 

into the establishment of the standby 

loss requirement. Mr. Stanonik 

contended that the use of lhe 1982 DOE 

document as a primary reference 

contradicts this statement. Furthermore, 

~~·"~ .. ~ .... ,, to Mr. Stanonik, at a February 

11, 1990, of the ASHR.l\E SSPC 

90R Service Waler Heating 

Subcommittee, ASHRAE factored in the 

benefits of heat traps even though 

neither the referenced test procedures 

nor the text of the ASHRAE 

specifications allow for a credit for heat 

traps in the determination of a water 

heater's standby loss. 

. DOE Response: In setting the standby 

·loss criteria, DOE has not assumed tha·t 

any or all water heaters will come with 

integral heat traps. Heat traps that are 

integral to the unit, which are more 

efficient than the heat traps required of 

the test procedure, would receive credit 

from the gas water heater test 

procedure. GAMA thus misconstrues or 

misrepresents DOE's reference ofthe 

1982 DOE document. DOE has included 

heat traps in its standby .loss 

calculations per the requirements ofthe 

test procedures and the January 30, 1989, 

DOE Interim Standards. In the ANSI gas 

water heater test procedure, heat traps 

on both the inlet and outlet ports are to 

be installed if not already present before 

testing. In addition all inlet and outlet 

piping iμcluding heat traps (or a length 

of four feet from the tank is insulated to 

a mii:liinum R-4. A temperature and 

pressure relief valve is also to be 

installed if not already and insulated to 

R-4. 

The ANSI electric water heater test 

method does not require heat traps and 

. insulation on temperature and pressure 

relief valves, Association insulation, 

including pipe, are not required to be 

installed or added prior to testing. 

The 'DOE Interim Standards require 

heat traps to be installed on storage 

w.ater heaters when not supplied as part 

of the unit. Circulating systems do not 

require heat traps. The standards also 

require piping on storage water heaters 

to be insulated to R-4 for the first eight 

feet from the tank, this would include 

traps, for inlet and outlet connection 

sizes up to two inches. This will include 

most units up to the 300-gallon range. 

Insulation with a thermal resistance of 

R-6 is required for connections above 

two inches. The standards do not 

specifically require insulation on relief 

valves. 

The primary difference between the 

test procedures and the DOE standards 

is the additional four feet of insulated 

inlet and outlet piping. In the case of an 

operating tank. with hot water being 

drawn from the tank, the entire pipe will 

be full of hot water and an additional 

four feet of insulated pipe out of tens 

and hundreds of feet of total will 

have very minimal effect. 

"""""''" situations, the heat ~~•me•~· heat transfer 

to the 

return of added insulation, of 

the additional four feet beyond the tank 

during standby periods wm also have 

little effect The test method also credits 

insulation on relief valves, which is not 

, cLmu. cu by the standard. 

DOE has included these requirements 

in developing the model that estimates 

water heater requirements to meet the 

DOE standards. Manufacturers should 

already be aware of these requirements 

for use in their own testing. 

DOE rejects the assertion that neither 

the test procedures nor the ASHRAE/ 

IES Standard 90.1-1989 requires heat 

traps; in fact, they both incorporated 

heat traps. The insulation on the trap 

and pipe in the test method is equivalent 

to that required by the standards, hence, 

a more effective internal heat trap may 

well reduce additional standby heat loss 

not addressed by the R-4 pipe insulation 

required in the test procedure. 

It should be noted that while DOE has 

found it beneficial to listen to and 

participate in the deliberations of 

ASHRAE SSPC 90R, DOE has 

independently considered the . 

information received and reached its 

own conclusions. 

7. Water Heater Recovery Efficiency 

DOE received one comment, from 

Rheem Corporation, indicating that the 

use of 75 percent recovery efficiency is 

misleading when applied to the recovery 

of standby losses. Mr. Dauffirda of 

Rheem stated that the thermal efficiency 

of commercial gas storage water heaters 

is determined under steady-state 

conditions and that during the course of 

the standby loss determination, the 

recovery efficiency for the short 

recovery cycles are in the 60 percent 

range. Therefore, according to Mr. 

Daugirda, the recovery efficiency is 

variable, depending on the mass of the 

water heater in addition to the stored 

water that is to be heated. 

DOE Response: In the DOE model,· 

recovery efficiency has been assumed to 

be equivalent to the thermal efficiency 

of the water heater. Rheem states 

without supporting information that the 

recovery efficiency is much lower than 

that. For the gas water heater tested by 

NIST, the recovery efficiency was 72 

percent, or very close to the 75 percent 

efficiency rating of the unit tested. 

8. Measured Data 

Bradford-White Corporation 

maintained that the DOE analyses were 

as shown manufacturer tests 

in response to DOE's 

""""u''"'CJ' Statement 

In an to verify the DOE 

conclusions, Bradford-White 

Cornoration constructed and tested a . gas i•1rater heater nn;tntvr1"' 

, -~··~.-·~~ Btu/h with 

and HD, and two inches 

external i;:isulation. With the additional 

insulation, a total R-value of 10.3 was 

achieved. The test results for this unit 

indicate a 2.02 percent standby loss per 
 55FR23842

hour. Mr. West of Bradford-White 

contended, therefore. that the 

achievement of a 1.63 percent per hour r 

standby foss rate is not possible under 

the conditions specified in the DOE 

analysis. In addition. the 2.02 percent 

vaiue can only be achieved under 

laboratory test conditions because in 

real use situations ssveraI water.heater 

externalities, such as the controls and 

drain value fittings cannot be covered 

by the insulation wrap. 

DOE Response: The commenter 

provided no data to substantiate his 

argument that test data indicated that 

available gas units could not be brought 

into compliance. Test data provided by 

t:11e California Energy· Corn:mission 

indicates that several gas water heaters 

that are commerciaHy available do 

comply with the current standby loss 

criteria. The test data provided by NIST 

indicates that when properly insulated 

the test unit actually exceeds the 

standby loss. criteria. 

9. Cost Benefit Analysis 

a. Modeling andAssumptjons. · 

Comments were received from State 

Industries, Rheem, and GM1Athat 

criticized DOE's cost-benefit analysis 

model and the assumptions used in 

developing the model. These comments 

argued that the energy calculations,.the 

cost data, and payback periods were 

wrong. J'hey indicated that the cost of 

adding insulation, including labor, 

retooling costs, and profit, was based on 

residential storage water heaters and 

not commercial water heaters. Finally, 

they asserted that DOE did not prepare 

a· complete cost-benefit analysis. They 

pointed. out that DOE did recognize · 

current models of gas storage water 

heaters. all low input models, that. 

comply with existing standards and will 

comply wit.Ii the DOE standards if flue 

dampers and llDs are added .. They 

maintained. however, thal DOE's 

analysis does not reflect the true costs 

of adding a flue damper Ol' an IID. 

It was suggested that OOE could have 

conducted a more detailed analysis if it 

had surveyed suppliers of commercial 

water heaters to obtain cost differences 

in comparable models, with and without 

flue dampers and IIDs. GA~LJ\ pointed 

out that DOE would have discovered 

that the addition of the flue damper and 

IID raises the price of the water heater 

by $500.00 or more. Comparing this cost 

to the benefit calculated by DOE. the. 

flue damper and I!D option would have 

a simple payback of almost 14 years 

under the most realistic conditions of 

usage. Therefore, GAMA concluded that 

DOE's decision to establish a standby 

loss aUerfa to require flue dampers and 

IIDs on non-equipped models is not 

economicaily justified. 

DOE Response: In attempting to 

establish the costs for adding insulation. 

flue dampers, and IIDs, DOE sought 

information from the industry to 

establish representativa costs. Various 

manufacturers were contacted to secure 

cost information. Unfortunately the 

commenters did not supply information 

to substantiate their claims that the 

DOE information developed as part of 

this process was incorrect. Costs for 

retooling and profit were not separately 

included in the DOE analysis, and thus 

cannot be presumed to be incor:recl All 

of the data collected by DOE was 

solicited based on current reta.il cosf,3 

for commercial rather than residential 

units. 

b. Cost/Benefit of Flue Dampel's and 

I!Ds. DOE received three comments 

from Rheem Corporation, BradfordWhlte Corporation, and GAM.>\ 

concerning the required addition of flue 

dampers and IIDs to many models 

currently on the market if these models 

are to meet the DOE standby loss· 

criteria. The DOE analysis assumes that 

the benefit of the flue dmnper and IID 

occurs 24-hours per day. The comments 

argued that it should be obvious to DOE 

that when a water heater burner is 

operating, .the flue damper is not dosed. 

They maintained that a generous 

estimate for the standby period is 20 

hours. Based on 24-hour per day 

standby, DOE estimated annual savings 

of $30,41. Using the 20-hour per day 

figure, the comments estimated annual 

savings of$21.29. They alw argued that 

the true cost of the benefit was not 

analyzed. Mr. West of Bradford-White . 

indicated that the addition of a flue 

damper and IID increases the water 

heater cost by $594.000 to the consumer. 

At $21.29 per year in energy savings; the 

payback period would be 28 years 

instead of the DOE estimate of three 

years. 

DOE Response: Assuming that the 

units are not firing for 20 hours dai!y, a 

reduction of hours from 24 to 20 results 

in an approximate 17 percent change in 

time for potential savings. Adjusting for 

a normal work week, the :reduction is 

about 8 percent. The commentors 

contend the change i:n savings would be 

on the order of 30 percent which is 

inconsistent with the change in 

operating hours. DOE believes, given 

these assumptions, that its cost-benefit 

analysis remains valid. 

With the exception of several of the 

smaller units, DOE assumes that flue 

dampers and lIDs wm be required on aU 

gas water heaters to meet current as 

weU as future national standards. Thus 

the added cost of these devices is 

vfrtually nil since they would have been 

required anyway in the absence of the 

DOE standard. 

When setting new, more stringent 

standards criteria, it is logical to assillne 

that a few model offerings that 

previously only marginally met the 

former criteria may not be cost 

effectively modified to meet the new 

criteria. DOE has not analvzed the 

variety of engineering strategies 

heretofore used by manufacturers to 

obtain minimal compliance with the 

prior standards, but which would not be 

necessary should more effective 

measures be incorporated to meet the 

new criteria. For example, if baffle 

dampers should be replaced by 

electronic dampers for that purpose. 

Hence, DOE believes its cost benefit 

analysis is quite reasonable. 

Where it is marginally effective to' 

modify such units they may be offered 

as options or discontinued in favor.of 

other options.' If discontinued, designers 

will select other alternatives for the 

market, either rounding up or down 

factors used in their sizing assumptions. 

For example, a "residential" sized and 

fired unit may be selected. 

c. Payback Period. GAMA 

commented Hmt DOE should not use 

any payback period longer than five 

years. In the Preliminary Statement, 

DOE identified a three- to five-year 

payback as acceptable in the nonfederaI sector and seven to ten years as 

acceptable payback for federal agencies. 

GAMA commented that if any payback 

in excess of five.years is used, the more 

expensive unit may never pay back 

because the unit may fail in the interim. 

A typical commercial storage water 

heater is warranted for three.years. Two 

major factors affect water heater 

lifetime-the amount of water required . 

and the quality of that water. These 

factors vary greatly in commercial 

applications, and likewise so does the 

range of service life of commercial 

storage water heate.rs-less than three 

years to more than ten years. A 

representative, typical service life is five 

years. 

DOE Response: The typical payback 

periods cited in the DOE Preliminary 

Statement stem from the factors 

normally used by DOE to assess energy 

conservation measures in buildings. The 

Federal government, being the ovvner/ 

operator of its buildings, generally 

specifies materials and equipment built 

to last a great deal longer than in some 

parts of the non-federal sector. 

Therefore. it is willing to invest in 

energy conservation measures that have 

a longer payback if the measures are to 
 55FR23842

Federiil Register / Vol. · 55, ··No; 113 f Tuesday', June 12. t990 ·· / Rules and ·Regulations 

· be life"cycle cost-effective •. Ail 

purchases for federal government 

. buildings, cespecialiy for energy· 

conservation, must be justified as lifocycle cost-effective using a methodology 

developed byt NIST (subpart A of 10 

CFR part 436). · 

The three to five-year payback for the 

non-federal sector is .responsible. It 

should be noted thatthe DOE costbenefit analysis indicates that muc.h 

shorter paybacks are possible When 

factoring costs related to lower standby 

loss levels. 

d. V.alue of Energy Savings; GAMA 

commented that DOE's analysis 

overestimated the va:lue of energy · 

savings for gas water heaters. DOE 

estimated an annual energy savings of 

$32.53 fora 100-gallon gas water heater, 

with 70 percent loss through the jacket. 

Mr. Stanonik of GAMA believed the 

annual energy savings estimate should 

be between $9.33 and $13.34, depending 

on the variables used in the analysis.' 

DOE Response: DOE has reviewed the 

calculation of savings in Table 5 of the 

Preliminary Statement and concluded 

. that they were made using a base 

assumption of 0.5 inches of insulation 

and the'addition of 2 inch~s of · · 

insulation to meet the criterion, for a 

total of 2,5 inches of insulatfon. DOE 

believes that Table 5 M the Preliminary 

Statement should have been calculated 

· on a base assumption of 1 inch of 

insulation and the addition of 2 inches 

of insulation to meet the criterion; for a 

total of three inches of insulation. This 

would result in a savings of $15;80 and a 

simple payback of4.64 years. A revised 

Table 5 follows: 

TABLE 5 (REVISED).-£NERGV CoST SAVINGS AND FIBERGLASS CoSTS DUE TO DOE INTERIM STANDARDS (WITH 70 PERCENT. 

LOSSES THROUGH JACKET AT ANSl/ASHRAE/IES STANDARD 90A-1980 CoMPUANCE LEVELS). 

Tank capacity· (gallons) · Energy savings (dollars) Fiberglass {dollars) Total • (doUars) Payback years 

100 ................•......... -............................. 15.80 .................................. -........ 29.34.-......................................... 73.35; ......................... _ ............... 4.64 

129 .... : .. , ................................................... 14.89 ....... : ................................... : 22,01 ............................................ •5s.01 ............. ; ..... .;_ ................. :. 3.69 

:~~ :::::::::::::::::::::::::::=:::::::::::::::::::::::::=:· ~~:~: :::::::::::::::::::::::::::::;:::::::::: ~ i~; ::::::::==:::::::::::::::::::::::::::::::· ~:~~ ::::::::::::::::::::::::==::::::::::::::: ~:~: 594 .......................................................... 22:14 ... - ....................... ; .............. 1s.n ............. , ............................. 46.91 ............................... ~ ............ 2.12 

•The total cost. is based on studies· that show the· !Ola! ·increased cost is approximately 2.5 limes the cost of the fiberglass· insulation. (See Blue 1979.) 

Note.-That the above table does not · 

adjust for fitting losses, (See the comment 

and response of Water Heater Fittings 

above.} · · 

Table D-5 of the DOE Technical 

Support Document provides 

performance values for a water heater 

operating under the ANSI standby loss 

test conditions for gas water heaters. 

These values were used. simply to 

determine the additional insulation that 

would be required to attain compliance 

with the DOE standards. In GAMA's 

example, the 100-gallon gas water heater 

required an additional two inches of 

insulation for compliance, bringing the 

total level to three inches. To estimate 

annual savings that would be realized 

with the additional two inches of 

insulation, performance calculations 

were made for the 100-gallon water 

heater model, except that operating 

conditions were set to typical operation 

values, not the standy loss test values, 

i.e., room temperature was set to 72.5°F 

and water temperature was set fo 140°F. 

Table E-1 of the DOE Technical Support 

Document indicates the expected 

savings that would result from the 

insulation increase. It is unnecessary to 

try lo calculate savings from values in 

Table D-5, which were obtained under 

standby loss test conditions and not 

typical operating conditions. For an · 

insulation change from one to three 

inches. Table E-1 shows that annual 

savings will be $15.80. The simple 

payback is 4.64 years. This payback 

period remains well under the 

acceptable limit for Federal sector 

projects and within the Gfu'JA 

estimated five year life of units. ~ ' , ~ 

F. Proposed Alternative Standby Loss 

Criteria 

1. General 

GAMA recommended that DOE revise 

its standards to exclude from the 

standby loss criteria storage water 

heaters with more than 120-gallon 

storage capacity. The DOE standards 

exempt storage water heaters and hot 

water storage tanks having more than 

500 gallons of storage capacity from the 

standby loss requirements if the tank · 

surface area is thermally insulated to R12.5 and if a standing pilot light is not 

used. GAMA pointed out that its 

suggestion of the 120-gallon limit was 

due to cmnmercial storage water heaters 

greater than 120-gallons being cusl.om 

. built, as stated in the Preliminary 

Statement. 

DOE Response: A point of 

darification is necessary. In its 

Preliminary Statement, DOE 

acknowledges that many storage water 

heaters over 120 gallons are custom 

made. This is not to imply that DOE has 

data showing that all are custom made. 

DOE has no such data and neither 

GAMA nor the manufacturers have 

provided such data. 

The Preliminary Statement indicates 

that many, but not all. commercial 

storage water heaters over 120 gallons 

are custom made. Therefore,. to 

categorically exempt units over 120 

gallons from the standby loss criteria 

could lead to potentially high levels of 

energy loss as a result of their use. DOE . 

feels that it is appropriate to continue to 

apply the standby loss criteria, and the 

resulting test procedures to units over 

120 gallons in size. 

2. Instantaneous Water Waters 

GAMA contended that DOE has 

redefined instantaneous water heaters 

in its standards by adding a maximum 

10-gallon parameter. The DOE standards 

define instantaneous water heaters as 

devices w.ith an input rate.greater than 

4,000 Btu/h per gallon of water stored 

and less than 10 gallons of storage 

capacity. They contend the definition 

immediately recategorizes a number of 

models that are presently considered 

instantaneous water heaters as storage 

water heaters and thus subjects those 

models to a standby loss criteria for the 

first time. Mr. Stanonik of GAMA 

argued that DOE did not analyze the 

effect of the standby loss requirements 

on these models. Without such analysis, 

the revised definition is not justified and 

the standards should be revised to the 

current industry definition of 

instantaneous water heater, which'iS "a 

water heater having an input of more 

than 4,000 Btu/h per gallon of stored 

water." 

Tom Wutka of CIGNA contended that 

DOE should use the ASHRAE/IES 

Standard 90.1-1989 water heating 

criteria. This standard uses a definition 

that defines a storage water heater as a 

water heater that has an input rating of 

less than 4,000 Btu/h per gallon of stored 

water or a storage capacity of10 gallons 
 55FR23842

·. Fedm:al Register I Vol.:· 55; ·No.113, l Tu~sday;June"12, 1990 I Rules and Regulations 23865 

or more. It defines a non-storage water 

heater as a water heater that has an input ratjng of at least 4,000 Btu/h per 

gallon of stored water and a storage 

ca pa city of less than 10 gailons. 

DOE Response: DOE has evaluated 

the conflicting comments and concludes 

that the definitions in ASHRAE/IES 

Standard 90.1-1!)89 meet DOE's intent to 

'separate the two categories of water 

heaters. It has been DOE'$ intent to 

separate instantaneous water heaters 

from storage water heaters so that 

instantaneous water heaters are limited 

to "in-line'.' water heating. The 10..gallon 

cut off was consciously established to 

eliminate any confusion over the 

definition of storage water heater and 

instantaneous water heaters, 

respectively. If DOE were to use the' 

de{inition of water heaters having an 

input of more than 4,000 Btu/h per gallon 

of stored water proposed by GAMA and 

State Industries, the new definition 

would shift many storage water heaters 

into the instantaneous category and 

exempt them from the corresponding 

standby loss criteria. This has never 

been DOE's intent and DOE has 

received no convincing justification for 

doing so. In the Preliminarv Statement, the 

wording on page 49°727 of 54 FR 49724 

defined storage water heaters as having 

an input rating of less than 4,000 Btu/h 

per gallon and a storage capacity of 

more than 10 gallons. This raises the 

potential for confusion as shown in 

Table 2. 

TABLE 2. DOE STATEMENT OF REASONS (11/30i89) 

lnput 

Storage Capacity >-------"------

<4000 Bt11/h/gal Btu/h/gal 

> 10 Gallons ..... :"·· Stornge: Water lns""~ntaneous: f!? Heater.· 

<10 Ga!iona .•.•..•... } Storage:???··········"'· 1nst2ntar.eotis: rn 

In its netvly published Standard 90.1-

1989, ASHRAE has defined the water 

heater categorfos as shovv'TI in Table 3 .. 

used the word "and" in the Preliminary 

Statement, thus causing the differences 

seen inTables2 and 3. 

DOE concludes that the ASHRAE 

proposal meets DOE's long term 

intention and avoids conflict with tbe 

water heater industry definition of 

"instantaneous water .heater~'. 

3. Electric Water H~aters. 

Four comments suggested revisions to 

the 1.9 w/ft 2 standby loss requirements 

for commercial electric storage water 

heaters. Rheem Corporation and GAMA 

maintained that if DOE agrees to 

reference the tanks surface area, instead 

of the jacket surface area, for placement 

of insulation, DOE's goal of lowering 

, standby loss becomes more feasible. 

· They stated that the DOE standby loss 

requirement of 1.9 W /ft2 is too low and 

should be modified upward, Also, they 

suggested that the requirement be 

strudured to separate out losses that 

cannot be reduced by adding insulation; 

such as those that ,occur in smaller units 

because of higher volume-to-surface 

area relationships. 

Their sugge'stion is as follo\vs: 

SL<25 W + 2.6 W /fi 2 cif tank s~rfac~ area for 

water heaters up to 120gallons .. 

Equutjon 1. 

Their comment stated that the 25 W 

constant is the same as in the original 

standby loss requirement proposed by 

DOE in 1984 [USDOE, 1984]. In light of 

the fact that DOE's 1.9 W /ft 2 of jacket 

surface area translates to about 3.2 W / 

ft 2 of tank surface area, they pointed out 

that the suggested requirement is very 

close to DOE's requirements for two of 

the most popular sizes of commercial . 

electric storage water heiJ.ters. · 

DOE also received two comments and 

detailed backgro11nd materfal from Dr. 

Golqstein of NRDG mairitain~ng .that the. 

j .9 W / ft 2 requirement was too high, Dr. 

GoldsteiI). arg1rnd that. DOE had . 

prmi!dedsufficient technical 1malysis to 

support a 1.s2 w I ft 2 standby loss level. 

Dr. Goldstein also contended that the 

DOE Technical Suppcrt Document 

demonstrates that increasing insulation 

beyond the levels required to mest the 

DOE standby loss criteria are costt~ffective, and should not be reduced. 

Dr. Goldstein maintained the 

following: that Table C-1 of the 

Technical Support ~~·'"'u'"""" 

insulation to a 

last increment of insulation from 3¥.a 

inches to 4 inches. This ranges from 7.1 

years for the 120-gallon units to 3.8 years 

for the 50cgallon units. Assuming a 12-

year life for the water heater, the 

payback period of less than 8.9 years is 

cost-effective at real discount rates of 

five percent or less. Since energy .supply 

costs are typically evaluated at discount 

rates of two percent to four percent, a 

five percent rate is conservatively high, 

pro-ving cost-effectiveness. The results 

are so striking that for two of the three 

sizes analyzed by DOE, the payback 

periods would apply cost-effectiveness 

even at a seven percent real discount 

rate. Thus, taken from an incremental 

. cost-effectiveness point-of-view, four 

inches of insulation, corresponding to a 

standby loss of about 1.52 W /ft2 , is the 

economic optimum point for the building 

owner. Dr. Goldstein concluded that a 

requirement for the maximum 

improvement in efficiency that is 

economfoally practicable can ask no 

less than the level of efficiency 

represented by the minimum life cycle 

cost point. 

Dr. Goldstein stressed that DOE must 

revise its standards to agree with the 

new calculations. 

DOEResponse: Based on the public· 

comment and other information 

received, DOE has decided to amend its 

criteria for commercial electric storage 

water heaters. 

At a February 11, 1990, meeting of the 

Service Water Heating Subcommittee of 

SSPC 90R, GAMA presented a handout 

that proposed a revised requirement for 

standby losses for electric water 

heaters. The equation presented was: 

SL<25:W + 1.6W /ft2 of external jacket area 

Equatlo1"1 2. . 

Note that this equation is for external. or 

jacket surface area, while the 

recommendation to DOE pertaiqs to 

tank surface area and uses 2.6W /ft2 • 

To calculate the standbv loss criteria 

in Watts using this equati~n, one would 

have to multiply !he area of the water 

heater jacket by 1.6 and then add 25 

Watts. To calculate the criteria in 

Watts/ft 2 of external surface are·a, one 

would divide 25 bv the tank's external 

surface area and ~dd 1.6 W/ft 2 • 

To compare both of the above 

standby loss equations with 

th.a current 4 of tank a:;ea and the 

'1.9 of 
 55FR23842

23866 Federal Register / Vol. 55; No. 113 / Tuesday, June .12, 1990 / Rules and Regulations 

Table 4 - Comparison ot Proposed GAMA Standby Losa Criteria tor Electric Water Heaters 

Volume fGJ At I tt2l Aj (!t2) Eq. 1 SL (W! Eq. 2 SL (WJ 

(baaed on tank) 

50-52 20-23 

60-85 26~32 

1:'0 38-41 

To further compare Equations 1 and 2, 

DOE looked at the criteria values that 

would apply to sample tanks of 50-, 60-

and 120-gallon storage capacities. The 

(baaed on jacket) 

35-39 61.0-87.4 

44-45 95.4-97.0 

54 111.4 

insulation thickness on these tanks were 

varied to determine when, in terms of 

standby loss in total Watts, the 

equations would be equivalent. Table 5 

77.0-84.8 

97.8-108.2 

123.8-131.6 

shows the insulation levels near which 

the two equations become equivalent for 

the sample water heaters. 

Table 5 - Comparison of Criteria tor Sample Electric Water Heaters 

TYPE HEIGHT DIAMETER GALLONS INS TANK AREA J. AREA GAMA l GA.'!A 2 

(ft) (ft) (in) (ft2 ) (ft2 ) (W@ 1.6)(\11@ 2.6) 

ELEC 

ELEC 

ELEC 

ELEC 

ELEC 

ELEC 

3.06 

3.06 

4.05 

4.05 

4.35 

4.35 

DOE agrees with the comment that a 

revision in the standby loss criteria to 

reference tank surface area versus 

jacket surface area is appropriate. 

DOE's current analysis considers losses 

that cannot_:becontrolled by the 

addition of insulation to the tank. 

Including these losses in the total loss 

figure still allows for the calculation of a 

meaningful W /ft 2 figure of merit for the 

particular water heater. However, the 

comment is incorrect in stating that the 

1.9 W /ft2 of jacket area translates to 3.2 

W /ft 2 of tank area is incorrect. Actually 

the conversion between the jacket and 

tank is shown in Table 5. 

DOE has conducted additional 

analysis to analyze the opposing 

requests and several other comments 

received, such as the effect of using a 

water heater jacket emissivity of 0.5 versus 0,9. -

DOEfinds that 3 W/ft 2 is a 

practjcable standby loss c.riteria for its 

electric storage water heatel'S of the size 

and input ranges discussed in tl}is . . . 

Response and Amwuncement and. has 

adopted it as Jts new c.ornrnercial . 

1.67 

1.67 

1.83 

1.83 

50.00 

50.00 

80.00 

80.00 

3.00 

3.50 

3.50 

4.00 

20.43 

20.43 

28.54 

28.54 

31.67 

33. 77 

44.26 

46.79 

75.67 

79.03 

95.84 

99.66 

78.13 

78.13 

99.22 

99.22 

2.17 120.00 

2.17 120.00 

4.50 

5.00 

37.05 

37.05 

60.16 121.20 121.33 

63.07 125~92 121.33 

electric storage water heater standby 

loss level. 

Table 6was created to compare the 

new criteria for electric water heaters 

with existing DOE criteria,jacke~ · 

surface area versus tank surface area, 

the ANSI/ ASHRAE/IES Standard 90A1080, tne GAMA proposal. the NRDC 

proposal,.and the test.data collected by 

NIST. The table.is confined to those 

sizes of commercial electric water 

heaters that predominate the industry, 

as stated by GAMA and the 

commenting manufacturers-50, 80, 120 

gallons. 

The DOE Interim Standards require a 

standby loss level of no more than 1.9 

W /ft 2

• In comparison, the currently 

produced 50-gallon unit tested by NIST 

had 3.06 W /ft 2 standby loss of jacket 

surface area. When modified by 

additional insulation, the NIST test unit 

performed with a 2.47 W/ft 2 standby 

loss. Neither the currently produced unit 

nor the.modified unit would meet the 

DOE standards.· · · · 

Both GAMA and ASHRAE suggested 

to DOE that referencing tank surface 

area would produce a more practical 

criteria. DOE has agreed. The tank 

surface area equivalent to the. current 

DOE criteria translates into 2.95 W /ft 2 

for a 50-gaUon model, 2.78 W /ft 2 for an 

80-gallon model, and 2.66 W /ft 2 for a 

120-gallon model. The NIST 50-gallon 

test unit showed a tank surface area 

equivalent of 4.06 W /ft 2 unmodified and 

a 3.29 W / fi 2 modified with additional 

insulation. Again neither would meet a 

tank surface area equivalent of the 

currerit DOE standby loss criteria. 

However, these units would meet the 

current ASHRAE criteria set in 1980 of 4 

WI ft 2 of tank surface area. 

The GAMA proposal discussed above, 

translates into a standby loss criteria 

level of 3.82 W /ft 2 of tank surface area 

for 50-gallon units, 3.47 W /ft 2 for 80-

gallon units, and 3.27 W /ft 2 for 120-

gallon units. These all would be lower 

than the current ASHRAE levels set in 

1980 but orily W to 18 percent lower: The 

DOE analysisindicatesthat at least a 25 

percent reduction is practical and costeffective. - · 
 55FR23842

Federal Register l Vol. 55, No. 113 I Tuesday, Ju'ne 12, 1990 I Rules and Regulations 23867 

The NRDC proposal suggests that a 

1.52 W /ft2 of jacket surface area is 

practicaLaccording to DOE's analysis in 

the Preliminary Statement. Dr. Goldstein 

is correct in his assessment, however, 

DOE believes its estimates were 

optimistic for a standby loss criteria 

r~Jer·encing jacket surface area. 

Tnerefore, DOE is not inclined to reduce 

the standby loss criteria any further. 

As such DOE has set its standby loss 

criteria level for electric storage water 

heaters at 3.0 W /ft 2 of tank surface area 

for all size units. This represent?! a 25 

percent reduction in current standards. 

It means that units built with 2.75 to 3 

inches of foam insulation surrmmding 

the tank and R-8 fiberglass on the 

conti:ols, or 6.5 inches of fiberglass 

surrounding tank and controls, will meet 

the criteria. It will also mean that the 

larger units will have an easier time 

meeting the criteria because of their 

larger tank volume to surface ratio, as 

indicated by item two in table 6. 

Table 6 - Comparison o! Standby Loss Criteria 

Nominal Tank Capacity 

Alternative cr-1ter1a 50 Gal 80 Gal 120 Gal 

DOE Statement cf Reasons 

[W/ft2 of jacket area] 

NIST tents [modified/with blanket] 

1.9 1.9 1.9 

p.06/2.47j 

DOE estimated tank equivalent of the 

jacket area [W/ft2 of tank area] 

NIST tests [modified/with blanket) 

2.95 2 .• 78 2.66 

[4.06/3.29] 

DOE estimated percent loss equivalent 

[percent of stored energy per hour] 

NIST tests [modified/with blanket] 

0.530 0.520 O.t30 

f0.99/0.77] 

ANSI/ASBR.1\.E/IES Standard 90A-1980 

and 90-1975 [W/ft2 of_.tank llrea] 

4.0 

GAMA p~opcsal [converted to 

W/!t cf tank surface area) 

3.82 

NRDC pr9posal 1.52 1.52 

(W/ft" of tanll area] 

DOE acknowledges t1ie support for its 

e"isting criteria and the 

recommendation to extend it futther. 

However, DOE observes that the 

original analysis did not include the 

losses from fittings and controls, thus 

overstating the benefits of adding 

insulation. It is aiso noted that no 

manufacturer currently produces a 

model which has been tested and found 

to meet the current standby loss criteria. 

The argument of a 12-year life for 

commercial water heaters may not be 

valid in light of contentions about the 

life of water heaters made by the 

manufacturers. Until more definitive 

data become available, DOE believes it 

is appropriate to use its more 

conservative analysis. 

4. Gas Water Heaters 

Rheem Corporation and GM4A 

suggested revisions to the categorization 

of gas storage water heaters. They 

suggested that DOE separate gas storage 

water heaters into two categories-

<155,000 Btu/h and>155,000 Btu-so 

that manufacturers of water heater 

modeis not currently equipped with flue 

dampers and IIDs, generally those 

155,000 Btu/hand lower, do not have to 

add them to meet the DOE standards. 

The lower requirement for the higher 

input models recognizes that these 

models already are equipped with flm~ 

dampers and IIDs. The suggested 

requirements are as foilows: 

Inpuh;;155,000 Btu/h is SL.;:1.3+120iV; and 

Equation .'J. 

Input> 155,000 Btu/his SL;,;1.3+ 100/V. 

Equotjon 4. 

GAMA further proposed an exception 

to the basic formula for maximum 

allowable standby loss. Mr. Stanonik 

contended that flue dampers and IIDs 

are not cost effective on commercial gas 

storage water heaters wifa inputs up to 

approximately 200,0C"() Btu/h and that 12 

percent or less of water heaters sold 

have storage vessels greater than 120 

gallons. Mr. Stanonik proposed the 

4.0 

3.27 

1.52 

following exceptions: for gas water 

heaters having an input rating not .over 

200,000 Btu/h and not requiring an 

external power. source, the standby loss 

in percent per hour shall not exceed 1.3 

+ 368/V; for all types of storage water 

heaters-gas, electric, and oil-with 

capacities greater than 120 gallons, they 

shall be insulated to limit heat loss to 

605 Btu/h/ft 2 of tank surface area. · 

DOE Response: DOE appreciates the 

suggestions for alternate criteria. DOE 

notes, however, that the commenter did 

not include documentation to support 

the proposed criteria. Test data supplied 

by the CEC shows several units that 

currently meet DOE's standby loss 

criteria, One of the manufacturers of 

those units supports the standby loss 

criteria at its current level. While there 

was a following letter qualifying these 

comments, DOE found it unpersuasive. 

Additional units tested by CEC indicate 

compliance with the ASHRAE 90A-1980 

standard without flue dampers and IIDs. 

Estimates of the benefits of flue damper~ 
 55FR23842

23868 Federal Register / Vol. 55, No. 113 I Tuesday, June 12, 1990 f Rules and Regulations 

and IIDs applied to these units indicate 

that all would comply with the current 

DOE criteria. DOE feels that it has 

promulgateCI criteria which is 

reasonable, cost-effective, and can be 

met with current technology and 

manufacturing practices. 

V. Conclusions a.."ld Appropriate 

Standby Loss Criteria 

The following is a discussion of the 

conclusions reached by DOE in 

connection with this announcement of 

final storage water heater standby loss 

criteria and the reasons for its decisions. 

DOE's decisions are based on its 

consideration of the comments received, 

additional computer modeling, and the 

tests conducted by NIST on an electric 

water heater and a gas water heater. 

As stated in Section III, the water 

heaters included in this Response and 

Announcement are limited to the 

following: (i) Electric storage water 

heaters of greater than 120-gallon 

capacity or of greater than 12 kW input 

rating; (ii) gas storage water heaters of 

greater than 100-gallon capacity or 

greater than 75,000 Btu per hour input 

rate; and (iii) oil-fired storage water 

heaters of greater than 50-gallon 

capacity and greater than 105,000 Btu 

per hour input rate. Storage water 

heaters having more than 500 gallons of 

storage capacity are excluded if the tank 

surface area is thermally insulated to 

R-12.5 and a standing pilot light is not 

used. At issue are the standby loss 

criteria set by DOE for these water 

heaters, which some have contended are 

too high or too low. A second issue is 

the difference between storage and 

instantaneous water heaters. The 

specific q11estion is whether to include 

high power water heaters in the 

category of instantaneous water heaters 

and, therefore, eliminate standby loss 

requirements for these units. The 

purpose of this Section is to discuss the 

appropriate standby loss criteria and the 

bases for DOE's determination. 

In addition, the DOE Interim 

Standards reference recognized test 

procedures to determine water heater 

standby loss. The referenced test 

procedures were developed by ANSI 

and DOE. The reliability of the test 

procedures is not in question at this 

time, although recommendations have 

been made to DOE to consider 

recognizing updated test procedures for 

commercial electric storage water 

heaters. 

With due consideration of the 

comments that have been received and 

the results of further tests and analyses 

that DOE has caused to be conducted, 

and in accordance with the remand 

procedure provided for in the Court's 

October 6, 1989, Memorandum and 

Order, DOE is announcing and adopting 

the water heater standby loss criteria 

set forth in Table 9.3-1 below (part 435 

of chapter II of title 10 of the Code of 

Federal Regulations subpart A, 

§ 435.109, Table 9.3-1, Standard Rating 

Conditions and Minimum Performance 

of Water Heating Equipment). 

PART 435-ENERGY CONSERVATION 

VOLUNTARY PERFORMANCE 

STANDARDS FOR NEW BUILDINGS; 

MANDATORY FOR FEDERAL 

BUILDINGS 

1. The authority for part 435 continues 

to read as follows: 

Authority: Energy Conservation Standards 

for New Buildings Act of 1976, as amended, 

(42 U.S.C. 6831-6870), enacted as Title Ill of 

the Energy Conservation and Production Act; 

(42 U.S.C. 8201, et seq.): (42 U.S.C. 8255); 

section 545, Natiohal Energy Conservation 

Policy Act; Department of Energy 

Organization Act, (42 U.S.C. 7101 et seq.) 

§ 435.109 [Amended] 

2. In § 435.109, Table 9.3-1 is 1·e~;ised 

to read as follows: 

BILLING CODE 6450-01-!'A 
 55FR23842

Water 

Heat~rs 

Federal Register I Vol. $5, No, 113 I Tuesday, June 12, 1990 I Rules and Regulations' 

Table 9.3-1 (Revised June 12, 1990) 

Standard Rating Conditions & Mini~um Performance of Water Heating Equipment 

I I j Electric! 

Storage Input 

capacity Rating 

(Gal) 

!,120 5._12 kW 

Applicable Te~t Procedure Minimum Performance 

DOE Fating Eft. 

DOE T~st Procedures, 1985 

Code of Federal Re~ulaI I tiona Title 10, Part 430 ~o.9s-o.oon2v 

1

1,i 1----,0-+-)1'-1 ------------t------.....+---+------1 >120 >12kW DOE Test Procedures! 1990 - - SL 

Code of Federal Regulat tions Title 10, Part 430 - - <3.0 W/ft2 

i------r--~~~~i~~~~-t-~~~~-~-~~~~~-t-~~~~-~~-1-~~-t-~~~--1 

!100 ;:::75,000 

:atu/h 

Gas I DOE Tast Proceclures, 1985 

Code of Federal Regulations Title 10, Part 430 

EF 

;:,0.62-0.0019\7 l 

I r·~->-10-'0-l~o-r_)_>_7_5_,_0_0_G-+-Al-~-G-l_Z_2_l ___ l_0-.-3--1-9-S-~~--~--+l~-~~-~~+--E-t__,.l.~~S-L~""1 

l Btu/!! Ga"' Watsr Beate:r·s I . ~ l l Ii ~~,. 'O·" ' •I"'""''-' '" . "" •. ,,,, I - "' <;;~ I cu I ~ -'-' ,. DOl!: Test Proc'1!<irnres, 1%5 1--~:i'' -

I

I a;:i.;/ll Code of FsC.eral 11.sgula- I . . I 

~so ~1os,ooo 

rrtu/h 

>105,000 

l!tu/h 

ticns Title 10, Part 430 I ~{L59-0.()0J.9V - -

SL 

<l..J+ 

23869 
 55FR23842

23870 Federal Register/ Vol. 55, No. 113 /Tuesday, June 12, 1990 I Rules and Regulations 

Table 9.3-1 (Revised June 12, 1990) 

Standard Rating Condition.a & Minimum Performance of Water !!111ating Equipment (Cont.) 

Type 

Applicable Test Procadure 

Input 

Class F!l'el Capacity Rating 

Unfired 1 All All 

Storage Volume Inputs 

Non-Storage2 Gas - All ANSI Z21.10.3-19B4 

W<iter Heaters Inputs 

Distill All 

OU - Inputs 

Pool Gas/ All ANSI Z21.56-1986 

Heater a OU - Inputs 

Rotes tor Table 9.3-1: 

Terms Defined: 

1. EF" Energy factor, overall heater efficiency by DOI TestProceduro 

Et " Thermal efficiency with 70°F, •T 

Minimum Performance 

- HL 

- <6.S 

Btu/il"ft2 

"t -

BO' -

Ee -

83\ -

Et. - 78\0 -

Ee • Combustion cfficienc2' 100 percent - flue lose when smoke • 0 {trace is permitted) 

SL• Standby loss in W/ft based on ao•F, AT, or in percent per hour based on nominal so•v, •T 

HL • Heat loaa of tank.surface area 

V • Storage volume in gallons 

2. A non-storage water heater is a device with an input rate-greater than 4000 Btu/h/gallon ot water 

®tored or less than 10 gallons of storage capacity. A atorage water heater is a water heater that has 

an input rating of less than 4000 Btu/h per gallon of atorred water or a storage capacity of less than 10 gallona • 
 55FR23842

Federal Register I Vol. 55, No. 113 I Tuesday, June 12, 1990 l Rules and Regulations 23871 

A. Instantaneous Water Heaters 

DOE has determined that the 

definition of instantaneous water 

heaters used'in the January 30, t989, 

DOE Interim Standards and the 

definition used in the November 30, 

1989, Preliminary Statement, should be 

modified to match the definition utilized 

by ASHRAE/IES Standard 90.1-1989. 

GAMA contended that DOE had 

changed an accepted definition of 

instantaneous water heaters by adding a 

maximum ten-gallon parameter to 

devices with an input rate greater than 

4000 Btu/h per gallon of water stored 

and subjecting the remaining models 

( > 10-gallons and > 4,000 Btu/h per 

gallon) to a standby loss criteria for the 

first time. As previously indicated, if 

DOE were to use the industry definition 

of water heaters having an input of more 

than 4,000 Btu/h per gallon of stored 

water, the new definition would add 

many storage water heaters into the 

instantaneous category and exempt 

them from the corresponding standby 

loss criteria. It has been DOE's intent to 

separate instantaneous water heaters 

from storage water heaters so that 

instantaneous water heaters are limited 

to "in-line" water heating. The 10-gallon 

cut-off was established to: eliminate any 

confusion over the definition DOE has 

chosen to use. The DOE standards now 

cover instantaneous water heaters with 

separate storage tanks. In the future, 

DOE will use the same definition found. 

in ASHRAE/IES Standard 90.1-1989. 

This definition is included in Table 9.3-1 

(revised June 12, 1990). 

B. Electric T11ater Heaters 

1. Test Procedures 

In its January 30, 1989 Interim 

Standards, DOE listed ANSI Standard 

C72.1-1972, American National 

Standard for Household Automatic 

Electric Storage-Type Water Heaters, as 

test procedures for establishing standby 

loss performance. DOE has 

subsequently learned that the ANSI test 

procedure is no longer supported by 

A.."JSI. Accordingly, in the future. DOE 

will require that all tests be conducted 

in accordance with DOE's test 

procedure for electric water heaters. {10 

CFR part 430, January 1, 1990.) This test 

procedure requires a test setup similar 

to what will be required of the piping 

around the unit in actual conditions, 

including insulated heat trap and inlet 

and outlet piping. The DOE test 

procedure is well understood by 

manufacturers and testing laboratories 

and is widely recognized in the building 

industry. 

2. Tank Surface Area vs. Jacket Surface 

Area 

In addition to the suggestions to revise 

the 1.9 W /ft 2 standby loss requirement 

for commercial electric storage water 

heaters, several comments suggested 

that DOE express its criteria in terms of 

tank surface area, instead of the jacket 

surface area. ASHRAE indicated that it , 

had clarified its criteria as pertaining to 

tank surface area. DOE initially used the 

jacket surface area because that is what 

was required by the now unsupported 

ANSI test procedure. Industry 

commenters suggested that DOE's 

requirement of 1.9 W / ft 2 of jacket 

surface area translates to about 3.2 

WI ft 2 of tank surface area or what was termed very close to DOE's 

requirements for two of the most 

popular sizes of commercial electric 

storage water heaters. 

DOE agrees with the comments and in 

its announced criteria expressed its 

requirements in terms of tank surface 

area instead of jacket surface area. DOE 

believes that criteria expressed in terms 

of tank surface area is more often used 

and that it will help to avoid confusion 

of specification "rriters between the 

DOE criteria and that adopted by 

ASHRAE. Table 6 shows specific 

examples of the numerical-differences 

between tank and jacket surface area 

for water heaters that would meetthe 

DOE standby loss criteria,:. 

3. Watts/ft 2 vs. Percent of Stored 

Energy 

The industry uses criterion for gas 

storage water heater standby loss 

expressed in percent stored energy loss 

per hour. The appropriateness of using a 

standby loss expressed in terms of 

stored energy loss is attributable to the 

fact that the precise temperature of the 

test room is no longer critical to the 

results. In addition, as the calculation is 

done in terms of tank volume, it is easy 

to measure that volume. One fills the 

tank, measuring the amount supplied, or, 

if capable of being fully emptied, 

empties it, and measures the volume of 

the contents emptied. This would also 

have the advantage of expressing the 

standby loss for all "commercial size" 

water heaters in the same terms. Finallv, 

both manufacturers and testing • 

laboratories are familiar with standbv 

loss being expressed in these terms a'Ild 

those who test units are already set up 

to do these measurements. 

It has been recommended that DOE 

express the standby loss for electric 

water heaters in terms of percent of 

stored energy loss per hour. DOE has 

determined not to do so at this time, as 

additional information is needed on the 

implications of such a decision. During 

the remainder of the demonstration 

period for the DOE Interim Standards, 

DOE will continue to evaluate the 

desirability and effects of changing the· 

electric storage water heater criterion 

from criterion expressed in lank surface 

area to criterion expressed in percent 

per hour. How.ever, for purposes of this 

publication, DOE's electric storage 

water heater criterion is expressed in 

terms of tank surface area and any 

subsequent change of this standard 

would need to be justified on the basis 

of the statutory guidelines, including 

energy efficiency, economic cost and 

benefit, and impact on affected groups. 

In the event DOE is considering a 

change of this nature in connection with 

the forthcoming issuance of final 

standards, it will so indicate in the 

Notice of Proposed Rulemaking at that 

tLrne and request comment on the 

feasibility or appropriateness of such a change. 

4. Establishment of DOE Criteria 

DOE received comment from GAMA 

and three water heater manufacturers 

indicating that the DOE standby loss 

requirement of 1.9 W /ft 2 is too low and 

should be modified upward. They 

suggested that the requirement be ~ 

restructured to separate out losses that 

cannot be reduced by adding insulation, 

such as those that occur in smaller unitsbecause of higher volume-to-surface 

area relationships. 

Their suggestion is contained in 

Equation 1, repeated below: 

SL = <25 W + 2.6 W /ft 2 of the tank surface 

area for water heaters up to 120 gallons 

Equation 1. 

Dr. Goldstein of NRDC maintained 

that the L9 W /ft 2 requirement is too 

high. He argued that DOE had provided 

sufficient technical analysis to support a 

1.52 W /ft 2 standby loss level. 

DOE has conducted additional 

analysis of opposing views and several 

other comments received,_such as the 

effect of using a water heater jacket 

emissivity of 0.5 versus 0.9. DOE finds 

that 3 W /ft 2 is a practicable and costeffective standby loss criterion for 

electric storage water heaters of the size 

and input ranges discussed in this 

Response and Announcement and 

adopts it as DOE's new commercial 

electric storage water heater standby 

loss criterion. 

DOE bases this decision on tests of a 

storage water heater, additional 

information developed on other losses, 

such as fittings and controls, excellent 

correlation of test and model results, 

and a new cost benefit analysis. Figure 6 
 55FR23842

23872 Federal Register I Vol. 55, No. 113 / Tuesday, June 12, 1990 I Rules and Regulations 

presents the analysis of a 50, 80, 120 and 

170 gallon capacity electric storage 

water heaters, respectively, for a range 

of insulation thicknesses up to 7 inches. 

Tables 8, 9, 10, and 11 provide the data 

on which Figure 6 was based. 

131LLING CODE 6450--01-M 
 55FR23842

Federal Register I Vol. 55, No. 113 I Tuesday, June 12, 1990 I Rules and Regulations 23873 

ELECTRIC WATER HEATER STANDBY LOSSES 

Emissivity=.9, 40% Other Loss Reduct.ion 

,......., 

~ 5-+-,-:..-~----~--~-----~---~·------; 

0 

1-

J_ 4.5 .... 

g 4-1--~->.,,.------~--------------------l 

'., 

~ 3.5 +---i'i~c-=----------

Ill 

-l fj 3 +-------- £2,5+--------~::....,-~~.------=--=="llB-----~~---==----~~ 

"'tl 

c 2 2t---~~~~~~-""'-~:§:::~F=:;;::=::'.:==-+---=r==F~ VJ 

1.5 I 

LO 1.5 2.0 2.5 3.0 3.5 4,0 4.5 5.0 5.5 6.0 6.5 7.0 

Insulation Thickness (in.) 

Galion -+- 8 5 

Figure 6 - Analysis of Electric Water Heaters - 50, 80, 120 & 

170 gallon capacity 
 55FR23842

2387~ Federal Register / Vol. 55, No. 113 / Tuesday, June 12, 1990 / Rules and Regulations 

Table 8 

ELfCTRIC STANDBY LOSS CALCULATIONS BASED ON TANK 

LOSSES CORRECTED TO 80 DEGREES DELTA T 

ELECTRIC WATER HEATER 50 GALLON 21.67 SQ FT-TANK 7':>.~ FOAM, 25% GLASS 0.9 EMISSlVIT 40% REDUCTiON OF OTHER LOSSES 

J NSUL Q TOP Q SIDE Q BOT Q JACKET Q OTHR Q TO fAL Q TOTAL SL 

(Btu/h) (Btu/h) (Btu/h) (Btu/h) (Btu/h) (Btu/h) (Watts) (w/sq ft) 

0.0 286.33 2815.33 2i7.09 3318.75 60.51 3379.26 990 .11 47. 72 

0.5 39.67 455. 34 38.13 533 .14 60.51 593.65 173.94 8.38 

1. 0 23.90 270.10 23.40 317.40 60. 51 377.91 110. 73 5.34 

1. 5 18 .15 199 .19 17 .89 235.23 60.51 295.74 86.65 4.18 

2.0 15.21 163.22 15.05 193.48 60.51 253.99 74.42 3.59 

2.5 13.46 141.15 13.35 167.96 60.51 228.47 66.94 3.23 

3.0 12.32 126.32 12.24 150. 88 60.5i 211.39 61.94 2.99 

"· ? " ~ 11. 54 115.74 11. 47 138.75 60.51 199.26 58.33 2.81 

4.0 10.98 107.87 10.92 129.77 60.51 190.28 55.75 2.59 

4.5 10.57 101.84 10.53 122.94 60.51 183.45 53.75 2.59 

5.0 10.27 97.09 10.23 117.59 60.51 178 .10 52 .18 2.51 

5.5 10.05 93.30 10.01 113.36 60.51 173.87 50.94 2.46 

6.0 9.89 90.23 9.86 109.98 60.51 170.49 49.95 2.41 

6.5 9.77 87 .82 9.74 107.33 60.51 167.84 49.18 2.37 

7.0 9.69 85.64 9.66 104.99 60.51 165.50 48.49 2.34 

STANDBY LOSS ADJUSTED TO 80 DEG DELTA T 

82 CE698 I6.CI.N 
 55FR23842

Federal Register/ Vo[_ 55, No. 113 I Tuesday, June 12, 1990 I Rules and Regulations 23875 

Tab1e'9 

ELECTRIC WATER HEATER 85 GALLON 29.91 SQ FT-TANK 

75% FOAM. 25% GLASS 0.9 EMISS!VIT 40% REDUCTION OF urnrn LOSSES 

INSUL Q TOP Q SIDE Q BOT Q JACKET Q OTHR Q TOTAL Q TOTAL SL 

(Btu/h) (Btu/h) (Btu/h) (Btu/h) (Btu/h) (Btu/h) (Watts) (Iii/sq ft) 

=~====================================~===;=================-============= 

0.0 449.93 3761.66 344.51 4556.10 60.51 4616.61 1352.65 47.23 

0.5 62.45 601. 35 60.07 723.87 60.51 784.38 229.82 8.02 

1.0 36.90 352.66 36.14 425.70 60.51 486.21 142.46 4.97 

1. 5 27.51 257.30 27 .13 311. 94 60.51 372.45 109.13 3.81 

2.0 22.67 208.83 22.43 253.93 60.51 314.44 92 .13 3.22 

2.5 19.74 178.99 19.58 218.31 60.51 278.82 81.69 2.-85 

3.0 . 17. 80. 158.87 17.68 194 35 60.51 254.86 74.67 2.61 

3.5 16.44 144.46 16.35 177.25 60.51 237.76 69.65 2.43 

4.0 15.45 133.67 15.37 164.49 60.51 225.·00 65.92 2.30 

4.5 14.70 125.35 14.64 154.69 60.51 215. 20 63.05 2.20 

5.0 14 .13 118. 77 14.07 146.97 60.51 207.48 60.79 2 .12 

5.5 13.68 113. 46 13.63 140.77 60.51 201.28 58.97 2.06 

6. (} 13.33 109 .12 13.29 135.74 60.51 196.25 57.50 2.01 

6.5 13.05 105.53 13.01 131.59 60.51 192.10 56.28 1.97 

7.0 12.83 102. 53 12.80 128 .16 60.51 188.{)7 55.28 1.93 

Table 10 

ELECTRIC WATER HEATER 120 GALLON 39.50 SQ FT-TANK 

75% FOAM, 25% GLASS 0.9 EMISSIVIT 40% REDUCTION OF OTHER LOSSES 

rNSUL Q TOP Q SIDE Q BOT Q JACKET Q OTHR Q TOTAL Q TOTAL SL 

( Btu/h l ( Btu/h) (Btu/h) (Btu/h) (Btu/h) {Btu/h) (Watts.) {II/sq ft) 

===========~======================;;.;:===================:================= 

0.0 607.16 4957.48 447.94 6012.58 60.51 6073.09 1779. 40 47.05 

0.5 80.98 788.21 77 .93 947 .12 60.51 1007.63 295.23 7.81 

1. 0 47.41 458. 86 46.45 552.72 60.51 613.23 179.67 4.75 

1. 5 35.03. 334.53 34.55 404' 11 60.51 464.62 136.13 3.60 

2.0 28.61 269.23 28.32 326.16 60.51 386.67 113. 29 3.00 

2.5 24. 72 228.23 24.52 277.47 60.51 337.98 93.03 2.62 

3.0 22 .13 201. 41 21.98 245.52 60.51 306. 03 89.67 2.37 

3.5 20.30 182 .11 20.18 222.59 60.51 283 .10 82.95 2.19 

4.0 18.95 167.52 18.85 205.42 60.51 265. 93 77 .92 2.06 

4.5 17.92 !56.39 17 .84 192 .15 60.51 252.56 74.03 1.96 

5.0 17 .12 147.47 17.05 181. 64 60.51 242 .15 70.95 1.88 

5.5 16.48 140.24 16.43 173 .15 60.51 233.66 68.46 1.81 

6.0 15.98 134.29 15. 93 166.20 60.51 226.71 66.43 l. 76 

6.5 15.57 129.32 15.52 160.41 60.51 220.92 64.73 1. 71 

7.0 15.24 125 .14 15.20 155.58 60.51 216.09 63.31 1. 67 

STANDBY LOSS ADJUSTED TO 80 DEG DELTA T 

83 CE698 I6.CLlf 
 55FR23842

; 23876 ; Federal Register;/ Vol. 55_,No. 113 l Tuesday, June·12, 1990/1 Rules and Regula:tio)'.1$ , · 

Table 11 

ELECTRIC WATER HEATER 170 GALLON 51. 84 SQ FT-TANK 

75% FOAM,. 25% GLASS 0.$ EM!SSIVIT 40% REDUCTION OF OTHER LOSSES 

IN$UL Q TOP Q SIDE Q BOT .Q JACKET Q OTHR Q TOT~L Q TOTAL : SL 

(Btu/h) .(!1-tu/h). (Btu/h) (Btu/h) (Btu/h} (Btu/h) (Watts) (W/sq ft) 

::======================================================================= 

0.0 537.836914:44 398.60 7850.87 60.51 7911. 38 2318.01 46.70 

0.5 72.13 1102.86 69.41 1244.40 60.51 1304.91 382.34 7.70 

1. 0 42.40 640.35 41. 53 724.28 60.51 784.79 229.94 4.63 

1. 5 31.45 465.43 31.01 527.89 60.51 588.40 172.40 3.47 

2.0 ~25. 78 373.42 25.52 424.72 60.51 485.23 142 .17 2.86 2.5 22.36 316.74 22.17 361.27 60.51 421.78 123.58 2.49 3.0 20.08 278.40 19.94 318.42 60. 51 378.93 111. 03 2.24 3.5 18.47 250 .. 81 l&.36 287.64 60.51 348.15 102.01 2.06 4.0 17 .29 230.05 17.20 264.54 60.51 325.05 95.24 1.92 4.5 16.39 213.91 16.32 246.62 60.51 307 .13 89.99 1.81 5.0 15.70 201. 03 15.64 232.37 60.51 292.88 85.81 1. 73 5.'S 15.16 190.55 15.10 2,20 .81 60.51 281.32 82.43 1.66 6.0 14.73 181. 89 14.68 211. 30 60.51 271.81 79.64 1.60 6.5 14.38 174.62 14.'34 203.34 60.51 263.85 77 .31 1. 56 7.0 14.10 168.46 14.07 196.·63 60.51 257 .14 75.34 1.52 

OilllNG CODE 6450-01-C 
 55FR23842

Federal Register I Vol. 55, No. 113 / Tuesday, June 12, 1990 l Rules m:i.d Regulations . 23877· 

C. Gas Water Heaters 

As noted above, DOE received two 

comments suggesting revisions to the 

categorization of gas storage water 

lleaters. It was suggested that the 

categories be changed to <:;155,000 

Btu/h and > 155,000 Btu/h so that 

manufacturers of water heater models 

not currently equipped with flue 

dampers and IIDs, generally those 

> 155,000 Blu/h, would not have to add 

them to m~et the DOE standards. The 

January 30, 1989, DOE standards require 

fuat gas storage water heaters with an 

input rating of less than 75,000 Btu/h 

must meet the standby loss criterion of 

<1.3+38/V. The two comments 

suggested that units with an input rating 

of 155,000 Btu/h or greater are already 

equipped with flue dampers and HDs, 

DOE has not received sufficient 

information to warrant adopting the 

suggestion. Rather it believes that units 

of over 75,00Cl Btu/h are high input 

models that should be equipped with 

flue dampers and !IDs to limit energy 

waste. DOE further believes that the use 

of these high input-low storage units is 

contrary to good building design in 

many cases and most certain!v is 

counterproductive to good en~rgy 

conservati.on practice. Units with high 

demand and low storage are only 

properly used when health codes or 

other practical reasons require ondemand hot water. Even then a booster 

heater should be used. Too often the 

·units are used so as not to cause 

complaints about not enough hot water. 

In many cases, this type of cautionary 

procedure causes over-design and 

wastes energy. 

DOE also does not find any 

persuasive argument that the addition of 

flue dampers and IIDs will add 

significant production costs. The 

industry acknowledges that it is already 

building units that have such features. 

The two comments also suggested the 

following requirements: 

Input <155,000 Btu/h requires 11 SL.;:1.3+120/ 

v 

Input > 155,000 Btu/h requires a SL<:;l.3+100/V 

The January 30, 1989, DOE Interim 

Standards reouire that units of less than 

or equal to 10.0 gallons of nominal 

storage capacity and/or possess an tank top and sides; In Table 13, the 

input rating of less than or equal to figerglass was replaced by k = 0.1667 

75,000 Btu/h must meet an overall. Btu•in/h•f(2 •'°Ffoam at R-12 for 2 · 

-energy factor. Units of greater than 100 inches; Nd insulation was factored for 

gallons of nominal storage capacity the bot!om. This is consistent with the 

and/or greater than 75,000 Btu/h inrmt previous analysis performed for the 

rating must meet a standby loss · Statement of Reasons. The "Q ADD" 

criterion of <1.3+38/V. factor was adjusted until the standby 

D. Gas Water Heater Analysis loss matched that reported by NIST on the test unit-3.14 percent per hour. "Q 

As stated above, DOE is not changing ADD" is the amount of losses that must 

Hs criterion for gas storage water be added to the jacket losses calculated 

heaters. DOE bases its conclusions on by the DOE model to match total losses 

the analysis performed for the with NIST measured losses. As before, 

Preliminary Statement and additional the DOE criteria is compared with the 

analysis that was performed subsequent ' ANSI/ ASHRAE/IES Standard 90Ato the receipt of public comment. This - 11.980 •. "Q ADD" was considered to be . 

includes the testing of a gas water independent of insulation thickness, 

heater by NIST, as described below, and therefore, the DOE determined the 

the addition of analysis on a 78-gaUon percent of total losses that "Q ADD" 

model unit Several industry comments would be at compliance with ANSI/ 

suggested that DOE was not studying ASHRAEiIES Standard 90A-1980 with 

the more prevalent models when it used the standing pilot light factored out, as 

analysis on 100-, 221-, 411-, and 594- follows:. 

gallon units on which to base its conclusions. !JOA allowed loss rate =(2.3+67 /V percent per hour)/ 

Tables 12 and 13 are comparisons 100 x energy content of stored water 

made of the gas storage water heater (based on 90 °F AT) 

that ~'1ST tested with the addition of =0.03159X8.25 Btu/gallon• "FX90 °Fx78 

fiberglass and foam insulation. The gallons 

analysis used the NIST test unit that has =il830 Btu/h 

been labeled MOD1. The MOD1 unit Q ADD w/o pilot was a basic off-the-shelf unit that had =854/efficiency-pilot energy+makeup for lost energy from pilot to water 

been modified to eliminate some =1186-881+269 

unnecessary thermal bridges. For further =574 Btu/h 

information, see the NIST letter report, Q ADD% .of allowed loss 

which is included in the public record, =574/1830XlOO 

Surface emissivity was determined to be =3!.4 percent 

0.87. The unit had a flue damper. The The January 30, 1989, DOE Interim 

test unit came with a standing pilot light. Standards allow a standby loss of less 

Input for the pilot light was calculated al than 1.3+38/V or 1.79 percent for this 

881 Btu/h. For the purposes of the 78-gallon unit. 

analysis the pilot light was removed. In Standby loss is calculated as: 

doing so, 269 Btu/h were calculated as "Q TOTAL"/Efficiency/ 

having delivered energy to the stored (8.25X78X(156.764-72.566J)X100 where: 

water and thus cannot be counted in the 156.764 is the average tank water tempera lure 

energy lost. This was determined by the f'FJ during the NIST test; and 72.566 is lhe 

following calculation: average ambient temperature (°F) during the 

(

o.22){BSl Btu/hl,/0.7Z=269 Btu/h NIST test.Standby loss without the pilot light was calculated as: ("Q TOTAL"/ · 

where 0.72 is the recovery efficiency of Efficiency_:_Pifot Loss+Makeup Energy)/ 

the unit and 0.22 is the reported {8.25X78X(1~6.764-72.566))X100. 

efficiency with which the pilot delivers \'\lith a flue damper and an HD, the 

energy to the stored water. [Hoskins, unit compJies with the addition of one 

19i7] inch of fiberglass to the base two inches 

In Table 12., two inches of fiberglass or w:Hh the use of approximately two · 

insulation (R-12, or k=0.25 Btu·in/h•ft2• inches of foam insulation. . . 

°F were used, in like amounts, on the IBlWNG cooe 645iHl1-M 
55FR23842 

23878 Federal Register/ Vol. 55, No. 113 /Tuesday, June 12, 1990 /Rules and Regulatio.1s 

Table 12 

GAS WATER HEATER 

(FIBERGLASS INSULATION) 

HEIGHT DIAMETER EMIS GALLONS INS TPP INS SIDE . INS BO'l' 'l:ANK AREA J. AREA W. TEMP A. TEMP Q LOSS Q l\DD Q TOTAL SL SL W/0 PI 

( !t) (ft) (in) (in) (in) fsqft) (sq!t) · (F) (F) (Btu/n) (Btu/h) (Btu/h) (\/RR) (\/BR) 

--------~------·--·--------------------------.. -~----·------------·------------------------------------------------~----------------------------- 4.50 2.00 0.87 78.00 o.oo 'o.oo 0.00 34.56 34.56 160.000 75.000 5463.71 854.0q 6317.7l 16.042 14.923 

4.50 2.00 0.87 78.00 0.50 0.50 o.oo 34.56 36.54 160.000 75.000 767.10 854.00 1621.10 4.116 2.997 

4.50 2.00 0.87 '78.00 1.00 1.00 '0.00 34.56 38.57 160.000 75.000 441.40 as4.oo 1295.40 3.289 2.110 

4.50 '2.00 0.87 78.00 1.50 1.50 0.00 34.56 40.64 160.000 75.000 319.88 854.00 1173.88 2.981 l.862 

4.50 2.00 0.87 78 .• 00 2.00 2.00 o.oo 34.56 42.76 160.000 75.000 255.36 854.00 1109.36 2.817 1.698 

4.50 2.00 0.87 78.00 2.50 2.50 o.oo 34.56 44.92 160.000 75.000 216.70 854.00 1070. 70 2. 719 1..600 

4.50 2.00 0.87 78.00 3.00 3.00 o.oo 34.56 47.12 160.000 75 .• 000 190.56 854.00 1044.56 2.652 1.533 

4.50 2.00 0.87 78.00 3.50 J.50 0.00 34.56 49.37 160.000 75.dOO 171.77 854.00 1025.77 2.605 1.486 

4.50 2.00 0.87 78.00 4,00 4.00 o.oo 34.56 51.66 160.000 75.000 157.65 854.00 1011.65 2.569 1.450 

4.50 2.00. 0.87 78.00 4.50 4.50 o.oo 34.56 54.00 160.000 75.000 146.68 854.00 1000.68 2.541 1.422 

4.50 2.00 0.87 78.00 s.oo 5.00 o.oo 34.56 56.37 160.000 75.000 137.94 854.00 991.94 2.519 1.400 

4.50 2.00 0.87 78.00 5.50 S.50 0.00 34.56 !>8.80 160.000 75.000 130.94 854.00 984.84 2.501 1.382 

4.50 2.00 0.07 79.00 6.00 6.00 o.oo 34.56 61.26 160.000 75.000 124.97 854.00 978.97 2.486 1.367 

4.50 2.00 0.87 7S,OO 6.50 6.50 o.oo 34.StS. 63.77 160.000 75.000 120.05 854.-00 974.05 2.473 1.354 

4.50 2.00 0.87 78.00 7.00 7.00 o.oo 34.56 66.32 160.000 75.000 115.90 854.00 969.90 2.463 1.344 

88 CZ698 I6.CLN 
55FR23842. 

Federal Register / Vol. 55, N~.' 113 /Tuesday, Ji'.me 12, 1990 I Rules and Regulations 23879 

Table 13 

GAS WATER HEATER 

(FOAM INSULATION) 

HE!GHT DIAMETER EMIS GALLONS INS TOP INS SIDE IN;i! BO'.\' T~ AREA J. AREA W. TEMP A. TEMP Q LOSS Q ADD Q TOTAL SL SL W/O PI 

(ft) (ft} (in) (in) (in) (sq!t) (sqft) (F) (F) (Btu/h) (Btu/h) !Btu~h) (\/RR) (\/RR) 

-------------------------------------------------~------------------------~-----?-------------~---~---------------------------------------------. 4.50 2.00 0.87 78.00 o.oo- o.oo •' o.oo 34.56 34.56 •156.764 72.566 5367.64 954;00 6221.64 15.949 14.819 

4.50 2.00 0.87 78.00 0.50 0.50 o.oo 34.56 • 36.54 ' 156.764 : 72.566 1052.67 ss4.90 1906.67 4.888 3.758 

4.50 2.00 0.137 78.00 1.00 1.00 : o.oo 34;,55 30.51 '156. 764 72.566 625.31 854.00 1479.31 3.792 2.663 

4.50 2.00 0.87 78.00 1.50 1.50. o.oo 34.56 .40,64 156.764 72.566, 459.08' : 854.00 ' 1313.08 3.366 2.236 

4.50 2.00 0.87 78.00 2.00 2.00 o.oo 34.56 42.76 156.764 72.566 370. 54 954,00 1224.54 3.139 2.009 

4.50 2.00 0.87 78.00 2.50 2.50 .o:oo 34;55 44.92 ' 156. 764 72.566 315.66 854.00 1169.66 2.998 L869 

4.50 2.00 0.87 78.00 3.00 3.00 o.oo 34 ~.56 47.12 '156.764 72.566 277 .23 654.00' 1131.23 2.900 1.770 

4.50 2.00 0.87 76.00 3.50 3.50 0;00 34.56 '49.37 156.764 72.566 '250.56 654.00 1104.56 2.631 1.702 

4.50 2.00 0.87 78.00 4.00 4.00 o.oo 34.56 51.66 156.764 72.566 230.43 854.00 1084.43 2.780 1.650 

4.50 2.00 0.87 78.00 4.50 4.50 o.oo 34;56 54.00 156. 764_ 72.566 214.74 854.00 1066.74 2.740 1.610 

4.50 2.00 O.S7 78.00 s.oo s.oo o.oo ·34,56 56.37 155.764 72.!>66 202.22 854.00 1056.22 2.700 1.578 

4.50 2 .. 00 0.87 78.00 5.50 5,50 o.oo l4,56. '58.80 156. 764 72.566 192.00 '854.00 1046.00 2.681 1.552 

4.50 2.00 0.67 78.00 6.~00 6.00 o.oo 34.56 ; 61.26 '156. 764 72.566 183.56 854.00 1037.56 2.660 ,1.530 

4.50 2.00 0.87 78.00 6.50 6.50 o.oo l4.56 63.77 156.764 72.566 176.48' 854.00 1030.48 2.642 1.512 

"'· 50 2.00 0.07 78.00 7.00 7.00 o.oo 34.56 66.32 156.7~4 72.566 170.48 854.00 1024.48 2.626 1.497 

89 ,. 

BILLIMG COOE 6450-01-C 
 55FR23842

23880 Federal Register / Vol. 55, No. 113 J Tuesday, June 12, 1990 / Rules and Regulations .. 

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of Standards, Washington, DC. 

Vasilakis, A.D., J.F. Peraron, and J. 

Cerstmann. 1980. Research and Development 

of a High Efficiency Gas-Fired Water Heater. 

Volume 1, Final Report Summary, ORNL/ 

Sub-7381/1; and Volume 2. Concept and 

Market Evaluation, ORNL/Sub-7331/2. 

prepared for Oak Ridge National Laboratory. 

Advanced Mechanical Technology, Inc .. 

Newton, MA. 

-. 1988. "Statistical Review of the U.S. 

Appliance Industry", Appliance Magazine, 

Aprii 1988. Vol. 45, No. 4., pg. 56. Dana Chase 

Publications, Inc., Oak Brook, IL. 
 55FR23842

Federal Register / Vol. 55, .No. 113 / Tuesday, June 12, 1990 / Rules and Regulations 23881 

vm. Summary 

The preceding sections of !his 

Response and Announcement represent 

DOE's efforts to provide a thorough and 

subs Ian live response pursuant to the 

final step in the remand procedure set 

for!h in the October 6, 1989, 

Memorandum and Order of the Court in 

Gas Appliance Manufacturers 

Association et al. v. Secretary of 

Energy. Specifically, DOE has provided 

a detailed and substantiated discussion 

of the reasons for and circumstances 

surrounding its adoption of the water 

healer standby loss criteria announced 

today, with attention to the relevant 

statutory requirements, including those 

dealing with practicability, cost-benefit 

analysis and impact on affected groups. 

In that regard, DOE has addressed the 

comments and suggestions submitted by 

interested persons during the remand 

procedure, as well as the results of tests 

and analyses performed in connection 

with its consideration of those 

comment!; and suggestions. 

In conjunction with the publication of 

this Response and Announcement, and 

in further response to the Court's 

Memorandum and Order, DOE has· also 

placed in the public rulemaking record 

all of the technical support documents 

and referenced materials upon which it 

relied in reaching the decisions 

discussed in the preceding sections. 

List of Subjects in 10 CFR Part 435 

Architects, Building code officials, 

Buildings, Energy conservation, Energy 

conservation building performance 

standards, Engineers, Federal buildings 

and facilities. Housing, Water heaters, 

Insulation, and Voluntary performance 

standards. 

With due consideration of the 

comments that have been received and 

the results of further tests and analyses 

that DOE has caused to be conducted, 

and in accordance vvith the remand 

procedure provided for in the Court's 

October 6, 1989, Memorandum and 

Order, DOE is announcing and adopting 

the water heater standbv loss criteria 

set forth in Table 9.3-1 ~hove (part 435 

of chapter II of title 10 of the Code of 

Federal Regulations subpart A, 

§ 435.109, Table 9.3-1, Standard Rating 

Conditions and Minimum Performance 

of Water Heating Equipment). 

Issued in Washington. DC, on June 7, 1990. 

J. Michael Davis, 

Assistant Secretary, Conserv-ation and 

Renewable Energy. 

[FR Doc. 90-13661 Filed 6-8-90; 4:31 pm] 

SIU.ING CODE 6450-01-M