DESIGN AND EVALUATION CRITERIA

FOR ENERGY CONSERVATION

IN NEW BUILDINGS

NBSIR 74-452

February 27, 1974

Revised February 26, 1976

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

V\^hingloa D.C. 20234

FYepared for:

NATIONAL CONFERENCE OF STATES

ON BUILDING CODES AND STANDARDS

February 27, 1974

U.S. DEPARTMEIUT OF COMMERCE

National Bureau of Standards

Washington, D.C. 20234

National Conference of States for

Building Codes and Standards

c/o Mr. Bernard E. Cabelus, Chairman

State of Connecticut Delegate

State Office Building

Hartford, Connecticut 06115

Dear Mr. Cabelus:

The "Design and Evaluation Criteria for Energy Conservation in New

Buildings" was developed in response to the July 12, 1973 request

of the National Conference of States on Building Codes and Standards

to provide the technical basis for a performance-type standard.

Although this document is comprehensive in its technical scope, it

is not practical at this time to develop a single document which would

be universally applicable to all types of buildings in a uniform

manner.

It is our recommendation that this document be used as the basis for

the development of a consensus standard to apply to new construction

for all building types except those excluded in the following paragraph.

It is also our recommendation that the, States be advised not to use the

document in its present form for regulatory purposes.

The following recommendations are made with respect to:

1. Residential buildings including manufactured housing (oneand two- family) —

" The Federal Housing Administration's Minimum Property

Standard 51b should be used as an interim standard.

** A consensus standard for one- and two-family housing

should be developed using this doctament as a guideline

to expand the scope covered by MPS 51b. It should include

such factors as: air infiltration, usage of glass,

illumination levels, and electrical distribution systems.

It should seek to eliminate wasteful practices in heating,

ventilation, air conditioning, and service water systems.

** As an interim measure, the States should investigate the

possibility of initiating a voluntairy labeling program

for buildings which meet the requirements of this document.
2

2. Mobile Homes —

** The Coordinating Committee of the National Mobile Home

Standard should be requested to sponsor and appoint a new subcommittee to develop an energy conservation

supplement to ANSI A119.1. This supplement should be

completed by July 1, 1974, using this doctjment as a guideline.

3. Industrial buildings, monument buildings, short-term periodic

use buildings such as vacation shelters, or buildings containing special laboratories —

" Instead of using this document, special energy conservation

measures applying to these buildings should be developed

which take into consideration the special conditions which

prevail.

As indicated in your November 19, 1973 letter to Dr. Richard Roberts,

Director of the National Bureau of Standards, performance standards

cannot be utilized without changes in the structure of the building

regulatory system. It is recoiranended that NCSBCS at its February 27, 1974

meeting study what tasks need to be done to make performance standards

workable and designate appropriate organizations to carry out the

identified tasks. The completion of these tasks should be scheduled

so that the regulatory system is capable of handling a performancetype standard when the consensus standard based on this document has

been completed.

Sincerely

,

F. Karl Willenbrock, Director

Institute for Applied Technology
NBSIR 74-452

DESIGN AND EVALUATION CRITERIA FOR

ENERGY CONSERVATION IN NEW

BUILDINGS

Jim L. Heldenbrand, Editor

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

February 27, 1974

Revised February 1976

Prepared for National Conference of States on Building Codes and Standards

U.S. DEPARTMENT OF COMMERCE, Elliot L Richardson, Secretary

James A. Baker, III, Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

FOREWORD

This docToment is a set of design and evaluation criteria for energyconservation in most types of new "buildings. The National Conference of

States on Building Codes and Standards (NCSBCS) requested that the National

Bureau of Standards (NBS) develop such a document with the intent that it

covild serve as a basis for a national standard developed through the

voluntary consensus process.

Development of these design criteria required engineering value judgments

in their preparation. Two Administration energy policy directives have

served as quantitative goals for the engineering judgments that guided

the formulation of these criteria: these are found in the President's

1971 and 1972 Energy Messages to Congress. In 1971* the President directed the Secretary of Housing and Urban Development to reduce maximum

permissible energy loss by "about one-third for a typical 1200 square foot

home—and by even more for larger (federally insured) homes," In the

following year, the President directed the Secretary to "issue revised

insulation standards for apartments and other multifami ly structures not

covered by the earlier revision. The new rules will cut maximiam permissible (energy) loss by hO percent," A third Administration statement

appeared part way through the criteria's development which reinforced its

conservation orientation. This was Atomic Energy Commission Chairman

Dixy Lee Ray's report to the President (December 1, 1973) on a plan to

commit $10 billion to Federal energy research and development in fiscal

1975-79. In that report, entitled The Nation's Energy Future , conservation is central to the Federal Government's energy self-sufficiency

strategy. Moreover, the Ray report ranks conservation of energy as the

highest federal research and development priority.

The design and evaluation criteria focus on building subelements and ser- vice system arrangements. Special provisions offer added flexibility for

both conventional and innovative designs. The technical portions of the

document are organized into four complementary sections: requirements,

criteria, evaluation and commentary. Existing standards and procedures

promulgated by organizations such as the American Society of Heating,

Refrigerating and Air Conditioning Engineers (ASHRAE), the American

Society for Testing and Materials (ASTM) and the American National Standards Institute, Inc. (ANSI) are referenced whenever possible. The

evaluation statements describe how to verify that candidate solutions

meet the stipulated criteria. Finally, the commentary statements convey

the intent of the criteria and, in a number of cases, explain how the

criteria were selected.

We believe adherence to the criteria contained herein will result in

significant energy savings while maintaining an acceptable level of

habitability , thus advancing several national goals.

Paul R. Achenbach,

Chief

Building Environment Division

Center for Building Technology, lAT

National Bureau of Standards

February 27, 197^
DESIGN AND EVALUATION CRITERIA FOR

ENERGY CONSERVATION IN NEW BUILDINGS

CONTENTS

Page

Foreword i

Task Group for Development of the Energy Doctiment—^ iii

Background of Project 1

Procedures Used in Development of the Energy Document 2

Application 4

Design Criteria with Evaluation and Commentary Statements 6

Chapter 1. Objective 7 2 . Scope 8

3. Definitions 9

4. General Performance Requirements 13

5. Exterior Envelope Requirements 14

Appendix 1 Examples Illustrating the

Application of Chapter 5 Criteria 32

Appendix 2 Heat Flux, Thermal Resistance and Thermal Transmittance Values

for Ceilings, Roofs, and Opaque Walls 47

6. Heating, Ventilating and Cooling System

Requirements 53

Appendix 1 Listing of Standards for

HVAC Equipment Which Include Efficiency 73

Appendix 2 Procedure for Determining

Coefficient of Performance (COP), 6.5.8 75

7. Service Water Heating Requirements 76

Appendix 1 Listing of Standards for

Service Water Heating Equipment Which

Include Efficiency 78

8. Electrical Distribution and Power-Factor

Requirements 79

9. Lighting Requirements 82

10. Energy Requirements for Building Designs

Based on Dynamic Analysis 86

11. Requirements for Buildings Utilizing Solar

or Wind Powered Energy Sources 89

Conversion Factors to Metric (SI) Units 93

Procedure for Determining Economic Efficiency 95

New Information Needed for Energy Conservation Criteria 96

Wherever the term "document" is used in this publication it refers to

these design and evaluation criteria unless the immediate context indicates another meaning.

ii
TASK GROUP FOR DEVELOPMENT OF ENERGY DOCUMENT

The energy document is the result of work by personnel of the National

Biireau of Standards Center for Building Technology aiigmented by a group

of advisors who met frequently over a period of three months. The following persons comprised the Task Group.

Paul R. Achenbach, Program Manager, Task Group for Energy Document

Jim L, Heldenbrand, Project Manager

Robert W. Beausoliel

Adolfo A. Camacho

Peter F. Colwell

James E, Hill

Tamami Kusuda

Charles T. Mahaffey

Bradley A, Peavy

Clinton ¥. Phillips

Frank J, Powell (Chief, Thermal Engineering Systems Section)

Jack E, Snell (Ass't Chief, Building Environment Division)

Francis T, Ventre (Ass't Chief, Office of Building Standards and Codes

Services

)

Thomas W, Watson

Gary Yonemura

NBS CENTER FOR BUILDING TECHNOLOGY

ADVISORS* DESIGNATED BY

Samuel A. Bogen

Bogen Jenal Engineers, P.C.

Albert son. New York

American Consulting Engineers

Council (ACEC)

Joseph A, Demkin

Dept. of Professional Practice, AIA

Washington, D. C.

American Institute of Architects

(AIA)

Charles A, Hagberg

Hagberg and Associates

Madison, Wisconsin

National Conference of States on Building Codes and Standards

(NCSBCS)

Lawrence G, Spielvogel

Lawrence G, Spielvogel, Inc.

Wyncote, Pennsylvania

American Society of Heating,

Refrigerating, and Air Conditioning Engineers (ASHRAE)

Joseph Stein

Tishman Research Corp.

New York, New York

National Conference of States on Building Codes and Standards

(NCSBCS)

*Participation in the preparation of this doctmient does not imply endorsement by the advisors or the organizations who designated them.

BACKGROUND OF PROJECT

Temporary shortages of gas, oil, and electricity have occurred during the

last two years in various areas of the country. These shortages have

caused temporary shutdowns of schools, offices, manufacturing, food processing, and military installations, and brought about requests to State

and City executives for guidelines in the use of energy resources. Several State governments have initiated independent legislative action to

control the use of limited energy resources in new buildings, thus raising

the possibility that a wide variety of different requirements could be

imposed on the building and equipment industries.

In an effort to provide uniformity in the requirements placed on building

design by the various State and local governments, the National Conference

of States on Building Codes and Standards (NCSBCS) in July 1973 requested

the National Bureau of Standards (NBS) to develop an interim standard for

energy conservation in new buildings which would be available for consideration by the States during their 1973-7^ legislative sessions. Although

NBS does not promulgate or establish engineering Standards— , it strongly

supports the concept of voluntary consensus standards, NBS agreed to

develop design and evaluation criteria for energy conservation in new

buildings which would be made available to a suitable organization for

sponsorship through the consensus process. Toward this end NBS prepared

alternative plans for expeditiotis promulgation of their criteria through

the consensus process by such a sponsor.

NBS established a Task Group in the Center for Building Technology to

develop the document. With the concurrence of NCSBCS, NBS invited three

professional societies who are concerned in a broad way with the design

of buildings and energy-using equipment, and NCSBCS itself to name advisors

to work with the NBS Task Group. After receiving a preliminary draft,

ASHRAE has offered to sponsor this docment throiigh to a national consensus volimtary standard. NCSBCS will act on this proposal at their

meeting in Salt Lake City on February 27, 197^.

"TJ Exceptions to this generalization are the voluntary product standards

and the limited number of mandatory standards covered by Congressional

directives.

1
PROCEDURES USED IN DEVELOPMENT OF THE DOCUMENT

NCSBCS requested that the document he performance oriented where practicahle. Since the term "performance" is subject to various interpretations,

a number of different approaches were studied. The following two categories

of objectives for the energy document were developed by NBS and approved

by NCSBCS, and the various performance approaches were rated for their

ability to attain these objectives:

ESSENTIAL OBJECTIVES

1. Be available by January 197^.

2. Effect significant energy savings,

3. Be applicable to a range of building construction, occupancies,

climates, and equipment,

h. Be amenable to consistent interpretation,

5, Be compatible with existing health, safety, and environmental

regulations,

6, Be useful as a design guide,

7. Be an improvement over existing dociments,

8. Merit a high level of voluntary compliance,

DESIRABLE OBJECTIVES

1. Maximize energy savings,

2. Be an acceptable basis for a voluntary consensus standard,

3. Reflect due consideration of cost implications,

h. Permit design flexibility and choice of materials and equipment

within given constraints.

5, Maintain acceptable standards of space, environmental conditions,

and convenience,

6, Clearly differentiate requirements for each type of occupancy,

7, Suggest methods of preconstruction evaluation,

8, Include provision for different (emergency) conformance levels.

2
The approach -which rated the highest probability of attaining the above

objectives can be described as a "framework of performance statements

supported by performance requirements for subelements and vas followed

in preparing this document.

The timeframe within which the document was developed permitted the use

of state-of-the-art technology only. A public workshop was held on November 12 and 13, 1973, after annoimcement in the Commerce Business

Daily and the issuance of written invitations to State officials and to

a broad selection of professional and industrial associations for its

provisions. During the preparation of this document, meetings were held

at NBS between the Task Group and officials of various industry associations representing types of energy resources, mechanical equipment for

buildings, the housing and mobile home industries, and building materials,

to obtain their views and recommendations of building requirements.

In advance of making the resiilting design and evaluation criteria available

for sponsorship through a consensus review process an opportunity was provided to selected industry, professional and government groups to review

a working draft. In addition NBS contracted for economic and technical

impact analyses of the draft document from nine architectural and engineering firms and industry associations. These comments and analyses

have received consideration in the preparation of this document.

Design requirements were developed for only those features of energy-using

equipment for which enoiigh technical information was available to support

a definitive criterion. Other parameters can be covered now by guidelines

to designers on an advisory basis, and may be incorporated into future

revisions of the document as the experience and technology of energy con- servation expands.

3
APPLICATION

As illustrated in Figure 1, the dociiment provides three paths to acceptance of a building's design energy requirement. Path 1 is basic since it

provides the most direct approach and also provides the basis of comparison

for establishing acceptable levels of energy usage for the alternative

approaches afforded by Path 2 and Path 3.

By choosing only Path 1 in Figure 1, the building designer chooses to

comply -with the performance statements of Chapters 5 through 9 of this

document These chapters contain a set of detailed performance requirements and criteria directed toward the saving of energy through design of

building envelopes with good thermal resistance and low air leakage, and

utilization of energy-saving practices in the design of mechanical and

electrical systems. Provisions for acceptance of alternative designs for

the building envelope are also included in Chapter 5. Conformance with

Chapters 5 through 9 will result in energy conservation in buildings, and

will provide design guidelines suitable for most building applications

without the necessity for analysis of annual energy use.

In choosing Path 2 in Figure 1, the designer must perfonn a dynamic energy

analysis on the building and service systems selected in Path 1. The re- sulting computed annual energy consumption becomes a reference energy

budget. An alternative building design which does not necessarily meet

each and every subelement requirement will be acceptable if an energy

analysis of that design shows that the calculated annual energy use is

equal to or less than the reference energy budget. Details regarding the

Path 2 approach are given in Chapter 10 and illustrated in Figure 10-1,

Path 3 provides the designer with an allowable increase in total design

annual energy consumed by the total building system, as a bonus for

substituting solar or wind powered energy for part or all of the energy

otherwise generated from mineral energy sources such as fossil fuel and

uraniixm. The reference energy budget is based on a building designed

to meet the requirements of Path 1, The basis for claiming an energy

bonus is a dynamic energy analysis to establish both the reference energy

budget and the annual design energy contribution provided by the solar

or wind powered energy source. Details regarding the Path 3 approach

are given in Chapter 11 and are illustrated in Figure 11-1 and the Commentary on Chapter 11,

l7 Chapters 1 through k apply to all three paths.

4

DESIGN CRITERIA WITH

EVALUATION AND COMMENTARY STATEMENTS

The Requirement and Criteria statements contained in this document are supplemented vhere necessary vith Evaluation and Commentary statements.

The Evaluation statements are intended to identify suggested procedures

for evaluating a building design for conformance vith the Criteria, The

Commentary statements provide examples and sample calculations to illustrate design options and procediires and, in some instances, provide

rationale for the Criteria.

Where no Evaluation or Commentary statement is given, the Criteria statement

is presumed to be self-explanatory.

6
CHAPTER 1

OBJECTIVE

These design and evaluation criteria contain performance-oriented re- quirements for energy conservation in buildings. This document— was prepared in response to a request by the National Conference of States , on Building Codes and Standards to the National Bureau of Standards.

It is intended to be the forerianner of a consensus standard to be

promulgated by a national standards organization.

The document is performance-based to the extent permitted by present

building design technology. The performance concept is applied at the

subelement or subsystem level to synthesize an energy-efficient total

system. The detailed performance requirements and criteria are directed

tovard the design of building envelopes with good thermal resistance and

low air leakage, and toward requiring practices in the design of mechanical

and electrical systems which conserve energy. Design flexibility is

achieved by providing for acceptance of alternative design solutions that

can be shown to save equivalent amounts of energy without following each

and every detailed requirement. Such alternative designs, as well as those based on subelement requirements, must be supported by drawings,

specifications, and calculations to demonstrate compliance.

The draft design and evaluation criteria can be made effective only by

the application of its provisions in the design process, by review and

evaluation of design proposals, and by the inspection of resulting con- struction. It is not the intent of this document to require tests and

measurements of the completed building and its service systems to demonstrate compliance with its provisions except where explicitly stated.

1/ Wherever the term "document" is used in this publication, it refers

to these proposed design and evaluation criteria unless the immediate

context indicates another meaning.

7
CHAPTER 2

SCOPE

These design criteria are applicable to the design and construction of

most new buildings for hman occupancy except to buildings or portions

thereof that are primarily an envelope over an industrial process; to

buildings designed as monuments, to buildings intended for short-term

periodic use, such as vacation shelters, or to portions of buildings

containing special laboratories.

It is the intent of these design criteria to cover principally the features

of a building and its equipment that determine its use of energy, and is

not intended to abridge any safety or health requirements. The operation

and use of buildings is not covered by this docijment, although some of

the equipment requirements will inherently promote more efficient

operation.

8
CHAPTER 3

DEFINITIONS

The folloving definitions are stipulated for the pui^oses of this document:

Building — Any combination of materials, whether portable or fixed, which

comprises a structure affording facilities or shelter for assembly, education, business, mercantile, institutional, or residential occupancies,

as well as those portions of factory and industrial, and hazardous and

storage occupancies which are used for office space. The word building

shall be construed herein as if followed by the words "or part or parts

thereof and all energy-significant equipment therein" unless the context

clearly requires a different meaning. Unless otherwise stipulated, the

term buildings as used in this doctunent includes mobile homes and manufactured buildings.

Coefficient of Performance (COP) — For cooling systems , the ratio of

the rate of net heat removal to the rate of energy input, in consistent

units. For heat pumps in the heating mode, the ratio of the rate of

heat delivered to the rate of energy input, in consistent units.

Engineered System — A system assembled at the point of application

largely from standard components and packaged subsystems to meet a unique

set of design requirements for a specific application, as contrasted with

a mass produced system identified and so].d as an integral product

identified by a model number.

Energy Converting Equipment — Equipment used principally to convert energy

from one form to another, such as furnaces, electric motors, etc.

Energy Processing Equipment — Equipment used principally to exchange

energy, such as condensers, heat exchangers, etc. Specifically excluded

are piping, ducting, and electrical distribution components,

Energy-Significant Equipment — Means (l) central, unitary, or room space

conditioning equipment , including but not limited to energy converting/

processing equipment used in engineered systems and energy converting/

processing packaged subsystems, and (2) service water-heating equipnent.

Full-Load Energy-Utilization Efficiency (n//?) — The energy-utilization

efficiency of energy-significant equipment , when operated at full-load

rated capacity, computed as a ratio of useful output divided by energy

input, including any auxiliaries, and converted to a percentage figure,

as follows:

= Output (icq), percent.

Thermal Input x C + Electrical Input x C

9
Where: Output = Useful effect (e.g., heating or cooling, shaft output

energy, moisture added or removed, etc.) converted to Btu/hr.

Thermal Input = Thermal equivalent input of energy to direct

fired equipment, in Btu/hr.

Electrical Input = Input to electrically energized equipment or components of equipment, in kw,

= 1.15 for off-cycle draft ( exfiltration) losses on fuel

burning equipment lacking devices to minimize air flow through

the combustion chamber during burner off-cycles. = 1.0 for

equipment utilizing such controls.

= 12,000 Btu/hr (k"w) for electrical generation and transmission to load.

HVAC System — A system that provides either collectively or individually

the processes of comfort heating, ventilating, and/or cooling within or associated with buildings.

Manufactured Building —- Any building which is of closed construction

and which is made or assembled in manufacturing facilities, on or off

the building site; also any building of open construction for which

certification under this document is sought by the manufacturer and which

is made or assembled in manufacturing facilities away from the building

site for installation, or assembly and installation on the building site.

The term does not mean "mobile home."

Mobile Home — A factory-assembled, movable dwelling designed and con- structed to be towed on its own chassis, comprised of frame and wheels,

usually used without a permanent foundation, and distinguishable from

other types of dwellings in that the standards to which it is built include provisions for its mobility on that chassis as a vehicle.

New Energy — Energy obtained by increasing the output of the basic

energy conversion process as contrasted to energy recovered from or wasted by a primary energy-utilization system.

Opaque Areas — All exposed areas of a building envelope which enclose

conditioned space, except openings for windows, skylights, doors, and

building service systems.

Recovered Energy — Energy utilized which would otherwise be wasted (or

rejected) from an energy-utilization system.

Reheat ~ Sensible heat added to condition a zone to overcome cooling

produced by expenditure of energy within the HVAC system serving that

zone.

Solar Energy Sources — Sources of thermal or photoelectric energy derived

directly from conversion of incident solar radiation.

10
Test Year — A year of hourly weather data recommended hy the ASHRAE

Technical Committee on Weather Data and Design Conditions for the purpose of energy consmption analysis. It is a weather year chosen from

past weather in a given locality in terms of frequency, duration, and

severity of hot and cold spells and in terms of overall energy requirements for heating and cooling buildings. In the absence of ASHRAE

recommendations the designer may designate a test year for the locality

concerned.

Thermal Break — A relatively poor conductor of heat used to interrupt

the path of heat flux between the inner and outer surfaces of a building

element

,

Total Energy System — A system in which electric power is generated on

or near the building site by means of engines or turbines, with exhaust

and jacket heat recovered and used for space heating, water heating,

absorption air conditioning, and/or process applications. For the purposes of this document, a qualifying total energy system shall have a minimum annual energy-utilization efficiency of 50 percent, including

energy inputs to necessary auxiliary equipment. Combination electric

generating and district heating or district cooling plants which have a minimum annual energy-utilization efficiency of 50 percent are also defined as total energy systems for the purpose of this document,

Unheated Space — Means a ventilated crawl space, an unheated attic,

basement or garage, or the outdoors, A basement or unheated portion

thereof within which a heating system is located, shall be considered

heated space if no insulation is provided at the basement ceiling, and

shall be considered vinheated space if insulation is provided at the basement ceiling. In mobile homes, spaces shall not be considered unheated

which fall within an insulated envelope which provides one-half or more

or the total resistance to the flow of heat, as required by Chapter 5.

Unitary Air Conditioner — Means one or more factory made assemblies

which normally include an evaporator or cooling coil, a compressor and

condenser combination, and may include a heating function as well. Where

such equipment is provided in more than one assembly, the separated

assemblies are to be designed to be used together.

Zone — With respect to the temperature control requirements in this document, a zone is defined as a portion of the space within a building which,

recognizing the nature of its heating/cooling loads, could be satisfactorily

controlled to desired temperature limits imder varying outdoor conditions

by the operation of a single automatic temperature control at an appropriate location within the zone. For actual temperature control criteria,

refer to 6,h,2 and 6.U.3.

11
COMMENTARY

Fiill-Load Energy Utilization Efficiency —- This definition is provided in

conjunction with paragraphs 6,3 and 6,h to give system designers an interim

basis for selection of efficient equipment. Efficiency information is

needed for design of efficient systems, regardless of the nature of the

energy source. Under the section on "New Information Needed for Energy

Conservation Criteria" it is recognized that part-load efficiency data are

not widely available at present for all types of energy-significant

equipment, A requirement for part-load efficiency data should be incorporated in the criteria as soon as standard test procedures can be developed, in order to a) refine energy calculations affecting the design and

selection of systems and equipment, and b) to avoid competitive pressures

to optimize equipment efficiency at a load condition (such as 100^ of

design-rated load) which may not be typical of seasonal operation.

Referring to the constants used in the definition for Full-Load EnergyUtilization Efficiency, it is recognized that there are different values

for energy conversion and transmission processes using direct-fired

equipment. Because these factors are not all well docijmented at the

present time, and because the order of magnitude of their values is

nearest to unity, a value of one is assigned to C^, Where off-cycle

exfiltration is a factor, a 15-percent loss is assigned, pending receipt of better data. The C^ figure of 12,000 Btu/kw hr was computed

from national fuel consumption and energy production figures based on "Electric Power Statistics," Federal Power Commission, 1972, romded

to the nearest 1,000, It is necessary to use constants representing

national averages to simplify the manufacturer's task of answering

requests for the efficiency information stipulated in 6,h or of publishing such data in sales literature or catalogs. This approach

provides a simple yet fair method of including relative comparisons of

efficiency among the considerations for deciding between competitive

equipment

,

12
CHAPTER k

GENERAL PERFORMANCE REQUIREMENTS

The following general performance requirements shall be the basis for the

more detailed statements of requirements and criteria which make up this

perfonnance document.

U.O REQUIREMEaJT

Buildings and their service systems shall be designed to use energy

efficiently while maintaining an acceptable thermal and visual environment and preserving their essential functional characteristics. The

constraints put on energy use shall allow flexibility in the choice of

materials and subsystems in the design process,

k,l REQUIREMENT

The thermal resistance and air tightness of the exterior envelope of a building shall be designed to conserve energy under the applicable

climate and occupancy conditions.

k,2 REQUIREMEJTT

The service systems in buildings used for heating, cooling, ventilation,

domestic water heating, and lighting shall be designed for the efficient

use of energy whether the energy conversion to useful effect occurs in

the building or at some other location,

1^,3 REQUIREMENT

Waste heat shall be recovered for useful purposes wherever practicable.

13
CHAPTER 5

EXTERIOR ENVELOPE REQUIREMENTS

5.0 REQUIREMENT

A building which is heated or cooled for comfort purposes shall be designed

to restrict the flow of heat through the building exterior envelope,

CRITERIA (DESIGN CONDITIONS)

5.0,1 Combined Heating/Cooling A building designed to be both heated

in winter and cooled in summer shall meet the higher of the summer and

winter thermal resistance values for ceilings and roofs, opaque walls,

foundation walls, slabs-on-grade, and the air leakage criteria requiring

the greater airtightness . The winter design criteria shall be used to

determine the area, heat transmission factors, and air leakage of doors

and windows; water-vapor condensation control, and properties of caulking

and sealants. The summer design criteria shall be used to determine

shading requirements for windows. The preceding guidelines for selecting

design criteria shall apply when establishing the reference energy budget

for comparison with alternative designs provided for in Chapters 10 and 11.

EVALUATION

The design requirements for heating and cooling will be compared,

where appropriate, to select the criteria which require the greater

insulation resistance and airtightness.

COMMENTARY

This criterion is provided to require the designer and evaluator to

design to the greatest need. For example, buildings in warm climates

should restrict heat gain to minimize cooling loads, while buildings

in cold climates should restrict heat loss to minimize heating loads.

This criterion also requires more insulation in the coldest climates

where it is most needed.

5.0.2 Design Temperatures -- For the purpose of determining the thermal

resistance to the flow of heat, indoor and outdoor design temperatures

shall be used as specified below and in the ASHRAE Handbook of Fundamentals, 1972.

CRITERIA

Design Temperatures, dry-bulb, "F

Indoor Outdoor"

Heating

Cooling

70 ''F Heating

78 **F Cooling

- see Column 4, subheading 97-1/2%

- see Column 6, subheading 2-1/2%

* See next page.

14
* For locations in the United States and Canada, values given in

Table 1, page 669, 1972 American Society of Heating, Refrigerating

and Air Conditioning Engineers (ASHEAE) Handbook of Fundamentals,

shall be required.

EVALUATION

Engineering examination of design temperatures used in calculations,

CRITERIA (HEATING)

5.0.3 Opaque Ceilings /Roof - Heating The heat flow through opaque

areas of roofs or ceilings facing heated interiors shall not exceed the

values of q/A (Btu/hr ft of ceiling area) given in Table 5.1 for regions

classified by heating degree-days when calculated at the indoor and outdoor design temperatures specified in 5.0.2.

q/A = U(t^ - t^) (1)

(2)

1 o

2 where q/A = heat flux, Btu/hr ft . U = overall coefficient of heat transmission or thermal transmittance, air to air, Btu/hr ft "F.

t, = indoor design temperature, "F.

t^ = outdoor design temperature, "F.

5.0.3.1 Degree-day Values -- For locations in the United States and

Canada, yearly total heating degree-days values given in Table 2, page

433, American Society of Heating, Refrigerating and Air Conditioning

Engineers 1973 Systems Handbook shall be required. For degree-day values

falling between the values tabulated in Table 5.1, intermediate values

of q/A for ceilings and roofs may be read from Figure 5.1.

Table 5.1

Maximum Heat Flow Through Opaque

Areas of Roofs or Ceilings at Design Conditions

Heating

2 Degree-days q/A, Btu/hr (ft Roof or Ceiling Area)

0 4.2

1,000 3.7

2,000 3.5

3,000 3.5

4,000 3.-5 5,000 3.5

6,000 3.5

7,000 3.6

8,000 3.6

9,000 3.7

10,000 3.8

12,000 4.0

14,000 or greater 4..4

15

EVALUATION

Engineering examination and evaluation of heat flow computations or test results. Design values of the thermal resistance of building

materials as given on pages 357-363, ASHEAE 1972 Fundamentals Volume shall be used for evaluation,

COMMENTARY

A limit is placed on the heat flow through ceiling surface areas.

The required overall thermal resistance of the ceiling/roof con- struction for each geographic area of the U. S. can be determined

by the procedure used in the illustrative examples given in Appendix 1 to Chapter 5. A plot of q/A vs Heating Degree-days is shown

in Figure 5.1. Design values of the thermal resistance of building materials to be used for evaluation are given on pages 357-363,

ASHRAE 1972 Fundamentals Volume.

Heating energy used in a building correlates more closely with heating degree days than with design temperature difference. Degree

days are not precisely related to design temperature differences

referenced in handbooks. Therefore the criteria for heat flux

through building elements was made to correlate with heating degree

days and the thermal resistance was adjusted to meet the heat flux

criteria at design temperature conditions. A building in a city

having a greater design temperature difference but the same degree

days as for an identical building in another city will have greater

thermal resistance. This will result in somewhat less annual energy

usage. The rationale for this approach is to maintain approximately

equivalent comfort conditions for cities having lower extremes of

design temperature.

CRITERIA

5,0.4 Gross Exterior Walls (Including Opaque Wall, Window, and Door Areas - Heating -- The combined thermal transmittance value (U value) for the gross area of exterior walls consisting of opaque wall areas, window areas, and

door areas, all facing a heated interior, shall not exceed the values given

in Table 5.2 for regions as classified by heating degree-days (see 5.0.3.1)

when calculated at the indoor and outdoor design temperatures specified in

5.0.2. For degree-day values falling between the values tabulated in

Table 5.2, intermediate values of the combined thermal transmittance of

exterior walls, U^, shall be read from Figure 5.2.

Table 5.3 provides guidelines for using equation (3) to select combinations of opaque wall, fenestration, and door areas and thermal resistances

to satisfy the requirements of Table 5.2. The thermal transmittance values

for window areas and door areas, and the amount of wall, window, and door area and its distribution in the periphery of the exterior walls of the

building are at the option of the designer, providing the criteria for combines thermal transmittance are satisfied. For additional options see 5.0.9. For degree-day values falling between the values tabulated in

Table 5.3, intermediate values of q/A for opaque walls shall be read from

Figure 5.1.
Table 5.2

Uq Values, Gross Exterior Wall Area, Btu/hr ft^ "7

neadug One- and Two -Family All Other

Degree-days Living Units and Mobile Homes Buildings

ou n fin vj . DJ

J uu n AS n "^1

1J. nnrt

f uuu 0U "^fi

. J D nU .tuAr> 0.29 0.37

0.27 0.36

0.25 0.34

J f uuu 0.22 0.32

O J ^ J u 0.20 0.30

7 1^00

/ , juu 0.18 0.28

10 000 0.17 0.27

12,000 0.16 0.26

Table 5.3

Guidelines for Maximum Heat Flow Through

Opaque Areas of Walls at Design Conditions

Heating q/A,

^ Degree-days Btu/hr (ft Opaque Wall Area)

0 5.0

1,000 4.5

2,000 4.3

3,000 4.3

4,000 4.3

5,000 4.4

6,000 4,5

7,000 4.8

8,000 5.0

9,000 5.3

10,000 5.6

12,000 5.9

14,000 6.0

For convenience of the user of this document, the heat flux (q/A),

thermal resistance (R), and thermal transmittance (U) values meeting

the design criteria of Tables 5.1 and 5.3 for 243 U. S. cities are tabulated in Appendix 2, along with corresponding degree-day and winter

design temperature data from the ASHRAE Fundamentals and Systems Volumes

1972 and 1973, respectively

.

18
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The following formula shall be used to determine acceptable combinations

of wall, window, and door areas, and thermal properties to meet the

requirements of Table 5.3.

UA=U-,A.. + U., A., +U, A,

o o wall wall window wxndow door door (3)

where: U = the average thermal transmittance of the gross wall

° area and A = a unit area of gross wall

o U = thermal transmittance of opaque wall area

wall

" A -, -, = ratio of opaque wall area to gross wall area

wall

U.J = thermal transmittance of window window

A . , = ratio of window area to gross wall area window

U , = thermal transmittance of door

door

A, = ratio of door area to gross wall area,

door

EVALUATION

Engineering examination and evaluation of overall U -value computations. Design values of the thermal resistance o? building materials, thermal transmission for windows and slab doors as given on

pages 357-363, Tables 8 and 9 on page 370, ASHRAE Fundamentals

Volume, shall be used for evaluation.

COMMENTARY

A limit is placed on the thermal transmittance (U - value) of the

gross wall area around the periphery of the building, including the

wall, window and door areas. The required thermal transmittance

for the gross wall area for each geographic area of the U, S. can

be determined by the procedure used in the illustrative

examples given in Appendix 1 to Chapter 5, A plot of U vs Heating

Degree-days is shown in Figure 5.2. Design coefficients of thermal

transmission for windows and slab doors are given in Tables 8 and 9,

respectively, on page 370 of the ASHRAE 1972 Fundamentals Volume

and for the thermal resistance of building materials on pages 357-363.

All of the thermal resistance values required by Tables 5.1, 5.2,

and 5.3 can be met throughout the United States, except Alaska,

without using oversized studs and joists, by using available plastic

or dense fibrous insulation.

The objective of Table 5.3 is twofold: (1) to provide criteria for

designers wishing to prepare energy conserving designs without performing the trade-off analysis permitted in applying Table 5.2 and

paragraph 5.09; and (2) to simplify the first trial step of a

20
trade-off analysis for those designers using the alternative criteria

of Table 5.3 or paragraph 5.9.9. The thermal resistance of the

opaque wall construction for each geographic area of the U. S. can be determined by the procedure used in the illustrative examples

given in Appendix 1 to Chapter 5. A plot of q/A vs Heating Degreedays is shown in Figure 5.1.

CRITERIA

5.0.5 Floors, Foundation Walls, and Slabs-on-Grade - Heating

Floors/Heated Spaces — For floors that face heated areas both above

and below the floor line, there is no requirement for thermal resistance

of the floor area, except that the peripheral edges of the floor must

contain thermal resistance equivalent to that of the thermal transmittance

values of Table 5.2 for Gross Exterior Wall Area above or below the floor

and the thermal resistance must be continuous vertically. If the above

thermal resistance criteria for the peripheral edge of a conventional

structural floor system cannot be met, the peripheral edge shall be

considered a part of the gross exterior wall area which is to be designed

to meet the combined thermal transmittance values in Table 5.2.

Floors /Unheated — For floors that face unheated spaces, the required

maximum thermal transmittance is given in Table 5.4. For degree-day

values falling between the values tabulated in Table 5.4, intermediate

values of the maximum thermal transmittance, U, shall be read from

Figure 5.2.

Table 5.4

Maximum Thermal Transmittance (U-Value)

for Floors Facing Unheated Spaces

Heating Maximum U-value.

Degree-days Btu/hr ft2 °F

0 no requirement

500 0.23

1,000 0.21

2,000 0.18

3,000 0.16

4,000 0.14

5,000 0.11

6,000 0.09

7,000 0.08

8,000 or greater 0.07

Foundation Walls — Foundation walls and the windows and doors therein

enclosing heated space and exposed to outdoor air shall contain thermal

resistance equal to that required for gross exterior walls as specified

in 5.0.4. The thermal resistance of foundation wall enclosing heated

space below grade shall be not lower than 50% of that required for gross

exterior walls above grade. 6 21
Slab-on-Grade For slab-on-grade floors the thermal resistance of the

insulation around the perimeter of the floor shall be equal to 50% of

the thermal resistance of the opaque wall area above the floor

and shall extend downward below the grade line to the footing or the

design frost line, or an equivalent distance horizontally inward from

the edge under the floor.

EVALUATION

Engineering examination and evaluation of U-value and thermal resistance computations. Design values of the thermal resistance of building materials to be used for evaluation are given on pages 357-363,

ASHRAE 1972 Fundamentals Volume.

COMMENTARY

Heated space is considered to be space that is heated for human

occupancy or for prevention of physical damage from freezing. The

meaning of "unheated space" is given in Chapter 3, Definitions.

The "U" value approach is used for Table 5.4, rather than q/A,

because the temperature difference at design conditions across floors

over unheated spaces is more uncertain than the design indoor-outdoor

temperature difference.

CRITERIA

5.0.6 Air Leakage Control

5.0.6.1 Overall Air Leakage -- The natural (not mechanically forced)

leakage of air between indoors and outdoors shall not exceed 0.7 air

change per hour for one- and two- family dwellings and 0.5 air change

per hour for all other buildings and mobile homes.

Compliance with the overall air leakage requirement shall be determined

by calculations from certified data furnished by the manufacturer or supplier on doors, windows, and exterior walls, and supplemented by calculations using the crack method given in the ASHRAE Handbook of Fundamentals,

at the appropriate prevailing design wind conditions for the area of

application. The 0.5 air change-per-hour criterion for all buildings

other than one- and two-family dwellings and mobile homes contains an allowance for chimney effect in tall buildings.

5,0.6.2 Windows and Storm Windows -- Windows shall be designed to limit

air leakage into or from the building. The air infiltration rate of

aluminum, steel, and wood windows shall not exceed the rates specified in

the following applicable national and ^ndustry standards, when tested at

a pressure differential of 1.567 lb/ft , equivalent to the impact pressure

of a 25 mph wind.

22
ANSI A134. 1-1972 Specifications for Aluminum Prime Windows

ANSI A134. 3-1972 Specifications for Aluminum Combination

Vertically-sliding or Horizontally-operating

Storm Windows for External Application.

AAMA 303.2-Jan. 1973 Specifications for Aluminum Mobile Home

Windows (proposed ANSI 134.5)

Steel Window Institute Recommended Specifications for Steel

Windows - 1973

NAAMM Standard SW-1-71 Specifications for Metal Windows

nmA Industry Standard for Wood Window Units I.S. 2-73

Compliance with the criteria for air leakage of all types of windows shall

be determined by ASTM E283-73, Standard Method of Test for Rate of Air

Leakage Through Exterior Windows, Curtain Walls, and Doors.

5.0.6.3 Doors -- All exterior doors shall be designed to limit air leakage

into or from the building when in the closed position.

The air infiltration rates of aluminum and wood sliding glass doors shall

not exceed the rates specified in the following national and industry

standards, when tested at a pressure differential of 1.567 lb/ft .

ANSI A134. 2-1972 Specifications for Aluminum Sliding Glass Doors.

NW4A I.S. 3-70 Industry Standard for Wood Sliding Patio Doors.

The air infiltration rate of swinging doors shall not exceed 1 cfm per

foot of crack in the closed position, when tested at a pressure differential of 1.567 lb/ft .

Compliance with the criteria for air leakage of all types of doors shall

be determined by ASTM 283.73, Standard Method of Test for Rate of Air

Leakage through Exterior Windows, Curtain Walls, and Doors.

5.0.6.4 Exterior Walls -- Panelized exterior walls shall be designed to

limit air leakage at all joints between adjacent panels and at the joints

between panels and other building elements.

Tlie air infiltration ^ate of2the exterior walls, excluding window elements,

shall not exceed 3 ft-/hr ft of area, when tested at a pressure differential of 1.567 lb/ft .

Compliance with the criteria for air leakage of all types of exterior walls

shall be determined by ASTM E238-73, Standard Method of Test for Rate of

Air Leakage through Exterior Windows, Curtain Walls, and Doors.

5,0.6.5 Caulking and Sealants Caulking, sealants, or gasketing meeting

the requirements of the specifications cited in the following paragraphs

shall be used at the joints around all window and door frames, at the

joints between walls and foundations, at the joints between walls and roof,

around the frames of all other openings in the exterior envelope, and at

the penetration of utility services through walls, floor, and ceiling.
The properties of the sealants, caulking, and gaskets must meet the

requirements of the following ASIM and Federal Government Specifications,

as applicable, when tested as specified therein:

FS-TT-S-00227E (Com-NBS) Nov. 4, 1969

Interim Fed. Spec. "Sealing Compound: Elastomeric Type,

Multi-Component (For Caulking, Sealing, and Glazing in

Buildings and Other Structures)."

FS-S-00230C (Com-NBS) Feb. 2, 1970

Interim Fed. Spec. "Sealing Compound: Elastomeric Type,

Single Component (For Caulking, Sealing, and Glazing in

Buildings and Other Structures)."

FS-TT-C-00598C (Com-NBS) June 23, 1970^^

Interim Fed. Spec. "Caulking Compound, Oil and Resin Base

Type (For Building Construction)."

FS-TT-S-001657 (Com-NBS) Oct. 8, 1970

Interim Fed. Spec. "Sealing Compound: Single Component,

Butyl Rubber Based, Solvent Release Type For Buildings and

Other Types of Construction)."

FS-TT-001543A (Com-NBS) June 9, 1971

Interim Fed. Spec. "Sealing Compound: Silicone Rubber Base

(For Caulking, Sealing, and Glazing in Buildings and Other

Structures) ." kSm C509-70

"Standard Specification for Cellular Elastomeric Preformed Gasket

and Sealing Material,"

ASTM C542-71a

"Standard Specification for Lock-Strip Gaskets."

ASIM C570-72-^ "Oil and Resin-Base Caulking Compound for Building Construction."

- Same as ASTM C570-72

2/ - Same as FS-TT-C00598C (Com-NBS) June 23, 1970

24
EVALUATION

Engineering examination and evaluation and test results data.

Evaluation against materials and assemblies specifications as published

by the Federal Government and the American Society for Testing and

Materials. The crack method as given in the 1972 ASHRAE Handbook

of Fundamentals shall be used as the basis for engineering evaluation.

COMMENTARY

The air leakage into and out of a building in winter is a significant

portion of the energy requirement necessary to maintain indoor temperature. The process creating natural air leakage consists of the buoyancy or chimney pressure difference of the dense cold outdoor air and

the lighter warmer indoor air plus the effect of wind velocity pressure

on the building. The air leakage limitation specified is based on what is attainable in construction practice including allowance for

exhaust fan openings fitted with self-closing devices when the fan is

not in use. This criteria is not intended to cover purposely designed

forced ventilation systems in buildings.

Weatherstripping and caulking are required to minimize the loss of

heat energy from air infiltration and to protect the exterior envelope from the elements.

CRITERIA

5,0.7 Condensation Control - Heating -- The design of the building

envelope shall provide protection against cold weather water-vapor

condensation on or in roofs, attics, walls, windows, doors, and floors.

For opaque areas of ceilings, roofs, floors, and walls containing dry

thermal insulation, a continuous vapor barrier 2having a water vapor

permeance not exceeding 0.5 perm (grains/hr ft (in.-Hg)) is required

on the winter-time warm side of the insulation.

Slab-on-grade floors shall have a vapor barrier with lapped joints under

the slab not exceeding 0.1 perm.

A vapor barrier not exceeding 0.1 perm shall be required to cover the

ground area of a crawl space beneath floors.

Ceiling, roof, floor, and wall constructions shall contain thermal breaks

to prevent excessive heat transmission through framing members.

EVALUATION

Engineering examination and evaluation of the design and design

calculations. ASTM Recommended Practice E 241-68 for general design

information, ASIM Test Methods E 96-66 (Procedures A - dry cup) for

materials such as paper, plastic films and other sheet materials that are less than 1/8 inch thick, and C355-64 (dessicant method) for

25
materials greater than 1/8 inch thick such as fiberboards, gypsum

and plaster products on wood products, shall be used to evaluate

vapor barriers, when applicable. A simulated service test or comparison with systems known to be effective shall be used to

evaluate complete wall, floor, ceiling or roof systems.

COMMENTARY

The purpose of these criteria is to prevent indoor water vapor from

condensing on cool surfaces whose temperatures are below the dewpoint temperature of the indoor air and to prevent condensation

within the construction of indoor water vapor that permeates through

indoor surfaces

.

CRITERIA

5.0,8 Orientation and Shape Analysis - Heating -- The proposed design

shall show that energy conservation was among the considerations taken

into account in determining building orientation and shape. The design

submittal shall show that the following factors have been considered in

the orientation analysis: (a) compass orientation of the building on

the site; (b) aspect ratio (ratio of length to width); and (c) the number

of stories for a given floor area requirement.

EVALUATION:

Engineering evaluation of heat loss and energy calculations.

, . COMMENTARY

The intent of these criteria is to require analysis of the options

available to the designer and owner of the building to conserve

energy by taking into account prevalent solar and wind conditions.

For example, if the predominant cold winds come from the north,

the north wall of the building can be designed to reduce the heat

flux, while the east, south, and west facades can be positioned to

take advantage of winter solar heat and designed for minimum solar

heat gain through windows in summer. The length-to-width ratio

and the number of stories for a given building can sometimes be

used as flexible design parameters. Subject to site constraints and

user needs, the shape of the building that defines the amount of

facade area can be varied and the energy consumption examined to

select a minimum and yet allow the functional requirements of the

building to be satisfied.

26
CRITERIA

5.0.9 Alternative Building Envelope Heat Transmission Design Criteria - Heating -- Alternate designs and methods of construction that show total

building heat loss at design conditions to be equal to or less than designs

developed to satisfy all of the above criteria shall be acceptable if submitted as certified by a registered engineer or architect. For the purpose of computing the total building heat loss of the building used as a basis for comparison, the heat transmitted through the ceiling/roof shall

be based on the assumption of 100 percent opaque ceiling/roof area (not

containing skylights or saw-tooth shaped roofs containing windows). The

design heat loss calculation for any alternative building envelope or subelement construction proposed under this criterion shall be determined

for the same indoor and outdoor design temperatures, common occupancy and

use schedules, and equivalent useful floor area, perimeter, and building

volume as for the design complying with all of the preceding criteria in

this Chapter,

EVALUATION

Engineering evaluation of heat loss and energy consumption calculations .

COMMENTARY

The intent of these criteria is to allow a separate performance

approach where maximum flexibility and innovation can be used that

would result in overall conservation of energy from a process of

trading off savings in one area of the building against losses that

exceed the above criteria in other areas of the building. When

this approach is used it is usually done with the aid of a computer

where many options or changes can be examined rapidly and simultaneously for the building as a whole.

CRITERIA (COOLING)

5,0.10 Opaque Ceilings/Roof and Wall - Cooling -- The heat flow through

opaque surface areas of roof/ceilings or2walls facing cooled

interiors shall not exceed 2,0 Btu/hr/ft of ceiling or wall area when

calculated at an indoor design temperature of 78 "F and an outdoor sol-air

temperature calculated as follows:

a ,''dTv eAR

o o where

a = absorptance of the surface for solar radiation

h^ = coefficient of heat transfer2by radiation and convection of

the outer surface, Btu/hr ft "F

1/ Reference equation 42 of Chapter 22, ASHRAE Handbook of Fundamentals,

1972, 27
t = average sol-air temperature, *F ea

t = average summer design outdoor temperature, "F oa

t = t - At/2, where t is the summer design dry-bulb temperature

°^ listed in Table 1, page 669, 1972 ASHRAE Fundamentals Volume, Column 6 2 1/2%, At is the value

given in Column 7, Outdoor Daily Range.

e = hemispherical emittance of the surface.

The average equivalent temperature difference, t

t = t - t,

e ea 1

S , IS

(5)

where t. is the indoor design temperature, 78 "F.

The minimum thermal resistance, R, of the opaque ceiling/roof or wall

Inclusion of the effect of the mass (weight) of the roof or wall in

addition to the above procedures shall be allowed in meeting the heat

flow criteria.

R = the difference between the longwave radiation incident on the

surface from the sky and surroundings, and the radiation

2 emitted by a blackbody at outdoor air temperature Btu/hr ft .

cv/h = 0cl5 for light colored surfaces

° 0,30 for dark colored surfaces

1^^ = 1.15 times the maximum sum of the two half -day totals of

solar heat gain factors for each wall as given in Tables 2 to j pages 388-392, 1972 ASHRAE Handbook of Fundamentals, Btu/hr ft'

eAR/h = 7 "F for horizontal surfaces

= 0 °F for vertical surfaces.

EVALUATION

Examination and evaluation of engineering calculations.

COMMENTARY

The average equivalent temperature difference, t^ , is used in the

criterion instead of actual indoor air to outdoor air temperature

differential to account for solar heating of outdoor surfaces to

temperatures greater than the outdoor air temperature. The examples

in Appendix 1 at the end of Chapter 5 will serve to illustrate the

procedure for limiting the heat flux and determining the required

overall thermal resistance and thermal transmittance (U-value).

28
CRITERIA

5.0.11 Window Heat Gain - Cooling -- The heat gain through transparent

window areas of the exterior envelope shall be controlled during the

cooling season in relation to the geographic location and the compass

orientation of the building on its site. Plain glass without a shading

device is not permitted (e.g., shades, Venetian blinds, draperies,

awnings, eyebrow reveals, or vertical/horizontal fins must be used). The

windows shall be equipped with shading devices, interior or exterior,

that will limit, during the cooling season, the maximum instantaneous

combined sol^r and air-to-air heat transmission at design conditions to

70 Btu/hr ft of transparent window area, as an average for the entire

window

EVALUATION

Engineering examination and evaluation of calculations. For evaluation of design, calculation procedures given on pages 386 through

410 of the 1972 ASHRAE Handbook of Fundamentals shall be used.

CRITERIA

5.0.12 Doors - Cooling — Heating criteria apply (see 5.0.4. and 5.0.6.3).

EVALUATION

See Heating Evaluation, 5,0,4.

COMMENTARY

See Heating Commentary, 5,0,4,

CRITERIA

5,0,13 Floors, Foundation Walls, and Slabs-on-Grade - Cooling -- Heating criteria apply (see 5.0,5).

EVALUATION

See Heating Evaluation, 5.0.5.

COMMENTARY

See Heating Commentary, 5.0,5.

29
CRITERIA

5.0.14 Air Leakage Control - Cooling Heating criteria apply except

that the natural (not forced) leakage of air from cooled spaces to the

outdoors shall not exceed 0.5 volume air change per hour at design conditions for one- and two-family dwellings. (See 5.0.6.1)

EVALUATION

See Heating Evaluation following 5.0.6.5

, ; COMMENTARY

See Heating Commentary following 5.0.6.5

CRITERIA

5.0.15 Orientation on Site - Cooling -- The proposed design shall show

that energy conservation was among the considerations taken into account

in determining building orientation and shape. The design submittal shall

show that the following factors have been considered in the orientation analysis: (a) compass orientation of the building on the site; (b) aspect ratio

(ratio of length to width); and (c) the number of stories for a given floor area requirement.

EVALUATION

See Heating Evaluation, 5.0.8

COMMENTARY

See Heating Commentary, 5.0,8

CRITERIA

5.0.16 Alternative Building Envelope Heat Transmission - Cooling -- Alternative designs and methods of construction that show design total

building heat gains equal to or less than designs developed to satisfy

all of the above criteria shall be acceptable if submitted as certified

by a registered engineer or architect. The purpose of these criteria is

to allow energy trade-offs that would result in equivalent overall con- servation of energy, even though the criteria for selected subelements

of the building may not precisely meet the specified requirements. For

the purpose of computing the total heat gain of the basic building used

for comparison, the heat gain through the ceiling/rood shall be based on

the assumption of 100-percent opaque ceiling/roof area (not containing

skylights or saw-tooth shaped roofs containing windows).

The design cooling load calculation for any alternative building envelope

or subelement construction proposed under this criterion shall be determined for the same indoor and outdoor design temperatures, common occu- pancy and use schedules, and equivalent useful floor area, perimeter, and

30
building volume as for the design complying with all of the preceding

criteria in this Chapter that are applicable to cooling.

EVALUATION

See Heating Evaluation, 5.0.9.

CQylMENTARY

See Heating Commentary, 5.0.9.

31
APPENDIX 1

EXAMPLES ILLUSTRATING THE APPLICATION

OF CHAPTER 5 CRITERIA

5,0,3 Opaque Ceilinp^s/Roof - Heating

1) Location , Duluth, Minnesota

Heating Degree-Days , 10,000 (from p. ASHRAE 1973 Systems Vol)

Required q/A , 3.8 Btu/hr, ft of ceiling area from Criteria 5.0,3.

Design Temperatures

Indoor ,70 °F (from Criteria 5.0.2)

Outdoor, -15 °F (from Tp,67k ASHRAE 1972 Fmdamentals Volume)

Design Temperature Difference , [70 - (-15)] = 85°F

Overall Thermal Resistance , R

„ _ Design Temperature Difference _ 85

q/A " 3.8 " ^^'^^ Overall Thermal Transmittance , (U-value)

U = I

= = 0.0447 Btu/hr ft^ ''F

2) Location - Scranton/Wilkes-Barre , Pennsylvania

Heating Degree-Days - 625^

Required q/A - 3.52

Design Temperature Difference - [70 - 6] = 6k

Overall Thermal Resistance - = is 18 3.52 • °

Overall Thermal Transmittance — = n 05 5 18.18 ^-^^^

3) Location - Atlanta, Georgia

Heating Degree-Days - 296I

Required q/A - 3.5

Design Temperature Difference - [70 - 23] = ^7

47 Overall Thermal Resistance - -^-^ = 13.43

Overall Thermal Transmittance '— - ., } = 0.074 13.43

k) Location - San Diego, California

Heating Degree-Days - 1^+58

Required q/A - 3.59

32
Design Temperature Difference - [TO - hh] = 26

2 6 Overall Thermal Resistance - = 7.24

Overall Thermal Transmittance -

^ = 0.14

5) Location - Key West, Florida

Heating Degree-Days - 108

Required q/A - h,l

Design Temperature Difference - [70 - 58] = 12

12 Overall Thermal Resistance - ;

- = 2.93 4 .

1

Overall Thermal Transmittance - ^ = 0.34

33
5»0,h Gross Exterior Walls (including Opaque Walls, Windov, and Door

Areas) Heating — Table 5.2

l) Duluthj Minnesota , 10,000 heating degree-days

Single-Family

U = 0,066 from Opaque wall criteria wall

, . Assume 10^ single glass and h% metal storm doors

. U X 1 = O.O60 X 0.86 + 1.13 X 0.1 + 0.33 X 0,0k

" ° = 0.057 + 0.113 + 0.013

•

. = 0.183 will not meet 0.17 Criteria

Assume 10^ storm windows and k% metal storm doors

U X 1 = 0.066 X 0.86 + 0.56 X 0.1 + 0.33 X O.Oii o = 0.057 + 0.056 X 0.013

= 0.126 will meet 0.17 Criteri a

Assume U = 0.11 10^ stom windows and k% metal storm doors wall

U X 1 = 0.11 X 0.86 + 0.56 X 0.1 + 0.33 X 0.0k

° = 0.095 + 0.056 + 0.013

= 0.l6^* will meet 0.17 Criteria

Assume 15^ storm windows and h% metal stonn doors

U X 1 = 0.066 X 0.81 + 0.56 X 0.15 + 0.33 X 0,0h

° = 0.053 + O.O8U + 0.013

= 0.15 >fill meet 0.17 Criteria

Assume 20% storm windows and k% metal storm doors

U X 1 = 0.066 X 0.76 + 0.56 X 0.2 + 0.33 X O.OU

° = 0.05 + 0.112 + 0.013

= 0.175 "Will not meet 0.17 Criteria

All other buildings

Assume 10^ insulating glass area and 1% insulated steel door

U X 1 = 0.066 X 0.89 + 0.65 X 0,1 + 0.59 X 0.01

= 0.059 + 0.065 + 0.006

= 0.13 will meet 0.27 Criteria

Assimie 30^ insulating glass area and 1% insulated steel door

U X 1 = 0.066 X 0.69 + 0.65 X 0.3 + 0.59 X 0.01

= O.OI+6 + 0.195 + 0.006

= 0.2kl will meet 0.27 Criteri a

34
Assime 30% single glass area and 1% insulated steel door

U X 1 = 0.066 X 0.69 + 1.13 X 0,3 + 0.59 X 0.01

= 0,0k6 + 0.339 + 0.006

= 0.39 "will not meet 0.27 Criteria

Assime U^g^^ ~ 0,l6, 10% single glass and 1% insulated steel door

U X 1 = 0.16 X 0.89 + 1.13 X 0.1 + 0.59 X 0.01

° = 0.li^2 + 0,113 + 0.006

= 0.261 vill meet 0.27 Criteria

Assume 50^ insulating glass emissivity coating =0.2 and 1%

insulated steel door

U X 1 = 0.066 X O.I19 + 0.38 X 0.5 + 0.59 X 0.01

° = 0.032 + 0.19 + 0.006

= 0.23 meets 0.27 Criteria

2) Scranton/Wilkes-Barre , Pennsylvania, 625^ heating degree-days

^wal"" ~ ^'^'^^ from opaque vail criteria

Single-Family

Assume 5^ single-glass, 10^ storm vindovs and k% metal storm

door

U X 1 = 0.072 X 0.81 + 1.13 X 0.05 + 0.56 X 0.1 + 0.33 X O.Qli ° = 0.058 + 0.057 + 0.056 + 0.013

= 0.184 meets 0.20 Criteria

Assme U = 0.12, 15^ storm windows and h% metal storm doors wall

U X 1 = 0.12 X 0.81 + 0.56 X 0,15 + 0.33 X O.Oii ° = 0.097 + 0.08i; + 0.013

= 0.19^+ vill meet 0.20 Criteria

All other tiuildings

Assume 30^ insulating glass area and 1%> insulated door area

U X 1 = 0.072 X 0.69 + 0.65 X 0.3 + 0.59 X 0.01

= 0.050 + 0,195 + 0.006

= 0.251 meets 0.30 Criteria

Assume 50^ insiilating glass area emissivity coating, 0.6, and 1%)

ins\ilating steel doors

U X 1 = 0.072 X 0.1+9 + 0.52 X 0.5 + 0.59 X 0.01

° = 0.035 + 0.26 + 0.006

=0.30 meets 0.30 Criteria

35
Assmne U =0,20, 10% single glass and 1% insulating steel

, "wall

doors

U X 1 = 0.20 X 0,89 + 1.13 X 0.1 + 0,59 x 0,01

^ = 0.1T8 + 0,113 + 0,006

= 0.29T meets 0,30 Criteria

3) Atlanta, Georgia, 296I heating degree-days

^vall

~ ^'^^^ from opaque wall criteria

' Single-Family

Assme 15^ single glass and k% metal storm doors

: U X 1 - 0.091 X 0.81 + 1,13 x 0,15 + 0.33 x 0,0k

° = 0,07^^ + 0,17 + 0,013

:.?/:= 0.257 meets 0,27 Criteria

All other buildings

Assume 25^ single glass and 1% insulated door area

VU X 1 = 0,091 X 0.7^+ + 1.13 X 0.25 + 0,59 X 0,01

A^., ° = 0.067 + 0.283 + 0,006

= 0.356 meets 0.36 Criteria

v.- Assimie U = 0.27> 10% single glass and 1% insulated door vail

area

U X 1 = 0.27 X 0.89 + 1.13 X 0.1 + 0.59 X 0.01

^. . ° = 0,2h + 0.113 + 0.006

-^-r; -. :, = 0.359 meets O.36 Criteria

Assume insulating glass and 1% insulated door area

U X 1 = 0.091 X 0,5k + 0.65 X 0,k5 + 0.59 X 0.01

= O.0U9 + 0.293 + 0.006

•V ": = 0.348 meets 0.36 Criteria

k) San Diego, California, 1U58 heating degree-days

^vall ~ ^'l"^ from opaque vail criteria

Single-Family

Assume 15^ single glass and k% vood doors

U X 1 = 0.17 X 0.81 + 1.13 X 0.15 + 0.i;9 X 0,0k

= 0.137 + 0.169 + 0.02

=0.32 meets 0.32 Criteria

36
All other buildings

Assiime 20% single glass, 1% insulated door area

U X 1 = 0.17 X 0.79 + 1.13 X 0.2 + 0.59 x 0.01

= 0.13^ + 0.226 + 0.006

= 0,37 meets 0.38 Criteria

Assume kO% insulating glass and 1% insulated door area

U X 1 = 0.17 X 0.59 + 0.65 X 0.I4 + 0.59 x 0.01

° = 0.10 + 0.26 + 0.006

= 0.37 meets 0.38 Criteria

5) Key West, Florida, IO8 heating degree-days

^wall

~ O'^l from opaque wall criteria

Single-Family

Assume 25^ single glass and h% wood doors

U X 1 = 0,hl X 0.71 + 1.13 X 0.25 + O.J+9 X O.OU

° = 0.29 + 0.283 + 0.02

= 0.59 meets 0,60 Criteria

All other buildings

Assume 30^ single glass sind 1% insulated door area

U X 1 = O.l^l X 0.69 + 1.13 X 0.3 + 0.59 x 0.01

= 0.283 + 0.339 + 0.006

= 0.628 meets 0.63 Criteria

Assxime 50^ insulating glass and 1% insulated door area

U X 1 = 0,kl X 0.i^9 + 0.65 X 0.5 + 0.59 X 0.01

° = 0.20 + 0.325 + 0.006

= 0.53 meets O.63 Criteria

37
5.0.4 Opaque Walls - Heating, Table 5.3

(1) Location - Duluth, Minnesota

Heating Deeree-Davs - 10,000 (from p. 43.5 ASHRAE 1973 Systems

Volume)

2

Required a/A - 5.6 Btu/hr. ft of wall area from Criteria 5.2.2

Design Temperatures

Indoor, 70 °F (from Criteria 5.1.2)

Outdoor, -15 (from p. 674 ASHRAE 1972 Fundamentals

Volume)

Design Temperature Difference - [ 70 - (-15) ] = 85 **F

Overall Thermal Resistance , R

_ Design Temperature Difference _ 85 _ t c i q q/A 5.6

Overall Thermal Transmittance , (U-value)

(2) Location - Scranton/Wilkes-Barre , Pennsylvania

Heating Degree -Days - 6254

Required q/A - 4.58

Design Temperature Difference - [ 70 - 6 ] = 64

64

Overall Thermal Resistance - -.—— = 13.97

Overall Thermal Transmittance - .. q^q -? ~ 0.072

(3) Location - Atlanta, Georgia

Heating Degree-Days - 2961

Required q/A - 4.3

Design Temperature Difference - [ 70 - 23 ] = 47

47 Overall Thermal Resistance - —- = 10.93 4.3

Overall Thermal Transmittance - Yo~93

~ 0*091

38
(4) Location - San Diego, California

Heating Degree-Days - 1458

Required q/A - 4.41

Design Temperature Difference - [ 70 - 44 ] = 26

2 6

Overall Thermal Resistance - —7-7 =5.9 4.41

Overall Thermal Transmittance - —-r = 0.17

5 . y

(5) Location - Key West, Florida

Heating Degree-Days - 108

Required q/A - 4.95

Design Temperature Difference -[ 70 - 58 ] = 12

12

Overall Thermal Resistance - 7

— = 2.42 4.95

Overall Thermal Transmittance - -

= 0.41

2 .42

39
5.0.4 Opaque Ceilings /Roof and Wall - Cooling

1) Key West, Florida

From Table 1, p. 671, 1972 ASHRAE Handbook of Fundamentals

Latitude = 24* 3"

Design dry-bulb temperature ,At^ = 89 °F

Outdoor daily range, At = 9 "F

From Table 2, p. 388, 1972 ASHRAE Handbook of Fundamentals

Horizontal Roofs, the maximum half -day total value occurs on June 21, and is equal to 1095

For walls, maximum half -day totals are:

North, 282 a.m. and 282 p.m. on June 21

East, 936 a.m. and 176 p.m. on June 21

South, 451 a.m. and 451 p.m. on September 21

West, 176 a.m. and 936 p.m. on June 21

ea oa h 24 h

o o

For Roofs

9

light colored, t^^ = (89- -) + 0.15

t = 93.2 °F ea

Ate = t ^ - t

t ea 1 = 93.2 - 78

= 15.2

15 2

U = 0.]3

1.15 (1095 + 1095)1 -. 24 J

40
Hark colored^

9, , n

„ r i.l5 (1095 + 1095)1 . =

^ ea 1 = 109 - 78 = 31

R =-1-^. 15.5

At

q/A 2.0

U = 0.065

For walls

]ighf- cn^nrpA

North, t = (89 - 7) + 0.15 ea z 1.15 (282 + 282) 1

24 J

Atw = t - t. ^ ea 1 = 88.6 - 78

= 10.6

R = iO^= 5 3 ^ q/A 2.0 ^--^

U = 0.19

East, t - (89-f) +0.15r i-lS («6 + "6) ] ea 2 _ 24

Att = t - t. ea 1 = 92.5 - 78

= 14.5

^ q/A 2.0 ^-^^

U = 0.14

c . - / 9. . ^ I 1.15 (451 + 451) South, t^^ - (89-2^ + 0.15

I ^24

Atv = t - t, ea 1

=90-78

= 12

^\ 12

U = 0.17

41
^^ u. n -.c ^ 1.15 (176 + 936)

" West, t^^ = (89 - + 0-15 _ 24 .

AtL = t - t.

^ ea 1 = 92.4 - 78 = 14.4

14 4 ^ q/A 2.0

U = O.J 4

dark colored

North, t^^ = (89 - f)

+ 0.30 [

1-13 (282 + 282) -j

At^ = 92.7 - 78 = ]4.7

- 14.7 ^ " q/A 2.0

''•^^

U = 0.34

9. . ^ r 1.15 (936 + 176 )^

East, t = (89 - r) + 0.30 i ea / - 24- -'

Atr = t - t. ^ ea 1 = ICO. 5 - 78

^ =22.5

- = 22 .5 ^

' ' ^

" q/A 2.0 ^^-^^

U = 0.09

9, ^ _ r i.l5 (451 + 451) 1

South, t = (89 - t) + 0.30 |

I ea 2 L Z^ J

Ate = t - t. ea 1 = 9 7.5 - 78

= 19 .5

19.5

U = 0.10

42
West, t^^ = (89 - 2) + 0-30

Ate = t - 78 ^ ea

= 100.3 - 78

= 22.3

r i.15 (176 + 936)

L 24

- 0 = 100.3

R = _ 2 2.3

q/A 2.0

= 11.15

U = 0. 09

(2) San Diego, California

Latitude = 32 ° 4' Design dry-bulb temperature, t = 83 °F

Outdoor daily range, At = 12 °F

Horizontal Roofs, max. half-day total = 1119 on June 21

For walls, max. half-day totals are:

North, 252 a.m. and 252 p.m. on June 21

East , 972 a.m. and 180 p.m. on June 21

South, 8^4 a.m. and 844 p.m. on December 21

West , 172 a.m. and 983 p.m. on May 21

t = t + ^ (^) - ^ ea oa h 24^ h

o o

For Roofs

ZStc = t - t. ea 1 = 86 - 78

= 8 °F

8 ^ = ?7I = 2-^o=^-^

U = 0.25

43
^1 1 A . - r 12.,„„ [ 1.15 (1119 + 1119) 1 , -.no dark colored , t = ( 83 " "T^ ^-^ — o7 ^ ——— : " 7 = 102 °F ——— ga. z ZMAte = t - t.

t ea 1 = 102 - 78

= 24 °F

24

U = 0.08

For walls

light colored

North, t.. = (63 - i|) -H 0.15 [

l-15 (252 + 252) ^ . „ _ ^^^^

ea

Ate = t - t. ea 1 = 8 0.6 - 78

= 2.6

^ q/A 2,0

U = 0. 77

E.st, t^^ = (83- i|) + 0.15 [

1-13 (972 . ISO )-] . „ ^ 33^3

Ate = t - t. ea 1 = 85.3 - 78

= 7.3 °F

7 3

U = 0.27

44
South, t = (8 3 - ^) + 0.15

ea 2

1.15 (844 + 844) 1 ^ 24 J

° = 89.1 °F

^ ea 1 = 89.1 - 78

= 11.1

R =

_ 11.1 _ q/A 2.0

U = 0.18

5. 55

TT ^ ^ - /Qc, 12^ + n 1^ ri-15 (983 + 172) 1

ea

ea

At

t. = 85.3 - 78 = 7.3

1

0 = 85.3 °F

U = 0.2 7

dark colored

North, t = (83 - % + 0.30 \

Ld^-Jl^L±J^l . q = 90.2 °f ea 2 L 24 -1

= tea

- = 90.2 - 78

= 12.2

12 .2

U = 0.16

East, t = (83- f) + 0.30 L^^i^^H^-^^'- 0= 93.6 °F

At ^ = t . - t.. ea 1 = 93.6 - 78 = 15 .6

^ q/A 2.0

U = 0.13

45
/oQ 12. . ^ ! 1.15 ( 844 + 844) South, t = (83 r) + 0.30 -Vj ^

' ea 2 I- 24

Ate = t - t. = 101.2 - 78 = 23 .2

^ ea 1 ^\ 23 2

R = -77 = 7^ = 11.6

q/A 2.0

U = 0.09

west, t = (83 -^)^ 0.30 r ^-" (^83^172) ].

ea 2 '-24 -i

Ate = t - t. = 93.6 - 78 = 15.6

^ ea 1

: ^ q/A 2.0

U = 0 . 13

46
APPENDIX 2

HEAT FLUX, THERMAL RESISTANCE, AND THERMAL

TRANSMITTANCE VALUES-^ FOR CEILINGS, ROOFS,

AND OPAQUE WALLS MEETING THE DESIGN

CRITERIA OF TABLES 5.1 AND 5.3 FOR

243 U. S. CITIES

11 The degree-day and winter outside design temperature

in this Appendix are taken from ASHRAE Systems Volume

(1973) and the ASHRAE Fundamentals Volume (1972),

respective ly

47
APPENDIX 2 STATE STATION

AL « . B 1 R" I NGHAM

HUNTSVILLE

"CP I LE r-ONTC-OMERY

A L / S K A anchcrage

FA I 4NKS

JUNEAU

NC^<F ARIZ. FLAGSTAFF

PhOE M I X TUCSON

W I N S L 0 * YUKA

APl^ , FORT SMITH

LITTLE ROCK

TEXA^KANA

CAI IF. OAKFPSFIELO

9UKBANK

EUPF K A FPE?^'C

L 0 ^.. G P E A C H LOS AMGELES

0 a K L A 0

S A C F A H E N T 0

S A K r I E G 0 s^^; FRANCISCO

SA^!T^ MARIA

CGI 0 . COLORADO SPRINGS

DF ^;Vf P GFAf.^r JUNCTION

P L. F f L 0 BPirr-EPOPT

HARTFORD

^'tl' l-'AVEN' ntL . If.- I L ^ I r- G T C N

D . r . * A 5 t-' I N 6 T 0 N FLA. DAYTCNA REACH

FORT "YEf^S

J A r K r 0 N V I L L E

K F Y '/ F S T L A K F L A N P ' - " M I A f" MIAMI BEACH

0 F L A P 0 PENS A COLA

T A L I r-' H A S r E E

T A " P A WEST PALM BEACH

GA . AT HFr'S ATLA MTA

OEGREir TES I GN OF S I GN CF 1 OA Y Tt MP . AT 0 /A

2S5 1 22 48 3.50

3n7C 1 7 53 3.50

1 560 29 4 1 3.59

229 1 26 4 4 3.5-^

1 GP6M -20 90 3.89

1 4279 -50 1 20 4.40

9 0 7 5 -4 74 3.71

14 17 1 -28 98 4 . 4G

7 152 5 65 3.60

1 765 34 36 3.55

1 90C 32 38 3.54

1782 1 3 57 3.50

9 7 "4 40 30 3.71

3292 \ 9 5 1 3.50

32 19 23 47 3.50

2533 26 44 3.50

2 122 3 3 3 7 3.=.0

1 6M6 38 32 3.57

4643 35 35 3.50

26 11 3 1 3 9

1 803 38 32 3.54

7C6 1 43 27 3,50

2P 7C 37 33 3.50

2502 32 38 3,50

1 458 44 26 3,61

30 1 5 37 33 3,50

2<'67 34 36 3.50

6423 4 66 3.54

6 283 3 67 3.53

564 1 1 1 59 3 .50

5462 - 1 7 1 3 . "^0 56 17 8 62 3 . e^O 6235 5 65 3.52

5897 9 6 1 3.5 0 493C 1 5 55 3,50

4224 1 9 5 1 3.50

P79 36 3 4 3.76

442 42 28 3.08

1239 32 3P 3.65

1 DP 58 1 2 4.15

66 1 39 3 1 3.87

2 1 4 47 23 4.09

! 4 1 48 22 4.13

766 37 33 3 . P 2 1463 32 3 8 3.61

1 485 29 4 1 3.60

683 39 3 1 3.86

25 3 a 4 26 4.07

2929 2 1 49 3 . 0 296 1 23 47 3 . CO

48

LIMG/ROOF WALL

R U Q/A R U 13.71 .07 4 .30 11.16 .09

15.14 .07 4 .30 12.33 ,08

11.43 . 0 9 4 .39 9.34 . 1 1 12.57 .08 4 ,30 10.23 . 10 23.16 .04 5 ,73 15.71 .06

27,27 .04 6 ,00 20.00 .05

19.96 .05 5 .32 13.90 .07

22.27 .04 6 .00 16.33 ,06

18.16 ,06 4 .83 13.46 ,07

10.15 . 10 4 .35 8.28 . 1 2 10.73 .09 4 , 3

'< 8.76 , 1 1 16.29 .06 4 ,38 13.02 .08

8. OP . 1 2 4 ,61 6.65 . 1 5 14,57 .07 4 .30 11.86 .08

13.43 .07 4 .30 10.93 .09

12.57 .08 4 . 30 10.23 . 1 0 10.57 .09 4 . 30 8,60 . 1 2

8 .96 . 1 1 4 .37 7 .32 . 1 4

1 n . nn .10 4 .36 8.02 . 1 2 11.14 .09 4 .30 9.07 . 1 1 9.04 . 1 1 4 .34 7 .37 , 1 4 7.7! . 1 3 4 .30 6,28 . 1 6 9.43 . 1 1 4 . 30 7.67 . 1 3

1 0 . P6 .09 4 .30 8.84 . 1 1 7.21 . 1 4 4 . 4 1 5.90 . 1 7 9.43 . 1 1 4 . 30 7.67 . 1 3 10.29 . 10 4 .30 8.37 . 12 18.63 .05 4 .63 14.26 .07

1 P . 99 . 05 4 .58 14.61 .07

I 6 . P6 .06 4 .46 1 3.22 ,08

2 0.29 .05 4 .45 15.97 .06

17.71 .06 4 .46 13.90 .07

18.45 .05 4 .57 14.22 .07

17.43 . 06 4 .49 13.59 .07

15.71 .06 4 .39 12.52 .08

1 4 . t7 .07 4 .32 11.80 .08

9.04 . 1 1 4 .56 7.46 . 1 3 7.04 . 1 4 4 .78 5 .86 . 1 7 10.40 . 1 0 4 .45 8.54 . 1 2 2.09 .35 4 .95 2.43 .41

8.01 . 1 2 4 .67 6.64 . 1 5 5.62 . 1 a 4 .89 4.70 . 2 1 5.33 . 1 9 4 .93 4.46 .22

8.65 . 1 2 4 ,62 7.15 . 1 4 10.53 .09 4 , 4 1 8.62 . 1 2 11.38 .09 4 .40 9.31 . 1 1 8.03 . 1 2 4 .66 6 .65 . 1 S 6.38 . 1 6 4 .87 5.33 . I 9

1 4 . on .07 4 .30 1 1 .40 .09

1 3 . 4 .07 4 .30 10.93 .09
STATE S T / T I 0 M DEGrFE DESK

DAY TEMP , AUGUSTA 2397 23

COLL-fBUS 2383 26

M A C C- ^ 2 136 27

ROfir 3 326 ?0

SA Vtf N'AH I fl 1 9 27

HA'-t I I HCUJni ULU n 62

H I LO 0 6 1

I D t H 0 PO I 5t 1 0

L E V= I S T 0 N 5542 I 2 pccatfllo 7r 3 ? -2 ILL. rnir^GO (o»hare) 6639 0 CHICAGO (MIOIA'AY) 6 155 1 CHICAGO 5882 1 M c l I

^• E 6'<oe -3

PEORIA 6025 2 ROCKFORD 6P30 -3

SfR T ^ GF I ELD 5'<29 4 IMP, F V A ^l 5 V I L L E '4435 1 0 FORT A r E 62G5 5 Tf'DIAMAPOLIS 5699 4 SOUTH e E M D 6'* 3° 3

I 0 If' A BURLINGTON 6 1 1 S 0 OES ^CINES 6586 -3

OUpUPUE 7 376 -7 SIOUX CITY 695 1 -6

watfrloo 7 32r -8

0 C ri r. F CITY 4986 7 G 0 0 P L A fJ D 6 1 m 4 TOPFKA 5 18? 6

VV 1 r H ! T A 4 6 20 9 K Y . c 0 V 1 N T 0 r: 5 265 8 LEX I ^' G T 0 N 4683 1 0 LOUI'^VILLF 4660 I 2

L A . ALEX/'rJDRiA 192 1 29

nATrt. ROUGE 1 56*^ 30

LAKF CHARLES 1 "5° 3 3 N t n p L E A M S 1 385 35

5HRFVFP0f?T 2 184 26

Mf ! riE C A R 1 L! C U 9767 - I f °tiPTLANP 75 11 0 RALf !^ORE 465" 1 5 ^FFTf RICK 5087 1 1 MASS. n p 5 T r ^| 5 6 3 4 1 C PiTTFEIELO 757P - 1 ifjOf-CFSTER 6''69 1 MICH. PETPO I

623? 8

F S C ' ' A B A 8 4 8 1 -3 FL I T 7 3 7 7 3 GF'A'n RAPIDS 6P9« 6

L A M *; i G 6"' 0 9 6

GN DESIGN CFILING/ROOF WALL

0 / A p Ij Q / A

11W

H 7 3 • 5 C • u / 4" .• n J u 10.93 .09

H ^ J • u i 7 . 7 n fl ^ • J U in 7 1 1 n

^ 3 t 7 * 7 Q n fl in n n 1 n c c 3 ^ c p

1 il . 7 Q n 7 " • J U

11 A 1 1 1 . 0 J n 0 . u 7

H 3 3 , c *4 1 7 . 1 A n fl 4 1 U Q 0 7 - 1 n

• ?n 1 • ^ 0 • 5 2 -5 . U U 1.60 .63

9 *t • 2 0 7 - 1 44 4 7 5.00 1

1 •

fl0 nu

C, A

J • enJ u 1 7 * 1 U n L U U Q T . T O 11 1

Q

n 7

! A . 7 . u o T . H b 11 n 7 n ft An 7 n n n n c H • 8 I 14 0 fl n 7 7 P *\ C A 1 o . A u . u b

tl A o 14 07 n 7

^ 9 O - <

1 O . A ^ • u b T t b b1 C. 1 fl n 7

f 9 3 , o 1 9 • 7 1 uT . u o T T 1 ^ 17 n 7 7 3 2 n • A 7 • nu tb

U i 7 1 c; 70 n A

6 6 1 0 . M t1 V t ^ I n t • u b 1 • b I

1 c no n 7 7 3 7 n 17 . u b

U "7 C 1 ^ 17 n 7 O O ^ c n 1 Q A A . ij b

u u u t . 1 T 14I 7 »

fl0 A0 n 7 Ao nL' ^ c n 17 1 U . U 6 *t • 3 H 11 01 n 7 68 J •

- c:1) ^9 1 fl . U A "•bo 14 7 -07 t u / o o 7 c n 1 A . fl A 14 7 7 n 7 A 7 J t r»

t fl . 0 1 • u b " . 6 J 14 4 7 n 7 7 0 J • Z> 1 1 9 t 9 *4 . u b " . b J

1 Q 4 4 n A

7 7 n . t 1 f U b1 Q A 1 n A

^ An 7 1 > Q n Q • u b

U D 1 e 7 0 n A

7 A 1 An 7 1 1 u n CL • u b

U "TO T • / T

1 e fl fl n A 7 8 ^ An 7^

11 • An 7/ . U b

UT Q i. . o 6

1 A n 4 n A

A > ^ c n 1 fl n n n i * U 6u" u n • 1 u 14 17 n 7 6 6 J • ~ 1 1 8 t 7 P n ^ 7 • b

" 1 4 . c; 1 . n 7 A ^ 1 fl - 7 0 * n e; • U 3 ~ . 7 ^: 14 4 9 .07

L. 1 O 1 1 c n . U 6 M . 3 6 11 0 fl n 7 A 0 17 7 1 Pi i 14 n 1 n 7 A n 1 7 . ! a il A 4 . 7 1 3 . 7 * . n 7

I 6 • 5 7 « U O 47 . J17/ 11 7 fl • 0 8

M^ 1

1 7 C 7 II A A • nU oV 4 17 Q en . 1 1 • i 1

ii n "i CO 11 1 C I 1 • I b • 0 9 4.39 0 1 7 1 1 • 1 1 > 7 T A 1 in "* c 1 n 4 H 1

fi 10 1 7

^ A 7 O . A A 1 n 4 U 7 7 9 1 - 1 1

q q ^ c n 17 t 7 n Q u in in 7 1 I LP » ^ J 1 n

7 7 7 U • U M t CL 1 b . b J1 e to n 7 7 n J^ •

i. n A U to U U n CL • u b

47 » on7 u 14 7 fl n 7

1 C 7 1 1 b • / I . nu Ao4 1 7 17 AO .06

^ 9 1 A fl A n i

* U 6 4 • M 1 11 1 H n 7 n O I

1 en 1 7 • ! M n L

t U 6 H . A 11 4 4 n 7

1 A P 1 O 7 7 • J b 4 07 14 4 4 n 7 A O J

1 t AAnU

1 O 1 Q p c . u bU "7 0 14I t « 47 nU n 7 . u / A 7 C 7 ! 7 • A n n A 47 .• t 7 D / 11 e 7 • 0 7 7 J • A b

7 n n 1 . U b b . J M 14 1 0 J 7 , 1 7 n 7 A7 3.6r 1 8 . A 1 .05 *f .88 13,74 .07

A 4 3,S9 17.83 .06 M.77 13.42 .07

6*4 3.99 17.87 .06 H.77 13.41 .07

49
5 TA TE rf A 1 I ON 0 E G R F F 0F5 I ( DAY TEMP

MATuFTTE P 3 9 ? _ q N U S K f- G 0 N 6t^9 8 SAUlT STE, MflPlf 9rMB -8

M I . D U L

1

' H I OOCO - 1 5

M I N 11 1 A P 0 L I S P383 - 1 0 ROr^'f ?TER P?95 - 1 3 M I . J A C K 5 0 M 223° ? 4 M f P I 0 I' A M 2289 ?4

VICCSPURG 204 1 26

MO » C 0 L L"^ P I A 504r 6 KArj?A5 CITY 17 1! 8 5T . JOSEPH S 4 B t 3

"^T . LOUIS 4 9 00 8 ST, LOUIS 1 4 B

" 1 1 SPRP'CiFIELO t 9CC 1 C Mr ^lT

.

PILL 1 NGS 7049 -6

^L A S'^0* 8996 - 20

GPf A T FALLS 77SC - 1 6

H A V R f 8 7CC - 1 5 H £ L F r ! A 8 129 - 1 3 K A I ! ^ H F L L 8 19 1 - 3 MILE? CITY 7 7 2 3 - 1 5

I S ? 0 LI L A e I 2 B _ 3 gramp island 6530 _ 2

L I N f 0 L 5864 c ^K R F 0 1 K 6979 _ 7 NORTH PLATTE 6684 -2

n H A H A 66 12 - 1 SCOTISRLUFF 6 6 7 .T _ 1) M f v F 0 A F L K 0 7 4 3 3 - 7 ELY 7733 -2 LAS V F G A S 2 70° 26 REN f 6 3 3? 7 WINT'ifUCCA 6 7 6 1 C 0 fj f P p 0 7 3 8 3 _ -7 N.J. atl'^'-'tic city 4 8 1? 1 0

M E If "' A H! K 4569 1 5

T R F r T 0 M 4 9 80 1 6 N . n , ALPLf U ERODE 4 3 4 8 1 7 PATrv 6 ? 2 8 2

R 0 5 '.' £ L L 3 79 3 1 9 SILVER CITY 370b 1 6

A L B A Y 6875 0

B INr. HAMTON 7286 2 RliFF A LO 7062 6 NEW YORK(CENT,PK.) 487 1 1 5 NEW YORK(LA GUARDIA) 4 8 11 1 6 M F W r P K ( K F N M E n V 1 5 ? 1 9 2 ! ROCt-f STER 6748 5 schfmectady 665f' - 1

DESIGN CEILING /pnOF WALL

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7 1 3.5A 1 9.<?? • 05 4.69 15.12 .07

50
STATE STATION DEGREE OES I DAY TEMP

6756 2 N . C . ASHryiLLE ^ni 2 I 7 CHARLOTTE 3 19 1 22

GRErnSBORO 3fl05 1 7 R A L F I r, H 3393 20

M L'l ' NCTON 23H7 27 'VINSTON-SALEM 3595 ! 7 N.O, P I S'MRK 855 1 - 1 9 OEVtUS LAKE 990 ! -19

FARGO 9226 -17

W 1 L L I 5 T 0 N 92M 3 - 1 7 OH r c UKRO-^-CANTON 6037 6

C I N C I M M A T I 1 2 CLEVELAND 635 I 7 COLUlBUS 566C 7 OAYTTN 5627 6 MANSFIELD 6M03 3 SANO'fSK Y 5796 8 TOLE'^0 6M9M 5 Y0UN5ST0WN 6M 1 7 6 OKL 4 . OKLAHOMA CITY 3725 15 TULSA 3P6C ) 6 0 R fi f- 0 N ASTORIA 5 186 30

"^USFME '4726 26

MEDFORO 5':0C 23

''ENnLFTON 5 127 1 0 PORTLAND '4635 24 i^OSF^URG 14149 I 29

S A L F

-1 M75« 25

P E ^.' M . ALLE'^TO*M 58 1 P 5

F*? I F 6«5 1 1 t MAR'^ISBURG 525 1 1 3 PHILADELPHIA 5 1 1 5

P I TTSPURGH 5987 9 READING •4945 9

S C R A N T 0 ^| 625'^ 6 ^ILLIAMSPORT 59 5 P.I. OROVIOENCE 595H 1 0 S.r

.

ChA.?LESTON 2 "13 3 77

CCl'-'I^B I A 2484 23

FLORENCE 2387 25 GREEMVILLE-SPAf?TEMBUi»G 2930 23 s.o. HURON 9 2 2 3 - 1 2 RAPID CITY 7 3*)5 -6

SICUX FALLS 7P39 -10

T E ^ K' . BRISTOL 4 14 3 1 6 CHATTANOOGA 3 25'-l 1 9

K N 0 X V I L L E 3494 1 7 MEMPHIS 3232 7 1 NASuVlLLE 3578 1 6

GN DESIGN CEILING/ROOF WALL

Ova R U Q/A R U 68 3,58 19.0? .05 4.73 14,39 .07

63 3 .50 15.14 .07 4 . 30 12,31 .08

48 3 .50 13.71 .07 4 . 30 11,16 .09

•^3 3.50 15.14 .07 4 . 30 12,33 .08

5 0 3.50 14.29 .07 4 .30 11.63 .09

43 3.50 12.29 .08 4.30 10,00 . 10 53 3,50 15.14 .07 4 . 30 12.33 .08

09 3.69 24.15 .04 5.26 16.94 .06

P9 3.79 23.48 .04 5.57 15,98 .06

87 3.72 23.37 .04 5 , 37 16,21 .06

87 3.72 23.36 .04 5,37 16,19 ,06

64 3.50 18.27 .05 4.51 14.19 .07

58 3 , 5P 16.57 .06 4.34 13.36 ,07

63 3.54 17.82 .06 4.61 13.68 .07

63 3,50 18.00 .06 4.47 14.11 ,07

64 3.50 18.29 .05 4.46 14.34 ,07

67 3.54 18.9? .05 4 .62 1 4,50 ,07

62 3.50 17.71 .06 4.48 13.84 ,07

65 3.55 18.31 .05 4.65 13,98 ,07

64 3.54 18.07 .06 4.63 13.84 ,07

55 3.50 15.71 .06 4.30 12.79 .08

54 3.50 15.43 . 06 4.30 1 2.56 ,08

40 3 .50 11.43 .09 4.42 9.05 . 1 1 44 3.50 12.57 .08 4.37 10.06 . 10 47 3 .50 13.43 .07 4.40 10.68 .09

60 3.50 17.14 .06 4.41 1 3,60 .07

46 3.50 13.14 .08 4.36 10.54 .09

4 1 3.50 1 1 . 7 t . 09 4.35 9.43 . 1 1 45 3 .50 17.86 .08 4.38 10.28 . 1 0 65 3 .50 1 8 . 57 .05 4.48 14.51 .07

59 3.55 16.64 .06 4.64 12.73 .08

57 3.'^n 16.29 .06 4.43 12.88 ,08

55 3.50 15.71 .06 4.41 12,46 ,08

6 I 3 . 5n 17.43 .06 4.50 13.56 .07

6 1 3.50 17.43 .06 4.39 13.88 .07

64 3.53 18.15 ,06 4 .58 13.99 .07

65 3 .5" 18.57 .OS 4.49 14.47 .07

60 3.50 17.14 .06 4.50 13.35 .07

4 3 3.5r. 12.29 .08 4.30 I n.oo . 1 0

» 7 3.50 13.43 .07 4 .30 10.93 .09

45 3.'^0 1^.86 .08 4 . 30 10.47 . 10 47 3.50 13.43 .07 4 . 30 10,93 .09

82 3.62 22.64 .04 5.07 16.18 .06

76 3.60 2 1.11 .05 4.87 15.61 .06

80 3.60 22.2? .04 4.97 16.10 .06

54 3.50 15.43 .06 4.31 12.52 .Ob

5 1 3 .50 1 4 , =.7 .07 4 . 30 11.86 . Ott 53 3 . =. 0 15.14 .07 4 . 30 12.33 .08

"9 3 .50 14.00 .07 4.30 11.40 .09

5 4 3 .50 15.43 . U6 4 . 30 12.56 .08

51
5 T A T F b T I ION r\ C r a C c

0 r. " R ^- C " t S I < PAY TEMP

TEXAS 4 B I t E N E 262^ 2 1 A H A P I L L 0 39S5 1 2 AUSTIN 17 11 29

BRO'ii^SVILLE 600 40

CORPUS CHRISTI 9 1 H 36

OALL AS 2363 24 PL PASO 2700 25

FORT WORTH 2H05 24 GALVESTON 1 27'( 36

HOUSTON 1396 32

L A F DO 797 36

LURBOCK 3578 t 5 MIDLAND 259 1 23

PORT ARTHUR 1147 33

SAf: ANGELO 2235 75

SA^' ANTONIO 1 5^16 30

VICTORIA 117 3 32

A C 0 2030 26

''M C H I T A FALLS 2832 1 9

U T .£. H SALT LAKE CITY 6052 9 VT . BURLINGTON 8269 -7

VA . LYixjCHBUSG 4 166 1 9

^l 0 R F 0 L K 342 1 23

R 1 C H M 0 rj 0 3865 1 8 ROA'lOKE 4 150 I 8 W A H . 0 L Y M P I A 5236 2 5 SEAT TLE-TAC"^^A 5 145 24 SEATTLE 4 4 ? 4 32

^^POK" A NE 6655 4 '.VALLA * A L L A 4 8G5 1 6

Y A f. I M A 594 1 1 0 CHARLESTON 4476 1 4 ELK T '"S 5675 5 MUijT I NGTON 4446 1 H PATKERSBURG 4754 1 2

1 5 r

.

R r r 9 A Y 8029 -7

LA CROSSE 7589 -8

M A 1.1 1 s n N 7863 -5

f-l I L A U K E E 7635 -2

W Y 0 , CASPER 74 J 0 -5

C H E Y c N N F 736 1 -2

L A'|-FR 7870 -12

SHf, P I D AN 7660 -7

RN DESIGN CEILING/RCQF WALL

flT n/A R U Q/

A

R U 49 3,50 14,00 ,07 4 .30 1 1 .10 ,09

5 8 3 .50 16,57 ,06 4 .30 13,49 .07

4 1 3.56 11.5? ,09 4 .36 9,41 . 1 1 30 3 .90 7.69 , 1 3 4 .70 6.38 .16

34 3.74 9.08 , 1 1 4 .54 7,48 . 1 3 46 3.^n 13.14 ,08 4 .30 10.70 ,09

45 3.50 12.06 ,08 4 .30 1 0.47 .10

46 3.50 13.14 .08 4 . 30 10.70 .09

34 3.65 9,33 , 1 1 4 .45 7.65 . 13 36 3.62 10.47 , 10 4 .42 8.60 .12

34 3.80 8,94 , 1 1 4 .60 7.39 . I 4 55 3.50 15,71 ,06 4 .30 12.79 .06

47 3 .50 13.43 ,07 4 .30 10.93 .09

37 3.61 1 n, 7S , 10 4 , 4 1 8.39 . 12 45 3 . =.0 12.86 .08 4 . 30 1 n,47 . 1 0 40 3.59 11.14 .09 4 . 39 9.11 . 1 1 38 3.67 10.37 . 10 4 .47 8.51 . 1 2

4 4 3,50 12,57 .06 4 .30 10.23 .10

5 1 3.50 14,57 .07 4 . 30 11.86 .03

6 1 3,5 1 17,40 .06 4 .52 13.51 .07

77 3.63 71.23 .05 5 .08 15.16 .07

5 1 3,50 14.57 .07 4 .32 11.81 .08

47 3.50 13.43 ,07 4 . 30 10,93 .09

52 3,50 14.86 ,07 4 . 30 12.09 .06

52 3.50 14.86 .07 4 .31 1 2.05 .08

45 3 ,50 12.86 .06 4 .42 10.17 .10

46 3.5 0 13.14 .08 4 .41 10.42 . 10

3 8 3 .50 10.86 .09 4 .34 8,75 . 1 1 66 3.57 18.51 .05 4 .70 1 t.05 .07

54 3.50 15.43 ,06 4 .38 12.33 .06

60 3.50 17.14 .06 4 .49 13.35 .07

56 3.50 I 6.00 .06 4 .35 12,88 .08

65 3.50 18.57 .05 4 .47 14,55 .07

56 3,50 1 6,00 .06 4 .34 12,89 .08

58 3.50 16,57 .06 4 .38 13.26 .06

77 3.60 21,37 .05 5 .01 15.37 .07

78 3.60 2 1,67 ,05 4 .92 15,86 .06

75 3.60 20 , «3 ,05 4 .97 15.08 .07

72 3.60 20.00 ,05 4 .93 1 M,61 .07

75 3.60 20.83 .05 4 .86 15,36 .07

72 3,60 20.00 .05 4 .86 M.77 .07

"2 3 , 60 22, If .04 4 .97 16,49 .06

77 3 ,60 2 1,39 .05 4 .94 15.60 .06

52
CHAPTER 6

HEATING, VENTILATING, AND COOLING SYSTEM REQUIREMENTS

HEATING AND COOLING LOADS

6.0 REQUIREMENT

Heating and cooling loads shall te determined for the purpose of sizing

heating, ventilating and air conditioning, (HVAC) systems and components

for efficient utilization of energy,

CRITERIA

Note: The following items, 6,0,1 through 6,0,2,6, refer only to

parameters for use in calculating heating/cooling loads . For equipment

and system requirements refer to 6.1 through 6.5.

6.0,1 Procedures — Heating and cooling loads shall be determined in

accordance with procedures described in the American Society of Heating,

Refrigerating, and Air Conditioning Engineers (ASHPiAE) Handbook of Fundamentals, Chapters 21 and 22, or procedures for which similarity to ASHRAE

procedures can be demonstrated.

6,0,2 Design Parameters — The following design parameters shall be used

in the heating and cooling load determination: (if for special cases other design conditions are selected, heating and cooling load calculations

shall be based on the selected conditions.)

6.0.2,1 Outdoor Design Conditions — Winter and siiramer outdoor design

conditions shall be the 97-1/2 and 2-1/2 percent values, respectively,

as given in Chapter 33, Weather Data and Design Conditions, of the ASHRAE

Handbook of Fimdamentals , 19T2,

6,0,2,2 Indoor Design Conditions — Winter indoor design conditions shall

be 70 °F dry-bulb temperature, with hiimidifi cation, if provided, to not

more than 30^ relative humidity. Summer indoor design conditions shall

be 78 °F dry-bulb temperature, with controlled dehumidification, if provided, to not less than 60^ relative humidity,

COMMENTARY

ASHRAE procedures will be used to determine the adequacy of submitted

calc\ilations

,

The winter and summer design temperature levels selected for load

calculations were chosen to discourage oversizing in the selection

of HVAC equipment.

53
CRITEEIA

6.0,2.3 General Ventilation ~ For load design of all building types except one- and tvo-family dwelling imits , mechanical ventilation with outside air, for the purpose of meeting normal respiratory and odor control

needs shall be taken as 5 cfm— per person for certain spaces or two

air changes for other spaces (see 6,0,2,^+ and 6»h,l'^ for description and

criteria)

,

6.0.2.U Special Ventilation — For load design, mechanical ventilation

capacity in excess of 5 cfm per person (or two air changes per hour) for

the purpose of controlling smoking contaminants, toxic gases, or other

contaminants, shall be the actual amount included in the design (see 6,i|.15).

EVALUATION

Examination and evaluation of engineering calculations.

CRITERION

6.0.2.5 Infiltration — For load design, infiltration shall be taken as O.T air change per hour for one- and two-family dwellings and mobile homes,

and 0,5 air change per hour for all other buildings, (see 5.0,6.1)

EVALUATION

See Evaluation for 5.0.6.

CRITERION

6.0.2.6 Heat Gains — Internal heat gains shall be included in both

heating and cooling loads as appropriate.

EVALUATION

Examination and evaluation of engineering calculations.

COM!y[ENTARY

In buildings that have a reasonably steady internal heat release of

appreciable magnitude from sources other than the heating system, a computation of this heat release under design conditions should be made

for deduction from the total of the computed heat losses.

!_/ Wherever the term cfm is used in this document it shall be interpreted as standard cubic feet per minute, unless the immediate

context indicates another meaning.

54
EQUIPMENT EFFICIENCY

6.1 REQUIRENENT

Manufacturers of "building equipment defined as energy- significant equipment shall make available to prospective building owners or their representatives the full-load energy-utilization efficiency of such equipment,

taken by itself.

CEITERIA

6.1.1 Full-load Efficiency — The manufacturer shall make available to

prospective purchasers the full-load energy-utilization efficiency

of the specific models to be furnished based on equipment in new condition.

Furnishing of certified test data is deemed to satisfy the requirements

of this paragraph.

6.1.2 Rounding-Off — For the purpose of publication, the energy-utilization efficiency shall be rounded off to the nearest even whole number

within a range of two percentage points, e.g., 72+1 percent.

COMMENTARY

The "two percent" criterion effectively allows an actual spread of

up to four percent and is an arbitrary value based on engineering

judgment.

CRITERIA

6.1.3 Procedure — A document shall be fvirnished to prospective equipment

purchasers, upon request, summarizing the methods used to determine the

efficiency, or referencing a national consensus voluntary standard test

procedure. Publication of such test methods or references by commercial

data services or trade organizations is deemed to satisfy the requirements

of this paragraph.

6,1, h Availability of Data — 'Where the data specified in 6.1.1 are not

immediately available, the manufacturer shall obtain and furnish the data

specified in 6.1.1,

6.1.5 Multi-Mode Operation — Where equipment is designed for multi-mode

operation (e.g., multi-speed forced warm air furnace with provision for a cooling coil), full-load energy-utilization efficiency (h/^) data shall

be provided for each separate mode of operation applicabli to the proposed

system.

55
6.1.6 Full-Load Efficiency Data — Full-load efficiency data shall be

firrnished as required under 6.1,1 for each different basic model and subtype numbered energy-significant equipment, except that a typical unit

may be selected to represent a group of units, each of which meets all

the following criteria:

(1) The function, capacity, and performance characteristics are similar,

(2) The basic model nimbers are the same,

(3) The units are all manufactured at the same plant.

(k) The units are sold to the same class of market. Examples of

different classes of market include residential, commercial, contractor,

retail, etc,

6.1.7 Identify Test Model — Where full-load energy-utilization efficiency

data are published for a group of similar units based on testing or analysis

of a typical imit, the actual unit type number tested or analyzed shall

be clearly identified,

6.2 REQUIREMENT

Energy- significant equipment used in building systems shall be designed

for efficient utilization of energy.

CRITERION

6,2,1 Minimum Full-Load Energy-Utilization Efficiency — No equipment

shall be specified in the design of new buildings which has a full-load

energy-utilization efficiency less than the equivalent of that presently

specified in nationally recognized voluntary standards,

EVALUATION

Verification that selected energy-significant equipment meets fullload efficiency requirements of applicable national consensus standards.

6.3 REQUIREMENT

Energy-significant equipment which requires periodic routine maintenance

actions to maintain efficient operation shall be furnished complete with

the necessary maintenance information.

CRITERION

6.3.1 Required Maintenance Actions — Required routine maintenance actions

shall be clearly stated as required and incorporated on a permanent label

affixed to a normally visible, external surface of the equipment. The

label may be limited to identifying required actions explained in greater

detail in a service manual. The label should identify by title and/or

publication niimber the service manual for that particular model and type

of product.

56
SYSTEM REQUIREMMTS

6.1+ REQUIREMEM'

HVAC systems shall "be energy-efficient,

CRITERIA

6,k,l System Design Heating/Cooling Capacity — The heating system(s)

for spaces in buildings intended to provide comfort for human occupancy

shall be designed with capacity to heat such spaces to TO °F at the -winter

outdoor design temperature (see 6,0,2.1). Similarly, the cooling system(s),

if provided, shall be designed with capacity to cool such spaces to 78 °F

at the summer outdoor design temperature (see 6,2.2.1). Heating/cooling

systems shall be capable of fimctioning to accomplish the requirements

for the control system in 6,k,2, 6,k,3, 6,h,k, 6.1^,5 and 6,5.9, as applicable,

EVALUATION

Review of HVAC system plans and specifications. Comparison of system

capacity design and building load calc\ilations

,

COMMENTARY

The design criteria of Chapter 6 do not limit the operation of HVAC

systems in buildings to the design indoor temperatures specified in

the criteria. For special cases such as hospitals or homes for the

elderly, requiring higher indoor temperatures, designers may wish to

size systems toward the high end of the 120 percent capacity range

allowed in 6,h,10,

CRITERIA

6,h,2 Temperature Control — Each space heating/cooling system shall be

provided with at least one readily adjustable automatic control for the

regulation of interior temperature. Each separate zone served by space

heating/cooling system shall be equipped with readily adjustable automatic control or conveniently located manual means for temperature regulation as required in 6,U,1, 6,U,3, and 6,5,9. Automatic comfort space

temperature controls shall be capable of being set to control heating at

least from 55 °F to TO °F and to control cooling (if cooling is provided)

at least from T8 °F to 85 °F, For space (or zone) temperatures between

TO °F and T8 °F the automatic control system shall be capable of being

set such that neither heating or cooling is provided. Combination, separate or multiple heating/cooling thermostats used to control heating and

cooling in any one room or zone shall be interlocked or the systems otherwise controlled to avoid simultaneous heating and cooling in any one room

or zone except for reheat as allowed in 6.1+.T. Means for shutting off the

heating or cooling to each zone shall be provided at a convenient location,

either within the zone or at an appropriate central building supervisory

monitoring station.

57
COMMENTARY

Central supervisory/monitoring systems can be used to meet the requirements of 6,h,2,

CRITERIA

6,h,3 Multiple-Zone Temperature Control

6.^.3.1 Single-Family Dwelling Units, Attached or Detached, and Mobile

Homes — At least one automatic temperature control as required in 6,h,2

shall be provided for each single-family dwelling unit and mobile home.

Each separate heating/cooling system in a single-family dwelling unit

shall be equipped with an automatic temperature control. Each separate

zone in a single-family dwelling rnilt or mobile home shall be provided

with either a readily adjustable automatic temperature control or sufficient conveniently located manually-adjustable devices capable of being

adjusted to both partially restrict and shut off the heating or cooling input

to the rooms or spaces in that zone. For single-family dwelling units or mobile homes, there shall be at least one separate zone in each emulative

full story height of the complete dwelling unit, excluding non-conditioned

basements and garages. Intermediate floor levels in split-level construction

are not considered fiill stories under this criterion,

6.^.3,2 Multi-Family Occupancies -— For m\ilti-family occupancies, each

individual living unit shall be considered separately for zoning purposes

and shall be provided with automatic space temperature control as required

in 6,k,2, For any single living unit, there shall be at least one separate

zone in each cumulative full story height of the complete living unit,

and each zone shall be provided with controls as required in 6,U,3,1,

Intermediate floor levels in split level construction are not considered

full stories under this criterion. Spaces other than living units in

multi-family buildings shall be treated as in 6,^,3.3.

6»h,3»3 Other Buildings — For other buildings, each space or group of

spaces to be conditioned for comfort and having different demands for

heating or cooling (because of varying solar loads, changing occupancies,

or other internal heat gains) shall be considered as a separate zone,

and shall be provided with automatic space temperature control as required

in 6,k,2, Each floor shall be^considered as at least one zone. For

buildings greater ^han 2000 ft of floor area per story, at least each

cumulative 2000 ft of floor area or fraction thereof of conditioned

space(s) on each floor adjacent to each major orientation of exterior ex- posure shall be considered as a separate zone and shall be provided with

automatic space temperature control as required in 6,i|.2, At least each

cumulative 3000 ft of floor area or fraction thereof of conditioned

space(s) on each floor having no exterior exposure shall be considered

as a separate zone and shall be provided with automatic space temperature

control as required in 6,k,2,

58
EVALUATION

Review of control systems plans and specifications,

COMMENTAEY

Areas or spaces vithin a building having different and varying demands

for heating and cooling (called zones) each need a means for controlling its temperature to prevent overheating (or overcooling) vhich

could be caused by having the system control in another space. In

addition, large open spaces require multiple zoning to provide ability

to operate the heating and cooling in only those areas being utilized.

Multiple zone control can be accomplished by modulating or varying

the heating or cooling effect being delivered to e|.ch zone or by

using separate systems for each zone. The 2000 ft of floor area

adjacent to an exterior exposure would accommodate, for example, 13

offices 10 ft by 15 ft or equivalent spaces,

CRITERIA

6»h,h System Design for Humidity Control — This document does not require

that heating/cooling systems be designed for or equipped with controls

for maintaining selected relative humidities in spaces or zones to provide

comfort for htunan occupancy.

If the heating system is equipped with means for adding moisture to maintain selected relative humidities in spaces or zones during heating operation, the capacity of the humidifying fxmction shall be designed to produce

relative humidities not higher than 30 percent at winter design conditions,

and the system shall be equipped with automatic humidity control(s) capable

of being set to control indoor relative humidity to 30 percent or lower.

If automatic control of indoor space humidity is provided as a part of

the cooling system design, the minimum indoor design relative humidity

shall be 60 percent. Means for raising humidity during cooling operation

is not required. The automatic hijmidity control system shall be capable

of being set such that cooling apparatus shall not operate for the sole

purpose of lowering the space (or zone) relative humidity below 60 percent.

See 6.i|.7 Reheat for limitations on use of new and recovered energy. The

control system shall be capable of being set such that neither the humidifying or dehumidifying functions of the HVAC system shall operate for the

sole purpose of space (or zone) humidity control in the range from 30 to

Go percent relative hiimidity.

59
6,U,5 Control Set-Back — All heating and cooling systems shall be equipped

with manually adjustable automatic timing or other devices capable of re- ducing the energy for heating and cooling during periods of non-use or alternate uses of the building spaces or zones served by such systems.

Buildings designed for continuous manual or automatic supervisory control

are considered to meet this criterion. The change in setting required to

reduce the heating or cooling effect (set-back) shall not cause energy

to be expended to produce the set-back conditions.

COMMENTARY

"Set-back" as used in 6,h,3 means the ability to change the automatic

temperature control setting to a value which will reduce the heating

or cooling produced during periods of reduced needs. Night set-back

during the heating season (e.g., a thermostat setting change from

70 °F to 55 °F) , shoTild not cause the cooling system to operate to

cool the building to the set-back temperature of 55 °F. Similarly,

'

^ under cooling conditions a set-back of the thermostat should not cause the heating system to raise the indoor temperature.

6,h,6 Simultaneous Heating/Cooling — HVAC systems serving one or more

rooms or zones in a building shall be so arranged that no one room or

zone can be heated and cooled simultaneously by the HVAC system except

for reheat as permitted in 6.^1,7.

COM^ffiNTARY

Separate heating and cooling systems should be interlocked or otherwise controlled to prevent simultaneous operation for one room or

zone. See Criterion 6.U,7 for limitation on reheat.

CRITERIA

6.U.7 Reheat -— Energy for reheat to accomplish either humidity or temperatiire control in any HVAC system shall be limited to the following

conditions

a. The total amount of new energy for either humidity or temperat\ire control used for reheat shall not exceed 5 percent of the

cooling system design capacity,

b. Recovered energy shall not be used for reheat for control of

temperature in excess of 10 percent of the cooling system design capacity.

c. Recovered energy may be used as needed for humidity control

in accordance with 6,h,h,

60
EVALUATION

Review of HVAC system plans and specification.

COMMENTARY

Use of excessive amount of either new or recovered energy for reheat

purposes for temperature control only (as opposed to reheat for

required humidity control purposes) is wasteful, and can be eliminated

by suitable distribution design. Use of small amounts of energy for

reheat for either temperature or humidity control in isolated areas may be more economical than providing a separate system.

CRITERIA

6,h,8 Energy Recovery — Each air exhaust-makeup system having more

than 1+000 cfm capacity which imposes non-beneficial heat gains or losses

on space conditioning systems shall employ energy recovery equipment if

either the winter or summer outdoor design temperature is 15 °F or more

lower or higher, respectively, than the indoor design temperature. This

equipment shall be capable of recovery of at least 50 percent of the

potential heating or cooling effect in the exhaust air, whenever the

temperature difference between the exhaust air and makeup air is 10 °F or greater. This requirement does not include contaminant-laden process ex- haust systems such as kitchen range hoods. Energy recovery systems shall

be capable of intermittent operation to accommodate beneficial outdoor

air conditions and the exhaust-makeup system shall be designed to operate

in accord with the design requirements whether the energy recovery system

is functioning or not,

COMMENTARY

Possible proximity of the air intakes and outlets can create a need

in design to assure the effective separation of the two air streams.

CRITERIA

6,k,9 Cooling with Outdoor Air — Each HVAC system with cooling capacity

greater than 120,000 Btu/hr in buildings not equipped with internal/external

zone heat recovery equipment shall be designed to use outdoor air for

cooling whenever cooling is needed at an outdoor temperature of 65 °F or lower, and when the enthalpy of the outdoor air is lower than that of the

indoor air,

6»h,10 System Sizing — HVAC systems and subsystems for a building shall

be selected such that the aggregate capacity at design conditions shall

not be more than 120 percent of the design heating, cooling, humidifying,

and dehiimidifying loads, standby equipment not included. The cooling

equipment in heat pumps may exceed the 120 percent requirement. The

heating equipment in heat pumps shall not exceed the 120 percent requirement . 61
EVALUATION

Examination of HVAC system plans and specifications. Comparison

of load requirements and system capacity data,

COMMENTAEY

The 20-percent over-design in system capacities indicated by this

criterion is an allowance for additional capacity that may be needed

following night-time change in thermostat setting and weather conditions above or below design levels. Generally, excessive oversizing

of system capacities results in less efficient operation. Standby

equipment as used in 6,k,10 refers to equipment designed and intended

for use when primary equipment is off-line due to maintenance or repair.

In order to minimize inefficiencies due to oversized system designs,

it shall be a design objective that the HVAC system be sized so as to be capacity limited at the stated design conditions. At outdoor

temperature extremes, the conditioned space temperature may drift

from the normal control point, and at or near extreme conditions,

the heating/cooling system may recover slowly after temperature

control setting change,

CRITERIA

6,U,11 Special Zones — Individual zones in large buildings or groups of

buildings served by a central HVAC system which (l) must maintain zone operation when main building loads are minimal or are shut down, or (2)

comprise unusual heating or cooling loads different from main building

loads, shall be served by the central system only if the central system

is designed to accommodate efficiently this special zone conditioning

by such means as efficient capacity reduction of refrigerating units and

boilers, adequate distribution zoning and zoning control, and use of

multiple subsystem elements (compressors, heaters, fans and pumps, etc);

otherwise, these special zones shall be equipped with separate space con- ditioning systems. For cumulative special zone loads equal to one-half

or more of the total system design load, the system shall be energy

efficient to at least 85 percent of the full-load efficiency (see 6.^4,13).

EVALUATION

Examination of plans and specifications with particular regard to

system design related to special zones and capacity reduction. Comparison of computed load requirements with selected equipment performance data,

CRITERION

6,h,12 System Performance Instrumentation -- Central heating and cooling

systems in buildings of more than 10,000 ft of floor area shall be

equipped with instruments or other indicating devices from which a deter62
mination can "be made of need for adjustment or service to maintain energyefficient operation.

EVALUATION

Examination of plans and specifications

COMMENTARY .

The indicating devices envisioned by this criterion include but are not limited to pressure gages, water level devices on boilers, flow

meters for various critical fluids , thermometers for flue and other

temperatiores , etc.

CRITERIA

6,h,13 Half-Load Efficiency — HVAC systems operating at l/2 rated load

at design conditions shall have an efficiency not less than 85 percent

of the system efficiency at full load operation at design conditions,

HVAC systems shall be designed and equipped with means for operating at

highest available system efficiencies as loads are reduced,

EVALUATION

Certification by designer or manufacturer of HVAC systems or major

subsystems,

CRITERION

6,h,lh Inter zone Heat Recovery — Each HVAC system with a cooling capacity

greater than 2^0,000 Btu/hr and which simultaneously provides heating to one or more zones and cooling to one or more different zones shall be designed to recover heat rejected by the cooling -unit whenever the heat

rejected is equal to at least 50 percent of the heat required by that system

at that time. In such systems, new energy shall be used only for supplemental

heating needed in excess of the recoverable heat,

EVALUATION

Comparison of design heating/cooling loads and system design capacities.

Examination of plans 9,nd specifications,

CRITERIA

6,h,l^ Ventilation by Mechanical Means — Outdoor air for mechanical

ventilation designed as a part of an HVAC system, for the purpose of

meeting normal respiratory and odor control needs in conditioned offices,

stores, meeting rooms, auditoriums, schools, living units and similar

spaces, shall be limited to 5 cfm per person. Outdoor air for mechanical

ventilation of conditioned corridors, lobbies, stairways, halls, laundries,

storage areas and similar public spaces in multi-family and other buildings

63
shall be limited to 2 air changes per hour for normal respiratory and

odor control needs. Special ventilating capacity in excess of 5 cfm per

person (or 2 air changes per hour) for the purpose of controlling smoking

contaminants, toxic gases, or other contaminants in the two classes of

conditioned spaces listed above shall be equipped with volume or cyclic

controls capable of remote adjustment if necessary, so that the ventilation rate can be readily adjusted to the amoimt needed for actual occupancy

conditions and shut off when not required.

These ventilation-limiting requirements do not apply to intermittentlyoperated locally-controlled ventilation units such as kitchen vent fans,

range hoods, bathroom fans, or to attic ventilating fans, or to the

sizing of ventilation systems using outdoor air for temperature control

in the occupied spaces, or to ventilation of non-conditioned spaces,

ASHRAE Standard 62-73, Standards for Natiaral and Mechanical Ventilation,

recommends special ventilation rates.

All mechanical ventilation systems shall be equipped with conveniently

located means for volume reduction or shut-off when ventilation is not

required,

COMMENTARY

If outdoor air ventilation rates in conditioned spaces greater than

shown are desired, consideration can be given to use of heat recovery

apparatus to minimize adverse loads on the space conditioning system

(see 6,h,Q,) The criteria values for outdoor ventilation rates were

were selected to save energy and yet provide needed ventilation.

For unusual non-toxic odor control, consideration should be given to

odor removal devices in lieu of increased ventilation rates.

64
COMPONENT AND SUBSYSTEM REQUIREMENTS

6.5 REQUIREMENT

Components of HVAC systems shall be energy-efficient.

CRITERIA

6.5.1 Fluid Transport Thermal Losses/Gains — See 6.5.2 and 6.5.3 for

minimum insulation requirements. In addition, the non-heneficial heat

gain/loss to/from each separate subsystem of piping and ductvork transporting liquids, vapors, or gases used for space heating/cooling shall

be limited to 3 percent of the heating/cooling thermal transfer design

capacity for the fluid in that subsystem. In any case, the aggregate

total non-beneficial gain/loss shall not exceed 5 percent of the total

system design capacity including all piping, ductvork, and unit casings,

etc., forming the entire heating/cooling system within the building, A

subsystem is a section of the entire system vhich contains only one type

of transfer fluid, such as hot or chilled water, steam, refrigerant,

brine, air, etc. Non-beneficial heat gain/loss means heat transfer into/

from non-conditioned space(s) or heat transfer into/from conditioned

space(s) in excess of or opposition to the energy requirement of that space,

EVALUATION

Examination of plans and specifications. Review of heat loss/gain

calculation.

COMMENTARY

A simple heating/cooling system may have only air ducts to consider

under 6.5.1. More complex systems may have chilled water lines,

steam or hot water lines, primary and secondary air ducts, etc, for

which the several subsystem losses or gains must be determined for

comparison with the design heating/cooling loads served by that

subsystem, and the total losses/gains compared with the total system

design capacity.

CRITERIA

6.5.2 Thermal Resistance of Ducts, Plenums, and Other Enclos;ires for

Air Systems-Heating — Air ducts and other surfaces installed in non- heated spaces (e.g., attics, garages, crawl spaces, etc.) shall be thermally insulated to provide^a surface-to-surface thermal resistance of not

less than R = AT/20 hr ft °F/Btu, where AT is the maximum temperature

difference between the air in the duct or enclosure and the surrounding

air, or shall be insulated to a value of R = i| hr ft2 °F/Btu, whichever

is greater,

COMMENTARY

Examination and evaluation of engineering calciilations.

65
CRITERIA

6,5,3 Thermal Resistance and Condensation Control, Ducts, Pipes and

Surfaces -- Cooling — For air ducts and surfaces installed in non-cooled

spaces, the thermal resistance criteria of 6,5.2 shall apply. Additionally, all ducts, pipes, and cool surfaces shall be insulated sufficiently

to prevent surface condensation under operating conditions. The insulation shall be protected by a vapor barrier, maximum permeance 0,1 perm,

and all joints shall be sealed against vapor penetration.

EVALUATION

Engineering examination and evaluation of the design and design calcialations, ASTM recommended practice E2U1-68 for general design information, ASTM Test Methods E96-66 (Procedures A, dry cup) for

materials such as paper, plastic films and other sheet materials that

are less than l/8-inch thick shall be used for the purpose of evaluation,

COMMENTARY

Access doors and similar removable panels in duct system enclosures

should be tight fitting (see 6,5.^) and insulation at joints of such

doors should be adequately sealed to minimize moisture entering the

insulation,

6,5.^ Duct Air Leakage — The entire duct system for HVAC systems shall

not leak more than 5 percent of the design air flow at design duct pressure,

EVALUATION

' Review of duct plans and specifications. Tests patterned after

SMACNA procedures,

COMMENTARY

/ Medium and high pressure ducts are customarily designed for duct

, _ leakage of 1 percent or less. Duct air leakage in any system defeats

the intended function of the system. Leakage in non-conditioned

areas is a total loss and in addition, leakage even in conditioned

areas may prevent adequate delivery to intended locations,

CRITERION

6,5.5 Automatic Ignition — Automatically controlled gaseous or liquid

fuel-fired devices providing space heating shall be equipped with means

for fuel ignition which operates only when the burner is required to

operate. Automatic ignition devices shall conform to life safety standards , such as

ANSI Z21,20 Automatic Burner Ignition and Safety Shut-off Devices

ANSI Z226,l Primary Safety Controls for Gas and Oil Fired Appliances

66
EVALUATION

Certification or listing of selected ignition devices,

6.5.6 Off- Cycle Air Flov Heat Loss — ComlDUstion heating equipment with

greater than 250,000 Btu/hr input shall be equipped with devices to minimize air flow through the combustion chamber during burner off-cycles.

These devices shall be safety listed. All vented fireplaces shall be

equipped with tight closing dampers or other comparable draft closures,

EVALUATION

Examination of proposed heating system design. Certification or listing

of stack or combustion chamber off-cycle air flow control devices,

6.5.7 Cooling Efficiency - Electric Motor-Driven Cooling Systems —

Electric motor-driven cooling systems rated at standard rating conditions

as listed in ARI 210-67 and including all system fan and pump motors

shall have a ratio of net system cooling capacity to energy input of

not less than 8,0 Btuh/watt for cooling capacities of 60,000 Bttih or greater and 7.0 Btuh/watt for cooling capacities less than 60,000 Btuh,

All cooling systems with rated output greater than 2ii0,000 Btuh shall

have a ratio of system capacity to energy input of not less than 8,5

Btuh/watt,

EVALUATION

Certification of selected equipment,

COMMENTARY

The term "Btuh/watt" is used here as a means of expressing efficiency

of electric motor-driven cooling equipment because of its adoption

by the industry. As used it means (Btu/hr )/watt , where "Btu/hr" is

the net cooling capacity of the complete system at its defined rating

condition, and "watt" is the electrical input rate to the complete

system at the same conditions. The values of "Btuh/watt" do not

include correction for electric power generation, transmission and

distribution efficiency for either the compressor motor or for other

auxiliary electrically-operated elements. If electric power generation transmission and distribution requires 12000 Btu/kwh, the values

of 7.0, 8,0 and 8,5 "Btuh/watt" indicate net cooling capacity-toenergy source input COP values of 0,58, 0,67, and 0,71 respectively.

Net cooling as used here includes both sensible and latent heat,

CRITERIA

6.5.8 Cooling Efficiency - Heat-Operated Cooling Systems — Heat-operated

cooling systems with a COP of less than 0,5 at standard rating conditions

including all system auxiliaries, and fan and pump motors (determined in

accordance with Appendix 2 of Chapter 6) shall not be used to provide more

than 25 percent of the design cooling requirement unless recovered energy,

solar energy or energy derived from waste processes is used as the principal energy source,
EVALUATION

Comparison of selected system performance data and efficiency of

energy source. Review of calculated overall system COP,

COMMENTARY

Pending availability of standard industry rating procedures for

determining the overall system net cooling capacity-to-system energy

input COP, a procedure is given in Appendix 2 of Chapter 6. Net

cooling as used here includes "both sensible and latent heat. Using

the procedure in Appendix 2, as an example, a heat-operated cooling

system vith a unit COP of 1,0 or more, energized by a steam supply

of at least 70 percent efficiency, and with system control, condenser

and cooling circuit pover inputs equal to not more than 20 percent

of the chiller capacity would satisfy the requirement of 6,5,8 for

use of "new" energy.

68
6,5.9 Electric Resistance Heating— This dociiment does not limit the

use of electric resistance heating systems as the principal means of

comfort space heating in the following buildings:

-all "buildings in geographic areas having 2000 heating degreedays or less annually

-buildings utilizing electric energy for heating which is generated either by solar or wind-produced energy, by combustion

of waste materials, by recovery of waste energy, or by a total

energy system conforming to the definition in Chapter 3.

2 -buildings smaller than 500 ft of floor area,

-mobile homes

For all other buildings the use of electric resistance heating as the

principal means for comfort space heating shall be limited to the following conditions

1, Buildings shall have a design heat loss at least 15 percent

lower than permitted in Chapter 5

2, In addition to the minimum temperature control requirements

for any heating system in 6,h,2 and 6,U,3, (a) one or more

readily-adjustable automatic temperature controls as required

in 6,h,2 shall be provided for control of each zone described

in 6,U,3,1, 6,^,3,2, or 6,^,3.3 as applicable, and (b) at

least one readily-adjustable automatic temperature control

as required in 6.U,2, or sufficient readily-adjustable manual

devices capable of being set to both partially restrict and

shut off. Such heating input controls shall be provided (l) in

each separate heated room or other enclosed spaces of more than

100 ft^ of floor area which has one or more exterior walls,

and (2) in ^ach heated room or other enclosed space of more

than 500 ft of floor area, having no exterior walls. If in

response to 2(b), each separate heated space in a zone is

provided with automatic control, 2(a) is satisfied, and a separate zone control is not required,

EVALUATION

Examination of plans and specification.

COMMENTARY

Electricity is a highly refined source of heat which, in typical

generating plants, has already lost about two thirds of the

available potential energy of the fuel used in the generating

process by the time it reaches the electric heating load in a building. Because of this loss in energy potential, logic indicates that a highly refined form of energy should be applied more

carefiilly at the point of use, 6,5.9 (2) is intended to eliminate

unnecessary input of this highly refined heat energy when solar or other heat gains reduce the demand for heatings,

69
Central electric resistance varm air or hydronic systems can satisfy

the automatic zone temperature control requirements by using individual

automatically-controlled heat outlets or fixtures in all the spaces

in a zone.

The rationale for not recommending a differential reduction of heat

loss even greater than 15 percent for electric resistance heating

is based on the following:

(1) The thermal resistance criteria in Chapter 5 may already

be equal to or greater than previously existing guidelines for electrically heated buildings, and the technical/esthetic feasibility of

requiring thermal resistance differential requirements much greater

than 15 percent is in doubt for some climatic regions,

(2) The criteria of 6,5,9 do not limit using forms of

electrically energized heating other than the resistance type. In

many applications, an electric driven heat pump system uses electricity

more efficiently than does electric resistance heat, and its use

shoiild be encouraged,

(3) Depending upon the application, anyvhere from one-fifth

to one-half of the soTorce potential energy is lost in direct heat

conversion systems using fossil fuels. The 15 percent criteria

brings the efficiency of electric resistance heat within the

same general area as that of the low end of the range for fossil

fuels.

The exception made for mobile homes is based on two factors:

(1) Dimensional space and weight limitations due to

transportation requirements,

(2) Mobile homes typically use central forced warm air

heating systems because this type of system is adaptable to

various fuels used at different installation sites. The specific

site (and fuel) is unknown at the time of manufacture. Under

these conditions, it is usually unfeasible for the mobile home

manufacturer to use those forms of electric resistance heating

that readily lend themselves to zone control,

CRITERIA

6,5.10 Heat Pumps — Electric motor driven vapor compression heat pumps

with supplemental electric resistance heat shall be sized to provide by

compression at least 60 percent of the calculated annual heating requirement for the building or space served, A control shall be provided which

can be set to prevent use of supplemental electrical resistance heat at

outdoor temperatures above 32 °F, Air-source heat pumps shall have

seasonal performance factors (S,P,F,), including supplemental heating of:

70
Design Temperature, °F S.P.F.

> 35

20 to 35

0 to 20

-20 to 0

> 2.25

> 2..0 > 1.5

> 1.25

S.P.F. = X

Y+Z

where

X = heat delivered to space during heating season, kWh.

Y = energy to motors during the heating season, kwh.

Z = supplemental heat during heating season, k¥h.

EVALUATION

Comparison of calculated annual heat loss and certified seasonal

performance factors. Review of design calculations, plans, and

specification.

COMMENTARY

Heat pump seasonal performance factors (S.P.F.) can he computed

as shown below from building heat loss, heat pump performance

characteristics, including supplemental heat, and seasonal heating hours below 65 °F for outdoor air temperature increments of

5 °F. Engineering Weather Data AFM 88-8, Chapter 6, lists heating season hours at 5 °F intervals for many locations in the

U. S. This information is also available from the U, S. Weather

Bvireau, Using data such as is furnished by several heat pump

manufacturers, the analytical procedure may consist of a summation

by 5 °F increments of the building heat loss, the varying steady-state

heat pump performance characteristics and hours of operation, and hours

of required supplementary heat operation. A computerized dynamic

analysis is not necessarily required. The S.P.F. shall take into

account all system energy requirements, including defrost operation

and supplementary heat. Specifically, the items, X, Y, and Z

necessary for determining S.P.F. can be calculated in tabular form

from the following information:

A - Outdoor temperature range, °F

outdoor air temperature increments of 5 °F below 65 °F

B - Seasonal heating hours for A, hrs

C - Average building heat loss for A, Btu/hr

D - Heat pump capacity for A, Btu/hr

E - Percent rimning time for heat pump, %

If OD, E = 100; otherwise E = 100 x C/D

F - Rate of energy input to heat pump for A, kW

G - Energy input to heat pump, kWh

G = B X E X F/lOO

H - Energy input to building from electric resistance heaters, kWh.

If C<D, H = 0; otherwise H = B x (C-D) 73^+12.

J - Energy input to building from heat pinup, kWh.

J = E X D/3^1200

71
Summing over the outdoor air temperature increments gives

Y = EG

Z = EH

X = EJ + EH

for substitution in the definition for S.P.F,

The purpose of the control to prevent use of supplemental electric

resistance at outdoor temperature above 32 °F is to eliminate unnecessary use of the less efficient supplemental heating at times

vhen the heat pump can supply adequate heating. It also assures

that failiore of the heat pump will be detected if it occurs. The

temperature of 32 °F will permit use of supplemental heating to

prevent freezing damage in the event of heat pump failure. The

32 °F temperature is not intended as a balance point requirement

for determining heat pump size.

72
APPENDIX 1

LISTING OF STANDARDS FOR HVAC

EQUIPMENT WHICH INCLUDE EFFICIENCY

ANSI Z21.ll - 19 Tl

Gas-Fired Room Heaters

Volume I (Z21.11.1) Vented Room Heaters - Efficiency TO percent "based on total volime of gas.

Volume II (Z21.11.2) Unvented Room Heaters - 1971 - Performance - No number for efficiency.

ANSI Z21.13 - 1972

Gas-Fired Steam and Hot Water Boilers

Shall have a thermal efficiency of 75 percent based on total heating

value of the fuel.

ANSI Z21.3^ - 1971

Gas-Fired Duct Furnaces

Thermal efficiency of 75 percent based on total heating value of

fuel.

ANSI Z21.^;3 - 1968

Unvented Gas-Fired Infrared Radiant Heaters

Radiant efficiency of at least 35 percent.

ANSI Z21.U1; - 1971

Gas-Fired Gravity and Fan Type Sealed Combustion System Wall Furnaces

Gravity type - Efficiency 70 percent based on total heating value of

fuel.

Fan type - Efficiency 75 percent based on total heating value of fuel.

AJTSI Z2lM -

Gas-Fired Gravity and Forced Air Central Furnaces

Thermal efficiency gravity 70 percent based on total heat value of

gas.

ANSI Z21.1;8 - 1976 (U8a - 1968

Gas-Fired Gravity and Fan Type Floor Furnaces

Gravity type - Efficiency 65 percent based on total heating value of

fuel.

Fan type - Efficiency 70 percent based on total heating value of fuel.

73
MSI Z21.51 - 1971

Vented Gas-Fired Infrared Radiant Heaters

Efficiency - shall have a radiant efficiency of at least 35 percent,

ANSI Z21.52 - 1971

Gas-Fired Single Firebox Boilers

Steam and hot water boilers shall have efficiency 75 percent based on total heating value of fuel.

ANSI Z21.53 - 1967

Gas-Fired Heavy-Duty Forced Air Heaters

Shall have thennal efficiency of not less than 75 percent based on total heating value of fuel,

ANSI Z91,l - 1972

Oil-Povered Central Furnaces

Performance - Output capacity in Btu/hr 0.75 times input.

74
APPENDIX 2

PROCEDURE FOR DETERMINING COEFFICIENT OF PERFORMANCE (COP) FOR

HEAT-OPERATED COOLING SYSTEMS MEETING THE REQUIREMENTS OF 6.5.8

At the present no standard industry rating conditions have been promulgated for heat-operated cooling units. Unit performance shall be based

on the following rating conditions vhich shall be considered "standard"

for this document:

Leaving chilled-water temperature kk °F

Chilled water AT across chiller 10 °F

Temperature of condensing water

entering \init 85 °F

Condenser water flow 3.6 gpm/ton of condenser

load

Steam inlet pressure (single effect) 12 psig

Entering hot water temperature

(single effect) 270 °F

Hot water AT across unit (single

effect) kO °F

Steam inlet pressure (double effect) 123 psig or ihh psig

Entering hot water temperature

(double effect) 370 °F

Hot water AT across unit (double

effect) ho °F

Outdoor air Temperature, DB 95 °F

Outdoor air temperature, ¥B 75 °P

Indoor air temperature, DB 80 °F

Indoor air temperature, WB 67 °F

The COP of the proposed system based on the above conditions shall be

determined by:

COP = net refrigerating effect

rate of total energy input

where the net refrigerating effect is the rate of heat removal from the

chilled water passing through the chiller minus the power input to all

cooling circuit fans and pumps, and the rate of total energy input is

the sum of all power used by the unit accessories, the condenser water

cooling process pumps, fans, etc plus the product of the rate of fuel

consumption and the higher heating value of the fuel used as the source of heat energy to the absorption unit itself, all expressed in consistent units. For the COP determination, energy input to all auxiliary

devices (other than the absorption unit) such as controls, fan and

pump motors shall be based on the power input to the various devices.

Where steam or hot water is used as the unit energy source, the rate

of energy input to the unit shall be based on the fuel used to produce

the steam or hot water. If the unit is direct-fired, the rate of energy

input to the -unit shall be the product of the rate of fuel consumption

and the higher heating value of the fuel.

75
CHAPTER 7

SERVICE WATER HEATING REQUIREMENTS

7.0 REQUIREMENT

Hot water for domestic and sanitary purposes shall be generated and

delivered in a manner conducive to saving energy.

CRITERIA

7,0.1 Insulation — All service hot water storage tanks and pipes

containing heated water shall be insulated. Minimum insulation, values

for storage tanks and piping shall be R=6 and R=4, respectively,

EVALUATION

Review of system plans and specifications.

COMMENTARY

The heat loss of domestic hot water systems <iue to interaittent

usie and from the piping or recirculating systems is significant,

and adds to the cooling loads in spaces requiring cooling.

CRITERIA

7.0.2 Pump Operation — Circulating service hot water systems shall

be so arranged that the circulating pump(s) can be turned off when

the portion of the building served by that pump is not in use.

7.0.3 Combination Service Water Heating/Space Heating Boilers — Service

water heating equipment shall not be dependent on year-round operation

of boilers otherwise required only for winter space heating if the boiler

capacity is more than 120 percent of the design service water heating

demand load.

COMMENTARY

A boiler may operate at low efficiencies during summer months if

used to provide domestic hot water under conditions where the

water heating load is small in relation to the space heating load.

CRITERIA

7.0. A Temperature Control — Service water heating systems shall be

equipped with automatic temperature controls capable of adjustment

to the lowest acceptable temperature setting for the intended use. These settings shall be 120 °F or less for domestic dishwashing/clothes

washing machines and 180 °F or less for commercial application.

76
7.0.5 Electric Resistance Service Water Heating — For systems

serving more than four single-family living units, service water

heaters shall not use electric resistance heating unless 1) electricity

Is used as the principal means for heating the building, or 2) the

electric power used for water heating Is generated either by solar

or wind-produced energy, by combustion of waste materials, by recovery

of waste energy, or by a total energy system conforming to the

definition in Chapter 3.

CRITERIA

7.0.6 Fossll-Fuel-Flred Service Water Heating — Fossll-fuel-f Ired

service water heaters with input heating capacities greater than

250,000 Btu/hr shall be equipped with automatic ignition (which

operates only when the burner is required to operate) and off-cycle

air-flow heat-loss control devices. Each of these devices shall

be safety listed.

77
APPENDIX 1

LISTING OF STANDARDS FOR SERVICE WATER

HEATING EQUIPMENT WHICH INCLUDE EFFICIENCY

ANSI A21.10 - 1971

Gas Water Heaters

Volume 1 (Z21.10.1) Automatic Storage Type Water Heaters With

Inputs Less Than 75,000 Btu/hr - Performance Test.

Volume II (Z21.10.2) Side-Arm Type Water Heaters

Volume III (Z21.10.3) Circulating Tank, Instantaneous and Large

Automatic Storage Type Water Heaters - Thermal efficiency

of not less than 70 percent based on the gas input.

78
CHAPTER 8

ELECTRICAL DISTRIBUTION AND

POWER FACTOR REQUIREMENTS

8,0 REQUIREMENT

The electrical distribution system in a building shall be designed for

efficient distribution of energy from the service entrance to the outlets,

and shall not impose inefficient conditions on the electric utility distribution system.

CRITERIA

8,0.1 Pover Factor — In each building having one or more electric ser- vices aggregating 600 amperes or more, a graphic (recording) pover factor

meter shall be provided during the first year of operation and the power

factor shall be continuously monitored. If the power factor falls below

0,9 lagging for periods accumulating one-half hour in any 2U-hoiir period,

power factor corrective devices shall be installed to raise the power

factor to 0,9 or higher. If after the initial power factor correction

additional reactive loading is introduced in the building, the power

factor shall be continuously monitored again for a period of one year,

and additional correction performed to meet the above criterion.

It is recommended that the electric utility be responsible for installation,

upkeep, and removal of the graphic power factor meter.

COI-IMENTARY

Low power factor causes greater losses in transmission and distribution of electricity. Typically, m.ost commercial and public

buildings diiring the non-air conditioning season have a power

factor of at least 0.9s unless the power factor is reduced by reactive loads such as fluorescent lighting units and elevator motors.

Where the loads of the building are such that they create a power

factor at the building service of less than 0,9 lagging, capacitance

corrective devices can be placed at those loads or at the feeders

to those loads. Power factor correction at the generating plant does

not prevent the losses associated with transmission of the reactive

power component through the distribution network,

CRITERION

8,0,2 Power Factor Correction for Cooling Equipment — In a building

which is wholly or partly cooled with one or more units aggregating

120,000 Btuh or higher, power factor correction devices shall be provided so that the power factor of the entire air conditioning system,

including fans, shall be not less than 0,9 lagging at any load condition.

EVALUATION

The designer shall indicate on the plans a calciilation of the lagging

kilovars of the air conditioning equipment, the corrective leading

kilovars provided, and the resultant power factor of not less than

0.9. 79
COMMENTARY

Pover factor improvement, especially during periods of peak summer

load, will reduce peak demand in the public utility peak power output and reduce losses in the transmission and distribution system,

CRITERIA

8,0,3 Service Voltage — In each building having one or more electric

services aggregating 600 amperes or more, the service voltage shall be

nominally 2TT/^80 volts, 3-phase, U-wire, or i+80 volts, 3-phase,

3-wire, In such buildings, the portion of the lighting system defined

as "efficient" under 9.1.1 shall be served directly at 277 volts or higher, and transformers shall be used only to serve appliance loads,

or other loads not designed to operate at 277 volts. Manufacturers

shall make available to prospective building owners or their representatives data on the full-load efficiency of such transformers,

'

: EVALUATION

Verify by inspection of the plans submitted for approval.

COMMENTARY

Higher service voltages mean lower losses in the distribution of

electricity,

CRITERION

8,0,^ Voltage Drop — In any building, the combined voltage drop in

feeders and branch circuits shall not exceed 3 percent of the service

voltage,

EVALUATION

The plans submitted for approval shall have a tabiilation of feeders

and branch circuit voltage drops. The voltage drop summation of

the longest and the most heavily loaded feeder and branch circuits

should not be more than 3 percent of the service voltage,

COMMENTARY

Articles 210-6(d) and 215-3 of the National Electric Code define

the size of the feeders and branch circuits so that the total

voltage drop does not exceed 5 percent of the service voltage.

The energy lost in the distribution system principally goes into

I^R losses in the feeders, branch circuits, transformers and

switch gear, and is converted into heat which is generally not

credited to useful effect, and adds to the comfort cooling load.

The above criterion reduces the voltage drop loss by up to 2 percent, and to that extent, energy will be conserved.

80
CRITERION

8,0,5 Light Switching — In any space requiring two or more branch

circuits for lighting, switching shall be provided for each circuit

or for portions of each circuit, so that a portion of the lighting system

adequate for custodial or maintenance purposes or for effective com- plementary use of natural and artificial lighting may be operated

without switching on/off all of the lighting in that space,

EVALUATION

The plan examiner shall look at the diagrams to make sure that

there is enough switching provided. He should determine that there

is at least one switch in each room.

CRITERION

8.0,6 Electric Meters — In any multi-tenant building, the electric

energy to each tenant shall be metered separately for energy consumed

in his portion of the building. It is recommended that each tenant also

be billed separately for the energy he uses. Condominiums shall be

included as multi-tenant buildings. Hotels, college dormitories, and

other transient facilities are excluded from the provisions of this

paragraph

,

EVALUATION

Examine plans to determine that each tenant has his own meter.

COMMENTARY

There is some evidence that a significant reduction in energy

usage occurs when tenants pay directly for the energy they constune.

81
CHAPTER 9

LIGHTING REQUIREMENTS

9,0 REQUIREMENT

In any space -within a building, the permissible level of maintained illumination shall be based upon the use for which the space is intended,

CRITERIA

9.0,1 Task Lighting — The design criteria for the level of illumination

in the immediate area of a specific task shall be no greater than that

recommended by the Illumination Engineering Society in the lES Lighting

Handbook, 5th ed, , for that task,

9.0,2 Local Lighting — Task illumination shall be produced by luminaires

arranged to ill"uminate the immediate task area, and such luminaires shall

be individually switched. This requirement shall not apply^where room

occupancy is such that the averaged occupied space is 50 ft or less per

occupant.

9.0.3 General Lighting — The general level of illumination in a space

surrounding the task area shall be not more than 1/3 of the task level,

Where more than one task level occurs in a space, the general level shall

be not more than 1/3 of the average level of task illumination in the

adjacent task spaces,

9,0,U Noncritical General Lighting — In the areas within corridors,

stairways, toilets, lobbies, and the like, where no specific visual task

occurs, the level of illumination shall be no more than 1/3 of the average

level of general illi:miination in the adjacent task spaces, but not less

than OSHA recommended levels for safety.

9.0.5 Lighting Calculations

9.0.5.1 Compliance with the requirements and criteria of 9*0 and 9.1

shall be determined by calculation of maintained illumination, following

the procedure recommended by the Illuminating Engineering Society in the

lES Lighting Handbook, 5th ed.

9.0.5.2 The following initial reflectances shall be used in calculation

of maintained illumination:

1) Ceilings, Q0%

2) Walls, 50^

3) Floors, 20^

COMMENTARY

Where higher reflectances are provided, increased lighting levels

will be permitted in proportion. Where lower reflectances are provided, no increase in wattage will be permitted for the purposes of

bringing lighting levels up to those specified above.

82
9.0.5.3 The following shall "be used in calculating Light Loss Factors:

1) Area atmosphere to be "clean"

2) Time "between cleaning, 12 months

3) Lamp "burnout factor = 1,0

h) All recoverable factors = 1.0

9,0.5.^ Coefficients of utilization shall be no lower than those given

in the lES Lighting Handbook, 5th ed. , for the existing conditions and

type of luminaires.

9,1 REQUIREMENT

Only efficient lamps shall be used for general illumination and local task

illumination, except as provided below in 9.1.3 and 9.1.^.

CRITERION

9,1,1 Efficient Lamps — Lamps shall be defined as those which produce

at least kO lumens per watt input, including ballast losses, at the

rated initial output, defined herein as "efficient lamps". This definition is used in 9.1.^ as a basis for determining lighting load.

COMMENTARY

Some lamps in common use operate with a relative efficiency as low

as l/h that of other commonly available lamps. The objective of

the criteria of 9.1.1 is twofold:

1) To provide a basis for computing the total wattage allowed

for lighting under 9.1.^.

2) To restrict the use of inefficient lamps to special usages

(9.1.3) and in a trade-off mode with more efficient lamps as provided

under 9.1.^.

CRITERIA

9.1.2 Other Lamps — To the extent that lamps producing less than ^0

lumens per watt are used, the general lighting in the space shall be

reduced by an equal number of watts,

9.1.3 Exceptions — The criteria of 9.1.1 and 9.1.2 shall not apply to

the following:

1) Private residences, except for kitchens, bathrooms, and la'undry areas

.

2) Private apartments in apartment houses, except for kitchens

and bathrooms in the apartments, and public spaces such as lobbies,

halls, stairways, laundry and utility rooms, and basement areas generally,

over 60 watts""" ^^^'^^^» ^^^^ closets, requiring only one lamp of not

83
h) Auditoriums and stages vhere dimming is essential to the use

of the space,

5) Projectors.

6) Portable devices,

7) Luminaires for medical and dental diagnostic, surgical, or therapeutic purposes,

8) Highlighting applications, such as localized lighting of -work

stations, sculpture exhibits, art exhibits, and individual items of

display merchandise,

9) Specialized lighting applications (color matchingsj vhere

electrical interference cannot be tolerated),

9,1,^ Lighting Alternatives — The total watts used in a .building for

interior lighting purposes shall be no more than that which wo^lld have

been required had all spaces been illuminated with efficient lamps,

efficient liminaires, and reflectances, as defined above. Performance

specifications of lamps and luminaires shall be that given in the fifth

edition of the lES Lighting Handbook,

9.2 REQUIREMEFT

Use of luminaires providing for heat removal or heat recovery shall be

encouraged.

CRITERION

9.2.1 Heat Removed/Recovered from Luminaires ~ Where the heat from lamps

is in part removed by a heat transfer medium which does not enter the

occupied spaces, each Btu so removed may be offset by 1/2 Btu of additional

permitted energy input to the lighting system for ill\maination purposes,

provided that at least 30% of 'energy so removed can be recovered for useful

heating purposes elsewhere or for reheat in humidity- control equipment, and

provided that the remainder of the energy removed is not transmitted as additional load to the cooling system.

EVALUATION

- The evaluator may determine from standard procedures when available,

or manufacturers' recommendations when industry or national standards

are not available, the total Btu exhausted from luminaires.

COMMENTARY

All energy used for lighting ends up as heat, and energy saved by

removing this load from the air conditioning load should be rewarded.

The criteria of 9 •5 is not intended to encourage the use of more

energy in lighting for the purpose of heating building space.

84
9.3 REQUIREMENT

The energy expended for exterior lighting shall be minimized by basing

the maximum level of maintained illiimination upon the use for -which the

space is intended and by using efficient light sources as defined in

9.1.1.

CRITERIA

9.3.1 Lighting Levels

9.3.1.1 Maintained levels of illumination for exterior lighting shall

be no greater than that recommended by the Illuminating Engineering

Society in the lES Lighting Handbook, 5th ed. , for that area classification.

9.3.1.2 Signs and facade lighting, 500 watts, or 1% of total interior

lighting load of the building, whichever is greater.

9.3.1.3 Continuous burning gas lamps shall not be used to provide illumination or decoration.

9.3.2 Lighting Calculations — Calculation of illumination shall follow

the procedure recommended by the Illuminating Engineering Society (lES)

Lighting Handbook, fifth edition.

85
CHAPTER 10

ENERGY REQUIREMENTS FOR BUILDING

DESIGNS BASED ON DYNAMIC ANALYSIS

10.0 REQUIREMENT

Alternative "building designs shall be accepted that can be shown to save equivalent amounts of energy without following each and every detailed

requirement of Chapters 5 through 9 of this standard,

CRITERIA

10.0,1 Equivalent Annual Energy Consumption — Under the provisions of

this chapter the designer may propose any design of building and energysaving systems for which the integrated annual energy use is equal to or

less than the corresponding annual energy use of a similar system designed

to meet the requirements of chapters 1-9 of this standard. Comparison of

the two designs shall be based on annual energy profiles of both systems

covering heating, ventilating, cooling, lighting, and service water

systems. The criteria for this comparison process are illustrated in

Figure 10-1,

10,0,2 Do cument at i on ~ Building owners or their representatives who

desire to use an alternative building design based on dynamic analysis

shall provide detailed technical data and analyses as necessary to

verify that the design complies with the requirements of this chapter.

This report shall include details of the annual energy consumption

analysis for the building service systems prepared by a registered

professional engineer or architect, recognized as an expert in the design of the type of structure and systems submitted.

10,0,3 Basis for Comparison — The building and service system design

selected as a basis for the reference energy budget shall meet the re- quirements of Chapters 1 through 9 of this document and shall be one that

is commonly employed for the proposed type of occupancy and geographical

location,

lO.O.ii Commonality — The comparative analysis for evaluation shall

include the building exterior envelope design, common climatic data, common operational occupancies and schedules, common energy systems

characteristics, common efficiency assumptions, and comparable building

shape and height,

10,0,5 Analysis Procedure ~ The energy consiimption analysis for the

design forming the basis of comparison and for all energy-using systems

considered as alternatives under the provisions of this chapter shall

be conducted according to the following procedure;

86
10,0,5.1 The biiilding heating and cooling load analysis that is used as the basis for the energy consximption analysis shall be performed in ac- cordance vith the procedures recommended by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Task Group

On Energy Requirements in the document entitled "Procedures for Determining

Heating and Cooling Loads for Computerized Energy Calculation", or equivalent

.

10,0, 5.2 The simulation of the building and its systems shall cover the

entire range of operation for a test year. Simulation of the HVAC system

shall be performed in accordance -with the ASHRAE Task Group publication

entitled "Proposed Procedures for Sim-ulating the Performance of Components

and Systems for Energy Calculation", Operational characteristics of the

building, including temperature and humidity levels, lighting schedule,

occupancy schedule, and schedule of outside air being introduced throiigh

the ventilation system shall be included. The simulation of the compponent equipment shall include operation at part-load as veil as fullload conditions. Manufacturers' data shall be used where available and

all thermal performance characteristics of the energy-significant com- ponents as well as thermal characteristics of the building shall be

given in the report specified in 10,0,2,

10,0,5.3 The particular computer program or calculation procedure that

is used to estimate annual energy consumption shall be reviewed and

evaluated by the registered professional engineer or architect referenced

in 10,0,2, An analysis procedure which deviates from the criteria of

10.0,5.1 and/or 10,0,5.2 shall be allowed provided that it is approved.

COMMENTARY

These criteria allow maximum flexibility to the designer to provide

performance solutions without necessarily complying with the detailed

criteria for the building envelope, mechanical, electrical, lighting,

service water, or other systems within a building.

87
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CHAPTER 11

REQUIREMENTS FOR BUILDINGS UTILIZING

SOLAR OR WIND POWERED ENERGY SOURCES

11.0 REQUIREMENT

An energy bonus shall be granted to buildings designed to reduce usage of

mineral or hydroelectric energy sources by using solar or wind powered

energy sources to supply part of all of the building energy requirements.

CRITERIA

11.0,1 Energy Estimate — The computed annual energy consumption of a building and its service systems when employing part or all solar or wind powered energy sources according to the Criteria of this chapter

shall be allowed to exceed the reference energy budget obtained by com- puting the annual energy consumption of a system employing only mineral

or hydroelectric energy sources by the amount of 50 percent of the energy

obtained from solar or wind powered sources. The criteria for claiming

such an energy bonus is given in this chapter and the steps illustrated

in Figure 11-1, Windows shall not be considered a solar energy source

for the purposes of this chapter. Use of windows to make more effective

use of solar energy can be recognized under Chapter 10.

11,0,2 Documentation -- Building owners or their representatives desiring

to claim the energy bonus that is permitted in 11,0,1 shall provide a report giving detailed technical data and analysis as necessary to verify

that the design complies with the requirements of this chapter. This

report shall include details of the energy consumption analysis for the

building service systems prepared by a registered professional engineer

or architect, recognized as an expert in the design of the type of structure and systems submitted,

11,0,3 Basis for Comparison -- The building and service systems design

using mineral or hydroelectric energy source(s) and selected as a basis

for the reference energy budget shall meet the requirements of Chapters

1 through 9 of this document and shall be one that is commonly employed

in the proposed type of occupancy and geographical location,

11,0,4 Commonality -- In designing the service systems using part or all

solar or wind energy sources, only those components of the building and

service equipment that must be modified to utilize such energy may be

different from those used to calculate the total annual energy budget.

Common climatic data, common occupancies and use schedules, and common efficiency assumptions for identical components shall be used in the

two cases,

11,0,5 Analysis Procedure -- The energy consumption analysis for both

the mineral or hydroelectric and the solar or wind powered energy-using

systems shall be conducted according to the following procedure.

89
11.0.5,1 The building heating and cooling load analysis that is used

as the basis for the energy consumption analysis shall be performed in

accordance with the procedures recommended by the American Society of

Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Task

Group on Energy Requirements in the document entitled "Procedures for

Determining Heating and Cooling Loads for Computerized Energy Calculation,"

or equivalent,

11,0.5.2 The simulation of the building and its systems shall cover

the entire range of operation for a test year. Simulation of the HVAC

system shall be performed in accordance with the ASHRAE Task Group publication entitled "Proposed Procedures for Simulating the Performance of

Components and Systems for Energy Calculation". Operational characteristics of the building, including temperature and humidity levels, lighting

schedule, occupancy shcedule, and schedule of outside air being introduced

through the ventilation system shall be included. The simulation of the

component equipment shall include operation at part-load as well as fullload conditions. Manufacturers' data shall be used where available and

all thermal performance characteristics of the energy-significant com- ponents as well as thermal characteristics of the building shall be given

in the report specified in 11.0.2.

11.0.5.3 The particular computer program or calculation procedure that

is used to estimate annual energy consumption shall be reviewed and

evaluated by the registered professional engineer or architect referenced

in 11.0.2. An analysis procedure which deviates from the criteria of

11.0.5.1 and/or 11,0.5.2 shall be allowed provided that it is approved

by the organization using this document.

COMMENTARY

The intent of Chapter 11 is to encourage the development and use

of solar or wind powered energy sources so as to conserve extracted

energy sources and reduce pollution. For example, assume a design

that meets the criteria of Chapters 1 through 9 and that has an annual

consumption of energy from mineral sources of 100 units. The designer

can elect to use the criteria of Chapter 11 instead of Chapters 1 through

9 and design his building to supply, say, 50 units of the energy requirement from solar energy sources. Using the formula in Figure 11-1, block

#6, he will then be permitted to design his building and service systems

to consume a total of 125 units of energy annually with 75 coming from

mineral fuel and 50 units coming from solar energy. The net saving will

be 25 units of mineral fuel and the building will be allowed a bonus

of 25 units of energy over and above the reference energy budget of

100 units.

90
The rationale for Chapter 11 and the related definition of solar

energy sources is as follows:

1) All forms of extracted energy sources commonly in use today are in short supply, will apparently remain so for the near future, and have finite limits of economic

recovery and ultimate depletion,

2) The AEC has stated that nuclear electrical power generation cannot reasonably be expected to carry a major

fraction of the electric energy load until after the turn

of the century.

3) Limitations on the total quantity of thermally generated

energy as we know it today will ultimately be determined

by the effects of various forms of pollution, including

thermal pollution. The effects of thermal and other

forms of pollution are already measurably significant,

4) Conserving energy is an essential element of the Federal

Government's goal to achieve energy self-sufficiency.

It follows that the Nation's finite energy sources and particularly

those in short supply should be conserved and used in the most efficient

manner available, and that extra incentives are neither needed nor

should be used to stimulate the exploitation of energy sources which add

pollution to the air or waterways.

91
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CONVERSION FACTORS TO METRIC (S.I.) UNITS

Physical

Quantity Symbol To convert from to

Length X inch

footmeter

raster

Area inch„

footm2

m3

Volume mcho

foot

m3

m

Temperature Fahrenheit Celsius

Temperature

difference Fahrenheit Kelvin

Pressure inch Kg (60 F) Pa

Mass Ibm

2 kg

2 Mass/unit area M Ibm/ft kg/m

Moisture content

rate -IT- / JZ^^2 1 Ibm/ ft week kg/m s Density P Ibm/ft^ kg/m-^

Thermal

2 conductivity k Btu/hr ft2(F/3.nch) W/mK

U- value U Btu/hr ft F W/m K

Thermal

resistance R

2 F/Btu/hr ft ) 2

Y.I {Wxa. )

r.T / m - neat r iow q/A w/m 134-11 /Vi-»" jt)tu/nr It

Heat flow Btu/hr W

Heat flow ton (of refrigeration W

Water vapor:

--permeability grain

0 II, kg/Pa.s

.

(perm-inch) —permeance

(perm)

hr ft^(in.Hg/in.)

gram

•1

Illumination

Flow

Flow

Wind velocity

Wind velocity

Pressure

Pressure

Cooling efficiency

Cooling efficiency

hr ft (in.Hg)

foot candle

gpm

cfm

mph

mph

Ibf/ft

psi (gage)

Btu/hr kW

Btuh/watt

Multiply by

-2 "X ID

2.54 /

3.048 10"

6.4516" X 10

9.290 X 10"^

1.639 X 10"^

2.832 X

10"

t^ = (tp- 32)/l

K = (At )/1.8

3.377 X 10

4.536 X 10"

4.882

8.073 X

10"

1.602 X 10

1.442 X

10'

5.678

1.761. X 10

3.155

2.931 X 10

-1

1

3.517 X 10'

1.459 X 10

-12

kg/Pa. s.m 5.745 x 10

Im/m

m^/s

m^/s

knots

m/s

Pa

Pa (gage)

-11

1.076 X --5

6.309 X

4.719 X

8.696 X 10-1

4.470 X 10-1

4.788 X loi

6.895 X 103

2.931 X 10--^

2.931 X 10-1

* Exact value: others are rounded to fourth place.

93
PROCEDURE FOR DETERMINING ECONOMIC EFFICIENCY

In order to avoid the possibility that any requirement of these criteria

might be counterproductive in an economic efficiency sense, it may become

necessary to determine whether a requirement is economically efficient.

To determine economic efficiency, the present worth of life-cycle energy

savings must be compared to the present worth of the extra life-cycle

costs incurred to achieve the energy savings. This section describes one acceptable method for calculating the present worth of energy savings and

extra costs, and it specifies a relationship between these two magnitudes

in order for economic efficiency to be determined.

For the purpose of these calculations, the building life (L) and the real

annual discount rate (D) must be assumed. The life-cycle energy savings,

resulting from the use of a required subsystem rather than a specific

alternative, consist of the estimated yearly difference in electrical and

fossil fuel consumption valued at present prices, which grow, in real terms,

at an annual rate of P. The extra life-cycle costs consist of additional

initial costs, additional maintenance operations, and replacement costs

through the life of the building. Real discount rates and real rates of

fuel price increases (i.e., rates of change apart from general price increases) are used to eliminate the need to estimate the rate of general inflation.

A given requirement in the document should be considered economically

efficient if the present worth of energy savings (B) is greater than the

present worth of the extra costs (C) . A requirement should be considered

economically inefficient if the present worth of energy savings (B) is

less than the present worth of the extra costs (C) . The calculation of

B and C is described as follows:

B

1 + P

D - P

S (la)

B L S D = P (lb)

where

S = the annual value of energy saving by incorporating a subsystem

or component required in the document rather than using a specific alternative.

S = Pi "l ^ P2 ^2' etc

where

p^ = the present unit price of fuel 1, and s^ = the number of

units of fuel 1 saved annually.

94
Simply stated, B Is equivalent to the present value of a stream of dollar

energy savings over L years which grow at the real rate of fuel price

increase, P, while being discounted to present value at the real discount

rate, D.

C = I +

where

1 -

(1 + D)L

D

(M + 0) + E y=l (1 +

R^

D)y (2)

D

P

I

L

M

0

real annual discount rate in decimal form.

annual rate of change in the real price of energy in decimal form.

extra initial cost incurred by incoporating a subsystem or component required by these criteria rather than using a specific alternative.

building life in years.

extra annual maintenance cost at present prices,

extra annual operations cost at present prices,

extra replacement costs in year y at present prices.

I, M, 0 and Ry may be negative. A negative value indicates that the

particular cost component of the required subsystem is lower than that

for the alternative being considered. If this is the case, the negative

sign should be retained in the computation.

In selecting specific values for D and L, lower values of L and higher

values of D will reduce B, thereby increasing the chance that the requirement

will appear to be economically inefficient. It is recommended that a building

life of no less than 30 years be used (12 years for mobile homes) and a discount rate of no more than .08 be used.

As increasingly costly energy sources are utilized, e.g.. North Sea and

North Slope oil rather than Oklahoma oil, the real price of energy can be

expected to rise during the life of the building (barring an innovation

such as the commercial generation of electricity by fusion at favorable

cost) . Therefore, it appears overly conservative to say that P equals

zero. As an attempt to capture the effect of rising real energy prices,

it is suggested that P be assumed to equal .01. This assumption means

that the nominal price of energy is expected to rise annually at a rate one percent greater than the general level of prices over the appropriate

lifetime.

95

1
NEW INFORMATION NEEDED FOR ENERGY CONSERVATION CRITERIA

ENERGY ANALYSIS DATA

The amoimt of energy consumed by building service systems is strongly

affected by the dynamic interplay of structure heat transfer characteristics and mechanical systems for heating and cooling, both of which are usually changing vith respect to time depending upon the outdoor veather

conditions and the use patterns of the building spaces such as lighting,

energy consuming equipment and occupancy.

Even with similar mechanical systems in similar types of building in the

same general locality, the energy consumption between buildings may differ

considerably depending upon the design of the central system and the

specific types of system components used.

Accurate evaluation of building energy constmiption, therefore, requires

detailed mathematical simulation of the system dynamics. Such a simulation technique has been illustrated in a document entitled, "Proposed

Procedures for Simulating the Performance of Components and Systems for

Energy Calculations", published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Although the methodology to perform dynamic simulation analysis is well

defined, the validity of such calculation is limited by the lack of

adequate technical information such as the following:

Part-Load Efficiency Data — Most of the HVAC equipment manufacturers publish efficiency data for major energy consuming components in terms of

output capacity and input power requirement at a specified design point

so that consulting engineers can select equipment to meet the heating

and cooling load of the building under steady state design conditions.

The efficiencies of components are commonly available only at a specific

design point, often 100 percent of design rated load, which seldom occurs during the course of building operation throughout the year. During most

of the year the equipment operates under part load conditions. Yet the

energy efficiency data for the part load condition are seldom available

from the manufacturer. In some cases such data are not easy to obtain

and may require considerable one-time expenditure. In order for energy

analysis to become an effective adjimct of building design, however,

part load efficiency data is essential.

Control Characteristics -— The dynamic response of a heating and cooling

system with respect to changing requirements in the space is influenced

by the manner in which the system and its equipment are controlled. If

the control is out of phase with the space heating and cooling needs.

96
much of the energy used to heat and cool the space will be wasted. This

phenomena is especially acute for the terminal reheat system and double

duct system whereby the primary energy is used to simultaneously heat

and cool the supply fluid to attain the desirable condition. The parameters that describe the performance of the control fimction are usually

expressed in such terminology as throttling range, time constant, transfer

function and LaPlace transform, details of which are found in most control

textbooks. Availability of this type of information for different types

of controls would make it possible to estimate the energy consumption of

system components as reflected in the drooping of the modulating control

or the cycle frequency, percent-on time and anticipation characteristics

of the on-off controls. However, very little information has been made

available by the manufacturers as to these parameters, nor are comprehensive algorithms available to take these factors into account for the

energy analysis.

Air Distribution To Multiple Zones From Central Fan-Plants — The amount

of chilled or heated air to be delivered to the various zones from a central fan plant is in many instances very much different from that

predicted by zone heat balance equations. Present engineering practice

for air distribution design is aimed at the sizing of the air duct, and

not suitable for evaluating the air delivery performance under actual

operating conditions. Moreover, a large amoimt of fan power is wasted

by overpressurizing supply air and subsequent throttling of it through

dampers. More comprehensive and accurate methodology for designing and

evaluating the air distribution system, such as that based upon network

analysis, is available and its use should be encouraged.

Standard Weather Data For The Energy Analysis — Weather data required for

the energy analysis is not the same as the steady state design weather

data used for the selection of heating and cooling equipment and system

design. The design weather data are basically specified as preventive

measures so that occupants can be protected from the results of inadequate

capacity of heating and cooling equipment. Such weather design criteria

are not suitable for the dynamic evaluation of energy consumption by the

equipment, since extreme weather conditions seldom prevail during the

year. The weather data needed for energy analysis must satisfy the

following requirements:

. Must contain coincidental values of temperature, humidity, wind data

and solar radiation data including percent of sky cover by clouds.

Must be conducive to dynamic analysis of building thermal performance

and system responses,

, Must be readily obtainable and usable for each locality.

Must be consistent.

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Engineering Data For Nonconventional Systems — Design and performance

analyses data are needed for nonconventional systems, such as solar and/

or wind power utilization systems, engine driven heat pumps, and heatoperated refrigeration cycles (Rankine, absorption, adsorption and fuelcell).

Simplified And Reliable Energy Calculation Procedures — Although the energy

calculation methods based upon the dynamic simulation of buildings and

building service systems fulfill a need, they require considerable effort

and a comprehensive computer program which may not be warranted in many

applications of small or simple buildings. Simple energy estimate methods

and versatility for evaluating different mechanical systems or innovative

designs are necessary. What is needed is an energy analysis procedure more

comprehensive than the degree day method yet less difficult to use than dynamic

analysis. One such attempt was made recently at the National Bureau of

Standards to estimate heating and cooling load(l). Approaches similar to

this effort need to be further developed so that the energy consumption

of less complicated buildings may be determined by a simple arithmetic

manipiilation of climatic factors, energy usage patterns and indoor con- ditions with respect to energy response factors, which will be predetermined for several typical buildings by the detailed dynamic analyses,

TESTING PROCEDURES

Most of the testing procedures published today for the HVAC equipment are for the rating or safety labeling/listing of equipment under specified

design conditions. Due to standby losses (standing pilots, stack losses,

compressor crankcase heaters, circiilating pumps, etc.) energy converting

equipment may operate with higher efficiency under the design test con- dition, than the part load conditions typical of day by day operation.

In addition, conventional testing procedures are usually under steady

loading conditions whereas the actual load is usually fluctuating. For

the purpose of energy-based evaluation of building service systems and

equipment, new testing procedures must be developed for evaluating

efficiency performance under realistic operating conditions. General

requirements for energy based testing may be stated as follows:

1. For the purpose of evaluating energy utilization efficiency,

equipment shall be subjected to standardized, non-steady load

conditions which represent the changing climatic and internal

building load patterns common to the building.

(l) Kusuda, T., Tsuchiya, T. , Powell, F.J., "Prediction of Room

Temperature by Using Equivalent Thermal Mass Response Factors", Proceedings for the 5th Symposium on Temperature, National Bureau of

Standards, Wash., D. C. 1971.

98
2 Accurate instriimentation for determining integrated energy consijmption as well as the peak power demand shoiild be used.

3. Methodology to translate the test results to actual operating

condition through mathematical simulation must be prescribed.

INFILTRATION

One of the greatest causes of building energy waste is due to unwanted

air leakage, which is usually affected by the way the buildings are constructed and by the outdoor weather conditions, particularly the temperature and wind. Yet the present technology for estimating the heat

gain and heat loss due to infiltration is relatively weak as compared to

other modes of heat transfer such as conduction and solar radiation.

Methods of testing and evaluating building air infiltration under field

conditions are presently available, but such methods need to be further

developed and reduced to consensus standard procedures.

99 *U.S. GOVERNMENT PRINTING OFFICE: 1976 210-801/195 1-3

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