January 1, 1975

V

interim performance criteria

for solar heating

and combined

heating/cooiing

systems and dwellings

Prepared for the U.S. Department of Housing and Urban Development by

the National Bureau of Standards, U.S. Department of Commerce,

Washington, D.C. 20234
U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1975

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Stock Number 0324-01043

Price: $1.90
FOREWORD

This interim perforaance criteria (IPC) document will be used for the design, development,

technical evaluation and procurement of the solar heating and cooling systems and the

dwellings to be used in the solar heating and cooling demonstration program authorized by

Public Law 93-409, the "Solar Heating and Cooling Demonstration Act of 1974."

These interim criteria are related primarily to technical performance and do not directly

address economic considerations, energy conservation or the selection of sites. These

considerations are dealt with separately in the demonstration program.

The Department of Housing and Urban Development (HUD) and the National Bureau of Standards

(NBS) are indebted to the many organizations. Government agencies, consultants, and individual

professionals who have contributed to the preparation of this document.
SI CONVERSION UNITS

In view of the present accepted practice in this country for building technology, common

U.S. units of measurement have been used throughout this document. In recognition of the

position of the United States as a signatory to the General Conference on Weights and

Measures, which gave official status to the metric SI system of units in 1960, assistance

is given to the reader interested in making use of the coherent system of SI units by

giving conversion factors applicable to U.S. units used in this document.

Length

1 in = 0.0254* meter

1 ft = 0.3048* meter

Area

1 in^ = 6.4516* x lO"'^ meter^

2 2 1 ft = 0.09290 meter

Volume

3 -5 3 1 in = 1.638 X 10 meter

-3 3 1 gal (U.S. liquid) = 3.785 x 10 meter

-3 3 1 liter = 1.000* x 10 meter

Mass

-2

1 ounce-mass (avoirdupois) = 2.83'4 x 10 kilogram

1 pound-mass (avoirdupois) = 0.4535 kilogram

Pressure or Stress (Force/Area)

3 1 inch of mercury (60°F) = 3.376 x 10 pascal

2 3 1 pound-force/inch (psi) = 6.894 x 10 pascal

Energy

1 foot-pound-force (ft-lbf) = 1.355 joule

3 1 Btu (International Table) = 1.055 x 10 joule

Power

1 watt = 1.000* X 10^ erg/second

1 Btu/hr = 0.2930 watt

Temperature

"C = 5/9 (Temperature - 32)

*Exactly

JUL
INTRODUCTION

Background

Public Law 93-409, the Solar Heating and Cooling Demonstration Act of 1974, provides for

"the demonstration within a three-year period of the practical use of solar heating technology, and . , . the development and demonstration within a five-year period of the practical

use of combined heating and cooling technology." Under the provisions of the Act, the

Department of Housing and Urban Development (HUD) has utilized the services of the National

Bureau of Standards (NBS) to develop this document containing interim performance criteria

for the design and evaluation^ of solar heating and cooling systems to be demonstrated by

HUD in residential construction.

Objectives

These interim criteria have the following objectives:

1. To provide designers, manufacturers and evaluators with the technical performance

criteria that will be used for the solar heating and cooling demonstration program.

2. To establish technical performance levels that will be used for the evaluation

and procurement of dwellings, systems, subsystems, components and elements for the

the solar heating and cooling demonstration program.

3. To provide a basis for the development of more definitive performance criteria

at a later date.

Scope

The interim performance criteria given for hardware related items such as heating systems,

combined heating and cooling systems and their various subsystems, components and elements

are intended to

:

1. establish minimum levels for health and safety that are consistent with those

given in the HUD Minimum Property Standards (MPS) for single family and multifamily housing and the ANSI A119.1 Standard for Mobile Homes .

2. ensure that the proposed heating, combined heating and cooling, and domestic hot

water systems are capable of providing minimum levels of performance consistent

with those given in the MPS,

3. verify that proposed systems, subsystems, components and elements are capable

of providing their design performance levels, and

4. ascertain that the systems, subsystems, components, and elements are durable,

reliable, readily maintainable and generally constructed in accordance with

good engineering practice.

For conventional systems, subsystems, components and elements used in the solar demonstration

program, compliance with the requirements of the MPS or ANSI A119.1 is deemed evidence that

the systems, subsystems, components and elements are durable, reliable, readily maintainable

and constructed in accordance with good engineering practice. Nonconventional systems,

subsystems, components and elements which are not discussed in the MPS or other applicable

codes and standards will be evaluated by means of these interim performance criteria to ascertain that they are reasonably reliable, durable, maintainable and capable of providing

their rated output.
The criteria given in this document for the dwellings, in which the solar energy systems

will be used, and their sites are supplementary to the provisions of the HUD MPS for single

family and multifamily housing, and the ANSI A119.1 Standard for -Mobile Homes in the case

of mobile homes. These supplementary criteria are 'intended to deal with the special

needs of housing designed for solar energy systems.

The interim performance criteria are intended to be flexible in order to allow freedom of

design and encourage innovation in keeping with the intent of Public Law 93-409.

Organization and Format

This interim document is organized on the basis of performance criteria for the complete

building heating and cooling system. Performance criteria that are uniquely applicable

to individual subassemblies of the system follow the general system requirements in each

performance area. Since it is recognized that subassemblies (such as the collectors and

storage containers) may be manufactured independently, indexing of the specific performance

requirements that are applicable to the various subassemblies of the to-tal system is

provided.

All performance statement entries are presented in the Requirement, Criterion, Evaluation

and Commentary format. The Requirement is a qualitative statement giving the user need or expectation for the item being addressed. It is a general statement of what the assembly

shall be able to do. The Criterion is generally a quantitative statement giving the level

of performance required to meet the user need or expectation for the item being addressed.

The one or more criteria associated with each requirement state the considerations which

are necessary to meet the requirement. Due to limitations in the state-of-the-art, a quantitative statement is not always contained in each criterion. In other criteria, quantitative statements have been intentionally omitted where these values will be provided by the

designer. Evaluation sets forth the methods of test and /or other information upon which an evaluative judgment of compliance with a criterion will be based. It states the standards,

inspection methods, analyses, review procedures, historical documentation, and/or test methods

which may be used in evaluating whether or not the system and its subassemblies as designed

comply with the criterion. It is expected, in many cases, that the review of documentation

of in-use performance, or engineering analysis, will be used as evaluative tools in lieu of

testing. Commentary provides background for the reader and presents the rationale behind the

selection of specific data presented in the Requirement, Criterion or Evaluation. The Commentary is intended for informational purposes, and is therefore not mandatory.

The document is divided into two parts. The first part, Systems and Components (Chapters

1 through 6) deals with interim performance criteria for heating, cooling, and domestic hot

water systems and their subassemblies. The second part. Dwellings and Sites , (Chapters 7 through 13) presents performance criteria dealing with the interactions between the solar

energy system and its surrounding environment, the dwelling and site. These performance

criteria provide for integrating the dwelling and site with the system and its components

without seriously degrading the environment or impairing the normal function of the dwelling

and its components.

Both parts of the document are organized on the basis of the first six performance attributes

listed below. An additional attribute, Visual Characteristics, is considered under

Dwellings and Sites .

1. Functional performance statements are used to evaluate the ability of systems

and their subassemblies to operate and provide their rated output. The ability

of the solar heating system to maintain the dwelling at a specified temperature

under a given set of outdoor conditions is an example of a functional consideration.
2. Mechanical performance statements treat the mechanical design and performance of

the solar energy systems and their subassemblies. Factors such as the ability of

the system to withstand normal design service conditions, e.g., pressure and

temperature, are considered under this category.

3. Structural performance statements deal with the ability of' systems and subassemblies

to maintain their structural integrity under in-service and extreme conditions.

Factors such as wind, snow and seismic loads are considered under this category.

4. Safety deals with the mitigation of hazards that could result in property damage

or injury and death. Hazards such as those due to fragile, toxic and/or flammable

materials are considered under this category.

5. Purability/Reliability relates to the ability of systems and their subassemblies

to perform designed functions for a specified interval under actual use conditions.

Corrosion and thermal degradation are typical durability/reliability related items.

6. Maintainability deals with the e^se with which systems and their subassemblies can

be maintained in good operating condition for extended periods of time. Routine

scheduled maintenance, corrective maintenance, replacements and repairs are considered under this category. Accessibility is an important maintainability consideration.

7. Visual Characteristics deals with the dwellings, the solar heating and cooling systems,

and their various subassemblies from an architectural point of view. For example,

in addition to a solar collector subsystem being compatible with the dwelli-ng on which it is installed, the entire building should be compatible with the

characteristics of the neighborhood where it is located.

The various systems and subsystems treated in the document are as follows

:

The heating (H) system is the complete assembly of subsystems and components

necessary to convert solar energy into thermal energy and use this energy in

combination with auxiliary energy, where required, for heating purposes.

The combined heating and cooling (HC) system is the complete assembly of subsystems

and components necessary to convert solar energy into thermal energy and use this

energy in combination with auxiliary energy, where required, for heating and

cooling purposes. (Where cooling is included, nocturnal radiation, evaporative cooling and/or other means may be used in combination with, or in lieu of, heat actuated

cooling.

)

The domestic hot water (DHW) system/subsystem is the complete assembly of subsystems

and components necessary to convert solar energy into thermal energy and use this energy

in combination with auxiliary energy, where required, to provide hot water in the

building. It may either be integrated directly into the H or HC systems or be com- pletely separate from them. The term "subsystem" applies when the DHW system is

integrated into the H or HC systems.

The energy transport subsystem includes those portions of the H, HC or DHW systems

which transport energy throughout the systems . Heat transfer from the collector to the point of use is accomplished through the energy transport subsystem.
The control subsystem comprises all of the devices and their electrical, pneumatic or hydraulic auxiliaries used to regulate the processes of collecting, transporting,

storing, and utilizing energy in response to the thermal, safety, and health requirements of the building occupants.

The auxiliary energy subsystem utilizes conventional energy sources both to supplement

the output provided by the solar energy systems as required by the design conditions,

and to provide full energy backup requirements during periods when the solar H, HC or DHW systems are inoperable.

The collector subsystem serves the primary function of absorbing solar radiation,

converting it into useful thermal energy, and transferring the thermal energy to

a heat transfer fluid.

The storage subsystem serves the primary function of storing thermal energy so that

it can be used when required. Specific designs may utilize hot and/or cold storage.

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vi
contents

SYSTEMS AND COMPONENTS

1. FUNCTION

1.1 H and HC system performance 1 1.2 DHW system/subsystem performance 3 1.3 Collector performance 4 1.4 Thermal storage performance 5 1.5 Habitability of occupied spaces 5 1.6 Energy transport efficiency 6 1.7 Control 6 1.8 Auxiliary energy 7

2. MECHANICAL

2.1 System design conditions 11 2.2 Mechanical stresses 13

2.3 Leakage prevention 15

2.4 Collector adjustments 16

2.5 Subsystem isolation.. 16 2.6 Heat transfer fluid quality 16

2.7 Piping supports 18

2.8 Excessive pressure and temperature protection is

3 . STRUCTURAL

3.1 Structural design basis 21

3.2- Failure loads and load capacity 23 3.3 Damage control 28

3.4 Cyclic loads 28

3.5 Cutting of structural elements 29 3.6 Creep and residual deflection 30
3.7 Hall resistance 30

3.8 Constraint loads 31

3.9 Ponding conditions 34

4 . SAFETY

4.1 Plumbing and electrical installation .37

4.2 Fail-safe controls 37 4.3 Fire safety 38

4.4 Toxic and flammable fluids 39 4.5 Safety under emergency conditions 40

4.6 Protection of potable water and circulated air 40

4.7 Excessive surface temperatures 42

5. DURABILITY/RELIABILITY

5.1 Effects of external environment 45

5.2 Temperature and pressure resistance , 47 5.3 Chemical compatibility of components 49

5.4 Components involving moving parts 51 Appendix 52

6. MAINTAINABILITY

6.1 Accessibility for maintenance and servicing 69

6-2 Installation, operation and maintenance manual 70

6.3 Repair and service personnel 71

DWELLINGS AND SITES

7. FUNCTION

7.1 Design 73

7.2 Adequate space 74 7.3 Functioning of dwelling and site.. 76

8. MECHANICAL

8.1 Interference with mechanical operation 79

8.2 Mechanical and electrical functioning of dwelling and site 80

8.3 Mechanical and electrical functioning of connections 80

9 . STRUCTURAL

9.1 Structural integrity of H, HC and DHW systems 83

9.2 Structural integrity "of dwelling 83

9.3 Structural connections 84

\jaJJ.
10 . SAFETY

10.1 Safety of dwelling and site 85

11. DURABILITY/RELIABILITY

11.1 Durability and reliability of H, HC and HHW systems 87

11.2 Durability and reliability of dwelling and site., 87

11.3 Durability and reliability of connections 88

12 . MAINTAINABILITY

12.1 Maintainability of H, HC and DHW systems 89

12.2 Maintainability of dwelling and site 90

12.3 Connections 90

13. VISUAL CHARACTERISTICS

13.1 Visual characteristics of dwelling and site ^ 91

GLOSSARY 92

INDEX 98

systems

and

components

CHAPTER ONE - FUNCTION

systems and components

1.1 Requirement H and HC system performance . The heating (H) and combined heating and

cooling (HC) systems shall be capable of collecting and converting solar

energy into thermal energy. The thermal energy shall be used to meet the

total energy needs for space heating and cooling of residential dwellings

in combination with storage and auxiliary energy, as required. Methods

of cooling such as nocturnal heat radiation, evaporation or heat actuated

air conditioning may be used, where appropriate.

1.1.1 Criterion Heating design temperatures . The heating system shall be designed to maintain the indoor temperature at 70°F for 97 1/2 percent design winter

temperatures [1]* for the geographic area(s) in which the system is to be

installed

.

Evaluation Examination of climatic data, engineering review of drawings, specifications and calculations based upon ASHRAE analytical methods

.

Commentary It is the intent that the system be designed, fabricated, installed and

operated in accordance with good HVAC engineering practice. Generally,

the system should be capable of performing at levels not less than those

specified in the HUD Minimum Property Standards (MPS) (Single Family,

4900. It7], Multifamily, 4910. 1[8] and/or the Manual of Acceptable

Practices, 4930. 1[9]) .

The 70°F and 97 1/2 percent are residential heating design values reflecting

the consensus of industry, government, and other interested representatives

working through the ASHRAE Standards Committee to develop a standard on "Energy Conservation in New Building Design (ASHRAE Proposed Standard 90P)."

Analytical and specification methods to determine heating and cooling loads

for maintaining comfort conditions in residential dwellings are described

by ASHRAE [2] [3] [4], and others [5] [6].

1.1.2 Criterion Cooling design temperatures . The cooling system shall be designed to maintain the average indoor temperature at 78°F dry bulb for outside

2 1/2 percent summer design dry bulb temperatures [1] for the geographic

area(s) in which the system is to be installed. The design shall include

•the methods of heat rejection if required for equipment operation.

Evaluation Examination of climatic data, engineering review of plans, specifications

and calculations based upon ASHRAE analytical methods.

Commentary The 78''F and the 2 1/2 percent are residential design cooling values

reflecting the consensus of industry, government, and other interested

representatives working through the ASHRAE Standards Committee to develop

a standard on "Energy Conservation in New Building Design (ASHRAE

Proposed Standard 90P)."

Typical procedures for determining cooling loads have been developed by

ASHRAE [2] [3] [4], and others [5] [6].

*Numbers in [ ] represent references given at the end of each chapter

.
CHAPTER ONE - FUNCTION

systems and components

1.1.3 Criterion Relative humidity and water vapor pressure . The operation of the H or

HC system shall not cause the water vapor pressure in the dwelling

occupied spaces to exceed 14mm Hg . Additionally, during heating, the

operation of the H or HC system shall not cause the indoor relative

humidity to exceed the appropriate values given in Figure 4 of Chapter

18 of the 1972 ASHRAE Handbook of Fundamentals [1]

.

Evaluation Examination of climatic data, engineering review of drawings, specifications and calculations.

-. - Commentary The MPS do not provide for the control of dwelling water vapor pressure

; and relative humidity. The water vapor pressure specified (14.0mm of Hg.)

is the upper limit for comfort conditions in ASHRAE Standard 55-74,

"Thermal Environmental Conditions for Human Occupancy" [10].

Typical design procedures to gain acceptable water vapor pressure and

relative humidity levels have been developed by ASHRAE [2] [3]

.

1.1.4 Criterion Solar contribution . The average yearly contribution of solar energy

to the operation of the H or HC systems shall be specified in the design

and shall result in a reduction in the average annual consumption of

conventional energy for the dwelling heating or cooling.

Evaluation Engineering review of analytical methods, drawings, test data and

calculations. An analytical model including the building heating

and cooling loads, component performance and the climatic conditions shall be utilized to predict the percentage of average monthly

and yearly total energy requirements to be provided by solar energy,

operating energy, and auxiliary energy. In certain cases, experimen-

. tal verification of system performance may be required. Theoretical

determination of system performance generally requires empirical data

defining the subsystem performance characteristics.

Commentary Some examples of analytical methods and data presentation are shown

in references [11] [12] [13] [14] [15] [16]. Sources of insolation

data and data reduction methods are described in references [17] [18]

[19] [20].

1.1.5 Criterion Operational Impairment . The functional capability of the H or HC

system shall not be impaired to a greater extent than conventional

systems when system repairs or modifications are being made.

Evaluation Engineering review of specifications and drawings.

Commentary This criterion is intended to ensure that the shutdown for repair or modification of solar powered portions (e.g., the collector subsystem)

of the H or HC system will not impair the function of the H or HC

system for periods of time longer than those expected for conventional

heating or cooling equipment

.

The duplication of components such as blowers, controls and pumps is

dependent upon the degree of integration of the auxiliary energy subsystem and the availability of replacement parts.

2
CHAPTER ONE - FUNCTION

systems and components

1.2 Requirement DHW system/subsystem performance . The domestic hot water (DHW) system/

subsystem shall be capable of collecting and converting radiant solar

energy into thermal energy which shall be used 'in combination with

storage, where provided, and auxiliary energy to supply an adequate

amount of potable hot water at an acceptable temperature to meet the

needs of the user.

1.2.1 Criterion Water design temperature . The DHW system/subsystem shall meet the

requirements established for draw and recovery specified in the MPS

(Tables 6-15.2 and 6-15.3) [7] [8] at a tap temperature of 140°F.

Evaluation Engineering review of plans, specifications and calculations.

Commentary The amount of hot water required will vary with cliihate, dwelling type

and number of occupants. Average family requirements of 50 gal. per

day for domestic use and 75 gal. per day if an automatic cycle washer

is used are common practice for estimating fuel costs for heating

water[21]. Domestic hot water temperatures provided can vary from 105°F

to 160°F but an average value 140°F should be used for calculating the

energy requirements.

Typical procedures for determining domestic hot water requirements have

been developed by ASHRAE[21]

.

1.2.2 Criterion Storage design capacity . The DHW storage capacity shall not be less

than the volume specified in the MPS [7] [8].

Evaluation Review of drawings, specifications and calculations.

Commentary Stratification in solar heated water containers may be different from that

in conventional hot water storage tanks and should be considered in the

design. High utilization of the solar collector is related to the

storage component characteristics. Typical methods for calculating

domestic hot water storage requirements are given by ASHRAE[21]

.

1.2.3 Criterion Solar contribution . The average yearly contribution of solar energy

to the operation of the DHW system/ subsystem shall be specified in the

design and shall result in a reduction in the average annual consumption

of conventional energy for domestic hot water heating.

Evaluation Engineering review and analysis of drawings, test data and calculations.

An analytical model including at least the source water temperature, hot

water requirements, DHW component performance, and the climatic conditions shall be utilized to predict the percentage of average monthly

and yearly total energy requirements to be provided by solar energy, operating energy, and auxiliary energy from conventional energy sources.

Experimental verification of system performance shall be performed,

where required. Theoretical determination of system performance generally requires empirical data defining the subassembly performance

characteristics

.

Commentary Examples of analytical methods and dkta presentation are shown in the

references [12] [13] [14] [21] [22] [23] [39].

3
CHAPTER ONE - FUNCTION

systems and components

1.2. A Criterion Operational Impairment . The functional capability of the DHW system/

subsystem shall not be impaired to a greater extent than conventional

systems when system repairs or modifications are being made.

Evaluation Engineering review of specifications and drawings.

Commentary This criterion is intended to ensure that the shutdown for repair or modification of solar powered portions (e.g., the collector subsystem)

of the DHW system/subsystem will not impair the function of the DHW

system/subsystem for periods of time longer than those expected for

conventional hot water equipment.

The duplication of components such as heat exchangers, controls and

pumps is dependent upon the degree of integration of the auxiliary

energy subsystem and the availability of replacement parts

.

1.3 Requirement Collector performance . The solar collector shall absorb and convert

incident solar energy into useful thermal energy. The collector shall

be capable of dissipating' thermal energy, where this function is

included in the design.

1.3.1 Criterion Collector efficiency . The collector subsystem (including reflectors

where applicable) shall be capable of absorbing and converting

incident solar energy into useful thermal energy at its designed

efficiency under operating conditions. For applications employing

nocturnal radiation, the collector shall dissipate thermal energy

at the design rate under design operating conditions.

Evaluation Engineering evaluation of drawings, analytical calculations and/or

test data.

An analytical model, when used, shall include radiant, convectlve

and conductive heat transfer, where appropriate.

The design collector thermal efficiency may be experimentally verified utilizing a full-scale test panel or a model test panel of

sufficient size to have equivalent full-scale thermal characteristics.

It is intended that testing be performed only if performance data

for the particular collector or one with similar materials and/or

configuration is not available. Because of the influence of solar

radiation characteristics, climatic conditions and system operating

requirements on performance, experimental evaluations shall include

heat transfer media flow rates and temperatures consistent with the

geographic region and system conditions.

Commentary Some examples of analytical methods and data presentation are shown

in the references [1] [12] [13] [14] [15] [16] [24] [25] [26] [27]

[36] [37]. Descriptions of collector test techniques and representative test data are presented in references [13] [28] [29] [30] [31] to illustrate methodologies considered to be state-of-the-art . The use of material, fluid and insolation property data available in the

open Ifterature is encouraged.

4
CHAPTER ONE - FUNCTION

systems and components

1.4 Requirement . Thermal storage performance . When included in the design, the storage

subsystem shall be capable of providing its rated output under design

loads

.

1.4.1 Criterion Storage capacity and rate . The storage subsystem shall provide

sufficient heat transfer rates and thermal energy capacity to absorb

and store energy at the maximum design collection rate and, when fully

charged, supply energy for its design time period with no solar energy

or auxiliary energy input

.

Evaluation Engineering review of drawings, calculations and/or test data.

A thermal analysis of the storage subsystem shall be performed to determine the thermal energy storage capacity, heat losses, energy

addition rate and energy extraction rate under operating conditions.

For designs where adequate calculations are not possible these parameters shall be experimentally determined utilizing a full-scale

test specimen or a model test specimen of sufficient size to have

equivalent full-scale thermal characteristics.

Commentary Descriptions of storage techniques and representative test data

are presented in references [12] [13] [14] [16] [32] [33] [34] to illustrate

methodologies considered to be state-of-the-art. The thermal capacity

is a function of system dynamic characteristics and may be sized to include factors such as insolation level, collector area, thermal

loads, energy loss, temperature gradients, material thermophysical

properties and auxiliary energy type and amount.

1.5 Requirement Habitability of occupied spaces . The presence of the system components

shall not significantly affect the efficient operation of the H, HC or DHW systems or the habitability of the dwelling.

1.5.1 Criterion Heat or humidity transfer effects . Heat or humidity transfer from the

collector, thermal storage, piping or other elements shall not interfere

with the efficient operation of the H, HC or DHW systems or cause loss

of control of temperature, humidity or other comfort conditions.

Evaluation Engineering review of drawings, specifications, calculations and

test data. A thermal analysis including calculations of the heat

transfer and condensation rates from all storage containers, piping

and other thermally insulated components or test data on equivalent

material and configurations shall be used.

Commentary It is realized that some heat transfer from insulated piping and storage containers will occur within or under a building structure. Overheating and condensation can create adverse conditions for pumps,

motors and controls. Design considerations are discussed in several

references [2] [3] [7] [8] [9] [10] [35].

5
CHAPTER ONE - FUNCTION

systems and components

1 . 6 Requirement

1.6.1 Criterion

Evaluation

Commentary

1.7 Requirement

1.7.1 Criterion

Evaluation

Commentary

1.7.2 Criterion

Energy transport efficiency . The energy transport subsystem shall

transfer the required thermal energy between the operating subsystems

at or above the design efficiency under design full load conditions.

Thermal losses and electrical power . Thermal losses and use of electrical power in the energy transport subsystem shall not exceed the

operating design values.

Engineering review of drawings, specifications, calculations and

test data.

The losses in the distribution system influence the total system

efficiency as well as operating electrical energy required for

pumping. Variations in the thermal conductivity and specific heat

of the heat transfer medium with temperature should be considered

in the design. Design data and analytical procedures for thermal

insulation and heat transfer in building systems are available

in the literature [1] [2].

Control . The control subsystem shall provide for the safe and

efficient operation of the H, HC and DHW systems.

Installation and maintenance . The control subsystem shall include such

provision for manual bypass, adjustment, or over-ride of automatic con- trols as is required to facilitate installation, startup, shutdown and

maintenance

.

Review of drawings, specifications and operating procedures.

Provision for manual controls may be needed during installation and

start up to balance or adjust the system for proper operation. Other

manual controls may be required for tests or maintenance after the

system has been in operation or for seasonal shutdown.

Manual adjustment . If manual controlled adjustments are required

during normal operation of the H, HC and DHW system/subsystem, the

control subsystem shall insure that:

a. The safety and durability of the H, HC and DHW systems and

the dwellings in which they are installed are not compromised

by failure to perform the manual adjustments for a reasonable

period of time. The time period, as well as any contingent

environmental conditions, shall be stipulated by the designer.

b. The control subsystem is designed for reasonable dwelling

occupant convenience regardless of whether operating with

solar energy, ai;«iliary energy or a combination of these

energy sources.

6
CHAPTER ONE - FUNCTION

systems and components

Evaluation. Review of drawings, specifications and operating procedures.

Commentary These provisions are not intended to restrict appropriate seasonal shutdown manual controls.

It is desirable that solar systems' require no more operational supervision

than conventional systems. However, demonstration systems may require

various degrees of attention for periodic adjustments.

1.7.3 Criterion Inhabited space temperature . Each H and HC system shall be provided with

at least one readily adjustable automatic control for the regulation of

temperature in the living spaces. Each such control or combination of

controls or sensors shall be capable of being set to control at least

within the range from 55°F to 85°F.

Evaluation Review of drawings and specifications.

Commentary In certain multizone or multisystem applications, a priority control may

be needed to avoid simultaneous heating and cooling of a common conditioned

space. Controls presently used in conventional heating and cooling systems

are capable of responding to a 1/2°F variation from the set point. Localized controls for building heating and cooling are discussed in reference [38]

1.7.4 Criterion Hot water temperature . The DHW system/subsystem shall be provided with a manually set, automatic control that provides effective regulation of the

domestic water output temperature. The water temperature at the DHW stor- age tank shall be capable of being controlled within the range of 105°F

to 160°?.

Evaluation Review of drawings and specifications,

Commentary The MPS requires that tap temperatures in one and two family dwellings

for the elderly [7] and in all multifamily housing [8], must be below

140°F to prevent injury from scalding. The maximum temperature available

from the tap is an important safety consideration which is addressed by

most building codes and standards.

1.8 Requirement Auxiliary energy . The auxiliary energy subsystem shall be integrated

into the H, HC and DHW systems to the extent necessary to automatically

provide the designed heating, cooling and domestic hot water.

1.8.1 Criterion Design loads . The auxiliary energy subsystem shall be designed to meet the

requirements for heating, cooling and domestic hot water specified in

criteria 1.1.1, 1.1.2 and 1.2.1, respectively.

Evaluation Engineering review of plans, specifications, calculations and test methods

.

Commentary The purpose of this criterion is to back up the H, HC and DHW systems

used in the Demonstration Program with 100 percent operating capability

when energy derived from solar radiation is not available. Design heating

and cooling loads are discussed by ASHRAE [1] [2] [3] [38] and the MPS

[7] [8] [9].

7
CHAPTER ONE FUNCTION

systems and components

References

1. ASHRAE Handbook of Fundamentals - 1972 , Chap. 33, ASHRAE, New York., N.Y. (1972).*

2. ASHRAE Handbook and Products Directory, 1973 Systems , Sect. 1 and Chap. 43,

ASHRAE, New York, N.Y. (1973).*

3. ASHRAE Handbook and Products Directory, 1974 Applications , Chap. 1, ASHRAE,

New York, N.Y. (1974) .*

4 . Procedure for Determining Heating and Cooling Loads for Computerized Energy

Calculations - Algorithms for Building Heat Transfer Subroutines - Task Group

on Energy Requirements for Heating and Cooling, ASHRAE, New York, N.Y, (1971).*

5. Kusuda, T. and Powell, F.J., "Use of Modern Computer Programs to Evaluate

Dynamic Heat Transfer and Energy Use Processes in Buildings," Performance

Concept in Buildings , Vol. 1, NBS Special Publication 361, National Bureau

of Standards, Washington, D.C. (1972) . t

6. Lokmanhekim, M. and Henninger , P.H.,, "Computerized Energy Requirement Analysis

and Heating/Cooling Load Calculations of Buildings," ASHRAE Journal , Vol. 14,

pp. 25-33 (April 1972).

7. HUD Minimum Property Standards, One and Two Family Dwellings , (No. 4900.1),

U.S. Department of Housing and Urban Development, Washington, D.C. (1973,

revised 1974) . t

8. HUD Minimum Property Standards, Multifamily Housing (No. 4910.1), U.S.

Department of Housing and Urban Development, Washington, D.C. (1973).

t

9. The Manual of Acceptable Practices (No. 4930.1), U.S. Department of Housing

and Urban Development, Washington, D.C. (1973) -t

10. Thermal Environment: al Conditions for Human Uccupancy , ASHRAE Standard 55-74^

ASHRAE, New York, N.Y. (1974).*

11. Tybout, R.A. and Lof , G.O.G., "Solar House Heating", Natural Resources , Vol. 10, No. 2, p. 268 (1970).

12. Solar Heating and Cooling of Buildings - Phase 0 , National Science Foundation

Reports NSF/RA/N-74-021B , NSF/RA/N-74-022B , and NSF/RA/N-74-023B , Washington, D.C

(May, 1974).

13. Duffie, J. A. and Beckman, W.A., Solar Energy Thermal Process (Wiley - Interscience Publication, John Wiley and Sons) New York, N.Y. (1974).

14. Klein, S.A., Cooper, P.I., Beckman, W.A., and Duffie, J. A., TRNSYS : A Transient

Simulation Program , Solar Energy Laboratory, University of Wisconsin - Madison,

Madison, Wis. (December 1973, revised October 1974).

15. Low Temperature Engineering Application of Solar Energy , ASHRAE, New York,

N.Y. (1967).*

16. ASHRAE Handbook and Products Directory, 1974 Applications , Chap. 59, ASHRAE,

New York, N.Y. (1974) .*

8
CHAPTER ONE - FUNCTION

systems and components

17. Liu, B.Y.H. and Jordan, R.C., "Availability of Solar Energy for Flat-Plate Solar

Heat Collectors", Chap. I, Low Temperature Engineering Application of Solar Energy , ASHRAE, New York, N.Y. (1967).*

18. Bennett, I., "Monthly Maps of Mean Daily Insolation for the United States",

Solar Energy , Vol, 9; p. 145, Pergamon Press, Elmsford, N.Y. (1965).

19. Climatic Atlas of the United States , U.S. Department of Commerce, Washington,

D.C. (June 1968) .t

20. Climatological Data - National Summary , National Climatic Center, Asheville, N.C.

(published monthly)

.

21. ASHRAE Handbook and Products Directory , 1973 Systems. Chap. 37, ASHRAE

New York, N.Y. (1974) .*

22. Lof, G.O.G. and Close, D.J., "Operation and Design of Solar Water Heaters", Chap. VI,

Low Temperature Engineering Application of Solar Energy , ASHRAE, New York, N.Y. (1967).*

23. Chinnery, D.N.W., Solar Water Heating in South Africa , National Building Research

Institute Bulletin No. 44, Council for Scientific and Industrial Research Report

No. 248, pp. 1-79, Pretoria, South Africa. (1967)

.

24. Speyer, E., "Solar Energy Collection with Evacuated Tube", Journal of Engineering

for Power , p. 270, Transactions, American Society of Mechanical Engineers, New York,

N.Y. (1965).

25. Buchberg, H. , Lalude , O.A. and Edwards, D.K., "Performance Characteristics of

Rectangular Honeycomb Solar -Thermal Convertors", Solar Energy , Vol. 13, p. 193,

Pergamon Press, Elmsford, N.Y. (1971).

26. Klein, S.A., Duffie, J. A. and Beckman, W.A. , "Transient Considerations of Flat-Plate

Solar Collectors", Journal of Engineering for Power , pp. 1-5, Transactions, American

Society of Mechanical Engineers, New York, N.Y. (1974).

27. Ostad-Hosseini , A., Performance of a Vertical Flat Plate Solar Collector , Report No. NSF/RANN/SE/GI27976/TR72/15, University of Pennsylvania, Philadelphia, Pa. (December, 1972).

28. Hill, J.E. and Kusuda, T., Method of Testing for Rating Solar Collectors Based on Thermal Performance , NBSIR 74-635, National Bureau of Standards, Washington, D.C.

(December 1974)

.

29. Lior , N. and Saunders, A.D., Solar Collector Performance Studies , Report No. NSF/RANN/SE/GI29976/TR73/1, University of Pennsylvania, Philadelphia, Pa. (June 1974, Revised August 1974).

30. Simon, F.F., Collector Test Procedure and Experiments with the Solar Simulator , National Aeronautics and Space Administration, Lewis Research Center, Cleveland,

Ohio (November 1974). Available from University of Maryland, College Park, Md

.

9
CHAPTER ONE - FUNCTION

systems and components

31. Vernon, R.W., Collector Test Procedure and Experiments with an Outdoor Test Rig , National Aeronautics and Space Administration, Lewis Research Center, Cleveland,

Ohio (November 1974).. Available from University of Maryland, College Park, Md.

32. Kelly, G.E. and Hill, J.E., Method of Testing for Rating Solar Thermal Energy

Storage Based on Thermal Performance , NBSIR 74-634, National Bureau of Standards,

Washington, D.C. (December 1974).

33. Telkes, M. , "Storage of Solar Heating/Cooling", ASHRAE Journal , Vol. 16, p. 39,

ASHRAE, New York, N.Y. (September 1974).*

34. Ghepurniy, H. and Savage, S.B., "An Analytical and Experimental Investigation of a Laboratory Solar Pond Model", Paper No. 74-WA/Sol-3, American Society of Mechanical

Engineers, New York, N.Y. (November 1974).

35. ASHRAE Equipment Guide and Data Book - 1972 , pp. 37-71, ASHRAE, New York, N.Y. (1972)

36. Bliss, R.W. Jr., "Atmospheric Radiation Near the Surface of the Ground, A Summary

for Engineers," Solar Energy , vol. 5, pp. 103-120, Pergamon Press, Elmsford,

N.Y. (1961).

37. Duff, W.S. and Lameiro, G.F., "A Performance Comparison Method for Solar Concentrators", Paper No. 74-WA/Sol-4, American Society of Mechanical Engineers,

New York, N.Y. (November 1974).

38. ASHRAE Handbook and Products Directory - 1973 Systems , Sect. IV, ASHRAE, New York,

N.Y. (1973).*

39. Gutierrez, G., Hincapie, F., Duffie, J. A., and Beckman, W.A., "Simulation of

Forced Circulation Water Heaters; Effects of Auxiliary Energy Supply, Load Type

and Storage Capacity", Solar Energy , vol. 15, pp. 287-298, Pergamon Press,

Elmsford, N.Y. (1974) .

*Available from American Society of Heating, Refrigerating and Air-Conditioning

Engineers, Inc., 345 East 47th Street, New York, N.Y. 10017

tAvailable from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

10
CHAPTER TWO - MECHANICAL

systems and components

2.1 Requirement System design conditions . The systems for heating (H) and combined

heating and cooling (HC) and the domestic hot water (DHW) system/

subsystem shall be capable of functioning at their designed flow rates,

pressures and temperatures.

2.1.1 Criterion Equipment capabilities . Pumps, fans, or other components shall be sized

to move the heat transfer fluid through the collector, piping and/or

ducts at~ design flow rates.

Evaluation Review of drawings, specifications, historical performance, previous

test data, and design calculations. Systems or applications that do

not lend themselves to engineering analysis may require prototype tests

to demonstrate compliance.-

Commentary In order to transfer heat through the system/subsystem, a number of

different transfer approaches such as gravity circulation , combined

forced and gravity circulation, or forced circulation may be used.

2.1.2 Criterion Noise or erosion-corresion . The piping or ducts and associated fittings

shall be sized to carry the heat transfer fluid at design flow rates

without excessive noise, as defined by HUD[1] , or erosion-corrosion.

Eval,uation Review of drawings, specifications, historical performance, previous

test data and design calculations.

Commentary In order to prevent whistling noise in piping and cavitation noise

in fittings and valves, it is recognized practice to limit velocities

of transfer fluids to 8fps[2]. Lower velocities may be required depending

on the limit set by the pipe manufacturer to prevent deterioration

of their piping materials due to erosion-corrosion. It is common practice to limit flow velocities in small diameter copper tubing to 4fps when water having a pH value lower than 6.9 or softened water is

used. A velocity of 4fp6 is commonly used as the upper limit for hot water

piping with working temperatures above 150°F for copper tubing[2]. Some

equipment designs may require higher flow velocities in order to inhibit scale formation. In air ducts, the velocities normally should

not exceed recognized values, e.g., the values listed on U.L. labels.

2.1.3 Criterion Operating conditions . Collectors, space heaters, water heaters, pumps,

valves, regulating orifices, pressure regulators and similar components

shall be capable of being operated over the pressure and temperature

ranges anticipated in actual service without breakage, rupture,

binding, galling, or significant loss in pressure that could impair

their intended function.

Evaluation Review of drawings, specifications, historical performance, previous

test data and design calculations. Systems or components that do

not lend themselves to engineering analysis shall be tested at the

maximum and minimum service temperatures with anticipated fluid pressures. To show compliance with this criterion it is desirable that the

design consist of components that are covered by recognized standards,

where available, and are specified by the manufacturer to be suitable

for the pressure, temperature, and flow application.

11
CHAPTER TWO - MECHANICAL

systems and components

A list of recognized standards is given in the HUD Minimum Property

Standards [3 ] . Available codes and standards are also listed in ASHRAE

[4].

2.1.4 Criterion Fluid flow in collectors . When an array of collectors is connected

by manifolds, provision shall be incorporated in the manifolds and/or

collectors to maintain the design flow rate of the heat transfer fluid

through each collector.

Evaluation

Commentary

Review of drawings, specifications, historical performance, previous

test data, and design calculations or testing to determine that each

collector will receive its design flow rate.

Because of friction in the manifold

through collectors remote from the

This can result in ineffi^cient coll

flow regulating valves is one means Another method is the use of revers parallel arrays of collectors with

rate in the header changes. Useful

reference [5]

.

flow rates may be inadequate

pump or other fluid supply source, ector operation. The provision of

of correcting for this problem,

ed supply and return headers for

graduated header sizes as the flow

design information is given in

2.1.5 Criterion Entrapped air . When liquid heat transfer fluids are used, the system

shall provide suitabld^ means for air removal.

Evaluation Review of drawings and specifications.

Commentary Trapped air in a piping system can impede the flow of liquids through

piping, decrease pumping efficiency and otherwise reduce system

efficiency. Possible icing up of exposed fittings is an Important

consideration.

2.1.6 Criterion

Evaluation

Commentary

Thermal expansion of fluids . Adequate provisions for the thermal

expansion of heat transfer fluids that would occur over the service

temperature range shall be incorporated into the system designs.

Review of drawings, specifications and design calculations.

Water expands about 4% in volume when heated from 40°F to 200°F. Other

heat transfer fluids may have different coefficients of volume expansion.

Means should be provided in the system design to contain this additional

fluid volume without exceeding the operating pressure of the system or resulting in spillage.

2.1.7 Criterion Pressure drops. Pressure drops shall not exceed the limits specified

in the design.

Evaluation Review of calculations, and detailed plan and elevation drawing layouts.

12
CHAPTER TWO - MECHANICAL

systems and components

Commentary Since the energy requirements of pumps and fans are a function of the

system flow resistance, pressure drops should be kept as low as possible, commensurate with good design. The unnecessary use of fit-,

tings such as bends, tees, globe valves, reducers, or obstructions

to flow should be avoided by careful arrangement of piping runs.. Accepted practices for plumbing design are discussed in standard

plumbing guides [6] [7].

2.1.8 Criterion Condensate removal . Means shall be provided for adequate disposal of

condensate from cooling equipment. Provisions shall be made to assure

that condensate will overflow into a safe, appropriate drainage system.

Evaluation Review of drawings and specifications.

Commentary When the temperature of the cooling surface is at or below the dewpoint temperature of the incoming air passing over the surface, water

vapor from the incoming air will condense on the surface. The con- densate will run off the surface to low points or collection points

below the surface where it must be removed.

2.2 Requirement Mechanical stresses . Mechanical stresses that arise within the

system shall not cause damage or malfunction of the system or its

components

.

2.2.1 Criterion Vibration stress levels . Vibrations in piping, ducts, instrumentation

lines, and control devices shall be controlled to reduce stress levels

below those that could cause fatigue and subsequent component damage.

Evaluation Review of drawings, specifications, historical performance, and

previous test data for adequate piping and equipment supports.

Commentary Examples of possible vibration sources in piping are as follows:

a. Lengths of piping and connecting equipment that are resonant

with pressure pulsation frequency.

b. Vibration resulting from motors, pumps, fans, and compressors

which are not properly mounted.

c. Water hammer and quick closing valves.

d. Expansion and contraction of piping on hangers.

e. Wind pulsations on certain lengths and diameters of piping

supported by loose hangers or supports.

2.2.2 Criterion Vibration from moving parts . Pumps, fans and compressors or similar

equipment shall be balanced and/or mounted in a manner that will

avoid vibration that could cause damage or excessive noise as defined

by HUD[1]

.

13
CHAPTER TWO - MECHANICAL

systems and components

Evaluation Review of drawings and specifications. Prototype inspection and testing if deemed necessary. The equipment supporting structure shall not

have natural frequencies within + 20 percent of the operating speeds.

The equipment when mounted and placed in operation should not exceed

a self-excited vibration velocity of 0.10 inches per second when

measured with a vibration meter on the bearing caps of the machine

in the vertical, horizontal, and axial directions or measured at the

equipment mounting feet if the bearing caps are concealed [8]

.

2,2.3 Criterion Water hammer . When a liquid is used as the transfer fluid and quick

closing valves are employed in the design, the piping system shall

be able to control ,or withstand potential induced "water hammer."

Evaluation Review of drawings, specifications, and/or design calculations.

Commentary Pressure rises resulting from water hammer may damage piping and

equipment. It can be minimized by piping system design, or the use of

water hammer arresters [9] [10].

2.2.4 Criterion Vacuum relief protection .. Closed storage tanks and piping located at elevations above the system served shall be suitably protected against

collapse by pressure if subjected to a vacuum. Such components shall be

designed to withstand such pressures or have vacuum relief protection.

Evaluation Review of drawings and specifications.

Commentary Possible collapse of large diameter tanks and piping by atmospheric

pressure is an important design consideration [11 ]

.

2.2.5 Criterion Thermal changes . The system components and assemblies shall be

designed to allow for the thermal contraction and expansion that

would occur over the service temperature range.

Evaluation Review of drawings, specifications and calculations.

Commentary Piping and other components may experience changes in dimensions as

a result of temperature changes. Such changes can result in excessive

stresses within the piping, piping supports, structure, pumps, com- pressors, and solar collectors if means are not incorporated in the

piping system design to allow for the thermal movement.

2.2.6 Criterion Flexible joints . All systems employing heat transfer fluids shall be

designed to be capable o'f accommodating flexing of plumbing and fittings.

Evaluation Review of drawings and specifications.

14
CHAPTER TWO - MECHANICAL

systems and components

2.3 Requirement Leakage prevention . System assemblies containing heat transfer fluids

shall not leak to an extent greater than that specified in the design

when operated at the design conditions.

2.3.1 Criterion Pressure test: nonpotable fluids . Those portions of the H, HC and DHW

systems which contain heat transfer fluids (other than air) and are

not directly connected to the potable water supply shall not leak

when pressures of not less than 1-1/2 times their working pressure

are imposed for a minimum of 15 minutes

.

Evaluation Review of specifications and testing. The test pressure shall be

applied for a period of time necessary to inspect each joint for

leakage. The pressure gage would be observed for this period to determine that a pressure drop has not occurred.

Commentary Various building codes differ with regard to pressure tests. One

plumbing code requires hydrostatic testing at the working pressure

for water supply piping [12]. Another code requires hydrostatic

testing at the working pressure or an air pressure test of not less

than 50 psi for not less than 15 minutes [13]. A third code requires

a hydrostatic test of not less than 25 psi above the working pressure

[14]. However, plumbing codes do not give guidance concerning solar

systems which can contain liquids other than water. In these cases, hydrostatic testing of the system at 1-1/2 times the maximum is

considered to be appropriate [15 ] . "Dead-Weight" testers are frequently

used to calibrate pressure gages [16].

2.3.2 Criterion Pressure test: potable water . Those portions of the H, HC and DHW

systems that are directly connected to the potable water supply system

shall not leak when tested in accordance with the code having jurisdiction in the area where the system is used. In areas having no building code, a nationally recognized model code shall be used.

Evaluation Review of drawings and specifications.

Commentary See Commentary for 2.3.1

2.3.3 Criterion Air transport systems . Duct systems shall be designed and installed

in accordance with Section 615-4.3 of the HUD MPS[3].

Evaluation Review of plans and specifications.

15
CHAPTER TWO - MECHANICAL

systems and components

2.4 Requirement Collector adjustments . The collector subsystem shall be capable of

being located, oriented, and tilted as required by the design to capture

sufficient solar energy to meet functional requirements.

2.4.1 Criterion Orientation and tilt . The collector mount shall be capable of maintaining the design tilt and orientation.

Evaluation Review of drawings and specifications.

Commentary Collectors can either be fixed, require seasonal adjustment or be

continuously movable. Detailed information concerning orientation

and tilt is given in ASHRAE[17]. It is not the intent of this criterion

that the collector necessarily be reoriented or tilted after initial

:. installation.

2.4.2 Criterion Mutual shadowing . Collectors shall be installed so that mutual

shadowing does not 'exceed design limits.

Evaluation Review of drawings (site and system), specifications and calculations.

Commentary Data are available for calculating shading angles with respect to the time of day and year [18].

2.5 Requirement Subsystem isolation . Shutdown of the subsystems in one dwelling unit

shall not impair the distribution of energy to other dwelling units of

the building.

2.5.1 Criterion Shutdown in multifamily housing . The shutdown of the H, HC or DHW

subsystems in one dwelling unit of a multifamily housing complex shall

not interfere with the operation of the subsystems in other dwelling

units

.

Evaluation Review of drawings and specifications.

Commentary This is to permit the shutdown of equipment in an individual dwelling

unit for repairs without impairing the operation of the equipment in

other dwelling units that are connected to the same central system.

2.6 Requirement Heat transfer fluid quality . Provision shall be made to maintain the

quality of the heat transfer fluid at a level that does not impair its

heat transfer function.

16
CHAPTER TWO - MECHANICAL

systems and components

2.6.1 Criterion Liquid quality . The system shall have means to prevent contamination

by foreign substances that could impair the flow and quality of the

heat transfer fluid beyond acceptable limits.

Evaluation Review of piping drawings and specifications.

Commentary The piping in some solar collectors and heat exchangers may have small

cross sections in which blockage by dirt, scale, pieces of gasket

material, pieces of packing, or other foreign matter in the heat trans- fer fluid could occur.

2.6.2 Criterion Air quality . Duct and fan systems shall be protectee against accumulation of deposits of dust or dirt that could reduce flow and efficiency.

Evaluation Review of drawings and specifications for protection means.

Commentary Accumulation of dust on fan blades, in collector heat transfer surfaces,

"and within the ducts will increase flow resistance, and decrease system

efficiency

.

2.6.3 Criterion Fluid treatment . Suitable devices and procedures shall be provided

to assure that the chemical composition of the heat transfer fluid is

maintained at levels adequate to prevent unacceptable deposits on the

heat transfer surfaces or corrision of the surfaces with which the heat

transfer fluid comes in contact.

Evaluation Review of drawings and specifications.

Commentary Problems can develop when fluids such as "hard" water are used.

2.6.4 Criterion Freezing protection . Heat transfer liquids shall be prevented from

freezing at the lowest ambient temperatures that will be encountered

in actual use where such freezing would impair the function of the

system.

Evaluation Review of drawings and specifications.

Commentary The purpose of this criterion is to insure that rupture or other

damage to solar collectors and associated piping and equipment will

not occur from expansion of water if it freezes. The intent of this

criterion is not to restrict the designer to the use of antifreeze

solutions

.

17
CHAPTER TWO MECHANICAL

systems and components

2.7 Requirement Piping supports . Pipe hangers, pipe trenches, and other supports

shall carry the static and operational loads normally imposed wxthout impairing system function.

2.7.1 Criterion Applicable plumbing standards . Piping shall be installed in accordance

with Section 615 of the MPS (4900.1 and 4910.1) [3] and Part C of the

ANSI A119.1[19], where applicable.

Evaluation Review of drawings, calculations and specifications.

Commentary Both above-ground and underground piping and heat distribution

installations are dealt with in the HUD MPS and other references

[20] [21] [22] [23].

2 . 8 Requirement Excessive pressure and temperature protection . The piping system and

associated equipment shall be protected against rupture or leakage

from excessive pressures and temperatures.

2.8.1 Criterion Relief valves and vents . As required for protection of a particular

system design, combination temperature and pressure relief valves,

separate pressure relief valves, pressure reducing valves, and/or

' atmospheric vents shall be provided.

Evaluation Review of drawings and specifications.

Commentary This criterion is intended to prevent safety hazards resulting from

inadequate pressure and temperature protection.

18
CHAPTER TWO - MECHANICAL

systems and components

References

1. Noise Abatement and Control , HUD Circular 1390.2, U.S. Department of Housing

and Urban Development, Washington, D.C. (August 4, 1971).

2. National Standard Plumbing Code , National Association of Plumbing-HeatingCooling Contractors, Appendix B, pp. 10-11, Washington, D.C. (1973).

3. HUD Minimum Property Standards , One and Two Family Dwellings (No. 4900.1),

U.S. Department of Housing and Urban Development, Washington, D.C. (1973,

revised 1974)* and HUD Minimum Property Standards, Multifamily Housing , (No. 4910.1), U.S. Department of Housing and Urban Development, Washington,

D.C. (1973).*

4. ASHBAE Handbook and Products Directory, 1974 Applications , Chap. 60, ASHRAE,

New York, N.Y. (1974) .t

5. Ward, J.C., "Turbulent Flow in Porous Media", Journal of the Hydraulics

Division , American Society of Civil Engineers, vol. 90, No. HY5 , Part 1, pp. 1-12, New York, N.Y. (September 1964).

6. King, R.C. and Crocker, S., Piping Handbook , 5th ed . , Chap. 3, p. 130,

(McGraw-Hill Book Company, New York, N.Y., 1967).

7. Marks, L.S., Mechanical Engineers Handbook , 6th ed . , Sect. 12, p. 102

(McGraw-Hill Book Company, New York, N.Y., 1958).

8. "Vibration Isolation", Sect. 1515, Public Buildings Service Guide Specifications , PBS: 4-1515, General Services Administration, Washington, D.C. (April 1970).

9. Water Hammer Arresters , USA Standard A112,26.1, American Society of Mechanical

Engineers, New York, N.Y. (1969).

10. Dawson, F.W. and Kalinske, A.A. , Water Supply Piping for the Plumbing System , Institute of Hydraulic Research, Iowa City, Iowa, p. 50 (1942).

11. Windenburg, D.F., "Vessels under External Pressure", Mechanical Engineering . American Society of Mechanical Engineers, pp. 601-607, New York, N.Y. (January 1937) .

12. National Standard Plumbing Code , National Association of Plumbing-HeatingCooling Contractors, Chap. 15, p. 2, Washington, D.C. (1973).

13. Uniform Plumbing Code , International Association of Plumbing and Mechanical

Officials, Sect. 1008(e), p. 76, Los Angeles, Cal . (1973).

14. Southern Standard Plumbing Code , Southern Building Code Congress, Sect. 107.6,

p. 7, Birmingham, Ala. (1971).

15. King, R.C. and Crocker, S., Piping Handbook , 5th ed . , Chap. 7, p. 291, (McGrawHill Book Company, New York, N.Y., 1967).

16. Marks, L.S., Mechanical Engineers fiandbook , 6th ed . , Sect. 16, p. 11, (McGrawHill Book Company, New York, N.Y., 1958).

19
CHAPTER TWO - MECHANICAL

systems and components

17. ASHRAE Handbook and Products Directory, 1974 Applications , Chap. 59, New York,

N.Y, (1974).

t

18. Tabor, H. , "Stationary Mirror Systems for Solar Collectors," Solar Energy , vol. II, pp. 3-4, Pergamon Press, Elmsford, N.Y., (July-October 1958).

19. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards

Institute, New York, N.Y. (1974).

20. Underground Thermal Distribution Systems (35° to 250°F) , Building Research

Advisory Board, National Academy of Sciences - National Research Council,

Washington, D.C. (1970),

21. Thermal Insulation for Piping , Federal Construction Council Technical Report

No. 41, Building Research Advisory Board, National Academy of Sciences

Publication 896, Washington, D.C. (1960).

22. Fundamentals of Underground Corrosion and Cathodic Protection , Federal

Construction Symposium-Workshop Report No. 2, Building Research Advisory

Board, National Academy of Sciences - National Research Council Publication 1097, Washington, D.C. (1963).

23. Evaluation of Components for Underground Heat Distribution Systems , Federal

Construction Council Technical Report No. 39-64, National Academy of Sciences • National Research Council Publication 1196, Washington, D.C. (1964).

*Available from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

tAvailable from American Society of Heating, Refrigerating and Air -Conditioning

Engineers, Inc., 345 East 47th Street, New York, N.Y. 10017.

20
CHAPTER THREE - STRUCTURAL

systems and components

3.1 Requirement Structural design basis . The structural design of the heating (H)

,

combined heating and cooling (HC) and domestic hot water (DHW) systems

including connections and supporting structural elements shall be in

accordance with nationally recognized codes and standards and shall be

based on loads anticipated during the service life of the systems.

3.1.1 Criterion Applicable standards . The structural design and construction of H, HC

and DHW systems including connections and structural supports thereof

shall comply with the following provisions:

Conventional elements* shall comply with the provisions of the HUD

Minimum Property Standards (MPS)[1] for single family and multifamily

housing or ANSI A119.1[4], in the case of mobile homes, and such additional criteria as specified in this chapter. Non-conventional

elements** shall comply with all the criteria stipulated in this chapter,

Evaluation Review of drawings, specifications and structural calculations.

Commentary In addition to complying with the design and construction provisions of

the MPS or ANSI A119.1 (for mobile homes), conventional elements and

connections are required to comply with Criteria 3.1.2 (Service loads),

3.2.2 (Ice loads), 3.2.3 (Vehicular loads), 3.5.1 (Design provisions - cutting of structural elements), 3.7.1 (Hail size and loading), and

3.9.1 (Design provisions - ponding conditions).

3.1.2 Criterion Service loads . The following loads shall be used in the structural

design of conventional and non-conventional elements and connections

of H, HC and DHW systems:

1. Dead loads (D) shall be the "Design Dead Loads" stipulated in

Section 601-3 of the MPS.

2. Live loads (L) shall be all applicable "Design Live Loads" stipulated in Section 601-4 and "Snow Loads" stipulated in Section 601-5

of the MPS.

3. Wind loads (W) shall be "Wind Loads" stipulated in Section 601-6. of

the MPS. In all cases consideration of local wind conditions shall

be assured by compliance with Section 6.3.3 of ANSI A58.1[2].

4. Earthquake loads (E) shall be those stipulated in Section 601-9

of the MPS which references the provisions of the Uniform Building

Code (UBC) [3]. For non-conventional system components and con- nections, the value of "Cp" used in the UBC shall be taken as 2.0.

* Conventional elements and connections (as used in this chapter) are defined as those

elements and connections for which the design and construction provisions of the

Minimum Property Standards (MPS) or ANSI A119.1 are applicable.

** Non-conventional elements and connections are defined as those elements and connections

for which the design and construction provisions of MPS or ANSI A119.1 are not applicable.

21
CHAPTER THREE - STRUCTURAL

systems and components

5. Constraint loads caused by the environment, normal functioning of

the system and time-dependent changes within the materials of the

system shall be taken as the* most severe likely to be encountered

during the service life.

6. Constraint loads induced by differential foundation settlement shall

be taken as those corresponding to a differential foundation settlement of the magnitude stated under Criterion 3.8.1.

7. Ice loads (I) shall be taken as those produced by the accumulation

of ice on surfaces exposed to the natural environment. The thick- ness of ice shall be determined in accordance with Criterion 3.2.2.

8. Hail loads (H) shall be taken as those produced by the impact of

hail on surfaces exposed to the natural environment. Hail particle

size and kinetic energy at impact shall be determined in accordance

with Criterion 3.7.1.

9. Vehicular loads on below grade installations shall be determined in

accordance with Criterion 3.2.3.

Evaluation For experimental or analytical evaluation of structural response, the

selection of system components shall be done in a manner representing

.. the least margin of safety to the system but consistent with its interaction with structural systems to which they are attached . Test loads

; applied to the system components shall result in the most critical

-

. conditions encountered in service. Additional eccentricities of loading caused by drift due to lateral loads and anticipated differential

foundation settlements shall be provided for in tests of supporting

structural elements of the system. The effects of service history

caused by fatigue, sustained load, temperature, moisture, ultraviolet

light or other environmental factors, shall be provided for in tests.

Commentary The intent of the criterion is to state the required reliability of

performance and, therefore, the specified loads should have a defined

probability of occurrence.

The assumption is made (with the exception of wind and snow loads, which

are based on statistical analysis) that the MPS "design loads" are

' loads anticipated during the service life of the system.

The minimum uniformly distributed live load on relatively flat horizontal and inclined surfaces of the system is taken in accordance

with roof loads prescribed by MPS. Snow load is based on ANSI A58.1

and is treated as live load in lieu of the MPS roof load if it produces

a more severe loading condition. This is consistent with MPS which

uses ANSI A58.1 by reference.

r Earthquake loads are determined by the applicable provisions of the

i Uniform Building Code. It is recognized that for cases involving new material applications it may be difficult to select the appropriate Cp factor. The prescribed Cp value intended for use with non- conventional elements and connections is consistent with the values

specified in UBC for connections of exterior panels.

22
CHAPTER THREE - STRUCTURAL

systems and components

3.2 Requirement. Failure loads and load capacity . The structural elements and connections

of the H, HC and DHW systems shall not fail under ultimate loads ex- pected during the service life of the system.

3.2.1 Criterion Ultimate load combinations . Non-conventional elements and connections

shall comply with this criterion. (Conventional elements and connections

are deemed to satisfy this criterion.)

Structural components, connections and supporting elements shall be

designed for the following ultimate load combinations:

(1) 1.4 D + 1.7 L

(2) 0.9 D + 1.7 W

(3) 0.9 D + 1.45 E

(4) 1.1 D + 1.3 L + 1.7 W

(5) 1.1 D + 1.3 L + 1.45 E

where the multipliers are load factors and the letters are the service

loads defined in Criterion 3.1.2.

Evaluation Review of structural calculations, specifications and drawings.

Commentary The intent of the criterion (along with Criterion 3.2.4) is_ to provide

a minimum level of safety against loading situations which have a suitably low probability of occurrence during the service life. The

load factors represent present-day design practice for building structures

and are similar to the load factors used in ACI 318[5]. These factors

• - will produce ultimate loads comparable to those presently used in the

design of steel structures. Adoption of similar levels of performance

requirements for the H, HC and DHW systems will also permit the designer

to explore the potential use of system components as structural elements

for purposes of providing enclosure or diaphragm rigidity to the supporting structure in addition to their primary heating and/or cooling

function.

3.2.2 Criterion Ice Loads .

(a) Above-ground installations of conventional elements for which ultimate

design provisions apply, and of all non-conventional elements, including connections and structural supports thereof, shall comply

with Criterion 3.2.1 for load combinations (1) and (4) in which live

. , load (L) shall be taken as that produced by the accumulation of ice

on all surfaces exposed to the natural environment.

(b) Above-ground installations of conventional elements for which working

stress design provisions apply, including connections and structural

supports thereof, shall comply with Criterion 3.2.2(a) with the

following modification: load factors in load combinations (1) and

(4) of Criterion 3.2.1 shall be taken as 1.0.

(The radial thickness of ice around the circumference of exposed wires,

pipes, and structural members shall be based on the annual frequency of occurrence of glaze shown in Figure 3.2.2 (see reference [6]) and shall

'be computed as follows:

Mean annual number under 1 1-4 4-8 over 8 of days with glaze

Thickness of ice 0

(inches)

23

1/2 3/4 1.0
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CHAPTER THREE - STRUCTURAL

systems and components

Evaluation Review of structural calculations.

Commentary The intent of this criterion is to account for the effect of ice loads

primarily on wires, pipes and other similar components which are exposed to the natural . environment , in recognition of the fact that

ice storms have been particularly detrimental to such components

in the past.

The map- of Figure 3.2.2 with documented information of the accumulation

of ice recorded for major ice storms [6] and ice loads considered in

the design of steel transmission pole structures [7] have been utilized

to relate thickness of ice to frequency of occurrence of such storms.

This assumption is made in view of a lack of statistical data on accumulation of ice and should result in a generally conservative

practice even though it is recognized that thickness of ice cannot be

solely expressed in terms of rate of occurrence.

3.2.3 Criterion Vehicular Loads .

(a) Below grade installation of conventional elements for which ultimate design provisions apply, and of all non-conventional elements,

including connections and structural supports thereof, subjected

to heavy vehicular traffic shall not fail under load combination

(1) of Criterion 3.2.1 where dead load (D) and live load (L) are calculated in accordance with the AASHO provisions on "distribution

of loads through earth fills [8]. For sites other than those

specifically designed for general public and commercial vehicular

traffic, the wheel loads shall be taken as those induced by an AASHO H20-44 truck without impact.

(b) Conventional elements for which working stress design provisions

apply shall comply with Criterion 3.2.3(a) with the following

modification: load factors in load combinations (1) and (4) of

Criterion 3.2.1 shall be taken as 1.0.

Evaluation Analysis using the principles of soil mechanics for specified conditions

of bedding and backfill.

Commentary The criterion specifies the level of vehicular traffic for which buried

components should be designed in cases where heavy vehicular traffic

is anticipated to occur in service for purposes of access. The H20-44

truck is considered to be representative of load levels associated with

heavy vehicles such as trucks for repair, maintenance, moving, and

delivery of fuel.

25
CHAPTER THREE - STRUCTURAL

systems and components

3.2.4 Criterion Load Capacity . Non-conventional elements and connections shall comply

with this criterion. (Conventional elements are deemed to satisfy this

criterion.)

The load capacity, R, of the system or a portion thereof shall exceed the required ultimate load, U, in Criterion 3.2.1 and shall

be derived from the mean load capacity R : m

'

' U < R = R 0 c — m u where

:

0 = variability factor which shall be such that approximately 95%

of the system or portions thereof exceed Riii0 in resistance.

,.: For normal distribution of resistance, 0 = 1- 1.65v.

V = coefficient of variation of resistance with respect to R . m

c^ = coefficient for ductility = (m + 7)/12, but not more than

1.0 for loadings not including earthquake, and equal to 1.0

for loadings including earthquake.

y = ductility factor for loading condition U, as defined under

Evaluation below.

Evaluation Where adequate existing test data on the various material properties

comprising the system are available, evaluation will be performed using

engineering analysis. Where adequate test data is unavailable, system

- elements and subassemblies will be evaluated in the laboratory using

simulated static load levels consistent with the specified load combinations.

The ductility factor will be evaluated as follows: For an ideal elastoplastic (elastic-perfectly plastic) resistance function (plot of

applied load as ordinate and deflection as abscissa) , the ductility

factor is defined as the ratio of ultimate deflection to yield deflection

(p = d^ / dye)* For an actual (nonlinear) function, the ductility

factor shall be computed from an "effective" function (Fig. 3.2.4). The

effective function consists of 2 straight lines. The first line is

drawn through the origin and a point on the actual function at which the

resistance is 60 percent of its maximum load value (Pu) • The second

line is a horizontal line ending at the ultimate deflection (d^) , which

shall not exceed that where the resistance function falls below 95

percent of its maximum load value. The horizontal line is located so that the area under the 2 lines foirming the effective function is equal

to the area under the actual function up to the point of ultimate deflection. Effective yield deflection (dyg) shall be taken as the

deflection at the point of intersection of the 2 lines, which is at a resistance level termed "effective yield resistance." The ductility

factor is based on the effective resistance function: p = d^/dyg.

Commentary The intent of this criterion (along with Criterion 3.2.1) is to provide

a minimum level of safety against loading situations which have a suitably low probability of occurrence during service life.

26
CHAPTER THREE - STRUCTURAL

systems and components

EFFECTIVE RESISTANCE FUNCTION

A|+ A2+ A4

FIG. 3.2.4. DETERMINATION OF THE DUCTILITY FACTOR

27
CHAPTER THREE - STRUCTURAL

systems and components

3.3 Requirement' Damage control . The structural elements and connections of H, HC and

DHW systems shall be designed to withstand service loads without damage

of unacceptable magnitude.

3.3.1 Criterion Resistance to damage . Non-conventional elements and connections shall

comply with this criterion. (Conventional elements and connections are deemed to satisfy this criterion.)

Under the effect of deflections caused by loading combinations of (1),

(2) and (4) of Criterion 3.2.1, with load factors of 1.0, in addition

to the anticipated creep deflections, the system as a whole or any

... component, connection or support thereof, shall not suffer permanent

damage which would require replacement or repair, or which would impair

its intended function during its service life.

Evaluation Evaluation of documented data for design, tests, and installation.

Evaluation and/or testing of components and elements where deemed

essential. Determination of compliance with generally accepted

standards and engineering and trade practices, where applicable.

The criterion is deemed satisfied if it can be demonstrated that

deflections caused by the specified load combinations can be accom- modated by suitable details or adequate flexibility.

Commentary The intent of this criterion is to provide for the proper functioning

of the system under service loading conditions without breakdown or permanent impairment beyond levels comparable to conventional heating

and cooling systems.

3.3.2 Criterion Glazing design . The selection and installation of glazing materials

shall be in accordance with sections 508 and 608 of the MPS and

Part B of ANSI A119.1, where applicable.

Evaluation Review of drawings and specifications. Testing to show compliance,

where necessary.

Commentary This criterion is intended to deal with potential hazards that could

occur when frangible materials such as glass are used in applications

such as collector cover plates.

3.4 Requirement Cyclic loads . The structural elements and connections of H, HC and

DHW systems shall not fail under the application of cyclic loads

expected during the service life.

28
CHAPTER THREE - STRUCTURAL

systems and components

3.4.1 Criterion Deflection limitations . Non-conventional elements and connections shall

comply with this criterion. (Conventional elements and connections are deemed to satisfy this criterion.)

Structural components, connections and supporting elements shall be

capable of resisting the following repeated loads without failure and

without a residual deflection in excess of 25 percent of the maximum

deflection measured in the first cycle of load application:

(1) 100 cycles from 1.0 D to 1.0 D + 0.5 L

(2) 1000 cycles from 1.0 D to 1.0 D + 0.5 W

Evaluation Physical simulation and testing or analysis based on available test

data

.

The cyclic loading (1) and (2) shall be assumed to be applied after

reducing system slack by the prior application of one preloading cycle

of the following loads:

for (1) from (ID) to (ID + IL)

for (2) from (ID) to (ID + IW)

Cyclic loading shall commence only after deflection recovery from the

preloading cycle is substantially complete. The residual deflection

shall be taken as the difference between the deflection measured 24 hours after removal of the superimposed cyclic load and the residual

deflection, if any, not recovered from the preloading cycle.

Commentary Even though the service load history cannot be simulated the imposition

of the stipulated cyclic loads is intended as a conservative representation of service conditions. The residual deflection limitation assures preservation of structural integrity under cyclic loading.

3.5 Requirement Cutting of structural elements . Cutting of structural elements for the

installation of H, HC and DHW system components shall not reduce the

required load capacity of structural elements.

3.5.1 Criterion Design provisions . The effect on the size, shape or engineering properties of a load-bearing element resulting from holes, copes, notches,

etc., shall be determined to insure that required safety margins

against failure have been maintained.

Evaluation Review and evaluation of drawings, specifications, structural calculations. Analysis of the altered structural configuration to ascertain

that the required safety margins are not reduced.

Commentary Arbitrary drilling, punching, or other reductions in size or cross section of supporting structural elements in order to provide passage

of system components can seriously reduce structural capacity of the

system.

29
CHAPTER THREE STRUCTURAL

systems and components

3.6 Requirement Creep and residual deflection . The load capacity of structural con- nections and elements supporting the H, HC and DHW system components

shall not be impaired by the effect of creep and residual deflections.

3.6.1 Criterion Deflection limitations . Non-conventional elements and connections shall

comply with this criterion. (Conventional elements and connections are deemed to satisfy this criterion.)

(a) Load capacity shall be evaluated taking into consideration the

effect of creep and residual deflections. The deflection of

- structural elements supporting the system components shall not

exceed the following limitations:

With the full dead- load (1.0 D) in place, the maximum deflection

due to a superimposed load of 0.2D + 1.5L, sustained for 24 hours

shall not exceed

1.25s . 0.2D + 1.5L

;

' 180 L where s = span length.

(b) The maximum residual deflection measured not more than-24 hours

; after removal of the superimposed load specified in (a) shall

not exceed

0.25s

180

Evaluation Analysis and/or physical simulation including tests on prototype

supporting structures. Deflections shall be measured in a direction

normal to the span.

One preloading cycle is permitted, provided that loading in the actual

test does not commence before deflection recovery from the preloading

cycle is substantially complete.

Commentary Loads lower than required ultimate loads should not cause large,

irrecoverable deformations. It is not unreasonable to require non- conventional structures to resist the stipulated superimposed loads

without resulting in significant residual deformations. The limitation

in part (a) implies deflection limitation of s/180 under service live

load (1.0 L) with an additional 25 percent allowance for creep.

Part (b) requires 75 percent elastic recovery of deflection. This

guards against significant residual deflection increases in each cycle

of loading that may lead to incremental collapse.

3.7 Requirement Hail resistance . H, HC and DHW system components and supporting structural elements exposed to the natural environment shall be capable of

resisting impact by hail without unacceptable damage.

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CHAPTER THREE - STRUCTURAL

systems and components

3.7.1 Criterion Hail size and loading . System components and supporting structural

elements that will be exposed to the natural environment in service

shall be designed to resist, without excessive damage or major impairment of the functioning of the system, the perpendicular impact of falling

hail having a particle diameter (in inches) equal to 0.3d where d is the mean annual number of days with hail determined on the basis of the hail

map shown in Figure 3.7.1 [6].

Evaluation Evaluatior will be based on analysis using known structural information

on the physical characteristics of the system components or on physical

simulation and testing using the NBS hail resistance test described in

the NBS Building Science Series 23[9]. In the absence of physical test data, the portion of the kinetic energy dissipated by system components

shall be taken as 50 percent of the kinetic energy at impact corresponding

to the resultant velocity specified in Table 3.7.1 (reproduced from Ref.

[10]) for the predetermined hail size.

In cases where protective measures are provided to prevent impact of

hail on system components, such as the use of screens or deflectors,

these protective measures shall be included in the test specimens.

Commentary It is not the intent of this criterion to prevent punching or local

cracking of nonstructural elements such as glass cover plates of

collector panels under hail impact, but rather to control damage by

keeping it at a level which would not create a major curtailment in the

functioning of the system, premature failure or hazards created by

excessive shattering of glazed elements.

The correlation of hail size with mean annual number of days with hail

is based on studies on the probability of exceedance of a given particle

size as a function of frequency of occurrence of hail, a twenty year recurrence interval reflecting the life expectancy of the system and

observations of statistical data [11] indicating that a representative

hailstorm area is generally one order of magnitude smaller than the

regions for which statistical information is compiled.

3.8 Requirement Constraint loads . The structural elements and connections of H, HC and

DHW systems shall comply with Criterion 3.2.1 while simultaneously

subjected to constraint loads expected during the service life.

3.8.1 Criterion Foundation settlement; contraction and expansion . Non-conventional

elements and connections shall comply with this criterion. (Conventional

elements and connections are deemed to satisfy this criterion.)

31
32
CHAPTER THREE - STRUCTURAL

systems and components

TABLE 3.7.1

Values of weight, terminal velocity, resultant velocity

and kinetic energy computed for smooth ice spheres.

Terminal Resultant Kinetic^

Diameter Weight Velocity Velocity Energy —

in gm lb ft/sec ft/sec ft- lb

1/2 0.98 0.002 51 83 0.09 0.24

3/4 3.30 0.007 62 91 0.44 0.94

1 7.85 0.017 73 98 1.43 2.58

1 1/4 15.33 0.034 82 105 3.53 5.79

1 1/2 26.50 0.058 90 112 7.35 11.38

1 3/4 42.08 0.093 97 117 13.56 19.73

2 62.81 0.138 105 124 23.71 33.07

2 1/4 • 89.43 0.197 111 129 37.73 50.96

2 1/2 122.67 0.270 117 134 57.48 75.39

2 3/4 163.28 0.360 124 140 85.95 109.57

3 211.98 0.467 130 146 122.66 154.71

\j First value corresponds to the terminal velocity and the second ~ value corresponds to the resultant velocity.

33
CHAPTER THREE STRUCTURAL

systems and components

System components, connections and supporting elements shall comply

with Criterion 3.2.1 while simultaneously subjected to the following

constraint conditions:

1. A differential foundation settlement of 2 inches in any horizontal

distance of 50 feet except that in cases where the foundation at

a particular site is specifically designed to control differential

settlements, the constraint conditions should be those consistent

with the specified design. Uplift forces caused by a swelling of

expansive soils shall be calculated assuming a level of 0.9D for

gravity loads

.

2. Constraint loads arising from thermal expansion and contraction of

system components and structural elements or from time-dependent

changes within the material.

Evaluation Analysis and/or physical simulation.

Commentary Soil-structure interaction is usually a design function since con- straint loads are dependent on the characteristics of the soil as well as the effects of structural framing. Due to economic considerations in foundation design, the assumption is usually made that the

superstructure is capable of accommodating a reasonable amount of

differential settlement. The requirement in part (1) is consistent

with observed performance of conventionally designed foundations and

represents the threshold at which structural damage occurs. This

criterion is relaxed when special precautions are used in foundation

design to control differential settlements.

The requirements in part (2) of the criterion account for other types

of constraint loads such as those introduced by thermal expansion

and contraction of system components or creep and shrinkage in supporting structural elements.

3.9 Requirement Ponding conditions . Horizontal surfaces of the H, HC and DHW systems

shall be designed in a manner that will assure stability in service

under ponding conditions.

3.9.1 Criterion Design provisions . Horizontal surfaces exposed to the exterior environment shall be designed to have either sufficient stiffness to prevent

failure as a result of ponding caused by the accumulation of water or shall be provided with sufficient slope to permit free drainage or adequate individual drains to prevent the accumulation of water.

34
CHAPTER THREE - STRUCTURAL

systems and components

Evaluation Analysis based on documented strength and stiffness properties or physical simulation and testing.

Commentary Ponding Is defined as the retention of water due to the deflection of

horizontal surfaces. The lack of sufficient vertical stiffness causes

the surface to continuously deflect and accumulate additional water

until collapse occurs.

35
CHAPTER THREE - STRUCTURAL

systems and components

References

1. HUD Minimum Property Standards, One and Two Family Dwellings (No, 4900.1),

U.S. Department of Housing and Urban Development, Washington, D.C. (1973,

revised 1974)* and HUD Minimum Property Standards, Multlfamily Housing

(No. 4910.1), U.S. Department of Housing and Urban Development, Washington,

D.C. (1973).*

2 . Building Code Requirements for Minimum Design Loads in Buildings and Other

Structures , ANSI A58. 1-1972, American National Standards Institute, New York,

N.Y. (1972).

3. Uniform Building Code , International Conference of Building Officials, Whittler,

Cal. (1973).

4. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards Institute,

New York, N.Y. (1974).

5. Building Code Requirements for Reinforced Concrete , ACI318~71, American Concrete

Institute, Detroit, Mich. (1971).

6. Baldwin, J.L., Climates of the United States , U.S. Department of Commerce,

Washington, D.C. (1973).*

7. "Design of Steel Transmission Pole Structures," Task Committee on Steel

Transmission Poles of the Committee on Analysis and Design of Structures,

Journal of the Structural Division , American Society of Civil Engineers, New

York, N.Y. (December 1974).

8. Standard Specifications for Highway Bridges , American, Association of State Highway

Officials (AASHO), Washington, D.C. (1973).

9. Greenfield, H., Hail Resistance of Roofing Products , Building Science Series 23,

National Bureau of Standards, Washington, D.C. (August 1969).*

10. Mathey, R.G., Hail Resistance Tests of Aluminum Skin Honeycomb Panels for the

Relocatable Lewis Building, Phase II , NBS Report 10 193, National Bureau of

Standards, Washington, D.C. (1970).

11. Storm Data , U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Data Service (monthly periodical).

*Available from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

36
CHAPTER FOUR - SAFETY

systems and components

4.1 Requirement Plumbing and electrical installation . The design and installation of

the systems for heating (H) , combined heating and cooling (HC) and the

domestic hot water (DHW) system/subsystem and their components shall be

in accordance with nationally recognized plumbing and electrical codes

and standards for health and safety, where applicable.

4.1.1 Criterion Plumbing codes and standards . Plumbing materials and equipment and

their installation shall be in accordance with Sections 515 and 615

of the MPS (4900.1 and 4910. 1)[1] and Part C of ANSI A119.1[2], where

applicable

.

Evaluation Review of drawings and specifications,

where necessary.

Testing to show compliance,

Commentary Suitable standards are available for conventional equipment. Unique

innovative installations may require special consideration.

4.1.2 Criterion Electrical codes and standards . Electrical materials and equipment

and their installation shall be in accordance with Sections 516 and

616 of the MPS (4900.1 and 4910.1)11] and Part E of ANSI A119.1[2],

where applicable.

Evaluation Review of drawings- and specifications. Testing to show compliance,

where necessary.

Commentary Suitable standards are available for conventional equipment . Unique

installations may require special consideration.

4 . 2 Requirement Fail-safe controls . The H,lte and DHW systems shall be fail-safe in

the event of damage to system components or a power failure.

37
CHAPTER FOUR - SAFETY

systems and components

4.2.1 Criterion System failure prevention . The control subsystem shall be designed so that in the event of a power failure, or a failure of any of the com- ponents in the subsystem, the temperatures and/or pressures developed

in the H, HC and DHW systems will not be damaging to any of the com- ponents of the systems, and the building, or present a danger to the

occupants. The safety devices shall meet the requirements of Section

515-6.4 of the MPS (4900.1 and 4910.1) [1].

Evaluation Review of drawings, specifications and design calculations.

Perform test of fail-safe control installation for all probable

failure events.

Commentary The excessive pressures and temperatures that can build up in collectors under "no flow" conditions are an important consideration.

Consideration should be given to the thermal shock. vhich could occur when cool heat transfer fluids are introduced into collectors which

have been exposed to solar radiation under "no flow" conditions.

4.2.2 Criterion Automatic pressure relief valves . Adequately sized and responsive

, . . automatic pressure relief valves shall be provided in those parts

of the energy transport subsystem containing pressurized fluids*

' » Automatic pressure relief valves shall be set to open at not less

than 25 percent in excess of working pressure and at not more than

maximum pressure for which the subsystem is designed.

Evaluation Review of plans and specifications, and/or determination that methods,

devices, and materials to be used are approved by a recognized testing

and evaluation agency as being suitable for the proposed use.

4.3 Requirement Fire safety . The design and installation of the H, HC and DHW systems

and their components shall provide a minimum level of fire safety

consistant with applicable codes and standards.

4.3.1 Criterion Applicable fire standards . Assemblies and the materials used in the

H, HC and DHW systems shall comply with nationally recognized codes and

standards for fire safety, where applicable.

Evaluation Review of drawings and specifications for conformance with the MPS,

ANSI A119.1, and applicable sections of NFPA 89M[4] , NFPA 90A and

90B[5], NFPA 211[6], NFPA 54[7], NFPA 31[8], ASTM E 108[9] and the

National Electric Code [10]. Testing to show compliance, when necessary. Potential heat, rate of heat release, ease of ignition, and

smoke generation will be considered in assessing potential fire

hazards.

38
CHAPTER FOUR ,- SAFETY

systems and components

Commentary It is the intent of this criterion to (1) prevent the use of materials,

equipment and fluids which present a fire hazard significantly greater

than that of conventional systems, (2) to provide proper clearances and

venting of heat build-up for those system components that operate

at elevated temperatures, and (3) to give consideration to the com- bustibility of materials adjacent to high temperature components in

determining the clearances that are required

.

4.3.2 Criterion Penetrations through fire-rated assemblies . Penetrations through fire

rated walls, partitions, floors, roofs, etc. shall not reduce the

fire resistance below the levels specified in Section 405 of the

MPS (4900.1 and 4910.1) [1], where applicable.

Evaluation Review of drawings and specifications. Testing to show compliance,

where necessary.

Commentary It is the intent of this criterion (1) to prevent the passage of

system components through fire-rated assemblies from adversely

affecting the fire endurance rating of the assembly, and (2) to ensure

that proper techniques are employed in constructing these components

so that adequate protec1:ion can be provided.

4.4 Requirement Toxic and flammable fluids . Heat transfer fluids which require special

handling because of toxicity and/or flammability shall not be used

unless the systems in which they are used are designed to avoid exposing

the occupants of dwellings to unreasonable hazards.

4.4.1 Criterion Provision of catch basins . Adequately sized and protected catch

basins shall be provided, when liquids requiring special handling

are used, to collect and store the overflow from pressure relief

valves, liquids drained from the system when it is being serviced,

potential leakage, and accidental drainage.

Evaluation Review of drawings and specifications.

Commentary The leakage of toxic fluids into the ground could contaminate the

ground water.

4.4.2 Criterion Detection of toxic and flammable fluids . If heat transfer fluids that

require special handling are used, means shall be provided for the

detection of leaks and the warning of occupants when leaks occur.

Evaluation Review of drawings and specifications. Testing of detection and

warning system(s)

.

Commentary It is common practice to relate toxicity and flammability ratings to the level of hazard created at ambient temperatures. Heat transfer

39
CHAPTER FOUR - SAFETY

systems and components

fluids which do not present a hazard at ambient temperatures may be

hazardous at the temperatures developed in the system.

4.5 Requirement Safety under emergency conditions . In the event of emergencies , the

H, HC and DHW systems shall not unduly hinder the movement of occupants

of the building or emergency personnel. Life safety hazards which

could occur as a result of failures of the above systems shall not be

greater than those imposed by conventional systems.

4.5.1 Criterion

Evaluation

Commentary

Emergency egress and access . The design and installation of the H, HC

and DHW systems shall not impair the emergency movement of occupants of

the building or emergency personnel to an extent greater than that

allowed by Sections 402 and 405 of the MPS (4900.1 and 4910.1) [1] and

NFPA 101 [3], where applicable.

Review of drawings and specifications.

The location of exits and passageways as related to the H, HC and DHW

systems is an important consideration.

4.5.2 Criterion Identification and location of controls . Main shutoff valves and

switches shall be conspicuously marked and placed in easily acces-

: sible locations.

Evaluation Review of drawings and specifications.

4.6 Requirement Protection of potable water and circulated air . No material, form of

construction, fixture, appurtenance or item of equipment shall be

employed that will support the growth, of micro-organisms or introduce

toxic substances, impurities, bacteria or chemicals into potable water

and air circulation systems in quantities sufficient to cause disease

or harmful physiological effects.

4.6.1 Criterion

Evaluation

Contamination by materials . Materials which come in direct contact

with potable water shall not affect the taste, odor or physical quality

and appearance of the water in an undesirable manner.

Review of plans and specifications for compliance with the 1962

Edition of the Public Health Service Drinking Water Standards [11]

.

40
CHAPTER FOUR - SAFETY

systems and components

4.6.2 Criterion Separation of circulation loops . Circulation loops of subsystems

utilizing nonpotable heat transfer fluids shall be separated from the

potable water system in such a manner that leakage will not contaminate the potable water supply.

Evaluation Review of drawings and specifications.

4.6.3 Criterion Backflow prevention . Backflow of nonpotable heat transfer fluids

into the potable water systems shall be prevented

.

Evaluation Review of drawings and specifications. Inspection of assembled

systems

.

Commentary Pollution of the potable water supply can occur by way of backflow

caused by back pressure and/or backsiphonage within a cross connection between the potable supply and nonpotable fluid in the system.

The former type of backflow can occur, for example, from elevated

tanks, or pumps. The latter can occur when the potable water supply

system is under vacuum such as might occur with a broken street water

main

.

Piping arrangements, backflow prevention devices, and/or air gaps

may be used to prevent contamination of the potable water system.

4.6.4 Criterion Growth of fungi . Components and materials used in the H, HC and DHW

systems shall not promote the growth of fungi, mold or mildew.

Evaluation When tested in accordance with Appendix D, Section E of the MPS

(4900.1 and 4910.1) [1], there should be no evidence of the growth of

fungi

.

Commentary Special consideration should be given to the presence of fungi in

air handling systems since such micro-organisms are frequently

allergenic.

Fungi can feed on some organic materials and generally thrive in warm, moist environments. They can be killed by sufficiently low wavelength

ultraviolet radiation but much of this radiation may be absorbed by

the earth's atmosphere. It may be possible for fungi to grow on both

the interior and exterior of collector components and possibly affect

the collector performance.

41
CHAPTER FOUR - SAFETY

systems and components

4.7 Requirement Excessive surface temperatures . Temperatures of exterior surfaces of

the H, HC and DHW systems shall not create a hazard.

4.7.1 Criterion Protection from heated components . Subassemblies of the H, HC and DHW

systems that are accessible, located in areas normally subjected to

• ' ' public traffic and which are maintained at elevated temperatures

5 ^ shall either be insulated to maintain their surface temperatures at or below 140 F at all times during their operation- or suitably isolated,

Any other exposed areas that are maintained at hazardous temperatures

shall be identified ;«7ith appropriate warning signs.

Evaluation Review of drawings and specifications.

42
CHAPTER FOUR - SAFETY

systems and components

References

1. HUD Minimum Property Standards, One and Two Family Dwellings (No. 4900.1), U.S.

Department of Housing and Urban Development, Washington, D.C. (197 3, revised

1974)t and HUD Minimum Property Standards, Multifamily Housing (No. 4910.1),

U.S. Department of Housing and Urban Development, Washington, D.C.t

2. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards

Institute, New York, N.Y. (1974).

3. Life Safety Code , NFPA No. 101, National Fire Protection Association,

Boston, Mass. (1973) .*

4. Clearances for Heat Producing Appliances , NFPA No. 89M, National Fire

Protection Association, Boston, Mass. (1971).*

5. Air Conditioning and Ventilating Systems , NFPA No. 90A, National Fire

Protection Association, Boston, Mass. (1973)* and Warm Air Heating and

Air Conditioning Systems , NFPA No. 90B, National Fire Protection Association, Boston, Mass. (1973).*

6. Chimneys, Fireplaces and Vents , NFPA No. 211, National Fire Protection

Association, Boston, Mass. (1972).*

7. Gas Appliances and Gas Piping , NFPA No. 54, National Fire Protection

Association, Boston, Mass. (1969).*

8. Oil Burning Equipment , NFPA No. 31, National Fire Protection Association,

Boston, Mass. (1972) .*

9. Fire Tests of Roof Coverings , ASTM E 108-58, American Society for Testing

Materials, Philadelphia, Pa. (1970).

10. National Electric Code , National Fire Protection Association, Boston,

Mass. (1971).*

11. The Public Health Service Drinking Water Standards , U.S. Department of

Health, Education and Welfare, Washington, D.C. (1962).

*Available from National Fire Protection Association (NFPA), 470 Atlantic Avenue,

Boston, Mass. 02210.

tAvallable from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

5.1 Requirement Effects of external environment . The systems for heating (H) and

combined heating and cooling (HC) and the domestic hot water (DHW)

system/subsystem and their various subassemblies shall not be affected

by external environmental factors to an extent that will significantly

impair their function during their design life.

5.1.1 Criterion Solar deg^radation . Components or materials that are exposed to sunlight shall not undergo changes in their properties during their design

life that would significantly impair the function of the system.

a. When components or materials are exposed to UV radiation in

combination with an intermittent water spray at their maximum

"no-flow" temperature, there shall be no signs of excessive

deterioration such as cracking, crazing, embrittlement , etching,

loss of adhesion, changes in permeability, loss in flexural strength

or any other changes that would significantly affect the performance

of the components in the system.

b. The collector shall be capable of providing its rated output after

exposure to levels and intensities of solar radiation and temperatures that are equivalent to those that would be expected in

actual use over the life of the collector.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

03 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary The transmittance , emittance and absorptance data required to estimate

the effects of degradation by solar radiation in reducing the collector efficiency are available for most materials currently being used

in collectors.

The maximum "no flow" temperature and other in-use temperatures are discussed in detail in Section 01 of the Appendix at the end of this

chapter.

5.1.2 Criterion Soil corrosion . Components that are intended to be buried in soils

shall not degrade under in-use conditions to an extent that their

function will be iippaired during their design life.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

04 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Protective coverings and/or cathodic protection shall be provided if

these protective means are used for protection of the system.

45

"
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Conimentary This criterion is intended to protect against corrosion which can be

caused by soil. The soil conditions will vary from site to site.

5.1.3 Criterion Airborne pollutants . Components that are exposed to airborne pollutants such as ozone, salt spray, SO2 , NOx, and/or HCl with or without

the presence of moisture shall be resistant to attack by these factors

to the extent that these factors shall not significantly impair the

performance of the components during their design life.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

05 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

'. L

i

- The maximum pollutant levels in the area(s) where the system will be

installed shall be used to determine the pollutant levels required for

testing. If components are to be used in areas where they are not

/r- exposed to any or all of these pollutants, tests that are not applic-

,-• able need not be conducted.

Commentary Ozone concentrations in normal dry air have been reported to range

from 1-5 pphm/volume. However, concentrations of 100 pphm/volume have

been reported during very smoggy conditions. Ozone is known to degrade

some organic materials but it has little effect on inorganic materials

other than metals

.

The effects of solar radiation in combination with airborne pollutant

may also be an important consideration.

5.1.4 Criterion Dirt retention on cover plate surface . The collector cover plate

surface shall not collect and retain dirt to an extent that would

significantly impair the function of the collector during its design

life.

Evaluation Engineering analysis, documentation of satisfactory long-term perfor-

. ;: mance under in-use conditions and review of plans and specifications,

Commentary The possible collection and retention of dirt by the cover plate and

the effect of retained dirt on the collector performance may be

significant. The retention of dirt may depend on the tilt angle of

the collector. Rainfall and snow melt are generally sufficient to keep the collector cover plates clean.

46
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

5.1.5 Criterion Abrasive wear . The ability, of the collector to function at its rated

capacity shall not be significantly impaired by the abrasive wear to which its surface will be subjected over its design life.

Evaluation Engineering analysis, documentation of satisfactory long-term

performance under in-use conditions and review of surface hardness

specifications for cover plate materials.

Commentary Test methods which are currently available for measuring abrasion

resistance are believed to be too stringent for testing organic

collector cover plates . Abrasive wear is expected to present a possible problem in areas subject to wind driven sand.

5.1.6 Criterion Fluttering by wind . Components that are subject to fluttering by

wind shall not degrade under in-use conditions to an extent that their

function will be impaired during their design life.

Evaluation Documentation of satisfactory long-term performance under in-use

conditions, engineering analysis, or testing using an experimental

verification procedure which can be shown to meet the Intent of

the criterion.

Commentary Thin films that increase in brittleness at low temperatures may be

particularly susceptible to degradation by fluttering by wind.

5.2 Requirement Temperature and pressure resistance . Comijoiients shall be capable of

performing their intended function for their design life when exposed

to the temperatures and pressures that can be developed in the system.

5.2.1 Criterion Thermal degradation . Components shall not thermally degrade to the

extent that their function will be reduced below acceptable levels

during their design life when exposed to in-use temperatures

.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

Is unavailable, testing using either the methodology outlined in Section

06 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Some organic components which may be used in the system may be

particularly susceptible to thermal degradation under prolonged

exposure

.

47
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

5.2.2 Criterion Deterioration of heat transfer fluids . Except when such changes are allowed by the design of the system, the heat transfer fluid shall not freeze, give rise to excessive precipitation, otherwise lose its

homogeneity, boil, change pH or undergo large changes in viscosity

when exposed to its intended service temperature and pressure range.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

.-, , is unavailable, testing using either the methodology outlined in Section

, , 07 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Thermal cycling may cause metastable precipitation to occur. Systems

may be pressurized to prevent boiling.

5.2.3 Criterion Thermal cycling stresses . The H, HC and DHW systems and their various

subassemblies shall be capable of withstanding the stresses induced

by thermal cycling for their respective design lives.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

08 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

- : Physiical restraints that will be imposed on the system in actual use

shall be considered when testing is required.

Commentary This criterion is intended to identify potential problems that may

occur as a result of differential thermal movement. Thermal compatibility is especially critical in the case of collectors which may

contain large expanses of glazing. Edge flaws in glass may result

in cracking of the glass when it is under stress.

5.2.4 Criterion Leakage . All assemblies or subassemblies which contain heat transfer

fluids (other than air) shall not leak when tested at a pressure equal

to 150% of the working pressure of the system over the entire service

temperature range.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

09 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

48
CHAPTER FIVE DURABILITY / RELIABILITY

systems and components

Commentary This criterion is intended for materials which may creep or become

brittle at service temperatures

.

5.2.5 Criterion Deterioration of gaskets and sealants . Gaskets and sealants in

direct contact with heat transfer liquids shall be capable of

withstanding repeated cycles consisting of soaking and drying

under in-use conditions without significantly impairing their

ability to function during their design life.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

10 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Gaskets, sealants, and similar organic materials frequently swell when

exposed to liquids and shrink upon drying, thus losing their ability

to function.

5.2.6 Criterion Transmission losses due to outgassing . Outgassing of volatiles that

will reduce collector performance below specified design values shall

not occur when the collector is exposed to the temperature and pressures

that will occur in actual service

.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

11 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Outgassing from components inside the collector could lead to condensation on the underside of the collector cover plates which may reduce

the transmissivity of the cover plates

.

5.3 Requirement Chemical compatibility of components . Materials used in the systems

and their various subassemblies shall have sufficient chemical

compatibility to prevent corrosive wear and deterioration that would

significantly shorten the intended service life of components under in- use conditions

.

5.3.1 Criterion Materials/transfer fluid compatibility . Materials designed to be used

in contact with heat transfer fluids shall not be corroded by these

fluids to the extent that their function will be significantly

impaired under in-use conditions during their intended service lives.

49
CHAPTER FIVE DURABILITY / RELIABILITY

systems and components

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

12 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Corrosion by heat transfer fluids could be a serious problem in solar

energy systems.

5.3.2 Criterion Corrosion of dissimilar materials . Non-isolated dissimilar materials

with or without corrosion resistant finishes, where used either in

contact with a transfer fluid, or without such contact, shall not be

corroded to the extent that their function will be significantly

impaired under in-use conditions during their intended service lives.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

13 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary The use of corrosion inhibitors or dielectric fittings that electrically isolate dissimilar materials may be desirable. In the case of

plastics, plasticizer migration may be a concern. The presence of

pinholes in protective coatings may drastically accelerate corrosive

• action.

5.3.3 Criterion Corrosion by leachable substances . Chemical substances that can be

leached by moisture from any of the materials within the system shall

not cause corrosive deterioration of any other components that would

significantly impair the ability of these components to perform their

intended function over their service lives

.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

14 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Salts such as those that can be leached by moisture from some types

of glass fiber and mineral wool insulation or from organic components

may cause corrosion of system components that are in close proximity.

50
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

5.3.4 Criterion Effects of decomposition products . Chemical decomposition products

that are expelled from components under in-use conditions shall not cause the degradation of other components within the system to the

extent that it would significantly impair their ability to perform

their intended function over their service lives

.

Evaluation Documentation of satisfactory long term performance under in-use

conditions or engineering analysis. Where adequate existing information

is unavailable, testing using either the methodology outlined in Section

15 of the Appendix given at the end of this chapter or other methods

which can be shown to meet the intent of the criterion will be used.

Commentary Some components may yield degradation products during their service

life without impairing their function or aesthetic properties . These

degradation products could significantly impair the performance of

other components in the system.

5.4 Requirement Components involving moving parts . Components that involve moving

parts, with normal maintenance, shall be capable of performing their

intended function without excessive wear or deterioration for their

service lives

.

5.4.1 Criterion Wear and fatigue . Check valves, pressure regulators, pumps, electrical

switches, and similar components shall be capable of operating under

in-use conditions for their intended lifespans without exhibiting wear

or fatigue that would reduce their performance below specified levels.

Evaluation Documentation of satisfactory long-term performance under in-use

conditions, engineering analysis, or testing using an experimental

verification procedure which can be shown to meet the intent of the

criterion. Either the number of cycles that would be expected in

actual service under in-use conditions, or an accelerated procedure

shall be used for experimental verification.

Commentary In some applications , less expensive components which are readily

replaced but have shorter expected lifespans may be more desirable

than more reliable but more costly components.

Inclusion of the heat transfer fluid during tests of components with

moving parts may be helpful. In particular, very hard crystalline

precipitates may be formed from some types of heat transfer fluids

and their additives.

51
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Saction Ql - Temperature Conditions

Many of the criteria given In this chapter contain reference to the maximum or minimum

service temperatures in specifying the temperature at which testing should be performed.

For some test conditions, it is advantageous to specify the maximum service temperature

that occurs when the heat transfer fluid is flowing through the system; for other test

condlt ions, the maximum service temperature when the heat transfer fluid is not flowing

through the system should be used.

The terms used in this chapter to specify temperatures Include: 1) maximum "flow" temperature, 2) maximum "no-flow" temperature, 3) maximum service temperature and 4) minimum

service temperature. The maximum "flow" temperature of a oomponent refers to the maximum

temperature that will be obtained in a component when the heat transfer fluid is flowing

through the system. The maximum "no-flow" temperature of a component refers to the maximum

temperature that will be obtained in a component when the heat transfer fluid is not flowing through the system. There may be a different maximum "flow" temperature for each

component in the system as well as a different maximum "no-flow" temperature. When the

test temperature is specified as the maximum service temperature , the test temperature

should be the higher of the maximum "flow" or maximum "no-flow" temperatures for the

specific component. The minimum service temperature refers to the minimum temperature to which a component will be exposed in actual service, with or without the flow of heat

transfer fluid.

The minimum service temperature to which a component in the system will be exposed will

generally occur when 1) no solar radiation is falling on the collector, 2) the heat transfer fluid is not flowing through the system and 3) the ambient air temperature is at Its lowest level. The no-flow condition mentioned above assumes the flow of the heat transfer

fluid will be stopped when solar radiation is not falling on the collector to avoid pumping

out heat energy. However, if the flow of fluid is not stopped at night, the minimum

service temperature of some components may occur as nocturnal or evaporative cooling takes

place.

The maximum service temperature, to which the collector and components that are in

intimate contact with it will be exposed, will generally occur when the collector is

receiving its maximum level of solar radiation and the heat transfer fluid Is not flowing

through the collector component. Other components, such as those in the heat transfer and

storage subsystems, will generally reach their maximum temperature when the collector is

receiving its maximum level of solar radiation and the heat transfer liquid Is flowing

through the system. The maximum "no-flow" temperature that will occur at various locations

in the collector can be calculated if the ambient temperature, the intensity of insolation,

the number of cover plates, the back and edge losses, and the absorptivity and emisslvlty of

the absorbant surface and other related factors are known.

The type of Information that is required to determine the maximum "no-flow" temperatures in

various locations of collectors is shown in Section 02 of this Appendix.

Section 02 - Typical Figures Showing the Maximum "No-Flow" Temperatures in Various Locations

of Specific Collector Designs

This Section contains four graphs intended to provide assistance in Identifying the maximum

"no-flow" temperatures at various locations in the collector. The five curves on each

graph represent the maximum "no-flow" temperature for each side of two cover plates and

the surface of the absorber. The calculations used to generate the graphs assume: (1) a glass cover plate thickness of 0.125 Inches, (2) air space thicknesses of 0.1875 inches

both between cover plates and between the absorbent surface and the lower cover plate,

(3) zero edge losses, and (4) the incident solar radiation is normal to the collector.

52
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

380

1=300 BTU/HR n-2-STILL AIR-FLAT BLACK ABSORBER-ZERO HEAT REMOVAL FROM THE COLLECTOR

X ABSORBER PLATE TEMPERATURE I T" + COVER PLATE OKIE INNER SURFACE TEMPERATURE

A COVER PLATE ONE OUTER SURFACE TEMPERATURE

O COVER PLATE TWO INNER SURFACE TEMPERATURE

D COVER PLATE TWO OUTER SURFACE TEMPERATURE

340 -

300 -

Li- 260 h

lJ

^ 220 -

bJ

CL 180 -

140 -

100 -

60

T T

40 -20 0

OUTDOOR

20 40 60 80

AIR TEMPERATURE. F

100

Figure A-1. Temperatures at Various Locations in a Collector with a Flat Black

Absorber and Two Glass Cover Plates (Absorptivity = 0.9,

Emissivity = 0.9, I = 300 BTU/Hr. ft. 2)

53
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

LjJ or:

CL

380

340

300

260

220

180

140

100

1=250 BTU/HR FT2-STILL AIR-FLAT BLACK ABSORBER-ZERO HEAT REMOVAL FROM THE COLLECTOR

60

X ABSORBER PLATE TEMPERATURE! 1 T

+ COVER PLATE ONE INNER SURFACE TEMPERATURE

A COVER PLATE ONE OUTER SURFACE TEMPERATURE

O COVER PLATE TWO INNER SURFACE TEMPERATURE a COVER PLATE TWO OUTER SURFACE TEMPERATURE

-40 -20 0 20 40 60 80

OUTDOOR AIR TEMPERATURE. E

100

Figure A-2 Temperatures at Various Locations in a Collector with a Flat Black Asborber

and Tvo Glass Cover Plates (Absorptivity =0.9, Emissivity =09

I = 250 BTU/Hr. ft. 2) '

'

54
550

1=300 BTU/HR FT2-?riLL AIR-SELECTIVE ABSORBER-ZERO HEAT REMOVAL FROM THE COLLECTOR

500 -

450

400

u_ 350

2 300

I

<

250

200

150

100

50

X ABSORBER PLATE TEMPERATURE

+ COVER PLATE ONE INNER SURFACE TEMPERATURE

A COVER PLATE ONE OUTER SURFACE TEMPERATURE

o COVER PLATE TWO INNER SURFACE TEMPERATURE

D COVER PLATE TWO OUTER SURFACE TEMPERATURE

-40 -20 0 20 40 60 80

OUTDOOR AIR TEMPERATURE, F

100

Figure A-3 Temperatures at Various Locations in a Collector with a Selective Absorber

and Two Glass Cover Plates (Absorptivity = 0.9, Emissivity = 0.1,

I = 300 BTU/Hr-. ft. 2)

55
1=250 BTU/H^R FT7 -STIII ^AIR-SFI Fr.TI\^F ARSORRr R-ZFRO HFAT pruny/Al FROM TMF rni I F,

500

450

400

u_ 350

UJ

2 300

I

<

LJ

Q- 250

200

150

100

50

X ABSORBER PLATE TEMPERATURE

+ COVER PLATE ONE INNER SURFACE TEMPERATURE

4 COVER PUTE ONE OUTER SURFACE TEMPERATURE

© COVER PLATE TWO INNER SURFACE TEMPERATURE

D COVER PLATE TWO OUTER SURFACE TEMPERATURE

CTOR

-40 -20 0 20 40 60 80 100

OUTDOOR AIR TEMPERATURE, F

Figure A-4 Temperatures at Various Locations in a Collector with a Selective Absorber

and Two Glass Cover Plates (Absorptivity = 0.9, Emissivity = 0.1,

I = 250 BTU/Hr. ft. 2)

56
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Section 03 - Test Methodology: Criteria 5.1.1.(a) and 5.1.1(b)

Part A - Test Methodology; Criterion 5.1.1(a)

Test 1

Expose components or materials to simulated solar radiation fsuch as xenon arc radiation)

for a period of 1000 equivalent sun hours. Test specimens shall be heated during the solar

radiation exposure, to the maximum "flow" temperature to which they will be subjected in

actual service. The exterior surfaces of the components shall be subjected to a water spray

for a period of 5 minutes during each 60 minutes of the light exposure.

Test 2

Expose components or materials (not the same specimens used in Test 1) to simulated solar

radiation (such as xenon arc radiation) for a period of 100 hours . Test specimens shall be

heated, during the solar radiation exposure, to the maximum "no-flow" temperature to which

they will be subjected in actual service. The exterior surfaces of the components shall

be subjected to a water spray for a period of 5 minutes during each 60 minutes of the light

exposure

.

ASTM reference methods for Tests 1 and 2 include G26-70, Operating Light and Water Exposure

Apparatus (Xenon-Arc Type) for Exposure of Nonmetallic Materials, and D2565-70, Operating

Xenon Arc-Type (Water-Cooled) Light and Water Exposure Apparatus for Exposure of Plastics.

At the completion of Tests 1 and 2, the specimens shall exhibit no significant visible signs

of deterioration.

In addition to or in lieu of performing Tests 1 and 2 above, outdoor exposure of components

and materials to solar radiation may be performed. Outdoor exposure shall consist of at least six months exposure during which the mean daily solar radiation is approximately 500

langleys .

ASTM reference methods for outdoor exposure tests include:

G7-69T Atmospheric Environmental Exposure Testing of Non-metallic Materials

D1828-70 Atmospheric Exposure of Adhesive Bonded Joints and Structures

D1014-66 (1973) Conducting Exterior Exposure Tests of Paints on Steel

D1006-73 Conducting Exterior Exposure Tests of Paints on Wood

G2A-73 Conducting Natural Light Exposures Under Glass

Gll-72 Effects of Outdoor Weathering on Pipeline Coatings

D1435-69 Outdoor Weathering of Plastics.

The surfaces of components or materials shall be visually inspected before and after aging

to ensure that no signs of excessive deterioration, such as dimensional changes, cracking,

chalking, or other visually detectable changes which could significantly affect the perfor- mance of the components in the system, are present. The following ASTM evaluative techniques for organic coatings shall be used:

*The mean dally solar radiation for Las Vegas, Nevada and Phoenix, Arizona are 504 and 503

langleys, respectively, according to Environmental Science Services Administration (ESSA)

publication "Local Climatological Data. 1971 Annual Summary".

57
CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

D 714--56 (1970) Evaluating Degree of Blistering of Paints

D 659--44 (1970) Evaluating Degree of Resistance to Chalking of Exterior Paints

D 660--44 (1970) Evaluating Degree of Resistance to Checking of Exterior Paints

D 661--44 (1970) Evaluating Degree of Resistance to Cracking of Exterior Paints

Evaluation techniques, in addition to those related to visual inspection, shall also be

used. The methods below represent the types of evaluative techniques that should be used

where applicable: , ,

Vapor Transmission

E 96-66 (1972) Water Vapor Transmission of Materials in Sheet Form

C 355-64 (1973) Water Vapor Transmission of Thick Materials

Tensile Strength

D 638-72 Tensile Properties of Plastics

D 897-72 Tensile Properties of Adhesive Bonds

C 297-61 (1970) Tension Test of -Flat Sandwich Constructions in Flatwise Plane

Flexure Strength

D 790-71 Flexural Properties of Plastics

C 393-62 (1970) Flexure Test of Flat Sandwich Constructions

Evaluations should be performed on both aged and unaged specimens to establish a basis of

comparison.

Commentary

The tests are intended to permit estimations to be made of the effect of solar radiation

in degrading collector components and in reducing the collector efficiency. The 1000

equivalent sun hours test time is considered to be equivalent to approximately 6 months of

actual s6lar exposure with an average exposure time of 6 hours per day.

Part B - Test Methodology: Criterion 5.1.1(b)

Method 1 involves the exposure of the collector to solar radiation at an actual test site

and measuring the decrease in collector efficiency as a result of the exposure. State-ofthe-art collector test methods are referenced in Criterion 1.3.1.

58
CHAPTER FIVE - DURABILITY / RELIABILITY

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Method 2 involves measuring the deterioration of the window(s) and the absorbant surfaces

separately by means of small scale laboratory tests and then incorporating this information

into a model developed by ASHRAE which can be used to calculate collector efficiency. The

test procedure for Method 2 is given below.

Method 1 for Evaluating the Effects of Solar Degradation on the Performance of the Collector

Test Specimens

The test specimen shall consist of either the entire collector as it would be used in

actual service or a thermally equivalent segment of the entire collector.

Aging Procedure

Expose the collector to solar radiation equivalent to that obtained by a one month exposure

in Phoenix, Arizona in July with an average exposure time of 6 hours per day normal to the

sun. For each 30 days of exposure, the collector shall be exposed one day without the

heat transfer fluid.

Test Procedure

Test the collector before and after aging for thermal efficiency. State-of-the-art test methods are referenced in Criterion 1.3.1.

The test specimens shall exhibit no significant change in performance as a result of the

aging procedure.

Method 2 for Evaluating the Effects of Solar Degradation on the Performance of the Collector

(Primarily for spectrally selective materials)

Test Specimens

Test specimens shall consist of coupon specimens of the materials to be tested.

Specimens of window materials for aging and evaluating shall consist of the number of

windows used in the collector spaced and aligned as they would be in the collector

.

Aging Procedure

Specimens shall be exposed to simulated solar radiation* with the spectral intensity in

the 300 to 450 nm wavelength range equivalent to the air mass 2 solar spectrum (such as Xenon arc radiation) for a period of 1000 hours at the maximum temperature to which they

will be subjected in actual service. The exterior surfaces of the components shall be

subjected to a water spray for a period of five minutes during each sixty minutes of the

light exposure.

Test Procedures* *

Collector Window(s)

1. Measure the total spectral transmittance (including both diffuse and normal

radiation) of the window(s) from 300 to 1820 nm.*

The specimen shall be mounted perpendicular to the incident radiation.

Other less sensitive test procedures which are directly integrating are given in

ASTM E 424 and E 434.

59
CHAPTER FIVE DURABILITY / RELIABILITY

systems and components

2. Expose the window(s) to the aging procedure described above.

3. Repeat step 1.

4. Calculate the solar transmit tance (i) determined from transmittance measurements

from 300 to 1820 nm for both unaged and aged specimens using the procedure described

under Calculations .

Absorbant Surface

Part A

1. Measure the directional reflectance of the absorbant surface in the infrared

spectral range from 3 to 20 ym (3000 - 20000 nm) .

2. Expose the absorbant surface to the aging procedure described above.

3. Repeat step 1.

4. Convert the reflectance valves to emittance (e) assuming an opaque coating where:

Emittance = 1 - Reflectance.

5. Calculate the total emittance from 3 to 20 pm for both unaged and aged specimens

using the procedure described under Calculations .

Part B

1. Measure the directional reflectance of the absorbant surface from 300 to 1820 nm.

2. Expose the absorbant surface to the aging procedure described above.

3. Repeat step 1.

4. Convert the reflectance values to absorptance assuming an opaque coating where:

Emittance = Absorptance = 1 - Reflectance.

5. Calculate the solar absorptance (a) from 300 to 1820 nm for both unaged and aged

specimens using the procedure described under Calculations .

Calculations

Transmittance

1. Multiply the measured value of transmittance of both aged and unaged window

specimens at various wavelengths from 300 to 1820 nm by the value of solar energy

(watts/cm^/nm) at the same wavelengths as read from Figure A-5.

2 2. Plot energy (watts/cm /nm) versus wavelength curves for both aged and unaged

specimens

.

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CHAPTER FIVE - DURABILITY / RELIABILITY

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CHAPTER FIVE DURABILITY / RELIABILITY

systems and components

3. Integrate, from 300 to 1820 nm, the area under the curve of Figure A-5

and record the area (Erj,.j^) .

4. Integrate, from 300 to 1820 nm, the area under the energy versus wavelength curve

for unaged specimens and record the area (Erj,2) •

5. Integrate, from 300 to 1820 nm, the area under the energy versus wavelength curve

for aged specimens and record the area (E.^.^) •

6. Divide Ej2 by Exi to obtain the solar transmittance , T2, as measured for the unaged

window specimen.

7. Divide E^s by Exi to obtain the solar transmittance , 13, as measured for the aged

window specimen.

8. Incorporate T2 and 13 into the appropriate equations used in the method to determine the collector efficiency in Criterion 1.3.1.

Total Emittance*

The total emittance of surfaces can vary with temperature because of the change in

energy spectral distribution with temperature according to the Planck Radiation Law. The influence of environmental effects on the total emittance can be determined from

spectral emittance data by the following procedure.

2 1. List the spectral emittance and the spectral energy (w/cm /ym) of a black body in

at least 0.5 ym wavelength intervals over the wavelength range of 3.0 to 20.0 ym

for each temperature. Use a maximum of 10 C (50 F) temperature intervals over

the temperature range of collector operation (nominally from 38 to 121 C (100 to 250 F) . Calculate the product of these two values for each wavelength interval.

2. Plot the data obtained from step 1 as a function of wavelength for both aged

and unaged specimens and for each temperature. Plot the spectral energy distribution for a black body for each temperature used.

3. Integrate from 3.0 to 20.0 ym, the area under the black body curve for each temperature and record the area (E^.^) •

4. Integrate, from 3.0 to 20.0 ym the area under each energy-emittance curve for unaged specimens and record the area (E^^) for each temperature.

5. Integrate, from 3.0 to 20.0 ym, the area under each energy-emittance curve for

aged specimens and record the area (E^2) each temperature.

6. Divide E^^^ by E^^ for each temperature to obtain el for each unaged specimen and

E^2 by E^g to obtain e2 for each aged specimen.

7. Incorporate el and e2 into the appropriate equations used in the method to determine collector efficiency in Criterion 1.3.1.

*Total hemispherical emittance can be determined by means of calorlmetric techniques.

Total normal emittance can be measured with a portable emissometer.

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CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Absorptar.ee

1. Multiply the value of absorptance of both aged and unaged absorbant surface

specimens at various wavelengths from 300 to 1820 nm by the value of solar energy

(watts/cm^/nm) at the same wavelengths as read from Figure A-5.

2 2. Plot energy (watts/cm /nm) versus wavelength curves for both aged and unaged

specimens

.

3. Integi'ate, from 300 to 1820 nm, the area under the curve of Figure A-5.

and record the area (E „)

.

ap

4. Integrate, from 300 to 1820 nm, the area under the energy versus wavelength curve

for unaged specimens and record the area (E^^).

5. Integrate, from 300 to 1820 nm, the area under the energy versus wavelength curve

for aged specimens and record the area (2^2^

•

6. Divide E^^ by E^^ to obtain the solar absorptance, al, for the unaged window specimen.

7. Divide E ^ by E „ to obtain the solar absorptance, a2, for the aged window specimen.

8. Incorporate al and a2 into the appropriate equations used in the method to determine collector efficiency in Criterion 1.3.1.

Transmittance or Reflectance by ASTM Method E 424

An alternate calculation method to. those presented above is presented in ASTM Method

E 424 for transmittance and reflectance. In ASTM E 424, solar energy transmittance or reflectance is calculated by integration using the solar energy distribution for sea level and air mass 2.0. Table A-1 contains ^twenty selected ordinates for use in the

calculations

.

Table A-1 Twenty Selected Ordinates

Reflectance at Sea Level*

for Evaluation of Solar Transmittance or

Ordinate

Number

Wavelength

(nm)

Ordinate

Number

Wavelength

(nm)

1 390 11 745

2 444 12 786

3 481 13 831

4 511 14 877

5 543 15 959

6 574 16 1026

7 606 17 1105

8 639 18 1228

9 669 19 1497

10 705 20 1722

*Extracted from ASTM Method E 424

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CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Section 04 - Test Methodology: Criterion 5.1.2

Testing shall be performed for a period of 500 hours, at the maximum service temperature

to which the components will be subjected in actual use. During the duration of the test coupon specimens shall be partially immersed in aqueous solutions having a pH equivalent to that found in soil specimens taken from the sites where the systems are intended to be used.

On the basis of visual observation made on the specimens both before and after immersion,

there shall be no signs of deterioration that would significantly impair their function.

Section 05 - Test Methodology: Criterion 5.1.3

This section contains test methods to determine the resistance of components • to airborne

pollutants. Following the test, specimens shall exhibit no signs of deterioration that

would significantly impair their performance.

Resistance to Ozone

Coupon specimens of components shall be exposed for 500 hours to an ozone atmosphere

of 50 ± 5 pphm/volume in a test chamber at 23 ± 2°C (73.4 ± 3.6°F). After the exposure,

the surfaces of the specimens shall be visually examined for signs of deterioration

such as cracking, blistering or dimensional changes using a microscope with an eyepiece micrometer at 20X magnification. An ozone test chamber is described in ASTM

D 1149-64 (1970), "Accelerated Ozone Cracking of Vulcanized Rubber."

The extent of change of the specimens as a result of the exposure shall be determined

by comparing the exposed specimens to control specimens or by comparing the characteristics of the same specimens before and after exposure.

Resistance to Salt Spray

Coupon specimens of components shall be evaluated in accordance with ASTM Standard

Method B 117-73. After exposure for 500 hours, the specimens shall be visually examined

for signs of deterioration such as cracking, crazing, blistering or pitting. The extent

of the change as a result of the exposure shall be determined by comparing the exposed

specimens to control specimens or by comparing the characteristics of the same specimens before and after exposure.

Resistance to SO2, NOy and HCl

Coupon specimens shall be immersed for 500 hours in aqueous solutions containing 100 ppm

of H2SO3, HNO3 and HCl on a one component per test solution basis so that one half the

specimen is in the solution. During the immersion, the temperature of the test

specimens shall be cycled repetitively as follows: one hour at the maximum service

temperature, one hour at 23 ± 2°C ^73.4 ± 3.6°F)^ one hour at the minimum service

temperature and one hour at 23 ± 2 C (73.4 ± 3.6 F) . After exposure, the specimens

shall be visually examined for signs of deterioration such as cracking, crazing,

blistering or pitting. The extent of change of the specimens as a result of the

exposure shall be determined by comparing the exposed specimens to control specimens

or by comparing the characteristics of the same specimens before and after exposure.

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systems and components

Section 06 - Test Methodology; Criterion'- 5. 2.1

Complete components or coupon specimens shall be subjected to heat aging for a period of

500 hours at the maximum service temperature to which they will be exposed in actual

service. Components and materials stressed in normal use should be stressed during the

exposure. They shall be visually inspected both before and after aging. Both aged and

unaged specimens of organic components shall also be tested for tensile strength using

ASTM D638-72.

When visually evaluated after exposure at the maximum service temperature, there shall be

no significant signs of cracking, crazing, blistering or other deterioration. Also, the

specimens shall exhibit no significant loss of strength as a result of the aging.

Section 07 - Test Methodology; Criterion 5.2.2

All heat transfer and storage fluids shall be subjected to the tests below;

Test 1 - Expose the fluids to their maximum "flow" temperature for

a period of 500 hours.

Test 2 - Expose the fluids to their minimum service temperature

for a period of 500 hours.

Test 3 - Subject the fluids to 100 cycles of cooling and heating

with each cycle consisting of the following steps:

a. Cooling to the minimum service temperature over a period of two hours.

b. Holding at the minimum service temperature for

two hours.

c. Heating to the maximum "flow" temperature over period of two hours.

d. Holding at the maximum "flow" temperature for two

hours

.

Periodically, during each test, and at the completion of each test, Inspect the fluids

visually for signs of undesired changes such as freezing, excessive precipitation, boiling

or formation of gas bubbles. Also, before and after each test, measure the pH and the

viscosity of the fluid. Boiling tests shall be conducted at service pressures. After

the tests, the fluids shall not exhibit changes that would significantly impair their

ability to function.

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CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Section 08 - Test Methodology: Criterion 5.2.3

Subject samples of each subassembly of the system, which would normally undergo thermal

cycling, to 100 cycles of cooling and heating with each cycle consisting of the following

steps:

a. Cooling to the minimum service temperature over a period of two hours.

b. Holding at the minimum service temperature for two hours.

c. Heating to the maximum service temperature over a period of two hours.

d. Holding at the maximum service temperature for two hours.

During the test, the specified minimum or maximum temperature shall be maintained only on

the collector plate so that the plate will be the heat source. The temperature of other

components shall be permitted to vary as the temperature of the plate changes.

After every third cycle and at the end of the test, visually inspect the components for

signs of thermal incompatibility.

After exposure to the repeated cycles at the maximum and minimum service temperatures,

there shall be no significant signs of cracking, crazing, loss of adhesion or other

deterioration

.

Section 09 - Test Methodology: Criterion 5.2.4

Joints and system components which contain heat transfer fluids (other than air) shall be

static pressure tested with the heat transfer fluids at a pressure equal to 150% of the

working pressure that would occur in the component. Testing shall be performed concur- rently for a period of 500 hours at the minimum service temperature and a period of 500

hours at the maximum service temperature.

During and following the pressure tests, visual inspections shall be made to identify

evidence of leaks. Also the pressure of the fluid shall be monitored to detect changes

due to leakage

.

Section' 10 - Test Methodology: Criterion 5.2.5

Subject the components to 100 cycles of soaking and drying with each cycle consisting of

the following steps:

1. Immerse the components in the heat transfer fluid at the maximum service

temperature for a period of four hours.

2. Dry the components at the maximum service temperature for four hours.

After each cycle and at the end of the test visually inspect the components for signs of

cracking, swelling or other dimensional changes or loss of adhesion to adjoining

components

.

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CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Section 11 - Test Methodology: Criterion 5.2.6

Components inside the collector shall be subjected to 100 cycles of heating and cooling

with each cycle consisting of the following steps:

a. Heating to the maximum service temperature over a period of two hours at the

rated pressure of the system.

b. Holding at the maximum service temperature for two hours.

c. Cooling to the minimum service temperature over a period of two hours at the rated pressure of the system.

d. Holding at the minimum service temperature for two hours at the rated

pressure of the system.

After every third cycle, visually inspect the underside of the collector window. If there

is visual evidence of condensation, transmittance measurements shall be conducted during

the test to determine the rate of loss in optical transmission. In addition, transmittance

measurements shall be conducted at the end of 100 cycles for every test specimen.

Section 12 - Test Methodology: Criterion 5.3.1

Coupon specimens, or entire components, shall be immersed in the heat transfer fluid for a period of 500 hours. During the immersion, the temperature of the test specimens or components shall be cycled repetitively as follows: one hour at the maximum service temperature, one hour at 23 + 2°C (73.4 + 3.6°F), one hour at the minimum service temperature and

one hour at 23 + 2°C (73.4 + 3.6°F). Protective coatings shall form a part of the test

specimen if they are used in the actual system. Testing shall be followed by visual

inspection. Standard TM-01-71, Autoclave Corrosion Testing of Metal in High Temperature

Water, of the National Association of Corrosion Engineers or ASTM D2570-73, Simulated

Service Corrosion Testing of Engine Coolants, may be used in the evaluation.

Following the test, the test specimens shall not show signs of pitting or exhibit other

signs of general corrosive deterioration with the exception of discoloration.

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CHAPTER FIVE - DURABILITY / RELIABILITY

systems and components

Section 13 - Test Methodology: Criterion 5.3.2

Non-isolated Dissimilar Materials Used in Contact with the Transfer Fluid /

Test specimens consisting of dissimilar materials in direct contact with one another shall

be immersed in the heat transfer fluid for 'a period of 500 hours at the maximum service

temperature. During the test, the heat transfer fluid shall be circulated. This shall

be followed by visual observation. Protective coatings shall be used when they form a part of the component.

Non-isolated Dissimilar Materials Not Used in Contact with the Transfer Fluid

Test specimens consisting of dissimilar materials in direct contact with one another shall

be subjected to 100 cycles of heating and cooling. Each cycle shall consist of:

a. Heating to the maximum service temperature over a period of two hours.

b. Holding at the maximum service temperature and a relative humidity of

50% or greater for two hours.

c. Cooling to the minimum service temperature over a period of two hours.

d. Holding at the minimum service temperature for two hours.

Following the exposure, visually inspect the specimens for signs of corrosion.

At the completion of the above tests, specimens shall not show signs of pitting or exhibit other signs of corrosive deterioration, with the exception of discoloratiofi.

Section 14 - Test Methodology: Criterion 5.3.3

Expose components containing leachable substances and components that may be affected by

the leachable substances in water or steam for a period of 500 hours at the maximum

service temperature. At the end of the exposure, visually inspect the component that may

have been affected by the leachable substance for signs of deterioration such as pitting,

cracking or dimensional changes.

Section 15 - Test Methodology: Criterion 5.3.4

The evaluation shall consist of two stages. In the first stage, components shall be

heated to their maximum service temperatures for two hours and the composition of the

decomposition products, if any, shall be determined. Analysis for organic materials

could be by infrared spectroscopy or chromatography. Standard wet chemical techniques

could be used for inorganic substances.

The second stage of the evaluation shall be performed if the amount and types of decomposition

products are significant. The second stage shall consist of subjecting components, that would

be exposed to the decomposition products in actual service, to the decomposition products in

a test chamber for 100 hours at the maximum service temperature of the components being

tested. The concentration of the decomposition products shall be the maximum concentration

expected in actual service. During the exposure, moisture shall be added to the test chamber

to maintain a relative humidity of 90% or greater.

After the exposure, test specimens shall be visually examined for signs of degradation such

as cracking, corrosion and swelling or other dimensional changes.

68
CHAPTER SIX - MAINTAINABILITY

systems and components

6.1 Requirement Accessibility for maintenance and servicing . The systems for heating

(H) , combined heating and cooling (HC) and the domestic hot water (DHW)

system/subsystem shall be designed, constructed, and installed to provide sufficient access for general maintenance, convenient servicing

and monitoring of system performance.

6.1.1 Criterion Access for system maintenance . All individual items of equipment and

components of the H, HC and DHW systems which may require periodic

examination, adjusting, servicing and/or maintenance shall be accessible

for inspection, service, repair, removal or replacement without dismantling of any adjoining major piece of equipment or subsystem.

Evaluation Review of drawings and specifications.

Connnentary Accessibility as a function of component life is an important consideration .

Information on access provisions is provided in Reference [1]

.

6.1.2 Criterion

Evaluation

Commentary

Access for system monitoring . Appropriate access for sensors shall be

provided for inspecting and checking essential system parameters such

as temperature, pressure and critical voltages.

Review of drawings and specifications for the location of test fittings,

Adequately located test fittings will permit system monitoring and

expedite the maintenance and repair of equipment

.

6.1.3 Criterion Draining and filling of liquids . To facilitate system or subsystem

maintenance and repair, subsystems employing liquids shall be capable

of being conveniently filled and drained.

Evaluation Review of drawings and specifications,

Commentary The potential buildup of vapor which could create air pockets and thus

block or restrict the flow of heat transfer fluids should be considered. (See Criterion 2.1.5)

6.1.4 Criterion Flushing of liquid subsystems . Suitable connections shall be provided

for the flushing (cleaning) of liquid energy transport subsystems.

Evaluation Review of drawings and specifications.

Commentary The recommendations of the system manufacturer for cleaning agents

compatible with the materials of the system should be followed.

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CHAPTER SIX - MAINTAINABILITY

systems and components

6.1.5 Criterion Filters . Filters shall be designed and located so that they can be

cleaned or replaced with minimum disruption to the system and adjacent

equipment. Cleaning frequencies shall be specified by the system

manufacturer in the maintenance manual.

Evaluation Review of drawings and specifications.

6.1.6 Criterion ^ Potable water shutoff . The DHW system shall be valved to provide

shutoff from the cold water supply.

Evaluation Review of drawings and specifications.

6.2 Requirement Installation, operation and maintenance manual . A manual shall be

provided for the installation, operation and maintenance of the H,

HC and DHW systems,

6.2.1 Criterion Installation instructions . The manual shall include physical, functional

and procedural instructions describing how the subassemblies of the H,

HC and DHW systems are to be installed.

These instructions shall include descriptions of both interconnections

between the system subassemblies and their interfaces and connections

with the dwelling and site.

Evaluation Review of installation instructions.

6.2.2 Criterion Maintenance and operation instructions . The manual shall completely

describe the H, HC and DHW systems, their breakdown into subsystems,

their relationship to external systems and elements, their performance

characteristics, and their required parts and procedures for meeting

specified capabilities.

The manual shall list all parts of the systems, by subsystem, describing as necessary for clear understanding of operation, maintenance, repair and replacement, such characteristics as shapes, dimensions, materials, weights, functions and performance characteristics.

The manual shall include a tabulation of those specific performance

requirements which are dependent upon specific maintenance procedures.

The maintenance procedures, including ordinary, preventive and minor

repairs, shall be cross-referenced for all subsystems and organized

into a maintenance cycle . The manual shall fully describe operation

procedures for all parts of the system including those required for

implementation of specified planned changes in mode of operation.

Evaluation Review of maintenaftce and operating instructions.

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CHAPTER SIX - MAINTAINABILITY

systems and components

6.2.3 Criterion Maintenance plan . The manual shall include a comprehensive plan for

maintaining the specified performance of the H, HC and DHW systems

for their design service lives.

The plan shall include all the necessary ordinary maintenance,

preventive maintenance and minor repair work and projections for

equipment replacement

.

Evaluation Review of maintenance plan.

6.2.4 Criterion Replacement parts. Parts, components, special tools and test equipment

required for service, repair or replacement shall be commercially

available or available from the system or subsystem manufacturer or supplier.

Evaluation Review of specifications for the availability of parts.

Commentary This criterion is intended to preclude long periods of system downtime due to the need for the repair or replacement of parts.

6.3 Requirement Repair and service personnel . The H, HC and DHW systems shall be

designed in such a manner that they can be conveniently repaired by

qualified service personnel.

6.3.1 Criterion Maintenance of H and HC systems . The H and HC systems shall be capable

of being serviced with a minimum amount of special equipment by a trained HVAC service technician using a maintenance manual.

Evaluation Review of drawings, specifications, and maintenance instructions.

Commentary The complexity and design of certain components may require their

removal and replacement for repair of the system.

6.3.2 Criterion Maintenance of DHW system. The DHW system shall be capable of being

serviced with a minimum amount of special equipment by a qualified

service technician using a maintenance manual.

Evaluation Review of drawings, specifications, and maintenance instructions.

71
CHAPTER SIX MAINTAINABILITY

systems and components

References

!• Uniform Mechanical Code , International Conference of Building Officials,

Whittier, California (1973).

72
dwellings

and

sites

CHAPTER SEVEN - FUNCTION

dwellings and sites

7.1 Requirement Design . The dwelling and site shall utilize materials, designs and

construction methods appropriate to the use for which they are intended

.

7.1.1 Criterion Dwelling design . One and two family dwellings and multifamily housing

shall be designed and constructed in compliance with the HUD Minimum

Property Standards (MPS) [1].

Evaluation Review of drawings and specifications.

Connnentary A well designed solar energy system which includes the building system

must not only collect solar energy but also provide for the efficient

storage, distribution and use of that energy. Therefore, solar systems

are not merely energy collecting systems, but also energy conserving

systems. The standards set in the MPS represent a minimum level of

performance. They do not completely address energy conservation and

upgrading in this area may be desirable.

There are several approaches that should be considered for the design of

buildings that conserve energy. One approach considers the site where

energy can be conserved by managing the microclimate and therefore

modifying its effect on the building. This can be done through the

application of varying degrees of factors such as:

1. Shading devices such as trees and fences

2. Windbreaks or- wind funnels

3. Reflecting surfaces such as pools, roads, sidewalks, patios, and

walls

4. Humidifiers such as pools and fountains

5 . 'Heat storage materials such as dark pavement

A second approach considers the exterior envelope of the building

where energy can be conserved by modifying factors such as:

1. Color

2. Texture

3. Orientation and slope in relation to the wind or sun

4. Shape (in order to vary air pressure, turbulence, and solar

exposure)

5. Surface area

6. Thermal conductivity

7. Opening design (size, location, aerodjmamics)

8. Weather tightness

9. Shading devices (interior and exterior)

10. Reflectivity (solar and infrared)

In a third approach, by carefully considering the mass of the building

and the objects around the building, the rate at which energy is stored

and released can be managed e.g., storing energy during the day to be released at night can reduce the thermal load on the building

in either a cooling cycle or a heating cycle depending on whether

the energy is released inside or outside.

Which combination of options is chosen and how effective the selection

will be is dependent on design conditions and design goals.

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CHAPTER SEVEN - FUNCTION

dwellings and sites

7.1.2 Criterion Mobile home design . Mobile homes shall be designed and constructed

in compliance with the_ ANSI A119.1, Standard for Mobile Homes [2].

Evaluation Review of drawings and specifications.

Commentary See Commentary: Criterion 7.1.1.

7.1.3 Criterion

Evaluation

Commentary

Site design . The sites for one and two family dwellings, multifamily

housing and mobile homes shall be designed and constructed in com- pliance with the MPS[1] and/or ANSI A119.3[3], as appropriate

.

Review of site plan and specifications.

See Commentary: Criterion 7.1.1

7.1.4 Criterion

Evaluation

Commentary

Passive use of solar energy . Consideration shall be given in the

dwelling and site design to the passive utilization of solar energy,

wherever practical.

Review of drawings and specifications.

Savings can be realized when normally provided components of the

building and site can be given an additional use in the heating (H)

,

combined heating and cooling (HC) and domestic hot water (DHW)

systems. Considering the building itself as a system for capturing

j

storing, and utilizing solar energy can provide opportunities for

reductions in the building heating or cooling requirements.

7 . 2 Requirement Adequate space . The dwelling and site shall provide space to accom- modate the H, HC and DHW systems.

7.2.1 Criterion Collector area . The dwelling and site shall provide sufficient

space to install the solar collector.

Evaluation Review of site plans and architectural drawings showing the area provided for the solar collector and calculations showing the space

needed for the collector.

7A
CHAPTER SEVEN - FUNCTION

dwellings and sites

Commentary This criterion does not require that the solar collector be

separate from other solar subsystems but only intends to establish that

adequate surface area has to be provided if the collecting element

is installed on the building or site. Establishing the slope and area

of the collector is a complicated problem and requires consideration

of factors such as the following:

1. Climatic region

2. Collector orientation and tilt angles

3. Collector exposure to wind

4. Amount of energy supplied or released by the collector

5. Collector mounting (free standing or integrated with the

building)

6. Efficiency of collector

7 • Type of auxiliary energy used

7.2.2 Criterion Storage area . Where thermal storage is required, the dwelling and/or

site shall provide sufficient space to install the storage subsystem.

Evaluation Review of architectural drawings and site plans showing the space

provided for thermal storage and calculations showing the volume

required for storage.

Commentary This criterion does not require that storage be separate from

other solar subsystems it is intended to ensure that a sufficient

volume is provided for storage.

The amount of storage required will vary with factors such as:

1. The heat capacity of the storage medium

2. Climatic region

3. Amount of energy supplied or released by the collector

4. Efficiency of the collector

5. Heat losses in the system

6. Design load of H, HC and DHW systems

7.2.3 Criterion Utility chases . When the energy transport subsystem is installed

within floors, walls, ceilings or utility chases, adequate space

shall be provided for installation.

Evaluation Review of the mechanical drawings showing the layout

of the energy transport subsystem and typical architectural sections

for walls, floors and roof.

Commentary A preferred location for piping and ducts in walls may be within

interior walls rather than in exterior walls. This is particularly

true for those pipes and ducts delivering domestic hot water, heating or cooling to thfe building so that losses and gains therefrom

will be contained within the conditioned space.

75
CHAPTER SEVEN - FUNCTION

dwellings and sites

7.3 Requirement Functioning of dwelling and site . The use of the dwelling and site

shall not be substantially impaired by the H, HC and DHW systems.

7.3.1 Criterion Space use . A location shall be provided for solar subsystems that

will not significantly impair the use of required exterior or interior spaces, as defined in the MPS[1].

Evaluation Review of site plans and architectural floor plans showing the

location of solar subsystems.

Commentary The space provided for the solar subsystems should be in addition to that required by the MPS and the location of the subsystems should

not unduly interfere with the use of a space, the required headroom

in a space, or required circulation through a space. The

system should not unduly interfere with trash removal, furniture

moving, the servicing of mechanical equipment, or the normal movement

of people and vehicles. Since a collector may reflect a large percentage of the incident solar radiation at high incident angles, the

possibility of reflecting solar rays onto areas where people congregate

should be investigated.

7.3.2 Criterion Shading of adjacent structures . The dwelling and its solar subsystems

shall not significantly infringe on the ability of adjacent dwellings

/ ". and their solar subsystems to collect solar energy or provide natural

interior light.

Evaluation Review of calculations and a site plan showing the areas of adjacent

buildings shaded on June 21 (for cooling) and December 22 (for heating)

between 10 AM and 2 PM solar time. Other days may be used if deemed

appropriate.

Commentary Data are available for calculating shading angles as a function of

the time of day and year [4] [5].

7.3.3 Criterion Impact on environment . A site location shall be provided for the

dwelling and its solar subsystems which will not significantly endanger

the natural environment.

Evaluation Review of drawings and a report on the negative effects of the building

and its solar subsystems on drainage, vegetation, microclimate and

wildlife.

76
CHAPTER SEVEN - FUNCTION

dwellings and sites

Commentary This criterion does not require that existing conditions should be

maintained but that environmental degradation should be prevented

which cannot be neutralized within a year by nature or which

could set up a chain reaction affecting a much larger area than

the individual building site. Several examples can be cited that

could cause such conditions to exist: (1) if runoff from a large

collector is not collected and carried away in a drainage system it

could for certain soil conditions cause excessive erosion; (2) if

the reflected rays from a collector or the shade created by a collector killed existing vegetation and prevented the growth of new

vegetation, large areas of soil might be exposed to excessive runoff

and if erosion resulted, it could represent a hazard to surrounding

streams; (3) the location provided for, and the installation of solar

subsystems may make it necessary to cut down trees or may kill them

after construction as a result of compaction, drying, sunburn, overturning, grade change, root pruning or other reasons.

7.3.4 Criterion View . The location of solar subsystems shall not unnecessarily block

interior or exterior views of the site, unless they are intended as an integrated part of that view.

Evaluation Review of architectural and site plans.

Commentary Even well designed subsystems can be an undesirable obstruction to views from the house or site unless they are integrated into the

view, as might be the case with a fence used as a collector.

77
CHAPTER SEVEN - FUNCTION

dwellings and sites

References

1. HUD Minimum Property Standards, One and Two Family Dwellings (No. 4900.1), U.S.

Department of Housing and Urban Development, Washington, D.C. (1973, revised

1974) and HUD Minimum Property Standards, Multifamlly Housing (No. 4910.1),

U.S. Department of Housing and Urban Development, Washington, D.C. (1973).*

2. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards

Institute, New York, N.Y. (1974).

3. Standard for Mobile Home Parks , ANSI A119. 3-1973, American National Standards

Institute, New York, N.Y. (1973).

4. Aronin, J., Climate and Architecture , pp. 27-61, Reinhold Publishing Company,

New York, N.Y. (1953) .

5. Givoni, B., Man, Climate and Architecture , pp. 185-188, Elsevier Publishing

Company, New York, N.Y. (1969).

*Available from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402.

78
CHAPTER EIGHT - MECHANICAL

dwellings and sites

8.1 Requirement Interference with mechanical operation . The dwelling and site

elements shall not prevent the proper mechanical functioning of

the H, HC and DHW systems.

8.1.1 Criterion Blockage of solar subsystems . Building and planting arrangements

shall be integrated with the installation of solar subsystems to avoid interference with their mechanical function.

Evaluation Review of mechanical drawings and site plans showing the location

of mechanical equipment, air intakes, outlet vents, vegetation, walls

and any other obstructions which might affect the operation of the H,

HC or DHW systems.

Commentary Existing vegetation and future growth of that vegetation can become

a problem in the functioning of mechanical equipment, air intakes

and vents. For example plants might block and therefore reduce the

efficiency of a fan or a compressor-condensor unit. On the other hand

vegetation can be used to advantage to reduce cooling load as a sunshade.

8.1.2 Criterion Shading of collector . The location provided for the collector shall

not be shaded for more than the specified period allowed for in the

design.

Evaluation Review of calculations or projected elevations of the collector

estimating the area of the collector shaded by mechanical equipment,

chimneys, vents, trees and other elements on June 21 (for cooling) and

December 22 (for heating) , or other appropriate days between 10 AM and

2 PM solar time.

Commentary In locating trees in order to minimize the amount of shade falling

on the collector, the designer may not be able to effectively use shade trees to improve the microclimate. Data are available for

calculating shading angles as a function of the time of day and

year[l] [2]. The possible shading of solar subsystems by snow

buildup, e.g., when the collector is mounted on a flat roof or on the ground, is also an important consideration.

8.1.3 Criterion Sensor location . A location shall be provided for interior and exterior

control sensors which will allow the detection of appropriate changes

in the system and the environment without unnecessary interference

from factors such as shade, drafts and vibrations.

Evaluation Review of architectural floor plans or electrical/mechanical drawings

showing the location and elevation of control sensing equipment. If

sensing equipment is located on the exterior of a building, exterior

elevations showing the location and elevation of control sensing equipment and site plans shall be provided.

79
CHAPTER EIGHT - MECHANICAL

dwellings and sites

8.2 Requirement Mechanical and electrical functioning of dwelling and site . The

mechanical and electrical operation of the dwelling or site shall

not be significantly affected by the H, HC and DHW systems.

8.2.1 Criterion Exhaust and venting . The location provided for solar subsystems shall

not interfere aerodynamically or physically with the venting of the

dwelling's plumbing systems or the exhaust of the dwelling's mechanical

systems to the extent that their intended function is impaired.

Evaluation Review of mechanical drawings showing the location of solar subsystems,

plumbing vents and mechanical exhausts.

Commentary The wind conditions created around chimneys, flues, plumbing vents,

mechanical exhausts and condensers by the presence of solar sub-

• systems should be examined for possible interference with the

mechanical operation of such elements.

,2.2 Criterion Utilities . The location and installation of solar subsystems shall

not interfere with the safe operation of existing or proposed utility

systems.

Evaluation Review of utility plan and site plan.

Commentary Underground potable water piping serving an array of solar collectors

installed remote from the building could transmit pollution from

sewerage system to the potable water system. A horizontal separation

of at least 10 feet from a septic tank drainage field and 12 inches

from a sewer line is common practice for pipes carrying potable water.

8.3 Requirement Mechanical and electrical functioning of connections . The connections

between the H, HC, and DHW systems and the dwelling or site shall

function mechanically or electrically as intended.

,3.1 Criterion Plumbing connections. Plumbing connections between the solar subsystems and water service or waste disposal systems shall be

in accordance with the MPS[3] or ANSI A119.1[4], as applicable.

Evaluation Review of mechanical drawings and any details or specifications

related to plumbing connections.

Commentary Particular attention should be given to making sure that plumbing

connections are dimensionally coordinated, that pipe sizes and

threads are compatible, and that changes in direction do not unduly

restrict the flow of fluid.

80
CHAPTER EIGHT - MECHANICAL

dwellings and sites

,3.2 Criterion Electrical connections . Electrical connections between the solar

subsystems and the electrical system of the dwelling or electrical

service to the dwelling shall be in accordance with the MPS [3 ] or ANSI A119.1[4], as applicable.

Evaluation Review of electrical/mechanical drawings and details or specifications

related to electrical connections.

Commentary Particular attention should be given to making sure that electrical

connections do not overload the electrical service and that electrical

connections are mechanically secure and do not create a fire hazard.

SI
CHAPTER EIGHT - MECHANICAL

dwellings and sites

References

1. Aronin, J., Climate and Architecture , pp. 27-61, Reinhold Publishing Company,

New York, N.Y. (1953)

.

2. Givoni, B., Man, Climate and Architecture , pp. 185-188, Elsevier Publishing

Company, New York, N.Y. (1969).

3. HUD Minimum Property Standards , One and Two Family Dwellings (No. 4900.1),

U.S. Department of Housing and Urban Development, Washington, D.C.* (1973,

revised 1974) and HUD Minimum Property Standards, Multlfamily Housing (No.

4910.1), U.S. Department of Housing and Urban Development, Washington,

D.C.* (1973).

4. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards

Institute, New York, N.Y. (1974).

*Available from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

82
CHAPTER NINE - STRUCTURAL

dwellings and sites

9.1 Requirement Structural integrity of H, HC and DHW systems . The dwelling or site

shall not unduly affect the structural integrity of the H, HC and

DHW systems.

9.1.1 Criterion Movement in adjacent structures . The locations provided for the

installation of solar subsystems shall take into account possible

movements in adjacent structures which could cause damage.

Evaluation Review of site plans and structural drawings.

Commentary The possibility of stresses being imposed by thermal expansion or contraction, wind movements or foundation settlement of adjacent

structures should be considered.

9 . 2 Requirement Structural integrity of dwelling , xhe structural integrity of dwelling and site elements shall not be unduly affected by the H, HC and

DHW systems.

9.2.1 Criterion Loads . In addition to basic design loads, dwelling and site elements

shall be capable of carrying the increased loads imposed by solar

subsystems.

Evaluation Review of structural drawines, specifications and design calculations

taking into consideration the loads set forth in Chapter 3, Structural,

Systems and Components

.

9.2.2 Criterion

Evaluation

Commentary

Penetration of structural members . Penetrations in structural elements

required for installing solar subsystems shall be located where they

will not reduce the strength of structural members below allowable

design values.

Review of structural and mechanical drawings.

This criterion is intended to prevent holes which are cut for the

installation of pipes, ducts, conduit wires and other mechanical

equipment from reducing the required strength of structural members.

83
CHAPTER NINE - STRUCTURAL

dwellings and sites

9.3 Requirement Structural connections . Structural connections between solar

subsystems and the dwelling or site elements shall be capable of

carrying imp.osed loads.

9.3.1 Criterion Structural connections . Structural connections between solar

subsystems and the dwelling or site elements shall be capable of

transmitting sustained loads as specified in the design.

Evaluation Review of structural drawings showing connection details, specifications and design calculations.

Commentary This criterion deals not only with the connection of major

structural elements but with brackets or other supports used

for mounting solar subsystems on a building.

9.3.2 Criterion Brittle subsystems . Large brittle elements of the solar subsy.stems

shall be attached by devices or materials capable of accommodating

the maximum movement that would occur in normal use.

Evaluation Review of structural connection details and specifications.

9.3.3 Criterion Strength and stiffness . When solar subsystems are mounted on dwelling or site elements, the structural supporting elements shall

be of sufficient strength and stiffness to accept the loads imposed.

Evaluation Review of structural details and calculations.

Commentary This criterion is intended to ensure that the local area around the

connection of a solar subsystem is structurally designed. Criterion

9.2.1 is intended to insure that those loads are carried by the

building and its footings.

84
CHAPTER TEN - SAFETY

dwellings and sites

10.1 Requirement Safety of dwelling and site . The safe operation of the dwelling or site shall not be affected by the H, HC and DHW systems.

10.1.1 Criterion Fire . The location of solar subsystems shall not be detrimental to

the fire safety of the dwelling or site.

Evaluation Review of site plans and architectural, structural, mechanical and

electrical drawings for compliance with applicable fire safety

practices as described in the HUD MPS[1] and ANSI A119.1[2].

Commentary When solar subsystems are located on the site, circulation paths

should be checked to see that interference with the movement of

fire fighting equipment or with the emergency evacuation of a building is minimized. When system components are mounted on the

building or made an integral part of the building, the fire safety

of the building's occupants must be maintained. Traditionally,

fire fighters have used the roofs of buildings for gaining access, venting and rescuing people from fires.

10,1.2 Criterion Accidents . The location provided for solar subsystems shall hot

increase the accident potential to a greater extent than would be

expected for a conventional non-solar house.

Evaluation Review of architectural plans and site plans showing the location of

solar subsystems and mechanical drawing details of the solar subsystems,

Commentary Several examples can be given of how the presence of solar subsystems

might increase accident potential: (1) Snow and ice accumulations

on the collector could present a hazard to pedestrians below, (2)

reflected rays from the collector could be distracting to drivers on adjacent highways or annoying to the occupants of nearby buildings, and

(3) the ground around a storage unit might settle, creating a hazard

because of the uneven ground

.

85
CHAPTER TEN - SAFETY

dwellings and sites

References

1. HUD Minimum Property Standards, One and Two Family Dwellings (No. 4900.1),

U.S. Department of Housing and Urban Development, Washington, D.C.* (1973,

revised 1974) and HUD Minimum Property Standards, Multifamily Housing (No.

4910.1), U.S. Department of Housing and Urban Development, Washington,

D.C.* (1973).

2. Standard for Mobile Homes , ANSI A119. 1-1974, American National Standards

Institute, New York, N.Y. (1974).

*Available from Superintendent of Documents, U.S. Government Printing Office,

Washington, D.C. 20402

86
CHAPTER ELEVEN - DURABILITY / RELIABILITY

dwellings and sites

11.1 Requirement Durability and reliability of H, HC and DHW systems . The dwelling

and site shall not reduce the durability or reliability of the H, HC

and DHW systems to an extent that would significantly impair their

intended function.

11.1.1 Criterion Vegetation . In locating plants, consideration shall be given to the

effects that their sap, roots, or growth could have on the durability

and reliability of the H, HC and DHW systems.

Evaluation Review of site plans showing the location of existing and proposed

plants and the location of the solar subsystems

.

11.2 Requirement Durability and reliability of dwelling and site . The durability or reliability of the dwelling system and site elements shall not be

reduced by the H, HC and DHW systems to an extent that would significantly impair their intended function.

11.2.1 Criterion Chemical corrosion . Solar subsystems shall not cause chemical

corrosion of the building or site elements to an extent that would

significantly impair their intended performance.

Eva'luation See Evaluation: Criteria 5.3.3 and 5.3.4 in Chapter Five, Systems

and Components

.

11.2.2 Criterion Heat and moisture . Roof mounted solar subsystems shall not cause a buildup of heat or moisture that would cause excessive deterioration

of the roofing system or other components of the dwelling.

Evaluation Review of architectural plans, specifications and calculations for

temperature buildup caused by solar subsystems.

Commentary The presence of the collector can cause abnormal heat rises which

could cause thermal degradation and the buildup of moisture which

could cause rotting.

11.2.3 Criterion Exterior penetrations . Openings in the dwelling through which piping,

ducting and/or wiring are passed shall be made watertight.

Evaluation Review of architectural details and specifications for penetrations

through the exterior walls and roof.

87
CHAPTER ELEVEN - DURABILITY / RELIABILITY

dwellings and sites

11,3 Requirement

11.3.1 Criterion

Evaluation

Durability and reliability of connections . The connections between

the H, HC and DHW systems and the dwelling that are exposed to external environmental factors shall not undergo changes that will

impair their functions.

Material compatibility . Connector materials shall be chemically and

physically compatible under in-use conditions.

See Evaluation: Criterion 5.3.2 in Chapter Five, Systems and

Components

.

88
CHAPTER TWELVE - MAINTAINABILITY

dwellings and sites

12.1 Requirement Maintainability of H, HC and DHW systems . The dwelling or site shall

not prevent- the practical maintainability of the H, HC and DHW

systems

.

12.1.1 Criterion Accessibility . Solar subsystems shall be accessible for maintenance.

Evaluation Review of site plans and architectural drawings.

Connnentary Solar subsystems should be accessible without trespassing on adjoining

property and should not be located unnecessarily under buildings or roads, behind mechanical equipment or in other places which are difficult to reach for maintenance. The energy transport system should be

accessible for maintenance without disassembling any major structural

or mechanical elements. There should be sufficient room around com- ponents to permit their examination, adjusting, servicing and/or

maintenance. Accessibility for repair and maintenance should reflect

the expected life of the component and frequency of routine maintenance

required. An element with a shorter maintenance cycle or life expectancy

should be more accessible than one that has a longer maintenance cycle

or life expectancy.

12.1.2 Criterion Misuse . Solar subsystems shall be located where the potential for

their misuse is minimized.

Evaluation Review of site plans showing the location of recreational facilities,

protective screening, roads, sidewalks, and solar subsystems.

Commentary The proximity of solar subsystems to playgrounds and sidewalks should

be examined to minimize the potential for misuse or vandalism. In addition, equipment which should only be adjusted by skilled personnel

should not be located in areas subjected to normal pedestrian traffic.

12,1.3 Criterion Permanent maintenance accessories . Permanent maintenance accessories

such as hose bibs, drains and ladder supports necessary for the

maintenance of the H, HC and DHW systems shall be provided.

Evaluation Review of maintenance plans and architectural drawings showing the

lo cation of drains, ladder supports and other permanent maintenance

accessories

.

Commentary The area around solar subsystems should be provided with necessary

drains, hose bibs and surfaces for supporting ladders or other

equipment that might be needed to service the solar subsystems.

89
CHAPTER TWELVE - MAINTAINABILITY

dwellings and sites

12.2 Requirement Maintainability of dwelling and site . The practical maintainability

of the dwelling or site shall not be significantly impaired by the

H,< HC and DHW systems.

12.2.1 Criterion Accessibility . The location of the solar subsystems shall not impair

accessibility needed to maintain the dwelling or site.

Evaluation Review of maintenance plans, site plans and architectural and

.-•i^ mechanical drawings.

Commentary The location of the underground elements should be examined both to insure that they can be maintained without trespassing on adjoining

property arid to insure that they do not prevent digging, truck access,

etc. , necessary to maintain the building or site.

12.2.2 Criterion Ice dams . The presence of a solar subsystem shall not create the

potential for significant ice damming which might cause roof leakage.

Evaluation Review of architectural roof plan and details for roof- installed

solar components

.

Commentary Ice sliding off a collector, for example, can create a dam behind

which water could accumulate and cause roof leakage.

12.3 Requirement Connections . The connections between the H, HC and DHW systems and

the dwelling or site shall be maintainable.

12.3.1 Criterion Accessibility . Connections which require maintenance shall he. accessible without disassembling major portions of the solar

subsystems, the dwelling or the site elements.

Evaluation Review of maintenance plans and mechanical, electrical and

structural connection details and specifications.

90
CHAPTER THIRTEEN - VISUAL CHARACTERISTICS

dwellings and sites

13.1 Requirement Visual characterjsterics of dwelling and site . Consideration shall

be given to the effects on the visual characteristics of the existing

and proposed environment caused by the installation of a solar dwelling.

13.1.1 Criterion Dwelling . The effects of the solar subsystems on the mass, scale,

grid pattern, texture and color of the building shall be considered.

Evaluation Review of site plans and architectural plans, elevations, models and

renderings of the building and its solar subsystems.

13.1.2 Criterion Neighborhood . Consideration shall be given to the relationship

between solar dwellings and the surrounding neighborhood.

Evaluation Review of site plans, elevations, photographs of neighboring buildings,

models and renderings of the building, its surrounding neighborhood

and solar subsystems

.

91
Glossary*

Absorptance - The ratio of the amount of radiation absorbed by a surface to the amount

of radiation incident upon it.

Absorptivity - The capacity of a material to absorb radiant energy.

Air chamber - A closed section of pipe or a container filled with air entrapped at atmospheric pressure which when mounted in a water supply line absorbs the pressure

surges caused by the rapid opening and closing of valves.

Air gap separation - The unobstructed vertical distance through the free atmosphere

between the lowest opening from any pipe or faucet supplying water to a tank, plumbing

fixture, or other device and the flood level rim of the receptacle.

Auxiliary energy subsystem - Equipment utilizing conventional energy sources both to supplement the output provided by the solar energy system as required by the design

conditions, and to provide full energy backup requirements during periods when the

solar H, HC or DHW systems are inoperable.

Back pressure - A form of backflow caused by a pump, elevated tank, boiler, or other means that could create pressure within the system greater than the supply pressure of

a fluid.

Backflow - The reverse flow of liquids, gases, or substances into the distributing pipe

lines of a potable supply of water. Backflow may occur under two conditions - pressure

greater than atmospheric (see "Back pressure") , and pressure that is sub atmospheric

(see "Backsiphonage")

.

Backsiphonage - A form of backflow due to a negative or sub atmospheric pressure.

Cathodic protection - The process of providing corrosion protection against electrolytic reactions that could be deleterious to the performance of the protected material

or component.

Chemical compatibility - The ability of materials and components in contact with each

other to resist mutual chemical degradation, such as that caused by electrolytic action

or plasticizer migration.

Climate - The prevailing or average weather conditions of a geographic area or region

as shown by temperature and meteorological changes over a period of years.

Collector efficiency (instantaneous) - The amount of energy removed by the transfer

fluid per unit of aperture (entrance window area) over a 15-minute period divided by

the total incident solar radiation onto the same collector area for the 15-minute period.

Collector subsystem - The assembly used for absorbing solar radiation, converting it

into useful thermal energy, and transferring the thermal energy to a heat transfer

fluid.

Additional definitions can be found in the HUD Minimum Property Standards (4900.1 and

+910.1)

92
Components - The lowest identifiable elements of a solar heating or heating and

cooling subsystem, such as valves, piping, controls, containers, etc.

Control subsystem - That assembly of device:

hydraulic auxiliaries used to regulate the ] storing and utilizing energy in response to

of the building occupants.

Cooling degree days - The number of degrees

65 degrees F.

Creep - A time-dependent deformation caused

Cross-connection - Any connection between a or system through which backflow can occur.

Cyclic load - A service load whose magnitudi

dependent variation.

Dead-weight tester - A standard device used

> and their electrical, pneumatic or

irocesses of collecting, transporting,

the thermal, safety, and health requirement

that the daily mean temperature is above

by sustained loads. (See "Sustained load."

potable water system and nonpotable source

(See "Backflow.")

: and/or direction are subject to timefor calibrating gages.

Design life - The period of time during which an H, HC and/or DHW system is expected

to perform its intended function without requiring major maintenance or replacement.

Dielectric fitting - An insulating or nonconducting fitting used to isolate electrochemically dissimilar materials.

Domestic hot water (DHVJ) system - The complete assembly of subsystems and components

necessary to convert solar energy into thermal energy and use this energy in com- bination with auxiliary energy, where required, to provide hot water in the building.

Ease of ignition - The flame exposure time required to produce sustained flaming of a representative specimen of material from a controlled impinging flame source.

Electrical distribution siAsystem - All electrical conductors and equipment installed

in the H, HC, and/or DHW systems, including supply conductors for operation of the

systems

.

Emittance - The ratio of the radiant energy emitted by a body to the. energy emitted by

a black body at the same temperature.

Energy transport subsystem - Those portions of the H, HC or DHW systems which transport

energy throughout the system.

Environmental impact statement - A report of any effects that the system component or building could have on the site and its surroundings.

Expansive soil - A soil which exhibits an increase in volume with an increase in

moisture content.

Failure (structural) - Failure of a structure or any structural element is defined as one of the following

(a) Sudden, locally-increased curvature, major spalling, or structural collapse.

(b) The inability of the structure to resist a further increase in load.

(c) An increase in deflection of no less than the maximum allowable deflection under

service load conditions , occurring during any 10-minute period after application

of the superimposed load without an increase in the applied load.

93
Fluid requiring special handling - Fluid having a degree of toxicity such that it is

categorized as a "highly toxic substance" or a "toxic substance" as defined by paragraphs 191.1(e) and (f) of the Hazardous Substances Act, Regulations, Part 191,

Chapter I, Title 21 [A]; fluid having a degree of flammability such that it is categorized as a "flammable" substance" or an "extremely flammable substance" as defined

by application of the Tagliabue Open-Cup Flash Point Test (stated in the Act).

Heat actuated cooling - The use of thermal energy to initiate a thermodynamic cycle

which results in lowering the temperature of a heat transfer fluid, which in turn is

used to lower the indoor air temperature.

Heat capacity - The amount of heat necessary to raise the temperature of a given mass

one degree.

Heat transfer medium - A fluid used in the transport of thermal energy.

Heating degree days - The number of degrees that the daily mean temperature is below

65 degrees F.

Heating (H) system - The complete assembly of subsystems and components necessary to convert solar energy into thermal energy and use this energy in combination with

auxiliary energy, where required, for heating purposes.

Heating and cooling (HC) system - The complete assembly of subsystems and components

necessary to convert solar energy into thermal energy and use this energy in combination with auxiliary energy, where required, for combined heating and cooling purposes.

Humidity, relative - The ratio of the mol fraction of water vapor to the mol fraction

of water vapor present in saturated air at the same temperature and barometric pressure.

In-service conditions - The conditions to which a solar heating and cooling system and

its components will be exposed during their operational lifetimes.

Integral system - A dwelling design into which a solar heating or combined solar heating

and cooling system has been integrated into the building.

Load factors - Multipliers by which design loads are increased in order to obtain the

loads to be used in ultimate strength design of structural elements.

Maximum "flow" temperature - The maximum temperature that will be obtained in a component when the heat transfer fluid is flowing through the system.

Maximum "no-flow" temperature - The maximum temperature that will be obtained in a component when the heat transfer fluid is not flowing through the system.

Maximum service temperature - The maximum temperature to which a component will be

exposed in actual service, either with or without the flow of heat transfer fluid.

Metastable precipitation - The precipitation of solid matter from a solution where

such precipitation would not normally be expected.

Minimum service temperature - The minimum temperature to which a component will be

exposed in actual service, either with or without the flow of heat transfer fluid.

9h
Mobile home - A structure, transportable in one or more sections, which is eight

feet or more in width and is thirty-two feet or more in length, and which is built

on a permanent chassis and designed to be used as a dwelling with or without a permanent foundation when connected to the required utilities.

Multi-family low rise dwelling - A residential multiple dwelling not exceeding four

stories in height with or without elevator service. (See MPS for determination of

stories .

)

Multi-family high rise dwelling - A residential multiple dwelling exceeding four

stories in height with -or without elevator service. (See MPS for determination of

number of stories.)

Operating energy - The conventional energy required to operate the H, HC and DHW

systems, excluding the auxiliary energy which supplements the solar energy collected

by the systems (e.g. the electrical energy required to operate the energy transport

and control subsystems.)

Out gas sing - The process by which materials and components expel gases.

Passive solar energy. That contribution to the building's heating and/or cooling

needs which does not require external energy other than solar or the operation of

the equipment included in the H or HC systems.

Pipe friction - Pipe wall roughness or duct wall roughness. Such roughness causes the

loss of energy in the form of heat.

Pitting - The process by which localized wear is caused in materials or components by

erosion or chemical decomposition.

Plasticizer migration - The process by which plasticizers used in plastics migrate

within the specimen and either concentrate in a narrow boundary area or migrate to another material in connection with the specimen.

Ponding - The retention of water due to deflection of horizontal surfaces.

Potential heat - The difference between the heat of combustion of a representative

specimen of material and the heat of combustion of any. residue remaining after exposure

to a simulated standard fire, determined by combustion calorimetric techniques.

pphm - Parts per hundred million.

Protective shafts - Vertical enclosures constructed of materials of the level of fire

resistiveness required for the occupancy type as provided in the MPS.

Rate of heat release - A method of measuring the relative combustibility of materials

by determining the rate at which heat is released by the material, as determined by

calorimetric techniques.

Residual deflection - The portion of the displacement of an element in a structure

which is not recovered after the removal of the action causing that displacement.

Resultant velocity of hail - The velocity resulting from a hailstone falling at its

terminal velocity and acted on by a wind force.

95
Sensors - Devices (such as pressure transducers, thermocouples, flowmeters, etc.) used

to sense individual parameters

.

Service loads -Loads which are expected during the service life of a structure and

upon which the design of the structure is based.

Shading angles - Angles that the sun makes in both elevation and azimuth that cause shadows . -

Single family dwelling - A residential building which may be either a detached,

semi-detached, duplex or row house.

Solar degradation - The process by which exposure to sunlight deteriorates the

properties of materials and components.

Solar energy - The photon energy originating from the sun's radiation in the

wavelength region from 0.3 to 2.7 micrometers.

Solar time - The hours of the day as reckoned by the apparent position of the sun. Solar noon is that instant on any day at which the sun reaches its maximum altitude

for that day.

Storage subsystem - The assembly used for storing thermal energy so that it can be

used when required.

Subsystem - One of the several major elements of a solar heating or combined heating

and cooling system, such as collectors, thermal storage devices, heaters, etc.

System — The complete assembly necessary to supply heating or combined heating and

cooling to the dwelling in which it is installed.

Sustained load - A load that is sustained over a period of time.

Tap temperature - The temperature at which fluid such as hot water is discharged from

an outlet at the point of use.

Temperature , dry-bulb - The temperature of a gas or mixture of gases indicated by an accurate thermometer after correction for radiation.

Temperature, wet bulb - The temperature at which liquid or solid water, by evaporating

into air, can bring the air to saturation adiabatically at the same temperature.

Terminal velocity of hail - The maximum vertical velocity reached by a hailstone,

occurring when the drag force on the hailstone is equal to the force exerted by gravity

on its mass.

Toxic fluids - Gases or liquids which are poisonous, irritating and/or suffocating, as classified in the Hazardous Substances Act, Part 191, Chapter I, Title 21.

Transmittance - The ratio of the radiant flux transmitted through and emerging from

a body to the total flux incident on it.

96
Ultimate strength design - A method of proportioning structures or members for failure

at a specified multiple of working loads, and assuming nonlinear distribution of

flexural stresses.

Utility plan - A drawing showing location of electrical lines, gas lines, water, etc.

Vertical penetrations - The vertical passage of a utility chase, pipe, duct, etc.,

through a fire-rated structural assembly.

Water hammer - A term-used to indicate that destructive forces, exemplified by the

pressure surges and attendant pounding noises and vibration which develop in a pipe

system when a column of noncompresslble liquid flowing through a pipe line at a given

pressure and velocity is stopped abruptly.

Water hammer arrester - A manufactured device, other than an air chamber, containing a permanently sealed cushion of gas or air, designed to provide protection against

excessive shock pressure without maintenance.

Working stress design - A method of proportioning structures or members for prescribed

working loads at stresses well below the ultimate, and assuming linear distribution

of flexural stresses.

Zero hardness - A property of softened water such that no calcium or magnesium can be

detected using ordinary analytical methods.

2 1/2 percent design summer temperature - The outdoor air temperature will be higher

than the stated value for not more than 73 hours per year (2 1/2% of the 2,928 hours

in June through September)

.

97 1/2 percent winter design temperature - The outdoor air temperature will be lower

than the stated values for not more than 54 hours per year (2 1/2% of the 2,160 hours

in December, January and February).

97
Index

Term Page Number

abrasive wear 47 airborne pollutants, effects of 46

auxiliary energy

accessibility for maintenance 59 89 chemical corrosion, effects of on dwelling and site 50,87

design cooling loads 7 design heat loads 7 electrical connections, functioning of.. ; 37,81

independence of operation, degree of 2,4

interference with mechanical operation 79 interference with utility systems 30

materials compatibility 88

penetration of structural members 29,83

plumbing connections, functioning of 37,80

vegetation, effects of 87

building design

accessibility for maintenance 90

brittle components, mounting of 84

chemical corrosion, effects of solar subsystems 87 compliance with ANSI A119.1 74 compliance with MPS 73

electrical connections, functioning of 81

loads imposed by solar subsystems 84

materials compatibility 88

passive use of solar energy 74 penetration of structural members 83

penetrations through building exterior 87

plumbing connections, functioning of 80

space for collector 74 space for energy transport subsystem 75 space for storage subsystem 75 structural connections 84 use of essential space 76

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Term Page Number

chemical compatibility of components 49

corrosion by leachable substances 50

corrosion of dissimilar materials 50

decomposition products, effects of r 51

materials/transfer fluid compatibility 49

collector

abrasive wear 47 accessibility for maintenance 69,89

availability of parts for maintenance 71 blockage of solar radiation 79

chemical corrosion, effects on dwelling and site 87 constraint loads 31

corrosion by airborne pollutants 46

corrosion by leachable substances 50

corrosion of dissimilar materials 50 cover plates, installation of 28

cyclic loads for structural elements 28

cyclic thermal degradation 48

effects of heat losses 6 efficiency/output 4 electrical connections, functioning of 37,81

equipment flow rates 11,12

equipment operating pressures 11 equipment operating temperatures 11 exhaust and venting, interference with 80

glazing materials 28

hail impact resistance 30

heat and moisture, buildup of 87 heat transfer fluid, corrosion by 49

insulation of hot surfaces 42

interference with utility systems 80

leakage prevention 15 loads imposed by 84

location to minimize damage and misuse 89

maintenance instructions 70 maintenance plan 71

maintenance skills required 71

materials compatibility 49,88

mechanical stresses 13

mold and mildew, growth of.... 41

99
Term Page Number

collector (Cont.)

movement in adjacent structures, effects of 83

mutual shadowing , 16 orientation and tilt 16

penetrations through building exterior 87 plumbing connections, functioning of 37,80

protection of potable water 40

shading of adjacent structures 76 shading of 79 solar degradation 45 space for 74 strength and stiffness of supporting elements 84 structural connections, performance of 84 structural loads , 21 thermal degradation 47 use of essential space, interference with 76 vegetation, effects of 87 condensate removal, provision for 13

connections, accessibility for maintenance 90

constraint loads 31

foundation settlement, contraction and expansion 31

controls

accessibility for maintenance 69

automation of 6 availability of parts for maintenance 71 code compliance 37 corrosion of dissimilar materials 50

electrical connections 81

electrical equipment and installation (safety) 37 equipment flow rates 11 equipment operating pressures 11

equipment operating temperatureis 11

fail-safe design 37 heat transfer fluid, corrosion by 49

hot water temperature 7 inhabited space temperature 7 installation and maintenance 6 location of control sensors 79

100
Term Page Number

controls (Cont .

)

maintenance Instructions 70 maintenance skills required 71 manual adjustment 6 plumbing equipment and installation (safety) 37 pressure relief 18,38 sensor location 79 thermal degradation 47 water contamination 41 wear and fatigue 51

corrosion - airborne pollutants 46

by heat transfer fluid 49 dissimilar materials 50

leachable substances 50

soil 45

creep and residual deflection limitations 30

cutting of structural members 29,83

cyclic loads, deflection limitations 28

damage control 28

glazing design 28

resistance to damage 28

dead loads (structural) 21 degradation

airborne pollutants 46

solar ^5

thermal 47 design (dwellings and sites) 73 dwelling design 73 mobile home design 74 passive use of solar energy 74 site design 74 DHW system/subsystem performance 3 draw and temperature design output 3 solar contribution 3 storage design capacity 3 dissimilar materials, corrosion of 50

durability and reliability of connections 88

101
Term Page Number

durability and reliability of dwellings and sites _ 87 chemical corrosion 87 exterior penetrations 87 heat and moisture buildup 87 durability and reliability of H, HC and DHW systems 45-51,87

ease of maintenance 69,89,90

effects of external environment 45

abrasive wear 47 airborne pollutants 46

dirt retention on cover plate surface 46

fluttering by wind 47 moisture degradation 45,50

soil corrosion 45

solar degradation 45

efficiency/output (systems and components) 1,3,4,5,7

electrical equipment and installation, applicable codes and standards. 37 emergency egress 40

emergency shut-off valves and switches 40

energy transport

accessibility for maintenance 69,89

availability of parts for maintenance 71 brittle components, mounting of 84 chemical corrosion, effects on dwelling and site 87 code compliance (electrical and plumbing equipment) 37 corrosion by airborne pollutants 46

corrosion of dissimilar materials 50

cyclic thermal degradation 48

electrical equipment and installation (safety) 37 equipment operating pressures 11 equipment operating temperatures 11 exhaust and venting, functioning of 80

flow rates in equipment 11 fluid expansion in equipment 12 heat transfer fluid, corrosion by 49

heat transfer fluid quality 16 impact on environment 76 insulation of hot surfaces ^2

interference with utility systems 80

102
Term Page Number

energy transport (Cont.)

isolation for maintenance 16 leakage prevention 15 loads imposed by 84

location to minimize damage and misuse 89 long term pressure and temperature performance 48

maintenance instructions 70

maintenance plan 70

maintenance skills required 71 material compatibility,. ^ 88

mechanical stresses 13

mold and mildew, growth of 41

movement in adjacent structures, effects of 83

penetration of structural members 29,83

penetrations through building exterior 87 plumbing connections, functioning of 80

plumbing installation (safety) 37 pressure relief 18

removal of condensate 'in equipment 13

removal of entrapped air 12 soil corrosion 45 solar degradation 45

space for 75 structural loads 21 use of essential space, interference with 76 vegetation, effects of 87 water -contamination i ^1

equipment design

condensate removal 13

flow rates 11 fluid expansion, provision for 12 operating pressures 11 operating temperatures 11 removal of entrapped air 12 excessive surface temperatures, protection from 42

103
Term Page Number

fail-safe controls 37 automatic pressure relief valves - 38

system failure protection 38

failure loads (structural) 23

extreme load combinations and load capacity 26 ice loads 23 vehicular loads 25 fatigue of moving parts . 51

fire-rated construction 38 fire safety 38 applicable codes and standards 38 penetrations through fire-rated assemblies 39 flammable fluids, safety provisions for 39 flow rates, equipment design for 11,12

fluid expansion, provision for in design 12

frangible materials 28>84

functioning of buildings and sites 76 impact on environment 76 shading of adjacent structures 76 space use, impairment of 76 view, impairment of 77 glazing materials 28,84 H and HC system performance 1 cooling design temperatures 1 heating design temperatures 1 independence of operation 2 relative humidity and water vapor pressure 2 solar contribution 2 habitability of occupied spaces (heat or humidity transfer effects)... 5 hail resistance (hail size and loading) 30,31

heat losses, effects of 6 heat transfer fluid, corrosion by ^9

heat transfer fluid quality 16 air quality 17 fluid treatment 17 freezing protection.., 17 liquid quality 17 hot surfaces, insulation of 42

loh
Term Page Number

interference with mechanical operation 79 blockage of solar components 79 sensor location 79

shading of collectors 79 isolation for maintenance 16

landscaping

vegetation, effects of on system 87 leachable substances 50

leakage prevention.., 15

pressure test: air transport systems 15

pressure test: nonpotable fluids 15 pressure test: potable water 15

loads

constraint 31

cyclic 28

dead 21 hail 31

live 21

maintainability of dwellings and sites 90

accessibility, provision for 90

ice dams, prevention of 90

maintainability of H, HC and DHW systems 69,70,71,89

accessibility, provision of 69,89

availability of parts 71 manual, provision of 70

misuse, location to minimize 89 permanent maintenance accessories, provision of 89

maintenance and servicing 69 access for system maintenance 69,89 access for system monitoring 69

draining and filling of liquids. 69

filters 70

flushing of liquid subsystems 70

potable water shut-off 70

105
Term Page Number

mechanical and electrical functioning of connections 80

electrical connections, applicable codes and standards 37,81

plumbing connections, applicable codes and standards 37,80

mechanical and electrical functioning of dwelling and site 80

exhaust and venting, impairment of 80

utilities, interference with. 80

mechanical stresses 13

flexible joints 14 thermal changes 14 vacuum relief protection 14 vibration from moving parts 13

vibration stress levels 13

water hammer 14 moisture degradation 45,50

mold and mildew, growth of 41

operating pressures in equipment H

operating temperatures in equipment H

output/efficiency (systems and components) 1,3,4,5,7

parts availability 71 piping supports, applicable codes and standards 18,37

plumbing equipment and installation, applicable codes and standards... 37 ponding conditions, design provisions 34 potable water, protection of 40

backflow prevention 41

contamination by materials 40

growth of fungi 41

separation of circulation loops 41

pressure relief valves and vents, provision of 18,38

repair and service personnel 71 servicing of DHW system 71 servicing of H/HC systems 71 safety of dwelling and site 85 accident potential, effects of solar subsystems 85 fire safety, effects of solar subsystems on.. 85

10 6
Term Page Number

safety provisions

code compliance 37 electrical equipment 37 emergency egress 40

fail-safe design 37 fire rated construction 38

hot surface insulation 42

identification of emergency shut-off s 40

mold and mildew^ growth of 41

pressure relief 18,38

protection of potable water and circulated air.... 40

toxic and flammable fluids 39 service loads 21

site selection and design

blockage of mechanical equipment 79

compliance with ANSI A119.3 74 compliance with MPS 74 impact oil environment 76 location to minimize damage and misuse 89

movement in adjacent structures 83

passive use of solar energy 74 shading of collector 79 vegetation, effects of on system 87 soil corrosion ^5

solar contribution, determination of 2,3

solar degradation 45

space requirements for solar equipment 74 collector, installation space required 74 energy transport, installation space required 75 thermal storage, installation space required 75 stresses, mechanical I3

107
Term Page Number

structural connections, load bearing capability of 23,26,84

brittle components, accommodation of movement 28,84

strength and stiffness requirements 29,34,84

sustained load performance of 84

structural design basis 21 service loads 21 structural integrity of buildings 83

loads imposed by solar subsystems, design for 83

penetration of structural members 83

structural integrity of H, HC and DHW systems 21-35,83

movement in adjacent structures, effects of. , 34,83

subsystem isolation 16

shutdown in multifamily housing 16

system design conditions (mechanical) 11 condensate removal 13

entrapped air 12

equipment capabilities 11

fluid flow in collectors 12 noise or erosion-corrosion 11

operating conditions 11

pressure drops 12 thermal expansion of fluids 12 temperature and pressure performance, long term 48

temperature and pressure resistance 47 deterioration of gaskets and sealants 49

deterioration of heat transfer fluids 48

effects of outgassing 49

leakage 48

thermal cycling stresses 48

thermal degradation 47 thermal storage

accessibility for maintenance 69,89

availability of parts for maintenance 71

chemical corrosion, effects on dwelling and site 87 corrosion by leachable substances 50

corrosion of dissimilar materials 50

108
Term Page Number

thermal storage (Cont.)

electrical connections, functioning of 37,81

effects of airborne pollutants 46

efficiency/output 5 equipment flow rates 11

equipment operating pressures 11 equipment operating temperatures 11

exhaust and venting, interference with 80

fluid expansion 12 hail impact resistance 30

heat transfer fluid, corrosion by 49 impact on environment 76 insulation of hot surfaces 42

interference with utility systems 80

leakage prevention 15 loads imposed by 84

long term pressure and temperature performance 48

maintenance instructions 70

maintenance skills required 71 materials compatibility 49,88

mechanical stresses 13

movement in adjacent structures, effects of 83 penetrations through building exterior 87 plumbing connections, functioning of 37,80

protection of potable water 40

removal of condensate 13

shading of adjacent structures 76 soil corrosion 45

solar degradation 45

space for 75 structural loads 21,23,25

thermal degradation 47,51

use of essential space, interference with 76

109
Term Page Number

thermostats, provision of . 7 toxic fluids 39 catch basins, provision of 39 toxic and flammable fluids, detection of 39 utilities

electrical connections, functioning of 81

operation, interference with 80

plumbing connections, functioning of 80

utility chases 75 visual characteristics of dwelling and site 91

dwelling, integration of solar subsystems with , 91

neighborhood, integration of solar dwellings with 91 wear, abrasive 47 wear of moving parts 51

wind fluttering 47

wind loads 21

110