Preliminary Guidelines for Condition

Assessment of Buildings Being

Considered for Solar Retrofit

Frank H. Lerchen

James H. Pielert

Phillip T. Chen

Building Economics and Regulatory Technology Division

Center for Building Technology

National Engineering Laboratory

U.S. Department of Commerce

National Bureau of Standards

Washington, DC 20234

QC

100

U56

31-2239

1931

Prepared for: U.S. Department of Energy

^*fice of Solar Applications for Buildings

fice of the Assistant Secretary

Conservation and Renewable Energy

ishington, DC 20585

y 1981

NATIONAL BUIUAU

OF STANDARDS

LIBRARY

NBSIR 81-2289

<<* PRELIMINARY GUIDELINES FOR CONDITION

ASSESSMENT OF BUILDINGS BEING

CONSIDERED FOR SOLAR RETROFIT

SEP 1 6 1981

not o_cc Quod

. u £

HO,

iq % I

Frank H. Lerchen

James H. Pielert

Phillip T. Chen

Building Economics and Regulatory

Technology Division

Center for Building Technology

National Enginekering Laboratory

U.S. Department of Commerce

National Bureau of Standards

Washington, DC 20234

July 1981

Prepared for: U.S. Department of Energy

Office of Solar Applications for Buildings

Office of the Assistant Secretary

Conservation and Renewable Energy

Washington, DC 20585

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler. Director

ABSTRACT

This preliminary report was developed with the intent of assisting government

officials, designers, builders, code officials, and others involved with

evaluating the condition of the systems (structural, heating, etc.) of

existing buildings in order that the impact of solar modifications on them

may be assessed.

The report describes evaluation methods specifically for use with the

structural materials of concrete, wood, masonry, and steel, as well as for

heating/ventilating/air conditioning (HVAC), plumbing, and electrical systems. Engineering information is presented in two stages: (1) preliminary

evaluation methods easily used by the building facilities engineer, and (2)

secondary evaluation methods which are more detailed and sophisticated, and

which may include information obtained away from the building site.

Comparative tables are provided to aid in making a selection of the

evaluation method most appropriate for the particular parameter to be tested.

Other tables describe the common problems associated with each material or system and their possible causes as well as the impact they may have on the

proposed solar retrofit.

Key words: building rehabilitation; concrete; electrical; evaluation; HVAC;

masonry; plumbing; solar; solar retrofit; steel; structural

systems; test methods; wood.

iii
ACKNOWLEDGMENTS

The authors would like to extend appreciation to those individuals who

generously provided information on many aspects of the evaluation of existing buildings being considered for solar retrofit. Special appreciation is

extended to Mr. James G. Gross , Chief, Building Economics and Regulatory

Technology Division, Center for Building Technology (CBT), National Bureau

of Standards (NBS), for overall direction of the report; Mr. William J. Meese,

General Engineer, NBS, for input in the electrical area; Dr. James R. Clifton,

Research Chemist, NBS, for input on evaluation of concrete; and Ulesia B. Gray,

Editorial Assistant, Word Processing Center, and Mary M. Chaney, Secretary,

Rehabilitation Technology Group, CBT, NBS, for outstanding clerical support.

It is with great appreciation, also, that the authors acknowledge the efforts

of individuals outside the National Bureau of Standards for their review of

the report concerning technical aspects. In particular, appreciation is

extended to Dr. V. M. Malhotra, P.E. , Head, Construction Materials Section,

Department of Energy, Mines and Resources, Canada, for his review and comments

on concrete evaluation; Mr. William L. Galligan, Project Leader, Engineering

Properties of Wood, Forest Products Laboratory, Forest Service, U.S. Department of Agriculture; Mr. Alan H. Yorkdale, P.E. , Director of Engineering and

Research, Brick Institute of America; Mr. Peter Jacobs, Systems Analyst, Solar

Environmental Engineering Company; and Mr. Scott Heider, P.E, consultant.

iv
PREFACE

The study to develop this report was conducted by the Rehabilitation

Technology Group, Building Economics and Regulatory Technology Division,

National Bureau of Standards. The report contains a general description of

methods currently available for condition assessment of the structural;

heating, ventilating, and air conditioning (HVAC); electrical; and plumbing

systems of an existing building, in order to determine the feasibility of

rehabilitation for solar retrofit.

The intended audience for this report includes government officials,

designers, builders, code officials, and others involved with making technical

decisions on building rehabilitation as related to solar retrofit. It is

not intended for use by nontechnical persons who are unfamiliar with the

performance of building materials and basic engineering principles.

The report was developed with funding from the Department of Energy (DoE) as part of the Solar Federal Buildings Program (SFBP) which was developed to

stimulate the growth and improve the efficiency of the solar industry as applied to Federal buildings.

This report is not presented as an all-inclusive listing of building condition

assessment methods. Additionally , neither NBS nor DoE endorses or claims

to have evaluated all of the methods described in this report. It is anticipated that this preliminary report will be updated, and the authors would

appreciate comments and recommendations for revisions

.

v
TABLE OF CONTENTS

Page

LIST OF TABLES . viii

LIST OF FIGURES ix

SI CONVERSION UNITS x

1. Introduction 1 1.1 Purpose of the Report 1 1.2 Authorization 1 1.3 Need for Analysis 1 1.4 Background 2

2. Preliminary Evaluation Methods 5 2.1 On-Site Investigation 5 2.2 Off-Site Investigation 7 2.3 Destructive vs. Nondestructive Evaluation 7

3. Guidelines for Structural Systems 10

3.1 General Considerations 10

3.2 General Inspection Guidelines - Structural Components .... 13

3.3 Concrete Systems 17

3.4 Wood Systems 23

3.5 Masonry Systems 32

3.6 Metal Systems 43

4. Guidelines for Heating, Ventilating, and Air Conditioning (HVAC

)

Systems 49

4.1 General Considerations 49

4.2 Preliminary On-Site Investigation Guidelines - HVAC

Systems 49

4.3 HVAC Problems and Potential Impact on Solar Retrofit 57

5. Guidelines for Plumbing Systems 61

5.1 General Considerations 61

5.2 On-Site Evaluation Guidelines - Plumbing Systems 61

5.3 Plumbing Problems and Potential Impact on Solar Retrofit . 63

6. Guidelines for Electrical Systems 66

6.1 On-Site Evaluation Guidelines - Electrical Systems 66

6.2 Electrical Problems and Potential Impact on Solar

Retrofit 69

REFERENCES AND SUGGESTED ADDITIONAL READINGS 71

vi
TABLE OF CONTENTS - (Continued)

Page

APPENDIX A - TYPICAL FORMS FOR COLLECTION OF DATA DURING

PRELIMINARY ON-SITE INVESTIGATION . A-l

APPENDIX B - RECOMMENDED EQUIPMENT FOR FIELD INSPECTION B-l

APPENDIX C - POTENTIAL SOURCES OF INFORMATION ON BUILDINGS BEING

CONSIDERED FOR SOLAR RETROFIT . C-l

APPENDIX D - METHODS FOR DETAILED EVALUATION OF SYSTEMS D-l

APPENDIX D.l - Concrete Systems . D-l

APPENDIX D.2 - Wood Systems D-5

APPENDIX D.3 - Masonry Systems D-8

APPENDIX D.4 - Metal Systems D-13

APPENDIX D. 5 - HVAC Systems D-16

APPENDIX D.6 - Plumbing Systems D-32

APPENDIX D.7 - Electrical Systems D-35

vii
LIST OF TABLES

Page

Table 1. Loads from Roof Coverings 11

Table 2. Size and Weight of Typical Chillers 12

Table 3. Weight of Typical Storage Tanks 12

Table 4. Weight of Typical Storage Tanks 20

Table 5. Preliminary Assessment Checklist (Concrete) 21

Table 6. Test Methods for Wood 27

Table 7. Preliminary Assessment Checklist (Wood) 28

Table 8. Test Methods for Masonry 36

Table 9. Preliminary Assessment Checklist (Masonry) 37

Table 10. Preliminary Assessment Checklist (Metals) 46

Table 11. Preliminary Assessment Checklist (HVAC) 58

Table 12. Preliminary Assessment Checklist (Plumbing) 64

Table 13. Preliminary Assessment Checklist (Electrical) 70

Table 14. Concrete Evaluation Techniques ........................... D-2

Table 15. Wood Evaluation Techniques D-6

Table 16. Masonry Evaluation Techniques ............................ D-9

Table 17. Metal Evaluation Techniques D-14

Table 18. Residential Duct Air Velocity D-24

Table 19. Capacity Correction Factors for Entering Conditions

Other Than 60 °F EAT and 180°F EWT D-27

Table 20. Correction Factors for Off Design Performance of Various

Natural Convective and Radiant Heat Transfer Equipment ... D-28

viii
LIST OF FIGURES

Page

Figure 1. Engineering Evaluation Plan . .... 5

Figure 2. Concrete Test Methods and Parameters 19

Figure 3. Historic Energy Consumption Record 50

Figure 4. Existing HVAC Design Identification 52

Figure 5. Pitot Tube Measurement Locations for Rectangular and

Large Round Ducts 56

Figure 6. Blower Static Pressure Tap Locations 60

Figure 7. Simulated Blower Characteristic Curve D-21

Figure 8. Effects of Water Flow Rate on Coil Heat Transfer for

20°F Water Temperature Drop at 200° Water Supply

Temperature D-25

Figure 9. Increase in Air Flow Required to Maintain Constant

Heating Coil Output with Decrease in Supply Water

Temperature D-25

Figure 10. Double Row Baseboard Unit D-27

Figure 11. Operating Modes of Air Type Solar System with Rock

Bed Storage D-30

Figure 12. Water-Based System with Tank Storage D-30

Figure 13. Parallel Solar-Heat Pump System D-31

Figure 14. Series Solar-Heat Pump System D-31

Figure 15. Solar Absorption Cooling System ". D-31

ix
MOST COMMON SI UNITS AND THEIR

EQUIVALENT VALUES IN

CUSTOMARY UNITS

INTERNATIONAL CUSTOMARY 1 (SI) UNIT UNIT APPROXIMATE CONVERSION

LENGTH peter (») foot (ft) -1 m “ 3.2804 ft millimeter (mb) inch (in) 1 EM - 0.0394 in

AREA square meter (m2

) square yard (yd ) 1 m

2 - 1.1960 y<5 2 square millimeter (mm ) square foot (ft2

) square inch (in2

)

1 m

2 1 ran2 - 10.764

- 1.55 x

ft2

. , 10' 3 in

VOLUME cubic meter (m3

) cubic yard (yd 3

) 1m3 - 1.3080 yd 3

cubic millimeter (ran3

) cubic foot (ft 3

) cubic inch (in3

)

1 m

3 1 <m?

“ 35.315

- 61.024 ft* _ 6 x 10 it

CAPACITY liter (L) gallon (gal) 1 L - 0.2642 gal

VELOCITY, SPEED meter per second (m/s) foot per second (ft/s) 1 m/s - 3.2808 ft/s

kilometer per hour (km/h) mile per hour (mile/fa or m.p.h) 1 km/h » 0.6214 mile/h

ACC ELLERAT ION meter per second squared (m/s ) foot per second squared (ft/s2

) 1 m/s2 - 3.2808 ft/s2

MASS metric ton (t) ton (2000 lb) 1 t - 1.1023 ton kilogram (kg) pound (lb) 1 kg » 2.2046 lb gram (g) ounce (or) 1 8

- 0.0353 O2

DENSITY metric ton per cubic meter (t/m3

) ton per cubic yard (ton/yd 3

) 1 t/m3 = 0.8428 ton/yd 3 kilogram per cubic meter (kg/m3

) pound per cubic foot (lb/ft 3

) 1 kg/m3 - 0.0624 lb/ft 3

FORCE kllonewton (kN) ton-force (tonf) 1 kN * 0.1124 tonf

newton (N) kip (1000 Ibf

)

pound-force (lbf)

1 kN

1 N

- 0.2248

- 0.7376 kip

lbf

MOMENT OF FORCE, kllonewton meter (kN.m) ton-force foot (tonf. ft) 1 kN-m - 0.3688 tonf /ft

TORQUE newton meter (N*m) pound-force inch (lbf -in) 1 N.m « 8.8508 lbf -in

PRESSURE, STRESS megapascal (MPa) ton-force per square inch (tonf/in ) 1 MPa • 0.0725 tonf/in2 kilopascal (kPa) ton-force per square foot (tonf /ft 2

) 1 kPa - 10.443 tonf /ft

pascal (Pa)

pound-force per square inch(lbf /in2

) pound-force per square foot (lbf /ft2

)

1 kPa

1 Pa

- 145.04

m 20.885 lbf /in 2 lbf /ft 2

WORK, ENERGY, kilojoule (kJ) British thermal unit (Btu) 1 kJ -= 0.9478 Btu QUANTITY OF HEAT loule (J) foot pound-force (ft*lbf) 1 J - 0.7376 ft- lbf

COEFFICIENT OF HEAT watt per square meter kelvin Btu per square foot hour degree 1 W/(m2 -K) - TRANSFER (U-Value) (W/m^.K) Fahrenheit (Btu/f

t

2 .h° c F) 0. L761 Btu/ (f t .h* F)

THERMAL CONDUCTIVITY (k-Value) watt per meter kelvin (W/m«K) Btu per foot hour degree Fahrenheit

(Btu/ft-h. °F)

1 W/(m-K) « 0.5778 Btu/(ft-h-°F)

NOTES: (1) The above conversion factors are shown to four significant digits, where appropriate.

(2) Unprefixed SI units are underlined. (The kilogram, although prefixed, is an SI base unit.)

REFERENCES:- NBS Metric Guidelines, LC1C56, August 1977; NBS Special Publication 330, "The International System of Units (SI);” NBS Technical Note 938, "Recommended Practice for the Use of Metric (SI) Unite In Building Design and Construction;" ASTM Standard E621-78, "Standard Practice for the Use of Metric (SI) Units in Building Design and Construction;" ANSI Z210-1976, "American National Standard for Metric Practice;" ASTM E380-76, or IEEE Std. 268-1976.

X
i. introduction

1.1

PURPOSE OF THE REPORT

This preliminary report was prepared to show Federal agencies what evaluation

methods are available to determine whether buildings in their inventory are suitable for solar energy retrofit. It describes methods for developing the

engineering information needed to determine whether the building and its

mechanical/electrical systems can be retrofitted for solar energy under the

Solar Federal Buildings Program (SFBP).

The report is intended to be used by the agency's facilities engineer to

conduct on-site and/or off-site investigations of the building structure and

its systems. Engineering information is developed in two stages: (1) preliminary information derived from reasonably unsophisticated procedures, and

(2) secondary information derived from more detailed or sophisticated procedures. The ultimate decision to recommend solar retrofit should be made by

the facilities engineer and associated consultants.

1 .

2

AUTHORIZATION

Funding for the report was provided by the Department of Energy (DoE) as part of the Solar Federal Buildings Program (SFBP). This multi-year program

is designed to stimulate the growth and improve the efficiency of the solar

industry by providing funds to Federal agencies for the design, acquisition,

construction, and installation of commercially applicable solar domestic

hot water, heating, cooling, and process systems in new and existing Federal

buildings. The SFBP was authorized under Title V, Part 2 of the National

Energy Conservation Policy Act, enacted on November 2, 1978 (PL 95-619).

Program implementation began with the approval of the procedures published

in the October 19, 1979, Federal Register (Vol. 44, No. 204), and it became

fully operational with the publication of the Federal Energy Management and

Planning Programs (FEMP) Final Rule in the January 23, 1980, Federal Register.

If a Federal agency plans to retrofit a building for solar energy under the

SFBP, it must submit to the DoE a proposal for each project. Each proposal

must contain: (1) general project information; (2) site and building description; (3) building load information; (4) solar system description; and

(5) auxiliary (or backup) system information, including the method for selecting the solar design proposed. The guidelines presented in this report will

be useful in preparing the required information. The October 19, 1979,

Federal Register contains more specific information on the subject.

1.3

NEED FOR ANALYSIS

The rapid rise of oil prices and the apparent limit of known sources has

resulted in a greater concern for efficient Federal utilization of available

energy sources. Since solar energy is a viable supplement to conventional

energy sources, Federal agencies are expected to consider its use. However,

the cost benefits of solar energy must be considered against other available

energy sources. For example, solar energy is generally considered to be

1

- Electrical: Additional electrically operated equipment such as blowers,

pumps, water chillers or heat pumps will require the modif icatioon of the

existing power supply system, including possible additional power capacity,

wiring and controls.

Figure 1 provides an overview of the sequence recommended for determining

whether a particular building and its systems can support a solar retrofit.

If solar retrofit is determined to be feasible, further economic evaluation

may be required to be provided by others. The information provided by the

engineering evaluation will be useful to the retrofit designer when a decision has been made to proceed, although the designer ultimately will have

to determine exactly what evaluation information is required for a complete

design.

3
J

J

4

Preliminary

EwaSyatloo

Agency

Decision

Detailed

Evaluation

(teeritaf

m

main

text)

(described

in

appendix)
2. PRELIMINARY EVALUATION METHODS

2.1 ON-SITE INVESTIGATION

Visual inspection of a building and simple assessment procedures will provide

most of the information required to determine the condition and capability of

the building and its systems. Most defects (such as missing components,

cracks, corrosion, misalignment, etc.) affecting solar retrofit can be

detected visually.

The on-site inspection procedure generally includes:

1) General site inspection.

2) Gathering of existing documents (plans, specifications, etc.).

3) Survey of building condition, including sketches and photographs.

4) Gathering of specimens for evaluation.

5) Simple field tests.

6) Interviews with owners /occupants.

The information obtained during inspection should include:

1) A list of materials, components, and systems existing in the building

(including structural; heating, ventilating, and air conditioning (HVAC);

plumbing; and electrical items).

2) Condition and capacity of existing components (e.g., extent of deterioration

of concrete structural members; nameplate data for fans and pumps; etc.);

3) Actual occupancy related loads (structural, heating, plumbing, etc.) to

which the building is subjected.

To organize the accumulated data during the on-site investigation, a project

dossier should be established consisting of a project notebook and a file

containing all notes, correspondence, and documents (as well as collected

reference material) concerning the prospective solar retrofit project.

2.1.1 Project Notebook and Forms

The project notebook should contain the following information (typical forms

are shown in appendix A).

1 ) General Building Information (See sample form A-l)

Form A-l is designed to provide broad administrative and technical information

relative to the structure under investigation. More detailed data is collected

on additional forms described below.

2) Component /Assembly Information (See sample form A-2)

Form A-2 is designed to provide detailed information relative to the physical

condition of specific components and assemblies of the various building systems

5
(structural, plumbing, HVAC, and electrical). Data should be cross-referenced

to other forms.

3) Journal Entry List (See sample form A-3)

Form A-3 is used to provide a record of all important agreements, decisions

or actions made by the facilities engineer, or his staff. If the remarks con- cerning the entry are extensive, then an attachment should be made, noted

under the remarks and filed in the dossier with the Journal Entry number

clearly marked.

4) Contact List (See sample form A-4)

Form A-4 is designed for the orderly collection of information from people

contacted in the course of the preliminary investigation. For example, this

form can be used to identify all past or present occupants of the building,

the owner or manager of the building, the architect, engineers, etc.

5) Document List (See sample form A-5)

Form A-5 is used to complete information on plans, specifications, etc.,

which might aid in the investigation of the building.

6 ) Photograph List (See sample form A-6)

Form A-6 provides a record of all photographs of the building and adjacent

areas taken or collected by project staff.

7 ) Sketch List (See sample form A-7)

Form A-7 provides for orderly collection of sketches relative to the building

or component condition. It should be cross-referenced to the photograph list.

8 ) Specimen List (See sample form A~8)

Form A-8 provides a record of samples removed from the building in the course

of the preliminary investigation. The sketches of the sample locations along

with photographs and sketches of the samples themselves should be entered on forms A-6 and A-7.

2.1.2 Project Files

The project files should include the following items;

1) General Correspondence

2) Journal Entry Supplements

3) Collected Documents and Citations

4) Photographs and Negatives

5) Field Reports and Sketches

6) Test Results

6
7) Analytical Studies

8) Evaluation Report

2.1.3 Field Inspection Equipment

Appendix B contains a list of items which would be useful in conducting an on-site investigation.

2.2 OFF-SITE INVESTIGATIONS

Additional information also is needed which is obtained away from the building

site. This information compliments the on-site investigation and provides a complete picture of a building and its potential for solar retrofit. It con- sists of: (1) analyses of the building systems, (2) simple laboratory tests

of specimens removed from the building, and (3) additional building documents.

The latter includes drawings and specifications, construction records, operation and maintenance records, records of alterations made to the buildings

and systems, information on material properties, and records describing

site conditions. Sources of this information are the Federal agency headquarters, the building facilities engineer, the building contractor, the

surveying contractor, and the building designer. Appendix C contains a more

complete list of such information and potential sources.

Existing documents should not be used by themselves to evaluate a building

since frequently they may not reflect actual conditions. Therefore, an on-site

investigation of the as-built conditions always is recommended in conjunction

with a review of existing documents.

Data obtained off-site may be handled and filed in the same manner as is

described above for on-site data.

2.3 DESTRUCTIVE VS. NONDESTRUCTIVE EVALUATION

Throughout the structural portions of this report, evaluation methods will be

referred to as nondestructive or destructive. A definition of each is provided

below along with advantages and limitations.

A. Nondestructive Evaluation is the process of inspecting, evaluating, and/or

measuring the performance or properties of materials or systems in a manner which will not change, damage, or destroy the properties or affect

the service life of the specimens [3].

1) Advantages

° Can be performed in-situ with little or no damage to the specimen.

° Different tests can be used on the same test member simultaneously

or sequentially.

° The same test can be repeated on the same test member.

7
° The cumulative effect of the time in service of the test member

can be measured directly.

° Little or no preparation is required to be performed on the test

member.

° The equipment often is portable for in-situ use.

° Labor costs usually are low, especially for repetitive testing

of similar test members.

2) Limitations

° Sometimes interpretation of the test results must be accomplished

by skilled, experienced technicians.

° In the absence of proven correlation, the meaning and significance

of the test results could be interpreted differently by various

evaluators.

° Some nondestructive tests require very sophisticated and expensive

testing equipment.

° Often only qualitative or comparative measurements of the properties

of the test sample can be made.

B. Destructive Evaluation is the process of inspecting, evaluating, and/or

measuring the properties of materials or systems in a manner which can change, damage, or destroy the properties or affect the service life of

the test specimen [3].

1) Advantages

0 Measurements are direct and usually reliable.

° Measurements are quantitative and usually are valuable for

determining the existing properties of the test member.

° Skilled technicians usually are not required to interpret test

results.

0 There usually is a direct correlation between test results and the

in-situ properties of the test sample - thus leaving little to

interpretation among various evaluators.

2) Limitations

° Applicable only to a test sample. Further proof may be required

that the test sample is representative of the rest of the building

members.

8
° Tested members are damaged or their service life is affected.

° Often it is not possible to repeat tests on the same member of

the building because of the destructiveness of the test.

° The cumulative effect of the time in service of the test member

cannot be measured directly, but can only be inferred from tests

made on the members at different lengths of time.

° Difficult to use in-situ.

° Pre-test preparation work usually is required.

° Often the equipment and manpower costs are high.

« 9
3. GUIDELINES FOR STRUCTURAL SYSTEMS

3.1 GENERAL CONSIDERATIONS

3.1.1 Structural Condition Assessment

The assessment of existing structural components should include strength,

stiffness, and stability considerations. On-site inspection of a building can provide a great deal of information relative to these properties.

3.1.2 Structural Loadings

The addition of solar components to an existing building often will change

structural loadings. These changes could be in the form of additional dead

loads from collectors, absorption chillers, water storage tanks, or rock

beds; dynamic or vibrational loads from rotating or reciprocating equipment;

or changes in live load caused by the rehabilitation of the building (e.g.,

change in occupancy). Tables 1, 2 and 3 provide guidance on the types of

such loading to expect. Not only should new loading be considered but

modifications to the structural system should be analyzed. Examples include

the cutting of chases in existing floors, walls, or roof systems for the passage of mechanical/electrical support systems, and the modification to an existing building for passive solar benefits where large openings may be

added to the building envelope. Good engineering practice and careful

assessment should be used to evaluate the impact of revised loadings.

3.1.3 Environmental Changes

The addition of solar components can create serious problems for stuctural

systems by changing the ambient moisture and temperature conditions. Minor

structural accommodations (e.g., cracks in plaster) may occur during the time

it takes for the building to adapt to the proposed new conditions. The preliminary evaluation should attempt to anticipate these problems and to assess

the degree of severity or significance of such problems on the building.

3.1.4 Date of Building Construction

Data relative to the properties of materials in an existing building can be

estimated if the date of construction is known. Approximate strength values

generally are sufficient for analytical purposes in assessing structural

characteristics. The date of a building can provide clues relative to

design codes, engineering standards, construction techniques and materials

used, and hence the structural performance to be expected. For example, the

design yield strength of structural steel has changed considerably over the

10
TABLE 1

LOADS FROM ROOF COVERINGS 1 /

Asbestos Shingles

Pa x 10 1 120

i lbf/ft

1 4 Asphalt Shingles 95 2 Copper or Tin 48 j 1 Corrugated Iron 96 2 Clay Tile (for mortar add 10 lb.):

2" Book Tile 574 1 12

3" Book Tile 958 | 20

Roman 574 1 12

Spanish 919 1 19

Ludowici or Shingle 479 1 10

Cement Tile 766 16

Composition

:

Three-ply ready roofing 48 1 Four-ply felt and gravel 263 5.5

Five-ply felt and gravel 287 1 6

Wood-Sheathing, per inch thickness 144 1 3

Slate, 3/16 inch 335 | 7 Slate, 1/4 inch 479 1 10

Skylight, metal frame 3/8" wire glass 383 1 8

Wood shingles 144 1 3

Insulation, per inch thickness 48 1 Gypsum Plant, 2 inch 574 12

Metal Deck (1 1/2" with ribs 6" o.c.) 120 1 2.5

1/ Roof loads for typical flat plate collectors and supports are in the

range of 0.5-0. 7 Pa (10-15 lbf/ft^).

11
TABLE 2 [7]

SIZE AND WEIGHT OF TYPICAL CHILLERS

Derated

Capacity

Maximum

Rated

Capacity

Dimensions

L x W x H

Wt (lb)

(wet

)

Average Floor

Load (psf)

(kPa) (lbf/ft 2

)

30t lOOt 11' x 5' x 7' 11,260 9.8 205

60t 200t 14' x 5' x 8' 16,350 11.2 234

105t 350t 19' x 6 x 8' 24,700 10.4 217

180t 600t 22' x 7 ' x 9' 35,250 11.0 229

285t 950t 22’ x 8’ x 11' 57,400 15.6 326

375t 1 , 250t 25' x 10’ x 12’ 85,700 16.4 343

TABLE 3 [7]

WEIGHT OF TYPICAL STORAGE TANKS 1 /

Capacity Weight Including Water

unpressurized pressurized

litres gal kg lb kg lb

1,893 500 2,073 4, 570 2,499 5,510

3,785 1,000 4, 182 9, 219 4, 951 10, 915

9,465 12,500 6, 187 13,640 7,317 15, 132

1 / Storage tanks are sized commonly at 3. 8-7. 6 litres (1-2 gallons)

storage per 0.1 m

2 (ft 2

) of collector area.

of

12
years. In lieu of costly testing of steel in an existing building it may be

appropriate to assume conservative values based on the following relationship:

Date Yield Point [4,5,6]

(MPa) (lbf/in2

)

Constructed prior to 1905

Constructed 1905-1932

Constructed 1933-1963

Constructed after 1963

f = 172.37

fy = 206.84

f

y

= 227.53

f

y = 248.21

25.000 psi

30.000 psi

33.000 psi

36.000 psi

3.2 GENERAL INSPECTION GUIDELINES — STRUCTURAL COMPONENTS

As shown in figure 1 and discussed in section 2.1, the on-site investigation

consists of a general site examination and a building condition survey. While

the major emphasis should be on the assessment of structural components which

may be affected by the solar retrofit, it is necessary to make an overall

review of the condition of the whole building. This is especially significant where additional structural loadings or modifications are anticipated.

The following general inspection guidelines will be useful in this assessment.

3.2.1 Foundations

The foundation is one of the most important structural components to assess.

It should be anticipated that such things as added loads or changes in soil

drainage patterns around the building can impact the building foundation

detrimentally. References [8, 9, 10] provide the following guidelines:

(a) Check for soft and crumbling mortar in foundation walls. This could

be serious if it is associated with any signs of sag in the structure.

(b) Foundation wall cracks usually are diagonal, starting from the top,

the bottom, or the end of the wall. If the cracks do not extend to

at least one edge of the wall, they probably are not caused by

foundation problems, but are more likely due to other structural

problems (see table 5 and table 9).

(c) Be sure the ground slopes away from the foundation wall so that

rain water drains off properly.

(d) Downspouts should have splash blocks to divert water away from the

building.

(e) Although it usually is difficult to determine the condition of a footing without excavating the foundation, structurally unsound

footings usually will be indicated either by large cracks or by

settlement in the foundation walls.

(f) Leaning, buckling, or bulging foundation or bearing walls may be

the result of a number of hidden or interacting problems. For

13
example, they may be the result of differential building settlement

or failure of a structural beam or girder. (g)

If new heavy loads are to be added to the existing foundation, it

will be necessary to check it for ability to carry the new loads.

If details of the foundation design and the soil bearing value cannot

be determined from existing drawings and reports of subsurface soil

investigations, it may be necessary to: (1) excavate adjacent to an outside wall to determine the type of existing foundation and

(2) conduct a subsurface soil investigation (soil borings). Results

from the subsurface soil investigation can be used to support the need

for new foundations under heavy loads or to prove the adequacy of

existing foundations.

3.2.2 Exterior Walls

(a) Check for plumbness. Use a plumb line. Out of plumb exterior

walls can be a sign of serious foundation problems.

(b) Sight along wall for any sign of bulges which could indicate major

structural problems.

(c) Doors that do not line up squarely in their frames can be another

sign of possible foundation problems.

(d) Check that all joints between dissimilar materials (e.g. , wood and

masonry joints) around door frames, window frames, and decorative

trim are tightly caulked or properly flashed to prevent water

penetration.

(e) Check for vertical or zig-zag cracks through bricks and mortar

that can be an indication of uneven settling.

(f) Check that mortar joints are sound (not soft and crumbling) and

that no bricks are missing or loose.

(g) Look for any sign of spalling, cracking, or crumbling of exterior

stonework.

(h) Check for any loose, cracked, or missing clapboards that could

admit water into the building.

(i) Identify any loose, thin, or badly weathered siding or shingles which

are an open invitation to water and rot.

(j) Check for rotting of the siding or erosion of the exposed portion of

the cellar or basement walls which often results from missing or leaking gutters.

14
3.2.3 Roof

(a) Inspect for sagging condition of the roof. Especially attempt to

examine the rafters, purlins, collar beams, and ridge boards wherever

possible. Where applicable check the condition of the roof boards

from inside the attic.

(b) Look for evidences of a leaking roof. This condition will be

indicated by loose plaster or peeling or stained paint and wall

paper.

(c) Check condition of gutters and rain leaders around the entire building

to insure proper drainage of water. Evidences of the lack of gutters

(or leaking gutters) are: (1) rotting of the siding, or (2) erosion

of the exposed portion of the cellar or basement walls.

(d) All existing dead and live loads on the roof should be summed to

determine the accumulative existing loads and to determine whether

the additional load of 0.5 to 0.7 kPa (10 to 15 lbf/ft^) imposed by

typical solar components can be supported by the structure. The design

capacity should be checked with respect to expected snow, ice, and

wind loads for the local geographical area, as well as the dead loads

of the roofing materials.

(e) If the existing roof is composed of a steel deck on steel joists, and

new heavy concentrated dead loads are to be imposed on the deck by

solar equipment, be sure the joists have been designed for twice the

static operating weight of the equipment. Be sure there is enough

room to reinforce the top chords of the joists for any new concentrated

loads which may be applied between panel points. Since any new con- centrated loads which must be applied to the bottom chords will have

to occur at panel points, it will be necessary to check that access

to these points is possible. Existing joists should be checked to be sure they can support newly imposed loads without exceeding a maximum

deflection of 1/360 x span.

(f) Be sure that existing conditions will accommodate roof mounted

equipment supports which will permit easy access for roof maintenance.

3.2.4 Attic

(a) Look for signs of leaks (e.g., dark water stains) on the underside of

the roof, especially around chimneys, valleys, and eaves.

(b) Check for proper ventilation, especially for signs of mildew on underside of roof boards.

15
3.2.5 Interior Spaces

(a) Look for signs of damp plaster which may indicate the existence of

leaks from the roof or internal pipes.

(b) Check for any loose or spongy plaster in walls or ceilings which

could indicate the existence of leaks.

(c) Substantial vibration (bounce) of stairways; or gaps between treads,

risers, and side stringers of stairs may indicate structural problems.

(d) Check to see if the flooring is in good condition (flooring covered

with linoleum, carpet, etc. , can harbor unseen problems).

(e) See if floors have a pronounced sag or tilt. A simple test can be

performed with a marble (to see if it rolls) or with a level. A

sag or tilt could indicate normal settling, or structural problems.

(f) Jump on floors to see whether the floors vibrate or the windows rattle

(this would indicate inadequate support caused by undersized beams,

inadequate bridging, cracked joists, or rotted support post, etc.).

(g) Look for signs of water leakage around window frames.

(h) If outside light can be seen through openings around window rails

and door jams, the condition of the support girders, posts, and

studs should be questioned. This condition often is evidence that some of these members may be termite infested or rotted and may be

causing the outside wall to sag.

(i) Wherever possible, new columns or equipment supports should be placed

directly over existing columns. Therefore, the interior of the building should be inspected to determine whether there are any conditions

which would prevent this from being accomplished.

3.2.6 Basement

(a) Probe the sills (wood beams at the top of the foundation walls) with

a penknife, awl, or ice pick for signs of rot or termites.

(b) If the mortar between bricks or concrete blocks in foundation walls

is heavily eroded (or if other evidences of erosion of the exposed

portion of the basement wall exist) check for missing or leaking

gutters.

(c) Check for any signs of dampness on the underside of floors around

pipes. If left uncorrected, this can cause wood rot.

(d) Signs to look for which warn of probable periodic flooding are:

rust spots, efflorescence or mildew on walls, and material stored

on top of bricks or boxes to raise it above floor level.

16
(e) Look for sagging floors, rotted support posts, or jury-rigged props

to shore up weak flooring.

(f) Check for general condition of the plumbing (e.g. , patches on waste

pipes indicate advanced age or structural movement).

3.3 CONCRETE SYSTEMS

Since concrete came into general use as a building material in the latter part

of the nineteenth century, many existing buildings currently being considered

for solar retrofit require application of concrete condition assessment techniques. Figure 2 summarizes the available techniques for condition assessment

including visual techniques and the more complicated test procedures. The

remainder of this section is concerned with visual inspection guidelines

while the more detailed procedures are discussed in appendix D.l.

3.3.1 Preliminary Evaluation of Concrete Systems

Generally, visual/optical inspection is the most satisfactory, least expensive,

and most commonly used method for determining the shape and dimensions of

concrete components and for preliminary detection of surface flaws (such as cracks, roughness, scratches, discoloration, etc.). It can be performed with

or without the use of optical aids (such as low-power magnifiers). Defects

such as missing components, cracks, erosion, corrosion, and misaligned joints,

often can be detected with the naked eye. With the use of five to ten power

magnifiers, even surface flaws as small as a few microns wide can be detected.

Table 4 summarizes visual inspection techniques for concrete.

The most obvious advantage of using the visual method to evaluate surface

flaws in concrete is that it is inexpensive and requires no special equipment.

However, the visual inspection method can be time consuming and is completely

dependent upon the visual acuity, experience, and training of the inspector.

It should be understood that no subsurface information can be obtained using

this technique and that, even for surface conditions, a correlation already

must have been established between the surface conditions and serviceability

of the concrete.

During the visual/optical inspection, the following significant structural

aspects should be checked or considered:

A. Concrete foundation cracks which are diagonal, starting from the top,

the bottom, or the end of the wall. If the cracks do not extend to at

least one edge of the wall, they probably are not caused by foundation

problems, but are more likely due to other structural problems. It is

important to determine the cause of these problems and to remedy the

problem because the addition of retrofit solar equipment loads on the

building could aggravate the problem further.

B. When new heavy loads are expected to be added to the existing concrete

foundation, it will be necessary to check it for structural adequacy. If

17
details of the concrete foundation design and the soil bearing value can- not be determined from existing drawings and reports of subsurface soil

investigations, it may be necessary to: 1) excavate adjacent to an outside wall to determine the type of existing foundation and 2) conduct a subsurface soil investigation (soil borings). Results from the subsurface

soil investigation can be used to support the need for new foundations

under heavy loads or to prove the adequacy of existing foundations.

C. All existing dead and live loads on the concrete roof structure should be

summed to determine the accumulative existing loads and to determine

whether the additional loads imposed by the retrofit solar components can be supported by the existing concrete structure. The design capacity

of the affected components of the concrete structure should be checked

with respect to expected snow, ice, and wind loads for the local

geographical area, as well as the dead loads of the roofing materials.

D. Wherever possible, new columns or equipment supports should be placed

directly over existing columns. Therefore, the interior of the building

should be inspected to determine whether there are any conditions which

could prevent this from being accomplished.

3.3.2 Concrete Problems and Potential Impact on Solar Retrofit

A checklist (table 5) can be used to assist in determining what problems

exist in a concrete structure and to make a preliminary determination of the

impact that the problem may have on the solar retrofit. If it is determined

that a more complete understanding of the nature or cause of the problem is

necessary, further reference is given in the table to a more detailed

description in appendix D.l.

18
CONCRETE TEST METHODS AND PARAMETERS

NONDESTRUCTIVE

TESTS

,V>

a

DESTRUCTIVE

TESTS

PARAMETERS <5^

^^^vo*~ *,c°~ ^^^ ^ ye'- Dimensional Characteristics Thickness of Slabs • • • • • •

Size and location of rein- forcing and other electrically conductive components • • • • • •

Quality and Strength Characteristics

Quality of Concrete © • • • • • • • •

Quality of Aggregate • • •

Uniformity • • • • • 9 • •

Variable Compaction • © • •

Compressive Strength © • • © • •

Moisture Content • • •

Cement Content • • •

Density and Internal Structure of Concrete • • • • •

Modulus of Elasticity • • • •

Condition of Reinforcing • • • •

Flaws Surface Flaws • • • • • •

Internal Flaws (Voids, cracks, etc.) • • • • • • • •

Voids in grouting of post- tensioned prestressed concrete •

Deficiencies in Joints •

Substratum Voids •

Load Distribution and Stress/Strain

Load distribution and strain as detected by surface distortion patterns •

Bonding Stress •

Failures Under Stress •

Differential Structural Movements •

FIGURE 2

19
METHODS

CAPABILITIES

DEGREE

OF

SENSITIVITY

APPLICATIONS

ADVANTAGES

LIMITATIONS

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20

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TABLE

5.

PRELIMINARY

ASSESSMENT

CHECKLIST

(CONCRETE)

21
TABLE

5.

PRELIMINARY

ASSESSMENT

CHECKLIST

(CONCRETE)

(CONTINUED)

22
3.4 WOOD SYSTEMS

3.4.1 General

The practice of evaluating wood must focus on identification of those

characteristics that define its performance (such as density, knots, moisture

content, etc.). In existing buildings being considered for solar retrofit,

questions of performance of wood components must address: (1) evidence of

degradation of these products by the environment (e.g. , moisture, temperature,

chemicals, etc.); (2) presence of properly specified product grade and size;

and (3) proper joining of components. Assessment techniques for wood include

field inspection procedures discussed in the remainder of this section and in

table 6, and the more detailed assessment procedures listed in appendix D.2.

3.4.2 Problems Affecting Wood Components

Common problems affecting the strength of structural timber are as follows:

A. Moisture Degradation [1, 2, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]

In relatively dry climates with moderate temperatures, where wood is protected

from deteriorating influences, the mechanical properties of wood show little

change even after several centuries of aging. However, the strength of wood

subjected to high moisture conditions can be adversely affected. The physical

action of take-up or release of moisture causes swelling or shrinkage which

can cause warpage, checking, and/or splitting, all of which have an effect on the strength of wood.

Moisture in sufficient quantity to damage wood can arise from: (a) external

sources such as ground moisture and wetting from rain, and (b) internal

sources such as high relative humidity, or moisture related to building occu- pancy (e.g., leaking pipes). Decay due to excessive moisture can result in

various types of rot, mold and fungi growth.

B. Temperature Effects [1, 11, 12, 13, 14, 15, 17, 20]

The strength of wood increases as the temperature is cooled below 20°C (68°F),

and it decreases as the temperature is raised above this point. This temperature effect is immediate and is dependent on the moisture content of the wood.

When wood is exposed for prolonged periods to high levels of moisture and heat

(65°C or 150°F), thermal decay and related problems (such as fungus, insect

infestation, etc.) are likely to reduce the strength of the wood.

C. Insect Damage [11, 13, 14, 15, 18, 20, 23, 24, 25, 26, 27]

This can occur in seasoned or unseasoned lumber, as well as in standing trees

and logs. Generally, insect infestation is most predominant in geographical

areas that are conducive to high moisture and warm temperature and, particularly, when there is a wood/soil contact condition present. There is no positive method for determining the amount of reduction in strength attributable

to insect damage just from the appearance of the wood. When structural

23
strength is a concern, the safest procedure is to replace all pieces of

wood containing evidence of insect infestation.

The three major types of insects which attack wood are termites, power-post

beetles, and carpenter ants. The most common areas where termites are found are in: (1) warm, moist, soil that has an abundance of cellulose derivatives,

(2) poorly ventilated spaces below the first floor of a building, (3) areas

of wood in contact with the soil, and (4) soil near walls of heated basements.

Power-post beetles are found in humid locations, especially near the ground.

Their presence can most readily be determined in wood by irregular burrows made

by the larvae, while the surface shows only small diameter holes. The presence

of carpenter ants is manifested by piles of chewed wood resembling coarse sawdust outside the wood and by the hollow, irregular, clean chambers made

in wood.

D. Chemical Degradation [1, 11, 12, 13, 14, 15, 18]

Wood is generally resistant to mild acids and solutions of acidic salts.

Some chemical solutions, however, may react with the chemical constituents

of wood and cause a reversible swelling or irreversible changes in the wood

to occur. One of the most common evidences that chemical degradation is

taking place in wood is surface discoloration which occurs as it is exposed

to the atmosphere and ultraviolet radiation. The chief means of combating

chemically degrading forces is to coat the wood with preservatives, water

repellants, or paint coatings.

3.4.3 Preliminary Evaluation of Wood Components

The on-site investigation conducted at the preliminary evaluation stage

(figure 1) will provide information concerning the size, strength, grade, and

extent of surface decay of structural timber in existing buildings. A useful

aid for evaluating structural timber is the grade mark stamped on it at the

mill. Because grade marks usually can be related to a recommended design

value (by reference to the National Design Specification for Wood Construction,

or other relevant documents), it is helpful in determining the quality and

strength properties of the existing timber structure of a building if they can be discerned. If the grade marks are not discernible, it may be necessary

to engage an evaluator who is experienced in identifying and grading wood

products to make the evaluation of the quality and strength properties of

the in-situ structural timber.

Table 6 summarizes the on-site inspection techniques for wood.

3.4. 3.1 Guidelines for Visual Inspection

Visual inspection can provide information on the extent of decay in wood

components. As discussed in section 3.4.1 decay can be the result of fungus

or insect infestation, extreme weathering, or moisture accumulation. Characteristics of decay to be noted in different types of structural components

are given in the following table:

24
Component

Siding

Foundations

Roof s

Porches

Characteristics of Decay

Abnormal coloring (deeper than normal brown color);

cubical checking (indicates an advanced stage of

decay); bleaching (with or without the presence of

fine black lines); softening (especially where

siding ends butt against trim or each other).

Fanlike growth of fungi (located between subfloor and

finish floor, and between joists and subfloor).

Cubical checking, warping, softening, shredding,

breakage (location of all these deficiencies may be on the underside of roof sheathing).

Same as siding (check especially concavely worn areas

that may trap water).

Windows and Brown or black discoloration near joints. Stain on

Doors sash (from condensation). Softening and mold growth

(from accumulation of condensate).

Visual inspection will yield a good overall idea of the in-situ condition of

wood and is the preliminary step in further evaluation of a member's strength

properties. Any additional inspections should include an assessment of the

wood member's internal stability. When conducting a visual inspection, keep

in mind that this is a subjective test, and the accuracy of the results will

depend completely on the skill of the inspector.

During the visual inspection, the following significant structural aspects

should be checked or considered:

A. Inspect carefully for a sag in the wood roof structure. Especially,

attempt to examine the rafters, purlins, collar beams, and ridge boards.

Where applicable, check the condition of the roof boards from inside the

building.

B. All existing dead and live loads on the wood roof structure should be

summed to determine the accumulative existing loads and to determine

whether the additional loads imposed by the retrofit solar components

can be supported by the existing wood framing of the building. The

design capacity of the affected components of the existing wood frame

should be checked with the respect to snow, ice, and wind loads for the

local geographical area, as well as the dead loads for the roofing

materials.

C. Wherever possible, new columns or equipment supports should be placed

directly over existing columns. Therefore, the interior of the building

should be inspected to determine whether there are any conditions which

would prevent this from being accomplished.

25
3.4. 3. 2 Visual Stress Grading [1]

Visual stress grading is simply an attempt to place stock lumber in broad

categories of anticipated load bearing capacities. The lumber usually is

rated into classifications of 40, 50, 65, and 75 percent of the strength of

perfect timber. Obviously, the various grades are earmarked for varying

uses according to their strength rating. The characteristics that determine

a visual stress grade include size and frequency of knots, slope of grain,

and wane. Visual stress grading yields an approximate, conservative estimate

of a member's strength. This is because there is no allowance made for

specific gravity of the wood, and only the surface is available for

inspection.

The advantage of visual stress grading is that it is a fast and easy method

for obtaining a general idea of in-situ timber quality. A disadvantage is

that an experienced evaluator is required.

3.4. 3.3 Manual Probing [19, 28, 29]

Prodding or probing a suspected piece of decayed wood with a sharp tool and

observing the resistance to marring gives an idea of the stage of surface

decay. A loss of hardness can be determined by comparison with sound wood

of the same stock and species. Sound wood tends to lift out of the stock as one or two long silvers with splintery breaks when jabbed with a pointed tool.

Decayed wood tends to lift out and break off squarely across the grain with

little splintering and little resistance.

Manual probing will yield an accurate assessment of in-situ surface conditions,

but it must be used in conjunction with another test method to determine the

internal quality. The probing method is best suited to framework, siding, and

fences. Penetrometers often are used to determine the quality and uniformity

as well as strength properties of wood.

3.4.4 Wood Problems and Potential Impact on Solar Retrofit

A checklist (table 7) can be used to assist in determining what problems

exist in the wood system of an existing building and to make a preliminary

determination of the impact that the problem may have on the solar retrofit.

26
TABLE

6.

TEST

METHODS

FOR

WOOD • •d •

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27
TABLE

7.

PRELIMINARY

ASSESSMENT

CHECKLIST

(WOOD)

28
TABLE

7.

PRELIMINARY

ASSESSMENT

CHECKLIST

(WOOD)

-

(CONTINUED)

29
TABLE

7.

PRELIMINARY

ASSESSMENT

CHECKLIST

(WOOD)

-

(CONTINUED)

30
TABLE

7.

PRELIMINARY

ASSESSMENT

CHECKLIST

(WOOD)

-

(CONTINUED)

31
3.5 MASONRY SYSTEMS

3.5.1 General

Since many of the existing buildings being considered for solar retrofit are constructed of masonry, it becomes important to know how to evaluate the con- dition of the masonry and to determine whether it is capable of supporting

the loads expected to be imposed by the retrofit solar equipment. This is

especially true of load bearing masonry assemblages which are expected to

support: (1) heavy loads (such as water storage tanks, rock beds, absorption

chillers, etc.), (2) dynamic or vibrational loads from rotating or reciprocating equipment, or (3) changes in type of live loads caused by the rehabilitation of the building (e.g. , change in occupancy). As used in this

discussion, masonry is broadly defined to include products such as hollow and

solid masonry units, gypsum masonry, glass masonry, natural building stone,

adobe block, clay building bricks, concrete block, and structural clay tile.

3.5.2 Preliminary Evaluation of Masonry

As shown in table 8, there are several field inspection techniques discussed

in this section which can provide useful information on surface properties of

masonry (flaws, discoloration, cracks, etc.), deficiencies in mortar joints,

differential structural movement, dimensional characteristics, and location

and uniformity of inner cell grout. More detailed assessment procedures are summarized in appendix D.3 for determining masonry properties (e.g., com- pressive or diagonal tensile strength, location of steel reinforcement,

flexural bond strength, moisture content, modulus of elasticity, chemical

resistance).

3. 5. 2.1 Visual/Optical Inspection [30, 31, 32, 33]

Visual/optical inspection methods usually are the least expensive and most

commonly used means of detecting surface flaws in masonry construction.

Defects (such as surface cracks in bed mortar or at bonded interfaces, nonbonds, missing or defective mortar, erosion, corrosion, misalignment, etc.)

most often can be detected with the naked eye. With the use of optical

magnifiers, very small surface defects (as small as only a few microns wide) can be detected.

Visual measurement can be used to determine the size and/or warpage of masonry

construction. Either a steel scale, a gauge or caliper, or a steel measuring

wedge can be used to determine the size and warpage of the masonry units.

Using binoculars, focus on areas of the roof that are particularly subject to

leaks (e.g., joints between converging slopes and around chimneys, exposed

flashing, gutters, downspouts, etc.). Especially look for areas where mortar

appears to lighten in color (an indication of patching), or where mortar

appears to be crumbling. Also, scan the exterior wall of the building for

any obvious signs of bulging in the brick (especially near the bottom of the

wall or near openings. These bulges usually are an indication that the mortar

32
has failed or (in the case of brick veneer) that the ties between the veneer

and the structure of the building have deteriorated.

Inspect visually for horizontal cracks in the middle of a basement wall. If

the cracks are accompanied by obvious inward bulging, this indicates excessive

pressure being exerted by the soil outside the wall which could be caused by

excessive ground-water pressure or by compaction from adjacent new construction work. Vertical cracks located in a corner of the basement that widen

to 6.35 mm (1/4 in) or more at the top often are caused by a settling footing

beneath the foundation. Any of these types of cracks could jeopardize the

structural Integrity of the entire basement wall.

During the visual/optical inspection, the following significant structural

aspects should be checked or considered:

A. Check for soft and crumbling mortar in masonry foundation walls. This

condition could be serious if it is associated with any signs of sag in

the structure.

B. Masonry foundation cracks usually are diagonal, starting from the top,

the bottom, or the end of the wall. If the cracks do not extend to at

least one edge of the wall, they probably are not caused by foundation

problems. It is important to determine the cause of these problems and

remedy the situation because the addition of retrofit solar equipment

loads on the building could aggravate the problem further.

C. When new heavy loads are expected to be added to the existing masonry

foundation, it will be necessary to check it for structural adequacy.

If details of the masonry foundation design and the soil bearing value

cannot be determined from existing drawings and reports of subsurface

soil investigations, it may be necessary to: 1) excavate adjacent to an outside wall to determine the type of existing foundation, and 2)

conduct a subsurface soil investigation (soil borings). Results from

the subsurface soil investigation can be used to support the need for new foundations under heavy loads or to prove the adequacy of existing

foundations.

D. All existing dead and live loads on the roof structure and affected

masonry supporting walls should be summed to determine the accumulative

existing loads and to determine whether the additional loads imposed by

the retrofit solar component can be supported by the existing masonry

structure. The design capacity of the affected components of the masonry

structure should be checked with respect to expected snow, ice, and wind

loads for the local geographical area, as well as the dead loads of the

roofing materials.

E. Whenever possible, new columns or equipment supports should be placed

directly over existing columns. Therefore, the interior of the building

should be inspected to determine whether there are any conditions which

would prevent this from being accomplished.

33
3. 5. 2. 2 Hammer Test [34]

The hammer test is an inexpensive and unsophisticated method of estimating

the condition of a masonry unit or assemblage by the sound that it produces

when tapped lightly with a hammer. Although the results are questioned by

many evaluators, some very experienced people (who have a keen sense of

hearing and touch) claim to have the ability to determine the structural

soundness of masonry units and mortar and to determine whether the cells of

the units are filled, by the use of this test method. Experience and credibility on the part of the evaluator is required, however, before any degree

of reliance should be placed on the interpretation of the results. Even

then, it may be desirable to use test borings to confirm the findings.

3. 5. 2. 3 Probing [34]

The location and uniformity of the inner cell grout and wall thickness of a masonry unit or assemblage can be determined by penetrating the area of

investigation with a small masonry drill bit and probing the hole with a stiff

wire. Small holes may be patched easily leaving only minor surface damage.

Probe the mortar joints with an awl or ice pick to determine whether it is

soft and sandy or falls out easily.

3. 5. 2. 4 Ink Test [35]

Using permanent blue-black fountain pen ink, it is possible to estimate the

imperviousness and opacity of ceramic glazed facing tile, brick, and solid

masonry units. To test for imperviousness, the ink is applied to the glazed

surface of 5 dry specimens for 5 minutes. The surface then is washed and

examined for stain of the finish. Opacity may be determined by applying the

ink along a 50 mm (2 in) length of the edge of the finished surface. After

5 minutes, the finish is examined visually for opacity. ASTM C 126 describes

these two tests in greater detail.

3.5.3 Problems Affecting Masonry Components

Some of the most common problems affecting the strength of masonry units or assemblages used in building construction are as follows:

A. Cracking [31, 33]

Cracking usually is not an indication that a building is becoming structurally

unsafe. It is normal therefore to find some cracking in the masonry of

almost every building. In fact, it is very rare for a building to collapse

soon after the appearance of even large cracks.

Cracks usually result from forces being applied to the building which are greater than the loads for which the building was designed. These loads may

include

:

34
1. Overloading due to excessive external forces such as snow, wind, etc. or internal forces such as heavy equipment loads, change in occupancy

loads, etc.

2. Forces induced by temperature changes causing differential movement

of the building materials.

3. Ground movement (subsidence, slippage, shrinkage, or quakes) causing

part of the building to become displaced from the rest of the

building.

4. Changes in moisture content of the masonry materials. This can lead

to chemical reactions (such as corrosion of the reinforcement or sulphate attack on Portland cement) or volume changes (swelling or shrinkage).

5. Atmospheric pollution such as carbon dioxide attack which causes carbonation of Portland cement and subsequent shrinkage.

B. Spalling

As used in this report, spalling is a chipping or scaling of the surface of

masonry similar to the same effect in concrete. Often, it is caused by

vibrational, impact, or shock loads.

C. Deterioration

Deterioration is described in this report as a break-down or disintegration

of the material properties of masonry. A typical example is the softening

(or crumbling away) of the matrix in the brick or mortar due to chemical

attack.

D. Moisture

Moisture can be a problem in itself (causing swelling or shrinkage of the

masonry), or it can be the cause of other problems previously mentioned

(cracking, spalling, or deterioration).

All of these problems can have a serious detrimental effect on the structural

integrity of the masonry units or assemblages and should be investigated

thoroughly to determine whether they significantly limit the addition of the

proposed solar retrofit equipment.

3.5.4 Masonry Problems and Potential Impact on Solar Retrofit

A checklist (table 9) can be used to assist in determining what problems

exist in a masonry structure and to make a preliminary determination of the

impact that the problem may have on the solar retrofit. If it is determined

that a more complete understanding of the nature or cause of the problem is

necessary, further reference is given in the table to a more detailed

description in appendix D.3.

35
TABLE

8.

TEST

METHODS

FOR

MASONRY

36
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

37
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

-

(CONTINUED)

38
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

-

(CONTINUED)

39
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

-

(CONTINUED)

40
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

-

(CONTINUED)

41
TABLE

9.

PRELIMINARY

ASSESSMENT

CHECKLIST

(MASONRY)

-

(CONTINUED)

42
3.6 METAL SYSTEMS

3.6.1 General [36, 37]

Flaws in the steel structure of a building are not as subject to fatigue

(from cyclic vibrations, etc.) as flaws in other structures (such as bridges).

Therefore, it may not be critical to evaluate them in relation to their

ability to support new solar equipment loads.

If, however, it has been determined that a structural component (weldment,

splice plate, etc.) is suspected of degrading the structural integrity of the

building, nondestructive evaluation methods can be extremely useful. As a result of improved techniques, these test methods are becoming increasingly

more important for evaluating the metal structure of buildings. It is

important, to evaluate other flaws than cracking. Corrosion, voids, pits,

fabrication discontinuities, and porosity can affect structural integrity

and the ability of the existing structural system to support new solar

retrofit equipment.

Most nondestructive test methods offer more than a superficial examination

of the surface conditions of metals. Such tests may reveal properties,

quality, and dimensions of both the surface and internal regions of many

metal test specimens.

Although most of the test methods for metals mentioned in this report will be

used primarily for structural steel, many are applicable to other types of

ornamental and structural metals (e.g. , cast-iron, aluminum, etc.) as indicated

in the summary tables in this section and in section D.4 (detailed evaluation

methods).

Usually, the most important factors of structural steel to determine are:

1) dimension, 2) type of steel, and 3) the age of the steel in order to

determine its strength.

Factors to consider in selecting an appropriate nondestructive test of metals

are:

1) What is the material to be tested?

a. Is it magnetic or nonmagnetic?

b. Is it electrically conductive?

c. Does the metal have a nonconductive or nonmagnetic coating?

An easy method to determine whether a structural member is made of wrought

iron or steel is to apply dilute nitric acid to a clear section. If the

member is made of steel, the test section will turn black; whereas, the

wrought iron will not be affected.

2) How was the metal fabricated (cast, wrought, powder metallurgy,

welded, soldered, etc.)?

43
3) What is the geometry of the component (dimensions, shape, surface

irregularities etc.)?

4) What types of defects are possible or expected in this type of metal?

5) What degree of sensitivity and resolution is required from the test

eq uipment?

6) What are the equipment, testing, and materials costs?

7) How accessible is the component (e.g. , behind a wall; concealed by

ductwork, etc.)?

There are several on-site testing methods which can be used during the

preliminary evaluation stage (figure 1). These can provide useful

information concerning surface defects (cracks, voids, fabricating discontinuities, pits, poor bonding, porosity, laps, seams, and other irregularities). Some of the most commonly used are included in the following table.

Other methods which are part of the detailed evaluation stage, are summarized

in appendix D.4 and can be used to assist in determining additional properties.

3.6.2 Preliminary Evaluation of Metal Systems

Several preliminary evaluation procedures exist to determine the surface

properties of metal structural components. It should be realized, however,

that these test methods have limited application in that they do not provide

information on the internal physical condition of the metal structural member.

In order to obtain an estimate of the internal condition and the strength of

the metal, the more complex test methods described in appendix D.4 will have

to be used.

As with the other structural materials, the most important areas to investigate

are the areas of high shear and low moment. It is at these stress points

where the defects and structural failures are most likely to occur. Therefore,

the investigator should concentrate on inspection of these particular areas of concern.

3. 6. 2.1 Visual Inspection

Visual inspection is the least expensive and most commonly used means of

detecting surface flaws in metal construction. Surface flaws (such as cracks,

voids, fabricating discontinuities, pits, poor bonding, porosity, laps, seams,

etc.) usually can be detected using simple visual inspection techniques.

During the visual inspection, certain instruments (such as borescopes, fiber

optical equipment, panoramic cameras, etc.) can be used to examine areas of

the metal which are inaccessible to the naked eye. Simple magnifiers can be

used to detect flaws which are too small to be seen by the naked eye. During

this inspection, the following significant structural aspects should be

checked or considered:

44
A. If the existing roof is composed of a steel deck on steel joists, and new heavy concentrated dead loads are to be imposed on the deck by solar

equipment, the joists must be designed for twice the static operating

weight of the equipment. Also, there must be enough room to reinforce

the top chords of the joists for any new concentrated loads which may be

applied between panel points. Since any new concentrated loads which

must be applied to the bottom chords will have to occur at panel points, access to these points is essential. Existing joists should be checked

to be sure they can support newly imposed loads wthout exceeding a maximum

deflection of 1/360 times the span.

B. Wherever possible, new columns or equipment supports should be placed

directly over existing columns. Therefore, the interior of the building

should be inspected to determine whether there are any conditions which

would prevent this from being accomplished.

C. All existing dead and live loads on the metal roof structure should be

summed to determine the accumulative existing loads and to determine

whether the additional loads imposed by the retrofit solar components

can be supported by the existing metal structure. The design capacity

of the affected components of the metal structure should be checked with

respect to expected snow, ice, and wind loads for the local geographical

area, as well as the dead loads of the roofing materials.

3.6.3 Table No. 10 has been developed to assist the evaluator during the

visual inspection to determine the possible causes of problems encountered

and to realize the impact that they may have on the proposed solar retrofit.

45
TABLE

10.

PRELIMINARY

ASSESSMENT

CHECKLIST

(METALS)

46
TABLE

10.

PRELIMINARY

ASSESSMENT

CHECKLIST

(METALS)

-

(CONTINUED)

47
TABLE

10.

PRELIMINARY

ASSESSMENT

CHECKLIST

(METALS)

-

(CONTINUED)

48
4. GUIDELINES FOR HEATING, VENTILATING AND AIR CONDITIONING (HVAC) SYSTEMS

This section provides methods for evaluating existing building HVAC systems

being considered for solar retrofit. These methods are intended for use in a feasibility study to help determine whether the existing HVAC systems are suitable for solar retrofit. The data and information obtained will be

valuable also for the final design of the proposed retrofit solar and HVAC

system. This evaluation is developed in two stages: (1) preliminary information derived from reasonably unsophisticated procedures, and (2) secondary

information derived from more detailed or sophisticated procedures. This

section covers the preliminary evaluation only. The secondary or detailed

evaluation is contained in appendix D.5.

4.1 GENERAL CONSIDERATIONS

Some solar energy systems can be retrofitted into existing buildings to

supplement energy demands for space heating, space cooling, and ventilation

preheating. In general, the temperature levels in solar energy systems are lower than those commonly found in fossil fuel HVAC equipment. Also temperatures tend to fluctuate as the availability of solar energy varies. Consequently, greater care is needed in evaluating existing systems and in

designing a solar system for an existing building. For example, properly

oriented space will be required on the roof for solar collectors. Additional

(or replacement) heat exchangers, pumps and blowers will be needed also,

together with appropriate heat storage equipment, piping, ducting, and controls. Unless the existing HVAC equipment is in good condition, of suitable

capacity, and adapted to solar retrofit, a solar system may not be feasible.

This section does not cover the solar design, but concentrates on methods

for evaluating the existing HVAC systems and equipment. The evaluation will

be based on information obtained from building system records, examination

of the HVAC equipment, and measurement of system performance. Forms for

collecting data are included in appendix A, and were discussed in section 2.1.

4.2 PRELIMINARY ON-SITE INVESTIGATION GUIDELINES - HVAC SYSTEMS

The on-site investigation of an HVAC system consists of a general examination

of the entire HVAC system as well as the individual HVAC components (air

handlers, ductwork, etc.). While the emphasis should be on the HVAC components which may be affected by the solar retrofit, the entire system becomes

involved where additional HVAC loads or modifications are anticipated or where

load reductions occur as a result of energy conservation measures taken.

The following general inspection guidelines will be useful in making the

preliminary assessment.

4.2.1 Utility Bills

Energy consumption of a building can be determined from the utility payment

records of the past several years. This history of energy usage will establish a base line for a life-cycle analysis. Figure 3 provides a format for

recording annual energy consumption.

49
FIGURE 3 [7]

Jan

Feb

March

April

May

June

July

Aug

Sept

Oct

Nov

Dec

HISTORIC ENERGY CONSUMPTION RECORD

For Year 19 , Annual Degree-Day

Electricity

(Kw) ($)

Natural

Gas

( The rms ) ( $ ) Fuel Oil

(Gallons) ($)

Total

(Use separate sheets if different components of the HVAC system are metered

separately. This helps to estimate the loads on each components).

50
4.2.2 Operating and Maintenance Records

Operating and maintenance records covering the HVAC equipment will provide

information such as: (1) equipment repair and replacement costs, (2) number

of times the equipment was out of service, (3) frequency and nature of user

complaints, and (4) changes in the functional use of building space. For

example, complaints from occupants may provide clues concerning inadequate

ventilation or uncomfortable temperatures, which may indicate inefficient

system performance or demands which have outgrown the capacity of existing

equipment. Repeated repairs or frequent replacement of equipment may indicate that the existing system is not worth retrofitting. A consulting

engineer can help the building facilities engineer to interprete the

operating and maintenance records.

4.2.3 Visual Inspection of HVAC System

Visual inspection of the HVAC system is essential where the original

construction drawings and specifications are either no longer available, or

if available, the HVAC system has been significantly modified or enlarged.

Such an inspection may reveal that solar retrofit should not be considered

because the existing system is obsolete, inadequate for the present load, or

is not economically feasible with present equipment or fuels. Moreover, an existing HVAC system which is approaching or has exceeded its expected service

life is generally not a candidate for solar retrofit. It may, however, be a good candidate for solar replacement.

4.2.4 Visual Inspection of HVAC Equipment

In evaluating the HVAC equipment, it is important to obtain as much data as possible. The nameplate data for each piece of equipment, including pumps,

blowers, air handlers, terminal units, compressors, etc., should be recorded,

and each piece of equipment should be evaluated with regard to age, condition

and potential performance output. Even though some of the equipment is old

or out of production, local dealers, the original manufacturer, or professional

engineers within established local HVAC engineering firms may be able to

provide an assessment of such equipment.

Figure 4 provides a form which will assist in conducting a visual inspection

of the HVAC system and its existing equipment. Some specific matters which

need to be covered include: [38]

1. Determine whether the heating plant was originally designed to burn

coal. If it was, then it probably is more than 30 years old and

may be a good candidate for replacement.

2. Test the heating system. Even on a hot day, it can be tested by

moving the thermostat above room temperature. Heat from a hot-air

furnace should appear at registers within a few minutes. In a steam

or hot-water system, radiators should heat up in 15-20 minutes.

51
FIGURE 4. EXISTING HVAC DESIGN IDENTIFICATION [7]

Identification

Estimated Air & Water Temperature Range

Estimated

Equipment Age

Btu

Output

Range

Residential

Non-Re sidential

Forced Air System

Radiant System

Water

Steam

Electric

Natural Convection

Steam

Hydronic

Electric

Unitary

Number of Control

Zones

Terminal Units

Constant Air Volume

(CAV)

Variable Air Volume

(VAV)

Fan Coil

Induction Terminal

Perimeter Baseboard

Distribution Systems

All Air Systems

CAV

VAV

Single Path

Dual Path

Multizone

Air and Water Systems

Two Pipe

Three Pipe

Four Pipe

All Water Systems

Two Pipe

Three Pipe

Four Pipe

Heat Pump Systems

Air to Air

Water to Air

Water to Water

52
3. Determine or estimate the capacity and condition of the domestic hot

water heater.

4. Look for signs of leaks or rust spots around and on the bottom of

the hot-water heating tank, especially where a gas flame impinges.

5. On steam or hot water heating systems, examine floor around radiators

and convectors for signs of stain or rot from water leaks.

4.2.5 Space Considerations for HVAC Equipment

During the inspection tours in the existing mechanical rooms, note and record

all available space for potential future installation of solar heating and

replacement equipment. Photographs should be taken of the area available for

the use of a prospective solar designer.

Appendix D.5.2.9 provides schematic drawings of typical solar heating systems.

These should be examined to determine whether overall space is available or can be provided for such systems. In particular, space will be required for

heat storage units, pumps, air handlers, and heat exchangers. The building

facilities engineer should be able to provide the prospective system designer

with photographs and dimensional sketches so that a decision can be reached

concerning the availability of space for a particular retrofit.

In addition, where existing equipment may need to be replaced, consideration

must be given to such required space. For example, if new heat exchangers

are anticipated, the facilities engineer must check the adequacy of the

existing space to accommodate them. A U-tube heat exchange may be required

for some spaces (rather than a straight-tube type) if access is limited to

only one side for cleaning or replacing the tubes.

4.2.6 Furnace/Boilers /Heating Systems [38, 39, 40, 41]

The current trend toward energy conservation and subsequent reduction in

heating loads in buildings has had an effect on the efficiencies of furnaces

and boilers. Older units tend to be oversized and often yield lower efficiencies. In such cases, a replacement may be desirable. Before such a decision is made, several actions should be taken to evaluate the efficiency

of the existing heating components. The combustion system should be cleaned

carefully and checked for leaks. The air should be allowed to enter the

combustion chamber at controlled rates. The oil nozzle size may need to be

reduced or the gas burner may need to be replaced if the system is to

accommodate a replacement.

The required air-fuel ratio should be determined for the existing or replacement system, and adjusted for proper combustion. The 0£ and CO 2 content may be determined with an Orsat apparatus or with other flue gas analyzers such as the nondispersive infrared spectrometer for carbon dioxide,

or by utilizing oxygen-specific electrodes to determine oxygen. These,

coupled with the stack temperature readings, will provide data for determining

53
the system combustion efficiency. The final decision on system replacement

generally is made on the annual operating savings that can be expected as a result of purchasing and installing a new system.

The above procedure provides only steady-state information, whereas in reality,

most systems operate far from steady-state. Nevertheless, a combustion performance test should be undertaken whenever major retrofits of a building

are planned in order to obtain hands-on operating experience and an immediate

sense of condition of the furnace or boiler and other components of the HVAC

system. The person carrying out this condition assessment should be technically experienced so that any decision made for replacement of furnace, boiler, or components is based on qualified information.

4.2.7 Evaluation of Amount of Air Leakage through the Building Envelope,

Utilizing Pressurized Air [42, 43, 44, 45]

In general, simple conservation measures (such as the reduction of building

air leakage) are more cost effective than solar retrofit measures and should

be investigated first. Uncorrected heat losses can seriously reduce the

potential gains to be expected of a solar retrofit system.

Pressurization of the space within a building, either positive or negative

with respect to atmospheric pressure, is one means of gaining a quantitative

measure of the air leakage of a structure. A fan, a metering station to

determine air flow rate, and pressure sensors, along with temperature measurements, are needed to make the determination of leakage rate for a given pres- sure differential. Generally, a window or door opening can be fitted with a plywood partition through which the air required to pressurize the structure

is introduced. The pressurized air will seek points of penetration, in an effort to equalize the pressure between the space and the surrounding atmosphere. The amount required to maintain the pressure differential provides

an indication of the overall air leakage performance of the structure. It is

possible to isolate major points of leakage by selectively taping cracks and

joints during a sequence of tests. Internal air leakage paths can be identified using a fan to generate differential pressures and an infrared scanner

to trace the path through the construction (see paragraph 4.2.8 below).

This technique is rather simple and not necessarily expensive (expense will

vary with the complexity and detail of measurements). The results of the

air pressurization test will not necessarily indicate the rate of infiltration obtained under natural (unpressurized) conditions, but, they do provide

a relative measure for determining whether the structure is leaking excessively.

Consult references [45] and [46],

4.2.8 Determining Paths of Leakage Using Thermography [47, 48, 49]

Sources of high heat losses can be determined through the use of thermography.

This is a technique for "seeing" thermal energy radiating from the surface of a heated object. The infrared energy radiated from the object is displayed

on a cathode ray tube. If a black and white cathode ray monitor is used, the

intensity of the gray scale is proportional to the temperature of the object.

54
Within a given range, colder objects appear dark and hotter objects appear

light. If a color monitor is used, the gradation of colors (red, green,

blue) of the image indicates the surface temperature variations. Thus, areas

of heat leakage may be detected by observing the building surface temperatures

A photograph record can be taken of the image on the screen of the monitor

and surface temperatures may be inferred from the thermal image.

4.2.9 Measurement of Air Flow Rate in Air Distribution Systems by the

Velocity Head Method [7]

Velocity head is measured by placing a pitot tube directly in the air steam

in a duct. This should be done at several locations in the duct cross-section

each location being the center of an increment of equal area in the duct.

Rectangular ducts should be divided into 12 or more incremental areas, and

large round ducts into equal concentric areas, four measurements being taken

within each quadrant. Pitot positions are shown in figure 5 for both

rectangular and round ducts. For small, round, ducts such as 127 mm (5 in)

branch ducts in a residential heating system, one velocity head measurement

may be taken at the center of the duct. The average velocity is taken to be

90 percent of the centerline velocity, and the flow rate is computed using

the average velocity.

Instructions are provided with the pitot tube and manometer equipment for

converting velocity head to air velocity. Some manometers read directly in

velocity. All of the velocity readings at one duct position are averaged to

get the final average duct velocity. The air flow rate in a round duct of

diameter, D-^ nc^es , for an average velocity, VaVg, is calculated as follows:

V D

2

ACFM = av§ x

, (actual cubic feet per minute).

183.35

The air flow rate in a rectangular duct with inside dimensions of A and B inches becomes:

A x B x V

ACFM = a 144

The measured flow rate can be converted to flow rate at standard conditions

(SCFM) as follows:

SCFM = ACFM x ADR, (standard cubic feet per minute)

55
PITOT TUBE MEASUREMENT LOCATIONS FOR

RECTANGULAR AND LARGE ROUND DUCTS

FIGURE 5 [7]

56
where ADR (air density ratio):

530

(460 + T) exp (ALT)

^ 27,000

and

T = air temperature (°F) during measurements

ALT = site elevation (ft MSL) relative to mean sea level

exp = exponential, or e^lt/^jOOO)

4.2.10 Measurement of Air Flow Rate by Pressure Rise Across the Supply

Blower [7]

Air flow may be determined by measuring the pressure rise across the blower,

using a manometer and two static pressure probes. One probe should be placed

near the blower inlet, and another down stream from the blower discharge, in

a straight, constant area section of the discharge duct (see figure 6).

Some fan manufacturers specify where static pressure measurements should be

taken. 1

Estimated air flow rate in cubic feet per minute (CFM) may be determined from

the manufacturer's blower performance characteristics curves for any given

operating condition, consisting of: 1) discharge air temperature, 2) measured

blower revolutions per minute (rpm), and 3) static pressure rise differential

(or rise as determined above). See appendix D.5.2.6. Air flow at standard

air conditions then may be obtained by using the conversion formula in

paragraph 4.2.9 above.

4.3 HVAC PROBLEMS AND POTENTIAL IMPACT ON SOLAR RETROFIT

Table 11 is a checklist of typical problems for an existing HVAC system.

For each problem listed, the tabulation offers possible causes, and the

impact which the problem may have on a proposed solar retrofit.

57
TABLE

11.

PRELIMINARY

ASSESSMENT

CHECKLIST

(HVAC)

58
TABLE

11.

PRELIMINARY

ASSESSMENT

CHECKLIST

HVAC

-

(CONTINUED)

59
AIR

FLOW

O x

BLOWER STATIC PRESSURE TAP LOCATIONS

FIGURE 6 [7]

60

-

PROPER

BLOWER

STATIC

PRESSURE

TAPS

-

IMPROPER

STATIC

PRESSURE

TAPS
5. GUIDELINES FOR PLUMBING SYSTEMS

The existing plumbing system in the building should be evaluated to determine

its adequacy to support system additions or modifications resulting from a solar retrofit. This includes the water supply and drain-waste-vent (DWV)

components. This section provides guidelines for the preliminary evaluation

of the plumbing system. See appendix D.6 for further information to accomplish

a more detailed assessment of the system.

5.1 GENERAL CONSIDERATIONS

Plumbing DWV and water supply systems can become major problems in building

rehabilitation. Modification of these systems when considering solar retrofit

often lead to extensive additional structural and finish work. This is

because:

1. The plumbing system in an existing building may not comply with the

requirements of current local codes and standards, and also may

need additional equipment to meet the load imposed by added solar

equipment.

2. The installation of new piping, vents, etc., required for solar

equipment may be constrained by the space available and the existing

piping configuration.

3. The methods of connecting new plumbing to the existing system can cause problems relative to materials and construction techniques.

5.2 ON-SITE EVALUATION GUIDELINES - PLUMBING SYSTEMS

The on-site investigation of the plumbing system consists mainly of a general

examination of the plumbing components. While the emphasis should be on the

plumbing components which may be affected by the solar retrofit, it is necessary also to make an overall review of the condition of the entire plumbing

system. This is especially important where additional plumbing loads or significant modifications are anticipated.

5.2.1 Operation and Maintenance Record Examination

The operation and maintenance records for the past several years should be

examined, and any complaints of leaks, clogging, sweating, air hammering,

etc., should be noted and analyzed. Any existing additions or modifications

to the plumbing systems should be noted on the construction as-built

drawings if they are available. This examination should provide information

concerning the adequacy of the existing plumbing system which, in turn,

will assist in making the decision regarding a proposed solar retrofit.

61
5.2.2 Visual Inspection of Existing Plumbing System [38, 50, 51, 52, 53,

54, 55]

A thorough inspection of the plumbing system should be carried out by a qualified plumbing inspector to gain a professional opinion on the ability of

the system to function in a satisfactory manner and for compliance with the

local code. Physical inspection should include observations regarding the

following matters:

1) Conditions which could cause an unsafe building environment:

a. Excessively hot water (inadequate performance of temperature control

devices)

.

b. Explosion hazard due to inadequate temperature and pressure limiting

devices.

c. Plumbing wall construction which could allow fire spread and passage

of smoke or toxic gases in case of a building fire.

d. Water or drainage leaks, including leaks around fixture connections

which could result in deterioration of structural elements or materials.

2) Conditions which could cause an unsanitary building environment:

a. Leaks in sanitary drains and vents (which can contribute to the

development of vermin, mold, odors, noxious or explosive gases,

sewage accumulation, etc.).

b. Overflowing of sewage from fixtures.

c. Emission of sewer gas or detergent suds from fixtures.

d. Inoperative fixtures.

e. Inoperative domestic water heater, or inadequate supply of hot

water.

f. Poor performance of water closets.

g. Inadequacy of potable water supply.

h. Backflow hazard including absence or malfuction of vacuum breakers

and backflow preventer.

Although the value of inspection may be diminished where portions of the

system are concealed, the personal judgment of an experienced plumbing

inspector can usually be relied upon for an opinion whether the existing

system can be adapted to solar retrofit.

62
5.3 PLUMBING PROBLEMS AND POTENTIAL IMPACT ON SOLAR RETROFIT

The following checklist (table 12) may be helpful for determining the impact

of typical problems on a proposed solar retrofit.

63
TABLE

12.

PRELIMINARY

ASSESSMENT

CHECKLIST

(PLUMBING)

64
TABLE

12.

PRELIMINARY

ASSESSMENT

CHECKLIST

(PLUMBING)

-

(CONTINUED)

65
6. GUIDELINES FOR ELECTRICAL SYSTEMS

This section provides general information for the preliminary evaluation of

the electrical system including its potential impact on a proposed solar

retrofit. Evaluation methods covering circuit faults, insulation deterioration, and circuit breaker condition are listed and discussed. The general

electrical requirements for solar retrofit also are included. Information on the more detailed evaluation techniques for electrical systems is given in

appendix D.7.

6.1 ON-SITE EVALUATION GUIDELINES - ELECTRICAL SYSTEMS

The on-site investigation of the electrical system consists mainly of a general examination of the electrical components. While the emphasis should

be on the electrical components which may be affected by the solar retrofit,

it is necessary also to make an overall review of the condition of the entire

electrical system. This is especially important where additional electrical

loads or modifications are anticipated. If a system is outmoded or is grossly

under capacity to accomodate the power demands of potential solar equipment

(electric booster heaters, blowers, pumps, etc.), solar retrofit may not be

economically feasible. Even though electrical construction drawings and

specifications of the existing building are available, the existing arrangement and condition of the electrical installation should be determined.

Since most electrical wiring is concealed inside the walls, a complete

inspection of all parts of the electrical system in a building may not be

feasible. Some components, however, are easily checked, which will aid in

evaluating the electrical shock and fire safety risks of the system compared

with the requirements of the National Electrical Code and the local code.

Potential problems resulting from system overloads (as new appliances and

oversized fuses are installed) also should be considered.

While the evaluation methods mentioned in this section generally are recognized as being good practice, local codes and local officials should be

consulted to determine whether special requirements apply to the specific

building being evaluated.

6.1.1 Operation and Maintenance Records

Before a building inspection is undertaken, operation and maintenance records

should be examined to identify potential problems. Incidences of power

failure, insufficient lighting, electrical shock, excessive voltage drop, or short circuiting should be noted with respect to the appropriate circuit and

component involved.

6.1.2 Assessing Electrical Branch Circuits [38]

One of the best techniques for assessing the condition of an existing electrical

system is through visual inspection of the wiring system. It helps to determine the condition of the insulating material, as well as the quality of the

connections made. It is important also to evaluate how the system is used

during normal operation. The following items are considered essential:

66
1) Overfusing ~ Check for proper size fuse or circuit breaker in branch

circuits. A fuse of greater capacity than originally designed will

permit a potential overload of the circuit. This could result in a fire hazard.

2) Overlamping - Note the wattage of lamps compared to wattages permitted

for the fixture. This is critical in confined spaces such as recessed

lighting fixtures and may result in ignition of nearby combustibles.

3) Overloaded Circuits - Determine whether the proper size wire and fuses are installed to conform to the local code or to the National

Electrical Code. Make note of spare circuits for potential use with

solar equipment.

Common symptoms of circuit overloading include: (1) an excessive

number of 30 ampere fuses or breakers; (2) the smell of burned insulation within a panel; (3) glass top fuses which are warm; (4) discolored copper contact points under the fuses; (5) overheating of

wires as evidenced by melted or brittle insulation, (6) evidence of

heat discoloration due to fire around outlet boxes, switches, thermal

insulation, etc.; (7) fuses which blow frequently or circuit breakers

which trip frequently; and (8) presence of extensive surface mounted

lamp cord extension wiring and multiple outlet cubes plugged into

single outlets.

4) Type of Wiring - Determine whether the appropriate type of wiring

and connectors have been used.

5) Type and Condition of Insulation - Determine whether the insulation

around conductors is in satisfactory condition. Brittleness, flaking, or cracking are unacceptable, and wiring in this condition must

be replaced. Examine insulation in exposed areas of the basement, in or near circuit breakers or fuse boxes, and inside outlet or switch

boxes. Turn power off before removing outlet or switch plates and

before probing wires.

6) Connectors - Check circuit connectors for excessive heat and power

losses. Look for discolored metal, deteriorated insulation, and

evidence of fire. Resistance losses cause low voltages which can impair appliances and shorten the life of components.

Visual inspection provides valuable information regarding the condition and

adequacy of circuits and components, but only an experienced technician should

conduct the inspection.

6.1.3 Blower Motor Horsepower Measurement [7]

The first step is to obtain the following information from each motor

nameplate:

67
1) Rated motor horsepower

2) Number of phases

3) Cycles

4) Voltage(s)

5) Rated amperes at full load

6) Operating speed(s)

7) Type of motor and serial number

8) Power factor

9) Diagrammed electrical connections

If the motor nameplate cannot be located, obtain the above information from

the manufacturer. It will be necessary to help him identify each motor by

describing its size and appearance, mounting, color, components, number and

location of leads, character of load (type of blower), rotational speed, number

and size of belts and sheaves, and any other such information the manufacture

may need.

The next step is to determine the existing operating motor horsepower (OHP)

using the following nameplate and field test data:

Reading Abbrev. Value

Nameplate HP NHP

Nameplate Volts NV

Nameplate Amperes per phase NA

Measured Operating Volts OV

Measured Operating Amperes per phase OA

Measured No-Load Volts NLV

Measured No-Load Amperes per phase NLA

The above nameplate data may be read directly from the motor nameplate or may

be obtained from the manufacturer as discussed earlier. The remaining data

is obtained by measuring the operating volts and amperes directly at the motor,

using a simple alternating current voltmeter and a snap-on type AC ammeter.

Readings are needed with the motor operating at its existing normal load, and

again with the motor operating while mechanically disconnected from the load.

Using the above data, the existing operating motor horsepower (OHP) may be

calculated from the following relationship:

OHP = NHP (OA - 0.5 NLA/Corrected NA - 0.5 NLA)

where

Corrected NA = NA (OV/NV).

68
The nameplate and measured voltage and current values obtained for the above

tabulation will be affected by the type of power supplied to the motor and

the wiring system. These are discussed as follows:

1) 110 Volt, Single Phase System

There are two power leads connected to the motor; one is hot and the

other is neutral or ground. Measure the operating voltage across

the two leads, and measure the operating current in either lead.

The nameplate voltage and nameplate current should be similar to

these measurements.

2) 220 Volt, Single Phase System

There are three leads or wires connected to the motor, one neutral

and two 110V hot wires. The voltage is measured across the two hot

wires and the operating current is determined by summing the current

measured in both hot wires. The nameplate voltage should be close

to 220 volts, and the nameplate current is approximately double the

measured current in one hot wire.

3) 220V, Three Phase, 3 Wire System

Each of the three wires are 220V hot wires. The operating voltage

is measured between any of these three wires and ground. The

operating current per phase is measured in any one of the hot wires.

The nameplate voltage should be close to 220 volts, and the nameplate current should be approximately three times the measured current

in any one wire.

4) 220V, Three Phase, 4 Wire System

There are three 220V hot wires and one neutral wire. The voltage is

measured between any of the hot wires and the neutral. The current

per phase is measured in any one of the hot wires. The nameplate

voltage should be close to 220 volts, and the nameplate current

should be approximately three times the measured current in any one

wire.

6.2 ELECTRICAL PROBLEMS AND POTENTIAL IMPACT ON SOLAR RETROFIT

The following checklist (table 13) can be used to determine the problems in

the electrical system of an existing building, and to make a preliminary

determination of the impact that the problems may have on the solar retrofit.

69
TABLE

13.

PRELIMINARY

ASSESSMENT

CHECKLIST

(ELECTRICAL)

70
REFERENCES AND SUGGESTED ADDITIONAL READINGS (Nos. 1-76 are references)

1. Applied Technology Council, Tentative Provisions for the Development

of Seismic Regulations for Buildings , SP-510 (Washington, D.C.:

National Bureau of Standards, June, 1978), 514 pages,

2. FitzSimons, N. , "Research Support for Building Rehabilitation Studies

in the Area of Strength and Stability Evaluation," unpublished,

(July 1, 1979).

3. Definition by Clifton, Dr. J.R. , "Research Chemist, National Bureau of

Standards, Center for Building Technology, Washington, D.C.

4. Fisher, D. A., "The Epic of Steel," Harper and Rowe Publishers, N.Y.,

Evanston, and London, (1963), pp. 152-196.

5. Smith, C. S. , Editor, "The Sorby Centennial Symposium on the History of

Metallurgy," Sponsored by the Society for the History of Technology;

American Society for Metals; and the Metallurgical, Society, American

Institute of Mining, Metallurgical, and Petroleum Engineers; Cleveland,

Ohio, (October 22-23, 1963).

6. Aitchison, L. , "A History of Metals," Vols. 1 & 2, New York,

Interscience Publishers, (1960).

7. Unpublished report performed by the Solar Environmental Engineering

Co., Inc., Ft. Collins, Colorado, 1980.

8. Jacobs, P., "Technical Assessment of Existing Federal Buildings for

Solar Energy Retrofit," Solar Environmental Engineering Co., Inc.,

(May 1980).

9. "Inspection Checklist for Vintage Houses - A Guide for Buyers and

Owners," THE OLD-HOUSE JOURNAL, (1975).

10. "Basic Housing Inspection, Community Environmental Management Series,

U.S. Department of Health, Education, and Welfare, Public Health

Service, Bureau of Community Environmental Management, 1970.

11. Baechler, R. H. , Gjovik, L. R. , "Selection, Production, Procurement,

and Use of Preservative-Treated Wood," Forest Products Lab., USDA,

Specification TT-W-571.

12. Anderson, L. 0., "Selection and Use of Wood Products for Home and Farm

Building," Forest Products Lab., USDA, Vol. 311, (February, 1967).

13. Scheffer, T. C. , Verrall, A. F., "Principles of Protecting Wood

Buildings from Decay," Forest Products Lab., USDA, FPL 190, (1973).

14. DeGroot, R. C. , "Your Wood can Last for Centuries," Forest Products

Lab., USDA, (1976).

71
15. "Wood Handbook: Wood as an Engineering Material," Forest Products

Lab., USDA, Handbook No. 72, (1974).

16. Black, Fiest, Gjovik, Rowell, "Protecting Log Cabins from Decay,"

Forest Products Lab., USDA, (1977).

17. Anderson, L. 0., Sherwood, G. E. , "Condensation Problems in your

House: Prevention and Solution," Forest Service, USDA, Agriculture

Bulletin No. 373, (September 1974).

18. Sherwood, G. E. , "New Life for Old Dwellings," Forest Products Lab.,

USDA, Vol. #481, (December 1975).

19. "PILODYN Wood Tester, Operating Instructions," ProceQ SA Zurich,

Switzerland.

20. Scheffer, T. C. , "A Climate Index for Estimating Potential Decay in

Wood Structures Above Ground," Forest Products Lab, USDA, Vol. J21(10).

21. Dampness in Basements and Ground Floors , LC 813 (Washington, D.C.:

National Bureau of Standards, August 17, 1953), 17 pages.

22. McMaster, R. , Editor, "Nondestructive Testing Handbook," Ronald Press,

New York, (1959).

23. Haverty, M. I., "You Can Protect Your Home from Termites," USDA.

24. Smythe; Williams; "Structural Pest Control Regulations," USDA, (1974).

25. "Subterranean Termite Control Proposal", Orkin Exterminating Co.,

Inc., (February 1973).

26. Haverty, M. I., "Have Termites? Don't Panic!" U.S. Forest Service,

USDA.

27. Johnson, S. , "Deterioration, Maintenance, and Repair of Structures,"

McGraw-Hill, Inc. (1965).

28. "PILODYN, "A Non-destructive Wood Tester," Manufacturer's Literature,

Carl Bechgaard, Hovegaden 26, DK 2970 Horsholm, Denmark.

29. Proceedings of the Fourth Nondestructive Testing of Wood Symposium,

Held at Vancouver, Washington, August 28-30, 1978, published by the

Engineering Extension Service, Washington State University.

30. Berger, H., Mordfin, L. , Editors, Annual Report 1978, Office of

Nondestructive Evaluation , NBSIR 78-1581, (Washington, D.C., National

Bureau of Standards, January 1979), 51 pages.

72
31. Eldridge, H. , "Common Defects in Buildings,” Department of the

Environment, Property Services Agency, Her Majesty's Stationery Office,

London, (1976).

32. "Practices for Evaluation of Concrete in Existing Massive Structures

for Service Condition," No. ACI 207R-79, CONCRETE INTERNATIONAL,

(March 1979).

33. Sevall, G. , "Nondestructive Testing of Construction Materials and

Operations," AD-774 847, U.S. Department of Defense, Army Cnstruction

Engineering Research Laboratory, (December 1973).

34. Snell, L., "Nondestructive Testing Techniques to Evaluate Existing

Masonry Construction," (August 1978).

35. "Standard Specification for Ceramic Glazed Structural Clay Facing Tile,

Facing Brick, and Solid Masonry Units," C-126, American Society for

Testing and Materials, (1976).

36. "Nondestructive Testing," Reference Manual for a Home Study and

Extension Course, by the American Society for Metals, the American

Society for Nondestructive Testing, and the Metals Engineering Institute,

Metals Park, Ohio, (1972).

37. Vary, A., "Nondestructive Evaluation Technique Guide," National

Aeronautics and Space Administration, Washington, D.C., (1973).

38. "Home Repair and Improvement - The Old House," by the Editors of

Time-Life Books, (1979).

39. Dubin, F., Long, G. G., Jr., "Energy Conservation Standards for Building

Design, Construction, and Operation," McGraw Hill Book Co., (1978).

40. ASHRAE Handbook and Product Directory, 1977 Fundamentals.

41. ASHRAE Handbook and Product Directory, 1979 Equipment.

42. Crenshaw, R. , Clark, R. , Chapman, R. , Grot, R. , and Godette, M. , CSA

Weatherization Demonstration Project Plan , NBSIR 79-1706 (Washington,

D.C.: National Bureau of Standards, March 1979).

43. Tamura, G. T. , "Measurement of Air Leakage Characteristics of Home

Enclosures," ASHRAE Transactions, V81, Part 1, American Society of

Heating, Refrigerating, and Air Conditioning Engineers, New York,

N.Y., (1975).

44. Strieker, S. , "Measurements of Air-tightness of Houses," ASHRAE

Transactions, V81, Part 1, American Society of Heating, Refrigerating,

and Air Conditioning Engineers, New York, N.Y. (1975).

73
45. Kronvall, J. , "Testing of Houses for Air Leakage Using a Pressure

Method," ASHRAE Transactions, V81, Part 1, American Society of Heating,

Refrigerating, and Air Conditioning Engineers, New York, N.Y., (1975).

46. Grot, R. A., "A Method for Collecting Air Infiltration Rates in a Large

Scale Dwelling," Proceedings of ASTM Conference on Air Infiltration,

American Society for Testing and Materials, Philadelphia, PA, (March

1978).

47. Grot, R. A., Harrje, D. S. , and Johnston, L. C. , "Application of

Thermography for Evaluating Effectiveness of Retrofit Measures,"

Proceedings of the 3rd Biennial Infrared Information Exchange, AGA

Corp. , Lecancus, N. J. , (1976).

48. Hurley, E. W. , and Kreider, K. G., Application of Thermography for

Energy Conservation in Industry , NBS Technical Note 923 (Washington,

D.C.: National Bureau of Standards, October 1976).

49. Pettersen, B. , and Paljak, J. , "Thermography of Buildings, "The National

Swedish Institute for Building Research, AGA Corp. , Stockholm, Sweden.

50. "Basic Plumbing Code," (BPC) 1978. Building Official and Code

Administrators International, Inc., 17926 South Halsted, Homewood,

Illinois, 60430.

51. "National Standard Plumbing Code," (NSPC) 1978. National Association

of Plumbing-Heating-Cooling Contractors (NAPHCC) and American Society

of Plumbing Engineers (ASPE), 1015 20th Street, N.W. , Washington, D.C.

20036.

52. "Standard Plumbing Code (SPC) 1979," Southern Building Code Congress

International, Inc. (SBCC), 900 Montclair Road, Birmingham, Alabama

35213.

53. "Uniform Plumbing Code (UPC) 1976," International Association of

Plumbing and Mechanical Officials (IAPMO), 5032 Alhambra Avenue,

Los Angeles, California, 90032.

54. Manas, V. T. , "National Plumbing Code Handbook - Standards and Design

Information," McGraw Hill Book Company, Inc.

55. "Uniform Building Code - Interpretation and Inspector’s Manual," 1st

Edition, International Association of Plumbing and Mechanical Officials,

(1971).

56. Blinn, B. C. "Properties and Uses of Color Change Humidity Indicators,"

Humidial Company, Colton, CA.

57. ASHRAE Handbook of Fundamentals, Chapter 13, (1977).

74
58 . Sonderegger, R. C. , Modera, M. P., "Electric Co-heating: A Method for

Evaluating Seasonal Heating Efficiencies and Heat Loss Rates in Dwellings," Lawrence Berkeley Laboratory, University of California, Berkeley,

California. (Draft Report - Presented at the 2nd CIB Conference,

Copenhagen, Denmark, June 1979).

59. Fowler, K. A., Elfbaum, G. M. , Husarek, V. , Castel, J. , "Applications

of Precision Ultrasonic Thickness Gauging, "Panametrics, Waltham, MA.

60. Sunley, J. G. , "Review of Nondestructive Testing of Timber," Symposium

on Nondestructive Testing of Concrete and Timber, London, (1969).

61. "Basic Building Code 1978,” Section P-1802.5 la, Building Officials and

Code Administrators, International, Inc., 17926 South Halsted, Homewood,

Illinois, 60430.

62. "Tentative Guide Specification, Plumbing,” GSA, Public Buildings

Service, Section 15410 T, pp. 30-32, (Nov. 1978).

63. "Standard Plumbing Code 1979," Section 107.5a, Southern Building Code

Congress, International, Inc., 900 Montclair Road, Birmingham, AL,

35213.

64. "Standard Plumbing Code 1979," Section 1602. lOe, Southern Building Code

Congress, International, Inc., 900 Montclair Road, Birmingham, AL,

35213.

65. Performance Criteria Resource Document for Innovative Construction , NBSIR 77-1316, (Washington, D.C.: National Bureau of Standards,

November 1977), p. 123, 13.6.7.5, "Criterion: Hydraulic and Pneumatic

Performance - DWV Stack and Building Drain Assembly."

66. Orloski, M. J., Wyly, R. S. , Hydraulic Performance of a Full-Scale

Townhouse System with Reduced Sized Vents , Building Science Series

BSS 60, (Washington, D.C.: National Bureau of Standards, August 1975).

67. Konen, T. P. , "The Evaluation of Several Plumbing Drainage, Waste and

Vent Systems," Report DL-74-1776, Stevens Institute of Technology,

(1974).

68. Jackson, R. , Konen, T. P. , "An Investigation of the Adequacy of

Performance of Reduced-Sized Vents Installed in a Ten Story Drain,

Waste and Vent System," Stevens Institute of Technology Report SIT

DL-1708, (July 1973).

69. Konen, T. , "A Test Procedure for Evaluating the Capacity of the Building

Drainage Systems," Report DL-75-1841, Stevens Institute of Technology,

(1975).

75
70. Wyly, R. S. , Rorrer, D. E. , Field Test of Hydraulic Performance of a Single-Stack Drainage System at the Operation BREAKTHROUGH Prototype

Site in King County, Washington , NBSIR 73-161 (Washington, D.C.

:

National Bureau of Standards, May 1973.

71. Maybeck, E. , "Demonstration of Performance for a Sovent System

Installed at Townsend Towers Near East Side Urban Renewal Project,

Syracuse, N.Y.," Barnard and Maybeck, Rochester, N.Y., (1972).

72. Performance Criteria Resource Document for Innovative Construction , NBSIR 77-1316 (Washington, D.C.: National Bureau of Standards,

November 1977), page 122.

73. "Inspection Guide, Electrical Systems," GSA, Public Buildings Service,

PBS P 3480.2, Section 1605.

74. "National Electrical Code 1978," Paragraph 210-19, Conductors - Minimum

Capacity and Size, National Fire Protection Association, 470 Atlantic

Avenue, Boston, Massachusetts, 02210.

75. AMP, Incorporated, Harrisburg, Pennsylvania.

76. Multi-Amp Corporation, Dallas, Texas, 75237.

77. James, W., "Electric Moisture Meters for Wood," U.S. Forest Service,

General Tech. Report FPL-6, (1975).

78. Duff, J. L. , "A Probe for Accurate Determination of Moisture Content

of Wood Products in Use," U.S. Forest Service Research Note FPL-0142,

(1966).

79. Pellerin, R. F. , "Nondestructive Testing of Timber at Washington State

University," Symposium of Nondestructive Testing of Concrete and Timber,

London, (1969).

80. Elvery, R. H. , "Strength Assessment of Timber for Glued Laminated Beams",

Symposium on Nondestructive Testing of Concrete and Timber, London,

(1969).

81. "Bugs:Blights:Blazes . . . Enemies of the Southern Forest," U.S.

Forest Service, USDA, (1978).

82. Beal, Johnson, Smith, "Subterranean Termites, Their Prevention and

Control," USDA Bulletin, Vol. 64, (January 1972).

83. Schaeffer, E. L. , "Review of Information Related to the Charring Rate

of Wood", U.S. Forest Service, USDA, (November 1966).

76
84. "Fundamentals of Nondestructive Testing," by the American Society for

Metals and the American Society for Nondestructive Testing, Reference

Manual for an Extension Course of the Metals Engineering Institute,

Metals Park, Ohio, (1979).

85. DiGiacomo, G. , Crisci, J. , Goldspiel, S., "An Ultrasonic Method for

Measuring Crack Depth in Structural Weldments," MATERIALS EVALUATION,

Vol. XXVII, No. 9, (September 1970).

86. Nondestructive Evaluation Equipment Literature from the Olympus Corp

of American, New Hyde Park, N.Y.

87. Nondestructive Evaluation Equipment Literature from the KrautkramerBranson Co., Stratford, CN.

88. "Nondestructive Testing: Trends and Techniques," Proceedings of the

Second Technology Status and Trends Symposium, Marshall Space Flight

Center, NASA, Publication No. SP-5082.

89. "Annual Book of ASTM Standards, Part II, Metallography: Nondestructive

Testing," by the American Society for Testing and Materials, (1977).

90. "Review of Preconstruction Data, Construction, Operation and Maintenance

Records," CONCRETE INTERNATIONAL, (March 1979), pp. 48-50.

91. Dick, P., "Introduction to Nondestructive Testing," General Electric

Company, Written for the Metals Engineering Institute, (1979), page 1.4.

92. "Solar Federal Building Program Plan," Unpublished Report by U.S.

Dept, of Energy, (February 1, 1980).

93. "Building Code Requirements for Reinforced Concrete," ACI 318, American

Concrete Institute, (1977).

94. "Standard Specification for Blended Hydraulic Cements,” C 595, American

Society for Testing and Materials, (1976).

95. Kemp, E. , "An Introduction to the Structural Evaluation of Historic

Reinforced Concrete Structures," CONCRETE INTERNATIONAL, (October 1979).

96. Hansome, E. , Saurbrey, A., "A Selection of Historic American Papers on Concrete, 1876 - 1926," American Concrete Institute.

97. Lesley, R. , "History of the Portland Cement Industry in the United

States, (1924), page 33.

98. Turner, C. , "Concrete Steel Construction," (1909), pages 245-284.

99. Urquhart, L. , "Civil Engineering Handbook," (1962).

77
100. Draffin, J. , "A Brief History of Lime, Cement, Concrete, and Reinforced

Concrete," JOURNAL OF THE WESTERN SOCIETY OF ENGINEERS, Vo. 48, No. 1,

(March 1943), pages 14-47.

101. Maples, W., Wilde, R. , "A Story of Progress - Fifty Years of the American

Concrete Institute,” Title No. 50-25, JOURNAL OF THE AMERICAN CONCRETE

INSTITUTE, Vol. 25, No. 6, Proceedings Vol. 50, (February 1954).

102. Kerekes, F. , and Reid, H. , "Fifty Years of Development in Building Code

Requirements for Reinforced Concrete," Title No. 50-26, JOURNAL OF THE

AMERICAN CONCRETE INSTITUTE, Vol. 25, No. 6, Proceedings Vol. 50,

(February 1954).

103. Perkins, P. , "Concrete Structures: Repair, Waterproofing and

Protection," (1977).

104. "Concrete Manual," A Water Resource Technical Publication, U.S.

Department of the Interior, Bureau of Reclamation, (1975).

105. Hough, B. , "Basic Soils Engineering," (1957).

106. Malhotra, V., "Testing Hardened Concrete: Nondestructive Methods,"

American Concrete Institute Monograph No. 9, (1976).

107. Vassitch, P. , "Outline of the Various Possibilities of Nondestructive

Mechanical Tests on Concretes: New Proposals of the Author," Proceedings of the International Symposium on Nondestructive Testing of

Materials and Structures, Vol. 2, RILEM, Paris, (1954), pages 301-306.

108. Leslie, J. , Cheeseman, W. , "An Ultrasonic Method of Studying

Deterioration and Cracking in Concrete Structures," ACI JOURNAL,

(September 1949).

109. "Strength Evaluation of Existing Concrete Buildings," ACI 437, American

Concrete Institute, (1975).

110. "Standard Method of Obtaining and Testing Drilled Cores and Sawed Beams

of Concrete," C-42, American Society for Testing and Materials, (1977).

111. NDE (Nondestructive Evaluation) , LC 1080 (Washington, D.C. : National

Bureau of Standards, April 1978).

112. Promotional Information, Olympus Corporation of American, New Hyde

Park, New York.

113. "Standard Method of Sampling and Testing Bricks and Structural Clay

Tile," C-67, American Society for Testing and Materials, (1978).

114. Fattal, S. , Cattaneo, L. , Evaluation of Structural Properties of Masonry

in Existing Buildings , NBS BSS 62 (Washington, D.C.: National Bureau

of Standards, March 1977), 127 pages.

78
115. "Durability," British Standard Code of Practice CP3 - Chapter IX,

by the Council for Codes of Practice for Buildings, (1950).

116. "Nondestructive Inspection and Quality Control," Metals Handbook, 8th

Edition, Vol. I & II, American Society for Metals, Metals Park, Ohio,

(1976).

117. Krautkramer, J. , Krautkramer, H. , "Ultrasonic Testing of Materials,"

Springer - Verlag, New York, 2nd Edition, (1969).

118. Halmshaw, R. , Editor, "Physics of Industrial Radiology," Heywood Books,

London, (1966).

119. "Radiography in Modern Industry," Eastman Kodak Co., Rochester, New

York, 3rd Edition, (1970).

120. McGonnagle, W. , "Nondestructive Testing," Pergamon Press, New York.

121. Sharp, R. , Editor, "Research Techniques in Nondestructive Testing,"

Academic Press, London, (1980).

122. McKay, J., "Effect of Moisture Gradients on the Accuracy of Power

Loss Meters," Forest Products Lab., USDA, FPJ 26(3), pages 49-52.

123. "Standard Test Methods for Moisture Content of Wood," D 2016,

American Society for Testing and Materials, (1974).

124. "Standard Methods for Establishing Structural Grades and Related

Allowable Properties for Visually Graded Lumber," D 245, American

Society for Testing and Materials, (1974).

125. "Standard Method for Establishing Clear Wood Strength Values," D 2555,

American Society for Testing and Materials, (1976).

126. McDonald, K. , "Ultrasonic Location of Defects in Softwood Lumber,"

USDA, Technical Article in the TIMBER TRADES JOURNAL, (January 1973).

127. McDonald, K. , "Lumber Defect Detection by Ultrasonics," Forest Products

Lab., USDA, Research Paper FPL 311, (1978).

128. Gerhards, C., "Stress Wave Speed and MOE of Sweetgum Ranging from 150

to 15 percent MC," Forest Products Lab., USDA, FPL Journal, Vol. 25,

No. 4, (1975).

129. Fala, M. J. "Principles of Residential Plumbing Inspection," 1st

Edition, American Society of Sanitary Engineering, (1973).

130. "Draft Rehabilitation Guidelines," Department of Housing and Urban

Development, Federal Register Volume 44 - No. 215, Book 2,

November 5, 1979.

79
131. McMaster, R. C. , Ed., "Nondestructive Testing Handbook," Ronald Press,

New York, (1959).

132. Krautkramer , J., Krautkramer, H. , "Ultrasonic Testing of Materials,"

Spring-Verlag, New York, 2nd Ed., (1969).

133. Halmshaw, R. , Ed., "Physics of Industrial Radiology," Heywood Books,

London, (1966).

134. "Radiography in Modern Industry," Eastern Kodak Co., Rochester, New

York, 3rd Ed., (1970).

135. McGonnagle, W. J., "Nondestructive Testing, Pergamon Press, New York.

136. Sharp, R. S., Ed., "Research Techniques in Nondestructive Testing,"

Academic Press, London, (1970), (1973), (1976), (1980).

137. Vary, A., "Nondestructive Evaluation Technique Guide," National

Aeronautics and Space Administration, Washington, D.C., (1973).

138. "Standard Methods of Tension Testing of Metallic Materials," ASTM E 8,

American Society for Testing and Materials, (1977).

139. "Standard Methods of Compression Testing of Metallic Materials at Room

Temperature," ASTM E 9, American Society for Testing and Materials,

(1977).

140. Kaiserlik, J. , "Nondestructive Testing Methods to Predict Effect of

Degradation on Wood: A Critical Assessment," Forest Products Lab,

USDA, General Tech. Report FPL 19, (1978).

80
APPENDIX A

Typical Forms for

Collection of Data During Preliminary On-Site Investigation

A-l
APPENDIX A

PROJECT DOSSIER [2]

The accumulation of data during the on-site investigation should be done in an organized manner. At this point it may be helpful to establish a Project

Dossier. The Dossier is made up of a project notebook and a file which contains all correspondence pertaining to the project as well as collected

reference material.

The forms which should be kept with the Dossier are as follows:

A. Project Notebook

1. General Building Information Form (see sample attached)

2. Member /Assembly Information Form

3. Journal Entry List

4. Contact List

5. Document List

6. Photo List

7. Sketch List

8. Specimen List

B. Project Files

1. General Correspondence

2. Journal Entry Supplements

3. Collected Documents and Citations

4. Photographs and Negatives

5. Field Reports and Sketches

6. Test Results

7. Analytical Studies

8. Evaluation Report

A2
Form A-l

GENERAL BUILDING INFORMATION

Project #: Date: Investigator:

1) Building Name:

2) Street Address:

3) Place

:

4) Country: 5) State : 6) Zip:

7) Building Authority:

8) Architect /Engineer

:

9) Builder:

10) Documentation:

ID Construction Dates:

12) Vacancy Date:

13) Site Description:

14) Area: Ground Plan: Gross: Net:

15) Stories

:

16) Structure:

17) Roof

:

18) Exterior Walls:

19) Interior Walls: 20) Fenestration:

21) Floors

:

22) Girders

:

23) Columns

:

24) Basement

:

25) Footings

:

26) Supplemental Information:
Form A-2

COMPONENT/ASSEMBLY INFORMATION

Project #

: Date: Investigator:

1) Building Name:

2) Street Address:

3) Place

:

4) Country

:

5) State: 6) Zip:

7) General Description:

8) Condition:

9) Deficiencies

:

10) Causes of Deficiencies:

11) Loads

:

12) Agents

:

13) Materials Qualities:

14) Member/Assembly Properties:

15) Remarks

:

Include detailed sketches of the member/assembly on the reverse side of the

form. Include its location in the overall system. Scales must be shown for

each sketch. Original outlines may be shown as dashed lines over the as-is

state.

A4
Form A-3

JOURNAL ENTRY LIST

JOURNAL ENTRY LIST #

Client:

Project:

Project Name:

Entry By: Entry Date:

Location:

Remarks

:

Form A-4

CONTACT LIST

CONTACT LIST #

Client:

Project:

Project Name:

Name: Title:

Association:

Telephone: ( ) ( ) ( )

Dates

:
Form A-5

DOCUMENT LIST

DOCUMENT LIST £

Client:

Project:

Project Name: Number:

Description:

Repository: Date Mark:

Author/Authority:

Remarks

:

Form A-6

PHOTOGRAPH LIST

PHOTO LIST £

Client:

Project:

Title:

Description:

Reference #: Reference Sketch:

Camera: Location: Orientation:

Site Conditions: Date: Time:

Photographers: Repository:

Remarks

:
Form A-7

SKETCH LIST

SKETCH LIST #

Client:

Project:

Project Name: Number:

Subject:

Objective:

Scale: Photo Ref. #:

Date: Time: Sketcher:

Remarks

:

Form A-8

SPECIMEN LIST

SPECIMENT LIST #

Client:

Project:

Project Name: Number:

Specimen:

Description:

Cond. @ Removal: Means of Removal:

Loc. @ Removal: Sketch Ref. #:

Photo. Ref. //: Sketch Ref. #:

Remarks

:

A-7

APPENDIX B

Recommended Equipment for Field Inspection

B-l
APPENDIX B

Recommended Equipment for Field Inspection [2, 7]

Camera, 110 (pocket type) with flash and film

Camera, 35mm (f3.5/50mm, or larger aperture) with flash & film

Lens, telephoto

Lens, wide angle

Tripod, camera

Recorder, Cassette (Pocket Type)

Binoculars, 7 x 35mm or better

Monocular, 8 x 20mm

Magnifier, pocket style, 4x to lOx

Mirror, inspection

Optical distance-measurer

Fiberscope, flexible

Reticle, millimeter tenths scale

Level, hand

Level, circular

Level, vial

Level, carpenter's 4 ft.

Caliper, inside/outside 5 in.

Rule, 5 in. with millimeter scale

Rule, folding 6 ft.

Tape, 50 ft.

Scale, Engineer's

Scale, Architect's

Gauge, feeler

Flashlight

Penlight

Flexilight

Calculator, pocket

Hammer, masonry

Hammer, ball peen

Awl or ice pick (to check for rot in wood)

Plumb bob

Screwdriver

Pen knife

Handbook, Engineering (pocket-type)

Project Notebook with blank forms

Clipboard with blank, ruled and graph paper

Pocket Notebook (3-3/4" x 6-3/4")

Bags, Specimen

Tape and gummed labels

Felt markers and crayons

Heavy string and thumb tacks (to check sag or bulge)

Tape, plastic

Tape, "scotch"

Cards, Marking (5" x 8")

Hairspray, Aerosol

B-2
Penetrant dyes

Glass cover slips

Glue, cyanoacrylate or comparable

Hat, safety - shoes, safety - gloves, canvas Electrical analyzer (plug-in type)

Magnet

Matches (to check draft)

Pencil and paper

Insertion thermometer

Manometer

Pitot tube

Tachometer

Clamp on ammeter with voltage scales

Differential pressure gage

B-3
i; ! i !

’• ' . fi ~: ; t ..

,-i " - v ' -
APPENDIX C

Potential Sources of Information on Buildings Being Considered for Solar Retrofit

C-l
APPENDIX C

Potential Sources of Information on Buildings Being Considered for Solar Retrofit [2]

A. At the building site (facility engineer's files):

° Original drawings and specifications, including elevations, structural,

mechanical/electrical, plumbing, HVAC)

° Operation and maintenance records

° Remodeling and maintenance records

0 As-built drawings

° Fire inspection details

0 Photographs

° Contracting officer's files, including laboratory records, certificates

of compliance with specifications, batch plant reports, inspection

reports, etc.

B. Building Contractor Files:

° Original drawings

° Preconstruction data

° Construction progress reports

° As-built drawings

° Final completion report

0 Progress photographs and final photographs

° Landscaping and exterior details

0 Operation and maintenance records

C. Surveying Contractor Files:

0 Property line survey records

° Lot location information

° Elevations

C-2
° Topographical map of site and drainage area

° Geological maps, profiles, and cross sections

° Water table elevations

° Geohydrological data

° Seismic data

D. Local Weather Bureau:

° Temperatures: maximum, minimum, and mean daily

° Precipitation: maximum, mean annual, snow accumulation

° Average humidity and range

° Solar index

° Air quality index: maximum and mean daily

0 Other climatological data

E. Local and Major Federal or State Newspapers:

° Photographs (usually only final)

° Articles on design features

° Renovation or alteration articles

° Construction progress articles

F. Local and State Historical Societies and Local Library Historical Sections:

° Interior and exterior photographs

° Building records

° Historical information (past owners, past uses, important events at

the building site, etc.)

° Especially check the Historic American Building Survey or the Historic

American Engineering Record (U.S. Department of the Interior, Heritage

Conservation and Recreation Service, Pension Building, Washington, D.C.)

C-3
'

.
APPENDIX D

Methods for the Detailed Evaluation of Systems

APPENDIX D.l

Concrete Systems

D-l
TABLE

14.

CONCRETE

EVALUATION

TECHNIQUES

D-2
TABLE

14.

CONCRETE

EVALUATION

TECHNIQUES

-

(CONTINUE!!)

D-3
TABLE

14.

CONCRETE

EVALUATION

TECHNIQUES -

(CONTINUED)

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ff

M 2

B. 4 • IS 35 £ 5 X • a $ 4 4 <2

B 44 0 44 4 4 4 4 4 K | W « M X 4 0 £ 0 :S 8 ?

s.JS 2 .4 3 18 8 J82 3 0*1

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SI* . 4 b 4 0

ft*

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ft. 3 ft. u a a x ft. e

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APPENDIX D.2

Wood Systems

D-5
TABLE

15.

WOOD

EVALUATION

TECHNIQUES

D-6
TABLE

15.

WOOD

EVALUATION

TECHNIQUES -

(CONTINUED)

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(0 Li cr 4-i r-i CO 4-1 CO c ai a> 3 C O o CL <y oh <u • a> cl

•H 4-1 r-H

B ^ 4-1B CL •

4-1 3 CO J3

C CO

a o c

eg 0) d) eg eg 4-1O o d) •u d 4-1 Ll X CO u *H O B

•H •H d) 3 4) 4J -H s eg x 3 co B iH > a

•H Li eg *h •H eg ey co qi

-»-• rH CO 3 •H 3 CO CL d c c 4-1 <y co

CO • CO

OO eg •H

b o

d) <y <y o •H

d *HU AJ

Li 4-1 Li AJ 0) •H •H eg CO •h eg •H CO eg 3 *4-4 01 3 Li 3 <y *H CO 0) AJ a* a) a* 3 CO oc Li >

0) CL

od o <2 e2 3U

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<4-1 -C o • o 3 *H

Li AJ O eg • OH CJ 3 d> •

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4-1 :*

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iH co c eg *D eg eg Li

B *3 AJ 3 o •—1 d o

X) c d) •H s CO 4-1 TJ T3 d) <D

C CO Li •H <3•H

eg o Ll <y 3 CO (U o ax <y • eg <U -C

d AJ Cl •H 4-1 AJ X eg rH CO o 60 AJ 0) > AJ •H eg

eg 4-1 CO -Q eg P a> eg :* rH •H

C 60

B o •H

CJ egX

C -H • .£) eg 0)OC x: AJ • Li 60 a> 3 4-1 •H OH Li £ O •H OH CO CJ d eg

eg CO 0) • aj a) o 3 o e d a) CO > a Li CJ 3 J3 >* O *H Ll AJ >% a) Li o iH CJ rH o a) c o AJ aj aj a eg CO u rH Ll •3 a) rH Li eg

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<u eg OH <y Li rH

u eg o a CD AJ *H 4J CL Li

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D-7
APPENDIX D.3

Masonry Systems

D-8
D-9
TABLE

16.

MASONRY

EVALUATION

TECHNIQUES

-

(CONTINUED)

D-10
TABLE

16.

MASONRY

EVALUATION

TECHNIQUES

-

(CONTINUED)

D-ll
TABLE

16.

MASONRY

EVALUATION

TECHNIQUES

-

(CONTINUED)

D-12
APPENDIX D.

4

Metal Systems

D-13
TABLE

17.

METAL

EVALUATION

TECHN

IgUES

D-14
TABLE

17.

METAL

EVALUATION

TECHNIQUES

-

(CONTINUED)

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D-15
APPENDIX D.5

HVAC Systems

D-16
D.5 HVAC SYSTEMS

D. 5. 1 GENERAL

This section covers methods which supplement the information derived from

the preliminary evaluation discussed in section 4. Methods outlined in this

section include those procedures which are more detailed or sophisticated

than those given under section 4. Accordingly, they will require a greater

degree of expertise, understanding, judgment, and time. They should be con- ducted after the preliminary procedures of section 4, have been completed

and the HVAC systems are still considered to be sound candidates for solar

retrofit

.

D. 5. 2 GUIDELINES

D.5. 2.1 Determining Infiltration Rate Using Tracer Gas [42, 46]

The actual infiltration air exchange rate within a structure can be determined

through the use of a tracer gas which is released into the space to be measured.

The concentration of the gas then is monitored over a period of time, and the

exchange rate can be expressed through the following relationship:

I = - Vt In ( c /co)

where: I = infiltration rate as air volume changes per hour

t = time

co = concentration of tracer gas at time zero (beginning of test)

c = concentration of tracer gas at a specific time within the test

period

.

When the natural logarithm (In) of the relative concentration ( c /co) is

plotted as a function of time, the rate of infiltration (I) is the negative

slope of the best fit line through the data points. Several tracer gases,

such as carbon dioxide, helium, nitrous oxide, ethane, methane, and others,

have been used as indicators of concentration of decay due to infiltration.

Currently one of the most popular is sulfur-hexafluoride (SF 5

). Samples

of the air within the structure are taken and analyzed on the spot or stored

in sample bags during the test and later analyzed.

The tracer gas technique is probably the best measure of natural infiltration

because it does not introduce any unnatural constraints for making the determinations (other than some form of forced air circulation within the space to

maintain mixing of tracer gas and air). The use of sulfur-hexafluoride requires

very small amounts of harmless gas (generally on the order of 10-50 parts per

billion) thus altering to a negligible extent the composition of the air.

At infiltration rates of greater than three air changes per hour, the tracer

gas technique may give unreliable results because of the introduction of larger

D-l 7
amounts of unmixed air causing significant scatter in the data. Although higher

rates of exchange seldom are encountered, where they do occur, greater care

in mixing and more frequent sampling may be required.

D. 5.2.2 Determining Humidity with Color Changing Agents [56]

The color change humidity indicator is a simple, inexpensive device for

monitoring relative humidity within a structure. One such indicator uses cobaltous chloride as the basic ingredient for indicating the relative

humidity. Cobaltous chloride is exposed to the atmosphere on blotting paper,

and when equilibrium is reached, the color of the ingredient changes. Plugtype indicators may be used to indicate the relative humidity in wall cavities and in enclosed roof ceiling cavities. Color change indicators may be

used also to monitor the relative humidity in occupied spaces.

The available relative humidity range for various chemicals is from 10 to 80

percent. It is possible to measure relative humidity within five percent of

the published equilibrium point. A 10°F change in temperature will affect

indicator accuracy by only 2-1/2 percent. Because the equilibrium point

varies with the specific chemical used, a particular chemical is accurate only

at a specific humidity (not a range). The accuracy of the indicator may be

affected by temperature changes and long-term exposure to high humidity,

high temperature, or direct sunlight. Direct contact with water also will

cause the chemicals to leach out of the paper and thus lose their calibration.

D.5.1.3 Determining Humidity with an Electric Hygrometer [57]

With a change in humidity, many substances absorb or give up moisture and

exhibit changes in electrical impedance. Sensors are available which have

dual electrodes or windings that are electrically separated by a thin film of

binder material containing a salt solution (such as lithium chloride). Means

are provided for measuring the AC electrical impedance between the electrodes

through the salt film. Since the impedance through the salt responds to

changes in relative humidity and temperature, accurate indications of relative

humidity can be obtained.

These electrical impedance hygrometers are relatively sensitive to humidity

changes and are adaptable for remote read-out. Accuracy is in the order of

+1.5 percent RH and elements are available to cover the range from 10 to 90

percent RH. Because the electrical impedance hygrometer is susceptible to

damage by air contaminants and water, frequent calibration checks are required.

Nevertheless, elements may be placed in remote places for monitoring changes

in relative humidity under high humidity conditions.

D.5.1.4 Determining Heating System Efficiency by Using Electric

Co-Heating [58]

Electric co-heating is a technique used to determine the net efficiency of a heating system (a furnace, for example) within a house. Several portable,

thermostatically controlled, and metered electric heaters are distributed

throughout the house. The furnace is turned off, and only the electric

D-18
heaters are used to measure the total heat consumed in the house. Next, the

furnace is turned on and cycled manually at an arbitrary rate (for example,

four minutes on and sixteen minutes off) for about three hours. Throughout

the procedure, the indoor temperature is kept constant by appropriate control

of the heat provided by the electric heaters. Finally, the furnace is turned

off and the electric heaters again carry the full load to obtain a check on

the total load.

The indoor temperature is recorded and periodic measurements of the outdoor

temperature are taken. Also, the air infiltration rate (through cracks in

walls, etc.) is monitored using tracer gas techniques. The following steps are then used to calculate the net system efficiency:

1) The heat load, including air infiltration, is determined through

the power consumed by the electrical heaters operating alone.

2) The portion of the heat load supplied by the furnace is determined

from the difference between the measured total load and the measured

electrical power consumed by the heaters while operating in

conjunction with the furnace.

3) The efficiency is calculated by dividing this difference by the

average energy consumed by the furnace.

The electric co-heating technique also may be used to evaluate fireplace

efficiency, and to determine the fraction of the heating load needed for the

individual rooms in the dwelling. Unlike some methods of efficiency evaluation, electric co-heating cancels out distribution heat losses (through ducts,

etc.). In other words, the efficiency calculation includes only the heat

that benefits the living space. As a result, this method distinguishes

between heating system efficiency and the house's envelope performance.

Electric co-heating, however, is still in the development stage. For example,

it is not practical for use with structures having a large number of rooms because of the present difficulty in monitoring the infiltration losses and

the power consumed by the individual rooms.

D.5.2.5 Determining Wall Thickness of Containment Vessels [59]

It is possible to use ultrasonic techniques to determine the thickness of

materials to obtain an indication of wear and deterioration. The pulse-echo

ultrasonic thickness technique is recognized as an accurate method of measuring thickness of materials when the velocity of the pulse wave is known.

Ultrasonic transducers have been developed that will allow the determination

of piping and tubing wall thicknesses (as well as other forms) without

physically penetrating the material. Ultrasonic pulses are generated and the

time required for the pulse to be reflected back from the opposite surface is

very accurately recorded. By knowing the transmission velocity of the material, and with the appropriate electronic circuitry, a digital readout can be

obtained which is a direct measure of the thickness of the material. The

technique has been used to evaluate large boiler installations for heat

exchanger deterioration caused by corrosion.

D-l 9
Small transducers are available to determine thickness of closed materials

without physically penetrating the surface. By scanning the surface variations,

wall thickness can be determined, thus gaining an indication of deterioration.

Some distortion results from rough surfaces as the ultrasonic pulse is

scattered, with a resulting lack of sharpness in the return echo. As surface

curvature increases, the coupling efficiency between transducers and the

material to be measured decreases, causing some loss in accuracy. Some

materials have special acoustical characteristics and can cause scattering,

velocity variation, and attenuation, with a resulting loss of accuracy. For

these reasons, it is important that thickness determinations be made by

experienced personnel.

D.5.2.6 Determining Blower Revolutions per Minute (RPM) and Horsepower (HP)

to Maintain System Air Flow Rate [7]

When solar equipment is added to an existing warm air heating system, it may

become necessary to add a hot water heat exchanger to the existing ductwork.

This will increase system resistance and will require increased blower RPM to

maintain the original air flow rate. The RPM needed to overcome the increased

system resistance is determined by:

2!1 . 12. Ni Pj

where

Pj is the existing system static pressure

Nj is the existing blower RPM

?2 is the new system static pressure

N 2 is the new blower RPM required

The increased power requirements then are determined by:

HP

2 _f

N2l3

HPj |_N!j

where

HPj represents the existing power requirements as motor horsepower

HP2 represents the new power requirements resulting from the

increased RPM

The existing blower power can be determined by using an ammeter and a voltmeter

as described in section 6.1.3.

Blower manufacturers keep on file the blower performance characteristics of

all blowers manufactured by them. A set of characteristic curves for a simulated blower is illustrated in figure 7. With the existing system air

flow rate (CFM) and blower RPM known, the estimated existing system static

D-20
C/5 O

LU

OC

I o

\

9’M‘I 3UnSS3Hd 3I1V1S

FIGURE 7 [7]

D-21

SIMULATED

BLOWER

CHARACTERISTIC

CURVE
pressure drop may be estimated and the corresponding HP may be determined.

For example, according to figure 7, the simulated blower depicted is expected

to deliver 2400 CFM against approximately 1.4 inches of water system static

pressure, requiring approximately 1 HP of motor power, at a blower speed of

1000 RPM. Note: Figure 7 cannot be used for any other blower. The manufacturer's specific characteristic curves must be used for the specific blower

in question. Other methods for estimating the existing system CFM and system

static pressure drop are discussed in sections 4.2.9 and 4.2.10.

If a new heat exchanger coil is to be added to the existing blower system,

the coil manufacturer will supply data on the static pressure drop across the

coil for various standard air volumes. This additional resistance may be

added to the existing system static pressure to determine the new system

static pressure required to determine the new blower speed and HP discussed

above

.

For a belt driven blower, the blower speed may be increased by changing

the sheaves (pulleys) on the blower and/or the motor in accordance with the

following inverse relationship. The same relationship may be used to determine the existing blower RPM except that measuring RPM directly with a tachometer or a strobe light is much more accurate.

Blower RPM = Motor RPM x Dj/D2 where

is the motor pulley pitch diameter

D 2 is the blower pulley pitch diameter.

Direct drive fans may have a multi-speed motor. It then will be necessary to

check the motor nameplate to determine whether the motor is multi-speed, and

at which speeds it will operate. Also check the wiring of the motor against

a wiring diagram located on the nameplate or equipment to determine whether

the motor speed can be increased. If the blower speed cannot be increased,

an additional booster fan can be added in series with the existing fan to

restore system flow rate.

D. 2.5.7 Determining Duct Velocity [7]

The air flow requirements of a cooling system are approximately 400 standard

CFM (SCFM) per ton of cooling capacity. Since the air flow requirements for

a cooling system are greater than the air flow requirements for a heating

system, the retrofitting of an existing forced air heating system to include

cooling may pose some problems with duct size. Air duct velocities can be

determined from the system CFM and duct dimensions by a simple formula:

v = ACFM

A

D-22
where ACFM is the actual system air flow rate in ft-Vmin and A is the duct

cross-sectional area in ft . Table 18 shows recommended and maximum air

velocities for low pressure residential duct systems. If the duct velocity

exceeds the values listed in table 18, the ducts are undersized and should

be enlarged, or the system duct work redesigned to accommodate the increased

air volume required for cooling. Note - the table is for low pressure duct

work. Medium and high pressure duct work will tolerate greater velocities.

D.5. 2.8 Determining Performance of Heating Coils [7]

This section covers the performance of central heating coils, zone heating

coils (fan coil units, reheat units), natural convective heating equipment,

and radiant heating equipment.

The performance of an existing forced air heating coil is limited by the

following factors:

1) Supply water temperature

2) Water flow rate

3) Return air temperature

4) Air flow rate

5) Coil construction - materials, number of passes, etc.

6) Coil surface area.

Return air temperature is governed by space comfort conditions and is not

appreciably alterable. Increasing the water flow rate has limited effect on full coil capacity, as shown in figure 8. For a given heating coil construction and surface area, equivalent heat output can be obtained with decreasing

supply water temperature by increasing the air flow rate, as shown in figure 9.

Increasing air flow rate, however, introduces a number of potential problems.

This method is satisfactory only if:

1) The supply air temperature does not fall below a reasonable level

for room comfort;

2) The existing blower and/or the existing air supply terminal can be

modified economically to provide for the increased flow rate;

3) The potential increased noise is not objectionable;

4) The increased air velocity does not create objectionable drafts

within the space.

If these criteria cannot be met, it will be necessary to increase the heat

exchange area or consider installing a higher temperature solar heating

system (such as an evacuated tube or solar assisted heat pump system).

Additional heat transfer surface can be provided in a number of ways,

depending upon the equipment. It is easiest to either replace the coil in an existing unit or add an additional coil to the unit. This will depend

upon the replacement coils available for the unit, and whether or not space

is available for the inclusion of. an additional coil or a larger coil.

D-23
TABLE 18. RESIDENTIAL DUCT AIR VELOCITY [7]

Main Trunk Duct

Branch Ducts

Branch Riser

Outdoor Air Intake

Return Air Ducts

Air Collector Manifold Ducts . . .

Air Collector Riser Ducts . . . .

Recommended

Velocity FPM

(feet per minute)

Maximum

Velocity 1

700-900 1000

600 800

500 800

500 600

700 900

700-900 1000

800 1000

COMMERCIAL DUCT CLASSIFICATIONS

Low Pressure

Medium Pressure

High Pressure

Velocity Static Pressure

< 2000 fpm SP < 2 in W.G.

> 2000 fpm 2 in < SP < 6 in

> 2000 fpm 6 in < SP < 10 in

D-24
FIGURE 8 [7]

PERCENT OF DESIGN FLOW RATE

EFFECTS OF WATER FLOW RATE ON COIL HEAT TRANSFER FOR 20°F

WATER TEMPERATURE DROP AT 200°F WATER SUPPLY TEMPERATURE

FIGURE 9 [7]

PERCENT DECREASE IN SUPPLY WATER TEMPERATURE

INCREASE IN AIR FLOW REQUIRED TO MAINTAIN CONSTANT HEATING

COIL OUTPUT WITH DECREASE IN SUPPLY WATER TEMPERATURE

D-25
i

. *

i

• -

. • ; S

Another alternative is to add additional fan/ coil units. Each zone should

be analyzed, to determine whether additional units can be placed in the zone

.

j Table 19 shows the characteristic change in heating coil capacity with

changing supply water and return air temperatures, all other factors remaining constant. The table again illustrates how coil heat transfer capacity is

greatly reduced with decreasing supply water temperature.

This illustration is intended to show the limitations inherent with coil

performance characteristics. Detailed performance information must be

obtained from catalogs or from the manufacturer of the coil or heating unit,

so that a qualified system designer may analyze the possibility of utilizing

existing heat transfer equipment in a solar retrofit.

The performance of existing natural convective and radiant heat transfer

equipment is influenced by:

1) Supply water temperature

2) Water flow rate

3) Room air or radiant surface temperature

4) Unit construction

5) Surface area

Radiant units additionally are influenced by their surface emissivity, but

this effect is not significant.

The major factor influencing the capacity of these units is supply water

temperature, with water flow rate playing a minor role. Table 20 shows

correction factors that can be applied to these units to determine their offdesign capacity. However, it probably will be necessary to replace existing

units with ones of greater surface area. Substitution of single row baseboard

units with double row units as shown in figure 10 is one convenient

alternative.

D-26
ENTERING ENTERING WATER TEMPERATURES , F

|

| AIK

TEMP F 95 100 110 120 130 140 150 160 170 180 190 200 210 220

40 .458 .500 .583 .666 .75 .833 .917 1.00 1.08 1.16 1.25 1.33 1.42 1.50

50 .375 .417 .500 .583 .666 .75 .835 .917 1.00 1.08 1.16 1.25 1.33 1.42

60 .292 .333 .417 .500 .583 .666 .750 .835 .917 1.00 1.08 1.16 1.25 1.33

70 .208 .250 .333 .417 .500 .583 .666 .750 .835 .917 1.00 1.08 1.16 1.25

80 .125 .167 .250 .333 .417 .500 .583 .666 .750 .835 .917 1.00 1.08 1.16

NOTE: These Factors as baaed on constant GPM.

CAPACITY CORRECTION FACTORS FOR ENTERING CONDITIONS

OTHER THAN 60 F EAT AND 180 F EWT

TABLE 19 [7]

DOUBLE ROW BASEBOARD UNIT

FIGURE 10 [7]

D-27
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D.5.2.9 Solar Heating and Cooling Schematic Drawings

One of the most important elements in evaluating the suitability of a building for proposed solar retrofit is available space. In addition to the

solar collectors on the roof, considerably space is needed for auxiliary

equipment, some of which is both large and heavy. The equipment required

will depend upon the type of solar system being considered and its relationship to existing heating and air conditioning equipment. In particular,

space will be required for heat storage units, pumps, air handlers, and heat

exchangers

.

The following figures no. 11-15 identify the kinds of equipment needed for

only a few of the possible solar heat configurations which are in general

use. Included is a schematic drawing of the operating modes for one type of

heat collector system. Before deciding what specific space is needed for

solar heating, it is important to consult with a competent solar system

designer. The kinds and configuration of equipment chosen will vary between

designers, and will be strongly influenced by the existing system and its

components, the character of load, location of building, and other factors.

D-29
FIGURE 11 [7]

Auxiliary Furnace

Solar Collector

Differential Thermostat

Controller

Collector Loop

WATER-BASED SYSTEM WITH TANK STORAGE

FIGURE 12 [7] D-30

APPENDIX D.

6

Plumbing Systems

D-32
D. 6 PLUMBING SYSTEMS

D. 6. 1 GENERAL

This section covers specific tests to be used for further evaluation of

existing plumbing systems being considered for adaptation to solar retrofit.

Instructions for visual inspection of the systems and a check list of

potential problems were incorporated in section 5 of this report.

D.6.2 GUIDELINES

D.6.2.1 Test for Leaks in Water Supply System [38]

A simple method for checking on the presence of leaks in the water supply

lines of the building follows:

1) Close the valves to all plumbing fixtures on the supply line.

2) Be sure the main water supply valve is fully open.

3) Listen for a gurgling or murmuring sound in the supply pipe. Hold a rod against the ear, and make contact with the other end of the rod

at various points along the system, to pin point suspected leaks.

4)

If no leak can be determined in any of the interior supply lines,

and a leak still is suspected, listen for signs of leakage in the

supply pipe leading from the water main outside the building. Also

invite the water company to investigate their supply lines if

gurgling or running water sounds persist.

D.6.2. 2 Test of Supply Piping [38]

Clogged water supply pipes often cause a reduction in water pressure at the

faucets. Adequacy of the pressure may be checked as follows:

1) Open top floor lavatory and sink faucets.

2) Open bathtub faucets and flush the toilets. If the flow of water

in the top floor fixtures is reduced substantially, the piping may

be of inadequate size or badly clogged with scale, assuming there

is normal pressure at the water supply.

D. 6.2.3 Water Test for Leaks in Drain, Waste and Vent (DWV ) System

[60, 61, 62]

A standing water test of the DWV system is a simple method for testing for

leaks in the drain piping. A suitable plug can be inserted in the clean out

at the lowest point of the system, and each water closet and P-trap can be

plugged, thereby creating a closed DWV system. With at least a 10 foot head

of standing water in the vent piping for 30 minutes or more, the DWV piping

system can be checked for leaks to determine whether parts of the piping need

D-33
to be replaced. A partial inspection behind a wall may be made through

suitable openings such as electrical wall outlets, or by removing the

baseboard

.

D.6.2.4 Air Test for Leaks in DWV System [61, 62, 63]

An alternate test for leakage in the DWV piping consists of plugging all

terminals, including open vents in the system, and compressing the air in the

system to at least 10” Hg (or 5 psi) for 15 minutes to see whether the system

will hold the pressure. Leaks may be detected by listening for leaking air,

or by using a soap bubble test.

D.6.2.5 Siphonage of Traps [64, 65, 66, 67, 68, 69, 70, 71, 72]

Where several plumbing fixtures are connected to a single horizontal drain, or a drain empties into a vertical stack which also carriers effluent from

floors above, there exists the possibility that the movement of waste in the

system will induce siphonage in the system (i.e., removal of the water seal

from traps). Too little water remaining in a fixture trap may permit vermin

or sewer gas entering the building through the trap.

In testing for siphonage, one or more fixtures are filled to overflowing and

discharged. The remaining level of water in the trap seal of each fixture

is then measured to determine the depth of seal retention. At least 50 percent or 25 mm (1 in) of the original seal depth should be retained in all

fixtures. If excessive siphonage occurs, the drain lines and connections

should be cleaned, enlarged, properly vented, or otherwise modified.

If an existing building is being considered for solar retrofit, the entire

drainage system should be examined (and tested if necessary) under the supervision of experienced plumbing officials, to assure compliance with the

health and safety requirements of the appropriate plumbing code.

D-34
APPENDIX D.

7

Electrical Systems

D-35
D. 7 ELECTRICAL SYSTEMS

D. 7. 1 GENERAL

Section 6 of this report covered the preliminary evaluation of existing

electrical systems, and consisted primarily of visual inspection of the systems. This section includes actual tests to be performed on the systems,

utilizing instruments. Consequently, experience with certain high voltage

instruments, and a greater amount of time and judgment will be required.

D. 7.2 GUIDELINES

D.7.2.1 Megohm Test (Megger Tester) for Electrical Insulation [38, 73]

If the insulation appears to be deteriorated (crumbling or cracking), it is

always best to replace the wiring. If there is a question regarding the

adequacy of the insulation, the megohm test may be used to check it. In

this test, the wires for each circuit are disconnected at the power supply,

and a "Megger" tester is used to apply test voltages to the branch circuits.

Branch circuits should read at least one megohm to ground. If lights or appliances are included in the branch circuit, readings should exceed

500,000 ohms. (Feeders should be tested in accordance with Article 110-20

of the National Electrical Code.) If there are any low resistance readings

or indications of shorts in the circuit, the insulation is considered faulty,

and the circuit wiring should be replaced. Because high voltages are used

and experienced judgment is needed, only a qualified electrician should

perform the test.

D.7.2.2 Voltage Drop Determination [74]

The measure of voltage drop in a branch circuit under normal load is'a good

indicator of excessive impedance (e.g., excessive length) of the circuits.

Conductors in branch circuits will perform more efficiently if the following

conditions are met:

1) The voltage drop at the farthest outlet for power, heating and

lighting loads does not exceed 3 percent.

2 ) The maximum total voltage drop in feeders and branch circuits to

the farthest outlet does not exceed 5 percent.

If voltage drops are much in excess of these values, the circuit needs

replacement. Generally, ordinary voltmeters may be used for determining

voltage drops in the circuits. Because measurements must be made under load

(with the current also being measured) only a qualified person should undertake

the tests.

D.7.2.3 Circuit Analyzer for Circuit Faults [75]

A commercially available electrical analyzer is available to determine various

faults in existing wiring systems. It was originally developed for testing

D-36
newly wired circuits, but it also may be used for assessing performance of

existing systems. The circuit analyzer will check the following circuit

conditions

:

1) Open ground

2) Open hot

3) Open neutral

A) Hot/ground reversed

5) Hot/ neutral reversed

Measurements obtained will indicate only design or operating faults such as improper connections. The analyzer will not determine the condition of the

materials which make up the branch circuit. The manufacturer's instructions

must be followed in using the analyzer and interpreting the readings, and

only a qualified person should conduct the tests. The analyzer can be used

on two-wire circuits by utilizing a special adapter.

D.7.2.4 Circuit Breaker and Resistance Tester [76]

A commercial circuit breaker and resistance tester is available also for

evaluating circuit breakers by simulating an overload condition as a proof

test of the circuit breaker. A special component comes with the instrument

which may be used for evaluating resistance of windings (and other equipment

resistances) in the range of 1 megohm to 1000 megohms. The current is limited

to five milliamperes for maximum safety. The resistance tester is intended

to indicate potential breakdown in electrical resistance of insulating

materials

.

Circuit breakers are tested with the breaker removed from the panel. If

there is no master disconnect, the utility company should be asked to cut

off service during removal of the breaker. Only a qualified electrician

should be engaged to conduct the tests.

r

D-37
N BS-114A (rev. 2 «ec) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBSIR 81-2289

2. Performing Organ.- Report No. 3. Publication Date

July 1981

4. TITLE AND SUBTITLE

Preliminary Guidelines for Condition Assessment of Buildings Being Considered

for Solar Retrofit

5. AUTHOR(S)

Frank H. Lerchen. James H. Pielert. Phillip T. Chen

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions)

NATIONAL bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

NBSIR/Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

U.S. Department of Energy

Office of Solar Applications for Buildings

Office of the Assistant Secretary

Conservation and Renewable Energy

I Washington. D.C. 20585

10. SUPPLEMENTARY NOTES

Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here)

This report was developed to help Federal agencies determine if buildings in their

inventory are suitable for solar energy retrofit. It describes evaluation methods

which are available to the facilities engineer to assist in determining whether the

building and its systems (structural, HVAC, plumbing, and electrical) can be retrofitted with solar energy equipment under the Solar Federal Buildings Program (SFBP)

.

Techniques for preliminary on-site inspection are emphasized, while more detailed

evaluation techniques are described briefly and are referenced further.

The report describes evaluation methods available specifically for use with the

structural materials of concrete, steel, masonry, and wood, as well as for use with

the heating/ventilating/air conditioning, plumbing, and electrical supportive systems

Comparative tables are provided for each building material to aid the reader in

making a quick selection of the evaluation method most appropriate for the parameter tc be tested. In addition, checklists are provided which identify common problems

associated with each building material, possible causes of the problem, and the

potential impact of the problem on the existing building systems and the solar retrofit

system.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

Building rehabilitation; concrete; electrical; evaluation; HVAC; masonry; plumbing;

steel; solar; structural systems; test methods; wood

13. AVAILABILITY

Ix l Uni imited

] | For Official Distribution. Do Not Release to NTIS

Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

LVt Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

138

15. Price

USCOMM-DC 6043-P80
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