NBSIR 83-2768

Interim Report on NBS Thermal

Integrity Diagnostic Tests on

Eight GSA Federal Office Buildings

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Washington, DC 20234

September 1 983

3C

100

Prepared for: ublic Building Service

eneral Services Administration

/ashington, DC 20405

NBSIR 83-2768

INTERIM REPORT ON NBS THERMAL

INTEGRITY DIAGNOSTIC TESTS ON

EIGHT GSA FEDERAL OFFICE BUILDINGS

Richard A. Grot

Yui-May L. Chang

Andrew K Persily

Jin B. Fang

U S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Washington, DC 20234

September 1 983

Prepared for: Public Building Service

General Services Administration

Washington, DC 20405

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

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Abstract

This report summarizes preliminary results of diagnostic tests to evaluate the

thermal integrity of eight federal office buildings located throughout the

country. The test results include tracer gas measurements of air infiltration

rates, pressurization tests of the airtightness of the building shell, and

inspections of the envelope employing infrared thermography. In addition, the

thermal U-values of exterior walls were measured with both heat flow meters and a portable calorimeter box. The data collected on these buildings are still

undergoing analysis and therefore are to be considered preliminary.

Key Words: air infiltration; building diagnostics; building thermal integrity;

fan pressurization; field measurements; thermographic inspections;

tracer gas techniques; U-value tests

iii
Preface

This work was sponsored by the Public Building Service of the General Services

Administration through an interagency agreement with the National Bureau of

Standards, Interagency Agreement No. PBS-80-1.
TABLE OF CONTENTS

PAGE

Abstract iii

Preface iv

List of Tables vi

List of Figures vii

1. Introduction 1

2. Descriptions of the Buildings 1

3. Air Infiltration and Building Tightness Tests 10

4. Ground Infrared Thermographic Surveys 21

4.1 Background

4.2 Summary of Results

5. Determination of the Thermal Resistances of the Building Envelope 39

Using Heat Flow Meters and a Portable Calorimeter

6. Conclusions 42

7. Acknowledgements 43

8. References 44

v
List of Tables

Table 1. Location of Tracer Gas Sampling

Table 2. Airtightness Measurements on the Buildings

Table 3. Typical One-Hour Decay Test for Anchorage

Table 4. Typical One-Hour Decay Test for Springfield

Table 5. Typical One-Hour Decay Test for Norfolk

Table 6. Typical One-Hour Decay Test for Huron

Table 7. Typical One-Hour Decay Test for Columbia

Table 8. Data Files for Ann Arbor Building with No Outside Air Intake

Table 9. Data Files for Ann Arbor Building with Outside Air Intake

Table 10. Thermal Deficiencies Observed in Each Test Building

Table 11. Construction of External Walls of Test Buildings

Table 12. Comparison of Measured Wall Thermal Resistances and Corresponding

Predicted Values
List of Figures

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

Figure

1. Location of the Eight Federal Office Buildings

2. Schematic Diagram and Photograph of Federal Building in Anchorage

3. Schematic Diagram and Photograph of Federal Building in Springfield

4. Schematic Diagram and Photograph of Federal Building in Columbia

5. Schematic Diagram and Photograph of Federal Building in Norfolk

6. Schematic Diagram and Photograph of Federal Building in Pittsfield

7. Schematic Diagram and Photograph of Federal Building in Huron

8. Schematic Diagram and Photograph of Federal Building in Ann Arbor

9. Schematic Diagram and Photograph of Federal Building in Fayetteville

10. Natural Air Infiltration Rates Versus Induced Air Exchange Rate

at 25 Pa

11. Distribution of Surface to Volume Ratio Among Federal Buildings

and Residences

12. Comparison of Ranks of Pressurization Test Results

13. Thermal Defects Observed in the Anchorage Building

14. Thermal Defects Observed in the Ann Arbor Building

15. Thermal Defects Observed in the Columbia Building

16. Thermal Defects Observed in the Fayetteville Building

17. Thermal Defects Observed in the Huron Building

18. Thermal Defects Observed in the Norfolk Building

19. Thermal Defects Observed in the Pittsfield Building

20. Thermal Defects Observed in the Springfield Building

Vll

1. Introduction

In order to assess the usefulness of various diagnostic procedures for the

assessment of the thermal integrity of the envelope of federal office buildings,

the National Bureau of Standards performed a series of diagnostic tests on eight

federal office builidngs during the period from September 1982 to May 1983.

These buildings were located in Anchorage, AK, Columbia, SC, Norfolk, VA,

Springfield, MA, Pittsfield, MA, Huron, SD, Ann Arbor, MI, and Fayetteville, AR.

The tests which were performed on these buildings consisted of: fan

pressurization to assess the tightness of the building envelope, tracer gas

measurements of the natural air infiltration rates and ventilation rates of the

buildings, ground based infrared thermography, aerial thermography, inspection of

the buildings with spot radiometers, determination of the thermal conductance or U-value using heat flow meters and a portable calorimeter, and leakage testing of

the components of the building. A detailed technical description of these test

methods can be found in the report of the first phase of this project 1

. The

purpose of the present report is to summarize the data collected and analyzed

from the fan pressurization tests, the tracer gas tests, the thermographic

inspections and the U-value tests. To date NBS has been able to carry out all

tests envisioned in the first phase of this project with the exception of the use

of the Envelope Thermal Testing Unit (ET'IU) developed by Lawrence Berkeley

Laboratories for measuring the dynamic response of walls. This device will not

be available to NBS until the late summer of 1983.

2. Description of the Buildings

The eight federal office buildings are located in the cities shown in the map in

figure 1. In general these are new buildings (less than 3 years old) constucted

to the U.S. federal energy guidelines of less than 630 MJ/m^ per year of on-site

energy and less than 1200 MJ/nr per year of off-site energy. The building in

Fayetteville, AR is 7 years old and was built before this energy guideline for new federal office buildings was in effect. Though these buildings tend to

perform better than most existing federal office buildings, none has met the

energy guidelines during its first few years of occupancy. For the purpose of

this study the buildings in Anchorage, AK; Springfield, MA; Norfolk, VA; and

Columbia, SC are considered large office buildings (over 10,000 nr of occupiable

floor area). Columbia is 15 stories high, Norfolk 8 stories. Anchorage between 2

and 6 depending on the module, and Springfield 5 stories. The buildings in

Pittsfield, MA; Huron, SD; Ann Arbor, MI; and Fayetteville, AR are considered

small office buildings (less than 10,000 nr of floor area). These small office

buildings range in height from 2 to 5 stories. Schematic diagrams and a photograph of each building are given in figures 2 through 9. All but two of the

buildings have variable volume air handlers in the major zones of the buildings.

They are heated by perimeter heating systems which are generally hydronic. The

building in Columbia has two perimeter heating systems. In the Norfolk building,

heaters and air conditioners have been added to the air system on floors which

proved difficult to heat and cool. They all have central chiller systems for

cooling the core spaces of the buildings. The buildings in Anchorage and

Springfield have underground garages. The Norfolk building has an exterior

garage.

1
Figure 1. Location of the Eight Federal Office Buildings

ANCHORAGE FEDERAL BUILDING

Schematic of Overhead view

Figure 2. Schematic Diagram and Photograph of Federal Building

in Anchorage, AK

2
SPRINGFIELD FEDERAL BUILDING

Schematic of South Elevation SPRINGFIELD FEDERAL BUILDING

Manpu itcatiaa Schematic of First Floor

Oatliac af Atrlaai

Figure 3. Schematic Diagram and Photograph of Federal Building

in Springfield, MA

3
COLUMBIA FEDERAL BUILDING

Schematic af Eaat Elavatlaa

COLUMBIA FEDERAL BUILDING

Figure 4. Schematic Diagram and Photograph of Federal Building

in Columbia, SC

4
NORFOLK FEDERAL BUILDING

Schematic of West Elevation

a Saapla location Oatliaa af outsida garaga aa apgaaita sida af baildii

Maia ratara *Machaaical Paatbaasa

r

a Itb Flaar

a 7tb Flaar a Itb Flaar a Etb Flaar a dtb Flaar

1 a 3 r j Flaar

j * 2nd Flaar Opaa

j *1stFDaar

NORFOLK FEDERAL BUILDING

Schematic of North Elevation

Figure 5. Schematic Diagram and Photograph of Federal Building

in Norfolk, VA

5
Figure 6

PITTSFIELD FEDERAL BUILDING

Schematic of Weet Elevation

A laapla laiatlaaa

PITTSFIELD FEDERAL BUILDING

Schematic of Overhead View

Schematic Diagram and Photograph of Federal Building

in Pittsfield, MA

6
HURON FEDERAL BUILDING

Schematic of East-West Building Section

* Saapl* locatlaas

’North" Wing A A ’East* Wing

4th Floor north a A

4th Floor oast

3rd Floor north a 4 3rd Floor aaat

2nd Floor aorth a 4 2nd Floor oast

1st Floor north* a 1st Floor oast

HURON FEDERAL BUILDING

Schematic of Overhead View

North Wing

East Wing

Figure 7. Schematic Diagram and Photograph of Federal Building

in Huron , SD

7
ANN ARBOR FEDERAL BUILDING

Schematic of East Elavation

ANN ARBOR FEDERAL BUILDING

Scksnatlc af First Flaar

Figure 8. Schematic Diagram and Photograph of Federal Building

in Ann Arbor, MI

8
FAYETTEVILLE FEDERAL BUILDING

Schematic of North Elevation

Schematic of First Floor

Figure 9. Schematic Diagram and Photograph of Federal Building

in Fayetteville, AR

9
3. Air Infiltration and Building Tightness Tests

The air infiltration and building tightness of the eight federal office buildings were tested using whole building fan pressurization and tracer gas techniques.

The fan pressurization tests were performed during the fall of 1982 on seven of

the eight federal buildings using the building's HVAC system fans. It was not

possible to pressurize the federal building in Fayetteville because the outside

air duct could not bring in a sufficient volume of air due to its limited size.

This building could be pressurized with an external fan however the shipment of

this fan to Fayetteville was judged to be too expensive. The air infiltration

under natural conditions was measured using sulfur hexafluoride (SF^) as a tracer. This test was designed for each building to produce a measure of the

total air infiltration rate of the building and the rates of the major zones of

the building. Sample and injection tubing was installed in each zone along with

wiring for measurng interior temperatures, the status of the building's HVAC fans

and exterior weather conditions (wind speed, wind direction and exterior

temperature). The automatic air infiltration system previously designed by NBS

for large buildings was installed in each building for a period of about a week

during the fall, winter and spring (three automated air infiltration systems were

used on this project) 2

. Tests were performed both during periods of occupancy

and non-occupancy, and with the dampers opened and closed. To date, tracer gas

infiltration meaurements have been made for a total of about 200 hours in each

building. The air sample locations for these tests are given in table 1, and

shown in the schematics in figures 2 through 9.

The results of the pressurization tests and the fall tracer gas air infiltration

measurements (dampers closed) are shown in table 2. The most notable aspect of

these data is the tightness of the buildings from the pressurization measurements.

The pressurization test results are the air flow rates into the buildings, in

units of building volumes or exchanges per hour, required to sustain a 25 Pa

pressure difference between inside and outside. These induced 25 Pa flow rates

are significantly larger than the ventilation rates during normal building

operation or infiltration rates induced by weather. The 50 Pa exchange rates of

the buildings are roughly 1.5 times the 25 Pa rates shown in the table. These 50

Pa leakage rates are very low compared to those measured in homes. U.S. homes

generally range from about 5 volumes per hour (tight) to greater than 20 (very

leaky). Swedish and Canadian homes are being built with 50 Pa flow rates of less

than 2 volumes per hour. Thus, the 50 Pa flow rates of these federal buildings

correspond to very tight homes.

10
Table 1. Location of Tracer Gas Sampling

Anchorage

1. Module A

2. Module B

3. Module C

4. Module D

5. Module E

6. Module F

7. 5th Floor Module C

8. 3rd Floor Module C

9. 1st Floor Module C

Springfield

1. North Return

2. South Return

3. Atrium/Lobby

4. 5th Floor - North

5. 4th Floor - North

6. 3rd Floor - North

7 . 2nd Floor - North

8. 1st Floor - North

9. 4th Floor - South

10.2nd Floor - South

Ann Arbor

1. HVAC Return

2. 4th Floor Return

3. 3rd Floor Return

4. 1st & 2nd Floor Return

5. Lobby

6. Post Office

Huron

1. North Return

2. East Return

3. 4th Floor - North

4. 3rd Floor - North

5. 2nd Floor - North

6. 1st Floor - North

7. 4 th Floor - East

8. 3rd Floor - East

9. 2nd Floor - East

10 .1st Floor - East

Columbia

1 . HVAC Return

2. 13th Floor

3. 11th Floor

4. 9th Floor

5. 7th Floor

6. 5th Floor

7. 3rd Floor

8. 1st Floor & Basement

9 . Lobby

10.

Courthouse

Norfolk

1. HVAC Return

2. 8th Floor

3. 7th Floor

4. 6th Floor

5. 5th Floor

6. 4th Floor

7. 3rd Floor

8. 2nd Floor

9. 1st Floor

Fayetteville

1. 1st Floor

2. 2nd Floor

3. 3rd Floor

4. 4th Floor

5. 5th Floor

6. Courtroom - 5th Floor

Pittsfield

1. 1st Floor Return

2. 2nd Floor Return

11
Table 2. Air tightness Measurements on the Federal Buildings

Building

Location

Floor Area

(m^)

Pressurization

Flow at 25 Pa

(volumes/hour)

Tracer Gas Decay

Infiltration Rate

(volumes/hour)

Anchorage 45,490 0.80 0.20 to 0.30

Ann Arbor 4,900 0.86 0.55 to 0.65

Columbia 20,070 0.67 0.35 to 0.45

Fayetteville 3,400 — 0.35 to 0.45

Huron 6,420 0.45 0.10 to 0.20

Norfolk 17,250 1.36 0.45 to 0.55

Pittsfield 1,730 1.07 0.25 to 0.35

Springfield 13,530 1.00

k 0.30 to 0.40

* The values listed correspond to a range of measured infiltration rates with

wind speeds less than 1.5 m/s and an outside temperature between 5 and 10 °C.

12
Table 1. Location of Tracer Gas Sampling

Anchorage

1. Module A

2. Module B 3. Module C

4. Module D

5. Module E

6. Module F

7. 5th Floor Module C

8. 3rd Floor Module C

9. 1st Floor Module C

Springfield

1. North Return

2. South Return

3. Atrium/Lobby

4. 5th Floor - North

5. 4th Floor - North

6. 3rd Floor - North

7. 2nd Floor - North

8. 1st Floor - North

9. 4th Floor - South

10.2nd Floor - South

Ann Arbor

1. HVAC Return

2. 4th Floor Return

3. 3rd Floor Return

4. 1st & 2nd Floor Return

5. Lobby

6. Post Office

Huron

1. North Return

2. East Return

3. 4th Floor - North

4. 3rd Floor - North

5. 2nd Floor - North

6. 1st Floor - North

7. 4th Floor - East

8. 3rd Floor - East

9. 2nd Floor - East

10 .1st Floor - East

Columbia

1. HVAC Return

2. 13th Floor

3. 11th Floor

4. 9th Floor

5. 7th Floor

6. 5th Floor

7. 3rd Floor

8. 1st Floor & Basement

9 . Lobby

10.

Courthouse

Norfolk

1 . HVAC Return

2. 8th Floor

3. 7th Floor

4. 6th Floor

5. 5th Floor

6. 4th Floor

7. 3rd Floor

8. 2nd Floor

9. 1st Floor

Fayetteville

1. 1st Floor

2. 2nd Floor

3. 3rd Floor

4. 4th Floor

5. 5th Floor

6. Courtroom - 5th Floor

Pittsfield

1. 1st Floor Return

2. 2nd Floor Return

11
Table 2. Airtightness Measurements on the Federal Buildings

Building

Location

Floor Area

(m^)

Pressurization

Flow at 25 Pa

(volumes/hour)

Tracer Gas Decay

Infiltration Rate

(volumes/hour)

Anchorage 45,490 0.80 0.20 to 0.30

Ann Arbor 4,900 0.86 0.55 to 0.65

Columbia 20,070 0.67 0.35 to 0.45

Fayetteville 3,400 — 0.35 to 0.45

Huron 6,420 0.45 0.10 to 0.20

Norfolk 17,250 1.36 0.45 to 0.55

Pittsfield 1,730 1.07 0.25 to 0.35

Springfield 13,530 1.00 0.30 to 0.40

* The values listed correspond to a range of measured infiltration rates with

wind speeds less than 1.5 m/s and an outside temperature between 5 and 10 °C.

12
Table 7. Typical One-Hour Decay Tests for Columbia

FEDERAL BUILDING - COLUMBIA

MAX CURRENT = 1708 MIN CURRENT = EXTERIOR TEMP. = 14.6 C WIND SPEED = 1 . 0 M/S

+/- .1 C +/- .6 M/S

11 / 19/82 0

1660

WIND DIR. = 157. DEG.

INTERIOR TEMPERATURES

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COURT

27.6 27.7 27.2 27.5 27.2 26.6 26.3 22.2 21.7 24.3 C

+/- .4 O. O 0.0 0.0 0.0 . 1 0 . 0 0 . 0 . 1 0 . 0 C

HV AC FAN OPERATION

TOWER 1ST -BAS COU RT

0 0 0 SEC

TRACER CONCENTRATIONS

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COU RT

0:00 96.1 94.4 85.6 91.3 85.0 84.9 92.2 32.9 33.3 44.9 ppb

0: 10 86.3 89.8 80.5 88.0 84.6 80.5 91.0 28.

1

29.0 42.3 PPb

0:20 82. O 86.5 78.2 85.5 79.4 78.3 89.2 27.8 26.4 39.8 ppb

0:30 78.4 83.6 74.0 80. 8 78.6 75.7 84.2 24.5 25.0 37.6 ppb

0:40 75.5 80.5 70.6 77.2 72.0 69.8 79.7 23.8 22.4 35.8 ppb

INFIL .27 .22 .27 .27 .30 .28 .27 .37 .50 .34 /HR

17
Table 8. Data Filee for Ann Arbor Building with Mo Outside Air Intake

CITY AND BUILDING : FEDERAL BUILDING - ANNARBOR

CONDITION : 0% OUTSIDE AIR

CONDITION : VENTS UNSEALED

CONDITION : WIND DATA

DATE

2/ 4/83

HOUR

18

W. SPEED

1.4

W. DIR

270.0

T. OUT

1.4

T. IN

22.9

T.DIFF

21.5

AI. AVE

.86

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= .47

= .71

= .39

= .57

= .76

= 2.28

DATE

2/ 4/83

HOUR

19

W. SPEED

1.1

W. DIR

270.0

T. OUT

1.8

T. IN

22.7

T.DIFF

20.9

AI. AVE

.95

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= 1.24

= 1.01

= .54

= .52

= .97

= 1.43

DATE

2/ 4/83

HOUR

20

W. SPEED

1.0

W. DIR

270.0

T. OUT

1.5

T. IN

22.5

T.DIFF

21.0

AI. AVE

.81

HVAC

4TH F

3RD F

1&2 F

LOB . P.O.

= .62

= .42

= .62

= .58

= 1.22

= 1.37

DATE

2/ 4/83

HOUR

21

W. SPEED

1.0

W.DIR

270.0

T. OUT

.8

T. IN

22.3

T.DIFF

20.8

AI. AVE

.93

HVAC

3RD F

1&2 F

LOB . P.O.

= .54

= .64

= .66

= 1.53

= 1.26

DATE

2/ 4/83

HOUR

22

W. SPEED

.8

W.DIR

270.0

T. OUT

1.4

T. IN

22.1

T.DIFF

20.7

AI. AVE

.82

HVAC

4TH F

3RD F

1&2 F

LOB . P.O.

= .61

= .57

= .64

= .62

r 1.27

= 1.23

18
Table 7. Typical One-Hour Decay Tests for Columbia

FEDERAL BUILDING - COLUMBIA 11/19/82 0

MAX CURRENT = 1708 MIN CURRENT = 1660

EXTERIOR TEMP, r 14.6 C WIND SPEED = 1.0 M/S WIND DIR. = 157. DEG.

+/- .1C +/- .6 M/S

INTERIOR TEMPERATURES

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COURT

27.6 27.7 27.2 27.5 27.2 26.6 26.3 22.2 21.7 24.3 C

+/- .4 0.0 0.0 0.0 0.0 .1 0.0 0.0 .1 0.0 C

HV AC FAN OPERATION

TOWER 1ST-BAS COURT

0 0 0 SEC

TRACER CONCENTRATIONS

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COU RT

0:00 96.1 94.4 85.6 91.3 85.0 84.9 92.2 32.9 33.3 44.9 ppb

0:10 86.3 89.8 80.5 88. 0 84.6 80.5 91.0 28.

29.0 42.3 ppb

0:20 82. 0 86.5 78.2 85.5 79.4 78.3 89.2 27.8 26.4 39.8 ppb

0:30 78.4 83.6 74.0 80. 8 78.6 75.7 84.2 24.5 25.0 37.6 ppb

0:40 75.5 80.5 70.6 77.2 72.0 69.8 79.7 23.8 22.4 35.8 ppb

INFIL .27 .22 .27 .27 .30 .28 .27 .37 .50 .34 /HR

17
Table 8. Data Files for Ann Arbor Building with No Outside Air Intake

CITY AND BUILDING : FEDERAL BUILDING - ANNARBOR

CONDITION : OX OUTSIDE AIR

CONDITION : VENTS UNSEALED

CONDITION : WIND DATA

DATE

2/ 4/83

HOUR

18

W. SPEED

1.4

W. DIR

270.0

T. OUT

1.4

T. IN

22.9

T.DIFF

21.5

AI. AVE

.86

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= .47

= .71

= .39

= .57

= .76

= 2.28

DATE

2/ 4/83

HOUR

19

W. SPEED

1.1

W.DIR

270.0

T. OUT

1.8

T. IN

22.7

T.DIFF

20.9

AI. AVE

.95

HV AC

4TH F

3RD F

1&2 F

LOB.

P.O.

= 1.24

= 1.01

= .54

= .52

= .97

= 1.43

DATE

2/ 4/83

HOUR

20

W. SPEED

1.0

W.DIR

270.0

T. OUT

1.5

T. IN

22.5

T.DIFF

21.0

AI. AVE

.81

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= .62

= .42

= .62

= .58

= 1.22

= 1.37

DATE

2/ 4/83

HOUR

21

W. SPEED

1.0

W.DIR

270.0

T. OUT

.8

T. IN

22.3

T.DIFF

20.8

AI. AVE

.93

HV AC

3RD F

1&2 F

LOB . P.O.

= .54

= .64

= .66

= 1.53

= 1.26

-

DATE

2/ 4/83

HOUR

22

W. SPEED

.8

W.DIR

270.0

T. OUT

1.4

T. IN

22.

T.DIFF

20.7

AI. AVE

.82

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= .61

= .57

= .64

= .62

= 1.27

= 1.23

18
The results of the tracer gas tests in table 2 indicate that the buildings in

Pittsfield, Huron and Anchorage are experiencing relatively low natural leakage

rates. The buildings with the highest natural rates are Ann Arbor and Norfolk.

Tables 3 through 7 show the results of typical one-hour decay tests for the

buildings in Anchorage, Springfield, Norfolk, Huron and Columbia. These tables

indicate the extent of tracer gas mixing obtained in these tests, with good

mixing being a requirement for accurate results. They also show zones of the

building which exhibit high air exchange rates compared to the rest of the

building - the lobby in Springfield, the 1st floor in Norfolk, and the lobby in

Columbia. Similar high rates can also be shown for the 1st floor in Fayetteville

and the lobby and post office in Ann Arbor. The lobbies generally exhibit larger

exchange rates due to the exterior doors in these zones and the people moving in

and out of the building. The post office in Ann Arbor has a large amount of such

pedestrian traffic, and large doors for loading and unloading mail.

The data in tables 3 to 7 are checked for accuracy and then stored in separate

files according to the condition of the vents and occupancy of the building.

Tables 8 and 9 show data from these files for the Ann Arbor building. Note the

large ventilation rates in table 9. These rates were measured under spring

conditions in which the outdoor air is cool enough to condition the building

without running the chillers.

From the data in table 2, it can be seen that there is correlation between the

pressurization measurements and the tracer gas test results. Bearing in mind

that the tracer gas results are preliminary and made only under approximately the same weather conditions, infiltration rates have been plotted against

pressurization results in figure 10. The correlation between the two

measurements appears to be fairly strong. The slope of a line passing through

all the points is roughly 0.5. If one adjusts the 25 Pa flows to 50 Pa flows

using the rough correction factor of 1.5, then the slope of infiltration against

50 Pa flow is about 1/3. This compares to the slope for residential buildings of

about 1/20.

In comparing the pressurization test results of the federal buildings to each

other and to residential buildings, the important factor of surface to volume

ratio arises. Figure 11 shows the surface to volume ratios (S/V) in m“^ for the

federal buildings and two sample homes. The 1-story house is assumed to have a 110 m

z square floor area and 2.5 m ceilings. The 2-story home also has a square

floor plan with 100 m^ on each floor and a 5 m building height. We see in the

figure that the large sizes of the federal buildings generally lead to lower

values of S/V than for homes. The Ann Arbor building is an exception due to its

particular design (see figure 8).

One may adjust the pressurization test results in table 1 to take into account

the different values of S/V among the buildings. Table 2 gives the 25 Pa leakage

rate in building volumes per hour. This number divided by S/V, yields the 25 Pa

flow rate in nrVhr per m^ of exterior surface area. This second flow rate is

more of a measure of "construction quality" than the first flow rate. Figure 12

compares these two measures of leakiness. The vertical scale on the left shows

the 25 Pa flows in exchanges per hour for the seven federal buildings and the two

sample houses (2.0 exchanges/hr at 50 Pa very tight). The vertical scale on the

right shows the 25 Pa flows in m^/hr-m^ as discussed above. We see that in

moving from exchanges/hr to m^/hr-m^ the tightness ranking of the buildings

changes significantly. Also, the spread in the leakage values using the second

measure is larger than the spread in exchanges per hour. The most significant

13
change occurs in the Ann Arbor building which is of average tightness as maasurad

by exchanges par hour but is tha tightest building in terms of ur/hr-m . Thus,

the Ann Arbor building has the tightest construction per m

2 of wall area, but its

design leads it to appear relatively leakier than many of the other buildings as measured by the flow in exchanges per hour.

14
Table 3. Typical One-Hour Decay Test for Anchorage

FEDERAL BLDG. - ANCHORAGE 1/ 7/83 12

MAX CURRENT = 1750 MIN CURRENT = 1708

EXTERIOR TEMP. = -18.2 C WIND SPEED = 3.9 M/S WIND DIR. = 135.

+/- .1C +/- .8 M/S

INTERIOR TEMPERATURES

MOD A MOD B MOD C MOD D MOD E MOD F 1ST C 3RD C 5TH C

22. 5 22. 3 0 . 0 0.0 23.3 23.5 22.6 22.7 22.7 C

+/- .7 . 1 0 . 0 0 . 0 0 . 0 0.0 .4 0 . 0 0 . 0 C

HV AC FAN OPERATION

MOD A MOD B MOD C MOD D MOD E MOD F

3599 3599 3599 3599 3599 3599 SEC

TRACER CONCENTRATIONS

MOD A MOD B MOD C MOD D MOD E MOD F 1ST C 3RD C 5TH C

12:00 114.6 108.9 101.1 91.8 78.2 81.4 68.2 86.5 103.3 PPb

12:10 105.0 98.2 99.9 88.2 76.1 77.7 62.3 78.6 97.4 ppb

12:20 102.6 96 .

92.4 83.2 73.7 74.6 49.9 76.6 97.6 ppb

12:30 93.9 90.

89.3 82.2 69.2 69.2 46.3 72. 8 130.3 ppb

12:40 91.2 84.3 79.0 76.8 65.

64.1 48.9 66.1 80.9 ppb

INFIL .31 .32 .44 .26 .32 .39 .48 .34 . 16 /HR

Table 4. Typical One-Hour Decay Test for Springf ield

FEDERAL BLDG. - SPRINGFIELD, M 12/ 2/82 0

MAX iCURRENT = 186 2 MIN iCURRENTi 1810

EXTERIOR TEMP • — 12. 1 C WIND SPEED = 1.3 M/S WIND DIR. = 247

+/- .1 C +/ .6 M/S

INTERIOR TEMPERATURES

NORTH SOUTH LOBBY N 5TH N 4TH N 3RD N 2ND N 1ST S 4TH S 2ND

23.4 24.3 27.8 24.7 23.7 23.4 23.0 24.3 24.5 24.3 C

+/- .2 . 1 0 . 0 . 1 . 1 . 1 . 1 . 1 . 1 0 . 0 C

HV AC FAN OPERATION

NORTH SOUTH ATRIUM

0 0 0 0 SEC

TRACER CONCENTRATIONS

NORTH SOUTH LOBBY N 5TH N 4TH N 3RD N 2ND N 1ST S 4TH S 2ND

0: 00 176.3 220. 0 177.0 161.2 156.7 155.9 159.9 135.4 215.6 203. 1 ppb

0:10 144.5 195.5 149.9 148.0 149.8 148. 0 146.1 128.6 206. 1 192. 8 ppb

0:20 138.4 179.2 140.8 142.3 138.7 141.5 133.1 121.4 196.1 177.0 ppb

0:30 130. 2 175.0 126.0 136.2 132.

134.1 131.3 109.9 185.4 176.3 ppb

0:40 127.6 164.6 119.9 123.9 121.9 129.6 126.1 109.4 173.8 166.9 ppb

INFIL . 26 .32 .47 .35 .40 .27 .27 .35 .34 .26 /HR

DEG

DEG,

15
Table 5. Typical One-Hour Decay Test for Norfolk

FEDERAL BUILDING - NORFOLK. VA 10/21/82 0

MAX CURRENT = 1665 MIN CURRENT = 1621

EXTERIOR TEMP. - 17.5 C WIND SPEED = 2.0 M/S WIND DIR. = 135. DEG.

+/- 0.0 c +/- .6 M/S

INTERIOR TEMPERATURES

RET 8TH F 7TH F 6TH F 5TH F 4TH F 3RD F 2ND F 1ST F

25.7 25.7 25.4 24.6 24.7 24.7 24.8 24.4 23.5 C

+/- .1 0.0 .2 0.0 0.0 0.0 0.0 0.0 0.0 C

HV AC FAN OPERATION

M HV AC 1ST FL

0 0 SEC

TRACER CONCENTRATIONS

RET 8TH F 7TH F 6TH F 5TH F 4TH F 3RD F 2ND F 1ST F

0:00 137.9 107.2 128.5 126.4 119.0 120.9 127.4 114.9 68.0 PPb

0:10 126.9 95.6 116.0 118.1 111.1 113.7 118.7 106.6 51.9 ppb

0:20 117.1 90.1 111.7 112.

1

106.5 106.6 112.7 93.8 49.3 ppb

0:30 111.1 84.1 101.7 106.9 96.9 97.1 105.7 86.4 36.5 ppb

0:40 101.7 77.3 97.9 98.0 92.7 88.2 98.4 79.7 30.0 ppb

INFIL .43 .42 .36 .36 .38 .51 .38 .57 1.17 /HR

Table 6. Typical One-Hour Decay Teat for Huron

FEDERAL BUILDING - HURON, S.D. 10/ 8/8 2 11

MAX CURRENT = 659 MIN CURRENT =611

EXTERIOR TEMP. = 10.2 C WIND SPEED = 1.5 M/S WIND DIR. = 135. DEG.

+/ — .6 C +/ - .9 M/S

INTERIOR TEMPERATURES

N RET E RET N 4TH N 3RD N 2ND N 1ST

26.0 24.4 25.9 27.0 26.0 24.6 C

+/- .6 0.0 .1 .3 .1 0.0 C

HV AC FAN OPERATION

ZONE 1 ZONE 2

594 595 SEC

TRACER CONCENTRATIONS

N RET E RET N 4TH N 3RD N 2ND N 1ST

11:00 99.8 121.4 99.5 95.2 96.9 93.1 ppb

11:10 89.8 88.8 89.9 87.9 86.0 86.9 ppb

11:20 82.7 77.6 83.5 84.8 82.9 84.4 ppb

11:30 82.

1

76.1 82.

1

81.3 82.4 81.6 ppb

11:40 78.6 75.1 81.4 80.9 80.8 78.3 ppb

INFIL .24 .31 .19 .17 .12 .21 /HR

16
Table 7. Typical One-Hour Decay Tests for Columbia

FEDERAL BUILDING - COLUMBIA 11/19/82 0

MAX CURRENT = 1708 MIN ICURRENT 1660

EXTERIOR TEMP. = 14.6 C WIND SPEED = 1.0 M/S WIND DIR. = I

1 +/- .1 C +/ .6 M/S

INTERIOR TEMPERATURES

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COURT

27.6 27.7 27.2 27.5 27.2 26.6 26.3 22.2 21.7 24.3 C

+/- .4 0 . 0 0 . 0 0.0 0 . 0 . 1 0.0 0 . 0 . 1 0 . 0 C

HV AC FAN OPERATION

TOWER 1ST-BAS COURT

0 0 0 SEC

TRACER CONCENTRATIONS

M RET 13 FL 11 FL 9 FL 7 FL 5 FL 3 FL 1ST-B LOBBY COU RT

0:00 96.1 94.4 85.6 91.3 85.0 84.9 92.2 32.9 33.3 44.9 ppb

0:10 86.3 89.8 80.5 88. 0 84.6 80.5 91.0 28.

29.0 42.3 PPb

0:20 82. 0 86.5 78.2 85.5 79.4 78.3 89.2 27.8 26.4 39.8 ppb

0:30 78.4 83.6 74.0 80. 8 78.6 75.7 84.2 24.5 25.0 37.6 ppb

0:40 75.5 80.5 70.6 77.2 72.0 69.8 79.7 23.8 22.4 35.8 ppb

INFIL .27 .22 .27 .27 .30 .28 .27 .37 .50 .34 /HR

I

I

DEG.

17
Table 8. Data Files for Ann Arbor Building with No Outside Air Intake

CITY AND BUILDING : FEDERAL BUILDING - ANNARBOR

CONDITION : OX OUTSIDE AIR

CONDITION : VENTS UNSEALED

CONDITION : WIND DATA

DATE

2/ 4/83

HOUR

18

W. SPEED

1.4

W.DIR

270.0

T. OUT

1.4

T. IN

22.9

T.DIFF

21.5

AI. AVE

.86

HV AC

4TH F

3RD F

1 &2 F

LOB.

P.O.

= .47

= .71

= .39

= .57

= .76

= 2.28

DATE

2/ 4/83

HOUR

19

W. SPEED

1.1

W.DIR

270.0

T. OUT

1.8

T. IN

22.7

T.DIFF

20.9

AI. AVE

.95

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= 1.24

= 1.01

= .54

= .52

= .97

= 1.43

DATE

2/ 4/83

HOUR

20

W. SPEED

1.0

W.DIR

270. 0

T . OUT

1.5

T . IN

22.5

T.DIFF

21.0

AI. AVE

.81

HV AC

4TH F

3RD F

1&2 F

LOB . P.O.

= .62

= .42

= .62

= .58

= 1.22

= 1.37

DATE

2/ 4/83

HOUR

21

W. SPEED

1.0

W.DIR

270.0

T. OUT

.8

T. IN

22.3

T.DIFF

20.8

AI. AVE

.93

HV AC

3RD F

1 &2 F

LOB . P.O.

= .54

= .64

= .66

= 1.53

= 1.26

DATE

2/ 4/83

HOUR

22

W. SPEED

.8

W.DIR

270.0

T. OUT

1.4

T . IN

22.1

T.DIFF

20.7

AI. AVE

.82

HV AC

4TH F

3RD F

1 &2 F

LOB . P.O.

= .61

= .57

= .64

= .62

= 1.27

= 1.23

18
Table 9. Data Files for Ann Arbor Building with Outside Air Intake

CITY AND BUILDING : FEDERAL BUILDING - ANN ARBOR

CONDITION : AIR INTAKE

CONDITION : VENTS UNSEALED

CONDITION : WIND DATA

DATE

5/25/83

HOUR

8

W. SPEED

1.8

W. DIR

157.5

T . OUT

15.0

T. IN

24.0

T.DIFF

9.0

AI. AVE

3.22

HV AC

4TH F

3RD F

2ND F

1ST F

LOB .

= 3.19

= 3.90

= 3.38

= 3.98

= 2.94

= 1.90

DATE

5/25/83

HOUR

9

W. SPEED

1.5

W.DIR

247.5

T. OUT

14.3

T . IN

23.8

T.DIFF

9.5

AI. AVE

2.11

HV AC

4TH F

3RD F

2ND F

1ST F

LOB .

= 2.51

= 1.82

= 2.58

= 2.51

= 1.25

= 1.97

DATE

5/25/83

HOUR

10

W. SPEED

2.0

W.DIR

270.0

T . OUT

13.8

T . IN

23.6

T.DIFF

9.8

AI . AVE

2.32

HV AC

4TH F

3RD F

2ND F

1ST F

LOB .

= 3.00

= 2.96

= 2.78

= 2.85

= .51

= 1.83

DATE

5/25/83

HOUR

11

W. SPEED

1.9

W.DIR

270. 0

T . OUT

13.8

T . IN

23.6

T.DIFF

9.8

AI. AVE

2.58

HV AC

4TH F

3RD F

2ND F

1ST F

LOB .

= 3.24

= 2.52

= 3.00

= 2.71

= 1.86

= 2.17

DATE

5/25/83

HOUR

12

W. SPEED

1.9

W.DIR

270. 0

T . OUT

14.2

T. IN

23.5

T.DIFF

9.3

AI. AVE

2.73

HV AC = 2.78

4TH F = 3.34

3RD F = 3.10

2ND F = 3.71

1ST F = 1.65

LOB . 1.79

19
Ann Arbor

</> UiH<

ACZ2

K

<P

0.6

0.4 -

0.6

Columbia

Norfolk

Sprlngflald

Plttaflald

0.1

0.1 -

Huron Wind apaad « 6 mph

Outalda tomparatura - 40-10'P

0

I I I 1 I I I I I I I I L O.t 1.0 PRISSURIZATION PLOW RATI AT II PA (aiehan«oa/tir)

1.1

Figure 10. Natural Air Infiltration Rates Versus

Induced Air Exchange Rates at 25 Pa

1.6

. —Ann Arbor

e

s

<

Plttaflald Huron

. ““Fayottovlllo —Norfolk

iprlngflald, Anchorage

Columbia AT II PASCAL PLOW AT 18 PASCAL PLOW

Figure 11. Distribution of Surface Figure 12. Comparison of Ranks

to Volume Ratio Among Federal of Pressurization Test Results

Buildings and Residences

20
4. Ground Infrared Thermographic Surveys

4.1 Background

Thermographic inspection by use of infrared (IR) imaging systems is a diagnostic

tool to locate thermal defects in a building envelope. IR thermography is a technique using non-contact scanning devices to convert the IR radiation from the

object surface to visible light by providing the image of the surface intensity

variation. The application of IR thermographic surveys to detect thermal

anomalies and to determine insulation effectiveness in large buildings permits

the selection of retrofit actions to be carried out to achieve energy

conservation. During field measurements, IR thermographic inspections are usually carried out both internally and externally under suitable weather

conditions. Thermographic data can be collected by photographing the thermal

image display of the thermographic sensing system or by recording the video

output of the system directly for subsequent reproduction. Information such as the temperature range of the sensing system and the environmental conditions

during inspection are also required to accompany the thermographic data. A copy

of such a thermal image, which corresponds to the apparent radiance temperature

distribution along the surface, is called a thermogram. A typical thermogram of

a surface will provide an intensity-modulated image where the bright and dark

portions represent the hot and cold regions, respectively, and the grey shades

show the intermediate range. Accordingly, the thermal integrity of the buildings

can be analyzed and interpreted from the thermograms and the documentation.

4.2 Summary of Results

Thermographic surveys were conducted during the heating season of 1982-83 at all

eight federal buildings. Since these are all large buildings, they were

inspected thoroughly by exterior surveys with interior surveys at some regions

where thermal anomalies were detected or suspected by outside inspections. A

summary of thermal deficiencies interpreted from the thermographic inspection for

all eight buildings is given in table 10. Note that the numerical calculations of

the total wall area and percentage of wall area subject to thermal defects in

table 10 exclude the glass and window areas of the outside surfaces. As

indicated in table 10, the most severe thermal defects that occur in these

buildings, besides defects in insulation, are air leakage through joints (wallto-wall, ceiling-to-wall, and f loor-to-wall) and window seals. Other common heat

loss locations observed include shrinkage of insulation, and air penetration

paths in walls and ceilings. The percentage of wall area subject to thermal

defects in these buildings was found to be between 6 and 18 percent, also given

in table 10. Descriptions of the thermal integrity and examples of defects

observed in the thermograms are included in the following discussion.

21
Table 10. Thermal Deficiencies Observed in Each Test Building

City ANCHR ANNAR COLUM FAYET HURON NORFK PITFD SPRFD

Total Wall

Area (m^) 7600 904 10584 1480 3561 6171 1013 4388

Defective Wall

Area (m^) 1405 159 1814 88 328 1067 187 303

% of Wall Area

Subject to

Thermal Defects

18 18 17 6 9 17 18 7

Defects Observed :

Walls

Lack of

Insulation * * * Shrinkage or Fissures in * * * * * Insulation

Cross Braces * * Air Penetration * * * * *

Ceilings

Interior * * * * Indentation

or Overhang * * * *

Doors *

Window

8

* * * *

Seam Leakage

Wall-Wall * * Floor-Wall * * * * Wall-Panels * * * *

Basement

Pipe or Duct * *

Thermal Bridges * * * *

22
Description of Thermal Defects in the Anchorage Federal Building

The Federal Building in Anchorage, AK, is rather uniform in its thermal

anomalies, for the defects in the modules are consistant and regular and the

modules are nearly identical to one another, discounting the differences in the

number of floors. The major defects are the thermal bridging at the panel

supports and the leakage that occurs at the seams of the interlocking panels,

especially at the corners and along the edges of the adjoining mirror walls, as illustrated in the thermograms from figures 13-1, 13-2, and 13-3. The mirror

walls in figure 13-1 appear with bands of light and dark as the light bands have

one-way mirrors for the floors inside and the dark bands have walls behind them.

The high rating, 18%, of wall area exposed to thermal defects is primarily due to

this corner leakage and thermal bridging at the structural supports of the

panels. Examples are the SW corner of the A module in figure 13-2 and the

vertical seams in figures 13-3 and 13-4. (The bright spot in the center of

figure 13-3 is the heat from a streetlight.) There also is extensive heat loss

from the first floor windows that are on every module as illustrated by the west

face of the A module in figure 13-4.

i 23
Figure 13. Thermal Defects Observed in the Anchorage Building

I «B0»* I

13-1

Mirror wall section

13-2

SW corner of

A module

13-3

SE corner with E wall,

upper floor F module

13-4

West face of the

A module

24
Description of Thermal Defects Observed in the Ann Arbor Federal Building

The Federal Building in Ann Arbor has many types of thermal anomalies, but the

predominant defect is the lack of insulation in large rectangular sections in the

east and west walls. Note the large heat loss areas in figures 14-2, 14-4, and

14-5. There are similar voids in the insulation in the wall outcroppings that

face east in the top center of the building as seen in figure 14-6. Leakage in

the seams is also a distinct problem in the building, as the heat loss is evident

in the thermograms of the adjoining panels in figures 14-1 and 14-2. The floorto-floor joints are sources of heat loss as well and are found in nearly all

exterior wall areas. The strong flaring in the close-up of the east wall at the

south end, as shown in figure 14-3, is indicative of serious thermal defects due

to air leakage in the top seams. Note the cross-brace in the thermogram of the

Post Office in figure 14-5 and some incompletely or unevely insulated walls in

figures 14-2 and 14-6 which the irregular voids indicate.

25
Figure 14. Thermal Defects Observed in the Ann t- rbor Building

14-3

E wall at the

S end

14-4

E wall at the

S end

14-5

E wall at the N

end, first floor

Post Office

14-6

N face above and to

the left of the front

entrance

26
Description of Thermal Defects in the Columbia Federal Building

The thermal anomalies observed in the Federal Building in Columbia, SC, consist

primarily of leakage through defects in the window panels and voids in the

insulation at the panel seams. The thermograms shown in figures 15-1 and 15-2

made by interior inspections illustrate some of the thermal defects, such as poor

insulation, missing insulation, and compression of insulation around the window

areas of this building. Figures 15-3 and 15-4 indicate the compression and voids

in the insulation in the north wall of the fourth floor by interior and exterior

thermograms, respectively. Similar defects over the entire building are the main

contributors to the high percentage, 17%, of wall area subjected to thermal

anomalies. Note the seam leakage in the panels that make up the solid edges in

figure 15-4. The heat loss depicted in figure 15-5 which rises up the west edge

of the south wall and across the top edge of the building is due to the perimeter

zone HVAC system ducts. The thermal integrity of the courthouse adjacent to the

tower is also imperfect. Figure 15-6 shows the leakage that occurs at the NW corner indent of the courthouse, which is typical of the leakage at those seams.

27
Figure 15. Thermal Defects Observed in the Col a Building

15-1

N wall on the fourth

floor of the tower

( interior)

15-3

SE corner of the

fourth floor

of the tower (int)

15-2

N wall on the fourth

floor of the tower

( interior)

15-4

Lower west face of the

tower at the N end

15-5

S face with W end

28

15-6

NW corner indent of the

courthouse
Description of Thermal Defects Observed in the Fayetteville Federal Building

Of all the Federal Buildings inspected, the wall areas of the Fayetteville

Building are observed to be relatively uniformly insulated, however this is

actually due to a lack of insulation in the exterior wall envelope. This

indicates the limitation placed on infrared methods when applied to uninsulated

walls. The leakage of the f loor-to-f loor seams are the prominent defects.

Examples are the seams of the elevator towers as shown in figures 16-1 and 16-3.

This type of thermal defect is also evident in the east and west walls below the

overhangs where the roof of the overhanging section appears to be a source of

heat loss as seen by the flaring against the tower in figure 16-1. Note that the

heat loss through the floor of the overhangs could be due to the corner seams,

for the defect is well-defined along the edges of the overhanging floor. There

are relatively few insulation voids which helps account for the low 6% thermal

defects of the total wall area.

29
Figure 16 Thermal Defects Observed in the Fayetteville Building

16-1

NE corner with one

east face tower

16-3

E end with three

elevator towers

16-2

NW corner with west

wall under overhang

16-4

NW corner above N entrance

with view up to overhang

30
Description of Thermal Defects Observed in the Huron Federal Building

The Federal Building in Huron, SD, is relatively sound with respect to thermal

integrity. The 9% thermal defects in wall area is primarily due to leakage

through seams between floors and thermal bridges at intersections of walls,

floors, and beams, as seen in figure 17-3. There is also an amount of flaring

around and above the windows as shown in figures 17-1 and 17-3. Note how the seams appear to be more defective as they approach the windows, especially as seen in figure 17-3. The brightness in the leftmost side of figure 17-2 is due

to the windows near the front entrance in the background. Figure 17-4 is an interior thermogram of the fourth floor indicating a beam which conducts cold air

in on the right hand side. Figure 17-4 also depicts some shrinkage in the

insulation in the third and fifth sections of the wall, as well as air leakage at

the top and the bottom of the wall where it intersects the floor and ceiling.

31
mrnmmmmmm

Figure 17. Thermal Defects Observed in the Huron Building

17-1

E wall with NE

entrance off to right

17-2

N face with NE

entrance on left

17-3

Close-up of middle

section on E wall as shown in 5-2

17-4

Fourth floor interior

N wall of the E wing

32 !<
Description of Thermal Defects in the Norfolk Federal Building

The thermal anomalies observed in the Federal Building in Norfolk, VA, consisted

of two basic kinds, the leakage that occurred at the wall-to-f loor seams and the

leakage at the exterior panel seams. In figure 18-1, there is a great deal of

heat loss shown at the panel seams in the middle of the east wall. The wall-topost-to-f loor seams are also sources of heat loss as illustrated in figures 18-2

through 18-5. Figure 18-2 shows an interior thermogram of the west wall at the

south end. (The middle window does not have the blind pulled down and is not

reflecting.) Note the vertical darker area in the center of the picture, which

is a beam conducting cold inwards. Figures 18-3, 18-4, and 18-5 show leakage

between the windows and from the panel seams in the solid wall sections below,

which correspond to the horizontal, long, bright white areas across the entire

length of the building. Other thermal defects observed include the floors of the

third floor and second floor overhangs, as evidence of voids in insulation and

leakage at the seams is identified in figures 18-5 and 18-6.

33
Figure 18. Thermal Defects Observed in the Norfolk Building

18-1

Lower wall section

of E wall

i

18-3

W face at the N

end

18-5

Third floor overhang

of the N wall at the

W end

18-2

W wall at S end on

the third floor

18-4

E wall at the

SE corner

18-6

NE overhang of second

floor over garage

34
Description of Thermal Defects Observed in the Pittsfield Federal Building

The thermal integrity of the Federal Building in Pittsfield, MA, can be

characterized by a large number of markedly undefined voids in the insulation.

Many sections have insulation that is distributed unevenly, and there are areas where a whole section of wall is lacking insulation as shown in figure 19-2,

where the top third of the wall next to the front entrance is distinctly warmer.

The large percentage, 18%, of defective wall observed in the Pittsfield Building

is due to these large rectangular voids, but the problems with all types of seams must also be taken into consideration. In figure 19-1 for example, note the

leakage from the seam below the second floor windows and the wall-to-wall seam in

the upper right-hand corner. The posts running through the walls also cause heat

loss as shown in figures 19-4 and 19-6. These two thermograms are characteristic

of those for every wall-to-post seam in the building. At each corner there is an indentation in which there is leakage as illustrated by the thermograms in

figures 19-3 and 19-4, where the exterior and the interior of the NW corner on

the first floor are shown. The dark line in figure 19-4 indicating the

penetration of cold corresponds to the bright white regions in figure 19-3 which

indicate heat loss to the outside. Other defects observed in this building

include the possibility of a damaged pipe inside the north wall as shown in

figure 19-5, where a flaring warm area near the top is detected.
Figure 19. Thermal Defects Observed in the Pittsfield Building

19-1

S end of E wall

(exterior)

19-3

NW corner with N

wall section and

indent (exterior)

19-5

Center of N wall

(exterior)

36

19-2

The front entrance

on E wall (exterior)

19-4

NW corner with W

window and

indent (interior)

19-6

Wall-post seams on E

wall first floor

( interior

)
Description of Thermal Defects in the Springfield Federal Building

The Springfield Federal Building has a relatively low, 7%, rating of wall area

subject to thermal anomalies. The main defect is the post-to-wall joints as seen

in figures 20-1 through 20-6. Note the consistant pattern of the defect in

figures 20-1 and 20-3. An exterior close-up of the post-to-wall seam is shown in

figure 20-2 at the SW corner with an interior view in figure 20-4. The

dimensions of the columns are defined in figures 20-1 and 20-2 by the heat lo68

that occurs at the edges as the column rises up the side of the building. The

interior view shows the cold penetrating to the interior at the sides of the

pillar at a single floor. The heat loss from the joints is also consistently

evident at the corners, where there are small insulation voids above the windows

as well which can be observed in figure 20-3 and 20-5. There is also a great

deal of heat loss from the glass windows on the first floor and from the atrium

which rises up the center of the east face of the building, as shown in figures

20-5 and 20-6.

37
Figure 20. Thermal Defects Observed in the Springfield Building

20-1

SE corner of

the N wing

20-3

SW corner showing seams

at the second and third

floors

20-5

S wall first floor

glass wall with metal

panel, W end

20-2

Close-up of the floor-wallpost seam on the E face of

the N wing

20-4

Interior thermogram of

the wall-post seam

20-6

Atrium rising up

center of E face

38
5. Determination of the Thermal Resistances of the Building Envelope Using

Heat Flow Meters and a Portable Calorimeter

In an attempt to determine the feasibility of directly measuring the thermal

resistance of sections of the building envelope, NBS deployed a micro-computer

based data acquisition system which could monitor the output of heat flow meters,

thermistors for measuring temperature, and the electrical energy used by a portable calorimeter. Two of these systems were used in the project.

The heat flux transducers used for measuring the rate of heat transfer through

the building components included heat flow meters and a portable calorimeter.

The heat flow meter was a 10 cm diameter circular, wafer-type sensor with the hot

and cold junctions of an embedded thermopile attached to its surfaces. The heat

flow meters were attatched with masking tape to the selected locations on the

interior surfaces of the building components including the exterior walls and the

roofs, structural beams and columns, and the floors. The voltage signals produced

by the heat flow meter were proportional to the heat flow through the cicular

disk. The temperatures of the outdoor air and indoor air in the vicinity of the

heat flow meters were measured with thermistors. A portable calorimeter was

designed, constructed, and used for on-site measurement of the rate of heat loss

through the external wall of the selected buildings. The calorimeter consisted

of a five-sided box having dimensions of 124 cm wide by 198 cm high by 20 cm deep

which was fabricated from semi-rigid fiber glass insulation board. The

calorimeter contained an electric heater, which was controlled automatically to

maintain the air temperature inside the calorimeter box equal to that of the

guard room. The heat flow through the metered area was measured by monitoring

the total electrical power consumption of the heater. A watt-hour meter equipped

with an optical electronic device, which generated a pulse for each 1.8 Wh of

electricity consumed by the heater, was installed in the circuit to the heater.

These pulses were totaled by an electronic counter. The outputs from the device

in the modified watt-hour meter, the heat flow meters, and thermistors, were

acquired every two seconds and processed, and the test data were recorded at one hour intervals on a floppy disk by the micro-computer.

Construction details of the typical exterior walls on which heat flow

measurements were made are summarized in table 11. Table 12 presents the thermal

resistance values measured with heat flow meters and the portable calorimeter on

the exterior walls for the test buildings. The measured wall resistance value

was the average of R-values calculated by dividing the average temperature

difference between the inside and outside air present across the building wall,

by the average heat flow rate over a period of 24 hours. The steady-state

thermal resistances of these walls for the test buildings were computed using

the series resistancce method and published data on thermal properties of

building materials. These predicted values are also presented in the table along

with the corresponding measured indoor and outdoor air temperatures. The

calibration of heat flow meters employed a standard guarded hot plate apparatus.

The sensitivity of individual heat flow meters was determined by inserting them

between the warm and cold plates maintained at constant temperatures and

subjecting each meter to a unifrom heat flux at the mean temperatures experienced

during the tests. Also shown in the table are the significantly high wall

resistance measured by the calorimeter for the building in Columbia, SC, which

may have resulted from additional heat laterally conducting into the measuring

area from a nearby hot air duct.

39
Table 11. Construction of External Walls of Test Buildings

Building Location Wall Description

Ann Arbor

,

Michigan

1.3 cm (0.5 in.) Quarry tile, 2.5 cm (1 in.) metal lath and

motar bed, 25.4 cm (10 in.) concrete masonary unit, 3.8 cm (1.5 in.) semi-rigid glass fiber insulation board and 1.3 cm

(0.5 in.) acoustic wall panel

Columbia

,

S. Carolina

5.1 cm (2 in.) granite siding, 22.9 cm (9 in.) concrete, 5.1 cm (2 in.) glass fiber blanket insulation, and 1.6 cm (0.625

in.) gypsum wallboard

Springfield,

Massachusetts

14.0 cm (5.5 in.) precast concrete panel, 6.4 cm (2.5 in.)

semi-rigid glass fiber insulation board, and 1.3 cm (0.5 in.)

gypsum wallboard on 9.2 cm (3.625 in.) metal studs

Huron,

S. Dakota

10.2 cm (4 in.) face brick, 15.2 cm (6 in.) light-weight

concrete masonary unit, 7.6 cm (3 in.) semi-rigid glass fiber

insulation board, and 1.6 cm (0.625 in.) gypsum wallboard

Norfolk,

Virginia

10.2 cm (4 in.) face brick, 1.9 cm (0.75 in.) air space, 1.3 cm (0.5 in.) gypsum board sheathing, 10.2 cm (4 in.) glass

fiber blanket insulation, and 1.3 cm (0.5 in.) gypsum

wallboard

Pittsf ield,

Massachusetts

10.2 cm (4 in.) face brick, 5.1 cm (2 in.) semi- rigid glass

fiber insulation board, and 10.2 cm (4 in.) brick

Anchorage

,

Alaska

12.7 cm (5 in.) precast concrete panel, 7.6 cm (3 in.) semirigid glass fiber insulation board, 10.2 cm (4 in.) glass

fiber batt insulation, and 1.6 cm (0.625 in.) foil backed

gypsum wallboard on 6.4 cm (2.5 in.) metal studs

Fayetteville,

Arkansas

10.2 cm (4 in.) face brick and 30.5 cm (12 in.) concrete

block

40
Table 12. Comparsion of Wall Thermal Resistances Measured With a Portable

Calorimeter and Heat Flow Meters to Corresponding Predicted Values

Building Air Temperature Wall Thermal Resistance

Location (°C) (m2-°C/W)

Measured Values

Hot

Side

Cold

Side Calor imeter

Heat Flow

Meter

Predicted

Value*

Ann Arbor,

Michigan 20.1 4.1 1.95 2.03 1.87

Columbia,

S. Carolina 21.3 8.8 2.66 1.90 1.98

Springfield,

Massachusetts 20.8 5.5 1.20 2.22 2.29

Huron,

S. Dakota 19.4 3.3 2.11 3.60 2.97

Norfolk,

Virginia 25.1 9.1 — 1.46 2.76

Pittsfield,

Massachusetts 25.4 3.7 — 1.81 1.80

Anchorage,

Alaska 23.4 10.3 — 6.88 5.27

Fayetteville,

Arkansas — — — — 0.56

* Note: These values

inside surface and

include

0.70 m^

> air films with thermal resistances 0.

-°C/W at the outside surface. This is

12 m

2-°C/W at

based on an

air velocity of 0.3 m/s across the hot, and 0.2 m/s for the cold side surfaces,

respectively.

41
6. Conclusions

This interim report has presented some preliminary findings of the building

diagnostic tests of the eight GSA federal buildings. The air infiltration and

pressurization measurements show that these buildings are not excessively leaky.

In fact, they are tighter than most U.S. homes. The infrared inspections have

located sites of air leakage and insulation defects in all the buildings. The

percentage of wall area exhibiting thermal defects ranges from about 10 to 20% in

the buildings. The U-value measurements show varying correlation with the

calculated values. It is not clear whether any disagreement between these

measurements and predictions arise from measurement techiques or predictive

methods. Both estimates are based on assumptions of one-dimensional heat flow

and this may not always be a good approximation. Further reports on this project

will contain additional analysis of the infrared inspections and U-value

measurements. Also, additional study of the air infiltration data, particularly

weather dependence of infiltration, will be presented.

42
7. Acknowledgements

The authors would like to thank David Eakins and Erma Striner of GSA for their

continued support, assistance and encouragement. The technical contributions of

Douglas Pruitt and Steve Schweinfur th's assistance in data analysis must al6o be

noted.

43
REFERENCES

1. Grot, R.A., Burch. D.M. , Silberstein, S., and Galowin, L.S., "Measurement

Methods for Evaluation of Thermal Integrity of Building Envelopes," NBSIR

82-2065, 1982.

2. Grot, R.A. , Hunt, C.M., and Harrje, D.T., "Automated Air Infiltration

Measurement in Large Buildings," Proceedings of First Air Infiltration Centre

Conference, Windsor, October, 1980.

44
NBS-114A (rev. 2 «eo) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

PUBLICATION OR

REPORT NO.

NBSIR 83-2768

2. Performing Organ. Report NoJ 3.

4. TITLE AND SUBTITLE

Publication Date

September 1983

Interim Report on NBS Thermal Integrity Diagnostic Tests on Eight

GSA Federal Office Buildings

5. AUTHOR(S)

6

9

Richard A. Grot, Yui-May Chang, Andrew K. Persily, Jin B. Fang

. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions) 7. Contract/Grant No. Interagency Agreement

national bureau of standards PBS-80-1

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Public Building Service

General Services Administration

Washington, D.C. 20405

10. SUPPLEMENTARY NOTES

I I 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 summarizes preliminary results of diagnostic tests to evaluate the

thermal integrity of eight Federal office buildings located throughout the

country. The test results include tracer gas measurements of air infiltration

rates, pressurization tests of the air tightness of the building shell, and

inspections of the envelope employing infrared thermography. In addition, the

thermal U-values of exterior walls were measured with both heat flow meters and

a portable calorimeter box. The data collected on these buildings are still

undergoing analysis and therefore are to be considered preliminary.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names ; and separate key words by semicolons)

air infiltration; building diagnostics; building thermal integrity; fan

pressurization; field measurements; thermographic inspections; tracer gas technique;

U-value tests

13. AVAILABILITY 14. NO. OF

PRINTED PAGES m Unl imited

| | For Official Distribution. Do Not Release to NTIS 50

1 Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 15. Price

G3 Order From National Technical Information Service (NTIS), Springfield, VA. 22161 $8.50

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