-------
EPA 600/2-81-073
April 1981
EVALUATION OF THE WALKTHROUGH SURVEY
METHOD FOR DETECTION OF
VOLATILE ORGANIC COMPOUND LEAKS
By
Robert C. Weber and Kenneth Mims
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
Industrial Environmental Research Laboratory
Office of Research and Development
U. S. Environmental Protection Agency
Cincinnati, Ohio 45268
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/2-81-073
3. RECIPIENT'S ACCESSION NO.
ran 19938 2
4. TITLE AND SUBTITLE
Evaluation of the Walkthrough Survey Method for
Detection of Volatile Organic Compound Leaks
S. REPORT DATE
April 1981 (issue date)
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Robert C. Weber and Kenneth Mims
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. EPA
Industrial Environmental Research Laboratory
Industrial Pollution Control Division
26 W. St. Clair Street Cincinnati, OH 45268
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
N/A (inhouse)
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. EPA
Industrial Environmental Research Laboratory
26 W. St. Clair Street
Cincinnati, OH 4526S
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
1S. SUPPLEMENTARY NOT1ES
16. ABS1 R ACT , _ _ . _ _ _ . _ • « _ . < ••• . .
During 1978 and 1979, the Emission Standards and Engineering Division of EPA s
Office of Air Quality Planning and Standards conducted a fugitive volatile organic
compound (VOC) emission sampling program in organic chemical manufacturing plants
and petroleum refineries. As a part of their sampling program, several "walkthrough
surveys," also called "unit area surveys," were conducted. The assistance of EPA's
Industrial Environmental Research Laboratory-Cincinnati was requested in the analysis
of the walkthrough survey data.
Fourteen walkthrough surveys were analyzed, from four plants. The analysis
reported here focuses on the variability and reproducibility of the survey method.
One indicator of variability which was studied was the coefficient of variation (CV).
The CV's ranged from 55% to 408%, for each pair of walkthrough surveys. 7urther,
the linear correlation coefficients for each set of surveys ranged from 0.046 to
0.98. No attempt was made to evaluate the sources of the variability.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IDbNTIFIE RS/OPEN ENDED TERMS
c. COSATI l icld/Group
volatile organic compounds (VOC)
fugitive emissions
statistical analysis
chemical emissions
leak detection
*
VOC (volatile organic
compounds)
organic vapor
analyzer (OVA)
engineering
statistics
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES " "
20. SECURITY CLASS /Thispege)
unclassified
22. PRICE
EPA Form 2220-1 (R«». 4-77) previous edition is obsolete '
-------
DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U.S. Environmental Protection Age,icy, and approved for publica-
tion. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
-------
FOREWORD
When energy and material resources are extracted, processed, converted
and used, the related pollutional impacts on our environment and even on our
health often require that new and increasingly more efficient pollution con-
trol methods be used. The Industrial Environmental Research Laboratory -
Cincinnati (IERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
This report, "Evaluation of the Walkthrough Survey Method for Detection
of Volatile Organic Compound Leaks," prpsents an evaluation of data collected
by EPA's Emission Standards and Engineering Division, Office of Air Quality
Planning and Standards, on a field survey technique for the detection of
leaks of volatile organic compounds (VOC) from process equipment. The analy-
ysis reported here focuses on the variability and reproducibility of the
survey method.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
-------
ABSTRACT
During 1978 and 1979, the Emission Standards and Engineering Division
of EPA's Office of Air Quality Planning and Standards conducted a fugitive
volatile organic compound (VOC) emission sampling program in organic chemical
manufacturing plants and petroleum refineries. As a part of their sampling
program, several "walkthrough surveys," also.called "unit area surveys,"
were conducted. The assistance of EPA's Industrial Environmental Research
Laboratory-Cincinnati was requested in the analysis of the walkthrough survey
data
Fourteen walkthrough surveys were analyzed, from four plants. The
analysis reported here focuses on the variability and reproducibility of the
survey method. One indicator of variability which was studied was the
coefficient of variation (CV). The CV's ranged from 55% to 408%, for each
pair of walkthrough surveys. Further, the linear correlat ion coefficients
for each set of surveys ranged from 0.046 to 0.98. No attempt was made to
evaluate the sources of the variability.
iv
-------
CONTENTS
Foreword iii
Introduction 1
Walkthrough Survey Method 2
Data Analysis Methods and Results 3
Appendix 6
v
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SECTION 1
INTRODUCTION
During 1978 and 1979, the Emission Standards and Engineering Division
of EPA's Office of Air Quality Planning and Standards conducted a fugitive
volatile organic compound (VOC) emission sampling program in organic chemical
manufacturing plants and petroleum refineries. The data were used in the
development of background information documents for regulations to control
VOC emissions resulting from leaks in process equipment. As a part of this
sampling program, several "walkthrough surveys," also called "unit area
surveys," were conducted. A unit area survey involves measuring the ambient
VOC concentration within approximately 1 meter of all ground level equipment
within a processing area. These measurements are performed with a portable
VOC detection instrument utilizing a strip chart recorder. An elevated
reading on the strip chart is assumed to be indicative of a leak. Each
individual piece of equipment located in the ar«a where the elevated VOC
concentration was found is then checked to determine the sources of the VOC
emissions.
The purpose of the walkthrough surveys conducted by EPA was to determine
if this approach represents a viable technique for the detection of leaks
within a regulatory context. The assistance of EPA's Industrial Environmen-
tal Research Laboratory in Cincinnati u*as requested in the analysis of the
walkthrough survey data. The purpose of this report is to document the
techniques of data analysis and to present the results. Fourteen walkthrough
surveys from four plants were analyzed. The analysis reported here focuses
on the variability and reproducibility of repeated surveys and does not
attempt to correlate increased ambient VOC concentrations with specifically
located VOC sources.
1
-------
SECTION 2
WALKTHROUGH SURVEY METHOD
The walkthrough surveys were conducted at four plants: two chloromethane
units, one ethylene unit, and a benzene-toluene-xylene (BTX) unit in one
petroleum refinery. The instrument used i.n all cases was the Century Systems
Corporation Organic Vapor Analyzer (OVA), Model 108, which was equipped with
a strip chart recorder. The instrument measures organic vapor concentrations
in ppmv. For each unit or section of a unit, a walkthrough path was develop-
ed. This path was intended to'pass within a meter of major pieces of equip-
ment at ground level, e.g., pump rows, compressors.
Copies of the strip charts from the OVA recorder are in the Appendix
(Figures 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25 and 27). The letters
(A, B, C, etc.) on the charts designate specified locations within the process
unit. Two surveys were conducted sequentially, usually within a few minutes
of each other. In the Appendix, the strip charts for the two surveys are
placed side by side to facilitate comparison. The beginning and ending
times were also recorded.
2
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SECTION 3
DATA ANALYSIS METHODS AND RESULTS
As stated before, the data analysis focused on the variability and repro-
ducisility of the measurement technique. That is, the data were analyzed to
determine if an increased VOC concentration was found at the same location
on two surveys. Therefore, both the coefficient o£ variation (CV) and the
linear correlation coefficients (R) were evaluated, for each pair of walk-
through surveys (i.e., the sequential surveys for each path). First, however,
a technique was developed to facilitate direct comparison of the two chart
recordings.
The first step was to trace a continuous curve through the discontinuous
marks made on the strip chart by the OVA recorder. The "smooth" curve on
the strip chart was then divided into cells which contained the location
designations A, B, C, etc. This was done by finding the midpoints of the
interval between two locations, e.g., B to C, and C to D. These two mid-
points, then, form the cell boundary for che cell which contains "C." These
are shown in the charts as long, darker horizontal lines. Once the cells
were identified, the maximum value for each cell was read directly from the
chart. Although the actual units are unimportant for the analysis reported
here, the instrument read-out is in ppmv. It should be noted that the charts
have a logarithmic scale.
In the Appendix, the chart on the left has been designated as Survey A
and the chart on the right as Survey B. The tables in the Appendix (Tables 2
through 15) include the survey location codes, the maximum values in each
cell for Survey A and Survey B, and the absolute value of the difference
between the corresponding maximum values for each cell, designated as |(A-B)|.
The absolute value of the difference was used since only the magnitude of
the difference is important, and not the fact that values from Survey A are
higher (or lower) than Survey B.
The following statistics were calculated for each pair of walkthrough
surveys:
n
x = mean difference = Z1(A-B)I
n
s = standard deviation of the mean difference
CV = coefficient of variation ¦ s x 100
a
3
-------
R = linear correlation coefficient (between the Survey A and
Survey B values)
The results are summarized in Table 1.
The coefficient of variation provides one way to evaluate the variability
of data sets which have widely varying means. Because the means observed
were widely different, a simple analysis of the standard deviations for each
walkthrough survey would not yield meaningful results. To reduce the effect
of the differing means, the coefficient of variation was selected.
The CV's ranged from 85% to 408%. Further, there does not appear to be
any trend relative to plant or type of production facility.
The sample linear correlation coefficients ranged from 0.046 to 0.98.
A value near 1 indicates a strong linear relationship in which the value
from Survey B increases when the value from Survey A increases. A value of
R close to zero results from data that display a strictly random effect,
which implies little or no relationship. However, since R is a measure of
the linear relationship, a value of R u ir zero really implies a lack of
linearity and not necessarily a lack of association. Therefore, the data
were plotted to observe the suitability of the linearity assumption. These
are Figures 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 and 28 in the
Appendix.
Based on the results reported h-:re, it appears that the walkthrough
survey technique is highly variable and is not reproducible in many cases,
even when repeated within minutes. In several instances, there is essentially
no correlation between the pair of surveys, as indicated both by the linear
correlation coefficients (R) and by the plots of the data. Thus, there is no
indication that the walkthrough survey method can be used as the basis of a
leak detection program for regulatory purposes. To be used for such purposes
a maximum local ambient VOC concentration which triggers remedial action woulo
have to be established. This analysis shows that on repeated surveys a local
concentration is usually not repeated on two passes by the same location, nor
are the concentrations linearly proportional.
4
-------
TABLE I
WALKTHROUGH SURVEY SUMMARY
Plant
CV
1) Dow Chemical, Plaquemine, La. 9
(grid #1)
2) Dow Chemical, Plaquemine, La. 25
(grid #2)
3) Dow Chemical, Plaquemine, La. 25
(grid #2, rpt)
4) Dow Chemical, Plaquemine, La. 26
(grid #3)
5) Dow Chemical, Plaquemine, La. 38
(grid #4)
6) Dow Chemical, Plaquemine, La. 26
(grid #5)
7) Dow Chemical, Plaquemine, La. 11
(grid #6)
0.89 0.78 88% 0.77
4.04 8.82 2182 0.51
0.96 1.43 149% 0.98
0.87 0.87 100% 0.37
9.57 39.01 408% 0.65
14.77 31.11 211% 0.046
1.91 1.04 55% 0.11
8) Stauffer, Louisville, Ky.
(Walkthrough Survey)
9) Union Carbide, Torrance, Ca.
(Storage Area #2)
32 160.66 373.80 233% 0.89
81.22 79.63 98% 0.14
10) Union Carbide, Torrance, Ca. 27
(Furnace Unit #4)
12.85 18.12 141% 0.58
11) Union Carbide, Torrance, Ca.
(Separation Area)
12) Union Carbide, Torrance, Ca.
(Olefins Separation Plant)
13) Union Carbide, Torrance, Ca.
(Compressor Bldg, Area #3)
32 114.50 290.75 254% 0.84
32 18&.75 179.63 95% 0.70
27 247.11 431.65 175% 0.80
14) Sun Oil, Toledo, Oh. 51
(Unit Walkthrough, BTX)
n = number of da^a points
x = mean difference
s ¦ standard deviation
CV = coefficient of variation
R ¦ linear correlation coefficient
2.27 7.38 325% 0.25
-------
APPENDIX
-------
FIGURE 1
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 1)
V vvyX • ^
Reproduced from
best available copy.
7
-------
TABLE 2
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough Grid #1
absolute value
maximum value (ppm) of the difference
Location
Survey A
Survey B
1 (A-i
A
10
9
1
B
9
10
1
C
9
9
0
D
8
9
1
E
8
8
0
F
7
7
0
G
6
5
1
H
7
5
2
I
10
8
2
8
-------
.i- Maxiimutt Zonae
j (g(>w ]heftic >1.: P-l Hjufoni ie. :rLAl €rid
rvijv' ift: v-r. i urvey B)
-------
FIGURE 3
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 2)
cP^
-
m
Reproduced from
best available copy.
: y—
£ - •
—¦
10
-------
TABLE 3
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough Grid #2
maximum value
(ppm)
absolute value
of the difference
Locat ion
Survey A
Survey B
1(A-B)I
A
8
7
1
B
20
20
0
C
20
20
0
D
12
10
2
E
12
5
7
D
10
15
5
C
20
15
5
F
60
15
45
G
7
10
3
H
12
to
2
I
6
15
9
J
7
6
1
K
8 .
6
2
L
8
8
0
K
6
8
2
J
7
5
2
I
8
7
1
M
7
7
0
N
6
5
1
0
7
10
3
P
7
10
3
Q
6
10
4
R
5
6
1
S
8
6
2
A
8
8
0
11
-------
-------
FIGURE 5
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 2 - repeat)
13
-------
TABLE 4
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough #2 (Repeat)
maximum value (ppm)
Grid Location
A
B
C
D
E
D
C
F
G
H
I
J
K
L
K
J
I
M
N
O
P
Q
R
S
A
Survey A
5
40
20
7
4
4
4
4
6
4
4
4
4
5
4
4
4
4
4
10
8
5
4
6
6
Survey B
5
40
20
10
4
8
9
5
4
4
4
4
10
9
5
6
9
6
absolute value
of the difference
l(A-B)|
0
0
0
3
0
4
5
1
2
0
0
0
0
0
1
0
1
1
0
0
1
o
2
3
0
14
-------
15
-------
FIGURE 7
Scrip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 3)
-
—
V
#, ,
—
/ S}_
' ^
i_ n
^
_ v
V—; 11 .
•
»v. * .
i
• .
—— ^ - --- -
•
1—
"X c. ~
_ J—> it-
J \
3 — 'S
- -v ¦
i •—
t —
- 1- &
—-
— V
...j \
— v\
— t -
v
—
— V,
-
{.x:: .
16
-------
TABLE 5
Dow Chemical company
Plaquemine, Louisiana
Walkthrough Grid #3
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B I (A-B) I
A
6
5
1
B
7
6
1
C
6
5
1
D
7
5
2
E
6
5.5
0.5
F
6
6
0
C
7
8
1
H
8
9
1
I
8
6
2
J
6
6
0
K
6
6
0
L
6
5.5
0.5
M
6
6
0
.N
9
5
4
0
7
5.5
1.5
P
5
5
0
Q
6
5
1
R
6
5
1
S
6
5
1
T
6
5
1
U
6
5
1
E
5
6
1
D
6
6
0
C
6
5.5
0.5
B
6
5.5
0.5
A
5
5
0
17
-------
w
:»
as
s>
to
-------
FIGURE 9
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No 4)
19
-------
FIGURE 9 (Continued)
Reproduced from
best available CQPV*_j|y
7S
*t77F"
W
-------
TABLE 6
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough Grid #4
absolute value
maximum value (ppm) of the difference
Grid Locat ion Survey A Survey B I (A-B) |
A 5 6 1
B 300 60 240
C 17 30 13
D 5 9 4
E 6 6 0
F 8 5 3
G 5 5 0
F 6 5 1
E 6 6 0
D 8 7 1
C 6 7 1
B 5 6 1
FF 5 5 0
H 9 25 16
I 7.5 10 2.5
J 7 6 1
K 6 8 2
L 7 6 1
M 5 6 1
N 5 7 2
0 5 6 1
P 9 8 1
Q 13 20 7
R 30 70 40
S 5 5 0
T 5 9 4
U 7 5 2
21
-------
TABLE 6 (Continued)
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B 1 (A-B) I _
V 7 6 1
W 7 6 1
X 6 6 0
Y 6 5 1
Z 6 7 1
AA 5 10 5
BB 5 9 4
CC 5 6 1
DD 6 8 2
EE 8 9 1
A 7 8 I
22
-------
-------
FIGURE 11
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 5)
Reproduced from
best available copy.
24
-------
FIGURE 11 (Continued)
25
-------
TABLE 7
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough Grid #5
absolute value
maximum value (ppm) of the difference
Location
Survey A
Survey B
IU-:
A
6
15
9
B
90
15
75
C
30
40
10
D
7
5
2
E
7
10
3
F
5
10
5
G
7
5
2
H
20
5
15
I
50
6
44
J
30
5
25
K
150
5
145
L
10
5
5
M
6
6
0
N
10
6
4
0
7
10
3
P
7
10
3
Q
12
5
7
R
10
8
2
S
8
6
2
T
9
7
2
U
7
8
1
V
25
30
5
w
10
15
5
X
10
7
3
Y
15
10
5
A
10
8
2
26
-------
»
i
*-~r~
S--4--
-------
FIGURE 13
Strip Chart Recording
(DOW Chemical, Plaquemine, LA, Grid No. 6)
28
-------
TABLE 8
Dow Chemical Company
Plaquemine, Louisiana
Walkthrough Grid #6
absolute value
maximum value (ppm) of the difference
Location
Survey A
Survey B
1(A-B)1
A
6
8
2
B
5
6
1
C
5
6
I
D
5
5
0
E
5
6
I
F
8
5
3
C
9
6
3
H
10
7
3
I
10
7
3
J
6
8
2
A
5
7
2
29
-------
10
-------
FIGURE 15
Strip Chart Recording
(Stauffer Chemical, Louisville, KY)
® ; ' j
/* i
31
-------
FIGURE 15 (Continued)
-------
TABLE 9
Stauffer Chemical Company
Louisville, Kentucky
Walkthrough Survey
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B | (A-B) I
A 2.5 2 .50
B 18 18 0
C 10 12 2
D 3 40 37
E 150 2000 1850
F 60 15 A5
G 1.5 6 4.5
H 8 15 7
I 3 12 9
J 12 1.5 10.5
K 20 1.5 18.5
L 30 6 24
M 30 50 20
N 25 7 18
0 10 3 7
P 4 4 0
Q 1000 600 400
R 800 300 500
S 50 10 40
T 90 20 70
U 60 15 45
V 25 6 19
W 80 30 50
X 120 60 60
Y 5000 4000 1000
Z 600 800 200
33
-------
TABLE 9 (Continued)
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B | (A-B) |
AA 500 1000 500
BB 300 300 0
CC 80 30 50
J 100 4 96
K 60 6 54
Stop 4 8 4
34
-------
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35
a;:
iiliii
1 ¦
-------
FIGURE 17
Strip Chart Recording
(Union Carbide, Torrance, CA, Storage)
36
-------
TABLE 10
Union Carbide
Torrance, California
Storage Area Walkthrough (Area #2)
absolute value
_ maximum value (ppm) of the difference
Grid Location Survey A Survey B I (A-B) I
A 9 10 I
B 15 15 0
C 80 30 50
D 200 100 100
E 50 300 250
F 60 200 140
G 150 200 50
H 60 30 30
I 150 40 110
37
-------
Maxumra
m
f.-
ii
CURE (1S T:
~T:t~
ui —: —
Cooceotration KSujrvey i(' vs. Survey |B)
W^W
:r r"i~~
": i
-J.
rrrr—*~. r—! ] • j "~t
i^Ta^»ce, Cfa„Sto|?g«).
-------
FIGURE 19
Strip Chart Recording
(Union Carbide, Torrance, CA, Furnace Unit)
I-- 11'lt
\JCC
39
-------
FIGURE 19 (Continued)
AO
-------
TABLE 11
Union Carbide
Torrance, California
Furnace Unit (Area #4)
maximum value
(pp«)
absolute value
of the difference
Location
Survey A
Survey B
1(A-B)1
A
8
9
1
B
15
15
0
C
15
15
0
0
50
80
30
E
80
50
JO
F
30
30
0
G
40
70
30
H
60
40
20
I
40
20
20
J
25
20
5
K
30
30
0
L
15
30
15
M
15
15
0
N
8
20
12
0
20
20
0
P
15
15
0
Q
17
30
13
R
30
50
20
S
40
90
50
T
30
50
20
U
15
90
75
V
8
9
I
w
9
9
0
X
7
9
2
Y
8
10
2
Z
9
10
I
A
10
10
0
41
-------
|Cortc«|t rat ion ^SuyveV A vei S< rv«y 1
iii :- 1 ' dOaioft ;Ca*bi4e. To^raiice^ GA. lurftac^ Urtit) j_
¦:-¦¦ :• I ::: 1...T : I . ; : J 5 " • :
! :
• r •
; * ; ' i
WfM
i
i
-i-
I :
: 1...
1~.
: I :¦ ;
8-
-8-
^ir4-r,4-i-i
i
I '
J---
r~ 1—
I • :
-r-t-
m
...j :
I !
:
t
' I ' i
u
i—1—{¦
t-t
u
tt-h-
:!:¦•:
H T-f-r
fi
i
c.
§ «
_ «
s" ' I
* : I
:! 1
m
*
cc
»
IA
.X
j
r:n.i
...
T"
i-
P i.
I - * : I'' !
i; r:: 1
r
lltiMMa Cof»peokr«l:ior { tpmirj
¦ -i
TT-:r-
:tr.
::::} ¦
llElilihilf
::;: I:.
: J.
*
¦T"U'|r?.Tt f n
t:
• »*
Liiiii
42
---t ••
. !.
rt i-
.1
_—L
. I
_0_
-------
FIGURE 21
Strip Chart Recording
(Union Carbide, Torrance, CA, Separation Area)
' in hi
<
C/ ii
__ i
L . O. C-
e*<£. ..
(V,.j
r„
A
-i
(
^ T5
1 ~ l
(
< — c_
% /-s ¦
m s.
(
3* _ »s
V n
43
-------
FIGURE 21 (Continued)
44
-------
FIGURE 21 (Continued)
45
-------
TABLE 12
Union Carbide
Torrance, California
Separation Area
absolute value
maximum value (ppm) of the d i fference
Locat ion
Survey A
Survey B
l(A-B)
A
15
4
11
B
17
4
13
C
15
5
10
D
15
15
0
E
10
40
30
F
30
10
20
G
13
15
2
H
13
15
2
I
20
50
30
J
9
15
6
K
40
100
60
L
400
150
250
M
60
40
20
N
30
10
20
0
150
200
50
P
3000
1500
1500
Q
1500
2000
500
R
15
6
9
S
30
6
24
T
50
7
43
U
20
17
3
V
30
15
15
W
80
30
50
X
8
7
1
Y
200
20
180
Z
100
40
60
-------
TABLE 12 (Continued)
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B I (A-B) I
AA 150 150 0
BB 150 800 650
CC tO 60 0
DD 30 70 40
EE 200 150 50
A 5 20 15
47
-------
Mfcclwimj Gonee ttrtit i< >n CSu ry$y A
1
(union Qarbiidq, fornaae'e, jCA,i Sc
r~
t
:: :
¦ :r ¦
¦ i-.
V3i.;;-Survey
p«Bfltion Are
a) '
1
1 .. ,
r r
• t
T"
f"
-4~-
. 1 !
i ..
... *...»—.
4---U
a-;.
:i
§;
-iA-..
n
-O—L
""i. :
S T
o
o
(N .
Q:"
: * *
-j—i- to,
< • ' V
v ta
g
:i a *
j: : ;
cvJ :
o
o
i£U
.-*¦
. *....
m
:t:r.
a:-:
O:
o
: 1it
:::n—ti
I
ft
fri;:
«n:
trr
rr~
f •»-»»»JC «t—
::.«rfi:
in
.. ir .
f
•4—<>--
::::::
Con
:s:u
:en|t ra)t ioiT:C j>pmy ?
ni k :*1
iii
litii
lM;
48
1
-------
FIGURE 23
Strip Chart Recording
(Union Carbide, Torrance, CA, Olefins Separation)
49
-------
FIGURE 23 (Continued)
50
-------
FIGURE 23 (Continued)
51
-------
TABLE 13
Union Carbide
Torrance, California
Olefins Separation Plant (Area #1)
absolute value
maximum value (ppm) of the difference
Grid Location Survey A Survey B I (A-B) I
A
20
90
70
B
200
300
100
C
250
150
100
D
100
100
0
E
60
100
40
F
200
150
50
G
300
500
200
H
200
150
50
I
400
150
250
J
100
150
50
K
400
200
200
L
300
500
200
M
500
200
300
N
600
100
500
0
60
40
20
P
300
600
300
Q
200
150
50
R
400
200
200
S
80
300
220
T
60
30
30
U
300
100
200
V
900
100
800
w
1500
2000
500
X
125
70
55
Y
1000
500
500
Z
40
400
360
52
-------
TABLE 13 (Continued)
absolute value
maximal value (ppw) of the difference
Grid Location Survey A Survey B I (A-B) I
AA 500 400 100
BB 600 400 200
CC 300 400 100
DO 200 100 100
EE 80 175 95
AA 300 400 100
53
-------
rtrr
• * * t- -- -
TTtrfr
773-rm
tfexunua
IHH;
HT3H:
:i:::|?ICURK
Conic t$at rat aon KStjrvey a| vsr^i
•{UniiDtt Carbide,! Torrance, OA, Olefins £
uiruey B) :
:T:-"r
:: ;t:.
i
i ... 1
m
• T • • ;
i r - m
: ..t
—_!
dion)
-------
FIGURE 25
Scrip Chart Recording
(Union Carbide, Torrance, CA, compressor building)
55
-------
FIGURE 25 (Continued)
Reproduced trom
bctt available copy.
~ ™- - ~T
» • • ——* - > r~
J.
~rz—
14,.'.
1 x .&¦ !
¦ i t_—1 —~ ;
56
-------
TABLB 14
Union Carbide
Torrance, California
Compressor Building (Area #3)
maximum value (ppc)
absolute value
of Che difference
Location
Survey A
Survey B
I (ah
A
50
200
150
B
400
600
200
C
600
500
100
D
600
500
100
E
150
400
250
F
800
1000
200
G
600
500
300
H
700
500
200
I
2000
1000
1000
J
900
450
450
D
300
200
100
A
3000
900
2100
I
80
70
10
H
15
35
20
N
15
30
15
0
10
15
5
P
30
30
0
Q
70
30
40
R
200
40
160
S
300
40
260
T
800
500
300
H
300
300
0
G
200
300
100
U
1000
400
600
V
50
40
10
W
30
30
0
X
17
15
2
57
-------
-------
FIGURE 27
Strip Chart Recording
(Sun Oil, Toledo, OH, BTX unit)
59
-------
FIGURE 27 (Continued)
60
-------
TABLE IS
Sun Oil Company
Toledo, Ohio
BTX Unit
maximum value
(ppm)
absolute value
of the difference
Location
Survey A
Survey B
l(A-B)I
A
5
5
0
B
7
6
1
C
5
6
1
D
6
6
0
E
6
6
0
F
8
6
2
G
5
5
0
H
5
5
0
I
6
5
1
J
6
5
1
K
5
6
1
L
7
6
1
M
15
8
7
N
15
15
0
0
7
7
0
P
8
8
0
Q
5
7
2
R
5
5
0
S
5
6
1
T
5
6
1
U
6
10
4
V
15
10
5
w
5
5
0
X
5
6
1
Y
7
5
2
Z
5
4
1
61
-------
TABLE 15 (Cont inued)
Grid Location
Survey
a2
5
b2
5
C2
6
D 2
5
e2
6
f2
6
g2
7
h2
7
12
6
^2
8
k2
5
5
m2
6
n2
6
o2
7
P2
6
Q2
9
r2
60
s2
6
t2
7
U2
6
v2
5
w2
5
X2
5
Z2
4
absolute value
maximum value (ppm) of the difference
Survey B l.(A-B) I
5 0
4 1
4 2
5 0
5 1
5 1
5 2
5 2
6 0
5 3
5 0
5 0
5 1
5 I
6 1
6 0
8 1
7 53
7 1
9 2
8 2
6 1
8 3
8 3
7 3
62
-------
63
-------