VOLUMETRIC LEAK DETECTION IN LARGE
UNDERGROUND STORAGE TANKS
VOLUME I
by
James W. Starr, Richard F. Wise, arid Joseph W. Maresca, Jr.
Vista Research, inc.
Mountain View, California 94042
Contract No. 68-03-3409
Project Officer
Robert W. Hillger
Superfund Technology Demonstration Division
Risk Reduction Engineering Laboratory
Edison, New Jersey 08837
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268

-------
DISCLAIMER
This material has been funded wholly or in part by the United States Environmental
Protection Agency under Contract 68-03-3409 to CDM Federal Programs Corporation. It has
been subject to the Agency's review and it has been approved for publication as an EPA
document. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
HZ
ii

-------
FOREWORD
Today's rapidly developing and changing technologies and industrial products frequently
carry with them the increased generation of materials that, if improperly dealt with, can threaten
both public health and the environment. The U. S. Environmental Protection Agency is charged
by Congress with protecting the nation's land, air, and water resources. Under a mandate of
national environmental laws, the agency strives to formulate and implement actions leading to a
compatible balance between human activities and the ability of natural systems to support and
nurture life. These laws direct the EPA to perform research to define our environmental
problems, measure the impacts, and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning, implementing,
and managing research, development, and demonstration programs to provide an authoritative,
defensible engineering basis in support of the policies, programs, and regulations of the EPA
with respect to drinking water, wastewater, pesticides, toxic substances, solid and hazardous
wastes, and Superfund-related activities. This publication is one of the products of that research
and provides a vital communication link between the researcher and the user community.
This document presents the results of experiments conducted on 190,000-L (50,000-gaI)
underground storage tanks (USTs) to determine how to test large tanks for leaks with volumetric
leak detection systems. The work reported in this document has applications to the UST release
detection technical standards in CFR 280 Subpart D.
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
iii
83

-------
ABSTRACT
The performance standards established by the EPA underground storage tank (UST)
regulation (40 CFR Parts 280 and 281) for volumetric leak detection systems, which include tank
tightness testing systems and automatic tank gauging systems (ATGS), were based upon
experimental research in tanks having capacities of 30,000 L (8,000 gal) and 38,000 L
(10,000 gal). However, the regulation requires the testing of tanks as large as 190,000 L
(50,000 gal). The performance of volumetric systems in detecting leaks from large tanks is not
well known, and there exist very little data from which an assessment can be made. As a
consequence, there is not enough information to help owners and operators select systems that
will be in compliance with the regulations when it comes to testing large tanks, i.e., those
between 57,000 and 190,000 L (15,000 and 50,000 gal).
This report addresses three important questions about testing the larger underground
storage tanks for leaks. First, can the EPA regulatory standards be met when volumetric
methods are used to test tanks up to 190,000 L (50,000 gal) in capacity? Second, what is the
precision required of the temperature and level sensors and what is the minimum duration of the
data collection period in order for a volumetric system to accurately test larger tanks, particularly
those that are partially filled? Third, what are the important features of a volumetric system that
meets or exceeds the regulatory performance standards?
These questions were addressed in a set of experiments conducted on two partially filled
190,000-L (50,000-gal) underground storage tanks at Griffiss Air Force Base in upstate New
York during late August 1990. The experiments suggested that the time required for the
temperature inhomogeneities within the product and for the structural deformation of the tank
system to become negligible after any large addition or removal of product and after topping is
approximately the same as observed in 30,000-L (8,000-gal tanks); in tests on the 190,000-L
(50,000-gal) tanks, however, the temperature inhomogeneities were greater than in tests on
30,000-L (8,000-gal) tanks. Thus, a system's performance in large tanks depends primarily on
the accuracy of the temperature compensation, which is inversely proportional to the volume of
the product in the tank. Volumetric tank tightness tests use a preset threshold value that, if
exceeded, is the basis for declaring a leak; they employ a waiting period after any addition or
removal of product so that both temperature inhomogeneities and structural deformation will
have a chance to subside. The thermistors used in the Griffiss experiments were calibrated to
iv
84

-------
better than 0.001°C and spaced at 30-cm (12-in.) intervals. The data from these experiments
suggest that, at the thresholds typical of those used in volumetric tank tightness tests, small leaks
(up to 0.38 L/h (0.1 gal/h)) would be difficult to detect even if the waiting period were sufficient
for temperature inhomogeneities and structural deformation to subside. Vertical gradients in the
rate of change of temperature near the bottom and top of the tank and horizontal gradients
between the centerline of the tank and the wall of the tank were still so large after the waiting
period that the thermistor array used in the Griffiss experiments did not provide sufficient
thermal compensation. The data also suggest, however, that if thresholds typical of monthly
ATGS tests were used, reliable detection of leaks as small as 0.76 L/h (0.2 gal/h) would be
possible.
As a result of the experiments on 190,000-L (50,000-gal) tanks, the important features of a
volumetric leak detection system that would have the performance necessary to meet EPA's
regulatory standards for volumetric tank tightness tests have been identified. These features
include the instrumentation, test protocol, and analysis. The experiments suggest that volumetric
systems now capable of testing 30,000- to 38,000-L (8,000- to 10,000-gal) tanks can be used to
meet the regulatory standard for testing 190,000-L (50,000-gal) tanks if (1) the duration of the
test is increased from 1 or 2 h to 4 h or more to ensure that the vertical gradients are accurately
measured and to reduce the ambient and instrumentation noise, (2) the number of temperature
sensors is increased from 5 to 10 or more so that the accuracy of estimating the average
thermally induced volume change in the layer of product surrounding each sensor increases,
(3) the waiting period after any addition or removal of product is increased from 6 h to 24 h or
longer so that the horizontal and vertical temperature gradients dissipate, (4) the average rate of
change of temperature in any one layer or in the tank as a whole is small enough to allow
accurate temperature compensation, and (5) an accurate experimental estimate of the constants
necessary for converting level and temperature changes to volume is made. The experiments
further suggest that a multiple-test strategy is required to meet the tank tightness regulatory
standard.
The duration of a test depends on the precision of the instrumentation and the amount of
ambient noise present in the measured volume changes. The magnitude and frequency of the
ambient noise observed in the Griffiss experiments suggest that a test should be at least 4 h long.
Given a certain precision of the level and temperature instrumentation, the minimum duration
can be calculated. Calculations based on the Griffiss experiments suggest that, when the level
v
85

-------
sensors have a precision of 0.0005 cm (0.00025 in.) And the temperature sensors have a
precision of 0.001°C (0.002°F), the test must be at least 2 h long. When the instrumentation is
less precise, the test must be commensurately longer.
The number of temperature sensors should be sufficient to cover the vertical extent of the
tank, with denser coverage near the bottom and top of the product, where the rate of change of
temperature and the gradients in the rate of change of temperature are greatest. In the Griffiss
experiments it was observed that, during the first 9 h after product addition or removal, the
10 thermistors equally spaced at 30-cm (12-in.) intervals did not provide a sufficiendy accurate
estimate of the rate of change of temperature near the bottom of the tank, where the largest
changes in temperature occurred, or near the surface of the product. (Even in the mid-region of
the tank, 30-cm (12-in.) spacing was not sufficient in cases when temperature reversals
occurred; this, however, can be monitored). Thus, it is recommended that the thermistors at the
top and bottom of the tank be spaced at intervals of 15 cm (6 in.) or less. Reducing the space
between sensors reduces the volume of product in the "layer" around each sensor, thus
minimizing any potential measurement errors.
In the Griffiss experiments, a waiting period of 4 to 6 h after the addition or removal of
product was deemed sufficient for the dissipation of horizontal gradients in the rate of change of
temperature that were observed along the long axis of the tank. Those observed between the
centerline of the tank and the wall, however, were large enough during the first 18 h to prevent
the reliable detection of leaks up to 0.38 L/h (0.1 gal/h). It is therefore recommended that, with
large tanks, a waiting period of 24 h be used. A longer waiting period may be required if the rate
of change of temperature is very great. To determine whether the waiting period is sufficient, it
is recommended that a measurement of the temperature changes in the area between the
centerline and the wall be made; if this is not possible, repeated tests should be made until there
is no observable change over time in the measured compensated volume.
Ten potential sources of error in temperature compensation are discussed, any one of
which may be large enough to produce a testing mistake. Since all errors in temperature
compensation are proportional to the average rate of change of temperature during a test, the
most direct approach for improving the accuracy of temperature compensation is to wait until
this rate has decreased substantially before beginning a test. This requires real-time
measurements of temperature.
vi
86

-------
This report was submitted in fulfillment of Contract No. 68-03-3409 by Vista Research,
Inc., under the sponsorship of the U.S. Environmental Protection Agency. This report covers a
period from 30 November 1989 to 14 September 1990, and work was completed as of
30 September 1990.
O i
vii

-------
Appendix A
Overnight Test Begun at 1510 on 27 August 1990
The time series of temperature measured during the overnight test
started on 27 August 1990 are presented in Appendix A. The raw
data for Arrays A and B located in the 76-cm (30-in.) -diameter
manway at B and the 10-cm (4-in.) -diameter fill hole at C,
respectively, are shown. The time series for Array A are presented
first. The times series are presented according to their location
within the tank and on the array. All of the product thermistors
located on the vertical portion of the array and in the product are
displayed as a group; because the display software only allowed
three time series on a display, several graphs are used to present the
product time series. The thermistors on the horizontal are grouped
together in one display and the thermistors in the vapor space and
the air are also displayed together. Appendix A also includes the
time series showing the difference in temperature between
thermistors located on Arrays A and B. (Refer to Figure 3.)
88
i

-------
f o :i)
ih tmm	jw
mm*
I P	'J
* "!
° :•	gd

H 1
=1 i'tt
TI Ijfi
-------
Chanrsel  2© 22 23 Temperature'
T««"d«"-«
-------
C-H^ nn& 1 < =. > 24 14 16
T €t?*p ernt u re'

, v *
«b:^ ...
Y/AWVv
»
26 » S0

t
i
«
i
i
t
i * «.«>%**
24
14
4 y
A
2©-75

••?« *?«
23..S3
Z0. <&W
L
p.,i
II " f'VV'm
I' I ' '"vvvV
*W
2S.45

"Vn*.,
I
20
15
£0	2=
TI iTw Ci~fOU.r" £¦ %J


01
* ,y ¦
4
-------
H!l 1 r-« WV /
* I W# * «	~mm" t*mm §
t-'i t-=u ii iei^
i lfr,e iisr i s:
4
X
"« 3i
X 411
i f 111m r ¦ -=*. l ur "f
28
I
T'T'. nri
>C'i«
21-40
7't . TTt
*0* 00

¦I -3 J
X «• i
I
4 rs i
X O J
I
ift n».©	25
T1 iliS (. i"il!
36
33
Op
5
-------
9
Ss
Lf>
02
' «.JTin> IS A»1T »

O.;
s I
0?

\
't*
\
T T
I- ~
£1
\-
H.

"V*
_A^^i
?T
TZ
*T,
-I Sen
A. J1"l *1 ¥>. Jr=* »-»ltl^ I
T T
fr *¦
I «-40!-;
• T
. h \
«*¦. «#§*«*
*=?»M t
% TAI M IIP-I ! ""»
S S.V<
"yw
-------
to
0)
s>
s
»
cs
<5
hj
o
Si
1"
01
J
	_^*y mm
ill
1.1
c:
i;
tfi
to
oi
*A
©
y
to
r-j
t-i
CS
ho
I-*
i\1
-
M	I
\l
UJ
M >Ii
w. *[
ft.
Kj ill
9: V>
H
<9
a
u
1!
a1
>+
£
10 10 10
0\ n-* \J
-------
Channel  7 4 3 Temperntur e
e>i=»g, r:
idZ&m
£&. 40

I' 1 •' *VVW-.yH,
~*
4
20.
2© |	
J
I .
i ••'
I "

19, toS
s - .,
i 9.4®
19-. 20
t
i
«*
a ,
:v »¦.
w ;•
v.yii,1 <<
t i*»i1 m
i..
.v.
:;» v.A
> t "A
" V» •.
if*;
' ^
»'<
Vi 1
¦r*x
A.
' ' *
|1a

,ee
i
i
is.se
10
15
2©	25
TiJue f,
-------
6
9
o
mrn i > ai» t i
S£
0£
9S

•%A
'fc..
"K


"S.
'*>
••«v,
Vtu
N
"iM
*A

Wi
•Vn
S J
Ql
0S "QC
SUtfK M !.
f ,f yx. i.JI-
f II
ir i
«<(Lh
il
H
i»
t
t
I
#
, I
I I
' IWMlft It
7F llliil.
'» tVISM
i I'flH
i tm
» ¦ -W1
Ml
II
i
i
I
wii
*r u
.. 4. 1 Mf
"l'«
HL1
1
:s'0,-
*C*RZ
9C "Pi?.
ss*es

ZS'&Z
*0C
"1
99 "OS
&9"&Z-
i
X
j3l ._JY"l Ifr.	1110 1	Gj
"ss* *z£ is *wi i"ss^	®
-------
< il«« -SW1.«&
Channel <&> 19 5 6
Tl* 1
& I
i.
"1
!
»..


>*•



J-S3
s
(
8.8S
, J
13
15
26
25
Z&
10
o**-
«l/ f
-------
h!i i r*i xss
» * *W» 41 *	W	*
I i rri

#	if
*"">¦«— — — — — ¦» «'* — >>
L-i wHi If JL Sis..-1
c.«
!•—« £Z> K~- 1
*mw" "*¦» B «*)
»-li
I .tlll_« fe.r «_ u.r *<=»
fw

j
VJ I
i
C* i
7 I
	i
{
i I
I I
< I
i:
,*i
Mi
V
,r
fi
)!
un.
k
m
"i
m.
I "h
« M
.j™
21
ie
15
20
25
3©
35
I 1 !M*f «,« IUUC .
Clfc
•l/ J
11
-------
m
10
(Nl
tHI
(M
v4i
T~
t
L
\
\

I
V
\
i«
L
4i
iX
£
*
H
Ml M
l|l V4
h-4
:L Ifi
>» CM
to
in
>1' >1
i3
•i-j
V- u'i o
r-v
pi
M
n
0)
c
C u
c >t tn
£ »•
Ctf O ft
V


iN
ir»
Q
ID


5)
*
•
«
¦~"I
•**
fi
CH
C-*
N
«
C3
*
Ci
ll)
\
05
w
m
m
>'w
;S
Q
J"
»1«
1
u?
o%
'3
¦N
V
5,
t
x.
n	§yi»»>-»i<>«i
i»
iS
-------
RUN 82/
IAIl I
Kl
unHii
JLJ r^Zr 'mmm§ g	,
*•"1
1-1
i »"S I-
'"Cm" H	|
0. 00
¦0- 1©
¦H=
i
,r» Trf-a l
i .-¦!
X "T
i.
i it
i ft
i ti i
i
111 II .
ill! ill i
iiH Mi i
Hi! A it
Illl IIII
Iftli II II
nan.«ii
i
j i
i i
i i
ii i i

J	L
4 *:
J. K-'
¦I o
A «—«

«-~i .-j
T im(0
•"^Ji v§
-¦v_«
oo
STQ
l"	I
*¦ « t«w s-s. I
100
13
-------
RUN Q2~P
«—*1 IAL I
"J ""j ^"*1
4JCSI <=T *— ¦=¦
t-k| tAL I .4
unHi^ *"fr
M = M.H
0 ^ 0^i
*=? S %3! c^=
s
0. 00
,-a »-»»—«
*£.» m 0X1
lyi H*X
\mJ* ¦ W 1
1*'3i i^i i*
%l* . %yo
H _ H
4 n
• x *3
14
1
I I
• ^ s:
1 1 ili
iilli f« i i ftt
(fii ft

111


* V "l ~'"lk-^w ^

-I £
x •»«
¦I o
j. w
ML J|
»' tM

*TnU>
TfS
i_IU
X t mo
4 •*. 1111—
i"* Ki-»i i ~->« 1
V t C W SAI —* 1*
14
101
-------
H!i ir-i
> »• »
,-v| |,.\L I
u-ni-in
Degrees €'
O.04000
0.82900
t-Vi I..SL I
L-nMii
0-SGSS0
-0.02000
¦0.04000 1	
ii il	I
!!!!	I! i
111!	li 1
ilii	li i
III!	if«,<
il I!	il lit
Hi!	Ifm
y ii	iiri<
in
fit
u ii m
in jiiJii
I'iMi*
i	<
ii	i, i
Si j.lTM i


1H
iCN


22	24
lilt*?

«>£<

15
102
-------
Rl Ibl &2P
B » 'mm' » *	"mm" ¦*¦¦> a
.-*1 IAI ^	i—-l 1AI I O
LnMiii^ — L.nMii o
Decife-es C
0.03000 I	
I 111
II UIII.V. «
ILMNUi.
«il Ml
tui t li
(til ill:
-Q.kti^kSkt	
P!
32
2S
26
IS
14
C<~tOU.t~£
16
103
-------
LI
foi
i"!^»
OCr
	j	
mou)
auji
wc.
jm% T
n t
7 t

-yH
ir 'ni
f?T
-f 98 "0-
4?0 SH-
I * i^e
MM W
"?*ra ¦ q
¦ f^m
*3
QG| s pi
W KmJ*
s-tn * r>
id i. ~ id
-=a
ki§-*i_i--i
I 1VI !•_'
I <5. -=&^r
•ytiJoy
Ml-H-I**!
I 1VI lv.1
m i.». r *
r«4i ih
• »» »mw»
-------
»
0
1
1
©
0
t
u
¦
KH
K)

ui
M
Q
Ul
^ ~
J
p
0:
CO
H hj
¦M
A f-.j
. M
IT L «.
P £
•-J
l.ft W
v Cr,
W
CO
W
®
W
1
1


©
CD

«3
ii
¦

H

©

©
©
01

©
1
*^csC:sssk:S£:C:
r

_			1
X

2!
1
¦Wo'
-SSE?5' H&	OD
il	h* kh
W	CD "U
O I
O
x
3>
mmr
mCm
%L	Q\
<£*
"5
-------
Appendix B
Overnight Test Begun at 1441 on 29 August 1990
The time series of temperature measured during the overnight test
started on 29 August 1990 are presented in Appendix B. "Hie raw
data for Arrays A and B, located in the 76-cm (30-in.) -diameter
manway at B and the 10-cm (4 in.) -diameter fill hole at C,
respectively, are shown. The time series for Array A are presented
first. The times series are presented according to their location
within the tank mid on the array. All of the product thermistors
located on the vertical portion of the array and in the product are
displayed as a group; because the display software only allowed
three time series on a display, several graphs are used to present the
product time series. The thermistors on the horizontal are grouped
together in one display and the thermistors in the vapor space and
the air are also displayed together. Appendix B also includes the
time series showing the difference in temperature between
thermistors located on Arrays A and B. (Refer to Figure 3.)
106
19
-------
Hun jKi^y | i |Tj0	1 £•£
« -	M <¦¦¦»	Tf »**  «Mk «w» «• i.*. •"¦w 1l^,,i It ? *' ""ii • "•"v
L-l i-di il ifl	I fc'lllptff'^l.Ur'b'
Besides C
A'is
16
14
iO,
% 4
.11 .4
, ruy«
, 41/ vrm
qIi f/i ' rui
i t, .	' «, it
I i! . Uiii i < '« m
i i.i .aitmu '	'i. in
i i ium<*ti»	'iM i
il/IMl'l 11 \
SM '
i i»*	i m
.m
i.i iir	\
18 »«	|
/II I	'>.
p	k
'I
t
II
II
II	I
II	k
M	'J.
il	!
ii	K
ii	i.
II	«4
il	n.
m	u».
K	"H
II	1
II
«	St
II	I
'	s
!	m
V
i	H »
I	' '<>A
1	v u
1	*1
I
wn
\
%
I
"ik	„*>
v>i. iV
*A. ff
f
v*
I	i
I	I
iS	i5	28	25	3©
TI <7e5 t.uOUri
20
10?
-------
rw.i i	i xuw
Oh*nne1< s> 12
f:
T emp erst t ure
5©

it, 4®
*# ^r%Tk
«&x •
-I
I il
Hi
, < uK">
% Ji/^"
	*i\wr''
ill( VMT M
It <'«y
. /«!
-f ^t I
A i
J
4 c I
A3 |
r't . TT-t
21. 1M
r
i. •*
i; •-. •.
t::*
mv-
•A^,k
?
.1
:«
j
20. 
-------
t LiH*sf
Chcirm^l <£ > 20
f:
T ^mp er-sit u re
4 «=*.<*
> « ¦ta'O


20, 00
j£MH
i
'•¦V, „
19. 00
U,
«l
& <
1.1
I I"' Sill.

i«s» aw.
10
20
25
30
35
( i.
-------
iz
OTT
' c. xnrii »•» aniT i
S£
0£
QZ
or

**•».» I
•,Tv*vu«
"ff
> C^T
I	^
!	. _
I	+!»7
I	§*¦ » *
, , J. .'. t\ V t,
't
»«y*ia7
tnc-
0^*02:
0£
mw "
06 * Piz
>z-a-3 4m&±
9T f I f>/3 <•» > [a»jusqg
SST.JAC »(»T I
-------
f-£f | f"*§ iHI 'y'rj/' I 1 fTi^i	"l £¦**
• i	i *
Channel (s) i*?
>1.8©
i e'ttiM er -
-------
Channel <«•> 13 11 10
tr:
T&mp er-ett ure
/»A
/
—**
tr
S3
IS
i'l
ii
i I
i
I 1
i V
I \
A
i.
* A	f
JL 1	{
a ru i
JL « J
10
15
28
30
35
« X (l
-------
<	OTT '
Chsnne 1 =•> 27
TlPQf'pee. r:
2 J 26 Temperature'
I

21. 40
¦7i TCI
'•zi,
>1 . 30
i
* 1 *
£ /" I
*,W-
li'lt fc •
*¦' i*i
»<1
* '
»
i
l
^ 1


: .. %
*4*1 A	
,y!iMVT,fr
i.ldL.il i, >«¦> AJIW. vV—
2&* SB


T L««5 *,*~i#3u.r"
^4.1

113
26
-------
t\, St
a
L
*
a
£
*
!~
l

Si?
-£
i/>	r 'j
-l-«
!l	"tf
ill
«
r-
n«
Is
•i-4	/».
I—	tf| ui
tj-	*1 y't
(•J	Oi 4!
CO C 41
C L
C ifi CP
:S £ 1'
it U Pi
Ca
IT)
es
c\
©
©
o

<3
in
$
ft.
f-4
-
, L ^ •<& -
m
to
<7
rH
^*4
u>
CM
V
o
© JT
CM
0?
6
••a
r*.
eg
Ifi
©
Q
Q
»
©¦
in
©
w
*
OS
-------
§-*mi-j jKvy i i iT|0 'zi&F' 1 0:
Channel 8
2&* 70
¦>*
rtt,
20. SS
f
¦?0 ^CT
k
i
. i
¦\4.
T^i

i $mP 0r "-A t. Llr" €¦
!;. ,
i
nuii

f
r
•»

«kj.
2&. 45
16
15	2&
Ti««s ('.hours 5
25
3©
35
28
115
-------
6Z
91T

3 -J'nci'4'} ws 12
££	92
St
or
98
I

'• I
.r

P»7
-I
«*¦ '
£ T
9^Jt $>
f i
. ,1 \
fyV"1' vr
' 11 If
fl
tl
11
I
I
.	| 09 '
1
0© '
A. JY1 ~i P. villi A i
T
»>
GO'
c:s Ti=ll II ITP-I »*"-»
x — .»• L — — — — -1%_*
L -wl^S "SM.U L t
.* —W	• # "U-"- ¦ *
*—I i liH
-------
i. Uthf Otff ' fifSi
Channel  0 9 6
T&mp era t u re
i
7'4
28 |—
i
I
it
il
H
)i
I 1
Ml i,.
H/W.
"4	\
*3 j
«—«	i
y	i
'	i
^	i
yli
i ij

yi
„!V
;»'?
ii
.mrr*
! i
1/
I	i
h'
it
ti
t(
U
it
II
U
II
II
II
II
II
II
II
II
r
IS
16.
it*
15
2©
25
3©
35
i i. <¦(>=? 1.1 t'ju.r "=>,
^fl H"1-.
XjL
30
-------

n
.1*5
¦1-1
-txi
*w«
.fU
KJ
W"m <$ « ¦ *
k1 ir-i
,—.» I..SI. I
I—I.-Xi, l
/I, 4 n , - -
...... J /I nS>. Jn
-------
m iw
• * - M *
»—• I |Al 1
•—I »,-M I
.-i
Begr-ees- L
M 9	j	
fU
rz-r*
L-i L*"t H
,—1 ,—V s j
• (.•1 PI .7 I—
.Q
f% si
Li
MA
«_«
iJli.
i mill i i
itifiim
tptii ~
;ii
till!
Hue
(
-------
KIJN 	
i.-si. i kT
«^-I I.»X«. I
u-nt-ifi
ttegr*
(J
0.01000
0-00000
-0,01006
I
02SQid i-
-fej. y.sww«
-0. 04 BOG
I lil 11 I
ii II.i
liii
iSliiti it
If US U II
lit 1
n fii
.iiit
IliiY i il
m u u
I fii Mill '.id
illUli M .11.
ffUiii.iii

'rrrftris 	
ft it w
-©. esse©
i-*
i®
19
j£&	XjC	jZH
Tiros	!



R»pf oduc»d tram
b*«t	copy.
33
120
-------
Rl IM
.""•I IAI I
*S^lS L»
G. 01CU3©
,4
t""NI l,*\l, I	t*-"^
unHii o
0 _ 000Q0
ft
i H	I
i I!	. , i
f ii	i (I
I (1	ill
i i ii	ill
I
-t*. U 1 ttwtl
(II
i in
i tin
I Sill I
i mi
i	iiihi
ii	iiti ii
-0.020O0
-a.33090
-t). tv=*wtu?
14
i
Ii
I 01
Mil
III
III .
iiiiiH !i.J . !
ll.llilMt JeM til .Ii ill i <
		 jlilllVI' li'l f T" TTWIML
III 111 ill II
I (III*
II il lllf i
ii it ir 11
k dt
WVI.OI. VI (t< U. t.
" ' "Trwr
16
IS
20	22	24
T* J — —
I i. ««*=*	,
28
3©
±21
34
-------
t-V|	I 4
L-nHH I
§*
t^*» IAI 1
L-nHii
M
.£%

»-a
¦«£.!
»-a .•*
CIO
¦ L-i _ L*i!—J
I7IP
•to . HJjC
i/f «A
I!
»i, It I
I ill il i
Hi il I
I i i il i
I
J
ill! i
111 I
t i
I I
I i
II! ill'
i
11^	III	I
II!	Ill I
III	HI	i II
¦ ill	ffl	I, il JJ
.... |
«{ii iHiiiiiii i
•iii iiiiiiiiiiui
A
A I .
* n u ii «. /•
fk iin.«n fft<« .
	 " JfiOT''
i.'ii ii uu if At' «j mi r v *
Ii il if 11(11MII fli ill I
¦ lilt Si IIfill HI W
"Mr ii iu ii i -
j.
-------
RUH 02?
•^•1 I.AI. I
HI
A •£«
J*"** ^5 |Ks*
i"-l IAI I
i»-nMiH
n

J ^
c* iSic*
¦to
jcta
.0 40
—0 « 60
Li Wii

•H./.
•I
JL
.-a.-ai i
r
I 5 ZM
L«
si £"!3i L—
A - "*t»
1 .*1
A -T
16
i O
j. w
20
24
¦S.O
"T -i ma i"* !-*»-%n *1
€ vfcfc III %•	">* € ^ %«** %¦>% € w—P mm
«->o
j£-V_«
._4 ^,1
123
36
-------
Appendix C
Overnight Test Begun at 1505 on 30 August 1990
The time series of temperature measured during the overnight test
started on 30 August 1990 are presented in Appendix C. The raw
data for Arrays A and B, located in the 76-cm (30-in.) -diameter
manways at B and A, respectively, are shown. The time series for
Array A are presented first. The times series are presented
according to their location within the tank and on the array. All of
the product thermistors located on the vertical portion of the array
and in the product are displayed as a group; because the display
software only allowed three time series on a display, several graphs
are used to present the product time series. The thermistors on the
horizontal are grouped together in one display and the thermistors
in the vapor space and the air are also displayed together.
Appendix C also includes the time series showing the difference in
temperature between thermistors located on Arrays A and B.
(Refer to Figure 3.)
124.
37
-------
HU.F!	! 2. JTsff	10S
Cf~t5.nn© 1 c. s ^ 2*?
Do9rk&<9'5 C
I fcflill-1 t=T *
-------
6£
SZT
S£
9£
<5-JTlCt|;s flrtllfl
SZ	0C
ST
0 T.

as"8r
00*61
"V,

u
. t»t
ii'i,
' VM
i II
... A ill/
>JI. Hill!
IIj'MII)'
'»!!!
nil! :
Ml •'
W:
I!! :
I C-7"
I £37
0S*£T
©O *©?•
@g'0S
83' IS

sc ec os <-s
VAT.JAC Am? I
f auueq-j
ftfo I mu
-------
r\'J.ri oo»j
Chmrtne*!
TK^or-'O^S
I 1 <«>=¦
s > 24
f:
J 4 J 6 T 6-mp erat ure
il. JS
21. 86

j* i
]
14 1
<€ / I
A£3i I
	«
7T1. *?<"¦»
J
i
*
| .***#>,
r
20. ?e
20.68
4
4
*f
;l
:l
:*
: i
:*
;>
:*
:i.4
;?§
.~•I
: 
-------
nun

Cm3.i ii i© I s.
Degrees C
I 1 mea
¦ A III .
— X ^ —
S=* A
Jgij^
1 © T ©uTiP	U.r"*<0
00
cs[0
« /
If
, wo
51.50
21.88
•I -3 I
X r |
i
•I l^i i
A I
t
At**
r8. 5©
;u
is
2®
25
i L m*sf *. I i&J'JLr "2» ,
36
35
1%
41
-------
Kl I ft
.1*
I 1 ffi£5f

mrnm mmm mm. T| fc»m
C.-I IdLi ii lfc?i k
Sest^ees C
x
.»
¦I
J-
¦i 4
J. A
i fun-* wr •<*. <_ u.r *te*
*&» *2SV
IV
Uvl

/"
-------
to
M
*
d
&

M
M
©
T
w
Ki
tfl
C3
IS O 3)
i* 7 c:
ifl a'	b
"7 J
'i 3	£<)
* C4
i," C5
i~! la
v
W 1'
\J
U*J
Hi iti
W it'
&•. iri
—i
*
a
v
t
«+

1
t	I	I
Is)	IK)	IK)
iQrs	»-*•	\J
-------
Chctr«r»€-3 1
s.> 7 4 3
r:
T eriif' c-rat ure
T'«. =iO
.1
A
#•1	if*
4
«A>*
\:
_ r;
>B, OS
19, 50
I
L
IV.feJM

« /
Cji
'«« »
¦« i
.
#JS
%k *
• . i< <
x*
y
y
v
>	,
*	,
*	,
*	,
* ;
» 1
*;
i .
i
) .
*
i
i
i
i
)
k
i
V
!r
!#
h
h
11
; *?.
* tfi
«C
i;
i' *'
;i.«.
s 'f
4*1 * *\

IS. 50
iu
*•£43
T liuv I uOUr
jiii

131
44
-------
•	*	*(—*	*	¦ A ill ¦—	- *— I «•> "»
X C 5- ^ o T"©ITip Gr"""5iil Lir"*©
Degrees €
2©, <>8
7'(H . AA
L_
I.
it
» 
-------
CSUA < 0-->^
Chcinne 1
4 LWfsf o*=»r
;«.> 19 5
r:
J.*-Ss
6
T &mp er«v ture
t't« |
!2.30
.00
f

j	
I
/
I
i
i
2i.50 (	
j
p.
• *
*	i
#
".I
¦I
Jl
*	I
it
w
u
;*
;*
:*
:i
:v
:i
;i
:t
:i
:*
:*
:i
L.
4 r*«
JL
/ (
l

Xl.kft-J
ku

/¦.'
t 1
•: ;
".!*•
,s

* V
t;
28. 50.
'iS
15
2©
25
30
35
133
46
-------
w«» r-«	I t rr«<=» SPr t <=•-
* t "W* i 1	%—¦ V—- W	* A III -mm	'mm' 'mm I	'mm a
^.•1"*Icil il Ifc^ JL *v is*
0
h
o
Temp ©rat ure
Usgrees c
-<£*•

r*v..
Mi
A

/
. J
iA
J*
M
/
! f
i r
u
V ,
! f-
N
it
I f
I /
I i
I I
\ I
W
\!
, <
O
7
.. J
¦x\
s.'fei
IS
Is
I X
I.
».
\
\
\
. J
' ^4..
>
'« i
V
'V
Jr.
ft/Jmi t.
„ A
u
28
i 3
2©	25
TliTifi"	'•
38
35
47
134
-------
h)
-FN
00
CO
CTT
fr.
CJ
6»
yi
h>
H C)
Si
«I«
;f
c>
Ifl
'-•* M
yi
u
61
10
C5
•-J
r4
YI
;
!
u
*A
yt
-u
Si
<3
'3
©
K>
CJ
V/
w
;»*
i,
*

« O 33
if 7 p:
".A a1 3
¦i T
>t 3 05
it <5 CH
in m cs
O I" H
V
£'
M. ill
'-"I
O'j
M iti
iji r-
!"•
ill
M »i
II—»¦
IK) ii-*
01 «
H
D
U
a1
<6
-------
RUN 8'
•~-l 1,-M 1
L-nHJM ojLI£.«
r».
-=f
»—-I IAI I
L-HMII
1 „ 0©
£* !0 01
Pi _ ACi
©.4-©

¦n
•0. 80
¦0

,a* si a*
K* m -t*ZJ
¦M _ Am
|	
<
i
i
i
i
i
i
i ,
f, i
it i
 l
ll

fx
w *
-v
(1
'I!
i
I
I
i
II *r
If
if
I
00
i .-I
1 o
J « 1
"Ti'S
i IT* cat i" i"""* i i ¦
I JL «tcw % « iwvm <
49
136
-------
R! IN &7ZCH
«—»I IAl I
«—»! IAl I
u-nMi'1
T'l ft J—¦¦. szz
jlj nsr i »sr «et -=•
I *

i n
1!TH

©a 05
53
I'Si'a
ji v U"
Pi _ Pi
. f
IM
»
ill
III!
Hi i
II I
IIJ
HI
iill
in
in
Hi
i!
1
I
w
I 1<
iL
I.M
11
«v

f\f\rA

0,10
4 .-i
A UT
16
X
1 o
X W
28

•74
«*L» F
o
I i ma
I •«» KICV-
»"" K»">i i k-->
".II «W -WW I .
\
oo
JL.KJ1
l"S|
50
137
-------
f-*i iw i—
«^»l l.»Xt 1 •-i-y
n t™*"! i "^ji
TJ <—* *>-- jGi J~S[
«^»i IAI I
L-.ni-iM
m _ §•¦».«-»

it*
C_«
I^V
«-i
*1*
i"Srt I
tmi r
i i
pfl , ft
il II rtftl «)i *c« %v__
J V'V|JV V w" i/
i ¥
"M - M .•¦

HA*H. (-
«~r j
86
i .-1
j_
i £
4. W
-I O •"5»"S
X «—«
•->-->
wmmm *.
T lme
v flour
-o
: %
-">0
-* « »
<_«0

138
51
-------
H?J ihi SaR
1 I Ik i »*4I
UflHil^lH1
0
i-^I IAI I
unHh
O-O40O©
in £v?£t£t£rt
fct, ui 1*143 tH3
in
m
!l f
/II!/
Hilt
U,.
iii
iji,
fi4f
m
i	irt<
III!
y
ii
fi
11
'i^\ n ( t i t f. fitt in.
'		 " 'r*,*y*'mir"t-*v
f.Mj4,'vv»/ysj.vW»ivT' tli»T"
I »t
w
-O.02000
*3. 94S9S
-8. £ie.03&
14
li
It
fi
il
li
II
1 
18
2©
24
:S
3©
< 4 «<« V « UJU.t *5» .
Reproduced Irani
boat available copy.
52
13U
-------
Ki ir-4 5-5.':«H
; : -—- a i	- -«~-
»-^i I.-XI. I
u-ni-in
Bestrews )
¦4 —1
x .••
»—»l IAI> j
i-.ni-in
0-05000
r~
(H. piACtCtC-i
u
VMr
. ,11
i	4
lil/uvf"
tn li
V f


_o« a * ruruc*
tm* m W jfc l-'t'C
lil
lii
lit
ts
53
140
-------
TfcT
M
t, S'vl
» %
t ** ** | |
VUI L j

i—*t
ot.
	,	
«u-o
83 SI 91 t^I
r*- t
1 ~ssn V
«*a.
o*
ii
!!
II
.A, , yl^VV*' '
•<»r
Jt
!l
! I
11»
! til
'(II
I If)
I
>\f
it!
ni
i u
ni
»
M
h .L
. . *., .*11 IftiMI I	till
.. ^v/w* it f/ii'ir	in	
* II tit If	II VII II
I tl	II W H
' r ii in ii
« H 'I! It
II
II
1?
II H
V II
I II
' II
It
CHT
U f
• C7f-
^		 *
<7*(7*
LJU -L-1
fll •«
<-¦ T
ism §¦
rk
KJ
Li.
L*"f
i£S.
O
§%ll—ILJ*-1
i 1VI l
-------
Appendix D
Cold Topping Test Begun at 0819 on 29 August 1990
The time series of temperature measured during the overnight test
started on 29 August 1990 are presented in Appendix D. The raw
data for Arrays A and B located in the 76-cm (30-in.) -diameter
manway at B and the 10-cm (4-in.) -diameter fill hole at C,
respectively, are shown. The time series for Array A are presented
first. The times series are presented by their location within the
tank and on the array. All of the product thermistors located on the
vertical portion of the array and in the product are displayed as a
group; because the display software only allowed three time series
on a display, several graphs are used to present the product time
series. The thermistors on the horizontal are grouped together in
one display and the thermistors in the vapor space and the air are
also displayed together. Appendix D also includes the time series
showing the difference in temperature between thermistors located
on Arrays A and B. (Refer to Figure 3.)
55
iiz
-------
|m«Ki
.pi.
¦J
CO
l~b
1"
JaaA
CO
T
iji
o%
4-»
C*2
•'0
H" M-
B ©
fB
:r
o
i-
**} M
w w
w
|»*Ar
4'i
i"*
Ul " '
K)	IK)	W
In)	Cf-
n r i yojj
£ o c
"? n '7'
!|l	¦¦'-
III I
m ,qc«
in H IfO
O
**|*|
—TT.'1'1" r"

-------
K» ir-4 WW
# f	»-
i *-*r
n CI K~* iQ
"i--i_ nn
20- 08

*N I
l_W j
* *—k Crt
X ? • N_«*L«
t™» i~Si »™5ii
IS
l^i
w
i ^3
¦I -I
i i ma
* «««
 i" hi-n i f
-.i
57
144
-------
huh
OUUL.
I l_.II-
ll iSSk g^l <£Sk <£Sm *
jlj msf^ ^ *«¦»' 4
1 - MM
"T1 fTk 01^1
«"-*i-ai -irt
¦ i** U
¦w ww
. n	« m _¦ *	¦
24
1 il
-I. 4
J <
I «
"7 Pi - .SM t—
2S.5S
20 a <40
o
o
1© 11
13 14 15
1 i mo
« «a» ««<%»
f hi-»i * **»•
% t (WVM *
58
-------
HUH
COOL
i i_«r
§ S	^Ss	®
Mkl
£ »"»
wu
<*W
OO OiTi
d£» 4bMK V d£» W
@0
«# i~n1^
iL. A a WW
«l *^1
J. »••
t *?
X %L?
•!"% J	.* »«¦%
/ 1 - iSM
*>* 40
-------

K» *-i
IJTu U
\\\\ U
UD m1i
j i
mmwil tflii
•w^pi iwi
"1 o
«¦*¦* 'war
if
m
i" "ii	i	i
LJ P I	J	
(¦••¦	-0	m
C-J	C-l	M
It
V
v
n
±.
IN
\ i
.. i
'i
I *\
!
i
10
vl
10
T"l
C -4 vt
L
z\
0
-H ,£
H V
1;
0 E
*¦1 'H
05
r-.
M
CN
4>
H
o
-------
m ihi
* M-mm-a M
ILmb
i kjr

r5fc3
¦O *1 o
JL. X m "tU

.J.liy
I,
t;
i;
}<
i'
i'
i<
-
-------
H!l ir-4 X'S'rt
rn * "mm" « 0	"mm- aft* m~
COOL TOP
ow
^*3 . feJKJ
*
&
1/
n
ii
p
.s i
1»—* err* I	
?-JWj—

o
IS. 50
o
w
9 18 11

I i n%£2k
• a.«t«-w
I*	I K"^^5 1l
% 4 (W*V»C	' .*
14
62
149
-------
Rl tbi &*7Q

»r-»
i «_*r
'¦ ¦	v
jjcr ^r i^nr—s k
MM
>-*y*
Ft ri
a «L.* U
¦4
JL
lfc_l
i „
i r
j r
i i
i i
j i
i
i *
i
*7G* cr.a
o

IS 11
4
JL •
4

|M^b{|^K| |
i iw*w\i _*
63
150
-------
!_¦ I ll*.l
rvwn


1 II II
«_« «_«1_
I I
«_« I
Ij ja »3 f¦> gan5 ¦
.u
*74

J. 25
1 6
H
li
»' 1
M
1 i
"*¦ I J
• I i
f*r fkki
« » ' WI
II
	-M
iji rf1r
f n 'i « f «¦
f »
I
i
,*K , ft.j ^ /•"». -t
yr K"

a
/'
I
if
/"
*
,<
If
i
I
I
I
14
Qi
iji
q.
1© 1 1
13 14 15
1 i mA
i A 4tt*W
i* hm i *-*•
# ® %¦»* 4 ¦
"I
«•
151
64
-------

> 1
Ki ir-4
B M'mm•a #
t-%	j
*_n_
hVv"
I_t i—j
i Kjr

!
i
xn
f-
J
1!«
I'«
i «:
i •"
i1"
i «
}'
i*
i;
•¦pi
C.« {
I ,
»:•
21. 10

•7i

Oft Q£?i
* o ¦
I _ MM I	
C51
w
o
1 ca
i i ma
1 A ll«N.
«« -I
x x
i •->
X dL.
i
4. *T
f hni i f~
N ( I W.SI
"« BC

-------
-------
Appendix E
Warm Topping Test Begun at 0820 on 31 August 1990
The time series of temperature measured during the overnight test
started on 31 August 1990 are presented in Appendix E. The raw
data for Arrays A and B, located in the 76-cm (30-in.) -diameter
manways at B and A, respectively, are shown. The time series for
Array A are presented first. The times series are presented by their
location within the tank and on the array. All of the product
thermistors located on the vertical portion of the array and in the
product are displayed as a group; because the display software only
allowed three time series on a display, several graphs are used to
present the product time series. The thermistors on the horizontal
are grouped together in one display and the thermistors in the vapor
space and the air are also displayed together. Appendix E also
includes the time series showing the difference in temperature
between thermistors located on Arrays A and B. (Refer to Figure
3.)
66
153
-------
fST
ST PI
1 *%¦». ."¦» > t v
I	.*
Zl
dul
IT
v t
»* I
©I
£3
o
01

.A-'
/
Jlf'
4>lj
f"
. W
,lV *
r*i
JSI r
Ar

r
w
!
f
..W, rifu'l *
I «V? -»l Ml MM
WVH.VM Al 1 h
v v vi || V r 1
' T
1}
*
H
*1«.
5 «=i «=• fc« fT
I^ti i
m ¦ i i
i is. iUM
L*J ^""1 *m m* I " ¦
~y	m
k If—1 VJ
1*41 l»—I
-------
I_> 1 Ifrvl
I—P «C 1
»Z3._> _L
|.J fvf
*"••1—11 "«i i
I | |i_B
i «—*«
JJ l^1 f2* IE* @!
28 ¦
£ il*
•^iZk j\ ijti
.ti

j£lk3 m H3k3
j
.£.«-• J
•~5 j~~
j
1 Q- P.&
IV m
4 O ^lQ 1	
j. m —ru
iQ
7 ¦ (inta*1
19- 88

¦•*V
O
18
! ime
i -I
X 4.
12
(hour:
i -T
J> •*»*
*5
14
c
68
JL.55
-------
«_¦ I IK. I
rM_in
jm mm
O.J A
wni "«i r
i i ii—*
R Ul
		u—a
"T»i"S
it« « «** i£«
"V

2k$ 5 *& wt
"7ft j£.£*
v.	MMMT par
<£ *	aii».
a 	
V
"V——
•-J--J
o
u
« I
i IWSAI •
69
156
-------
0'*» Pv ©
t"4 H T"l
Q.
•pHI Cjl
|v*l I"-"
OQi
|j£an
'Hi
oc
jCm>
U
--
vIm
»v
1.
m
«
Q
w
¦
¦M
(4
t,
/
i.
*
11
"HI
CM
to
n
w
Uk*
N
M
J
i
i
*
J
J
I
I
I
0
f"4
N
O
11
CM
©
©
W
'^fir
10
rH
¦tf
iH
r;
Ml
itrw
3
-------
!__• 1 1K. 1 4_* «C "1
i.iniJm
F-irir -" _
I_ j—|p
i *«« i i
i.
25

¦ <
¦0*Ti
¦T* «
X
/ „
r
*r
>11v
. *
-------
«	*i iki
r^i_j «^i
^Vb^bbP < *
¦ZDi «_3 JL
i -11- "i«_»m
Hni "it i
~*« 			 _
I I gU3l	jSSii ffiSt ¦
1 L«I
¦i
4.
"7p
«-1
OiS
V
V 1
1 Si I—

91

4s ^ a '?~*Q
:©. 8©
20 "~?£3| L
~
g
1
X c_«
•i -I
1

14 15
1 *» mc» i* l™n-^» i

72
159
-------
20 - 68
mmmm a « • a
i_«l Ikl
f-^ *—* i
G"3" *1
»=?-_? i
• * -»~
I « I	lYj
rm [^f 8 § 1 i
5 * —»» liU « «5 BBf KBf
| j |Si §j |3i |5jif"
OP
4^m»
i_.
jd^.1 ¦ Mhty
¦PI- ?l«i
.-" L-4 WH
O OiT5i
W"* M ®LbJ®	|

io <£ fa
7 . ofc*
1*—«	j* iTT.
_yg ¦**?
19. 20
i O «i5i
± s- m w

^\.n a..
'V

4 *S5 Oi
± O a Oi
O
©
o
1©
ii
ime

c hours.?
14 15
73
160
-------
	1	
0-
T-i 10 'ft
I
I
I
\
V
\
1
lalavi
•HI O
|vHi
ijlQi
.i.
"IP**1
jC*>
it
D li
il"
"I"
1.
irn
l|l!
©
¦
H
M

©
111
N
i
s
v
:<*
%
, j,	"1 _
©
Mi
H
tHI
CM
©

•tf
iH
to
VI
L
C**l :5
^ 0
tJmm
*mmf
tH 9j
1H
0 I"
H
05
©
©
©
©

©
0-
00
¦
i
¦
•

•tH
©
©
I.N
«N
CM
N
-------
i—H Itvl
C3»_* JL
i.iQum
K«#n§ "¦! i
UK
i—
14
vflM^ «MM^
i
••• L
V I
Pi I
21
28

\
jr*
' ur
19
O
•I
T-i
1
-------
i_«i iki 0"T **
r\l_Jfi <5,-^3l i;
WARM TOP
Degrees C
:8.84
28. S2

.; v* -_,V
¦»V, «,»
_^*"W
«* V'rf
«=: i
j
25
12
28.S0
28. 78

\T~ **
28.76


•Vu /
L/v—

mmf*"
V—IV*

J*r>j
28.74
8
9
1© 11 12
Time 
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before complet*
1. REPORT NO.
EPA/600/2-91/044a
4, TITLE AND SUBTITLE
Volumetric Leak Detection in Large Underground
Storage Tanks
Volume I
6. PERFORMING ORGANIZATION CODE
FB92-114S66
5. REPORT DATE
August 1991
?. AUTHORISI
¦ James W. Starr,
Vista Research,
8. PERFORMING ORGANIZATION REPORT f
Richard F. Wise, Joseph V.
Mountain View, CA 94042
Maresca, Jr.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
CDM Federal Programs Corporation
13135 Lee Jackson Memorial Highway - Suite 200
Fairfax, Virginia 22033
10. PROGRAM ELEMENT NO.
CBRD1A
1t, CONTRACT/GRANT NO.
68-03-3409
12. SPONSORING AGENCY NAME AND ADDRESS
Risk Reduction Engineering Laboratory—Cin.,
Office of Research and Development
US Environmental Protection Agency
Cincinnati, Ohio 45268
OH
13. TYPE OF REPORT AND PERIOD COVERE
Project Report
14. SPONSORING AGENCY CODE
EPA 600/14
15. SUPPLEMENTARY NOTES
Project Officer: Robert W. Hillger (FTS) 340-6639
Coram: (908) 321-6603
16. ABSTRACT
A set of experiments was conducted to determine whether volumetric leak detection system
presently used to test underground storage tanks (USTs) up to 38,000 L (10,000 gal) in
capacity could meet EPA's regulatory standards for tank tightness and automatic tank
gauging systems when used to .test tanks up to 190,000 L (50,000 gal) in capacity. The
experiments, conducted on two partially filled 190,000-L (50,000-gal) USTs at Griffiss
Air Force Base in upstate New York during late August 1990, showed that a system's
performance in large tanks depends primarily on the accuracy of the temperature compensa-
tion, which is inversely proportional to the volume of product in the tank. Errors in
temperature compensation that were negligible in tests in small tanks were important in
large tanks.> The experiments suggest that volumetric systems now capable of meeting
regulatory standards when used to test 30,000- to 38,000-L (8,000- to 10,000-gal) tanks
will also meet these standards when used to test 190,000-L {50,000-gal) tanks if (1) the
duration of the test is increased from 1 or 2 to 4 h or more to ensure that the vertical
gradients are accurately measured and to reduce the ambient and instrumentation noise,
(2) the number of temperature sensors is increased from 5 to 10 or more so that the
accuracy of estimating the avexage t-hermallv induced volume change in the layer of pro-
duct surrounding each sensor increases, (3) the waiting period after any addition or
removal of product is increased from" 6^-h ..to 24 h or longer so that the horizontal and
vertical temperature gradients dissipate, (4) the average rate of change of temperature :
any one layer or in the tank as a whole is small"'TSBQ|igh to allow accurate temperature
compensation, and (5) an accurate experimental estimate of. the constants necessary for
converting level and temperature changes to volume is madeThe experiments further
suggest that a multiple-test strategy Is also required
17.
KET WORDS AND DOCUMENT ANALYSIS

a. DESCRIPTORS
b,IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group

Underground storage tanks.
Large USTs, Leak detectior
Petroleum, Volumetric
Precision testing, Interns
tank tests
9
1
IS. DISTRIBUTION STATEMENT
¦Release to Public
19. SECURITY CLASS (This Report)
Unclassified
21. NO OF PAGES
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220*1 (9-73)
-------