United States
Environmental Protection
Agency
Municipal Environmental Research ~
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-040 Apr. 1983
v>EPA
Project Summary
Petroleum Pipeline Leak
Detection Study
John R. Mastandrea
A study was conducted to provide a
viable, cost effective means for reduc-
ing the incidence and volume of oil
spills from petroleum pipeline systems
in the United States. Estimates were
made of the total quantity of petro-
leum lost and the amount attributable
to each major loss mechanism. A
detailed analysis was made of the oil
spill risks and methods for reducing
them. Leak detection and inspection
methods and equipment were
selected and analyzed. Costs of var-
ious options and spillage were also
analyzed, and preventive maintenance
programs for line pipe are recom-
mended. If such programs were imple-
mented nationwide, prevention and
control of accidental petroleum spills
from operational lines could be
increased significantly.
This Project Summary was devel-
oped by the EPA's Municipal Environ-
mental Research Laboratory.
Cincinnati, OH, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Transportation of petroleum through
pipeline systems in the United States is
relatively safe. But because there are
many individual systems of diverse
dimensions, age, material, etc., a real
and continuous concern exists over
accidents and leakage. Petroleum acci-
dents and leakage cause many pollution
incidents that are detrimental to both
the national interest and the oil indus-
try. These accidents result in the loss of
large quantities of petroleum, cause sig-
nificant environmental problems, and
subject segments of the population to
potential hazards. Even small losses
from a pipeline system cannot be toler-
ated, and it is the responsibility of
government and operating companies
to protect the community from possible
damages resulting from a leak.
The overall objective of this study was
to provide a viable, cost-effective means
of reducing oil spill incidents and
volume and thereby minimize environ-
mental impacts. Specific objectives
were: (1) to estimate total petroleum
losses and identify specific loss mecha-
nisms; (2) to appraise oil spill incidents
accurately, including causes, system
component failures, frequency and
volume of spills, and key factors relating
to spills; (3) to define capabilities of leak
detection and/or inspection techniques
both for detecting leaks and for deter-
mining the condition of the line; (4) to
estimate oil spillage that potentially can
go undetected; and (5) if feasible and
practical, to develop or recommend
advanced techniques for reducing the
problem.
The envisioned result of this study is
the development of an effective spill
prevention program for individual pipe-
line systems of diverse age, dimensions,
controls, etc. The program would be
based on scheduled inspections and/or
leak detection to test the condition of
pipelines and/or to check for the pres-
ence of leaks. The envisioned applica-
tion is to aid operating companies both
in evaluating the need for and in devel-
oping a spill prevention and control pro-
gram for individual lines. In addition.
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such information might help various
local and Federal agencies to evaluate
problem areas and available means of
minimizing the problem.
Methods and Procedures
The extent and nature of petroleum
losses from the petroleum transporta-
tion systems were studied to obtain an
overall perspective of the problem of
accidental spills. Estimates were made
of the total quantity of petroleum lost
and the amount attributable to each
major loss mechanism.The problem of
spills from the transmission line (line
pipe) was emphasized. Study of such
spills also provided basic information
that was used in the detailed analysisof
the oil spill risks and the capabilities or
methods for reducing the risk.
Leak detection and inspection
methods for petroleum pipeline systems
that might reduce the risk of oil spillage
(i.e., reduce the frequency of spills or
limit the volume of oil lost) are pres-
ented in the full project report. Because
of the high incidence of pipeline spills
and the potential for significant risk
reductions that could be achieved,
major emphasis was given to the detec-
tion and prevention of leaks from pipe
failures. However, methods were also
included for other pipeline system com-
ponents. Methods for preventing leak-
age by detection of impending failures
and minimizing leakage volume through
early detection of leakage were
emphasized. Methods included in exist-
ing domestic and foreign regulations
and current recommended practices for
inspection and leak detection of liquid
and gas pipelin-e systems were
reviewed.
The full report presents an analysis of
the risk of accidental oil spills from pet-
roleum pipeline systems. The serious-
ness of oil spills and the difficulty of
assessing the risk of oil spills are also
reviewed. Approaches are suggested to
compensate for these difficulties. The
environmental problems created by
spillage were also examined. A refer-
ence line (typical line) was used to ana-
lyze in-depth the risk of oils spills from
line pipe, and correction factors for vari-
ations from the reference line were
developed so that the spill risk (poten-
tial) could be estimated for most lines.
Simplified tables and figures are pro-
vided so that an operator can estimate
the spill potential of his own line.
Selected leak detection and inspec-
tion methods are analyzed for their risk-
reducing potential (i.e., their effects on
the frequency and volume of spills and
risks external to the line). Means are
provided for an operator to estimate the
risk-reduction capabilities (effective-
ness) of inspection and leak detection
methods for his own line. Estimates
were made of the capabilities of leak
detection and inspection equipment to
detect a leak of a certain magnitude
and/or impending failures. The
methods were evaluated based on their
ability to reduce the frequency and
volume of leak- and rupture-type spills
for the reference line. Factors were
established that provide a simple means
for comparing methods for reducing the
frequency and volume of spills. These
factors help a potential user to select a
method that will satisfy the spill preven-
tion program needs of a particular line.
Since costs are a major consideration in
a practical maintenance program for
line pipe, costs of the various options
and spillage are estimated and a cost-
effectiveness analysis is presented.
Preventive maintenance programs for
line pipe are presented and particular
programs are recommended. Benefits
of these programs are discussed. Pre-
ventive maintenance schedules for
achieving specified reductions in the
frequency and volume of spills are iden-
tified. Recommendations were based
primarily on qualitative estimates of
both the oil spill risks that exist and the
abilities of various methods to reduce
the risks. However, the recommenda-
tions were also based on other practical
considerations such as cost of inspec-
tions and spillage.
Conclusions
This study indicates that the potential
exists for serious spills from the line
pipe of petroleum pipeline systems and
that various options (inspection and leak
detection methods) are available to
reduce the oil spill risk significantly.
Based on the results of this investiga-
tion, preventive maintenance programs
for line pipe are recommended.
The component of a pipeline system
that is most responsible for spill inci-
dents with the largest loss of petroleum
and the greatest risk to the environment
is the operational transmission line. As
pipeline systems age, an even higher
incidence of pipeline failures is antici-
pated. Once a line becomes operational,
however, no guidelines or schedules for
effective inspection exist for U.S. pipe-
line systems. Furthermore, state-of-
the-art leak detection methods are not
commonly used. Even if they were used,
most methods are limited in sensitivity,
and significant quantities of fluid could
be lost before shutdown. The problem
becomes particularly critical for certain
pipelines such as those with large-
diameter lines in which high volumes of
oil can be spilled before conventional
leak detection systems can detect the
leak and initiate shutdown.
Though no methods or procedures
exist that can guarantee complete pro-
tection against a pipeline leak, the fre-
quency and severity of spill incidents
can be minimized by effective and fre-
quent inspection of the operational line.
Certain identified inspection and/or
leak detection methods used alone or in
various combinations may be effective
in minimizing the risk of a serious spill
from individual lines. In many in-
stances, the various available options
may be practical, beneficial, and cost-
effective. Furthermore, preventive
maintenance programs can be imple-
mented ( at significant costs) to reduce
the possibility of serious spills and
improve the safety record nationwide.
Means are available (see the full pro-
ject report ) for estimating the reduced
frequency and volume of spills using
preventive maintenance programs.
Such information allows one to esti-
mate future oil spill trends for a particu-
lar pipeline or nationwide.
Recommendations
Preventive maintenance programs for
preventing spills from the line pipe of
operational lines are recommended.
These programs should continue to be
investigated along with new and devel-
opmental leak detection and inspection
methods. The preventive maintenance
programs recommended in the full
report are primarily intended to help
operating companies evaluate their
needs and develop spill prevention and
control programs for their own opera-
tional lines. In addition, this information
can aid various local and Federal agen-
cies in evaluating problem areas and
available means for minimizing the
problem.
Because numerous variations exist
among lines and wide ranges occur in
the oil spill risk, it is beyond the scope of
this study to recommend programs for
particular lines. Hence recommenda-
tions are generalized and do not include
specific details for implementing
methods for particular lines. The pre-
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ventive maintenance programs include
scheduled inspections and/or in-situ
leak detection (some functioning con-
tinuously) that could be effectively
developed and implemented. If imple-
mented, the programs are expected to
improve significantly the prevention
and control of accidental spills of petro-
leum from operational lines. Nation-
wide implementation of such programs
is expected to decrease substantially
the total quantity of petroleum lost, the
total number of spill incidents, and the
number of major spill incidents. Esti-
mates of these reductions are presented
in the full report.
The recommended approach for devel-
oping a spill prevention program for an
individual line or group of lines was
based on the following steps:
Estimate the risk that oil will
escape.
Identify line locations at which a
spill may create special, serious
problems such asthe possibledam-
age to the external environment or
cost of spill cleanup.
Estimate the level of corrective
action to reduce the spill risk to an
acceptable level.
Identify the available spill preven-
tion options for achieving the
necessary reductions in spill risk.
Select the optimum methods based
on the cost effectiveness and other
considerations of the various suita-
ble options.
A general schedule for reducing the
frequency and volume of spills is recom-
mended in the full report. The general
schedule produced confidence that an
individual line or group of lines will have
no more than (X) barrels spilled and (X)
number of incidents per year. The
recommended approach is first to esti-
mate the risk that oil will escape from
the line and then to select one of the
following specific preventive mainte-
nance schedules:
Reduction of spill frequency
Reduction of spill volume
Reduction of spill frequency and
volume
Using the approach and indicated sche-
dule, selected spillage reductions of
greater than 25, 50, and 75 percent,
respectively, may be achieved.
Preventive maintenance programs
with specific schedules and applica-
tions were recommended as follows:
1. Most U.S. Lines:
Visual inspections of the line by
air or ground patrol (weekly)
One-call system
Survey by inspection pig (mag-
netic flux type or other compar-
able device) (every 4 years)
or
Hydrostatic tests (yearly or after
indication of spill)
2. Underwater lines:
Visual inspections of the line by
air or ground patrol (weekly)
Depth of cover inspection by
sonar or other comparable de-
vices (every 2 years)
Hydrocarbon probe inspection
(towfish or similar device)
(yearly)
Survey by inspection pig (mag-
netic flux type or other compar-
able device) (every 2 years)
or
Hydrostatic tests (yearly)
3. Large-diameter lines:
Visual inspection by air or
ground patrol (weekly)
One-call system
Survey by inspection pig (mag-
netic flux type or other compar-
able device) (every 4 years)
Volume comparison, flow rate
comparison, and pressure
deviation
or
Mathematical modeling
4. Old lines:
Visual inspections by air or
ground patrol (weekly)
One-call system
Survey by inspection pig (mag-
netic flux type or comparable
device) (every 3 years)
or
Hydrostatic tests (yearly or after
indication of spill)
5. Lines with two or more reportable
spill incidents within 1 year:
Visual inspection by air or
ground patrol (weekly)
One-call system
Survey by inspection pig (mag-
netic flux type or comparable
device) (every year)
Hydrostatic tests (yearly)
This schedule should be in effect until
approximately 3 years after spill inci-
dents are reduced to a normal rate.
Recommended developmental and
new inspection and leak detection
methods include:
Mathematical modeling
Passive acoustic array
- Retrofit (to prevent and/or detect
damage from outside forces)
- New lines (to prevent damage and
detect failures)
The full report was submitted in fulfill-
ment of Contract No. 68-03-2532 by
Science Applications, Inc., under the
sponsorship of the U.S. Environmental
Protection Agency.
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John R. Mastandrea is with Science Applications, Inc., El Segundo, CA 90245.
Richard A. Griffiths and J. S. Dorrler are the EPA Project Officers (see below).
The complete report, entitled "Petroleum Pipeline Leak Detection Study," (Order
No. PB83-172 478; Cost: $34.00, subject to change} will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officers can be contacted at:
Oil and Hazardous Materials Spills Branch
Municipal Environmental Research LaboratoryCincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
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