Page 278 - Pipeline Pigging Technology

Pigging for pipeline integrity analysis

PIGGING FOR PIPELINE INTEGRITY

ANALYSIS

THE DOT has collected and assimilated data on pipeline incidents for many
years. A pipeline incident is defined by the DOT as having one of the following
characteristics:

1) An event that involves a release of gas from a pipeline or of LNG or gas
from an LNG facility, and

i) a fatality or personal injury necessitating in-patient hospitalization; or
ii) estimated property damage, including costs of gas lost by the
operator or others, or both, of $50,000 or more.

2) An event that results in an emergency shut-down of an LNG facility.

3) An event that is significant, in the judgment of the operator, even though
it did not meet the criteria of paragraphs (1) or (2) above.

Table 1 sets out the statistics that cover the 1989 incidents for liquid
pipelines. Most pipeline operators' major concern is the mitigation of corro-
sion, but as can be seen from this chart, corrosion is not the major cause of
incidents. In fact, corrosion (internal and external combined) accounts for
19.88% of the incidents. Outside force is the number-one contributor, with
26.71%[1].
Table 1-A gives the same statistics for gas pipelines[2], which show the
same trend with 4.67% of the incidents caused by corrosion and 49.02%
caused from outside force.
This phenomenon is not unusual, and is proven to be true with all past
reports of DOT data. This fact is shown in the reports made by Battelle to the
AGA for the period 1970 to 1984[3], and 1984 to 1987[4].
In the case of the 1970 to 1984 incidents, Battelle's analysis reported 53.6%
of incidents were related to outside force. In comparison, corrosion ac-

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