Page 456 - Pipeline Pigging Technology

Risk assessment and inspection for integrity

1. Demonstrating to operating personnel, the public, regulatory au-
thorities and our customers the commitment to operate a safe and
reliable pipeline system capable of operating at its design capacity.

2. Maintaining the value of gas transmission assets.

3. Allowing scheduling of maintenance operations to minimize disrup-
tion and avoid unplanned outages for repairs.

The benefits of extending NOVA's pipeline integrity programme to in-
clude lines with no history of failure are perhaps more intangible and less
obvious, since the long-term gain we expect to achieve involves some short-
term pain. The projects do contribute to our operating costs, and may
inconvenience the operations of our customers, yet it is not obvious in
advance that failures would otherwise occur.
One of the intangible benefits of this part of the programme is the
improved knowledge about the structural integrity of the buried pipeline
system, and the reduced potential for future large, nasty surprises. Even
though some projects have shown that failures due to deterioration of
structural integrity are unlikely in the near term, the confidence in the
reliability of critical parts of our system provided by this information, and the
ability to plan future integrity activities based on factual data, has real value.
A second intangible benefit of the total programme, related to the benefit of
demonstrating a commitment to safe reliable operation, is the ability of
NOVA, and other companies that have taken a leading role in managing
pipeline integrity, to minimize outside interference in this aspect of our
business.
The guidelines for selecting pipeline integrity projects are intended to
introduce an element of cost-effectiveness that can be measured in the
tangible benefits of preventing failures. If we are very successful in prevent-
ing outages in the medium term, the value of avoided consequences will be
larger than the cost of the whole programme. It is too early to tell if this might
be a realistic objective. On the basis of results for completed projects in the
last two years, we can reasonably claim that the potential economic conse-
quences of failures that otherwise would have occurred in the next five years
represents 70% of the programme cost in those two years. The key to
improving this result is to improve our accuracy in predicting the severity of
deterioration, rather than simply the presence of deterioration.
At the present time then, we cannot claim that the whole programme can
be justified in terms of tangible dollar benefits, but we believe that the
intangible benefits are sufficient to continue the present approach.

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