Recommendations are often made that the operating pressure of a pipeline be reduced prior to investigating suspected mechanical damage in the field, due to the unknown severity of the dam-age. The ensuing question is: knowing only what can be inferred from in-line inspection and the characteristics of the pipeline, what is the appropriate amount of pressure reduction? A common recommendation is to lower the operating pressure to 80% of a recent high pressure level. Oper-ators may question whether the same pressure reduction is necessary or adequate for all pipelines, e.g. different Location Classes,...
Recommendations are often made that the operating pressure of a pipeline be reduced prior to investigating suspected mechanical damage in the field, due to the unknown severity of the dam-age. The ensuing question is: knowing only what can be inferred from in-line inspection and the characteristics of the pipeline, what is the appropriate amount of pressure reduction? A common recommendation is to lower the operating pressure to 80% of a recent high pressure level. Oper-ators may question whether the same pressure reduction is necessary or adequate for all pipelines, e.g. different Location Classes, and all modes of damage, e.g. rock-induced damage as opposed to encroachment damage. With some operations, pressure reduction by an arbitrary proportion is impractical or very costly.