Why arent the proposed distribution integrity management requirements focused on high consequence areas?
The integrity management requirements for other kinds of pipelines are focused on portions of the pipeline where significant consequences could result if an accident occurs so-called high consequence areas. This is a reasonable approach for gas transmission pipelines that traverse long distances. Much of that pipeline is in uninhabited or sparsely populated areas where accident consequences would not be significant, and it makes sense to focus safety-improvement efforts on other areas where consequences could be worse. The same cannot be said of distribution pipelines. Distribution pipelines, by their nature, exist in populated areas, since they exist to deliver gas to those populations. In addition, distribution pipelines operate at low pressures where gas releases tend to occur as leaks rather than ruptures. These differences make it impractical to focus on certain portions of a distribution pipeline where the likelihood of an accident with significant consequences is greater. For di