Distribution Integrity Management Programs (DIMP)
APGA Issue Brief
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Background: During the past 5 years the Pipeline and Hazardous Materials Safety Administration (PHMSA) has issued rules on integrity management for oil pipelines and gas transmission pipelines. In 2005 PHMSA told congress it would issue rules for integrity management of distribution piping in 2007.

The Issue: Rules for the integrity management of transmission pipelines are very complex and expensive, requiring pipelines to identify high consequence areas where population density and other factors would result in a greater probability of damage and injury than the rest of the pipeline system. It requires expensive periodic inspections of pipelines for corrosion and other defects in these high consequence areas. Were such rules to be applied to distribution it would be extremely costly and burdensome since distribution piping cannot be internally inspected like transmission lines. OPS convened four government industry working groups to advise OPS on how to proceed. OPS plans to propose DIMP rules in late 2006, have a final rule out in 2007 and give operators until 2008 to prepare a written DIMP plan.

APGA Action: APGA co-funded a study with AGA showing that the major risk to distribution integrity is excavation damage, not corrosion. APGA representatives were appointed to each of the OPS working groups formed to study DIMP, along with AGA members and state regulators. The APGA members and state regulators succeeded in convincing the group that because of the vast differences in the size of distribution systems a complex, one-size-fits-all rule was not appropriate. The working groups recommended that OPS adopt flexible regulations requiring that each operator develop a DIMP plan appropriate to its system.

OPS asked the Gas Piping Technology Committee (GPTC) to develop guidance for DIMP plans. GPTC is an industry-government committee that develops non-binding guidance for pipeline safety regulations. APGA has two representatives on the GPTC working groups. Once again our presence has succeeded in steering the guidance away from complex programs appropriate only for the very largest utilities and toward a more flexible approach appropriate for small public gas systems.

APGA has proposed a simple process where a utility would assemble its most experienced operations and maintenance personnel, along with available construction, inspection and repair records, and through a series of questions determine if any part of its distribution piping deserved special attention. For example, if part of the system was made of bare steel and there was a history of corrosion leaks on that part of the system, the operator’s DIMP plan would specify steps to minimize corrosion. This could include coating and cathodically protecting the bare pipe, or replacing it with plastic over a number of years. The operator would then monitor the number of corrosion leaks and, if it found that leaks were not going down, the operator would have to consider additional steps to reduce corrosion. Through our Security and Integrity Foundation (SIF), APGA is seeking a grant from OPS to develop a model DIMP plan that makes it easy for small utilities to go through this process. The model plan will be available on or before OPS issues its final rule, expected to be mid 2008.

1/18/08