Distribution Integrity Management (DIMP)

"Distribution Integrity Management" (also known as "DIMP") is a regulation of the U.S. Department of Transportation's (DOT's) Pipeline and Hazardous Materials Safety Administration (PHMSA).

A Notice of Proposed Rulemaking was issued in June 2008, and the final rule was released in December 2009.

The regulation requires operators, such as natural gas distribution companies (LDCs), to develop and implement written integrity management (IM) programs addressing the following elements:
  • Knowledge of infrastructure
  • Identification of threats
  • Evaluation and prioritization of risks
  • Mitigation of risks
  • Measurement and monitoring of performance
  • Periodic evaluation and improvement
  • Reporting of threats.
Operators are given 18 months from the date of the issuance of the final rule to develop and implement a written plan.

In early 2009, NGA and the Southern Gas Association (SGA) announced the development of a joint collaborative to develop a framework document which would provide a foundation and the guidelines for a distribution integrity management plan. The partnership is based on a similar arrangement that the two organizations used in the past for the successful development of a joint Transmission Integrity Management Plan. Structural Integrity (SI) was selected as the contractor to develop the document under the direction of the collaborative.

The framework document will serve as an outline for distribution companies to build customized distribution integrity management plans that comply with the final rule. The supporting documents, templates and tables have been included in a "user's guide" that support the framework document.

The framework document and user's guide was developed to provide distribution operators with a document that could be customized to meet the specific needs of large and complex systems as well as smaller systems. Members of the collaborative have operations ranging from those that serve more than 3 million customers and cover multiple states and jurisdictions to those that serve less than 50,000 customers.

The document is available for purchase now. More information on purchasing the document is available on the SGA web site: http://www.southerngas.org/index.php/products/details/51/7/sga-training-products/nga/sga-dim-framework-document-and-user%27s-guide

From this common platform, each NGA and SGA participating member can then develop an individual program to meet the requirements of the final Distribution Integrity Management Rule from (PHMSA).

For further info:
PHMSA has a web site with further information on DIMP:

Order the NGA-SGA Plan for your company. Visit the SGA web site for more info.