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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Gas Distribution Integrity Management Program (DIMP)

This site is administered by the Pipeline and Hazardous Materials Safety Administration (PHMSA). PHMSA published the final rule establishing integrity management (IM) requirements for gas distribution pipeline systems on December 4, 2009 (74 FR 63906). The effective date of the rule was February 12, 2010, resulting in IM regulations for gas distribution pipelines (49 CFR Part 192, Subpart P). Operators were given until August 2, 2011 to write and implement their distribution integrity management programs (DIMPs).

PHMSA previously implemented integrity management regulations for hazardous liquid and gas transmission pipelines. These regulations aim to assure pipeline integrity and further improve the safety of pipeline transportation of energy products. Congress and other stakeholders expressed interest in understanding the nature of similarly focused requirements for gas distribution pipelines. Significant differences in system design and local conditions affecting distribution pipeline safety precluded applying the same tools and management practices as were used for transmission and other cross-country pipeline systems. Therefore, PHMSA took a slightly different approach for distribution integrity management following a joint effort involving PHMSA, the gas distribution industry, representatives of the public, and the National Association of Pipeline Safety Representatives to explore potential approaches. This effort resulted in PHMSA's gas distribution IM regulations.

The gas distribution IM regulations require operators, such as natural gas distribution companies, to develop, write, and implement an integrity management program with the following elements:

  • Understand system design & material characteristics, operating conditions & environment, and maintenance & operating history

  • Identify existing & potential threats

  • Evaluate and rank risks

  • Identify and implement measures to address risks

  • Measure IM program performance, monitor results, and evaluate effectiveness

  • Periodically assess and improve the IM program

  • Report performance results to PHMSA and, where applicable, also to States

The DIMP Inspection Forms as well as other resources to support operators in implementing their IM programs are available on the DIMP Resources pages and through PHMSA's Pipeline Safety website. In addition, PHMSA has developed and continues to enhance guidance to help the public and the affected industry understand the requirements of the distribution IM regulations in the form of FAQs.