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Mechanical Fitting Failure Data from Gas Distribution Operators

Mechanical Fitting Failure Data from Gas Distribution Operators

Starting in 2011, PHMSA began collecting Mechanical Fitting Failure (MFF) reports on form PHMSA F-7100.1-2. In the Gas Pipeline Regulatory Reform rule (PHMSA 2018-0046-0063), PHMSA ended the MFF information collection to ease regulatory burdens on the construction, maintenance, and operation of gas distribution systems without adversely affecting safety. The effective date of the rule was March 21, 2021. PHMSA understands from analyzing MFF report forms received over the last decade that the purposes of this reporting requirement have been realized: PHMSA's analysis of data from MFF reports confirmed its expectations regarding MFF characteristics and causes, and pipeline operators have become much more sensitive to MFFs. While individual MFF reports are no longer required, the Gas Distribution Annual Report form PHMSA F-7100.1-1 will include a count of mechanical joint failures resulting in a hazardous leak starting with calendar year 2021 reports. Title 49 of the Code of Federal Regulations (49 CFR Parts 191, 192) required gas distribution pipeline operators to submit reports on an annual basis of all hazardous leaks that involve a mechanical fitting (DOT Form PHMSA F-7100.1-2). The CFR defines a hazardous leak, as well as criteria for submitting reports to the Office of Pipeline Safety. The following kinds of information were collected:

  • Key Report information
  • Date and Location information
  • Type of Mechanical Fitting Involved information
  • Apparent Cause of Leak information
  • Manufacturer information

The reports were used for identifying long- and short-term trends at the national, state and operator-specific levels. The frequency, causes, and fittings involved provided insight into the safety metrics currently used by PHMSA, state partners, and other pipeline safety stakeholders, including the pipeline industry and general public. PHMSA also uses the data for inspection planning and risk assessment.

Mechanical Fitting Failure Reporting (MFFR) Requirements

Pipeline System Type Hazardous Leak Definition MFFR Criteria and Requirements Submission Requirements for Written Reports
Natural Gas Distribution 49 CFR 192.1001 49 CFR 192.1009 49 CFR 191.12

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Last updated: Tuesday, April 20, 2021