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Gas Distribution Integrity Management Program: Performance Measures

Protecting America's Safety

Gas distribution pipeline operators are required to submit performance measure reports annually on their integrity management (IM) programs and on their pipeline infrastructure. PHMSA and State Pipeline Safety Programs use these reports, which are due on March 15 for the previous calendar year, to monitor and report on industry progress in meeting the requirements of the gas distribution IM regulations, and to respond to inquiries about both PHMSA's and individual State's oversight programs.

The distribution IM performance measure reports have been required since 2010, and these measures provide key information pertaining to operators' IM programs, including the total number of leaks either eliminated or repaired by cause, the number of hazardous leaks eliminated or repaired by cause, the number of excavation damages, the number of excavation tickets (based on One-Call notifications), the total number of Emergency Flow Valves (EFV's) installed on residential services, and the estimated number of EFV's existing in distribution systems at the end of the year.

You can see progress being made under the distribution IM regulations - for the entire nation, one of PHMSA's OPS (Office of Pipeline Safety) regions or an individual state - at the links below. Important definitions are included at the bottom of this page.

Leaks/Incidents shows the new Distribution IM data collected beginning in 2010 along with the historical leak data collected since 2005. The historical data consists of the total number of leaks which were repaired or otherwise eliminated, whereas the new Distribution IM data being collected includes this same leak count while also breaking out separately those leaks defined as hazardous. Additionally, beginning in 2010, data pertaining to Excavation Damage and Emergency Flow Valves (EFV's) is also being collected. Gas distribution incidents by-year and by-cause since 2005 are also shown. Incident causes are grouped as follows:

  • ALL OTHER CAUSES - the number of incidents by year whose cause is currently unknown, or where investigation into the cause has been exhausted and the final judgment as to the cause remains unknown, or where a cause has been determined which does not fit into any of the other cause categories shown.
  • CORROSION - the number of incidents by year caused by galvanic, atmospheric, stray current, microbiological, or other corrosive action.
  • EXCAVATION DAMAGE - the number of incidents by year resulting directly from excavation damage by operator's personnel (oftentimes referred to as "first party" excavation damage), by the operator's contractor (oftentimes referred to as "second party" excavation damage), or by people or contractors not associated with the operator (oftentimes referred to as "third party" excavation damage). This cause type also includes those incidents determined to have resulted from previous damage due to excavation activity.
  • INCORRECT OPERATION - the number of incidents by year caused by operating, maintenance, repair, or other errors by facility personnel, including but not limited to improper valve selection or operation, inadvertent overpressurization, or improper selection or installation of equipment.
  • MATERIAL/WELD/EQUIP FAILURE - the number of incidents by year in main or service pipe, or in welds, joints, or connections joining main pipe or service pipe due to faulty manufacturing procedures; defects resulting from poor construction, installation, or fabrication practices; and in-service stresses such as vibration, fatigue, and environmental cracking. Also included are incidents resulting from equipment failures such as: malfunction of control/relief equipment (valves, regulators, or other instrumentation); failures of the body of equipment, vessel plate, or other material; and all other equipment-related failures.
  • NATURAL FORCE DAMAGE - the number of incidents by year resulting from earth movement, earthquakes, landslides, subsidence, lightning, heavy rains/floods, washouts, flotation, mudslides, scouring, temperature, frost heave, frozen components, high winds, or similar natural causes.
  • OTHER OUTSIDE FORCE DAMAGE - the number of incidents by year caused by non-excavation-related outside forces, such as nearby industrial, man-made, or other fire or explosion; damage by vehicles or other equipment; failures due to mechanical damage; and, intentional damage including vandalism and terrorism.

Mechanical Fitting Failures shows data from gas distribution operators for failures of mechanical fittings. Data collected includes the failure cause, the location of the fitting in the pipeline system, the general type of fitting involved, and the specific type of fitting involved. 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. Once data collection began in 2011, mechanical fittings have been involved in about 5.5% of the hazardous leaks eliminated or repaired. See Mechanical Fitting Failure Reports available to the public. PHMSA performs analysis of mechanical joint failures data annually, and the current Data Analysis Procedure/Report is available to the public.

Gas Distribution Pipeline Materials shows the various pipe materials used in gas distribution systems. For each State, you can see the amount and percentage of gas distribution mains installed before 1960. The pipe material and pre-1960 mileage can be viewed for any year from 2010 forward. For additional information about aging pipeline infrastructure, see PHMSA's Pipeline Replacement Updates website.


EFV – An Excess Flow Valve (EFV) is a self-actuating valve that automatically closes when gas flow exceeds a predetermined rate.

Excavation Damages per 1000 Excavation Tickets – For the purposes of this IM performance measure, "excavation damage" does not necessarily need to result in a release of gas, and includes any impact that results in the need to repair or replace an underground facility due to a weakening, or the partial or complete destruction, of the facility, including, but not limited to, the protective coating, lateral support, cathodic protection or the housing for the line, device, or facility.

Excavation Ticket – Receipt of information by the Gas Distribution operator from the One-Call Center indicating planned excavation by third parties for which marking of buried pipelines by the operator may be required.

Hazardous Leak – A leak that represents an existing or probable hazard to persons or property and requires immediate repair or continuous action until the conditions are no longer hazardous.

Incident - An Incident involves a release of gas from a pipeline and:

  • A death, or personal injury necessitating in-patient hospitalization; or
  • Estimated property damage of the operator or others, or both, of $50,000 or more (cost of gas lost included prior to 2011; cost of gas lost excluded for 2011 and beyond); or
  • Unintentional estimated gas loss of three million cubic feet or more (for 2011 and beyond); or
  • An event that is significant, in the judgment of the operator, even though it did not meet the criteria above.

Leak - An unintentional escape of gas from the pipeline. A non-hazardous release that can be eliminated by lubrication, adjustment, or tightening, is not a leak.

Mechanical Fitting – A mechanical device used to connect sections of pipe. The term "Mechanical Fitting" applies only to: a) Stab Type fittings; b) Nut Follower Type fittings; c) Bolted Type fittings; or, d) Other Compression Type fittings.