Gas Distribution Integrity Management Program: FAQs


These Frequently Asked Questions (FAQs) are intended to clarify, explain, and promote better understanding of the distribution pipeline integrity management rules. These FAQs are not substantive rules and do not create rights, assign duties, or impose new obligations not outlined in the existing integrity management regulations and standards. Requests for informal interpretations regarding the applicability of one or more of the pipeline integrity management rules to a specific situation may be submitted to PHMSA in accordance with 49 C.F.R. § 190.11.

The State-Federal DIMP Implementation Team was created to support improvements in the integrity of the Nation’s gas distribution pipeline systems through development of inspection methods and guidance for evaluation of an Operator’s Distribution Integrity Management Program. Some material presented on this website was created by the team through a consensus process. States will implement the DIMP rule under their individual state statutory authority in accordance with the applicable certification under 49 U.S.C. 60105 of this title or agreement under section 60106. States may establish their own procedures, inspection forms, and guidance in implementing the DIMP rule. Since State authority and regulatory structures differ, operators should contact the regulatory authority exercising jurisdiction over the their distribution pipeline for more information.

Here you will find a listing of the most frequently asked questions (FAQs) related to the final rule.
You may:

  • view or download the entire set of FAQs in pdf format,
  • view or download the FAQs added/revised in the most recent FAQ revision,
  • browse the complete listing of FAQs below, or
  • browse a specific category from the following list.

A. Excess Flow Valve Requirements  
B. General Distribution Integrity Management Program Questions
C. Subpart P – Gas Distribution Pipeline Integrity Management
C.1 §192.1001
C.2 §192.1003
C.3 §192.1005
C.4 §192.1007
C.5 §192.1009
C.6 §192.1011
C.7 §192.1013
C.8 §192.1015

A. Excess Flow Valve Requirements

The Integrity Management Program for Gas Distribution Pipelines Final Rule included a revision to 49 CFR Part 192.383 Excess Flow Valve Installation which mandated the installation of excess flow valves (EFV) in certain new and replaced residential service lines.

A.1 Must an operator install an EFV in branch (split) service lines serving single-family residences?

No. Operators are required to install EFVs in new or replaced service lines serving single-family residences. A service line serving a single-family residence means a gas service line that begins at the fitting that connects the service line to the main and serves only one single-family residence.

Operators are not required, but may choose to install EFVs in other applications as part of their risk mitigation strategy.

Revision: 8/2/10
A.2 Must operators retrofit excess flow valves into existing service lines?

Operators are only required to install EFVs where single family residential service lines are newly installed or are replaced for other reasons. The rule defines “replaced” as where the fitting that connects the service line to the main is replaced or the piping that is connected to this fitting is replaced. Replacement of other portions of a service line (e.g., near the meter) would not trigger the requirement to install an EFV.

Revision: 8/2/10
A.3 Will excess flow valves provide protection for gas line breaks on customer piping inside a residence?

EFVs required by this regulation are not designed or intended to protect against breaks or leaks on customer piping inside a home. EFVs are intended to cut off the supply of gas to the downstream service line in the event of major damage (e.g., a line severed by excavation damage).

Revision: 8/2/10
A.4 Where must the EFV be installed on a service line?

An operator is required to locate an excess flow valve as near as practical to the fitting connecting the service line to its source of gas supply. Examples of acceptable locations include installing an EFV that is built into the service tee, installing a short section of pipe between the service tee and the EFV to allow for the pipeline to be squeezed off upstream of the EFV, and installing an EFV out from under pavement to facilitate future access. Operators may use reasonable judgment in determining the most appropriate location for an EFV.

Revision: 8/2/10
A.5 Will an operator have to notify other customer classifications of the availability of excess flow valves?

No. The notification requirement was repealed.

Revision: 8/2/10
A.6 Since installation of EFVs is mandated for all new and replaced service lines serving single-family residences where EFVs are feasible, why do operators still need to report them?

PHMSA is required by the Pipeline Inspection, Protection, Enforcement, and Safety Act of 2006 (PIPES) to collect this data.

Revision: 8/2/10
A.7 Does the operator report the number of EFVs installed per year or the total number of EFVs installed on an operator’s system on the Annual Report form? Does the number include EFVs installed on services other than single-family residences?

Operators are to report the total number of EFVs installed in the system on service lines serving single-family residences and the estimated number of EFVs in their system at the end Of the year. Both metrics are reported on the Annual Report form in Part E – Excess Flow Valve (EFV) Data. Operators may, but are not required, include EFVs installed on branched services serving single-family residences in the total. PHMSA is revised the Annual Report form for the 2010 calendar year to accommodate this information.

Revision: 2/9/11
A.8 The regulation exempts the installation of EFVs on services which do not operate at a pressure of 10 psig or greater throughout the year. Can you give examples of types of documentation that would be acceptable in demonstrating this issue?

Two possible methods to demonstrate that services operate at a pressure less than 10 PSIG include; (1) distribution system design documents, validated with actual pressure readings, which show that the main and therefore the associated services are designed to operate below 10 PSIG, or (2) actual pressure recordings or readings on all feeds which are upstream of the service(s) which are less than 10 psig.

Revision: 8/2/10

B. General Distribution Integrity Management Program Questions

B.1 DIMP Fundamentals

B.1.1 Why did PHMSA mandate integrity management requirements for distribution pipeline systems?

PHMSA’s regulations in part 192 have contributed to producing an admirable safety record. Nevertheless, incidents continue to occur, some of which involve significant consequences, including death and injury. It is not possible to significantly reduce high consequence pipeline incidents without reducing the likelihood of their occurrence on distribution pipelines. PHMSA used an integrity management approach similar to that used for transmission pipelines, with appropriate modification to reflect the different nature of distribution pipelines, to accomplish this safety improvement. These incidents often involve unique circumstances or characteristics of a particular pipeline system/ segment or its operation.

The Pipeline Integrity, Protection, Enforcement, and Safety Act of 2006 (PIPES) mandated that PHMSA prescribe minimum standards for integrity management programs for distribution pipelines. The law provided for PHMSA to require operators of distribution pipelines to continually identify and assess risks on their distribution lines, to remediate conditions that present a potential threat to pipeline integrity, and to monitor program effectiveness. Instead of imposing additional prescriptive requirements for integrity management, PHMSA concluded that a requirement for operator-specific programs to manage pipeline system integrity would be more effective given the diversity in distribution systems and the threats to which they may be exposed. Instead of imposing additional prescriptive requirements for integrity management, PHMSA concluded that a requirement for operator-specific programs to manage pipeline system integrity would be more effective.

Revision: 8/2/10
B.1.2 Why don’t distribution integrity management requirements focus on high consequence areas?

The integrity management requirements for transmission pipelines are focused on portions of the pipeline where significant consequences could result if an incident occurs — so-called “high consequence areas”. Transmission pipelines often traverse rural areas. This approach requires safety-improvement efforts to be focused on areas where consequences of an event would be more significant, in areas with greater human density, or more sensitive environment. Distribution pipelines are largely in developed, more populated areas, since they exist to deliver gas to those populations. As the population is in close proximity to much of these distribution systems, the consequences of an incident are similar throughout. For distribution pipelines, PHMSA concluded it is more appropriate that operators consider their entire pipelines under their integrity management programs.

Revision: 8/2/10
B.1.3 Why aren’t distribution pipeline operators required to physically inspect their pipelines as are operators of other types of pipelines?

The assessment techniques used on hazardous liquid and gas transmission pipelines (e.g., in-line inspection, pressure testing, direct assessment) are not transferable to distribution pipe. Additionally, distribution pipelines are not subject to the same pressures as transmission pipelines and thus tend to leak rather than rupture. It is important that distribution integrity management programs be focused on identifying the conditions that can cause leaks and addressing them before the failures occur and on managing leaks effectively when and if they do occur.

Revision: 8/2/10
B.1.4 Have State Agencies and PHMSA communicated with operators about Distribution Integrity? What has been discussed?

States periodically host PHMSA Training and Qualifications (TQ) pipeline safety seminars for operators including those of municipal, master meters, and small LPG systems. The seminars included updates regarding proposed rules and recent final rulemakings. Communications about DIMP covered information such as the anticipated final rule date, GPTC guidance development, the purpose of the regulation, and the proposed requirements for the rule. PHMSA's Regional offices also hold safety seminars which cover new and proposed rules, current initiatives, and advisory bulletins. PHMSA and some States have and continue to speak at national and statewide operator association meetings as well as both statewide and local emergency assistance meetings.

In 2007, prior to the DIMP Notice of Proposed Rulemaking PHMSA and the States, through NAPSR, created the DIMP State-Federal Team. PHMSA and the States have been working together to advance a consistent understanding of the DIMP. We have worked jointly to identify frequently asked questions, write responses and to develop inspection forms and guidance. Our joint efforts promote more uniform and knowledgeable inspections. Additionally, PHMSA’s TQ organization is working to prepare and provide timely training to state and federal pipeline safety inspectors. The group continues to meet and work together through the implementation phase.

Revision: 8/2/10
B.2 State and Federal Enforcement

B.2.1 How does PHMSA foresee this rule being enforced for compliance?

Inspectors will review the IM plan for quality and completeness and ensure that operators are doing what their plan says; and then inspect to see if their plan is effective. The procedures and records will be reviewed to verify that the operator performed them as written and in compliance with required dates. Enforcement will be consistent with current practice by the jurisdictional agencies.

Revision: 8/2/10
B.2.2 Will operators be compared against other operators or national leak or safety data?

PHMSA recognizes that operators need to develop a DIMP plan appropriate for the applicable threats, the operating characteristics of their specific distribution delivery system, and the customers that they serve. PHMSA and State partners intend to focus on each individual operator’s performance trends.

Revision: 8/2/10
B.3 GPTC Guidance

B.3.1 Must an operator follow the Gas Piping Technology Committee (GPTC) DIMP guidelines?

No. The GPTC DIMP guidelines provide options which operators can use in implementing the high-level requirements of the rule. The GPTC DIMP guidelines are not incorporated into the rule, and thus are not regulatory requirements. Operators may use other approaches to meet the high-level requirements of the regulation as well, but in doing so they should be prepared to demonstrate to their regulators that their actions meet the rule requirements. PHMSA, State pipeline safety regulators and industry all participated in the development of the GPTC guidelines and have confidence that operators who use them in their programs will comply with the requirements of the rule.

Revision: 8/2/10
B.3.2 How will the GPTC guidance be used by regulators?

The GPTC Guide provides operators with valuable, consensus written guidance that can assist them in preparing their DIMP plan. The GPTC Guide is not regulation. An operator needs to follow the procedures they include in their plan. If their plan references the GPTC guidance, the regulator may verify that the operator has implemented the referenced guidance as written. However, as referenced in B.3.1 above, an operator may choose to use practices other than those in the Guide to meet compliance. The inspection is based on the regulation, not on GPTC guidance.

Revision: 8/2/10

B.4.1 What is SHRIMP?

SHRIMP (Simple, Handy, Risk-based Integrity Management Plan) is a software application designed to assist operators in developing plans to manage the integrity of their distribution piping. It is geared toward the needs of small utilities that lack in-house engineering and/or risk management expertise. The American Public Gas Association (APGA) Security and Integrity Foundation (SIF) received funding from PHMSA for development. Contact APGA or the SIF for information or questions pertaining to SHRIMP.

Revision: 8/2/10
B.4.2 Is there a threshold size of an operator’s distribution system above which the SHRIMP tool should not be used?

SHRIMP was designed to facilitate development of a distribution integrity management plan for smaller distribution systems that are not overly complex. While there is no system size or level of complexity for which use of SHRIMP is excluded, an operator must develop a plan that demonstrates to its oversight agency it has used reasonably available information to develop knowledge, identify threats, and determine how to manage system risks. Ongoing analysis of SHRIMP for larger, more complex systems indicates that these operators will very likely need to significantly expand upon a SHRIMP-generated plan to demonstrate it has used reasonably available information to understand and determine how to manage system risks. These findings are being incorporated into inspection guidance.

Revision: 11/10/10
B.4.3 Will my plan be in compliance if I use SHRIMP?

The American Public Gas Association’s (APGA) Security and Integrity Foundation (SIF) developed the Simple Handy Risk based Integrity Management Plan (SHRIMP) to assist small operators in creating their written DIMP plan. Using SHRIMP does not necessarily mean that an operator will be in compliance with DIMP requirements. SHRIMP contains generic procedures. An operator's plan needs to reflect their own procedures, information sources, and practices. The APGA SIF is identifying areas where a SHRIMP user may need to enhance or modify the plan generated by this application to be in compliance with the pipeline safety regulations. Refer to APGA SIF website for the latest information.

Revision: 7/15/11

C. Subpart P – Gas Distribution Pipeline Integrity Management

C.1 §192.1001 What definitions apply to this subpart?

C.1.1 What was used as a basis for defining “hazardous leaks”?

The definition for hazardous leaks was drawn from the Gas Pipeline Technology Committee’s (GPTC), Guide for Gas Transmission and Distribution Piping Systems (The Guide) in Appendix G-192-11, Section 5.5 Leak grades. GPTC ANSI Z380 is an accredited American National Standards Institute (ANSI) standards committee that develops and publishes The Guide to assist natural gas pipeline operators in complying with Part 192. PHMSA’s Office of Pipeline Safety (OPS) is represented on this committee. Many operators now use the guidelines to classify leaks.

Revision: 8/2/10
C.1.2 How was the definition “excavation damage” developed?

PHMSA’s definition for excavation damage closely matches the definition used in the Common Ground Alliance’s (CGA) Damage Information Reporting Tool (DIRT). CGA is a national group involving operators of all types of underground facilities, as well as representatives of excavators and others who play an important part in preventing damage to underground facilities. PHMSA has omitted the phrase ‘‘of exposure’’ used in the DIRT definition, since this refers to damage from causes other than excavation (e.g., washout).

Revision: 8/2/10
C.2 §192.1003 What do the regulations in this subpart cover?

C.2.1 Must peak shaving and LNG facilities connected to our distribution pipeline system be considered in our DIMP?

A DIMP plan must include all parts of a gas distribution pipeline subject to Part 192. Liquefied petroleum gas (LPG) facilities are regulated under Part 192. Where an LPG peak shaving facility is part of an operator’s distribution pipeline, it must be included in its DIMP plan.

LNG facilities are regulated under Part 193 and therefore are not required to be included in a DIMP plan. However, PHMSA encourages operators to manage the risk from all of their facilities, and operators may elect to include LNG plants connected to their distribution pipelines in their DIMP plans as a means of doing so.

Revision: 8/24/11
C.3 §192.1005 What must a gas distribution operator (other than a master meter or small LPG operator) do to implement this subpart?

C.3.1 If an operator has both natural gas and LPG systems, must it have two separate DIMP plans or may it have a single plan?

The operator has an option. An operator may choose to have a single DIMP plan, but it must address the requirements for both types of systems. The plan must take into account the different threats associated with the different products. Or an operator may choose to have separate DIMP plans for the natural gas and for the LPG system.

Revision: 8/2/10
C.3.2 Must an operator have one DIMP plan covering all of its systems or could it have separate plans for different systems or service areas?

An operator may have one master plan or separate plans, so long as its entire service area is covered. However, data from multiple plans is required to be consolidated for annual reporting purposes by state.

Revision: 8/2/10
C.3.3 Will companies operating in several states need to develop individual DIMP plans for each state?

Multi-state operators may have one or more plans but must be able to filter by state their risk ranking, measures to reduce risk, performance measures and baselines, and other related data and information. The operator must address any additional requirements for each state since individual states may have the authority to impose additional requirements on intrastate lines the state regulates.

Revision: 5/1/12
C.3.4 What is the relationship between an operations & maintenance manual and a DIMP plan?

An O&M manual contains written procedures describing how operators conduct operations and maintenance activities on their system in accordance with Federal and State pipeline safety regulations. The activities address various threats to a pipeline’s integrity. A DIMP plan is a written integrity management plan which describes the analysis of the operator’s system, provides a relative risk analysis based on threats to the system, and prescribes additional or accelerated actions as needed to address risks identified in the plan.

An operator may find it convenient to incorporate additional or accelerated actions, as determined to be necessary under its DIMP plan, into its O&M manual. As the operator evaluates the effectiveness of these actions, it may identify a need to modify those actions, potentially requiring additional modifications to its O&M plan. Note that States may require a revision history, a record of modifications to the O & M manual.

Revision: 8/2/10
C.3.5 Is there a deadline by which operators must satisfy these requirements?

Yes, by no later than August 2, 2011, operators of gas distribution pipelines, including master meter or small LPG operators, must develop and implement an integrity management program that includes a written integrity management plan. PHMSA recognizes that implementing IM plans involves learning leading to improvement and expects that programs will evolve over time as experience is gained. However, the program developed by August 2, 2011, must address all of the required plan elements.

Revision: 8/2/10
C.3.6 How does the new DIMP rule impact operators of gas piping systems on military bases, Federal Government, or Indian Tribal Government land?

PHMSA does not regulate pipeline systems owned and operated by the Military, Federal Government, or an Indian Tribal Government. A "person" is defined in Section 192.3 of the pipeline safety regulations as "any individual, firm, joint venture, partnership, corporation association, State, municipality, cooperative association, or joint stock association, and including any trustee, receiver, assignee, or personal representative thereof." The definition of "person" does not include the "Federal Government", "Military" or "Indian Tribal Governments". Gas pipeline systems owned and operated by the Military, Federal Government or Indian Tribal Governments are exempt from compliance with the pipeline safety regulations.

However, if the system is owned and/or operated by a private entity, such as a contractor, then it must comply with the regulations under 49 C.F.R. 192. Therefore the DIMP rule also impacts gas systems on military bases, land owned by the Federal Government, or on land owned by Indian Tribal Governments if the system is owned or operated by private entities.

Revision: 11/10/10
C.3.7 Are operators required to include “farm taps” in their distribution integrity management plan?

In the past, distribution, gathering, and transmission operators connected landowners directly to transmission and gathering pipelines often in exchange for the right to install the pipeline across a landowner’s property. This connection to the gas pipeline is commonly referred to as a “farm tap”. Although new farm taps are not installed nearly as frequently as they were in the past, “farm taps” are very common. The vast majority of “farm taps” meet the definition of a distribution line given that they do not meet the criteria to be classified as a gathering line or a transmission line.

The “farm tap” is pipeline upstream of the outlet of the customer meter or connection to the customer meter, whichever is further downstream, and is responsibility of the operator. The pipeline downstream of this point is the responsibility of the customer. Some States require the operator to maintain certain portions of customer owned pipeline. The pipeline maintained by the operator must be in compliance with 49 Part 192.

Operators of distribution, gathering, and transmission lines with “farm taps” must have a distribution integrity management program meeting the requirements of Subpart P for this distribution pipeline. The DIMP plan is not required to include the customer-owned pipeline (unless required otherwise by State law). The operator having responsibility for operations and maintenance activities for the facility is responsible for developing and implementing the DIMP plan. For additional discussion see PHMSA’s interpretation dated April 19, 2011.

Revision: 8/2/10
C.3.8 What do operators need to have implemented by August 2, 2011?

By August 2, 2011, operators of gas distribution systems (other than a master meter or small LPG operator) must have developed and implemented an integrity management program that includes a written integrity management plan. The plan must include the operator’s procedures used to develop the seven elements listed in § 192.1007(a)-(g) At a minimum, an operator must have taken the following actions:

  1. Developed and demonstrated an understanding of their system;
  2. Identified and considered threats to each gas distribution facility;
  3. Completed a risk evaluation and ranking of their distribution system;
  4. Developed criteria for deciding when risks require measures to reduce them;
  5. Determined the measures to reduce risk;
  6. Begun implementing the measures to reduce risk or have a plan to implement measures to reduce risk which includes an implementation schedule;
  7. Assessed the effectiveness of their leak management program and taken steps, if necessary, to correct deficiencies;
  8. Established a baseline measurement for each performance measure required by 192.1007(e)(1)(i)-(v);
  9. Developed performance measures to evaluate the effectiveness of measures to reduce risk, have a plan to collect the performance measure data, and begun collecting data to establish a baseline measurement;
  10. Determined the appropriate period for conducting DIMP program evaluations;
  11. Reported performance measures required by 192.1007(g) for calendar year 2010;
  12. Collected data as needed for mechanical fitting failures resulting in hazardous leaks beginning January 1, 2011; and
  13. Identified records requiring retention and have maintained them.

Revision: 3/10/11
C.3.9 Can PHMSA provide a generic DIMP plan that operators can use to develop their plan?

PHMSA has not developed a generic DIMP plan. Commercially developed DIMP tools are available. Any tool will need to be customized for each specific operator.

PHMSA has developed a template that can be used by Master Meter and small LPG operators subject to the requirements of §192.1015. That template can be found on the DIMP Resources page of the DIMP website.

Revision: 7/15/11
C.3.10 What are the requirements for distribution systems put in service after 8/2/2011?

At the time a new distribution system is put into service, an operator must have developed and implemented an integrity management program that includes a written integrity management plan as specified by 49 CFR 192.1007 or 192.1015(b).

Revision: 8/24/11
C.3.11 What are the requirements for distribution systems acquired after 8/2/2011?

Operators must have a DIMP plan in place before taking over the operation of an acquired pipeline system. For purposes of distribution integrity management, an operator acquiring an existing pipeline system would be expected to either use the existing plan after verifying its adequacy, or integrate the newly acquired system into their integrity management program.

The new operator inherits the risk mitigation measures implemented and planned for implementation from the original operator’s plan unless they justify alternative measures to reduce risk.

Revision: 8/24/11
C.4 §192.1007 What are the required elements of an integrity management plan?

C.4.1 What does PHMSA see as the most critical elements of the regulation?

All of the elements are critical. The plan must have written procedures for developing and implementing all the elements.

Revision: 8/2/10
C.4.2 Can the DIMP plan incorporate by reference the operator’s procedures from their other manuals or plans?

Yes, operators may reference and incorporate procedures from their operating and maintenance manual or other plans in their DIMP plan.

Revision: 7/15/11
C.4.a Knowledge

C.4.a.1 The rule requires that an operator know its system. Must an operator excavate simply to gather information about parts of its system where it may not now have complete knowledge?

No. Operators need to gather the information that they have reasonably available to develop an understanding of their pipeline systems. The data may currently reside in different locations or be the responsibility of different groups within the company. Part of this development includes identifying information that is not now known, but which is needed to develop an understanding of the characteristics of the pipeline and necessary to assess applicable threats and to analyze its risk.

Revision: 8/2/10
C.4.a.2 There are some characteristics about an operator’s system that may not be known during the development of the IM plan. What are PHMSA’s expectations for filling those voids?

Operators need to use opportunities that arise, such as the pipeline being excavated for operation, maintenance, or other reasons, to collect additional information needed to better understand their pipeline system. Operators are required to incorporate into their plan and implement procedures to gather this information when the opportunity exists. This information may or may not prompt a reevaluation of the plan, but at a minimum, will be considered for analysis during the next scheduled evaluation. Records need to be maintained and updated to reflect changes to the system. Over time, PHMSA expects that an operator’s understanding of its pipeline system and the quality of their risk analyses will improve.

If an operator’s records have been destroyed or are no longer available, the operator must collect sufficient information, perform appropriate tests, and create records or maps for the safer operation, maintenance, and emergency response of the system.

Revision: 8/2/10
C.4.a.3 Who qualifies as a “subject matter expert”?

Subject matter experts are simply people who have specific knowledge of topics and/or facilities under consideration. This includes the operator’s operations and maintenance personnel – the people who construct, inspect, maintain and oversee its distribution facilities day-to-day. For some operators, this may include contractor personnel that have performed construction or operation and maintenance activities for a long period of time or for unique and/or special circumstances. In some instances, an operator may want to involve subject matter experts beyond its employees. For example, if analysis shows that an operator is having difficulty minimizing the detrimental effects of stray currents, the operator may want to involve in its program an outside person with expertise or specialized knowledge in this area.

Revision: 8/2/10
C.4.a.4 What data will be required to be collected for new gas pipelines going in the ground?

The DIMP regulation prescribes two minimum data elements that must be captured and retained on any new distribution pipelines: the location where the new pipeline is installed and the material of which it is constructed. Pipeline, defined in §192.3, means all parts of those physical facilities through which gas moves in transportation, including pipe, valves, and other appurtenance attached to pipe, compressor units, metering stations, regulator stations, delivery stations, holders, and fabricated assemblies. Additionally, operators must collect data about new gas pipelines which will be needed to assess current and future threats and risks to the pipeline’s integrity. This includes information about the characteristics of the pipeline’s design, operations, and the environmental factors where the pipeline is installed.

In addition, an operator must also consider the data it needs to comply with the various record keeping requirements in Part 192 such as those for pipeline design, testing, construction, corrosion control, customer notification, uprating, surveying, patrolling, monitoring, inspection, operation, maintenance, emergencies, and operator qualification. The GPTC Guide, Appendix G-192-17, provides operators with guidance on explicit requirements for reports, inspections, tests, written procedures, records and similar actions. States may have additional requirements.

Revision: 8/2/10
C.4.a.5 What comprises "reasonably available" information?

PHMSA does not intend that operators expend excessive effort, review every record available in their archives, or explore every nuance about their pipelines. At the same time, PHMSA expects that operators will devote sufficient effort to develop as thorough an understanding of their pipelines as they can while using reasonable effort.

The availability of records will vary among operators. Some operators may retain records for many years and others only for the length of time required by Part 192. Some data is stored electronically and some is paper based. Additionally, some records are stored on-site and other records may be stored off-site, such as at regional offices or long term storage facilities. Any record which the operator can access is reasonably available. All records required by Parts 191 and 192 are reasonably available. Operators need to review all records that are relevant to the current condition of the pipe or have a significant impact on the integrity of the pipe. For example, a steel pipe may have been brought under adequate cathodic protection five years ago but was not under cathodic protection in prior years. Any records showing that the pipe was not under cathodic protection, is relevant to the current condition of the pipe.

Operators must identify additional information that is needed to fill gaps due to missing, inaccurate, or incomplete records and develop a plan to collect it. They may collect this information through their normal activities including those that go beyond those activities specified in Part 192. For example, missing facility location, material and condition data can be gained when the pipe is located and/or exposed.

Operators could involve maintenance personnel in their information collection activities, surveying them about unusual circumstances they have encountered in their activities and/or asking them to review resulting system descriptions and identify any information they believe is useful that is not already included.

Revision: 3/10/11
C.4.a.6 Must an operator’s plan include the sources used to demonstrate an understanding of its gas distribution system?

An operator needs to be able to demonstrate to regulators that they have an understanding of their gas distribution system developed using sources of information that are “reasonably available”. The plan should identify the information sources. Examples of sources that are reasonably available include documents, records, field notes, maps, historical procedures and design standards, bill of materials, procurement records and specifications, and information obtained from subject matter experts. These sources are used to identify the characteristics of the pipeline’s design, operations and environmental factors that are necessary to assess the applicable threats and risks to the distribution system. Operators also need to consider information gained from past design, operations, and maintenance. In order to verify that an operator has met this requirement, the inspector may ask the operator for information about the sources such as: the name of the documents, the time period covered by the documents, the document’s location and format (e.g. electronic, paper, or subject matter expert interview, etc.), the forms used to collect data, the fields on the forms, the instructions used to complete the forms, and a history of how this information collection changed over time.

Revision: 3/10/11
C.4.a.7 With the incorporation of ASTM D2513-09a for Polyethylene (PE) effective March 6, 2015, would the Ultraviolet (UV) exposure limits be retroactive? In other words, if pipe that is manufactured before the effective date meets the new UV exposure limits, would those limits apply or would it still fall under the old 2 year limit per ASTM D2513-99?

It depends when the PE pipe was put into use (i.e. installed) based on the code language in §192.59 (a) and considering that 49 CFR Subpart B is not a retroactive subpart. If the PE pipe was not put into use until on or after the effective date, and an operator can demonstrate it meets ASTM D2513-09a, the UV exposure limit (or more appropriately Outdoor Storage Stability) requirements in Section 4.10 of ASTM D2513-09a would apply even if the PE pipe was manufactured prior to the effective date. If the PE pipe was put into use prior to the effective date, the Outdoor Storage Stability limits in A1.5.7 of ASTM D2513-99 would apply.

Records are critical for determination of adequacy, with the onus on the operator, to demonstrate which version(s) the PE pipe was manufactured to. What constitutes adequate records would likely vary, but it could include purchasing orders or other records between the operator and manufacturer, certificates of conformance from the manufacturer, and potentially other documentation from an operators QA/QC program. Such records should be tied to the specific lot numbers and segments in question (i.e. general certificates of conformance from a manufacturer not tied to lot numbers would typically not suffice.) Ultimate determination of adequacy would be up to whichever entity regulates the operator. If an operator cannot properly demonstrate PE pipe manufactured prior to the effective date meets ASTM D2513-09a, it is reasonable for a regulator to determine that the more conservative limits in ASTM D2513-99 would apply.

Revision: 7/01/15
C.4.b Identify Threats

C.4.b.1 Must an operator use a computer-based risk analysis model?

No. Risk analysis is a process of understanding what factors affect the risk posed by a pipeline system and which are most important. For a complex system, use of a computer-based risk model may make this process easier, but the use of a computer based modeling system is not required. For a simple distribution pipeline system, it is possible to do a credible analysis that leads to an understanding of factors/areas that are important to risk without use of such a model. The GPTC guidelines include suggestions for simpler approaches.

Revision: 8/2/10
C.4.b.2 Must each of the 8 threats be considered for every pipeline type?

Yes, an operator’s DIMP plan must consider each of the 8 threats for the pipeline system. The eight threats categories are corrosion, natural forces, excavation damage, other outside force damage, material or welds, equipment failure, incorrect operations, and other concerns that could threaten the integrity of its pipeline. Some threats may not be relevant to all pipe types or all operators’ circumstances. Some threats may apply but are not obvious. For example, corrosion is not a threat to plastic facilities but could be a threat to tracer wires, transition fittings, or to short pieces of metal main or services in a plastic system. Material or weld failures could apply to plastic (the brittle failure issue and potential for faulty fusion joints, for instance). Excavation damage occurs regardless of the pipe material.

Revision: 2/9/11
C.4.b.3 The DIMP requirements include knowing the condition of facilities that are at risk for potential damage from external sources. Cross bores of gas lines in sewers have been reported at 2-3 per mile in high risk areas – predominately where trenchless installation methods were used for gas line installs and where sewers and gas lines are in the proximity of each other. Does the potential for cross bore of sewers resulting in gas lines intersecting with sewers need to be determined?

Yes, the threat of excavation damage includes consideration of potential or existing cross bore of sewers which have resulted in gas lines intersecting with sewers. Pursuant to § 192.1007(a)(2), the operator must consider information gained from past design, operations, and maintenance. If operators used trenchless technologies without taking measures to locate sewer laterals and other unmarked facilities during construction, there may be a risk that their facilities were installed through the foreign facility. If this excavation damage threat applies to the operator, they must evaluate its risk to their system. Depending on the results of the risk evaluation, they may need to identify and implement measures to reduce this risk to existing and future facilities.

Revision: 3/10/11
C.4.b.4 Are pipeline “overbuilds” a threat? Should the “other concerns” threat category contain pipeline overbuilds (building put over a pipeline)?

A pipeline “overbuild” occurs when an existing pipeline facility is enclosed within or a building is built on top of the pipeline. Pipeline overbuilds are an environmental factor to be considered in evaluating the degree of risk to a pipeline. A gas line under a building may be susceptible to failure due to the natural force of settlement. Overbuilds also preclude proper access for the performance of leakage surveys, which is considered a detection activity as a risk control measure. The consequences of failure where a pipeline overbuild has occurred may be high due to the potential for the migration of gas into the building. If an operator identifies that pipeline overbuilds have occurred and are a threat to the integrity of its pipeline, then the threat should be identified and evaluated within the “other concerns” threat category.

Revision: 7/15/11
C.4.b.5 We used leak causes which we have experienced in the past to identify threats. For example, washouts in our system have not caused leaks in the past so washouts were not identified as a threat. Should washouts be classified as a potential threat due to the possibility of coating damage?

Yes, since the operator experiences washouts, they need to include this specific threat in their risk evaluation. The DIMP rule requires operators to consider both actual and potential threats. Even though washouts have not caused leaks in the past, the fact that pipe is located in areas subject to washouts indicates the potential for leaks due to washouts. The potential for damage (or likelihood of failure) from washout is different for different types of materials. Unsupported or washed out cast iron is much more susceptible to failure than unsupported steel or plastic. The level of risk would also be influenced by the amount of force and the frequency of the force the pipe may experience due to washouts. The measure to reduce risk from washout may require pipe to be buried deep enough to maintain the depth of cover prescribed in Section 192.327 Cover.

Revision: 7/15/11
C.4.b.6 Since we have not experienced any issues with pre 1973 Aldyl "A” pipe in the past, we did not subdivide plastic pipe in our risk evaluation. It is a potential threat to us only because of other operators' experience. Should we have treated it as an applicable threat?

Yes. Susceptibility to premature brittle-like cracking of certain Aldyl “A” pipe, along with other vintages and manufacturer’s products, is a well-documented problem in the industry and the subject of the PHMSA Advisory Bulletin ADB-07-02 (72 FR 51301), Updated Notification of Susceptibility to Premature Brittle-Like Cracking of Older Plastic Pipe. This is a “threat” applicable to any Aldyl “A” pipe in service (under the general category of “material”), whether or not the threat has resulted in leakage to date. The operator needs to consider this as an applicable threat.

Revision: 8/24/11
C.4.b.7 Must I consider historical leak data after a section of pipeline has been replaced?

Operators must consider all reasonably available information to identify threats. Leaks are often caused by factors external to the pipe, including corrosive environments, stray currents, etc. Replacing pipe eliminates leaks but does not necessarily eliminate the causes of those leaks. Historical data can be important in evaluating the relative likelihood of leaks occurring on the replaced pipe, particularly if the replacement pipe is of similar material and vintage. Operators who do not consider historical leak data as part of their DIMP plan must be prepared to demonstrate to inspectors that the data is no longer relevant.

Revision: 8/24/11
C.4.b.8 We often replace a section of pipeline rather than repairing individually the leaks in that section. In this case, must we record the number and grade of leaks?

The number and severity of leaks can be important information in evaluating the risk posed by a pipeline in a given location. Operators should consider leak history in their threat evaluations and thus field records should include the number and grade of leaks in sections of pipe that are replaced. Operators who do not record this information must be prepared to explain why this missing data does not impact their risk analysis.

Revision: 8/24/11
C.4.b.9 We are experiencing problems in ranking potential threats since some of the low frequency events have not occurred on our systems, to date. We are concerned about mixing apples and oranges by assigning a frequency or probability to a threat that has not occurred and ranking it along with events that do have frequency. How should we account for low or no frequency threats in evaluating and ranking risks?

The DIMP rule requires operators to consider both existing and potential threats in its evaluation and ranking of risks for which risk reduction measures are identified and implemented. Potential threats include, but are not limited to, non-leak events such as near-misses, over-pressurization events, material and appurtenance failures, etc. Even though certain potential threats may not have caused system integrity issues in the past, the fact that known industry risks exist require that an operator account for the threat in its DIMP. An operator may not rely entirely on leak history for identifying potential and existing threats. Potential threats include “near-miss” and other non-leak, operational events. If an operator eliminates a potential threat from consideration, justification must be provided in the DIMP for its exclusion. Prior to exclusion of a potential threat, operators should perform analysis of the “Other” leak cause data to ensure the potential threat has not been experienced to date.

When an algorithm is used to calculate risk, the lowest non-zero value for the frequency or probability available could be used along with an appropriate consequence value. This would result in a low probability threat, being risk ranked appropriately, especially if the event could have high consequences and is of concern. In programs that do not utilize algorithms, Subject Matter Experts should be used to quantify the frequency or probability of the potential threat and then quantify the consequences of a failure to evaluate and rank risks.

Revision: 2/6/13
C.4.c Evaluate and Rank Risks

C.4.c.1 What are the key things an operator should be focusing on when developing an effective risk assessment methodology?

High-quality data is core to an effective risk assessment. The integrity management plan must contain procedures for how the operator evaluates and ranks risks. Operators need to have a plan to identify and define the data necessary for the analyses. Additionally, processes should be in place to provide for data accuracy, completeness, and consistency. They should have a procedure to validate data and improve future data collected.

Operators must consider the risks (likelihood as well as the consequences of a failure) that might result from each threat. A potential incident of relatively low likelihood which produces significant consequences may be a higher risk than an incident with somewhat greater likelihood which may not produce major consequences.

Revision: 8/2/10
C.4.c.2 From which date are operators required to collect data for their plan?

Operators should use the information they already have and start keeping additional data to develop their plan (e.g., assess the threats) as soon as possible. They need to assemble and evaluate enough data to be able to evaluate the risk. Useful and usable historical data is needed to identify threats and trends.

Revision: 8/2/10
C.4.c.3 How are newly identified threats to the system's integrity expected to be handled in an operator's DIMP plan?

A DIMP plan addresses system integrity issues which occur over time. DIMP should address system integrity issues through data analysis. However, newly identified issues may require immediate action. One example is if an operator starts experiencing problems with a new style of fitting. Another example is the discovery of a material previously unknown to be contained within the system that has been identified as highly susceptible to failure. These risks should be addressed immediately and added to the DIMP plan as soon as feasible. The operator's response is dependent on the severity and location of the threat. If an operator discovers a threat which needs immediate risk reduction measures, they should implement the necessary actions.

Revision: 7/15/11
C.4.c.4 How are newly identified threats to the system's integrity expected to be handled in an operator's DIMP plan?

A DIMP plan addresses system integrity issues which occur over time. DIMP should address system integrity issues through data analysis. However, newly identified issues may require immediate action. One example is if an operator starts experiencing problems with a new style of fitting. Another example is the discovery of a material previously unknown to be contained within the system that has been identified as highly susceptible to failure. These risks should be addressed immediately and added to the DIMP plan as soon as feasible. The operator's response is dependent on the severity and location of the threat. If an operator discovers a threat which needs immediate risk reduction measures, they should implement the necessary actions.

Revision: 7/15/11
C.4.c.5 Do multiple threats need to be considered for each facility grouping? Do all threats need to be in one relative risk ranking?

The DIMP rule does not prescribe a risk evaluation methodology. The operator may choose a methodology which considers multiple threats to each group of facilities but the rule does not require this. The rule does prescribe that the risk ranking must consider each applicable current and potential threat. An operator may choose to group facilities differently for each threat, in which case, all threats need not be considered for all groupings. The final evaluation “must determine the relative importance of each threat and estimate and rank the risks posed to its pipeline.”

Revision: 8/24/11
C.4.c.6 What is expected of multi-state operator in regards to a risk ranking?

Multi-state operators need to be able to filter the relative risk ranking of their entire system by each individual state, or they may have a separate relative risk ranking for each state. They also need to provide the measures they are taking to reduce risk by state or be able to filter the measures they are taking system-wide to those they are taking in each state.

Revision: 8/24/11
C.4.c.7 We plan to perform a risk ranking by state. Regardless of the outcome of the risk ranking, we will not decrease the historical level of expenditures in each state. However, a system wide risk ranking will be used to determine where expenditures beyond historical levels will be allocated. Does that meet the intent of the state by state risk ranking?

The operator sets the risk threshold, and determines where measures designed to reduce the risks of failure of its gas distribution pipeline are needed. The criteria should be the same for the entire system regardless of the state. Actions should be commensurate with risk. If the risk is viable, the operator must take some action to reduce it.

The intent of the state-by-state ranking is for State Pipeline Safety Programs to review the risks and measures to address them in the state for which they have jurisdictional authority. Since State regulators do not inspect systems in other states, they do not have firsthand knowledge of that portion of an operator's system. Some states may have additional regulatory requirements beyond DIMP.

Revision: 8/24/11
C.4.c.8 With the pending revisions to Part 192 to prohibit rework/regrind in plastic pipe, will there be an expectation that any systems/segments that include pre-code revision pipe with rework be considered a higher risk when ranking risks for DIMP versus systems/segments with no rework/regrind pipe?

Special consideration for higher risks may be warranted if the operator has knowledge that they installed pipe from a lot containing rework material with indications of contamination, uneven mixing or degradation of certain material properties such as dielectric breakdown, resistance to slow crack growth (SCG) and resistance to rapid crack propagation (RCP). Considerations to include in the analysis would include, but are not limited to the leak and incident history of the operator’s pipe, any specific batches or lot numbers that are known to be problematic, etc. However, pipe that might contain rework material need not be considered higher risk immediately absent some evidence of a problem (e.g., unsatisfactory material inspection results, poor performance in service, a tie to a proven batch of problematic material, etc.). Awareness of the presence of a lot containing rework material is the first step in gathering information and effectively monitoring any issues.

Any operator that knows they have a lot containing contaminated or improperly mixed rework material should consider the incorporation of a more stringent monitoring program into their DIMP. For example, O&M Procedures for compliance with §192.613 “Continuing Surveillance” and §192.617 “Investigation of Failures” should be modified, as necessary, to include rework material as a note or cause when analyzing incidents and failures for the purpose of determining the causes of the failure and minimizing the possibility of a recurrence. Field personnel should also be made aware of the issue of installed pipe from an identified problematic lot containing rework material and the identification of failure modes that may be caused by issues in the rework process or contamination (e.g., uneven mixing, evidence of contamination, or degradation of material properties such as dielectric breakdown, reduced resistance to slow crack growth (SCG), and reduced resistance to rapid crack propagation (RCP).) It is reasonable to expect that in most cases field personnel would only be able to detect defects that may be visual, such as evidence of contamination, uneven mixing, etc. In more extreme cases, operators should consider additional failure analysis to determine if other factors impacting material properties and overall integrity of the plastic pipe are present, and if the issues are systemic throughout a certain lot number or region where the pipe is installed. It is also reasonable to expect that depending on how long the pipe was in service, it could be very difficult to tie material property issues specifically to the rework process vs. impact from other operational or environmental issues that might have impacted the pipe over time.

If a lot containing rework material is identified as higher risk, an operator should take additional steps to minimize the risk. Additional monitoring and information gathering would be necessary to “quantify” the risk associated with a known batch of pipe with proven problems. Identifying the installation locations would be part of the information gathering exercises and support removal of the lot of material from the operator’s system if risk thresholds were exceeded.

Revision: 7/9/14
C.4.d Identify and Implement Measures to Address Risks

C.4.d.1 Must an operator implement additional or accelerated actions to reduce risk from its pipeline?

The DIMP rule is intended to improve safety performance. Improving performance may require operators to implement additional or accelerated actions to manage identified system risks, but in other instances such actions may not be required. Some operators have already implemented additional risk control and mitigation activities voluntarily. It is possible that these ongoing actions already adequately address the risks that are significant to some pipeline systems.

What the DIMP Rule does require is for operators to periodically consider potential improvements to their IM program. Operators must perform a risk analysis to understand the factors that are important to their risk and should compare the results of this analysis to the actions now being taken to assure pipeline safety. If gaps are identified (i.e., instances in which some factor important to risk is not now being adequately addressed) then appropriate risk control practices may need to be implemented. Operators also may find it appropriate to reduce some non-mandated actions now being taken (e.g., which address risks of lower importance) and to reallocate those resources to address higher priority risks. Operators must still comply with all the requirements of the regulations.

Revision: 8/2/10
C.4.d.2 How will small operators, with limited staff, be able to implement the requirements for risk analysis and selection of risk control measures?

The level of analysis required and risk control measures to be implemented are related to the complexity of an operator’s distribution pipeline system and the variability of threats across a system. Operators with small staffs typically operate smaller, simpler systems, so that the effort required to conduct risk analysis and to select risk control measures should be less than that required of operators of more-complex systems.

PHMSA published, “Guidance on Carrying Out Requirements in the Gas Distribution Integrity Management Rule Pipeline Safety: Integrity Management Program for Gas Distribution Pipelines,” to help large and small, master meter, and LPG operators implement the requirements of subpart P of Part 192. Guidance for large and small operators begins at section I and for master meter and LPG operators at section V of this document. The document is located on the PHMSA’s DIMP web site under DIMP Key Documents

The Gas Piping Technology Committee (GPTC) DIMP guidelines provide guidance on relatively-simple approaches to risk analysis. The American Public Gas Association (APGA) Security and Integrity Foundation, with partial funding from PHMSA, developed the Simple, Handy, Risk-Based, Integrity Management Plan (SHRIMP), a computer-based program that is intended to assist small operators in preparing a plan to meet rule requirements.

Revision: 8/2/10
C.4.d.3 If an operator already has a leak management program, does the operator have to implement a new program in response to this regulation?

Not necessarily. Operators may not need to implement new leak management programs. Rather, operators should review their current leak management program to assure that it is effective and when needed, adjust their program to comply with the regulation. Leak management is an important factor in managing the risks associated with distribution pipeline systems. PHMSA recognizes that distribution pipeline operators currently have leak management programs in place and that these programs are generally effective. For example, corrosion is a leading cause of distribution pipeline leaks, but corrosion is only the cause of four percent of reportable distribution incidents; PHMSA believes that effective leak management is a major reason for this performance – operators identify and address severe leaks before incidents occur.

Revision: 8/2/10
C.4.d.4 Why not simply require operators of gas distribution pipelines to replace old pipe?

The rule requires that operators analyze their pipeline systems to identify the hazards that affect them and evaluate the risks posed by each threat. Operators must determine and implement measures designed to reduce the risks from failure. Pipe replacement is certainly one action an operator could take to mitigate some risks to its system.

Simply because a pipeline is old, does not mean that it is a risk to public safety. Some types of older pipe operate safely and have not been involved in incidents. Meanwhile, some newer pipes, including particular kinds of plastic fittings, have proven problematic and have caused incidents. State regulators have occasionally required operators to implement pipe replacement programs, but these replacement programs have been targeted to specific problematic pipe based on the local circumstances facing particular operators. Operators already are required to initiate programs to recondition or phase out segments of pipelines determined to be in unsatisfactory condition. Threats such as excavation damage, which is the leading cause of distribution pipeline incidents, would not be addressed by a pipe replacement program. The rule requires gas operators to analyze the risk of their pipeline, given their unique circumstances, including the age of their pipeline system. Operators should use these risk analyses to identify actions to reduce risk, including the possibility of replacing selected pipe. Regulators may oversee an operator’s risk management decisions.

Revision: 8/2/10
C.4.d.5 What kind of issues should an operator focus on in addressing the threat of Excavation Damage as part of its DIMP Plan?

Excavation damage is the leading cause of “significant” pipeline incidents (causing injury or fatality). PHMSA published a document entitled, Damage Prevention Assistance Program (DPAP): Strengthening State Damage Prevention Programs. Building on the nine elements of effective damage prevention programs found in the Pipeline Inspection, Protection, Enforcement and Safety Act of 2006 (PIPES), this document provides guidance to stakeholders for strengthening state damage prevention programs. While not all of these nine elements are within the operator’s direct control, certain operators working with state regulators and other stakeholder groups have found ways to facilitate progress in addressing the nine elements.

Revision: 8/2/10
C.4.d. 6 In order to eliminate the need for a leak management program, how quickly would an operator need to repair all leaks?

The rule states that a leak management program is not needed if all leaks are repaired when found. All hazardous leaks must be repaired promptly. To eliminate the need for a leak management program, an operator would need to continue to work on each leak, hazardous and non hazardous, until it is eliminated as opposed to scheduling the repair or periodically monitoring the leak.

Revision: 8/2/10
C.4.d.7 Can the installation of excess flow valves be a method to mitigate risks?

Excess flow valves are one means to reduce the consequences of a potential incident when properly designed and installed. The valve automatically shuts off the flow of gas in a service line when the gas flow in the line exceeds the valve setting. The valve trips when there is severe damage to the pipeline, significantly increasing the gas flow rate. Such significant increases in gas flow rate are most often caused by excavation damage that ruptures the service line downstream of the valve. The risk of the excavation damage still exists. EFVs are an efficient means of reducing the consequences in densely populated areas, on services to public or difficult to evacuate buildings, or areas where operators cannot reach rapidly shut off the flow of gas in an emergency. The GPTC DIMP Guidance identifies the use of an EFV as a possible risk mitigation measure.

Revision: 7/15/11
C.4.d.8 What criteria should an operator use to identify when a measure to reduce risk is needed?

The operator must define the threshold level at which additional measures to reduce risk must be implemented. The operator must be able to justify the basis used for establishing the threshold level for each identified risk. It is not sufficient simply to re-state the decision without describing why it was made. Regulatory compliance inspections of an operator’s DIMP plan will include an evaluation of the operator’s selection of risk mitigation measures and will determine whether the appropriate additional measures have been implemented.

Revision: 7/15/11
C.4.d.9 Do all actions operators take to reduce risk need to be included in their DIMP plan?

An operator must include in its written DIMP plan all measures it selected to reduce risk from failure on those portions of its gas distribution pipeline that met its criteria for needing a measure to address the risk identified through their risk evaluation process. If an operator implemented risk reduction measures prior to the promulgation of the DIMP rule on piping that does not meet its criteria for needing additional action to reduce risk, the operator may include these other measures in its DIMP plan, however it will need to also include in the Plan methods to evaluate the effectiveness of these measures.

Revision: 7/15/11
C.4.d.10 We have heard that operators will be required to implement specific measures to reduce risk. Can you describe the required actions?

Operators determine which risk reduction measures they will implement. They are required to collect and analyze performance measure data to demonstrate that the measures to reduce risk are effective.

Revision: 7/15/11
C.4.d.11 How can an operator demonstrate that their leak management program is effective?

Operators need to evaluate the effectiveness of their leak management program through a self-audit program. The basic elements of a leak management program are:

  1. Locate the leaks in the distribution system – (your plan needs to describe your leakage detection procedures)
  2. Evaluate the actual or potential hazards associated with these leaks (your plan needs to describe your leak classification criteria)
  3. Act appropriately to mitigate these hazards (your plan needs to describe your leak repair or monitoring schedule)
  4. Keep records (of leak surveys, leaks, and self-audit data)
  5. Self-assess to determine if additional actions are necessary to keep people and property safe (The purpose of a periodic self-assessment is to determine if the leak management program is effective and, if necessary, to identify changes necessary to ensure that it is effective. Your plan needs to include how you perform your self assessment and the results of the self-assessment.)
An operator must either include the leak management program procedures in its DIMP plan or reference the procedures in your O&M.
Revision: 7/15/11
C.4.d.12 I am considering inserting a liner into an existing cast iron main. If I install a liner into an existing cast iron distribution main host pipe, can I consider the combination of the liner and the existing pipe as a new composite structure, or should I consider the liner as a repair method for the existing cast iron main? What considerations should I account for when installing a liner into an existing cast iron distribution main? Additionally, is a State waiver or PHMSA special permit needed when using a liner to prevent leakage from a host pipe?

PHMSA does not consider the insertion of a liner into a host pipe as a new “composite” structure. §192.489(b) allows for cast or ductile iron with localized graphitization to be sealed by internal sealing methods adequate to prevent or arrest any leakage. Operators using liners would still need to operate and maintain the host pipe in the context of Part 192 requirements.

A state waiver or PHMSA special permit is not needed when using the liners as non-structural liners to help prevent or arrest any leakage, as liners are a generally recognized repair technique. There may, however, still be long term integrity issues for both the liner and host pipe that an operator would need to consider that may require revisions or additions to construction, operation and maintenance, and/or emergency response plans and procedures. . The operator would still need to declare the host pipe material on the annual report. PHMSA understands that cured-in-place (CIP) pipe liners have been installed into existing metallic gas pipes liners to recondition cast iron host pipe, and PHMSA has amended the Gas Distribution Annual Report to include a data collection field for miles of reconditioned cast iron mains and number of services.

A state waiver or PHMSA special permit would likely be needed if the operator is intending to use the liner more as a structural liner to effectively replace the cast iron, unless the operator is using a material manufactured in accordance with a listed specification in Part 192 and meets other applicable requirements of Part 192. For instance, if using a structural composite type liner that is not currently recognized in Part 192 a state or PHMSA special permit would be needed. If using recognized materials such as polyethylene or polyamide plastic materials manufactured per a listed specification in Part 192, a state waiver or special permit would not be needed assuming the material can withstand the pressure and meet all other requirements in Part 192 including determination of MAOP. For either scenario, other considerations would also have to be addressed such as preventing external damage to the material during installation or while in service.

For additional guidance, PHMSA currently has two (2) research and development projects focusing on the engineering assessment of structural liners and their interaction with the host pipe as well as the long term performance of in-service liners.

ASTM F2207-06 (Reapproved 2013), titled “Standard Specification for Cured-in-Place Pipe Lining System for Rehabilitation of Metallic Gas Pipe”, covers requirements and methods of testing for materials, dimensions, hydrostatic burst strength, chemical resistance, adhesion strength and tensile strength properties for CIP pipe liners installed into existing metallic gas pipes. The CIP pipe liners covered by this specification are intended for use in pipelines transporting natural gas, petroleum fuels (propane-air and propane-butane vapor mixtures), and manufactured and mixed gases, where resistance to gas permeation, ground movement, internal corrosion, leaking joints, pinholes, and chemical attack are required. While the word composite is used throughout ASTM F2207-06, through its own definition composite is only the combination of the cured adhesive system, the elastomer skin, and the jacket comprising the liner. Elsewhere in ASTM F2207-06, it considers the host pipe separately from the composite liner system, and a key section on issues to consider is Section 1.2.1 regarding the need for the operator to maintain the structural integrity of the host pipe so that the liner does not become free standing.

Revision: 10/26/15
C.4.e Measure Performance, Monitor Results, and Evaluate Effectiveness

C.4.e.1 Why has PHMSA selected the performance measures that it has for periodic reporting?

Measuring performance periodically allows operators to determine whether actions being taken to address threats are effective, or whether different actions are needed. It is also important for PHMSA and the States to measure the safety improvement (i.e., performance) achieved by this new regulation. Ultimately, a decrease in the number and consequences of distribution pipeline incidents will be the true measure of success, but it will take many years of accumulating data to determine with confidence that there is a declining trend in incidents/consequences. PHMSA needs data that will be useful in a shorter time frame to show whether improvements are being realized or if further adjustments to requirements are needed.

PHMSA has concluded it would be most useful for operators to report four performance measures. PHMSA recognizes that there will be some variability in the criteria for these performance measures among operators. The performance measures are intended to measure individual operator, state, and national trends.

The total number of leaks eliminated or repaired by cause and the number of hazardous leaks eliminated or repaired by cause are two of the reportable performance measures. Leaks can lead to incidents and hazardous leaks represent the highest risk leaks. PHMSA and State partners expect effective integrity management programs to produce a reduction in the number of leaks. The total number of leaks scheduled for repair has historically been part of the Annual Report submitted by operators of distribution pipelines.

The other reportable performance measures are the number of excavation damages and the number of excavation tickets. Excavation damage is the leading cause of significant distribution pipeline incidents. The number of excavation tickets is an indicator of the total amount of excavation activity in an area. This data will be used to normalize the reported number of excavation damages in analyzing performance since excavation damages occur as an unintended consequence of digging. PHMSA and State partners would expect effective integrity management programs to produce a positive trend in the level of excavation damage per the number of damages per ticket (or per 1000 tickets) over time.

Revision: 8/2/10
C.4.e.2 Does every measure to address risk require a performance measure?

Each risk reduction measure or group of measures an operator identifies through their risk evaluation process needs to have a performance measure. Operators must establish a baseline for every performance measure. Operators must be prepared to explain why each performance measure was chosen and describe how the performance measure data is or will be collected.

Revision: 7/15/11
C.4.f Periodically Evaluation and Improvement

C.4.f.1 How often does an operator need to evaluate its program?

Operators must evaluate their program at a period appropriate for their system, but at an interval not exceeding five years. An operator should re-evaluate its IM program whenever new knowledge, new threats or other information would substantially alter the operator’s DIMP program. This could range from once each calendar year to less frequently, but must not exceed once every five years.

Revision: 8/2/10
C.4.f.2 What constitutes a periodic evaluation?

The operator’s procedure needs to describe the actions the operator will take during the program evaluation. It should include the following actions:

  • Description of the frequency of review based on the complexity of the system and changes in factors affecting the risk of failure, not to exceed 5 years
  • Verification of general information (e.g. contact information, form names, action schedules, etc.)
  • Incorporation of new system information
  • Re-evaluation of threats and risk
  • Review of the frequency of the measures to reduce risk, where applicable
  • Review of the effectiveness of the measures to reduce risk. This includes, at minimum, reviewing the results of the performance measure(s) for each measure taken to reduce risk.
  • Review of the measures implemented to reduce risk and refine/improve as needed (i.e. add new, modify existing, or eliminate if no longer needed)
  • Review of performance measures, their effectiveness, and if they are not still appropriate, refine/improve

Revision: 7/15/11
C.4.g Report Results

Performance Measures

C.4.g.1 When must operators start collecting and maintaining records with data needed for performance measures?

Reportable performance measures are to be submitted via the Gas Distribution Annual Report for Calendar Year 2010 which covers activities from January 1, 2010 thru December 31, 2010. The 2010 calendar year Annual Report is due by March 15, 2011.

Revision: 2/9/11
C.4.g.2 When are performance measures due on Annual Reports?

The reportable performance measures are to be submitted via the 2010 Gas Distribution Annual Report form which is due by March 15, 2011. An operator also must report this information to the state pipeline safety authority if a state exercises jurisdiction over the operator’s pipeline.

Mar. 15, 2011 – Operators use proposed revised Gas Distribution Annual Report form, PHMSA F 7100.1-1 (12-05). It contains fields for reportable performance measures for the 2010 calendar year. Mechanical fitting failures are not to be reported for calendar year 2010.

Mar. 15, 2012 - Annual Report for calendar year 2011 must contain the required data for reportable performance measures from January 1, 2011 thru December 31, 2011.

Revision: 2/9/11
C.4.g.3 Can PHMSA further define the number of excavation tickets on the new form?

The definition of an “excavation ticket” varies among state one-call programs. Requiring operators to track tickets in two ways— one matching their one-call program definition and one matching a common national definition, would entail considerable additional effort without commensurate benefit. PHMSA encourages operators to use the criteria currently in place with the State law and one-call center which determines when notifications should be made.

The total number of excavation tickets includes all receipts of information by the underground facility operator from the notification center. Operators may choose to include or not include receipts of information directly from excavators or others. An operator’s reporting criteria should remain consistent from year to year.

Revision: 8/2/10
C.4.g.4 For municipal operators or joint utility operators, should the number of excavation tickets include all excavation tickets or just those sent to the gas department?

The number of excavation tickets should only include a count of the receipts of information from the notification center to the gas pipeline underground facility operator.

Revision: 8/2/10
C.4.g.5 Are multiple tickets for a single job counted as a single excavation ticket?

Some state laws require excavators to call in additional requests for on-going jobs prior to the life of the first excavation request expiring. In reporting data these additional requests for excavation projects of extended duration may be counted since there is excavation work associated with those requests. However, operators do not need to change the criteria for counting excavation tickets for the purpose of reporting performance measures. If they currently count multiple tickets for a single job, they may continue that practice. The definition of “ticket” should remain consistent with State law and one-call center definition.

Revision: 8/2/10
C.4.g.6 What if the excavation damage occurs on an excavation with no ticket?

The occurrence must be reported in the number of excavation damages but not counted as an excavation ticket. The lack of a ticket likely means that damage prevention activities associated with one-call programs did not occur and that damage may thus have been more likely.

Revision: 8/2/10
C.4.g.7 We have a lot of steel risers which can be tightened to eliminate leaks. We have not reported these on Form 7100 in PART C - TOTAL LEAKS AND HAZARDOUS LEAKS ELIMINATED/REPAIRED DURING YEAR in the past. Are these leaks considered reportable leaks per DIMP, and should this threat be considered in a DIMP plan?

The operator needs to follow their procedures and report all leaks which upon discovery are determined to be hazardous even if the leak is subsequently eliminated or repaired by lubrication, adjustment, or tightening.

The Annual Report instructions do not allow for excluding hazardous leaks even if they can be eliminated or repaired by lubrication, adjustment, or tightening. The Annual Report instructions state the following:

  • a “leak” is defined as 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 [and thus not reported on the Annual Report]. (emphasis added)
49 CFR 192.1007(e)(1)(i) requires that operators report the number of hazardous leaks either eliminated or repaired as a DIMP performance measure (or the total number of leaks if all leaks are repaired when found). If an operator repairs all leaks when found rather than grading them, then all releases that can be eliminated by lubrication, adjustment, or tightening must be reported. In either case, this information is reported via Part C of the Annual Report.

The frequency of non-hazardous releases that are not reported could indicate a recurring problem (e.g., fittings issue, poor construction practices, human error) that should be considered in an operator’s DIMP program.

Revision: 8/24/11
C.5 §192.1009 What must an operator report when a mechanical fitting fails?

C.5.1 Why is PHMSA collecting data about mechanical fitting failures?

PHMSA has seen some regional issues with mechanical fittings. PHMSA plans to analyze the national data from the Annual Reports to develop better information about the types and causes of fitting failures. This information will be communicated to operators so that they can act appropriately.

Revision: 8/2/10
C.5.2 Do States already collect the type of information that is to be collected for mechanical fitting failures?

Not fully. Mechanical fitting failure information has been collected in Annual Reports and Incident Reports as a subset of the “material and weld”, “equipment”, and “other” failure sections. The information collected on the reportable incident form was limited to the type of joint and the cause of the failure, either construction or material defect and was only reported if the mechanical fitting failure resulted in a reportable incident. On the Annual Report, the mechanical fitting failures would be included in the count of “Leaks Eliminated/Repaired During Year”, categorized by threat. The information now being collected for mechanical fitting failures is more detailed but excludes instances that result in non-hazardous leaks. The incident report was updated on January 31, 2010. For a copy of the report, go to PHMSA’s web site at

Revision: 8/2/10
C.5.3 Should both steel and plastic mechanical fitting failures be reported? How about the different styles of plastic mechanical fittings? Do mechanical fitting failures in cast iron systems need to be reported?

All types of mechanical fitting failures should be included regardless of material. The objective of the data collection is to identify mechanical fittings which, based on a historical data, are susceptible to failure. The Advisory Bulletins, ADB-86-02 issued on February 26, 1986, and ADB-08-02 (73 FR 11695) issued on March 4, 2008, identified issues with mechanical fittings which could lead to failure. The bulletin advised operators to perform certain actions. Determining the apparent cause of these mechanical fitting failures is important to determine if and what type of additional actions may be needed if trends are identified. PHMSA intends for operators to report all types and all sizes of mechanical fitting failures which result in a hazardous leak. The failure can occur on a fitting connected to a pipe or a fitting that joins sections of pipe. Mechanical fittings include stab, nut follower, and bolt type fittings. The reporting requirements apply to failures in the bodies of mechanical fitting or failures in the joints between the fittings and pipe.

Operators are to report mechanical fitting failures as the result of any cause including excavation damage. Mechanical fittings are to be included regardless of the material they join. For example, include mechanical fittings which join steel to steel, steel to plastic, and plastic to plastic. Examples of the use of mechanical fittings may be found in the following applications: service tees, tapping tees, transition fittings, couplings, risers, sleeves, ells, “Ys”, and tees. Failures on fittings that are joined by solvent cement, adhesive, heat fusion, or welding are not to be reported as mechanical fitting failures.

PHMSA does not intend to collect information about failures of cast iron bell & spigot joints unless the leak resulted from a failure of a mechanical fitting used to repair or reinforce a joint.

Revision: 7/15/11
C.5.4 Since there is a new form for mechanical fitting failures which result in a hazardous leak, do these failures still need to be reported under Part C of the Annual Report?

Yes, operators need to include all mechanical fitting failures which result in hazardous leaks eliminated or repaired as part of the total leaks reported on the Annual Report in Part C - TOTAL LEAKS AND HAZARDOUS LEAKS ELIMINATED/REPAIRED DURING YEAR. Additionally, they must report detailed information about each mechanical fitting failure which results in a hazardous leak on a separate Gas Distribution Mechanical Fitting Failure Form (PHMSA F–7100.1–2).

PHMSA created the new Mechanical Fitting Failure Report form [PHMSA F 7100.1-2] to address the new annual reporting requirement established by DIMP for hazardous leaks on mechanical fittings. Operators may submit data at anytime and at any frequency throughout the year (preferred), or they may submit all mechanical fitting failure reports in one submission. Regardless of the method they select, the reports must be submitted by March 15, 2012 for failures which occurred in calendar year 2011. If an operator does not experience any mechanical fitting failure which results in hazardous leaks, they do not need to submit a Mechanical Fitting Failure Report form. The online system for the new Mechanical Fitting Failure Report form [PHMSA F 7100.1-2] is now in operation.

NOTE: Online submission via PHMSA Portal is required unless an alternative reporting method is granted by PHMSA. More information is available at PHMSA’s, Office of Pipeline Safety web site, Pipeline Safety Community, located at and click the “Online Data Entry” hyperlink listed in the first column.

Revision: 3/10/11
C.5.5 If aboveground mechanical fitting failures are hazardous but repaired do they need to be reported?

Yes, all mechanical fitting failures which are hazardous upon discovery must be reported. If a mechanical fitting failure results in a hazardous leak, regardless of how it is eliminated, report the failure on the annual report (Part C) and submit a mechanical fitting failure report.

Revision: 7/15/11
C.5.6 What are the expectations of operators in determining a cause for mechanical fitting failures which result in a hazardous leak?

Operators should follow their procedure required by 192.617, Investigation of failures, for analyzing failures, including the selection of samples of the failed facility or equipment for laboratory examination, where appropriate, for the purpose of determining the cause(s) of the failure and minimizing the possibility of a recurrence. Operators must try to determine the apparent cause of the leak. An operator may have experienced similar failures in the past and can readily determine the apparent cause. Hazardous leaks on mechanical fitting failures for which the apparent cause is not readily determined will require additional investigation commensurate with the level of risk (likelihood and consequences) of a failure of similar fittings.

Revision: 7/15/11
C.6 §192.1011 What records must an operator keep?

C.6.1 What records does an operator need to maintain to demonstrate compliance with Subpart P?

Pursuant to § 192.1011, an operator must maintain records to demonstrate compliance with the requirements of subpart P for at least ten years. The records must include copies of superseded integrity management plans developed under subpart P. To the extent that records demonstrate compliance with the DIMP Rule requirements, they are to be maintained by the operator such that they are readily retrievable, protected from damage, and secured sufficiently to prevent unauthorized use. The records include but are not limited to:

  • A written integrity management program
  • Knowledge of the system documents
  • Threat identification and risk assessment documentation
  • Measures to address risk documentation
  • Performance measures used to evaluate the effectiveness of risk mitigation measures documentation
  • Correspondence with PHMSA or State/Local Regulatory Agencies related to DIMP implementation.
Operators are required to review and evaluate their DIMP programs periodically and at least every 5 years (§ 192.1007(f)). Operators must retain records related to these reviews for 10 years after they are conducted. If the review results in revision of the DIMP plan, then records associated with that revision must be retained for 10 years. If the review reaffirms the existing DIMP plan, without change, then the records associated with the original DIMP plan, particularly documents demonstrating knowledge of the system, must be retained for another ten years.
Revision: 8/24/11
C.6.2 Must I retain all records I consider in developing my DIMP under §192.1011?

An operator must maintain records demonstrating compliance with the requirements of Subpart P for at least 10 years including those records that specifically detail compliance with the elements in 192.1007. This includes documents related to the development (or subsequent review) of your DIMP plan.

Revision: 5/1/12
C.6.3 Am I required to submit my DIMP Plan to any Federal or State Regulator?

The pipeline safety regulations do not require an operator to submit its DIMP Plan to PHMSA. A copy of the DIMP Plan must be available for inspectors to review during a pipeline safety inspection.

Some states may have requirements regarding DIMP Plan submissions, or DIMP plans may be included in general requirements to submit all required plans. Operators should contact their state regulators for questions concerning state requirements.

PHMSA, or states not requiring filing, may still request a copy of the DIMP plan for purposes such as review prior to an inspection or as an aid in responding to inquiries.

Revision: 8/24/11
C.7 §192.1013 When may an operator deviate from required periodic inspections of this part?

C.7.1 How can operators use their DIMP programs to justify reductions in other periodic test and inspection requirements?

Part 192 includes requirements to perform certain tests and inspections periodically. For example, leak surveys must be conducted annually in business districts and atmospheric corrosion surveys must be conducted every three years on exposed pipe. These activities are intended to address a potential threat to distribution pipeline integrity. As operators complete risk analyses and implement measures directed at addressing threats of particular importance to their pipeline systems, the relative value of these required periodic activities could be shown to decrease in specific areas.

The rule includes a provision which allows operators to submit proposed adjustments to the frequency of periodic actions now required in Part 192, based on the results of their risk assessment in their integrity management programs and engineering analysis. Proposed changes will be reviewed by the regulatory authority exercising oversight of the operator and can be approved if the authority agrees that the proposed changes provide an equal or improved overall level of safety. This provision is intended to allow operators to shift resources from generically-required periodic risk control activities to activities that are more specifically focused on the issues of importance to their particular pipeline systems. The proposal must provide an equal or greater overall level of safety.

Revision: 8/2/10
C.7.2 What will PHMSA (or States) require for proposals for alternate inspection intervals?

Proposals must be submitted to each applicable oversight agency (usually the State). Each State will implement this provision under the State’s procedures. State authorities and regulatory structures differ. Requirements for consideration of an alternative interval may differ among State regulatory authorities. The regulatory authority will be responsible for reviewing each proposal, determining safe intervals based on the information in the operator’s proposal, and approving or rejecting the proposal.

Proposed alternative inspection intervals must demonstrate an equal or improved overall level of safety including the effect of the reduced frequency of periodic inspections. A quantitative estimate of risk is not required. PHMSA is developing criteria for evaluating an operator’s alternative interval proposal in the states where PHMSA exercises enforcement authority over distribution pipelines.

Revision: 8/2/10
C.8 §192.1015 What must a master meter or small liquefied petroleum gas (LPG) operator do to implement this subpart? (Answers from §192.1007 apply to this section unless otherwise noted).


C.8.1Are all LPG operators and natural gas operators, regardless of the size of their distribution system, subject to the DIMP regulation?

The distribution integrity management regulation applies LPG and natural gas operators of all sizes except as provided in 192.1(b).

The requirements under DIMP are the same for master meter operators and small LPG operators. Section 192.1015 is specific to these operators. A master meter operator means a pipeline system for distributing gas within, but not limited to, a definable area, such as a mobile home park, housing project, or apartment complex, where the operator purchases metered gas from an outside source for resale through a gas distribution pipeline system. The gas distribution pipeline system supplies the ultimate consumer who either purchases the gas directly through a meter or by other means, such as by rents. LPG operators serving fewer than 100 customers from a single source are considered small LPG operators. PHMSA used the criterion from section 191.11 which excludes LPG operators serving fewer than 100 customers from a single source from the requirement to file an Annual Report.

LPG operators serving100 or more customers from a single source must meet the same requirements applicable to all natural gas operators. Section 192.1007 is specific to these operators.

Revision: 8/2/10
C.8.2 Why are master meter and small LPG operators subject to different requirements?

The requirements for these smaller operators recognize the less complicated nature of their facilities. Master meter and small LPG systems are generally small and cover limited geographic areas. These operators often have more direct control over excavation in the area in which they operate, providing more positive control over what is the greatest risk to a distribution pipeline system. The systems are also less diverse, usually involving only pipe, meters, and service regulators. There have been few significant incidents on master meter and LPG distribution systems. This justifies a reduced set of integrity management requirements.

Revision: 8/2/10
C.8.3 What do master meter and small LPG operators need to have implemented by August 2, 2011?

By August 2, 2011, master meter operators and small LPG operators must have developed and implemented a written integrity management program that includes a written integrity management plan. The plan must include the operator’s procedures used to develop the elements listed in §192.1015(b)-(c). At a minimum, these operators must have taken the following actions:

  1. Developed and demonstrated an understanding of their system;
  2. Identified and considered threats to each gas distribution facility;
  3. Completed a relative risk ranking of each identified threat to the distribution system;
  4. Developed criteria for deciding when risks require measures to reduce them;
  5. Determined the measures to reduce risk;
  6. Begun implementing the measures to reduce risk or have a plan to implement measures to reduce risk which includes an implementation schedule;
  7. Are monitoring the number of leaks eliminated or repaired on its pipeline and their causes.
  8. Determined the appropriate period for conducting DIMP program evaluations; and
  9. Identified records requiring retention and have maintained them.

Revision: 3/10/11


C.8.a Knowledge

C.8.b Identify Threats

C.8.c Rank Risks

C.8.d Identify and Implement Measures to Mitigate Risks

C.8.e Measure Performance, Monitor Results, and Evaluate Effectiveness

C.8.f Periodically Evaluation and Improvement