DIMP Inspection Forms
The State-Federal Distribution Integrity Management Program (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 DIMP. The Team developed inspection forms for evaluation of an operator’s DIMP. States will implement the DIMP regulations under their individual state statutory authority. Since State authority and regulatory structures differ, operators should contact the regulatory authority exercising jurisdiction over their distribution pipelines for more information. All DIMP inspection forms can be found in PHMSA’s pipeline library:
The following reports are intended to serve as a technical resource for OPS and State pipeline safety inspectors evaluating operators' distribution integrity management (DIMP) programs.
Distribution Integrity Management: Guidance for Master Meter and Small Liquefied Petroleum Gas Pipeline Operators
This document provides guidance to help master meter operators and small LPG operators (i.e., those serving fewer than 100 customers from a single source) implement the requirements of subpart P of Part 192. Operators of larger distribution pipelines should refer to the Gas Piping Technology Committee (GPTC) guidelines.
[Guidance on Carrying Out Requirements in the Gas Distribution Integrity Management Rule (2013)]
Plastic Piping Data Collection Initiative
The Plastic Pipe Database Committee (PPDC), composed of representatives of the American Gas Association (AGA), American Public Gas Association (APGA), Plastics Pipe Institute (PPI), National Association of Regulatory Utility Commissioners (NARUC), National Association of Pipeline Safety Representatives (NAPSR), National Transportation Safety Board (NTSB) and U.S. Department of Transportation’s (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA), has been coordinating the creation and maintenance of a database of in-service plastic piping system failures and/or leaks with the objective of identifying possible performance issues. Company participation in this initiative is voluntary and the database provides confidentiality for participants.
The PPDC was initially created in response to the NTSB Special Investigation Report, Brittle-Like Cracking in Plastic Pipe for Gas Service and NTSB Recommendation P-98-2 which is now closed. In more recent years the focus of the committee has shifted to provide information that may assist operators and regulators in the context of DIMP. The most recent status report including the latest analysis of data from the PPDC database, along with addtional information is available on the PPDC website: https://www.aga.org/safety/promoting-safety/plastic-pipe-database-collection-initiative/
Gas Piping Technology Committee (GPTC) Guide Material Appendix G-192-8 Distribution Management Integrity Program
The Guide material provides guidance to operators for developing a Distribution Integrity Management Program and compliance with proposed Federal Regulations §§192.1005, 192.1007 and 192.1015 on DIMP. It provides operators with practices that may be considered as they develop and maintain a DIMP specific to their gas distribution systems. The American Gas Association (AGA)serves as the secretariat to the Accredited Standards Committee (ASC) Z380, Gas Piping Technology Committee. The GPTC develops and publishes ANSI Z380.1, Guide for Gas Transmission and Distribution Piping Systems. The DIMP guidelines may be purchased separately from the entire Guide.
More information can be found at: http://www.aga.org/gptc/.
SHRIMP - Simple Handy Rule based Integrity Management Plan
A Distribution Integrity Management Programs (DIMP) plan development tool (SHRIMP) developed by the APGA Security and Integrity Foundation (SIF). While SIF receives funding from PHMSA through a cooperative agreement, the American Public Gas Association (APGA) provides support for the material. All questions pertaining to SHRIMP should be directed to the APGA SIF at www.apgasif.org.
Cross Bores – The Threat Posed by the Installation of Gas Distribution Facilities Using Trenchless Technology
Cross bores are defined as an intersection of an existing underground utility or underground structure by a second-party utility resulting in direct contact that compromises the integrity of either utility or underground structure. For example, a cross bore occurs when a new natural gas line is installed using a trenchless method and intersects an existing underground utility, such as a sewer line. This example may pose no problem initially and can go undetected for months or years. However, if the sewer line becomes blocked and mechanical equipment, such as a rotating auger, is used to clear it, the intersecting gas line can be damaged, resulting in a gas leak. The leaking gas can migrate into buildings via the sewer line, resulting in a potentially dangerous situation.
Issues with cross boring were identified as early as 1972, thus this is not a new problem. The occurrence of cross bores has become more prevalent as the installation of gas distribution facilities using trenchless technology becomes more popular. However, there is limited data on the number of cross bores found per mile of sanitary sewer inspected. Typically sanitary sewer laterals belong to the property owner and are not marked by local municipalities in response to locate requests. Sewer laterals are often not identified on maps due to a lack of requirements and/or technology available at the time of their installation, and they are not locatable using conventional methods since they are commonly non-metallic pipe.
The PPAHC is composed of PHMSA and NAPSR representatives. The PPAHC surveyed States in February 2013 on cross boring practices and developed a report to share the results from that survey and to describe experiences with cross boring practices.
Susceptibility of Certain Older Plastic Pipe to Premature Brittle-like Cracking
The DIMP regulation requires operators to identify potential and existing threats to the integrity of their systems, and materials with known issues must be evaluated to rank the risks they pose. Risk mitigation techniques for older plastic pipe include, but are not limited to replacement of pipe or more frequent and focused leakage surveys to better quantify the risks posed by older plastic pipe susceptible to premature brittle-like cracking. PHMSA has issued safety advisory bulletins to owners and operators of natural gas pipeline distribution systems concerning the susceptibility of certain older plastic pipe to premature brittle-like cracking with the latest being ADB-2007-01 (see below). The National Transportation Safety Board (NTSB) issued a report on April 23, 1998 regarding Brittle-Like Cracking in Plastic Pipe for Gas Service, NTSB/SIR–98/01.
Among the types of suspect gas pipeline materials identified in the PHMSA safety bulletins, certain vintages of Aldyl A polyethylene gas pipelines were noted as being susceptible to brittle-like cracking. Appendix D of the Plastic Pipe Database Committee (PPDC) December 21, 2013 report has information specific to Aldyl resin groups (see above). On June 11, 2014, the Staff of the California Public Utilities Commission issued a Hazard Analysis and Mitigation Report specific to Aldyl A Polyethylene Gas Pipelines. The purpose of the Report is to examine potential hazards in California gas and electric utility operations. The report provides hazard-specific background knowledge and technical analysis and includes recommendations to decision makers for policy improvements and best practices with respect to Aldyl A Polyethylene.
Several gas distribution operators in California provided responses to the Commission’s Report. The operators that provided responses were Catalina Gas System, Pacific Gas & Electric, Southern California Gas Company and San Diego Gas & Electric Company and Southwest Gas.
Associations host education and training programs which operators may find of assistance in complying with the DIMP regulation.
Excavation Damage Prevention Organizations
The Common Ground Alliance (CGA) is a member-driven association dedicated to ensuring public safety, environmental protection, and the integrity of services by promoting effective damage prevention practices. In recent years, the association has established itself as the leading organization in an effort to reduce damages to all underground facilities in North America through shared responsibility among all stakeholders.
The following PHMSA Advisory Bulletins may be relevant to DIMP.
|Advisory Number||Topic||Date Issued|
||Dangers of Abnormal Snow and Ice Build-Up on Gas Distribution Systems
||Safe Operations of Underground Storage Facilities for Natural Gas
||Potential for Damage to Pipeline Facilities Caused by Flooding, River Scour, and River Channel Migration
||Potential for Damage to Pipeline Facilities Caused by the Passage of Hurricanes
||Potential for Damage to Pipeline Facilities Caused by Flooding, River Scour, and River Channel Migration
||Reminder to perform evaluations of their Integrity Management (IM) programs using meaningful performance metrics.
||Construction notification action under Sections 191.22(c)(1) and 195.64(c)(1) require a pipeline operator to notify PHMSA not later than 60 days before certain ‘‘construction’’ related events occur.
||Reminder of Requirements for Liquefied Petroleum Gas and Utility Liquefied Petroleum Gas Pipeline Systems
||T.D. Williamson, Inc. Leak Repair Clamp recall.
||[Docket No. PHMSA-2013-0097] 78 FR 65427 Pipeline Safety: Reminder of Requirements for Liquefied Petroleum Gas and Utility Liquefied Petroleum Gas Pipeline Systems
||Potential for Damage to Pipeline Facilities Caused by Flooding
||Pipeline Safety: Accident and Incident Notification Time Limit: Issuance of Advisory Bulletin.
||PHMSA is issuing this Advisory Bulletin concerning operator integrity management program evaluation using meaningful metrics.
||PHMSA is issuing an Advisory Bulletin regarding communication between pipeline facility operators and the PSAP which serves the local emergency responders during pipeline facility emergencies in communities along the pipeline route. To ensure a prompt, effective, and coordinated response to any type of emergency involving a pipeline facility, pipeline facility operators are required to maintain an informed relationship with emergency responders in their jurisdiction in accordance with § 192.615.
||PHMSA is issuing an Advisory Bulletin to provide clarification to owners and operators of gas distribution pipeline facilities when completing the Mechanical Fitting Failure Report Form, PHMSA F 7100.1–2.
||PHMSA is issuing an Advisory Bulletin to remind operators of gas and hazardous liquid pipeline facilities to verify their records relating to operating specifications for maximum allowable operating pressure (MAOP) required by 49 CFR 192.517 and maximum operating pressure (MOP) required by 49 CFR 195.310.
||PHMSA is issuing an advisory bulletin to owners and operators of natural gas cast iron distribution pipelines and state pipeline safety representatives.
||PHMSA is issuing this notice to advise owners and operators of pipeline facilities of PHMSA's plan for implementing the national registry of pipeline and liquefied natural gas operators. This notice provides updates to the information contained in a PHMSA Advisory Bulletin published on January 13, 2012 (77 FR 2126).
||PHMSA is issuing this advisory bulletin to alert operators using Driscopipe® 8000 High Density Polyethylene Pipe (Drisco8000) of the potential for material degradation.
||PHMSA is issuing this advisory bulletin to remind operators of pipelines and LNG facilities of the need to conduct post accident drug and alcohol testing of all potentially involved personnel despite uncertainty about the circumstances of the accident.
||PHMSA is issuing this advisory bulletin to advise owners and operators of pipeline facilities within PHMSA's plan of the implementation of the national registry of pipeline and liquefied natural gas operators.
||PHMSA -2011-0177: Pipeline Safety: Potential for Damage to Pipeline Facilities Caused by Flooding
||PHMSA -2011-0028: Pipeline Safety: Dangers of Abnormal Snow and Ice Build-Up on Gas Distribution Systems
||PHMSA-2010-0381; Pipeline Safety: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure Using Record Evidence, and Integrity Management Risk Identification, Assessment, Prevention, and Mitigation
||PHMSA-2010-0307: Pipeline Safety: Emergency Preparedness Communications
||Pipeline Safety: Personal Electronic Device Related Distractions
||PHMSA-2010-0078 Pipeline Safety: Girth Weld Quality Issues Due to Improper Transitioning, Misalignment, and Welding Practices of Large Diameter Line Pipe
||PHMSA-2008-0211: Implementation of Revised Incident/Accident Report Forms for Distribution Systems, Gas Transmission and Gathering Systems, and Hazardous Liquid Systems
||PHMSA-2009-0158;Weldable Compression Coupling Installation
||Dangers of Abnormal Snow and Ice Build-up on Gas Distribution Systems
||Issues Related to Mechanical Couplings Used in Natural Gas Distribution Systems
||Correction to Advisory Notice
||Updated Notification of the Susceptibility to Premature Brittle-like Cracking of Older Plastic Pipe
||Notice to Operators of Natural Gas and Hazardous Liquid Pipelines to Accurately Locate and Mark Underground Pipelines Before Construction-Related Excavation Activities Commence
||Inspecting and Testing Pilot-Operated Pressure Relief Valves
||Hazards Associated with de-watering of pipelines
||Notification of the Susceptibility to Premature Brittle-Like Cracking of Older Plastic Pipe; Notice; correction
||Notification of the Susceptibility to Premature Brittle-Like Cracking of Older Plastic Pipe
||Notice to Operators of Natural Gas and Hazardous Liquid Pipelines To Encourage Continued Implementation of Safe Excavation Practices
||Emergency Plans and Procedures for Responding to Multiple Gas Leaks and Migration of Gas into Buildings
||Potential failures due to cracking of plastic pipe in natural gas systems
||Potential failures due to cracking of plastic pipe manufactured by Century Utility Products, Inc.
||Directional Drilling and Other Operations Conducted in Proximity to Underground Pipeline Facilities
||Potential Failure of Check Valves Following Remanufacturing
||Potential Soil Subsidence on Pipeline Facilities
||Potential Damage to Pipelines by Impact of Snowfall, and Actions Taken by Homeowners and Others to Protect Gas Systems from Abnormal Snow Build-up
||Increased Pipeline Transportation Security Measures
||Pipelines Affected by Flooding
||Pipelines in a common right-of-way, parallel right-of-way, or cross a rail right-of-way
||Valve Location and Spacing
||Advisory to Owners and Operators of Hazardous Liquid and Natural Gas Pipeline Facilities in Areas of Flooding
||Pipeline Safety Advisory Bulletin; Snow Accumulation on Gas Pipeline Facilities
||Addresses concerns arising from Allentown, PA, explosion
||Lightning-induced electrical discharge from tracer wire to plastic pipe.
||NTSB recommendations S P-91-3/P-91-4, 03/15/90 NY leak/explosion: Requiring operators to extend their public education/emergency preparedness programs
||NTSB SR P-91-2 Texas Eastern Product Pipeline Company Explosion 2/20/90: Actions to be taken before moving a pipeline
||NTSB recently issued recommendation P-91-12 related to the August 1990 explosion and fire in Allentown, PA, caused by a crack in a 4-inch cast iron gas main.
||Results of OPS-conducted investigation of the San Bernardino, CA, 05/12/89 train derailment; each gas/liquid operator should test check valves.
||Update: Additional findings relative to factors contributing to operational failures of pipelines constructed by ERW prior to 1970
||Recent findings relative to factors contributing to operational failures of pipelines constructed with ERW prior to 1970
||Incident involving the fillet welding of a full encirclement repair sleeve on a 14" API 5LX-52 pipeline; King of Prussia, PA 10/07/86 pipeline failure
||Plastic Piping, Mechanical Coupling
||Use of stainless steel band clamps for permanent repair of damaged plastic pipe.