# U.S. DOT/PHMSA - Report to Congress - Evaluation of Expanding Pipeline Integrity Management Beyond High-Consequence Areas and Whether Such Expansion Would Mitigate the Need for Gas Pipeline Class Location Requirements - Pipeline Safety, Regulatory Certainty, And Job Creation Act 2011, Section 5

**Citation:** 0900006482028f72  
**Type / status:** rulemaking / current  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** Not stated

Report to Congress Evaluation of Expanding Pipeline Integrity Management Beyond High-Consequence Areas and Whether Such Expansion Would Mitigate the Need for Gas Pipeline Class Location Requirements Pipeline Safety, Regulatory Certainty, And Job Creation Act 2011, Section 5 April 2016 Office of Pipeline Safety Pipeline and Hazardous Materials Safety Administration U. S.... Table of Contents Executive Summary ...................................................................................................................................... ii 1. INTRODUCTION ................................................................................................................................ 1...

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Report to Congress
Evaluation of Expanding Pipeline Integrity
Management Beyond High-Consequence Areas and
Whether Such Expansion Would Mitigate the
Need for Gas Pipeline Class Location Requirements
Pipeline Safety, Regulatory Certainty,
And Job Creation Act 2011, Section 5
April 2016
Office of Pipeline Safety
Pipeline and Hazardous Materials Safety Administration
U. S. Department of Transportation

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Table of Contents
Executive Summary ...................................................................................................................................... ii
1. INTRODUCTION ................................................................................................................................ 1
2. EXPANSION OF IM REQUIREMENTS BEYOND HCAs (The Act § 5(a)(1)) ................................ 1
2.1 History of IM Program .................................................................................................................. 1
2.1.1 History of Hazardous Liquid IM Program............................................................................ 1
2.1.2 History of Gas Transmission Integrity Management Program ............................................. 2
2.2 ANPRM: Safety of Hazardous Liquid Transmission Pipelines .................................................... 4
2.3 ANPRM: Safety of Gas Transmission Pipelines .......................................................................... 4
2.4 Expanding IM Requirements to Areas Outside HCAs ................................................................. 6
2.4.1 Hazardous Liquid ......................................................................................................................... 6
2.4.2 Gas Transmission ......................................................................................................................... 7
2.4.3 Notice of Proposed Rulemaking ................................................................................................. 10
3. DOES EXPANSION OF IM BEYOND HCAs MITIGATE THE NEED FOR CLASS
LOCATIONS? (The Act § 5(a)(2)) ............................................................................................................ 11
3.1 Class Locations (Background) .................................................................................................... 11
3.1.1 History of Class Locations .................................................................................................. 11
3.1.2 Purpose of Class Locations ................................................................................................. 14
3.2 ANPRM: Safety of Gas Transmission Pipelines ........................................................................ 22
3.3 Notice of Inquiry: Class Location Requirements ........................................................................ 24
3.3.1 History leading up to Request for Comments on Class Location Regulations ................... 24
3.3.2 Summary of Comments Received on Need for Modifying Class Locations ........................ 24
3.4 Pipeline Advisory Committee Meeting ....................................................................................... 25
3.5 Class Location Workshop ........................................................................................................... 27
3.6 Class Location Approach versus IMP Approach ........................................................................ 34
3.7. Alternatives to Class Locations ................................................................................................... 38
3.7.1 Single Design Factor .......................................................................................................... 38
3.7.2 Sliding Mile Based upon Potential Impact Radius ............................................................. 38
3.7.3 Expand Class Locations ...................................................................................................... 42
3.7.4 Bifurcated Approach ........................................................................................................... 42
3.7.5 Revise §192.611 to Include Additional IM Oriented Methods for Addressing Class
Location Changes ............................................................................................................................... 42
3.7.6 No Change in Class Location Methodology ....................................................................... 42
4. CONCLUSION ................................................................................................................................... 43
5. FUTURE CONSIDERATION OF CLASS LOCATION ................................................................... 43
Appendix A - Abbreviations ..................................................................................................................... A-1
Appendix B – Class Location Waiver Criteria ......................................................................................... B-1
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Report to Congress
Evaluation of Expanding Integrity Management
Beyond HCAs and Whether Expansion Would Mitigate the
Need for Class Location Requirements April 2016
Executive Summary
Section 5(c) of the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 (the Act)
(Pub. L. 112-90) requires the Secretary of Transportation to “evaluate (1) whether integrity
management (IM) system requirements, or elements thereof, should be expanded beyond high
consequence areas (HCAs); and (2) with respect to gas transmission pipeline facilities, whether
applying IM program requirements, or elements thereof, to additional areas would mitigate the
need for class location requirements.” Section 5(f) of the Act authorized the Pipeline and
Hazardous Materials Safety Administration (PHMSA) to issue regulations in accordance with
the report after the conclusion of a review period. This report documents that evaluation and
addresses whether IM program requirements should be expanded beyond high consequence areas
(HCAs) and, specifically for gas transmission pipelines regulated under 49 Code of Federal
Regulations (CFR) Part 192, whether such expansion would mitigate the need for class location
designations and corresponding requirements. PHMSA conducted a class location public
meeting on April 16, 2014, and requested public comments to be submitted to Docket Number
PHMSA-2013-01611 located on the internet at regulations.gov. Public comments received on
the docket were evaluated.
In October 2010 and August 2011, PHMSA published notices in the Federal Register to solicit
comments on revising the pipeline safety regulations applicable to hazardous liquid and natural
gas transmission pipelines including expansion of IM program requirements beyond HCAs. In
general, industry representatives and pipeline operators were opposed to any expansion of HCAs
and in favor of eliminating class locations on newly constructed pipelines, whereas public
interest groups were in favor of expanding HCAs but against curtailing class location
requirements.
PHMSA has carefully considered the input and comments. At this time, PHMSA plans to
propose an approach that balances the need to provide additional protections for persons within
the potential impact radius (PIR) of a pipeline rupture (outside of a defined HCA), and the need
to prudently apply IM resources in a fashion that continues to emphasize the risk priority of
HCAs. PHMSA, therefore, is considering an approach that would require selected aspects of IM
programs (namely, integrity assessments and repair criteria) to be applicable for non-HCA
segments. For hazardous liquid pipelines, PHMSA would propose to apply these requirements
for non-HCA pipeline segments.
2 For gas transmission pipelines, PHMSA would propose to
apply these requirements where persons live and work and could reasonably be expected to be
located within a pipeline PIR. Under this approach, PHMSA would propose requirements that
1 On August 25, 2011, (76 FR 53086) PHMSA published in the Federal Register an Advance Notice of Proposed
Rulemaking (ANPRM) titled: “Safety of Gas Transmission Pipelines” seeking comments on the need for changes
to the regulations covering gas transmission pipelines. Public comments from this ANPRM are posted on Docket
Number PHMSA-2011-0023 located on the internet at regulations.gov.
2 Gas and Hazardous Liquid (HL) Notices of Proposed Rulemaking (NPRM) both protect the safety of humans in a
similar manner. The difference is the environmental effects of HL versus gas releases on the environment
including the effects on soils, streams, and rivers. Due to gas being lighter than air, gas rises up and does not
pollute soil, streams, and rivers compared to hazardous liquids such as crude oil which is heavier than air.
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Beyond HCAs and Whether Expansion Would Mitigate the
Need for Class Location Requirements April 2016
integrity assessments be conducted, and that injurious anomalies and defects be repaired in a
timely manner, using similar standards in place for HCAs. However, the other program elements
of a full IM program contained in 49 CFR Part 192, Subpart O, or 49 CFR Section 195.452 (as
applicable) would not be required for non-HCA segments.
The Act also required the Secretary of Transportation to evaluate if expanding IM outside of
HCAs for gas transmission pipelines, as discussed above, would mitigate the need for class
location requirements.
Expanding IM Requirements Beyond HCAs
Based upon findings from lessons learned, accident investigations, assessments, IM, and
operations and maintenance (O&M) considerations, PHMSA is proposing through a notice of
proposed rulemaking (NPRM) to apply selected IM program elements (i.e. assessments and
remediation on a continuing interval) to areas outside HCAs. For gas transmission pipelines, the
assessment and remediation requirements would be limited to selected areas outside HCAs
identified in this report as moderate consequence areas (MCAs). This integrity assessment
approach for non-HCA locations is addressed in separate NPRMs for both gas transmission and
hazardous liquid pipelines.
Class Location
On August 1, 2013, PHMSA published a notice in the Federal Register (78 FR 46560) soliciting
comments on expanding gas IM program requirements and mitigating class location
requirements (Class Location Notice). Comments in the Class Location Notice were solicited on
whether:
1. PHMSA should increase the existing class location design factors in densely populated
areas with building over four stories?
2. Class locations should be eliminated and a single design factor used, if IMP requirements
are expanded beyond HCAs?
3. Should there be only a single design factor for pipeline areas where there are large
concentrations of populations along the pipeline; such as schools, hospitals, nursing
homes, multiple-story buildings, stadiums, and shopping malls, as opposed to rural areas
like deserts and farms where there are fewer people?
A class location workshop was held on April 16, 2014, to discuss this notice and comments were
received from stakeholders, including industry representatives, pipeline operators, state
regulatory agencies, and the public. Based on PHMSA’s evaluation of written comments and
stakeholder input at the workshop, PHMSA considered several alternatives for changing the
current regulations with respect to defining class locations and how to approach changes in class
location, when they occur, which include:
Single Design Factor
PHMSA solicited comments on the use of a single design factor for all pipeline class locations as
an alternative to the current method for determining class locations. The proposal was to use a
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Evaluation of Expanding Integrity Management
Beyond HCAs and Whether Expansion Would Mitigate the
Need for Class Location Requirements April 2016
higher design factor where there are large concentrations of populations, such as schools,
hospitals, nursing homes, multiple-story buildings, stadiums, and shopping malls.
The comments on the use of a single design factor were overwhelmingly negative. Commenters
felt that, to mitigate class locations by going to a single design factor approach would impact too
many of the existing requirements in 49 CFR Part 192, including design, construction, and
operational inspections and would be complicated to implement and may result in a decrease in
safety in populated areas.
Sliding Mile Based upon Potential Impact Radius
The current sliding mile methodology for determining a class location unit could be replaced by
a methodology based on the HCA PIR. Some pipeline industry comments suggested this
approach may have merit for new and replaced pipe instead of existing pipe. An additional
safety factor would be considered if this method were proposed. One operator proposed a
method similar to the PIR approach. The operator called it “the Class Location Circle”
approach. The Class Location Circle would be either 300 feet in radius or the PIR of the pipeline
whichever results in a larger area. Also, another operator proposed a redefinition of the class
location densities over those currently found in 49 CFR Section 192.5.
Expand Class Locations
Gas transmission pipelines are currently classified as Class 1, 2, 3, or 4 locations. A Class 4
location is defined as a class location where buildings of four (4) or more stories are prevalent.
Heavily developed urban areas have many buildings over four stories high. While some
commenters felt that the existing class location approach should be retained and expanded to
include additional class locations for densely populated urban areas with buildings over four
stories tall, a majority of industry and operator commenters were against adding additional class
locations. The industry representatives and pipeline operators felt that new class locations with
design factors lower than the current 0.4 design factor for Class 4 locations would make it
difficult to continue to supply natural gas to the newly classified areas.
Bifurcated Approach
The Interstate Natural Gas Association of America (INGAA) submitted a written request to keep
the current method for existing pipelines, but add a new method using the PIR approach for new
construction and replaced pipelines. This approach would utilize the HCA PIR type approach
for new or replaced pipelines only and would keep the current class location definitions and
applications for existing pipelines.
INGAA’s bifurcated approach would allow class location changes to existing pipe including pre-
Code pipe with additional operational and integrity measures, and new pipelines with a single
design factor in all class locations to have additional material, construction and integrity
measures.
Class Location Changes – Allow Additional IM Assessments
One alternative being considered is to retain the current method for determining class locations
but to revise the regulations for addressing changes in class locations. Such changes might
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Need for Class Location Requirements April 2016
include alternatives in addition to pipe replacement, retesting, or de-rating, such as incorporation
of IM practices to validate the condition of the pipe and monitor the pipe within an IM process.
Specifically, the INGAA suggested that PHMSA consider and engage stakeholders regarding
eighteen categories of standards or requirements that could be developed through rulemaking to
replace the current Class Location Special Permits program. The eighteen categories suggested
by INGAA are similar to the conditions PHMSA has used in granting class location special
permits. Such an approach would provide regulatory certainty.
No Change
Retain the current 49 CFR Part 192 methods for determining class location (definition) and class
location changes along with the requirements that correspond with those designations, including
Maximum Allowable Operating Pressure (MAOP), pressure testing, operational inspections and
inspection intervals.
Conclusion
Overall, the majority of stakeholder responses suggested that PHMSA not change the current
class location approach for class locations and class location changes as population increases
used for establishing MAOP and O&M surveys for existing pipelines. For new transmission
pipelines, some industry groups and operators supported some type of bifurcated approach for
existing and new pipelines as described above. Other commenters suggested alternatives to
requirements that sometimes result in pipe replacement when class location changes.
For gas transmission pipelines, PHMSA believes the application of IM assessment and
remediation requirements to MCAs does not warrant elimination of class locations. Class
locations affect all gas pipelines, including transmission (interstate and intrastate), gathering, and
distribution pipelines, whether they are constructed of steel pipe or plastic pipe. Class location is
integral to determining MAOPs, design pressures, pipeline repairs, HCAs, and O&M inspections
and surveillance intervals.
3 Class locations affect 12 subparts and 28 sections of 49 CFR Part
192 for gas pipelines. The subparts and sections are listed and discussed in Sections 3.1.2.4 and
3.7.2.2. While assessment and remediation of defects on gas transmission pipelines is an
important risk mitigation program, it does not adequately compensate for other aspects of class
location as it relates to other types of gas pipelines and as it relates (for all gas pipelines) to the
original pipeline design and construction such as the design factor, initial pressure testing,
establishment of MAOP, O&M activities, and other aspects of pipeline safety, that are based on
class location. Also, there are some disadvantages to using only the PIR circle method without
inclusion of class locations that use human dwelling counts or buildings within the PIR. For
instance: (a) PIR approach may exclude buildings/homes for PIRs less than 660 feet, which
could be impacted from a pipeline rupture and are now included in the class location unit, (b)
PIR approach does not take into account pipe wall thickness, grade, seam type, testing history, or
3 PIR could be used as an alternative to the class location spacing unit (§ 192.5(a)(1)) of 220 yards (660 feet) on
either side of the pipeline used to determine class locations for new pipelines. The class location dwelling count
would need to have similar numbers as defined in § 192.5 for either the current class location unit or a “PIR
based” class location unit. In this way, the PIR approach could be used to define class locations in order to
construct risk/design factor categories.
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Need for Class Location Requirements April 2016
design factor, and (c) it may not take into consideration future development adjacent to PIR
circle without requirements for future surveys. Thus, PHMSA has preliminarily determined to
not eliminate the existing class location requirements. 4
Future PHMSA Consideration of Class Location
PHMSA acknowledges that, although it has decided to not eliminate class location requirements
at this time, industry raised some legitimate issues with the existing rules, or lack thereof, for
implementing class location. PHMSA will continue to listen to stakeholder input and consider:
• Comments and suggested approaches submitted on the docket in response to this report;
Docket Nos. PHMSA-2011-0023, PHMSA -2013-0161 and the April 16, 2014 Class
Location Workshop presentations are on the below link:
http://primis.phmsa.dot.gov/meetings/MtgHome.mtg?mtg=95
• More efficient and practical class location approaches that provide appropriate safety and
avoid unnecessary costs such as unnecessary pipe replacement.
PHMSA will continue to study and consider if adjustments are needed to class location
requirements. PHMSA will consider these issues in the context of other issues it is addressing
related to new construction quality management systems (QMS) and safety management systems
(SMS). PHMSA will also consider inspection findings, IM assessments, and lessons-learned
from past incidents. Any changes to the definition and application of class locations in 49 CFR
Part 192 will require a very thorough process. PHMSA plans to further evaluate the feasibility
and the appropriateness of each alternative, continue to reach-out to all stakeholders, consider
input from all sources, and consider future rulemaking if a cost-effective and safety focused
approach to adjusting specific aspects of class location requirements can be developed in order to
address the issues identified by industry.
4 PHMSA did not analyze the cost. The potential pros and cons are highlighted in Section 3 of this report.
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Evaluation of Expanding Integrity Management
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Need for Class Location Requirements April 2016
1. INTRODUCTION
The Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 (the Act), Section 5,
requires the Secretary of Transportation to evaluate and issue a report evaluating whether IM
system requirements, or elements thereof, should be expanded beyond HCAs and, with respect to
gas transmission pipeline facilities, whether applying IM program requirements to these
additional areas would eliminate or reduce the need for class location requirements.
In conducting the evaluation the Act required the following, at a minimum, to be considered:
1. Continued protections for public safety;
2. Continued reduction of risk in HCAs;
3. Cost of applying IM standards to pipelines outside of HCAs where operators are already
conducting assessments beyond what is required under Chapter 601 of Title 49, United
States Code;
4. Achievable and sustainable IM assessments and repairs with limited disruption in
pipeline service;
5. Options for phasing in any extension of IM requirements beyond HCAs, including the
most effective and efficient options for decreasing risks to an increasing number of
people living or working in proximity to pipeline facilities; and
6. The appropriateness of applying repair criteria, pressure reductions, and other special
safety requirements for scheduling remediation to areas outside of HCAs.
To perform the evaluation, PHMSA solicited comments from stakeholders including industry
representatives, pipeline operators, regulatory agencies, and public interest groups.
2. EXPANSION OF IM REQUIREMENTS BEYOND HCAs
(The Act § 5(a)(1))
2.1 History of IM Program
2.1.1 History of Hazardous Liquid IM Program
On October 24, 1992, the Pipeline Safety Act of 1992 (Pub. L. 102-508) was enacted
establishing the foundation for taking a risk-based approach to pipeline safety. 5 The law
directed DOT, through the Research and Special Programs Administration (RSPA), a
predecessor agency to PHMSA, to prescribe, if necessary, additional standards requiring the
periodic inspection of each pipeline in high population density areas or in areas unusually
sensitive to environmental damage (collectively referred to as high consequence areas or HCAs).
In response to this directive, the Office of Pipeline Safety (OPS) 6 created several initiatives,
some of which include the Risk Management Demonstration Program and the Systems Integrity
Inspection Program. In 1999, OPS held a public meeting7 to consider the lessons learned from
5 Two years later, Public law 103-272 re-codified many provisions of this Act in Title 49 U.S. Code.
6 OPS is the office within PHMSA that carries out national programs to ensure the safe, reliable and environmentally
sound operation of the United States pipeline transportation systems.
7 Federal Register (64 FR 56725, October 21, 1999).
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Beyond HCAs and Whether Expansion Would Mitigate the
Need for Class Location Requirements April 2016
these initiatives. The goal was to evaluate the need for additional regulations to provide greater
assurance of pipeline integrity in high-density population areas, waters where a substantial
likelihood of commercial navigation exists, and areas unusually sensitive to environmental
damage. At this public meeting, OPS expressed its intent to incorporate a process into its
regulations to validate pipe integrity in these HCAs. The resulting hazardous liquid pipeline IM
regulations were implemented in two phases. The first phase was IM regulations for operators
with 500 miles (or more) of hazardous liquid pipelines8 and the second phase was for operators
with less than 500 miles of hazardous liquid pipelines.9
2.1.2 History of Gas Transmission Integrity Management Program
Beginning in January 2000, OPS began meeting with industry groups, research institutions, gas
transmission operators, state pipeline safety agencies, public interest parties, and other groups of
interest to gain a clear understanding of the characteristics of a gas transmission pipeline incident
in order to develop a definition of a HCA for gas transmission pipelines. A public meeting was
held to solicit comments on Gas Transmission Pipeline Integrity Management in HCAs.
10 A
second public
meeting11 was held to seek further information and clarification and obtain further public
comments on IM concepts as they apply to gas transmission pipelines. At the second public
meeting, OPS provided elements of a proposed gas transmission pipeline IM program.
Subsequently, OPS published the first definitions of what defines a Gas Transmission HCA.
12
HCAs were initially defined as:
• Class 3 and Class 4 location;
• An area where a pipeline is within 660 feet (1000 feet where the pipeline is 30 inches in
diameter and operates at a MAOP of 1000 psig or more) of a hospital, school day-care
facility, retirement facility, prison or other facility having persons who are confined, are
of impaired mobility, or would be difficult to evacuate; and
• An area where a pipeline lies within 660 feet (1000 feet where the pipeline is 30 inches in
diameter and operates at an MAOP of 1000 psig or more) where 20 persons congregate at
least 50 days in any 12 month period.
The definition of an HCA was finalized on August 6, 2002.13 The only change from the January
9, 2002, definition was that for pipelines 12 inches or less in diameter and operating at an MAOP
of less than 1200 psig, an HCA was an area where a pipeline is within 300 feet of a building
occupied by persons who are confined, are of impaired mobility, or would be difficult to
evacuate. For pipelines greater than 12 inches in diameter, the distance was 660 feet and 1000
8 Federal Register (65 FR 75378, December 1, 2000).
9 Federal Register (67 FR 2136, January 16, 2002).
10 Federal Register (66 FR 848, January 4, 2001).
11 Federal Register (66 FR 34318, June 27, 2001).
12 Federal Register (67 FR 1108, January 9, 2002).
13 Federal Register (67 FR 50824, August 6, 2002).
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feet for pipelines greater than 30 inches in diameter and operating at greater than 1000 psig
MAOP.14
On December 17, 2002, the PSIA of 2002 was signed into law (Pub. L. 107-355). Section 14,
“Risk Analysis and Integrity Management Programs for Gas Pipelines,” required the Secretary of
Transportation to develop and implement an IM program for gas transmission pipeline facilities.
A NPRM15 was published proposing requirements to implement Section 14 of the PSIA of 2002.
These NPRM requirement areas included:
• Intervals for conducting baseline and reassessment testing;
• Consideration of pressure testing conducted prior to the final rule;
• Incorporation of issues raised by state and local authorities;
• Conducting of pressure testing in an environmentally appropriate manner;
• Operator notification to RSPA of changes to its IM program; and
• Record sharing of operator records with state interstate agents.
In this NPRM, OPS proposed a change to the definitions of a HCA. The concept of a covered
segment was introduced. A covered segment was defined as the length of gas transmission
pipeline that could potentially impact an HCA.16 Previously, only distances from the pipeline
centerline were discussed in relation to HCA definitions. The concept of using Potential Impact
Circles, Potential Impact Zones, and Potential Impact Radii to identify covered segments, instead
of a fixed corridor width, was introduced.17
Following the publication of the NPRM, RSPA held workshops and public meetings18 to solicit
comments on the proposed gas transmission pipeline IM regulations. The culmination of these
public meetings was the issuance of the Gas Transmission Pipeline Integrity Management final
rule on December 15, 2003,19 which added Subpart O, “Gas Transmission Pipeline Integrity
Management” to 49 CFR Part 192.
14 The influence of the existing class location concept on the early definition of HCAs is evident from the use of
class locations themselves in the definition, and the use of fixed 660 ft. distances which corresponds to the
corridor width used in the class location definition. This concept was later significantly revised, as discussed
later, in favor of a variable corridor width (referred to as the Potential Impact Radius) based on case-specific pipe
size and operating pressure.
15 Federal Register (68 FR 4278, January 28, 2003).
16 HCA and PIR definitions can be found in 49 CFR § 192.903.
17 The use of the PIR to define high consequence areas is a significant aspect of IM and greatly influences the notion
that the existing class location approach might be outdated and might mitigate the need for class locations. That
issue, and the contrast between the two approaches is discussed in Section 3 of this report.
18 Federal Register (68 FR 6385, February 7, 2003); Federal Register (68 FR 9966, March 3, 2003); and Federal
Register (68 FR 17594, April 10, 2003).
19 Federal Register (68 FR 69778, December 15, 2003).
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2.2 ANPRM: Safety of Hazardous Liquid Transmission Pipelines
In October 2010, PHMSA published an ANPRM seeking comments on revising the pipeline
safety regulations applicable to the safety of hazardous liquid pipelines.
20 PHMSA stimulated
feedback by asking a series of detailed questions in six (6) specific topic areas related to
hazardous liquid pipelines. These topic areas included:
• Scope of the pipeline safety regulations and existing regulatory exceptions;
• The criteria for designation as a HCA;
• Leak detection and Emergency Flow Restricting Devices (EFRD);
• Valve spacing;
• Repair criteria in non-HCA areas; and
• Stress corrosion cracking (SCC).
Under each of these specific topic areas PHMSA requested responses to these questions. In
response to the ANPRM, PHMSA received 24 comments which are available in the docket21 at
regulations.gov. The pipeline industry consensus was that the regulations as written were
adequate. The industry asserted that significant improvement in the safety record of hazardous
liquid pipelines had been made since the promulgation of IM rules and any modifications to the
regulations should be limited. On the issue of repairs in non-HCA areas, industry representatives
felt that assessments were being performed in non-HCA areas and that IM repair criteria would
be voluntarily applied to any anomalies found in these areas.
2.3 ANPRM: Safety of Gas Transmission Pipelines
During August 2011, PHMSA published an ANPRM seeking comments on revising the pipeline
safety regulations applicable to the safety of gas transmission pipelines.22 PHMSA stimulated
feedback by asking a series of detailed questions in 15 general topic areas related to gas
transmission pipelines, gas gathering pipelines, and underground storage facilities. The general
topic areas relating to gas transmission IM and expanding IM programs outside of HCAs in this
ANPRM included:
• Whether IM requirements should be changed;
• Whether issues related to system integrity should be addressed by expanding non-IM
requirements;
• Whether the definition of a HCA should be revised; and
• Whether additional restrictions should be placed on the use of specific pipeline
assessment methods.
In response to the ANPRM, PHMSA received over 100 comments letters containing over 1,400
individual comments, which are available on the docket.23 Significant and extensive comments
20 Federal Register (75 FR 63774, October 18, 2010).
21 Docket PHMSA-2010-0229.
22 Federal Register (76 FR 53086, August 25, 2011).
23 Docket PHMSA-2011-0023 found at regulations.gov.
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on the topic of expanding IM were provided. The input generally fell into three broad
categories:
1. Those who advocated the significant expansion of the full IM program to more pipeline
segments (i.e., redefining HCAs to encompass more pipe segments, some of which
advocated incorporation of critical infrastructure and/or additional class locations for
urban, densely populated areas using even more stringent design safety factors than
currently required by 49 CFR Part 192);
2. Design safety factors are factors that ensure the pipeline operating pressures are operated
below 100 percent of the maximum pipe strength. Design safety factors are developed
based upon risk to the public (number of human dwellings near the pipeline or type of
dwelling – hospital, school, or nursing care facility) and for piping that may have
additional operational stresses such as compressor stations, metering stations,
fabrications, river crossings, and road/railroad crossings. Safety factors for the pipeline
vary― Class 1, with a design factor of 0.72; Class 2, with a design safety factor of 0.60;
Class 3, with a design safety factor of 0.50, and Class 4, with a design safety factor of
0.40. The lower the safety factor the stronger the pipe must be for the MAOP of the
pipeline through thicker pipe and/or higher steel grades. Those who advocated that more
stringent and/or more prescriptive standards be applied to existing IM requirements (in
lieu of performance-based or programmatic requirements); and
3. Those who advocated that the existing IM rules were appropriate and that industry should
be permitted to apply IM principles to non-HCA pipe segments in a voluntary basis.
Specifically, INGAA and a number of gas transmission pipeline operators noted that this was an
opportune time for considering the next steps in IM, since baseline assessments under the current
IM rules were being completed. INGAA noted its policy goal was to apply IM principles (as
described in the national consensus standard ASME/ANSI B31.8S) beyond HCAs, covering 90
percent of people living near transmission pipelines by 2020 and 100 percent by 2030.24
Similarly, TransCanada submitted information in support of INGAA’s proposal, noting that by
the end of 2012 the company will have assessed more than 85 percent of its U.S. pipeline
mileage covering more than 95 percent of people living near their pipelines. However,
TransCanada stated that it believed significant technological challenges would be encountered if
IM regulations were extended to all pipeline segments as noted:
TransCanada stated “achieving the goal of 100% population coverage is not without its
challenges. This incremental mileage contains significant technical and operational
challenges including; small diameter pipelines, single source feeds to customers, multi-
diameter pipelines, low flow pipelines that would preclude the use of free-swimming in-line
inspection tools, and station piping which contains complex geometries and excavation
challenges due to nearby piping and other underground utilities. The availability of
improved integrity management principles, including new technology, will be important as
24 Letter from Terry D. Boss, Senior Vice President of Environment, Safety and Operations, Interstate Natural Gas
Association of America, Safety of Gas Transmission Pipelines, Docket No. PHMSA-2011-0023, dated January 20,
2012. http://www.regulations.gov/#!documentDetail;D=PHMSA-2011-0023-0082
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we address these hard-to-assess areas. We will continue to support and participate in R&D
efforts including development of new inspection and assessment technology to facilitate this
goal.”
PHMSA is not proposing additional IM regulations to take the place of class locations.
2.4 Expanding IM Requirements to Areas Outside HCAs
PHMSA has carefully considered the extensive input and comments received to date and plans to
propose an approach that balances the need to provide additional protections for persons within
the PIR of a pipeline (but that is not a defined HCA), and the need to prudently apply IM
resources in a fashion that continues to emphasize the priority of HCAs. PHMSA, therefore, is
considering an approach that would require selected aspects of IM programs (namely, integrity
assessments and repair criteria) to apply to non-HCA segments. For hazardous liquid pipelines,
PHMSA would propose to apply these requirements for non-HCA pipeline segments. For gas
transmission pipelines, PHMSA would propose to apply these requirements where persons live
and work and could reasonably be expected to be located within a pipeline PIR. PHMSA would
propose to promulgate a rule that would require that integrity assessments be conducted, and that
significant anomalies and defects be repaired in a timely manner, using similar standards in place
for HCAs. However, some of the other program elements of the IM program requirements
contained in 49 CFR Part 192, Subpart O, or 49 CFR § 195.452 (as applicable) would not be
mandatory for non-HCA segments.
2.4.1 Hazardous Liquid
Periodic assessments, particularly with inline inspection (ILI) tools, provide critical information
about the condition of a pipeline, but are currently only required under the IMP requirements
found in §§ 195.450 and 195.452. PHMSA believes that pipeline operators should be required to
have the information needed to promptly detect and remediate conditions that could adversely
affect the safe operation of pipelines in all areas. Accordingly, PHMSA is considering requiring
operators to perform assessments of pipelines that are not already subject to the IM requirements
at least once every 10 years. Currently, approximately 82,933 miles of hazardous liquid
pipelines could affect HCAs, out of approximately 190,958 total hazardous liquid pipeline miles.
This represents 43.4 percent of the hazardous liquid pipeline mileage in the country. PHMSA is
considering requiring that integrity assessments be performed on the remaining 108,025 miles of
hazardous liquid pipelines25 every 10 years. This is less than the current 5-year interval for
mandatory integrity assessments for hazardous liquid pipeline segments in HCAs.
PHMSA acknowledges that operators are already assessing pipeline mileage outside of HCAs
and estimates that 90% of the total hazardous liquid pipeline mileage26 has been assessed under
25 The mileages are reported mileages on Operator Annual Reports during May 2014.
26 API comment to PHMSA for the Hazardous Liquid (HL) ANPRM provided by AOPL-API in a letter dated
February 18, 2011. In a survey of its member pipeline companies (covering 93,867 miles), API found that through
the course of assessing HCA segments and pipelines near those segments, operators had assessed 83 percent of
their non-HCA mileage. When combined with HCA mileage that had been assessed, this represents 90 percent of
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IMP requirements. PHMSA estimates that approximately 87,000 miles of pipelines outside of an
HCA are already being assessed in conjunction with the assessment of HCA mileage.
Since most hazardous liquid pipelines can be assessed using ILI technology, PHMSA believes
that those assessments should be performed with ILI tools, unless an operator demonstrates that a
pipeline is not capable of accommodating such tools and that an alternative method will provide
a substantially equivalent understanding of pipeline integrity. PHMSA would also likely require
that the results of these assessments be reviewed by persons qualified to determine if any
conditions exist that could affect the safe operation of a pipeline; that such determinations be
made promptly; and that any unsafe conditions be remediated in a schedule analogous to existing
provisions for remediating HCA segments in the current IMP regulations.
Currently § 195.422 prescribes general requirements for pipeline repair procedures. For non-
HCA segments, § 195.401(b) (1) requires that “whenever an operator discovers any condition
that could adversely affect the safe operation of its pipeline system, it must correct the condition
within a reasonable time. However, if the condition is of such a nature that it presents an
immediate hazard to person or property, the operator may not operate the affected part of the
system until it has corrected the unsafe condition.” PHMSA believes that more specific repair
criteria are needed for hazardous liquid pipelines outside of HCAs and would:
• Define immediate repair conditions;
• Require immediate repair conditions be remediated upon discovery;
• Require operating pressures be reduced until immediate repair conditions are remediated;
and
• Require non-immediate repair conditions to be remediated within 18 months of
discovery.
While it is estimated that 90% of hazardous liquid pipelines are being assessed under the IM rule
requirements, pipelines located outside of HCAs currently do not have to be repaired within the
time frames required by the IM program rules. PHMSA is considering that defects in non-HCA
pipeline segments meeting the immediate repair conditions should be repaired upon discovery,
but that the time frame for remediating non-immediate repair conditions for these segments
could be modified.
PHMSA believes that establishing requirements for assessing and repairing non-HCA pipeline
segments is important because accidents have occurred in non-HCA segments that resulted in
extensive environmental damage and enormous remediation costs.
2.4.2 Gas Transmission
Currently, Part 192 does not contain any requirement for operators to conduct integrity
assessments of onshore transmission pipelines that are not located in HCAs as defined in
§ 192.903 and, therefore, not subject to Subpart O (i.e., pipelines that are not located in a
the total mileage for the survey respondents. PHMSA has placed this comment letter in the docket for the HL
NPRM.
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HCA).27, 28 Approximately 7 percent or 20,00029 miles out of 300,00030 miles of onshore gas
transmission pipelines are located in HCAs. However, coincident with integrity assessments of
HCA segments, industry has, as a practical matter, assessed substantial amounts of onshore gas
pipelines in non- HCA segments. For example, INGAA noted that approximately 90 percent of
Class 3 and 4 location transmission mileages not in HCAs are presently assessed during IM
assessments. This is due, in large part, because ILI or pressure testing, by their nature, assesses
large continuous segments that may contain some HCA segments but that could also contain
significant mileage of non- HCA segments.
INGAA members31 have committed to perform pipeline assessments using IM principles
outside HCAs so that approximately 90 percent of the people who live, work, or congregate near
transmission pipelines would be covered by 2020, and 100 percent would be covered by 2030.
INGAA stated that at a minimum, all ASME/ANSI B31.8S requirements will be applied,
including mitigating corrosion anomalies and applying IM principles. Continuing to areas of less
population density, INGAA has stated they plan to apply IM principles to pipelines covering 100
percent of the potential impact radius (PIR) population32 by 2030.
However, given this level of commitment by INGAA, PHMSA has determined that it is
appropriate to consider rulemaking that would codify requirements for certain non-HCA gas
transmission pipelines to have an integrity assessment conducted on a periodic basis to monitor
for, detect, and remediate significant pipeline defects and potentially hazardous anomalies.
Requirements for data analysis, assessment methods, and immediate repair conditions would
likely be similar to requirements for HCA segments. In order to achieve the desired outcome of
performing assessments in areas where people live, work, or congregate, PHMSA is considering
an approach that would define a new term in the code: a “moderate consequence area” or
MCA.33 The definition would likely be based on the same methodology as HCAs as specified in
§ 192.903, but with more specific criteria, so that most persons that live or work within the PIR
of a pipeline benefit from the protection of mandatory integrity assessments. MCAs would
likely be used to define a subset of locations where integrity assessments are required. This
approach is proposed as a less burdensome approach for operators to identify the MCAs, since
27 Section 192.9 exempts gathering lines from Subpart O.
28 Gas distribution pipelines are subject to an IM program as prescribed in Subpart P.
29 Mileage is based upon natural gas annual reports for 2013.
30 Mileage is based upon natural gas annual reports for 2013.
31 Letter from Terry D. Boss, Senior Vice President of Environment, Safety and Operations to Mike Israni, Pipeline
and Hazardous Materials Safety Administration, U.S. Department of Transportation, dated January 20, 2012,
“Safety of Gas Transmission Pipelines, Docket No. PHMSA-2011-0023.” INGAA represents companies that
operate approximately 65% of the gas transmission pipelines, but INGAA does not represent all pipeline operators
subject to 49 CFR Part 192.
32 PIR population means pipeline mileage with people living, working, or congregating within the pipeline radius of
a circle within which the potential failure of a pipeline could have significant impact on people and property. The
PIR is calculated in accordance with § 192.903 based upon the pipeline diameter and MAOP. More discussion on
the use of a PIR approach for determining class location can be found in Section 3.7.2.
33 MCA definition, assessment, and remediation standards are in the notice of proposed rulemaking (NPRM) for the
gas integrity verification process (Gas Rule).
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gas transmission operators must already have performed the analysis in order to have identified
the HCAs, or verify that they have no HCAs. In addition, the MCA definition would include
locations where interstate highways, freeways, expressways, and other principal 4-lane arterial
roadways are located within the PIR. This additional MCA criterion is intended to meet the
intent of National Transportation Safety Board (NTSB) Recommendation P-14-1.
The above approach conforms with the INGAA commitment to conduct integrity assessments
that cover 100 percent of the PIR population, as well as Congressional directives to consider
effective and efficient options for decreasing risks to an increasing number of people living or
working in proximity to pipeline facilities. PHMSA estimates that approximately 39,000 miles
of pipeline would meet the MCA definition. However, PHMSA acknowledges that operators
have already incurred costs where operators are already conducting assessments beyond what is
required under 49 CFR Part 192. Because significant non-HCA pipeline mileage has been
previously assessed in conjunction with an assessment of HCA segments in the same pipeline,
PHMSA would consider allowing the use of those prior assessments for non-HCA segments,
provided the assessment was conducted in accordance with an integrity assessment required by
49 CFR Part 192, Subpart O. As a result, PHMSA estimates that approximately 7,400 miles of
pipeline would need an initial integrity assessment (i.e., has not been previously assessed in
conjunction with an HCA assessment).
PHMSA is considering requiring that pipeline segments in MCAs be assessed within 15 years
and every 20 years thereafter. PHMSA believes this to be a reasonable timeframe for
reassessments, given the large amount of pipeline assessments that would be required.
Currently, § 192.485 prescribes remedial measures that are required to be implemented when the
pipeline has lost strength due to corrosion and § 192.711 prescribes general requirements for
repair procedures. For non-HCA segments, the existing rule requires that permanent repairs be
made as soon as feasible. However, no specific repair criteria are provided and no specific
timeframe or pressure reduction requirements are provided. PHMSA believes that more specific
repair criteria based upon class location are needed for pipelines not covered under the IM rule.
PHMSA would also propose to require that specific conditions (i.e., repair criteria) be
remediated, to identify the timeframe within which repairs must be made, and to require a
reduction of operating pressure for conditions that present an immediate hazard. Further,
PHMSA believes that such repair criteria should be similar to, and based upon, comparable
repair criteria for HCAs, but that time frames for non-immediate conditions be relaxed. PHMSA
believes that establishing these non-HCA segment repair conditions are important because, even
though they are not within the defined high consequence locations, they could be located in
populated areas and are not without consequence. For example, as reported by operators in the
2013 annual reports, while there are approximately 20,000 miles of gas transmission pipe in
HCA segments, there are approximately 65,000 miles of pipe in Class 2, 3, and 4 populated
areas. PHMSA believes it is prudent and appropriate to include criteria to assure the timely
repair of potentially hazardous pipeline defects in non-HCA segments. These changes would
ensure the prompt remediation of anomalous conditions, while allowing operators to allocate
their resources to HCAs on a higher priority basis. In addition, PHMSA proposes to prescribe
more explicit requirements for in situ
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evaluation of cracks and crack-like defects using in-the-ditch tools whenever required, such as
when an ILI, SCC direct assessment, pressure test failure, or other assessment identifies
anomalies that suggest the presence of such defects. Cracking defects would need prescribed
evaluation criteria to establish any required replacements, repairs, and future reassessments.
PHMSA believes that establishing requirements for non-HCA segment integrity assessments and
associated repair conditions is important because, even though such segments are not within
defined HCA locations, they could be located in populated areas and incidents would still have
serious consequences. These changes would facilitate the prompt identification and remediation
of potentially hazardous defects and anomalous conditions that could potentially impact people,
property, or the environment, commensurate with the seriousness of the defect, while allowing
operators to allocate their resources to high consequence areas on a higher priority basis. Which
selected IM requirements should apply to MCAs would be a topic PHMSA would explore and
seek comment on.
2.4.3 Notice of Proposed Rulemaking
In accordance with the Act, Section 5(f), two NPRM proposals recently published to address 49
CFR Part 192 and Part 195, as described in the above paragraphs. PHMSA believes that this
approach for expanding selected IM program elements to locations beyond HCAs:
1. Represents a significant enhancement to public safety;
2. Continues to emphasize the priority and importance of HCA;
3. Does not require operators to incur costs where operators have already conducted
assessments beyond what is currently required under Chapter 601 of Title 49, United
States Code;
4. Is achievable and sustainable, and minimizes disruptions of pipeline product deliveries to
the public and industrial customers;
5. Represents an effective and efficient means for decreasing risks to persons living or
working in proximity to pipeline facilities; and
6. Applies repair criteria (including pressure reductions and special requirements for
scheduling remediation) that are appropriate to areas that are not HCAs.
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3. DOES EXPANSION OF IM BEYOND HCAs MITIGATE
THE NEED FOR CLASS LOCATIONS? (The Act § 5(a)(2))
With respect to gas transmission pipeline facilities, the Act requires the Secretary of
Transportation to evaluate whether applying IM program requirements to additional areas would
mitigate the need for class location requirements. Section 2 of this report addresses PHMSAs
evaluation and approach for applying selected IM program elements (i.e., assessment,
remediation, and continuing reassessment programs) to additional pipeline segments that are
outside HCAs. This section evaluates whether such expansion of IM requirements might
mitigate the need for class location requirements.
3.1 Class Locations (Background)
3.1.1 History of Class Locations
Class locations were an early method of differentiating areas along natural gas pipelines based on
the potential consequences of a postulated pipeline failure. The class location concept pre-dates
Federal regulation of gas transmission pipelines. Class location designations were previously
included in ASA B31.8-1968 version of the “Gas Transmission and Distribution Pipeline
System.” which is now known as the ASME International Standard, ASME B31.8 “Gas
Transmission and Distribution Pipeline Systems.” The class location definitions incorporated
into 49 CFR Part 192 were initially derived from the ASA B31.8 class location designations
(hereafter referred to as ASME B31.8).
The Natural Gas Pipeline Safety Act of 1968 (NGPSA) (Public Law 90-481), §3(a) required that
OPS adopt interim minimum Federal safety standards for pipeline facilities and the
transportation of gas based on State regulations. These interim standards, based on ASME
B31.8, were adopted by OPS and temporarily incorporated into the Code of Federal Regulations
as Part 190.34 The NGPSA further required that OPS develop comprehensive minimum Federal
safety standards for gas pipeline facilities and for the transportation of gas.
The first regulatory definitions of class locations were published on March 24, 1970.
35 These
definitions, with some modifications, still apply today. The minimum Federal standards were
promulgated as 49 CFR Part 192 with an effective date of March 13, 1971,
36 with class location
definitions being defined in Section 192.5. These definitions met the original ASME B31.8
definitions for Class 1 through 3 locations but added an additional Class 4 definition. The class
location is determined by counting the number of dwellings within 220 yards (660 ft.) on either
side of the pipeline centerline for a “sliding mile37.” Table 3-1 compares the definition of class
34 Federal Register (33 FR 16500, November 13, 1968).
35 Federal Register (35 FR 5012, March 24, 1970).
36 Federal Register (35 FR 13248, August 19, 1970).
37 The “sliding mile” is a term that counts the number of dwellings in a mile distance (moving or sliding mile) to
determine the number of dwellings in the class location unit. Section 192.5 of the Gas Code takes segments out of
the “sliding mile” for class location determination, if there are no other dwellings in the remaining portions of the
mile (Cluster).
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locations in Part 192 with the original and current definitions in ASME B31.8. Pictorial
examples of each Class location are shown in Figures 3-1 through 3-4.
Table 3-1
Historical Comparison of Class Location Unit38 Definitions
Class
Location Part 192 Definition
Original and
Current ASME
B31.8 Definition39
Current ASME B31.8
Definition40 for “Class
Location Changes"
1
Any class location unit that has 10 or
fewer buildings intended for human
occupancy
0 to 10 Buildings
Intended for Human
Occupancy (BIHOs)
11 to 25 BIHOs
2
Any class location unit that has more
than 10 but fewer than 46 buildings
intended for human occupancy.
11 to 45 BIHOs
26 to 45 BIHOs; (MAOP = 0.8 x
test pressure but < 72% of specified
minimum yield strength (SMYS)).
46 to 65 BIHOs; (MAOP = 0.667 x
test pressure but < 60% of SMYS).
3
Any class location unit that has 46 or
more buildings intended for human
occupancy.
46 or more BIHOs 66 or more BIHOs
3
An area where the pipeline lies within
100 yards (91 meters) of either a
building or a small, well-defined outside
area (such as a playground, recreation
area, outdoor theater, or other place of
public assembly) that is occupied by 20
or more persons on at least 5 days a
week for 10 weeks in any 12-month
period. (The days and weeks need not be
consecutive.).
Pipelines near places of public
assembly or concentrations of
people, such as churches, schools,
multiple dwelling unit buildings,
hospitals, or recreational areas of
an organized nature in Location
Class 1 or 2 shall meet
requirements for Location
Class 3.
4
Any class location unit that has where
buildings of 4 or more stories above
ground are prevalent.
NA Where multistory buildings are
prevalent
38 As defined in § 192.5, a “class location unit” is an onshore area that extends 220 yards (200 meters) on either side
of the centerline of any continuous 1-mile (1.6 kilometers) length of pipeline.
39 ASME B31.8-2010, Section 840.2.2 outlines class location definitions for Design, Installation and Testing.
ASME B31.8 is presently an industry consensus standard. 49 CFR Part 192 contains the Federal regulations for
class location in §§ 192.5, 192.609 and 192.611.
40 ASME B31.8-2010, Section 854 outlines class location definitions for operating and maintenance (O&M)
procedures. ASME B31.8-2007 is currently invoked by reference in Part 192. The definitions provided here were
also in the ASME B31.8-2003 version.
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Figure 3-1: Class 1 location (10 or less BIHOs) 41
Figure 3-2: Class 2 location (>10 but fewer than 46 BIHOs)
41 The red line in each pictorial represents the approximate location of the pipeline in a right-of-way (ROW).
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Figure 3-3: Class 3 location (46 or more BIHOs and well defined area - playground)
Figure 3-4: Class 4 location (Buildings with 4 or more stories prevalent)
3.1.2 Purpose of Class Locations
Class locations are used in numerous areas of Part 192 to implement a graded approach to
providing more conservative safety margins and more stringent safety standards commensurate
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with the potential consequences based on population density near the pipeline. The most basic
and earliest use of class location focused on the design (safety) margin. As standards and
regulations evolved, the use of class locations was included for many regulatory requirements in
the same manner, i.e., apply greater and more rigorous safety requirements commensurate with
the class location.
3.1.2.1 Design (Safety) Margin
Design factors, which are used in the pipeline design formula (§ 192.105) to determine the
design pressure for steel pipe, and which, generally, reflect the MAOP based upon a percentage
of the specified minimum yield strength (SMYS) that the pipeline can be operated, are based on
class locations. These design factors, from §192.111, “Design factor (F) for steel pipe”, from
§192.620, “Alternative maximum allowable operating pressure (AMAOP) for certain steel
pipelines”, and ASME B31.8 are shown in Table 3-2.
Table 3-2
Design (Safety) Factors for Steel Pipe Based on Class Location
Class Location B31.8 Design Factors Part 192 Design Factors -
§192.11142
Alternative MAOP
Design Factors -
§192.620
1 0.843 /0.7244 0.72 0.8
2 0.6 0.6 0.67
3 0.5 0.5 0.56
4 0.4 0.4 Not Applicable
Design safety factors are used in engineering calculations (Barlow’s Formula) to calculate the
design pressure and MAOP of a steel pipeline. Other pipe characteristics needed in using
Barlow’s Formula would be the pipe: diameter, wall thickness, strength (grade), seam
factor/type, operating temperature, and class location. The calculation of the design pressure for
steel pipe is outlined in § 192.105.
42 The design factors for Class 1, 2, 3 and 4 locations are in § 192.111 of the Code and are used to establish a design
pressure in Section 192.105 for determining the pipeline segments maximum allowable operating pressure
(MAOP). Design factors were an original part of the Code when it was established in late-1970. Design factors
are used so that heavier wall pipe is used in areas of greater population.
43 In ASME B31.8, Class 1, Division 1 is pipelines operating at 72% SMYS to 80% SMYS.
44 In ASME B31.8, Class 1, Division 2 is pipelines operating at less than 72% SMYS.
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Table 3-3
Design (Safety) Factors for Steel Gas Pipeline - International
Class
Location
United States
§192.111
United States
Alternative
MAOP
§192.620
United
Kingdom45 Canada46 Australia47 ISO48
13623
1 0.72 0.8 0.72/0.5 0.8 0.8049 0.8350
2 0.6 0.67 0.72/0.5 0.72 0.80 0.77
3 0.5 0.56 0.5/0.3 0.56 0.80 0.67
4 0.4 Not Applicable
(NA) 0.3 0.44 0.80 0.55
5 NA NA NA NA NA 0.45
Table 3-3 compares design factors used for determining the MAOPs of gas pipelines in Australia,
Canada, the United Kingdom and the United States. The above comparison in Table 3-3 shows that all of
these countries use 0.72 to 0.80 (which is the least conservative design factor) in sparsely populated and
rural areas. Canada and the United States use a similar approach for design safety factors in all class
locations. Canada requires class location surveys, increased pipe safety measures, and pipe upgrades to
the new design safety factor when the population density increases to new class locations – mainly when
the class changes from 1 to 3 or 2 to 4. Canada’s approach to class location changes is similar to the
United States approach. The United Kingdom uses a pipeline design system for new pipelines based
45 Class locations in the United Kingdom are called “location class 1 through 3” and are based upon risk
assessments.
46 Canada uses a class location designation similar to the United States combination of §§ 192.111 and 192.620.
Canada requires class location surveys, pipe safety measures, and pipe upgrades to the new design safety factor
when the population density increases to new class locations – mainly when the class changes from 1 to 3 or 2 to
4.
47 Australia uses a class location designation of R1 (rural), R2 (semi-rural), T1 (residential), and T2 (high rise)
which are similar to the United States Class 1, 2, 3, and 4 designations.
48 The International Standard Organization (ISO) is an international code similar to ASME B31.8 for gas pipeline
design, construction, and O&M.
49 The Australian code would require increased pipe thickness based upon a review of operational threats in both
rural and residential areas. A pipeline with a wall thickness of 8.02 millimeters may require a thickness of 11.8
millimeters after an engineering analysis of safety threats such as: pressure containment, penetration resistance,
critical defect length, stress and strain, running fracture, special construction criteria, constructability of the
pipeline, and ability to achieve adequate fatigue life.
50 ISO 13623 class 1 location is for tundra and desert areas.
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upon 0.3 or 0.5 for pipelines using “proximity pipe” (i.e. pipe having a nominal wall thickness less than
19.1 millimeters (0.752 inches)). The United Kingdom uses a higher design factor but not exceeding
0.72, when justified by a risk analysis as part of a safety evaluation. Australia, which has significantly
smaller pipe diameter infrastructure than the United States, uses a starting design factor of 0.80 for all
class locations, but requires a pipeline threat study along the pipeline route and location specific design
factors based upon the threats (population density, third party damage, external loads, etc.) to the pipeline.
The pipeline operator would have to identify the controlling load at any location along the pipeline and to
adjust the pipeline thickness (upwards) to a value sufficient to control that additional load.
3.1.2.2 Test Pressure to Establish Maximum Allowable Operating Pressure
For steel pipelines operated above 100 psi, §192.619, “Maximum allowable operating pressure:
Steel or plastic pipelines” specifies the test pressure as a multiple of MAOP. Test factors are
based on class location and are shown in Table 3-4.
Table 3-4
Test Pressure Factors to Establish MAOP for Steel Pipelines
Class location Installed before
(Nov. 12, 1970)
Installed after
(Nov. 11, 1970)
Converted under
§192.14
Alternative
MAOP (80%
SMYS)
§ 192.620
1 1.1 1.1 1.25 1.25
2 1.25 1.25 1.25 1.50
3 1.4 1.5 1.5 1.50
4 1.4 1.5 1.5 Not Applicable
3.1.2.3 Mainline Block Valve Spacing
Each gas transmission line, other than offshore segments, must have sectionalizing block valves. The
spacing for the valves is based on the class location, as specified in §192.179, “Transmission line valves.”
Each point on the pipeline must be no more than the spacing shown in Table 3-5.
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Table 3-5
Mainline Block Valve Spacing Based on Class Location
Class Location Block Valve Spacing
1 10 Miles (20 miles between valves)
2 7 ½ Miles (15 miles between valves)
3 4 Miles (8 miles between valves)
4 2 ½ Miles (5 miles between valves)
3.1.2.4 Various Other Requirements
In addition to design factors, MAOP, test pressure, and valve spacing, the use of class locations is deeply
embedded in 49 CFR Part 192 for other requirements related to design, construction, operation, and
maintenance, either directly or indirectly. To discontinue or significantly alter the existing usage of class
locations would impact 12 of the 16 subparts and 28 sections of these subparts contained in 49 CFR Part
192. Multiple sections within those subparts that would be impacted due to a class location change are as
follows:
• § 192.5 – Class Locations
• § 192.8 – How are onshore gathering lines and regulated onshore gathering lines determined?
• § 192.9 – What requirements apply to gathering lines?
• § 192.65 – Transportation of pipe
• § 192.105 – Design formula for steel pipe
• § 192.111 – Design factor (F) for steel pipe
• § 192.123 – Design of plastic pipe
• § 192.150 – Passage of internal inspection devices
• § 192.175 – Pipe-type and bottle-type holders
• § 192.179 – Transmission line valves
• § 192.243 – Nondestructive testing – girth welds
• § 192.327 – Depth of cover
• § 192.485 – Remaining strength and remedial measures
• § 192.503 – General requirements
• § 192.505 – Strength test requirements for steel pipeline to operate at a hoop stress of 30 percent
or more of SMYS
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• § 192.609 – Change in class location: Required study
• § 192.611 – Class change: Confirmation/revision of MAOP
• § 192.613 – Continuing surveillance
• § 192.619 – MAOP determination
• § 192.620 – Alternative MAOP
• § 192.625 – Odorization
• § 192.705 – Patrolling
• § 192.706 – Leakage surveys
• § 192.707 – Line Markers
• § 192.713 – Permanent field repairs of imperfections/damages
• § 192.903 – High Consequence Area – Method 1
• § 192.933 – Integrity assessments of anomalies
• § 192.935 – What additional Preventive and Mitigative (P&M) measures must an operator take?
In addition, multiple code sections within the subparts would be indirectly impacted.
3.1.2.5 Changes in Class Location Due to Population Growth
A class location can change as population grows and more people live or work near the pipeline.
When a class location changes and the MAOP is not commensurate with the present class
location, current regulations require that pipeline operators either:
• Reduce the pipe's MAOP to reduce stress levels in the pipe;
• Replace the existing pipe with pipe that has thicker walls or higher yield strength to yield
a lower operating stress at the same MAOP; or
• Where the class location is changing only one class rating (one class bump), such as from
a Class 1 to Class 2 or Class 2 to 3 location, the code requires a pressure test at a higher
test pressure, if the pipeline segment has not previously been conducted at the higher
pressure51, see § 192.611. In this example case the pipeline segment would not require
change out with new pipe, but the existing design factor of 0.72 for a Class 1 location
would be acceptable for a Class 2 location.
It is this requirement to change-out the pipe, re-pressure test, or de-rate pipe to a lower MAOP
when population growth occurs that is one of the most significant reasons that operators strongly
advocate eliminating class locations. Operators contend that they should not have to change out
pipe when a class location change occurs if the operator can prove that the pipe segment is fit for
service. PHMSA acknowledges that the class location change regulation predated development
51 For a Class 1 to Class 2 location change to meet § 192.611, the pipeline segment would require a pressure test to
1.25 times the MAOP for 8 hours. The pressure test would allow the MAOP for the existing pipeline segment to
be 0.8 times the test pressure for a Class 1 to Class 2 location change.
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of modern pipeline inspection technology such as inline inspection, above ground surveys, and
modern integrity management processes.52
At the time, it was logical to replace a pipeline when population growth resulted in a class
location change in order to restore the safety margin appropriate for that location, because the
industry did not have the technology that is available today to learn the in situ material condition
of the pipe. Also, the operator would need to use inspection technology to ensure the pipe has
the correct wall thickness, strength, seam condition, toughness, no cracking or corrosion in the
pipe body or seam, and a pipe coating that has not deteriorated or shields cathodic protection
currents or allows corrosion or cracking issues such as stress corrosion cracking.
Under current pipeline safety regulations, an operator may have to replace pipe if a population
increase triggers a change in class location. Operators may remove some pipe and pipe coatings
that are in good condition. In some circumstances, replacing a line in good condition may not
necessarily make the public safer and could divert maintenance resources from correcting more
imminent threats to integrity. In many cases the pipeline may be in good “condition,” but it
does not have the strength requirements that add that extra level of safety for the higher
population density area and the MAOP of the pipeline.53PHMSA acknowledges that application
of modern IM assessments and processes might be an alternative to pipe change-outs as a logical
outgrowth of the implementation of the integrity management rule. PHMSA further
acknowledges that its approach to requiring integrity assessments to a significant portion of non-
HCA pipe could further support consideration of such changes. PHMSA also is concerned that
some of the issues that result in pipeline failures are pipe material, pipe seam, pipe toughness,
coating quality, construction practices, and operational maintenance threats that are not properly
assessed and mitigated by operators,
54 whether due to lack of technology or other causes.55
52 Both the Canadian and Australian natural gas pipeline codes require a review and possible change-out of pipe,
lowering of MAOP’s, relocation of the pipeline, or assessment and mitigation of threats to the safe operation of
the pipeline when the population density increases near the pipeline.
53 The PIR in Integrity Management (IM) does not give any criteria to establish the pipelines operating pressure,
anomaly repair criteria, safety surveys for leaks, 3rd party encroachments, etc. When Class locations change
(additional dwellings for human occupancy) from one-level to a higher level there are cut-offs levels that may
require a different design factor, pressure test, or maintenance criteria. For pipe to be replaced the class location
change would have to be from a Class 1 to 3 or Class 2 to 4, which is a large increase in dwellings along the
pipeline.
54 PHMSA has met with operators constructing new pipelines on several occasions to discuss issues found during
inspection. In an effort to reach out to all member of the pipeline industry, PHMSA hosted a workshop in
collaboration with our State partners, the Federal Energy Regulatory Commission (FERC) and Canada’s National
Energy Board (NEB) in April 2009. The objective of the workshop was to inform the public, alert the industry,
review lessons learned from inspections, and to improve new pipeline construction practices prior to the 2009
construction season. This website makes available information discussed at the workshop and provides a forum in
which to share additional information about pipeline construction concerns. This workshop focused on transmission
pipeline construction. A workshop to address distribution pipeline construction was held in April 2010.
http://primis.phmsa.dot.gov/construction/index.htm
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3.1.2.6 Class Location Change Special Permits
Operators have applied for special permits (a type of limited regulatory waiver) to prevent the
need for pipe replacement or pressure reduction after a class location changes. Based on certain
operating safety criteria and periodic integrity evaluations, PHMSA has approved about 15class
location special permits.,56 As population growth has occurred, resulting in class location
changes in areas where the operator, through modern integrity assessment techniques believes
the pipe is in sound condition, PHMSA began to receive more requests for class location special
permits.
Provided the operator submits an acceptable application for a special permit,
57 and provided
certain conditions are met, PHMSA may consider waiving compliance with the confirm or revise
requirements following a class location change for specific natural gas transmission pipeline
segments. If granted, the special permit allows the operator to continue to operate each special
permit segment at its current MAOP based on the previous class location. The typical
considerations for an operator to receive a special permit that waives the class location
requirements were published in the Federal Register.58 Figure 3-5 provides a sample of a portion
of the criteria for approving class location change special permits. The complete class location
review table and criteria is available online at:
http://primis.phmsa.dot.gov/classloc/docs/ClassChangeWaiverCriteria.pdf.
Figure 3-5 outlines considerations for “probable acceptance” of a class location special permit
based on pipelines that were constructed with post-1980 materials and construction practices,
and that have been continually operated and maintained using post-1980 operating and
maintenance practices. Most class location special permit applications received by PHMSA
55 In 2012 on gas transmission pipelines there were a reported 112 incidents. The incidents were as follows: (1)
material/weld/equipment failure – 47 incidents (42%), (2) corrosion – 25 incidents (22%), (3) excavation damage –
12 incidents (11%), (4) other outside force damage – 6 incidents (5%), (5) incorrect operation – 5 incidents (5%), (6)
natural force damage – 6 incidents (5%), and (7) all other causes – 13 incidents (11%).
56 The special permit conditions were implemented to mitigate the causes of gas transmission incidents (serious and
significant). The special permit conditions were designed to require the operator to conduct additional inspections
and mitigate integrity issues on the special permit pipeline segment. The conditions are based upon the type
threat. The conditions are more heavily weighted on identifying: material, coating and girth weld issues, pipe wall
loss, depth of pipe cover, third party damage prevention such as marking of the pipeline and pipeline right-of-way
patrols, pressure tests and documentation, data integration of integrity issues, and reassessment intervals.
57 Administrative work for a special permit to prepare annual reports and 5-year renewals which would be
approximately 80 hours a year – at $150/hour = $12,000 per year. PHMSA has not developed an information
collection process on the administrative costs for a special permit approval, but we have estimated, based on
subject matter expert (SME) input that it would cost an operator approximately 200 labor hours and for a 30-inch
diameter class location special permit would save the operator approximately $3,000,000 per mile in capital costs.
58 Federal Register (69 FR 38948, June 29, 2004). Additional guidance is provided online at:
http://primis.phmsa.dot.gov/classloc/index.htm. Public notices were published in Federal Register: 69 FR 22115
and 69 FR 38948, dated April 23, 2004 and June 29, 2004: Docket No. RSPA-2004-17401 - Pipeline Safety:
Development of Class Location Change Waiver (Special Permit).
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have been for pipeline segments with pre-Part 192 Code pipe materials, coatings and
construction techniques (pre-1970). The criteria and approach of evaluating and possibly
approving class location special permits was for PHMSA to evaluate technical methods in the
form of special permit conditions that could be used to maintain safety in these class location
change areas. PHMSA has gotten a majority of class location special permit requests from
pipeline operators for pipeline segments in the “possible acceptance” and “requires substantial
justification” criteria areas.
Figure 3-5: Sample Class Location Waiver Criteria
3.2 ANPRM: Safety of Gas Transmission Pipelines
On August 25, 2011, PHMSA published an Advance Notice of Proposed Rulemaking (ANPRM)
to seek comments on revising the pipeline safety regulations applicable to the safety of gas
transmission and gas gathering pipelines. At that time, PHMSA requested comments on whether
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existing HCA criteria should be revised to potentially include more mileage or whether IM
program requirements should be strengthened or expanded beyond the HCAs.59
Some comments received in response to that ANPRM directly relate to whether the need for
class locations is mitigated by expansion of HCAs. The comments received on this topic are
summarized as follows:
From State Representatives:
The National Association of Pipeline Safety Representatives (NAPSR) suggested that PHMSA
eliminate IM requirements and instead require all transmission pipelines to meet Class 3 and 4
location requirements. NAPSR suggested that alternatively, PHMSA should revise HCA criteria
to include all Class 3 and 4 locations and segments that could affect critical infrastructure.
The Jersey City, New Jersey Mayor's office submitted a petition for rulemaking dated March 15,
2012, contending that the current class location system “does not sufficiently reflect high density
urban areas, as the regulations fail to contemplate either (1) the dramatic differences in
population densities between highly congested areas and other less dense class 4 locations, or (2)
the full continuum of population densities found in urban areas themselves.” Based on this,
Jersey City petitioned PHMSA to add three (3) new class locations, which would be defined as
follows:
• A Class 5 location is any class location unit that includes one or more building(s) with
between four and eight stories; (design factor - 0.3);
• A Class 6 location is any class location unit that includes one or more building(s) with
between 9 and 40 stories; (design factor - 0.2); and
• A Class 7 location is any class location unit that includes at least 1 building with at least
41 stories. (design factor - 0.1)
The Alaska Natural Gas Development Authority stated that their experience has shown that
improved pipeline design and construction requirements are needed to assure pipeline integrity.
The Authority also commented that design requirements need to accommodate likely changes in
class location, noting that explosive growth in some Alaska areas has resulted in certain class
locations rapidly changing from Class 1 to Class 3 locations.
From the Public:
A comment from the public suggested that PHMSA revise the IM requirements to potentially
include more mileage (e.g., include entire Class 3 and 4 area in lieu of only the potentially
impacted area inside Class 3 & 4) and critical infrastructure. The commenter further stated that
PHMSA should expand IM principles to non-HCA areas, improve public awareness and
involvement in HCAs, make maps publicly available, redefine class locations for high population
areas, clarify Class 4, and establish a Class 5.
The same commenter suggested that IM plans for densely populated areas (Class 4) and for a
new Class 5 encompassing cities with population greater than 100,000, be developed in
59 Federal Register (76 FR 53086, August 25, 2011).
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From Industry: From American Gas Association
(AGA):
From American Petroleum
Institute (API):
consultation with local emergency responders. The commenter further suggested that these plans
should be available for review during the Federal Energy Regulatory Commission's
environmental impact study and should be reviewed with local authorities.
3.3 Notice of Inquiry: Class Location Requirements
3.3.1 History leading up to Request for Comments on Class Location Regulations
In August 2013, PHMSA solicited comments on whether expanding IM requirements would
mitigate the need for class locations.
60 Important questions relevant to this issue include:
1. Should PHMSA increase the existing class location design factors in densely populated
areas where building are over four stories?
2. Should class locations be eliminated and a single design factor be used, if IM
requirements are expanded beyond HCAs?
3. Should there be only a single design factor for areas where there are large concentrations
of populations, such as schools, hospitals, nursing homes, multiple-story buildings,
stadiums, and shopping malls, as opposed to rural areas like deserts and farms where
there are fewer people? If so, how should a single design factor be used?
3.3.2 Summary of Comments Received on Need for Modifying Class Locations
PHMSA received 30 comment letters.
61 Commenters provided a wide range of input. There
was no clear consensus on the approach that should be taken among stakeholders or among
individual industry stakeholders. A high level summary of input received is shown in the
bulleted list below.
Commenter Summary of Comments
• Keep class locations intact for existing pipelines.
• Allow a PIR approach to be used for new pipelines and
when class locations change.
• Class locations are imbedded in regulations and
adopting a single design factor approach would be too
complicated to implement.
• Stakeholders need to be involved before any rulemaking
is made.
• Allow operators to choose the method for design
factors, existing class locations or PIR (HCA method).
• Without class locations it is not possible to determine
regulatory status of gathering lines.
60 Federal Register (78 FR 46560, August 1, 2013).
61 Comments are available on Docket PHMSA-2013-0161.
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Commenter Summary of Comments
From APGA: • Limit to pipelines operating at > 30% SMYS.
• Revise the definition of a transmission pipeline.
From INGAA: • IM should be extended beyond HCAs. However, if
PHMSA decides to extend IM, it must examine the
effects of such a change on other sections of the
pipeline safety regulations.
• Allow the use of either existing method for determining
Class locations or PIR method.
• Revise certain operation and maintenance requirements
that may no longer be necessary given new technology
and integrity management activities.
From NAPSR: • Class locations apply to much more than integrity
management.
• They apply to design, such as valve spacing, whether
that valve is 10 miles away or 2 miles away.
• They also apply to odorization and operations, leak
surveys, patrolling.
• Class locations are a much broader concept than just
integrity management, so we do have concerns on that.
From the Iowa Utilities Board: • Keep existing class locations.
• Add additional safety to buildings outside small radius
PIRs.
From the Iowa Assoc. of
Municipal Utilities:
• New regulations would impose new and significant
costs to operators of small diameter, low pressure
pipelines.
• Revise the definition of transmission pipeline.
From Pipeline Safety Trust: • Supports applying IM beyond HCAs.
• Expand class location definitions.
• Strengthen existing IM rule.
3.4 Pipeline Advisory Committee Meeting
A meeting of the Gas and Liquid Pipeline Advisory Committees was held on February 25, 2014.
At that meeting PHMSA updated the committees on Section 5 of the Pipeline Safety, Regulatory
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Certainty, and Job Creation Act of 2011. Below is a summary of significant comments provided
by members of each committee. The transcript is available on the docket.62
Public:
To make a change from class locations would involve a major effort by PHMSA. It would to
take a lot of resources to accomplish. It would be a time consuming process and that message
needs to be made in the report to Congress. There is some strength in IM over class locations;
however, there are also some weaknesses.
NAPSR:
NAPSR supports the current class location framework and recommends that HCA definition be
expanded to cover Class 3 and 4. NAPSR believes operators still do not understand IM and do
not effectively implement it.
INGAA:
The original class location definitions in B31.8 were intended to provide an increased margin of
safety for locations of higher population density. INGAA is committed to extending IM beyond
HCAs. IM is a much better risk management tool than class locations and INGAA desires to
apply integrity management because it’s much more sophisticated and deliberate and intensive
and successful than class locations. Where does it make sense to get rid of pipe replacement?
This was part of the cost/benefit justification of the IM rule in 2003. To change the class
location criteria for existing pipe would be extremely problematic for everybody and it is not
worthwhile. INGAA supports developing a standard for new construction based on an IM
approach (PIRs and HCAs), without applying it retroactively to existing pipe. Such an approach
would still require a rewrite of the code.
AGA:
AGA does not support the revision and replacement or complete removal of class locations or
the addition of new class locations without fully evaluating the impact (both to the operators and
their systems) of the many code sections that would require substantial revision. AGA supports
the development of a parallel approach, such as the IM PIR method, to alleviate pipeline
replacement or pressure reductions when class locations change. AGA members encourage
PHMSA to fully develop and understand the potential impact of expanding IM prior to any
attempt to eliminate or modify the current class location methodology.
Industry – Pipeline Operators:63
Thirty to forty percent of annual budget is spent on class location changes when that pipe is not
what needs attention. When we run ILI tools through those pipelines, those are not the areas that
we would be out repairing based on those results. Industry believes that the effect of the rules
that apply when class location changes is to divert resources to activities that, in industry’s view,
62 Docket No. PHMSA–2009-0203 can be downloaded from: regulations.gov.
63 Pipeline operators comments in addition to the trade organizations listed above can be reviewed on Docket
PHMSA-2013-0161 at regulations.gov.
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do not benefit public safety.64 IM is superior to existing rules for dealing with class location
changes. That is the right path forward. Class locations establish a baseline for the construction
of new pipelines and makes construction of new pipelines easier. Using class locations in
combination with HCAs is an optimal hybrid system that would work.
3.5 Class Location Workshop
On April 16, 2014,
65 PHMSA sponsored a Class Location Workshop to solicit comments on
whether applying the gas pipeline IM program requirements beyond HCAs would mitigate the
need for gas pipeline class location requirements. Presentations were made by representatives of
PHMSA, the National Energy Board of Canada (NEB), NAPSR, pipeline operators, industry
groups, and public interest groups. Summaries of those presentations are provided below.66
PHMSA:
The presentations made by PHMSA described the purpose of class locations and integrity
management HCAs, giving examples of how the two methods are applied to gas transmission
pipelines. A brief discussion was given on candidate alternatives to class locations. (These
alternatives are discussed in Section 3.7 of this report.)
National Energy Board of Canada:
The representative of the NEB compared the Canadian approach to class locations to how they
are applied in the United States through the Code of Federal Regulations. However, this did not
represent an official NEB position on class locations. The Canadian Standards Association
standard number CSA Z662 is the Canadian equivalent to 49 CFR Parts 192 and 195 for the
design, operation and maintenance of gas and oil pipelines, respectively. He expressed the view
that the Canadian class location rules could be “creatively misinterpreted” and were not as
prescriptive as the 49 CFR 192.5 requirements. There were conflicting definitions within CSA
Z662 for the same class location designation, and the Canadian class location designation might
not consistently represent failure consequences.
NAPSR:
NAPSR stated that the safety management system approach being developed is a “holistic”
approach that takes into account NAPSR’s concerns with IM. The presentation focused heavily
on the impact of expanding IM program requirements to pipelines in rural areas that are
inspected by state regulators. The presenter pointed out that PHMSA provides no financial
support for state inspections in rural areas and that rulemaking should be prompt to minimize
industry and regulatory confusion and allow for focused training.
Iowa Utilities Board:
Iowa Utilities Board indicated that eliminating class locations would require a major rewrite of
49 CFR Part 192, O&M manuals, revisions to state laws and regulations, and revisions of
64 Note: The commenter did not provide specific details or examples.
65 Federal Register (79 FR 16421, March 25, 2014).
66 Meeting presentations are available online at: http://primis.phmsa.dot.gov/meetings/MtgHome.mtg?mtg=95.
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standards that include class location. Adding additional class locations has similar burdens as
eliminating them. Considerations included:
• If the design factor for additional class locations is lower than the current design factor
for Class 4 location, how will gas supply be impacted?
• For low pressure, small diameter pipelines with PIRs less than 660 feet, or 300 feet for
identified sites, class locations provides more safety. For PIRs greater than 660 feet,
class locations may provide less safety.
• If PHMSA applies IMP requirements to all Class 3 and 4 locations, it should allow
operators to determine class location using either the current method or the PIR approach.
If class location is based on the PIR approach, should an additional safety factor be
applied to account for consequences outside of the PIR, as occurred in San Bruno, CA?
INGAA:
INGAA considered that the current requirements for class location change are resulting in the
replacement of good pipe. The special permit process is onerous,67 essentially eliminating it as
an option. The special permit process should be embedded into the Code. An alternative to the
current class location determination should be allowed for new construction. 68 An alternative
would be to integrate with the integrity management/PIR approach. A single design factor of
0.72 should be allowed with a different design factor for special areas (identified sites).
AGA:
AGA focused on the impact of changing class locations on a large distribution company with
pipeline classified as gas transmission. Applying the current class location change requirements
can be expensive – in excess of $1 million per change. The current waiver/special permit
process for current class location changes is very burdensome, the renewal process is
increasingly more complex, and the outcome is uncertain. AGA suggested the elimination of the
67 INGAA states that the special permit process is onerous, but submits the special permit conditions as the
bifurcated approach categories (page 39) of requirements for existing pipelines when the class location changes to
a lower class location, such as Class 1 to 3, Class 1 to 4, or Class 2 to 4 highlighted on pages 39, 40 and 41 of this
report. PHMSA implements the special permit requirements found in 49 CFR § 190.341 when reviewing and
granting a special permit.
68 The Class location special permit process was developed from integrity management concepts. PHMSA
published the special permit matrix criteria on the Federal Register (69 FR 22115 and 69 FR 38948) on April 23,
2004 and June 29, 2004: Docket No. RSPA-2004-17401 - Pipeline Safety: Development of Class Location
Change Waiver (Special Permit). The public meeting and special permit process can be found at:
http://primis.phmsa.dot.gov/classloc/meetings.htm. Appendix B-1 through 10 of this report has documents
developed to evaluate class location special permits. Since the Class location special permits are mostly reviewed
for older pipelines that may have manufacturing, construction, or on-going maintenance issues, such a seam
cracking, pipe body cracking, poor external coating, insufficient soil cover, lack of material records, dents, or
anomaly repairs not made to design safety factors that may impair the pipeline and diminish public safety,
PHMSA believes that the present overall special permit conditions and process methods are consistent with public
safety and should not be changed. PHMSA does make modifications to the special permit conditions when it is in
the interest of public safety to do so. There have been over 15 special permits for class location changes issued
since June 29, 2004 by PHMSA to Gas Transmission Pipeline Operators.
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special permit process for class location changes and incorporate specific requirements for
special permits into 49 CFR Part 192. AGA recommended two approach methods, one based on
IM and the other using the current class location approach. AGA considered that changing the
way class locations are determined is very complex, as it is deeply embedded in the current
regulations.
APGA:
APGA suggested that IM requirements should not be extended outside of HCAs, as this does not
make sense for municipal utilities. A major change to how class locations are determined would
require a major rewrite of the Code. There are only 56 publically-owned transmission lines out
of 1000 gas transmission pipeline operators. APGA would like to see a revision to the definition
of transmission lines to eliminate low pressure, small diameter pipelines operating at low stress
levels. Many publically owned “transmission” pipelines are sole suppliers to metropolitan areas.
This makes complying with potential changes to IM regulations outside of HCAs problematic. If
the regulations are changed to allow use of the PIR approach, operators should have the option to
continue using the current class location method.
Gas Processors Association:
The Gas Processors Association (GPA) indicated that 41% of gathering pipelines operating at
20% SMYS in Class 1 locations or above are 4 inches or less in diameter. Class locations are
deeply embedded into the Code and the use of class locations is familiar to operators. The
current method should be retained. If the PIR approach is adopted, operators should be allowed
a choice.
Pipeline Safety Trust:
The Pipeline Safety Trust pointed out how deeply class location is embedded in the Code, and
that IM requirements and class locations overlap in densely populated areas to provide an
overlapping safety regime. In time, the older class location method can be replaced with a more
science-informed IM regulation. Incidents and data suggest there is room for improvement in
the IM regulations. Data shows higher incident rates in HCAs than in non-HCAs. Data trends
show leaks are increasing while significant incidents have stayed constant over a ten-year period.
Newer pipe (installed in 2010 and beyond) has a higher incident rate (by a factor of 2) than pipe
installed in the next highest decade. The Pipeline Safety Trust supports expanding IM program
requirements outside of HCAs using the MCA concept, but keeping the current class location
method for now.
Accufacts:
Accufacts is another public interest group. The presenter acknowledged that class locations are
embedded in the Code. He noted that less than 7% of gas transmission pipeline is in HCAs, and
that HCA mileage is decreasing, when it should be increasing based on population growth alone.
IM is highly dependent on an operator’s ability to recognize threats, assess threats, evaluate
risks, and identify HCAs. He suggested that it is hard to have confidence in IM programs. He
also suggested that the public does not want to hear about lessons learned following a tragic
incident. He noted that the San Bruno, CA incident exposed weaknesses in the operator’s IM
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program. He also suggested that the use of a PIR is clearly not appropriate for large diameter
pipelines as demonstrated by the San Bruno, CA incident. IM 1.0 has serious flaws and needs
improvement. Shifting the class location approach to IM would seriously decrease protection of
public safety. Fixing IM regulations should be PHMSA’s first priority. Accufacts wants
effective, clear regulations not complex, unenforceable regulations. The current class location
method should be retained for now and opened for public discussion after IMP 2.0 is
implemented.
Following the conclusion of the April 16, 2014, Class Location Workshop, Northern Natural Gas
(NNG) and INGAA provided additional comments on the docket.69 Summaries of the comments
are provided below.
NNG:
NNG70 suggested the creation of an alternative method for identifying class location, in that
operators be allowed to select from the existing methodology or an alternative methodology.
The alternative would rely on the concept of a “sliding class location circle” that would have a
radius of 100 yards or a distance determined by the PIR, whichever is greater. Because the
length of the class location circle would be less than one mile under the existing class location
methodology, NNG proposed alternative criteria for building counts for each class location.
NNG proposed that operators be required to state in their operating procedures which method
they use by pipeline, and that a significant change by an operator would require change
management control and notification to PHMSA.
NNG also suggested that when a change in class location occurs operators should be allowed to
consider the PIR and choose from among two methods for mitigation. This would include; (1)
keep the existing method and perform a design factor change, or (2) allow the segment to be
incorporated into the IMP as a covered segment. The second alternative would consider the
segment as if it were within a HCA (even if were not, in fact), and could either include integrity
assessments, depending on specific criteria.
INGAA:
INGAA71 supported a bifurcated approach that would retain the current class location system for
existing pipelines and would permit the use of the PIR for new or entirely replaced pipelines.
INGAA stated that this approach would retain current class location definitions and class
location pipe upgrade criteria to define the conditions for class location upgrades that have been
used for over 40 years. However, INGAA also suggested an alternative to class location
upgrades for existing pipelines that would not require the pipeline to be replaced or retested.
69 Docket ID PHMSA-2013-0161.
70 Comments by Northern Natural Gas Company concerning “Notice of Inquiry Pipeline Safety: Class Location
Requirements” (Docket No. PHMSA-2013-0161) and the April 16, 2014, Class Location Methodology Public
Workshop in Washington, D.C., dated May 27, 2014.
71 Comments of the Interstate Natural Gas Association of America on PHMSA’s Public Workshop on Class
Location Methodology, Docket PHMSA-2013-0161, dated June 10, 2014.
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INGAA also introduced an approach using the PIR to define class locations for new or entirely
replaced pipelines. Specifically, INGAA advocated the following high-level concepts:
• INGAA recommended that PHMSA consider a different approach to the current
regulations that may require a pipe replacement when a population density increase
occurs. This new approach would utilize integrity management principles.
• INGAA recommended a reassessment of the class location design criteria for new
pipelines given technological advances in design, materials, engineering and construction
(alternative class location approach).
INGAA opined that these concepts address the concerns discussed at the workshop and provide a
path forward.
INGAA also presented that:
• Population density increases should not require a pipe replacement, if the pipe can meet
certain requirements.
o An operator should not have to change out pipe when a class location change occurs, if the
operator can prove that the pipe segment is fit for service. Under current pipeline safety
regulations, an operator may have to replace pipe if a population increase triggers a change in
class location. These replacements often require operators to remove pipe that is in good
condition. Replacing a line in good condition does not necessarily make the public safer and
is not a good use of resources. The original rulemaking to address class location upgrades
based on population increases was developed in 1970 when much of the technology and
processes that are common today were not utilized or envisioned. INGAA believes that if a
pipeline segment meets certain criteria, it should not arbitrarily be replaced. Therefore, a
revision to the existing class location change-out requirements should be considered.
• Advancements in IM technology and processes have superseded the need for mandatory
pipe replacement.
o In the past, it was logical to replace a pipeline when population growth resulted in a class
location change because of the widespread belief that a thicker wall pipe would take longer to
corrode and additional force would have to be applied (such as from an excavator) for the
pipe to fail. This kind of replacement made sense then, when the industry did not have the
technology that is available today. Given current technology, pipe quality improvements, and
ongoing regulatory processes, pipeline operators can mitigate most threats without pipe
replacement.
INGAA’s proposal for class location changes for existing pipelines, including pre- and post-1970
pipelines, is summarized as follows:
• No longer require replacement if a pipe segment meets certain requirements. These
requirements could provide the safety assurance that PHMSA noted in its development of
the IM rule. Specifically, INGAA suggests that PHMSA consider the categories of
requirements, listed below, to address any potential safety concerns. PHMSA should
engage stakeholders to develop the specific requirements that support these categories.
There are many existing sources such as consensus standards that could help develop
these requirements. PHMSA’s special permit conditions are largely unworkable as a
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model for the necessary requirements, evident by the fact that no operators have applied
for class location special permits since 201072
.
INGAA proposed the following categories of requirements:
• Baseline Engineering and Record Assessment
• Girth Weld Assessment
• Casing Assessment
• Pipe Seam Assessment
• Field Coating Assessment
o Cathodic Protection
o Interference Currents Control
o Close interval survey
o Stress Corrosion Cracking Assessments
o In-line Inspection Assessments
o Metal Loss Anomaly Management
o Dent Anomaly Management
o Hard Spots Anomaly Management
• Ongoing Requirements
o Integrity Management Program
o Root Cause Analysis for Failure or Leak
o Line Markers
o Patrols
o Damage Prevention Best Practices
o Recordkeeping & Documentation
INGAA’s proposal for an alternative class location approach that retains class location for existing
pipe but permits PIR for new or replaced pipe is summarized as follows:
• INGAA asked PHMSA to consider accepting an alternative class location approach for new
pipelines. In INGAA’s proposal, the level of O&M and integrity management activities
would be determined by the usage/population density within the PIR (see Figure 3-6, below).
When a newly constructed pipeline is located in areas with relatively low usage, there would
72 Since 2010, PHMSA has publicly stated that it did not want to see future requests for special permits for older
pipelines or pipelines operating above 72 % SMYS, since it had learned all it needed from them for IM. The
majority of the class location special permit requests PHMSA received from pipeline operators were for pipelines
in the possible acceptance or requires substantial justification categories with the pipe material and construction
being completed prior to the Code, 49 CFR Part 192. The reader can refer to the Federal Register (69 FR 38948,
June 29, 2004) for more details. Additional guidance is provided online at
http://primis.phmsa.dot.gov/classloc/index.htm.
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be a corresponding set of requirements (e.g., level 1). As usage and density within the PIR
increases over time, the requirements would be adjusted accordingly.
Figure 3-6: INGAA - Figure 1: Alternative Class Location Approach Concept
• INGAA suggested that PHMSA incorporate various design, baseline, and ongoing requirements
that would fall into the levels shown in Figure 3-6, above, to accommodate the alternative class
location approach. These requirements would follow the same format as those proposed above
for class location change-outs.
• INGAA proposed categories of requirements for existing pipelines when the class location
changes to a lower class location, such as Class 1 to 3, Class 1 to 4, or Class 2 to 4:
o Design and Construction Conditions:
 New technology pipe & coating
 Construction Quality Assurance/Quality Control Processes
 Valve location, spacing, and automation
 Odorization
o Baseline Assessments:
 In-line Inspection Assessments
 Close interval survey
 Cathodic Protection
 Construction defects
 Interference Currents Control
o Ongoing Assessments:
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 Integrity Management Program
 In-line Inspection Assessments
 Stress Corrosion Cracking Assessments
 Metal Loss Anomaly Management
 Dent Anomaly Management
 Cathodic Protection
 Root Cause Analysis for Failure or Leak
 Line Markers
 Patrols
 Leakage Surveys
 Damage Prevention Best Practices
 Recordkeeping & Documentation
Summary:
Overall, the majority of stakeholder responses suggested that PHMSA not change the current class
location approach for class used for establishing MAOP and O&M surveys for existing pipelines.
Industry strongly advocates for changes to the regulations to address pipe replacement where the class
location changes. With respect class location requirements, some industry groups and operators
supported some type of bifurcated approach for new or replaced transmission pipelines.
PHMSA developed the class location special permit process from IM concepts. Since the Class location
special permits are mostly reviewed for older pipelines that may have manufacturing, construction, or on-
going maintenance issues, such a seam cracking, pipe body cracking, poor external coating, insufficient
soil cover, lack of material records, dents, or anomaly repairs not made to design safety factors that may
impair the pipeline and diminish public safety, PHMSA believes that the present overall special permit
conditions and process methods are consistent with public safety and should not be changed. PHMSA
does make modifications to the special permit conditions when it is in the interest of public safety to do
so. There have been over 15 special permits for class location changes issued since June 29, 2004 by
PHMSA to Gas Transmission Pipeline Operators.
PHMSA does not support changing the class location requirements for existing/older pipelines. PHMSA
considers a possible use of the bifurcated approach on new pipelines through use of a minimum PIR and a
maximum PIR based upon pressure and diameter to determine Class locations 1 through 4 using dwelling
counts in each class location. The minimum and maximum PIR would replace the present 660 feet radius
on each side of the pipeline centerline for determining class location.
3.6 Class Location Approach versus IMP Approach
Table 3-6 presents a breakdown of gas transmission pipeline mileage in class locations by total
class location mileage and HCA mileage. HCA mileage is a relatively small subset of pipeline
segments.
Table 3-6
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Gas Transmission Mileage by Class Location73
Class Location Total Miles % HCA Miles %
Class 1 237,804 78.5 1,600 8.2
Class 2 30,500 10.1 1,403 7.1
Class 3 33,476 11.1 15,887 80.9
Class 4 952 0.3 744 3.8
Total 302,732 100 19,634 100
Class locations and HCAs were designed for very different purposes. While class locations drive
design, construction, testing, MAOPs, and O&M requirements, HCAs were designed to simply
determine if a segment of pipeline needed to be included in an integrity management program.
HCAs may force an operator to make repairs and assessments, but are not used to establish
MAOP or perform operational inspections, repairs, and surveys. Class locations do not address
the potential reduction in safety margin over the course of time due to corrosion or other types of
pipe degradation. IM requirements and HCA calculations provide a continuing minimum safety
margin for more densely populated areas because operators are required to conduct periodic
inspections of the pipe and repair timelines are specified for the anomalies identified within an
HCA.
Class location requirements provide an additional safety margin for more densely populated
areas relative to less densely populated areas. For instance, a Class 4 location (multi-story
buildings) has a safety factor of 0.4, while a Class 2 location 11 to 45 dwellings) has a safety
factor of 0.6. Class locations are determined based on the density of dwellings using a 660foot
wide sliding mile on either side of a pipeline’s centerline. For larger diameter, higher pressure
pipelines with PIRs greater than 660 feet, the current class location methodology may not
account for all the buildings within the pipeline’s potential impact radius. For small diameter,
low pressure pipelines with a PIR less than 660 feet, the class location methodology may account
for a larger number of buildings than are within a pipeline’s potential impact radius. This is
illustrated in Figure 3-7 below, which shows PIR as a function of pipe diameter and MAOP.
(The example illustrates a pipeline with a PIR of 660 feet, which corresponds to the existing
class location unit width).
As population increases in the vicinity of the pipeline, the change in class location may require a
pressure test (at higher pressures than previously tested) or new pipe with updated safety features
to revalidate MAOP.
73 Gas Transmission Class Location Mileage (Source: 2013 Annual Report Data as of July 27, 2014).
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If the PIR approach was used instead of class location74, a pipeline with a pipe diameter greater
than 30-inch and 1000 psi MAOP would require class locations requirements to be based upon a
width greater than 660-foot wide on either side of a pipeline’s centerline as presently required.
However, because PIR would use sliding PIR instead of sliding mile, in some instances operators
may be able to more precisely apply class location requirements to the impacted outside
boundary limits of a failure or a rupture. Table 3-7 below shows gas pipeline mileage based
upon diameter. Based upon 2013 annual report data, 80,947 miles of operating pipelines are 30-
inch and greater diameter. In the past 20-years many new large diameter pipeline mileage, 30-
inch or larger diameter, have been designed and are operated at MAOP’s greater than 1000 psi.
Examples of pipelines built at larger diameters and operating pressures are the Alliance Pipeline
and Rockies Express Pipelines. These pipelines were built in the late 1990’s to mid-2000’s using
42-inch pipe and operate at MAOPs of 1440 psi or greater. A 42-inch diameter pipeline that
operates at a 1440 psi MAOP would have a PIR of 1594 feet. This would require the present
class location sliding mile to be increased from 660 feet to either 1594 feet or greater. Pipelines
with diameters less than 30-inch and MAOPs less than 100 psi would have PIRs less than 660
feet. An example is a 16-inch diameter, 800 psi MAOP, which would have a PIR of 453 feet.
For this example, class location overstates the number of buildings in the pipe’s potential impact
radius.
74 If PIR was used instead of the “sliding mile” it would still need to be on the “sliding mile” concept (sliding PIR).
The PIR distance on either side of the pipeline centerline would be used for the dwelling count instead of the
present 660-foot distance presently used in Part 192.
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1000
Class
Location Unit
Figure 3-7: PIR75 vs. MAOP and Diameter (Example for 30-inch diameter, 1000 psi
pipeline)
Table 3-7
Gas Transmission, Distribution and Gathering
Mileage by Pipe Diameter76
Pipe Diameter
(inches) ≤ 12 ˃ 12 to 28 ˃ 28 to 32 ˃ 32 Total
Mileage
Gas
Transmission
(miles)
114,083 107,253 43,312 37,635 302,283
Gas Distribution
– Mains (miles) 1,244,078 9,255 -- -- 1,253,333
75 PIR (feet) = 0.69(pressure (psi) x diameter (inches)2 )1/2
.
76 Gas Transmission, Distribution, and Gathering Mileage (Source: 2013 Annual Reports as of July 21, 2014).
Table 3-6 on page 39 of this report has a gas transmission total mileage that is 449 miles different have Table 3-7
due to reporting differences from pipeline operators on annual reports and the date of information.
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Gas Gathering
(miles) 13,161 3,737 395 136 17,429
Totals 1,371,322 120,245 43,707 37,771 1,573,045
3.7. Alternatives to Class Locations
At the April 16, 2014, PHMSA Class Location Workshop, PHMSA presented a number of
alternatives to the current method of determining class locations. The alternatives are discussed
below. The current method is based on the density of structures within a sliding mile that is 660
feet wide on either side of a pipeline centerline or a well-defined outside area,77 as defined by
§ 192.5(b)(3)(ii), within 300 feet on either side of a pipeline centerline.
3.7.1 Single Design Factor
PHMSA solicited comments78 on the use of a single design factor for all pipelines in locations
where there may be large concentrations of people, such as schools, hospitals, nursing homes,
multiple-story buildings, stadiums, and shopping malls as an alternative to the current method for
determining class locations.
The comments on the use of a single design factor were overwhelmingly negative. Commenters
felt that to mitigate class locations by going to a single design factor approach impacts too many
49 CFR Part 192 code sections, would be too complicated to implement, and may even result in
a decrease in safety.
An additional safety factor79 would likely need to be considered if this method were proposed.
3.7.2 Sliding Mile Based upon Potential Impact Radius
The current sliding mile methodology for determining a class location could be replaced by a
methodology based on a sliding potential impact radius.
PIRs are a function of pipe diameter and MAOP. Small diameter pipe with a low MAOP would
most likely have a PIR less than 660 feet. Large diameter pipe with a high MAOP, typical of
large diameter, gas transmission pipelines being constructed today, would most likely have a PIR
77 An area where the pipeline lies within 100 yards (91 meters) of either a building or a small, well-defined outside
area (such as a playground, recreation area, outdoor theater, or other place of public assembly) that is occupied by
20 or more persons on at least 5 days a week for 10 weeks in any 12-month period. (The days and weeks need not
be consecutive.)
78 Federal Register (78 FR 46560, August 1, 2013).
79 PHMSA does not believe it is in the interest of public safety to have a single design factor for all class location
areas due to the compressibility of natural gas and the likelihood of a high pressure gas transmission pipeline
rupture failure being an explosion and fire similar to the San Bruno, CA, Carlsbad, NM, and Edison, NJ pipeline
ruptures.
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greater than 660 feet. A PIR of 660 feet is equivalent to a 30-inch diameter pipe with an MAOP
of 1000 psi or greater.
NNG has proposed an alternative method to the PIR approach, calling it the class location circle
approach. A class location circle would be either 300 feet in radius or the PIR whichever is
larger. NNG also proposed specific building density criteria to be used with its proposed
approach, as follows:
• Class 1: Two or less buildings intended for human occupancy;
• Class 2: Three to eleven buildings intended for human occupancy;
• Class 3: More than eleven buildings intended for human occupancy or an identified site
within the class location circle; and
• Class 4: Three or more 4-story buildings within the class location circle.
3.7.2.1 Pros of Using a PIR Approach for Determining Class Location
• PIRs greater than 660 feet could include buildings that are currently excluded from the
class location criteria;
• A PIR approach would provide additional safety over the current methodology for PIRs
greater than 660 feet;
• The PIR approach could be tied to class location, thus minimizing required Code changes
and the impact on operators;
• If tied to IMP requirements, more repairs would be performed on the pipelines because of
the required assessments;
• If tied to IMP requirements; the amount of pipe that would have to be replaced due to a
class location change would be minimized as the true condition of the pipe would be
known through required assessments;
• Could be applied to all pipelines including gas distribution and gas gathering;
• Could be applied to all gas pipelines including steel or plastic;
• O&M functions may be reduced because they are captured by IMP requirements;
• The PIR approach may make determination of class locations easier; and
• The PIR method could be defined in a way to account for certain populated locations
(such as schools) that are not captured by the current class location definition.
3.7.2.2 Cons of Using PIR Approach for Determining Class Locations
• The PIR approach may exclude buildings (thus potentially resulting in lower class
location grades and less margins of safety at those locations) for PIRs less than 660
feet.80
• Any changes to the definition and usage of class locations in 49 CFR Part 192 will
require a very through process, since class locations affect all gas pipelines including
transmission (interstate and intrastate), gathering, and distribution pipelines.
80 Buildings could be outside the PIR and inside the 660 feet area of a class location this would change the class
location safety factor. Buildings that may be outside the PIR can still be impacted from a rupture.
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• The PIR approach does not take into account the pipe wall thickness, grade, seam type,
testing history, or design factor that is used to determine the pipeline maximum allowable
operating pressure for the class location.
•
.
• Multiple sections of the Code currently use class location for defining certain
requirements including 12 subparts and 28 sections. The sections are 49 CFR Part 192,
Subparts A, B, C, D, E, G, I, J, K, L, M, and O as described below. All would need to be
revised to reflect changes:
49 CFR Part 192 – Subparts that use Class Locations
o Subpart A – General – Class Location
o Subpart B – Materials – Pipe Wall Thickness or Grade/Strength
o Subpart C - Pipe Design – Design and Operating Pressures
o Subpart D - Design of Pipeline Component – Design and Operating Pressures
o Subpart E - Welding of Steel in Pipelines – Non-Destructive Tests
o Subpart G - General Construction – Depth of Cover
o Subpart I – Corrosion Control – Corrosion Remaining Strength and Repairs
o Subpart J - Test Requirements – Test Pressure Factor
o Subpart K – Uprating – MAOP, Test Pressure, Class Location, & Repair
o Subpart L—Operations – Class Location and MAOP
o Subpart M—Maintenance – Inspection Intervals
o Subpart O—Gas Transmission Pipeline IM – HCA Determination – Method 1
49 CFR Part 192 – List of sections impacted by Class Locations
o § 192.5 - Class Locations
o § 192.8 - How are onshore gathering lines and regulated onshore gathering lines
determined?
o § 192.9 - What requirements apply to gathering lines?
o § 192.65 - Transportation of pipe
o § 192.105 - Design formula for steel pipe
o § 192.111 - Design factor (F) for steel pipe
o § 192.123 - Design of plastic pipe
o § 192.150 - Passage of internal inspection devices
o § 192.175 - Pipe-type and bottle-type holders
o § 192.179 - Transmission line valves
o § 192.243 - Nondestructive testing - girth welds
o § 192.327 - Depth of cover
o § 192.485 - Remaining strength and remedial measures
o § 192.503 - General requirements
o § 192.505 - Strength test requirements for steel pipeline to operate at a hoop stress of
30 percent or more of SMYS
o § 192.609 - Change in class location: Required study
o § 192.611 - Class change: Confirmation/revision of MAOP
o § 192.613 - Continuing surveillance
o § 192.619 - MAOP determination
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o § 192.620 - Alternative MAOP
o § 192.625 - Odorization
o § 192.705 - Patrolling
o § 192.706 - Leakage surveys
o § 192.707 - Line Markers
o § 192.713 - Permanent field repairs of imperfections/damages
o § 192.903 - High Consequence Area - Method 1
o § 192.933 - Integrity assessments of anomalies
o § 192.935 - What additional P&M M must an operator take?
• A PIR is only applicable for flammable gases (not other toxic gases such as chlorine).
Current class location methodology is independent of product being transported;
• Criteria for class locations would need to be redefined;
• Allowing the PIR approach to be used for new pipelines and replaced pipelines may
introduce O&M regulatory complexities;
• Allowing the PIR approach to be used for new and replaced pipelines would not alleviate
one of industries major concerns with the current methodology, i.e., the replacement of
existing pipe when class locations change;
• Criteria would need to be developed to define PIR-based methods for design,
construction, testing, operations and maintenance regulatory requirements;
• O&M functions for small diameter and low pressure pipe might be lost;
• State programs rely on class location for state-specific rules;
• The regulation of gas gathering pipelines is determined by the current class location
methodology;
• It is unclear how distribution pipeline operators would deal with the change to a PIR-
based system;
• Existing methodologies for calculating the remaining strength of pipelines due to defects
could be adversely affected. Current programs rely on class location factors for safety
margins;
• Work management systems and geographic information system class calculators would
need to be revised to reflect a PIR-based system;
• It might be necessary to revisit HCA definitions, which do not necessarily include all the
pipe that would need to be included in IM using the PIR-based approach to class location;
• Implementation complexities include:
o Dealing with legacy (both pipe/material81 and construction techniques82),
grandfathered (§ 192.619(c)), low pressure tested, or untested pipelines;
81 Legacy pipe means steel pipe manufactured using techniques such as: low-frequency electric resistance welded;
direct-current electric resistance welded; single submerged arc welded; electric flash welded; wrought iron; pipe
made from Bessemer steel; or any pipe with a longitudinal joint factor, as defined in § 192.113, less than 1.0 (such
as lap-welded pipe) or with a type of longitudinal joint that is unknown or cannot be determined, including pipe of
unknown manufacturing specifications.
82Legacy construction techniques mean usage of any historic, now-abandoned, construction practice to construct or
repair pipe segments, including any of the following techniques: wrinkle bends; miter joints exceeding three
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o Methods for increasing MAOP (uprating) when using a PIR-based approach;
o Criteria for repairs and remediation outside of current HCAs;
o Dealing with undocumented material records for pipe and components;
o All existing interpretations, advisory bulletins, waivers, and special permits would
need to be reviewed for applicability and possible change or revocation; and
o Assimilation of significant change since industry understands current class locations
methodology, how it applies, and class location driven requirements.
3.7.3 Expand Class Locations
Gas transmission pipelines are currently classified Class 1, 2, 3, or 4 locations. Class 4 is
defined as buildings of 4 or more stories are prevalent. Heavily developed urban areas have
many buildings over four stories high. Pipeline Safety Trust and the Jersey City, N.J. Mayor’s
office felt additional class locations should be established for buildings over four stories tall.
The Jersey City, N.J. Mayor’s office recommended three additional Class Locations, 5 through 7,
with a sequentially lower design factor in each new class location.
Industry commenters were almost universally against adding additional class locations. They
felt that new class locations with design factors lower than the current 0.4 for Class 4 locations
would make it difficult to supply natural gas to the newly classified areas.
3.7.4 Bifurcated Approach
The bifurcated approach would keep the current class location method for existing pipelines but
add a new method using the PIR approach for new construction and replacement pipelines. This
approach would utilize a PIR approach similar to the approach discussed in Section 3.7.2 for new
or replacement pipelines only.
3.7.5 Revise §192.611 to Include Additional IM Oriented Methods for Addressing Class Location
Changes
One class location alternative to consider is to retain the current method for determining class
locations but to revise the regulations for addressing changes to class locations. Such changes
might include alternatives in addition to pipe replacement, re-pressure testing, or de-rating, such
as incorporation of integrity management practices to validate the condition of the pipe and
monitor the pipe within an integrity management process and not allowing pipe with pre-Code
pipe with probable seam or body cracking quality issues to be used in the class location upgrade.
Such an approach would essentially codify the fundamental requirements currently contained in
Class Location Special Permits, thus providing regulatory certainty.
3.7.6 No Change in Class Location Methodology
Retain the current method for determining class locations and evaluating changes to class
locations.
degrees; dresser couplings; non-standard fittings or field fabricated fittings (e.g., orange-peeled reducers) with
unknown pressure ratings; acetylene welds; bell and spigots; or puddle welds.
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4. CONCLUSION
Section 5 of the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 required the
Secretary of Transportation to evaluate— (1) whether integrity management system
requirements, or elements thereof, should be expanded beyond high-consequence areas; and (2)
with respect to gas transmission pipeline facilities, whether applying integrity management
program requirements, or elements thereof, to additional areas would mitigate the need for class
location requirements. PHMSA has evaluated this requirement through the direct solicitation of
stakeholder feedback, including industry, operator, regulatory agencies, and the public, as well as
through public meetings and workshops.
Based upon input from stakeholders, findings from incident investigations, lessons learned,
assessments, IM, and O&M, design, and construction considerations, PHMSA has concluded
that there is a sufficient basis to propose expanding selected IM program elements (i.e.,
assessments and remediation of defects on a continuing interval) be applied to additional areas
beyond HCAs. For gas transmission pipelines, the assessment and remediation requirements
would be limited to selected areas outside HCAs identified as MCAs. This integrity assessment
approach for non-HCA locations are addressed in separate NPRMs for both gas transmission and
hazardous liquid pipelines.
For gas transmission pipelines, PHMSA believes the application of integrity management
assessment and remediation requirements to MCAs does not warrant elimination of class
locations. Class locations affect all gas pipelines, including transmission (interstate and
intrastate), gathering, and distribution pipelines, whether they are constructed of steel pipe or
plastic pipe. Class location is integral to determining MAOPs, design pressures, pipe wall
thickness, pipeline repairs, valve spacing, (HCAs), and operating and maintenance inspections
and surveillance intervals. Class locations affect 12 subparts and 28 sections of 49 CFR Part 192
for gas pipelines. The subparts and sections are listed and discussed in Sections 3.1.2.4 and
3.7.2.2. While assessment and remediation of defects on gas transmission pipelines is an
important risk mitigation program, it does not adequately compensate for other aspects of class
location as it relates to other types of gas pipelines, and as it relates (for all gas pipelines) to the
original pipeline design and construction such as the design factor, initial pressure testing,
establishment of MAOP, valve spacing, surveillance intervals, and other aspects of pipeline
safety, that are based on class location. Thus, PHMSA has determined to retain the existing class
location requirements.
5. FUTURE CONSIDERATION OF CLASS LOCATION
PHMSA acknowledges that, although it has tentatively decided to retain the class location
requirements, industry raised some legitimate issues with the existing rules for implementing
class location. A significant issue relates to class location changes. Currently, § 192.611 allows
one class change (one class bump) without the operator replacing pipe when population density
near the pipeline increases. However, operators have identified that replacing pipe in locations
that change from Class 1 to Class 3 (two class bump) are very costly and submit that pipe
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replacement is not needed when effective integrity management programs are applied to this
pipe. Operators submit that safe operation of steel gas pipelines that were originally constructed
in Class 1 locations (and operate at pressures up to 72 percent SMYS) that have changed to Class
3 could be achieved using modern day IM program practices.
However, during the past seven (7) years (2007 through 2014), PHMSA has observed problems with pipe
and fitting manufacturing quality including low strength material,83 construction practices, welding, field
coating practices, IM assessments and reassessment practices84, 85 and documentation practices.86 These
problems, which included many large diameter and high pressure pipeline projects (24-inch and larger
diameter and pressures over 1000 pounds per square inch), give PHMSA pause in considering approaches
that would allow a two class bump (Class 1 to 3 or Class 2 to 4) without pipe replacement for a high
pressure gas transmission pipeline. In April 2009, PHMSA held a Construction Workshop reviewing
construction quality issues: http://primis.phmsa.dot.gov/construction/meetings.htm. PHMSA set-up a
website87 to notify operators of pipeline material strength problems found during construction inspections
and INGAA developed a white paper for pipeline operators to use in ordering pipe for new construction
projects.88 Some examples of the quality issues found on new large diameter (≥ 24-inches) pipeline
projects constructed during 2007 through 2012 were as follows:
• One major large diameter pipeline project had eight pressure test failures, two in-service failures,
and cut out over 40 defect mainline pipe bends and girth weld fit-up;
• Another major large diameter project had over 200 low strength pipe joints cut-out and replaced;
• Another major large diameter pipeline project had in-service leaks due to the poor quality of pipe
bends and girth weld fit-up; and
• Another major large diameter pipeline project had to de-rate the pipe grade due to low strength
steel and rejected over 40 pipe fittings due to low strength.
PHMSA is also in the process of developing and implementing safety management systems
(SMS) with a national consensus standards organization, in response to NTSB Recommendation
P-12-17.89 The goal of SMS is to improve management involvement at all levels to improve the
83 PHMSA has documented pipe material low strength issues through an advisory bulletin and the following web
site link http://primis.phmsa.dot.gov/lowstrength/index.htm.
84 IM and Operational procedures and practices have been issues in the Pacific Gas & Electric (PG&E) San Bruno,
CA rupture in September 2010 and the Enbridge Marshall, MI rupture in July 2010.
85 PHMSA issued Advisory Bulletins, ADB-11-01 and ADB-2012-10, concerning IM using meaningful metrics and
assessments to operators on January 10, 2011, and December 5, 2012, which can be reviewed at:
http://phmsa.dot.gov/pipeline/regs/advisory-bulletin.
86 PHMSA issued Advisory Bulletin, ADB-12-06, concerning documentation of MAOP on May 7, 2012, which can
be reviewed at: http://phmsa.dot.gov/pipeline/regs/advisory-bulletin.
87 PHMSA developed a website titled “Low Strength Pipe” to inform pipeline operators about material quality
issues, which can be reviewed at: http://primis.phmsa.dot.gov/lowstrength/index.htm.
88 INGAA issued a white paper dated September 2009 titled-
“Identification of Pipe with Low and Variable
Mechanical Properties in High Strength, Low Alloy Steels”, which can be reviewed at:
http://www.ingaa.org/?ID=10511
89 See Pipeline Accident Report NTSB/PAR-12/01, adopted July 10, 2012, Enbridge Incorporated Hazardous Liquid
Pipeline Rupture and Release Marshall, Michigan, July 25, 2010.
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quality of pipeline material, construction, operations, maintenance, and integrity management.
On February 27, 2014, July 2, 2014, and April 22, 2015, PHMSA held three workshops seeking
stakeholder input on SMS. Information on the workshops is available online at:
http://primis.phmsa.dot.gov/meetings.
PHMSA is committed to continued retrospective review of pipe replacement requirements
associated with the class locations in 49 CFR Part 192. PHMSA will continue to study and
consider if adjustments are needed to the way class locations are defined and reviewed when the
class location changes. PHMSA will continue to listen to stakeholder input and consider:
• Comments and suggested approaches submitted on the docket90;
• More efficient and practical class location approaches that improve safety and avoid
unnecessary pipe replacements where safety can be maintained with other robust
measures such as incorporating IM principles.
Any changes to the definition and application of class locations in 49 CFR Part 192 will require a
very thorough vetting process. Following publication of the final rule titled “Pipeline Safety:
Safety of Gas Transmission Pipelines;” (Docket No. PHMSA-2011-0023, RIN 2137-AE72),
PHMSA plans to further evaluate the feasibility and the appropriateness of alternatives to
address this issue, continue to reach-out to all stakeholders, consider input from all sources, and
consider future rulemaking if a cost-effective and safety focused approach to adjusting specific
aspects of class location requirements can be developed, in order to address the issues identified
by industry. In doing so, PHMSA will evaluate any alternatives in the context of other issues it is
addressing related to new construction QMS and SMS, and will also consider inspection
findings, IM assessments, and lessons-learned from past incidents. PHMSA intends to initiate a
subcommittee of the Gas Pipeline Advisory Committee to identify possible alternatives to our
current Class Location requirements, in particular to determine whether PHMSA policies for
granting Special Permits for Class Location waiver requests should be incorporated into the
pipeline safety regulations. PHMSA also plans to publish an advance notice of proposed
rulemaking in the near future to gain further information on analyzing current requirements that
result in pipe replacement and alternatives.
90 Docket No. PHMSA-2011-0023; All comments regarding the Class Location report received in response to
Docket No. PHMSA-2011-0023 will be considered during any review of the existing Class Location requirements.
Late filed comments will be considered as practicable after the comment period closes for the Pipeline Safety:
Safety of Gas Transmission Pipelines NPRM.
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Appendix A - Abbreviations
Abbreviation Description
Act of 2011 Job Creation Act of 2011
AGA American Gas Association
ANPRM Advance Notice of Proposed Rulemaking
ANSI American National Standards Institute
APGA American Public Gas Association
API American Petroleum Institute
ASA American Standards Association
ASME American Society of Mechanical Engineers
BIHO Buildings Intended for Human Occupancy
CFR Code of Federal Regulations
FR Federal Register
GPA Gas Processors Association
HL Hazardous Liquid
ILI In-Line Inspection
IMP Integrity Management Program
INGAA Interstate Natural Gas Association of America
MAOP Maximum Allowable Operating Pressure
MCA Moderate Consequence Area
NAPSR National Association of Pipeline Safety Representatives
NEB National Energy Board of Canada
NNG Northern Natural Gas
NPRM Notice of Proposed Rulemaking
NTSB National Transportation Safety Board
O&M Operations and Maintenance
OPS Office of Pipeline Safety
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PHMSA Pipeline and Hazardous Materials Safety Administration
PIR Potential Impact Radius
PSIA of 2002 Pipeline Safety Improvement Act of 2002
PSIG Pounds Per Square Inch Gauge
QMS Quality Management Systems
RSPA Research and Special Programs Administration
SMS Safety Management Systems
SMYS Specified Minimum Yield Strength
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Appendix B – Class Location Waiver Criteria
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## Provenance

- Official: Yes
- Source: <https://downloads.regulations.gov/PHMSA-2011-0023-0153/attachment_1.pdf>
- Source ID: `regulations-gov`
- SHA-256: `1bf67fafafa3e820d4fff72fd4a10d84cf018c023106718d74c29e69c261f57e`
- Retrieved: 2026-08-20T02:22:46.679Z
- Exported: 2026-08-25T07:18:01.055Z
- Document slug: `regulations-gov-attachment-0900006482028f72`

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