# U.S. DOT/RSPA - Briefing Paper on Internal Corrosion

- **operation:** document
- **citation:** 0900006480e8d3ee
- **title:** U.S. DOT/RSPA - Briefing Paper on Internal Corrosion
- **source type:** rulemaking
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** Not available
- **summary:** The paper summarizes PHMSA’s plan to issue a final rule responsive to an NTSB recommendation to require that new or replaced pipelines be designed and constructed with features to mitigate internal corrosion, and outlines changes PHMSA is considering from the NPRM (including shifting focus from avoiding liquid accumulation to reducing internal corrosion risk, excepting offshore pipelines, placing requirements with other corrosion control rules, and simplifying recordkeeping). It also discusses the rationale for not adopting certain exceptions, addresses placement within the Code, and proposes a two-fold recordkeeping concept: operators must generally maintain records demonstrating compliance and may use as-built drawings or procedures with documented variances. The paper notes committee concerns and that PHMSA will not share draft final rule text with the committee. Limitations: the text
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- **source url:** https://downloads.regulations.gov/PHMSA-RSPA-1998-4470-0235/attachment_1.pdf
**body:**

<<<PAGE 1>>>

B riefing Paper August 24, 2006
Designing and constructing gas transmission pipelines to control internal corrosion
Advisory Committee Action: Vote on proposed rule and cost-benefit analysis
Project Contact: Barbara Betsock
NTSB Recommendation:
Revise 49 Code of Federal Regulations Part 192 to require that new or replaced
pipelines be designed and constructed with features to mitigate internal corrosion.
At a minimum, such pipelines should (1) be configured to reduce the opportunity
for liquids to accumulate, (2) be equipped with effective liquid removal features,
and (3) be able to accommodate corrosion monitoring devices at locations with
the greatest potential for internal corrosion.
Past PHMSA action and advisory committee consideration:
• Following a briefing in June 2005, this committee generally supported the concept
of a regulation responsive to the NTSB. Some members expressed concern that
the regulation not be overbroad or limit protections to high consequence areas.
• PHMSA issued a Notice of Proposed Rulemaking (NPRM). (70 Fed Reg 74262;
December 15, 2005). The NPRM proposed to:
- Require design to avoid liquid accumulation, to include liquid removal
equipment, and to include monitoring. Apply the design requirement
without regard to the anticipated operations of the line.
- Include offshore pipelines and gathering lines.
- Require an operator to examine downstream portions for internal
corrosion impacts caused by changes to the upstream pipeline.
- Require documentation, including engineering analysis, for every design
decision with respect to internal corrosion control.
• PHMSA presented the NPRM and cost benefit analysis to the committee for
consideration and vote at the June 28, 2006 meeting.
- At the meeting, PHMSA committed to clarify one concern raised by the
committee with respect to a proposed requirement to analyze changes
impacting downstream facilities. The final rule will clarify that only
changes to configuration of the pipeline will require analysis.
-The committee requested additional information and postponement of the
vote. This paper and its attachments provide additional information for
the meeting and vote on August 24.
- Committee concerns unresolved at the June 28 meeting were: whether
the committee was considering a proposed rule or a draft final rule; what
type of record-keeping should apply to the regulation; and the degree of
enforceability of the regulation.
The additional information provided

<<<PAGE 2>>>

• This briefing paper includes a description of how PHMSA works with its advisory
committees on consideration of proposed rules and cost-benefit analyses.
• The description below of what PHMSA intends to do with the final rule outlines
how we intend to address the major comments to the proposed rule.
• The attached concept paper describes how we intend to approach record-keeping.
• The attached summary of major comments includes an expanded description of
comments on record-keeping, including approaches suggested by commenters.
• The attached 5 pages of excerpts from the NTSB report on the Carlsbad, New
Mexico, accident show how NTSB developed its recommendation on design and
construction of gas transmission pipeline to address internal corrosion.
Committee consideration of proposed rules and cost-benefit analyses
• The pipeline safety law requires PHMSA to seek the advice of this committee on
proposed rules and cost-benefit analyses.
• In recent years, PHMSA has made an effort to provide this committee a summary
of public comment on proposed rules and information about the position PHMSA
is likely to take vis-à-vis the major comments.
• PHMSA does not share the text of draft final rules with the committee since doing
so could trigger a new round of public comment and delay the safety benefits of
completing the rule.
What PHMSA intends to do:
• Consider carefully the comments and any advice this committee provides.
Issue a final rule responsive to the NTSB recommendation.
• We are considering issuing a final rule with the following changes from the
NPRM:
- Change focus from avoiding liquids to reducing risks of internal
corrosion. Simplify the section to conform more closely to the NTSB
recommendation. This change, which will be further explained in the
preamble, will recognize the inability to avoid low spots in every case
and the variety of pipeline environments. This change responds to
comments by INGAA, AGA, individual pipeline companies, and the
Iowa Utilities Board. Simplification will improve enforceability.
- Except offshore pipelines from the regulation. This change responds
to comments by INGAA and El Paso.
- Keep the final rule with other corrosion control requirements in
subpart I, but add a cross-reference in a design subpart of Part 192 and
clarify the non-retroactive impact of the rule. This maximizes the
safety benefit of integrated approaches to internal corrosion.
- Simplify the recordkeeping provision. This responds to comments
by INGAA, AGA, the Texas Pipeline Association, individual pipeline
companies, and this committee.

<<<PAGE 3>>>

Concept for Addressing Record-keeping in Final Rule on
Designing and constructing gas transmission pipelines to control internal corrosion
Use the approach developed in negotiated rulemaking for operator qualification
regulations. This two-fold approach would:
1. Require an operator generally to maintain records demonstrating compliance with
the section; and
2. Add some specificity on the required records.
For the specificity, allow an operator to use as-built drawings and other construction
records or written procedures. Preamble language will provide examples. One example
is a procedure on how an operator will address design following the contour of the land in
design. To avoid accumulation of liquid in the low spots, the procedure might call for
incorporating design feature to maintain gas velocity or turbulence or to remove liquids.
The actual construction records or as-built drawings would show what an operator
actually did. Another example might be a construction record showing the use of a filter
or separator at the gate station of a distribution pipeline. Regardless of the choices in
record-keeping an operator makes, the records must show circumstances justifying
variance based on impracticability or lack of necessity. For example, if an operator does
not provide features for effective liquid removal at low spots, the records must show why
it is not necessary to do so.

<<<PAGE 4>>>

Summary of major comments and how we are addressing them
Request for exceptions from regulation based on expected operations
Many commenters requested an exception to the design and construction requirements if
the operator believes liquids will not pose a problem in the line. The commenters
suggested several variations, including:
• except pipeline from the requirements where an operator confirms liquids will not
present an uncontrolled threat (INGAA);
• require design and construction actions only where corrosive gas is being
transported (AGA);
• except pipelines in areas without a history of internal corrosion (Iowa).
Response: When an operator knows liquids in the pipeline are likely, relying on
operation and maintenance actions alone to address internal corrosion misses the safety
and economic benefit of advance planning for future needs. An operator cannot predict
with any certainty the absence of corrosive gas in upset conditions. Planning for these
upset conditions when making design and construction decisions makes sense from a
safety perspective since it facilitates future operation and maintenance actions to address
internal corrosion.
For cost effectiveness, PHMSA is considering adding more flexibility to operators to
select design and construction options fitting the relative risk that the pipeline will
transport corrosive gas in the future.
Other requested exceptions from regulation
Commenters requested, without explanation, exceptions for the following pipeline
facilities addressed by the proposed rule:
• gathering lines (INGAA, El Paso);
• offshore lines (INGAA, El Paso); and
• compressor stations (Duke).
Response: PHMSA agrees with an exception for offshore lines. Although these pipelines
experience internal corrosion, the risk they pose to people and property is considerably
less. In addition, the design and construction options are more limited.
Gathering lines and compressor stations are different. Gathering lines are only regulated
in populated areas. By their very nature, gathering lines regularly transport gas
containing liquids. Both historically and in the new gathering line regulation, gathering
lines are subject to the same design and corrosion regulations as transmission lines.
Compressor stations do not operate well when there are liquids in the gas flow and liquid
removal may result in liquid accumulation in compressor station piping. The incident
statistics indicate the real risk of internal corrosion with respect to both gathering lines
and compressor stations.

<<<PAGE 5>>>

Placement within Code
Several commenters suggest Subpart I- Requirements for Corrosion Control is wrong
place for the proposed rule. They suggest various combinations of Subpart C - Pipe
Design, Subpart D - Design of Pipeline Components, and Subpart G - General
Construction Requirements for Transmission Lines and Mains. Commenters give the
following reasons:
• These design and construction requirements should be in the non-retroactive
section of the Code.
• Subpart I requirements might be overlooked in design and construction.
Response: Subpart I contains other design requirements, such as pipe coating. PHMSA
believes consolidating corrosion control requirements strengthens the planning aspects of
the regulation. To address concerns of commenters, PHMSA is considering adding
language (such as a date) that clearly points to the non-retroactive effect of the
regulation. PHMSA is also considering adding a cross reference to subpart I in subpart D
to alert those designing pipelines of the need to look at corrosion requirements.
Recordkeeping
Many commenters expressed concern about the proposed recordkeeping requirements;
some suggested alternative approaches:
• As-built drawings and construction records provide sufficient information about
an operator’s design and construction decisions in a less burdensome way. (Gas
Piping Technology Committee)
• Variances from specific requirements should be documented. (Duke Energy,
Nicor, Gas Piping Technology Committee) Suggested language: When an
operator makes an exception to paragraphs (a), (b), or (c) of this section, the
operator must document the decisions related to the exception.
• Documenting decisions with respect to all low spots would be costly and
unnecessary (Kinder Morgan, INGAA, El Paso, Panhandle).
• If an internal corrosion control program is in place, documenting procedures
should be enough. (AGA, SoCal Gas, Southwest Gas, Paiute) Suggested
language: An operator must have written procedures to implement the provisions
of this section.
• Broad general language would be more appropriate and consistent with existing
regulations. (Texas Pipeline Association) Suggested language: An operator must
maintain records demonstrating compliance with this section for the life of the
pipeline.
Response: The proposed recordkeeping requirements are overly burdensome. We are
considering a general requirement to maintain records demonstrating compliance with the
section. As-built drawings and other construction records operators normally maintain
together with some additional explanation of variances will suffice. We have developed
a concept paper discussing this.

<<<PAGE 6>>>

Redundancy
Some commenters argued that other regulations on internal corrosion control make this
proposed rule redundant. For example, commenters pointed to the requirement that new
lines be “piggable” and hence capable of being cleaned. Others pointed to integrity
management programs (AGA) which address internal corrosion.
Response: The proposed rule is not redundant. Most rules cited by commenters are
operation and maintenance requirements, not design standards, and thus do not address
the NTSB concern. In addition, integrity management programs directly protect only
high consequence areas. The piggability requirement is a design standard, but is not
applicable to gathering lines.
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