Page images
PDF
EPUB

TMENT OF TRANS

STATES OF VERTICA

Appendix

OFFICE OF THE SECRETARY OF TRANSPORTATION

WASHINGTON, D.C. 20590

Title 49-TRANSPORTATION

Chapter -Hazardous Materials Reg

DERIVATION TABLE

Proposed section

192.451.
192.481(b).

192.453, 192.455, 192.457
192.467, 192.469, 192.473.
192.481(a).

New section

192.451

ulations Board, Department

of

192.453

192.455

Transportation

192.457

[blocks in formation]

192.457.

192.465

NATURAL AND OTHER GAS BY
PIPELINE: MINIMUM FEDERAL

192.467

192.469

[blocks in formation]

192-TRANSPORTATION

[blocks in formation]

192.455.

192.475.

192.463, 192 465, 192.479.
192.459, 192.477,
192.461, 192.477.

192.491

192.487

192.487

192.489.

192 489.

192.481, 192.483, 192 485.
192.483.

Besides the numerous comments received on proposed effective dates, the question was discussed with the Technical Pipeline Safety Standards Committee. Accordingly, this regulation will become effective 30 days after the date of issue. However, certain specific provisions will not become applicable at once. The primary reason for allowing additional time for these provisions is that the corrosion regulations are new requirements that were not contained in the interim minimum Federal regulations, and it is desirable to allow appropriate leadtime to all affected parties to receive copies of the new regulation and to thoroughly review its requirements, and to make the necessary preparations and arrangements for compliance. This additional leadtime is contained in provisions relating to Subpart I differs in many respects (192.455 (a) (2)); cathodic protection of cathodic protection of new pipelines from the notice upon which it was based. existing pipelines (§ 192.457 (a) and Some changes were made for consistency (b)); interference currents ($192.473); in terminology and format. Others in- internal corrosion control ( 192.475) volve the moving of requirements from atmospheric corrosion control of existone section to another for better organi- ing aboveground pipelines ($192.479); On June 6, 1970, an amended notice nature and are based both on the com- and corrosion control records (§ 192.491) Retroactive effect on existing pipeof proposed rule making was published ments received on the notice and on the lines. Some comments related to the in the FEDERAL REGISTER (Notice 70-10 recommendations of the Technical Pipe- effect of this regulation on existing pipe35 F.R. 8833) to make certain changes of these changes is within the general dates in particular sections to make clear line Safety Standards Committee. Each lines, and suggested the insertion of iron and ductile iron pipe. After a request scope of the notice on which it was that these sections are not intended to

On April 30, 1970, the Department issued a notice of proposed rule making, Notice 70-8, containing requirements for corrosion control (35 F.R. 2127, May 6, 1970). Interested persons were invited to participate in the making of the proposed rules by submitting written comments

before June 29, 1970.

in the proposed rules relating to cast

for a public hearing on the requirements of these two notices, a public hearing

192.487

192.489.
192.491.

192.485 (a) and (b).
192.485 (c).
192.493.

zation. Other changes are substantive in

based.

apply to installations, repairs or replaceA number of recommendations in- ments made before the effective date. (see Notice 70-12, 35 F.R. 10596, June 30, cluded in the comments were beyond the 1970) was held on July 20, 1970, and scope of the proposed regulations, and comment was received on the proposed could therefore not be included in the applicability of the requirements to ex- final rule. However, these recommendaisting pipelines and to cast iron or ductile tions will be considered for inclusion in iron pipe. The information and views future rule-making actions. presented in the comments and at the Some of the comments were directed hearing have been fully considered, and to the overall effect of Subpart I, and are reflected in this final rule. Some sec- these general subjects are discussed tions contained in the notice have been below. All other significant changes and consolidated, eliminated, or reorganized comments are discussed in a section-byand most sections have been renumbered. section analysis. The deviation table below indicates the corresponding section number in the notice for each section of the final rule.

(See § 192.455 (e) (installation of aluminum); $192.461 (protective coating); 192.467 (electrical isolation); and $192.483 (repaired or replaced pipe).) As stated in the preamble when Part 192 was issued, there is no basis for such concern. The Natural Gas Pipeline Safety Act (section 3(b)) makes clear that only standards applying to the extension, operation, replacement, or maintenance, and subsequent inspection and subsefacilities in existence on the date the quent testing are applicable to pipeline standards are adopted.

Effective date. Section 3(c) of the Natural Gas Pipeline Safety Act requires that standards and amendments thereto prescribed under the Act "shall become However, provisions applicable to exeffective 30 days after the date of isting lines need not be limited to cases issuance unless the Secretary, for in which a facility is hazardous to life good cause recited, determines an earlier or later effective date is required as a result of the period reasonably necessary for compliance". The notice invited comment on the adequacy of specific proposed effective dates, both as to whether earlier dates would be in the interest of increased safety and whether later dates are indicated by factors of cost or feasibility.

FEDERAL REGISTER, VOL. 36, NO. 126-WEDNESDAY, JUNE 30, 1971

or property, as asserted in some comments, but are permissible as part of the regular operation and maintenance requirements for existing lines. The determination of areas of active corrosion on existing pipelines by electrical survey, by study of corrosion and leak history records and by leak detection survey, as well as the application of cathodic protection to such areas, or repaired or replaced areas, and subsequent inspection and testing to determine the adequacy and efficacy of corrosion control, are examples of operation, replacement, maintenance, and subsequent testing and inspection specifically permitted under the Act.

Where a particular section applies only to existing pipelines, that is made clear by use of the phrase "pipelines installed before August 1, 1971". (See $192.457, 192.479 (b).)

Distinction between high and low stress pipe; distinction between bare and coated pipe. To be consistent with the previously issued subparts of Part 192, the terms "transmission line" and "distribution line" have been substituted for the phrases "pipelines, mains and service lines operating at 20 percent or more of SMYS", and "pipelines, mains, or service lines operating at less than 20 percent of SMYS", which were used in the notice. Some of the comments maintained that the distinction between high- and low-stress pipe, and between bare and coated pipe, was unjustifiable as a basis for differing corrosion control require ments. However, the problems of cathodically protecting existing distribution lines are different from those of existing transmission lines. Special problems make compliance in the case of the distribution lines more difficult, so more time must be allowed for meeting these requirements. In many cases it is more practical to cathodically protect an existing coated transmission line in its entirety than to survey it for "hot spots" and cathodically protect only those areas where active corrosion is found. Consequently, it is required that effectively coated existing transmission lines be cathodically protected within 3 years of the effective date, but 5 years is allowed for existing bare transmission lines, all distribution lines and all station piping.

Distinction based on type of metal. Special provisions deal with specific metals having unique characteristics, such as copper (§ 192.455 (c) (1)), aluminum (§ 192.455 (e)), and cast iron and ductile iron (§ 192.489). However, the phrase "steel or aluminum pipeline", as used in the notice, has been eliminated, since there was no intention to exclude other types of metallic pipe such as wrought iron.

Section 192.451. This section, stating the scope of the subpart, has been rewritten. The word "pipeline" has now been substituted for the words "gas pipeline facilities" and "pipelines, mains, service lines, and related facilities" which were used in proposed § 192.451, as well as in many other sections of the notice. As defined in § 192.3, "pipeline" means all

parts of those physical facilities through which gas moves in transportation, including pipes, valves, and other appurtenances attached to pipe, compressor units, metering stations, regulator stations, delivery stations, holders, and fabricated assemblies. The second sentence of the proposed scope section in the notice was deleted as unnecessary.

Various suggestions were made that the scope section state that these requirements are for the protection of pipelines from "harmful" corrosion, or corrosion "detrimental to safety", or that it state that it prescribes minimum requirements for the protection of pipelines from corrosion, "consistent with public safety", in order to make clear that not every degree or type of existing corrosion imposes an obligation on the operator to take protective steps. These proposals were deemed unnecessary, since their purpose is accomplished by the definition of "active corrosion" in 192.457 (c) as "continuing corrosion which, unless controlled, could result in a condition that is detrimental to public safety". Moreover, under §§ 192.485, 192.487, and 192.489, remedial action is required only where corrosion is of the degree or extent described in those sections. In addition, cathodic protection of most existing lines is now required only in "areas in which active corrosion is found" (§§ 192.457(b) and 192.465 (e)) thus eliminating any implication that an operator must cathodically protect the pipeline in all areas of existing corrosion, even where the operator has not been able to detect it.

Section 192.453. This section, based on proposed 192.481(b), which applied only to cathodic protection systems, now applies to all procedures to implement the requirements of this subpart, "including those for the design, installation, operation, and maintenance of cathodic protection systems".

Recommendations that some standards be included to assure the competence of the "person qualified by experience and training in pipeline corrosion control methods", or that such a person be qualified under the terms of the accreditation program of the National Association of Corrosion Engineers, were deemed inappropriate at this time. The word "corrosion specialist", suggested as a substitute for the word "person", was thought to be redundant in view of the additional language, "qualified by experience and training in pipeline corrosion control methods". A person so qualified, but not officially designated as a corrosion specialist, should not be precluded from acting under this section.

Section 192.445. Paragraph (a) of 192.455 requires, with certain exceptions, protection against external corrosion for all newly constructed pipelines, by means of a combination of external protective coating and cathodic protec

tion.

The proposed regulation would have required new buried pipelines to be "cathodically protected not later than 1 year after completion of construction".

Since time must be allowed for the environment to reach a stable level due to changes in soil settling and in oxygen and water content of backfill, before final measurements can be taken to determine adequacy of protection, it is now provided that a properly designed cathodic protection system must be "installed and placed in operation within 1 year". An additional year will then be available under 192.465 for any adjustments necessary because of changes in the soil following construction.

No differentiation has been made in 192.455 (a) between new transmission and new distribution lines. Except as provided in paragraphs (b) and (c), all new pipelines must be coated and cathodically protected.

New pipe that replaces pipe removed from an existing buried or submerged pipeline because of external corrosion, is covered by 192.483 (a) and (b), but it should be noted that such new replacement pipe also must be coated and cathodically protected.

Paragraph (b) provides an exception to the requirements of paragraph (a). Many comments recommended that an exception to the coating and cathodic protection requirements, similar to that proposed for new copper pipelines (where the operator can demonstrate by test, investigation or experience in the area of application that a corrosive situation does not exist), should be extended to all new pipelines. This has been done in paragraph (b) of 192.455, but with additional safeguards. Certain minimum tests for soil resistivity and corrosion accelerating bacteria will be required. These tests are a prerequisite in every instance of an installation made without complying with the requirements of paragraph (a). In addition. within 6 months after such an installation, the operator must conduct tests, including pipe-to-soil potential measurements and soil resistivity measurements at potential profile peak locations, and the pipeline must be cathodically protected in those areas in which the tests indicate a corrosive condition exists.

exception to the requirements for coatParagraph (c) provides an additional ing and cathodic protection, for new temporary pipelines, where the operating period of service is not to exceed 5 years beyond installation.

Paragraph (d) provides that even where protection of a new buried pipeline against external corrosion control is not required under one of these exceptions set out in paragraphs (b) or (c). if the pipeline is coated, it must then also be cathodically protected. This is necessary because first leaks can develop sooner on a coated pipeline than they harmful discharge of current would be would on the same line left bare, since concentrated at the breaks in the coating (holidays).

Paragraph (e) of 192.455 has been modified to incorporate suggested language in regard to installation of aluminum, which is the same as that used in

the 1969 edition of NACE Standard RP01-69. Comments criticized the term "highly alkaline environment" used in the notice as too vague, and suggested that the use of aluminum should be prohibited in "an environment with a natural pH in excess of 8.0", unless tests indicate its suitability in the particular environment involved.

Finally, it should be noted that no exception to the requirements of 192.455 is provided for new cast iron or ductile iron. Because of the unique physical characteristics of its corrosion process (graphitization), and because of the normal allowance of extra wall thickness, it was argued in some of the comments and at the hearing on July 20, 1970, that it should not be required that newly installed cast iron or ductile iron be coated and cathodically protected, but that a loose polyethylene wrap should be considered an appropriate coating adequate for proper corrosion control. But moisture and ground water which can enter the loose polyethylene wrap may form a breeding ground for bacteriological corrosion. Moreover, in the event there is a break in the polyethylene wrap and corrosion started, there is no way to apply cathodic protection to prevent further corrosion. The current would be intercepted by the insulating qualities of the polyethylene sheet, and cathodic protection would only reach the metal under the break. The other areas under the wrap that may be corroding from water and access to oxygen would not be cathodically protected. Therefore, new cast iron and ductile iron have not been treated differently from steel and a coating bonded to the pipe and cathodic protection are required.

Section 192.457. Whereas § 192.455. which deals with new pipelines, makes no distinction for corrosion control purposes, between new transmission lines and new distribution lines, generally requiring both to be coated and cathodically protected in the entirety, § 192.457, which applies to existing pipelines, has different requirements for coated transmission lines than for distribution lines.

Several comments pointed out that coated pipe with deteriorated coating that is no longer effective should be treated as bare pipe for corrosion control purposes. Accordingly, the proposed requirement that coated pipelines operating at 20 percent or more of SMYS must be cathodically protected in the entirety within 3 years, now applies only to existing buried or submerged transmission lines that have an effective external coating (192.457(a)). The effectiveness of the coating is to be established by tests to determine the current requirements of the pipeline for cathodic protection. Coating is deemed ineffective if the cathodic protection current requirements are substantially the same as if the pipeline were bare.

Paragraph (b) of 192.457 provides that except for cast iron or ductil bare transmition lines (including those with ineffective coating), bare or coated station piping, and bare or coated distribu

tion lines, all must be cathodically pro-
tected within 5 years in areas in which
active corrosion is found. "Active cor-
rosion" is defined in paragraph (c).

The proposed regulation would have
required cathodic protection of existing
distribution lines and bare transmission
lines within 5 years, "in areas in which
corrosion exists". The operator was to
determine these areas by electrical sur-
vey or other means. There appeared to be
some concern in the comments that the
proposal contained an absolute require-
ment that every area of existing corro-
sion be found and protected against
within 5 years. This was apparently felt
to be impossible for some distribution
lines, since determination of areas of cor-
rosion by electrical survey is often im-
practical in the case of distribution lines
(such as those under paved city streets
and sidewalks). This has now been
changed to require cathodic protection
"in areas in which active corrosion is
found", and that areas of active corro-
sion be determined by electrical survey.
or "where electrical survey is impracti-
cal, by the study of corrosion and leak
history records, by leak detection survey,
or by other means". This modified lan-
guage should make clear that the oper-
ator is not obligated to take action con-
cerning active corrosion which cannot be
found by the required methods. The op-
erator must conduct electrical surveys in
areas where they are practical. In other
areas, he must make diligent efforts, uti-
lizing leak surveys, all available records
such as corrosion and leak history rec-
ords, or other appropriate methods, to
discover active corrosion. Leak surveys

could be made by such commonly used

means of leak detection as flame loniza-
tion, infrared detectors and combustible
gas detectors. If these efforts do not in-
dicate the presence of active corrosion,
the operator may assume that none ex-
ists, until such time as an actual indica-
tion of its existence arises. Moreover, it
should be noted that an operator may ap-
ply for a waiver if it is shown that justi-
fication exists for not meeting the 5-year
time period in cathodically protecting
"hot spots" found by the methods set
out in 192.457(b).

In summary, 192.457 now provides
that existing, effectively coated transmis-
sion lines must be cathodically protected
in the entirety within 3 years, while all
other existing lines (including bare trans-
mission lines, bare or coated buried sta-
tion piping operating at above or below
20 percent of SMYS, and bare or coated
distribution lines) must be cathodically
protected within 5 years in areas in which
active corrosion is found. On new con-
struction, § 197.455 provides that all new
Pipe (both transmission and distribu-

tion) must be coated and cathodically
protected within 1 year of installation
unless the operator can demonstrate that
a corrosive environment does not exist.

Section 192.459. The requirement that
whenever any buried piping is exposed
for any reason it must be examined for
evidence of external corrosion has been
modified. Comments suggested that it be
made clear that this requirement would

not necessitate tearing off good coating to examine the pipe. As the section is rewritten, it requires only that "Whenever an operator has knowledge" that any portion of buried pipeline is exposed, the pipe must be examined for evidence of external corrosion "if the pipe is bare or if the coating is deteriorated".

Section 192.461. This section, dealing with protective coating, has been slightly reworded.

Subparagraph (a) (2) requires a protective external coating to have sumcient adhesion to the metal surface to "effectively resist" (rather than "prevent") underfilm migration of moisture, in response to comments asserting that the coating could not absolutely prevent underfilm migration of water.

Paragraph (c) relating to inspection of coating prior to lowering the pipe and backfilling, now requires repair only of "any damage detrimental to effective corrosion control", since the comments indicated that minor damage often does not require repair.

Paragraph (e) is a new paragraph requiring that precautions be taken to minimize damage to coating during installation by boring or driving. This paragraph, although proposed in Notice 70-3, Subpart H (Customer's Meters, Service Regulators, and Service Lines) as proposed 192.429(b), was omitted in the final rule for that subpart, since it was considered to be more properly a part of the corrosion subpart.

Section 192.463. Paragraph (a) of this section refers to the criteria for cathodic protection contained in a new Appendix D. rather than to paragraph 6.3 of the 1969 edition of NACE Standard RP-0169. However, it should be noted that the criteria in the appendix are substantially the same as those in the NACE Standard. In addition, it is now provided that "If none of these criteria is applicable, the cathodic protection system must provide a level of cathodic protection at least equal to that provided by compliance with one or more of these criteria." It was felt that the possibility of an exception should be provided, but that where the criteria are applicable, they should be followed.

In accordance with several suggested comments, paragraph (d) of proposed section 192.457 was deleted as unnecessary, and paragraph (f) of that proposed section has been reworded to eliminate the requirement that the cathodic protection "assure proper performance of the protective coating system", and instead now requires that the amount of cathodic protection must be controlled "so as not to damage the protective coating or the pipe".

Section 192.465. The section on monitoring differs from the proposal in several ways. It applies to monitoring of both new and existing lines. In paragraph (a), offshore pipelines, where monitoring is impractical, have been excepted. The phrase "at intervals not exceeding 12 months" has been changed to "at least once each calendar year, with intervals not exceeding 15 months". The

purpose of the change was to allow seasonal considerations in scheduling annual inspections, and it was felt that 3 months' leeway would provide sumcient flexibility for this purpose.

Instead of requiring that each interference bond be electrically checked for proper performance at intervals not exceeding 2 months, it is now provided in 192.465(c) that each interference bond "whose failure would jeopardize structure protection", must be electrically checked for proper performance at intervals not exceeding 2 months. Each other interference bond must be checked at least annually, but with intervals not exceeding 15 months.

Section 192.467. This section, entitled "External corrosion control: Electrical isolation", is based on the proposed sections which dealt with electrical insula

tion on new construction and existing pipelines, and with clearance between pipe and underground structures on new construction.

Paragraph (a) still requires that each buried pipeline must be electrically isolated from other underground metallic structures, but in accordance with suggestions received, it permits an exception if the pipeline and the other structures are electrically interconnected and cathodically protected as a single unit.

Paragraph (b) of 192.467, requires that an insulating device be installed where electrical isolation of a portion of a pipeline is necessary to facilitate corrosion control. It was felt that this performance-type language is suficient to cover such specific situations as the necessary insulation of ferrous valves and fittings installed in underground copper service lines.

Paragraph (c) of § 192.467, providing for electrical isolation of the pipeline from metallic casings that are a part of the underground system, now permits other measures to minimize corrosion of the pipeline inside the casing, where isolation is impractical. The additional language was added in response to comments suggesting that this requirement should not apply to a service going through a casing in a cement or masonry wall, where the casing is above ground. Other measures that may be taken include placing a noncorrosive casing filler made of high dielectric material in the annular space between the pipe and casing.

Paragraph (f) concerning protection against damage due to fault currents and lightning now refers to "areas where fault currents or unusual risk of lightning may be anticipated".

Proposed 192.463 (e) has been eliminated as unnecessary, since the specific situations described in that paragraph are covered by the more performanceoriented type of language of 192.467 (a) and (b).

Section 192.473. This section now requires that after July 31, 1973, each operator whose pipeline system is subjected to stray currents must have a continuing program to minimize the detrimental effects of such currents,

Comments indicated that the 12-month leadtime originally proposed was insufficient for the acquisition of manpower and equipment for such a program.

Sections 192.475 and 192.477. These sections are essentially the same as proposed. However, paragraph (c) of 192.475, providing that gas containing more than 0.1 grain of hydrogen sulfide stored in pipe-type or bottle-type holdper 100 standard cubic feet may not be ers, is newly added. It was originally D (Design of Piping System Components proposed as part of Notice 70-7, Subpart and Facilities), as proposed § 192.168(b), but was not included in Subpart D, since it was considered to be more appropriately within the corrosion subpart.

In response to comments, § 192.477 makes clear that coupons are required ported". However, it should be noted that only "if corrosive gas is being trans192.475 (b) applies also in cases where corrosive gas is not being transported, but internal corrosion is caused by other factors.

Sections 192.479 and 192.481. The sections on atmospheric corrosion control have been completely rewritten. The proposal would have required all new and existing steel, cast iron and ductile iron aboveground pipelines to be coated or jacketed within 1 year for the prevention of atmospheric corrosion. This requirement would have applied to aluminum and copper pipe only when exposed to an atmospheric environment corrosive to those metals.

The comments objected to the 1 year time limitation as insufficient, and also suggested that coating only be required where atmospheric corrosion was actually taking place. While 192.479(a), applying to newly installed aboveground pipelines, still requires that such pipelines be cleaned and coated with a material suitable for the prevention of atmospheric corrosion, it now also allows for an exception to this requirement if the operator can demonstrate by tests, investigation or experience in the area of application that a corrosive atmosphere does not exist.

Paragraph (b), applying to existing aboveground pipelines, now requires that they be cleaned and coated within 3 years, but only in areas where atmospheric corrosion has taken place on the pipeline.

Section 192.481 requires that at intervals not exceeding 3 years, aboveground pipelines must be reevaluated and necessary action taken to maintain protection against atmospheric corrosion.

replacement is necessitated by external corrosion, since it would normally be impossible to make such a demonstration. However, it should be noted that if copper pipe is used to replace corroded steel, cast iron or ductile iron, the provisions of 192.455 (c) (2) might permit the use of uncoated copper replacement without cathodic protection, in the highly unlikely event that the operator could demonstrate by test that the environment (which had been corrosive to copper. the other metals) was not corrosive to

Except for repaired cast iron or ductile iron, a segment of buried pipe that is repaired because of external corrosion must be cathodically protected. Repaired cast iron and ductile iron are excepted from the cathodic protection requireprotection current, as normally provided ment because the density of cathodic by galvanic anodes, is not sumcient to reach the cast iron beneath the graphitized surface so as to prevent further graphitization. Current of such low density from such low electromotive force collects on the graphitized area and continues through adjacent cast iron and back to the galvanic anode source without providing protection.

It should be noted that at this time, the regulations are not requiring that repaired pipe be coated in every case, since it is not always practical to do so, espe cially where the repair is in a very small area, or on a bare pipeline. However, where the repaired segment is part of an effectively coated pipeline, the repaired area would also have to be coated.

The proposed regulation provided that generally corroded pipe would not need to be replaced or repaired if the operating pressure were reduced so as to be commensurate with the specified limits on operating pressure based on the actual remaining wall thickness. That option is retained in § 192.485 (a) covering general corrosion on transmission lines. However, $192.487(a) dealing with general corrosion on distribution lines does not provide the option of reducing operating pressure instead of replacing the pipe. low pressure, the reduction of pressure Since such lines are already operating at would be meaningless. In this connection, it should be noted that the minimum percentage of remaining wall thickness required in such cases is not contingent external loads. on internal pressure (hoop stress) but on

Sections 192.485 and 192.487. The proposed regulations dealing with remedial measures for isolated corrosion pitting were the subject of considerable comment. Based on the information available veloped the following regulations which at this time, the Department has deare considered adequate to protect the public:

Section 192.483. This section on general remedial measures requires that all new replacement pipe installed because of external corrosion (including cast iron or ductile iron) must be coated and cathodically protected, as is required for new pipelines in § 192.455 (a). The ex-192.485 Remedial measures: transmission ception to these requirements allowed for new pipelines in § 192.455 (b) (where the operator can demonstrate that a corro

sive environment does not exist), would not apply to replacement pipe, where

lines....

(b) Localized corrosion pitting. Each segment of transmission line pipe with localized paired, or the operating pressure must be recorrosion pitting must be replaced or reduced based on the actual remaining wall

thickness in the pits, if either of the following exists:

(1) The diameter of the pits as measured at the surface of the pipe is greater than three times the nominal wall thickness of the pipe.

(2) The remaining wall thickness at the bottom of the pits is less than 30 percent of the nominal wall thickness.

192.487 Remedial measures: distribution lines other than cast iron or ductile iron lines....

(b) Localized corrosion pitting. Except for cast iron or ductile iron pipe, each segment of distribution line pipe with localized corrosion pitting must be replaced or repaired if either of the following exists:

(1) The diameter of the pits, as measured at the surface of the pipe, is greater than five times the nominal wall thickness of the pipe.

(2) The remaining wall thickness at the bottom of the pits is less than 20 percent of the nominal wall thickness.

However, we are aware that the completion of research now going on is anticipated in the near future, on the subject of the effect of pitting on the integrity of pipe, requiring repair or replacement for the protection of the public. Accordingly, the Department intends to delay the issuance of these regulations on localized corrosion pitting, in order to hold a public hearing on July 20, 1971, to explore the problem further. (See p. 12309 of this issue.) This will give interested persons an opportunity to present new material or to demonstrate that the criteria set out above are inappropriate.

In issuing this rule, the Department has included general criteria on corrosion pitting in 192.485 (b) and 192.487(b) as interim regulations. These interim regulations give the operator discretion to determine the severity of pitting that requires remedial action.

Unless the hearing discloses information indicating other criteria are more appropriate, the regulations set forth above in this preamble will be substituted for the interim provisions within 60 to 90 days from the effective date of this regulation.

Section 192.491. The comments on this provision urged that construction drawings and records should not both be required, and that records or drawings should not be required as to all neighboring structures. In response to these comments, § 192.491(a) now requires that "records or maps" be maintained to show the location of cathodically protected piping, cathodic protection facilities "other than unrecorded galvanic anodes installed prior to August 1, 1971", and neighboring structures that are "bonded to" the cathodic protection system.

In response to other comments urging that the retention of all records of tests, surveys, and inspections is unnecessary and unduly burdensome, paragraph (b) now provides for retention only of records, tests, and inspections in sufficient

detail to demonstrate the adequacy of corrosion control measures, or, in the case of unprotected pipelines, that a corrosive condition does not exist.

Appendix D. An appendix has been added, setting out criteria for cathodic protection required by § 192.463(a), and methods of determining such measurements as voltage, voltage shifts, and polarization voltage shifts. These criteria and methods of measurement are based on the 1969 issue of the National Association of Corrosion Engineers' Standard RP-01-69, Recommended Practice-Control of External Corrosion on Underground or Submerged Metallic Piping Systems.

Report of Technical Pipeline Safety Standards Committee. Section 4 of the Natural Gas Pipeline Safety Act requires that all proposed standards and amendments to such standards be submitted to the Committee and that the Committee be afforded a reasonable opportunity to prepare a report on the "technical feasibility, reasonableness, and practicality of each such proposal". This amendment to Part 192 has been submitted to the Technical Committee and that Committee has submitted a favorable report. The Committee's report and the minority views of the Committee member who disagreed with the majority report are set forth below.

JUNE 21, 1971. Memorandum to: The Secretary of Transportation, Attention: Joseph C. Caldwell,

Acting Director Office of Pipeline Safety. From: Secretary. Technical Pipeline Safety

Standards Committee.

Subject: Office of Pipeline Safety Proposed Requirements For Corrosion Control (Part 192, Subpart I).

The following letter and attachments represent an official report by the Technical Pipeline Safety Standards Committee concerning the Committee action related to "Requirements for Corrosion Control (Part 192, Subpart I)" which the Office of Pipeline Safety proposes to adopt as a part of Minimum Federal Safety Standards: Transportation of Natural and Other Gas by Pipeline.

The Committee reviewed proposals of the Once of Pipeline Safety at a meeting held on April 13-14, 1971, and through an informal ballot procedure recommended modification to the OPS proposed regulations. The Office of Pipeline Safety considered the recommendations of the Technical Committee and prepared a revised draft regulation which reflected recommendations of the Committee. The revised draft regulation accompanied by a "Discussion of Technical Committee Recommendations" prepared by OP8 was distributed to the membership of the Committee on May 4, 1971, by the undersigned together with a formal letter-ballot.

The results of the letter-ballot as finally tabulated reveal that 13 members of the Committee approved the proposed regulation as being technically feasible, reasonable and practicable. One member disapproved the proposed regulation.

Attached, as Item A, are the minority views expressed by the dissenting Committee member.

Also attached, as Item B. is a summary of views expressed by Committee members who voted in favor of the proposed regulation but disagreed with minor specifics.

LOUIS W. MENDONSA,

EXPLANATION OF THE DISAPPROVAL BY FREDERIC A. LANG OF THE PROPOSED MAJORITY REPORT ON THE PROPOSED PART 192 SUBPART 1 "REQUIREMENTS FOR CORROSION CONTROL." As a member of the Technical Pipeline Safety Standards Committee, I disapprove of the proposed majority report because it is less than adequate for providing safety to the public living beside gas pipelines, distribution lines, and mains.

Design and operation of pipelines as regulated by Federal Pipeline Safety Standards Part 192 already issued except for this Subpart I, does not contemplate any weakening of the pipe wall by corrosion, therefore, the "Requirements of Corrosion Control" as proposed, should guarantee, within practical

limits, that corrosion does not occur. Unfor

tunately, the regulations as drafted are less

than adequate to prevent a dangerous degree of corrosion.

My comments on the need for better corrosion control appear in the transcript of the Committee meetings held April 13 and 14, 1971, to discuss the proposed regulation. In summary, my recommendations are that cathodic protection be used on all piping at all times to prevent corrosion and that scientifically designed sampling be used to determine whether corrosion has occurred. When corrosion has occurred the piping should be replaced or downrated in accordance with the remaining wall thickness available to contain the pressurized gas.

FREDERIC A. LANG.

This regulation is issued under the authority of the Natural Gas Pipeline Safety Act of 1968 (49 U.S.C. § 1671 et. seq.), Part 1 of the Regulations of the Office of the Secretary of Transportation (49 CFR Part 1), and the delegation of authority to the Director, Office of Pipeline Safety, dated November 6, 1968 (33 F.R. 16468).

In consideration of the foregoing, a new Subpart I is added to Part 192 of Title 49 of the Code of Federal Regulations, effective August 1, 1971, to read as set forth below.

Issued in Washington, D.C., on June 25, 1971. JOSEPH C. CALDWELL,

Acting Director, Ofice of Pipeline Safety.

Subpart I—Requirements for Corrosion Control

[blocks in formation]

71-018 O- 72 - 11

« PreviousContinue »