
[Federal Register: March 24, 2010 (Volume 75, Number 56)]
[Notices]               
[Page 14243-14245]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24mr10-143]                         

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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket No. PHMSA-2010-0078]

 
Pipeline Safety: Girth Weld Quality Issues Due to Improper 
Transitioning, Misalignment, and Welding Practices of Large Diameter 
Line Pipe

AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA); 
DOT.

ACTION: Notice; issuance of advisory bulletin.

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SUMMARY: PHMSA is issuing an advisory bulletin to notify owners and 
operators of recently constructed large diameter natural gas pipeline 
and hazardous liquid pipeline systems of the potential for girth weld 
failures due to welding quality issues. Misalignment during welding of 
large diameter line pipe may cause in-service leaks and ruptures at 
pressures well below 72 percent specified minimum yield strength 
(SMYS). PHMSA has reviewed several recent projects constructed in 2008 
and 2009 with 20-inch or greater diameter, grade X70 and higher line 
pipe. Metallurgical testing results of failed girth welds in pipe wall 
thickness transitions have found pipe segments with line pipe weld 
misalignment, improper bevel and wall thickness transitions, and other 
improper welding practices that occurred during construction. A number 
of the failures were located in pipeline segments with concentrated 
external loading due to support and backfill issues. Owners and 
operators of recently constructed large diameter pipelines should 
evaluate these lines for potential girth weld failures due to 
misalignment and other issues by reviewing construction and operating 
records and conducting engineering reviews as necessary.

FOR FURTHER INFORMATION CONTACT: Alan Mayberry by phone at 202-366-5124 
or by e-mail at alan.mayberry@dot.gov.

SUPPLEMENTARY INFORMATION: 

[[Page 14244]]

I. Background

    The Federal pipeline safety regulations in 49 CFR Parts 192 and 195 
require operators of natural gas transmission, distribution, and 
hazardous liquids pipeline systems to construct their pipelines using 
pipe, fittings, and bends manufactured in accordance with 49 CFR 
Sec. Sec.  192.7, 192.53, 192.55, 192.143, 192.144, 192.149, 195.3, 
195.101, 195.112, and 195.118 and incorporated standards and listed 
design specifications. This involves reviewing the manufacturing 
procedure specification details for weld end conditions for the line 
pipe, fitting, bend, or other appurtenance from the manufacturer to 
ensure weld end conditions are acceptable for girth welding.
    During the 2008 and 2009 pipeline construction periods, several 
newly constructed large diameter, 20-inch or greater, high strength 
(API 5L X70 and X80) natural gas and hazardous liquid pipelines 
experienced field hydrostatic test failures, in-service leaks, or in-
service failures of line pipe girth welds. Post-incident metallurgical 
and mechanical tests and inspections of the line pipe, fittings, bends, 
and other appurtenances indicated pipe with weld misalignment, improper 
bevels of transitions, improper back welds, and improper support of the 
pipe and appurtenances. In some cases, pipe end conditions did not meet 
the design and construction requirements of the applicable standards 
including:
     American Petroleum Institute (API), Specification for Line 
Pipe--5L, (API 5L), 43rd (including Table 8--Tolerance for Diameter at 
Pipe Ends and Table 9--Tolerances for Wall Thickness) or 44th editions 
for the specified pipe grade;
     API 1104, 19th and 20th editions, Welding of Pipelines and 
Related Facilities;
     American Society of Mechanical Engineers (ASME) B31.8, Gas 
Transmission and Distribution Piping Systems or ASME B31.4 Pipeline 
Transportation Systems for Liquid Hydrocarbons and Other Liquids; and
     Manufacturers Standardization Society of the Valve and 
Fittings Industry, Inc. (MSS) MSS-SP-44-1996 Steel Pipeline Flanges and 
MSS MSS-SP-75-2004 Specification for High-Test, Wrought, Butt-Welding 
Fittings.
    Post-incident findings were that in some cases the pipe and 
induction bend girth weld bevels were not properly transitioned and 
aligned during welding. In some cases, the girth weld pipe ends did not 
meet API 5L pipe end diameter and diameter out-of-roundness 
specifications. Many of the problematic girth welds did not meet API 
1104 misalignment and allowable ``high-low'' criteria.
    Some girth welds that failed in-service had non-destructive testing 
(NDT) quality control problems. NDT procedures, including radiographic 
film and radiation source selection, were not properly optimized for 
weld defect detection and repairs. This was particularly the case where 
there were large variations in wall thickness at transitions. In some 
situations, NDT procedures were not completed in accordance with 
established API 1104 and operator procedures.
    Many of the integrity issues with transition girth welds were 
present on pipelines being constructed in hilly terrain and high stress 
concentration locations such as at crossings, streams, and sloping 
hillsides with unstable soils. These girth welds had high stress 
concentrations in the girth weld transitions due to the combination of 
large variations in wall thickness and improper internal bevels with 
inadequate pipe support, poor backfill practices and soil movement due 
to construction activities.

II. Advisory Bulletin ADB-10-03

    To: Owners and Operators of Hazardous Liquid and Natural Gas 
Pipeline Systems.
    Subject: Girth Weld Quality Issues Due to Improper Transitioning, 
Misalignment, and Welding Practices of Large Diameter Line Pipe.
    Advisory: Owners and operators of recently constructed large 
diameter pipelines should evaluate these lines for potential girth weld 
failures due to misalignment and other issues by reviewing construction 
and operating records and conducting engineering reviews as necessary. 
The assessments should cover all large diameter, 20-inch or greater, 
high strength line pipe transitions and cut factory bends or induction 
bends installed during 2008 and 2009, and should include material 
specifications, field construction procedures, caliper tool results, 
deformation tool results, welding procedures including back welding, 
NDT records, and any failures or leaks during hydrostatic testing or 
in-service operations to identify systemic problems with pipe girth 
weld geometry/out-of-roundness, diameter tolerance, and wall thickness 
variations that may be defective.
    The reviews should ensure that pipelines were constructed in 
compliance with the Federal pipeline safety regulations in 49 CFR Parts 
192 and 195. Operators of natural gas transmission, distribution, and 
hazardous liquids pipeline systems are required to use pipe and 
fittings manufactured in accordance with 49 CFR Sec. Sec.  192.7, 
192.53, 192.55, 192.143, 192.144, 192.149, 195.3, 195.101, 195.112, and 
195.118 and incorporated standards and listed design specifications.
    With respect to the construction process, pipe, fittings, factory 
bends, and induction bends must be made in accordance with the 
applicable standards to ensure that weld end dimension tolerances are 
met for the pipe end diameter and diameter out-of-roundness. API 1104 
specifies girth weld misalignment and allowable ``high-low'' criteria. 
API 1104--19th edition, Sec.  7.2, Alignment, specifies for pipe ends 
of the same nominal thickness that the offset should not exceed \1/8\ 
inch (3mm) and when there is greater misalignment, it shall be 
uniformly distributed around the circumference of the pipe, fitting, 
bend, and other appurtenance. ASME B31.4, Figure 434.8.6(a)-(2), 
Acceptable Butt Welded Joint Design for Unequal Wall Thickness and ASME 
B31.8, Figure I5, Acceptable Design for Unequal Wall Thickness, give 
guidance for wall thickness variations and weld bevels designs for 
transitions. API 5L, 43rd edition in Table 8--Tolerance for Diameter at 
Pipe Ends and Table 9--Tolerances for Wall Thickness, specifies 
tolerances for pipe wall thickness and pipe end conditions for diameter 
and diameter out-of-roundness. MSS-SP-44-1996 specifies weld end 
tolerances in Sec.  5.3--Hub Design, Sec.  5.4--Welding End, Figure 1--
Acceptable Designs for Unequal Wall Thickness, and Figures 2 and 3; and 
MSS-75-2004 specifies weld end tolerances in Sec.  13.3 and Figures 1, 
2, and 3 and Table 3--Tolerances.
    Pipeline owners and operators should closely review the 
manufacturing procedure specifications for the production, rolling, and 
bending of the steel pipe, fittings, bends, and other appurtenances to 
make sure that pipe end conditions (diameter and out of roundness 
tolerances) and transition bevels are suitable for girth welding. 
Pipeline owners and operators should request or specify manufacturing 
procedure specification details for weld end conditions for the line 
pipe, fitting, bend, or other appurtenance from the manufacturer to 
ensure weld end conditions are acceptable for girth welding.
    To ensure the integrity of the pipeline, field personnel that weld 
line pipe, fittings, bends, and other appurtenances must be qualified, 
follow qualified procedures, and operators must document the work 
performed. Operators should verify that field

[[Page 14245]]

practices are conforming to API 5L, API 1104, ASME B31.4 or ASME B31.8 
and operator procedures for weld bevel, pipe alignment, back welding, 
and transitions. If any bends are cut, the operator must have 
procedures to ensure that the pipe or bend cut ends are acceptable for 
welding in accordance with the listed specifications. Procedures, 
inspection, and documentation must be in place to ensure that when 
pipe, fittings, bends, and other appurtenances are welded, the field 
girth welds are made and non-destructively tested in accordance with 49 
CFR Sec. Sec.  192.241, 192.243, 192.245, 195.228, 195.230, and 
195.234. NDT procedures including film type and radiation source 
selection should be optimized for weld defect detection and repairs 
completed in accordance with established welding procedures. When there 
is a variation in wall thickness between line pipe and a segmented 
fitting, bend, or other appurtenance, consideration should be given to 
the installation of a segment of intermediate wall thickness pipe. 
Additionally, efforts should be taken to ensure pipe girth weld 
alignment is optimized by utilizing experienced and trained welders, 
suitable pipe and detailed procedures.
    Each material component of a pipeline such as line pipe, fittings, 
bends, and other appurtenances must be able to withstand operating 
pressures and other anticipated external loadings without impairment of 
its serviceability in accordance with 49 CFR Sec. Sec.  192.143 and 
195.110. In order to ensure pipeline integrity, the operator must take 
all practicable steps to protect each transmission line from abnormal 
loads while backfilling and other work continues along the right-of-way 
and to minimize loads in accordance with 49 CFR Sec. Sec.  192.317, 
192.319, 195.246(a), and 195.252. Operators should give special 
attention to girth welds with variations in wall thickness when located 
in pipeline segments where significant pipe support and backfill 
settlement issues after installation may be present, specifically in 
hilly terrain and high stress concentration locations such as at 
crossings, streams, and sloping hill sides with unstable soils.
    Even if no girth weld concerns are identified by reviewing 
construction records, if an operator has any knowledge, findings or 
operating history that leads it to believe that its newly constructed, 
high material grade, large diameter, line pipe segments contain these 
type girth weld transitions, the operator should conduct engineering 
reviews as described above with those operating pipelines to ensure 
that material, engineering design, and field construction procedures 
were in compliance with 49 CFR Parts 192 and 195. Failure to conduct 
engineering reviews and to remediate findings may compromise the safe 
operation of the pipeline.

    Authority:  49 U.S.C. chapter 601 and 49 CFR 1.53.

    Issued in Washington, DC, on March 18, 2010.
Jeffrey D. Wiese,
Associate Administrator for Pipeline Safety.
[FR Doc. 2010-6528 Filed 3-23-10; 8:45 am]
BILLING CODE 4910-60-P

