GTG incident on 2011-06-14 — TX

Operator
Tennessee Gas Pipeline Co (El Paso)
Cause
Material Failure Of Pipe Or Weld
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities 0 injuries
Property damage (nominal)
$306,000
Incident datetime
2011-06-14 10:10
Report number
Location
TX
Narrative
Tennessee gas pipeline (tgp) was notified on june 14, 2011, by boemre and by a producer, stone energy, of bubbles on the ocs in bay mar block 5, the coordinates of which indicated they were coming from tgp's pipeline facility. Upon investigation, divers removed protective mats from a subsea tie-in assembly on tgp's 524c-400 pipeline and found a crack in the neck of a 2" flange that was part of the tie-in of an intersecting pipeline. Repairs were made and the pipeline facility was placed back into service. Metallurgical analysis concluded that the crack in the weld of the 2" flange was likely due to overload fracture due to external bending and/or tensile forces. Such forces were possibly caused by instability of the subsea floor and concrete mats placed over assembly at time of construction. Year of pipe manufacture is assumed to be commensurate with year of installation.
Detailed record list
Report Received Date
2011-07-06 00:00:00
Iyear
2011
Report Number
20110228
Supplemental Number
16139
Report Type
Supplemental Final
Operator Id
Name
Tennessee Gas Pipeline Co (El Paso)
Operator Street Address
1001 Louisiana St
Operator City Name
Houston
Operator State Abbreviation
TX
Operator Postal Code
77002
Local Datetime
2011-06-14 08:45:00
Location Latitude
Location Longitude
Nrc Rpt Num
Nrc Rpt Datetime
2011-06-14 11:15:00
Commodity Released Type
Natural Gas
Unintentional Release
675
Intentional Release
1970
Accompanying Liquid
0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Shutdown Due Accident Ind
Yes
Shutdown Datetime
2011-06-14 14:20:00
Restart Datetime
2011-06-28 19:30:00
Ignite Ind
No
Explode Ind
No
Num Pub Evacuated
0
Incident Identified Datetime
2011-06-14 10:10:00
On Site Datetime
2011-06-15 18:30:00
On Off Shore
Offshore
Off Water Depth
40
Off Accident Origin
On The Outer Continental Shelf (Ocs)
Off Ocs Area
Bay Mar
Off Ocs Block
5
Off Area Accident Type
Below Water, Pipe On Or Above Seabed
Pipe Facility Type
Interstate
System Part Involved
Offshore Pipeline, Including Riser And Riser Bend
Item Involved
Weld/fusion, Including Heat-Affected Zone
Pipe Diameter
16
Pipe Wall Thickness
0.406
Pipe Smys
42000
Pipe Specification
Api 5lx
Pipe Seam Type
Seamless
Pipe Manufacturer
National Tube
Pipe Coating Type
Coal Tar
Weld Subtype
Pipe Girth Weld
Installation Year
1961
Manufactured Year
1961
Material Involved
Carbon Steel
Release Type
Leak
Leak Type
Crack
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
361
Heat Damage Ind
No
Non Heat Damage Ind
No
Hca Fatalities Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
2700
Est Cost Intentional Release
7884
Est Cost Prop Damage
306000
Est Cost Emergency
4000
Est Cost Other
0
Prpty
320584
Accident Psig
700
Mop Psig
1069
Mop Cfr Section
Not On Omb-Approved Form When Submitted
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Upstream Valve Type Ind
Manual
Downstream Valve Type Ind
Manual
Length Segment Isolated
81840
Internal Inspection Ind
No
Diameter Change Ind
Yes
Tight Mitered Ind
Yes
Other Inspection Ind
Yes
Internal Inspection Details
At Subsea Tie-In Where A Different Diameter Line Intersects At 90 Degrees.
Operation Complications Ind
No
Pipeline Function
Transmission System
Scada In Place Ind
Yes
Scada Operating Ind
Yes
Scada Functional Ind
Yes
Scada Detection Ind
No
Scada Conf Ind
No
Accident Identifier
Other
Accident Details
Tgp Was Notified By Both Boemre And By Stone Energy, A Producer.
Investigation Status
No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate)
Investigation Status Details
Pressures were not outside normal operating limits.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Material Failure Of Pipe Or Weld
Cause Details
Environmental Cracking-Related
Pwjf Failure Type
Environmental Cracking-Related
Field Exam Ind
Yes
Metallurgical Ind
Yes
Stress Subtype
Other
Stress Details
Overload Fracture Induced By External Bending And/or Tensile Forces.
Additional Crack Ind
Yes
Collected Data Ind
No
Has Hydrtst Conduc Before Ind
No
Direct Asmnt Conducted
No
Non Destructive Exam Ind
No
Preparer Name
Z****** R*****
Preparer Title
Engineer - Pipline
Preparer Email
Z*************@k***********.com
Preparer Telephone
7134206633
Authorizer Name
Z****** R*****
Authorizer Title
Engineer - Pipline
Authorizer Telephone
7134206633
Authorizer Email
Z*************@k***********.com
Narrative
Tennessee gas pipeline (tgp) was notified on june 14, 2011, by boemre and by a producer, stone energy, of bubbles on the ocs in bay mar block 5, the coordinates of which indicated they were coming from tgp's pipeline facility. Upon investigation, divers removed protective mats from a subsea tie-in assembly on tgp's 524c-400 pipeline and found a crack in the neck of a 2" flange that was part of the tie-in of an intersecting pipeline. Repairs were made and the pipeline facility was placed back into service. Metallurgical analysis concluded that the crack in the weld of the 2" flange was likely due to overload fracture due to external bending and/or tensile forces. Such forces were possibly caused by instability of the subsea floor and concrete mats placed over assembly at time of construction. Year of pipe manufacture is assumed to be commensurate with year of installation.
Report Received Date 2011-07-06 00:00:00
Iyear 2011
Report Number 20110228
Supplemental Number 16139
Report Type Supplemental Final
Operator Id 19160 PHMSA Enforcement
Name Tennessee Gas Pipeline Co (El Paso)
Operator Street Address 1001 Louisiana St
Operator City Name Houston
Operator State Abbreviation TX
Operator Postal Code 77002
Local Datetime 2011-06-14 08:45:00
Location Latitude 29.047166 Google Maps OpenStreetMap
Location Longitude -90.229333 Google Maps OpenStreetMap
Nrc Rpt Num 979623 NRC Report How to search
Nrc Rpt Datetime 2011-06-14 11:15:00
Commodity Released Type Natural Gas
Unintentional Release 675
Intentional Release 1970
Accompanying Liquid 0
Fatality Ind No
Fatal 0
Injury Ind No
Injure 0
Shutdown Due Accident Ind Yes
Shutdown Datetime 2011-06-14 14:20:00
Restart Datetime 2011-06-28 19:30:00
Ignite Ind No
Explode Ind No
Num Pub Evacuated 0
Incident Identified Datetime 2011-06-14 10:10:00
On Site Datetime 2011-06-15 18:30:00
On Off Shore Offshore
Off Water Depth 40
Off Accident Origin On The Outer Continental Shelf (Ocs)
Off Ocs Area Bay Mar
Off Ocs Block 5
Off Area Accident Type Below Water, Pipe On Or Above Seabed
Pipe Facility Type Interstate
System Part Involved Offshore Pipeline, Including Riser And Riser Bend
Item Involved Weld/fusion, Including Heat-Affected Zone
Pipe Diameter 16
Pipe Wall Thickness 0.406
Pipe Smys 42000
Pipe Specification Api 5lx
Pipe Seam Type Seamless
Pipe Manufacturer National Tube
Pipe Coating Type Coal Tar
Weld Subtype Pipe Girth Weld
Installation Year 1961
Manufactured Year 1961
Material Involved Carbon Steel
Release Type Leak
Leak Type Crack
Class Location Type Class 1 Location
Could Be Hca No
Pir Radius 361
Heat Damage Ind No
Non Heat Damage Ind No
Hca Fatalities Ind No
Est Cost Oper Paid 0
Est Cost Unintentional Release 2700
Est Cost Intentional Release 7884
Est Cost Prop Damage 306000
Est Cost Emergency 4000
Est Cost Other 0
Prpty 320584
Accident Psig 700
Mop Psig 1069
Mop Cfr Section Not On Omb-Approved Form When Submitted View CFR 49 §192
Accident Pressure Pressure Did Not Exceed Maop
Pressure Restriction Ind No
Upstream Valve Type Ind Manual
Downstream Valve Type Ind Manual
Length Segment Isolated 81840
Internal Inspection Ind No
Diameter Change Ind Yes
Tight Mitered Ind Yes
Other Inspection Ind Yes
Internal Inspection Details At Subsea Tie-In Where A Different Diameter Line Intersects At 90 Degrees.
Operation Complications Ind No
Pipeline Function Transmission System
Scada In Place Ind Yes
Scada Operating Ind Yes
Scada Functional Ind Yes
Scada Detection Ind No
Scada Conf Ind No
Accident Identifier Other
Accident Details Tgp Was Notified By Both Boemre And By Stone Energy, A Producer.
Investigation Status No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate)
Investigation Status Details Pressures were not outside normal operating limits.
Employee Drug Test Ind No
Contractor Drug Test Ind No
Cause Material Failure Of Pipe Or Weld
Cause Details Environmental Cracking-Related
Pwjf Failure Type Environmental Cracking-Related
Field Exam Ind Yes
Metallurgical Ind Yes
Stress Subtype Other
Stress Details Overload Fracture Induced By External Bending And/or Tensile Forces.
Additional Crack Ind Yes
Collected Data Ind No
Has Hydrtst Conduc Before Ind No
Direct Asmnt Conducted No
Non Destructive Exam Ind No
Preparer Name Z****** R*****
Preparer Title Engineer - Pipline
Preparer Email Z*************@k***********.com
Preparer Telephone 7134206633
Authorizer Name Z****** R*****
Authorizer Title Engineer - Pipline
Authorizer Telephone 7134206633
Authorizer Email Z*************@k***********.com
Narrative Tennessee gas pipeline (tgp) was notified on june 14, 2011, by boemre and by a producer, stone energy, of bubbles on the ocs in bay mar block 5, the coordinates of which indicated they were coming from tgp's pipeline facility. Upon investigation, divers removed protective mats from a subsea tie-in assembly on tgp's 524c-400 pipeline and found a crack in the neck of a 2" flange that was part of the tie-in of an intersecting pipeline. Repairs were made and the pipeline facility was placed back into service. Metallurgical analysis concluded that the crack in the weld of the 2" flange was likely due to overload fracture due to external bending and/or tensile forces. Such forces were possibly caused by instability of the subsea floor and concrete mats placed over assembly at time of construction. Year of pipe manufacture is assumed to be commensurate with year of installation.

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