Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2015-09-05 — TX
Operator
Great Lakes Gas Transmission Co
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$520,000
Incident datetime
2015-09-05 20:50
Report number
Location
TX
Narrative
On september 5, 2015, great lakes gas transmission company (glgt) experienced an incident on its 200 line pipeline immediately downstream of a pig launcher on property controlled by glgt at its st. Vincent compressor station in kittson county, minnesota. The incident, which resulted in a shutdown of the pipeline valve section between the compressor station and mlv 1-1-2, was the result of a connection failure of a two-inch diameter pig signal component at the abovementioned location. Gas was released and subsequently ignited. Following control of the release and controlled blowdown of the pipeline section, the area was excavated and the source of the gas leak confirmed as a failed connection between the base of a pig signal offtake tube and a bolted mounting plate attached to the glgt 200 line. The damaged pig signal components, including the pig signal offtake tube with associated base (which was already disconnected from the pipeline) and the lower mounting plate, were removed from the pipeline and sent to a third-party laboratory for failure analysis. The pig signal was not replaced. The pipeline was repaired by removal of the weld-o-let that connected the base mounting plate to the pipeline and then installing a contoured insert fitting (vesselet) and cap. Following completion of the repair, the pipeline was placed back into service the afternoon of september 22, 2015. Failure analysis of the pig signal components indicated that three (3) of the four (4) fasteners, socket head cap screws (shcs), of the bolted mounting plate connection failed by a time-dependent, stress corrosion cracking (scc) mechanism. The west shcs failure may have been exacerbated by additional factors due to its very high hardness and possible un-tempered martensitic condition. The south shcs failed last and exhibited with mixed scc and ductile rupture modes. Its remaining ligament failed suddenly when its load bearing capacity was exceeded.
Detailed record list
Report Received Date
2015-10-05 00:00:00
Iyear
2015
Report Number
20150118
Supplemental Number
17097
Report Type
Supplemental Final
Operator Id
6660
Name
Great Lakes Gas Transmission Co
Operator Street Address
700 Louisiana Street Suite 700
Operator City Name
Houston
Operator State Abbreviation
TX
Operator Postal Code
77002
Local Datetime
2015-09-05 20:50:00
Location Latitude
48.990292
Location Longitude
-97.059182
Nrc Rpt Num
1127708
Nrc Rpt Datetime
2015-09-05 22:07:00
Commodity Released Type
Natural Gas
Unintentional Release
7260
Intentional Release
26610
Accompanying Liquid
0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Shutdown Due Accident Ind
Yes
Shutdown Datetime
2015-09-05 21:19:00
Restart Datetime
2015-09-22 16:20:00
Ignite Ind
Yes
Explode Ind
No
Num Pub Evacuated
2
Incident Identified Datetime
2015-09-05 20:50:00
On Site Datetime
2015-09-05 21:15:00
On Off Shore
Onshore
Onshore State Abbreviation
Mn
Onshore Postal Code
56755
Onshore City Name
Not Within A Municipality
Onshore County Name
Kittson
Designated Location
Milepost
Designated Name
Mp 0.7
Pipe Fac Name
200 Line
Segment Name
Valve Section 1-0-2
Federal
No
Location Type
Operator-Controlled Property
Incident Area Type
Underground
Incident Area Subtype
Under Soil
Depth Of Cover
40
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Onshore Pipeline, Including Valve Sites
Item Involved
Other
Item Involved Details
Pig Signal
Installation Year
1972
Material Involved
Carbon Steel
Release Type
Leak
Leak Type
Connection Failure
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
835
Heat Damage Ind
No
Non Heat Damage Ind
No
Hca Fatalities Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
19380
Est Cost Intentional Release
71050
Est Cost Prop Damage
520000
Est Cost Emergency
80000
Est Cost Other
0
Prpty
690430
Accident Psig
794
Mop Psig
974
Mop Cfr Section
192.619(A)(2)
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Upstream Valve Type Ind
Remotely Controlled
Downstream Valve Type Ind
Automatic
Length Segment Isolated
86275
Internal Inspection Ind
Yes
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
Notification From Emergency Responder
Investigation Status
Yes, specify investigation result(s): (select all that apply)
Invest Schedule Ind
Yes
Invest No Control Room Ind
Yes
Invest No Controller Ind
Yes
Employee Drug Test Ind
Yes
Contractor Drug Test Ind
No
Num Employees Tested
1
Num Employees Failed
0
Cause
Equipment Failure
Cause Details
Threaded Connection/coupling Failure
Eq Failure Type
Threaded Connection/coupling Failure
Other Stripped Ind
Mechanical Coupling
Eq Additional Other Ind
Yes
Eq Additional Other Details
Connection Socket Head Cap Screws Failed Due To Stress Corrosion Cracking
Preparer Name
R***** C******
Preparer Title
Compliance Specialist
Preparer Email
R*************@t**********.com
Preparer Telephone
248-205-7669
Authorizer Name
R***** C******
Authorizer Title
Compliance Specialist
Authorizer Telephone
248-205-7669
Authorizer Email
R*************@t**********.com
Narrative
On september 5, 2015, great lakes gas transmission company (glgt) experienced an incident on its 200 line pipeline immediately downstream of a pig launcher on property controlled by glgt at its st. Vincent compressor station in kittson county, minnesota. The incident, which resulted in a shutdown of the pipeline valve section between the compressor station and mlv 1-1-2, was the result of a connection failure of a two-inch diameter pig signal component at the abovementioned location. Gas was released and subsequently ignited. Following control of the release and controlled blowdown of the pipeline section, the area was excavated and the source of the gas leak confirmed as a failed connection between the base of a pig signal offtake tube and a bolted mounting plate attached to the glgt 200 line. The damaged pig signal components, including the pig signal offtake tube with associated base (which was already disconnected from the pipeline) and the lower mounting plate, were removed from the pipeline and sent to a third-party laboratory for failure analysis. The pig signal was not replaced. The pipeline was repaired by removal of the weld-o-let that connected the base mounting plate to the pipeline and then installing a contoured insert fitting (vesselet) and cap. Following completion of the repair, the pipeline was placed back into service the afternoon of september 22, 2015. Failure analysis of the pig signal components indicated that three (3) of the four (4) fasteners, socket head cap screws (shcs), of the bolted mounting plate connection failed by a time-dependent, stress corrosion cracking (scc) mechanism. The west shcs failure may have been exacerbated by additional factors due to its very high hardness and possible un-tempered martensitic condition. The south shcs failed last and exhibited with mixed scc and ductile rupture modes. Its remaining ligament failed suddenly when its load bearing capacity was exceeded.
| Report Received Date | 2015-10-05 00:00:00 |
|---|---|
| Iyear | 2015 |
| Report Number | 20150118 |
| Supplemental Number | 17097 |
| Report Type | Supplemental Final |
| Operator Id | 6660 PHMSA Enforcement |
| Name | Great Lakes Gas Transmission Co |
| Operator Street Address | 700 Louisiana Street Suite 700 |
| Operator City Name | Houston |
| Operator State Abbreviation | TX |
| Operator Postal Code | 77002 |
| Local Datetime | 2015-09-05 20:50:00 |
| Location Latitude | 48.990292 Google Maps OpenStreetMap |
| Location Longitude | -97.059182 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1127708 NRC Report How to search |
| Nrc Rpt Datetime | 2015-09-05 22:07:00 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 7260 |
| Intentional Release | 26610 |
| Accompanying Liquid | 0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Shutdown Due Accident Ind | Yes |
| Shutdown Datetime | 2015-09-05 21:19:00 |
| Restart Datetime | 2015-09-22 16:20:00 |
| Ignite Ind | Yes |
| Explode Ind | No |
| Num Pub Evacuated | 2 |
| Incident Identified Datetime | 2015-09-05 20:50:00 |
| On Site Datetime | 2015-09-05 21:15:00 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Mn |
| Onshore Postal Code | 56755 |
| Onshore City Name | Not Within A Municipality |
| Onshore County Name | Kittson |
| Designated Location | Milepost |
| Designated Name | Mp 0.7 |
| Pipe Fac Name | 200 Line |
| Segment Name | Valve Section 1-0-2 |
| Federal | No |
| Location Type | Operator-Controlled Property |
| Incident Area Type | Underground |
| Incident Area Subtype | Under Soil |
| Depth Of Cover | 40 |
| Crossing | No |
| Pipe Facility Type | Interstate |
| System Part Involved | Onshore Pipeline, Including Valve Sites |
| Item Involved | Other |
| Item Involved Details | Pig Signal |
| Installation Year | 1972 |
| Material Involved | Carbon Steel |
| Release Type | Leak |
| Leak Type | Connection Failure |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 835 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Hca Fatalities Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 19380 |
| Est Cost Intentional Release | 71050 |
| Est Cost Prop Damage | 520000 |
| Est Cost Emergency | 80000 |
| Est Cost Other | 0 |
| Prpty | 690430 |
| Accident Psig | 794 |
| Mop Psig | 974 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Pressure Restriction Ind | No |
| Upstream Valve Type Ind | Remotely Controlled |
| Downstream Valve Type Ind | Automatic |
| Length Segment Isolated | 86275 |
| Internal Inspection Ind | Yes |
| 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 | Notification From Emergency Responder |
| Investigation Status | Yes, specify investigation result(s): (select all that apply) |
| Invest Schedule Ind | Yes |
| Invest No Control Room Ind | Yes |
| Invest No Controller Ind | Yes |
| Employee Drug Test Ind | Yes |
| Contractor Drug Test Ind | No |
| Num Employees Tested | 1 |
| Num Employees Failed | 0 |
| Cause | Equipment Failure |
| Cause Details | Threaded Connection/coupling Failure |
| Eq Failure Type | Threaded Connection/coupling Failure |
| Other Stripped Ind | Mechanical Coupling |
| Eq Additional Other Ind | Yes |
| Eq Additional Other Details | Connection Socket Head Cap Screws Failed Due To Stress Corrosion Cracking |
| Preparer Name | R***** C****** |
| Preparer Title | Compliance Specialist |
| Preparer Email | R*************@t**********.com |
| Preparer Telephone | 248-205-7669 |
| Authorizer Name | R***** C****** |
| Authorizer Title | Compliance Specialist |
| Authorizer Telephone | 248-205-7669 |
| Authorizer Email | R*************@t**********.com |
| Narrative | On september 5, 2015, great lakes gas transmission company (glgt) experienced an incident on its 200 line pipeline immediately downstream of a pig launcher on property controlled by glgt at its st. Vincent compressor station in kittson county, minnesota. The incident, which resulted in a shutdown of the pipeline valve section between the compressor station and mlv 1-1-2, was the result of a connection failure of a two-inch diameter pig signal component at the abovementioned location. Gas was released and subsequently ignited. Following control of the release and controlled blowdown of the pipeline section, the area was excavated and the source of the gas leak confirmed as a failed connection between the base of a pig signal offtake tube and a bolted mounting plate attached to the glgt 200 line. The damaged pig signal components, including the pig signal offtake tube with associated base (which was already disconnected from the pipeline) and the lower mounting plate, were removed from the pipeline and sent to a third-party laboratory for failure analysis. The pig signal was not replaced. The pipeline was repaired by removal of the weld-o-let that connected the base mounting plate to the pipeline and then installing a contoured insert fitting (vesselet) and cap. Following completion of the repair, the pipeline was placed back into service the afternoon of september 22, 2015. Failure analysis of the pig signal components indicated that three (3) of the four (4) fasteners, socket head cap screws (shcs), of the bolted mounting plate connection failed by a time-dependent, stress corrosion cracking (scc) mechanism. The west shcs failure may have been exacerbated by additional factors due to its very high hardness and possible un-tempered martensitic condition. The south shcs failed last and exhibited with mixed scc and ductile rupture modes. Its remaining ligament failed suddenly when its load bearing capacity was exceeded. |
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