Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2011-10-06 — ND
Operator
Williston Basin Interstate Pipeline Co
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$2
Incident datetime
2011-10-06 00:46
Report number
Location
ND
Narrative
A downstream station regulator #6 (r6) went closed due to the warm night temperatures which required a minimal amount of gas to hold the billings line. The upstream regulator #5 (r5)was leaking enough gas to create an excess pressure build up on the "shut-in" dry bed dehy inlet piping. Relief valve #12 (rv12) opened as designed at a scada reported pressure of 719 psig to protect the maop (720 psig) of the dry bed dehy piping. After the relief valve opened releasing gas, a 1/4 inch pipe nipple broke off on the relief valve piping supplying pilot gas to the relief valve. The pipe nipple that failed supplied pilot gas to the relief valve which resulted in lost pilot pressure and prevented the relief valve from reseating. Once the operator reached the station, the dehy pressure was verified and the valve supplying gas to the relief valve and pilot valve was closed. The dehy was then shut in. According to scada trending, gas vented for 1 hr and 15 minutes. The estimated volume released was calculated to be approximately 3,800 mcf which exceeds the reportable incident threshold of 3,000 mcf. The overpressure condition resulted from a leaking regulator, not by actions of the gas controller or station personnel. Gas control does not have supervisory control of any station regulators and the station was unattended at the time of the incident. The pir calculated in this report was based on a 3" blow down stack and 720 psig maop. Appended part e5f to transmission system per DOT email request from blaine keener on 3/4/13.
Detailed record list
Report Received Date
2011-11-02 00:00:00
Iyear
2011
Report Number
20110383
Supplemental Number
15824
Report Type
Supplemental Final
Operator Id
22655
Name
Williston Basin Interstate Pipeline Co
Operator Street Address
1250 West Century Avenue
Operator City Name
Bismarck
Operator State Abbreviation
ND
Operator Postal Code
58503
Local Datetime
2011-10-06 00:46:00
Location Latitude
44.991913
Location Longitude
-108.86707
Nrc Rpt Num
991743
Nrc Rpt Datetime
2011-10-06 06:03:00
Commodity Released Type
Natural Gas
Unintentional Release
3800
Intentional Release
0
Accompanying Liquid
0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Shutdown Due Accident Ind
No
Shutdown Explain
The Release Point Was Isolated And Shut In.
Ignite Ind
No
Explode Ind
No
Num Pub Evacuated
0
Incident Identified Datetime
2011-10-06 00:46:00
On Site Datetime
2011-10-06 01:34:00
On Off Shore
Onshore
Onshore State Abbreviation
Wy
Onshore Postal Code
82435-1164
Onshore City Name
Powell
Onshore County Name
Park
Designated Location
Survey Station No.
Designated Name
0+00
Pipe Fac Name
Elk Basin Compressor Station
Segment Name
Elk Basin Compressor Station
Federal
No
Location Type
Operator-Controlled Property
Incident Area Type
Aboveground
Incident Area Subtype
Typical Aboveground Facility Piping Or Appurtenance
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Onshore Compressor Station Equipment And Piping
Item Involved
Esd System, But Excluding Product Drain Lines And Tubing
Installation Year
1981
Material Involved
Carbon Steel
Release Type
Other
Release Type Details
A Relief Valve Opened As Designed. After The Relief Valve Opened, A 1/4" Nipple Supplying Pilot Gas To The Relief Valve Failed Which Prevented The Relief Valve From Reseating.
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
56
Heat Damage Ind
No
Non Heat Damage Ind
No
Hca Fatalities Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
13448
Est Cost Intentional Release
0
Est Cost Prop Damage
2
Est Cost Emergency
81
Est Cost Other
0
Prpty
13531
Accident Psig
719
Mop Psig
720
Mop Cfr Section
Not On Omb-Approved Form When Submitted
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Pipeline Function
Transmission System
Scada In Place Ind
Yes
Scada Operating Ind
Yes
Scada Functional Ind
Yes
Scada Detection Ind
Yes
Scada Conf Ind
Yes
Accident Identifier
Scada-Based Information (Such As Alarm(S), Alert(S), Event(S), And/or Volume Or Pack Calculations)
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
No
Contractor Drug Test Ind
No
Cause
Equipment Failure
Cause Details
Malfunction Of Control/relief Equipment
Eq Failure Type
Malfunction Of Control/relief Equipment
Relief Valve Ind
Yes
Eq Additional Other Ind
Yes
Eq Additional Other Details
Relief Valve Failed To Reseat/close After Pressure Was Relieved.
Preparer Name
K*** K***
Preparer Title
Engineer
Preparer Email
K********@w********.com
Preparer Telephone
406-359-7222
Preparer Fax
406-359-7244
Authorizer Name
K*** K***
Authorizer Title
Dot Compliance Supervisor
Authorizer Telephone
406-359-7222
Authorizer Email
K********@w********.com
Narrative
A downstream station regulator #6 (r6) went closed due to the warm night temperatures which required a minimal amount of gas to hold the billings line. The upstream regulator #5 (r5)was leaking enough gas to create an excess pressure build up on the "shut-in" dry bed dehy inlet piping. Relief valve #12 (rv12) opened as designed at a scada reported pressure of 719 psig to protect the maop (720 psig) of the dry bed dehy piping. After the relief valve opened releasing gas, a 1/4 inch pipe nipple broke off on the relief valve piping supplying pilot gas to the relief valve. The pipe nipple that failed supplied pilot gas to the relief valve which resulted in lost pilot pressure and prevented the relief valve from reseating. Once the operator reached the station, the dehy pressure was verified and the valve supplying gas to the relief valve and pilot valve was closed. The dehy was then shut in. According to scada trending, gas vented for 1 hr and 15 minutes. The estimated volume released was calculated to be approximately 3,800 mcf which exceeds the reportable incident threshold of 3,000 mcf. The overpressure condition resulted from a leaking regulator, not by actions of the gas controller or station personnel. Gas control does not have supervisory control of any station regulators and the station was unattended at the time of the incident. The pir calculated in this report was based on a 3" blow down stack and 720 psig maop. Appended part e5f to transmission system per DOT email request from blaine keener on 3/4/13.
| Report Received Date | 2011-11-02 00:00:00 |
|---|---|
| Iyear | 2011 |
| Report Number | 20110383 |
| Supplemental Number | 15824 |
| Report Type | Supplemental Final |
| Operator Id | 22655 PHMSA Enforcement |
| Name | Williston Basin Interstate Pipeline Co |
| Operator Street Address | 1250 West Century Avenue |
| Operator City Name | Bismarck |
| Operator State Abbreviation | ND |
| Operator Postal Code | 58503 |
| Local Datetime | 2011-10-06 00:46:00 |
| Location Latitude | 44.991913 Google Maps OpenStreetMap |
| Location Longitude | -108.86707 Google Maps OpenStreetMap |
| Nrc Rpt Num | 991743 NRC Report How to search |
| Nrc Rpt Datetime | 2011-10-06 06:03:00 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 3800 |
| Intentional Release | 0 |
| Accompanying Liquid | 0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Shutdown Due Accident Ind | No |
| Shutdown Explain | The Release Point Was Isolated And Shut In. |
| Ignite Ind | No |
| Explode Ind | No |
| Num Pub Evacuated | 0 |
| Incident Identified Datetime | 2011-10-06 00:46:00 |
| On Site Datetime | 2011-10-06 01:34:00 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Wy |
| Onshore Postal Code | 82435-1164 |
| Onshore City Name | Powell |
| Onshore County Name | Park |
| Designated Location | Survey Station No. |
| Designated Name | 0+00 |
| Pipe Fac Name | Elk Basin Compressor Station |
| Segment Name | Elk Basin Compressor Station |
| Federal | No |
| Location Type | Operator-Controlled Property |
| Incident Area Type | Aboveground |
| Incident Area Subtype | Typical Aboveground Facility Piping Or Appurtenance |
| Crossing | No |
| Pipe Facility Type | Interstate |
| System Part Involved | Onshore Compressor Station Equipment And Piping |
| Item Involved | Esd System, But Excluding Product Drain Lines And Tubing |
| Installation Year | 1981 |
| Material Involved | Carbon Steel |
| Release Type | Other |
| Release Type Details | A Relief Valve Opened As Designed. After The Relief Valve Opened, A 1/4" Nipple Supplying Pilot Gas To The Relief Valve Failed Which Prevented The Relief Valve From Reseating. |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 56 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Hca Fatalities Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 13448 |
| Est Cost Intentional Release | 0 |
| Est Cost Prop Damage | 2 |
| Est Cost Emergency | 81 |
| Est Cost Other | 0 |
| Prpty | 13531 |
| Accident Psig | 719 |
| Mop Psig | 720 |
| 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 |
| Pipeline Function | Transmission System |
| Scada In Place Ind | Yes |
| Scada Operating Ind | Yes |
| Scada Functional Ind | Yes |
| Scada Detection Ind | Yes |
| Scada Conf Ind | Yes |
| Accident Identifier | Scada-Based Information (Such As Alarm(S), Alert(S), Event(S), And/or Volume Or Pack Calculations) |
| 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 | No |
| Contractor Drug Test Ind | No |
| Cause | Equipment Failure |
| Cause Details | Malfunction Of Control/relief Equipment |
| Eq Failure Type | Malfunction Of Control/relief Equipment |
| Relief Valve Ind | Yes |
| Eq Additional Other Ind | Yes |
| Eq Additional Other Details | Relief Valve Failed To Reseat/close After Pressure Was Relieved. |
| Preparer Name | K*** K*** |
| Preparer Title | Engineer |
| Preparer Email | K********@w********.com |
| Preparer Telephone | 406-359-7222 |
| Preparer Fax | 406-359-7244 |
| Authorizer Name | K*** K*** |
| Authorizer Title | Dot Compliance Supervisor |
| Authorizer Telephone | 406-359-7222 |
| Authorizer Email | K********@w********.com |
| Narrative | A downstream station regulator #6 (r6) went closed due to the warm night temperatures which required a minimal amount of gas to hold the billings line. The upstream regulator #5 (r5)was leaking enough gas to create an excess pressure build up on the "shut-in" dry bed dehy inlet piping. Relief valve #12 (rv12) opened as designed at a scada reported pressure of 719 psig to protect the maop (720 psig) of the dry bed dehy piping. After the relief valve opened releasing gas, a 1/4 inch pipe nipple broke off on the relief valve piping supplying pilot gas to the relief valve. The pipe nipple that failed supplied pilot gas to the relief valve which resulted in lost pilot pressure and prevented the relief valve from reseating. Once the operator reached the station, the dehy pressure was verified and the valve supplying gas to the relief valve and pilot valve was closed. The dehy was then shut in. According to scada trending, gas vented for 1 hr and 15 minutes. The estimated volume released was calculated to be approximately 3,800 mcf which exceeds the reportable incident threshold of 3,000 mcf. The overpressure condition resulted from a leaking regulator, not by actions of the gas controller or station personnel. Gas control does not have supervisory control of any station regulators and the station was unattended at the time of the incident. The pir calculated in this report was based on a 3" blow down stack and 720 psig maop. Appended part e5f to transmission system per DOT email request from blaine keener on 3/4/13. |
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