GTG incident on 2010-01-10 — NE

Operator
Northern Natural Gas Co
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities 0 injuries
Property damage (nominal)
$464,000
Incident datetime
2010-01-10 21:24
Report number
Location
NE
Narrative
On january 10, 2010, at approximately 21:24 p.M. A fire was discovered, by a northern natural gas company employee, at the redfield underground storage field, located near redfield, iowa, in the sl peter underground storage formation at what is called the maher #3 well site in section 12, t19n, r29w, dallas county, iowa. There was no explosion, no injuries, no evacuations and no loss of service to customers. At approximately 24:00 hours the st peter formation pipeline system portion, of the storage field, was isolated and pressure was blown down on the piping to 5 psig to enable safe closure of the maher #3 well head valve (see page 2, item 15a). The fire was extinguished by 01:50 a.M. The fire destroyed the well house building and all of the components within the building but the well head valve and piping were unaffected. The portion of the st. Peter piping, that was isolated in order to facilitate reduction in pressure for the closure of the maher #3 well head valve, was return to normal operation pressures at approximately 12:00 a.M. On monday, january 11th (see page 2, item 15b). Preliminary results of a post incident investigation identified that the gas leakage appeared to be from a broken one-inch union on the well separator drain line. The union's threads appeared to be stripped or pulled. At the time of the event the ambient temperature was 21 degrees fahrenheit and the wind was out of the west at approximately 14 miles per hour. It is possible that freezing and heaving may have creating sufficient thermal stress which contributed to the separation of the threads on the one-inch union. The night before the failure there was an approximate low temperature of - 19 degrees fahrenheit in the area. Additional metallurgical failure analysis is being conducted to assist with determining whether thermal stress from the cold temperatures could be a root cause for stripping of the threads and the union's failure. Final report: a metallurgical examination of the failed one-inch union indicated that two portions of the union's threads demonstrated rolled damage to the top of the threads, which indicates the component pulled over the peak of the thread as it disengaged. An examination of the threads also indicates one flattened/rounded location that may have been damaged or improperly machined previous to the failure. The fitting was installed in 2006, and may have been faulty and the frozen condition of the drain line, on december 10, 2010, most likely created thermal stress, which resulted in failure of the fitting. As a measure to prevent recurrence, all well separator drain lines at the redfield, iowa underground storage facility were dissembled and inspected. No other issues or problems were found. The fire appears to have started immediately as there was no indication of an explosion. The wiring in the conduit, static electricity or sparks from the building structure or the one-inch pipe striking other piping when it separated was the likely ignition source. This event is considered complete and closed. Supplemental/final to report 20100019 per PHMSA request identified part e5f as transmission.
Detailed record list
Report Received Date
2010-05-04 00:00:00
Iyear
2010
Report Number
20100019
Supplemental Number
15761
Report Type
Supplemental Final
Operator Id
Name
Northern Natural Gas Co
Operator Street Address
1111 South 103rd Street
Operator City Name
Omaha
Operator State Abbreviation
NE
Operator Postal Code
68124
Local Datetime
2010-01-10 21:24:00
Location Latitude
Location Longitude
Nrc Rpt Num
Nrc Rpt Datetime
2010-01-10 23:50:00
Commodity Released Type
Natural Gas
Unintentional Release
1970
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Shutdown Due Accident Ind
Yes
Shutdown Datetime
2010-01-11 00:00:00
Restart Datetime
2010-01-11 12:00:00
Ignite Ind
Yes
Explode Ind
No
Num Pub Evacuated
0
Incident Identified Datetime
2010-01-10 21:24:00
On Site Datetime
2010-01-10 21:40:00
On Off Shore
Onshore
Onshore State Abbreviation
Ia
Onshore Postal Code
50233
Onshore City Name
Redfield
Onshore County Name
Dallas
Designated Location
Survey Station No.
Designated Name
Sec12t79nr29w
Pipe Fac Name
Redfield Maher #3 Well Site
Segment Name
St. Peter Underground Storage Fid System
Federal
No
Location Type
Operator-Controlled Property
Incident Area Type
Aboveground
Incident Area Subtype
Inside A Building
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Belowground Storage, Including Associated Equipment And Piping
Item Involved
Drain Lines
Installation Year
2006
Material Involved
Carbon Steel
Release Type
Leak
Leak Type
Connection Failure
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
75
Heat Damage Ind
No
Non Heat Damage Ind
No
Hca Fatalities Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
11600
Est Cost Intentional Release
0
Est Cost Prop Damage
464000
Est Cost Emergency
3500
Est Cost Other
0
Prpty
479100
Accident Psig
420
Mop Psig
960
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
Ground Patrol By Operator Or Its Contractor
Operator Type
Operator Employee
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
A northern natural gas company post incident investigation determined that the primary cause of the incident was gas leaking from a 1-lnch union of which controller's did not have any monitoring capability or control over. The controller did indicate that the maher #3 well site had an indication of a pressure drop then a loss of communications alarm at the location, which the on-site ground patrol was checking on during the field facilities check.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Equipment Failure
Cause Details
Threaded Connection/coupling Failure
Eq Failure Type
Threaded Connection/coupling Failure
Other Stripped Ind
Mechanical Coupling
Eq Additional Thermal Ind
Yes
Preparer Name
B**** H* W***
Preparer Title
Sr. Pipeline Safety Specialist
Preparer Email
B*********@n****.com
Preparer Telephone
402-398-7396
Preparer Fax
402-398-7606
Authorizer Name
T***** G* C******
Authorizer Title
Director. Pipeline Safety And Integrity
Authorizer Telephone
402-398-7715
Authorizer Email
T*************@n****.com
Narrative
On january 10, 2010, at approximately 21:24 p.M. A fire was discovered, by a northern natural gas company employee, at the redfield underground storage field, located near redfield, iowa, in the sl peter underground storage formation at what is called the maher #3 well site in section 12, t19n, r29w, dallas county, iowa. There was no explosion, no injuries, no evacuations and no loss of service to customers. At approximately 24:00 hours the st peter formation pipeline system portion, of the storage field, was isolated and pressure was blown down on the piping to 5 psig to enable safe closure of the maher #3 well head valve (see page 2, item 15a). The fire was extinguished by 01:50 a.M. The fire destroyed the well house building and all of the components within the building but the well head valve and piping were unaffected. The portion of the st. Peter piping, that was isolated in order to facilitate reduction in pressure for the closure of the maher #3 well head valve, was return to normal operation pressures at approximately 12:00 a.M. On monday, january 11th (see page 2, item 15b). Preliminary results of a post incident investigation identified that the gas leakage appeared to be from a broken one-inch union on the well separator drain line. The union's threads appeared to be stripped or pulled. At the time of the event the ambient temperature was 21 degrees fahrenheit and the wind was out of the west at approximately 14 miles per hour. It is possible that freezing and heaving may have creating sufficient thermal stress which contributed to the separation of the threads on the one-inch union. The night before the failure there was an approximate low temperature of - 19 degrees fahrenheit in the area. Additional metallurgical failure analysis is being conducted to assist with determining whether thermal stress from the cold temperatures could be a root cause for stripping of the threads and the union's failure. Final report: a metallurgical examination of the failed one-inch union indicated that two portions of the union's threads demonstrated rolled damage to the top of the threads, which indicates the component pulled over the peak of the thread as it disengaged. An examination of the threads also indicates one flattened/rounded location that may have been damaged or improperly machined previous to the failure. The fitting was installed in 2006, and may have been faulty and the frozen condition of the drain line, on december 10, 2010, most likely created thermal stress, which resulted in failure of the fitting. As a measure to prevent recurrence, all well separator drain lines at the redfield, iowa underground storage facility were dissembled and inspected. No other issues or problems were found. The fire appears to have started immediately as there was no indication of an explosion. The wiring in the conduit, static electricity or sparks from the building structure or the one-inch pipe striking other piping when it separated was the likely ignition source. This event is considered complete and closed. Supplemental/final to report 20100019 per PHMSA request identified part e5f as transmission.
Report Received Date 2010-05-04 00:00:00
Iyear 2010
Report Number 20100019
Supplemental Number 15761
Report Type Supplemental Final
Operator Id 13750 PHMSA Enforcement
Name Northern Natural Gas Co
Operator Street Address 1111 South 103rd Street
Operator City Name Omaha
Operator State Abbreviation NE
Operator Postal Code 68124
Local Datetime 2010-01-10 21:24:00
Location Latitude 41.66949 Google Maps OpenStreetMap
Location Longitude -94.1691 Google Maps OpenStreetMap
Nrc Rpt Num 928196 NRC Report How to search
Nrc Rpt Datetime 2010-01-10 23:50:00
Commodity Released Type Natural Gas
Unintentional Release 1970
Fatality Ind No
Fatal 0
Injury Ind No
Injure 0
Shutdown Due Accident Ind Yes
Shutdown Datetime 2010-01-11 00:00:00
Restart Datetime 2010-01-11 12:00:00
Ignite Ind Yes
Explode Ind No
Num Pub Evacuated 0
Incident Identified Datetime 2010-01-10 21:24:00
On Site Datetime 2010-01-10 21:40:00
On Off Shore Onshore
Onshore State Abbreviation Ia
Onshore Postal Code 50233
Onshore City Name Redfield
Onshore County Name Dallas
Designated Location Survey Station No.
Designated Name Sec12t79nr29w
Pipe Fac Name Redfield Maher #3 Well Site
Segment Name St. Peter Underground Storage Fid System
Federal No
Location Type Operator-Controlled Property
Incident Area Type Aboveground
Incident Area Subtype Inside A Building
Crossing No
Pipe Facility Type Interstate
System Part Involved Belowground Storage, Including Associated Equipment And Piping
Item Involved Drain Lines
Installation Year 2006
Material Involved Carbon Steel
Release Type Leak
Leak Type Connection Failure
Class Location Type Class 1 Location
Could Be Hca No
Pir Radius 75
Heat Damage Ind No
Non Heat Damage Ind No
Hca Fatalities Ind No
Est Cost Oper Paid 0
Est Cost Unintentional Release 11600
Est Cost Intentional Release 0
Est Cost Prop Damage 464000
Est Cost Emergency 3500
Est Cost Other 0
Prpty 479100
Accident Psig 420
Mop Psig 960
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 Ground Patrol By Operator Or Its Contractor
Operator Type Operator Employee
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 A northern natural gas company post incident investigation determined that the primary cause of the incident was gas leaking from a 1-lnch union of which controller's did not have any monitoring capability or control over. The controller did indicate that the maher #3 well site had an indication of a pressure drop then a loss of communications alarm at the location, which the on-site ground patrol was checking on during the field facilities check.
Employee Drug Test Ind No
Contractor Drug Test Ind No
Cause Equipment Failure
Cause Details Threaded Connection/coupling Failure
Eq Failure Type Threaded Connection/coupling Failure
Other Stripped Ind Mechanical Coupling
Eq Additional Thermal Ind Yes
Preparer Name B**** H* W***
Preparer Title Sr. Pipeline Safety Specialist
Preparer Email B*********@n****.com
Preparer Telephone 402-398-7396
Preparer Fax 402-398-7606
Authorizer Name T***** G* C******
Authorizer Title Director. Pipeline Safety And Integrity
Authorizer Telephone 402-398-7715
Authorizer Email T*************@n****.com
Narrative On january 10, 2010, at approximately 21:24 p.M. A fire was discovered, by a northern natural gas company employee, at the redfield underground storage field, located near redfield, iowa, in the sl peter underground storage formation at what is called the maher #3 well site in section 12, t19n, r29w, dallas county, iowa. There was no explosion, no injuries, no evacuations and no loss of service to customers. At approximately 24:00 hours the st peter formation pipeline system portion, of the storage field, was isolated and pressure was blown down on the piping to 5 psig to enable safe closure of the maher #3 well head valve (see page 2, item 15a). The fire was extinguished by 01:50 a.M. The fire destroyed the well house building and all of the components within the building but the well head valve and piping were unaffected. The portion of the st. Peter piping, that was isolated in order to facilitate reduction in pressure for the closure of the maher #3 well head valve, was return to normal operation pressures at approximately 12:00 a.M. On monday, january 11th (see page 2, item 15b). Preliminary results of a post incident investigation identified that the gas leakage appeared to be from a broken one-inch union on the well separator drain line. The union's threads appeared to be stripped or pulled. At the time of the event the ambient temperature was 21 degrees fahrenheit and the wind was out of the west at approximately 14 miles per hour. It is possible that freezing and heaving may have creating sufficient thermal stress which contributed to the separation of the threads on the one-inch union. The night before the failure there was an approximate low temperature of - 19 degrees fahrenheit in the area. Additional metallurgical failure analysis is being conducted to assist with determining whether thermal stress from the cold temperatures could be a root cause for stripping of the threads and the union's failure. Final report: a metallurgical examination of the failed one-inch union indicated that two portions of the union's threads demonstrated rolled damage to the top of the threads, which indicates the component pulled over the peak of the thread as it disengaged. An examination of the threads also indicates one flattened/rounded location that may have been damaged or improperly machined previous to the failure. The fitting was installed in 2006, and may have been faulty and the frozen condition of the drain line, on december 10, 2010, most likely created thermal stress, which resulted in failure of the fitting. As a measure to prevent recurrence, all well separator drain lines at the redfield, iowa underground storage facility were dissembled and inspected. No other issues or problems were found. The fire appears to have started immediately as there was no indication of an explosion. The wiring in the conduit, static electricity or sparks from the building structure or the one-inch pipe striking other piping when it separated was the likely ignition source. This event is considered complete and closed. Supplemental/final to report 20100019 per PHMSA request identified part e5f as transmission.

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