Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2022-01-02 — NE
Operator
Northern Natural Gas Co
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$300
Incident datetime
2022-01-02 17:20
Report number
Location
NE
Narrative
On january 2, 2022, at 1800 hours, the operator was notified by a passerby of a loud noise near the omaha 1st branch line regulator. Technicians arrived on site and found a relief valve venting at approximately 1920 hours. Pressure was verified to be normal (setpoint 460 psig) downstream of the regulators. Technicians isolated the relief valve at 1930 hours and returned the relief valve to service at 0030 hours january 3, 2022. Investigation concluded that moisture buildup in the relief valve pilot sense line started freezing due to ambient temperatures, causing ice to form in the sense line and increase pressure to the pilot assembly. This ice buildup caused the relief to vent below the setpoint. Additionally, a sliver of material prevented the seal on the relief valve to close. The site was checked regularly for reoccurrence with no new concerns found. The investigation was shared with other teams to evaluate similar scenarios.
Detailed record list
Report Received Date
2022-01-07 00:00:00
Iyear
2022
Report Number
20220001
Supplemental Number
36289
Report Type
Supplemental Final
Operator Id
13750
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
2022-01-02 17:17:00
Time Zone
Central
Daylight Savings Ind
No
Location Latitude
40.966954
Location Longitude
-95.930216
Nrc Rpt Num
1325770
Nrc Rpt Datetime
2022-01-02 21:40:00
Additional Nrc Report Numbers
1325882
Commodity Released Type
Natural Gas
Unintentional Release
3510
Intentional Release
0
Accompanying Liquid
0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Status When Identified
Normal Operation, Includes Pauses During Maintenance
Shutdown Due Accident Ind
No
Shutdown Explain
The Relief Valve Was Isolated
Communication State Fed Ind
No
Ignite Ind
No
Num Pub Evacuated
0
Incident Identified Datetime
2022-01-02 17:20:00
On Site Datetime
2022-01-02 17:20:00
On Off Shore
Onshore
Onshore State Abbreviation
Ne
Onshore Postal Code
68048
Onshore City Name
Not Within A Municipality
Onshore County Name
Cass
Designated Location
Milepost
Designated Name
0.0
Pipe Fac Name
Omaha 1st Take-Off Regulator
Segment Name
Mynard Test Site
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 Regulator/metering Station Equipment And Piping
Item Involved
Valve
Valve Type
Relief Valve
Installation Year
2021
Manufactured Year
Unknown
Material Involved
Carbon Steel
Release Type
Other
Release Type Details
Relief Valve Caused By Debris
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
291
Heat Damage Ind
No
Non Heat Damage Ind
No
Did Occur In Mca Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
12622
Est Cost Intentional Release
0
Est Cost Prop Damage
300
Est Cost Emergency
0
Est Cost Other
0
Gas Cost In Mcf
3.596
Prpty
12922
Num Persons Hosp Not Ovnght
0
Num Injured Treated By Emt
0
Num Resident Building Affctd
0
Num Business Building Affctd
0
Wildlife Impact Ind
No
Accident Psig
460
Gas Flow In Pipe In Mcf
55000
Mop Psig
490
Mop Cfr Section
192.619(A)(2)
Maop Established Date
2004-08-12 00:00:00
Maop Reversal Flow Ind
No
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Gas Required Odorized 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 Public
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
Gas was releasing at a pressure below the alarms.
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
Moisture Caused The Pilot In The Regulator To Stop Adjusting
Preparer Name
D**** C*******
Preparer Email
D*************@n****.com
Preparer Telephone
4023987439
Authorizer Name
T** C******
Authorizer Telephone
4023987715
Authorizer Email
T*************@n****.com
Narrative
On january 2, 2022, at 1800 hours, the operator was notified by a passerby of a loud noise near the omaha 1st branch line regulator. Technicians arrived on site and found a relief valve venting at approximately 1920 hours. Pressure was verified to be normal (setpoint 460 psig) downstream of the regulators. Technicians isolated the relief valve at 1930 hours and returned the relief valve to service at 0030 hours january 3, 2022. Investigation concluded that moisture buildup in the relief valve pilot sense line started freezing due to ambient temperatures, causing ice to form in the sense line and increase pressure to the pilot assembly. This ice buildup caused the relief to vent below the setpoint. Additionally, a sliver of material prevented the seal on the relief valve to close. The site was checked regularly for reoccurrence with no new concerns found. The investigation was shared with other teams to evaluate similar scenarios.
| Report Received Date | 2022-01-07 00:00:00 |
|---|---|
| Iyear | 2022 |
| Report Number | 20220001 |
| Supplemental Number | 36289 |
| 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 | 2022-01-02 17:17:00 |
| Time Zone | Central |
| Daylight Savings Ind | No |
| Location Latitude | 40.966954 Google Maps OpenStreetMap |
| Location Longitude | -95.930216 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1325770 NRC Report How to search |
| Nrc Rpt Datetime | 2022-01-02 21:40:00 |
| Additional Nrc Report Numbers | 1325882 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 3510 |
| Intentional Release | 0 |
| Accompanying Liquid | 0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Status When Identified | Normal Operation, Includes Pauses During Maintenance |
| Shutdown Due Accident Ind | No |
| Shutdown Explain | The Relief Valve Was Isolated |
| Communication State Fed Ind | No |
| Ignite Ind | No |
| Num Pub Evacuated | 0 |
| Incident Identified Datetime | 2022-01-02 17:20:00 |
| On Site Datetime | 2022-01-02 17:20:00 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Ne |
| Onshore Postal Code | 68048 |
| Onshore City Name | Not Within A Municipality |
| Onshore County Name | Cass |
| Designated Location | Milepost |
| Designated Name | 0.0 |
| Pipe Fac Name | Omaha 1st Take-Off Regulator |
| Segment Name | Mynard Test Site |
| 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 Regulator/metering Station Equipment And Piping |
| Item Involved | Valve |
| Valve Type | Relief Valve |
| Installation Year | 2021 |
| Manufactured Year | Unknown |
| Material Involved | Carbon Steel |
| Release Type | Other |
| Release Type Details | Relief Valve Caused By Debris |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 291 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Did Occur In Mca Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 12622 |
| Est Cost Intentional Release | 0 |
| Est Cost Prop Damage | 300 |
| Est Cost Emergency | 0 |
| Est Cost Other | 0 |
| Gas Cost In Mcf | 3.596 |
| Prpty | 12922 |
| Num Persons Hosp Not Ovnght | 0 |
| Num Injured Treated By Emt | 0 |
| Num Resident Building Affctd | 0 |
| Num Business Building Affctd | 0 |
| Wildlife Impact Ind | No |
| Accident Psig | 460 |
| Gas Flow In Pipe In Mcf | 55000 |
| Mop Psig | 490 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Maop Established Date | 2004-08-12 00:00:00 |
| Maop Reversal Flow Ind | No |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Pressure Restriction Ind | No |
| Gas Required Odorized 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 Public |
| 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 | Gas was releasing at a pressure below the alarms. |
| 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 | Moisture Caused The Pilot In The Regulator To Stop Adjusting |
| Preparer Name | D**** C******* |
| Preparer Email | D*************@n****.com |
| Preparer Telephone | 4023987439 |
| Authorizer Name | T** C****** |
| Authorizer Telephone | 4023987715 |
| Authorizer Email | T*************@n****.com |
| Narrative | On january 2, 2022, at 1800 hours, the operator was notified by a passerby of a loud noise near the omaha 1st branch line regulator. Technicians arrived on site and found a relief valve venting at approximately 1920 hours. Pressure was verified to be normal (setpoint 460 psig) downstream of the regulators. Technicians isolated the relief valve at 1930 hours and returned the relief valve to service at 0030 hours january 3, 2022. Investigation concluded that moisture buildup in the relief valve pilot sense line started freezing due to ambient temperatures, causing ice to form in the sense line and increase pressure to the pilot assembly. This ice buildup caused the relief to vent below the setpoint. Additionally, a sliver of material prevented the seal on the relief valve to close. The site was checked regularly for reoccurrence with no new concerns found. The investigation was shared with other teams to evaluate similar scenarios. |
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