Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2022-11-09 — TX
Operator
Northwest Pipeline Llc
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$800
Incident datetime
2022-11-09 06:45
Report number
Location
TX
Narrative
On november 9, 2022 operations personnel on site at the kemmerer compressor station heard what appeared to be a compressor relief valve relieving gas. Upon further investigation the operations technician discovered the unit 1 psv was relieving. In order to remedy the situation as quickly as possible, the technician shut the unit down, isolated it from pressure, and blew it down. It was noted by the technician at the time that the relief valve would not reseat itself after decreasing pressure. It was also noted that the relief valve had opened up prematurely at a pressure of around 770psi, where the set pressure on the relief valve was 928 psi. Since operations didn't know exactly when the relief valve started releasing gas, they worked with tech services and gas control to attempt to find any data signifying when the release started to occur. Hmi trends and station cctv cameras were utilized to try and determine when the unit started to relieve, but were unsuccessful in determining the exact time. After reviewing that data throughout the day on november 9th and not finding a definitive answer, it was decided to calculate a gas loss estimation from the moment the operator arrived on site at 06:45 to the time the unit was completely isolated and gas had stopped releasing at 07:22. Once this timeframe was decided, the gas loss calculation was promptly run and found to be in excess of the 3mmscf threshold. That gas loss estimation was then communicated to the security operations center at williams and was immediately reported to the nrc that afternoon. Over the course of the following weeks, operations worked with gas control, scada, and tech services to investigate why the valve had opened at a lower pressure than designed. It was discovered that the pilot on this psv failed due to a harmonic frequency at the station. In order to remedy the situation, operations worked to get a new and different pilot installed on this psv that wouldn't be susceptible to premature relieving as a result of harmonics. Operations successfully installed the new pilot on the psv and returned the compressor unit to service on 11/18/2022.
Detailed record list
Report Received Date
2022-12-01 00:00:00
Iyear
2022
Report Number
20220125
Supplemental Number
37423
Report Type
Supplemental Final
Operator Id
13845
Name
Northwest Pipeline Llc
Operator Street Address
2800 Post Oak Blvd
Operator City Name
Houston
Operator State Abbreviation
TX
Operator Postal Code
77056
Local Datetime
2022-11-09 07:14:00
Time Zone
Mountain
Daylight Savings Ind
No
Location Latitude
41.823264
Location Longitude
-110.789578
Nrc Rpt Num
1352168
Nrc Rpt Datetime
2022-11-09 16:54:00
Additional Nrc Report Numbers
1352310
Commodity Released Type
Natural Gas
Unintentional Release
3895
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
Just The Compressor Unit That Had The Relief Valve Discharge Was Shut Down.
Communication State Fed Ind
No
Ignite Ind
No
Num Pub Evacuated
0
Incident Identified Datetime
2022-11-09 06:45:00
On Site Datetime
2022-11-09 06:45:00
On Off Shore
Onshore
Onshore State Abbreviation
Wy
Onshore Postal Code
83101
Onshore City Name
Not Within A Municipality
Onshore County Name
Lincoln
Designated Location
Not Applicable
Pipe Fac Name
Nwp Kemmerer Compressor Station
Segment Name
Kemmerer Compressor Station
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
Onshore Compressor Station Equipment And Piping
Item Involved
Compressor
Installation Year
2019
Manufactured Year
Unknown
Material Involved
Carbon Steel
Release Type
Other
Release Type Details
Gas Released Via A Pressure Relief Valve
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
510
Heat Damage Ind
No
Non Heat Damage Ind
No
Did Occur In Mca Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
34977
Est Cost Intentional Release
0
Est Cost Prop Damage
800
Est Cost Emergency
0
Est Cost Other
0
Gas Cost In Mcf
8.98
Prpty
35777
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
776
Gas Flow In Pipe In Mcf
661000
Mop Psig
866
Mop Cfr Section
192.619(A)(2)
Maop Established Date
1956-12-01 00:00:00
Maop Reversal Flow Ind
Bi-Directional
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
Local Operating Personnel, Including Contractors
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
Psv activation was not due to a control room related failure.
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
Psv Pilot Was Found To Fail Due To Harmonics
Preparer Name
T***** K J*****
Preparer Title
Pipeline Safety Engineer
Preparer Email
T************@w*******.com
Preparer Telephone
2813828869
Authorizer Name
J*** B***
Authorizer Title
Pipeline Safety Manager
Authorizer Telephone
3373179145
Authorizer Email
J********@w*******.com
Narrative
On november 9, 2022 operations personnel on site at the kemmerer compressor station heard what appeared to be a compressor relief valve relieving gas. Upon further investigation the operations technician discovered the unit 1 psv was relieving. In order to remedy the situation as quickly as possible, the technician shut the unit down, isolated it from pressure, and blew it down. It was noted by the technician at the time that the relief valve would not reseat itself after decreasing pressure. It was also noted that the relief valve had opened up prematurely at a pressure of around 770psi, where the set pressure on the relief valve was 928 psi. Since operations didn't know exactly when the relief valve started releasing gas, they worked with tech services and gas control to attempt to find any data signifying when the release started to occur. Hmi trends and station cctv cameras were utilized to try and determine when the unit started to relieve, but were unsuccessful in determining the exact time. After reviewing that data throughout the day on november 9th and not finding a definitive answer, it was decided to calculate a gas loss estimation from the moment the operator arrived on site at 06:45 to the time the unit was completely isolated and gas had stopped releasing at 07:22. Once this timeframe was decided, the gas loss calculation was promptly run and found to be in excess of the 3mmscf threshold. That gas loss estimation was then communicated to the security operations center at williams and was immediately reported to the nrc that afternoon. Over the course of the following weeks, operations worked with gas control, scada, and tech services to investigate why the valve had opened at a lower pressure than designed. It was discovered that the pilot on this psv failed due to a harmonic frequency at the station. In order to remedy the situation, operations worked to get a new and different pilot installed on this psv that wouldn't be susceptible to premature relieving as a result of harmonics. Operations successfully installed the new pilot on the psv and returned the compressor unit to service on 11/18/2022.
| Report Received Date | 2022-12-01 00:00:00 |
|---|---|
| Iyear | 2022 |
| Report Number | 20220125 |
| Supplemental Number | 37423 |
| Report Type | Supplemental Final |
| Operator Id | 13845 PHMSA Enforcement |
| Name | Northwest Pipeline Llc |
| Operator Street Address | 2800 Post Oak Blvd |
| Operator City Name | Houston |
| Operator State Abbreviation | TX |
| Operator Postal Code | 77056 |
| Local Datetime | 2022-11-09 07:14:00 |
| Time Zone | Mountain |
| Daylight Savings Ind | No |
| Location Latitude | 41.823264 Google Maps OpenStreetMap |
| Location Longitude | -110.789578 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1352168 NRC Report How to search |
| Nrc Rpt Datetime | 2022-11-09 16:54:00 |
| Additional Nrc Report Numbers | 1352310 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 3895 |
| 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 | Just The Compressor Unit That Had The Relief Valve Discharge Was Shut Down. |
| Communication State Fed Ind | No |
| Ignite Ind | No |
| Num Pub Evacuated | 0 |
| Incident Identified Datetime | 2022-11-09 06:45:00 |
| On Site Datetime | 2022-11-09 06:45:00 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Wy |
| Onshore Postal Code | 83101 |
| Onshore City Name | Not Within A Municipality |
| Onshore County Name | Lincoln |
| Designated Location | Not Applicable |
| Pipe Fac Name | Nwp Kemmerer Compressor Station |
| Segment Name | Kemmerer Compressor Station |
| 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 | Onshore Compressor Station Equipment And Piping |
| Item Involved | Compressor |
| Installation Year | 2019 |
| Manufactured Year | Unknown |
| Material Involved | Carbon Steel |
| Release Type | Other |
| Release Type Details | Gas Released Via A Pressure Relief Valve |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 510 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Did Occur In Mca Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 34977 |
| Est Cost Intentional Release | 0 |
| Est Cost Prop Damage | 800 |
| Est Cost Emergency | 0 |
| Est Cost Other | 0 |
| Gas Cost In Mcf | 8.98 |
| Prpty | 35777 |
| 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 | 776 |
| Gas Flow In Pipe In Mcf | 661000 |
| Mop Psig | 866 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Maop Established Date | 1956-12-01 00:00:00 |
| Maop Reversal Flow Ind | Bi-Directional |
| 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 | Local Operating Personnel, Including Contractors |
| 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 | Psv activation was not due to a control room related failure. |
| 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 | Psv Pilot Was Found To Fail Due To Harmonics |
| Preparer Name | T***** K J***** |
| Preparer Title | Pipeline Safety Engineer |
| Preparer Email | T************@w*******.com |
| Preparer Telephone | 2813828869 |
| Authorizer Name | J*** B*** |
| Authorizer Title | Pipeline Safety Manager |
| Authorizer Telephone | 3373179145 |
| Authorizer Email | J********@w*******.com |
| Narrative | On november 9, 2022 operations personnel on site at the kemmerer compressor station heard what appeared to be a compressor relief valve relieving gas. Upon further investigation the operations technician discovered the unit 1 psv was relieving. In order to remedy the situation as quickly as possible, the technician shut the unit down, isolated it from pressure, and blew it down. It was noted by the technician at the time that the relief valve would not reseat itself after decreasing pressure. It was also noted that the relief valve had opened up prematurely at a pressure of around 770psi, where the set pressure on the relief valve was 928 psi. Since operations didn't know exactly when the relief valve started releasing gas, they worked with tech services and gas control to attempt to find any data signifying when the release started to occur. Hmi trends and station cctv cameras were utilized to try and determine when the unit started to relieve, but were unsuccessful in determining the exact time. After reviewing that data throughout the day on november 9th and not finding a definitive answer, it was decided to calculate a gas loss estimation from the moment the operator arrived on site at 06:45 to the time the unit was completely isolated and gas had stopped releasing at 07:22. Once this timeframe was decided, the gas loss calculation was promptly run and found to be in excess of the 3mmscf threshold. That gas loss estimation was then communicated to the security operations center at williams and was immediately reported to the nrc that afternoon. Over the course of the following weeks, operations worked with gas control, scada, and tech services to investigate why the valve had opened at a lower pressure than designed. It was discovered that the pilot on this psv failed due to a harmonic frequency at the station. In order to remedy the situation, operations worked to get a new and different pilot installed on this psv that wouldn't be susceptible to premature relieving as a result of harmonics. Operations successfully installed the new pilot on the psv and returned the compressor unit to service on 11/18/2022. |
External Resources
PHMSA pipeline safety insights.
Product
Features
Company
All rights reserved. Copyright © by ClearPHMSA