Incident details
Operator, cause, commodity and consequences with raw source fields.
GD incident on 2022-09-02 — CO
Operator
Walden, Town Of
Cause
Corrosion Failure
Commodity
Natural Gas
Program
GD
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$2,000
Incident datetime
2022-09-02 05:30
Report number
Location
CO, JACKSON
Narrative
On august 31, 2022 the walden pipeline operators received phone calls from the cig control center, about concerns for increased gas usage. Online flow records showed an apparent 10x flow increase around august 23. Cig had checked its delivery meter and found nothing abnormal. The 50-mile transmission system was systematically isolated and checked by section, and cig noted an abrupt drop in flow. The last section isolated was the high-pressure distribution system in colorado that feeds the town systems in cowdrey and walden.Next day we pinpointed low pressure on the 2-inch section that helps feed walden. This was the original supply line to walden, built ca 1958 of coated steel 2" pipe. We had found and fixed a corrosion pinhole leak on this segment earlier in july, the only leak found in 20+ years on any pipeline in colorado. This 17,000 ft segment was looped ca 1979 with a 3" coated steel line, parallel and about 10 ft southeast. The 2" section was isolated and quickly pressured down. Later, gas was reintroduced and a leak survey done in the area around the previous leak. The newer leak was detected about 180 ft sw of the previous repair, running along a shallow sagebrush wash. With this segment shut down and the 3" loop carrying the load, we excavated the new leak area on november 2, intending a repair. The pipe and coating looked identical to that with the nearby leak repair, but was very shallow. The excavated material was mostly black, smelly leak dirt indicative of a long-term gas leak. The excavator stripped out the pipe for 60 ft, and we introduced a small amount of gas from the nearby block valve. The exposed & cleaned-off pipeline didn't leak. But the gas detector picked up gas near the front and north side of the backhoe, well away from the exposed 2" and the side away from the 3" loop. After further investigation, digging out more leak dirt, we eventually found a second string of 2" pipe running parallel to the exposed line, about 7 ft nw and 3.5 ft deeper. We stripped out a 10-ft section of this newly-discovered pipe. The coating was a cold-applied yellow tape with thick black mastic, likely hand-applied with good overlaps and no wrinkles. We could find no obvious defects or holes, until gas was introduced. In less than 5 seconds, the short section appeared to leak in at least 4 places, including a pinkie-size hole in the tape and the pipe on the bottom. Although the tape looked good on first inspection, there were several deep marks and dents, although the soil was rock-free, moist clay. The deep dents may have been made during installation, when the pipe was lowered in with log chains instead of softer pipe slings. This 3rd line is not shown on any maps or described in any documents conveyed from the original owner rocky mountain natural gas to the town in 1995. With 5 corrosion leaks (despite good cp readings) in 200 ft in a few months; and with little hydraulic value, we decided to permanently abandon the 2-inch segment. We cut out an 8-ft section of the leaking pipe, and weld-capped both ends of the 17,000 ft segment, with documentation that this section can't be used again. This leak was about 1.2 miles from the edge of walden. The nearest public road is the county rodeo & fairgrounds about 1/2 mile away, and 0.9 mile to the nearest residence. We believe this leak has persisted for decades. It was not reported by the public, since it is very remote and the prevailing wind generally blows from the southwest, away from any residences or roads. The utility had leak-surveyed the 2 known parallel lines as required by DOT part 192. The vehicle-mounted rig was always driven between the 2 pipelines that are only 8 ft apart. The unknown line was about 12 ft outside the leak survey path. We believe old undetected pinhole leaks blew out with the re-pressurization after the previous repair. No injuries or deaths resulted from this leak. The only damage was the value of lost gas.
Detailed record list
Occurred At
2022-09-02 05:30:00
Year
2022
Report Received Date
2022-11-03 00:00:00
Iyear
2022.0
Report Number
20220070.0
Supplemental Number
37834.0
Report Type
Supplemental Final
Operator Id
30839
Name
Walden, Town Of
Operator Street Address
Po Box 489 513 Harrison St
Operator City Name
Walden
Operator State Abbreviation
CO
Operator Postal Code
80480
Local Datetime
2022-08-31 13:00:00
Time Zone
Mountain
Daylight Savings Ind
Yes
Location Street Address
0.5 Miles East Of Fair Grounds
Location City Name
Walden
Location County Name
Jackson
Location State Abbreviation
CO
Location Postal Code
80480
Location Latitude
40.746952
Location Longitude
-106.2604
Flow Cont Key Crit Ind
Yes
Nrc Rpt Datetime
2022-10-25 13:38:00
Nrc Rpt Num
1350815
Commodity Released Type
Natural Gas
Unintentional Release
6100.0
Intentional Release
0.0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Ignite Ind
No
Num Pub Evacuated
0.0
Incident Identified Datetime
2022-09-02 05:30:00
Communication State Fed Ind
No
On Site Datetime
2022-09-02 09:00:00
Federal
No
Location Type
Private Property
Incident Area Type
Underground
Incident Area Subtype
Under Soil
Depth Of Cover
60.0
Other Underground Facilities
No
Crossing
No
Pipe Facility Type
Municipally Owned
System Part Involved
Main
Installation Year
1970.0
Pipe Diameter
2.0
Pipe Specification
Unknown
Pipe Manufacturer
Unknown
Material Involved
Steel
Steel Seam Type
Longitudinal Erw - Unknown Frequency
Release Type
Leak
Leak Type
Pinhole
Class Location Type
Class 1 Location
Est Cost Oper Paid
0.0
Est Cost Prop Damage
2000.0
Est Cost Emergency
0.0
Est Cost Other
0.0
Gas Cost In Mcf
5.3514
Est Cost Unintentional Release
32644.0
Est Cost Intentional Release
0.0
Prpty
34644.0
Commercial Affected
0.0
Industrial Affected
0.0
Residences Affected
0.0
Num Persons Hosp Not Ovnght
0.0
Num Injured Treated By Emt
0.0
Num Resident Building Affctd
0.0
Num Business Building Affctd
0.0
Accident Psig
250.0
Normal Psig
15.0
Mop Psig
275.0
Mop Cfr Section
192.619(A)(2)
Maop Established Date
1995-04-15 00:00:00
Accident Pressure
Pressure Did Not Exceed Maop
Gas Odorized System Type
By-Pass
Gas Odorized Lvl Not Msrd Ind
Yes
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
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
The scada system is operated by the gas supplier (colorado interstate gas). They did not have reasonable alarms set for our system and notified by telephone US a week after the leak likely started. Since the event, we now receive realistic volume based alarms as well as daily volume reports from cig. The alarm values will likely be set seasonally going forward.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Corrosion Failure
Cause Details
External Corrosion
Internal External
External Corrosion
Visual Exam Results
Localized Pitting
Galvanic Corrosion Ind
Yes
Field Exam Basis Ind
Yes
Underground Location
Yes
Under Cathodic Protection Ind
Yes
Cathodic Pro Start Year
1975
Shielding Evident
Yes
Cathodic Survey Type
Yes
Cp Annual Survey Ind
Yes
Cp Annual Survey Year
2022
Prior Damage
Yes
Coating Type
Cold Applied Tape
Field Applied Ind
Yes
Cor Hydrotest Leak Survey Date
2022-05-11 00:00:00
Cor Hydrotest Conducted Ind
No
Extrnl Cor Galvanic Ind
Yes
Preparer Name
J*** S****
Preparer Title
Operations And Compliance Manager
Preparer Email
J***@p*******.group
Preparer Telephone
7202272026
Local Contact Name
G***** C****
Local Contact Email
G*****@w********.com
Local Contact Telephone
9703818557
Authorizer Name
J*** S****
Authorizer Title
Operations And Compliance Manager
Authorizer Telephone
7202272026
Authorizer Email
J***@p*******.group
Narrative
On august 31, 2022 the walden pipeline operators received phone calls from the cig control center, about concerns for increased gas usage. Online flow records showed an apparent 10x flow increase around august 23. Cig had checked its delivery meter and found nothing abnormal. The 50-mile transmission system was systematically isolated and checked by section, and cig noted an abrupt drop in flow. The last section isolated was the high-pressure distribution system in colorado that feeds the town systems in cowdrey and walden.Next day we pinpointed low pressure on the 2-inch section that helps feed walden. This was the original supply line to walden, built ca 1958 of coated steel 2" pipe. We had found and fixed a corrosion pinhole leak on this segment earlier in july, the only leak found in 20+ years on any pipeline in colorado. This 17,000 ft segment was looped ca 1979 with a 3" coated steel line, parallel and about 10 ft southeast. The 2" section was isolated and quickly pressured down. Later, gas was reintroduced and a leak survey done in the area around the previous leak. The newer leak was detected about 180 ft sw of the previous repair, running along a shallow sagebrush wash. With this segment shut down and the 3" loop carrying the load, we excavated the new leak area on november 2, intending a repair. The pipe and coating looked identical to that with the nearby leak repair, but was very shallow. The excavated material was mostly black, smelly leak dirt indicative of a long-term gas leak. The excavator stripped out the pipe for 60 ft, and we introduced a small amount of gas from the nearby block valve. The exposed & cleaned-off pipeline didn't leak. But the gas detector picked up gas near the front and north side of the backhoe, well away from the exposed 2" and the side away from the 3" loop. After further investigation, digging out more leak dirt, we eventually found a second string of 2" pipe running parallel to the exposed line, about 7 ft nw and 3.5 ft deeper. We stripped out a 10-ft section of this newly-discovered pipe. The coating was a cold-applied yellow tape with thick black mastic, likely hand-applied with good overlaps and no wrinkles. We could find no obvious defects or holes, until gas was introduced. In less than 5 seconds, the short section appeared to leak in at least 4 places, including a pinkie-size hole in the tape and the pipe on the bottom. Although the tape looked good on first inspection, there were several deep marks and dents, although the soil was rock-free, moist clay. The deep dents may have been made during installation, when the pipe was lowered in with log chains instead of softer pipe slings. This 3rd line is not shown on any maps or described in any documents conveyed from the original owner rocky mountain natural gas to the town in 1995. With 5 corrosion leaks (despite good cp readings) in 200 ft in a few months; and with little hydraulic value, we decided to permanently abandon the 2-inch segment. We cut out an 8-ft section of the leaking pipe, and weld-capped both ends of the 17,000 ft segment, with documentation that this section can't be used again. This leak was about 1.2 miles from the edge of walden. The nearest public road is the county rodeo & fairgrounds about 1/2 mile away, and 0.9 mile to the nearest residence. We believe this leak has persisted for decades. It was not reported by the public, since it is very remote and the prevailing wind generally blows from the southwest, away from any residences or roads. The utility had leak-surveyed the 2 known parallel lines as required by DOT part 192. The vehicle-mounted rig was always driven between the 2 pipelines that are only 8 ft apart. The unknown line was about 12 ft outside the leak survey path. We believe old undetected pinhole leaks blew out with the re-pressurization after the previous repair. No injuries or deaths resulted from this leak. The only damage was the value of lost gas.
| Occurred At | 2022-09-02 05:30:00 |
|---|---|
| Year | 2022 |
| Report Received Date | 2022-11-03 00:00:00 |
| Iyear | 2022.0 |
| Report Number | 20220070.0 |
| Supplemental Number | 37834.0 |
| Report Type | Supplemental Final |
| Operator Id | 30839 PHMSA Enforcement |
| Name | Walden, Town Of |
| Operator Street Address | Po Box 489 513 Harrison St |
| Operator City Name | Walden |
| Operator State Abbreviation | CO |
| Operator Postal Code | 80480 |
| Local Datetime | 2022-08-31 13:00:00 |
| Time Zone | Mountain |
| Daylight Savings Ind | Yes |
| Location Street Address | 0.5 Miles East Of Fair Grounds |
| Location City Name | Walden |
| Location County Name | Jackson |
| Location State Abbreviation | CO |
| Location Postal Code | 80480 |
| Location Latitude | 40.746952 Google Maps OpenStreetMap |
| Location Longitude | -106.2604 Google Maps OpenStreetMap |
| Flow Cont Key Crit Ind | Yes |
| Nrc Rpt Datetime | 2022-10-25 13:38:00 |
| Nrc Rpt Num | 1350815 NRC Report How to search |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 6100.0 |
| Intentional Release | 0.0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Ignite Ind | No |
| Num Pub Evacuated | 0.0 |
| Incident Identified Datetime | 2022-09-02 05:30:00 |
| Communication State Fed Ind | No |
| On Site Datetime | 2022-09-02 09:00:00 |
| Federal | No |
| Location Type | Private Property |
| Incident Area Type | Underground |
| Incident Area Subtype | Under Soil |
| Depth Of Cover | 60.0 |
| Other Underground Facilities | No |
| Crossing | No |
| Pipe Facility Type | Municipally Owned |
| System Part Involved | Main |
| Installation Year | 1970.0 |
| Pipe Diameter | 2.0 |
| Pipe Specification | Unknown |
| Pipe Manufacturer | Unknown |
| Material Involved | Steel |
| Steel Seam Type | Longitudinal Erw - Unknown Frequency |
| Release Type | Leak |
| Leak Type | Pinhole |
| Class Location Type | Class 1 Location |
| Est Cost Oper Paid | 0.0 |
| Est Cost Prop Damage | 2000.0 |
| Est Cost Emergency | 0.0 |
| Est Cost Other | 0.0 |
| Gas Cost In Mcf | 5.3514 |
| Est Cost Unintentional Release | 32644.0 |
| Est Cost Intentional Release | 0.0 |
| Prpty | 34644.0 |
| Commercial Affected | 0.0 |
| Industrial Affected | 0.0 |
| Residences Affected | 0.0 |
| Num Persons Hosp Not Ovnght | 0.0 |
| Num Injured Treated By Emt | 0.0 |
| Num Resident Building Affctd | 0.0 |
| Num Business Building Affctd | 0.0 |
| Accident Psig | 250.0 |
| Normal Psig | 15.0 |
| Mop Psig | 275.0 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Maop Established Date | 1995-04-15 00:00:00 |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Gas Odorized System Type | By-Pass |
| Gas Odorized Lvl Not Msrd Ind | Yes |
| 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 | 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 | The scada system is operated by the gas supplier (colorado interstate gas). They did not have reasonable alarms set for our system and notified by telephone US a week after the leak likely started. Since the event, we now receive realistic volume based alarms as well as daily volume reports from cig. The alarm values will likely be set seasonally going forward. |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Corrosion Failure |
| Cause Details | External Corrosion |
| Internal External | External Corrosion |
| Visual Exam Results | Localized Pitting |
| Galvanic Corrosion Ind | Yes |
| Field Exam Basis Ind | Yes |
| Underground Location | Yes |
| Under Cathodic Protection Ind | Yes |
| Cathodic Pro Start Year | 1975 |
| Shielding Evident | Yes |
| Cathodic Survey Type | Yes |
| Cp Annual Survey Ind | Yes |
| Cp Annual Survey Year | 2022 |
| Prior Damage | Yes |
| Coating Type | Cold Applied Tape |
| Field Applied Ind | Yes |
| Cor Hydrotest Leak Survey Date | 2022-05-11 00:00:00 |
| Cor Hydrotest Conducted Ind | No |
| Extrnl Cor Galvanic Ind | Yes |
| Preparer Name | J*** S**** |
| Preparer Title | Operations And Compliance Manager |
| Preparer Email | J***@p*******.group |
| Preparer Telephone | 7202272026 |
| Local Contact Name | G***** C**** |
| Local Contact Email | G*****@w********.com |
| Local Contact Telephone | 9703818557 |
| Authorizer Name | J*** S**** |
| Authorizer Title | Operations And Compliance Manager |
| Authorizer Telephone | 7202272026 |
| Authorizer Email | J***@p*******.group |
| Narrative | On august 31, 2022 the walden pipeline operators received phone calls from the cig control center, about concerns for increased gas usage. Online flow records showed an apparent 10x flow increase around august 23. Cig had checked its delivery meter and found nothing abnormal. The 50-mile transmission system was systematically isolated and checked by section, and cig noted an abrupt drop in flow. The last section isolated was the high-pressure distribution system in colorado that feeds the town systems in cowdrey and walden.Next day we pinpointed low pressure on the 2-inch section that helps feed walden. This was the original supply line to walden, built ca 1958 of coated steel 2" pipe. We had found and fixed a corrosion pinhole leak on this segment earlier in july, the only leak found in 20+ years on any pipeline in colorado. This 17,000 ft segment was looped ca 1979 with a 3" coated steel line, parallel and about 10 ft southeast. The 2" section was isolated and quickly pressured down. Later, gas was reintroduced and a leak survey done in the area around the previous leak. The newer leak was detected about 180 ft sw of the previous repair, running along a shallow sagebrush wash. With this segment shut down and the 3" loop carrying the load, we excavated the new leak area on november 2, intending a repair. The pipe and coating looked identical to that with the nearby leak repair, but was very shallow. The excavated material was mostly black, smelly leak dirt indicative of a long-term gas leak. The excavator stripped out the pipe for 60 ft, and we introduced a small amount of gas from the nearby block valve. The exposed & cleaned-off pipeline didn't leak. But the gas detector picked up gas near the front and north side of the backhoe, well away from the exposed 2" and the side away from the 3" loop. After further investigation, digging out more leak dirt, we eventually found a second string of 2" pipe running parallel to the exposed line, about 7 ft nw and 3.5 ft deeper. We stripped out a 10-ft section of this newly-discovered pipe. The coating was a cold-applied yellow tape with thick black mastic, likely hand-applied with good overlaps and no wrinkles. We could find no obvious defects or holes, until gas was introduced. In less than 5 seconds, the short section appeared to leak in at least 4 places, including a pinkie-size hole in the tape and the pipe on the bottom. Although the tape looked good on first inspection, there were several deep marks and dents, although the soil was rock-free, moist clay. The deep dents may have been made during installation, when the pipe was lowered in with log chains instead of softer pipe slings. This 3rd line is not shown on any maps or described in any documents conveyed from the original owner rocky mountain natural gas to the town in 1995. With 5 corrosion leaks (despite good cp readings) in 200 ft in a few months; and with little hydraulic value, we decided to permanently abandon the 2-inch segment. We cut out an 8-ft section of the leaking pipe, and weld-capped both ends of the 17,000 ft segment, with documentation that this section can't be used again. This leak was about 1.2 miles from the edge of walden. The nearest public road is the county rodeo & fairgrounds about 1/2 mile away, and 0.9 mile to the nearest residence. We believe this leak has persisted for decades. It was not reported by the public, since it is very remote and the prevailing wind generally blows from the southwest, away from any residences or roads. The utility had leak-surveyed the 2 known parallel lines as required by DOT part 192. The vehicle-mounted rig was always driven between the 2 pipelines that are only 8 ft apart. The unknown line was about 12 ft outside the leak survey path. We believe old undetected pinhole leaks blew out with the re-pressurization after the previous repair. No injuries or deaths resulted from this leak. The only damage was the value of lost gas. |
External Resources
PHMSA pipeline safety insights.
Product
Features
Company
All rights reserved. Copyright © by ClearPHMSA