Incident details
Operator, cause, commodity and consequences with raw source fields.
GD incident on 2011-10-17 — MI
Operator
Michigan Consolidated Gas Co (Michcon)
Cause
Incorrect Operation
Commodity
Natural Gas
Program
GD
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$0
Incident datetime
2011-10-17 10:15
Report number
Location
MI, KENT
Narrative
On october 17, 2011, beginning at approximately 8:45 am, michcon technicians executed a pressure reduction procedure to facilitate the connection of a newly-constructed regulating station at collindale avenue along michcon's 22-inch south grand rapids 238 psig pipeline. The purpose of the procedure was to dispose of a build-up of natural gas (determined later to have actually been a mixture or air and gas) in the 22-inch pipeline by transferring it at 10 psig into michcon's grand rapids/walker distribution system rather than releasing it to the atmosphere and flaring (burning) the gas. The procedure was executed precisely as written and approved by michcon engineering. At approximately 10:15 am, while the pressure reduction procedure was still in progress, michcon began to receive "no-gas" reports from customers served by the surrounding 10 psig distribution system. At approximately 11:00 am, michcon personnel realized there had been an air and gas mixture in the 22-inch pipeline, rather than gas. Pressure reduction operations were halted immediately. Michcon engineering and operations personnel immediately convened to determine the extent of the affected area and the source of the air/gas mixture. Michcon determined that approximately 5500 customers over an area of about 10 square miles could ultimately be affected. However, between the initial outage reports at 10:15 am and the early afternoon of october 17, there were only about 100 "no-gas" reports. This number grew to approximately 350 outage reports by 8 pm as customers returned home at the end of the day. At 8 pm michcon management declared this a "significant event" and a telephonic report was made to the national response center. Crews were mobilized from michcon regions across the state of michigan to make a door-to-door investigation of every customer premises in the affected area to ensure that gas service was being restored and that all appliances were operating properly. Michcon engineers developed a plan to systematically purge the air/gas mixture from the 10 psig distribution system, and individual service lines were purged of the air/gas mixture wherever it was found. By friday, october 21, 2011, every customer had either been contacted or their premises were entered with the assistance of law enforcement and locksmiths to confirm that gas service had been restored. There were no fires, explosions, or injuries reported as a result of this event. Michcon has determined the formation of the air/gas mixture inside the 2.5-mile section of the 22-inch 238 psig pipeline began almost immediately after the segment was taken out of service during august 2011. The 22-inch pipeline had been shut in between michcon's south grand rapids gate station to the west and the new collindale regulating station on the east end of the 22-inch pipeline segment. The 2.5-mile section of pipeline had been evacuated and purged of gas, then capped off at the collindale regulating station site while construction of the station was completed. A 22-inch block valve at the south grand rapids gate station that was used to isolate the west end of the 2.5-mile section of 22-inch pipeline allowed gas to slowly bleed past the valve seat, mixing with the air left in the purged section of 22-inch pipeline during the period between august and october 2011. The michcon engineer who developed the written procedure for october 17 recognized that the gas bleeding through the 22-inch block valve was creating a pressure build-up, but failed to recognize this would create an air/gas mixture that would be unfit for distribution to customers. Michcon has determined approximately 136,000 cubic feet of an air/gas mixture had accumulated in the 2.5-mile section of 22-inch pipeline. A significant portion of this mixture was introduced into the surrounding 10 psig distribution system during the procedure executed on october 17, 2011, resulting in the customer outages.
Detailed record list
Occurred At
2011-10-17 10:15:00
Year
2011
Report Received Date
2011-11-16 00:00:00
Iyear
2011.0
Report Number
20110381.0
Supplemental Number
15349.0
Report Type
Original Final
Operator Id
12408
Name
Michigan Consolidated Gas Co (Michcon)
Operator Street Address
One Energy Plaza
Operator City Name
Detroit
Operator State Abbreviation
MI
Operator Postal Code
48226
Local Datetime
2011-10-17 10:15:00
Location Street Address
Collindale District Regulating Station
Location City Name
Grand Rapids
Location County Name
Kent
Location State Abbreviation
MI
Location Postal Code
49504
Location Latitude
42.96297
Location Longitude
-85.73494
Nrc Rpt Datetime
2011-10-17 20:13:00
Nrc Rpt Num
992840
Commodity Released Type
Natural Gas
Unintentional Release
0.0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Ignite Ind
No
Explode Ind
No
Num Pub Evacuated
0.0
Incident Identified Datetime
2011-10-17 10:15:00
On Site Datetime
2011-10-17 10:15:00
Federal
No
Location Type
Public Property
Incident Area Type
Underground
Incident Area Subtype
In Underground Enclosed Space (E.g. Vault)
Depth Of Cover
84.0
Crossing
No
Pipe Facility Type
Privately Owned
System Part Involved
District Regulator/metering Station
Installation Year
1971.0
Material Involved
Other
Material Details
Steel,copper,plastic Services And Mains
Release Type
Other
Release Type Details
No Release - This Incident Resulted From The Accidental Introduction Of A Air/gas Mixture Into A Distribution System, Resulting In Service Outages. There Was No Release.
Class Location Type
Class 3 Location
Est Cost Oper Paid
0.0
Est Cost Prop Damage
0.0
Est Cost Emergency
664451.0
Est Cost Other
1356.0
Est Cost Other Details
Customer Appliance Repairs Performed By Dealers Other Than Michcon.
Est Cost Unintentional Release
0.0
Prpty
665807.0
Commercial Affected
70.0
Industrial Affected
0.0
Residences Affected
1300.0
Accident Psig
10.0
Normal Psig
10.0
Mop Psig
10.0
Accident Pressure
Pressure Did Not Exceed Maop
Scada In Place Ind
No
Accident Identifier
Notification From Public
Investigation Status
No, the facility was not monitored by a controller(s) at the time of the incident
Employee Drug Test Ind
Yes
Num Employees Tested
1
Num Employees Failed
0
Contractor Drug Test Ind
No
Cause
Incorrect Operation
Cause Details
Other Incorrect Operation
Operation Type
Other Incorrect Operation
Operation Details
Written Procedure Did Not Recognize An Air/gas Mixture Was In The Pipeline Being Depressurized. Air/gas Mixture Was Introduced Into Distribution System, Causing Outages.
Related Inadequate Proc Ind
Yes
Category Type
Commissioning
Operator Qualification Ind
No
Preparer Name
J*** F K*****
Preparer Title
Regional Codes Consultant
Preparer Email
K******@d********.com
Preparer Telephone
616.632.2744
Preparer Fax
616.632.2687
Authorizer Name
J*** D L****** P*
Authorizer Title
Supervising Engineer
Authorizer Telephone
616.632.2646
Authorizer Email
L*******@d********.com
Narrative
On october 17, 2011, beginning at approximately 8:45 am, michcon technicians executed a pressure reduction procedure to facilitate the connection of a newly-constructed regulating station at collindale avenue along michcon's 22-inch south grand rapids 238 psig pipeline. The purpose of the procedure was to dispose of a build-up of natural gas (determined later to have actually been a mixture or air and gas) in the 22-inch pipeline by transferring it at 10 psig into michcon's grand rapids/walker distribution system rather than releasing it to the atmosphere and flaring (burning) the gas. The procedure was executed precisely as written and approved by michcon engineering. At approximately 10:15 am, while the pressure reduction procedure was still in progress, michcon began to receive "no-gas" reports from customers served by the surrounding 10 psig distribution system. At approximately 11:00 am, michcon personnel realized there had been an air and gas mixture in the 22-inch pipeline, rather than gas. Pressure reduction operations were halted immediately. Michcon engineering and operations personnel immediately convened to determine the extent of the affected area and the source of the air/gas mixture. Michcon determined that approximately 5500 customers over an area of about 10 square miles could ultimately be affected. However, between the initial outage reports at 10:15 am and the early afternoon of october 17, there were only about 100 "no-gas" reports. This number grew to approximately 350 outage reports by 8 pm as customers returned home at the end of the day. At 8 pm michcon management declared this a "significant event" and a telephonic report was made to the national response center. Crews were mobilized from michcon regions across the state of michigan to make a door-to-door investigation of every customer premises in the affected area to ensure that gas service was being restored and that all appliances were operating properly. Michcon engineers developed a plan to systematically purge the air/gas mixture from the 10 psig distribution system, and individual service lines were purged of the air/gas mixture wherever it was found. By friday, october 21, 2011, every customer had either been contacted or their premises were entered with the assistance of law enforcement and locksmiths to confirm that gas service had been restored. There were no fires, explosions, or injuries reported as a result of this event. Michcon has determined the formation of the air/gas mixture inside the 2.5-mile section of the 22-inch 238 psig pipeline began almost immediately after the segment was taken out of service during august 2011. The 22-inch pipeline had been shut in between michcon's south grand rapids gate station to the west and the new collindale regulating station on the east end of the 22-inch pipeline segment. The 2.5-mile section of pipeline had been evacuated and purged of gas, then capped off at the collindale regulating station site while construction of the station was completed. A 22-inch block valve at the south grand rapids gate station that was used to isolate the west end of the 2.5-mile section of 22-inch pipeline allowed gas to slowly bleed past the valve seat, mixing with the air left in the purged section of 22-inch pipeline during the period between august and october 2011. The michcon engineer who developed the written procedure for october 17 recognized that the gas bleeding through the 22-inch block valve was creating a pressure build-up, but failed to recognize this would create an air/gas mixture that would be unfit for distribution to customers. Michcon has determined approximately 136,000 cubic feet of an air/gas mixture had accumulated in the 2.5-mile section of 22-inch pipeline. A significant portion of this mixture was introduced into the surrounding 10 psig distribution system during the procedure executed on october 17, 2011, resulting in the customer outages.
| Occurred At | 2011-10-17 10:15:00 |
|---|---|
| Year | 2011 |
| Report Received Date | 2011-11-16 00:00:00 |
| Iyear | 2011.0 |
| Report Number | 20110381.0 |
| Supplemental Number | 15349.0 |
| Report Type | Original Final |
| Operator Id | 12408 PHMSA Enforcement |
| Name | Michigan Consolidated Gas Co (Michcon) |
| Operator Street Address | One Energy Plaza |
| Operator City Name | Detroit |
| Operator State Abbreviation | MI |
| Operator Postal Code | 48226 |
| Local Datetime | 2011-10-17 10:15:00 |
| Location Street Address | Collindale District Regulating Station |
| Location City Name | Grand Rapids |
| Location County Name | Kent |
| Location State Abbreviation | MI |
| Location Postal Code | 49504 |
| Location Latitude | 42.96297 Google Maps OpenStreetMap |
| Location Longitude | -85.73494 Google Maps OpenStreetMap |
| Nrc Rpt Datetime | 2011-10-17 20:13:00 |
| Nrc Rpt Num | 992840 NRC Report How to search |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 0.0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Ignite Ind | No |
| Explode Ind | No |
| Num Pub Evacuated | 0.0 |
| Incident Identified Datetime | 2011-10-17 10:15:00 |
| On Site Datetime | 2011-10-17 10:15:00 |
| Federal | No |
| Location Type | Public Property |
| Incident Area Type | Underground |
| Incident Area Subtype | In Underground Enclosed Space (E.g. Vault) |
| Depth Of Cover | 84.0 |
| Crossing | No |
| Pipe Facility Type | Privately Owned |
| System Part Involved | District Regulator/metering Station |
| Installation Year | 1971.0 |
| Material Involved | Other |
| Material Details | Steel,copper,plastic Services And Mains |
| Release Type | Other |
| Release Type Details | No Release - This Incident Resulted From The Accidental Introduction Of A Air/gas Mixture Into A Distribution System, Resulting In Service Outages. There Was No Release. |
| Class Location Type | Class 3 Location |
| Est Cost Oper Paid | 0.0 |
| Est Cost Prop Damage | 0.0 |
| Est Cost Emergency | 664451.0 |
| Est Cost Other | 1356.0 |
| Est Cost Other Details | Customer Appliance Repairs Performed By Dealers Other Than Michcon. |
| Est Cost Unintentional Release | 0.0 |
| Prpty | 665807.0 |
| Commercial Affected | 70.0 |
| Industrial Affected | 0.0 |
| Residences Affected | 1300.0 |
| Accident Psig | 10.0 |
| Normal Psig | 10.0 |
| Mop Psig | 10.0 |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Scada In Place Ind | No |
| Accident Identifier | Notification From Public |
| Investigation Status | No, the facility was not monitored by a controller(s) at the time of the incident |
| Employee Drug Test Ind | Yes |
| Num Employees Tested | 1 |
| Num Employees Failed | 0 |
| Contractor Drug Test Ind | No |
| Cause | Incorrect Operation |
| Cause Details | Other Incorrect Operation |
| Operation Type | Other Incorrect Operation |
| Operation Details | Written Procedure Did Not Recognize An Air/gas Mixture Was In The Pipeline Being Depressurized. Air/gas Mixture Was Introduced Into Distribution System, Causing Outages. |
| Related Inadequate Proc Ind | Yes |
| Category Type | Commissioning |
| Operator Qualification Ind | No |
| Preparer Name | J*** F K***** |
| Preparer Title | Regional Codes Consultant |
| Preparer Email | K******@d********.com |
| Preparer Telephone | 616.632.2744 |
| Preparer Fax | 616.632.2687 |
| Authorizer Name | J*** D L****** P* |
| Authorizer Title | Supervising Engineer |
| Authorizer Telephone | 616.632.2646 |
| Authorizer Email | L*******@d********.com |
| Narrative | On october 17, 2011, beginning at approximately 8:45 am, michcon technicians executed a pressure reduction procedure to facilitate the connection of a newly-constructed regulating station at collindale avenue along michcon's 22-inch south grand rapids 238 psig pipeline. The purpose of the procedure was to dispose of a build-up of natural gas (determined later to have actually been a mixture or air and gas) in the 22-inch pipeline by transferring it at 10 psig into michcon's grand rapids/walker distribution system rather than releasing it to the atmosphere and flaring (burning) the gas. The procedure was executed precisely as written and approved by michcon engineering. At approximately 10:15 am, while the pressure reduction procedure was still in progress, michcon began to receive "no-gas" reports from customers served by the surrounding 10 psig distribution system. At approximately 11:00 am, michcon personnel realized there had been an air and gas mixture in the 22-inch pipeline, rather than gas. Pressure reduction operations were halted immediately. Michcon engineering and operations personnel immediately convened to determine the extent of the affected area and the source of the air/gas mixture. Michcon determined that approximately 5500 customers over an area of about 10 square miles could ultimately be affected. However, between the initial outage reports at 10:15 am and the early afternoon of october 17, there were only about 100 "no-gas" reports. This number grew to approximately 350 outage reports by 8 pm as customers returned home at the end of the day. At 8 pm michcon management declared this a "significant event" and a telephonic report was made to the national response center. Crews were mobilized from michcon regions across the state of michigan to make a door-to-door investigation of every customer premises in the affected area to ensure that gas service was being restored and that all appliances were operating properly. Michcon engineers developed a plan to systematically purge the air/gas mixture from the 10 psig distribution system, and individual service lines were purged of the air/gas mixture wherever it was found. By friday, october 21, 2011, every customer had either been contacted or their premises were entered with the assistance of law enforcement and locksmiths to confirm that gas service had been restored. There were no fires, explosions, or injuries reported as a result of this event. Michcon has determined the formation of the air/gas mixture inside the 2.5-mile section of the 22-inch 238 psig pipeline began almost immediately after the segment was taken out of service during august 2011. The 22-inch pipeline had been shut in between michcon's south grand rapids gate station to the west and the new collindale regulating station on the east end of the 22-inch pipeline segment. The 2.5-mile section of pipeline had been evacuated and purged of gas, then capped off at the collindale regulating station site while construction of the station was completed. A 22-inch block valve at the south grand rapids gate station that was used to isolate the west end of the 2.5-mile section of 22-inch pipeline allowed gas to slowly bleed past the valve seat, mixing with the air left in the purged section of 22-inch pipeline during the period between august and october 2011. The michcon engineer who developed the written procedure for october 17 recognized that the gas bleeding through the 22-inch block valve was creating a pressure build-up, but failed to recognize this would create an air/gas mixture that would be unfit for distribution to customers. Michcon has determined approximately 136,000 cubic feet of an air/gas mixture had accumulated in the 2.5-mile section of 22-inch pipeline. A significant portion of this mixture was introduced into the surrounding 10 psig distribution system during the procedure executed on october 17, 2011, resulting in the customer outages. |
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