Incident details
Operator, cause, commodity and consequences with raw source fields.
GD incident on 2018-08-26 — MT
Operator
Energy West Montana
Cause
Pipe, Weld, Or Joint Failure
Commodity
Natural Gas
Program
GD
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$900
Incident datetime
2018-08-26 06:27
Report number
Location
MT, CASCADE
Narrative
The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were directly under the footing and foundation of 4601 willowdale lane. There appeared to be external damage to the 1" coupling and the 1" cts piping appears to have been lowered in place by the home builder. The 1" cts piping was a dead end service stub and was unknowingly operating at 230 psi due to a previous uprate of a 10" steel pipeline. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were subject to a shockwave created by the home explosion. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling is being sent to an independent lab for a forensic investigation and testing. 4/12/2019: lab testing results were received from two third party consultants. Results indicated that the 1" coupling failed due to slow crack growth propagation as a result of multiple stresses being applied to the fitting. Per the reports, the crack growth and leak point on the coupling was consistent with a tensile load on the coupling. The phenomena of a brittle crack which starts in the location where the heat fusion joined tubing terminates on the interior of a socket fusion has been documented previously in industry. The crack formed by the notch geometry created by the inserted tubing and its point of heat fusion joining to the socket which, when under gas pressure, can create a stress riser. The notch geometry may have been contributed by the socket fusion tools available at the time of installation. The failure is also consistent with industry knowledge of aldyl-a pipe and fittings manufactured prior to 1984 and susceptibility to inner wall cracking. The coupling was 10" under the foundation of the garage and appeared to be lowered in place during the construction of the structure. Lowering would have caused tensile stress on the pipe and coupling. No external damages were seen on the pipe or coupling from construction of the garage structure. Again per the reports, the internal pressure in the pipe may have accelerated the failure in the coupling but could not be determined as the sole root cause of the failure. The time to failure from cracking could not be estimated or determined in either report. 11/19/2019 - submitted as final report without further changes at this time.
Detailed record list
Occurred At
2018-08-26 06:27:00
Year
2018
Report Received Date
2018-09-13 00:00:00
Iyear
2018.0
Report Number
20180084.0
Supplemental Number
33027.0
Report Type
Supplemental Final
Operator Id
31191
Name
Energy West Montana
Operator Street Address
No. 1 First Avenue South P.o. Box 2229
Operator City Name
Great Falls
Operator State Abbreviation
MT
Operator Postal Code
59403-2229
Local Datetime
2018-08-26 03:39:00
Location Street Address
4601 Willowdale Lane
Location City Name
Great Falls
Location County Name
Cascade
Location State Abbreviation
MT
Location Postal Code
59404
Location Latitude
47.46361
Location Longitude
-111.31722
Nrc Rpt Datetime
2018-08-26 13:52:00
Nrc Rpt Num
1222758
Commodity Released Type
Natural Gas
Unintentional Release
0.1
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Ignite Ind
Yes
Explode Ind
Yes
Num Pub Evacuated
2.0
Incident Identified Datetime
2018-08-26 06:27:00
On Site Datetime
2018-08-26 03:55:00
Federal
No
Location Type
Private Property
Incident Area Type
Underground
Incident Area Subtype
Under A Building
Depth Of Cover
60.0
Crossing
No
Pipe Facility Type
Privately Owned
System Part Involved
Service
Installation Year
1980.0
Pipe Diameter
1.0
Pipe Specification
Astm D2513
Pipe Manufacturer
Dupont
Material Involved
Plastic
Plastic Type
Polyethylene (Pe)
Plastic Sdr
11.5
Material Pe Pipe Code
2306
Release Type
Leak
Leak Type
Connection Failure
Class Location Type
Class 3 Location
Est Cost Oper Paid
700000.0
Est Cost Prop Damage
900.0
Est Cost Emergency
7100.0
Est Cost Other
0.0
Est Cost Unintentional Release
0.0
Prpty
708000.0
Commercial Affected
0.0
Industrial Affected
0.0
Residences Affected
2.0
Accident Psig
230.0
Normal Psig
60.0
Mop Psig
60.0
Accident Pressure
Pressure Exceeded The Applicable Allowance In 192.201
Scada In Place Ind
No
Accident Identifier
Notification From Emergency Responder
Investigation Status
No, the facility was not monitored by a controller(s) at the time of the incident
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Pipe, Weld, Or Joint Failure
Cause Details
Fusion Joint
Pwjf Failure Type
Fusion Joint
Plastic Joint Subtype
Socket, Heat Fusion
Fpw Installed Year
1980
Fpw Other Attr
Aldyl-A
Fpw First Plastic Type
Polyethylene (Pe)
Fpw Second Plastic Type
Polyethylene (Pe)
Additional Other Ind
Yes
Additional Factor Details
Tensile Stress, & External And Internal Pressure
Result Previous Ind
Yes
Hydrotest Conducted Ind
No
Preparer Name
I** S******
Preparer Title
Safety Director
Preparer Email
I*******@e***.net
Preparer Telephone
4068680748
Authorizer Name
I** S******
Authorizer Title
Safety Director
Authorizer Telephone
4068680748
Authorizer Email
I*******@e***.net
Narrative
The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were directly under the footing and foundation of 4601 willowdale lane. There appeared to be external damage to the 1" coupling and the 1" cts piping appears to have been lowered in place by the home builder. The 1" cts piping was a dead end service stub and was unknowingly operating at 230 psi due to a previous uprate of a 10" steel pipeline. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were subject to a shockwave created by the home explosion. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling is being sent to an independent lab for a forensic investigation and testing. 4/12/2019: lab testing results were received from two third party consultants. Results indicated that the 1" coupling failed due to slow crack growth propagation as a result of multiple stresses being applied to the fitting. Per the reports, the crack growth and leak point on the coupling was consistent with a tensile load on the coupling. The phenomena of a brittle crack which starts in the location where the heat fusion joined tubing terminates on the interior of a socket fusion has been documented previously in industry. The crack formed by the notch geometry created by the inserted tubing and its point of heat fusion joining to the socket which, when under gas pressure, can create a stress riser. The notch geometry may have been contributed by the socket fusion tools available at the time of installation. The failure is also consistent with industry knowledge of aldyl-a pipe and fittings manufactured prior to 1984 and susceptibility to inner wall cracking. The coupling was 10" under the foundation of the garage and appeared to be lowered in place during the construction of the structure. Lowering would have caused tensile stress on the pipe and coupling. No external damages were seen on the pipe or coupling from construction of the garage structure. Again per the reports, the internal pressure in the pipe may have accelerated the failure in the coupling but could not be determined as the sole root cause of the failure. The time to failure from cracking could not be estimated or determined in either report. 11/19/2019 - submitted as final report without further changes at this time.
| Occurred At | 2018-08-26 06:27:00 |
|---|---|
| Year | 2018 |
| Report Received Date | 2018-09-13 00:00:00 |
| Iyear | 2018.0 |
| Report Number | 20180084.0 |
| Supplemental Number | 33027.0 |
| Report Type | Supplemental Final |
| Operator Id | 31191 PHMSA Enforcement |
| Name | Energy West Montana |
| Operator Street Address | No. 1 First Avenue South P.o. Box 2229 |
| Operator City Name | Great Falls |
| Operator State Abbreviation | MT |
| Operator Postal Code | 59403-2229 |
| Local Datetime | 2018-08-26 03:39:00 |
| Location Street Address | 4601 Willowdale Lane |
| Location City Name | Great Falls |
| Location County Name | Cascade |
| Location State Abbreviation | MT |
| Location Postal Code | 59404 |
| Location Latitude | 47.46361 Google Maps OpenStreetMap |
| Location Longitude | -111.31722 Google Maps OpenStreetMap |
| Nrc Rpt Datetime | 2018-08-26 13:52:00 |
| Nrc Rpt Num | 1222758 NRC Report How to search |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 0.1 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Ignite Ind | Yes |
| Explode Ind | Yes |
| Num Pub Evacuated | 2.0 |
| Incident Identified Datetime | 2018-08-26 06:27:00 |
| On Site Datetime | 2018-08-26 03:55:00 |
| Federal | No |
| Location Type | Private Property |
| Incident Area Type | Underground |
| Incident Area Subtype | Under A Building |
| Depth Of Cover | 60.0 |
| Crossing | No |
| Pipe Facility Type | Privately Owned |
| System Part Involved | Service |
| Installation Year | 1980.0 |
| Pipe Diameter | 1.0 |
| Pipe Specification | Astm D2513 |
| Pipe Manufacturer | Dupont |
| Material Involved | Plastic |
| Plastic Type | Polyethylene (Pe) |
| Plastic Sdr | 11.5 |
| Material Pe Pipe Code | 2306 |
| Release Type | Leak |
| Leak Type | Connection Failure |
| Class Location Type | Class 3 Location |
| Est Cost Oper Paid | 700000.0 |
| Est Cost Prop Damage | 900.0 |
| Est Cost Emergency | 7100.0 |
| Est Cost Other | 0.0 |
| Est Cost Unintentional Release | 0.0 |
| Prpty | 708000.0 |
| Commercial Affected | 0.0 |
| Industrial Affected | 0.0 |
| Residences Affected | 2.0 |
| Accident Psig | 230.0 |
| Normal Psig | 60.0 |
| Mop Psig | 60.0 |
| Accident Pressure | Pressure Exceeded The Applicable Allowance In 192.201 |
| Scada In Place Ind | No |
| Accident Identifier | Notification From Emergency Responder |
| Investigation Status | No, the facility was not monitored by a controller(s) at the time of the incident |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Pipe, Weld, Or Joint Failure |
| Cause Details | Fusion Joint |
| Pwjf Failure Type | Fusion Joint |
| Plastic Joint Subtype | Socket, Heat Fusion |
| Fpw Installed Year | 1980 |
| Fpw Other Attr | Aldyl-A |
| Fpw First Plastic Type | Polyethylene (Pe) |
| Fpw Second Plastic Type | Polyethylene (Pe) |
| Additional Other Ind | Yes |
| Additional Factor Details | Tensile Stress, & External And Internal Pressure |
| Result Previous Ind | Yes |
| Hydrotest Conducted Ind | No |
| Preparer Name | I** S****** |
| Preparer Title | Safety Director |
| Preparer Email | I*******@e***.net |
| Preparer Telephone | 4068680748 |
| Authorizer Name | I** S****** |
| Authorizer Title | Safety Director |
| Authorizer Telephone | 4068680748 |
| Authorizer Email | I*******@e***.net |
| Narrative | The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were directly under the footing and foundation of 4601 willowdale lane. There appeared to be external damage to the 1" coupling and the 1" cts piping appears to have been lowered in place by the home builder. The 1" cts piping was a dead end service stub and was unknowingly operating at 230 psi due to a previous uprate of a 10" steel pipeline. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling were subject to a shockwave created by the home explosion. The 1" cts, sdr 11.5, aldyl-a pipe and 1" socket fusion coupling is being sent to an independent lab for a forensic investigation and testing. 4/12/2019: lab testing results were received from two third party consultants. Results indicated that the 1" coupling failed due to slow crack growth propagation as a result of multiple stresses being applied to the fitting. Per the reports, the crack growth and leak point on the coupling was consistent with a tensile load on the coupling. The phenomena of a brittle crack which starts in the location where the heat fusion joined tubing terminates on the interior of a socket fusion has been documented previously in industry. The crack formed by the notch geometry created by the inserted tubing and its point of heat fusion joining to the socket which, when under gas pressure, can create a stress riser. The notch geometry may have been contributed by the socket fusion tools available at the time of installation. The failure is also consistent with industry knowledge of aldyl-a pipe and fittings manufactured prior to 1984 and susceptibility to inner wall cracking. The coupling was 10" under the foundation of the garage and appeared to be lowered in place during the construction of the structure. Lowering would have caused tensile stress on the pipe and coupling. No external damages were seen on the pipe or coupling from construction of the garage structure. Again per the reports, the internal pressure in the pipe may have accelerated the failure in the coupling but could not be determined as the sole root cause of the failure. The time to failure from cracking could not be estimated or determined in either report. 11/19/2019 - submitted as final report without further changes at this time. |
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