Fire in a Hydrogen Pipe
A leak occurred on a 4 inch hydrogen main gas line which ran along a pipe bridge at the east end of a first stage compression plant building, ignited.The source of ignition was hot welding sparks arising from work being carried out by contract personnel whilst installing a new chlorine line above the hydrogen main on the pipe-bridge.Before the welding work was carried out, an explosivity test had been carried out in the area and a nil result had been entered on the work permit.An investigation into the incident found that the removed section of the hydrogen main revealed an elliptical hole 2 centimetres x 1 and a half centimetres. It was only when the lagging was disturbed that the hydrogen leak became obvious.
Event Date
October 2, 1979
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
Root cause was clear. The investigation into the incident found an elliptical hole 2 centimeters x 1 and a half centimeters.The area around the hole in hydrogen main was very pitted suggesting that the failure was due to localized corrosion. The leak was not detected during the explosivity test because of a build up of scale sealing the hole, possibly dislodged later by the activities of the contractors in the area.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
Separation equipment
Storage/Process Medium
Location Type
Location description
Industrial Area
Operational Condition
Lessons Learned
Lessons Learned
The area around the hole in hydrogen main was very pitted and suggested that the failure was due to localized corrosion, though the cause was not apparent. Judging from the size of the hole, it is likely that the leak was not detected during the explosivity test because of a build up of scale sealing the hole, which possibly may have become dislodged later by the activities of the contractors in the area.The lagging on the line would make a leak less obvious and it is debatable that a small hydrogen leak in an open air situation on a windy day, may not be picked up by an explosimeter.
Event Nature
Emergency Action
The welder saw the hole appeared as if the lagging on the pipe had caught fire and an unsuccessful attempt was made to put it out using carbon dioxide fire extinguishers and then water.
Release Type
Release Substance
Hole Shape
Hole Length (mm)
2
Hole Width (mm)
1
Ignition Source
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Flame Type
Source Category
References
References
Event description extracted from the UK database ICHEME in PDF.
The ICHEME database is no longer available for purchase, but data can be download as PDF for free.
https://www.icheme.org/knowledge/safety-centre/resources/accident-data/
(accessed October 2020)