Description of Incident
A technician identified flashing/arcing on heat tracing tape, attached to a process line, close to where they were working.
The Supervisor requested the heat tracing be isolated. When Electrical personnel went to formally isolate the circuit the residual current breaker (RCB) had already tripped as intended.
The heat tracing tape had not been covered by pipe insulation for a period of time meaning that it had been exposed to the elements and free to move. The tape eventually became damaged by fretting. This then led to the tape arcing, which is an ignition source in a hydrocarbon process area.
The investigation could not determine when the pipe insulation had been removed or by whom – there were no records found for the pipe insulation removal, leading the investigation team to believe it was removed by unauthorised personnel.
Good Practice Guidance
- Pipe insulation must only be removed or reinstated by authorised personnel – if you need to carry out a task and it is covered by pipe insulation, do not just remove it yourself.
- When authorised personnel remove pipe insulation, the heat trace tape will also be isolated.
- If pipe insulation is found to have been removed, raise an Observation Card to ensure it is replaced and check the isolation status of any exposed trace heat tape.