Fire on a hydrogen pipe of a refinery

This incident occurred at a refinery, on a pipe transporting hydrogen at 24 bar placed at 6 m above ground. A 15 cm long hydrogen flame was detected at an anti-leak system temporarily installed on the pipe to prevent a leak on a damaged valve. This temporary system had been installed a year earlier, to allow continuation of the operation, avoiding the need of a shut-down of the whole unit.
The crisis unit and the emergency plan were activated. Internal response teams set up a safety perimeter. Units were put on standby to isolate and decompress the section. The leak was stopped after 3 hours.
The excess hydrogen produced by the unit was sent to the flare network pending repairs. Leak tests were performed on the isolation valves of the line section. The temporary system was removed, and the leaking valve, which was not required for operation, was removed. The emergency plan 8 hours after the start of the emergency.

valve, pipe

The temporary system had been installed a year earlier. This so-called “leak-in-operating” device is a temporary device installed on a leak in an industrial facility, such as a pipe or valve, to allow for a safer repair, often avoiding a shutdown of the facility.
These systems are subject to strict procedures, including risk analysis and equipment monitoring, and must be replaced with a permanent repair during the first scheduled shutdown, or at the latest by the regulatory deadline.

The event description is mainly based on local news information, and lack of the required technical details to extract a specific lesson learnt.
The consequences have been rather limited, the emergency actions were effective, nobody was injured and there was no impact outside the fence.
Nevertheless, it is still possible to formulate the following reflection:
(1) At the origin of the series of event there was a leaking. A temporary leak-in-operating had been installed to avoid the immediate shut-down of the industrial process.
(2) The incident occurred a year after the device had been installed.
(3) The leak-in-operating solution is a temporary solution, which must be replaced with a permanent repair during the first scheduled shutdown.
(4) Clearly, the design and/or the installation of this device was not enough to guarantee leak-free operation for such a long time.