Disclaimer: The Lessons Learned Database includes the incidents that were voluntarily submitted. The database is not a comprehensive source for all incidents that have occurred.
The investigation team concluded that hydrogen gas was released through a failed 19-inch diameter gasket and ignited under the roof of the compressor shed where it was partially confined. Some gas escaped from the shed prior to the explosion, but…
Personnel were focused on the AGES system test and results, not the compatibility of the test equipment. The manual valve was needed to successfully test the system, however the fact that this particular valve could not accommodate the full…
An important aspect of the reliability of a valve is the condition of the stem seal which tends to deteriorate with time and wear. Valves used in hydrogen service should be packed with the correct valve packing material and periodically checked…
An investigative communication notes that "mechanical integrity programs at refineries repeatedly emphasize inspection strategies rather then the use of inherently safer design to control the damage mechanisms that ultimately cause major process…
The researcher's failure to pull the fire alarm was an oversight of required facility practice. The alarm should have been triggered in consideration of the potential for greater harm to personnel and facilities.
Hot, reacting ammonia…
It appears that this was an isolated event caused by human error. The lessons learned are: (1) to caution workers to maintain their focus during fuel cell stack assembly, (2) to require verification that all tools and spare parts are accounted…
A hydrogen release of this type is a significant event. The event highlighted a number of procedural contributing factors that will influence the manner in which these fuel cell systems will be serviced in the future. A complicating factor in…
Procedures for safe handling of compressed gas cylinders, marking design of gas cylinders and connecting lines, and arrangement of cylinders were reviewed and modified as necessary. The spectrometer was returned to the manufacturer for a careful…
In addition to the probable causes listed above, the lack of a standard operating procedure for hydrogen leak detection was one of the probable causes of this incident. Additional contributing factors included the following:
- Severe pipe…
The investigation determined that hydrogen was formed by the reaction of hot aluminum and water, air was admitted via the inspection door, and the mixture was ignited by the hot clinker or sparks from the chisel. Aluminum should have been…
The ignition of the fireball could have been caused by any of the following mechanisms:
Mechanical pressure gauges tend to be imprecise if only used in a narrow portion of the full scale. Digital transducers, although slightly more expensive, offer much more precision. The event happened because the set pressure was only 10% of full…
Corrective actions included replacing the breakaway with a new one, which restored normal operation of the dispenser.
Verify and periodically inspect the pull/separation force adjustment if the breakaway is so equipped.
Additional…
A gas detector was added in close proximity to the compressor shaft and a vibration switch is under consideration. Additional predictive measures are being considered to predict bearing failure. In addition, the manufacturer has been contacted…
Because the bottle was located outside at the time of the event, and the hydrogen did not find a source of ignition while venting through the relief valve, nothing serious happened. The failed regulator was replaced and operations continued.…
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