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.
These events show the importance of preventing combustible gas mixtures from accumulating in piping. In both of the above described events, hydrogen and oxygen gases apparently accumulated to a combustible level which then catastrophically failed…
In the future, refining, petrochemical, and chemical industries need to review material verification programs to ensure that the maintenance procedures include sufficient controls and positive material identification (PMI) testing to prevent…
The accident proves that under special circumstances, the potential hazard connected with unforeseen microbial gas formation and accumulation should not be neglected. Thus, to avoid new accidents at the paper mill described above, the tower has…
The lessons of this event fall into five categories: (1) proper in-plant communications during events, (2) proper valve application for use with hydrogen, (3) excess flow check valve set point, (4) heating and ventilation and air conditioning (…
The investigative report noted that the explosion could have been prevented by (among other things) a continuous gas analyzer test of oxygen and hydrogen product purity. The continuous analyzer should be interlocked to shut the electrolyzer down…
The lesson to pass on is that ventilation is critical in UPS battery rooms. Great care should be taken to ensure that the ventilation system is operational and brings in enough outdoor air to properly ventilate the enclosure.
This incident illustrates the danger of hydrogen being inadvertently released through blown water seals. Similar incidents have occurred in non-nuclear industrial facilities, but offgas systems present a special hazard because of the…
The mechanisms and rates by which hydrogen gas is generated and subsequently accumulated in the holding tank need to be fully understood by vendors and employees alike. Active venting, warning signs, and local alarms designed to activate when…
The above described events are an indication of a potential licensee/vendor interface problem. Based on the information received, the vendor was not completely informed via the purchase specifications regarding the service condition to which the…
The hydrogen facility does not meet industrial guidelines for facilities of this type, from the standpoint of (1) the separation distance needed between a hydrogen pipe break and the building ventilation intake to prevent buildup of a flammable…
This incident illustrates how difficult it is to completely purge hydrogen out of a large, complex piece of equipment. Uniform mixing and dilution is unlikely in all the partially enclosed spaces, crevices, etc. If a hazardous operation such as…
An important lesson to be derived from this incident is the need to carefully engineer and test all repairs and modifications to high-pressure process equipment.
This incident illustrates how a hydrogen fire which appears to be 'quite small' can actually be only the visible portion of a much larger fire. Observation alone is not a reliable technique for detecting pure hydrogen fires and/or…
As demonstrated by the fire discussed above, lack of adequate maintenance, system monitoring and oversight of maintenance of these facilities can contribute to the ignition of a fire that is difficult to extinguish and poses an extreme danger to…
In any event, the lesson that should be derived from this incident is the fact that the explosion could have been avoided either by using an inert gas instead of air across the diaphragm, or by monitoring the hydrogen concentration in the upper…
The recommended safe storage time for AHF is two years. Contact the vendor for pick up and disposal for cylinders more than two years old. (Unused gas should also be returned, even if it has been less than two years…
Test safety system components even if they are new.
Do not rely on listening for valve movement as confirmation that a valve is closing; measure downstream pressure to determine if the valve is really sealing properly.
Utilize a Six Sigma Black Belt to statistically evaluate LFL monitor reliability and determine the failure rate based on the existing technology.
Revise the tank uncertainty calculation and surveillance to include a wider "Required…
The lessons learned in this situation center around basic conduct of operations principles. Policies and procedures related to operations performance, safety performance, and management oversight were in place. They were not employed…
On-site personnel performing treatment of reactive metals/chemicals must continue to exercise caution. Although there is an inherent risk in treating reactive metals/chemicals, personnel must adhere to conduct of operations principles to include…
- = No Ignition
- = Explosion
- = Fire
|Equipment / Cause
|Equipment Design or Selection
|Installation or Maintenance
|Inadequate Gas or Flame Detection
|Emergency Shutdown Response
|Other or Unknown
|Hydrogen Gas Metal Cylinder or Regulator
|Liquid Hydrogen Tank or Delivery Truck
|Pressure Relief Device
|Hydrogen Generation Equipment
|Vehicle or Lift Truck
|Fuel Cell Stack
|Hydrogen Cooled Generator
|Other (floor drain, lab
- = No Ignition
- = Explosion
- = Fire