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.
Investigation determined that internal galling has caused the failure rendering the needle valve unusable. The galling was caused by a stainless steel stem acting against a stainless steel seat. This failure mode had been observed before and the…
Failure of a diaphragm is not infrequent, but the seizure of the main nut threads is very rare. The manufacturer claimed this had never occurred before with this type of unit. The broken plunger is likely the result of poor instructions/…
High-pressure fueling hoses should be examined daily for signs of external damage, including corrosion, abrasion, cuts, and kinking. High-use fueling hoses should be replaced every six months.
The combination of the cold water temperature (reducing the fatigue strength of the bolt), and the abnormally high number of cyclical stresses imposed by the imbalance from the hydraulic system check valve failure resulted in the failure of the…
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…
1. The trailer involved in the incident used a frangible burst disk based upon the proprietary metal compound designated as Inconel #600. Random sampling of similar pressure relief devices from the same trailer showed that all of them failed at…
The uncontrolled release of hydrogen occurred as a result of the rupture of the No. 6 hydrogen storage tube’s burst disc. This disc failed in response to being overloaded by mechanical stresses developed as water expanded and formed ice while in…
Recommendation 1 - Overhaul and replace the diaphragms on all cells showing low-purity results. Check on a routine basis the individual cell purity levels to monitor the deterioration of performance of individual cells. Certain…
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.
Electrical…
Hydrogen distribution lines should be designed and carefully inspected to ensure process equipment in the area is correctly and safely installed. Equipment subject to vibration should not be placed in contact with hydrogen lines or with other…
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 (…
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…
Immediate Corrective Actions
The site needs to implement a good Operational and Readiness Inspection procedure. System inspection deficiencies need to be identified, and (if possible) reviewed by a second party before future tests are conducted. This inspection could include…
Although a functional fire protection system would have helped to extinguish the fire, a properly installed hydrogen detection system, coupled with a properly designed ventilation system, could have prevented the incident altogether.
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This incident emphasizes the need for proper gas detection and ventilation systems, as well as fire suppression systems, in laboratories using and storing hydrogen. This is especially true when open flame burners are in close proximity.…
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