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…

For the use of mechanical fittings in hydrogen service, administrative controls should be in place, as in this case, to ensure that leak testing is conducted on a regular basis. It should never be assumed that every fitting is tight. Additional…

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…

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…

The fitting was an SAE straight thread and was likely loosened by torque applied to the fueling hose. After the incident, these fittings had additional means applied to restrict loosening, a cover installed to deflect any leakage, and means taken…

1. Redundant safety systems prevented this event from becoming an incident. The 1%-hydrogen-concentration-level-triggered fan was backed up by a 2%-hydrogen-concentration alarm. The alarm is continuously monitored (24/7) by a remote Network…

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.…

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 following corrective actions have been taken:

• The non-return valve was dismantled, cleaned, and tested. Following positive testing, the system was restarted and pressurized without any further malfunctioning.
• The hydrogen…

1. All samples with potential for hydrogen buildup should be limited to ground shipment only. (This shipment was by ground and air. If this incident were to have happened in an airplane, the consequences may have been worse.)

2. All samples…

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…

Now, when conducting a sulfur deprivation test, vessels are ventilated to prevent over pressurization and safely facilitate the release of excess hydrogen.

• One needs to take extreme care with both new and supposedly spent hydride samples; the spent materials may contain pockets of unoxidized alanates that could react violently when being transferred.
• Work with small samples so if…

• Valve packing on ammonia tanks should be checked on a regular basis.
• If an ammonia smell becomes noticeable, the tank should be returned to the supplier.

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 (…

Lessons Learned
Construction errors are difficult to detect once construction is complete. It is important to develop and use a systematic oversight process for minimizing construction errors during the construction process.

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• A redundant safety circuit was put into service and the tank returned to normal operation after the failure. Both rupture discs were replaced and the tank was inspected.
• Important to note that the safety system functioned as…

No Lessons Learned, Specific Suggestions for Avoidance, or Mitigation Steps Taken.

• Unprotected hoses are susceptible to glass shards, abrasion, and burns during normal use. This leak was formed from a glass shard penetrating the tube wall.
• Flexible hoses require protective sheaves to avoid cuts, abrasions and…

This occurrence underscores the importance of completing a hazard analysis for each different process. Non-safety-related systems or equipment may be used for purposes other than their primary purpose so long as potential hazards are identified…