Manuals showing the correct connecting and disconnecting procedures were established for each fueling dispenser. Separate manuals were needed since the shape of the grip differs from dispenser to dispenser.

1. Provide additional retraining of operators. Curriculum should emphasize the proper response to high oxygen in the hydrogen gas.
2. Evaluate current knowledge of operators. Operators should know…

A step was added to the laboratory procedure in which all catalyst waste is thoroughly dampened with water and sealed in a plastic bag before being placed into a waste container.

Safe work procedures will be prepared and followed. Hydrogen will be vented out of the system to create an inert atmosphere before working on system tubing and joints. The importance of purging hydrogen piping and equipment is discussed in the…

1. Maintenance work scopes must be adhered to. If added work is approved, it must be tracked and reviewed to ensure that the equipment is inspected by operations personnel. Scheduled work and extra work should be listed and checked off for…

Disable the fueling process if the operator does not follow the proper sequence of steps in the fueling procedure. Improve the fueling procedure to make it inherently impossible for the sequence to be done improperly with the same result.

Shutoff valve location and/or redundant shutoff valves at storage vessels are important for containment to prevent escalation.
Consider design features within equipment skids to reduce the likelihood of cascading events.
Pressure-switch…

Lessons Learned The site initiated the establishment of a field patrol and strengthened their onsite monitoring of mechanical equipment during a plant-wide temperature rise.

• Quantitative control of tightening torque on bolts…

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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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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Routine maintenance activities on pressurized hydrogen systems should be conducted per written design specifications. The procedures should provide detailed oversight regarding bolt, nut and fitting replacements or repairs. A formal review…

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.…

Hazards should be eliminated to the extent possible rather than depending on workers to follow an operations manual.

Potassium carbonate draw-off operations should be improved, and the operations manual should be revised. The manual…

Fail-safe position of control valves in supply lines must be set correctly to prevent damage to pressure vessels.

Recommendation

Set all valves for fail safe operation (open or closed) according to needs before installation…

1. The dilution water for making a polythionic acid aqueous solution was changed from industrial water to pure water to lower the chlorine concentration in the piping.
2. Water that accumulated in the drain was removed before heating…

1. The plant tried to increase production and decrease workload, but failed to notice the potential negative outcomes of this change.
2. It is necessary to thoroughly simulate all potential negative outcomes of a change in procedures…

• Operation and management of the hydrodesulfurization unit should be strengthened to account for abnormal phenomena such as local corrosion.
• The safety review system for remodeling existing equipment and facilities should be…

• Verify that all PRDs contain fuse-backed adapters.
• Explore elimination of rupture disk PRDs and substitution of spring-style relief valves.
• Develop new hydrogen unloading procedure using a written checklist. * Add…

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…