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…

Facilities should review their process systems to determine if they have valves installed that may be subject to this hazard. If so, facilities should conduct a detailed hazard analysis to determine the risk of valve failure. Detailed internal…

1. Test safety system components even if they are new.
2. 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.
3. …

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…

• Battery power supplies require adequate ventilation for all operations, or the battery box should be designed to:
  • Eliminate all sparking devices
  • Ventilate during charging operations
  • Provide inert gas…

Immediate Corrective Actions

1. Fuel cell test stand was shutdown and sent to manufacturer for investigation.
2. Carbon dioxide fire extinguisher installed in laboratory.
3. Formal process hazard review performed…

• A SOP should be developed which prohibits drivers from backing into the fill position.
• As a precautionary measure to mitigate similar events in the future, piping barriers should be installed which protect critical H₂…

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…

• Facilities housing battery charging systems need to ensure the ventilation systems are operational, and delivering enough outdoor air to properly ventilate the enclosure.
• Operators need to be aware of safe practices and proper…

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.

…

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.…

• 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…

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.

• Carefully revise the risk assessment process to evaluate any confined areas where hydrogen is handled.
• Separate the fire and gas detection alarm system from the process information to provide easy and clear identification.…

1. Carbon steel Nelson curve methodology cannot be depended on to prevent HTHA equipment failures and cannot be reliably used to predict the occurrence of HTHA equipment damage. Revisions to recommended practices should be considered…