Severity
Near-Miss
Leak
Yes
Ignition
No

The hydrogen sensor at a hydrogen fueling station detected a slight leakage from the ground packing of the flow control valve during refueling. The refueling operation was stopped immediately. The leak was stopped by tightening the ground packing sealing screw, but it started leaking again in about a week.

The flow control valve was disassembled and inspected. Dust was found at the ground seal and the packing was distorted. Leakage was believed to be due to the dust invasion and repeated tightening of the sealing screw. The packing had been used for four years and two months without replacement.

Incident Date
May 01, 2007
Setting
Equipment
  • Piping/Fittings/Valves
  • Valve
Damage and Injuries
Probable Cause
Contributing Factors
Characteristics
Lessons Learned

The packing in the flow control valve should be replaced periodically. A planned investigation will determine the optimum time period for packing replacement.