Severity
Incident
Leak
Yes
Ignition
Uncertain

The bulkhead between a liquid hydrogen tank and a liquid oxygen tank failed due to a series of events. Air services to the building were shut down for repairs and the facility had switched to an emergency nitrogen supply. Failure to switch back to service air when it became available, led to the mishap.

The emergency supply became depleted and two valves in the normal nitrogen purge system failed in the open position, releasing the high-pressure nitrogen gas from the manifold into the liquid hydrogen tank. The gas flow raised the liquid hydrogen tank pressure to 4.5 psig. That was sufficient to rupture the bulkhead wall.

Incident Date
Jul 08, 1993
Setting
Equipment
  • Hydrogen Storage Equipment
  • Vessel
  • Piping/Fittings/Valves
  • Valve
Damage and Injuries
Probable Cause
Characteristics
When Incident Discovered
Lessons Learned

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 in pressure or vacuum systems.