1、Lessons Learned Entry: 0237Lesson Info:a71 Lesson Number: 0237a71 Lesson Date: 1993-07-08a71 Submitting Organization: LERCa71 Submitted by: S. PapellSubject: Control Valves Description of Driving Event: A test Centaur 1-E tank, on standby, was damaged. The bulkhead between the liquid hydrogen tank a
2、nd the liquid oxygen tank failed due to a series of events. Air services to the building were shut down for repairs so that the facility 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 a
3、nd 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.Lesson(s) Learne
4、d: Fail-safe position of control valves in supply lines must be set correctly to prevent damage to pressure vessels.Recommendation(s): Set all valves for fail safe operation (open or closed) according to needs before installation in pressure or vacuum systems.Evidence of Recurrence Control Effective
5、ness: N/ADocuments Related to Lesson: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Pressure VesselsAdditional Info: Approval Info: a71 Approval Date: 1994-04-19a71 Approval Name: Maria Havenhilla71 Approval Organization: LERC/EBASa71 Approval Phone Number: 216-977-1483Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
