REG NASA-LLIS-0226-1993 Lessons Learned - Valve Seats.pdf

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1、Lessons Learned Entry: 0226Lesson Info:a71 Lesson Number: 0226a71 Lesson Date: 1993-06-21a71 Submitting Organization: LERCa71 Submitted by: S. PapellSubject: Valve Seats Description of Driving Event: A tube trailer was being filled with oxygen with a 1000 psi differential between the trailer and sup

2、ply when a flash was observed in the area of the remotely operated control valve. A subsequent rush of gas and fire followed. The fire continued for about 40 seconds and was extinguished by the onrush of gas from the ruptured stainless steel manifold lines that had been burned off.The investigating

3、board concluded that the nylon seats in the valve had deteriorated to the extent that the ball was able to vibrate freely under the high flow conditions present. The vibration would most likely be severe while attempting to flow oxygen against a closed ball valve with missing or deteriorated seats.

4、This would have generated sufficient energy through impact and heat to cause ignition.Lesson(s) Learned: Nylon seats deteriorate when used in valves controlling oxygen gas systems and can cause fires.Recommendation(s): Replace all nylon valve seats used for oxygen service with material that is compa

5、tible with oxygen.Evidence of Recurrence Control Effectiveness: 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 Energetic Materials - Explosive/Propellant/Pyr

6、otechnica71 Explosives Handlinga71 Parts Materials & ProcessesAdditional 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-,-,-