1、Lessons Learned Entry: 0457Lesson Info:a71 Lesson Number: 0457a71 Lesson Date: 1995-09-17a71 Submitting Organization: JSCa71 Submitted by: Ronald A. MontagueSubject: Safety Engineering Analysis of Low Hazard Systems Interfaces with High Hazard Systems Description of Driving Event: During repressuriz
2、ation of a test chamber, ammonia in a test article heat exchanger froze resulting in rupture of the exchanger. The rupture caused pressure to build up in a second test support unit. This second unit had a pressure relief valve, which was released when the pressure exceeded the upper limit, spilling
3、ammonia into the work environment. The facility had to be evacuated.The root cause of this mishap was failure to treat “low hazard“ systems, when connected to ammonia systems, as ammonia hazard systems. Had this been done, the design of the relief valve would have been configured to preclude direct
4、venting of the valve into the facility work environment.Lesson(s) Learned: Low hazard systems must be addressed by supporting safety engineering analyses (failure modes and effects, hazard analysis, etc.) to identify vulnerabilities at the interface with high hazard systems. Such analyses will ident
5、ify the need for additional and/or modified controls.Recommendation(s): 1. Include other organizations in emergency drills and enact responses to emergency scenarios.2. Notifying supporting areas of hazardous materials usage including attachment of a Hazardous Materials Statement to the Area Notific
6、ation Memo.3. Obtain test management training on JSC site emergency procedures and organizational response.4. Prepare emergency kits to retreat to if driven from primary test areas.5. Incorporate failure modes and effects analysis and/or hazard analysis to check fluid interfaces, freeze points, and
7、rupture areas including effects of failure.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-6. Permanently amend operational checklists to restrict personnel access above 2nd level during testing.7. Amend test facility guidelines (including those for
8、test build-up) to discuss relief valve rules pertaining to safety and human factors.ALL ABOVE RECOMMENDATIONS HAVE BEEN IMPLEMENTED.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Emergency Preparednessa71 Faci
9、litiesa71 Hazardous/Toxic Waste/Materialsa71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 1996-09-30a71 Approval Name: Ron Montaguea71 Approval Organization: JSC/NA3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
