REG NASA-LLIS-1069-2001 Lessons Learned Use of Quick Release V-Band on Pressure Vessel.pdf

1、Lessons Learned Entry: 1069Lesson Info:a71 Lesson Number: 1069a71 Lesson Date: 2001-04-18a71 Submitting Organization: GRCa71 Submitted by: John Thomas / John KoudelkaSubject: Use of Quick Release V-Band on Pressure Vessel Description of Driving Event: Safety Mishap on the KC-135. An experiment rig t

2、hat is flown on the KC-135 utilized a quick-release V-band to seal a pressurized chamber. The chamber was used to conduct combustion experiments during the KC-135 flight. The v-band was implemented in order to permit quick and easy access to the chamber interior in order to change samples and access

3、 interior components and instrumentation. During the KC-135, the V-band was released when the chamber was still pressurized. Once the V-band was released, the chamber lid was propelled off the chamber and across the planes cabin area. The lid just missed one of the experiment operators and caused da

4、mage to one of the planes interior lights. The experiment operation procedures had steps to identify relief of pressure, but those were skipped, and the V-band and chamber lid design contain no other lid retention element.Lesson(s) Learned: Pressurized containers that use quick-release V-bands need

5、to have an additional lid restraining element or pressure interlock. A lid restrain needs to capture the lid in the case the V-band is released when the chamber is pressurized. A pressure interlock would maintain the lid seal integrity whenever the chamber pressure is above the external atmosphere.R

6、ecommendation(s): Chamber and lid were modified to provide a mechanical obstruction that would capture the lid if the V-band was released when the chamber was pressurized. The obstruction permitted the lid to break the seal and relief the pressure but limited its travel / separation to prevent any s

7、afety issue. The procedures were also modified to make the chamber relieving steps more obvious.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: The experiment rig was flown again in with no mishap, mainly

8、 due to the procedural changes. The lid restraint was verified to its ability to keep the lid from being a loose itemDocuments Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Facilitiesa71 Hardwarea71 Haza

9、rdous/Toxic Waste/Materialsa71 Pressure Vesselsa71 Risk Management/Assessmenta71 Safety & Mission Assurancea71 Test Articlea71 Test FacilityAdditional Info: Approval Info: a71 Approval Date: 2002-01-07a71 Approval Name: Jim Cerya71 Approval Organization: GRCa71 Approval Phone Number: 216-433-3002Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-