REG NASA-LLIS-0620-1999 Lessons Learned Indoor Freon 113 Spill.pdf

1、Lessons Learned Entry: 0620Lesson Info:a71 Lesson Number: 0620a71 Lesson Date: 1999-04-08a71 Submitting Organization: WSTFa71 Submitted by: Jan JungewaelterSubject: Indoor Freon 113 Spill Description of Driving Event: Upon closing a Shuttle AC Motor Valve during a cycling test, the pressure force di

2、fferential across the valve deformed the Teflon interface a1dapter for a butt joint at the valve outlet port. The valve slipped free at the inlet port and approximately 160 gallons of Freon 113 was sprayed into the room at 250 psig and 56 gpm. Employees there immediately evacuated the room and suffe

3、red no ill effects. There was no equipment damage, but the Freon and productivity losses were costly.Flow benches and tooling for several components were supplied together by the original equipment manufacturer (OEM) to transfer repair operations of these components to WSTF. Safety reviews, subseque

4、nt modifications, and personnel training for the motor valve addressed only a valve using a slip joint upstream and a butt joint downstream to facility lines. No other configuration of this valve was known to the reviewers or specifically identified by the OEM to WSTF.An engineer new to the project

5、received a valve with a smaller diameter outlet port for which the OEM had used the adapter to make the butt joint with the facility line. Because the adapter was already available among the tooling, the new project engineer believed it had been included in the system reviews, when it had not been.

6、The OEM, in addition, had recently changed the material from which the adapter was made, from stainless steel to Teflon, to avoid scratching the valve, but transferred ownership prior to using the Teflon adapter and realizing its potential for failure.Losses and hazards were maximized because the su

7、pply valve to the Freon tank was inaccessible, being in the direction of spray, and there was no isolation valve on the supply tank. In addition, the emergency instructions did not explicitly address significant Freon leakage.Lesson(s) Learned: Provided by IHSNot for ResaleNo reproduction or network

8、ing permitted without license from IHS-,-,-1. When accepting inherited systems, carefully consider the application and associated hazards of each part.2. 3. Fluid release should always be considered a “credible hazard.“4. 5. Freon may be considered a relatively benign substance by personnel accustom

9、ed to handling much more toxic chemicals, but it can impose a great hazard in a closed environment, and/or in large quantities under high pressure.Recommendation(s): 1. Perform a risk analysis on Freon containment systems with special consideration given to the greatly increased cost of Freon loss s

10、ince original installation.2. 3. Ensure flexible systems are secured against pressure force differentials.4. 5. Ensure personnel understand the scope of safety reviews and can recognize potential out-of-scope conditions.6. 7. Ensure all tools are identified and included in safety reviews.Evidence of

11、 Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): N/AAdditional Key Phrase(s): a71 Hazardous/Toxic Waste/Materialsa71 Safety & Mission AssuranceAdditional Info: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Approval Info: a71 Approval Date: 1999-04-15a71 Approval Name: Ron Montaguea71 Approval Organization: NA3a71 Approval Phone Number: 281-483-8576Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-