REG NASA-LLIS-0047-1991 Lessons Learned - Mercoid Pressure Switch Inadvertent Water Deluge Activation.pdf

1、Lessons Learned Entry: 0047Lesson Info:a71 Lesson Number: 0047a71 Lesson Date: 1991-12-19a71 Submitting Organization: KSCa71 Submitted by: David PenningtonSubject: Mercoid Pressure Switch; Inadvertent Water Deluge Activation Description of Driving Event: The primary cause of the mishap was an activa

2、tion (closing) of the fire pump mercoid pressure switch which prematurely started the fire pump. This produced transient pressures that exceeded the 2:1 mechanical advantage of the deluge valves, forcing them open. The switch activation was caused by potable water system pressure fluctuations extern

3、al to the local facility.Lesson(s) Learned: 1. Mercoid pressure switches are overly sensitive to system pressure fluctuations and may cause inadvertent activation (switch bouncing).2. Water deluge systems are unable to adequately absorb water line transients, thus jeopardizing the integrity of the v

4、alves & pump controller switches.Recommendation(s): 1. Protect systems that utilize mercoid switches from pressure transients to prevent inadvertent activation.2. Provide a means to attenuate pressure transients and fluctuations to assure the integrity of water deluge system components.Provided by I

5、HSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directorate(s): a71 Space Operationsa71 Exploration SystemsAdditional Key Phrase(s): a71 Facilitiesa71 Fire Protectiona71 Grou

6、nd Operationsa71 Ground Equipmenta71 HardwareAdditional Info: Approval Info: a71 Approval Date: 1994-06-01a71 Approval Name: James G. Klinea71 Approval Organization: KSC/HEIa71 Approval Phone Number: 407-867-7614Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-