Revalidating Requirements: Rigging Hardware Case Study
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description
Revalidating Requirements: Rigging Hardware Case Study. Anthony Underhill 321-730-6269 [email protected] [email protected]. “ We ’ ve always done it that way? ”. Is the requirement still relevant (effective) in today ’ s environment?. - PowerPoint PPT Presentation
Transcript of Revalidating Requirements: Rigging Hardware Case Study
WHY DOES THE SAFETY REQUIREMENT EXIST?
“We’ve always done it that way?”
How was the requirement validated?
What were the circumstances at the time?
Is the requirement still relevant (effective) in today’s environment?
SHACKLE FOR CRITICAL LIFT APPLICATION
AFSPCMAN 91-710 ASME B30.26
Initial Proof 2 x Rated Load 2 X Rated Load*
Post Proof Inspection Volumetric & NDE Visual
Periodic (annual) Proof 2 x Rated Load Not Required
Periodic (annual) Inspection
NDE(Dye Penetrant)
(Magnetic Particle) Visual
FAST FORWARD TO TODAY
Facility Cost ⇒ $110K annualUser Mission Cost ⇒ $ 34K per mission
TOTAL COST ON Eastern Range = ~$1M per year
BUT IS IT MORE SAFE?
US NAVY – high number of accidents◦ Causes: Uncertainty in the load
High corrosion environmentNo Consensus standard for
design◦ Solution: Annual 2 x rated load test
OSHA in its infancy
US Air Force Range◦ Adopt 2 x RL in ESMC (1984)
1970 2000
Weak OSHA Strong OSHA
Inconsistent Design FOS Consensus FOS
Various materials Specific Materials
2 x rated test solution 2 x rated test solution
WHAT DOES ASME SAY ABOUT 2 x RL TESTING?
Do not recommend exceeding 42% yield strength or fatigue may occur (ASME B30.20 interpretation)
Does annual 2 x RL proof increase safety?
Are Magnetic Particle or Dye Penetrate inspections required to find critical flaws?
10 Fatigue Rated shackles failed in fatigue when subject to 2 x RL
BUST
E
D
Failed @ 2.87 x RL Failed @ 1.28 x RL
Failed @ 1.87 x RL Failed @ 2.28 x RLBUST
E
D
Chance of improperly tested Change of damage during installation Change of damage during installation
REVISIT YOUR SAFETY REQUIREMENTS
REVALIDATE THEY ARE FULLFILLING THEIR INTENDED PURPOSE
◦ YES – ENFORCE THEM◦ NO – CHANGE THEM
