MikeHalloran: Thanks for the response. I have a client asking for "material for instrument tubing shall be stainless steel with a safety factor of 6:1". It didn't mean anything to me either.
Maybe some context is missing. I might guess that the customer intended a minimum fs of 6 for bursting against the design pressure.
Actually, I might ask the customer to explain in more detail what he means, because it doesn't _say_ minimum. That's sort of implied by 'factor of safety', but lawyers could argue it either way.
To demonstrate compliance with a strict interpretation of what's written might have you using foil tubing, and I don't know where to get it or how to terminate it.
How many lawyers does your customer currently own or rent?
So does the next sentence give you the maximum possible system pressure?
No, they have some explaining to do. I would think that the mean that the stress from service pressure should be no more than 1/6 of the theoretical burst pressure......but....
Should it be based on the minimum strength? What are you to use for the pressure? Any fatigue considerations? How do they rate fittings?
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Rust never sleeps
Neither should your protection
SAFETY FACTOR – The standard safety factors indicate
three grades of severity of service:
4:1 –mechanical and hydraulic shocks not excessive
6:1 –considerable mechanical strain and hydraulic shock
8:1 –hazardous applications with severe service conditions
