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Design allowance for Aging

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kdt

Mechanical
Joined
Apr 24, 2001
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7
Location
CA
Can anyone provide a reference for design factors/allowances used for the increased roughness factor of a pipe for the design life of the system when calculating the pressure drop?

Are there any rules of thumb?

I have heard of using 5 times or 10 times roughness factor for aging of pipe but have not seen any reference material regarding this. Is this common practice and is this good practice?

I have some concerns with this as depending on the process and pipe materials, there will be different corrosion rates.

Say I am designing a process water pipeline to a plant with a 25 year design life. I have already calculated pressure drops based on clean piping. Do you recalculate at a greater roughness (of 5times clean pipe roughness)?

Same question but for hydrocarbon?

 
Check ANSI 31.4 for liquuid oil lines
ANSI 31.8 for gas lines

Greg Akhibi
SPDC Nigeria
 
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