asme b31 "corrosion allowance value"
asme b31 "corrosion allowance value"
(OP)
hi all
would please some one help me how to get an exact value for corrosion allowance (A) for carbon steel different sizes pipes to use it to get minimum wall thickness
many thanks in advance
would please some one help me how to get an exact value for corrosion allowance (A) for carbon steel different sizes pipes to use it to get minimum wall thickness
many thanks in advance





RE: asme b31 "corrosion allowance value"
RE: asme b31 "corrosion allowance value"
Everything else is at best an estimate based on past performance or adaptation of, for example CO2 corrosion. Even then depending on which method you choose you can get wildly varying numbers.
So there are few if any nice simple formulas or numbers, so a lot of piping systems simply apply 0, 1 or 3mm Corrosion allowance depending on the service. If they think that would be inadequate then the materials engineers, who you really should be talking to would normally recommend some other material.
I note you say "B31". B31 encompasses many different codes. Piping for example works one way, but pipelines can often allow for injection of Corrosion Inhibitor and then you get to argue about the "efficiency" of the said inhibitor or indeed how much of the time the inhibitor is able to operate.
Does that give you enough to think about?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: asme b31 "corrosion allowance value"
1. Ask your boss/supervisor/mentor the question: "I have this system (fluid, pressure, operating temperature, duty cycle time in service (if not continuous!), environment, pipe metal alloy. It must serve for 10, 20, 30, 40 years. Where do i look up the required minimum corrosion allowance?"
2. If you do choose NOT to display your courage by asking a well-thought out question after you have determined all of the important variables involved (see above) to the very people who should be telling these things, then WRITE your ASSUMPTIONS clearly at the start of your pipe calculation record.
Assumed corrosion/erosion allowance = 0.062 inch based on assumed ___ (fluid) at ____ (psig) at ____ (degrees F) running for ____ (years) at maximum flow velocity of ____ ft/sec in _____ alloy.
REMEMBER! Do NOT ask them for all of the variables! Be able to ask them (him/her/they/it) for the single answer to the single problem you need AFTER you have found the limitations.
(Likely, it will be in the project specifications (from the client) or from your company's (private) source files for previous projects. )
RE: asme b31 "corrosion allowance value"
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: asme b31 "corrosion allowance value"
Fluid, max.temp, max.press. CO , branches etc.
RE: asme b31 "corrosion allowance value"
Have you ever thought that the OP has been asked to produce a pipe spec???
RE: asme b31 "corrosion allowance value"
The first man in a company to produce a pipespec.?
RE: asme b31 "corrosion allowance value"
Just for your edification new pipe specs are written everyday by some Companies and as the basis a corrosion allowance needs to be established!!!!
RE: asme b31 "corrosion allowance value"
RE: asme b31 "corrosion allowance value"
RE: asme b31 "corrosion allowance value"