Retirement Thickness
Retirement Thickness
(OP)
Can anyone help with determining the minimum wall thickness required for structural strength (aka retirement thickness) for ASME B31.3 pipework?
I have manged to find some figures but these look to vary depending material, diameter, service and which company is involved and do appear to be that scientific. I was wondering if there is a technical specification that I could refer to?
I have manged to find some figures but these look to vary depending material, diameter, service and which company is involved and do appear to be that scientific. I was wondering if there is a technical specification that I could refer to?





RE: Retirement Thickness
RE: Retirement Thickness
As metengr says API579 is the way to go. You need to assess the total stress levels within the pipework, not just the pressure stresses. A company I used to work for would not allow the thickness to be less than 2mm. Anything less than that was repaired/replaced. This was considered the lower bound for structural strength.
RE: Retirement Thickness
Many thanks for your responses.
I can see that API 579 would be useful in assessing particular pipes that have been in service and have corroded/erroded.
What I am putting together is a number of new pipe classes and would like to report a retirement thickness even though the pipework is brand new. This is to give guiance to the operator. Hopefully that has clarified things?
I did manage to find an API report (attached).
RE: Retirement Thickness
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Retirement Thickness
The retirement thickness (tn - corrosion allowance) must be ternmined before the design starts. Once the corrosion allownac has be stated the designer will use tn-CA in the design process.
Kevin