CA-Corr.Allowance for C.S piping

[nomankahn76]

Hi All
There is a question causing little confusion.
when we are saying we have a CA=3mm with Wall.Thk=10mm
what does it means??? it is like in total 10mm pipe thickness we have 7mm wall thick + 3mm CA or it's mean that we have to add CA=3mm in to wall.thk=10mm to get total=13mm along with CA???

As by defination CA is an addition to Wall.thick
Thanks
Kahn

 

[desertfox]

Hi nomankahn76

Normally I would work out the wall thickness required and then add the corrosion allowance, so if someone said they had a 3mm CA and the wall was 10mm thick I would assume the required thickness for pressure was 7mm.

desertfox

 

[metengr]

BY definition in Code and Standards, corrosion allowanace is a stated thickness. Total thickness = minimum required for design + corrosion allowance (if required or specified).

 

[MJCronin]

I agree with metengr....

But I would add that, the purpose in keeping the two thicknesses as seperate is to enable someone in the future to have an "allowance" for predition of component life.

Thus, if the code wall thickness is 7 mm, an inspector can test at various locations with this number as the minimum acceptable wall thickness.