Corrosion Allowed for an Old EFR

[TANKO]

Good Morning to all,
i have a question. In a terminal where i'm working, we would to do the thickness control of the External FLoating Roof of an hold tank. We don't have drawings about that tank.
Does API provide acceptability percentages for the thickness test?

Thank you very much in advance

regards

 

[JStephen]

I see no specific requirement in API-653, except for a rim plate minimum in 9.14.6.2.