Allowable corrosion limits

[jari001]

Hi everyone,

I have some outdoor storage tanks across my site that need some sprucing up. Most of the uninsulated flanges and nozzles have started to rust. For the most part, it has been minor surface rust that we've polished clean and painted or insulated. There are some flanges(2" and 3") that have, what I would say, moderate surface rust. I am wondering what references could show me design guidelines on allowable corrosion, meaning amount of material loss that is ok.

Material of construction for the flanges is SA105 C/S. Standard style flanges that bolt together.

Thanks,
J

 

[DSB123]

Well the corrosion on "your" site would need to be assessed under API 579 procedures!!!

 

[jari001]

DSB123,

I should have specified that the storage tanks are NOT pressure rated, my understanding is API 579 is for pressure vessels. As a general statement, flanges are carbon steel and they are not exposed to the stored material so I don't expect accelerated corrosion. The carbonn steel flange is exposed to rain, snow, and wind.