I am currently involved in projects

[shani08me04]

I am currently involved in projects related to API 12D and API 12F storage tanks. However, these standards do not account for the corrosion allowance. My inquiry pertains to whether the specified thicknesses in these standards require the incorporation of a corrosion allowance?

 

[JStephen]

It's been a while since I checked, but I was thinking both standards did allow for a CA to be specified- simply added to the specified thickness.
In general, none of the standards (API-650, ASME, etc) require a corrosion allowance, it is always specified by the owner, and may be zero in cases where it the service is deemed not to require it.

 

[shani08me04]

@JStephen
API 12D and 12F neither mandate nor prohibit the inclusion of a corrosion allowance. I[tt][/tt]n contrast, API 650 and ASME standards explicitly endorse the incorporation of a corrosion allowance. Given this disparity, I am inclined to believe that considering a corrosion allowance might not be necessary in the context of API 12D and 12F.

 

[LittleInch]

" I am inclined to believe that considering a corrosion allowance might not be necessary in the context of API 12D and 12F."

That's a dangerous statement without any knowledge of the corrosivity of the fluid or past performance of tanks holding that liquid.

If you read 12D and 12F, they make it quite clear that these are just "general purpose" tanks for the petroleum industry, but this does not absolve the duty of the designer / purchaser from making sure they are fit for purpose for your particular use. If you want to add a CA then add it.

You don't actually say what corrosion allowance you were thinking of?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JStephen]

I think the difference you're seeing is that API-650 and ASME have equations to determine thickness, so the corrosion allowance is included in those equations. But the CA is always determined by the use, and may range from zero to 1/4" or more depending on the application.
In contrast, API-12D and API-12F simply state the thickness, rather than having the user calculate the thickness, so you don't see the CA in the equations since there isn't any equation. But still, if CA is required/desired, that is specified by the user and added as needed.

 

[LittleInch]

And the costs are quite different.

If an API 12 d/f tank starts leaking they either internally line it or scrap it. So long as its done 8 to 10 years its cost has been written off a long time ago. Large 650 tanks are completely different.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.