ULC S601-07 is a Canadian National Standard that covers the design of Shop Faricated, Single & Double-walled, Horizontal & Vertical A/G Storage Tanks. It is a "cookbook" standard (just like API 12F is) and allows no freedom of design. The manufacturers of these tanks must be certified by ULC and the tanks must bear a ULC Label. (just like UL). Because there is no freedom of design, if you specified a corrosion allowance, the manufacturer would have to add it to the specified thicknesses and probably would have to order thicker material if he did not stock it. This is also the only recognized Standard in Canada for double-wall tanks.
By the way, there is a later version, ULC S601-09.

FTank...

I would like to add that the people who write the UL code regarding shop fabricated and coated tanks assume that you are going to fill them with fuel oil and locate them indoors. (Modest corrosion conditions)

Does a corrosion allowance requirement make much sense for tanks built to this set of rules ?

-MJC

   

MJ Cronin

Quite the contrary, in Canada the majority of these tanks are located outdoors, though I do agree that the majority contain gasoline, fuel oil or some other hydrocarbons. I don't understand your reference to indoors and modest corrosion. Are you suggesting exterior corrosion if they're installed outdoors? I assumed that xema77 was referring to a tank interior corrosion allowance.

These tanks are also used for storing chemicals and most of those times are interior coated with thin film epoxies which in those cases, adding a corrosion allowance doesn't make much sense.

However, since xema77 didn't respond, we may never know!

FTank

It is an outdoor diesel storage tank and I was refering to an internal corrosion allowance.  I had been led to believe that ULC S601-07 may have a corrosion allowance inherent in the design, however could not find anything to confirm this.  Therefore I assumed, as FTank confirmed, that a CA would have to be added to the ULC thickness.  I will review if the CA makes sense for diesel storage.  Thanks for your posts.

FTank,

You mention about a new revision of ULC-S601. I was unable to find it on the web. Do you know where to find ULC-S601-09?   

AK8824
Go to:

www.ul.com/canada/eng/pages/ulcstandards/