Stainless Steel Pipe thickness calculation 1

[tribleprince]

is there any need to add Corrosion allowance to the SS Pipe(316L)during its thickness calculation(one of my collegue says that SS is already corrosion Resitant so there isnt any need to add corrosion allowance but i m skeptical).
Since ASME B31.3 doesnt specify this.it gives us general Straight Pipe thickness calculation.

 

[TD2K]

That's the designer's call since there are too many variables to consider. SS is only resistant to corrosion, it's not proof against it especially in the wrong service so I would definitely not say "SS = no corrosion allowance needed".

That said, I've not typically seen much corrosion allowance added to SS piping. Usually the minimum thickness is calculated and reviewed against the next commercally available size to see how much 'extra' there is. The SS cladding on vessels in corrosive service is usually not much and vessels will typically have quite a bit more corrosion allowance built into their design than piping.

 

[SJones]

If you are already spending more money on a corrosion resistant alloy (CRA), of which 316L is one, as compared to carbon steel, why would you want to go and spend more money adding an allowance that should not be necessary if the material has been correctly selected for the service in the first place? If you think you need a corrosion allowance, then the material has not been correctly selected.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04