If you are the design authority, you may select whatever you like based upon the intended use of t he product unless there is some jurisdictional law requiring parts be designed, manufactured(built), inspected and tested in accordance with a specific standard..
AWS Has numerous codes and standards that may be applied to your product. Obviously using one for structural steel for stainless sheet metal will lead to eventual problems. Not with the product per se but with the documentation that supports it and may be passed on to customers or subcontractors.
Take a LOOK AT
https://en.wikipedia.org/wiki/List_of_welding_codes AND JUST PICK YA ONE OUT :)