As sson as you mention Codes you've covered the other 3 issues. There is a DIN code which has been well ironed out over the years after some earlier shortcomings. It's numbered down in the 4 figure listing, 1024 or thereabouts. There's an ISO version hopping about as well as a few API Storage Tank Codes thrown in; for good measure...

If you quote the applicable Code on your drawings it is always a good idea to make sure the details match up. Its amusing to see how many don't.

You will also have you satisfy the local regulations concerning seismic activity & fire/explosion prevention techniques. ■