Hi
could you please tell me that wheather the split tee is a pressure retaining part or it is just as a reinforcment ??
I had pland to weld a piece of 20″ pipe on 30″ header and then as a reinforcment fabricate a full or half saddel around header.
in this way the saddle is not a pressure retaining part and there is no need to have a circomfrencial weld.
two part of full saddel will be join together with two joining bar.
then weld a flange to 20″ pipe and and then 20″ full bore ball valve.
could anybody tell me if this is a practical design or not. 
highly appreciated your reply