EN 10253-4 Type A vs Type B and Seamless vs Welded

Hi all Piping designers,

I'm starting a projet where the client piping class uses fittings according EN 10253-4.

The piping class is divided in Seamless/Welded. Form DN15 to DN125 are Seamless fittings and form DN150 to DN600 are Welded.

After reading the Standard EN 10253-4 and some research on the Internet I understood the idea of Type A vs Type B fittings:


Now I have some doubts regarding Seamless vs Welded fittings that I can’t find an answer.

For example for the Tees we have this four Figures:


So my doubts are:
- Figure 4 and Figure 5 are only for Seamless Tes or can they also be welded?
- Figure 7 Branch welded Tee can also be Type B?
- Should I use from DN15 to DN125 seamless Figure 4 and Figure 5 and DN150 to DN600 Welded Figure 7?

Thank you all fore the help.

Best regards,
John