I am a bit familiar with API-650 , but structural design of roofs remains my weak part.
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My questions :
How to design a floating roof (as a structural item:subjected to buoncy , puncture, and other loads)??

1/-Does anayone has some worked examples, or bits of litterature?
2/-Does Coade intending to include this design within Tank?

3/-Pontoon , single or double deck.
When to decide to go for double deck ??

4/-Who´s responsible for the design of the roof ??
Can a tank manufacturer subcontract this part ??
Or shall he keep it within his scope of fabrication ??

5/-When to go for aluminium roofs ???

6/-Who is responsible for designing the seal system??
Is it the seal supplier ??

My understanding is that: At the end the tank
manufacturer remains responsible for the WHOLE tank including roof, seal,..

As far as I am aware, the design of floating roofs is proprietary, with accepted procedures known to only a few companies. I have not encountered a design procedure in a code, a text, or engineering publication.

Until such a procedure is published, COADE can not attempt to add this capability to its software.