Flue for fiul

[Gyn_Paul]

I'm planning to site the fioul chaudiere in the barn on a concrete plinth with the tank adjacent behind a bund wall. Can I use a flexible inox flue (suitably and frequently supported, of course) from the 'T', or must I use rigid sections?

Also, on a bare barn wall of some 40ft hight what are the regs concerning termination Height, and can I top it with an ordinary chapeau inox?

p