Steam generator to steam room suitable pipe and fittings

Which types of pipes, 1/2" BSP threaded fittings, sealants and washers are suitable to carry steam from a 2.8kW steam generator to a steam cabin, a pipe distance of 400mm?

Originally I was thinking 15mm copper pipe soldered onto 15mm x 1/2" BSP female tap connectors (the type with the red fibre washers) on each end.
Are red fibre washers suitable for steam?

Anyway, from a bit of googling, steel pipes are usually used to carry steam as steel expands less than copper. The expansion could cause problems on the end fittings if there is no room for movement but this is only 400mm? Also steel fittings will need brazing rather than the usual pipe soldering. Just adds to the costs. I'm not sure if compression fittings are suitable for steam. I know some plastic pipes and fittings are not suitable.

When I use to do steam rooms we used 28mm from the generator to the steam outlet and compression fittings.

Was that 28mm in copper or stainless steel?
Did you need any sealant / compound / tape on the compression olives?

28mm copper and no.

Read the installation instructions.
The steam output is to a permanently open end, and therefore does not generate a pressure much above 1 or 2 inches water gauge, so compression or soldered fittings on copper pipe are perfectly adequate.
The instructions will invariably instruct you to avoid any low points where condensate could gather; that is the pipe should have a fall to the steam room throughout its entire length.

MM

PS... For a 2.8kW generator 15mm copper will be sufficient for a 400mm run.