HerrKaLeun: your right my supply and return installation.
chicopee: you have a point.
Is there a standard from ASHRAE or any books that I can proof that both material can use.
is it possible to use black steel or copper pipe to be install chilled water piping in fan coil unit FCU and what standard I will use to justify that both can be use.
I would like to ask regarding the piping in FCU/HVAC, is it possible to install black steel pipe or copper pipe in the piping of FCU/HVAC and what standard I will use to justify that both can be use.