Pipe sizes are universal, with no difference based on material. For some reason I have no desire to research, 1/2" pipe is .840 in diameter. IIRC, and it has been 18 years since I worked with this information, all 5/8 pipes are .940, while 3/4 comes in at 1.05.
Edwin Haroldson
Loremaster
Master of the Mages' Guild
An ethical person does the right thing when no one is watching.
OOG - Charlie Spiegel - Kitchen Marshal
"War is a matter of vital importance to the State..."