It is much easier in danish then. We only have one word:
tube = rør
pipe = rør
(don't know if your computers show the letter ø, but it is a o with a line going through the middle)
water pipe = vand rør
square tube = firkant rør
We also messure a water pipe ID and this is one of the only messurements were we still use inches. When we say ex. 1/2" pipe it is a normal iron water pipe.
Hydraulik pipes are messured on the OD and is always in millimeter.
Square or rectangular tubes are messured also on the OD and always in millimeter.
Copper, brass and aluminium pipes or tubes are always messured OD and in millimeter.
Seamless pipes are messured on the OD and is always in millimeter.
Edited by Per, January 11, 2013 - 09:10 PM.