~What are the diameters of the tubes in the US? Here standard diameters for copper tubing in domestic set ups are 12, 15 and 22 mm. Oddly enough when threaded connectors are used we still have inch sizes: 3/8", 1/2", 3/4" etc.
Here is what my house has (a one-family residence) which I believe to be fairly typical.
Using 2.54cm per inch, & rounded.
1.00 inch service main (25mm)
0.75 inch "main branch" (19 mm) and outdoor hose-cock for watering.
0.50 inch branch (13mm) where all three bathroom fixtures- (we don't do bidets here, usually) feed from a 0.50inch pipe that feeds from the 0.75 inch main branch.
Drain piping is typically:
1.25 inches (32mm)for a bathroom drain
1.50 inches (38mm) for a kitchen drain
2.00 inches (51mm)for a steam-supply pipe (home heating)
4.00 inches (102mm) for a water closet and also a dryer vent hose.
Diameters shown are all I.D. (inside diameter) thickness of pipe is determined by "Schedule 10" and "Schedule 40" an explanation for which I am lacking right now.
Do fluorescent tube in metric lands run:
2 feet (24 inches) 61cm?
4 feet (48 inches) 122cm? (1.22m)?
8 feet (96 inches) 244cm? (2.44m)?
~Oddly enough when threaded connectors are used we still have inch sizes: 3/8", 1/2", 3/4" etc.
Speakign of which, our light-bulbs (lamps) use a "standard" Edison-base threaded connection. I'm sure it's sized using the English system. Light-bulbs by GE (and perhaps Philips) fit, but the "international" imitations that are probably metric in size but very close-- go in but shatter on their way out. I personally won't use anything but GE!