30 cm cheers bro
A kitchen WASTE pipe is 11/2" in many codes which is utter stupidity as the kitchen WASTE line does become reduced with grease and soap scum deposits
If the WASTE piping is going under ground to connect to the SOIL line (sewer piping) then 2" is strongly recommended as snaking an 11/2 line can be very challenging as the fittings are very short radius
Depends on locality as many of the one family homes require I install sewer mains from 4" - 6". The size of the "sewer" is based on fixtures units that are connected and to local codes
Size of any drain is calculated by fixture units (7.48 gallons) and pitch of pipe with many codes giving a bare min sizes
4"
If the drain is used as a wet vent for another fixture 2". Otherwise 1.5".
1-1/4" is typically the diameter of a bathroom lavatory drain pipe. 1-1/2" is more commonly the drain pipe size in kitchen sinks.
2"
It should be 3" minimum, preferably 4.
I would use 3 inch for that.
3" house (building) drain allowable. 4" building sewer line needed for house from sewer main.
a 3 inch pipe
At least 3 in. drain pipe
because my a buthole is about the size of a sewer pipe... thats what 3 years in prison gets you!