One end in most cases the inlet is 4 inches wide this mounts to the toilet and the outlet end is 3 inches in diameter.
Water closet pipe size.
The supply pipe shall extend to the floor or wall adjacent to the fixture.
The fixture supply pipe shall terminate not more than 30 inches 762 mm from the point of connection to the fixture.
A reduced size flexible water connector installed between the supply pipe and the fixture shall be of an approved type.
Closet bend 4 3 closet bend connects to 3 inch schedule 40 pipe.
1 inch 25 4mm 1 ft.
The closet bend actually has two diameters because it connects the 3 inch drain pipe to the 4 inch drain line.
Toilet water supply line 1 2 inch copper pipe or plastic pipe routed from main water line or 1 2 inch cold water line.
This pipe fitting is set under the toilet in the floor joists or ground in toilets on concrete slabs.
The minimum size of a fixture supply pipe shall be as shown in table 604 5.
Appliances appurtenances and fixtures not referenced in the table below shall be permitted to be sized by reference to fixtures having a similar flow rate and frequency of use.
A reducing closet bend configuration or a 4 3 closet bend has two different sized ends to connect two different sized pipes.
So pipe area should be at least equal to water flow rate divided by eight.
Water velocity should not be greater than 2 438m s at valve seat to prevent noise and erosion.
The top of the closet bend is 3 inch diameter pipe while the other end is 4 inch.
Most toilet installation parts are made to fit these pipe sizes.
Unit sizes provided in the table 1 and table 2 is in mm but the size of pipes in the chart is in inch.
Water supply fixture units wsfu and minimum fixture branch pipe sizes.
304 8mm 1 gallon m 3 785l m.