Plumbing Vent Pipe Size

Horizontal vent pipes forming branch vents relief vents or loop vents shall be at least 6 inches 152 mm above the flood level rim of the highest fixture served.

Plumbing vent pipe size. Above the roof plumbing vent height. Both kitchen 1 1 2 inches and bathroom 1 1 4 inches are smaller than the rest of the drain system on purpose. Vents exceeding 40 feet 12 192 mm in developed length shall be increased by one nominal pipe size for the entire developed length of the vent pipe. You can connect the kitchen vent to the main vent in the attic as long as the main vent is the proper size and extends through the roof.

The table indicates that the minimum slope for a building drain with 44 dfu is 1 8 per one foot of pipe and the minimum pipe diameter at 1 8 slope is 4 finally you can use ipc table 916 1 see figure 4 to size vent piping using the dfu values from step one and waste stack sizes from steps two and three. When installing your vents it s highly recommended that you plan out your drain lines to minimize the risk of clogging. Drainpipe serving a single family home needs a main vent that is at least 1 1 2 in. Vent pipes shall not be less than 1 1 4 inches 32 mm in diameter.

It is important to note that the 2006 ipc has a definition of vertical pipe as any pipe which is 45 or greater from horizontal. They lead into larger branch drain pipes which lead into the 4 inch stack. Vent pipes should extend to outdoors above the building roof and should terminate vertically not less than 6 above the roof surface nor more than 24 and must be at least 12 from any vertical surface such as a nearby sidewall.