In areas exposed to snow or freezing or temperatures below 0 degf that can block a plumbing vent the vent pipe should be at least 2 in diameter beginning at least one foot inside the building in an insulated space before the vent passes through the roof.
Examples of 2 inch waste vent at roof.
Above roof plumbing vent diameter.
The fat pipes in your house make up the dwv carrying wastewater to a city sewer line or your private sewer treatment facility called a septic tank and field.
If they become blocked your system won t drain properly.
All open vent pipes that extend through a roof shall be terminated at least number typically 6 inches mm above the roof except that where a roof is to be used for any purpose other than weather protection the vent extensions shall be run at least 7 feet 2134 mm above the roof.
Both kitchen 1 1 2 inches and bathroom 1 1 4 inches are smaller than the rest of the drain system on purpose.
All open vent pipes that extend through a roof shall be terminated at least number inches mm above the roof except that where a roof is to be used for any purpose other than weather protection the vent extensions shall be run at least 7 feet 2134 mm above the roof.
When installing your vents it s highly recommended that you plan out your drain lines to minimize the risk of clogging.
Located on the roof these vent pipes allow gases to escape from your sewer system.
The required size of the drain shall be determined in accordance with table 710 1 2 vent pipes shall not be less than 1 1 4 inches 32 mm in diameter.
They lead into larger branch drain pipes which lead into the 4 inch stack.
Plumbing vents need to be straight on the vertical.
Section 904 vent terminals roof used as.
The diameter of individual vents branch vents circuit vents and relief vents shall be not less than one half the required diameter of the drain served.
904 1 roof extension.
Concluding the example we will assume the restroom has its own vent to the roof with a total piping length of 25.
Branch drainpipes of smaller diameter typically 1 1 2 or 2 inches carry water from specific fixtures to a stack.
Vents exceeding 40 feet 12 192 mm in developed length shall be increased by one.
When there is a bend in the vent pipe moisture accumulates and is trapped.
Here s a closer look at this issue.
Consulting ipc table 916 1 see figure 4 we see that for a 4 waste stack with a dfu up to 140 and with 27 or less of vent piping length the correct vent pipe size is 2.
This is necessary to avoid any vapor locks from occurring.
The centerpiece of a dwv system is the main stack usually a pipe 3 or 4 inches in diameter that runs straight up through the roof.
Because the vent pipe is the warmest pipe in the house all year long the moisture that is trapped in a bend may turn to vapor and cause a vapor lock.
Figuring out your drain waste vent lines if you have to make plumbing repairs around your home it helps to understand your drain waste vent system dwv.
