Hello;
First time here. Remodeling our bathroom. No new fixtures, but new locations will be further from vent pipes. Can I overcome the critical distance limitations by increasing the vent pipe size? For example, looks like current toilet flange is 3 feet from the 2" vent pipe, new location will be 7' away, can I increase vent pipe to 3" and be OK? If so, does the new increased size have to be for the entire pipe length or just to the first Tee? Thanks, Art
COMMUNITY FORUM
The reasons you have a limitation on the vent distance, is because plumbing is designed to eliminate the siphonic action that occurs. A siphon is developed inside a fixture when it flushes. The vent breaks that siphon, so the fixture doesn't completely siphon each time it empties. National standards vary on the distance for toilets (since there are 7 national and regional codes). The basic premise is the length can't exceed the inside diameter. For each foot the pipe travels, it goes up 1/4". In a 3" horizontal pipe there are 12 quarters. In order to have a air travel across the top of the water, you need to have 1-1/2 of space above the water. That means you only get 6 quarters to use in a 3" pipe. Most areas allow you to travel 6' with a 3" pipe and 10' with a 4" pipe, although some areas have made the code 4' for a 3" and 5' for a 4".
Raymond VinZant Plumbing Prof.
Raymond VinZant Plumbing Prof.
