Water running through these pipes tends to create a suction behind it and that suction can be.
Waste vent in attic.
Only two plumbing set ups could require sewer pipes in the attic.
Notice how the main vent and waste pipe remain separated behind the sink only connecting via the attached went pipe.
Extra info on the air admittance valve.
This revert is at least six inches above the overflow line and properly connected with a drainage t.
The main vent is stack is often but not always a continuation of the soil stack which is a 3 or 4 inch waste pipe that extends vertically down from the uppermost bathroom to the sewer.
Waste is produced at fixtures such as toilets sinks and showers.
I see situations around like this sometimes.
The drainpipes are made of cast iron galvanized pipe copper or plastic.
Drain pipes are those connected to fixture p traps.
The vent pipes remove or exhaust sewer gases and allow air to enter the system so that the wastewater flows freely.
As the water runs down proper venting is required to avoid a vacuum from being created.
Vent pipes look like sewer pipes.
The first would be a bathroom or kitchen in that part of the house and the other would be a.
There are 3 vents in one area and 2 in another.
These empty into larger waste pipes that connect to the sewers.
I have a customer that we are doing some work in the attic for and i noticed yesterday that the plumbing is vented up into the attic phew and not thru the roof.