The plumbing vent, also known as a vent stack. In residential plumbing system, drain and waste pipes carry water and wastes to the sewer system; sewer gases expel from the vent pipes while equalizing the system’s air pressure. Just as drain pipes remove water and waste from your home, the plumbing vent pipe also known as a plumbing air ventand removes gas and odours. It also allows fresh air into the plumbing system to help water flow smoothly through the drain pipes.As mentioned, the air pressure in sewer pipes is the same up and down the length of the pipe. But when water moves through the pipe, it compresses the air ahead of it, creating a positive pressure. This pressure buildup must be released somehow, or the positive pressure will push back on the water. If the air were allowed to push back, this would cause the wastewater to back up through the plumbing fixture and come out the drain, which would have obvious health consequences, to say nothing of the odour. However, no water runs through the plumbing vent pipe. It is a vertical pipe attached to a drain line and runs through the roof of your home. The vent stack is the pipe leading to the main roof vent. It channels the exhaust gases to the vent and helps maintain proper atmospheric pressure in the waste system.
Wet venting is a method of protecting the trap on a drain pipe on multiple plumbing fixtures. It is a useful method of venting and can save pipe, fittings, time and money. Wet venting is most common in conjunction with toilets and sinks; the drain for the sink and toilet.