What is a soil vent pipe?
A soil vent pipe (SVP), also known as a soil stack pipe or a drain-waste-vent (DWV), is a pipe that runs vertically from a property’s underground drainage system to the top of the property, just above the level of the roof gutter. SVPs are typically found outside the home, however some internal SVPs, which are usually fitted inside the property’s outer wall, also exist.
SVPs are generally plastic, although many older pipes have been constructed from cast iron.
How does it work?
It is installed to transport waste from upper floor toilets, baths and sinks into the underground drainage system. However, the attached vents also allow smells and odours from the waste and drainage system to be released above the home, rather than inside it, and in an area that won’t offend any bystanders.
The pipe’s vents also facilitate the process of aerobic sewage digestion by letting oxygen into the pipe system.