- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 10 Jun 2019
Soil vent pipe
A soil vent pipe (SVP), also known as a soil stack pipe, drain-waste-vent or ventilated discharge pipe, is typically a vertical pipe that removes sewage and greywater from a building. It is often attached to the exterior of a building (although it may be fitted internally) and connects the subterranean drainage system to a point just above the level of the roof gutter.
Soil vent pipes allow the removal of waste from toilets, showers, baths and sinks, while also allowing odours to be released above the building, via a stack vent, at a level that will not cause a nuisance. The pipe’s vents also allow air into the internal drainage system so as to facilitate the process of aerobic sewage digestion, preventing a siphoning affect from occurring, and allowing free flow by gravity.
SVPs must maintain sufficient downward slope along their length to keep liquids and entrained solids flowing freely towards the drain. If a downward slope is not possible, a collection pit with a ‘sewage ejector’ pump can be installed.
Approved document H: Drainage and waste disposal requires that the foot of a discharge stack should have as large a radius as possible, and not less than 200 mm at the centre line. Offsets should be avoided in the wet section of the stack. Ventilating pipes should finish at least 900 mm above any opening within 3 m and should be finished with a wire cage or other perforated cover.
 Related articles on Designing Buildings Wiki
Featured articles and news
Developing test methods for video flame/smoke detectors
Waiting for a new deal ...but will funding materialise?
Our servers have reached another milestone. Why not write an article and be seen by our 6.5 million users.
RSHP celebrates competition win in Paris.
All about approved inspectors.
Whilst apparently confusing, German conservation is actually not that different.
The rise and fall of council housing. Book review.
Drivers of change in global heating markets.
11 interesting facts about the use and nature of the material.
Will politicians ultimately fail to tackle Britain's structural challenges?
How self-certification can save time and money.