- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 02 Sep 2020
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
A guide to daylight design for commercial buildings.
Smart mapping approaches for building better infrastructure.
The importance of emergency planning.
Eight forms of resource optimisation.
CIOB responds to Chancellor Sunak's announcement on jobs and the economy.
Revised guide to competition rules available.
Brick slip soffit systems and intricate brick features.
An innovative engineering approach could have had tragic consequence for NYC.
Some secrets behind how canals work.
Breaking down possible steps of pre-contract management.
ICE event includes comments from Welsh Government Minister Julie James.
Designing Buildings Wiki becomes the world's first website to adopt the new knowledge standard.