Standpipe (drainage)
The standpipe is used to connect a rain downpipe with a sewer base pipe and is made of a resistant material.
The standpipe should extend half a meter to just over a full meter from the ground. It is more robust against damage than a downpipe made of sheet metal, and sewer base pipes are usually not intended for mechanical loads. A red plastic ( PVC-U ), which is hard and brittle and also not UV- resistant - and is therefore not approved for use above ground, is commonly used for these sewer base pipes .
If the downpipe is protected in a niche and / or the risk is limited to an occasional leaf rake or lawn mower , a height of just under half a meter is sufficient. If, on the other hand, the pipe is open in front of the wall and there is a frequently frequented traffic route, it can make sense to extend the standpipe area up to shoulder height.
If there is a backwater or a blockage in the sewer system, the pressure of the water column acts on the pipes in the floor area. In multi-storey buildings, this can quickly take on a critical value, tearing sheet metal downpipes or causing pipes on the cellar wall to leak. To avoid this, every standpipe should be provided with an overflow , which should be a hand's breadth above the surrounding level. Often these overflow openings are also integrated in a (removable) inspection cover. This inspection opening is recommended when the building is higher or the downpipe is difficult to access, e.g. runs in a wall slot. In the case of a small house and pipes mounted at a distance from the wall, however, the entire downpipe can simply be dismantled for cleaning purposes.
If there is a possibility that parts of plants could get into the downpipe (because trees could protrude over the gutter or because there are green roofs or terraces and no precautions are taken on the gutter), it is advisable to install a leaf collector directly above the standpipe , as it is easily accessible for cleaning there.
Finally, if you intend to use a limited amount of rainwater (in a cistern , rain barrel or through irrigation hoses ), then the best place for a rain collector would be directly on the standpipe, possibly below a downpipe sieve .