Deep main pipelines inside the house

Hello,

today the base slab was concreted here. What I noticed - unfortunately only late - is that the main pipes lie very superficially under the slab and have been led outside the house (about 15cm below the sand). As far as I know, the pipes must be located outside the building in the frost-free zone. How is this handled inside the house?

That is correct. Supply and disposal lines are laid at different depths and trench widths depending on the type. For the installation of wastewater pipes inside and outside buildings, the DIN standards DIN EN 752 / 1610 / 12056-5 apply.

Pipes outside buildings must generally be laid frost-free, with a cover of 80-120 cm (varies regionally according to the frost zone) - see appendix. Inside buildings, a cover of the pipe crown with at least 10 cm of fill sand up to the underside of the floor slab may be sufficient if the rooms are frost-free. This must be decided by the responsible site manager/architect.

Thank you for your answer wpic. Now, however, the drain pipe passes through the foundation to the outside at a depth of about 10-15cm. How do you arrive at 80-120cm, due to the slope? Won't the shallower part of the pipe outside the house freeze later, or does it have to be insulated?