Double-walled pipe 9116- Part II Double-walled pipe 9116- Part I KOMO test method 7669- Drainage mesh pipe Piping systems for water supply and drainage applications under pressure buried in UPVC soil and above ground. (Soil buried piping systems for wastewater and gravity drainage applications - rigid piping (PVC-U) DIN 1187 Double-walled pipe 9116 - Part Three