We meet the international standards and they meet us
ISO 161:
Thermoplastics pipe for the transport of fluids, nominal outside diameters and nominal pressure.
DIN 16961:
Thermoplastics pipes and fitting with profiled outer and smooth inner surfaces
EN 13476:
thermoplastics piping system for non-presure underground drainage and sewerage structured wall piping systems.
ATV-A127:
Standerd for the static calculation of drainage sewer and pipelines.
.. and many other standards.