CEN/TS 15223:2017

This Technical Specification covers validated design parameters of buried thermoplastics piping systems for functional and structural design for the following applications:
pressure (excluding piping systems for gaseous fluids and industrial applications);
non-pressure.
The functional design is based on relevant standards and commonly used practices.
Depending on the project parameters, this route for structural design can be
either established by long term experience (within certain limitations),
or calculated according to CEN/TR 1295-2 by using thermoplastic pipe material related properties and design criteria.
NOTE  The route is shown in the flowchart given in Figure 1 in 4.1.
Since in practice precise details of types of soil and installation conditions are not always available at the design stage, the choice of design assumptions is left to the judgement of the designer/specifier. In this connection, this guide can only provide general indications and advice.