CEN/TC 155/WG 1 - Installation outside building structures of flexible piping systems

This document gives the recommended practise for underground open trench installation and commissioning of thermoplastics piping systems to be used for the conveyance of water under pressure (in addition to EN 805) and for the discharge of wastewater under gravity (in addition to EN 1610) .
In the field of non-pressure underground drainage and sewerage this is reflected in the marking of products by application code "U" and "UD":
-   outside the building structure (U);
-   both buried in ground within the building structure (application area code "D") and outside the
building (application area code "UD").
This document covers also installation and/or connections to valves, manholes, inspection chambers, gullies and other ancillary components in piping systems.
NOTE 1   Code of practise for pipelines for gas supply is covered by EN 12007-series [21].
NOTE 2   Recommended practices for installation of plastic piping systems for soil and waste discharge within the building structure is covered by CEN/TR 13801 [12].
NOTE 3   Practices for underground installation of rainwater infiltration and storage attenuation systems are covered by CEN/TR 17179 [13].
NOTE 4   It is assumed that additional recommendations and/or requirements are detailed in the individual product standards.
NOTE 5    If non-plastic components are part of the plastic system the manufacturer's instructions should be taken into account.
Requirements and instructions concerning commissioning of systems can be found in EN 805 and EN 1610 and the relevant national and/or local regulations. This document gives specific additional recommendations for commissioning relevant for plastic piping systems.
Attention is drawn to any relevant local and/or national regulations (e.g. health, safety and hygienic requirements).

This Technical Report is applicable to the installation of rainwater infiltration and storage/attenuation systems under gravity.
This Technical Report covers installations including:
-   reservoirs made by assembled cuboid shaped thermoplastic boxes;
-   integral components;
-   ancillary components (e.g. access provisions and connections);
-   geotextiles and/or geomembranes;
-   embedment and backfill.
These systems are intended for underground use in landscape, pedestrian or vehicular traffic areas and are used outside building structures.
This Technical Report is only applicable to systems containing boxes to create a reservoir where the manufacturer has clearly stated in the installation instructions how the components should be assembled.
This Technical Report is a guidance document. It provides a set of general guidelines which gives best practice for installation.
NOTE 1   It is anticipated that additional recommendations and/or requirements (e.g. design, dimensioning and structural aspects) will be detailed in the relevant standards.
NOTE 2   Attention is drawn to the need to comply with national or local regulations.

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.

This part of EN 1451 specifies the recommended practice for installation of polypropylene (PP) piping systems in the field of soil and waste discharge (low and high temperature) inside buildings (marked with "B") and for soil and waste discharge systems for both inside buildings and buried in ground within the building structure (marked with "BD").

This Technical Report is applicable to the installation of thermoplastics piping systems to be used for the conveyance of water or sewage under gravity and pressure conditions underground. It is intended to be used for pipes of nominal size up to and including DN 1600.
Wherever the term "pipe" is used in this Technical Report, it also serves to cover any "fittings", "ancillary" products and "components" if not otherwise specified.
NOTE 1   This document does not apply to pipelines for gas supply (see EN 12007-2, Gas supply systems pipelines for maximum operating pressure up to and including 16 bars - Part 2: Specific functional recommendations for PE- and MOP up to and including 10 bars).
NOTE 2   It is assumed that additional recommendations and/or requirements are detailed in the individual materials voluntary product standards. Instances where this is expected to apply include those indicated in this Technical Report as follows:
a)   any special transportation requirements (see 5.2);
b)   maximum storage height (see 5.2 and 5.4);
c)   maximum storage period in direct sunlight (see 5.4);
d)   any climatic conditions requiring special storage (see 5.4);
e)   limiting initial and/or long-term deflections (see 6.1.1 and 6.1.2);
f)   information on mole ploughing and boring (see and 6.2), if applicable;
g)   selection of appropriate jointing system (see Clause 7);
h)   recommended radii of curvature for cold bending (see 8.1);
i)   permitted rates of loss of water under test (see 9.2.1);
j)   if applicable the relationship between SDR and stiffness.
Requirements and instructions concerning commissioning of systems can be found in EN 805 and EN 1610 and the relevant national and/or local regulations.