CEN/TS 1046:2021

Thermoplastics piping and ducting systems - Outside the building structures for gravity and pressurised systems - Trench installation

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).

Thermoplastische Kunststoff-Rohrleitungs- und Schutzrohr-Systeme - Systeme außerhalb der Gebäudestruktur zum Transport von Wasser oder Abwasser - Verfahren zur unterirdischen Verlegung

Systèmes de canalisations et de gaines en matières thermoplastiques - Système d'adduction d'eau ou d'assainissement à l'extérieur de la structure des bâtiments - Pratiques pour la pose en enterrée

Cevni in kanalski sistemi iz plastomernih materialov - Sistemi zunaj stavb za transport vode in odpadne vode - Postopki za vgradnjo pod zemljo

General Information

• Status: Published
• Publication Date: 25-May-2021
• ICS: 23.040.01 - Pipeline components and pipelines in general
• ICS: 23.040.05 - Pipeline and its parts for external sewage systems
• ICS: 23.040.20 - Plastics pipes
• ICS: 23.040.45 - Plastics fittings
• ICS: 93.030 - External sewage systems
• Technical Committee: CEN/TC 155 - Plastics piping systems and ducting systems
• Drafting Committee: CEN/TC 155/WG 1 - Installation outside building structures of flexible piping systems
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 26-May-2021
• Completion Date: 26-May-2021
• Ref Project: SIST-TS CEN/TS 1046:2021 - Thermoplastics piping and ducting systems - Outside the building structures for gravity and pressurised systems - Trench installation

Relations

• Replaces: CEN/TR 1046:2013 - Thermoplastics piping and ducting systems - Systems outside building structures for the conveyance of water or sewage - Practices for underground installation
• Effective Date: 02-Jun-2021

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TS CEN/TS 1046:2021
01-julij-2021
Nadomešča:
SIST-TP CEN/TR 1046:2014
Cevni in kanalski sistemi iz plastomernih materialov - Sistemi zunaj stavb za
transport vode in odpadne vode - Postopki za vgradnjo pod zemljo

Thermoplastics piping and ducting systems - Outside the building structures for gravity

and pressurised systems - Trench installation
Thermoplastische Kunststoff-Rohrleitungs- und Schutzrohr-Systeme - Systeme
außerhalb der Gebäudestruktur zum Transport von Wasser oder Abwasser - Verfahren
zur unterirdischen Verlegung
Systèmes de canalisations et de gaines en matières thermoplastiques - Système

d'adduction d'eau ou d'assainissement à l'extérieur de la structure des bâtiments -

Pratiques pour la pose en enterrée
Ta slovenski standard je istoveten z: CEN/TS 1046:2021
ICS:
23.040.03 Cevovodi za zunanje sisteme Pipeline and its parts for
transporta vode in njihovi deli external water conveyance
systems
93.025 Zunanji sistemi za prevajanje External water conveyance
vode systems
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
SIST-TS CEN/TS 1046:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TS CEN/TS 1046:2021
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SIST-TS CEN/TS 1046:2021
CEN/TS 1046
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
May 2021
TECHNISCHE SPEZIFIKATION
ICS 23.040.45; 93.030; 23.040.05; 23.040.20 Supersedes CEN/TR 1046:2013
English Version
Thermoplastics piping and ducting systems - Outside the
building structures for gravity and pressurised systems -
Trench installation

Systèmes de canalisations et de gaines en matières Thermoplastische Kunststoff-Rohrleitungs- und

thermoplastiques - Système d'adduction d'eau ou Schutzrohr-Systeme - Systeme außerhalb der

d'assainissement à l'extérieur de la structure des Gebäudestruktur zum Transport von Wasser oder

bâtiments - Pratiques pour la pose en enterrée Abwasser - Verfahren zur unterirdischen Verlegung

This Technical Specification (CEN/TS) was approved by CEN on 12 April 2021 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to

submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS

available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in

parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 1046:2021 E

worldwide for CEN national Members.
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CEN/TS 1046:2021 (E)
Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Symbols .............................................................................................................................................................. 6

5 Abbreviations ................................................................................................................................................... 7

6 Delivery, handling, transportation and storage on site .................................................................... 7

6.1 General................................................................................................................................................................ 7

6.2 Handling and transportation ...................................................................................................................... 7

6.3 Storage of pipes ............................................................................................................................................... 8

6.4 Storage of fittings and other products..................................................................................................... 8

7 Installation ........................................................................................................................................................ 9

7.1 General................................................................................................................................................................ 9

7.2 Trench construction ...................................................................................................................................... 9

7.2.1 General................................................................................................................................................................ 9

7.2.2 Trench width .................................................................................................................................................... 9

7.2.3 Trench depth .................................................................................................................................................. 11

7.2.4 Trench bottom and bedding ..................................................................................................................... 11

7.2.5 Jointing preparation .................................................................................................................................... 16

7.2.6 Installation, procedures and control ..................................................................................................... 16

7.2.7 Backfilling ........................................................................................................................................................ 20

8 Plastic manholes, inspection chambers and gullies ......................................................................... 24

9 Side connections ............................................................................................................................................ 24

10 Bending under ambient temperatures ................................................................................................. 25

11 Waste treatment ............................................................................................................................................ 25

12 Inspection and testing ................................................................................................................................. 25

12.1 Inspection after installation ..................................................................................................................... 25

12.2 Tightness and pressure testing ................................................................................................................ 25

12.3 Permissible deformation ........................................................................................................................... 26

Annex A (informative) Classification of soils ................................................................................................... 27

Bibliography ................................................................................................................................................................. 30

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CEN/TS 1046:2021 (E)
European foreword

This document (CEN/TS 1046:2021) has been prepared by Technical Committee CEN/TC 155 “Plastics

piping systems and ducting systems”, the secretariat of which is held by NEN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes CEN/TR 1046:2013.

This document is changed fundamentally by taking out design topics and topics already dealt with in

EN 1610 and EN 805. The lay-out was changed and the pressure systems are described more in detail.

According to the CEN/CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
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CEN/TS 1046:2021 (E)
Introduction

This document contains guidance for installation procedures for thermoplastics piping systems and

their components intended to be used below ground for pressure and non-pressure applications

outside building structures. This document is intended to be used in conjunction with general standards

for installation recommendations, for example those issued by CEN/TC 164 “Water supply” and

CEN/TC 165 “Waste water engineering” as stated in EN 805 and EN 1610 respectively.

NOTE 1 Guidelines for installation of pipelines made out of thermosetting materials can be found in the ISO/TS

10465 series [23].

This document is based on the results from research with full-scale trials undertaken by the

thermoplastics pipes industry and expressed in CEN/TS 15223.

This document is a guidance document only. It provides a set of general guidelines which gives best

practices for underground installation of thermoplastics piping and ducting systems outside building

structures.

This document includes recommendations for the pipe surround and backfilling procedures but not

road base and road sub-base details. Attention is drawn to any national regulations which may cover

these or other aspects of the installation.

This document does not cover matters relating to renovation of existing pipeline systems using lining

techniques, or replacement of existing pipeline systems using trenchless techniques.

NOTE 2 Guidelines for installation of lining techniques can be found in the EN 12889 series

This document is intended to be used by authorities, design engineers, installation contractors and

manufacturers.

In this document, much of the guidance is expressed as requirements, e.g. by use of “shall” or by

instructions in the imperative. It is strongly recommended that these be followed whenever applicable.

Other guidance is presented for consideration as a matter of judgement in each case, e.g. by use of

“should”.
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CEN/TS 1046:2021 (E)
1 Scope

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 there will be applicable manufacturer's

instructions.

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).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

EN 805, Water supply - Requirements for systems and components outside buildings
EN 1610:2015, Construction and testing of drains and sewers
3 Terms and definitions

For the purposes of this document, the following terms and definitions apply in addition to EN 1610.

3.1
deformation
change in the true shape of the cross-section
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CEN/TS 1046:2021 (E)
3.2
deflection
change of direction
3.3
trench
excavation of the soil for the underground embedment of the pipeline

Note 1 to entry: See Figure 1 for an illustration of the meaning and limits of the terms used in this document.

Key
1 surface 10 depth of cover
2 bottom of road or railway construction, if any 11 depth of bedding
3 trench walls 12 depth of embedment
4 main backfill 13 trench depth
5 initial backfill, c a thickness of lower bedding
6 sidefill b thickness of upper bedding
7 upper bedding, b c thickness of initial backfill
8 lower bedding, a OD outside diameter (vertical)
9 trench bottom x/2 working space
Note 2 to entry: For minimum values of a and c, see 7.2.4.1.
Figure 1 — Terminology trench cross-section
4 Symbols
For the purposes of this document, the following symbols apply:
x w -OD
min

x/2 horizontal clearance between the pipe or fitting and the trench sidewall or an

adjacent pipe or fitting
d (mean) external diameter of a pipe
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CEN/TS 1046:2021 (E)
e pipe wall thickness
w minimum trench width
min
M compaction classification: Moderate
N compaction classification: Not
W compaction classification: Well
β the angle of unsupported trench side measured to the horizontal
5 Abbreviations
For the purposes of this document, the following abbreviations apply:
DN/OD nominal outside diameter of a pipe and associated fittings;
OD outside diameter
OD horizontal outside diameter
vertical outside diameter
DN nominal diameter
SN stiffness number or classification
SDR standard dimension ratio
PN nominal pressure
UV ultraviolet
STP system test pressure
6 Delivery, handling, transportation and storage on site
6.1 General

Correct delivery, handling, transportation and storage is a pre-condition for good installation and the

performance of the system.

Products shall be inspected on delivery to ensure that they are marked and packed (e.g. plugged pipe

ends for drinking water) in compliance with the specification (e.g. product standard, SN, SDR, PN,

DN/OD and material designation). Non-compliant products should not be accepted and appropriate

measures should be taken to avoid the use of these products.

Products shall be examined both on delivery and immediately prior to installation to ensure that they

are free from damage, assessed in accordance with the relevant Product Standard. Damaged products

should be marked and appropriate measures should be taken to avoid the use of these products.

6.2 Handling and transportation

Regarding handling and transportation the following should be taken into account:

— any handling or transportation instructions from the manufacturer should be complied with;

— pipes may be supplied in straight lengths or coiled forms (either free standing or on drums).

Care should be taken when de-coiling pipes, as considerable forces can be released;

— secure the products or product bundles effectively before transporting on the site;

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CEN/TS 1046:2021 (E)
— when transporting socketed pipes, loading of the sockets should be avoided;
— when handling products care should be taken to prevent damage;
NOTE Avoid lifting equipment with sharp edges.

— the impact resistance of thermoplastics products is reduced at low temperatures. Under these

conditions, take more care during handling. Where cold conditions are expected, the advice of the

manufacturer should be followed.
6.3 Storage of pipes
Regarding storage of pipes the following should be taken into account:
— manufacturers' instructions should be followed;

— when pipes or coils are stored on site in stacks, the manufacturer's advice regarding correct

practice should be followed;

— stack the pipes or coils on reasonably flat surfaces free from sharp objects, stones or projections

in order to avoid localized deformation or damage to the pipes;
— respect the maximum stacking height as defined by the manufacturer;

— do not place products in close proximity to fuels, solvents, oils, greases, paints and/or heat

sources;

— storage in direct sunlight for long periods and/or high temperatures could cause deformations

which could affect the jointing negatively. To avoid this risk, the following precautions are

recommended:
— limit the height of the stacks of pipes;
— shield the stacks of pipes from continuous and direct sunlight;
— arrange to allow the free passage of air around the pipes.

— pipes have a restriction for storage under direct UV radiation. Respect therefor the manufacturer's

storage instructions.

NOTE Fading of the colour is not necessarily affecting the mechanical properties of products.

6.4 Storage of fittings and other products

Regarding storage of fittings and other products the following should be taken into account:

— manufacturer’s instructions should be followed;

— the original packaging should be kept intact if products are supplied in packaging, the

packaging should be removed as late as possible prior to installation;
— products should be protected from environmental influences;
— it's recommended to store the products below +50 °C;
— the products should be protected from direct exposure to sunlight;
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CEN/TS 1046:2021 (E)

— the products should be protected from other heavy energy radiation from devises.

7 Installation
7.1 General

Deformation in a plastic piping system (pressure and non-pressure) is significantly influenced by the

quality of the installation, especially the degree of compaction and choice of bedding material. The use

of the installation procedures detailed in this document will minimize the deformation. A more detailed

description of this behaviour and its limitations is given in CEN/TS 15223:2017, 7.2 and 7.3.

The most commonly used practice for the installation of thermoplastics systems is to surround the pipe

(see Figure 1, key 5+6+7+8) with one type of bedding material.
7.2 Trench construction
7.2.1 General
Operations in open trenches are carried out in potentially hazardous conditions.

Where appropriate apply shore, sheet, brace, slope or other supports of the trench walls to protect any

person in the trench. When the trench is occupied take precautions:
— to prevent objects from falling into the trench;

— to prevent collapse caused by the position or movements of adjacent machinery or equipment.

Excavated material should be deposited at a distance of not less than 0,5 m from the edge of the trench,

and the proximity and height of the excavated material (spoil bank) should not be allowed to endanger

the stability of the excavation.

When trench supports such as sheet piling or similar is used, the pipe support and any compacted soil

around the pipe shall be maintained throughout installation. Ensure that sheeting is sufficiently tight to

prevent washing soil out of the trench wall from behind the sheeting.

If trench supports are removed after the trench has been backfilled, care should be taken to not disturb

the compaction of the primary backfill material around the pipe.

If it is not possible to remove trench supports without disturbing the trench compaction, it is

recommended to keep the sheeting in place to prevent loss of support of foundation and embedment

materials. Vertical and horizontal braces should be left in place. Top cross bracing may need to be

installed if the top of the sheeting is cut off to accommodate for landscaping. Sheeting that is to be left in

the trench shall be constructed of materials that will not corrode or rot, resulting in a loss of support for

the pipe.
7.2.2 Trench width

The width of the trench at the springline of the pipe should not be greater than necessary to provide

adequate room for jointing the pipe in the trench and compacting the pipe zone backfill at the haunches.

The minimum trench width (see Figure 1 and 2) is given in Table 1 and Table 2.
NOTE Table 1 is in compliance with the requirements of EN 1610.
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CEN/TS 1046:2021 (E)

Table 1 — Minimum trench width depending on the nominal diameter (DN) of the pipe

Minimum trench width (OD + x)
Nominal size (DN)
Unsupported trench
Supported trench
β ˃60° β ≤ 60°
OD + 0,40 OD + 0,40
DN ≤ 225
h h
OD + 0,50 OD + 0,50 OD + 0,40
225 < DN ≤ 350
h h h
OD + 0,70 OD + 0,70 OD + 0,40
350 < DN ≤ 700
h h h
OD + 0,85 OD + 0,85 OD + 0,40
700 < DN ≤ 1 200
h h h
OD + 1,00 OD + 1,00 OD + 0,40
DN ˃ 1 200
h h h
See Figure 2.
Key
w minimum trench width
min
a thickness of lower bedding
b thickness of upper bedding
x/2 working space next to pipe
β angle of unsupported trench
Figure 2 — Working space next to the pipe and angle of unsupported trench
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CEN/TS 1046:2021 (E)
Table 2 — Minimum trench width depending on the trench depth
Minimum trench width
Trench depth (Td)
Td < 1,00 No minimum width required
1,00 ≤ Td ≤ 1,75 0,80
1,75 < Td ≤ 4,00 0,90
Td ˃ 4,00 1,00

Stability shall be ensured either by means of a trench support system, by battering the trench

sides to a stable slope which can be maintained during the works or by other suitable means. The

maximum depth of unsupported trenches with vertical trench walls shall be limited according to

national regulations and in any case less than 1,4 m.

Wider trenches may be necessary for installations involving, e.g. relatively deep burial or unstable

native soils. Narrower trenches may be used when the system design permits or access by persons is

not required.

Parallel piping systems laid within a common trench shall be spaced sufficiently far apart to allow

compaction equipment, if used, to compact the pipe zone backfill material between the pipes.

A clearance of at least 150 mm greater than the width of the widest piece of compaction equipment

used is considered as a practical clearance between the pipes.
7.2.3 Trench depth

Determine the trench depth by the pipeline design, intended service, pipe properties, size of pipe and

local conditions such as the properties of soil and combination of static and dynamic loading.

In general, care should be taken that the depth of cover above the crown of the pipe for pipes passing

under traffic areas should usually be a minimum of 600 mm, although shallower depths may be used

when the installation is designed accordingly.

When determining the trench depth, allowance for a suitable bedding should be incorporated.

Take care to ensure that the burial depth is sufficient to prevent the conveyed fluids from being affected

by frost.

Sufficient cover or other suitable constructions should be provided to prevent accidental pipe flotation

in potentially high ground water areas.

It is generally recommended not to dig the trench too far in advance of pipe laying and to backfill as

soon as possible after pipe laying.

In frost conditions, it may be necessary to protect the trench bottom so that frozen layers are not left

under the pipe.
7.2.4 Trench bottom and bedding
7.2.4.1 General

A pipe requires uniform support for the whole of its length and this is provided by the bedding layer. To

provide this uniform support, the bedding layer should in average have a minimum thickness of

100 mm and on individual places not less than 50 mm.

The material used shall be granular, such as gravel, sand or crushed rock, and shall conform to 7.2.7.3

and Annex A.
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CEN/TS 1046:2021 (E)

The bedding material should be spread evenly across the full width of the trench and levelled to the

gradient of the pipeline and, if necessary, compacted.
Two bedding constructions can be distinguished:
— bedding construction type 1;
— bedding construction type 2.

Bedding construction type 1 (Figure 3) may be used in all types of embedment, providing support for

the pipes over their whole barrel length, using the layer thickness requirements for a and b. This

includes any size and shape of pipes e.g. circular, non-circular, flat based. Unless specified otherwise,

the thickness of the lower bedding a, measured under the barrel, shall not be less than:

— 100 mm in usual soil conditions;
— 150 mm in rock or hard soil conditions.
The thickness b of upper bedding shall be as specified in the structural design.

Bedding construction type 2 (Figure 4) may be used in uniform relatively soft fine-grained soil

providing support for the pipes over their whole barrel length. Pipes may be laid directly on the shaped,

trimmed bottom of the trench. The thickness b of upper bedding shall be as specified in the structural

design.
Key
a thickness of lower bedding
b thickness of upper bedding
OD outside diameter (vertical)
Figure 3 — Bedding construction type 1
Key
b thickness of upper bedding
OD outside diameter (vertical)
Figure 4 — Bedding construction type 2
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CEN/TS 1046:2021 (E)

Where necessary, holes in the lower bedding or trench bottom shall be provided to allow sufficient

space for proper assembly of the joints and products to prevent the pipe from resting on the joint or

product. The hole should not be larger than necessary to accomplish proper assembly.

The upper and lower-bedding at the trench (see Figure 1) shall be continuous, uniform and free of

particles greater than those specified in Table 3 for the applicable pipe size.
Over-excavation of the trench bottom is required, when:
— rock, cobbles or hardpan are encountered;

— quick sands or similar soils, organic soils or soils are present that exhibit a volume change with a

change in moisture content may be encountered in the bottom of the trench.

Each such situation shall be evaluated on a case-by-case basis during construction to determine the

extent of over-excavation and the type of foundation material to be used.

Where over-excavation is performed, including accidental over-excavation during construction, it is

recommended that the material for the foundation zone shall be the same as for the bedding zone and

shall be compacted to class W (see 7.2.7.3).
Compact the foundation material uniformly in accordance with 7.2.7.4.

During the installation work, trenches shall be kept free of water, e.g. rainwater, leachate, spring water,

ground water or water leakage from pipelines. The mode of drainage should not affect the pipe zone

and the pipeline.

Precautions shall be taken to prevent the erosion of fine material during water control. The influence of

drainage measures on groundwater movement and the stability of the surrounding soil shall be

considered.
The water level should
...

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 1046:2021
01-februar-2021
Cevni in kanalski sistemi iz plastomernih materialov - Sistemi zunaj stavb za
transport vode in odpadne vode - Postopki za vgradnjo pod zemljo

Thermoplastics piping and ducting systems - Outside the building structures for gravity

and pressurised systems - Trench installation
Thermoplastische Kunststoff-Rohrleitungs- und Schutzrohr-Systeme - Systeme
außerhalb der Gebäudestruktur zum Transport von Wasser oder Abwasser - Verfahren
zur unterirdischen Verlegung
Systèmes de canalisations et de gaines en matières thermoplastiques - Système

d'adduction d'eau ou d'assainissement à l'extérieur de la structure des bâtiments -

Pratiques pour la pose en enterrée
Ta slovenski standard je istoveten z: FprCEN/TS 1046
ICS:
23.040.03 Cevovodi za zunanje sisteme Pipeline and its parts for
transporta vode in njihovi deli external water conveyance
systems
93.025 Zunanji sistemi za prevajanje External water conveyance
vode systems
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
kSIST-TS FprCEN/TS 1046:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TS FprCEN/TS 1046:2021
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kSIST-TS FprCEN/TS 1046:2021
FINAL DRAFT
TECHNICAL SPECIFICATION
FprCEN/TS 1046
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2020
ICS 23.040.01; 93.030 Will supersede CEN/TR 1046:2013
English Version
Thermoplastics piping and ducting systems - Outside the
building structures for gravity and pressurised systems -
Trench installation

Systèmes de canalisations et de gaines en matières Thermoplastische Kunststoff-Rohrleitungs- und

thermoplastiques - Système d'adduction d'eau ou Schutzrohr-Systeme - Systeme außerhalb der

d'assainissement à l'extérieur de la structure des Gebäudestruktur zum Transport von Wasser oder

bâtiments - Pratiques pour la pose en enterrée Abwasser - Verfahren zur unterirdischen Verlegung

This draft Technical Specification is submitted to CEN members for Vote. It has been drawn up by the Technical Committee

CEN/TC 155.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a Technical Specification. It is distributed for review and comments. It is subject to change

without notice and shall not be referred to as a Technical Specification.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 1046:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ...................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions ................................................................................................................................... 5

4 Symbols .............................................................................................................................................................. 6

5 Abbreviations ................................................................................................................................................... 7

6 Delivery, handling, transportation and storage on site .................................................................... 7

6.1 General................................................................................................................................................................ 7

6.2 Handling and transportation ...................................................................................................................... 7

6.3 Storage of pipes ............................................................................................................................................... 8

6.4 Storage of fittings and other products..................................................................................................... 8

7 Installation ........................................................................................................................................................ 9

7.1 General................................................................................................................................................................ 9

7.2 Trench construction ...................................................................................................................................... 9

7.2.1 General................................................................................................................................................................ 9

7.2.2 Trench width .................................................................................................................................................... 9

7.2.3 Trench depth .................................................................................................................................................. 11

7.2.4 Trench bottom and bedding ..................................................................................................................... 11

7.2.5 Jointing preparation .................................................................................................................................... 16

7.2.6 Installation, procedures and control ..................................................................................................... 16

7.2.7 Backfilling ........................................................................................................................................................ 20

8 Plastic manholes, inspection chambers and gullies ......................................................................... 24

9 Side connections ............................................................................................................................................ 24

10 Bending under ambient temperatures ................................................................................................. 25

11 Waste treatment ............................................................................................................................................ 25

12 Inspection and testing ................................................................................................................................. 25

12.1 Inspection after installation ..................................................................................................................... 25

12.2 Tightness and pressure testing ................................................................................................................ 25

12.3 Permissible deformation ........................................................................................................................... 26

Annex A (informative) Classification of soils ..................................................................................................... 27

A.1 General.............................................................................................................................................................. 27

Bibliography ................................................................................................................................................................. 30

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European foreword

This document (FprCEN/TS 1046:2020) has been prepared by Technical Committee CEN/TC 155

“Plastics piping systems and ducting systems”, the secretariat of which is held by NEN.

This document is currently submitted to the Vote on TS.
This document will supersede CEN/TR 1046:2014.

This document is changed fundamentally by taking out design topics and topics already dealt with in

EN 1610 and EN 805. The lay-out was changed and the pressure systems are described more in detail.

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Introduction

This Document contains guidance for installation procedures for thermoplastics piping systems and

their components intended to be used below ground for pressure and non-pressure applications

outside building structures. This document is intended to be used in conjunction with general standards

for installation recommendations, for example those issued by CEN/TC 164 “Water supply” and

CEN/TC 165 “Waste water engineering” as stated in EN 805 and EN 1610 respectively.

NOTE Guidelines for installation of pipelines made out of thermosetting materials can be found in the ISO/TS

10465 series [23].

This Document is based on the results from research with full-scale trials undertaken by the

thermoplastics pipes industry and expressed in CEN/TS 15223.

This Document is a guidance document only. It provides a set of general guidelines which gives best

practices for underground installation of thermoplastics piping and ducting systems outside building

structures.

This Document includes recommendations for the pipe surround and backfilling procedures but not

road base and road sub-base details. Attention is drawn to any national regulations which may cover

these or other aspects of the installation.

This Document does not cover matters relating to renovation of existing pipeline systems using lining

techniques, or replacement of existing pipeline systems using trenchless techniques.

NOTE Guidelines for installation of lining techniques can be found in the EN 12889 series

This Document is intended to be used by authorities, design engineers, installation contractors and

manufacturers.

In this Document, much of the guidance is expressed as requirements, e.g. by use of “shall” or by

instructions in the imperative. It is strongly recommended that these be followed whenever applicable.

Other guidance is presented for consideration as a matter of judgement in each case, e.g. by use of

“should”.
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1 Scope

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 there will be applicable manufacturer's

instructions.

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).
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

EN 805, Water supply — Requirements for systems and components outside buildings
EN 1610:2015, Construction and testing of drains and sewers
3 Terms and definitions

For the purposes of this document, the following terms and definitions apply in addition to EN 1610.

3.1
deformation
change in the true shape of the cross-section
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3.2
deflection
change of direction
3.3
trench
excavation of the soil for the underground embedment of the pipeline

Note 1 to entry: See Figure 1 for an illustration of the meaning and limits of the terms used in this document.

Key
1 surface 10 depth of cover
2 bottom of road or railway construction, if any 11 depth of bedding
3 trench walls 12 depth of embedment
4 main backfill 13 trench depth
5 initial backfill, c a thickness of lower bedding
6 sidefill b thickness of upper bedding
7 upper bedding, b c thickness of initial backfill
8 lower bedding, a OD outside diameter (vertical)
9 trench bottom x/2 working space
Note 1 to entry: For minimum values of a and c, see 7.2.4.1.
Figure 1 — Terminology trench cross-section
4 Symbols
For the purposes of this document, the following symbols apply:
x w -OD
min

x/2 horizontal clearance between the pipe or fitting and the trench sidewall or an

adjacent pipe or fitting
d (mean) external diameter of a pipe
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e pipe wall thickness
w minimum trench width
min
M compaction classification: Moderate
N compaction classification: Not
W compaction classification: Well
β the angle of unsupported trench side measured to the horizontal
5 Abbreviations
For the purposes of this document, the following abbreviations apply:
DN/OD nominal outside diameter of a pipe and associated fittings;
OD outside diameter
OD Horizontal outside diameter
outside diameter (vertical)
DN nominal diameter
SN stiffness number or classification
SDR standard dimension ratio
PN nominal pressure
UV ultraviolet
STP system test pressure
6 Delivery, handling, transportation and storage on site
6.1 General

Correct delivery, handling, transportation and storage is a pre-condition for good installation and the

performance of the system.

Products shall be inspected on delivery to ensure that they are marked and packed (e.g. plugged pipe

ends for drinking water) in compliance with the specification (e.g. product standard, SN, SDR, PN,

DN/OD and material designation). Non-compliant products should not be accepted and appropriate

measures should be taken to avoid the use of these products.

Products shall be examined both on delivery and immediately prior to installation to ensure that they

are free from damage, assessed in accordance with the relevant Product Standard. Damaged products

should be marked and appropriate measures should be taken to avoid the use of these products.

6.2 Handling and transportation

Regarding handling and transportation the following should be taken into account:

— any handling or transportation instructions from the manufacturer should be complied with;

— pipes may be supplied in straight lengths or coiled forms (either free standing or on drums).

Care should be taken when de-coiling pipes, as considerable forces can be released;

— secure the products or product bundles effectively before transporting on the site;

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— when transporting socketed pipes, loading of the sockets should be avoided;
— when handling products care should be taken to prevent damage;
NOTE Avoid lifting equipment with sharp edges.

— the impact resistance of thermoplastics products is reduced at low temperatures. Under these

conditions, take more care during handling. Where cold conditions are expected, the advice of the

manufacturer should be followed.
6.3 Storage of pipes
Regarding storage of pipes the following should be taken into account:
— manufacturers' instructions should be followed;

— when pipes or coils are stored on site in stacks, the manufacturer's advice regarding correct

practice should be followed;

— stack the pipes or coils on reasonably flat surfaces free from sharp objects, stones or projections

in order to avoid localized deformation or damage to the pipes;
— respect the maximum stacking height as defined by the manufacturer;

— do not place products in close proximity to fuels, solvents, oils, greases, paints and/or heat

sources;

— storage in direct sunlight for long periods and/or high temperatures could cause deformations

which could affect the jointing negatively. To avoid this risk, the following precautions are

recommended:
— limit the height of the stacks of pipes;
— shield the stacks of pipes from continuous and direct sunlight;
— arrange to allow the free passage of air around the pipes.

— pipes have a restriction for storage under direct UV radiation. Respect therefor the manufacturer's

storage instructions.

NOTE Fading of the colour is not necessarily affecting the mechanical properties of products.

6.4 Storage of fittings and other products

Regarding storage of fittings and other products the following should be taken into account:

— manufacturer’s instructions should be followed;

— the original packaging should be kept intact if products are supplied in packaging, the

packaging should be removed as late as possible prior to installation;
— products should be protected from environmental influences;
— it's recommended to store the products below +50 °C;
— the products should be protected from direct exposure to sunlight;
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— the products should be protected from other heavy energy radiation from devises.

7 Installation
7.1 General

Deformation in a plastic piping system (pressure and non-pressure) is significantly influenced by the

quality of the installation, especially the degree of compaction and choice of bedding material. The use

of the installation procedures detailed in this document will minimize the deformation. A more detailed

description of this behaviour and its limitations is given in CEN/TS 15223:2017, 7.2 and 7.3.

The most commonly used practice for the installation of thermoplastics systems is to surround the pipe

(see Figure 1, key 5+6+7+8) with one type of bedding material.
7.2 Trench construction
7.2.1 General
Operations in open trenches are carried out in potentially hazardous conditions.

Where appropriate apply shore, sheet, brace, slope or other supports of the trench walls to protect any

person in the trench. When the trench is occupied take precautions:
— to prevent objects from falling into the trench;

— to prevent collapse caused by the position or movements of adjacent machinery or equipment.

Excavated material should be deposited at a distance of not less than 0,5 m from the edge of the trench,

and the proximity and height of the excavated material (spoil bank) should not be allowed to endanger

the stability of the excavation.

When trench supports such as sheet piling or similar is used, the pipe support and any compacted soil

around the pipe shall be maintained throughout installation. Ensure that sheeting is sufficiently tight to

prevent washing soil out of the trench wall from behind the sheeting.

If trench supports are removed after the trench has been backfilled, care should be taken to not disturb

the compaction of the primary backfill material around the pipe.

If it is not possible to remove trench supports without disturbing the trench compaction, it is

recommended to keep the sheeting in place to prevent loss of support of foundation and embedment

materials. Vertical and horizontal braces should be left in place. Top cross bracing may need to be

installed if the top of the sheeting is cut off to accommodate for landscaping. Sheeting that is to be left in

the trench shall be constructed of materials that will not corrode or rot, resulting in a loss of support for

the pipe.
7.2.2 Trench width

The width of the trench at the springline of the pipe should not be greater than necessary to provide

adequate room for jointing the pipe in the trench and compacting the pipe zone backfill at the haunches.

The minimum trench width (see Figure 1 and 2) is given in Table 1 and Table 2.
NOTE Table 1 is in compliance with the requirements of EN 1610.
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Table 1 — Minimum trench width depending on the nominal diameter (DN) of the pipe

Minimum trench width (OD + x)
Nominal size (DN)
Unsupported trench
Supported trench
β ˃60° β ≤ 60°
OD + 0,40 OD + 0,40
DN ≤ 225
h h
OD + 0,50 OD + 0,50 OD + 0,40
225 < DN ≤ 350
h h h
OD + 0,70 OD + 0,70 OD + 0,40
350 < DN ≤ 700
h h h
OD + 0,85 OD + 0,85 OD + 0,40
700 < DN ≤ 1 200
h h h
OD + 1,00 OD + 1,00 OD + 0,40
DN ˃ 1 200
h h h
See Figure 2.
Key
w minimum trench width
min
a thickness of lower bedding
b thickness of upper bedding
x/2 working space next to pipe
β angle of unsupported trench
Figure 2 — Working space next to the pipe and angle of unsupported trench
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Table 2 — Minimum trench width depending on the trench depth
Minimum trench width
Trench depth (Td)
Td < 1,00 No minimum width required
1,00 ≤ Td ≤ 1,75 0,80
1,75 < Td ≤ 4,00 0,90
Td ˃ 4,00 1,00

Stability shall be ensured either by means of a trench support system, by battering the trench

sides to a stable slope which can be maintained during the works or by other suitable means. The

maximum depth of unsupported trenches with vertical trench walls shall be limited according to

national regulations and in any case less than 1,4 m.

Wider trenches may be necessary for installations involving, e.g. relatively deep burial or unstable

native soils. Narrower trenches may be used when the system design permits or access by persons is

not required.

Parallel piping systems laid within a common trench shall be spaced sufficiently far apart to allow

compaction equipment, if used, to compact the pipe zone backfill material between the pipes.

A clearance of at least 150 mm greater than the width of the widest piece of compaction equipment

used is considered as a practical clearance between the pipes.
7.2.3 Trench depth

Determine the trench depth by the pipeline design, intended service, pipe properties, size of pipe and

local conditions such as the properties of soil and combination of static and dynamic loading.

In general, care should be taken that the depth of cover above the crown of the pipe for pipes passing

under traffic areas should usually be a minimum of 600 mm, although shallower depths may be used

when the installation is designed accordingly.

When determining the trench depth, allowance for a suitable bedding should be incorporated.

Take care to ensure that the burial depth is sufficient to prevent the conveyed fluids from being affected

by frost.

Sufficient cover or other suitable constructions should be provided to prevent accidental pipe flotation

in potentially high ground water areas.

It is generally recommended not to dig the trench too far in advance of pipe laying and to backfill as

soon as possible after pipe laying.

In frost conditions, it may be necessary to protect the trench bottom so that frozen layers are not left

under the pipe.
7.2.4 Trench bottom and bedding
7.2.4.1 General

A pipe requires uniform support for the whole of its length and this is provided by the bedding layer. To

provide this uniform support, the bedding layer should in average have a minimum thickness of

100 mm and on individual places not less than 50 mm.

The material used shall be granular, such as gravel, sand or crushed rock, and shall conform to 7.2.7.3

and Annex A.
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The bedding material should be spread evenly across the full width of the trench and levelled to the

gradient of the pipeline and, if necessary, compacted.
Two bedding constructions can be distinguished:
— bedding construction type 1;
— bedding construction type 2.

Bedding construction type 1 (Figure 3) may be used in all types of embedment, providing support for

the pipes over their whole barrel length, using the layer thickness requirements for a and b. This

includes any size and shape of pipes e.g. circular, non-circular, flat based. Unless specified otherwise,

the thickness of the lower bedding a, measured under the barrel, shall not be less than:

— 100 mm in usual soil conditions;
— 150 mm in rock or hard soil conditions.
The thickness b of upper bedding shall be as specified in the structural design.

Bedding construction type 2 (Figure 4) may be used in uniform relatively soft fine-grained soil

providing support for the pipes over their whole barrel length. Pipes may be laid directly on the shaped,

trimmed bottom of the trench. The thickness b of upper bedding shall be as specified in the structural

design.
Key
a thickness of lower bedding
b thickness of upper bedding
OD outside diameter (vertical)
Figure 3 — Bedding construction type 1
Key
b thickness of upper bedding
OD outside diameter (vertical)
Figure 4 — Bedding construction type 2
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Where necessary, holes in the lower bedding or trench bottom shall be provided to allow sufficient

space for proper assembly of the joints and products to prevent the pipe from resting on the joint or

product. The hole should not be larger than necessary to accomplish proper assembly.

The upper and lower-bedding at the trench (see Figure 1) shall be continuous, uniform and free of

particles greater than those specified in Table 3 for the applicable pipe size.
Over-excavation of the trench bottom is required, when:
— rock, cobbles or hardpan are encountered;

— quick sands or similar soils, organic soils or soils are present that exhibit a volume change with a

change in moisture content may be encountered in the bottom of the trench.

Each such situation shall be evaluated on a case-by-case basis during construction to determine the

extent of over-excavation and the type of foundation material to be used.

Where over-excavation is performed, including accidental over-excavation during construction, it is

recommended that the material for the foundation zone shall be the same as for the bedding zone and

shall be compacted to class W (see 7.2.7.3).
Compact the foundation material uniformly in accordance with 7.2.7.4.

During the installation work, trenches shall be kept free of water, e.g. rainwater, leachate, spring water,

ground water or water leakage from pipelines. The mode of drainage should not affect the pipe zone

and the pipeline.

Precautions shall be taken to prevent the erosion of fine material during water control. The influence of

drainage measures on groundwater movement and the stability of the surrounding soil shall be

considered.

The water level should be controlled until the embedment is installed and sufficient backfill has been

placed to prevent flotation of the pipe.

After completion of the drainage measures, all construction drains should be sufficiently closed or

removed.
7.2.4.2 Ground reinforcement

When settlement of the soil can be expected, such as when a pipe passes through a soil transition, the

use of geotextiles as shown in Figure 10 can provide a solution. However, where large-scale soil

movements are anticipated, this solution may not be effective. In such cases, it is recommended to seek

expert advice.
Special conditions which
...