SIST ENV 1046:2002

Plastics piping and ducting systems - Systems outside building structures for the conveyance of water or sewage - Practices for installation above and below ground

This prestandard is applicable to the installation of plastics piping systems to be used for the conveyance of water or sewage under gravity and pressure conditions above and below ground. It is intended to be used for pipes of nominal size up to and including DN 3000.
Where in this prestandard the term "pipe" is used then it serves also to cover any "fittings", "ancillary" products and "components".
NOTE 1    It is assumed that additional recommendations and/or requirements are detailed in the individual materials System Standards. Instances where this is expected to apply include those indicated in this prestandard as follows:
a) any special transportation requirements (see 4.2.6);
b) maximum storage height (see 4.4.3 and 4.4.4);
c) maximum storage period in direct sunlight (see 4.4.6);
d) any climatic conditions requiring special storage (see 4.4.7);
e) limiting initial and/or long-term deflections (see 5.1.1 and 5.1.2);
f) information on mole ploughing and boring (see and 5.2), if applicable;
g) longitudinal tensile modulus and strength (see 5.3.1.2);
h) coefficient of thermal linear expansion (see 5.3.2.2 and Annex B);
i) suitability for use in areas exposed to sunlight (see 5.3.3);
j) selection of appropriate jointing system (see clause 6);
k) recommended radii of curvature for cold bending (see 7.1);
l) permitted rates of loss of water under test (see 8.2.1);
m) if applicable the relationship between SDR and stiffness.
NOTE 2   Guidance and instructions concerning commissioning of systems can be found in the standards prepared by CEN/TC 164 and by CEN/TC 165 and the relevant national and/or local regulations.
NOTE 3   Concerning the character of this document see Foreword and Introduction.

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

Diese Vornorm ist anwendbar auf die Verlegung von Kunststoff-Rohrleitungs-Systemen für den ober- und unterirdischen Transport von Wasser und Abwasser unter Gravitations- und Druckbedingungen.  Es ist vorgesehen, sie für Rohre mit Nennweiten bis einschließlich DN 3000 zu verwenden.
Wenn in dieser Vornorm der Begriff "Rohr" verwendet wird, dann gelten damit auch etwaige "Formstücke", "Zubehör" und andere "Komponenten" als abgedeckt.
ANMERKUNG 1   Es wird davon ausgegangen, daß zusätzliche Empfehlungen und/oder Anforderungen in den einzelnen werkstoffbezogenen Systemnormen festgelegt sind.  Fälle, bei denen dieses erwartet wird, sind die Folgenden, auf die in dieser Vornorm hingewiesen wird:
a) jegliche spezielle Anforderungen an den Transport (siehe 4.2.6);
b) maximale Stapelhöhe (siehe 4.4.3 und 4.4.4);
c) maximale Lagerdauer unter direkter Sonneneinstrahlung (siehe 4.4.6);
d) jegliche klimatische Bedingungen, die eine spezielle Lagerung erfordern (siehe 4.4.7);
e) Anfangs- und/oder Langzeit-Grenzverformungen (siehe 5.1.1 und 5.1.2);
f) Informationen über Rohrziehen und Rohrvortrieb (siehe 5.2), falls zutreffend;
g) Längszug-Elastizitätsmodul und -Festigkeit (siehe 5.3.1.2);
h) linearer Temperaturausdehnungskoeffizient (siehe 5.3.2.2 und Anhang B);
i) Tauglichkeit für den Einsatz in Bereichen mit freier Sonneneinstrahlung (siehe 5.3.3);
j) Auswahl von geeigneten Verbindungssystemen (siehe Abschnitt 6);
k) empfohlene Krümmungsradien für die Kaltverformung (siehe 7.1);
l) zulässige Verlustraten für Wasser während der Prüfung (siehe 8.2.1);
m) falls zutreffend der Zusammenhang zwischen SDR und Steifigkeit.
...

Systemes de canalisations et de gaines en plastique - Systeme d'adduction d'eau ou d'assainissement a l'extérieur de la structure des bâtiments - Pratiques pour la pose en aérien et en enterré

La présente prénorme européenne s'applique à la pose de systèmes de canalisations et de gaines en matières plastiques destinés à être utilisés pour l'adduction d'eau ou l'assainissement, gravitaire ou avec pression, en enterré et en aérien. Elle est destinée à être utilisée pour des tubes de dimension nominale allant jusqu'à DN 3000 inclus.
Lorsque le terme "tube" est utilisé dans la présente prénorme européenne, elle couvre également les "raccords", les produits "auxiliaires" et les "composants".
NOTE 1    Il est entendu que des recommandations et/ou des exigences supplémentaires sont détaillées dans les normes de systèmes individuelles concernant chaque matériau. Ceci peut s'appliquer aux cas suivants traités dans la présente prénorme européenne:
a)  les exigences particulières relatives au transport (voir 4.2.6);
b)  la hauteur maximale de stockage (voir 4.4.3 et 4.4.4);
c)  la durée maximale de stockage en plein soleil (voir 4.4.6);
d)  les conditions climatiques exigeant un stockage particulier (voir 4.4.7);
e)  la déformation limite initiale et/ou à long terme (voir 5.1.1 et 5.1.2);
f)  les informations concernant l'emploi de charrue-taupe et le forage (voir 5.2), le cas échéant;
g)  le module et la résistance en traction longitudinale (voir 5.3.1.2);
h)  le coefficient de dilatation thermique linéaire (voir 5.3.2.2 et annexe B);
i)  l'aptitude à l'emploi dans des zones exposées au soleil (voir 5.3.3);
j)  le choix du système d'assemblage approprié (voir l'article 6);
k)  les rayons de flexion recommandés pour le cintrage à froid (voir 7.1);
l)  les taux admis de perte d'eau (ou de perte de pression) au cours de l'essai (voir 8.2.1);
m)  le cas échéant, la relation entre SDR et rigidité.
...

Cevni sistemi iz polimernih materialov - Sistemi zunaj stavb za transport vode ali kanalizacije - Postopki za vgradnjo nad zemljo in pod njo

General Information

• Status: Withdrawn
• Publication Date: 31-May-2002
• Withdrawal Date: 08-Jan-2014
• ICS: 23.040.03 - Pipeline and its parts for external water conveyance systems
• ICS: 93.025 - External water conveyance systems
• ICS: 93.030 - External sewage systems
• Technical Committee: PCV - Plastic pipes, fittings and valves
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 08-Jan-2014
• Due Date: 31-Jan-2014
• Completion Date: 09-Jan-2014
• Directive: 305/2011 - Regulation (eu) No 305/2011 of the European Parliament and of the Council of 9 march 2011 laying down harmonised conditions for the marketing of construction products and repealing council directive 89/106/eec
• Directive: 89/106/EEC - Construction products
• Ref Project: ENV 1046:2001 - Plastics piping and ducting systems - Systems outside building structures for the conveyance of water or sewage - Practices for installation above and below ground

Relations

• Replaced By: SIST-TP CEN/TR 1046:2014 - Thermoplastics piping and ducting systems - Systems outside building structures for the conveyance of water or sewage - Practices for underground installation
• Effective Date: 01-Feb-2014

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2002
Cevni sistemi iz polimernih materialov - Sistemi zunaj stavb za transport vode ali
kanalizacije - Postopki za vgradnjo nad zemljo in pod njo
Plastics piping and ducting systems - Systems outside building structures for the
conveyance of water or sewage - Practices for installation above and below ground
Kunststoff-Rohrleitungs- und Schutzrohr-Systeme - Systeme außerhalb der
Gebäudestruktur zum Transport von Wasser oder Abwasser - Verfahren zur ober- und
unterirdischen Verlegung
Systemes de canalisations et de gaines en plastique - Systeme d'adduction d'eau ou
d'assainissement a l'extérieur de la structure des bâtiments - Pratiques pour la pose en
aérien et en enterré
Ta slovenski standard je istoveten z: ENV 1046:2001
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
93.025 Zunanji sistemi za prevajanje External water conveyance
vode systems
93.030 Zunanji sistemi za odpadno External sewage systems
vodo
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN PRESTANDARD
ENV 1046
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
July 2001
ICS 23.040.01
English version
Plastics piping and ducting systems - Systems outside building
structures for the conveyance of water or sewage - Practices for
installation above and below ground
Systèmes de canalisations et de gaines en plastique - Kunststoff-Rohrleitungs- und Schutzrohr-Systeme -
Système d'adduction d'eau ou d'assainissement à Systeme außerhalb der Gebäudestruktur zum Transport
l'extérieur de la structure des bâtiments - Pratiques pour la von Wasser oder Abwasser - Verfahren zur ober- und
pose en aérien et en enterré unterirdischen Verlegung
This European Prestandard (ENV) was approved by CEN on 5 July 2001 as a prospective standard for provisional application.
The period of validity of this ENV 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 ENV can be converted into a European Standard.
CEN members are required to announce the existence of this ENV in the same way as for an EN and to make the ENV available promptly
at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final
decision about the possible conversion of the ENV into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2001 CEN All rights of exploitation in any form and by any means reserved Ref. No. ENV 1046:2001 E
worldwide for CEN national Members.

Contents
Page
Foreword .3
Introduction .4
1 Scope.5
2 Normative references.5
3 Terms and definitions .5
3.1 Terminology.5
3.2 Symbols.6
4 Transport, handling and storage at depots and sites.9
4.1 General.9
4.2 Transport .9
4.3 Handling.9
4.4 Storage .9
5 Installation.10
5.1 Pipes in trenches .10
5.2 Special installation techniques.26
5.3 Laying of pipes above ground.26
6 Methods of assembly (jointing).30
6.1 General.30
6.2 Joints using an elastomeric seal.30
6.3 Mechanical compression joints .31
6.4 Other joints and jointing methods.32
7 Bends.33
7.1 Cold bending.33
7.2 Hot bending .33
8 Inspection and testing .33
8.1 Inspection .33
8.2 Testing.33
Annex A (normative) Classification of soils.34
Annex B (normative) Thermal considerations on laying of pipes above ground .36
B.1 General.36
B.2 L-shaped expansion joint.38
B.3 Z-shaped expansion joint .40
B.4 U-shaped expansion joints .42
Annex C Behaviour of buried flexible pipes.44
(informative)
Annex D (normative) Joint and jointing examples .46
D.1 Joints capable of resisting end thrust .46
D.2 Mechanical threaded joints.52
Annex E (normative) Beam-column theory.53
E.1 Scope of the design procedure.53
E.2 Loads.54
E.3 Water column compression.57
E.4 Deflection.57
E.5 Stresses.58
E.6 Buckling .60
Bibliography.64
Foreword
This European Prestandard has been prepared by Technical Committee CEN/TC 155 "Plastics piping
systems and ducting systems ", the secretariat of which is held by NEN.
This prestandard is based on the results of the work being undertaken in ISO/TC 138 "Plastics pipes,
fittings and valves for the transport of fluids", which is a Technical Committee of the International
Organization for Standardization (ISO) (see bibliography), modified as necessary to be applicable to
piping systems of any plastics materials and any relevant application.
This prestandard is a guidance document only. It provides a set of guidelines which gives correct
practices for installation of plastics piping and ducting systems outside building structures above and
below ground.
It relates to standards on general functional requirements and codes of practice.
CEN/TC 164 and CEN/TC 165 are preparing standards covering pipe laying and pipe design. When
these standards are published this prestandard will be revised to take account of those standards.
It includes the following:
Annex A, which is normative, gives criteria for classification of soils;
Annex B, which is normative, details calculation procedures for assessing thermal effects on
piping designs and/or layouts above ground;
Annex C, which is informative, describes the behaviour of buried flexible pipes;
Annex D, which is normative, describes joints and examples thereof;
Annex E, which is normative, details calculation procedures for assessing the need to apply the
beam-column theory and determining the maximum deflection of above ground pipes;
Bibliography.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this European Prestandard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

Introduction
This prestandard contains guidance for installation procedures for plastics piping systems and their
components intended to be used above or below ground for pressure and non-pressure applications
outside building structures. It 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".
This prestandard 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 installation.
This prestandard does not cover matters relating to renovation of existing pipeline systems using lining
techniques, or replacement of existing pipeline systems using trenchless techniques.
This prestandard is intended to be used by authorities, design engineers, installation contractors and
manufacturers.
In this prestandard, 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".
1 Scope
This prestandard is applicable to the installation of plastics piping systems to be used for the
conveyance of water or sewage under gravity and pressure conditions above and below ground. It is
intended to be used for pipes of nominal size up to and including DN 3000.
Where in this prestandard the term "pipe" is used then it serves also to cover any "fittings", "ancillary"
products and "components".
NOTE 1 It is assumed that additional recommendations and/or requirements are detailed in the individual materials
System Standards. Instances where this is expected to apply include those indicated in this prestandard as follows:
a) any special transportation requirements (see 4.2.6);
b) maximum storage height (see 4.4.3 and 4.4.4);
c) maximum storage period in direct sunlight (see 4.4.6);
d) any climatic conditions requiring special storage (see 4.4.7);
e) limiting initial and/or long-term deflections (see 5.1.1 and 5.1.2);
f) information on mole ploughing and boring (see and 5.2), if applicable;
g) longitudinal tensile modulus and strength (see 5.3.1.2);
h) coefficient of thermal linear expansion (see 5.3.2.2 and Annex B);
i) suitability for use in areas exposed to sunlight (see 5.3.3);
j) selection of appropriate jointing system (see clause 6);
k) recommended radii of curvature for cold bending (see 7.1);
l) permitted rates of loss of water under test (see 8.2.1);
m) if applicable the relationship between SDR and stiffness.
NOTE 2 Guidance and instructions concerning commissioning of systems can be found in the standards prepared by
CEN/TC 164 and by CEN/TC 165 and the relevant national and/or local regulations.
NOTE 3 Concerning the character of this document see Foreword and Introduction.
2  Normative references
This prestandard incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and the publications are
listed hereafter. For dated references, subsequent amendments to, or revisions of, any of these
publications apply to this prestandard only when incorporated in it by amendment or revision. For
undated references the latest edition of the publication referred to applies (including amendments).
EN 1295-1:1997, Structural design of buried pipelines under various conditions of loading Part 1:
General requirements
3  Terms and definitions
3.1  Terminology
See Figure 1 for an illustration of the meaning and limits of the terms used in this prestandard.
key
1 Trench width, b
2 Depth of cover
3 100 mm to 300 mm
4 Ground surface
5 Native soil
6 Embedment
7 Main backfill
8 Pipe zone
9 Haunch zone
10 Trench grade
11 Trench bottom
12 Foundation, if required
13 Bedding, if required
Figure 1 — Trench cross-section showing terminology
3.2  Symbols
For the purposes of this prestandard, the following symbols apply:
A
a specific type of U-shaped expansion joint (see Figure B.6);
a
clearance between a pipe joint and an adjacent support (see Figure B.1);
A d e e
area of a pipe cross-section,  ( – )  (see Annex E);
p e
B
a specific type of U-shaped expansion joint (see Figure B.7);
b
width of a trench cross-section (see Figure 1);
b
bearing width of a cradle support (see Figure 17);
c
b
horizontal clearance between the pipe or fitting and the trench sidewall or an adjacent pipe or
S
fitting (see Figure 1);
c
a factor for thermal expansion in relationships between fixed anchorages and compensation
section pipe lengths (see Annex B);
d
(mean) external diameter of a pipe (see Figure 1);
e
d (mean) internal diameter of a pipe [see equation (E.5)];
i
DN nominal size of a pipe and associated fittings;
e pipe wall thickness;
E hoop tensile modulus of elasticity (see Annex E);
H
E elasticity modulus of the pipe material in the longitudinal direction (see Annex B and Annex E);
x
F net sum of axial loads (see Annex E);
f deflection multiplication factor (deflection) (see Annex E);
f deflection multiplication factor (end rotation) (see Annex E);
f deflection multiplication factor (moment) (see Annex E);
F horizontal reaction force on a pipework anchorage or sleeve (see Figure B.4);
H
F thermal load (see Annex E);
F Poisson load (see Annex E);
F load due to pressure (see Annex E);
p
F factor of safety [see equation (5)];
S
F reaction force on a fixed anchorage by thermal expansion or contraction of a pipe [see
T
equation (B.2)];
F vertical reaction force on a pipework anchorage or sleeve (see Figure B.4);
V
h depth of snow (see Annex E);
s
second axial moment of area (for a pipe) (see Annex B and Annex E);
L first pipe length along the span (L ) of an expansion joint from a fixed point to the offset leg
1 a
(see figures B.4, B.5 and B.6);
L the compensation portion of the first pipe length along the span of an expansion joint, i.e. from
1C
the offset pipe leg to the nearest preceding guide or anchorage (see figures B.4 to B.7);
L second pipe length along the span (L ) of an expansion joint from the first offset leg to the next
2 a
offset leg or fixed point (see figures B.5 and B.6);
L the compensation portion of the second pipe length along the span of an expansion joint, i.e.
2C
from the offset pipe leg to the next guide or anchorage (see Figure B.5);
L third pipe length along the span (L ) of an expansion joint from the second offset leg to the
3 a
next fixed point;
L the compensation portion of the third pipe length along the span of an expansion joint, i.e.
3C
from a second offset pipe leg to the next guide or anchorage (see Figure B.6);
L span of supported pipework between fixed anchorages;
a
l buckling length (see Annex E);
b
L the compensation portion of a branch pipe, i.e. from the branch junction to the first guide or
BC
anchorage along the branch (see Figure B.2);
l length of the pipe influencing the deflection (see Annex E);
d
L free length of a straight pipe (see Figure B.1);
f
L free length from a fixed point of the second leg of an L-shaped expansion joint (see
L
Figure B.4);
L the compensation portion of the second leg of an L-shaped expansion joint, i.e. from the elbow
LC
to the next guide or anchorage (see Figure B.4);
L offset length of an expansion joint (see figures B.5 and B.6);
O
L the compensation portion of the offset length of an expansion joint, i.e. from the first elbow to
OC
the next guide, anchorage or elbow (see Figure B.3);
L length of pipe span between support centres (see Annex B and Annex E);
S
L maximum span width for pipe support (see Annex B);
S,max
M compaction classification: Moderate (see Table 5);
M bending moment (see Annex E);
b
N compaction classification: Not (see Table 5);
p internal pressure (see Annex E);
P , P fixed points associated with expansion joints in a piping system (see figures B.3 to B.6);
1 2
p critical negative pressure creating global buckling (see Annex E);
crit
Q net sum of all axial loads acting on the pipe and in the liquid column (see Annex E);
q sum of laterally distributed loads (see Annex E);
q linear load arising from the mass of the pipework itself (see Annex E);
Q critical buckling load for the pipe as a column (see Annex E);
crit
q linear load arising from the mass of liquid in a full pipe [see equation (E.8)];
l
q linear load arising from snow supported by the pipe [see equation (E.9)];
s
R ratio of offset to linear compensation piping lengths [see equation (B.9)];
R ratio of linear to offset compensation piping lengths [see equation (B.10)];
S initial specific stiffness (see Tables 1 and 2);
SN stiffness number or classification (see Tables 1 and 2);
W compaction classification: Well (see Table 5);
linear coefficient of thermal expansion;
L
deflection of pipe at midspan between supports;
+l thermal expansion;
l thermal contraction;
l variation in length;
L thermal expansion of a pipe in horizontal direction [see equation (B.5a)];
1,h
L thermal expansion of a pipe in vertical direction [see equation (B.5b)];
L,v
T temperature difference creating load;
correction factor (see Table E.5);
apparent specific weight of pipe wall material [see equation (E.7)];
specific weight of liquid contained in pipe in service [see equation (E.8)];
l
specific weight of snow (see Table E.5);
s
Poisson ratio (see Table E.5);
axial bending stress (see Annex E);
b
axial compressive bending stress (see Annex E);
c,b
critical axial compressive stress (see Annex E);
c,crit
maximum axial compressive stress (see Annex E);
c,max
axial compressive normal stress (see Annex E);
c,n
axial normal stress (see Annex E);
n
allowable longitudinal stress in the pipe wall;
x,d
longitudinal stress in the pipe wall induced by internal pressure;
x,p
longitudinal stress in the pipe wall induced by distributed loads;
x,q
remaining longitudinal design stress capability in the pipe wall [see equation (B.3)];
x,r
longitudinal stress limit for long-term failure strength.
x,u,L
4  Transport, handling and storage at depots and sites
4.1  General
Plastics pipes may be supplied in straight lengths or coiled forms (either free standing or on drums).
NOTE Attention is drawn to the need for consideration of personnel safety during the transport, handling and storage,
especially in wet and cold weather conditions. Particular care should be exercised when decoiling coiled pipes as considerable
forces can be released.
Additional information should be given in the System Standards, if applicable.
4.2  Transport
NOTE Attention is drawn to the need to conform to national and/or local transport regulations.
4.2.1  When transporting pipes, use either flat-bed or purpose made vehicles. The bed shall be free
from nails and other protuberances.
4.2.2  Secure the pipes effectively before transporting them. Any side support post shall be flat and
free from sharp edges.
4.2.3  When loading socket-ended pipes, stack the pipes so that the sockets are not in contact with
adjacent pipes.
4.2.4  The largest diameter pipes should be placed on the bed of the vehicle.
4.2.5  Pipes should not be allowed to overhang the vehicle by more than five times the nominal size,
DN, expressed in metres or 2 m, whichever is the smaller. These recommendations may not apply
when rigid bundles of pipes are being transported.
4.2.6  When pipes and/or fittings require special transportation practices the manufacturer shall notify
the customer of the procedures to be used.
4.3  Handling
4.3.1  When handling the pipes, take care to prevent damage.
4.3.2  Plastics pipes can be damaged when in contact with sharp objects or if dropped, thrown or
dragged along the ground.
4.3.3  It is preferable to use fabric slings or rope to lift the pipe. Metal bars, slings, hooks or chains will
damage the pipe if they are used incorrectly. When loading or unloading pipes with fork lift equipment,
then only fork lift trucks with smooth forks should be used. Care should be taken to ensure that forks
do not strike the pipe when lifting.
4.3.4  The impact resistance of plastics pipes is reduced at very low temperatures and under these
conditions, take more care during handling.
4.4  Storage
4.4.1  Although plastics pipes are light, durable and resilient, take reasonable precautions during
storage.
4.4.2  Stack the pipes or coils on surfaces free from sharp objects, stones or projections. For the
maximum stacking height, see the referring standard.
When storing pipes in racks, ensure that any sockets lie alternately within the pile and project
sufficiently for the pipes to be correctly supported.
4.4.3  Where the pipes are supplied in coils, store them either vertically or stacked flat one on top of
the other, taking care to protect the pipes from extremes of temperature. For further information, see
the referring standard.
Each coil of pipe of nominal size greater than DN 90 should be stored vertically in purpose-built racks
or cradles. For further information, see the referring standard.
4.4.4  When straight pipes are stored on racks, these shall provide sufficient support to prevent
permanent deformation.
4.4.5  Do not place pipes or rubber seals in close proximity to fuels, solvents, oils, greases, paints or
heat sources.
4.4.6  For the recommended maximum storage period for pipes in direct sunlight, see the referring
standard.
4.4.7  In extreme climatic conditions special storage requirements may be necessary. Follow the
advice given in the manufacturer's technical data accordingly.
4.4.8  If pipes are supplied in a bundle or other packaging, the restraints and/or packaging should be
removed as late as possible prior to installation.
5  Installation
5.1  Pipes in trenches
5.1.1  Behaviour of flexible pipes under load
The behaviour of a pipe when subject to a load depends upon whether it is flexible or rigid. Plastics
pipes are flexible. When loaded a flexible pipe deflects and presses into the surrounding material. This
generates a reaction in the surrounding material which controls deflection of the pipe. The amount of
deflection which occurs is limited by the care exercised in the selection and laying of the bedding and
sidefill materials. Hence flexible pipes rely for their load-bearing properties on the bedding and sidefill
materials.
In the case of rigid pipes, the load on a pipe is borne primarily by the inherent strength of the pipe
material and when this load exceeds a limiting value the pipe breaks. Standards for rigid pipes,
therefore, usually include ultimate crushing strength tests to determine this limiting value and thus
assess the loadings which may be allowed above the installed pipe.
Flexible pipes on the other hand deflect under load and can be deflected to a high degree without
fracture. The level of deflection reached by a buried pipe depends on the properties of the surrounding
material and to a much less extent on the stiffness of the pipe but not on its strength properties. Hence
for flexible pipes the crushing strength test and design procedures applied to rigid pipes are not
appropriate.
When a flexible pipe is installed and backfilled it will be deflected. This is called the initial deflection.
The pipe continues slowly to have an increase in deflection but reaches a limiting value within a
reasonable period of time. The use of the installation procedures detailed in this prestandard will
minimize the levels of both the initial and final deflections. If the pipeline is pressurized then a
reduction in the amount of deflection will occur. A more detailed description of this behaviour is given
in Annex C.
5.1.2  Limiting deflection
There are several methods of structural design (see EN 1295-1:1997) that are used to estimate the
deflection of a pipe under load but, though they are capable of being in reasonable agreement, they do
not give exactly the same answers for a given condition. The values calculated are usually the
expected average deflections.
Pipes made from different materials have different limiting deflection levels. For the applicable
maximum permissible initial and, if appropriate, long-term deflection see the relevant System
Standard. If this installation prestandard is followed it is expected that the deflections will be less than
the limiting values given in the relevant System Standards.
Where it can be expected that a product covered by the System Standard may be delivered with some
distortion, e.g. pipes delivered in coils, then this should be stated. The average deflection is to be
assumed to be in addition to this distortion.
5.1.3  Design considerations
5.1.3.1  General
If it is essential to determine the soil conditions that relate to trench construction and pipe installation
prior to construction, the native soil and the backfill material shall be classified in accordance with
Annex A. The classification shall be used to choose a suitable pipe stiffness in accordance
with 5.1.3.2.
NOTE The classification will also indicate the areas of suitable materials for pipe zone backfill, so that importation of
material may be minimized. Native materials conforming to 5.1.6.3 and group 1, 2, 3 and 4 are all suitable as backfill in the
pipe zone. If backfill materials have to be imported it is suggested that group 1 or 2 materials are used.
5.1.3.2  Choice of pipe stiffness
The choice of pipe stiffness shall be made either using the tables in this prestandard or on the basis of
calculations in accordance with EN 1295-1:1997 or on the basis of previous experience.
Where calculations show that a pipe stiffness lower than that given in Table 1 or Table 2 is
appropriate, then pipes with this lower stiffness may be used. Where pipes are intended to be used in
conditions where they have by previous experience proved to be satisfactory it is not necessary to
verify this by detailed calculation even though their stiffness may be lower than the appropriate value
given in Table 1 or Table 2.
If such experience is not available then the minimum stiffness required shall be selected from Table 1
or Table 2. These tables have been prepared to cover the following conditions:
a) non-trafficked areas with depths of cover between 1 m and 3 m and between 3 m and 6 m see
Table 1);
b) trafficked areas with depths of cover between 1 m and 3 m and between 3 m and 6 m (see
Table 2).
In the absence of prior satisfactory experience, where pipes have a depth of cover less than 1 m or
more than 6 m the pipe stiffness and the installation shall be designed by calculation.
Where a System Standard uses SDR for classification purposes instead of stiffness it shall also give
the equivalent stiffness values in its relevant part.
Generally the choice of pipe stiffness depends upon the native soil, the pipe zone backfill material and
its compaction, the depth of cover, the loading conditions and the limiting properties of the pipes.
In order to make a choice of pipe stiffness possible, the native soil and backfill materials have been
classified into six main groups as described in Annex A.
Based on the native soil, backfill details and depth of cover, the minimum pipe stiffness is selected
from Tables 1 or 2. Using a pipe of this stiffness installed in an embedment formed from the
appropriate backfill material compacted to the specified degree of compaction should result in
deflections of not more than the limiting values given in the relevant System Standard.
NOTE Whenever a common structural design method for buried pipelines (at least one for plastics materials) becomes
available, Tables 1 and 2 will be reviewed.
Table 1 — Recommended minimum stiffness for non-trafficked areas
Values in newtons per square metres
1)
Pipe stiffness
Backfill Compaction-
2)
Material class For depth of cover 1 m and 3 m
3)
group 3)
Undisturbed native soil group
1 234 5 6
W 1250 1250 2000 2000 4000 5000
1 M 1250 2000 2000 4000 5000 6300
N 2000 2000 2000 4000 8000 10000
W 2000 2000 4000 5000 5000
2 M 2000 4000 5000 6300 6300
N 4000 6300 8000 8000 **
W 4000 6300 8000 8000
3 M 6300 8000 10000 **
N ** ** ** **
W 6300 8000 8000
4 M ** ** **
N ** ** **
For depth of cover > 3 m and 6 m
W 2000 2000 2500 4000 5000 6300
M 2000 4000 4000 5000 6300 8000
W 4000 4000 5000 8000 8000
M 5000 5000 8000 10000 **
W 6300 8000 10000 **
M ** ** ** **
W ** ** **
M ** ** **
1) Initial specific stiffness, S, determined in accordance with the relevant System Standards
2) See Table 5.
3) See Annex A.
**) Structural design is necessary to determine trench details and pipe stiffness.
NOTE 1 If a pipe of given stiffness is intended to be used under more severe loading conditions (than originally
envisaged), it may be possible to achieve this by the use of a higher class of installation. It is essential that this is verified
by structural design.
NOTE 2 Attention is drawn to the limitations that may apply due to negative pressure in service and due to mechanical
compaction requirements during installation for pipe stiffness up to and including SN 2500.
NOTE 3 In cases of combined loading conditions (such as soil load plus internal pressure) special considerations and
possibly precautions should be taken.
Table 2 — Recommended minimum stiffness for trafficked areas
Values in newtons per square metres
1)
Pipe stiffness
Backfill Compaction
2)
Material class For depth of cover 1 m and 3 m
3)
group 3)
Undisturbed native soil group
12 34 5 6
1 W 4000 4000 6300 8000 10000 **
2 W 6300 8000 10000 ** **
3 W 10000 ** ** **
4 W ** ** **
For depth of cover > 3 m and 6 m
1 W 2000 2000 2500 4000 5000 6300
2 W 4000 4000 5000 8000 8000
3 W 6300 8000 10000 **
4 W ** ** **
1) Initial specific stiffness, S, determined in accordance with the relevant System Standards
2) See Table 5.
3) See Annex A.
**) Structural design is necessary to determine trench details and pipe stiffness.
NOTE 1 If a pipe of given stiffness is intended to be used under more severe loading conditions (than originally envisaged),
it may be possible to achieve this by the use of a higher class of installation. It is essential that this is verified by structural
design.
NOTE 2 Attention is drawn to the limitations that may apply due to negative pressure in service and due to mechanical
compaction requirements during installation for pipe stiffness up to and including SN 2500.
NOTE 3 In cases of combined loading conditions (such as soil load plus internal pressure) special considerations and
possibly precautions should be taken.
5.1.3.3  Types of installation
The two most commonly used practices for the installation of plastics pipes are either to surround the
pipe with the same material (see Figure 2) or splitting the surround into two materials or degrees of
consolidation (see Figure 3). The use of such a split embedment is normally only found to be practical
with pipes of nominal sizes greater than DN 600.
Key
1 Pipe zone
2 Bedding
Figure 2 — Trench with full surround pipe zone
Key
1 Split level
2 Secondary pipe zone backfill
3 Primary pipe zone backfill:
0,5d height 0,7d
e e
4 Bedding
5 Invert
Figure 3 — Trench with split surround pipe zone
If a split embedment is used it is important that the split level between the lower and upper material
should occur at between 50 % and 70 % of the pipe diameter above the bedding (see Figure 3). This
is to prevent the possibility of generating high stresses/strains at the split level when the pipe deflects.
To ensure that the split surround provides the same degree of support to the pipe as the full surround
the following rules shall be applied:
a) the material in the primary pipe zone (see Figure 3) of a split surround should be at least one
grade stiffer than that required in the pipe zone of a full surround, where a grade is a particular
combination of material group and a compaction class, a change by one step in either of which
comprises a one-step-change of grade. Thus the one grade change may be achieved by either
increasing the compaction class or using a higher group of material (see Table 5). For instance, if
an application using a full surround requires backfill material group 2 moderately compacted, then
a split surround would require either a well compacted group 2 material or a group 1 material with
moderate compaction;
b) the material in the secondary pipe zone (see Figure 3) of a split surround may be up to two
grades less stiff than that in the pipe zone of a full surround. But care shall be taken that the
maximum total difference between primary and secondary pipe zone is not more than two grades.
This also may be achieved by changing either the material group and/or the compaction class. In
any case the lowest soil stiffness which is allowed is achieved using an uncompacted material of
group 4. For instance, for the case described in item a) the requirements would be fulfilled in the
secondary pipe zone by using uncompacted group 2 (one grade lower) or moderately compacted
group 3 (also one grade lower) or uncompacted group 3 (three grades lower) material. The last
option is not allowed because in this case the maximum two grades difference would be
exceeded.
5.1.3.4  Parallel piping systems
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.
The pipe zone backfill material between the pipes shall be compacted to the same compaction class
as the material between the pipe and the trench wall.
In cases of parallel piping systems laid within a stepped trench (see Figure 4) the pipe zone backfill
material shall be granular and shall be compacted to compaction class W.
Key
1 Well compacted (class W)
Figure 4 — Parallel pipes in a stepped trench
5.1.4  Trench construction
5.1.4.1  Safety
Operations in trenches are carried out in potentially hazardous conditions.
Where appropriate shore, sheet, brace, slope or otherwise support the trench walls to protect any
person in the trench. Take precautions to prevent objects falling into the trench, or its collapse caused
by the position or movements of adjacent machinery or equipment, whilst the trench is occupied.
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 spoil bank should not be allowed to endanger the stability of
the excavation.
NOTE Attention is drawn to any local and/or national safety regulations.
5.1.4.2  Trench width
The width of the trench at the springline of the pipe need 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. Typical values for b (see figures 1 and 2) are given in Table 3.
S
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.
Table 3 — Typical values for b
S
Nominal size b
S
DN mm
DN 300 200
300 < DN 900 300
900 < DN 1600 400
1600 < DN 2400 600
2400 < DN 3000 900
5.1.4.3  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 should be provided to prevent accidental pipe flotation in potentially high ground water
areas. Generally it is 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.
5.1.4.4  Trench bottom
5.1.4.4.1  Trench grade
The surface at the trench grade (see Figure 1) shall be continuous, uniform and free of particles
greater than those specified in Table 4 for the applicable pipe size.
5.1.4.4.2  Over-excavation
Where rock, cobbles or hardpan are encountered, over-excavate the trench bottom.
Quicksands or similar soils, organic soils or soils that exhibit a volume change with a change in
moisture content may be encountered in the bottom of the trench. In such cases the engineer may
specify that further excavation be carried out and a foundation zone be provided. 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 primary pipe zone
and shall be compacted to class W (see 5.1.6.3).
Compact the foundation material uniformly in accordance with 5.1.6.2 and 5.1.6.3.
5.1.4.4.3  Special conditions
When settlement of the soil can be expected, such as when a pipe passes through a soil transition,
then the use of geotextiles as shown in Figure 7 can provide a solution. However, where large-scale
soil movements are anticipated then this solution may not be effective. In such cases it is
recommended that expert advice is sought.
Among special conditions which may be encountered during laying, is running or standing water
occurring in the bottom of the trench, or the bottom of the trench exhibits a quick tendency. In these
cases remove the water by means such as well points or underdrains until the pipe has been installed
and the trench backfilled to a height sufficient to prevent flotation of the pipeline or collapse of the
trench. The gradation of the pipe zone backfill, bedding and foundation material shall be such that,
under saturated conditions, fines from these areas will not migrate into the adjacent soil of the trench
bottom or walls, and material from the trench bottom or walls will not migrate into those areas. Any
migration or movement of soil particles from one area to another can result in the loss of the
necessary foundation or side support for the pipe, or both. The migration of fine materials can be
prevented by use of a suitable filter fabric, as shown in Figure 5.
Key
1  Pipe zone
2 Bedding
3 Filter fabric
Figure 5 — Protection against material migration
If filter fabrics are welded together, the fabrics shall be laid with at least 0,3 m overlapping. Unwelded
fabrics shall be laid with an overlap of at least 0,5 m.
When the soil is weak or soft such that it is not possible for persons to work safely in the trench then
reinforcement of the trench may be necessary before laying the bedding. Reinforcement of the trench
bottom can be made using a wooden mattress (see Figure 6), reinforced concrete or geotextiles. If the
ground water table could be adjacent to the mattress, boards impregnated with appropriate
preservatives are recommended (see the referring standard).
Key
1 Bedding
2 Wooden boards
3 Connecting boards
4 Minimum width
Figure 6 — Trench bottom reinforced by a wooden mattress
Typical us
...