SIST-TS CEN/TS 15223:2018

SLOVENSKI STANDARD
kSIST-TS FprCEN/TS 15223:2015
01-julij-2015
&HYQLVLVWHPLL]SROLPHUQLKPDWHULDORY9HOMDYQLSDUDPHWUL]DQDþUWRYDQMH
SODVWRPHUQLKFHYQLKVLVWHPRYSRORåHQLKY]HPOMR
Plastics piping systems - Validated design parameters of buried thermoplastics piping
systems
Kunststoff-Rohrleitungssysteme - Gültige Berechnungsparameter von erdverlegten
thermoplastischen Rohrleitungssystemen
Systèmes de canalisations en matières plastiques - Paramètres de calcul validés pour
les systèmes enterrés de canalisations en matières thermoplastiques
Ta slovenski standard je istoveten z: FprCEN/TS 15223
ICS:
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
kSIST-TS FprCEN/TS 15223:2015 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 15223:2015

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kSIST-TS FprCEN/TS 15223:2015

TECHNICAL SPECIFICATION
FINAL DRAFT
FprCEN/TS 15223
SPÉCIFICATION TECHNIQUE

TECHNISCHE SPEZIFIKATION

May 2015
ICS 23.040.01 Will supersede CEN/TS 15223:2008
English Version
Plastics piping systems - Validated design parameters of buried
thermoplastics piping systems
Systèmes de canalisations en matières plastiques - Kunststoff-Rohrleitungssysteme - Gültige
Paramètres de calcul validés pour les systèmes enterrés de Berechnungsparameter von erdverlegten thermoplastischen
canalisations en matières thermoplastiques Rohrleitungssystemen


This draft Technical Specification is submitted to CEN members for formal 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TS 15223:2015 E
worldwide for CEN national Members.

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Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms, definitions, symbols and abbreviations .6
3.1 Terms and definitions .6
3.2 Symbols .8
3.3 Abbreviations .9
4 Route for structural design .9
4.1 General .9
4.2 Structural design based on practical experience . 11
4.3 Structural design based on design calculations . 12
5 Functional design non-pressure . 12
5.1 General . 12
5.2 Material . 12
5.3 Strain . 12
5.4 Flow capacity . 13
5.5 Temperature . 14
5.6 Ring buckling . 14
5.7 Longitudinal effects . 16
5.7.1 General . 16
5.7.2 Axial bending . 16
5.7.3 Allowable cold bending . 16
6 Functional design pressure . 17
6.1 General . 17
6.2 Material . 17
6.3 Design coefficient and design stress . 17
6.4 Pressure rating PN. 18
6.5 Flow capacity . 18
6.6 Temperature . 18
6.6.1 Temperature dependance of the nominal working pressure of PE piping systems . 18
6.6.2 Temperature dependance of the nominal working pressure of PVC piping systems . 18
6.7 Working pressure . 19
6.7.1 Buckling reistance Negative pressure applications . 19
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6.7.2 PFA, PMA and PEA . 19
6.8 Water hammer . 20
6.9 Ring buckling . 21
6.10 Longitudinal effects . 22
6.10.1 Axial bending . 22
6.10.2 Cold bending limits . 23
6.11 Joints . 23
7 Structural design . 24
7.1 General . 24
7.2 Behavior of installed plastic pipes in soil . 24
7.3 structural design based on practical experience . 26
7.3.1 General . 26
7.3.2 Values for installation phase . 26
7.3.3 Values Final deflection . 27
7.4 Structural design based on a design calculations . 28
8 Guidance for verification of installation . 29
9 Commissioning . 29
9.1 General For inspection and testing during and after installation CEN/TR 1046 can be used.

The focus during commissioning should be on leaktightness and permissabe deflection. . 29
9.2 Non pressure pipe . 29
9.3 Pressure pipe . 29
Annex A (informative) Time dependency of stress and strain in buried flexible piping systems . 30
Annex B (informative) Soil / pipe behaviour . 31
Annex C (informative) Verification against limit states for non-pressure pipes . 33
Annex D (informative) Flow capacity charts (non-pressure) . 34
Annex E (informative) Flow capacity charts (pressure) . 35
Bibliography . 36

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Foreword
This document (FprCEN/TS 15223:2015) 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 Formal Vote.
This document will supersede CEN/TS 15223:2008.
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Introduction
In Europe, several design methods exist and some are still under development. The plastics pipes industry
has carried out a lot of research with full-scale trials. From these researches, graphs have been made that
show the deflection in the pipes immediately after installation. In addition, the so-called settlement period is
measured. This settlement will always take place. In case that heavy traffic is present, the final deflection will
be reached faster.
It is strongly advised to check any calculated deflection with the values in the three design graphs.
The information compiled is meant to be used by designers. The values given are meant for general guidance.
For the purpose of design using simple methods, two compactible soil groups are used, granular and
cohesive.
If applicable, reference is made to EN 1295-1, EN 1610, CEN/TR 1046 and national practices.
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1 Scope
This Technical Specification covers validated design parameters of buried thermoplastics piping systems for
functional and structural design for the following applications:
– pressure (excluding piping systems for gaseous fluids and industrial applications);
– non-pressure.
The functional design is based on relevant standards and commonly used practices.
Depending on the project parameters, the route for structural design can be
– either established by long term experience (within certain limitations),
– or calculated according to CEN/TR 1295-2 [8] by using thermoplastic pipe material related properties and
design criteria.
NOTE The route is shown in the flowchart given in Figure 1 in 4.1.
Since in practice precise details of types of soil and installation conditions are not always available at the
design stage, the choice of design assumptions is left to the judgement of the designer/specifier. In this
connection, this guide can only provide general indications and advice.
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 476, General requirements for components used in drains and sewers
EN 805, Water supply - Requirements for systems and components outside buildings
EN 1295-1, Structural design of buried pipelines under various conditions of loading - Part 1: General
requirements
FprEN 1610:2015, Construction and testing of drains and sewers
CEN/TR 1046:2013, Thermoplastics piping and ducting systems - Systems outside building structures for the
conveyance of water or sewage - Practices for underground installation
EN ISO 9969, Thermoplastics pipes - Determination of ring stiffness (ISO 9969)
EN ISO 12162, Thermoplastics materials for pipes and fittings for pressure applications - Classification,
designation and design coefficient (ISO 12162)
EN ISO 13968, Plastics piping and ducting systems - Thermoplastics pipes - Determination of ring flexibility
(ISO 13968)
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3 Terms, definitions, symbols and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
constant load
load on a pipe, e.g. from internal pressure, that is not changing with time
3.1.2
deflection
deviation of the circle cross section of the pipe
Note 1 to entry: Deflection is expressed as percentage [%].
3.1.3
design stress
σ
s
allowable stress for a given application and derived from the MRS by dividing it by the design coefficient C
Note 1 to entry: Design stress is expressed in megapascals [MPa].
3.1.4
minimum required strength
MRS
value of σ , rounded down to the next smaller value of the R10 series or of the R20 series depending on
LPL
the value of σ
LPL
Note 1 to entry: R10 and R20 series are the Renard number series according to ISO 3 [1] and ISO 497 [2].
3.1.5
design coefficient
C
design coefficient with a value greater than one, which takes into consideration service conditions as well as
properties of the components of a piping system others than those represented in the lower confidence limit
3.1.6
nominal pressure
PN
numerical designation used for reference purposes related to the mechanical characteristics of the component
of a piping system and corresponding to the maximum continuous operating pressure in bars
3.1.7
pipe stiffness
S
p
theoretical pipe stiffness determined with the Young’s modulus and the Poisson's ratio
3.1.8
critical buckling pressure
q
crit
critical internal pressure causing buckling of the pipe
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3.1.9
nominal stiffness
SN
numerical designation of the ring stiffness of a pipe or fitting, which is a convenient round number indicating
the minimum required ring stiffness of the pipe or fitting
Note 1 to entry: It is designated by the letters “SN” followed by the appropriate number.
3.1.10
compaction factor
C
f
factor that gives the settlement of the surrounding soil
3.2 Symbols
For the purposes of this document, the following symbols apply.
C design coefficient
C 100 year design coefficient
100
C 50 year design coefficient
50
C deflection factor, in percent
f
d nominal outside diameter of the pipe, in millimetres
n
d mean outside diameter of the pipe, in millimetres
em
D the midwall diameter, in millimetres
m
D outside diameter of the pipe, in millimetres
u
e wall thickness of the pipe, in millimetres
E the Young’s modulus of the pipe, in megapascals
p
E tangent modulus, in kilopascals
t
f application rating factor
a
f temperature rating factor
τ
2
g gravity, in m/s
K
value of the measured molecular weight
k absolute roughness, in millimetres
2
k viscosity of water, in m /s
water
q critical buckling pressure, in kilopascals
crit
R
bending radius of the pipe, in millimetres
R maximum bending radius of the pipe, in millimetres
max
S
geometrical pipe characteristic defined as S = (d (e) / (2e)
n
2 −1
S pipe stiffness value determined by (1 − υ ) / E ⋅(d /e − 2), in [MPa ]
p p em
ß
deflection correction factor
δ deflection of the pipe, in millimetres
ε
strain
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3.3 Abbreviations
For the purposes of this document, the following abbreviations apply.
HDS hydrostatic design stress
MRS minimum required strength
PE Polyethylene
PEA allowable site test pressure
PFA allowable operating pressure
PMA allowable maximum operating pressure
PN nominal pressure
PP polypropylene
PP-MD polypropylene mineral modified
PVC-O poly(vinyl chloride) oriented unplasticized
PVC-U poly(vinyl chloride) unplasticized
SDR standard dimension ratio
4 Route for structural design
4.1 General
At the start of a project, first the parameters need to be investigated as given in Clause 5.
In general creating a validated structural design of a thermo-plastics pipeline construction by applying
analytical or numerical methods is not needed – provided the parameters of the project are within the value
range given in Table 1.
Any calculated prediction of the pipe behaviour and reality is strongly dependent on the conditions used for
the calculation being the same as used for the installation. Therefore, it is important that effort is put into
controlling the input values by extensive soil surveys and monitoring the installation. In many cases, practical
and/or reference information is available and results in a sound prediction of the pipe performance.
The flowchart in Figure 1 provides the necessary steps to establish the structural design of a pipeline.
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Figure 1 — Flowchart for structural design of a pipeline
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Table 1 — Value range for design parameters
Parameter Value (range) Remark
a
Installation depth 0,80 m to 6,0 m As defined in CEN/TR 1046
AND
≥ 3 × diameter This is following from the depth of
cover requirement
Depth of cover above the pipe / ≥ 2
diameter ratio
b
Soils Granular-cohesive
c
Installation type Well, moderate, none Combination of soil, compaction,
and degree of care
Pipe stiffness ≥ SN 2 For non-pressure pipes
2
≥ 2 kN/m For pressure pipes – required
during installation and
commissioning
Pipe types Structured wall pipes with a ring Pressure pipes are regarded as
flexibility ≥ 30 % solid wall pipes.
Solid wall pipes
Traffic load All classes Railways are excluded and should
be calculated.
Diameter For diameters ≤ DN 1100
See also applicable product
standard,
Ground water table No limitation
a
In special conditions, lower installation depths (until 0,6 m) are allowed, but only in combination with installation type
'well compaction”.
b
The soil specification can be found in CEN/TR 1046.
c
Installation type 'None' is not recommended.
If the parameters of the project are within the value range as given in Table 1, the structural design can be
based on practical experience as given in 4.2.
If the parameters of the project are outside the value range as given in Table 1, the structural design can be
calculated according to 4.3.
4.2 Structural design based on practical experience
Extensive studies performed by the Plastics Pipes industry in Europe (TEPPFA / APME study [16]) and by
verification of other studies performed in various countries have shown that flexible pipes behave differently
than rigid pipes. The current theories describing the performance of flexible pipes do not reflect the true
physics of the process of pipe deflection.
The background and the results of the TEPPFA / APME study [16] are given in Clause 7.
The most important practical output of the studies is given in the design graph in Clause 7 (Figure 7).
The performance of the flexible pipes can be found in the applicable product standards of CEN/TC 155.
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4.3 Structural design based on design calculations
Structural design calculations are required in cases where installation conditions are outside the validity of
Table 1. When installation conditions are outside the range in Table 1, EN 1295-1 provides the method that
shall be used. The calculation methods proposed in CEN/TR 1295-2 [8] require material properties that are
given in Clause 5.
5 Functional design non-pressure
5.1 General
According to EN 476, the information on following aspects, when relevant, shall be provided in product
standards.
5.2 Material
Functional design calculation may require material properties. In Table 2, typical values are given, which are
valid for pressure and non-pressure applications.
a
Table 2 —Typical material values for functional design calculations
Material Poisson's Coefficient of linear Young’s Relaxation Tensile
ratio expansion modulus coefficient strength
  1/ °C MPa  MPa
−5
PVC-HI 0,4 6 × 10 2 500 0,06 40
−5
PVC 250 0,4 8 × 10 3 200 0,05 50
−5
PE 40 0,45 19 × 10 300 0,07 8
−5
PE 80 0,45 19 × 10 850 0,07 19
−5
PE 100 0,45 19 × 10 1 100 0,08 21
−5 b
PP-B 0,42 12 × 10 1 250-2 500 0,07 27
−5
PP-H 0,42 12 × 10 1 250 0,07 30
−5 c c
PP-MD 0,42 12 × 10 1 600-3 600 0,07 23–32
a
If specific values are needed related to specific products, these shall be acquired from the manufacturer or specific
standards.
b
A range has been specified according to EN 1852–1 [10]
.
c
A range has been specified depending on the filling degree.
5.3 Strain
Non-pressure pipes do not require a stress analysis because of the visco-elastic behaviour and redistribution
of stresses. A study of Janson [4] shows whether thermoplastics are strain limited or not. In this study, strain
by bending as well as through-wall strains have been evaluated. It was shown that for all practical purposes
these materials are not strain limited. If one wishes to calculate the material strain value then Table 3 supplies
conservative guidance about the levels that can be accepted.
The combination of pipe construction and integrity shall be tested by means of a ring flexibility test up to 30 %
deflection as described in EN ISO 13968. Passing this test ensures stability against buckling.
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Table 3 — Strainability, ε, for non-pressure pipes (table taken from Janson [4])
Material ε
 %
PVC-U 2,5
PE 5,0
PP 5,0
5.4 Flow capacity
The flow capacity is depending of the design and influenced by the wall roughness and the pipe deformation.
For thermoplastics pipes, wear and corrosion are non-relevant phenomena and hence ageing of the pipe has
no effect on flow performance.
In Table 4 an indication is given about typically used k values.
Table 4 — Typical values of k to determine the flow capacity
Pipes for gravity sewerage k
mm
Plastic pipes without fittings (material related) 0,25
a
Plastic pipes with fitting (each 6 m to 9 m – system related) 0,4
a
System roughness to be used for capacity calculation.
In Annex D (Figure D.1), flow capacity charts are shown where different k values given in Table 4 are used.
As far as the deformation is concerned, it is a fact that the discharge capacity is decreasing with 2 % when at
the same time the pipe is deflected up to an average deflection of 10 %. Figure 2 shows the effect of
deformation on discharge capacity.

Key
A discharge capacity, in percentage
B pipe deflection, in percentage
Figure 2 — Discharge capacity as a function of average pipe deflection
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5.5 Temperature
For non-pressure drainage and sewerage, allowed operating temperatures are given in EN 476:
— diameters ≤ 200 mm: temperatures: < 45 °C;
— diameters > 200 mm: temperatures: < 35 °C.
The plastic piping systems as covered by this Technical Specification can withstand these temperatures.
If temperatures are in excess of these temperatures, extra provisions should be made during the design.
5.6 Ring buckling
The critical buckling pressure of a buried pipe can be calculated and verified against the sustained load at the
outside of the pipe. For buried pipes, sustained load is the load exerted by groundwater and part of the soil
load. The load to be taken into account is given by the relevant standards. The resistance against buckling
can be calculated for flexible pipes using the following formulae (see Alferink [9]).
Soft soils / mud: Condition [SN] > 0,0275 E
t
2
q = 24×[SN]+ E (1)
crit t
3
Other soils:
q = 5,63 E ×[SN] (2)
crit t
where
q is the critical buckling pressure, in kilopascals;
crit
[SN] is the value of the nominal ring stiffness, expressed in kilonewtons per square meter;
E is the tangent modulus, in kilopascals.
t
When a pipe is deflected, it will result in a lower buckling resistance of the pipe.
The value found shall then be corrected with β:
β = (1 (3(δ/d )) (3)
n
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Key
A reduction factor ß
deflection δ/d , in percent
B
n
Figure 3 — Reduction factor for the buckling resistance as a function of the deflection of the pipe
EXAMPLE Pipe (SN 4) buried in granular soil at 5 m depth and with 4 m groundwater. The installation has been well
done and the deflection stays below 2,2 %.
3 2
Sustained load due to groundwater; 4 m × (1 000 × 10) N/m = 40 000 N/m . The soil load is not the same as used for the
deflection calculations in most methods. If methods discriminate between the hydrostatic load component and the shear
related component, the hydrostatic component shall be taken into account.
In this example, the buckling will be checked for groundwater only.
2
q = 5,63 √ (2 800 × 4) kN/m (4)
crit
2
q = 595 kN/m
crit
In most cases, a safety factor of 2,5 is required.
5.7 Longitudinal effects
5.7.1 General
An essential part of the design of a pipeline is to evaluate the longitudinal effects, which is not covered in most
of the recognized structural design methods as listed in EN 1295-1. Therefore, guidance is given to this issue
here.
5.7.2 Axial bending
When bending a pipe in the field, caused either during installation or by the occurrence of settlement
differences along the pipeline after installation, the following phenomena shall be checked:
The strain due to bending of a straight pipe can be calculated by Formula (5):
d
n
(5)
ε= ×100
2R
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