SIST-TP ISO/TR 4191:2018

TECHNICAL ISO/TR
REPORT 4191
Second edition
2014-01-15
Plastics piping systems for water
supply — Unplasticized poly(vinyl
chloride)(PVC-U) and oriented PVC-U
(PVC-O) — Guidance for installation
Systèmes de canalisations en plastique pour l’alimentation en eau —
Polychlorure de vinyle non plastifié (PVC-U) et orienté PVC-U (PVC-O)
— Pratique recommandée pour la pose
Reference number
ISO/TR 4191:2014(E)
©
ISO 2014

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ISO/TR 4191:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

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ISO/TR 4191:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions, symbols, and abbreviations . 2
3.1 Terms and definitions . 2
3.2 Symbols . 4
3.3 Abbreviations . 4
4 Parameters influencing design . 5
4.1 Allowable operating pressure . 5
4.2 Ring stiffness of pipes . 5
5 Hydraulic properties . 7
5.1 Loss of head . 7
6 Assembly methods . 9
6.1 General . 9
6.2 Integral rubber ring joints .13
6.3 Solvent cement joints .14
6.4 Mechanical joints .15
7 Storage, handling, and transport of pipes .15
7.1 Handling.15
7.2 Transport .16
7.3 Storage .16
7.4 Cold bending on site .17
7.5 Anchoring and thrust blocks .19
8 Storage, handling, and transport of fittings, valves, and ancillaries .21
8.1 PVC-U fittings, valves, and ancillaries are light and easy to handle .21
9 Installation .22
9.1 Installation below ground .22
9.2 Pipe deflection .25
9.3 Installation above ground .27
9.4 Installation in ducts .31
10 Commissioning by site pressure testing .31
10.1 General .31
10.2 Preparation for test .31
10.3 Test pressures .35
10.4 Applying the test .35
10.5 Interpretation of results .36
11 Contaminated soil .36
12 Corrosion protection of metal parts .36
13 Pressure surge .37
14 Usage at lower temperature .37
15 Fatigue .37
16 Repairs .38
17 Pipeline detection .39
Annex A (informative) Classification of soils .40
Bibliography .44
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ISO/TR 4191:2014(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 2, Plastics pipes and fittings for water supplies.
This second edition cancels and replaces the first edition (ISO/TR 4191:1989), which has been technically
revised.
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ISO/TR 4191:2014(E)

Introduction
This Technical Report is a guidance document and gives a recommended practice for the installation
of unplasticized poly(vinyl chloride) (PVC-U) and oriented unplasticized poly(vinyl chloride) (PVC-O)
piping systems conveying water under pressure for buried and above-ground drainage and sewerage
systems.
Molecular orientation of PVC-U results in the improvement of physical and mechanical properties.
Unless specifically mentioned, the recommendations are valid for both PVC-U and PVC-O and expressed
as PVC.
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TECHNICAL REPORT ISO/TR 4191:2014(E)
Plastics piping systems for water supply — Unplasticized
poly(vinyl chloride)(PVC-U) and oriented PVC-U (PVC-O) —
Guidance for installation
1 Scope
This ISO Technical Report gives recommended practices for installation of unplasticized
poly(vinyl chloride) (PVC-U) and oriented unplasticized poly(vinyl chloride) (PVC-O) pipes, fittings,
valves, and ancillaries when used in piping systems conveying water under pressure.
The recommendations are intended to give practical guidance of design and installation of piping
systems incorporating pipes, fittings, valves, and ancillary equipment made from PVC materials and
used for the following purposes:
— water mains and services buried in ground;
— waste water under pressure;
— conveyance of water above ground for both outside and inside buildings,
for the supply of water under pressure at approximately 20 °C (cold water) intended for human
consumption and for general purposes.
This Technical report is also applicable to components for the conveyance of water up to and including
45 °C. For temperatures between 25 °C and 45 °C, Figure 1 of ISO 1452-2:2009 applies.
In addition, recommendations are given for the connection to fittings, valves, and ancillary equipment
made from materials other than PVC.
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.
ISO 3, Preferred numbers — Series of preferred numbers
ISO 161-1, Thermoplastics pipes for the conveyance of fluids — Nominal outside diameters and nominal
pressures — Part 1: Metric series
ISO 1452-1:2009, Plastics piping systems for water supply and for buried and above-ground drainage and
sewerage under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 1: General
ISO 1452-2:2009, Plastics piping systems for water supply and for buried and above-ground drainage and
sewerage under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 2: Pipes
ISO 1452-3, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 3: Fittings
ISO 1452-4, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 4: Valves
ISO 1452-5, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 5: Fitness for purpose of the system
ISO 4065, Thermoplastics pipes — Universal wall thickness table
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ISO/TR 4191:2014(E)

ISO 4633, Rubber seals — Joint rings for water supply, drainage and sewerage pipelines — Specification for
materials
ISO 7387-1, Adhesives with solvents for assembly of PVC-U pipe elements — Characterization — Part 1:
Basic test methods
ISO 9080, Plastics piping and ducting systems — Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation
ISO 9311-1, Adhesives for thermoplastic piping systems — Part 1: Determination of film properties
ISO 9969, Thermoplastics pipes — Determination of ring stiffness
ISO/DIS 16422:2013, Pipes and joints made of oriented unplasticized poly(vinyl chloride) (PVC-O) for the
conveyance of water under pressure — Specifications
3 Terms and definitions, symbols, and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 1452-1:2009 and the following apply.
3.1.1
nominal outside diameter
d
n
numerical designation of size which is common to all components in a thermoplastics piping system
other than flanges and components designated by thread size
Note 1 to entry: It is a convenient round number for reference purposes.
Note 2 to entry: For pipe conforming to ISO 161-1, the nominal outside diameter, expressed in millimetres, is the
minimum mean outside diameter d .
em, min
3.1.2
nominal wall thickness
e
n
specified wall thickness, in millimetres
Note 1 to entry: It is identical to the specified minimum wall thickness at any point e .
y,min
3.1.3
nominal pressure (PN)
alphanumeric designation related to the mechanical characteristics of the components of a piping
system and used for reference purposes
3.1.4
hydrostatic pressure
p
internal pressure applied to a piping system
3.1.5
working pressure (PFA)
maximum pressure which a piping system can sustain in continuous use under given service conditions
without pressure surge
Note 1 to entry: For thermoplastics piping systems, the value of the nominal pressure is equal to the working
pressure at a temperature of 20 °C expressed in bars.
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ISO/TR 4191:2014(E)

3.1.6
hydrostatic stress
σ
stress induced in the wall of a pipe when it is subjected to internal water pressure
Note 1 to entry: The stress in megapascals is related to the internal pressure, p, in bars, the nominal wall thickness,
e , in millimetres, and the nominal outside diameter of the pipe, d , in millimetres by the following formula:
n n
pd ×−()e
nn
σ =
20e
n

Note 2 to entry: If σ and p are given in the same units, the denominator becomes 2en.
3.1.7
long-term hydrostatic strength at 20 °C
σ
lhts
quantity with the unit of stress, i.e. MPa, which can be considered to be a property of the material under
consideration and which represents the 97,5 % lower confidence limit for the long-term hydrostatic
strength and equals the predicted average strength at a temperature of 20 °C and a time of 50 years with
internal water pressure
Note 1 to entry: ISO 9080 gives the possibility to extrapolate to 100 year lifetime.
3.1.8
lower confidence limit of the predicted hydrostatic strength
σ
LPL
quantity with the dimension of stress, which represents the 97,5 % lower confidence limit of the
predicted hydrostatic strength for a single value at a temperature T and a time t
Note 1 to entry: It is denoted as σ = σ .
LPL (T,t,0,975)
Note 2 to entry: The value of this quantity is determined by the method given in ISO 9080.
3.1.9
minimum required strength
MRS
value of σ rounded to the next lower value of the R 10 series from ISO 3 when σ is below 10 MPa or
LPL LPL
to the next lower value of the R 20 series when σ is higher than 10 MPa
LPL
3.1.10
design coefficient
C
overall coefficient with a value greater than one, which takes into consideration service conditions, as
well as properties of the components of a piping system other than those represented in σ
LPL
3.1.11
pipe series S
dimensionless number for pipe designation (see ISO 4065)
3.1.12
standard dimension ratio
SDR
numerical designation of a pipe series which is a convenient round number approximately equal to the
dimension ratio of the nominal outside diameter, d , and the nominal wall thickness, e
n n
Note 1 to entry: According to ISO 4065, the standard dimension ratio, SDR, and the pipe series S are related as
follows:
[SDR] = 2[S] +1
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ISO/TR 4191:2014(E)

3.2 Symbols
C design coefficient
d outside diameter (at any point)
e
d mean outside diameter
em
d inside diameter (at any point)
i
d mean inside diameter of socket
im
d nominal (outside or inside) diameter
n
DN nominal size
E wall thickness (at any point)
e mean wall thickness
m
e nominal wall thickness
n
f derating ( uprating) factor for application
A or
f derating factor for temperatures
T
Δ material density
Σ hydrostatic stress
P internal hydrostatic pressure
p test pressure
T
σ design stress
s
σ stress at lower predicted confidence limit
LPL
3.3 Abbreviations
LPL lower predicted confidence limit
MRS minimum required strength
MOP maximum operating pressure
PFA allowable operating pressure
PEA allowable site test pressure
PN nominal pressure
DN nominal diameter
PVC-U unplasticized poly(vinyl chloride)
SDR standard dimension ratio
PVC-O oriented poly(vinyl chloride)
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ISO/TR 4191:2014(E)

4 Parameters influencing design
4.1 Allowable operating pressure
4.1.1 Where pipe material temperatures do not exceed 25 °C, and where no extra safety considerations
are applicable, nominal pressures are given in Table A.1 of ISO 1452-2:2009 and in Table 2 of
ISO/DIS 16422:2013. These nominal pressures have been calculated on the basis of well-established
data, taking into account a service life of at least 50 years of continuous operation. For common water
supply systems up to 25 °C, the allowable operating pressure PFA in bars (1 bar = 105 N/m2 = 0,1 MPa)
is equal to the nominal pressure, PN.
4.1.2 Design coefficient, C, should comply with those specified in ISO 1452, for PVC-U, and ISO 16422,
for PVC-O.
4.1.3 Where the water service temperature is between 25 °C and 45 °C, it is required that the maximum
allowable pressure is reduced by applying a derating factor, f , as shown in Figure A.1 of ISO 1452-2:2009
T
and Annex C of ISO/DIS 16422:2013.
Figure A.1 of ISO 1452-2:2009 shows that for temperatures up to and including 25 °C, the derating factor
to be applied is 1,0 and for temperatures above 25 °C, the derating factor reduces from 1,0 to 0,63 at
45 °C. The same is valid for PVC-O pipes.
Where water service temperatures are expected to exceed 45 °C, the manufacturer’s advice should be
obtained.
4.2 Ring stiffness of pipes
Where a calculation of the initial pipe deflection is applied, the initial ring stiffness of the pipe should be
taken from Table 1.
Table 1 — Initial ring stiffness of pipes
Pipe series
S 20 S 16,7 S 16 S 12,5 S 10 S 8 S 6,3 S 5
(SDR 41) (SDR 34,4) (SDR 33) (SDR 26) (SDR 21) (SDR 17) (SDR 13,6) (SDR 11)
Nominal pressure − PN 6 PN 6 PN 8 PN 10 PN 12,5 PN 16 PN 20
PN 6 PN 7,5 PN 8 PN 10 PN 12,5 PN 16 PN 20 PN 25
for d ≤90
n
for d >90
n
Calculated ring 3,9 6,7 7,6 16 31,3 61 125 250
2
stiffness in kN/m
(S
calc)
Nominal ring stiff-
4 8 − 16 32 − − −
ness SN
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ISO/TR 4191:2014(E)

The initial ring stiffness S in Table 1 has been calculated using the following formula:
calc
E×I E
S = =
calc
33
()de− 96[]S
en
(1)
where
S is the calculated initial ring stiffness in kilonewtons per square metre;
calc
E is the modulus of elasticity in flexure, having the value of 3,2 × 106 kN/m2 for PVC-U and
having the value of 4 × 106 kN/m2 for PVC-O;
3
1×e
n
Ι is the moment of inertia in cubic millimetres with for 1 m pipe length;
12
d is the nominal outside diameter in millimetres;
e
e is the nominal wall thickness in millimetres;
n
S is the pipe series.
The initial ring stiffness of PVC-O pipes with the different MRS values are given in the graphs of Figure 1.
6 2 6 2
E: PVC-O: 4 × 10 kN/m (4 000 Mpa) E: PVC-U: 3,2 × 10 kN/m (3 200 Mpa).
NOTE The following C factor has been used: MRS 250 (PVC-U): C = 2,0; PVC-O: C = 1,6.
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ISO/TR 4191:2014(E)

NOTE The following C factor has been used: PVC-O: C = 1,4.
Figure 1 — Initial ring stiffness of pipes of PVC-O
In case the actual modulus measured or stated by the manufacturer or designer is known, then use the
following correction formulae:
For PVC-U: SN = SN1 × E/3 200
For PVC-O: SN = SN1 × E/4 000
(SN1 = taken from the graph)
5 Hydraulic properties
5.1 Loss of head
For head losses through fittings, the manufacturer’s advice should be obtained.
PVC pressure pipes are specified by nominal diameters, d . Internal diameters vary according to pipe
n
series (see Table 2 of ISO 1452-2:2009 and ISO/DIS 16422:2013). This shall be taken into account when
calculating the flow characteristics of pipes.
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ISO/TR 4191:2014(E)

The flow is characterized by the Reynolds number as follows:
Re = v × dh/µ (2)
where
Re is the Reynolds number [-];
v is the flow speed [m/s];
2
µ is the kinematic viscosity [m /s].
The friction value f is then calculated by an iterative manner using Formula (3):
 
1 ε/D 25, 1
h
=−2log +
 
10
 
37,
f Re f
 
(3)
where
D is the hydraulic diameter (for a circular pipe, full flow = internal pipe diameter) [m];
h
Re is the Reynolds number [-];
ε is the roughness of the pipe [m].
And finally, the pressure loss is calculated by
2
L ρV
Δpf=× ×
D 2
(4)
where
∆p is the pressure loss [m];
f friction value;
L is the length of the pipe [m];
D is the internal diameter of the pipe [m];
3
ρ is the density of the fluid [kg/m ];
V is the flow speed [m/s].
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ISO/TR 4191:2014(E)

Figure 2 — Example of flow chart for head losses in pipes
Figure 2 comprises the friction loss diagram for PVC-U pipes calculated by L-E Janson in accordance with
Colebrook. For internal diameters up to 200 mm, k = 0,02 mm and for larger diameters, k = 0,05 mm. The
temperature of the water is ±10 °C.
6 Assembly methods
6.1 General
6.1.1 PVC pressure pipes conforming to ISO 1452-2:2009 are supplied in nominal lengths and with one
of the following three end conditions:
a) plain, for jointing by means of separate couplers;
b) integral elastomeric ring socket (one end), for push-fit jointing;
c) integral socket (one end), for solvent cement jointing.
6.1.2 Fittings of PVC for use with PVC pipes are specified in ISO 1452-3 and can either have socket-type
joints for solvent cementing or elastomeric ring joints for push-fit jointing. Valves and ancillaries of PVC-U
are specified in ISO 1452-4.
6.1.3 The principal types of joints and their characteristics are as follows:
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ISO/TR 4191:2014(E)

a) Lastomeric ring seal joints (see Figure 3). An elastomeric sealing ring is compressed and forms
a pressure-tight seal when a spigot is inserted into a socket. These joints do not sustain axial thrust
(non-end-load-bearing).
Figure 3 — Typical elastomeric ring seal joints
b) Solvent cement joints (see Figure 4). A solvent-based adhesive is applied to a spigot and to a
socket and the two components are pushed together. Solvent-cemented joints sustain axial thrust (end-
load-bearing).
Figure 4 — Typical solvent cement joints
c) Mechanical joints (see Figure 5). These joints can be either end-load-bearing or non-end-load-
bearing.
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ISO/TR 4191:2014(E)

Figure 5 — Typical mechanical joint
These joints, also known as compression joints, use separate couplers made from PVC-U, reinforced
plastics or metal, e.g. cast iron. A pressure-tight seal is achieved when an elastomeric sealing ring is
compressed by tightening backing ring(s) of various designs. These joints may or may not sustain axial
thrust (non-end-load-bearing). For the choice of specific mechanical couplers, advice shall be sought at
the manufacturer of the PVC pipes.
d) Flanged joints (see Figure 6). A flange is incorporated onto the end of a pipe or fitting in a
variety of ways. A pressure-tight seal is achieved by compressing a sealing gasket between the mating
faces of flanges on adjacent pipes, fittings, or valves made from plastics or metals. These joints can be
either end-load-bearing or non-end-load-bearing.
Figure 6 — Example of flanged joints
e) Union couplers and adaptors (see Figure 7). Union couplers and adaptors can be used for joint-
ing PVC pipes to PVC pipes and PVC pipes to metal pipe threads. Union couplers and adaptors sustain
axial thrust (end-load-bearing).
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ISO/TR 4191:2014(E)

Figure 7 — Union couplers and adaptors
Where pipe installations include non-end-load-bearing jointing systems (above or below ground), it is
essential to consider the probability of joint separation due to axial thr
...

SLOVENSKI STANDARD
oSIST-TP ISO/TR 4191:2018
01-julij-2018
&HYQLVLVWHPLL]SROLPHUQLKPDWHULDORY]DRVNUER]YRGR1HPHKþDQSROLYLQLONORULG
39&8LQRULHQWLUDQ39&839&21DYRGLOD]DYJUDGQMR
Plastics piping systems for water supply -- Unplasticized poly(vinyl chloride)(PVC-U) and
oriented PVC-U (PVC-O) -- Guidance for installation
Systèmes de canalisations en plastique pour l'alimentation en eau -- Polychlorure de
vinyle non plastifié (PVC-U) et orienté PVC-U (PVC-O) -- Pratique recommandée pour la
pose
Ta slovenski standard je istoveten z: ISO/TR 4191:2014
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
91.140.60 Sistemi za oskrbo z vodo Water supply systems
oSIST-TP ISO/TR 4191:2018 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST-TP ISO/TR 4191:2018

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oSIST-TP ISO/TR 4191:2018
TECHNICAL ISO/TR
REPORT 4191
Second edition
2014-01-15
Plastics piping systems for water
supply — Unplasticized poly(vinyl
chloride)(PVC-U) and oriented PVC-U
(PVC-O) — Guidance for installation
Systèmes de canalisations en plastique pour l’alimentation en eau —
Polychlorure de vinyle non plastifié (PVC-U) et orienté PVC-U (PVC-O)
— Pratique recommandée pour la pose
Reference number
ISO/TR 4191:2014(E)
©
ISO 2014

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oSIST-TP ISO/TR 4191:2018
ISO/TR 4191:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

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oSIST-TP ISO/TR 4191:2018
ISO/TR 4191:2014(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions, symbols, and abbreviations . 2
3.1 Terms and definitions . 2
3.2 Symbols . 4
3.3 Abbreviations . 4
4 Parameters influencing design . 5
4.1 Allowable operating pressure . 5
4.2 Ring stiffness of pipes . 5
5 Hydraulic properties . 7
5.1 Loss of head . 7
6 Assembly methods . 9
6.1 General . 9
6.2 Integral rubber ring joints .13
6.3 Solvent cement joints .14
6.4 Mechanical joints .15
7 Storage, handling, and transport of pipes .15
7.1 Handling.15
7.2 Transport .16
7.3 Storage .16
7.4 Cold bending on site .17
7.5 Anchoring and thrust blocks .19
8 Storage, handling, and transport of fittings, valves, and ancillaries .21
8.1 PVC-U fittings, valves, and ancillaries are light and easy to handle .21
9 Installation .22
9.1 Installation below ground .22
9.2 Pipe deflection .25
9.3 Installation above ground .27
9.4 Installation in ducts .31
10 Commissioning by site pressure testing .31
10.1 General .31
10.2 Preparation for test .31
10.3 Test pressures .35
10.4 Applying the test .35
10.5 Interpretation of results .36
11 Contaminated soil .36
12 Corrosion protection of metal parts .36
13 Pressure surge .37
14 Usage at lower temperature .37
15 Fatigue .37
16 Repairs .38
17 Pipeline detection .39
Annex A (informative) Classification of soils .40
Bibliography .44
© ISO 2014 – All rights reserved iii

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oSIST-TP ISO/TR 4191:2018
ISO/TR 4191:2014(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 2, Plastics pipes and fittings for water supplies.
This second edition cancels and replaces the first edition (ISO/TR 4191:1989), which has been technically
revised.
iv © ISO 2014 – All rights reserved

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oSIST-TP ISO/TR 4191:2018
ISO/TR 4191:2014(E)

Introduction
This Technical Report is a guidance document and gives a recommended practice for the installation
of unplasticized poly(vinyl chloride) (PVC-U) and oriented unplasticized poly(vinyl chloride) (PVC-O)
piping systems conveying water under pressure for buried and above-ground drainage and sewerage
systems.
Molecular orientation of PVC-U results in the improvement of physical and mechanical properties.
Unless specifically mentioned, the recommendations are valid for both PVC-U and PVC-O and expressed
as PVC.
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oSIST-TP ISO/TR 4191:2018
TECHNICAL REPORT ISO/TR 4191:2014(E)
Plastics piping systems for water supply — Unplasticized
poly(vinyl chloride)(PVC-U) and oriented PVC-U (PVC-O) —
Guidance for installation
1 Scope
This ISO Technical Report gives recommended practices for installation of unplasticized
poly(vinyl chloride) (PVC-U) and oriented unplasticized poly(vinyl chloride) (PVC-O) pipes, fittings,
valves, and ancillaries when used in piping systems conveying water under pressure.
The recommendations are intended to give practical guidance of design and installation of piping
systems incorporating pipes, fittings, valves, and ancillary equipment made from PVC materials and
used for the following purposes:
— water mains and services buried in ground;
— waste water under pressure;
— conveyance of water above ground for both outside and inside buildings,
for the supply of water under pressure at approximately 20 °C (cold water) intended for human
consumption and for general purposes.
This Technical report is also applicable to components for the conveyance of water up to and including
45 °C. For temperatures between 25 °C and 45 °C, Figure 1 of ISO 1452-2:2009 applies.
In addition, recommendations are given for the connection to fittings, valves, and ancillary equipment
made from materials other than PVC.
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.
ISO 3, Preferred numbers — Series of preferred numbers
ISO 161-1, Thermoplastics pipes for the conveyance of fluids — Nominal outside diameters and nominal
pressures — Part 1: Metric series
ISO 1452-1:2009, Plastics piping systems for water supply and for buried and above-ground drainage and
sewerage under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 1: General
ISO 1452-2:2009, Plastics piping systems for water supply and for buried and above-ground drainage and
sewerage under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 2: Pipes
ISO 1452-3, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 3: Fittings
ISO 1452-4, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 4: Valves
ISO 1452-5, Plastics piping systems for water supply and for buried and above-ground drainage and sewerage
under pressure — Unplasticized poly(vinyl chloride) (PVC-U) — Part 5: Fitness for purpose of the system
ISO 4065, Thermoplastics pipes — Universal wall thickness table
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ISO 4633, Rubber seals — Joint rings for water supply, drainage and sewerage pipelines — Specification for
materials
ISO 7387-1, Adhesives with solvents for assembly of PVC-U pipe elements — Characterization — Part 1:
Basic test methods
ISO 9080, Plastics piping and ducting systems — Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation
ISO 9311-1, Adhesives for thermoplastic piping systems — Part 1: Determination of film properties
ISO 9969, Thermoplastics pipes — Determination of ring stiffness
ISO/DIS 16422:2013, Pipes and joints made of oriented unplasticized poly(vinyl chloride) (PVC-O) for the
conveyance of water under pressure — Specifications
3 Terms and definitions, symbols, and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 1452-1:2009 and the following apply.
3.1.1
nominal outside diameter
d
n
numerical designation of size which is common to all components in a thermoplastics piping system
other than flanges and components designated by thread size
Note 1 to entry: It is a convenient round number for reference purposes.
Note 2 to entry: For pipe conforming to ISO 161-1, the nominal outside diameter, expressed in millimetres, is the
minimum mean outside diameter d .
em, min
3.1.2
nominal wall thickness
e
n
specified wall thickness, in millimetres
Note 1 to entry: It is identical to the specified minimum wall thickness at any point e .
y,min
3.1.3
nominal pressure (PN)
alphanumeric designation related to the mechanical characteristics of the components of a piping
system and used for reference purposes
3.1.4
hydrostatic pressure
p
internal pressure applied to a piping system
3.1.5
working pressure (PFA)
maximum pressure which a piping system can sustain in continuous use under given service conditions
without pressure surge
Note 1 to entry: For thermoplastics piping systems, the value of the nominal pressure is equal to the working
pressure at a temperature of 20 °C expressed in bars.
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3.1.6
hydrostatic stress
σ
stress induced in the wall of a pipe when it is subjected to internal water pressure
Note 1 to entry: The stress in megapascals is related to the internal pressure, p, in bars, the nominal wall thickness,
e , in millimetres, and the nominal outside diameter of the pipe, d , in millimetres by the following formula:
n n
pd ×−()e
nn
σ =
20e
n

Note 2 to entry: If σ and p are given in the same units, the denominator becomes 2en.
3.1.7
long-term hydrostatic strength at 20 °C
σ
lhts
quantity with the unit of stress, i.e. MPa, which can be considered to be a property of the material under
consideration and which represents the 97,5 % lower confidence limit for the long-term hydrostatic
strength and equals the predicted average strength at a temperature of 20 °C and a time of 50 years with
internal water pressure
Note 1 to entry: ISO 9080 gives the possibility to extrapolate to 100 year lifetime.
3.1.8
lower confidence limit of the predicted hydrostatic strength
σ
LPL
quantity with the dimension of stress, which represents the 97,5 % lower confidence limit of the
predicted hydrostatic strength for a single value at a temperature T and a time t
Note 1 to entry: It is denoted as σ = σ .
LPL (T,t,0,975)
Note 2 to entry: The value of this quantity is determined by the method given in ISO 9080.
3.1.9
minimum required strength
MRS
value of σ rounded to the next lower value of the R 10 series from ISO 3 when σ is below 10 MPa or
LPL LPL
to the next lower value of the R 20 series when σ is higher than 10 MPa
LPL
3.1.10
design coefficient
C
overall coefficient with a value greater than one, which takes into consideration service conditions, as
well as properties of the components of a piping system other than those represented in σ
LPL
3.1.11
pipe series S
dimensionless number for pipe designation (see ISO 4065)
3.1.12
standard dimension ratio
SDR
numerical designation of a pipe series which is a convenient round number approximately equal to the
dimension ratio of the nominal outside diameter, d , and the nominal wall thickness, e
n n
Note 1 to entry: According to ISO 4065, the standard dimension ratio, SDR, and the pipe series S are related as
follows:
[SDR] = 2[S] +1
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3.2 Symbols
C design coefficient
d outside diameter (at any point)
e
d mean outside diameter
em
d inside diameter (at any point)
i
d mean inside diameter of socket
im
d nominal (outside or inside) diameter
n
DN nominal size
E wall thickness (at any point)
e mean wall thickness
m
e nominal wall thickness
n
f derating ( uprating) factor for application
A or
f derating factor for temperatures
T
Δ material density
Σ hydrostatic stress
P internal hydrostatic pressure
p test pressure
T
σ design stress
s
σ stress at lower predicted confidence limit
LPL
3.3 Abbreviations
LPL lower predicted confidence limit
MRS minimum required strength
MOP maximum operating pressure
PFA allowable operating pressure
PEA allowable site test pressure
PN nominal pressure
DN nominal diameter
PVC-U unplasticized poly(vinyl chloride)
SDR standard dimension ratio
PVC-O oriented poly(vinyl chloride)
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4 Parameters influencing design
4.1 Allowable operating pressure
4.1.1 Where pipe material temperatures do not exceed 25 °C, and where no extra safety considerations
are applicable, nominal pressures are given in Table A.1 of ISO 1452-2:2009 and in Table 2 of
ISO/DIS 16422:2013. These nominal pressures have been calculated on the basis of well-established
data, taking into account a service life of at least 50 years of continuous operation. For common water
supply systems up to 25 °C, the allowable operating pressure PFA in bars (1 bar = 105 N/m2 = 0,1 MPa)
is equal to the nominal pressure, PN.
4.1.2 Design coefficient, C, should comply with those specified in ISO 1452, for PVC-U, and ISO 16422,
for PVC-O.
4.1.3 Where the water service temperature is between 25 °C and 45 °C, it is required that the maximum
allowable pressure is reduced by applying a derating factor, f , as shown in Figure A.1 of ISO 1452-2:2009
T
and Annex C of ISO/DIS 16422:2013.
Figure A.1 of ISO 1452-2:2009 shows that for temperatures up to and including 25 °C, the derating factor
to be applied is 1,0 and for temperatures above 25 °C, the derating factor reduces from 1,0 to 0,63 at
45 °C. The same is valid for PVC-O pipes.
Where water service temperatures are expected to exceed 45 °C, the manufacturer’s advice should be
obtained.
4.2 Ring stiffness of pipes
Where a calculation of the initial pipe deflection is applied, the initial ring stiffness of the pipe should be
taken from Table 1.
Table 1 — Initial ring stiffness of pipes
Pipe series
S 20 S 16,7 S 16 S 12,5 S 10 S 8 S 6,3 S 5
(SDR 41) (SDR 34,4) (SDR 33) (SDR 26) (SDR 21) (SDR 17) (SDR 13,6) (SDR 11)
Nominal pressure − PN 6 PN 6 PN 8 PN 10 PN 12,5 PN 16 PN 20
PN 6 PN 7,5 PN 8 PN 10 PN 12,5 PN 16 PN 20 PN 25
for d ≤90
n
for d >90
n
Calculated ring 3,9 6,7 7,6 16 31,3 61 125 250
2
stiffness in kN/m
(S
calc)
Nominal ring stiff-
4 8 − 16 32 − − −
ness SN
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The initial ring stiffness S in Table 1 has been calculated using the following formula:
calc
E×I E
S = =
calc
33
()de− 96[]S
en
(1)
where
S is the calculated initial ring stiffness in kilonewtons per square metre;
calc
E is the modulus of elasticity in flexure, having the value of 3,2 × 106 kN/m2 for PVC-U and
having the value of 4 × 106 kN/m2 for PVC-O;
3
1×e
n
Ι is the moment of inertia in cubic millimetres with for 1 m pipe length;
12
d is the nominal outside diameter in millimetres;
e
e is the nominal wall thickness in millimetres;
n
S is the pipe series.
The initial ring stiffness of PVC-O pipes with the different MRS values are given in the graphs of Figure 1.
6 2 6 2
E: PVC-O: 4 × 10 kN/m (4 000 Mpa) E: PVC-U: 3,2 × 10 kN/m (3 200 Mpa).
NOTE The following C factor has been used: MRS 250 (PVC-U): C = 2,0; PVC-O: C = 1,6.
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NOTE The following C factor has been used: PVC-O: C = 1,4.
Figure 1 — Initial ring stiffness of pipes of PVC-O
In case the actual modulus measured or stated by the manufacturer or designer is known, then use the
following correction formulae:
For PVC-U: SN = SN1 × E/3 200
For PVC-O: SN = SN1 × E/4 000
(SN1 = taken from the graph)
5 Hydraulic properties
5.1 Loss of head
For head losses through fittings, the manufacturer’s advice should be obtained.
PVC pressure pipes are specified by nominal diameters, d . Internal diameters vary according to pipe
n
series (see Table 2 of ISO 1452-2:2009 and ISO/DIS 16422:2013). This shall be taken into account when
calculating the flow characteristics of pipes.
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The flow is characterized by the Reynolds number as follows:
Re = v × dh/µ (2)
where
Re is the Reynolds number [-];
v is the flow speed [m/s];
2
µ is the kinematic viscosity [m /s].
The friction value f is then calculated by an iterative manner using Formula (3):
 
1 ε/D 25, 1
h
=−2log +
 
10
 
37,
f Re f
 
(3)
where
D is the hydraulic diameter (for a circular pipe, full flow = internal pipe diameter) [m];
h
Re is the Reynolds number [-];
ε is the roughness of the pipe [m].
And finally, the pressure loss is calculated by
2
L ρV
Δpf=× ×
D 2
(4)
where
∆p is the pressure loss [m];
f friction value;
L is the length of the pipe [m];
D is the internal diameter of the pipe [m];
3
ρ is the density of the fluid [kg/m ];
V is the flow speed [m/s].
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Figure 2 — Example of flow chart for head losses in pipes
Figure 2 comprises the friction loss diagram for PVC-U pipes calculated by L-E Janson in accordance with
Colebrook. For internal diameters up to 200 mm, k = 0,02 mm and for larger diameters, k = 0,05 mm. The
temperature of the water is ±10 °C.
6 Assembly methods
6.1 General
6.1.1 PVC pressure pipes conforming to ISO 1452-2:2009 are supplied in nominal lengths and with one
of the following three end conditions:
a) plain, for jointing by means of separate couplers;
b) integral elastomeric ring socket (one end), for push-fit jointing;
c) integral socket (one end), for solvent cement jointing.
6.1.2 Fittings of PVC for use with PVC pipes are specified in ISO 1452-3 and can either have socket-type
joints for solvent cementing or elastomeric ring joints for push-fit jointing. Valves and ancillaries of PVC-U
are specified in ISO 1452-4.
6.1.3 The principal types of joints and their characteristics are as follows:
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a) Lastomeric ring seal joints (see Figure 3). An elastomeric sealing ring is compressed and forms
a pressure-tight seal when a spigot is inserted into a socket. These joints do not sustain axial thrust
(non-end-load-bearing).
Figure 3 — Typical elastomeric ring seal joints
b) Solvent cement joints (see Figure 4). A solvent-based adhesive is applied to a spigot and to a
socket and the two components are pushed together. Solvent-cemented joints sustain axial thrust (end-
load-bearing).
Figure 4 — Typical solvent cement joints
c) Mechanical joints (see Figure 5). These joints can be either end-load-bearing or non-end-load-
bearing.
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