ENV 1452-6:2001

SLOVENSKI STANDARD
01-junij-2002
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Plastics piping systems for water supply - Unplasticized poly(vinyl chloride) (PVC-U) -
Part 6: Guidance for installation
Kunststoff-Rohrleitungssysteme für die Wasserversorgung - Weichmacherfreies
Polyvinylchlorid (PVC-U) - Teil 6: Empfehlungen für die Verlegung
Systemes de canalisations en plastique pour l'alimentation en eau - Poly(chlorure de
vinyle) non plastifié (PVC-U) - Partie 6: Guide pour la pose
Ta slovenski standard je istoveten z: ENV 1452-6:2001
ICS:
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
91.140.60 Sistemi za oskrbo z vodo Water supply systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN PRESTANDARD
ENV 1452-6
PRÉNORME EUROPÉENNE
EUROPÄISCHE VORNORM
November 2001
ICS 91.140.60
English version
Plastics piping systems for water supply - Unplasticized
poly(vinyl chloride) (PVC-U) - Part 6: Guidance for installation
Systèmes de canalisations en plastique pour alimentation Kunststoff-Rohrleitungssysteme für die Wasserversorgung
en eau - Poly(chlorure de vinyle) non plastifié (PVC-U) - - Weichmacherfreies Polyvinylchlorid (PVC-U) - Teil 6:
Partie 6: Guide pour la pose Empfehlungen für die Verlegung
This European Prestandard (ENV) was approved by CEN on 14 November 1999 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 1452-6:2001 E
worldwide for CEN national Members.

Contents
Page
Introduction .3
1 Scope.5
2 Normative references.5
3 Definitions, symbols and abbreviations.5
4 Parameters influencing design .5
4.1 Allowable operating pressure .5
4.2 Ring stiffness of pipes .6
4.3 Precautions.7
5 Hydraulic properties.7
5.1 Loss of head.7
5.2 Internal diameter.7
6 Assembly methods.7
6.1 General.7
6.2 Integral rubber ring joints.8
6.3 Solvent cement joints .9
6.4 Mechanical joints .10
7 Cold bending on site .10
8 Storage, handling and transport of pipes .11
8.1 Storage .11
8.2 Handling.12
8.3 Transportation of loose pipes .12
9 Storage, handling and transport of fittings, valves and ancillaries .12
10 Installation.13
10.1 General.13
10.2 Installation below ground.13
10.3 Installation above ground.15
10.4 Installation in ducts .16
11 Site pressure testing .16
11.1 General.16
11.2 Preparation for test.16
11.3 Test pressures.17
11.4 Applying the test .18
11.5 Interpretation of results.18
12 Corrosion protection.18
13 Pressure surge.19
14 Repairs.19
15 Pipeline detection.19
Annex A (informative) Hydraulic flow chart.20
Annex B (normative) Figures and tables referred to in this prestandard .21
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. It has been prepared in
collaboration with Eureau and in liaison with CEN/TC 164 "Water supply".
This prestandard is a Part of a System Standard for plastics piping systems of a particular material for
a specified application. There are a number of such System Standards.
System Standards are based on the results of the work 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).
They are supported by separate standards on test methods to which references are made throughout
the System Standard.
The System Standards are consistent with general standards on functional requirements and on
recommended practice for installation.
This European Prestandard is a guidance document and gives a recommended practice for the
installation of PVC-U piping systems conveying water under pressure.
EN 1452 consists of the following Parts, under the general title Plastics piping systems for water
supply
Unplasticized poly(vinyl chloride) (PVC-U)

  Part 1: General

 Part 2: Pipes

 Part 3: Fittings

 Part 4: Valves and ancillary equipment

 Part 5: Fitness for purpose of the system

 Part 6: Guidance for installation (this prestandard)

 Part 7: Guidance for the assessment of conformity (ENV).
This prestandard includes the following:

 Annex A (informative): Hydraulic flow chart

 Annex B (normative): Figures and tables

 Bibliography
At the date of publication of this prestandard, Systems Standards for piping systems of other plastics
materials used for the same application are the following:
NOTE All listed System Standards have reached the Enquiry stage or are under preparation.
EN 1796, Plastics piping systems for water supply with or without pressure
Glass-reinforced
thermosetting plastics (GRP) based on polyester resin (UP)
EN 12201, Plastics piping systems for water supply
Polyethylene (PE)
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
The System Standard, of which this is Part 6, specifies the requirements for a piping system and its
components when made from unplasticized poly(vinyl chloride) (PVC-U). The piping system is
intended to be used for water supply.
The System Standard also includes guidance for installation (this Part) and for the assessment of
conformity.
1  Scope
This European prestandard gives recommended practices for installation of unplasticized
poly(vinyl chloride) (PVC-U) pipes, fittings, valves and ancillaries when used in piping systems
conveying water under pressure.
The recommendations are intended to give practical guidance for the best methods of design and
installation of piping systems incorporating pipes, fittings, valves and ancillary equipment made from
PVC-U materials and used for the following purposes:
a) water mains and services buried in ground;
b) 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 prestandard 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 A.1 of EN 1452-2:1999 applies.
In addition, recommendations are given for the connection to fittings, valves and ancillary equipment
made from materials other than PVC-U.
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 amentments).
ENV 1046, Plastics piping and ducting systems — Systems outside building structures for the
conveyance of water or sewage — Guidance for installation above and below ground
EN 1452-1:1999, Plastics piping systems for water supply — Unplasticized poly(vinyl chloride)
(PVC-U) — Part 1: General
EN 1452-2:1999, Plastics piping systems for water supply — Unplasticized poly(vinyl chloride)
(PVC-U) — Part 2: Pipes
3  Definitions, symbols and abbreviations
For the purposes of this prestandard, the definitions, symbols and abbreviations given in ENV 1046
together with those given in EN 1452-1:1999 apply.
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 (see 4.1.2), nominal pressures are given in Table A.1 of
EN 1452-2:1999 using an overall service (design) coefficient, C, of 2,5 for d up to and including
n
90 mm and 2,0 for d greater than 90 mm. These nominal pressures have been calculated on the
n
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
1)
bars , is equal to the nominal pressure PN.

5 2
) 1 bar = 10 N/m = 0,1 MPa
4.1.2  In order to satisfy special users' requirements, an overall service (design) coefficient, C, other
than 2,5 and 2,0 but not lower than 1,6 may be applied.
4.1.3  Where the water service temperature is between 25 °C and 45 °C, then EN 1452-2:1999
requires that the maximum allowable pressure is reduced by applying a derating factor, f as shown in
,
T
Figure A.1 of EN 1452-2:1999.
Figure A.1 of EN 1452-2:1999 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.
Where water service temperatures are expected to exceed 45 °C, the manufacturer's advice should
be obtained.
For an example of the application of a derating factor see Figure A.1 of EN 1452-2:1999.
4.2  Ring stiffness of pipes
Where a calculation of the initial pipe deflection is applied, the initial ring stiffness of the pipe shall 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
for d  90
PN 6 PN 6 PN  8 PN 10 PN 12,5 PN 16 PN 20
n
for d  90 PN 6 PN 7,5 PN 8 PN 10 PN 12,5 PN 16 PN 20 PN 25
n
Calculated ring
stiffness in kN/m 3,9 6,7 7,6 16 31,3 61 125 250
(S
calc)
Nominal ring
48
16 32



stiffness SN
The initial ring stiffness S in Table 1 has been calculated using the following equation:
calc
E I E
S  
calc
3 3
(d
e ) 96[S]
e n
where:
S is the calculated initial ring stiffness in kilonewtons per square metre;
calc
6 2
E is the modulus of elasticity in flexure, having the value of 3  10 kN/m ;
1 e
n
 is the moment of inertia in cubic millimetres with for 1 m pipe length;
d
is the nominal outside diameter in millimetres;
e
e
is the nominal wall thickness in millimetres;
n
S is the pipe series.
NOTE 1 In practice the initial ring stiffness is always higher than calculated, because the average wall thickness is greater
than the nominal wall thickness used for the calculation.
NOTE 2 When pipes with nominal ring stiffness SN  4 are installed below ground, care should be taken to avoid
excessive ovalization (see also 10.2.4 and ENV 1046).
4.3  Precautions
4.3.1  For selecting pipe stiffness for different soil conditions, the recommendations given in
ENV 1046 apply.
4.3.2  Components of the pipeline systems shall not be exposed to flames or to radiant heat which is
likely to raise their surface temperatures.
4.3.3  Where regulations authorise the use of metal pipes for earthing and such pipes are replaced by
PVC-U, arrangements should be made to ensure that the electrical earth is maintained (see 4.3.4).
4.3.4  PVC-U does not conduct electricity and thus cannot be used for earthing; neither can these
pipes be thawed by electrical means using the pipe as a conductor. If a network exists of metal pipes
with a cathodic protection system and part of the network is replaced with PVC-U pipes, electrical
continuity shall be maintained by bridging the PVC-U pipes.
4.3.5  Because of the high electrical resistance of PVC-U pipes, precautions should be taken where
hazards would arise through static electricity.
4.3.6  Joints and bends shall not be post formed on site by the application of heat. For cold bending
of pipes, see clause 7.
4.3.7  Reasonable precautions should be taken when laying pipes made from any material. Because
PVC-U pipes become less ductile at low temperatures, additional care should be taken when handling
and installing pipes at 0 °C and below.
4.3.8  Pipes should not be coated or painted with solvent-containing or aggressive paints.
5  Hydraulic properties
5.1  Loss of head
See Annex A of this prestandard for the relevant flow chart, showing the head losses in PVC-U pipes.
For head losses through fittings, the manufacturer's advice should be obtained.
5.2  Internal diameter
PVC-U pressure pipes are specified by nominal diameters, d . Internal diameters vary according to
n
pipe series (see Table 2 of EN 1452-2:1999). This shall be taken into account when calculating the
flow characteristics of pipes.
6  Assembly methods
6.1  General
6.1.1  PVC-U pressure pipes conforming to EN 1452-2:1999 are manufactured by a continuous
extrusion process. Pipes are supplied in nominal lengths as described in EN 1452-2:1999 and with
one of the following three end conditions:
 plain, for jointing by means of separate couplers;
 integral elastomeric ring socket (one end), for push-fit jointing;
 integral socket (one end), for solvent cement jointing.
(See also 6.1.3.)
[1]
6.1.2  Fittings of PVC-U for use with PVC-U pipes are specified in EN 1452-3 and can either have
socket type joints for solvent cementing or elastomeric ring joints for push-fit jointing. Valves and
[2]
ancillaries of PVC-U are specified in EN 1452-4 . See also 6.1.3 as follows.
6.1.3  The principal types of joints and their characteristics (See Annex B for typical details) are as
follows:
a) elastomeric ring seal joints (see Figure B.1)
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).
b) solvent cement joints (see Figure B.2)
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).
c) mechanical joints (see Figure B.3)
These joints, also known as compression joints, use separate couplers made from PVC-U or
metal. A pressure-tight seal is achieved when an elastomeric sealing ring is compressed by
tightening backing ring(s) of various designs. These joints do not sustain axial thrust (non-end-
load-bearing).
d) flanged joints (see Figure B.4)
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.
e) union couplers and adaptors (see Figure B.5)
For unions an elastomeric seal is compressed between mating faces, which are held together by
means of a threaded back nut. Union couplers and adaptors can be used for jointing PVC-U
pipes to PVC-U pipes and PVC-U pipes to metal pipe threads. Union couplers and adaptors
sustain axial thrust (end-load-bearing).
Special elastomeric ring couplers are available that sustain axial thrust (see Figure B.6).
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 thrust.
In below-ground applications, joint separation can be prevented by means of end-load-bearing joints
or concrete anchor blocks (see Figure B.7). In certain circumstances the frictional resistance at the
interface of pipe and compacted backfill material might be sufficient to resist the axial forces
generated.
Joint separation in above ground applications can be prevented by properly designed anchor brackets
or more easily by use of end-load-bearing jointing systems.
Where large diameter pipes operating at high pressures are involved, axial thrusts of several tens of
kilonewtons can be developed, particularly during pressure testing operations (see Table B.1).
6.1.4  When it is known at the design stage that the pipeline will be required to be dismantled during
the course of its functional lifetime then an appropriate type of joint should be used.
6.2  Integral rubber ring joints
6.2.1  An integral rubber ring joint consists of an elastomeric sealing element located in a groove in
the socket formed integrally with the pipe or fitting. The sealing element (sealing ring) is compressed
to form a pressure-tight seal when the spigot end of a pipe or fitting is inserted into the socket.
Profiles of the ring and of the socket depend on individual manufacturers' designs. The rings to be
used shall be those supplied by the manufacturer for his own assembly system. If the sealing ring is
not in place at the time of delivery, the groove should be cleaned, any foreign bodies removed and the
ring located into the groove as directed by the manufacturer.
6.2.2  In order to meet water quality and biodegradation requirements, elastomeric sealing rings are
usually made from synthetic materials, e.g. ethylene-propylene-diene (EPDM) copolymer,
styrene-butadiene (SB) rubber or a combination of synthetic and natural rubber.
6.2.3  Integral elastomeric ring joints do not normally sustain end thrust. Particular attention should
be paid to the correct design of anchor blocks and to their location in the pipeline system (see 10.2.8).
Anchorage blocks should be designed to sustain the maximum thrust developed due to internal
pressure when the test pressure is applied. Examples of anchor block design, location and
construction are shown in Figure B.7. A table of forces generated is given in Table B.1.
In some European countries it is common practice to provide restraint against thrust by the inclusion of
end-load-bearing joints at strategic points within the system. Where this practice is acceptable, the
pipe and/or fittings manufacturer's advice should be sought to help identify the places where end-load-
bearing joints should be applied. See 10.2.8.
6.2.4  Correct assembly of an elastomeric ring seal joint requires that the spigot end of the pipe be
chamfered and correctly lubricated prior to insertion into the socket. Lubricant should also be applied
to the elastomeric ring once this is fitted into the ring groove.
The lubricant used should not have any detrimental effect on the pipe, fittings, ancillaries or
elastomeric sealing ring and shall not be toxic, shall not impart any taste or odour to the water and
shall not encourage the growth of bacteria.
In conformity to 4.2 of EN 1452-1:1999, the lubricant shall have no influence on water quality. Only
lubricants recommended by the pipe or fittings supplier should be used.
As soon as the pipe spigot and elastomeric ring have been lubricated, the spigot should be introduced
into the socket so as to avoid any risk of soiling or pollution.
After aligning the pipes in both horizontal and vertical planes, the spigot end should be inserted into
the socket up to the reference mark on the spigot.
Pipes may be cut on site. If this is necessary the cut should be square and the cut end deburred
and/or chamfered to the angle and dimensions given in EN 1452-2:1999.
6.3  Solvent cement joints
6.3.1 General
6.3.1.1  The dimensions of the sockets and spigots for solvent cement joints are given in
EN 1452-2:1999.
6.3.1.2  The solvent cement adhesives should conform to the functional requirements of the
appropriate standards and their identification characteristics should be specified by the manufacturer
[3]
according to ISO 7387-1 .
6.3.1.3  In conformity to EN 1452-1:1999, the solvent cements shall have no influence on water
quality.
6.3.2  Jointing operations
6.3.2.1  Solvent cement adhesives and cleaning fluids are flammable, therefore it is important that
smoking be prohibited in the area in which these materials are being used. Solvent cement operations
should be carried out in a well-ventilated area. Solvent cements and cleaning fluids can be
detrimental to health if inhaled or in contact with the skin.
6.3.2.2  The solvent cement should have the appropriate viscosity, it should not be diluted or stirred
unless otherwise instructed by the adhesive's manufacturer.
6.3.2.3  The pipe end to be jointed shall be cut square to its axis and free from irregularities such as
burrs and swarf. It should be chamfered as specified in EN 1452-2:1999 to prevent excessive
amounts of adhesive being scraped off the socket. When the chamfer is applied on site, the angle
and dimensions should conform to EN 1452-2:1999.
6.3.2.4  Both the spigot and socket should be thoroughly cleaned and abraded with glass paper or
emery cloth. Excessive abrasion shall be avoided.
6.3.2.5  The surfaces to be jointed should be clean, dry and free from grease. It is recommended that
a degreasing agent is used for this purpose.
6.3.2.6  The solvent cement should be applied in an even layer and in a longitudinal direction to both
spigot and socket mating surfaces.
6.3.2.7  The application of the solvent cement should be performed quickly. For diameters greater
than 110 mm, two persons are necessary to apply the adhesive, one to the spigot end and one to the
socket simultaneously.
6.3.2.8  Immediately and without twisting, the spigot should be pushed into the socket to the required
depth. Excessive amounts of adhesive around the socket mouth should be removed as soon as the
joint has been made. Once the joint is made, leave to dry without disturbing for at least 5 min for sizes
up to and including 63 mm, and 30 min for all sizes greater than 63 mm.
6.3.2.9  The joint becomes resistant to pressure only after an additional period. Allow the required
minimum time given by the solvent cement manufacturers (approximately 24 h) before applying the
maximum recommended test pressure (see clause 11).
NOTE Solvent cements are slow to cure at low temperatures and cure fast at high temperatures. Solvent cementing is
not recommended at temperatures of 0 °C and below.
6.4  Mechanical joints
6.4.1  Compression joints
Compression joints are normally separate fittings made from PVC-U or metal and can be in the form
of a coupler for connecting pipes and fittings of the same material and of the same dimensions, or as
an adaptor for connecting components of different materials and/or dimensions. Generally,
compression fittings consist of four main elements:
 body;
 elastomeric sealing rings;
 backing (compression) rings;
 nuts or bolts.
Each element is positioned on the pipe separately and the sealing rings compressed between the
body of the fitting and the pipe by tightening the backing rings. Nuts or bolts should not be
overtightened and the manufacturer's recommendations followed at all stages of assembly.
6.4.2  Threaded joints
There is a range of threaded joints for assembly to metallic pipes, including the following:
 PVC-U and metal union adaptor [see Figure B.5b)];
 PVC-U adaptor fittings [see Figures B.5c) and B.5d)].
PVC-U pipes conforming to EN 1452-2:1999 are not suitable for threading.
6.4.3 Flanged joints
PVC-U pipes, fittings and ancillaries can be supplied with flanged ends. Although detailed flange
designs vary considerably, all are suitable for connection to pipes, fittings and valves made from
dissimilar materials, e.g. metals. A pressure-tight joint is obtained by compressing a gasket or ring
between the mating faces of adjacent flanges.
7  Cold bending on site
It is permitted for pipes to deviate from one continuous straight line by either of the following
techniques:
a) means of a slight deflection within a elastomeric ring joint;
b) the gradual curvature of each pipe length.
To ensure that the efficiency of the elastomeric ring seal is not impaired, deflection within the joint
would normally be limited to a maximum of 1°. For greater deflections, special designs of joint should
be used and the manufacturer's advice obtained. The radius of curvature, R, of a cold-formed bend
over the length of a 6 m pipe shall not be less than 300 times the external diameter of the pipe (see
Figure B.8). Table B.2 gives useful dimensions for cold-bent pipes up to and including a d of
n
160 mm.
Pipes of diameters greater than 160 mm are regarded as rigid pipes and should not be subjected to
cold bending. For changes in direction of pipelines greater than 180 mm diameter long-radius pre-
formed bends should always be used. Pipes should not be subjected to cold bending when ambient
temperatures are less than 5 °C.
8  Storage, handling and transport of pipes
8.1  Storage
8.1.1  PVC-U pipes are light and easy to handle and consequently more likely to be mistreated for that
reason than metallic pipes. Appropriate precautions should be taken during handling and storage to
ensure that pipes are not damaged.
8.1.2  PVC-U pipes should be stacked on a surface sufficiently flat and free from sharp objects,
stones or projections in order to avoid deformation or damage to the pipes.
8.1.3  Lateral supports to pipe stacks should be provided at maximum intervals of 1,5 m. These
supports can be timber posts at least 50 mm wide.
8.1.4  Pipes should be supported evenly over their whole length. If this is not possible, the bottom
layer of pipes should be supported on wooden battens of at least 50 mm usable width, and spaced not
greater than 2 m apart. If the pipes are in bundles of approximately 1 m  1 m, supports may be
spaced up to 3 m apart. Pipes of different diameters and different thicknesses should be stacked
separately. If this is not possible, the largest and thickest pipes should be placed at the bottom.
8.1.5  When stacking pipes with integral sockets at one end, the sockets should be alternated within
the pile and should project sufficiently for the pipes to be correctly supported along their whole length.
8.1.6  Where pipes are supplied with end caps, plugs or wrappings, these should not be removed
before the pipes are put in place. Contact with fuels, solvents and paints should be avoided.
8.1.7  In depots or stores, bundled pipes should be stacked no more than three units or 2 m high,
whichever is the lower. At the construction site, bundles should be stacked no more than two units or
1 m high, whichever is the lower. If the bundles are timber framed, they should be stacked timber to
timber. Provision should be made for side supports, to prevent stack collapse, when banding or
framing is removed. Side supports should be spaced at centres not greater than 3 m (see Figure B.9).
Individual pipes in stacks in depots or stores should not exceed seven layers in height with a
maximum height of 1,5 m, but on a construction site stacks should have a maximum height of 1 m.
The width of the bottom layer should not exceed 3 m. The method of stacking should ensure that
there is uniform support along the pipe (e.g. spigot and socket pipes should be placed with the socket
protruding at alternate ends of the stack). The bottom layer of pipes can require thicker timber
bearers at spacings not greater than 2 m, so that the sockets do not bear directly on the ground. Stout
timber vertical supports and chocks should be provided as required to prevent accidental slipping,
rolling or collapse of the stack.
8.1.8  Prolonged exposure to strong ultra-violet light (sunlight) can slightly reduce the impact strength
of PVC-U pipes and cause discoloration. Nevertheless, the resistance to internal water pressure is not
reduced. Suitable protection by a free-venting opaque cover (canvas or polyethylene sheeting) is
recommended if the total exposed storage time is likely to exceed 12 months.
8.1.9  Pipes should be stored away from any heat source and should not be in contact with any other
potential hazards such as diesel oils, paints or solvents.
Pipes and fittings should be used in the order of delivery to ensure the correct rotation of stock.
PVC-U pipes are date marked at the time of manufacture and checks should be made to ensure the
stock is being rotated on an "oldest out first" basis.
8.2  Handling
8.2.1  When pipes are to be handled individually, they should be lowered, lifted and carried in a
controlled fashion and should never be thrown, dropped or dragged (see Figure B.10). Single pipes
up to nominal size 250 mm can be handled by two men without difficulty. Pipes of larger nominal size
can require lifting apparatus, as with bundles.
8.2.2  Unloading bundled pipes require the use of appropriate mechanical equipment. The chosen
technique should not cause damage to the pipes, e.g. forklift truck with flat protected forks or suitable
crane with spreader bars. PVC-U pipes should never be lifted using wire ropes and slings or metal
hooks and chains. Slings should be non-metallic, e.g. rope or webbing.
8.2.3  If the pipes have been telescoped (nested) for transporting, the inner pipes should always be
removed first and stacked separately.
8.2.4  The impact resistance of PVC-U pipes is reduced in cold weather and more care needs to be
taken when handling the material at temperatures below 0 °C. If temperatures fall below -15 °C,
special instructions from the manufacturer should be obtained.
8.3  Transportation of loose pipes
8.3.1  When transporting pipes, flat bed vehicles should be used. The bed should be free from nails
and other projections. When practicable, pipes should rest uniformly on the vehicle over their whole
length.
8.3.2  The vehicles should have side supports appropriately spaced approximately 2 m apart, and the
pipes should be secured effectively during transport. All posts should be flat with no sharp edges.
8.3.3  When loading socketed pipes, the pipes should be stacked on the vehicle so that the sockets
do not take excessive loads.
8.3.4  Where pipes overhang the vehicle, the amount of overhang should not exceed 1 m (see
Figure B.10).
8.3.5  High stiffness pipes should be placed at the bottom of the load and low stiffness pipes at the
top.
8.3.6  Care should be taken to avoid positioning the pipes near to any exhaust systems or any other
potential hazards such as diesel oil, paints or solvents.
8.3.7  Pipes should be inspected by the purchaser or his representative prior to off loading.
8.3.8  When pipes are transported in bundles, the bundles should be secured effectively and off
loaded as described in 8.2.
9  Storage, handling and transport of fittings, valves and ancillaries
9.1  PVC-U fittings, valves and ancillaries are light and easy to handle and consequently more likely to
be mistreated for that reason than components of metallic materials.
Throughout all stages of storage, handling and transport they should be preserved from damage and
contamination and be kept separate from and not temporarily jointed to the pipes until required for
installation. When fittings are provided packaged, they should be retained in the individual package
provided by the supplier, together with all associated rings, gaskets, nuts, bolts and accessories.
9.2  The impact resistance of PVC-U fittings, valves and ancillaries is reduced in cold weather and
more care needs to be taken when handling these products at temperatures below 0 °C. If
temperatures fall below
15 °C, special instructions from the manufacturer should be obtained.
Fittings, valves and ancillaries should be used in the order of delivery to ensure the correct rotation of
stock. Products are date marked at the time of manufacture and checks should be made to ensure
the stock is being rotated on an "oldest out first" basis.
10  Installation
10.1  General
10.1.1  The long-term performance of PVC-U pressure pipelines is directly affected by the quality of
workmanship and materials used in installing the product. Competent supervision of all stages is
recommended.
10.1.2  Reasonable care should be taken when handling and installing PVC-U pipes and components.
Particular care should be taken when installing PVC-U systems at temperatures below 0 °C. If
temperatures fall below -15 °C, special instructions from the manufacturer should be obtained. At no
time during the installation, testing or operation of the system should water be allowed to freeze in the
pipes or fittings. Where this condition may apply, appropriate precautions, (e.g. thermal insulation)
should be taken.
10.2  Installation below ground
10.2.1  Pipes and fittings with elastomeric ring seal joints are recommended for installations below
ground. Solvent cement joints can also be used for below ground applications and special advice
from the manufacturer should be obtained.
10.2.2  Typical trench and backfill details for PVC-U pressure pipe installations are shown in
Figure B.11.
10.2.3  Whilst not essential, it is good practice to lay pipes with the spigot entered into the socket in
the same direction as the intended flow of water. The internal surfaces of the pipe should be kept as
clean as possible during the laying and jointing operation. To assist in this respect, the trench should
be kept as dry as possible using appropriate dewatering techniques.
10.2.4  Suitable material for both bedding and side fill may be available by selection from the 'as dug'
excavated material. Such soils as free draining coarse sand, gravel and soils of a friable nature are
considered suitable (see ENV 1046).
'As dug' material should be free from boulders, sharp stones, flints, lumps of clay, chalk or frozen
earth. Contaminated soil and any organic matter should be discarded. Where excavated material is
not suitable, imported granular material should be used (see ENV 1046). Under no circumstances
should frozen backfill or frozen imported aggregates be used as bedding or sidefill materials.
The pipes should never be encased in concrete.
NOTE Encasing in concrete transforms a flexible pipe into a rigid structure with no flexural strength, which is likely to
fracture in the event of settlement or other movements of the earth.
For high static and/or surcharge loads, it is important to use pipes of an appropriate stiffness in order
to ensure the initial deformation of the pipe is maintained within a limit of 5 % maximum. Longer-term
deformation will be affected by the operation of the system. Systems continuously subjected to
internal water pressure will deform less than those left for long periods of time at zero pressure.
The minimum depth of cover recommended for buried water pipes is 0,9 m. However pipes should
always be laid at a frost-free depth, therefore where local climatic conditions so dictate the minimum
depth of cover may be in excess of 0,9 m.
Pipes laid beneath heavily trafficked areas, where a minimum cover depth of 0,9 m cannot be
maintained, will require additional protection. In such circumstances the pipe manufacturer's advice
should be obtained.
10.2.5  The base of the trench should be carefully levelled and cleared of any sharp objects, edges
and stones. If this is not possible, suitable material should be imported and laid as a bed of 0,1 m
minimum thickness. The trench bottom or bedding material should be excavated locally to
accommodate the larger diameter of the joints.
10.2.6  Pipes should be laid along the centre-line of the trench with all joints laid in true alignment,
unless deflected in accordance with clause 7.
10.2.7  The pipes are laid on the prepared bed. Where push-fit elastomeric sealing ring joints are
used, the spigot should be introduced into the socket and the insertion completed up to the mark on
the spigot pipe by use of a block of wood and a lever. Where mechanical means are used to push
together large diameter pipes, care should be taken to avoid damaging the materials or displacing the
elastomeric sealing ring. On completion of pipe laying and partial backfilling it is advisable to defer
final tie-in connections until thermal equilibrium of the pipeline has been attained.
10.2.8  Elastomeric ring seal joints as described in 6.1.3 and 6.2 will not sustain thrust caused by
internal pressure. Properly designed concrete anchor blocks or appropriate end-load-bearing joints
should be provided at all changes of direction, tees, blank ends, large reductions in diameter and
valves. Where concrete anchor blocks are used, the purpose of the anchor block is to transfer the
total thrust to the trench sides. It is therefore important to take account of the load-bearing capacity of
the surrounding ground. Where concrete would be in direct contact with the pipes or fittings, these
should be wrapped with a compressible material to accommodate creep and prevent the occurrence
of high local stress concentrations. The compressible material should not contain substances, which
could attack the pipe, e.g. plasticisers. Typical details and thrusts generated are given in Figure B.7
and Table B.1.
Where it is permitted to include end-load-bearing joints as an alternative to concrete anchor blocks,
the end-load-bearing joints should be provided at all connections to the components (e.g. tees, blank
ends, bends, large reducers and valves) and additionally at the first joint in the straight pipes
immediately adjacent to and on all sides of the fitting. This should be considered a minimum
requirement. In some cases it can be necessary to provide more than one end-load-bearing joint in
the straight pipes. If in doubt, the pipe manufacturer's advice should be obtained.
10.2.9  A recommended sequence for placing sidefill and surround material is shown in Figure B.11.
Where selected material is returned to the trench, it should be placed in layers. The first sidefill layer
should be placed and compacted under the lower quadrants of the pipe and up to the spring level of
the pipe. For pipes up to nominal outside diameter 225 mm "trampling" or "heeling" is usually an
effective means of achieving adequate compaction. Successive la
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